ORCID Profile
0000-0003-0988-2583
Current Organisations
University of New South Wales
,
Australian National University
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Publisher: Springer Science and Business Media LLC
Date: 12-10-2011
DOI: 10.1038/NATURE10424
Publisher: Springer US
Date: 1995
Publisher: Oxford University Press (OUP)
Date: 26-07-2011
DOI: 10.1002/STEM.666
Abstract: Activin/Nodal signaling is necessary to maintain pluripotency of human embryonic stem cells (hESCs) and to induce their differentiation toward endoderm. However, the mechanisms by which Activin/Nodal signaling achieves these opposite functions remain unclear. To unravel these mechanisms, we examined the transcriptional network controlled in hESCs by Smad2 and Smad3, which represent the direct effectors of Activin/Nodal signaling. These analyses reveal that Smad2/3 participate in the control of the core transcriptional network characterizing pluripotency, which includes Oct-4, Nanog, FoxD3, Dppa4, Tert, Myc, and UTF1. In addition, similar experiments performed on endoderm cells confirm that a broad part of the transcriptional network directing differentiation is downstream of Smad2/3. Therefore, Activin/Nodal signaling appears to control ergent transcriptional networks in hESCs and in endoderm. Importantly, we observed an overlap between the transcriptional network downstream of Nanog and Smad2/3 in hESCs whereas, functional studies showed that both factors cooperate to control the expression of pluripotency genes. Therefore, the effect of Activin/Nodal signaling on pluripotency and differentiation could be dictated by tissue specific Smad2/3 partners such as Nanog, explaining the mechanisms by which signaling pathways can orchestrate ergent cell fate decisions.
Publisher: Frontiers Media SA
Date: 20-11-2017
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/AH19247
Abstract: ObjectiveThe aim of this study was to assess the clinical, economic and personal impacts of the nurse practitioner-led Sydney Adventist Hospital Community Palliative Care Service (SanCPCS) MethodsParallel economic analysis of usual care was conducted prospectively with patients from the enhanced SanCPCS. A convenient retrospective s le from the initial service was used to determine the impact of the enhanced service on patient care. A time series survey was used with patients and carers from within the expanded service group in order to measure patient outcomes and values as they approached death. ResultsPatients of the SanCPCS were less likely to die in hospital and had fewer hospital admissions. In addition, the service halved the estimated hospitalisation cost per patient, but the length of hospital stay was not affected by the service. The SanCPCS was more beneficial for women in terms of fewer hospital admissions and lower costs. Patients’ choices regarding place of care and death and what was ‘important’ to them changed over time. For instance, patients tended to prefer being at home as they approached death, and being pain free doubled in importance. ConclusionsNurse practitioner-led community palliative care services have the potential to result in significant economic and personal benefits for patients and their families in need of such care. What is known about the topic?National trends show an emphasis on community services with the aim of promoting and supporting the choice of dying at home, and this coincides with drives to reduce hospital costs and length of stay. Community-based palliative care services may offer substantial economic and clinical benefits. What does this paper add?The SanCPCS was the first nurse practitioner-led community-based palliative care service in Australia. The expansion of this service led to significantly fewer admissions and deaths in hospital, and halved the estimated hospitalisation cost per patient. What are implications for practitioners?Nurse practitioner-led models for care in the out-patient or community setting are a logical direction for palliative services through the engagement of specialised providers uniquely trained to support, nurture, guide and educate patients and their carers.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-02-2020
Abstract: Intravenous thrombolytic therapy ( IVT ) with tissue plasminogen activator for acute ischemic stroke is underutilized in many parts of the world. Randomized trials to test the effectiveness of thrombolysis implementation strategies are limited. This study aimed to test the effectiveness of a multicomponent, multidisciplinary tissue plasminogen activator implementation package in increasing the proportion of thrombolyzed cases while maintaining accepted benchmarks for low rates of intracranial hemorrhage and high rates of functional outcomes at 3 months. A cluster randomized controlled trial of 20 hospitals in the early stages of thrombolysis implementation across 3 Australian states was undertaken. Monitoring of IVT rates during the baseline period allowed hospitals (the unit of randomization) to be grouped into 3 baseline IVT strata—very low rates (0% to ≤4.0%) low rates ( .0% to ≤10.0%) and moderate rates ( .0%). Hospitals were randomized to an implementation package (experimental group) or usual care (control group) using a 1:1 ratio. The 16‐month intervention was based on behavioral theory and analysis of the steps, roles, and barriers to rapid assessment for thrombolysis eligibility and involved comprehensive strategies addressing in idual and system‐level change. The primary outcome was the difference in tissue plasminogen activator proportions between the 2 groups postintervention. The absolute difference in postintervention IVT rates between intervention and control hospitals adjusted for baseline IVT rate and stratum was not significant (primary outcome rate difference=1.1% (95% CI −1.5% to 3.7% P =0.38). Rates of intracranial hemorrhage remained below international benchmarks. The implementation package resulted in no significant change in tissue plasminogen activator implementation, suggesting that ongoing support is needed to sustain initial modifications in behavior. URL : www.anzctr.org.au Unique identifiers: ACTRN 12613000939796 and U1111‐1145‐6762
Publisher: Wiley
Date: 15-12-1995
DOI: 10.1113/JPHYSIOL.1995.SP021081
Abstract: 1. The neurophysiological basis for the increase in breathing associated with exercise remains obscure. The present study uses positron emission tomography (PET) to measure relative regional cerebral blood flow (rCBF) in order to identify sites of increased neuronal activation during and immediately following exercise. 2. Male volunteers underwent H2(15)O PET scanning during two complementary studies. Firstly, six subjects performed right leg exercise, adequate to increase oxygen uptake 2.5-fold. Secondly, five different subjects were scanned immediately following bicycle exercise (adequate to increase oxygen uptake 5-fold) while breathing was still increased. In each study, as a control, scanning was also performed during matched passive isocapnic positive pressure ventilation additionally, in the first study, passive right leg movement was performed. 3. Increases in relative rCBF were obtained in each in idual and co-registered with their magnetic resonance image of the brain defining in idual gyral morphology. 4. During exercise, in idual and group analysis revealed significant relative rCBF increases in the left and right superomedial primary motor cortex (the motor cortical 'leg' areas) and also in the left and right superolateral primary motor cortex in areas previously shown to be associated with volitional breathing. After exercise, there was no significant increase in relative rCBF in the superomedial areas but such increases were still present bilaterally in the superolateral areas which had been activated during the exercise. Other relative rCBF increases were also found, both during and after exercise, in cortical and subcortical areas known to be involved in motor control. 5. The results from PET scans during and after exercise, taken together, provide evidence for motor cortical involvement in the exercise-related hyperpnoea in man.
Publisher: Massachusetts Medical Society
Date: 05-02-2015
Publisher: Elsevier BV
Date: 06-1995
Publisher: Elsevier BV
Date: 03-2002
Publisher: Springer Science and Business Media LLC
Date: 25-03-2014
Publisher: Public Library of Science (PLoS)
Date: 30-06-2009
Publisher: Springer Science and Business Media LLC
Date: 11-2002
Publisher: Wiley
Date: 12-1981
DOI: 10.1113/JPHYSIOL.1981.SP013985
Abstract: 1. The mechanical resistance of the human forearm to imposed sinusoidal movements has been determined. By means of a visual monitor, subjects maintained a steady force (typically 100 N) by flexing the elbow so as to pull with the wrist against an isometric force transducer. This was mounted upon a stretcher which displaced the forearm sinusoidally at frequencies of 7-11 Hz with a peak-to-peak litude of movement of about 1 mm. The average mechanical resistance over 10-40 sec of stretching was analysed into its vector components at the fundamental of the stretching frequency. Observations were made of both the normal resistance and that obtained while applying continuous vibration at 100 Hz to the tendon of either the biceps (agonist) or triceps (antagonist).2. In confirmation of Joyce, Rack & Ross (1974), at frequencies around 10 Hz the normal (unvibrated) response sometimes showed a component of negative viscosity' (force increasing during muscle shortening), rather than the simple ositive viscosity' attributable to muscle visco-elasticity this effect is attributable to the stretch reflex being appropriately delayed and of sufficient magnitude to over-ride the inherent properties of muscle. Vibration of either agonist or antagonist usually increased the extent of the negative viscosity' (negative quadrature component of force), as well as changing the elastic' stiffness of the arm (in-phase component of force).3. More commonly, the component of viscosity was initially positive. It was then normally reduced by vibration that is, the vibration had (in formal terms) again added a component of negative viscosity.4. The vibration did not produce these effects by acting directly upon the contractile system of muscle to reduce its visco-elasticity'. On increasing the frequency of stretching the effect of vibration systematically shifted from being the addition of a negative viscosity, as above, to being the addition of a positive viscosity. These effects may all be attributed to an action of vibration on the stretch reflex, with the precise action of the reflex determined by the relation between the cycle time and the delays round the reflex pathway.5. In some experiments the activity of the flexor muscles was s led by surface electromyograms from biceps and from brachioradialis these were rectified, smoothed and averaged. For biceps, the absolute depth of e.m.g. modulation in relation to the cycle of stretching was sometimes, but not always, increased by vibration but for brachioradialis the modulation was always reduced. Thus vibration cannot invariably produce its effects on the mechanical resistance of the arm by increasing the size (gain) of the stretch reflex. However, in all subjects the phase of the electromyographic modulation of both muscles was significantly delayed during vibration, whether of biceps or of triceps. In comparison with the normal, vibration introduced a phase lag on average of 18 degrees . In qualitative terms, this can be shown to explain the typical augmentation of negative viscosity'.6. The findings are discussed in relation to the genesis of tremor and to the reflex regulation of muscle contraction. They support the classical idea that afferent activity from the antagonist is as crucially implicated as that from the agonist.
Publisher: Nanyang Technol. Univ
Date: 2002
Publisher: American Chemical Society (ACS)
Date: 10-08-2015
Publisher: Springer Science and Business Media LLC
Date: 10-1994
DOI: 10.1007/BF00181069
Publisher: Elsevier BV
Date: 06-1997
DOI: 10.1016/S0165-0270(96)02253-4
Abstract: In the past 15 years positron emission tomography (PET) has become a settled method of imaging the functioning human brain, both in normal volunteers and in patients with various disorders. Much of the work on sensory systems has been on the visual system, a conveniently studied and very important part of the brain. The motor system in health and disease has attracted as much interest. In this short review I will explain some of the technical aspects of PET, and illustrate some of the research that has been done on visual and motor brain function in the human.
Publisher: Elsevier BV
Date: 09-1984
DOI: 10.1016/0166-4328(84)90169-4
Abstract: Normal adult subjects attempted, with vision excluded, to match the position of the left index finger by pointing to it with the right one, using only flexion-extension movements at the right elbow. An elastic load applied at the right wrist was altered from trial to trial. When instructed to align the fingers, subjects were found to select the position of the right forearm by taking into account both a position signal and some measure of the force exerted by the elbow flexors. When instructed to match a target force, instead of position, the subjects were able to give greater weighting to signals of force than in the position matching task.
Publisher: Wiley
Date: 10-1995
DOI: 10.1113/JPHYSIOL.1995.SP020947
Abstract: 1. The role of supra-brainstem structures in the ventilatory response to inhaled CO2 is unknown. The present study uses positron emission tomography (PET), with infusion of H2(15)O, to measure changes in relative regional cerebral blood flow (rCBF) in order to identify sites of increased neuronal activation during CO2-stimulated breathing (CO2-SB) in awake man. 2. Five male volunteers were scanned during CO2-SB (mean +/- S.E.M. end-tidal PCO2, 50.3 +/- 1.7 mmHg respiratory frequency, 16.4 +/- 2.7 min-1 tidal volume, 1.8 +/- 0.2 l). As control, scans were performed during 'passive' isocapnic (elevated fraction of inspired CO2) positive pressure ventilation (end-tidal PCO2, 38.4 +/- 1.0 mmHg respiratory frequency, 15.5 +/- 2.2 min-1 tidal volume, 1.6 +/- 0.2 l). With CO2-SB, all subjects reported dyspnoea. 3. The anatomical locations of the increases in relative rCBF (CO2-SB versus control) were obtained using magnetic resonance imaging. 4. Group analysis identified neuronal activation within the upper brainstem, midbrain and hypothalamus, thalamus, hippoc us and parahippoc us, fusiform gyrus, cingulate area, insula, frontal cortex, temporo-occipital cortex and parietal cortex. No neuronal activation was seen within the primary motor cortex (at sites previously shown to be associated with volitional breathing). 5. These results suggest neuronal activation within the limbic system this activation may be important in the sensory and/or motor respiratory responses to hypercapnia in awake man.
Publisher: BMJ
Date: 10-1994
Abstract: The localised PET cerebral correlates of the painful experience in the normal human brain have previously been demonstrated. This study examined whether these responses are different in patients with chronic atypical facial pain. The regional cerebral responses to non-painful and painful thermal stimuli in six female patients with atypical facial pain and six matched female controls were studied by taking serial measurements of regional blood flow by PET. Both groups displayed highly significant differences in responses to painful heat compared with non-painful heat in the thalamus, anterior cingulate cortex (area 24), lentiform nucleus, insula, and prefrontal cortex. These structures are closely related to the "medial pain system". The atypical facial pain group had increased blood flow in the anterior cingulate cortex and decreased blood flow in the prefrontal cortex. These findings show the importance of the anterior cingulate cortex and the reciprocal (possibly inhibitory) connections with the prefrontal cortex in the processing of pain in patients with this disorder. A hypothesis is proposed to explain the mechanisms of cognitive and pharmacological manipulation of these pain processes.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 23-12-2009
DOI: 10.1002/HEP.23506
Abstract: Generation of hepatocytes from human embryonic stem cells (hESCs) could represent an advantageous source of cells for cell therapy approaches as an alternative to orthotopic liver transplantation. However, the generation of differentiated hepatocytes from hESCs remains a major challenge, especially using a method compatible with clinical applications. We report a novel approach to differentiate hESCs into functional hepatic cells using fully defined culture conditions, which recapitulate essential stages of liver development. hESCs were first differentiated into a homogenous population of endoderm cells using a combination of activin, fibroblast growth factor 2, and bone morphogenetic protein 4 together with phosphoinositide 3-kinase inhibition. The endoderm cells were then induced to differentiate further into hepatic progenitors using fibroblast growth factor 10, retinoic acid, and an inhibitor of activin/nodal receptor. After further maturation, these cells expressed markers of mature hepatocytes, including asialoglycoprotein receptor, tyrosine aminotransferase, alpha1-antitrypsin, Cyp7A1, and hepatic transcription factors such as hepatocyte nuclear factors 4alpha and 6. Furthermore, the cells generated under these conditions exhibited hepatic functions in vitro, including glycogen storage, cytochrome activity, and low-density lipoprotein uptake. After transduction with a green fluorescent protein-expressing lentivector and transplantation into immunodeficient uPA transgenic mice, differentiated cells engrafted into the liver, grew, and expressed human albumin and alpha1-antitrypsin as well as green fluorescent protein for at least 8 weeks. In addition, we showed that hepatic cells could be generated from human-induced pluripotent cells derived from reprogrammed fibroblasts, demonstrating the efficacy of this approach with pluripotent stem cells of erse origins. We have developed a robust and efficient method to differentiate pluripotent stem cells into hepatic cells, which exhibit characteristics of human hepatocytes. Our approach should facilitate the development of clinical grade hepatocytes for transplantation and for research on drug discovery.
Publisher: Public Library of Science (PLoS)
Date: 04-02-2013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 1998
DOI: 10.1097/00004728-199801000-00028
Abstract: Our goal was to validate linear and nonlinear intersubject image registration using an automated method (AIR 3.0) based on voxel intensity. PET and MRI data from 22 normal subjects were registered to corresponding averaged PET or MRI brain atlases using several specific linear and nonlinear spatial transformation models with an automated algorithm. Validation was based on anatomically defined landmarks. Automated registration produced results that were superior to a manual nine parameter variant of the Talairach registration method. Increasing the degrees of freedom in the spatial transformation model improved the accuracy of automated intersubject registration. Linear or nonlinear automated intersubject registration based on voxel intensities is computationally practical and produces more accurate alignment of homologous landmarks than manual nine parameter Talairach registration. Nonlinear models provide better registration than linear models but are slower.
Publisher: AMPCo
Date: 10-2001
DOI: 10.5694/J.1326-5377.2001.TB143658.X
Abstract: The clinical approach to the patient with a suspected disorder of memory and intellect is to establish whether it is dementia, which parts of the brain are affected, what is the cause, what is the prognosis, and what can be done about it. The diagnosis of dementia usually requires the involvement of memory and at least one other cognitive system. Delirium and depression are important differential diagnoses. Patients with dementia should usually have some simple investigations after a careful history-taking and examination to identify "reversible" causes. The commonest cause of dementia is Alzheimer's disease, in which short-term memory disturbance is usually prominent. Other causes of dementia include cerebrovascular disease, Lewy-body disease and Pick's disease. There is now hope for patients with Alzheimer's disease (which can be treated with some success with cholinesterase inhibitors) and patients with vascular dementia, in whom aggressive control of causal risk factors may retard progression.
Publisher: Elsevier BV
Date: 06-1995
Abstract: We have used PET (positron emission tomography) to chart the mapping of the retina in human occipital visual cortex and hence to locate the secondary and tertiary visual areas, V2 and V3. A group of four non-selected male volunteers was presented with dynamic stimuli that were aligned with either the vertical or the right horizontal meridians (VM or HM) from 0 degree to 29 degrees eccentricity the vertical stimuli were restricted to either the inferior or the superior hemifields. PET scans were performed using intravenous infusion of H215O and a Siemens-CTI 953B PET scanner with 3D data acquisition. Subjects received 18 scans, ided equally among the right HM, the superior VM, and the inferior VM. Data were analyzed with SPM software. The group average result confirmed our experimental hypothesis that human occipital visual cortex has retinotopic maps similar to those of the macaque monkey. Thus human areas V2 and V3 can be defined on the basis that the border between them is formed by the HM and that the outer border of V3 is demarcated by a second representation of the VM that runs approximately parallel to the primary representation of the VM at the V1/V2 border. Furthermore, as in many mammals, the extrastriate representation of the HM is "split", such that the superior contralateral quadrant is mapped in lower V2 and V3, occupying the ventral surface of human cortex, and the inferior contralateral quadrant is mapped in upper V2 and V3, which extend over the lateral and medial surfaces of each hemisphere. After stereotaxic normalization, the position of V3 defined by retinal topography was found to correspond to that surmised from our previous PET studies employing moving stimuli.
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.JOCN.2010.03.005
Abstract: A 44-year-old woman presented with focal retrograde amnesia and complaints of rapid forgetting in the absence of episodes of transient cognitive disturbance. Her MRI and 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET) were normal. On standard neuropsychological tests she performed within the normal range although a test of autobiographical memory confirmed impoverished recall especially involving recent life events. The electroencephalograph (EEG) recordings were suggestive of temporal lobe epilepsy but no clear diagnosis was established. After 4 years the patient's recurrent brief episodes of disorientation, suggestive of transient epileptic amnesia (TEA), were corroborated by her sister. This diagnosis was confirmed by an ambulatory EEG that revealed ictal activity. Several important points emerge from this study. Focal retrograde amnesia can be a prodromal symptom of TEA which can precede the full-blown syndrome by several years. Moreover, transient attacks might not be reported if patients live alone. The ictal EEG findings further substantiate the epileptic nature of the syndrome.
Publisher: Proceedings of the National Academy of Sciences
Date: 24-02-2003
Abstract: Understanding the relationship between the structural and functional organization of the human brain is one of the most important goals of neuroscience. In idual variability in brain structure means that it is essential to obtain this information from the same subject. To date, this has been almost impossible. Even though noninvasive functional imaging techniques such as functional MRI (fMRI) are now commonplace, there is no complementary noninvasive structural technique. We present an in vivo method of examining the detailed neuroanatomy of any in idual, which can then be correlated with that in idual's own functional results. This method utilizes high-resolution structural MRI to identify distinct cortical regions based on cortical lamination structure. We demonstrate that the observed MR lamination patterns relate to myeloarchitecture through a correlation of histology with MRI. In vivo high-resolution MRI studies identify striate cortex, as well as visual area V5, in four in iduals, as defined by using fMRI. The anatomical identification of a cortical area (V5/MT) outside of striate cortex is a significant advance, proving it possible to identify extra-striate cortical areas and demonstrating that in vivo structural mapping of the human cerebral cortex is possible.
Publisher: Elsevier BV
Date: 2001
DOI: 10.1016/S0028-3932(01)00041-0
Abstract: Pervasive retrograde amnesia without anterograde memory impairment has rarely been described as a consequence of circumscribed brain damage. We report this phenomenon in a 33 yr-old, right-handed man (JG) in association with the extension in the right thalamus of a previously small, bilateral thalamic lesion. JG presented with a dense amnesia for autobiographical material more than a few years old, with some sparing of recent memories. Furthermore, he was completely unable to recognise famous people or world events. Many other aspects of semantic knowledge were intact and there was no evidence of general intellectual impairment, executive dysfunction or loss of visual imagery. Magnetic resonance imaging revealed an acute lesion in the right thalamus and two small, symmetrical, bilateral non-acute thalamic lesions. Follow-up neuropsychological assessment indicated a stable pattern of impaired retrograde and spared anterograde memory over 18 months and psychiatric assessments yielded no evidence of confabulation, malingering or other symptoms to suggest psychogenic amnesia. JG's profile indicates that the ision of declarative memory into just two categories - episodic and semantic - is inadequate. Rather, his case adds to the growing body evidence to suggest that world knowledge pertaining to people and events is stored or accessed similarly to autobiographical information and differently from other types of more general factual knowledge. We hypothesize that the right mediodorsal thalamic nucleus and immediately surrounding regions comprise the central processing mechanism referred to by McClelland (Revue Neurologique, 150 (1994) 570) and Markowitsch (Brain Research Review, 21 (1995) 117) as responsible for inducing and co-ordinating the recall of these sorts of cortically stored memory engrams.
Publisher: Springer Science and Business Media LLC
Date: 09-2001
Abstract: Patients with Type II (non-insulin-dependent) diabetes mellitus are at increased risk of macrovascular and microvascular disease, both of which are reduced by controlling raised blood pressure in hypertensive patients. Intensive glycaemic control has also been shown to reduce microvascular disease but the effects on macrovascular disease remain uncertain. This study will examine the hypotheses that lowering blood pressure with an ACE inhibitor-diuretic combination and intensively controlling gylcaemia with a sulphonylurea-based regimen in high-risk patients with Type II diabetes (both hypertensive and non-hypertensive) reduces the incidence of macrovascular and microvascular disease. The study is a 2 x 2 factorial randomised controlled trial that will include 10000 adults with Type II diabetes at high risk of vascular disease. Following 6 weeks on open label perindopril-indapamide combination, eligible patients are randomised to continued perindopril-indapamide or matching placebo, and to an intensive gliclazide MR-based glucose control regimen or usual guidelines-based therapy. Primary outcomes are, first, the composite of nonfatal stroke, non-fatal myocardial infarction or cardiovascular death and, second, the composite of new or worsening nephropathy or diabetic eye disease. The scheduled average duration of treatment and follow-up is 4.5 years. The study will be conducted in approximately 200 centres in Australasia, Asia, Europe and North America. ADVANCE is designed to provide reliable evidence on the balance of benefits and risks conferred by blood pressure lowering therapy and intensive glucose control therapy in high-risk diabetic patients, regardless of initial blood pressure or glucose concentrations.
Publisher: Society for Neuroscience
Date: 03-1991
DOI: 10.1523/JNEUROSCI.11-03-00641.1991
Abstract: We have used positron emission tomography (PET), which measures regional cerebral blood flow (rCBF), to demonstrate directly the specialization of function in the normal human visual cortex. A novel technique, statistical parametric mapping, was used to detect foci of significant change in cerebral blood flow within the prestriate cortex, in order to localize those parts involved in the perception of color and visual motion. For color, we stimulated the subjects with a multicolored abstract display containing no recognizable objects (Land color Mondrian) and contrasted the resulting blood flow maps with those obtained when subjects viewed an identical display consisting of equiluminous shades of gray. The comparison identified a unique area (area V4) located in the lingual and fusiform gyri of the prestriate cortex. For motion, blood flow maps when subjects viewed moving or stationary black and white random-square patterns were contrasted. The comparison identified a unique area located in the region of the temporo-parieto-occipital junction (area V5). We thus provide direct evidence to show that, just as in the macaque monkey, different areas of the human prestriate visual cortex are specialized for different attributes of vision. The striate cortex (V1) and the contiguous visual area (V2), which in the monkey brain feed both the homologous areas, were active in all 4 conditions. This pattern of activity allowed us to use an extension of the approach to assess the functional relationship between the 3 areas during color and motion stimulation. This is based on an hypothesis-led analysis of the covariance structure of the blood flow maps and promises to be a powerful tool for inferring anatomical pathways in the normal human brain.(ABSTRACT TRUNCATED AT 250 WORDS)
Publisher: SAGE Publications
Date: 1996
DOI: 10.1097/00004647-199601000-00002
Abstract: The analysis of functional mapping experiments in positron emission tomography involves the formation of images displaying the values of a suitable statistic, summarising the evidence in the data for a particular effect at each voxel. These statistic images must then be scrutinised to locate regions showing statistically significant effects. The methods most commonly used are parametric, assuming a particular form of probability distribution for the voxel values in the statistic image. Scientific hypotheses, formulated in terms of parameters describing these distributions, are then tested on the basis of the assumptions. Images of statistics are usually considered as lattice representations of continuous random fields. These are more amenable to statistical analysis. There are various shortcomings associated with these methods of analysis. The many assumptions and approximations involved may not be true. The low numbers of subjects and scans, in typical experiments, lead to noisy statistic images with low degrees of freedom, which are not well approximated by continuous random fields. Thus, the methods are only approximately valid at best and are most suspect in single-subject studies. In contrast to the existing methods, we present a nonparametric approach to significance testing for statistic images from activation studies. Formal assumptions are replaced by a computationally expensive approach. In a simple rest-activation study, if there is really no activation effect, the labelling of the scans as “active” or “rest” is artificial, and a statistic image formed with some other labelling is as likely as the observed one. Thus, considering all possible relabellings, a p value can be computed for any suitable statistic describing the statistic image. Consideration of the maximal statistic leads to a simple nonparametric single-threshold test. This randomisation test relies only on minimal assumptions about the design of the experiment, is (almost) exact, with Type I error (almost) exactly that specified, and hence is always valid. The absence of distributional assumptions permits the consideration of a wide range of test statistics, for instance, “pseudo” t statistic images formed with smoothed variance images. The approach presented extends easily to other paradigms, permitting nonparametric analysis of most functional mapping experiments. When the assumptions of the parametric methods are true, these new nonparametric methods, at worst, provide for their validation. When the assumptions of the parametric methods are dubious, the nonparametric methods provide the only analysis that can be guaranteed valid and exact.
Publisher: Oxford University Press (OUP)
Date: 1995
Publisher: Elsevier BV
Date: 2002
DOI: 10.1046/J.1444-2892.2002.00127.X
Abstract: Medical outcomes following coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) are similar, but few studies have compared neuropsychological outcomes after these procedures. A retrospective study compared detailed neurocognitive and psychosocial functioning in 32 patients (CABG, n = 16 PTCA, n = 16) aged 61 +/- 6 years, 9-15 months after coronary revascularisation. Subjects were tested for executive functioning, speed of processing/attention and learning/memory, significant psychopathology (General Health Questionnaire, GHQ) and psychosocial functioning (Short Form (SF)-36 health survey). In the prospective study, 55 patients completed GHQ and SF-36 surveys, the day prior to and 6 months following PTCA. There were no significant differences between the CABG and PTCA groups for neuropsychological or psychosocial end-points (P > 0.20). Executive functioning in both groups, however, was worse than for healthy population controls (P 4 P < 0.01). After PTCA, however, there was a significant improvement in the GHQ and SF-36 scores (P < 0.05). Although executive function is often impaired after coronary revascularisation, neuropsychological status appears equivalent after CABG or PTCA. Psychiatric pathology is common in patients undergoing PTCA, but improves after this intervention.
Publisher: Springer Science and Business Media LLC
Date: 31-01-2013
Publisher: Elsevier BV
Date: 09-2001
Publisher: Oxford University Press (OUP)
Date: 1993
Abstract: In pursuing our work on the organization of human visual cortex, we wanted to specify more accurately the position of the visual motion area (area V5) in relation to the sulcal and gyral pattern of the cerebral cortex. We also wanted to determine the intersubject variation of area V5 in terms of position and extent of blood flow change in it, in response to the same task. We therefore used positron emission tomography (PET) to determine the foci of relative cerebral blood flow increases produced when subjects viewed a moving checkerboard pattern, compared to viewing the same pattern when it was stationary. We coregistered the PET images from each subject with images of the same brain obtained by magnetic resonance imaging, thus relating the position of V5 in all 24 hemispheres examined to the in idual gyral configuration of the same brains. This approach also enabled us to examine the extent to which results obtained by pooling the PET data from a small group of in iduals (e.g., six), chosen at random, would be representative of a much larger s le in determining the mean location of V5 after transformation into Talairach coordinates. After stereotaxic transformation of each in idual brain, we found that the position of area V5 can vary by as much as 27 mm in the left hemisphere and 18 mm in the right for the pixel with the highest significance for blood flow change. There is also an intersubject variability in blood flow change within it in response to the same visual task. V5 nevertheless bears a consistent relationship, within each brain, to the sulcal pattern of the occipital lobe. It is situated ventrolaterally, just posterior to the meeting point of the ascending limb of the inferior temporal sulcus and the lateral occipital sulcus. In position it corresponds almost precisely with Flechsig's Feld 16, one of the areas that he found to be myelinated at birth.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2019
DOI: 10.1161/STROKEAHA.118.023009
Abstract: This study reports the detailed effects of canagliflozin on stroke, stroke subtypes, and vascular outcomes in participants with and without cerebrovascular disease (stroke or transient ischemic attack) at baseline from the CANVAS (Canagliflozin Cardiovascular Assessment Study) Program. The CANVAS Program, comprising 2 similarly designed and conducted clinical trials, randomly assigned 10 142 participants with type 2 diabetes mellitus and high cardiovascular risk to canagliflozin or placebo. Its primary outcome was a composite of major adverse cardiovascular events. The main outcome of interest for this report was fatal or nonfatal stroke. Additional exploratory outcomes were stroke subtypes and other vascular outcomes defined according to standard criteria. There were 1 958 (19%) participants with prior stroke or transient ischemic attack at baseline. These in iduals were older, more frequently women, and had higher rates of heart failure, atrial fibrillation, and microvascular disease (all P .001) compared with those without such a history. There were 309 participants with stroke events during follow-up (123 had prior stroke or transient ischemic attack at baseline and 186 did not), at a rate of 7.93/1000 patient-years among those assigned canagliflozin and 9.62/1000 patient-years among placebo (hazard ratio, 0.87 95% CI, 0.69–1.09). Analysis of stroke subtypes found no effect on ischemic stroke (n=253, hazard ratio, 0.95 95% CI, 0.74–1.22), a significant reduction for hemorrhagic stroke (n=30, hazard ratio, 0.43 95% CI, 0.20–0.89) and no effect on undetermined stroke (n=29, hazard ratio, 1.04 95% CI, 0.48–2.22). Effects on other cardiovascular outcomes were comparable among participants with and without stroke or transient ischemic attack at baseline. There were too few events in the CANVAS Program to separately define the effects of canagliflozin on stroke, but benefit is more likely than harm. The observed possible protective effect for hemorrhagic stroke was based on small numbers but warrants further investigation. URL: www.clinicaltrials.gov . Unique identifiers: NCT01032629 and NCT01989754.
Publisher: Wiley
Date: 10-2000
DOI: 10.1046/J.1442-9071.2000.00345.X
Abstract: Susac syndrome is characterized by the triad of branch retinal arterial occlusions, encephalopathy and cochlear microangiopathy. The underlying process is believed to be a small vessel vasculitis causing microinfarcts in the retina, brain and cochlea. Analysis of two male and two female cases of Susac syndrome recognized in Australia. In this series the epidemiology, mode of presentation, ophthalmologic features, neurologic and cochleo-vestibular features, radiologic characteristics, cerebrospinal fluid findings, therapeutic interventions, clinical course and outcome of Susac syndrome is examined. Key ophthalmologic differential diagnoses include systemic lupus erythematosis (SLE), Behçet's syndrome and other vasculitides such as sarcoidosis, tuberculosis, syphilis and lymphoma. Neuro-otologic features are most frequently misdiagnosed as multiple sclerosis. Susac syndrome, first described in 1979, is becoming an increasingly recognized condition. Early recognition of the syndrome is important because treatment with systemic immunosuppression may minimize permanent cognitive, audiologic and visual sequelae.
Publisher: Springer Science and Business Media LLC
Date: 21-07-2020
Publisher: Elsevier BV
Date: 11-2000
Publisher: Wiley
Date: 12-11-2004
DOI: 10.1002/HBM.20082
Publisher: The Royal Society
Date: 22-06-1993
Abstract: There are many instances in which human subjects perceive a component which is not physically present in a visual stimulus. To study the cerebral activity which correlates with the perception of such an illusory component, we chose Enigma, a static figure in which many subjects perceive illusory motion. By using the technique of positron emission tomography (PET) we recorded the relative regional cerebral blood flow (rCBF) in the brain of 13 subjects while they viewed it and reported seeing the illusory motion. We found that, when subjects perceived illusory motion, the increases in rCBF took place in regions of the brain closely related to, and perhaps identical with, area V5, as defined by the site of rCBF change that took place when the same subjects viewed a physically moving stimulus. In addition, there was activity in other cortical areas outside the visual cortex, not present when the subjects had been viewing objective motion. This suggests that the generation of illusory motion depends not only on a highly specific visual area but also on relative contributions from other parts of the brain that are not activated to the same extent when humans perceive objective motion.
Publisher: Springer Science and Business Media LLC
Date: 16-07-2022
DOI: 10.1007/S00405-022-07523-3
Abstract: Superficial siderosis, a progressive, debilitating, neurological disease, often presents with bilateral impairment of auditory and vestibular function. We highlight that superficial siderosis is often due to a repairable spinal dural defect of the type that can also cause spontaneous intracranial hypotension. Retrospective chart review of five patients presenting with moderate to severe, progressive bilateral sensorineural hearing loss as well as vestibular loss. All patients had developed superficial siderosis from spinal dural defects: three after trauma, one after spinal surgery and one from a thoracic discogenic microspur. The diagnosis was made late in all five patients despite surgical repair in four, hearing and vestibular loss failed to improve. In patients presenting with progressive bilateral sensorineural hearing loss, superficial siderosis should be considered as a possible cause. If these patients also have bilateral vestibular loss, cerebellar impairment and anosmia, then the diagnosis is likely and the inevitable disease progress might be halted by finding and repairing the spinal dural defect.
Publisher: BMJ
Date: 03-1991
Abstract: Two cases of aseptic meningitis occurred in temporal association with high dose intravenous immunoglobulin therapy to treat thrombocytopenia. In neither case was any other aetiological agent identified and both patients completely recovered within a few days. This phenomenon has been reported in only one previous paediatric case.
Publisher: Springer Science and Business Media LLC
Date: 06-1992
DOI: 10.1007/BF00867593
Publisher: Massachusetts Medical Society
Date: 05-11-1998
Publisher: Oxford University Press (OUP)
Date: 12-1993
Abstract: We used the technique of PET to determine whether visual signals reach visual area V5, specialized for visual motion, when a human patient, blinded by a lesion in area V1, discriminates the direction of motion of visual stimuli and shows, through his verbal reports, that he is consciously aware of both the nature of the visual stimulus and its direction of motion. The results showed that area V5 was active without a parallel activation of area V1, implying that the visual input can reach V5 without passing first through V1 and that such an input is sufficient for both the discrimination and the conscious awareness of the visual stimulus.
Publisher: Informa UK Limited
Date: 12-2003
DOI: 10.1076/NEUR.9.6.504.29375
Abstract: Recent case studies of amnesic patients have yielded patterns of impairment that challenge Tulving's (1972) ision of retrograde memory into two categories (namely, episodic and semantic memory). Here we describe a patient (JG) who developed partially blocked access to previously stored knowledge following the onset of a medial thalamic infarction. Having previously demonstrated that JG has a dense, pervasive amnesia for autobiographical material, famous people and famous events (Miller et al. , 2001), in this study, we show that he is unable to access information about unique entities across a range of domains. In contrast, his memory for more general semantic knowledge (such as word meanings) is intact. JG's memory impairment is discussed in the context of a model of neural functioning put forward by Damasio (1990), in which it was proposed that recall of unique entities depends on many cortical regions being activated in synchrony. This activity, thought to be triggered and coordinated by anterior temporal and frontal lobe regions is, in turn, modulated by projections from the thalamus. We propose that JG's thalamic lesion has disrupted the coordination of the diffuse cortical networks necessary to generate highly specific memories from the past, be they episodic or semantic.
Publisher: Elsevier BV
Date: 02-1999
Abstract: A moving plaid is a composite pattern produced by superimposing two sinusoidal gratings which differ in orientation and motion direction. The perceived drift direction of a plaid appears to be determined partly by a binocular mechanism, which follows intersection of constraint rules (Burke and Wenderoth, 1993b), and partly by a monocular mechanism, which tracks the dark and bright intersects of the plaid, the contrast envelopes. The first neurones that respond to plaids as patterns rather than component gratings are found in area V5, also known as MT, which is exclusively binocular. Therefore, the psychophysical evidence suggesting that the contrast envelope tracking mechanism is monocular is surprising but has been obtained consistently. We aimed to localize the contrast envelope tracking mechanism by undertaking a positron emission tomography (PET) activation experiment in which the subjects were presented with alternating plaid components during the control scan and with the moving plaid resulting from the superposition of these components as the activation scan. The results showed differential activation in area V3. Recent results from macaque single cell recordings have also demonstrated increased sensitivity to moving plaid stimuli compared to the plaid component gratings in V3 neurones.
Publisher: Wiley
Date: 08-12-2015
DOI: 10.1111/DOM.12589
Abstract: To assess the efficacy and safety of canagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes enrolled in the CANagliflozin cardioVascular Assessment Study (CANVAS) who were on an incretin mimetic [dipeptidyl peptidase-4 (DPP-4) inhibitor or glucagon-like peptide-1 (GLP-1) receptor agonist]. CANVAS is a double-blind, placebo-controlled study that randomized participants to canagliflozin 100 or 300 mg or placebo added to routine therapy. The present post hoc analysis assessed the efficacy and safety of canagliflozin 100 and 300 mg compared with placebo in subsets of patients from CANVAS who were taking background DPP-4 inhibitors or GLP-1 receptor agonists with or without other antihyperglycaemic agents at week 18. Of the 4330 patients in CANVAS, 316 were taking DPP-4 inhibitors and 95 were taking GLP-1 receptor agonists. At 18 weeks, canagliflozin 100 and 300 mg provided larger placebo-subtracted reductions in glycated haemoglobin (HbA1c) in patients taking DPP-4 inhibitors [-0.56% (95% confidence interval [CI]: -0.77, -0.35), and -0.75% (95% CI: -0.95, -0.54), respectively] and GLP-1 receptor agonists [-1.00% (95% CI: -1.35, -0.65), and -1.06% (95% CI: -1.43, -0.69), respectively]. Body weight and blood pressure (BP) reductions were seen with canagliflozin versus placebo in both subsets. Higher incidences of genital mycotic infections and osmotic diuresis-related adverse events (AEs) were seen with canagliflozin compared with placebo. The incidence of hypoglycaemia was numerically higher with canagliflozin versus placebo nearly all events occurred in patients on background insulin or insulin secretagogues. In patients on background incretin mimetics, canagliflozin improved HbA1c, body weight and BP, with an increased incidence of AEs related to SGLT2 inhibition.
Publisher: American Society for Clinical Investigation
Date: 09-2010
DOI: 10.1172/JCI43122
Publisher: BMJ
Date: 24-03-2016
Publisher: Wiley
Date: 23-06-2005
DOI: 10.1111/J.1464-5491.2005.01596.X
Abstract: The primary aim of ADVANCE is to determine the effects on macrovascular and microvascular disease of blood pressure lowering (with an ACE inhibitor-diuretic combination), irrespective of initial blood pressure level and of intensive glucose lowering, in high-risk in iduals with Type 2 diabetes. The study is a 2 x 2 factorial randomized controlled trial. Following 6 weeks on active perindopril-indapamide combination, eligible participants were randomized to perindopril/indapamide (initially 2.0/0.625 mg daily, increasing to 4.0/1.25 mg daily after 3 months) or matching placebo and to an intensive gliclazide MR-based glucose control regimen aiming for a haemoglobin A1c (HbA1c) value of 6.5% or lower, or local standard therapy. The study is being conducted in 215 centres in 20 countries within Australasia, Asia, Europe and North America. Recruitment commenced in June 2001 and was completed in March 2003, with the inclusion of 11,140 randomized participants. Fifty-seven per cent of participants are male and the mean age at baseline was 66 years. On average, the diagnosis of diabetes was made 8 years before study entry. At baseline 32 and 10% of patients had a history of macrovascular and microvascular disease, respectively. The mean blood pressure at baseline was 145/81 mmHg the mean HbA1c concentration was 7.5%. While blood pressure and HbA1c values were broadly similar, certain characteristics of randomized participants varied between countries. With successful worldwide recruitment completed, ADVANCE should provide reliable and broadly generalizable results on the effects of routine blood pressure lowering and intensive glucose control in high-risk in iduals with Type 2 diabetes.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2016.09.005
Abstract: Interoception is the ability to consciously perceive internal bodily states. Neuroimaging suggests that the insula (IC) and anterior cingulate cortex (ACC) mediate interoception, while studies involving patients/animals with brain lesions suggest the medial temporal lobe (MTL) is particularly important. One reason for these contrasting conclusions may lie in the types of interoceptive task used by these different approaches. Some tasks probably require integration of current physiological state with mnemonic information (e.g., how much one last ate), and these may be especially reliant upon MTL processing. We compared one task that probably requires integration - a water load task - with one that likely does not - a heart-rate tracking task - in two in iduals with selective MTL damage (and with intact IC and ACC). A group of matched healthy in iduals served as controls. The main finding was that in iduals with MTL damage, relative to controls, were equally and significantly impaired on both types of interoception task. This suggests that MTL structures are involved in mediating interoception even when using a task (heart rate tracking) that does not seemingly require memory and that in neuroimaging studies activates the IC and ACC. The reasons for this apparent inconsistency with neuroimaging findings and the functional role of the MTL in interoception are discussed.
Publisher: Oxford University Press (OUP)
Date: 1994
Abstract: Brain activity during reading tasks was investigated using PET. The aim was to account for differences in the results of two previous studies [those of Petersen et al. (Science 1990 249: 1041-4) and Howard et al. (Brain 1992 115: 1769-82)] by systematically varying the type of reading task and the exposure duration of the word stimuli. Both variables strongly influenced patterns of brain activity. There were three types of task: (i) reading aloud (ii) reading silently and (iii) lexical decision on visually presented words and pseudowords. Reading aloud and reading silently engaged the left middle and superior temporal regions, confirming the important role of these areas in visual word processing. The areas principally engaged during lexical decision were the left inferior and middle frontal cortices and the supplementary motor area activity in these areas suggests that the subjects were using a phonological strategy to perform the task. There was also a significant effect of exposure duration, with activity being greater for short (150 ms) exposure durations than for long (1000 ms or 981 ms) exposure durations. We conclude that until we understand how subtle variations in experimental design influence brain activity during reading tasks, the association of specific processing functions with in idual anatomical areas activated during reading is premature.
Publisher: AMPCo
Date: 09-1998
Publisher: Springer Science and Business Media LLC
Date: 26-09-2012
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1016/S1053-8119(03)00116-2
Abstract: This study investigated the possible benefit of subject specific optimization of preprocessing strategies in functional magnetic resonance imaging (fMRI) experiments. The optimization was performed using the data-driven performance metrics developed recently [Neuroimage 15 (2002), 747]. We applied numerous preprocessing strategies and a multivariate statistical analysis to each of the 20 subjects in our two ex le fMRI data sets. We found that the optimal preprocessing strategy varied, in general, from subject to subject. For ex le, in one data set, optimum smoothing levels varied from 16 mm (4 subjects), 10 mm (5 subjects), to no smoothing at all (1 subject). This strongly suggests that group-specific preprocessing schemes may not give optimum results. For both studies, optimizing the preprocessing for each subject resulted in an increased number of suprathresholded voxels in within-subject analyses. Furthermore, we demonstrated that we were able to aggregate the optimized data with a random effects group analysis, resulting in improved sensitivity in one study and the detection of interesting, previously undetected results in the other.
Publisher: Public Library of Science (PLoS)
Date: 22-09-2021
DOI: 10.1371/JOURNAL.PONE.0257713
Abstract: Synaesthesia refers to a erse group of perceptions. These unusual perceptions are defined by the experience of concurrents these are conscious experiences that are catalysed by attention to some normally unrelated stimulus, the inducer . In grapheme-colour synaesthesia numbers, letters, and words can all cause colour concurrents , and these are independent of the actual colour with which the graphemes are displayed. For ex le, when seeing the numeral ‘3’ a person with synaesthesia might experience green as the concurrent irrespective of whether the numeral is printed in blue, black, or red. As a trait, synaesthesia has the potential to cause both positive and negative effects. However, regardless of the end effect, synaesthesia incurs an initial cost when compared with its equivalent ex le from normal perception this is the additional processing cost needed to generate the information on the concurrent . We contend that this cost can be reduced by mirroring the concurrent in the environment. We designed the Digital-Colour Calculator (DCC) app, allowing each user to personalise and select the colours with which it displays its digits it is the first reported ex le of a device/approach that leverages the concurrent. In this article we report on the reactions to the DCC for a s le of fifty-three synaesthetes and thirty-five non-synaesthetes. The synaesthetes showed a strong preference for the DCC over its normal counterpart. The non-synaesthetes showed no obvious preference. When using the DCC a subs le of the synaesthete group showed consistent improvement in task speed (around 8%) whereas no synaesthete showed a decrement in their speed.
Publisher: Informa UK Limited
Date: 27-11-2019
DOI: 10.1080/13554794.2019.1695846
Abstract: Here we present the case of SP, a 21-year-old female with life-long dyscalculia. SP was subsequently diagnosed with grapheme-color synesthesia, a diagnosis that serendipitously catalyzed our development of a novel aid:The digit-color calculator (DCC). The DCC substantiates SP's color
Publisher: CSIRO
Date: 2015
Publisher: Elsevier
Date: 1993
Publisher: BMJ
Date: 28-08-2014
Publisher: Oxford University Press (OUP)
Date: 2000
Abstract: Regional cerebral blood flow (rCBF) was measured with PET in seven healthy subjects while they carried out a mental rotation task in which they decided whether alphanumeric characters presented in different orientations were in their canonical form or mirror-reversed. Consistent with previous findings, subjects took proportionally longer to respond as characters were rotated further from the upright, indicating that they were mentally rotating the characters to the upright position before making a decision. We used a parametric design in which we varied the mental rotation demands in an incremental fashion while keeping all other aspects of the task constant. In four different scanning conditions, 10, 40, 70 or 100% of the stimuli presented during the scan required mental rotation while the rest were upright. The statistical parametric mapping technique was used to identify areas where changes in rCBF were correlated with the rotational demands of the task. Significant activation was found in only one area located in the right posterior parietal lobe, centred on the intraparietal sulcus (Brodmann area 7). The experimental literature on monkeys and humans suggests that this area is involved in a variety of spatial transformations. Our results contribute evidence that such transformations are recruited during mental rotation and add to a body of evidence which suggests that the right posterior parietal lobe is important for carrying out visuospatial transformations.
Publisher: MIT Press - Journals
Date: 2005
Abstract: Functional magnetic resonance imaging was performed in 16 healthy subjects while they undertook orientation discrimination tasks of real rotating and mentally rotating alphanumeric characters. Perception of rotating and stationary abstract characters was also performed. Mental rotation and the perception of alphanumeric characters undergoing real rotation activated equivalent cortical areas, in keeping with the analogue hypothesis of mental rotation. In addition, areas along the dorsal stream, including the V5/middle temporal complex and the intraparietal sulcus (IPS), were activated during both the real and imaginary rotary conditions. Within the parietal lobe there were areas of convergence (i.e., recruited by all three motion conditions) and areas of ergence (i.e., selectively activated by a particular condition). Tasks requiring canonical-mirror orientation discrimination revealed involvement of neural substrates localized to the ventrolateral bank of the IPS. Tasks in which this judgment was not performed and during which the subject viewed rotary motion of abstract stimuli recruited activity in the medial bank of the IPS. These results indicate subspecialization of the human posterior parietal lobe according to function.
Publisher: Massachusetts Medical Society
Date: 03-08-2000
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2002
DOI: 10.1097/00004872-200212000-00032
Abstract: To determine the relative importance of recognised risk factors for non-haemorrhagic stroke, including serum cholesterol and the effect of cholesterol-lowering therapy, on the occurrence of non-haemorrhagic stroke in patients enrolled in the LIPID (Long-term Intervention with Pravastatin in Ischaemic Disease) study. The LIPID study was a placebo-controlled, double-blind trial of the efficacy on coronary heart disease mortality of pravastatin therapy over 6 years in 9014 patients with previous acute coronary syndromes and baseline total cholesterol of 4-7 mmol/l. Following identification of patients who had suffered non-haemorrhagic stroke, a pre-specified secondary end point, multivariate Cox regression was used to determine risk in the total population. Time-to-event analysis was used to determine the effect of pravastatin therapy on the rate of non-haemorrhagic stroke. There were 388 non-haemorrhagic strokes in 350 patients. Factors conferring risk of future non-haemorrhagic stroke were age, atrial fibrillation, prior stroke, diabetes, hypertension, systolic blood pressure, cigarette smoking, body mass index, male sex and creatinine clearance. Baseline lipids did not predict non-haemorrhagic stroke. Treatment with pravastatin reduced non-haemorrhagic stroke by 23% (P = 0.016) when considered alone, and 21% (P = 0.024) after adjustment for other risk factors. The study confirmed the variety of risk factors for non-haemorrhagic stroke. From the risk predictors, a simple prognostic index was created for non-haemorrhagic stroke to identify a group of patients at high risk. Treatment with pravastatin resulted in significant additional benefit after allowance for risk factors.
Publisher: AMPCo
Date: 03-1993
DOI: 10.5694/J.1326-5377.1993.TB121837.X
Abstract: To review the clinical features, treatment and outcome of patients with central nervous system (CNS) tuberculosis. A retrospective analysis of the case records of patients diagnosed as having CNS tuberculosis in a large Australian teaching hospital. Twenty-two patients with CNS tuberculosis were identified between 1978 and 1989. Six patients (age range, 17-78 years) were Australian-born whites, seven patients (age range, 21-68 years) were overseas settlers in Australia and nine patients (age range, 14-56 years) were New Caledonians. The diagnoses included tuberculous meningitis, intracranial tuberculomas and intracranial tuberculous abscesses. These were confirmed by microbiology and/or histopathology in 16 patients and were presumptive in the remaining six. All patients were treated with antituberculous drugs and 14 received corticosteroids as well. Fourteen patients made a full recovery and two had mild residual neurological disability. Four patients died and two were left with severe residual disability. The neurological state of seven patients (all non-whites) deteriorated paradoxically after they started taking the antituberculous drugs. The diagnosis of CNS tuberculosis may be difficult to make, so therapy based on a presumptive diagnosis will often be needed because of the poor outcome if treatment is delayed. Computed tomographic scanning helps the initial diagnosis and demonstrates the processes underlying paradoxical deterioration, which may occur in the face of adequate antituberculous treatment. Corticosteroids are effective in treating this uncommon complication.
Publisher: Cambridge University Press (CUP)
Date: 2000
DOI: 10.1017/S1355617700611116
Abstract: Fifty-eight studies of the neuropathological and neuropsychological outcomes of cerebral anoxia were reviewed. Neuropathological reports were examined for the variety, extent, and specificity of lesions resulting from an anoxic event. While most attention has focused on damage to the hippoc us following anoxic brain injury, the review indicated that watershed cerebral cortex and the basal ganglia were both more frequently damaged than the hippoc us. The hippoc us was the sole affected structure in only 18% of reported cases. Neurological, neuropsychological and psychiatric studies were analyzed. Of 67 in idual case reports, a memory disturbance was documented in 36 (54%), but a memory disturbance without report of additional cognitive deficits occurred in only 13 (19.4%). Changes in personality and behavior were noted in 31 (46.2%). Visuospatial or, less frequently, visual recognition problems were noted in 21 in idual cases (31.3%) reviewed. Memory deficits were found in all 14 group studies reviewed, while in 9 papers changes in behavior or personality were also documented. Six studies also reported visuospatial deficits. Careful reading of the literature reveals a range of cognitive and behavioral changes that reflect very well the neuropathological outcomes of anoxic episodes. ( JINS , 2000, 6 , 86–99.)
Publisher: Elsevier BV
Date: 1997
Abstract: We have used the technique of positron emission tomography to study and compare the cortical activity produced when humans view a pattern of small squares moving incoherently with respect to one another and when the same pattern moves coherently and unidirectionally. A stationary version of the stimulus acted as a control. Our choice of paradigm was inspired by psychophysical models and physiological studies in the macaque monkey which show that directionally selective cells in V5 respond optimally to unidirectional coherent motion, whereas those of V1 respond to motion within their receptive fields, regardless of the motion in surrounding parts. Our results show that human V1/V2, V3, and V5 are all activated by both types of motion stimuli. Incoherent motion, however, proved to be more effective than coherent motion in activating V1/V2 and V5. Thus the higher perceptual salience of unidirectional coherent motion in comparison to incoherent motion is not reflected by any increased activation of human area V5.
Publisher: Springer Science and Business Media LLC
Date: 2004
Publisher: SAGE Publications
Date: 06-1998
DOI: 10.1097/00004647-199806000-00012
Abstract: Angiogenesis is one of the therapeutic targets of cerebral infarction. Long noncoding RNAs (lncRNAs) can regulate the pathological process of angiogenesis following ischemic stroke. Taurine-upregulated gene 1 (TUG1), an lncRNA, is correlated to ischemic stroke. We intended to determine the effect of TUG1 on angiogenesis following an ischemic stroke. Middle cerebral artery occlusion (MCAO) was adopted to build a focal ischemic model of the rat brain, and pcDNA-TUG1 and miR-26a mimics were injected into rats. Neurological function was estimated through modified neurological severity scores. The volume of focal brain infarction was calculated through 2,3,5-triphenyltetrazolium chloride staining. The level of TUG1 and miR-26a was measured by PCR. The expression of vascular endothelial growth factor (VEGF) and CD31 was checked using immunohistochemistry and western blot. The correlation between miR-26a and TUG1 was verified through a luciferase reporter assay. TUG1 increased noticeably while miR-26a was markedly reduced in MCAO rats. Overexpression of miR-26a improved neurological function recovery and enhanced cerebral angiogenesis in MCAO rats. TUG1 overexpression aggravated neurological deficits and suppressed cerebral angiogenesis in MCAO rats. Bioinformatics analysis revealed that miR-26a was one of the predicted targets of TUG1. Furthermore, TUG1 combined with miR-26a to regulate angiogenesis. TUG1 overexpression antagonized the role of miR-26a in neurological recovery and angiogenesis in MCAO rats. TUG1/miR-26a, which may act as a regulatory axis in angiogenesis following ischemic stroke, can be considered a potential target for cerebral infarction therapy.
Publisher: Wiley
Date: 11-1996
DOI: 10.1111/J.1440-1681.1996.TB01144.X
Abstract: 1. The past decade has seen a burgeoning of functional imaging studies of cerebral activity in normal humans. Much of this work has been performed on the visual system, which is an important and often conveniently studied part of the brain. 2. Previously, what we believed about the functional anatomy of the human visual system was almost entirely obtained by studying in idual patients with cerebral lesions and from experiments in animals. Early functional imaging experiments were often quite simple, descriptive exercises. 3. Techniques such as positron emission tomography have become quite mature with this and increasing experience on the part of the investigators, the experiments performed have become more novel. Functional imaging methods have become part of the mainstream of investigations to be used for research on vision. They already have led to novel hypotheses about how aspects of this system work.
Publisher: Mark Allen Group
Date: 02-05-2019
DOI: 10.12968/IJPN.2019.25.5.245
Abstract: Patients want community-based palliative care, but there was no continuity of care for patients at the Sydney Adventist Hospital to receive palliative and end-of-life care within a community setting. A nurse practitioner (NP)-led community palliative care service was developed. To present the background, design, function, and essential elements of the Sydney Adventist Hospital Community Palliative Care Service (SanCPCS). Semi-structured and cyclical discussions with key informants alongside internal document reviews. This is the first description of an NP-led community palliative care service model. The NP role ensured specialist training and extended clinical practice within the community setting. The SanCPCS delivers accessible, continuous, community-based palliative care throughout the patient's palliative and end-of-life journey. NP-led models for palliative and end-of-life care in the outpatient or community setting are a logical direction to meet patient need.
Publisher: Oxford University Press (OUP)
Date: 1995
Abstract: In a small proportion of the normal population, stimulation in one modality can lead to perceptual experience in another, a phenomenon known as synaesthesia. In the most common form of synaesthesia, hearing a word can result in the experience of colour. We have used the technique of PET, which detects brain activity as changes of regional cerebral blood flow (rCBF), to study the physiology of colour-word synaesthesia in a group of six synaesthete women. During rCBF measurements synaesthetes and six controls were blindfolded and were presented with spoken words or pure tones. Auditory word, but not tone, stimulation triggered synaesthesia in synaesthetes. In both groups word stimulation compared with tone stimulation activated the classical language areas of the perisylvian regions. In synaesthetes, a number of additional visual associative areas, including the posterior inferior temporal cortex and the parieto-occipital junctions, were activated. The former has been implicated in the integration of colour with shape and in verbal tasks which require attention to visual features of objects to which words refer. Synaesthetes also showed activations in the right prefrontal cortex, insula and superior temporal gyrus. By contrast, no significant activity was detected in relatively lower visual areas, including areas V1, V2 and V4. These results suggest that colour-word synaesthesia may result from the activity of brain areas concerned with language and visual feature integration. In the case of colour-word synaesthesia, conscious visual experience appears to occur without activation of the primary visual cortex.
Publisher: Wiley
Date: 08-1981
DOI: 10.1113/JPHYSIOL.1981.SP013830
Abstract: 1. A study has been made of the effect of continuous vibration, at 150 Hz, upon the response of muscle spindle afferents to low frequency sinusoidal stretching (1 and 8 Hz). Using the soleus muscle of the anaesthetized cat, with severed ventral roots, recordings were made of single Ia afferents and of the massed Ia afferent discharges in the main bulk of the cut L7 dorsal root. 2. When the litude of vibration was large (50 micrometers, short pulses) and that of the sinusoidal stretching was not too great (50-100 micrometers, peak-to-peak) the discharge of the afferents was largely locked 1:1 to the vibration and the response to the sinusoidal stretching was abolished. 3. When the litude of the vibration was reduced to below that eliciting continuous afferent driving, then the response to sinusoidal stretching of any litude was often markedly increased. This arose through the vibration having a much more powerful excitatory action during the rising phase of the sinusoidal stretch than it did during the falling phase. 4. Averaged over a full cycle, the phase of the response to the sinusoidal stretching tended to be delayed during the vibration in comparison with the normal. This was largely dependent upon the afferents continuing to respond maximally to the vibration around the peak of the sinusoidal stretch, at which stage their unvibrated response is declining, rather than to a phase lag of the whole pattern of response. 5. The results are discussed in relation to the effects of vibration on tremor and the human stretch reflex, and on the determination of the frequency-response of spindle afferents.
Publisher: Wiley
Date: 13-06-2006
DOI: 10.1002/HBM.20267
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for John D. G. Watson.