The Stature of Boys Is Inversely Correlated to the Levels of Their Sertoli Cell Hormones: Do the Testes Restrain the Maturation of Boys?

The testes of preadolescent boys appear to be dormant, as they produce only trace levels of testosterone [1]. However, they release supra-adult levels of Müllerian Inhibiting Substance (MIS, anti-Müllerian hormone) and lesser levels of inhibin B (InhB), for unknown reasons [2], [3]. Boys have a variable rate of maturation, which on average is slower than girls. The height of children relative to their parents is an index of their maturity [4], [5]. We report here that a boy's level of MIS and InhB is stable over time and negatively correlates with his height and his height relative to his parent's height. This suggests that boy's with high levels of MIS and InhB are short because they are immature, rather than because they are destined to be short men. The levels of MIS and InhB in the boys did not correlate with known hormonal modulators of growth, and were additive with age and the growth hormone/IGF1 axis as predictors of a boy's height. If MIS and InhB were causal regulators of maturity, then the inter-boy differences in the levels of these hormone produces variation in maturation equivalent to 18-months of development. MIS and InhB may thus account for most of the variation in the rate of male development. If boys lacked these hormones, then an average 5-year-old boy would be over 5 cm taller than age-matched girls, making boys almost as dimorphic as men, for height. This indicates that boys have a high growth potential that is initially suppressed by their testes. The concept of the childhood testes suppressing an adult male feature appears paradoxical. However, the growth of children requires intergenerational transfer of nutrients. Consequently, the MIS/InhB slowing of male growth may have been historically advantageous, as it would minimizes any sex bias in the maternal cost of early child rearing

Regional variation and determinants of vitamin D status in sunshine-abundant Thailand

<p>Abstract</p> <p>Background</p> <p>Vitamin D insufficiency is highly prevalent. Most of the studies concerning vitamin D status were generated from countries situated at temperate latitudes. It is less clear what the extent of vitamin D insufficiency is in countries situated in the tropics and how geographical regions within country would affect vitamin D status. In the present study, we investigated vitamin D status in Thais according to geographical regions and other risk factors.</p> <p>Methods</p> <p>Subjects consisted of 2,641 adults, aged 15 - 98 years, randomly selected from the Thai 4th National Health Examination Survey (2008-9) cohort. Serum 25 hydroxyvitamin D were measured by liquid chromatography/tandem mass spectrometry. Data were expressed as mean ± SE.</p> <p>Results</p> <p>Subjects residing in Bangkok, the capital city of Thailand, had lower 25(OH)D levels than other parts of the country (Bangkok, central, northern, northeastern and southern regions: 64.8 ± 0.7, 79.5 ± 1.1, 81.7 ± 1.2, 82.2 ± 0.8 and 78.3 ± 1.3 nmol/L, respectively; <it>p </it>< 0.001). Within each region, except for the northeastern part of the country, subjects living inside municipal areas had lower circulating 25(OH)D (central, 77.0 ± 20.9 nmol/L vs 85.0 ± 22.1 nmol/L, <it>p </it>< 0.001; north 79.3 ± 22.1 nmol/L vs 86.8 ± 21.8 nmol/L, <it>p </it>< 0.001; northeast 84.1 ± 23.3 nmol/L vs 87.3 ± 20.9 nmol/L, <it>p </it>= 0.001; south, 76.6 ± 20.5 nmol/L vs 85.2 ± 24.7 nmol/L, <it>p </it>< 0.001). Overall, the prevalence of vitamin D insufficiency was 64.6%, 46.7%, and 33.5% in Bangkok, municipal areas except Bangkok, and outside municipal area in other parts of the country, respectively. In addition, the prevalence of vitamin D insufficiency according to geographical regions was 43.1%, 39.1%, 34.2% and 43.8% in the central, north, northeast and south, respectively. After controlling for covariates in multiple linear regression analysis, the results showed that low serum 25(OH)D levels were associated with being female, younger age, living in urban and Bangkok.</p> <p>Conclusions</p> <p>Vitamin D insufficiency is common and varies across geographical regions in Thailand.</p

Factors associated with serum 25-hydroxyvitamin D concentrations in older people in Europe: the EUREYE study.

BACKGROUND/OBJECTIVES: We aimed to describe serum 25-hydroxyvitamin D (25OHD) concentrations in older Europeans and to investigate associations between 25OHD and lifestyle factors, including dietary intake and supplement use. SUBJECTS/METHODS: Men and women aged ≥ 65 years were recruited from seven centres across north to south Europe. Serum 25OHD2 and 25OHD3 concentrations were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 4495 samples and total 25OHD (25OHD2 + 25OHD3) was adjusted for season of blood collection. RESULTS: The mean (25th, 75th quartile) of seasonally adjusted 25OHD was 46 (34, 65) nmol/L, with the highest concentration of 25OHD in Bergen [61 (49, 79) nmol/L], and the lowest in Paris [36 (24, 57) nmol/L)]. Vitamin D deficiency (25-50 nmol/L) and vitamin D insufficiency (50-75 nmol/L) were found in 41 and 33% of the population, respectively. In multivariable analysis controlled for confounders, seasonally adjusted 25OHD concentrations were significantly (p < 0.05) lower in smokers and participants with self-reported diabetes and higher with increasing dietary vitamin D, and supplement use with fish liver oil, omega-3, and vitamin D. Additionally, in further analysis excluding Bergen, 25OHD was associated with higher intakes of oily fish and increasing UVB exposure. We observed low concentrations of 25OHD in older people in Europe. CONCLUSIONS: Our findings of the higher 25OHD concentrations in supplement users (omega-3 fish oil, fish liver oil, vitamin D) add to current recommendations to reduce vitamin D deficiency. We were unable to fully assess the role of dietary vitamin D as we lacked information on vitamin D-fortified foods

Evaluation of hindered amine light stabilisers and their N-chlorinated derivatives as antibacterial and antifungal additives for thermoset surface coatings

© 2016 Elsevier B.V. N-Halogenated amines or ‘halamines’ have attracted recent attention as potential biocides for materials and surface coatings application. Facile N-chlorination of the hindered amine light stabiliser (HALS) Tinuvin®770, bis-(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, was achieved by reaction with sodium dichloroisocyanurate. The chlorinated product was incorporated into a polyester-based paint formulated for coil coating, applied to test panels and subjected to high temperature curing conditions characteristic of the coil coating process (55 s at 262 °C). Rapid detection of N-chlorinated Tinuvin®770 in the cured coating was confirmed, using liquid extraction surface analysis-mass spectrometry, by the characteristic fragmentation patterns of the halamines observed upon collision-induced dissociation. Antimicrobial activity of the coating was determined by testing against the bacterium Pseudomonas aeruginosa and the fungus Cladosporium sp., two organisms that are known to colonise both internal and external surfaces in building and cladding applications. The activity of HALS and halamine containing coatings were compared against a commercial product containing an antimicrobial additive as well as control surfaces without additives. Significant activity against the bacterium, but not against the fungus was demonstrated for the parent HALS and halamine containing coatings. The possibility of regeneration of the halamines was also tested and confirmed by mass spectrometry, post-chlorination of samples showed no significant differences in activity between corresponding pairs of samples