Comparison of ET-1 and eNOS expressions in yak testes at different developmental stages.

Yak has strong adaptability to plateau hypoxia environment. However, the endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) are important regulators in blood oxygen transportation. Yak testes: newborn (3 days), young (1 years), adult (4 years) and old (9 years) were collected for microscopic analyses using haematoxylin and eosin staining (H&E), immunohistochemistry and immunofluorescence, as well as Western blot to compare the expression of ET-1 and eNOS. Furthermore, the levels of ET-1 mRNA and eNOS mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR). The results showed that ET-1 mRNA and eNOS mRNA in old yaks were higher than other developmental stages (p < .01). And the levels of ET-1 and eNOS protein increased with age. Immunohistochemistry and immunofluorescence showed that ET-1 and eNOS were mainly localized in gonocytes and spermatogenic membrane of newborn yaks. These two factors were expressed in both Leydig cells of young yaks and endothelial cells of adult yaks. In old yaks, ET-1 was mainly expressed in Sertoli cells, while eNOS was obviously positive in capillaries and Leydig cells. Therefore, the positive results of ET-1 and eNOS in gonocyte and spermatogenic basement were closely related to the development of testes. The expression of Leydig and Sertoli cells indicated that they played an important role in testes function. The expression in endothelial cells or interstitial capillaries, suggesting that they are involved in the regulation of microcirculation in yak testes. This study could provide clues for further revealing the regulation of yak testicular blood vessels in alpine cold and hypoxic environments.

Self-perceived burden predicts lower quality of life in advanced cancer patients: the mediating role of existential distress and anxiety.

BACKGROUND: Self-perceived burden (SPB) is an important predictor of quality of life (QoL) in patients with advanced cancer. However, the mechanism how SPB affects patients' QoL remains unclear. This study aimed to examine the potential mediating roles of existential distress (ED) and anxiety in the relationship between SPB and QoL. METHODS: A multicenter cross-sectional study was conducted. 352 advanced cancer patients were recruited from three hospitals in southeast of China. The Self-perceived Burden Scale, the Existential Distress Scale, the Hospital Anxiety and Depression Scale, and the Quality-of-Life Concerns in the End of Life Questionnaire were adopted to collect data. Hayes's bootstrapping method was used to analyze the data. RESULTS: SPB was negatively associated with QoL (P < 0.01). ED and anxiety partially mediated the relationship between SPB and QoL (P < 0.01). Moreover, ED had direct effects on anxiety, and sequentially QoL (P < 0.01). The serial multiple mediation model of SPB accounted for 73.25% of the variance in QoL in advanced cancer patients. CONCLUSIONS: ED and anxiety are important mediating factors between SPB and QoL in advanced cancer patients. To improve patients' QoL, comprehensive interventions for reducing anxiety and ED are highly recommended in clinical practices.