Responses of intraspecific metabolic scaling to temperature and activity differ between water- and air-breathing ectothermic vertebrates.

Metabolism underpins all life-sustaining processes and varies profoundly with body size, temperature and locomotor activity. A current theory explains some of the size-dependence of metabolic rate (its mass exponent, b) through changes in metabolic level (L). We propose two predictive advances that: (a) combine the above theory with the evolved avoidance of oxygen limitation in water-breathers experiencing warming, and (b) quantify the overall magnitude of combined temperatures and degrees of locomotion on metabolic scaling across air- and water-breathers. We use intraspecific metabolic scaling responses to temperature (523 regressions) and activity (281 regressions) in diverse ectothermic vertebrates (fish, reptiles and amphibians) to show that b decreases with temperature-increased L in water-breathers, supporting surface area-related avoidance of oxygen limitation, whereas b increases with activity-increased L in air-breathers, following volume-related influences. This new theoretical integration quantitatively incorporates different influences (warming, locomotion) and respiration modes (aquatic, terrestrial) on animal energetics.

ssVERDICT: Self-supervised VERDICT-MRI for enhanced prostate tumor characterization.

PURPOSE: Demonstrating and assessing self-supervised machine-learning fitting of the VERDICT (vascular, extracellular and restricted diffusion for cytometry in tumors) model for prostate cancer. METHODS: We derive a self-supervised neural network for fitting VERDICT (ssVERDICT) that estimates parameter maps without training data. We compare the performance of ssVERDICT to two established baseline methods for fitting diffusion MRI models: conventional nonlinear least squares and supervised deep learning. We do this quantitatively on simulated data by comparing the Pearson's correlation coefficient, mean-squared error, bias, and variance with respect to the simulated ground truth. We also calculate in vivo parameter maps on a cohort of 20 prostate cancer patients and compare the methods' performance in discriminating benign from cancerous tissue via Wilcoxon's signed-rank test. RESULTS: In simulations, ssVERDICT outperforms the baseline methods (nonlinear least squares and supervised deep learning) in estimating all the parameters from the VERDICT prostate model in terms of Pearson's correlation coefficient, bias, and mean-squared error. In vivo, ssVERDICT shows stronger lesion conspicuity across all parameter maps, and improves discrimination between benign and cancerous tissue over the baseline methods. CONCLUSION: ssVERDICT significantly outperforms state-of-the-art methods for VERDICT model fitting and shows, for the first time, fitting of a detailed multicompartment biophysical diffusion MRI model with machine learning without the requirement of explicit training labels.

Medications and cognitive risk in Aboriginal primary care: a cross-sectional study.

BACKGROUND: Aboriginal and Torres Strait Islander people are ageing with high rates of comorbidity, yet little is known about suboptimal prescribing in this population. AIM: The prevalence of potentially suboptimal prescribing and associated risk factors were investigated among older patients attending primary care through Aboriginal Community Controlled Health Services (ACCHSs). METHODS: Medical records of 420 systematically selected patients aged ≥50 years attending urban, rural and remote health services were audited. Polypharmacy (≥ 5 prescribed medications), potentially inappropriate medications (PIMs) as per Beers Criteria and anticholinergic burden (ACB) were estimated and associated risk factors were explored with logistic regression. RESULTS: The prevalence of polypharmacy, PIMs and ACB score ≥3 was 43%, 18% and 12% respectively. In multivariable logistic regression analyses, polypharmacy was less likely in rural (odds ratio (OR) = 0.43, 95% confidence interval (CI) = 0.24-0.77) compared to urban patients, and more likely in those with heart disease (OR = 2.62, 95% CI = 1.62-4.25), atrial fibrillation (OR = 4.25, 95% CI = 1.08-16.81), hypertension (OR = 2.14, 95% CI = 1.34-3.44), diabetes (OR = 2.72, 95% CI = 1.69-4.39) or depression (OR = 1.91, 95% CI = 1.19-3.06). PIMs were more frequent in females (OR = 1.88, 95% CI = 1.03-3.42) and less frequent in rural (OR = 0.41, 95% CI = 0.19-0.85) and remote (OR = 0.58, 95% CI = 0.29-1.18) patients. Factors associated with PIMs were kidney disease (OR = 2.60, 95% CI = 1.37-4.92), urinary incontinence (OR = 3.00, 95% CI = 1.02-8.83), depression (OR = 2.67, 95% CI = 1.50-4.77), heavy alcohol use (OR = 2.83, 95% CI = 1.39-5.75) and subjective cognitive concerns (OR = 2.69, 95% CI = 1.31-5.52). High ACB was less common in rural (OR = 0.10, 95% CI = 0.03-0.34) and remote (OR = 0.51, 95% CI = 0.25-1.04) patients and more common in those with kidney disease (OR = 3.07, 95% CI = 1.50-6.30) or depression (OR = 3.32, 95% CI = 1.70-6.47). CONCLUSION: Associations between potentially suboptimal prescribing and depression or cognitive concerns highlight the importance of considering medication review and deprescribing for these patients.

Oral glucose tolerance test-The imperfect gold standard for gestational diabetes screening: A qualitative study involving clinicians in regional, rural and remote areas of Western Australia.

ISSUE ADDRESSED: The oral glucose tolerance test is the 'gold standard' for detecting gestational diabetes in Australian and International guidelines. Test completion in regional, rural and remote regions may be as low as 50%. We explored challenges and enablers for regional, rural and remote antenatal clinicians providing gestational diabetes screening to better understand low oral glucose tolerance test completion. METHODS: We conducted a qualitative descriptive study using semi-structured interviews. Participants eligible for the study were doctors or midwives providing antenatal care in regional, rural and remote Western Australia, between August 2019 and November 2020. Interviews were recorded digitally and transcribed into a Word document. We conducted a thematic analysis after initial categorisation and deduction of themes through workshops involving the research team. RESULTS: We found a diversity of viewpoints on oral glucose tolerance test reliability for detecting gestational diabetes. Themes that emerged were; good collaboration between antenatal clinicians is required for successful screening; screening occurs throughout pregnancy using various tests; clinicians make significant efforts to address barriers; clinicians prioritise therapeutic relationships. CONCLUSIONS: Effective universal screening for gestational diabetes in regional, rural and remote Western Australia is difficult and more complex in practice than guidelines imply. Detecting gestational diabetes requires creative solutions, early identification of at risk women and trust and collaboration between clinicians and women. SO WHAT?: Detection of gestational diabetes in regional, rural and remote Western Australia remains poorly completed. New strategies are required to adequately identify women at risk of adverse birth outcomes relating to hyperglycaemia in pregnancy.

Aboriginal young people's experiences of type 2 diabetes diagnosis, management and support: A qualitative study in the Kimberley region of Western Australia.

ISSUES ADDRESSED: In Australia, Aboriginal and Torres Strait Islander young people in remote settings are most-affected by young onset type 2 diabetes (T2D). It is necessary to understand young people's experiences, including factors impacting on self-management, to improve models of care. METHODS: A phenomenological methodology underpinned this qualitative study in Western Australia's Kimberley region. Two Aboriginal Community Controlled Health Services supported recruitment of seven Aboriginal young people aged 12-24 with T2D, who participated in interviews. A carer and health professional of one young person in each site were also interviewed and relevant medical record data reviewed to assist with triangulation of data. De-identified transcripts were inductively coded and a coding structure developed with oversight by a Kimberley Aboriginal researcher. RESULTS: Young people reported varied experiences and emotions relating to a T2D diagnosis. Most recounted this was upsetting and some reported current negative impact on emotional wellbeing. Challenges with understanding and managing diabetes were highlighted, particularly regarding healthy eating, physical activity and medication. Family are a prominent source of self-management support, with the intergenerational impact of diabetes being evident for each participant. Positive relationships with health professionals, entailing continuity of care, were valued. CONCLUSIONS: There are significant emotional and medical challenges for young people with T2D and their families. Recommendations from this work will contribute to the development of local resources and initiatives to improve diabetes-related support. SO WHAT?: Alongside broader efforts to support good health at the societal level, enhanced health education and family-oriented support structures including Aboriginal clinical staff for young people with T2D are needed.

Prevalence of functional limitations in older remote-living Aboriginal Australians.

INTRODUCTION: To better tailor prevention and care strategies, there is a need to identify modifiable factors associated with functional impairment in older Aboriginal people, and related service needs. OBJECTIVE: To investigate the prevalence and associated factors for functional impairment in older Aboriginal people, and related service needs. DESIGN: Cross-sectional survey of 289 Aboriginal people aged ≥45 years living in the remote Kimberley region of Western Australia. Factors associated with functional impairment were explored with logistic regression. FINDINGS: 41.2% (95% CI 35.6%-47.0%) of participants required assistance with at least one I/ADL, and 26.0% (95% CI 21.2%-31.3%) required assistance with two or more I/ADLs. A core activity limitation (required assistance with showering, dressing or cooking) was reported by 15.9% (95% CI 12.1%-20.6%). In multivariable logistic regression analyses, older age, diabetes, difficulty walking, head injury, higher depression score and worse cognition were associated with needing help with two or more I/ADLs, while older age, history of stroke, higher depression score and worse cognition were associated with the presence of a core activity limitation. The proportion of participants receiving support with I/ADLs ranged from 71.2% to 97.6%. Support was generally provided by family and friends rather than service providers. DISCUSSION: The key modifiable factors associated with functional impairment in older Aboriginal people living in remote regions are diabetes, depression and cognitive impairment. Services required are transport and socio-cultural activities, and ensuring support for family providing the majority of care. CONCLUSIONS: This study highlights the need for holistic prevention strategies and care for older Aboriginal people with functional limitations and their families.

Human apoA-I[Lys107del] mutation affects lipid surface behavior of apoA-I and its ability to form large nascent HDL.

Population studies have found that a natural human apoA-I variant, apoA-I[K107del], is strongly associated with low HDL-C but normal plasma apoA-I levels. We aimed to reveal properties of this variant that contribute to its unusual phenotype associated with atherosclerosis. Our oil-drop tensiometry studies revealed that compared to WT, recombinant apoA-I[K107del] adsorbed to surfaces of POPC-coated triolein drops at faster rates, remodeled the surfaces to a greater extent, and was ejected from the surfaces at higher surface pressures on compression of the lipid drops. These properties may drive increased binding of apoA-I[K107del] to and its better retention on large triglyceride-rich lipoproteins, thereby increasing the variant's content on these lipoproteins. While K107del did not affect apoA-I capacity to promote ABCA1-mediated cholesterol efflux from J774 cells, it impaired the biogenesis of large nascent HDL particles resulting in the formation of predominantly smaller nascent HDL. Size-exclusion chromatography of spontaneously reconstituted 1,2-dimyristoylphosphatidylcholine-apoA-I complexes showed that apoA-I[K107del] had a hampered ability to form larger complexes but formed efficiently smaller-sized complexes. CD analysis revealed a reduced ability of apoA-I[K107del] to increase α-helical structure on binding to 1,2-dimyristoylphosphatidylcholine or in the presence of trifluoroethanol. This property may hinder the formation of large apoA-I[K107del]-containing discoidal and spherical HDL but not smaller HDL. Both factors, the increased content of apoA-I[K107del] on triglyceride-rich lipoproteins and the impaired ability of the variant to stabilize large HDL particles resulting in reduced lipid:protein ratios in HDL, may contribute to normal plasma apoA-I levels along with low HDL-C and increased risk for CVD.

Quantification of Prostate Cancer Metabolism Using 3D Multiecho bSSFP and Hyperpolarized [1-13 C] Pyruvate: Metabolism Differs Between Tumors of the Same Gleason Grade.

BACKGROUND: Three-dimensional (3D) multiecho balanced steady-state free precession (ME-bSSFP) has previously been demonstrated in preclinical hyperpolarized (HP) 13 C-MRI in vivo experiments, and it may be suitable for clinical metabolic imaging of prostate cancer (PCa). PURPOSE: To validate a signal simulation framework for the use of sequence parameter optimization. To demonstrate the feasibility of ME-bSSFP for HP 13 C-MRI in patients. To evaluate the metabolism in PCa measured by ME-bSSFP. STUDY TYPE: Retrospective single-center cohort study. PHANTOMS/POPULATION: Phantoms containing aqueous solutions of [1-13 C] lactate (2.3 M) and [13 C] urea (8 M). Eight patients (mean age 67 ± 6 years) with biopsy-confirmed Gleason 3 + 4 (n = 7) and 4 + 3 (n = 1) PCa. FIELD STRENGTH/SEQUENCES: 1 H MRI at 3 T with T2 -weighted turbo spin-echo sequence used for spatial localization and spoiled dual gradient-echo sequence used for B0 -field measurement. ME-bSSFP sequence for 13 C MR spectroscopic imaging with retrospective multipoint IDEAL metabolite separation. ASSESSMENT: The primary endpoint was the analysis of pyruvate-to-lactate conversion in PCa and healthy prostate regions of interest (ROIs) using model-free area under the curve (AUC) ratios and a one-directional kinetic model (kP ). The secondary objectives were to investigate the correlation between simulated and experimental ME-bSSFP metabolite signals for HP 13 C-MRI parameter optimization. STATISTICAL TESTS: Pearson correlation coefficients with 95% confidence intervals and paired t-tests. The level of statistical significance was set at P < 0.05. RESULTS: Strong correlations between simulated and empirical ME-bSSFP signals were found (r > 0.96). Therefore, the simulation framework was used for sequence optimization. Whole prostate metabolic HP 13 C-MRI, observing the conversion of pyruvate into lactate, with a temporal resolution of 6 seconds was demonstrated using ME-bSSFP. Both assessed metrics resulted in significant differences between PCa (mean ± SD) (AUC = 0.33 ± 012, kP  = 0.038 ± 0.014) and healthy (AUC = 0.15 ± 0.10, kP  = 0.011 ± 0.007) ROIs. DATA CONCLUSION: Metabolic HP 13 C-MRI in the prostate using ME-bSSFP allows for differentiation between aggressive PCa and healthy tissue. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Avoiding Unnecessary Biopsy after Multiparametric Prostate MRI with VERDICT Analysis: The INNOVATE Study.

Background In men suspected of having prostate cancer (PCa), up to 50% of men with positive multiparametric MRI (mpMRI) findings (Prostate Imaging Reporting and Data System [PI-RADS] or Likert score of 3 or higher) have no clinically significant (Gleason score ≤3+3, benign) biopsy findings. Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumor (VERDICT) MRI analysis could improve the stratification of positive mpMRI findings. Purpose To evaluate VERDICT MRI, mpMRI-derived apparent diffusion coefficient (ADC), and prostate-specific antigen density (PSAD) as determinants of clinically significant PCa (csPCa). Materials and Methods Between April 2016 and December 2019, men suspected of having PCa were prospectively recruited from two centers and underwent VERDICT MRI and mpMRI at one center before undergoing targeted biopsy. Biopsied lesion ADC, lesion-derived fractional intracellular volume (FIC), and PSAD were compared between men with csPCa and those without csPCa, using nonparametric tests subdivided by Likert scores. Area under the receiver operating characteristic curve (AUC) was calculated to test diagnostic performance. Results Among 303 biopsy-naive men, 165 study participants (mean age, 65 years ± 7 [SD]) underwent targeted biopsy; of these, 73 had csPCa. Median lesion FIC was higher in men with csPCa (FIC, 0.53) than in those without csPCa (FIC, 0.18) for Likert 3 (P = .002) and Likert 4 (0.60 vs 0.28, P < .001) lesions. Median lesion ADC was lower for Likert 4 lesions with csPCa (0.86 × 10-3 mm2/sec) compared with lesions without csPCa (1.12 × 10-3 mm2/sec, P = .03), but there was no evidence of a difference for Likert 3 lesions (0.97 × 10-3 mm2/sec vs 1.20 × 10-3 mm2/sec, P = .09). PSAD also showed no difference for Likert 3 (0.17 ng/mL2 vs 0.12 ng/mL2, P = .07) or Likert 4 (0.14 ng/mL2 vs 0.12 ng/mL2, P = .47) lesions. The diagnostic performance of FIC (AUC, 0.96; 95% CI: 0.93, 1.00) was higher (P = .02) than that of ADC (AUC, 0.85; 95% CI: 0.79, 0.91) and PSAD (AUC, 0.74; 95% CI: 0.66, 0.82) for the presence of csPCa in biopsied lesions. Conclusion Lesion fractional intracellular volume enabled better classification of clinically significant prostate cancer than did apparent diffusion coefficient and prostate-specific antigen density. Clinical trial registration no. NCT02689271 © RSNA, 2022 Online supplemental material is available for this article.

Termites have wider thermal limits to cope with environmental conditions in savannas.

The most diverse and abundant family of termites, the Termitidae, evolved in African tropical forests. They have since colonised grassy biomes such as savannas. These open environments have more extreme conditions than tropical forests, notably wider extremes of temperature and lower precipitation levels and greater temporal fluctuations (of both annual and diurnal variation). These conditions are challenging for soft-bodied ectotherms, such as termites, to survive in, let alone become as ecologically dominant as termites have. Here, we quantified termite thermal limits to test the hypothesis that these physiological limits are wider in savanna termite species to facilitate their existence in savanna environments. We sampled termites directly from mound structures, across an environmental gradient in Ghana, ranging from wet tropical forest through to savanna. At each location, we quantified both the Critical Thermal Maxima (CTmax ) and the Critical Thermal Minima (CTmin ) of all the most abundant mound-building Termitidae species in the study areas. We modelled the thermal limits in two separate mixed-effects models against canopy cover at the mound, temperature and rainfall, as fixed effects, with sampling location as a random intercept. For both CTmax and CTmin , savanna species had significantly more extreme thermal limits than forest species. Between and within environments, areas with higher amounts of canopy cover were significantly associated with lower CTmax values of the termite colonies. CTmin was significantly positively correlated with rainfall. Temperature was retained in both models; however, it did not have a significant relationship in either. Sampling location explained a large proportion of the residual variation, suggesting there are other environmental factors that could influence termite thermal limits. Our results suggest that savanna termite species have wider thermal limits than forest species. These physiological differences, in conjunction with other behavioural adaptations, are likely to have enabled termites to cope with the more extreme environmental conditions found in savanna environments and facilitated their expansion into open tropical environments.