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

Enhanced Gene Delivery Mediated by Low Molecular Weight Chitosan/DNA Complexes: Effect of pH and Serum

This study was designed to systematically evaluate the influence of pH and serum on the transfection process of chitosan-DNA complexes, with the objective of maximizing their efficiency. The hydrodynamic diameter of the complexes, measured by dynamic light scattering (DLS), was found to increase with salt and pH from 243 nm in water to 1244 nm in PBS at pH 7.4 and aggregation in presence of 10% serum. The cellular uptake of complexes into HEK 293 cells assessed by flow cytometry and confocal fluorescent imaging was found to increase at lower pH and serum. Based on these data, new methodology were tested and high levels of transfection (>40%) were achieved when transfection was initiated at pH 6.5 with 10% serum for 8-24 h to maximize uptake and then the media was changed to pH 7.4 with 10% serum for an additional 24-40 h period. Cytotoxicity of chitosan/DNA complexes was also considerably lower than Lipofectamine. Our study demonstrates that the evaluation of the influence of important parameters in the methodology of transfection enables the understanding of crucial physicochemical and biological mechanisms which allows for the design of methodologies maximising transgene expression

Brazilian Consensus on Photoprotection

Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of nonmelanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection

Vitamin D Deficiency and Its Health Consequences in Africa

Africa is heterogeneous in latitude, geography, climate, food availability, religious and cultural practices, and skin pigmentation. It is expected, therefore, that prevalence of vitamin D deficiency varies widely, in line with influences on skin exposure to UVB sunshine. Furthermore, low calcium intakes and heavy burden of infectious disease common in many countries may increase vitamin D utilization and turnover. Studies of plasma 25OHD concentration indicate a spectrum from clinical deficiency to values at the high end of the physiological range; however, data are limited. Representative studies of status in different countries, using comparable analytical techniques, and of relationships between vitamin D status and risk of infectious and chronic diseases relevant to the African context are needed. Public health measures to secure vitamin D adequacy cannot encompass the whole continent and need to be developed locally

Utilization and prescribing patterns of direct oral anticoagulants

Maegan M Whitworth,1 Krystal K Haase,1 David S Fike,1 Ravindra M Bharadwaj,2 Rodney B Young,3 Eric J MacLaughlin1,4 1Department of Pharmacy Practice, Texas Tech University Health Sciences Center (TTUHSC) School of Pharmacy, 2Department of Internal Medicine, 3Department of Family and Community Medicine, 4Departments of Family Medicine and Internal Medicine, TTUHSC School of Medicine, Amarillo, TX, USA Background: Scant literature exists evaluating utilization patterns for direct oral anticoagulants (DOACs). Objectives: The primary objective was to assess DOAC prescribing in patients with venous thromboembolism (VTE) and nonvalvular atrial fibrillation (NVAF) in outpatient clinics. Secondary objectives were to compare utilization between family medicine (FM) and internal medicine (IM) clinics, characterize potentially inappropriate use, and identify factors associated with adverse events (AEs). Methods: This was a retrospective cohort study of adults with NVAF or VTE who received a DOAC at FM or IM clinics between 10/19/2010 and 10/23/2014. Descriptive statistics were utilized for the primary aim. Fisher’s exact test was used to evaluate differences in prescribing using an adapted medication appropriateness index. Logistic regression evaluated factors associated with inappropriate use and AEs. Results: One-hundred twenty patients were evaluated. At least 1 inappropriate criterion was met in 72 patients (60.0%). The most frequent inappropriate criteria were dosage (33.0%), duration of therapy (18.4%), and correct administration (18.0%). Apixaban was dosed inappropriately most frequently. There was no difference in dosing appropriateness between FM and IM clinics. The odds of inappropriate choice were lower with apixaban compared to other DOACs (odds ratio [OR]=0.088; 95% confidence interval [CI] 0.008–0.964; p=0.047). Twenty-seven patients (22.5%) experienced an AE while on a DOAC, and the odds of bleeding doubled with each inappropriate criterion met (OR=1.949; 95% CI 1.190–3.190; p=0.008). Conclusion: Potentially inappropriate prescribing of DOACs is frequent with the most common errors being dosing, administration, and duration of therapy. These results underscore the importance of prescriber education regarding the appropriate use and management of DOACs. Keywords: rivaroxaban, dabigatran, apixaban, atrial fibrillation, venous thromboembolism, medication errors&nbsp