Michael Legge

Intensive exercise may preserve bone mass of the upper limbs in spinal cord injured males but does not retard demineralisation of the lower body

Study design: Cross-sectional study comparing a group of active spinal cord injured (SCI) males carefully matched for age, height, and weight with active able-bodied male controls.Objectives: To compare bone mass of the total body, upper and lower limbs, hip, and spine regions in active SCI and able-bodied individuals.Setting: Outpatient study undertaken in two centres in New Zealand.Methods: Dual energy X-ray absorptiometry (DEXA) scanning was used to determine bone mass. Questionnaires were used to ascertain total time spent in weekly physical activity for each individual. The criterion for entry into the study was regular participation in physical activity of more than 60 min per week, over and above that required for rehabilitation.Results: Seventeen SCI and their able-bodied controls met our required activity criterion. Bone mineral density (BMD) values of the total body and hip regions were significantly lower in the SCI group than in their controls (P=0.0001). Leg BMD and bone mineral content (BMC) were also significantly lower in the SCI group (P=0.0001). By contrast, lumbar spine BMD and arm BMD and BMC did not differ between the SCI and control groups. Arm BMD and BMC were greater (not significant) than the reference norms (LUNAR database) for both groups.Conclusion: Intensive exercise regimens may contribute to preservation of arm bone mass in SCI males, but does not prevent demineralisation in the lower body.Sponsorship: Funding provided by the DEXA Group Bone Health Dunedin, New Zealand and The Lamar Trust, Christchurch, New Zealand.

Mammalian Gene PEG10 Expresses Two Reading Frames by High Efficiency -1 Frameshifting in Embryonic-associated Tissues

Paternally expressed gene 10 (PEG10) is a mammalian gene that is essential for embryonic development in mice. The gene contains two overlapping open reading frames (ORF1 and ORF2) and is derived from a retroelement that acquired a cellular function. It is not known if both reading frames are required for PEG10 function. Synthesis of ORF2 would be possible only if programmed –1 frameshifting occurred during ORF1 translation. In this study the frameshifting activity of PEG10 was analyzed in vivo, and a potential role for ORF2 was investigated. Phylogenetic analysis demonstrated that PEG10 is highly conserved in therian mammals, with all species retaining the elements necessary for frameshifting as well as functional motifs in each ORF. The frameshift site of PEG10 was highly active in cultured cells and produced the ORF1-2 protein. In mice, endogenous ORF1 and an ORF1-2 frameshift protein were detected in the developing placenta and amniotic membrane from 9.5 days post-coitus through to term with a very high frameshift efficiency (>60%). Mutagenesis of the active site motif of a putative protease within ORF2 showed that this enzyme is active and participates in post-translational processing of PEG10 ORF1-2. Both PEG10 proteins were also detected in first trimester human placenta. By contrast, neither protein expression nor frameshifting was detected in adult mouse tissues. These studies imply that the ORF1-2 protein, synthesized utilizing the most efficient –1 frameshift mechanism yet documented in vivo, will have an essential function that is intrinsic to the importance of PEG10 in mammals.

Upright water-based exercise to improve cardiovascular and metabolic health: A qualitative review

Research regarding the benefits of exercise for cardiovascular and metabolic health is extensive and well-documented. However, weight-bearing exercise may not be suitable for individuals with orthopaedic or musculoskeletal limitations, excess adiposity or other medical conditions. Water-based exercise may provide an attractive alternative to land-based exercise for achieving improved health and fitness in these populations. Although swimming is a popular form of water-based exercise it requires specific skills and is often undertaken at intensities that may not be safely prescribed in patient populations. Therefore upright, water-based exercise has been suggested as a viable water-based alternative. However, surprisingly little is known about the effects of upright water-based exercise on improvements in cardiovascular and metabolic health. Limited evidence from water-based studies indicate that regular deep or shallow water exercise can exert beneficial effects on cardiorespiratory fitness, strength, and body fat distribution. However, the impacts of water-based exercise on lipid profile, bodyweight, and carbohydrate metabolism are still unclear. Further studies are warranted to establish the effects of non-swimming, water-based exercise on cardiometabolic risks in humans.

Maximal physiological responses between aquatic and land exercise in overweight women.

PURPOSE To investigate the maximal physiological responses between aquatic and land-based graded exercise tests in overweight women. METHODS Twenty healthy, overweight (body mass index (BMI) > or = 25 kg.m(-2)), Caucasian women (mean +/- SD; age 48 +/- 7 yr, BMI 30 +/- 4 kg.m(-2)) completed a deep water running (DWR) and treadmill walking (TMW) graded exercise test. Maximal responses during the DWR and TMW graded exercise tests were compared using paired t-tests. Comparisons were made in the incidence of achievement of maximal oxygen consumption (VO2max) criteria between DWR and TMW protocols. Criteria were a plateau in VO2 (change < 2.1 mL.kg.min(-1)), heart rate (HR) equal to or above the age-adjusted maximum, and respiratory exchange ratio (RER) > or = 1.15. RESULTS Maximal responses for VO2max (22.5 +/- 4.86 vs 27.7 +/- 4.73 mL.kg.min(-1)), HRmax (159 +/- 16 vs 170 +/- 12 bpm), and RER (1.03 +/- 0.06 vs 1.10 +/- 0.06) were significantly lower (P < 0.01) for the DWR test compared with the TMW test, respectively. Achievement of various VO2max criteria was demonstrated more consistently during the TMW test than the DWR test. CONCLUSION Maximal physiological responses of overweight women to DWR and TMW are significantly different but are comparable with other populations. As the maximal responses for DWR compared with TMW differ, the use of land-based criteria for VO2max is not recommended for a graded DWR exercise test.

The Effect of Water-Based Exercise on Glucose and Insulin Response in Overweight Women: A Pilot Study

OBJECTIVE The aim of this study was to investigate the effectiveness of a 12-week moderate intensity, water-based circuit-type training intervention on glucose and insulin responses in overweight women with normal or impaired glucose tolerance. METHODS Fifteen overweight women (body mass index [BMI] > 25 kg/m(2)) with normal glucose tolerance (NGT; n = 7) or impaired glucose tolerance (IGT; n = 8) were recruited for this study. All women completed a 12-week training intervention utilizing a combination of aerobic and resistance exercises in an aquatic environment, 3 days per week and 60 min per session at 70-75% mode-specific maximum heart rate. A standard 75-g oral glucose tolerance test (OGTT) was administered pre- and post-intervention, from which fasting and post-load plasma insulin and glucose levels were assessed. RESULTS Following the 12-week period, fasting insulin levels had decreased by 44% and 2-h glucose by 30.4% in the group with IGT. Waist circumference (WC) had decreased by 5.3% in this group at the end of the intervention. Only WC and waist-to-hip ratio (WHR) decreased (6.0% and 5.5%, respectively) following the intervention in the NGT group. CONCLUSIONS Moderate intensity, water-based circuit-type exercises appear to be an effective exercise modality to improve glucose and insulin response to a glucose challenge in overweight women with IGT.

Cultured peritoneal mesothelial cells exhibit apical primary cilia

This study examined primary cilia on cultured human and rabbit peritoneal mesothelial cells (PMC) and investigated factors that influence ciliary expression. Primary cilia were examined with indirect immunocytochemistry, laser scanning confocal microscopy and scanning electron microscopy. Ciliary expression was evaluated in cultures with or without l‐cysteine (0.25 mM) or exposure to Ca2+‐free Krebs—Ringer solution supplemented with EGTA, 0.5 mM. This treatment disrupted cell monolayer integrity. Cilia were counted and normalized to total cell counts using NIH image. Primary cilia were identified on both human and rabbit PMC. Cells treated with l‐cysteine expressed significantly more cilia compared with monolayers deprived of l‐cysteine. Exposure to Ca2+‐free Krebs—Ringer solution significantly reduced cilia (5.9±1.0%, n=7). Although ciliary expression could be augmented with l‐cysteine, approximately 60% of human PMC and 84% of rabbit PMC did not exhibit cilia. Together, these data show that monolayers of PMC express apical cilia that can be augmented with l‐cysteine, independently of increased cell density.

Proteomic Analysis of Aortae from Human Lipoprotein(a) Transgenic Mice Shows an Early Metabolic Response Independent of Atherosclerosis

Background Elevated low density lipoprotein (LDL) and lipoprotein(a) are independent risk factors for the development of atherosclerosis. Using a proteomic approach we aimed to determine early changes in arterial protein expression in transgenic mice containing both human LDL and lipoprotein(a) in circulation. Methods and Results Plasma lipid analyses showed the lipoprotein(a) transgenic mice had significantly higher lipid levels than wildtype, including a much increased LDL and high density lipoprotein (HDL) cholesterol. Analysis of aortae from lipoprotein(a) mice showed lipoprotein(a) accumulation but no lipid accumulation or foam cells, leaving the arteries essentially atherosclerosis free. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 34 arterial proteins with significantly altered abundance (P<0.05) in lipoprotein(a) transgenic mice compared to wildtype including 17 that showed a ≥2 fold difference. Some proteins of interest showed a similarly altered abundance at the transcript level. These changes collectively indicated an initial metabolic response that included a down regulation in energy, redox and lipid metabolism proteins and changes in structural proteins at a stage when atherosclerosis had not yet developed. Conclusions Our study shows that human LDL and lipoprotein(a) promote changes in the expression of a unique set of arterial proteins which may be early indicators of the metabolic disturbances preceding atherosclerosis.

Amino acid transport system L activity in developing mouse ovarian follicles

BACKGROUND Little is known about metabolic processes in the developing ovarian follicle. Using mouse ovarian follicles, we investigated uptake of L-leucine by follicles at varying stages of maturity in the presence of insulin-like growth factor (IGF)-1. METHODS Mouse ovarian follicles were cultured in vitro for 5 days in increasing concentrations of IGF-1, and follicle diameter and atresia measured as endpoints for growth. Uptake of (3)H-leucine was measured in follicles at different stages of development. In optimal IGF-1-mediated growth conditions, competitive inhibition of (3)H-leucine uptake by 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH), a non-metabolizable substrate analogue of L-leucine, was performed to demonstrate specificity of influx, via system L transporters. To test whether uptake rates were dependent on intracellular amino acid availability, follicles from in vitro cultures were pre-treated with L-phenylalanine prior to (3)H-leucine uptake. RESULTS Follicle development (P< 0.001) and survival (P< 0.001) increased with IGF-1 treatment. As pre-antral follicles progressed to late antral stage, we observed an increase in L-leucine uptake, which was reduced in pre-ovulatory follicles. BCH decreased L-leucine uptake rates in early antral (P< 0.05), antral (P< 0.001) and pre-ovulatory follicles (P< 0.01). L-leucine influx increased in follicles preloaded with phenylalanine (trans-stimulation). In follicles lacking free intracellular amino acids (zero-trans suppression), uptake rate was reduced (P< 0.05). CONCLUSIONS These results demonstrate, for the first time, evidence of specific system L amino acid transport in intact, mouse ovarian follicles and profile L-leucine uptake during folliculogenesis. A better understanding of ovarian follicle metabolic pathways is necessary for improved in vitro maturation as well as determining the impact of altered metabolism on fertility.

Synthesis of Early Pregnancy Factor Using Red Deer (Cervus elaphus) as a Delayed Implantation Model

Purpose: This study measured serum early pregnancy factor (EPF) in pregnant red deer (Cervus elaphus) and ascertained whether EPF synthesis is associated with implantation.Methods: Serial serum samples were taken from mated hinds up to 42 days postconception and analyzed for EPF activity using the rosette inhibition test. EPF activity was then correlated with calving records and stages of preimplantation development.Results: EPF was detected in all pregnant animals, with a twin pregnancy giving increased EPF activity. Three animals gave an EPF response following fertilization but failed to continue beyond the preimplantation embryo stage. The increase in EPF synthesis previously associated with implantation in other mammals occurred at the blastocyst stage in red deer.Conclusions: EPF synthesis in red deer (Cervus elaphus) is consistent with the preimplantation period, as occurs in other mammals. However, the second phase of the biphasic increase in early pregnancy factor production is associated with blastocyst formation, not implantation.

Formaldehyde scavenging from peritoneal dialysis solutions using reduced aminothiol compounds

Background:  Aldehydes were identified in clinical solutions, including peritoneal dialysis (PD) and cryoprotection solutions, which were used to freeze cells, tissues and embryos. Aldehydes are associated with increased cellular injury and may contribute to peritoneal membrane damage that occurs in patients on peritoneal dialysis. Recently, it was demonstrated that aldehydes could be ‘scavenged’ from these solutions by using aminothiol compounds. Although aldehydes were removed during the scavenging process, the kinetics of scavenging and the products formed were not characterized.