Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.

BACKGROUNDMore than 20 years ago, it was hypothesized that exposure to prenatal and early postnatal environmental xenobiotics with the potential to disrupt endogenous hormone signaling might be on the causal path to cryptorchidism, hypospadias, low sperm count and testicular cancer. Several consensus statements and narrative reviews in recent years have divided the scientific community and have elicited a call for systematic transparent reviews. We aimed to fill this gap in knowledge in the field of male reproductive disorders.OBJECTIVE AND RATIONALEThe aim of this study was to systematically synthesize published data on the risk of cryptorchidism, hypospadias, low sperm counts and testicular cancer following in utero or infant exposure to chemicals that have been included on the European Commission's list of Category 1 endocrine disrupting chemicals defined as having documented adverse effects due to endocrine disruption in at least one intact organism.SEARCH METHODSA systematic literature search for original peer reviewed papers was performed in the databases PubMed and Embase to identify epidemiological studies reporting associations between the outcomes of interest and exposures documented by biochemical analyses of biospecimens including maternal blood or urine, placenta or fat tissue as well as amnion fluid, cord blood or breast milk; this was followed by meta-analysis of quantitative data.OUTCOMESThe literature search resulted in 1314 references among which we identified 33 papers(28 study populations) fulfilling the eligibility criteria. These provided 85 risk estimates of links between persistent organic pollutants and rapidly metabolized compounds (phthalates and Bisphenol A) and male reproductive disorders. The overall odds ratio (OR) across all exposures and outcomes was 1.11 (95% CI 0.91–1.35). When assessing four specific chemical subgroups with sufficient data for meta-analysis for all outcomes, we found that exposure to one of the four compounds, p,p′-DDE, was related to an elevated risk: OR 1.35 (95% CI 1.04–1.74). The data did not indicate that this increased risk was driven by any specific disorder.WIDER IMPLICATIONSThe current epidemiological evidence is compatible with a small increased risk of male reproductive disorders following prenatal and postnatal exposure to some persistent environmental chemicals classified as endocrine disruptors but the evidence is limited. Future epidemiological studies may change the weight of the evidence in either direction. No evidence of distortion due to publication bias was found, but exposure–response relationships are not evident. There are insufficient data on rapidly metabolized endocrine disruptors and on specific exposure–outcome relations. A particular data gap is evident with respect to delayed effects on semen quality and testicular cancer. Although high quality epidemiological studies are still sparse, future systematic and transparent reviews may provide pieces of evidence contributing to the narrative and weight of the evidence assessments in th...

Daily intake of artificially sweetened soft drinks may increase the risk of preterm delivery. Further studies are needed to reject or confirm these findings.

M, Langberg H. Effect of administration of oral contraceptives in vivo on collagen synthesis in tendon and muscle connective tissue in young women. J Appl Physiol 106: 1435-1443, 2009. First published October 9, 2008 doi:10.1152/japplphysiol.90933.2008Women are at greater risk than men for certain kinds of diseases and injuries, which may at least partly be caused by sex hormonal differences. We aimed to test the influence of estradiol in vivo on collagen synthesis in tendon, bone, and muscle. Two groups of young, healthy women similar in age, body composition, and exercisetraining status were included. The two groups were either habitual users of oral contraceptives exposed to a high concentration of synthetic estradiol and progestogens (OC, n ϭ 11), or non-OC-users tested in the follicular phase of the menstrual cycle characterized by low concentrations of estradiol and progesterone (control, n ϭ 12). Subjects performed 1 h of one-legged kicking exercise. The next day collagen fractional synthesis rates (FSR) in tendon and muscle connective tissue were measured after a flooding dose of [ 13 C]proline followed by biopsies from the patellar tendon and vastus lateralis in both legs. Simultaneously, microdialysis catheters were inserted in vastus lateralis and in front of the patellar tendon for measurement of insulin-like growth factor I (IGF-I) and its binding proteins. Serum NH 2-terminal propeptide of type I collagen (PINP) and urine COOHterminal telopeptides of type-I collagen (CTX-I) were measured as markers for bone synthesis and breakdown, respectively. Tendon FSR and PINP were lower in OC compared with control. An increase in muscle collagen FSR postexercise was only observed in control (P Ͻ 0.05). Furthermore, the results indicate a lower bioavailability of IGF-I in OC. In conclusion, synthetic female sex hormones administered as OC had an inhibiting effect on collagen synthesis in tendon, bone, and muscle connective tissue, which may be related to a lower bioavailability of IGF-I. estrogen; exercise; insulin-like growth factor I; ethinyl estradiol; bone COLLAGEN is the most abundant protein in the human body and comprises a very high fraction of the tissue organic mass in bone (90%), tendon (60 -85%), ligament (70%), and intramuscular connective tissue (ϳ30% and up to 90%) (31, 57). The frequency of several diseases linked to collagen-rich tissue seems to be biased by sex (30,34,36,65). Furthermore, women are at a greater risk than men for sustaining certain kinds of soft tissue sports injuries (7, 24, 26). Several epidemiological studies have shown that women have up to six times greater risk of anterior cruciate ligament (ACL) ruptures than activity-matched men (24). It has been suggested that sex hormones may influence collagen turnover, tissue composition, and biomechanical properties of the tissues, which in part may explain sex-specific differences in risk (24). In support of this, tendon collagen synthesis is lower in women compared with men at rest and after exercise (47). In addition, a lower p...

A novel method using solution-processed ultrathin chemically derived graphene films as soft top contacts for the non-destructive fabrication of molecular junctions is demonstrated. We believe this protocol will greatly enrich the solid-state test beds for molecular electronics due to its low-cost, easy-processing and flexible nature.

Sarcopenia is a well-known phenomenon in elderly individuals and resistance exercise together with sufficient amino acid (AA) availability has proved to be a counteractive implement. However, the source of AA and supplement timing require further investigation. The objective was to compare muscle protein synthesis (MPS) to intakes of whey and caseinate after heavy resistance exercise in healthy elderly individuals, and, furthermore, to compare the timing effect of caseinate intake. Twenty-four elderly men and women (mean ± SEM; 68 ± 1 years) were randomized to one of four groups: caseinate intake before exercise (CasPre), caseinate intake immediately after exercise (CasPost), whey intake immediately after exercise (Whey), or intake of a non-caloric control drink (Control). Muscle myofibrillar and collagen fractional synthesis rates (FSR) were measured by a primed continuous infusion of L-[1-(13) C]leucine using labeled proteins during a 6-h recovery period. No differences were observed in muscle myofibrillar and collagen FSR with Whey (0.09 ± 0.01%/h) compared with CasPost (0.09 ± 0.003%/h), and it did not differ between CasPre (0.10 ± 0.01%/h) and CasPost. MPS does not differ with whey and caseinate feeding immediately after heavy resistance exercise in elderly individuals, and MPS is similar with caseinate ingestion before and after exercise.

Background: Vitamin D is obtained from dietary sources and synthesized in the skin during exposure to ultraviolet B radiation in sunlight. During pregnancy, vitamin D is transported from mother to fetus through the placenta in the form of 25-hydroxyvitamin D [25(OH)D]. There is evidence that vitamin D influences neuronal differentiation, endocrine functions, and fetal brain growth. Animal studies indicate alterations in the offspring brain as a consequence of vitamin D deficiency during pregnancy. In humans, maternal vitamin D insufficiency has been linked to impaired child language development. Using data from a prebirth cohort with up to 22 years of follow-up, we examined the association of vitamin D status with proxies of offspring neurodevelopmental outcomes. During 1988-1989, pregnant women were recruited for the DaFO88 cohort (n = 965) in Aarhus, Denmark. Maternal concentrations of 25(OH)D were quantified in serum from week 30 of gestation via the LC-MS/MS method (n = 850). Offspring were followed up through national registries until the age of 22 years. We evaluated the association of the maternal concentration of 25(OH)D with offspring neurodevelopmental outcomes defined as first admission diagnosis or prescription of medication for (1) ADHD, (2) depression, and (3) scholastic achievement based on the mean grade on standardized written examinations in the 9th grade (final exams after 10 years of compulsory school in Denmark). Key Messages: Maternal concentrations of 25(OH)D were higher compared to current levels (median 76 nmol/l; 5th to 95th percentiles 23-152). There was a direct association between maternal vitamin D status and offspring depression (p_trend = 0.01); for ADHD there was no association. Scholastic achievement was slightly higher for offspring of mothers with a vitamin D status in the range of >50-125 nmol/l, but this nonlinear association was not statistically significant. Conclusions: Our analyses based on biomarker measurement of 25(OH)D from a cohort of 850 pregnant women combined with long-term follow-up showed no support for a beneficial fetal programming effect of vitamin D status with regard to behavioral and affective disorders and scholastic achievement.

A new type of solid-state molecular junction is introduced, which employs reduced graphene oxide as a transparent top contact that permits a self-assembled molecular monolayer to be photoswitched in situ, while simultaneously enabling charge-transport measurements across the molecules. The electrical switching behavior of a less-studied molecular switch, dihydroazulene/vinylheptafulvene, is described, which is used as a test case.