We have synthesized new polycationic bactericides, poly[oxyethylene(dimethyliminio)trimethylene(dimethyliminio)ethylene dichloride] (OXD) and poly(hexamethyleneguanidine phosphate) (HEP), in order to develop more active but less skin-irritative bactericides. The effects of these bactericides on Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, methicillin resistant Staphylococcus aureus (MRSA) and the degree of their irritations on skin were compared with those of a widely used low molecular-weight cationic bactericide, benzalkonium chloride (BAC), and a polycationic bactericide, poly[2-hydroxyethylene(dimethyliminio)methylene chloride] (2HYC). The minimum bactericidal concentration (MBC) of OXD for 10 min contact incubation was 16 μg/ml against P. aeruginosa, E. coli, S. marcescens and K. pneumoniae, and >1000 μg/ml against MRSA. The MBC of HEP for 10 min contact incubation was 16 μg/ml against P. aeruginosa, 32 μg/ml against E. coli and K. pneumoniae, and 64 μg/ml against S. marcescens and MRSA. Itch, edema, erythema, heat, injury, desquamation and keratinization caused by skin irritation were examined in 21 subjects by patch tests. Only one subject treated with OXD experienced edema, and one subject with HEP experienced keratinization. However, BAC caused itch in 3 subjects, edema in 1, erythema in 10 and desquamation in 2, indicating that the incidence of skin irritation of BAC was higher than that of OXD or HEP. OXD and HEP had sterilization ability similar to BAC, however, they were less skin-irritative than BAC. This indicates that OXD and HEP can be used as safe bactericides.

Objectives Students’ depressive symptoms might be related to their own risk factors and to their parents’ status. The objective of this cross-sectional study was to examine the relationship of depressive symptoms with lifestyle variables and parents’ psychological and socio-demographic status among Japanese junior high school students. Methods Of 477 students and their parents, 409 (85.7 %) students and 314 (65.8 %) parents participated in the study. Students answered self-reported questionnaire on depressive symptoms, their heights and weights, subjective stress, body dissatisfaction, lifestyles including sleep duration and extracurricular physical activity in school and other physical activity outside the school, and nutritional intake. Parents responded to questionnaire on depressive symptoms and socio-demographic status. Results The prevalence of depressive symptoms was 24.9 %. Students with depressive symptoms were more likely to have stress. Students in shorter and longer sleep duration groups were more likely to have depressive symptoms. The students with depressive symptoms had smaller amount of energy intake than did those without depressive symptoms. Multiple logistic regression analysis revealed significant relationships between students’ depressive symptoms and some independent variables. Sex, subjective stress, “almost-never”-categorized extracurricular physical activity in school and other physical activity outside the school, and having a parent with depressive symptoms were significantly associated with students’ depressive symptoms. Conclusion Reducing mental stress and taking care of lifestyles, especially, “almost-everyday”-categorized extracurricular physical activity in school and other physical activity outside the school, may have benefits for students’ mental health, and having a parent with depressive symptoms may be associated with students’ depressive symptoms.

To evaluate the effects of bovine lactoferrin (LF)-containing yogurt on gastroenteritis in nursery school children during the winter season, we conducted a randomized prospective study. A total of 1296 children were randomized into a group in which LF was provided in yogurt (LF group, n = 661) and a non-LF consumption group (control group, n = 635). The LF group was given LF-containing yogurt (100 mg/day) on all 5 weekdays for approximately 15 weeks, and the control group consumed fruit jelly instead of the yogurt. The final totals of 578 children as the LF group and 584 as the control group were analyzed. The total number of children who were absent from school due to vomiting was significantly lower in the LF group compared to the control, accounting for ≥3 days in any week: 10/234 (4.3%) vs. 49/584 (8.4%), respectively; p = 0.04. Regarding the relationship between absences due to vomiting and the consumption of the LF-containing yogurt, the adjusted odds ratio for absence due to vomiting was 2.48 (95% CI: 1.19–5.14) in the LF children who consumed LF-containing yogurt ≤2 days/week compared to the LF children who consumed the yogurt ≥ 3 days/week. The consumption of LF-containing yogurt (100 mg/day) for ≥3 days/week might help alleviate the symptom of vomiting in nursery school children during the winter.