Context. Various data suggest seasonal variation in testosterone levels. However, previous studies are limited by their size or by variability in baseline characteristics. Objectives. The aim of the study was to evaluate in a large cohort of males with a wide range of age, metabolic status, and coexistent morbidities whether month of blood test performance was associated with total and bioavailable testosterone levels independent of age, body mass index (BMI), existing cardiovascular disease (CVD), and CVD risk factors. Methods. Cross-sectional study includes data from computerized medical records of 27,328 men aged 20–70, treated by the largest healthcare organization in Israel, who had undergone testosterone measurement. In 7,940 subjects with available sex-hormone-binding globulin levels, bioavailable testosterone was calculated. Results. Total and bioavailable testosterone levels gradually decreased with age and BMI (P<0.001) and were significantly lower in men with diabetes, hypertension, hyperlipidemia, and known CVD, but were higher in current smokers compared with nonsmokers (P<0.001). Hormone levels were highest in August-October declined after and lowest in March. Overall, both total and bioavailable testosterone levels were significantly lower in March compared to August-October (P<0.001). In a linear regression analysis, age, BMI, current smoking, and month of testing were independently associated with total (P<0.001) and bioavailable testosterone levels (P=0.002), and diabetes was associated with total testosterone (P<0.001). Conclusion. In a large cohort of men with a wide range of age, BMI, and comorbidities, month of testing was independently associated with total and bioavailable testosterone levels. These data provide strong evidence that seasonal variation has to be considered in clinical practice.

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Current nanomaterial research is focused on the medical applications of nanotechnology, whereas side effects associated with nanotechnology use, especially the environmental impacts, are not taken into consideration during the engineering process. Nanomedical users and developers are faced with the challenge of balancing the medical and societal benefits and risks associated with nanotechnology. The adequacy of available tools, such as physiologically-based pharmacokinetic modeling or predictive structure-activity relationships, in assessing the toxicity and risk associated with specific nanomaterials is unknown. Successful development of future nanomedical devices and pharmaceuticals thus requires a consolidated information base to select the optimal nanomaterial in a given situation--understanding the toxicology and potential side effects associated with candidate materials for medical applications, understanding product life cycle, and communicating effectively with personnel, stakeholders, and regulators. This can be achieved through an innovative combination of toxicology, risk assessment modeling, and tools developed in the field of multicriteria decision analysis (MCDA).

Ultraviolet (UV) light affects endocrinological and behavioral aspects of sexuality via an unknown mechanism. Here we discover that ultraviolet B (UVB) exposure enhances the levels of sex-steroid hormones and sexual behavior, which are mediated by the skin. In female mice, UVB exposure increases hypothalamus-pituitary-gonadal axis hormone levels, resulting in larger ovaries; extends estrus days; and increases anti-Mullerian hormone (AMH) expression. UVB exposure also enhances the sexual responsiveness and attractiveness of females and male-female interactions. Conditional knockout of p53 specifically in skin keratinocytes abolishes the effects of UVB. Thus, UVB triggers a skin-brain-gonadal axis through skin p53 activation. In humans, solar exposure enhances romantic passion in both genders and aggressiveness in men, as seen in analysis of individual questionaries, and positively correlates with testosterone level. Our findings suggest opportunities for treatment of sex-steroid-related dysfunctions.

BACKGROUND:Acute otitis media (AOM) is a common cause for antibiotic prescription. Most guidelines endorse abstaining from immediate antibiotic treatment ('watchful waiting', WW) in mild-moderate episodes. We studied adherence rates to the latest AOM guidelines (2013), in terms of antibiotic type and prescription options.METHODS:In this population-based study, AOM episodes were identified in Clalit Health Services-insured children aged 0-10 years between 2011 and 2018, using a data-sharing platform. After identifying the index, prescription and issuing dates for antibiotics for each AOM episode, treatment was categorized as immediate (≤2 days after diagnosis) or WW (antibiotic not prescribed/issued; prescribed ≤2 days after diagnosis but issued on Days 2-7; or prescribed/issued on Days 2-7). Guideline adherence was measured according to age.RESULTS:Of the 491 106 episodes, 361 518 (73.6%) were treated with antibiotics. Following the 2013 guidelines, the ratio of episodes in children aged ≤6 months that were adherent (immediate treatment) was higher (OR = 1.22; 95% CI 1.15-1.29; P < 0.001), whereas the adherent episode ratio for children aged 6-24 months and 2-10 years (WW) was lower (OR = 0.87; 95% CI 0.85-0.88 and OR = 0.94; 95% CI 0.92-0.96, respectively; P < 0.001). Antibiotic prescription rates after 2013 for children aged ≤6 months were not different (OR = 1.03; 95% CI 0.96-1.1; P = 0.4), but were higher in children aged 6-24 months and 2-10 years (OR = 1.07; 95% CI 1.05-1.09; P < 0.001 and OR = 1.02; 95% CI 1.01-1.04; P = 0.015, respectively). Amoxicillin was the most common antibiotic, administered in 75.6% of episodes. Azithromycin was most commonly associated with treatment failure (6.6%).CONCLUSIONS:Improved adherence to the 2013 guidelines was observed only in children aged ≤6 months and over-treatment with antibiotics was still high.