Biomedical subjects

Masayo Kojima

Publications and source records attributed to Masayo Kojima.

25 records · Page 2Linked to original sources

PubMed2003

Smoking and colorectal cancer in a non-Western population: a prospective cohort study in Japan.

BACKGROUND: The risk of colorectal cancer in relation to smoking habits has been examined mostly in Caucasians, and evidence for other ethnic groups is still scarce. METHODS: Our data came from the Japan Collaborative Cohort (JACC) Study. From 1988 through 1990, 25,260 men and 34,619 women aged 40-79 years completed a questionnaire on cigarette smoking and other lifestyle factors. Hazard ratios (HR) were estimated by fitting proportional hazards models. RESULTS: During the mean follow-up of 7.6 years through December 1997, we documented 408 incident colon cancers and 204 rectal cancers. We found a non-significant increase in colon cancer risk in male current smokers compared with never smokers. The multivariate-adjusted hazard ratios were 1.07 (95% confidence interval [CI]: 0.72-1.59) for ex-smokers and 1.23 (95% CI: 0.85-1.78) for current smokers. We however failed to observe a clear dose-response relationship between smoking intensity or duration and colon cancer risk. The adjusted hazard ratio was 1.07 (95% CI: 0.71-1.61) even for 40+ years of smoking. Almost no increase in colon cancer risk was detected for female smokers, and male smokers were not at an enhanced risk of rectal cancer. CONCLUSIONS: Cigarette smoking was not a strong risk factor for colorectal cancer even after a long-term exposure, although a weak association remains open to discussion.

Adult↗

PubMed2002

Cross-cultural validation of the Beck Depression Inventory-II in Japan.

The Beck Depression Inventory has undergone substantial revision recently as the BDI-II to correspond to DSM-IV criteria. We developed the Japanese version of the BDI-II and examined its psychometric properties. The linguistic equivalence was verified by a back-translation method. The final translation was administered to the visitors at a public health care center, and the responses of 766 adults (age = 24-82 years, women = 40%) were analyzed. Half of the participants completed the Center for Epidemiologic Studies Depression Scale (CES-D) as well. A high level of internal consistency reliability (Cronbach's alpha = 0.87) and item homogeneity was confirmed. Exploratory factor analysis showed a two-factor structure (cognitive and somatic-affective), which was almost identical to the original model demonstrated by Beck et al. (1996, Manual for the Beck Depression Inventor Psychological Corporation, San Antonio, TX, USA). The following confirmatory factor analysis also supported the two-factor structure. Adequate correlation (r = 0.69, P < 0.001) between the total score of the BDI-II and that of the CES-D was observed. A higher score for women compared to men, without significant age differences, was consistent with the results of previous reports. We conclude that the Japanese version of the BDI-II is psychometrically robust and can be used to assess depressive symptoms in Japanese people.

Adult↗

PubMed2002

Proteasome-driven turnover of tryptophan hydroxylase is triggered by phosphorylation in RBL2H3 cells, a serotonin producing mast cell line.

We previously demonstrated in mast cell lines RBL2H3 and FMA3 that tryptophan hydroxylase (TPH) undergoes very fast turnover driven by 26S-proteasomes [Kojima, M., Oguro, K., Sawabe, K., Iida, Y., Ikeda, R., Yamashita, A., Nakanishi, N. & Hasegawa, H. (2000) J. Biochem (Tokyo) 2000, 127, 121-127]. In the present study, we have examined an involvement of TPH phosphorylation in the rapid turnover, using non-neural TPH. The proteasome-driven degradation of TPH in living cells was accelerated by okadaic acid, a protein phosphatase inhibitor. Incorporation of 32P into a 53-kDa protein, which was judged to be TPH based on autoradiography and Western blot analysis using anti-TPH serum and purified TPH as the size marker, was observed in FMA3 cells only in the presence of both okadaic acid and MG132, inhibitors of protein phosphatase and proteasome, respectively. In a cell-free proteasome system constituted mainly of RBL2H3 cell extracts, degradation of exogenous TPH isolated from mastocytoma P-815 cells was inhibited by protein kinase inhibitors KN-62 and K252a but not by H89. Consistent with the inhibitor specificity, the same TPH was phosphorylated by exogenous Ca2+/calmodulin-dependent protein kinase II in the presence of Ca2+ and calmodulin but not by protein kinase A (catalytic subunit). TPH protein thus phosphorylated by Ca2+/calmodulin-dependent protein kinase II was digested more rapidly in the cell-free proteasome system than was the nonphosphorylated enzyme. These results indicated that the phosphorylation of TPH was a prerequisite for proteasome-driven TPH degradation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed2002

[An example of psychometric validation of a mental health questionnaire used at a work place].

Most companies utilize original questionnaires developed by the health-care staff to evaluate their workers' mental health status. To build effective strategies, it is crucial to use proper measures validated psychometrically. We demonstrated the process to evaluate the reliability and validity of the original health questionnaire developed by the health-care team of an industrial company. We used the Beck Depression Inventory-II, and the Job Content Questionnaire as the gold standards for external validation. Out of 21 items in the original health questionnaire, 9 items significantly correlated with depression. From the results of a factor analysis, the 9 items composed 2 independent components out of 5 factors. A subscale which consisted of the 9 items from the original questionnaire was proposed as a screening tool to detect depression, but no items of the original questionnaire correlate with the Support subscale nor the Job Control subscales of the JCQ. Just one item correlated with the Job Demand subscale of the JCQ. Additional information should be added to the original questionnaire to evaluate Job Stress based on the Karsek's Job Demand-Control-Support model.

Humans↗

PubMedDate not supplied

Perceived psychologic stress and colorectal cancer mortality: findings from the Japan Collaborative Cohort Study.

OBJECTIVE: The purpose of this research was to examine the relationship between perceived psychologic stress and colorectal cancer mortality in a prospective large-scale study. METHODS: Between the years 1988 and 1990, 32,153 men and 45,854 women aged 40 to 79 years were enrolled. Participants completed a self-administered questionnaire that addressed demographic, lifestyle, and psychosocial characteristics. Subjects were subsequently followed for mortality until the end of 1999. Perceived psychologic stress was assessed using the question "Do you feel stress during your daily life?" The 4 possible responses, ranging from "little or none" (1) to "extreme" (4), were dichotomized as low (1 or 2) or high (3 or 4) stress. Relative risks (RRs) with 95% confidence intervals (CIs) for colon and rectal cancer according to the perceived level of stress were estimated using Cox's proportional hazard model. RESULTS: During the follow-up period (average, 9.6 years), 193 colon cancer deaths (96 men and 97 women) and 127 rectal cancer deaths (88 men and 39 women) were confirmed within the study group. Women who reported high stress had a 1.64-fold higher risk of colon cancer mortality (multivariate-adjusted RR, 1.64; 95% CI, 1.01-2.66) compared with those reporting low stress. There was no significant association between perceived stress and female rectal cancer or male colon and rectal cancer mortality. CONCLUSIONS: Perceived psychologic stress was weakly associated with increased mortality from colon cancer in women. No positive or inverse association was found in men. Further studies are needed to confirm our results.

Adult↗

PubMedDate not supplied

Alexithymia, depression and social support among Japanese workers.

BACKGROUND: A number of studies have shown that social support has a direct beneficial effect on well-being and also serves as a buffer to protect people from health problems due to excessive stress. Although preliminary studies report a positive relationship of alexithymia both with depression and reduced social support, there is no study examining whether the beneficial effect of social support on depression differs with the presence of alexithymia. METHODS: A total of 120 workers aged 19-39 completed the 20-item Toronto Alexithymia Scale (TAS-20) to measure alexithymia, the Beck Depression Inventory-II (BDI-II) to evaluate depressive symptomatology, and the Job Content Questionnaire (JCQ) to assess job strain based on Karasek's demand-control-support model. The interrelationship among TAS-20, BDI-II and 3 subscales of JCQ (job demand, control, and support) were examined. RESULTS: A significant association of depression with low support and high alexithymia was observed. Alexithymia was also associated with reduced support. Further, a statistically significant interaction between alexithymia and support in terms of their effect on depression was observed. Nonalexithymic individuals with low support showed a significantly higher depression score than those who received high support, while alexithymics did not differ in their depression score depending on the degree of support. Consistent results were obtained from the logistic regression analysis examining the odds ratio for depression by support by alexithymia; a significantly increased odds ratio for depression associated with low social support was observed only among nonalexithymics. CONCLUSIONS: Alexithymic individuals might be unable to benefit from social support because of their cognitive deficits of emotion.

Adult↗

PubMedDate not supplied

Relationship between obesity and serum markers of oxidative stress and inflammation in Japanese.

The present study was conducted to assess the relationship between obesity and serum levels of C-reactive protein (CRP), carotenoids, oxidized LDL (oxLDL), oxidized LDL antibodies (oLAB), and leptin in Japanese residents. The subjects were 158 males and 158 females aged 40-79 years, and living in Hokkaido, Japan, who attended a health examination screening. Serum levels of CRP, oxLDL, oLAB, and leptin were measured by enzyme-linked immunosorbent assay (ELISA) and serum carotenoid levels were measured by high-performance liquid chromatography (HPLC). Body mass index (BMI) was calculated as body weight (kg) divided by height (m) squared and obesity was defined as BMI of 25 or more (kg/m2). Serum levels of CRP and leptin were significantly higher in the obese group than in their non-obese counterparts in both genders. Serum levels of beta-carotene and beta-cryptoxanthin were lower in the obese individuals, especially in females. While values for oxLDL and oLAB did not significantly vary. BMI was positively correlated with log-transformed serum levels of CRP and leptin in both genders (males: r=0.231, p<0.05; females: r=0.305, p<0.001). In females, moreover, BMI was negatively correlated with log-transformed serum levels of beta-carotene, zeaxanthin/lutein, and beta-cryptoxanthin (r=-0.244, p<0.01; r=-0.200, p<0.05; r=-0.207, p<0.01, respectively). Significantly higher odds ratios (ORs) for high serum levels of CRP (males: OR=2.12; females: OR=3.96) and leptin (males: OR=3.83; females: OR=9.07) were observed in obese versus non-obese men and women, after adjusting for various confounding factors. Significantly lower adjusted odds ratios for high serum levels of alpha- and beta-carotenes (males: OR=0.23, 0.33; females: OR=0.35, 0.39, respectively) were also observed in the obese as compared to the non-obese group. In conclusion, obesity is highly associated with states of oxidative stress and low-grade inflammation in Japanese residents, suggesting that these latter might play an important role in the association between a high BMI and certain cancers as well as coronary heart disease (CHD).

Adult↗