BackgroundAlthough HIV and syphilis co-infection has been frequently observed in men who have sex with men (MSM), only few studies have focused on it. Different subgroups of MSM might exhibit heterogeneous HIV and syphilis risk profiles, indicating that interventions for HIV and HIV-related co-infections may vary with different subgroups of MSM. However, no previous study has investigated HIV and syphilis co-infection among non-commercial MSM (ncMSM) attending a sexually transmitted disease (STD) clinic. Therefore, this study aimed to explore the prevalence of HIV and syphilis co-infection and associated factors among ncMSM attending an STD clinic in Shenzhen, China.MethodsNcMSM attending the STD clinic of Shenzhen Center for Chronic Disease Control were recruited in this cross-sectional study every Monday between March 2013 and August 2015 using a site based convenience sampling method. An anonymous questionnaire was used to collect data regarding socio-demographic characteristics, risky sexual behaviors and HIV-related knowledge. Blood samples were collected to perform HIV and syphilis tests.ResultsTotally 533 participants were enrolled in this study and the prevalence of HIV and syphilis co-infection among them was 13.13%. Multivariable analyses indicated that having lived in Shenzhen for less than one year (aOR = 2.80, 95% CI = 1.30–6.05), having first anal sexual intercourse before the age of 18 (aOR = 2.78, 95% CI = 1.29–5.89), having 3 to 5 anal sexual partners in the past six months (aOR = 2.54, 95% CI = 1.19–5.40), playing exclusively receptive (aOR = 6.87, 95% CI = 3.02–15.61) or both insertive and receptive (aOR = 3.65, 95% CI = 1.64–8.09) roles in anal sexual intercourse and not always using condom in anal sexual intercourse (aOR = 2.13, 95% CI = 1.08–4.19) were associated risk factors for HIV and syphilis co-infection, relative to the non-infected ncMSM. Compared with the mono-infected ncMSM, associated risk factors for the co-infection were being unmarried (aOR = 2.47, 95% CI = 1.03–5.89) and playing exclusively receptive role (aOR = 2.44, 95% CI = 1.04–5.73) in anal sexual intercourse.ConclusionsHIV and syphilis co-infection is quite prevalent among the study participants in Shenzhen. Integrated and intensified intervention strategies, specifically targeting at the non-infected and mono-infected ncMSM attending the STD clinic, are needed to reduce HIV and syphilis co-infection. Most importantly, non-infected and mono-infected ncMSM attending the STD clinic with the aforementioned associated risk factors should be given special concern.

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Studies investigating the association between early sexual debut and human immunodeficiency virus (HIV) infection have mainly focused on Africans or females but rarely on men who have sex with men (MSM) in China. This study, therefore, mainly aimed at exploring the association between early sexual debut and HIV infection among MSM in Shenzhen, China. A total of 533 MSM were enrolled in this study using a convenience sampling method. Information about sociodemographic characteristics and risky sexual behaviors was collected. It was found that the prevalence of HIV infection was 24.2% among this study population and 66.4% of the MSM reported having had vaginal sexual intercourse with females. The mean ages at first vaginal sexual intercourse, first anal sexual intercourse, and first sexual intercourse were 21.38, 22.43, and 19.87 years, respectively. Multivariable logistic regression analyses showed that the MSM who experienced early anal sexual debut were more likely to be infected with HIV than those who did not. The results indicate that HIV infection is quite prevalent among MSM in Shenzhen. Early and efficient intervention strategies should be taken, and the MSM experiencing early anal sexual debut should be given special attention.

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Ambient temperature-associated stress can affect normal physiological functions in ectotherms. To assess the effects of cold or heat stress on amphibians, giant spiny frogs () were acclimated at 22°C followed by exposure to 5°C or 30°C for 0, 3, 6, 12, 24 and 48 h, respectively. Histological alterations, apoptotic index, generation of mitochondrial reactive oxygen species (ROS), antioxidant activity indices and stress-response gene expression in frog livers were subsequently determined. Results showed that many fat droplets appeared after 12 h of heat stress and the percentage of melanomacrophage centres significantly changed after 48 h at both stress conditions. Furthermore, the mitochondrial ROS levels were elevated in a time-dependent manner up to 6 h and 12 h in the cold and heat stress groups, respectively. The activities of superoxide dismutase, glutathione peroxidase and catalase were successively increased with increasing periods of cold or heat exposure, and their gene expression levels showed similar changes in both stress conditions. Most tested heat shock protein (HSP) genes were sensitive to temperature exposure, and the expression profiles of most apoptosis-related genes was significantly upregulated at 3 and 48 h under cold and heat stress, respectively. Apoptotic index at 48 h under cold stress was significantly higher than that under heat stress. Notably, lipid droplets, , and might be suitable bioindicators of heat stress. The results of these alterations at physiological, biochemical and molecular levels might contribute to a better understanding of the stress response of, and perhaps amphibians more generally, under thermal stress.