Flight of the Vampire: Ontogenetic Gait-Transition in \u3cem\u3eVampyroteuthis Infernalis\u3c/em\u3e (Cephalopoda: Vampyromorpha)

Vampyroteuthis infernalis is a cosmopolitan cephalopod that lives in the oxygen minimum layer between 600 and 800 m depth. Morphometric and physiological studies have indicated that V. infernalis has little capacity for jet propulsion and has the lowest metabolic rate ever measured for a cephalopod. Because fin swimming is inherently more efficient than jet propulsion, some of the reduction in energy usage relative to other cephalopods may result from the use of fins as the primary means of propulsion. V. infernalis undergoes a rapid metamorphosis which consists of changes in the position, size and shape of the fins. This suggests that there are changes in the selective factors affecting locomotion through ontogeny. The present study describes these changes in relation to models for underwater ‘flight’. Citrate synthase (CS) and octopine dehydrogenase (ODH) activities, indicative of aerobic and anaerobic metabolism, respectively, were measured in fin, mantle and arm tissue across a range of body size of four orders of magnitude. The low enzymatic activities in both posterior and anterior fin tissue and the relatively high activity in mantle muscle prior to metamorphosis indicate that jet propulsion using mantle contraction is the primary means of propulsion in juvenile V. infernalis. The increase in CS activity with size after metamorphosis suggests an increased use of the fins for lift-based propulsion. Fin swimming appears to be the primary means of propulsion at all adult sizes. The negative allometry of CS activity in mantle and arm muscle is consistent with the scaling of oxygen consumption previously measured for V. infernalis and with the scaling of aerobic metabolism observed in most animals. The unusual positive allometry of fin muscle CS activity suggests that the use of fins is either relatively more important or more costly in larger animals. Positive scaling of ODH activity in all tissues suggests that fin propulsion, jet propulsion and medusoid ‘bell-swimming’ are all important for burst escape responses. Enzyme activities in Cirrothauma murrayi are consistent with finswimming observed from submersibles, while those in Opisthoteuthis californiana suggest a strong reliance on medusoid swimming using the arms. The transition from jet propulsion to paired-fin ‘flight’ with increasing body size in Vampyroteuthis infernalis appears functionally to be an ontogenetic ‘gait-transition’

Progression of myopathology in Kearns-Sayre syndrome

We report on the progression of myopathology by comparing two biopsies from a patient with a Kearns-Sayre-Syndrome. The first biopsy was taken in 1979 and showed 10% ragged-red fibers. Myopathic changes were slight including internal nuclei and fiber splitting in 10% of the fibers. Electron microscopy revealed typical mitochondrial abnormalities with regard to number and shape. In 1989 a second biopsy was performed for an extended analysis of mitochondrial DNA. This time less than 5% of all fibers were ragged-red. Severe myopathic changes could be detected which so far has rarely been reported in mitochondrial cytopathy

Does combined osteopenia/osteoporosis and sarcopenia confer greater risk of falls and fracture than either condition alone in older men? The Concord Health and Ageing in Men Project

Background It is unclear whether older men with osteopenia/osteoporosis and sarcopenia (so-called osteosarcopenia) are at greater risk of falls and fractures than those with either condition alone. Methods One thousand five hundred seventy-five community-dwelling men aged ≥70 years had appendicular lean mass, total hip and lumbar spine bone mineral density determined by dual-energy x-ray absorptiometry, and completed hand grip strength and gait speed tests. Osteopenia/osteoporosis was defined as a T-score at any site ≤−1.0 SD. Sarcopenia was defined using the European Working Group on Sarcopenia algorithm. Participants were contacted every 4 months for 6 ± 2 years to ascertain incident fractures (confirmed by radiographic reports) and for 2 years for incident falls. Results Prevalence of osteosarcopenia was 8%, while 34% of participants had osteopenia/osteoporosis alone and 7% had sarcopenia alone. Men with osteosarcopenia had significantly increased fall (incidence rate ratio: 1.41; 95% confidence interval [CI]: 1.02 to 1.95) and fracture risk (hazard ratio: 1.87; 95% CI: 1.07 to 3.26) compared with men with neither osteopenia/osteoporosis nor sarcopenia. There was no statistical interaction between osteopenia/osteoporosis and sarcopenia, and falls and fracture risk were not different for osteosarcopenia compared with either condition alone (all p > .05). Conclusions Community-dwelling older men with combined osteopenia/osteoporosis and sarcopenia do not have increased falls and fracture risk compared with those with either condition. Further research is required to clarify whether the term “osteosarcopenia” has any meaning above and beyond either term alone and therefore potential clinical utility for falls and fracture prediction.NHMRC (project grant number 301916) and the Ageing and Alzheimer’s Institute. D.Scott is supported by a NHRMC Career Development Fellowship (GNT1123014

Metabolic and skeletal homeostasis are maintained in full locus GPRC6A knockout mice

Abstract The G protein-coupled receptor class C, group 6, subtype A (GPRC6A) is suggested to have a physiological function in glucose and bone metabolism, although the precise role lacks consensus due to varying findings in different knockout (KO) mouse models and inconsistent findings on the role of osteocalcin, a proposed GPRC6A agonist. We have further characterized a full locus GPRC6A KO model with respect to energy metabolism, including a long-term high-dose glucocorticoid metabolic challenge. Additionally, we analyzed the microarchitecture of tibiae from young, middle-aged and aged GPRC6A KO mice and wildtype (WT) littermates. Compared to WT, vehicle-treated KO mice presented with normal body composition, unaltered insulin sensitivity and basal serum insulin and glucose levels. Corticosterone (CS) treatment resulted in insulin resistance, abnormal fat accrual, loss of lean mass and suppression of serum osteocalcin levels in both genotypes. Interestingly, serum osteocalcin and skeletal osteocalcin mRNA levels were significantly lower in vehicle-treated GPRC6A KO mice compared to WT animals. However, WT and KO age groups did not differ in long bone mass and structure assessed by micro-computed tomography. We conclude that GPRC6A is not involved in glucose metabolism under normal physiological conditions, nor does it mediate glucocorticoid-induced dysmetabolism in mice. Moreover, GPRC6A does not appear to possess a direct, non-compensable role in long bone microarchitecture under standard conditions

Evaluating Calculated Free Testosterone as a Predictor of Morbidity and Mortality Independent of Testosterone for Cross-sectional and 5-Year Longitudinal Health Outcomes in Older Men: The Concord Health and Ageing in Men Project

To determine whether calculated free testosterone (cFT) provides prognostic information independent of serum T for predicting morbidity and mortality in older men in cross-sectional and 5-year longitudinal analyses. We studied men aged ≥70 years at baseline (n = 1,705), 2-year and 5-year measuring serum T (liquid chromatography-mass spectrometry), SHBG (immunoassay), cFT (an assumption-free empirical formula) together with 24 morbidity and 4 mortality outcomes. For cross-sectional and longitudinal analyses we employed a joint prediction model using generalized estimating equation models adjusted for age, smoking, comorbidities, and body mass index (BMI) with men having both normal T and normal cFT as referent group. Most morbidity and mortality outcomes were predicted by a combination of low T and cFT (LL). By contrast, only a single morbidity outcome in cross-sectional and none in longitudinal analysis was predicted by low T/normal cFT (LN) or normal T/low cFT (NL) without significant LL associations (isolated discordance). While for the few outcomes that predicted morbidity in men with discordances (LN or NL), these predictions only occurred when LL was also significant. Hence, for morbidity or mortality prediction in older men, discordance between cFT and T is unusual and isolated discordance is rare, so that cFT provides minimal independent prognostic information over serum T.NHMRC, Sydney Medical School Foundation, and Ageing and Alzheimer’s Institute

Association between pain and the frailty phenotype in older men: longitudinal results from the Concord Health and Ageing in Men Project (CHAMP)

Objectives to determine whether pain increases the risk of developing the frailty phenotype and whether frailty increases the risk of developing chronic or intrusive pain, using longitudinal data. Design/Setting longitudinal data from the Concord Health and Ageing in Men Project (CHAMP), a prospective population based cohort study. Participants a total of 1,705 men aged 70 years or older, living in an urban area of New South Wales, Australia. Measurements data on the presence of chronic pain (daily pain for at least 3 months), intrusive pain (pain causing moderate to severe interference with activities) and the criteria for the Cardiovascular Health Study (CHS) frailty phenotype were collected in three waves, from January 2005 to October 2013. Data on age, living arrangements, education, smoking status, alcohol consumption, body mass index, comorbidities, cognitive function, depressive symptoms and history of vertebral or hip fracture were also collected and included as covariates in the analyses. Results a total of 1,705 participants were included at baseline, of whom 1,332 provided data at the 2-year follow-up and 940 at the 5-year follow-up. Non-frail (robust and pre-frail) men who reported chronic pain were 1.60 (95% confidence interval (CI): 1.02–2.51, P = 0.039) times more likely to develop frailty at follow-up, compared to those with no pain. Intrusive pain did not significantly increase the risk of future frailty. Likewise, the frailty status was not associated with future chronic or intrusive pain in the adjusted analysis. Conclusions the presence of chronic pain increases the risk of developing the frailty phenotype in community-dwelling older men.NHMRC, The Ageing and Alzheimer's Institut

Community-dwelling men with dementia are at high risk of hip but not any other fracture: The Concord Health and Ageing in Men Project

Aim The aim of the present longitudinal study of community‐dwelling older men was to examine the association between cognitive status at baseline, and falls, fractures and bone loss over time. Methods In the Concord Health and Aging in Men Project, 1705 community‐dwelling men aged 70–97 years had detailed baseline clinical assessment of cognitive status (dementia, mild cognitive impairment [MCI] and normal cognition), as well as depression, physical activity, neuromuscular function, health status, sociodemographics, comorbidities, medication use and serum 25 hydroxyvitamin D, 1,25 dihydroxyvitamin D and parathyroid hormone levels. During a mean follow‐up period of 6 years, participants were contacted 4‐monthly to ascertain incident falls and fractures, the latter being confirmed by radiographic reports. Bone mineral density was measured by dual X‐ray absorptiometry at multiple time‐points. Results At baseline, 120 men were assessed to have MCI and 93 men to have dementia. Over time, there were 162 first incident fractures, including 43 hip and 32 vertebral fractures. In univariate models, baseline dementia, but not MCI, predicted an increased incidence of hip fracture (HR 6.95, 95% CI 3.47–13.96), but not vertebral (HR 2.26, 95% CI 0.79–6.46) or non‐hip non‐vertebral fracture (HR 0.73, 95% CI 0.27–1.99). The strong risk of hip fractures associated with dementia remained after accounting for potential confounders (HR 4.44, 95% CI 1.97–9.98). In multivariate analyses, dementia (incidence rate ratio 2.26, 95% CI 1.70–2.99), but not MCI, was associated with an increased risk of falls compared with normal cognition. There was no association between baseline dementia and change in bone mineral density. Conclusions Older men with dementia, but not MCI, have a greater tendency to fall and sustain hip fractures, but not any other types of fractures.NHMRC, Ageing and Alzheimer's Institute, Sydney Medical School Foundatio

Relationship between serum testosterone and fracture risk in men: a comparison of RIA and LC-MS/MS

BACKGROUND: Serum testosterone can be measured byLC-MS/MS and RIA. We investigated whether the testosterone–fracture relationship was affected by the method of measurement. METHODS: We measured total testosterone (TT) by LCMS/MS (TTLC-MS/MS) and RIA (TTRIA) in serum samples collected from 602 men whose incident fractures had been continuously ascertained by x-ray reports from 1989 to 2010. We measured bone mineral density (BMD) by dual-energy x-ray absorptiometry. The association between TT and fracture risk was assessed by the Cox proportional hazards model, taking into account the effect of age and BMD. CONCLUSIONS: The concordance between LC-MS/MS and RIA in the measurement of serum TT was moderate. Moreover, the magnitude of association between testosterone and fracture risk in older men was largely unaffected by the method of measurement. © 2015 American Association for Clinical Chemistr