ORCID Profile
0000-0002-2457-1823
Current Organisations
Medical University of Vienna
,
University of Aberdeen
,
Chinese Academy of Sciences
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Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.IJROBP.2013.08.007
Abstract: Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE). CT images of 125 treated patients (32 head and neck [HN], 40 thorax, 23 liver, and 30 prostate) in 7 independent institutions were autosegmented using SPICE and computational times were recorded. The number of structures autocontoured were 25 for the HN, 7 for the thorax, 3 for the liver, and 6 for the male pelvis regions. Using the clinical contours as reference, autocontours of 22 selected structures were quantitatively evaluated using Dice Similarity Coefficient (DSC) and Mean Slice-wise Hausdorff Distance (MSHD). All 40 autocontours were evaluated by a radiation oncologist from the institution that treated the patients. The mean computational times to autosegment all the structures using SPICE were 3.1 to 11.1 minutes per patient. For the HN region, the mean DSC was >0.70 for all evaluated structures, and the MSHD ranged from 3.2 to 10.0 mm. For the thorax region, the mean DSC was 0.95 for the lungs and 0.90 for the heart, and the MSHD ranged from 2.8 to 12.8 mm. For the liver region, the mean DSC was >0.92 for all structures, and the MSHD ranged from 5.2 to 15.9 mm. For the male pelvis region, the mean DSC was >0.76 for all structures, and the MSHD ranged from 4.8 to 10.5 mm. Out of the 40 autocontoured structures reviews by experts, 25 were scored useful as autocontoured or with minor edits for at least 90% of the patients and 33 were scored useful autocontoured or with minor edits for at least 80% of the patients. Compared with manual contouring, autosegmentation using SPICE for the HN, thorax, liver, and male pelvis regions is efficient and shows significant promise for clinical utility.
Publisher: Wiley
Date: 26-01-2021
DOI: 10.1002/OSP4.477
Abstract: Many countries have implemented various levels of lockdown to mitigate the spread of the global SARS‐CoV‐2 pandemic. In the United Kingdom, the national lockdown restrictions were implemented between 26 March 2020 and 4 July 2020. These restrictions required all restaurants to close except for takeaway and delivery services. Moreover, in iduals were instructed to largely stay in their homes, unless they were identified as essential workers, and to only leave home once per day for exercise. These restrictions might have an impact on energy intake and expenditure, thereby affecting their body weight. The aim of this study was to investigate the impact of the movement restrictions in the United Kingdom on food outlet usage and body mass index (BMI). Food outlet usage surveys were filled out for 7 consecutive days before and during the lockdown. Changes in BMI and food outlet usage before and during the lockdown were measured. A total of 206 participants were included in this study. The mean overall BMI prior to lockdown was 25.8 ± 5.2 kg·m 2 , and during the lockdown, it was 25.9 ± 5.3 kg·m 2 ( t = 0.19, p = 0.85). Restaurant usage fell to zero as all establishments were closed. There was a corresponding increase in the use of delivery services to 1.18 ± 0.13 times per week, compared to 0.50 ± 0.05 prior to lockdown ( t = 4.44, p 0.0001). No significant difference in the number of takeaway meals ordered was observed (0.67 ± 0.06 before the lockdown and 0.74 ± 0.12 times per week during the lockdown t = 0.52, p = 0.60). There was no significant relationship between change in use of fast‐food restaurants and full‐service restaurants and the change in BMI, either alone or in combination ( β = −0.012, p = 0.62, R 2 = 0.11%). Despite the large changes in behavior, there was no overall adverse effect of the lockdown with respect to obesity levels. Lockdown in the United Kingdom modified restaurant use but had no effect on obesity levels.
Publisher: Elsevier BV
Date: 07-2022
DOI: 10.1093/AJCN/NQAC078
Publisher: Springer Science and Business Media LLC
Date: 28-06-2023
DOI: 10.1038/S41586-023-06249-4
Abstract: Caloric restriction that promotes weight loss is an effective strategy for treating non-alcoholic fatty liver disease and improving insulin sensitivity in people with type 2 diabetes 1 . Despite its effectiveness, in most in iduals, weight loss is usually not maintained partly due to physiological adaptations that suppress energy expenditure, a process known as adaptive thermogenesis, the mechanistic underpinnings of which are unclear 2,3 . Treatment of rodents fed a high-fat diet with recombinant growth differentiating factor 15 (GDF15) reduces obesity and improves glycaemic control through glial-cell-derived neurotrophic factor family receptor α-like (GFRAL)-dependent suppression of food intake 4–7 . Here we find that, in addition to suppressing appetite, GDF15 counteracts compensatory reductions in energy expenditure, eliciting greater weight loss and reductions in non-alcoholic fatty liver disease (NAFLD) compared to caloric restriction alone. This effect of GDF15 to maintain energy expenditure during calorie restriction requires a GFRAL–β-adrenergic-dependent signalling axis that increases fatty acid oxidation and calcium futile cycling in the skeletal muscle of mice. These data indicate that therapeutic targeting of the GDF15–GFRAL pathway may be useful for maintaining energy expenditure in skeletal muscle during caloric restriction.
Publisher: Springer Science and Business Media LLC
Date: 11-03-2019
DOI: 10.1038/S41598-019-40576-9
Abstract: Some large herbivores exhibit seasonal adjustments in their energy metabolism. Therefore, our aim was to determine if the llama (one of the most extensively kept livestock breeds) exhibits seasonal adjustment of their energy expenditure, body temperature and locomotion, under its natural high altitude Andean habitat. For this purpose, energy expenditure, body temperature and locomotion were measured in seven non-pregnant llama dams for ten months on the Andean High Plateau (4400 m above sea level). Daily energy expenditure was measured as field metabolic rate using the doubly labelled water method at four different measurement times. Additionally, a telemetry system was used to continuously record activity, body temperature (3 min intervals) as well as the position (hourly) of each animal. The results show that llamas adjusted their body temperature and daily energy expenditure according to environmental conditions. Furthermore, llamas under high altitude Andean climatic conditions exhibited a pronounced daily rhythm in body temperature and activity, with low values at sunrise and increasing values towards sunset. Llamas also had remarkably low energy expenditure compared to other herbivores. Thus, despite the domestication process, llamas have not lost the ability to adjust their body temperature and daily energy expenditure under adverse environmental conditions, similar to some wild herbivores.
Publisher: Springer Science and Business Media LLC
Date: 03-2002
DOI: 10.1007/S00066-002-0902-2
Abstract: Quality of life (QOL) measures give patients the possibility to express subjective changes in wellbeing. We aimed to translate the radiation specific quality of life questionnaire (QOL-RTI) and the companion head and neck module (H&N) questionnaire into German and to test its reliability, validity and sensitivity. After translation and final revisions based on qualitative interviews with ten patients, 97 head and neck cancer patients were screened for eligibility. Patients answered the 38 items questionnaire at baseline and twice in week 4 of radiotherapy for test-retest reliability. Internal consistency was calculated using Chronbach's alpha. Patients also completed the functional assessment of cancer tool plus head and neck (FACT-G plus H&N) for concurrent validity. Item analyses were performed to test the sensitivity. Chronbach's alpha yielded alpha = 0.85 for the QOL-RTI and alpha = 0.80 for the H&N module, test-retest reliability scores were r = 0.87 and r = 0.83, respectively. The correlation of the QOL-RTI plus H&N and the FACT plus H&N was r = 0.79. Questionnaire sensitivity was supported by significant changes in the mean score of 45.8% of the QOL-RTI items and 78.6% of the H&N items between baseline and week 4 of radiotherapy. The German version of the QOL-RTI was shown to be a reliable, valid and sensitive tool to assess the quality of life of patients undergoing radiotherapy. The H&N module is useful for patients undergoing treatment for head and neck cancer.
Publisher: Springer Science and Business Media LLC
Date: 02-2004
DOI: 10.1007/S00066-004-1160-2
Abstract: This study tested a three-item questionnaire to measure global quality of life (QOL) and pain in patients commencing radiotherapy, based on items from the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 instrument. In a pretest, the EORTC QLQ-C30 and the three-item short questionnaire were administered to 100 patients, yielding similar global QOL and pain scores. After the pretest, the three-item questionnaire was administered to 1,837 patients prior to first radiotherapy treatment. 254 (13.8%) patients with impaired QOL were identified. These patients had a mean global QOL score of 32.6 compared to 72.4 (p < 0.001) found in patients with satisfactory QOL. Patients with impaired QOL were also more likely < 60 years and treated for lung, gastrointestinal or head and neck cancer or advanced, metastatic cancer. This brief questionnaire addresses important aspects of QOL, is feasible to use in a clinical setting and therefore represents a potentially useful tool for detecting those patients who may benefit from further evaluation and/or psychosocial support.
Publisher: Springer Science and Business Media LLC
Date: 02-08-2023
Publisher: The Royal Society
Date: 09-2023
Publisher: Wiley
Date: 15-02-2022
DOI: 10.1002/OSP4.579
Abstract: The United Kingdom (UK) implemented several national lockdowns during the coronavirus pandemic during which restaurants were closed and people were advised to stay at home if possible. These restrictions were eased and reapplied multiple times between March 2020 and May 2021. The change in restaurant access and prolonged restriction of activity may have an impact on body weight. The aim of this study was to examine the impact of multiple lockdowns on body mass index (BMI) change from pre‐pandemic till during the third lockdown and on the use of different types of food outlets and their association with BMI change. Surveys of usage of different types of food outlets were distributed online before the lockdown between 06 January and 12 December 2019 and during the third national lockdown between 29 March and 25 April 2021. The food outlet usage surveys were filled out for seven consecutive days. Self‐reported BMI was reported before the pandemic and during the third phase of the lockdown. The total number of in iduals who started the study before the pandemic was 681, and 60 participants completed the surveys during the third phase of lockdown. For the 60 participants in both surveys mean BMI was significantly higher during the third lockdown (28.6 ± 5.9 kg.m 2 ) in comparison with the mean BMI before the pandemic 2019 (28.0 ± 5.5 kg.m 2 ) (paired T = 3.09, p 0.003). There was a significant positive association between BMI change, total number of days spent in lockdown ( β = 0.05, p 0.01, R 2 = 9.99), and age ( β = 0.06, p 0.007, R 2 = 11.8). There was no significant association between change in BMI and change in the frequency of using fast food restaurants (FFRs), full‐service restaurants (FSRs), and delivery and takeaways. BMI was increased significantly during the lockdown in comparison with prior to the pandemic. In iduals gained more weight the longer they stayed at home during lockdowns, and physical activity was reduced to approximately half. However, the BMI change was not related to the change in use of different types of food outlets. This pattern does not support the widespread belief that visiting restaurants or using delivery and takeaway services has a significant impact on body weight.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Speakman John.