Preliminary validation of the self-report measure assessing experiences of negative independent and dependent event frequency in Japanese university students.

Background: In the past, different stress generation studies have used self-report measures comprising different items to assess each category of negative events. Moreover, the validity of these scales has not been adequately investigated. Therefore, we developed a self-report measure dedicated to assessing experiences of negative interpersonal dependent events, negative non-interpersonal dependent events, and negative independent events in university students, which was named the Negative Independent/Dependent Events Scale. Methods: Japanese undergraduate students (N = 247; mean age = 19.18 years, SD = 3.08) responded to the Negative Independent/Dependent Events Scale, which had items selected for adequate content validity. They also responded to self-report measures of depressive symptoms, reassurance-seeking behaviors, inattention, and lack of perseverance. Results: All the negative events subscales had moderate positive correlations with depressive symptoms. In addition, the negative interpersonal dependent events subscale showed a moderate positive correlation with reassurance-seeking behaviors, and the negative non-interpersonal dependent events subscale showed a strong positive correlation with inattention. Furthermore, the negative non-interpersonal dependent events subscale was more strongly correlated with inattention than the other two negative events subscales. In contrast, the negative interpersonal dependent events subscale was more strongly correlated with reassurance-seeking behaviors than with the negative independent events subscale but not more strongly than with the negative non-interpersonal dependent events subscale. Conclusions: These findings indicated the acceptable construct validity of the Negative Independent/Dependent Events Scale. However, further research is necessary to establish the discriminant validity of the negative interpersonal dependent events subscale and the negative non-interpersonal dependent events subscale.

Causes and consequences of stress generation: Longitudinal associations of negative events, aggressive behaviors, rumination, and depressive symptoms.

The present study examined the causes and consequences of stress generation in university students in Japan. A two-wave longitudinal study with an 8- or 9-week interval was conducted in the fall of 2020. Undergraduate and graduate students at four universities in Japan (N = 201) completed self-report measures assessing experiences of negative interpersonal dependent events, negative non-interpersonal events, and negative independent events at two times. At the same time, they also responded to measures of aggressive behaviors, trait rumination, and depressive symptoms. Path analyses revealed that baseline aggressive behaviors were positively associated with an increase in subsequent negative interpersonal dependent events, even after controlling for the influences of negative interpersonal dependent events, rumination, and depressive symptoms at baseline. However, aggressive behaviors were not significantly associated with subsequent negative non-interpersonal dependent events or negative independent events. These findings suggest that aggressive behaviors may have been a factor leading to interpersonal stress generation. Furthermore, all categories of negative event experiences predicted an increase in subsequent depressive symptoms, but not subsequent rumination, and rumination was not significantly associated with subsequent depressive symptoms. This research extends previous studies on the causes and consequences of stress generation conducted in the US by using specific measures of aggressive behaviors and including a non-restricted sample of university students in Japan. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12144-022-02859-9.

Sake lees extract improves hepatic lipid accumulation in high fat diet-fed mice.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is increasing worldwide as one of the leading causes of chronic liver disease. Sake lees (SL) are secondary products of sake manufacturing and are considered to have beneficial effects on human health. To investigate these effects, we used high fat diet (HFD)-fed mice treated with or without the SL extract. METHOD: Mice were the HFD ad libitum for 8 weeks and were administered 500 µL of distilled water with or without the SL extract (350 mg/mL) by a feeding needle daily for the last 4 weeks. Food intake, body weight, and liver weight were measured. Triacylglycerol content and the mRNA and protein expression levels of various lipid and glucose metabolism-related genes were determined in liver tissues. The levels of triglyceride, free fatty acids, glucose, insulin, and liver cell damage markers were determined in serum. Fatty acid-induced lipid accumulation in HepG2 cells was assessed in the presence or absence of the SL extract. RESULTS: Mice fed a HFD and treated with the SL extract demonstrated a significant reduction in hepatic lipid accumulation and mRNA and protein levels of peroxidome proliferator-activated receptor γ (PPARγ), PPARα, CD36, and phosphoenolpyruvate carboxykinase 1 in the liver, while the SL extract did not affect body weight and food intake. Moreover, insulin resistance and hepatic inflammation in HFD-fed mice improved after administration of the SL extract. In HepG2 cells, the SL extract suppressed fatty acid-induced intracellular lipid accumulation. CONCLUSIONS: These findings suggest that treatment with the SL extract could potentially reduce the risk of NAFLD development, and that the SL extract may be clinically useful for the treatment of NAFLD.