Chlorpyrifos alters expression of enzymes involved in vitamin D3 synthesis in skin cells.

Skin acts as a mechanical barrier between human body and environment. Epidermal cells are regularly exposed to many physiological and environmental stressors, such as pesticides, like chlorpyrifos (CPS). It is recognised that CPS may affect metabolism of other exo- and endogenous substances by affecting enzyme activity and expression. This study aims to investigate the effect of CPS on expression of CYP27A1, CYP27B1 and CYP24A1, the enzymes involved in synthesis and metabolism of vitamin D3, in human keratinocytes HaCaT and human fibroblasts BJ. Synthesis of vitamin D3 in cells was initiated by irradiating with UVB. Expression of CYP27A1, CYP27B1 and CYP24A1 was evaluated by RT-qPCR and Western blot. Our experiments revealed that expression of all tested cytochrome P450 isoforms in cells exposed to CPS changed significantly. Exposure of HaCaT keratinocytes to CPS decreased CYP27A1 mRNA levels, but increased CYP27B1 and CYP24A1 mRNA levels. This was confirmed at the protein level, except for the CYP27A1 expression. Outcome for the BJ cells was however less conclusive. Though exposure to CPS decreased CYP27A1 and CYP27B1 mRNA levels, at protein level increasing concentration of CPS and UVB intensity induced expression of CYP27A1 and CYP24A1. The expression of CYP27B1 isoform decreased in line with mRNA level. Nevertheless, it can be concluded that CPS may therefore interrupt vitamin D3 metabolism in skin cells, but further studies are required to better understand such mechanisms.

Prevalence and selected determinants of the risk of problem gambling among Polish secondary school students.

OBJECTIVE: The study had two aims. The first was to determine the prevalence of various types of gambling behaviour and the severity of gambling among secondary school students in one of the poorest provinces in Poland. The second was to identify correlations between selected socio-demographic variables and the severity of gambling problems. MATERIAL AND METHODS: The study was carried out on a group of teenagers from secondary schools in the Lublin Province of eastern Poland. The survey covered 923 respondents aged 17 - 21 (M=18.06; SD=0.367). The study used a list of gambling activities, the South Oaks Gambling Screen-Revised Adolescent (SOGS-RA), and a socio-demographic questionnaire. The effects of independent variables on the severity of gambling behaviour were evaluated using the Mann-Whitney U test (for binary variables, such as gender or age group) and Kruskal-Wallis one-way ANOVA for ternary variables (e.g., place of residence, type of school). RESULTS AND CONCLUSIONS: The findings show that in the studied population 7.2% were pathological gamblers and 41.8% had not gambled during the 12 months prior to the study. These findings are consistent with the literature. There seems to be a clear trend in which pathological gambling is found most frequently among technical secondary school students, and least frequently among those from secondary schools of general education. In addition, persons who had lived (until the age of 10) in rural areas scored the lowest in SOGS-RA, while those from cities below 50,000 residents, scored the highest. In families with a gambling member, pathological gambling was found 1.7 times more frequently.