ORCID Profile
0000-0002-3762-0911
Current Organisations
American Academy Of Optometry
,
Deakin University
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Publisher: Informa UK Limited
Date: 10-03-2021
DOI: 10.1111/CXO.13143
Publisher: Elsevier BV
Date: 06-2022
DOI: 10.1016/J.PLEFA.2006.03.010
Abstract: Failure to provide omega 3 fatty acids in the perinatal period results in alterations in nerve growth factor levels, dopamine production and permanent elevations in blood pressure. The present study investigated whether changes in brain (i.e., hypothalamus) glycerophospholipid fatty acid profiles induced by a diet rich in omega 6 fatty acids and very low in alpha-linolenic acid (ALA) during pregnancy and the perinatal period could be reversed by subsequent feeding of a diet containing ALA. Female rats (6 per group) were mated and fed either a low ALA diet or a control diet containing ALA throughout pregnancy and until weaning of the pups at 3 weeks. At weaning, the pups (20 per group) remained on the diet of their mothers until 9 weeks, when half the pups were switched onto the other diet, thus generating four groups of animals. At 33 weeks, pups were killed, the hypothalamus dissected from the male rats and analysed for glycerophospholipid fatty acids. In the animals fed the diet with very little ALA and then re-fed the control diet containing high levels of ALA for 24 weeks, the DHA levels were still significantly less than the control values in PE, PS and PI fractions, by 9%, 18% and 34%, respectively. In this group, but not in the other dietary groups, ALA was detected in all glycerophospholipid classes at 0.2-1.7% of the total fatty acids. The results suggest that omega 6-3 PUFA imbalance early in life leads to irreversible changes in hypothalamic composition. The increased ALA and reduced DHA proportions in the animals re-fed ALA in later life are consistent with a dysfunction or down-regulation of the conversion of ALA to 18:4n-3 by the delta-6 desaturase.
Publisher: Springer Science and Business Media LLC
Date: 25-01-2022
DOI: 10.1186/S12909-022-03132-0
Abstract: The number of students enrolled in health courses at Australian universities is rising, increasing demand for clinical placements. Optometry students have historically undertaken clinical training in short-block rotations at university-led teaching clinics in metropolitan locations. This is changing, with some optometry programs adopting extended placements. These placements are conducted in community-based practices, with many incorporating a rural component to the training. This study explored factors which influence placement success and satisfaction from the perspective of optometry students. Nine focus groups were undertaken with 42 final year optometry students upon completion of a 26-week placement (of which at least half was undertaken in a non-metropolitan area, or area where a shortage of optometrists has been identified). Focus groups were audio recorded and transcribed verbatim. Thematic analysis was conducted according to Braun and Clarke’s 6 step method. Four key themes were identified during analysis. ‘Changing identity’, related to how the students grew both personally and professionally, with the extended placement being considered the vital component that allowed students to begin thinking of themselves as clinicians. The theme ‘Dealing with complex dynamics and circumstances’ predominantly described instances where the student-supervisor relationship was strained, resulting in high levels of anxiety made worse by a perceived lack of university support. ‘Optometrist under instruction’, related to students feeling that the placement was an ideal opportunity to trial the everyday reality of work without the obligation of an ongoing commitment or employment contract. Finally, the theme ‘Rural practice is more rewarding’, was about a chance to seek different experiences, meet new people and challenge themselves professionally. While the majority of students enjoyed their placement and felt that it was the key component of their training that equipped them for future practice, it is clear that universities and placement providers must provide both students and supervisors thorough and explicit guidance covering placement expectations. Furthermore, student support systems should be embedded into placement programs to ensure where issues arise, they are dealt with promptly and successfully. It is vital that ongoing professional development and pedagogical training for supervisors underpins continued accreditation.
Publisher: Wiley
Date: 14-10-2008
Publisher: Wiley
Date: 06-2001
DOI: 10.1046/J.1442-9071.2001.00402.X
Abstract: The contribution of rods and cones to the scotopic electroretinogram (ERG) of small animals is unclear, with a recent report suggesting that the mouse has no cone a-wave. The present study considered the contribution of cones to the ERG of the rat. Dark-adapted Long Evans rats (n = 4) had ERG signals collected following a single flash, which stimulated rods and cones (mixed response), or a twin-fash paradigm (short interstimulus interval, 1 s), which isolated cone responses. Rod signals were derived by digital subtraction of the cone signal from the mixed rod/cone ERG. The rat a-wave was found to be dominated by rod responses but cone responses contributed substantially (45%) to post-receptoral waveforms (b-wave) at higher light levels.
Publisher: Wiley
Date: 05-2005
Publisher: Elsevier BV
Date: 11-2001
Publisher: Public Library of Science (PLoS)
Date: 10-05-2016
Publisher: Informa UK Limited
Date: 06-11-2022
DOI: 10.1080/08164622.2022.2136514
Abstract: Access to culturally safe health services is a basic human right, however through the lasting effects of colonisation, oppression, and systemic racism, the in idual and community health of Indigenous peoples in Australia and Aotearoa New Zealand have been severely impacted. The Aboriginal and Torres Strait Islander Health and Cultural Safety Strategy of the Australian Health Practitioners Regulation Agency, and the Standards of Cultural Competence and Cultural Safety of the Optometrists and Dispensing Opticians Board of New Zealand, recognise the importance of access to safe health care for Aboriginal, Torres Strait Islander and Māori patients, which encompasses both clinical competency and cultural safety. Universities have an ongoing responsibility to ensure their learning and teaching activities result in graduates being able to provide culturally safe practice. This article highlights the emergence of culturally safe practices in the Australian and Aotearoa New Zealand optometry curricula over the last five years incorporating Indigenous ways of knowing, being and doing into the curricula, understanding the local Indigenous histories and contexts, the adoption of online cultural education modules, and clinical placement partnerships with local Indigenous communities. Whilst there is still much work to do to achieve the goal of graduating culturally safe optometrists, this paper focuses on features that enable or impede progress in the development of culturally safe practices within the optometry programmes to improve eye health equity for Indigenous recognise the ersity of Indigenous cultures across Australia and NZ.
Publisher: MDPI AG
Date: 15-03-2021
DOI: 10.3390/JCM10061215
Abstract: The aim of this study was to investigate the agreement between cycloplegic and non-cycloplegic autorefraction with an open-field auto refractor in a school vision screening set up, and to define a threshold for myopia that agrees with the standard cycloplegic refraction threshold. The study was conducted as part of the Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) study, which investigated the prevalence, incidence, and risk factors for myopia among children in South India. Children from two schools aged 5 to 15 years, with no ocular abnormalities and whose parents gave informed consent for cycloplegic refraction were included in the study. All the children underwent visual acuity assessment (Pocket Vision Screener, Elite school of Optometry, India), followed by non-cycloplegic and cycloplegic (1% tropicamide) open-field autorefraction (Grand Seiko, WAM-5500). A total of 387 children were included in the study, of whom 201 were boys. The mean (SD) age of the children was 12.2 (±2.1) years. Overall, the mean difference between cycloplegic and non-cycloplegic spherical equivalent (SE) open-field autorefraction measures was 0.34 D (limits of agreement (LOA), 1.06 D to −0.38 D). For myopes, the mean difference between cycloplegic and non-cycloplegic SE was 0.13 D (LOA, 0.63D to −0.36D). The prevalence of myopia was 12% (95% CI, 8% to 15%) using the threshold of cycloplegic SE ≤ −0.50 D, and was 14% (95% CI, 11% to 17%) with SE ≤ −0.50 D using non-cycloplegic refraction. When myopia was defined as SE of ≤−0.75 D under non-cycloplegic conditions, there was no difference between cycloplegic and non-cycloplegic open-field autorefraction prevalence estimates (12% 95% CI, 8% to 15% p = 1.00). Overall, non-cycloplegic refraction underestimates hyperopia and overestimates myopia but for subjects with myopia, this difference is minimal and not clinically significant. A threshold of SE ≤ −0.75 D agrees well for the estimation of myopia prevalence among children when using non-cycloplegic refraction and is comparable with the standard definition of cycloplegic myopic refraction of SE ≤ −0.50 D.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2016
DOI: 10.1161/HYPERTENSIONAHA.116.07461
Abstract: High fat diet (HFD)–induced hypertension in rabbits is neurogenic and caused by the central action of leptin, which is thought to be dependent on activation of α-melanocortin–stimulating hormone (α-MSH) and neuropeptide Y–positive neurons projecting to the dorsomedial hypothalamus (DMH) and ventromedial hypothalamus (VMH). However, leptin may act directly in these nuclei. Here, we assessed the contribution of leptin, α-MSH, and neuropeptide Y signaling in the DMH and VMH to diet-induced hypertension. Male New Zealand white rabbits were instrumented with a cannula for drug injections into the DMH or VMH and a renal sympathetic nerve activity (RSNA) electrode. After 3 weeks of an HFD (13.3% fat n=19), rabbits exhibited higher RSNA, mean arterial pressure (MAP), and heart rate compared with control diet–fed animals (4.2% fat n=15). Intra-VMH injections of a leptin receptor antagonist or SHU9119, a melanocortin 3/4 receptor antagonist, decreased MAP, heart rate, and RSNA compared with vehicle in HFD rabbits ( P .05) but not in control diet–fed animals. By contrast, α-MSH or neuropeptide Y injected into the VMH had no effect on MAP but produced sympathoexcitation in HFD rabbits ( P .05) but not in control diet–fed rabbits. The effects of the leptin antagonist, α-MSH, or neuropeptide Y injections into the DMH on MAP or RSNA of HFD rabbits were not different from those after vehicle injection. α-MSH into the DMH of control diet–fed animals did increase MAP, heart rate, and RSNA. We conclude that the VMH is the likely origin of leptin-mediated sympathoexcitation and α-MSH hypersensitivity that contribute to obesity-related hypertension.
Publisher: Wiley
Date: 05-2005
Publisher: Public Library of Science (PLoS)
Date: 13-03-2013
Publisher: Oxford University Press (OUP)
Date: 02-05-2014
DOI: 10.1093/NDT/GFU088
Publisher: Wiley
Date: 12-01-2022
DOI: 10.1111/OPO.12943
Abstract: To report the baseline prevalence of myopia among school children in Tamil Nadu, South India from a prospective cohort study. Children between the ages of 5 and 16 years from 11 schools in two districts of Tamil Nadu underwent vision screening. All children underwent visual acuity assessment using a Pocket Vision Screener followed by non-cycloplegic open-field autorefraction (Grand Seiko WAM-5500). Myopia was defined as a spherical equivalent (SE) refraction of ≤-0.75 D and high myopia was defined as SE ≤ -6.00 D. Distribution of refraction, biometry and factors associated with prevalence of myopia were the outcome measures. A total of 14,699 children completed vision screening, with 2% (357) of them having ocular abnormalities other than refractive errors or poor vision despite spectacle correction. The remaining 14,342 children (7557 boys 52.69%) had a mean age of 10.2 (Standard Deviation [SD] 2.8) years. A total of 2502 had myopia in at least one eye, a prevalence of 17.5% (95% CI: 14.7-20.5%), and 74 (0.5% 95% CI: 0.3-0.9%) had high myopia. Myopia prevalence increased with age (p < 0.001), but sex was not associated with myopia prevalence (p = 0.24). Mean axial length (AL 23.08 (SD = 0.91) mm) and mean anterior chamber depth (ACD 3.45 (SD = 0.27) mm) positively correlated with age (p < 0.001). The mean flat (K1 43.37 (SD = 1.49) D) and steep (K2 44.50 (SD = 1.58) D) corneal curvatures showed negative correlation with age (p = 0.02 and p < 0.001, respectively). In the multivariable logistic regression, older age and urban school location had higher odds for prevalence of myopia. The baseline prevalence of myopia among 5- to 16-year-old children in South India is larger than that found in previous studies, indicating that myopia is becoming a major public health problem in this country.
Publisher: Springer Science and Business Media LLC
Date: 12-08-2015
Publisher: Informa UK Limited
Date: 28-05-2015
DOI: 10.3109/07420528.2015.1032414
Abstract: Meal-fed conscious rabbits normally exhibit postprandial elevation in blood pressure, heart rate (HR) and locomotor activity, which is abolished by consumption of a high-fat diet (HFD). Here, we assessed whether the cardiovascular changes are attributable to the increased caloric intake due to greater fat content or to hyperphagia. Rabbits were meal-fed during the baseline period then maintained on either an ad libitum normal fat diet (NFD) or ad libitum HFD for 2 weeks. Blood pressure, HR and locomotor activity were measured daily by radio-telemetry alongside food intake and body weight. Caloric intake in rabbits given a NFD ad libitum rose 50% from baseline but there were no changes in cardiovascular parameters. By contrast, HR increased by 10% on the first day of the ad libitum HFD (p < 0.001) prior to any change in body weight while blood pressure increased 7% after 4 d (p < 0.01) and remained elevated. Baseline 24-h patterns of blood pressure and HR were closely associated with mealtime, characterised by afternoon peaks and morning troughs. When the NFD was changed from meal-fed to ad libitum, blood pressure and HR did not change but afternoon activity levels decreased (p < 0.05). By contrast, after 13 d ad libitum HFD, morning HR, blood pressure and activity increased by 20%, 8% and 71%, respectively. Increased caloric intake specifically from fat, but not as a result of hyperphagia, appears to directly modulate cardiovascular homeostasis and circadian patterns, independent of white adipose tissue accumulation.
Publisher: KARGER
Date: 2008
DOI: 10.1159/000115355
Abstract: Obesity and its sequelae may prove to be the greatest threat to human lifestyle and health in the developed world this century. The so called obesity epidemic has seen the incidence of obesity and overweight almost double in Western societies and the trend is mirrored in nations that are transitioning to first world economies. There is no doubt that much of the rise in obesity can be attributed to lifestyle factors such as the excess consumption of energy-dense foods and the decline in physical activity. However, the 'fetal origins'hypothesis, first proposed by Barker and colleagues and elaborated by several groups over the past 15 years to be termed the 'Developmental Origins of Adult Health and Disease' (DOHaD), provides an alternative explanation for the rising rates of obesity. The DOHaD hypothesis states that exposure to an unfavourable environment during development (either in utero or in the early postnatal period) programmes changes in fetal or neonatal development such that the in idual is then at greater risk of developing adulthood disease. This chapter discusses the effects of maternal obesity on fetal development and birth outcomes as well as the manner in which DOHaD may contribute to the obesity epidemic.
Publisher: Wiley
Date: 04-2003
DOI: 10.1007/S11745-003-1084-Y
Abstract: Hypertension is a major risk factor for cardiovascular and cerebrovascular disease. Previous work in both animals and humans with high blood pressure has demonstrated the antihypertensive effects of n-3 polyunsaturated fatty acids (PUFA), although it is not known whether these nutrients are effective in preventing hypertension. The predominant n-3 PUFA in the mammalian nervous system, docosahexaenoic acid (DHA), is deposited into synaptic membranes at a high rate during the perinatal period, and recent observations indicate that the perinatal environment is important for the normal development of blood pressure control. This study investigated the importance of perinatal n-3 PUFA supply in the control of blood pressure in adult Sprague-Dawley rats. Pregnant rat dams were fed semisynthetic diets that were either deficient in (DEF) or supplemented with (CON) n-3 PUFA. Offspring were fed the same diets as their mothers until 9 wk then, half of the rats from each group were crossed over to the opposite diet creating four groups, i.e., CON-CON CON-DEF DEF-DEF, DEF-CON. Mean arterial blood pressures (MAP) were measured directly, at 33 wk of age, by cannulation of the femoral artery. The phospholipid fatty acid profile of the hypothalamic region was determined by capillary gas-liquid chromatography. The tissue phospholipid fatty acid profile reflected the diet that the rats were consuming at the time of testing. Both groups receiving DEF after 9 wk of age (i.e., DEF-DEF and CON-DEF) had similar profiles with a reduction in DHA levels of 30%, compared with rats receiving CON (i.e., CON-CON and DEF-CON). DEF-DEF rats had significantly raised MAP compared with all other groups, with differences as great as 17 mm Hg. DEF-CON rats had raised MAP compared with CON-CON rats, and DEF-DEF rats had higher MAP than CON-DEF rats, despite the fact that their respective fatty acid profiles were not different. These findings indicate that inadequate levels of DHA in the perinatal period are associated with altered blood pressure control in later life. The way in which these long-term effects are produced remains to be elucidated.
Publisher: Elsevier
Date: 2022
Publisher: SAGE Publications
Date: 25-11-2022
DOI: 10.1177/02692163221135349
Abstract: Early indications were of a major decline in specialist palliative care volunteer numbers during COVID-19. It is important that ongoing deployment and role of volunteers is understood, given the dependence of many palliative care services on volunteers for quality care provision. To understand the roles and deployment of volunteers in specialist palliative care services as they have adjusted to the impact of COVID-19. Observational multi-national study, using a cross-sectional online survey with closed and free-text option questions. Disseminated via social media, palliative care networks and key collaborators from May to July 2021. Any specialist palliative care setting in any country, including hospices, day hospices, hospital based or community teams. The person responsible for managing the deployment of volunteers was invited to complete the survey. Valid responses were received from 304 organisations (35 countries, 80.3% Europe). Most cared for adults only (60.9%), provided in-patient care (62.2%) and were non-profit (62.5%). 47.0% had cared for people with COVID-19. 47.7% changed the way they deployed volunteers the mean number of active volunteers dropped from 203 per organisation to 33, and 70.7% reported a decrease in volunteers in direct patient/family facing roles. There was a shift to younger volunteers. 50.6% said this drop impacted care provision, increasing staff workload and pressure, decreasing patient support, and increasing patient isolation and loneliness. The sustained reduction in volunteer deployment has impacted the provision of specialist palliative care. Urgent consideration must be given to the future of volunteering including virtual modes of delivery, micro-volunteering, and appealing to a younger demographic.
Publisher: Canadian Science Publishing
Date: 06-2013
Abstract: Over the past 100 years, advances in pharmaceutical and medical technology have reduced the burden of communicable disease, and our appreciation of the mechanisms underlying the development of noncommunicable disease has broadened. During this time, a number of studies, both in humans and animal models, have highlighted the importance of maintaining an optimal diet during pregnancy. In particular, a number of studies support the hypothesis that suboptimal maternal protein and fat intake during pregnancy can have long-term effects on the growing fetus, and increase the likelihood of these offspring developing cardiovascular, renal, or metabolic diseases in adulthood. More recently, it has been shown that dietary intake of a number of micronutrients may offset or reverse the deleterious effects of macronutrient imbalance. Furthermore, maternal fat intake has also been identified as a major contributor to a healthy fetal environment, with a beneficial role for unsaturated fats during development as well as a beneficial impact on cell membrane physiology. Together these studies indicate that attempts to optimise maternal nutrition may prove to be an efficient and cost-effective strategy for preventing the development of cardiovascular, renal, or metabolic diseases.
Publisher: Wiley
Date: 26-11-2004
Publisher: Elsevier BV
Date: 03-2014
Abstract: Children of obese mothers have increased risk of metabolic syndrome as adults. Here we report the effects of a high-fat diet in the absence of maternal obesity at conception on skeletal muscle metabolic and transcriptional profiles of adult male offspring. Female Sprague Dawley rats were fed a diet rich in saturated fat and sucrose [high-fat diet (HFD): 23.5% total fat, 9.83% saturated fat, 20% sucrose wt:wt] or a normal control diet [(CD) 7% total fat, 0.5% saturated fat, 10% sucrose wt:wt] for the 3 wk prior to mating and throughout pregnancy and lactation. Maternal weights were not different at conception however, HFD-fed dams were 22% heavier than controls during pregnancy. On a normal diet, the male offspring of HFD-fed dams were not heavier than controls but demonstrated features of insulin resistance, including elevated plasma insulin concentration [40.1 ± 2.5 (CD) vs 56.2 ± 6.1 (HFD) mU/L P = 0.023]. Next-generation mRNA sequencing was used to identify differentially expressed genes in the offspring soleus muscle, and gene set enrichment analysis (GSEA) was used to detect coordinated changes that are characteristic of a biological function. GSEA identified 15 upregulated pathways, including cytokine signaling (P < 0.005), starch and sucrose metabolism (P < 0.017), inflammatory response (P < 0.024), and cytokine-cytokine receptor interaction (P < 0.037). A further 8 pathways were downregulated, including oxidative phosphorylation (P < 0.004), mitochondrial matrix (P < 0.006), and electron transport/uncoupling (P < 0.022). Phosphorylation of the insulin signaling protein kinase B was reduced [2.86 ± 0.63 (CD) vs 1.02 ± 0.27 (HFD) P = 0.027] and mitochondrial complexes I, II, and V protein were downregulated by 50-68% (P < 0.005). On a normal diet, the male offspring of HFD-fed dams did not become obese adults but developed insulin resistance, with transcriptional evidence of muscle cytokine activation, inflammation, and mitochondrial dysfunction. These data indicate that maternal overnutrition, even in the absence of prepregnancy obesity, can promote metabolic dysregulation and predispose offspring to type 2 diabetes.
Publisher: Wiley
Date: 06-10-2022
DOI: 10.1111/JHN.12949
Publisher: Springer Science and Business Media LLC
Date: 22-11-2022
DOI: 10.3758/S13428-022-02023-Y
Abstract: Remote view eye-tracking systems are prone to errors when used on spectacle wearers due to reflections from the lenses and frame that result in inaccurate tracking. Traditionally, these trackers are situated below a computer monitor and the viewer's eye moments are recorded while they view the screen. Reflections may be influenced by the pantoscopic tilt of the spectacles, whereby the tilt angle causes incident light to be reflected to the camera. To overcome this problem, we propose mounting the tracker above the monitor to avoid these reflections and test the accuracy and precision of subjects with single vision spectacles, multifocals, and no correction, using both mounting positions. Experimental results showed that this alternate position had overall worse accuracy (4.06° ± 0.13) and precision (0.67° ± 0.05) compared to the standard configuration (2.15° ± 0.06 vs. 0.50° ± 0.03), with more invalid readings (5.91 vs. 19.19%) for single vision lens wearers. Multifocals performed better for the top-mounting position for the top portion of the monitor, suggesting higher-order aberrations from the bottom portion of the lens negatively impact data quality. Higher pantoscopic tilt angles displayed an improved accuracy for this alternate position (r
Publisher: Wiley
Date: 06-2009
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.NUMECD.2018.02.019
Abstract: Maternal high fat diets (mHFD) have been associated with an increased offspring cardiovascular risk. Recently we found that the class IIa HDAC-MEF2 pathway regulates gene programs controlling fatty acid oxidation in striated muscle. This same pathway controls hypertrophic responses in the heart. We hypothesized that mHFD is associated with activation of signal controlling class II a HDAC activity and activation of genes involved in fatty acid oxidation and cardiac hypertrophy in offspring. Female Sprague Dawley rats were fed either normal fat diet (12%) or high fat diet (43%) three weeks prior to mating, remaining on diets until study completion. Hearts of postnatal day 1 (PN1) and PN10 pups were collected. Bioenergetics and respiration analyses were performed in neonatal ventricular cardiomyocytes (NVCM). In offspring exposed to mHFD, body weight was increased at PN10 accompanied by increased body fat percentage and blood glucose. Heart weight and heart weight to body weight ratio were increased at PN1 and PN10, and were associated with elevated signalling through the AMPK-class IIa HDAC-MEF2 axis. The expression of the MEF2-regulated hypertrophic markers ANP and BNP were increased as were expression of genes involved in fatty acid oxidation. However this was only accompanied by an increased protein expression of fatty acid oxidation enzymes at PN10. NVCM isolated from these pups exhibited increased glycolysis and an impaired substrate flexibility. Combined, these results suggest that mHFD induces signalling and transcriptional events indicative of reprogrammed cardiac metabolism and of cardiac hypertrophy in Sprague Dawley rat offspring.
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.BIOCEL.2011.12.011
Abstract: Globally 30% of adults are overweight or obese. The white adipocyte is a major component of adipose tissue, and as the obesity epidemic increases it is critically important to understand the factors determining adipocyte development and function. Adipogenesis has two distinct phases determination of the adipocyte from a multipotent stem cell, and terminal differentiation of a pre-adipocyte into a mature adipocyte. The environment encountered in early life can alter adipocyte number and size and potentially impact upon adipocyte endocrine function in adulthood. These alterations may contribute to the pathophysiology of chronic diseases and thus targeted therapy of the adipocyte has great potential for treating the current obesity epidemic.
Publisher: Wiley
Date: 12-04-2007
DOI: 10.1113/EXPPHYSIOL.2006.036202
Abstract: We have previously reported that male and female offspring of Sprague-Dawley rats fed a diet rich (approximately 50% of caloric intake from fat) in animal fat (lard) during pregnancy and suckling (OHF) demonstrate cardiovascular dysfunction, including blunted endothelium-dependent vasodilatation in the aorta as well as reduced renal Na(+),K(+)-ATPase activity. Cardiovascular dysfunction has been reported in other models of developmental programming and some researchers describe transmission from F(1) to F(2) generations. Here we report a study of vascular function, as assessed in isolated rings of aorta mounted in an organ bath, and renal Na(+),K(+)-ATPase activity in 6-month-old male and female F(2) offspring of lard-fed and control-fed (OC) dams (n = 13 per diet group). An increase in brain (OC 0.61 +/- 0.01% versus OHF 0.66 +/- 0.02% of bodyweight) and kidney weights (OC 0.32 +/- 0.01% versus OHF 0.37 +/- 0.01% of bodyweight) was observed in female F(2) offspring of lard-fed dams compared with F(2) controls (P < 0.03). Constrictor responses to phenylephrine in the aorta were not different from F(2) controls (repeated measures ANOVA, P = 0.85). Also, endothelium-dependent dilator function, as assessed by responses to acetylcholine (repeated measures ANOVA, P = 0.96) and passive distensibility in the absence of extracellular calcium (repeated measures ANOVA, P = 0.68), was similar. Additionally, renal Na(+),K(+)-ATPase activity was not statistically different from that observed in control animals (ANOVA, P = 0.89). Although a maternal diet rich in animal fat has deleterious effects on parameters of cardiovascular risk in F(1) animals, it does not appear that disorders previously reported in the F(1) generation are transmitted to the F(2) generation.
Publisher: Cambridge University Press (CUP)
Date: 2013
DOI: 10.1017/JNS.2013.36
Abstract: The high fat content in Western diets probably affects placental function during pregnancy with potential consequences for the offspring in the short and long term. The aim of the present study was to compare genome-wide placental gene expression between rat dams fed a high-fat diet (HFD) and those fed a control diet for 3 weeks before conception and during gestation. Gene expression was measured by microarray and pathway analysis was performed. Gene expression differences were replicated by real-time PCR and protein expression was assessed by Western blot analysis. Placental and fetal weights at E17.25 were not altered by exposure to the maternal HFD. Gene pathways targeting placental growth, blood supply and chemokine signalling were up-regulated in the placentae of dams fed the HFD. The up-regulation in messenger RNA expression for five genes Ptgs2 (fatty acid cyclo-oxidase 2 COX2), Limk1 (LIM domain kinase 1), Pla2g2a (phospholipase A2), Itga1 (integrin α-1) and Serpine1 was confirmed by real-time PCR. Placental protein expression for COX2 and LIMK was also increased in HFD-fed dams. In conclusion, maternal HFD feeding alters placental gene expression patterns of placental growth and blood supply and specifically increases the expression of genes involved in arachidonic acid and PG metabolism. These changes indicate a placental response to the altered maternal metabolic environment.
Publisher: Springer Science and Business Media LLC
Date: 03-2003
DOI: 10.1007/S00125-003-1042-7
Abstract: We consider the nature of retinal dysfunction in streptozotocin rats and assess the functional benefits of administering an angiotensin enzyme inhibitor or an inhibitor of advanced glycation end product formation. Sprague-Dawley rats (n=44) were randomly assigned to control (C=12, C(p)=4, C(a)=4) and diabetic groups (Streptozotocin, D=24). Diabetes was diagnosed based on a range of physiological and biochemical parameters at 4, 8 and 12 weeks. Streptozotocin animals were administered insulin daily (4 units protophane). Animals were treated with either an Angiotensin Converting Enzyme inhibitor (perindopril, C(p)=4, D(p)=8) or an inhibitor of advanced glycation end product formation (aminoguanidine, C(a)=4, D(a)=8). Dark-adapted electroretinograms were measured on anaesthetized animals at 12 weeks following streptozotocin treatment. Photoreceptoral and inner retinal responses were extracted, modelled and compared using ANOVA. Streptozotocin injection increased blood glucose, glycosylated haemoglobin, fluid intake and urine volume, whereas body weight was decreased. Perindopril treatment produced improvements (p<0.05) in all indices, whereas aminoguanidine therapy produced some improvement in blood glucose and water intake. Streptozotocin rats showed losses of photoreceptoral-P3 (-27%), postreceptoral-P2 (-15%) and oscillatory potential (-19%) litudes of a similar magnitude. Perindopril therapy returned photoreceptoral and inner retinal function to within control limits. However, aminoguanidine treatment gave no significant functional improvement. Our findings provide evidence for a selective neuropathy in diabetes with a primary photoreceptoral lesion. Treatment with perindopril, an angiotensin converting enzyme inhibitor, ameliorates the neuropathy.
Publisher: Cambridge University Press (CUP)
Date: 29-09-2020
Publisher: Elsevier BV
Date: 09-2014
Publisher: Wiley
Date: 05-1998
DOI: 10.1111/J.1442-9071.1998.TB01378.X
Abstract: Two morphological cone variants are identified in keratoconus nipple and oval. The present study was designed to assess the impact of aetiological factors on cone morphology. As part of a prospective controlled study, keratoconic subjects from a suburban practice (n = 89) underwent videokeratograph examination and completed a questionnaire detailing aetiological factors. Comparison of 95% confidence limits (CL bootstrap method) for apical power between the two cone morphology groups showed no statistical significance. Oval cones were located at a greater eccentricity than nipple cones, as their definitions suggest. Associations between aetiological factors examined and the morphology of the cone were not significant (bootstrapped 95% CL). Despite the suggestion of morphological variants in keratoconus, the results of the present study suggest a common cone aetiology.
Publisher: Frontiers Media SA
Date: 24-06-2021
DOI: 10.3389/FPHYS.2021.693157
Abstract: Maternal high-fat diet in rabbits leads to hypertension and elevated renal sympathetic nerve activity (RSNA) in adult offspring but whether this is due to adiposity or maternal programming is unclear. We gave intracerebroventricular (ICV) and ventromedial hypothalamus (VMH) administration of leptin-receptor antagonist, α-melanocyte-stimulating hormone (αMSH), melanocortin-receptor antagonist (SHU9119), or insulin-receptor (InsR) antagonist to conscious adult offspring from mothers fed a high-fat diet (mHFD), control diet (mCD), or mCD offspring fed HFD for 10d (mCD10d, to deposit equivalent fat but not during development). mHFD and mCD10d rabbits had higher mean arterial pressure (MAP, +6.4 mmHg, +12.1 mmHg, p & 0.001) and RSNA (+2.3 nu, +3.2 nu, p & 0.01) than mCD, but all had similar plasma leptin. VMH leptin-receptor antagonist reduced MAP (−8.0 ± 3.0 mmHg, p & 0.001) in mCD10d but not in mHFD or mCD group. Intracerebroventricular leptin-receptor antagonist reduced MAP only in mHFD rabbits ( p & 0.05). Intracerebroventricular SHU9119 reduced MAP and RSNA in mHFD but only reduced MAP in the mCD10d group. VMH αMSH increased RSNA (+85%, p & 0.001) in mHFD rabbits but ICV αMSH increased RSNA in both mHFD and mCD10d rabbits (+45%, +51%, respectively, p & 0.001). The InsR antagonist had no effect by either route on MAP or RSNA. Hypothalamic leptin receptor and brain-derived neurotrophic factor ( BDNF ) mRNA were greater in mHFD compared with mCD rabbits and mCD10d rabbits. In conclusion, the higher MAP in mHFD and mCD10d offspring was likely due to greater central leptin signaling at distinct sites within the hypothalamus while enhanced melanocortin contribution was common to both groups suggesting that residual body fat was mainly responsible. However, the effects of SHU9119 and αMSH on RSNA pathways only in mHFD suggest a maternal HFD may program sympatho-excitatory capacity in these offspring and that this may involve increased leptin receptor and BDNF expression.
Publisher: Cambridge University Press (CUP)
Date: 17-01-2023
DOI: 10.1017/S2040174422000666
Abstract: Maternal protein restriction is often associated with structural and functional sequelae in offspring, particularly affecting growth and renal-cardiovascular function. However, there is little understanding as to whether hypertension and kidney disease occur because of a primary nephron deficit or whether controlling postnatal growth can result in normal renal-cardiovascular phenotypes. To investigate this, female Sprague-Dawley rats were fed either a low-protein (LP, 8.4% protein) or normal-protein (NP, 19.4% protein) diet prior to mating and until offspring were weaned at postnatal day (PN) 21. Offspring were then fed a non ‘growth’ (4.6% fat) which ensured that catch-up growth did not occur. Offspring growth was determined by weight and dual energy X-ray absorptiometry. Nephron number was determined at PN21 using the disector-fractionator method. Kidney function was measured at PN180 and PN360 using clearance methods. Blood pressure was measured at PN360 using radio-telemetry. Body weight was similar at PN1, but by PN21 LP offspring were 39% smaller than controls (P diet 0.001). This difference was due to proportional changes in lean muscle, fat, and bone content. LP offspring remained smaller than NP offspring until PN360. In LP offspring, nephron number was 26% less in males and 17% less in females, than NP controls (P diet 0.0004). Kidney function was similar across dietary groups and sexes at PN180 and PN360. Blood pressure was similar in LP and NP offspring at PN360. These findings suggest that remaining on a slow growth trajectory after exposure to a suboptimal intrauterine environment does not lead to the development of kidney dysfunction and hypertension.
Publisher: MDPI AG
Date: 12-03-2015
DOI: 10.3390/NU7031881
Publisher: Wiley
Date: 20-12-2015
DOI: 10.1111/OPO.12174
Abstract: To assess ocular blood flow responses to acute IOP stress following 4 weeks of chronic IOP elevation in streptozotocin (STZ)-induced diabetic and control rats. We hypothesise that chronic IOP elevation for 4 weeks will further impair blood flow regulation in STZ-induced diabetic rats eyes. Two weeks following citrate buffer or STZ-injections chronic IOP elevation was induced in Long Evans rats via fortnightly intracameral injections of microspheres (15 μm) suspended in 5% polyethylene glycol. IOP was monitored daily. Electroretinography (ERG, -6.79-2.07 log cd s m(-2) ) was undertaken at Week 4 to compare photoreceptor (RmPIII ), ON-bipolar cell (Vmax ) and ganglion cell dominant ERG [scotopic threshold response (STR)] components. 4 weeks post-chronic IOP induction, ocular blood flow (laser Doppler flowmetry) was measured in response to acute IOP challenge (10-100 mmHg, in 5 mmHg steps, each 3 min). Four weeks of chronic IOP (mean ± S.E.M., citrate: 24.0 ± 0.3 to 30.7 ± 1.3 and STZ-diabetes: 24.2 ± 0.2 to 31.1 ± 1.2 mmHg) was associated with reduced photoreceptor litude in both groups (-25.3 ± 2.2% and -17.2 ± 3.0%, respectively). STZ-diabetic eyes showed reduced photoreceptor sensitivity (citrate: 0.5 ± 1.8%, STZ-diabetic: -8.1 ± 2.4%). Paradoxically ON-bipolar cell sensitivity was increased, particularly in citrate control eyes (citrate: 166.8 ± 25.9%, STZ-diabetic: 64.8 ± 18.7%). The ganglion cell dominant STR was not significantly reduced in STZ-diabetic rats. Using acute IOP elevation to probe autoregulation, we show that STZ-diabetes impaired autoregulation compared with citrate control animals. The combination of STZ-diabetes and chronic IOP elevation further impaired autoregulation. STZ-diabetes and chronic IOP elevation appear to be additive risk factors for impairment of ocular blood flow autoregulation.
Publisher: Springer Science and Business Media LLC
Date: 09-12-2022
DOI: 10.1186/S12909-022-03918-2
Abstract: In Australia, optometry students have traditionally undertaken their clinical training in short-block rotations at University-led teaching clinics in metropolitan locations. Demand for clinical placements is growing as the number of optometry students steadily increases. As such, universities and clinical education providers must look for more erse methods of student placement. Extended clinical placements in community-based settings are one alternative: a model similar to the longitudinal clerkships in medicine. This study aimed to explore the experience of extended clinical placements from the perspective of the optometrists who supervised students. It also sought to determine whether there were differences in views between metropolitan and rural practitioners. This mixed methods study included a survey and interviews with optometrists who had previously supervised Deakin University optometry students on an extended 26-week (2 x 13-weeks) clinical placement. Lines of enquiry focused on the benefits and challenges associated with extended placements areas for improvement duration of the placement and willingness to supervise further students. Interviews were transcribed verbatim and analysed using Braun and Clarke’s 6 step method of thematic analysis with a qualitative descriptive approach. Supervisors felt that hosting a student prompted greater reflective practice and critical appraisal of clinical decisions. The extended nature of the placement was thought to foster greater immersion in the clinical setting and community for the students and establish a stronger relationship between supervisor and student. Supervisors recognised the importance of role-modelling and mentoring the next generation of optometrists however noted that taking on a student was a sizeable commitment. Willingness to host a student was not dependent on the supervisor’s location (rural vs metropolitan) p = 0.57. However, interviews uncovered motivations that were unique to supervisors residing in rural locations, such as succession planning. Overall, supervisors were positive about the value of student extended clinical placement in optometry and felt that it was a fulfilling and professionally beneficial experience. Lack of time and financial remuneration were the key downsides highlighted. Schools of optometry might carefully consider engaging in discussion about the duration of such placements, but 26 weeks was considered appropriate by supervisors.
Publisher: Springer Science and Business Media LLC
Date: 30-11-2022
DOI: 10.1186/S12909-022-03912-8
Abstract: Virtual simulations are used throughout healthcare training programs to enable development of clinical skills, however the potential for virtual simulation to enhance cognitive and affective skills is less well understood. This study explored pre-clinical optometry students’ perceptions of the impact of virtual simulation on the development of core competency skills including patient-centred care, communication, scientific literacy, and evidence-based practice. A mixed methods study was conducted using pre-existing anonymized data from an electronic survey distributed to pre-clinical optometry students enrolled in the double degree Bachelor of Vision Science/Master of Optometry at Deakin University, Australia. The data were interpreted using descriptive statistics and qualitative analysis using constant comparison for thematic analysis. A total of 51 responses were analyzed. Students reported that virtual simulation motivated them to become an optometrist (93%) and to learn beyond the course material (77%). Students reported that after participating in the virtual simulation, their core competency skills improved: patient-centered care (100%) evidence-based practice (93%) and clinical reasoning (93%). The themes identified through qualitative analysis were: enablers to cognitive experience in virtual simulation in optometry education, realism of the virtual simulation design, dimensions of fidelity in virtual simulations design replicated the complexity of the optometric environment, virtual simulation as an enabler for learning and assessment in optometry education, a place to develop cognitive and affective skills and application of learning in the virtual simulation developed an appreciation of future roles and professional identity. Optometry students perceived virtual simulation in optometric education as a valuable training and assessment strategy enabled by qualities that generate contextual, cognitive, functional, task and psychological fidelity. The data provide insight to inform how optometry educators can incorporate simulation into the curriculum.
Publisher: Springer Science and Business Media LLC
Date: 14-02-2013
DOI: 10.1038/HR.2013.2
Abstract: In rabbits, mean arterial pressure (MAP) increases in response to fat feeding, but does not increase further with progressive weight gain. We documented the progression of adiposity and the alterations in endocrine/cardiovascular function in response to fat feeding in rabbits, to determine whether stabilization of MAP after 3 weeks could be explained by stabilization of neurohormonal factors. Rabbits were fed a control diet or high-fat diet for 9 weeks (n=23). Fat feeding progressively increased body mass and adiposity. Heart rate (HR) was elevated by week 3 (15±3%) but changed little thereafter. The effects of fat feeding on MAP were dependent on baseline MAP and peaked at 3 weeks. From baseline, MAP 80 mm Hg, MAP had increased by 8.1±1.3, 4.7±1.7 and 5.6±1.2 mm Hg, respectively, 3, 6 and 9 weeks after commencing the high-fat diet, but by only 2.6±1.5, 3.0±1.7 and 3.9±1.4 mm Hg, respectively, in control rabbits. Fat feeding did not increase MAP from a baseline >80 mm Hg. Plasma concentrations of leptin and insulin increased during the first 3-6 weeks of fat feeding and then stabilized (increasing by 111±17% and 731±302% by week 9, respectively), coinciding with the pattern of changes in MAP and HR. Plasma total cholesterol, triglycerides, renin activity, aldosterone and atrial natriuretic peptide were not significantly altered by fat feeding. Given that the changes in plasma leptin and insulin mirrored the changes in MAP and HR, leptin and insulin may be important factors in the development of hypertension and tachycardia in the rabbit model of obesity.
Publisher: Springer Science and Business Media LLC
Date: 24-11-2013
DOI: 10.1007/S00417-012-2212-4
Abstract: We consider whether pre-existing streptozotocin induced hyperglycemia in rats affects the ability of the eye to cope with a single episode of acute intraocular pressure (IOP) elevation. Electroretinogram (ERG) responses were measured (-6.08 to 1.92 log cd.s.m(-2)) in anaesthetized (60:5 mg/kg ketamine:xylazine) dark-adapted (>12 h) adult Sprague-Dawley rats 1 week after a single acute IOP elevation to 70 mmHg for 60 min. This was undertaken in rats treated 11 weeks earlier with streptozotocin (STZ, n = 12, 50 mg/kg at 6 weeks of age) or citrate buffer (n = 12). ERG responses were analyzed to derive an index of photoreceptor (a-wave), ON-bipolar (b-wave), amacrine (oscillatory potentials) and inner retinal (positive scotopic threshold response, pSTR) function. One week following acute IOP elevation there was a significant reduction of the ganglion cell pSTR (-35 ± 11 %, P = 0.0161) in STZ-injected animals. In contrast the pSTR in citrate-injected animals was not significant changed (+16 ± 14 %). The negative component of the STR was unaffected by IOP elevation in either citrate or STZ-treated groups. Photoreceptoral (a-wave, citrate-control +4 ± 3 %, STZ +4 ± 5 %) and ON-bipolar cell (b-wave, control +4 ± 3 %, STZ +4 ± 5 %) mediated responses were not significantly affected by IOP elevation in either citrate- or STZ-injected rats. Finally, oscillatory potentials (citrate-control +8 ± 23 %, STZ +1 ± 17 %) were not reduced 1 week after IOP challenge. The ganglion cell dominated pSTR was reduced following a single episode of IOP elevation in STZ diabetic, but not control rats. These data indicate that hyperglycemia renders the inner retina more susceptible to IOP elevation.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2014
DOI: 10.1161/HYPERTENSIONAHA.113.02498
Abstract: Exposure to maternal obesity or a maternal diet rich in fat during development may have adverse outcomes in offspring, such as the development of obesity and hypertension. The present study examined the effect of a maternal high-fat diet (m-HFD) on offspring blood pressure and renal sympathetic nerve activity, responses to stress, and sensitivity to central administration of leptin and ghrelin. Offspring of New Zealand white rabbits fed a 13% HFD were slightly heavier than offspring from mothers fed a 4% maternal normal fat diet ( P .05) but had 64% greater fat pad mass ( P =0.015). Mean arterial pressure, heart rate, and renal sympathetic nerve activity at 4 months of age were 7%, 7%, and 24% greater, respectively ( P .001), in m-HFD compared with maternal normal fat diet rabbits, and the renal sympathetic nerve activity response to airjet stress was enhanced in the m-HFD group. m-HFD offspring had markedly elevated pressor and renal sympathetic nerve activity responses to intracerebroventricular leptin (5–100 µg) and enhanced sympathetic responses to intracerebroventricular ghrelin (1–5 nmol). In contrast, there was resistance to the anorexic effects of intracerebroventricular leptin and less neuronal activation as detected by Fos immunohistochemistry in the arcuate (−57% P .001) and paraventricular (−37% P .05) nuclei of the hypothalamus in m-HFD offspring compared with maternal normal fat diet rabbits. We conclude that offspring from mothers consuming an HFD exhibit an adverse cardiovascular profile in adulthood because of altered central hypothalamic sensitivity to leptin and ghrelin.
Publisher: Cambridge University Press (CUP)
Date: 13-11-2021
DOI: 10.1017/S2040174420001014
Abstract: Nutrition during the periconceptional period influences postnatal cardiovascular health. We determined whether in vitro embryo culture and transfer, which are manipulations of the nutritional environment during the periconceptional period, dysregulate postnatal blood pressure and blood pressure regulatory mechanisms. Embryos were either transferred to an intermediate recipient ewe (ET) or cultured in vitro in the absence (IVC) or presence of human serum (IVCHS) and a methyl donor (IVCHS+M) for 6 days. Basal blood pressure was recorded at 19–20 weeks after birth. Mean arterial pressure (MAP) and heart rate (HR) were measured before and after varying doses of phenylephrine (PE). mRNA expression of signaling molecules involved in blood pressure regulation was measured in the renal artery. Basal MAP did not differ between groups. Baroreflex sensitivity, set point, and upper plateau were also maintained in all groups after PE stimulation. Adrenergic receptors alpha-1A (αAR1A), alpha-1B (αAR1B), and angiotensin II receptor type 1 (AT1R) mRNA expression were not different from controls in the renal artery. These results suggest there is no programmed effect of ET or IVC on basal blood pressure or the baroreflex control mechanisms in adolescence, but future studies are required to determine the impact of ET and IVC on these mechanisms later in the life course when developmental programming effects may be unmasked by age.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2012
DOI: 10.1161/HYPERTENSIONAHA.112.201251
Abstract: Infiltration of macrophages into the artery wall plays detrimental roles during hypertension by promoting vascular inflammation and endothelial dysfunction, and it occurs via a chemo-attractant action of chemokines on macrophage cytokine receptors. We sought to identify the key chemokine receptors associated with macrophage infiltration into the vascular wall during deoxycorticosterone acetate (DOCA)/salt-induced hypertension in mice and to evaluate the impact of pharmacological inhibition of these receptors on blood pressure and leukocyte accumulation. Mice treated with DOCA/salt for 21 days displayed markedly elevated systolic blood pressure (158±2 versus 114±5 mm Hg in sham group P .0001). Polymerase chain reaction screening via a gene array of 20 chemokine receptors indicated an increased expression of CCR2 in aortas of DOCA/salt-treated mice. Real-time polymerase chain reaction confirmed mRNA upregulation of CCR2 in aortas from DOCA/salt-treated animals and of the CCR2 ligands CCL2, CCL7, CCL8, and CCL12 (all -fold versus sham P .05). Flow cytometry revealed 2.9-fold higher macrophage numbers (ie, CD45 + CD11b + F4/80 + cells) in the aortic wall of DOCA/salt versus sham-treated mice. Intervention with a CCR2 antagonist, INCB3344 (30 mg/kg per day, IP), 10 days after the induction of hypertension with DOCA/salt treatment, reduced the aortic expression of CCR2 mRNA and completely reversed the DOCA/salt-induced influx of macrophages. Importantly, INCB3344 substantially reduced the elevated blood pressure in DOCA/salt-treated mice. Hence, our findings highlight CCR2 as a promising therapeutic target to reduce both macrophage accumulation in the vascular wall and blood pressure in hypertension.
Publisher: American Physiological Society
Date: 06-2011
DOI: 10.1152/AJPRENAL.00055.2011
Abstract: Low glomerular (nephron) endowment has been associated with an increased risk of cardiovascular and renal disease in adulthood. Nephron endowment in humans is determined by 36 wk of gestation, while in rats and mice nephrogenesis ends several days after birth. Specific genes and environmental perturbations have been shown to regulate nephron endowment. Until now, design-based method for estimating nephron number in developing kidneys was unavailable. This was due in part to the difficulty associated with unambiguously identifying developing glomeruli in histological sections. Here, we describe a method that uses lectin histochemistry to identify developing glomeruli and the physical disector/fractionator principle to provide unbiased estimates of total glomerular number ( N glom ). We have characterized N glom throughout development in kidneys from 76 rats and model this development with a 5-parameter logistic equation to predict N glom from embryonic day 17.25 to adulthood ( r 2 = 0.98). This approach represents the first design-based method with which to estimate N glom in the developing kidney.
Publisher: International Union of Crystallography (IUCr)
Date: 09-2012
Publisher: Wiley
Date: 17-02-2006
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-12-2022
DOI: 10.1097/OPX.0000000000001975
Abstract: In this comprehensive assessment of environmental associations with refractive status among schoolchildren in India, outdoor time was the key modifiable risk factor associated with myopia rather than time spent on near work. This study aimed to investigate the environmental risk factors associated with myopia among adolescent schoolchildren in South India. Children in grades 8 to 10 from 11 schools in Tamil Nadu, South India, underwent eye examination and risk factor assessments through a modified version of the Sydney myopia questionnaire. Time spent on near work and outdoors was analyzed after ision into three groups based on tertiles. Mixed-effects logistic regression was performed to assess the factors associated with myopia. A total of 3429 children (response rate, 78.4%) provided both questionnaire and refraction data. The mean (standard deviation) age was 14 (0.93) years with an equal distribution of sexes. Myopia was present among 867 children (noncycloplegic spherical equivalent refraction, ≤−0.75 D). Refraction was not associated with near work tertiles ( P = .22), whereas less time outdoors was associated with higher myopic refractions ( P = .01). Refraction shifted toward increased myopia with an increase in the near-work/outdoor time ratio ( P = .005). Children living in apartment housing had a higher prevalence of myopia compared with other types of housing ( P .001). In multivariate analysis, increased time outdoors was a protective factor against myopia (odds ratio, 0.79 95% confidence interval, 0.63 to 0.99 P = .04), whereas living in apartment housing (odds ratio, 1.27 95% confidence interval, 1.04 to 1.55 P = .02) was a significant risk factor. In this cohort of Indian children, outdoor time, increased near-work/outdoor time ratio, and type of housing were the factors associated with myopia. Policies should target implementing a balance between near-work and outdoor time among children.
Publisher: Wiley
Date: 08-11-2018
DOI: 10.1002/ASE.1840
Abstract: Understanding orbital anatomy is important for optometry students, but the learning resources available are often fragile, expensive, and accessible only during scheduled classes. Drawing on a constructivist, personalized approach to learning, this study investigated students' perceptions of an alternative learning resource: a three-dimensional (3D) printed model used in an active learning task. A human skull was three-dimensionally scanned and used to produce a 3D printed model for each student. Students actively participated in model creation by tracing suture lines and coloring in idual orbital bones during a practical class, then keeping the model for future study. Students' perceptions of the 3D orbital model were examined through a questionnaire: the impact the model had on their learning perceptions of the 3D orbit compared to traditional resources and utility of having their own personalized model. The 3D orbit was well received by the student cohort. Participants (n = 69) preferred the 3D orbit as a resource for learning orbital bone anatomy compared to traditional learning resources, believing the model helped them to understand and visualize the spatial relationships of the bones, and that it increased their confidence to apply this knowledge. Overall, the participants liked that they co-created the model, could touch and feel it, and that they had access to it whenever they liked. Three-dimensional printing technology has the potential to enable the creation of effective learning resources that are robust, low-cost and readily accessible to students, and should be considered by anyone wishing to incorporate personalized resources to their multimodal teaching repertoire.
Publisher: Frontiers Media SA
Date: 02-11-2017
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2016
Publisher: American Physiological Society
Date: 09-2021
DOI: 10.1152/AJPRENAL.00029.2021
Abstract: The present study shows, for the first time, that low birth weight as a result of maternal nutrition is associated with low podocyte endowment. However, a mild podocyte deficit at birth did not result in glomerular pathology in adulthood. In contrast, postnatal podocyte loss in combination with excessive body weight led to albuminuria and glomerulosclerosis. Taken together, these findings provide new insights into the associations between birth weight, podocyte indexes, postnatal weight, and glomerular pathology.
Publisher: Frontiers Media SA
Date: 02-12-2014
Publisher: Springer Science and Business Media LLC
Date: 22-09-2021
DOI: 10.1038/S41366-021-00969-1
Abstract: Early postnatal overfeeding (PO) induces long-term overweight and reduces brown adipose tissue (BAT) thermogenesis. Exercise has been suggested as a possible intervention to increase BAT function. In this study, we investigated chronical effects of moderate-intensity exercise in BAT function in postnatal overfed male Wistar rats METHODS: Litters' delivery was on postnatal-day 0 - PN0. At PN2, litters were adjusted to nine (normal litter - NL) or three pups (small litter - SL) per dam. Animals were weaned on PN21 and in PN30 randomly ided into sedentary (NL-Sed and SL-Sed) or exercised (NL-Exe and SL-Exe), N of 14 litters per group. Exercise protocol started (PN30) with an effort test training sessions were performed three times weekly at 60% of the VO Moderate exercise chronically increased BAT thermogenesis in both, NL and SL groups. In NL-Exe by increasing Sympathetic activity, and in SL-Exe by a combination of increased β3-AR and UCP1 content with morphologic remodeling of BAT. Chronically increasing BAT thermogenesis in obese subjects may lead to higher overall energy expenditure, favoring the reduction of obesity and related comorbidities.
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/850471
Abstract: Mammalian placentation is a vital facet of the development of a healthy and viable offspring. Throughout gestation the placenta changes to accommodate, provide for, and meet the demands of a growing fetus. Gestational gene expression is a crucial part of placenta development. The endocannabinoid pathway is activated in the placenta and decidual tissues throughout pregnancy and aberrant endocannabinoid signaling during the period of placental development has been associated with pregnancy disorders. In this study, the gene expression of eight endocannabinoid system enzymes was investigated throughout gestation. Rat placentae were obtained at E14.25, E15.25, E17.25, and E20, RNA was extracted, and microarray was performed. Gene expression of enzymes Faah, Mgll, Plcd4, Pld1, Nat1, Dagl α , and Ptgs2 was studied (cohort 1, microarray). Biological replication of the results was performed by qPCR (cohort 2). Four genes showed differential expression ( Mgll, Plcd4, Ptgs2, and Pld1 ), from mid to late gestation. Genes positively associated with gestational age were Ptgs2, Mgll, and Pld1 , while Plcd4 was downregulated. This is the first comprehensive study that has investigated endocannabinoid pathway gene expression during rat pregnancy. This study provides the framework for future studies that investigate the role of endocannabinoid system during pregnancy.
Publisher: Informa UK Limited
Date: 11-2019
DOI: 10.1111/CXO.12873
Abstract: People living in rural and remote areas have poorer ocular health outcomes compared with those living in metropolitan areas. Reasons for this are multiple and complex but access to care is consistently reported as a defining factor. The geographic maldistribution of eye-care professionals is a major obstacle for regional, rural and remote Australians seeking care. Research from the medical profession suggests adopting the 'rural pipeline' concept to address the issue of maldistribution. This approach appears to have had some success in medicine, and involves recruiting students from a rural background, exposing students to rural practice through placements and offering graduates incentives and support to practice rurally. Lessons could be learnt from the medical field as there is a dearth of literature describing the utilisation of the rural pipeline in allied health. However, given the differences between professions it cannot be assumed factors and results will be the same. A greater understanding is required to determine whether optometry is a profession which may benefit from the rural pipeline concept.
Publisher: American Physiological Society
Date: 06-2014
DOI: 10.1152/AJPRENAL.00092.2014
Abstract: Nephron number ( N glom ) and size (V glom ) are correlated with risk for chronic cardiovascular and kidney disease and may be predictive of renal allograft viability. Unfortunately, there are no techniques to assess N glom and V glom in intact kidneys. This work demonstrates the use of cationized ferritin (CF) as a magnetic resonance imaging (MRI) contrast agent to measure N glom and V glom in viable human kidneys donated to science. The kidneys were obtained from patients with varying levels of cardiovascular and renal disease. CF was intravenously injected into three viable human kidneys. A fourth control kidney was perfused with saline. After fixation, immunofluorescence and electron microscopy confirmed binding of CF to the glomerulus. The intact kidneys were imaged with three-dimensional MRI and CF-labeled glomeruli appeared as punctate spots. Custom software identified, counted, and measured the apparent volumes of CF-labeled glomeruli, with an ∼6% false positive rate. These measurements were comparable to stereological estimates. The MRI-based technique yielded a novel whole kidney distribution of glomerular volumes. Histopathology demonstrated that the distribution of CF-labeled glomeruli may be predictive of glomerular and vascular disease. Variations in CF distribution were quantified using image texture analyses, which be a useful marker of glomerular sclerosis. This is the first report of direct measurement of glomerular number and volume in intact human kidneys.
Publisher: Public Library of Science (PLoS)
Date: 16-02-2012
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 04-11-2014
Abstract: To consider the effect of chronic arterial hypertension on the susceptibility of the retina to acute IOP challenge. Anesthetized adult Long-Evans rats with normal (n = 5, receiving saline subcutaneously), chronic high blood pressure (BP) for 4 weeks (n = 15, Angiotensin II subcutaneously), and acute high BP for 1 hour (n = 10, Angiotensin II intravenously) underwent IOP elevation (10-120 mm Hg, 5 mm Hg steps each 3 minutes). During IOP elevation, retinal function and ocular blood flow were monitored with electroretinogram (ERG) and laser-Doppler flowmetry (LDF), respectively. Blood pressure was monitored via a femoral artery cannula. Electroretinogram and LDF responses are expressed as a percentage of baseline and compared between groups. The left ventricle and the aorta were dissected to assess the morphologic changes associated with chronic hypertension. Four weeks of hypertension (systolic BP 192 ± 4 mm Hg) produced cardiac hypertrophy and thickened aortic arterial walls compared with controls (systolic BP 112 ± 3 mm Hg). Retinal function was unaltered with chronic hypertension compared with normotensive animals. During acute IOP elevation, ERG and LDF were reduced in a dose-dependent manner in all BP groups. Both chronic and acute hypertension made the ERG and LDF less susceptible to IOP elevation. However, the degree of resistance to IOP elevation was greater in acute hypertension compared with chronic hypertension (P < 0.05). Acute BP elevation makes retinal function and blood flow less susceptible to IOP elevation. The reduced susceptibility afforded by improved ocular perfusion pressure is compromised after 4 weeks of chronic hypertension.
Publisher: Springer Science and Business Media LLC
Date: 02-2017
Abstract: The placenta plays an important role during pregnancy providing maternal blood supply from the uterus to the developing fetus. The structure and function of the placenta changes with gestation, as the fetus develops and its demands change. This study aims to elucidate changes in cytokine and chemokine gene expression throughout mid-to-late gestation in rat placenta. Sprague Dawley rats were time-mated, and placentae were obtained from 6 pregnant dams at 4 different gestational periods: E14.25, E15.25, E17.25, and E20. Changes in placental gene expression were measured by microarray analysis. Differentially expressed inflammatory genes were functionally categorized by pathway analysis. To validate the microarray results, a subset of genes was analyzed by quantitative real-time polymerase chain reaction (qPCR) in a validation cohort of 22 rats. Changes in messenger RNA (mRNA) expression of various cytokines, chemokines, and genes of the tumor growth factor β and tumor necrosis factor family were analyzed in rat placentae at E14.25, E15.25, E17.25, and E20. Forty-six genes were differentially expressed, and of these 21 genes had increased expression in late gestation (E20). The gestational age pattern of gene expression was confirmed by qPCR in the validation cohort. The observed acute, prelabor changes in the expression of these genes during gestation warrant further investigation to elucidate their role in pregnancy and parturition.
Publisher: Wiley
Date: 30-08-2019
DOI: 10.1002/EDM2.91
Publisher: Public Library of Science (PLoS)
Date: 14-12-2017
Publisher: Informa UK Limited
Date: 03-2011
DOI: 10.1111/J.1444-0938.2010.00564.X
Abstract: Although intraocular pressure (IOP) remains an important risk factor for glaucoma, it is clear that other factors can also influence disease development and progression. More recently, the role that blood pressure (BP) has in the genesis of glaucoma has attracted attention, as it represents a clinically modifiable risk factor and thus provides the potential for new treatment strategies beyond IOP reduction. The interplay between blood pressure and IOP determines the ocular perfusion pressure (OPP), which regulates blood flow to the optic nerve. If OPP is a more important determinant of ganglion cell injury than IOP, then hypotension should exacerbate the detrimental effects of IOP elevation, whereas hypertension should provide protection against IOP elevation. Epidemiological evidence provides some conflicting outcomes of the role of systemic hypertension in the development and progression of glaucoma. The most recent study showed that patients at both extremes of the blood pressure spectrum show an increased prevalence of glaucoma. Those with low blood pressure would have low OPP and thus reduced blood flow however, that people with hypertension also show increased risk is more difficult to reconcile. This finding may reflect an inherent blood flow dysregulation secondary to chronic hypertension that would render retinal blood flow less able to resist changes in ocular perfusion pressure. Here we review both clinical and experimental studies that have attempted to clarify the relationships among blood pressure, OPP and blood flow autoregulation in the pathogenesis of glaucoma.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2010
DOI: 10.1161/HYPERTENSIONAHA.109.141119
Abstract: The activation of the sympathetic nervous system through the central actions of the adipokine leptin has been suggested as a major mechanism by which obesity contributes to the development of hypertension. However, direct evidence for elevated sympathetic activity in obesity has been limited to muscle. The present study examined the renal sympathetic nerve activity and cardiovascular effects of a high-fat diet (HFD), as well as the changes in the sensitivity to intracerebroventricular leptin. New Zealand white rabbits fed a 13.5% HFD for 4 weeks showed modest weight gain but a 2- to 3-fold greater accumulation of visceral fat compared with control rabbits. Mean arterial pressure, heart rate, and plasma norepinephrine concentration increased by 8%, 26%, and 87%, respectively ( P .05), after 3 weeks of HFD. Renal sympathetic nerve activity was 48% higher ( P .05) in HFD compared with control diet rabbits and was correlated to plasma leptin ( r =0.87 P .01). Intracerebroventricular leptin administration (5 to 100 μg) increased mean arterial pressure similarly in both groups, but renal sympathetic nerve activity increased more in HFD-fed rabbits. By contrast, intracerebroventricular leptin produced less neurons expressing c-Fos in HFD compared with control rabbits in regions important for appetite and sympathetic actions of leptin (arcuate: −54%, paraventricular: −69%, and dorsomedial hypothalamus: −65%). These results suggest that visceral fat accumulation through consumption of a HFD leads to marked sympathetic activation, which is related to increased responsiveness to central sympathoexcitatory effects of leptin. The paradoxical reduction in hypothalamic neuronal activation by leptin suggests a marked “selective leptin resistance” in these animals.
Publisher: Informa UK Limited
Date: 20-05-2013
DOI: 10.3109/07420528.2013.784771
Abstract: Consumption of a high-fat diet (HFD) by rabbits results in increased blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA) within 1 wk. Here, we determined how early this activation occurred and whether it was related to changes in cardiovascular and neural 24-h rhythms. Rabbits were meal-fed a HFD for 3 wks, then a normal-fat diet (NFD) for 1 wk. BP, HR, and RSNA were measured daily in the home cage via implanted telemeters. Baseline BP, HR, and RSNA over 24 h were 71 ± 1 mm Hg, 205 ± 4 beats/min and 7 ± 1 normalized units (nu). The 24-h pattern was entrained to the feeding cycle and values increased from preprandial minimum to postprandial maximum by 4 ± 1 mm Hg, 51 ± 6 beats/min, and 1.6 ± .6 nu each day. Feeding of a HFD markedly diminished the preprandial dip after 2 d (79-125% of control p < 0.05) and this reduction lasted for 3 wks of HFD. Twenty-four-hour BP, HR, and RSNA concurrently increased by 2%, 18%, and 22%, respectively. Loss of preprandial dipping accounted for all of the BP increase and 50% of the RSNA increase over 3 wks and the 24-h rhythm became entrained to the light-dark cycle. Resumption of a NFD did not alter the BP preprandial dip. Thus, elevated BP induced by a HFD and mediated by increased sympathetic nerve activity results from a reduction in preprandial dipping, from the first day. Increased calories, glucose, insulin, and leptin may account for early changes, whereas long-term loss of dipping may be related to increased sensitivity of sympathetic pathways.
Publisher: Wiley
Date: 08-2002
DOI: 10.1007/S11745-002-0958-3
Abstract: A previous study conducted in guinea pigs suggested that ingestion of diets high in EPA and DHA may result in suboptimal retinal function. The aim of the present study was to evaluate retinal function in pigmented (Long-Evans) rats, raised to a third generation on diets that were either deficient in n-3 PUFA or adequate (with the addition of DHA). Electroretinographic assessment employed full-field white flash stimulation. Photoreceptor responses were evaluated in terms of peak litudes and implicit times (a-wave, b-wave), intensity-response functions (Naka-Rushton), and the parameters of a model of transduction (P3). Retinal phospholipid FA composition was measured by capillary GLC. DHA levels were reduced by 55% in n-3-deficient animals compared with the n-3-adequate group, whereas the levels of docosapentaenoic acid n-6 were 44 times higher in n-3-deficient animals. The level of arachidonic acid was marginally higher (12.8%) in n-6-adequate animals. The n-3-deficient animals exhibited significantly reduced retinal sensitivity (sigma and S values were both affected by 0.29 log units) and increased b-wave implicit times compared with those fed the n-3-adequate diet. These data suggest that n-3 PUFA are required for development of retinal sensitivity, more so than other indices of retinal function assessed by current methods, such as maximal response litude. However, the benefit for retinal function of adding preformed DHA to diets already replete in n-3 PUFA remains unclear.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2012
DOI: 10.1161/HYPERTENSIONAHA.111.190413
Abstract: Hypertension and elevated sympathetic drive result from consumption of a high-calorie diet and deposition of abdominal fat, but the etiology and temporal characteristics are unknown. Rabbits instrumented for telemetric recording of arterial pressure and renal sympathetic nerve activity (RSNA) were fed a high-fat diet for 3 weeks then control diet for 1 week or control diet for 4 weeks. Baroreflexes and responses to air-jet stress and hypoxia were determined weekly. After 1 week of high-fat diet, caloric intake increased by 62%, accompanied by elevated body weight, blood glucose, plasma insulin, and leptin (8%, 14%, 134%, and 252%, respectively). Mean arterial pressure, heart rate, and RSNA also increased after 1 week (6%, 11%, and 57%, respectively). Whereas mean arterial pressure and body weight continued to rise over 3 weeks of high-fat diet, heart rate and RSNA did not change further. The RSNA baroreflex was attenuated from the first week of the diet. Excitatory responses to air-jet stress diminished over 3 weeks of high-fat diet, but responses to hypoxia were invariant. Resumption of a normal diet returned glucose, insulin, leptin, and heart rate to control levels, but body weight, mean arterial pressure, and RSNA remained elevated. In conclusion, elevated sympathetic drive and impaired baroreflex function, which occur within 1 week of consumption of a high-fat, high-calorie diet, appear integral to the rapid development of obesity-related hypertension. Increased plasma leptin and insulin may contribute to the initiation of hypertension but are not required for maintenance of mean arterial pressure, which likely lies in alterations in the response of neurons in the hypothalamus.
Publisher: Springer Science and Business Media LLC
Date: 11-07-2022
DOI: 10.1186/S12909-022-03493-6
Abstract: Diagnostic reasoning is an essential skill for optometry practice and a vital part of the curriculum for optometry trainees but there is limited understanding of how diagnostic reasoning is performed in optometry or how this skill is best developed. A validated and reliable self-reflective inventory for diagnostic reasoning in optometry, would enable trainees and registered practitioners to benchmark their diagnostic reasoning skills, identify areas of strength and areas for improvement. A 41 item self-reflective inventory, the Diagnostic Thinking Inventory, used extensively in the medical field was adapted for use in optometry and called the Diagnostic Thinking Inventory for Optometry (DTI-O). The inventory measures two subdomains of diagnostic reasoning, flexibility in thinking and structured memory. Context based changes were made to the original inventory and assessed for face and content validity by a panel of experts. The inventory was administered to two groups, experienced (qualified) optometrists and second-year optometry students to establish validity and reliability of the self-reflective tool in optometry. Exploratory Factor Analysis uncovered 13 domain specific items were measuring a single construct, diagnostic reasoning. One misfitting item was removed following Rasch analysis. Two unidimensional subdomains were confirmed in the remaining 12 items: Flexibility in Thinking (χ2 = 12.98, P = 0.37) and Structured Memory (χ2 = 8.74, P = 0.72). The ‘Diagnostic Thinking Inventory for Optometry Short’ (DTI-OS) tool was formed from these items with the total and subdomain scores exhibiting strong internal reliability Total score C α = 0.92. External reliability was established by test-retest methodology (ICC 0.92, 95% CI 0.83–0.96, P .001) and stacked Rasch analysis (one-way ANOVA, F = 0.07, P = 0.80). Qualified optometrists scored significantly higher ( P .001) than students, demonstrating construct validity. This study showed that the DTI-O and DTI-OS are valid and reliable self-reflective inventories to quantify diagnostic reasoning ability in optometry. With no other validated tool to measure this metacognitive skill underpinning diagnostic reasoning a self-reflective inventory could support the development of diagnostic reasoning in practitioners and guide curriculum design in optometry education.
Publisher: Wiley
Date: 10-07-2012
DOI: 10.1113/EXPPHYSIOL.2012.064972
Abstract: Methodological improvements in measuring cardiovascular parameters have meant that data can be collected from freely moving animals in their home cage. However, experiments in rabbits still often require them to be restrained in a laboratory setting. The aim of this study was to determine whether measurements collected when rabbits were placed in a holding box in the laboratory are representative of values obtained in freely moving conscious rabbits. Nine New Zealand White rabbits received two radiotelemetry implants to monitor mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). The MAP measured in the laboratory (71 ± 1 mmHg) was similar to that in the home cage (69 ± 1 mmHg), but there was less MAP variability. The RSNA was also similar in both environments. In contrast, laboratory heart rate (HR) was 7% lower than home cage HR (181 ± 4 beats min(-1), P < 0.001), but HR variability was similar. Baroreflex gain, assessed by spectral analysis, was 19% higher in the laboratory than in the home cage due to lower MAP mid-frequency variability in the laboratory. Home cage circadian patterns of MAP and HR were strongly influenced by feeding and activity. Nevertheless, MAP and RSNA laboratory measurements were the same as average 24 h values and remained similar over several weeks. We conclude that while HR is generally lower in the laboratory, a valid representation of MAP and RSNA can be given by laboratory measurements.
Publisher: Elsevier BV
Date: 07-2014
Publisher: Cambridge University Press
Date: 20-04-2006
Publisher: Wiley
Date: 21-06-2020
DOI: 10.1002/AR.24417
Publisher: Springer Science and Business Media LLC
Date: 03-2001
DOI: 10.1038/85354
Publisher: Springer Science and Business Media LLC
Date: 10-04-2020
DOI: 10.1038/S41598-020-62956-2
Abstract: Optical coherence tomography angiography (OCTA) is widely used in ophthalmic practice. Most OCTA studies based their findings on a single OCTA measurement. We conducted an observational study of 82 eyes from 82 healthy subjects to compare variations of OCTA parameters among five successive measurements. A 3 × 3 mm Early Treatment of Diabetic Retinopathy Study grid centred at fovea was used. An average from five successive OCTA measurements (both perfusion density and vessel density) was calculated to be used as the reference standard. There was no significant difference in perfusion and vessel densities among five successive OCTA measurements, and from different levels of averaging. Perfusion density was close to the reference standard when average from three measurements was used (discrepancy within 1.5%) as compared with using just one measurement (discrepancy from 3.2% to 4.5%). Vessel density was also close to reference standard when average from three measurements was used (within 0.8 mm −1 ) as compared with using just one measurement (2 mm −1 ). Software feature that allows OCTA devices to average quantitative parameters for analysis will be useful.
Publisher: Public Library of Science (PLoS)
Date: 22-08-2016
Publisher: Frontiers Media SA
Date: 28-04-2022
DOI: 10.3389/FPHYS.2022.840179
Abstract: Perturbations to nutrition during critical periods are associated with changes in embryonic, fetal or postnatal developmental patterns that may render the offspring more likely to develop cardiovascular disease in later life. The aim of this study was to evaluate whether autonomic nervous system imbalance underpins in the long-term hypertension induced by dietary protein restriction during peri-pubertal period. Male Wistar rats were assigned to groups fed with a low protein (4% protein, LP) or control diet (20.5% protein NP) during peri-puberty, from post-natal day (PN) 30 until PN60, and then all were returned to a normal protein diet until evaluation of cardiovascular and autonomic function at PN120. LP rats showed long-term increased mean arterial pressure ( p = 0.002) and sympathetic arousal increased power of the low frequency (LF) band of the arterial pressure spectral ( p = 0.080) compared with NP animals. The depressor response to the ganglion blocker hexamethonium was increased in LP compared with control animals ( p = 0.006). Pulse interval variability showed an increase in the LF band and LF/HF ratio ( p = 0.062 and p = 0.048) in LP animals. The cardiac response to atenolol and/or methylatropine and the baroreflex sensitivity were similar between groups. LP animals showed ventricular hypertrophy ( p = 0.044) and increased interstitial fibrosis ( p = 0.028) compared with controls. Reduced protein carbonyls (PC) ( p = 0.030) and catalase activity ( p = 0.001) were observed in hearts from LP animals compared with control. In the brainstem, the levels of PC ( p = 0.002) and the activity of superoxide dismutase and catalase ( p = 0.044 and p = 0.012) were reduced in LP animals, while the levels of GSH and total glutathione were higher ( p = 0.039 and p = 0.038) compared with NP animals. Protein restriction during peri-pubertal period leads to hypertension later in life accompanied by sustained sympathetic arousal, which may be associated with a disorganization of brain and cardiac redox state and structural cardiac alteration.
Publisher: Humana Press
Date: 2012
DOI: 10.1007/978-1-61779-851-1_10
Abstract: Design-based stereology is considered the gold-standard method for estimating the total number of glomeruli, and thereby nephrons, in the adult kidney. However, until recently, a design-based method for estimating nephron number in the developing kidney was not available. For such a method to provide accurate and precise estimates, unambiguous identification of developing nephrons is essential. Here, we describe a combined histochemical/stereological technique for estimating total nephron number in the developing mouse and rat kidney. The method can be modified for use in other species.
Publisher: American Physiological Society
Date: 06-2009
DOI: 10.1152/AJPREGU.90931.2008
Abstract: We tested whether mild adiposity alters responsiveness of the kidney to activation of the renal sympathetic nerves. After rabbits were fed a high-fat or control diet for 9 wk, responses to reflex activation of renal sympathetic nerve activity (RSNA) with hypoxia and electrical stimulation of the renal nerves (RNS) were examined under pentobarbital anesthesia. Fat pad mass and body weight were, respectively, 74% and 6% greater in fat-fed rabbits than controls. RNS produced frequency-dependent reductions in renal blood flow, cortical and medullary perfusion, glomerular filtration rate, urine flow, and sodium excretion and increased renal plasma renin activity (PRA) overflow. Responses of sodium excretion and medullary perfusion were significantly enhanced by fat feeding. For ex le, 1 Hz RNS reduced sodium excretion by 79 ± 4% in fat-fed rabbits and 46 ± 13% in controls. RNS (2 Hz) reduced medullary perfusion by 38 ± 11% in fat-fed rabbits and 9 ± 4% in controls. Hypoxia doubled RSNA, increased renal PRA overflow and medullary perfusion, and reduced urine flow and sodium excretion, without significantly altering mean arterial pressure (MAP) or cortical perfusion. These effects were indistinguishable in fat-fed and control rabbits. Neither MAP nor PRA were significantly greater in conscious fat-fed than control rabbits. These observations suggest that mild excess adiposity can augment the antinatriuretic response to renal nerve activation by RNS, possibly through altered neural control of medullary perfusion. Thus, sodium retention in obesity might be driven not only by increased RSNA, but also by increased responsiveness of the kidney to RSNA.
Publisher: Wiley
Date: 03-05-2016
DOI: 10.1002/DMRR.2805
Abstract: Animal studies report a nephron deficit in offspring exposed to maternal diabetes, yet are limited to models of severe hyperglycaemia which do not reflect the typical clinical condition and which are associated with foetal growth restriction that may confound nephron endowment. We aimed to assess renal morphology and function in offspring of leptin receptor deficient mice (Lepr Nephron endowment was assessed in offspring of C57BKS/J Lepr Compared with +/+ dams, Lepr IGT throughout gestation resulted in a nephron deficit that was established early in renal development. Maternal IGT was associated with glomerular hypertrophy in adult offspring, likely a compensatory response to maintain normal renal function. Given the increasing prevalence of IGT, monitoring glucose from early in gestation may be important to prevent altered kidney morphology. Copyright © 2016 John Wiley & Sons, Ltd.
Publisher: Frontiers Media SA
Date: 12-03-2019
Publisher: Elsevier BV
Date: 04-2021
Publisher: MDPI AG
Date: 06-08-2020
DOI: 10.3390/JCM9082539
Abstract: Mechanical tissue stresses are important contributors to the increased risk of sight-threatening pathology in larger, more myopic eyes. The contribution of altered ocular vasculature to the development of this pathology is less well defined. The current study investigated the impact of eye size on the superficial vasculature of the macula. Subjects (n = 104) aged 18–50, with no history of ocular or vascular disease, or myopia control, were recruited from university staff and student populations in Australia and Hong Kong. Refractive error, ocular size, retinal morphology and vascular morphology were quantified through open field autorefraction, ocular biometry and ocular coherence tomography angiography. Morphology of the superficial retinal capillary plexus was assessed over a 3 × 3 mm fovea-centred area. Perfusion area and vessel length densities were analysed relative to axial eye length and retinal thickness. A significant inverse association was found between axial length and vascular density measures (perfusion area density r2 = 0.186, p 0.001 and vessel length density r2 = 0.102, p = 0.001). Perfusion area and vessel length densities were reduced by 5.8% (p = 0.001) in the longest, relative to the shortest, eyes. The aggregated ganglion cell layer inner plexiform layer thickness was also inversely associated with eye size (r2 = 0.083, p = 0.003), and reduced, by 8.1% (p 0.001), in the longest eyes. An inverse association of eye size and superficial retinal vasculature density, that is not simply explained by retinal expansion or image magnification factors, was confirmed. These data support the hypothesis that ongoing metabolic challenges may underlie the development of myopia-related and -associated pathology in larger eyes.
Publisher: Informa UK Limited
Date: 20-04-2023
Publisher: Elsevier BV
Date: 12-2010
DOI: 10.1016/J.APPET.2010.07.006
Abstract: We examined the effect of ω-3 polyunsaturated fatty acid (PUFA) deficiency during development on sodium appetite. Being raised on an ω-3 PUFA deficient diet increased the intake of 0.5M NaCl following furosemide-induced sodium depletion by 40%. This occurred regardless of the diet they were maintained on later in life, and the increased consumption persisted for 3 days. In a second study, animals were administered furosemide and low-dose captopril. Sodium consumption of deficient raised animals was again higher than that of the control raised. Fos immunoreactivity in brain areas associated with sodium appetite and excretion were not influenced by diet. Our findings indicate that inadequate dietary ω-3 PUFA during development results in an exaggerated sodium appetite later in life.
Publisher: Springer Science and Business Media LLC
Date: 10-2011
Publisher: Wiley
Date: 28-08-2012
DOI: 10.1111/J.1440-1681.2011.05579.X
Abstract: 1. In the past 30 years the prevalence of obesity and overweight have doubled. It is now estimated that globally over 500 million adults are obese and a further billion adults are overweight. Obesity is a cardiovascular risk factor and some studies suggest that up to 70% of cases of essential hypertension may be attributable, in part, to obesity. Increasingly, evidence supports a view that obesity-related hypertension may be driven by altered hypothalamic signalling, which results in inappropriately high appetite and sympathetic nerve activity to the kidney. 2. In addition to the adult risk factors for obesity and hypertension, the environment encountered in early life may 'programme' the development of obesity, hypertension and cardiovascular disease. In particular, maternal obesity or high dietary fat intake in pregnancy may induce changes in fetal growth trajectories and predispose in iduals to develop obesity and related sequelae. 3. The mechanisms underlying the programming of obesity-related hypertension are becoming better understood. However, several issues require clarification, particularly with regard to the role of the placenta in transferring fatty acid to the fetal compartment, the impact of placental inflammation and cytokine production in obesity. 4. By understanding which factors are most associated with the development of obesity and hypertension in the offspring, we can focus therapeutic and behavioural interventions to most efficiently reduce the intergenerational propagation of the obesity cycle.
Publisher: Bentham Science Publishers Ltd.
Date: 08-2012
DOI: 10.2174/138920112802502060
Abstract: We present four case studies of the literature discussing the effects of physical forces on biological function. While the field of biomechanics has existed for many decades, it may be considered by some a poor cousin to biochemistry and other traditional fields of medical research. In these case studies, including cardiovascular and respiratory systems, we demonstrate that, in fact, many systems historically believed to be controlled by biochemistry are dominated by biomechanics. We discuss both the previous paradigms that have advanced research in these fields and the changing paradigms that will define the progressions of these fields for decades to come. In the case of biomechanical effects of flowing blood on the endothelium, this has been well understood for decades. In the cases of platelet activation and liquid clearance from the lungs during birth, these discoveries are far more recent and perhaps not as universally accepted. While only a few specific ex les are examined here, it is clear that not enough attention is paid to the possible mechanical links to biological function. The continued development of these research areas, with the inclusion of physical effects, will hopefully provide new insight into disease development, progression, diagnosis and effective therapies.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-09-2021
DOI: 10.1097/OPX.0000000000001799
Abstract: Optometric educators are constantly looking for learning and teaching approaches to improve clinical skills training. In addition, the COVID-19 pandemic has made educators scrutinize the time allocated to face-to-face teaching and practice. Simulation learning is an option, but its use must first be evaluated against traditional learning methods. The purpose of this study was to compare the training of binocular indirect ophthalmoscopy skills achieved by students and optometrists through deliberate practice on the Eyesi Indirect Ophthalmoscope simulator with deliberate practice using a peer. Students and optometrists were randomly allocated to practice on either the simulator or a peer. Binocular indirect ophthalmoscopy performance was assessed using a peer and the simulator as the patients at different time points. Knowledge and confidence were examined before and following all practice sessions using a quiz and survey. Significant improvements in binocular indirect ophthalmoscopy performance using either a peer or the simulator as the patient for assessment were seen after 8 hours of student practice ( P .001) and after a half-hour practice time for optometrists ( P .001). There was no significant difference in performance overall between those practicing on a simulator and those practicing on a peer ( P .05). Confidence in ability to perform the technique was lower for students who had practiced on the simulator. The simulator has similar efficacy to peer practice for teaching binocular indirect ophthalmoscopy to students and maintenance of this clinical skill for optometrists. Simulation does not replace the need for peer practice but may be a useful adjunct reducing the face-to-face hours required. These findings present a need for further research regarding erse applications of the Eyesi Indirect Ophthalmoscope simulator in the curriculum for training optometry students and as a continuing professional development offering for optometrists, given the short exposure duration required to observe a significant improvement in skill.
Publisher: Springer Science and Business Media LLC
Date: 26-04-2016
DOI: 10.1007/S12020-016-0965-Y
Abstract: Maternal obesity programmes a range of metabolic disturbances for the offspring later in life. Moreover, environmental changes during the suckling period can influence offspring development. Because both periods significantly affect long-term metabolism, we aimed to study whether cross-fostering during the lactation period was sufficient to rescue a programmed obese phenotype in offspring induced by maternal obesity following monosodium L-glutamate (MSG) treatment. Obesity was induced in female Wistar rats by administering subcutaneous MSG (4 mg/g body weight) for the first 5 days of postnatal life. Control and obese female rats were mated in adulthood. The resultant pups were ided into control second generation (F
Publisher: Oxford University Press (OUP)
Date: 09-10-2012
DOI: 10.1093/NDT/GFR539
Publisher: Informa UK Limited
Date: 09-2001
DOI: 10.1111/J.1444-0938.2001.TB05037.X
Abstract: BACKGROUND: The retinal response to flickering stimuli (steady state ERG) recruits many retinal elements and is a sensitive indicator of early retinal dysfunction. This study reports the post-natal maturation of the steady state ERG response in guinea pigs. METHODS: The steady state ERG response to flickering stimuli (0.6 to 20 Hz) was recorded from dark adapted (more than 12 hrs) English Shorthair guinea pigs (n = 7) using flashes that produced rod and cone dominated responses. Temporal sensitivity functions and critical fusion frequencies (CFF) were derived over a range of ages from postnatal day (PND) 1 to 45. RESULTS: Guinea pig rod and cone temporal sensitivity functions show shape characteristics and CFF similar to humans. Furthermore, the post-natal development of the guinea pig temporal characteristics is also similar to that of humans - they are present at birth and mature rapidly post-natally. The time-course of CFF maturation is similar for rod and cone mediated responses. CONCLUSIONS: These data show that the temporal response and its maturation in the guinea pig retina is similar to that in humans. Therefore, we propose that the guinea pig is a particularly useful animal model to study retinal disease in early childhood.
Publisher: Public Library of Science (PLoS)
Date: 31-12-2013
Publisher: Springer Science and Business Media LLC
Date: 2002
Abstract: This paper considers the recommendation that Oscillatory Potentials (OP) be extracted by filtering in the frequency domain. This recommendation presumes that filtering isolates OPs from other ERG waveforms. However, we show that the leading edge of the a-wave has substantial frequency overlap with the OP spectrum at high intensities and that it contaminates these wavelets in the frequency domain. We propose a method of signal conditioning that removes a-waves prior to filtering. When this is done, the OPs show a bimodal distribution in the frequency domain that is well approximated by two Gaussians having means (+/-std. dev.) of 91.0 +/- 14.6 Hz and 153.1 +/- 17.1 Hz. This implies that two functions can be used to model the OPs in the time domain. However, we show that as most of the power of the Fourier spectrum (74%) is contained in a single Gaussian, a reasonable OP model can be derived by using a single function in the time domain. We test such a model on humans (n=5) and pigmented (n=14) and albino (n=14) guinea-pigs and show that it provides excellent fits to data across a range of flash exposures. Furthermore, changes in OP litude and timing between strains of guinea-pigs are easily detected with this model. We show that there is no statistical justification for making the model more complex by including multiple functions. Such paramatisation of the OP envelope provides a valuable and intuitive description of the OP waveforms in the time domain. The model provides an excellent description of OPs obtained with the current paradigm, however the single gaussian model may be deficient under stimulus conditions which produce highly asymmetric OP envelopes.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for James Armitage.