[Association analysis between mixed exposure to phenols and semen quality].

Phenols such as bisphenols, parabens, and triclosan are common environmental endocrine disruptors. Previous epidemiological studies have suggested that phenols may affect semen quality, but the results were inconsistent. In addition, most existing studies have been limited to the effects of a single chemical compound, ignoring the health effects of mixed exposure to multiple chemicals. Thus, we aimed to explore the associations between individual and mixed exposure to phenols and various semen quality parameters. In this study, a rapid and sensitive method was used to determine 18 phenolic compounds in urine samples of 799 volunteers who donated sperm samples to the Shanghai Human Sperm Bank. A spot urine sample was collected from each subject on the day of their clinic visit and stored at -20 ℃ until testing. Urine samples (200 µL) were extracted and added with 20 µL of an internal standard and 50 µL of ß-glucuronidase solution. The mixtures were then incubated for 12 h at 37 ℃. After hydrolysis, the samples were extracted twice using ethyl acetate (500 µL). The concentrations of the 18 phenolic compounds were measured using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Semen quality parameters were analyzed using a computer-aided semen analyzer. Multiple linear regressions were used to detect the associations between individual phenol exposure and semen quality parameters. In addition, weighted quantile sum (WQS) models were used to explore the associations between mixed-phenol exposure and semen quality parameters. After adjusting for potential covariates, the results of multiple linear regressions showed that exposure to ethyl paraben (EtP) was significantly negatively associated with sperm concentration and total sperm count (P<0.05). In addition, exposure to mixed phenols was significantly associated with decreased sperm concentration; methyl paraben (MeP) and EtP were identified as the main contributors to this decrease. Thus, phenol exposure may be associated with decreased semen quality in young males, particularly with respect to sperm concentration and total sperm count.

Clinical Significance of the Sympathetic Nervous System in the Development and Progression of Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is defined as a complex disease of clinically characterized by elevated pulmonary pressure eventually resulting in right heart failure and premature death. To date, PAH still remains a life-threatening disease. Published evidence suggests that patients with PAH present profound sympathetic nervous system abnormalities and sympathetic activity has been shown to be increased. The mechanism of PAH is still complex and poorly understood. RESULTS: Some data have showed that adrenoceptors are involved in the process of the pathology and have different functions in the progression of PAH followed by heart failure. Alpha-adrenergic receptors mediate most excitatory effects and induce growth of smooth muscle cells and adventitial fibroblasts via complex cellular and molecular mechanisms. However, beta-adrenergic receptor mainly detected in endothelial layer commonly exerts relaxation effects on pulmonary artery. In addition, G protein-coupled receptor kinase 2, the primary G protein-coupled receptor kinase expressed in the heart, has been shown to be increased, resulting in the distinctive loss of inotropic reserve and functional capacity of the failing heart according to the activation of sympathetic nervous system. CONCLUSION: Here, we summarize the relevant available studies describing the roles of sympathetic nervous system in the progression of PAH.

[Relationship of the intensity of Schistosoma japonicum infection to the variation in individual egg count].

OBJECTIVE: To investigate the relationship of the intensity of Schistosoma japonicum infection with the variation in individual egg counts. METHODS: Stool specimens were collected from residents in a village in Jiangxi Province and examined with Kato-Katz thick smear method for seven consecutive days. Two smears were prepared and microscopically examined for each specimen. 570 individuals completed the investigation. Coefficient of variation (CV) was used to assess the intra-individual variation of the egg counts, in relation to the demographic characteristics including age, sex, occupation, and the intensity of infection. RESULTS: The proportion of individuals with at least one positive finding increased from 33.0% in a single measurement to 56.5% by seven measurements (P<0.01). The average intensity of infection in a single Kato-Katz test (111.06 EPG) was markedly higher than the average accumulated intensity of infection (42.51 EPG). Variation of intra-individual: the variation of CV in female infected subjects was higher than males (P<0.05). The variation of CV in 0-9 age group was higher than other age groups (P<0.05). The lowest variation of CV was detected in fishermen (P<0.05), but no statistical difference was found among other occupation groups. With an increase of the intensity of infection, the variation of CV decreased gradually. A negative correlation was observed between the variation of CV and the intensity of infection(r=-0.717, P<0.01). There was no significant difference in variation of CV between males and females, age and occupation groups when data were stratified according to the intensity of infection (P>0.05). CONCLUSION: The prevalence and intensity of S. japonicum infection by single Kato-Katz test was obviously lower than the real figures. The intensity of infection may be an essential factor that affects the intra-individual variation of egg counts.