Effect of dietary mineral sources and oil content on calcium utilization and kidney calcification in female Fischer rats fed low-protein diets.

We studied the effects of dietary mineral source and oil intake on kidney calcification in 4-wk-old female Fischer rats after consuming the AIN-76 purified diet (AIN-76). A modified AIN-76 mineral mixture was used, although the original calcium (Ca)/phosphorus (P) molar ratio remained unchanged. Rats were fed the modified diets for a period of 40 d before their kidneys were removed on the last day. Ca balance tests were performed on days 31 to 36 and biochemical analysis of urine was also studied. Kidney Ca, P, and magnesium (Mg) in the standard diet group (20% protein and 5% oil) were not affected by the mineral source. Kidney Ca, P, and Mg in the low-protein (10% protein) diet group, were found to be influenced by the dietary oil content and mineral source. In particular, the different mineral sources differentially increased kidney mineral accumulation. Pathological examination of the kidney showed that the degree of kidney calcification was proportional to the dietary oil content in the 10% dietary protein group, reflecting the calcium content of the kidney. The information gathered on mineral sources in this study will help future researchers studying the influence of dietary Ca/P molar ratios, and histological changes in the kidney.

Relationship between RBC mercury levels and serum n3 polyunsaturated fatty acid concentrations among Japanese men and women.

AIMS: To evaluate potential health risk and benefits of fish consumption, the association of fish consumption with total mercury levels in red blood cells (RBCs) and serum eicosapentaenoic acid (EPA) concentrations was examined. SUBJECTS AND METHODS: Study subjects were 269 Japanese (98 men and 171 women) living in a remote island of Kagoshima, and their blood was drawn in 1994. RESULTS: Total mercury levels were related to weekly fish consumption among women (P = 0.035) but not among men (P = 0.643). However, serum EPA levels were not related to fish consumption in both women and men. In contrast, EPA levels in the high-density ipoprotein (HDL) fraction of the sera were significantly related to fish consumption (P values for men and women were 0.014 and 0.073, resp.). Interestingly, mercury levels were related to serum EPA levels and EPA in the HDL fraction of the sera (P = 0.001) among women (P = 0.005) but not among men. Sex differences in fish species consumed may be an explanation for the observed sex difference. CONCLUSION: Those findings suggest that the health benefit of fish consumption can be maximized by the careful selection of fish species consumed.

Correlation between bone mineral density and body composition in Japanese females aged 18-40 years with low forearm bone mineral density.

OBJECTIVES: To clarify the relationship between bone mineral density (BMD) and body composition in Japanese women aged 18-40 years with low forearm BMD. METHODS: The subjects were Japanese 199 women who had been selected for inclusion in the study based on a low forearm BMD determined at the Annual Women's Health Examination. The subjects' mean (+/- standard deviation) age, body height, body weight, and body mass index (BMI) were 33.5 (+/-4.3) years, 158.1 (+/-5.1) cm, 49.6 (+/-5.7) kg, and 19.8 (+/-2.1), respectively. The BMD of the lumbar spine, total body, and left arm were measured using dual-energy X-ray absorptiometry (DXA). Fat mass (FM), bone-free lean tissue mass (LTM), and body fat percentage (BF%) were measured simultaneously with DXA. RESULTS: In the structural equation model, the standardized regression weights for the path from BMI to BMD of all sites were 0.273-0.434. Conversely, the BF% to BMD of the total body and left arm were -0.192 and -0.296, respectively. In multiple regression analysis, the FM index (FMI) was significantly associated with the BMD of the lumbar spine as a weight-bearing site. The LTM index (LTMI) was significantly associated with the BMD of the total body and left arm as a non-weight-bearing site. CONCLUSIONS: Young females with low forearm BMD had low body weight and BMI. Thinness was shown to be a risk factor for low BMD, in accordance with results reported elsewhere. A gain in body weight may have the effect of increasing BMD, but our results suggest that to increase BMD, the gain in body weight must include increases in LTM, and not FM alone.

Effect of the protein and oil contents on calcium utilization in the diets of female Fischer rats that were fed by three different feeding methods.

We studied the effects of varying the protein and oil contents in the diet and three different feeding methods on the utilization of dietary calcium (Ca) in female Fischer rats. The experimental diets were based on the AIN-76 diet. Rats were fed one of nine experimental diets containing different levels of protein and oil. The experimental diets contained 10, 20 or 40% of protein (milk casein) and 5, 10 or 20% of soybean oil. The three meal feeding methods were ad libitum feeding, pair feeding and adjustable feeding. The experimental diets that were given by prepared feeding were supplemented with a mineral and vitamin solution. The effects of the protein and oil contents in the diet were analyzed by two-way ANOVA. Among rats that were fed ad libitum, the oil content in the diet affected the degree of mineral and vitamin intake. Among the rats fed ad libitum, the oil content in the diet had a significant effect on the level of Ca intake, although it did not have a significant effect on the level of energy intake. For pair feeding, the feeding volume was limited in each group; therefore, there was a significant difference in energy intake and there was no significant difference in Ca intake among each diet group. For adjustable feeding, there was considerable mineral and vitamin intake, which effected the reduction of feeding volume depending on the oil volume in the diet. There were no significant differences in the energy, Ca and other mineral and vitamin intakes among the nine groups that were fed using adjustable feeding. In analyzing two-way ANOVA, in which the parameters were the contents of protein and oil in the experimental diets, there were differences in Ca utilization among rats that were fed using the three feeding methods. This result was shown to reflect on the difference as energy, mineral including Ca, and vitamin intake. However, the protein content in the diet had a significant effect on urinary Ca excretion in all three feeding methods. In addition, it was clear that the intake of protein and oil affected kidney calcification in all three feeding methods. The AIN Experimental Diet Committee reported that kidney calcification was found among rats that were fed the AIN-76 diet and that one of the causes of kidney calcification was the Ca/P ratio in this diet. The protein and oil contents in the diets had significant effects on the degree of kidney calcification among rats that were fed by pair feeding or adjustable feeding. The results of this study suggest that the protein and oil contents in the diet play an important role in kidney calcification.

Long-term follow-up study of health status in population living in methylmercury-polluted area.

At present, it is important to follow-up on the health condition of inhabitants living in a methylmercury-polluted area surrounding Minamata City, paying attention to subclinical disorders not only of the central nervous system, which have been concentrically studied for more than 40 years, but also to other health issues as well. We have performed annual follow-up multiple health examinations on about 1,500 persons of ages more than 40 years old in Tsunagi Town near Minamata City each summer from 1984 to 2004. Case-control studies were designed to estimate the role of risk factors for various health issues using geographical differences to compare the verified patients. The results of the study are summarized as follows: (1) There were no significant differences in the prevalence of diseases associated with Minamata disease (MD) (e.g., liver diseases, renal diseases). (2) Subjective complaints, which were related not only to neurological but also to general complaints were consistently much more common in the polluted area than in the control area. (3) Five percent of the inhabitants who were not certified as MD patients had a high predicting index of MD. They could be affected by methylmercury poisoning. It is important to make a differential diagnosis. (4) No significant differences with respect to ADL by residential area were observed. However, MD patients who stayed in their homes showed some impairments of instrumental ADL. (5) It is important to take into consideration mental distress not only from the physical effects but also from the secondary social damage experienced through MD in these area.

[Factors relating to the conditions and characteristics of mental health among the inhabitants in a methylmercury polluted area].

OBJECTIVES: Little attention has been paid to mental health of inhabitants of methylmercury-polluted areas. The objective of this study was to examine the factors relating to the conditions and characteristics of mental health of inhabitants residing in a methylmercury-polluted area. METHODS: The eligible subjects of the study were inhabitants over the age of 40 years (n=301) living in two fishing village districts that were polluted by high concentrations of methylmercury. The study was conducted in two phases. In the first phase, a structured questionnaire was used to gather information on the current health condition and experience with Minamata disease of each subject through interviews. In the second phase, the General Health Questionnaire (GHQ)-30 was distributed to measure the psychological distress of the respondents. RESULTS: There were 133 (44.2%) study subjects. Factor analysis of the data collected using the GHQ was carried out and five factors that accounted for 57.9% of the total variance were selected. The first factor was labeled "depression and anxiety". Depression and anxiety were significantly associated with self-rated health status, the number of subjective symptoms, monthly outpatient visits and the receipt of compensation. Covariance structure analysis using the Amos 4.0 program demonstrated that depression and anxiety were significantly associated with the subjects' health condition, which in turn was influenced by experience with Minamata disease. CONCLUSION: Depression and anxiety of the inhabitants may be directly caused by the health condition. Further investigations with more precise and detailed measurements are needed to corroborate the causal relationship.

Correlation between forearm bone mineral density and body composition in Japanese females aged 18-40 years.

OBJECTIVE: The purpose of this study was to clarify the relationship between forearm bone mineral density (BMD), body mass index (BMI), and body composition focusing on body fat percentage (BF%) in Japanese females 18 to 40 years old. METHODS: Subjects were 2,280 females 18-40 years old. Anthropometric measurements were taken, and a medical history was obtained by questionnaire, including age at the time of the study and age at menarche. BF% was measured by bioelectrical impedance analysis. Forearm BMD was measured using dual-energy X-ray absorptiometry (DXA). The correlations of BMD with BMI and BF% were analyzed using a structural equation model. RESULTS: The standardized regression coefficients for the path from BMI to BMD and the path from BF% to BMD were 0.538 and -0.184 respectively. The squared multiple correlation of BMD was 0.146. In addition, the standardized regression coefficient for the path from BMI to BF% was 0.896. CONCLUSION: The results showed a positive correlation between BMD and BMI and an inverse correlation between BMD and BF%. At the same time, it was noted that BF% increased with BMI. This indicated that BMD is dependant on BF% in subjects who have a similar BMI. Therefore, this study concluded that it is necessary to take body composition measurements into account when examining the relationship between BMI and BMD, especially in young females.

Differential expression of basement membrane type-IV collagen alpha1, alpha2, alpha5 and alpha6 chains among the histological subtypes of adenoid cystic carcinoma.

Six distinct alpha(IV) chains in the basement membrane (BM) of adenoid cystic carcinoma (ACC) of the salivary gland were immunohistochemically examined by anti-alpha(IV) chain-specific antibodies, and their expressions were compared with the histological subtypes and the expressions of cytokeratin 19 (CK19), cytokeratin 14 (CK14) and alpha-smooth muscle actin (alpha-SMA) and Ki-67. In the BM of normal salivary ducts, alpha1(IV), alpha2(IV), alpha5(IV) and alpha6(IV) chains were continuously stained, but alpha3(IV) and alpha4(IV) chains were negative. In the tubular and cribriform subtypes of ACC, tubules with continuous staining of alpha5(IV) and alpha6(IV) chains showed the biphasic-staining pattern among the expressions of CK19, CK14 and alpha-SMA. However, in cancer-cell nests with discontinuous or negative staining of alpha5(IV) and alpha6(IV) chains, the biphasic pattern was ambiguous. In the solid subtype, the staining of alpha1(IV) and alpha2(IV) chains was discontinuous, the staining of alpha5(IV) and alpha6(IV) chains was negative and the biphasic-staining pattern was unclear. The mitotic activity of cancer cells analyzed by the Ki-67 labeling index was significantly related to the expression of alpha5(IV) and alpha6(IV) chains in the cribriform subtype. These results suggest that BM irregularity with the differential expression of alpha(IV) chains in ACC closely relates to cell proliferation, cell differentiation and histological structure.

Social factors associated with psychological distress among inhabitants in a methyl-mercury polluted area in rural Japan.

Little attention has been paid to the mental health of inhabitants of methylmercury-polluted areas in Japan. This study examined the relationship between one's experience with Minamata disease (MD) (such as compensation issues) and psychological distress. The subjects were 133 (44.2%) of the 301 inhabitants over the age of 40 years living in two fishing village districts along the coast of the Yatsushiro Sea which had been contaminated with methylmercury. Data on the inhabitants' experience with MD, social network factor, health condition and mental health were obtained using questionnaires including the General Health Questionnaire (GHQ)-30. The proportional odds model was used to estimate the adjusted odds ratios of factors associated with a higher GHQ score after adjustment for age, sex and village. MD status based on MD compensation, level of participation in MD patients' groups, and presence of certified MD patients in the family were significantly associated with psychological distress. Although these associations decreased after further adjustments were made taking health condition into consideration, MD status, participation in several sit-ins and the presence of certified MD patients in the family maintained marginally positive association with psychological distress. Further investigations with more precise and detailed measurements are needed to corroborate the relationship between inhabitants' experience with MD and mental health.

Relationship between health status and psychological distress among the inhabitants in a methylmercury-polluted area in Japan.

This study examined the relationship between health parameters and psychological distress among inhabitants of methylmercury-polluted areas in Japan. The subjects were 133 inhabitants over the age of 40 yr living in two methylmercury-polluted villages. Information on demographic factors, health status, and mental health was obtained using questionnaires, including the General Health Questionnaire (GHQ). The proportional odds model was used to estimate the adjusted odds ratios of factors associated with a higher GHQ score after adjustment for age, gender, and district. Very poor self-rated health status, a high number (5+) of subjective symptoms, having monthly outpatient visits and medical house calls, and receiving compensation for methylmercury poisoning were significantly associated with psychological distress. Poor physical condition may lead to the development of psychological distress.

[Health and socio-economic condition of certified Minamata disease patients, 1999].

OBJECTIVES: To clarify the needs and to consider establishing a social support system for patients with Minamata disease (MD), or methylmercury poisoning, by investigating their health and socioeconomic conditions. METHODS: The total number of people certified as having MD in May 1999 by the Kumamoto and Kagoshima Prefecture Government Committees on MD was 2265. We sent two questionnaires to 917 individuals who were surviving at that time, which corresponded to 40.5% of the total number of MD patients. The first survey sought information on the individual's health-seeking behavior, and the second survey was about their socio-economic conditions and requirements for welfare and medical care in the future. RESULTS: The average age among male patients was 68.0 +/- 13.2 yrs (n = 477) and that among female patients was 71.2 +/- 13.0 yrs (n = 440). The response rates were 45.7% (n = 416) for the first questionnaire and 38.6% (n = 354) for the second questionnaire. Among the MD patients, 71.7% judged their health condition to be 'bad' or 'very bad', and 97.4% received medical treatments that included acupuncture or moxacautery and massage. Regarding the activity of daily living (ADL), which includes 'communicating', 'walking', 'eating', 'use of toilet', 'dressing' and 'taking a bath', the rates of 'independent' were relatively low among those under 49 yrs and those over 75 yrs compared with the other age groups. Many individuals emphasized that they had anxiety about their health and health care in the future. CONCLUSION: We concluded that the quality of life (QOL) of MD patients was low. It is important to consider developing a social support system for MD patients.

Serial study on the association between body mass index and hypertension in rural Japanese.

The objective of this study was to examine the association between body mass index (BMI) and blood pressure. Two sets of cross-sectional data were obtained from annual health examinations for adults aged 40 years and over (n=1,327 in 1993; n=1,302 in 2000) in Tsunagi area of Kumamoto Prefecture, Japan. BMI was associated with mean blood pressure and with prevalence of hypertension both in 1993 and 2000. The association was independent of age, smoking status and alcohol consumption. A significant increase in risk of hypertension was found in most categories of BMI 25.0 and above, and a greater than three fold increase in those with BMI of 27 and above compared with those with BMI of 18.5-22.9. Although mean blood pressure and prevalence of hypertension sharply decreased in 2000 compared with that in 1993, BMI was positively and independently associated with increased blood pressure.

Association between body composition and body mass index in young Japanese women.

The National Nutrition Survey of Japan indicated a trend toward a decreasing body mass index (BMI; kg/m2) among young Japanese women. Current studies suggest that not-high BMI often does not correlate with not-high body fat percentage. Recently, the classification of BMI in adult Asians was proposed by the International Obesity Task Force. The addition of an "at risk of overweight" category, BMI as 23.0-24.9, was intended to prevent chronic diseases. We investigated the association between body fat percentage (BF%) and BMI to evaluate the screening performance of BMI focused on individual preventive medicine. The subjects consisted of 605 female college students. The subjects' ages (y), heights (cm), body weights (kg), BMIs, and BF percents with underwater weighing expressed as the means +/- SD were 19.6 +/- 0.5, 158.7 +/- 5.6, 53.8 +/- 7.2, 21.3 +/- 2.4, and 24.9 +/- 4.9, respectively. We defined high BF% as +/- 85th percentile of BF% (29.8%). High-BF% individuals are often not classified into BMI > or = 23.0 because their BMI readings are very broad (18.4-31.7). In comparison to the screening performances (specificity and sensitivity), BMI > or = 23.0 (85.3% and 52.1%, respectively), rather than BMI > or = 25.0 (96.7% and 29.8%, respectively), is recommended for the mass evaluation of fatness. For this reason, the BMI "at risk of overweight" category is characterized as the threshold of increasing the appearance ratio of high-BF% individuals. In conclusion, the BMI > or = 25.0 kg/m2 category is determined as high BF%, regardless of body composition measurement for mass evaluation as a result of quite high specificity. Even so, body composition measurement is necessitated by the individual evaluation of fatness focused on preventive medicine because BMI performed a poor representation of body composition, especially BMI < 25.0 kg/m2 individuals.

Skin problems among fiber-glass reinforced plastics factory workers in Japan.

Two surveys, one in winter the other in summer time, examined the skin problems of the entire manual workers (N=148) from 11 small-to-medium sized fiber-glass reinforced plastics (FRP) factories located in Kyushu, Japan. The workers were exposed to unsaturated polyester resin, including styrene and auxiliary agents such as cobalt naphthenate, hardeners such as methyl ethyl ketone peroxides, glass fiber and dust including shortened glass fiber and plastic particles. Eighty-seven workers (58.8%) reported having skin problems (mainly itching or dermatitis) since they started to work in FRP manufacturing and 25 workers had consulted a physician because of their skin problems; one worker was forced to take sick leave because of his severe dermatitis. History of allergic diseases and shorter occupational period (duration of employment) in a FRP factory were associated with greater probability of having a history of work-related skin symptoms. Workers in factories where dust-generating and lamination sites were located in different buildings were significantly less likely to have a history of skin problems than those in factories where the two sites were located in the same building. Of the 67 workers examined in both seasons closed to double the prevalence of dermatitis was found in summer (23.3%) than winter (13.4%).

Logistic model analysis of neurological findings in Minamata disease and the predicting index.

OBJECTIVE: To establish a statistical diagnostic method to identify patients with Minamata disease (MD) considering factors of aging and sex, we analyzed the neurological findings in MD patients, inhabitants in a methylmercury polluted (MP) area, and inhabitants in a non-MP area. MATERIALS AND METHODS: We compared the neurological findings in MD patients and inhabitants aged more than 40 years in the non-MP area. Based on the different frequencies of the neurological signs in the two groups, we devised the following formula to calculate the predicting index for MD: predicting index = 1/(1+e(-x)) x 100 (The value of x was calculated using the regression coefficients of each neurological finding obtained from logistic analysis. The index 100 indicated MD, and 0, non-MD). RESULTS: Using this method, we found that 100% of male and 98% of female patients with MD (95 cases) gave predicting indices higher than 95. Five percent of the aged inhabitants in the MP area (598 inhabitants) and 0.2% of those in the non-MP area (558 inhabitants) gave predicting indices of 50 or higher. CONCLUSION: Our statistical diagnostic method for MD was useful in distinguishing MD patients from healthy elders based on their neurological findings.

Autonomic nervous functions in fetal type Minamata disease patients: assessment of heart rate variability.

In order to assess the cardiovascular autonomic nervous functions in patients with fetal type Minamata disease (FMD), we investigated blood pressure (BP), and conducted time and frequency domain analysis of heart rate variability (HRV). Subjects were 9 patients in Meisuien recognized as FMD, and 13 healthy age matched control subjects. HRV and BP were assessed after subjects rested in a supine position for 10 minutes. Electrocardiographic (ECG) data were collected for 3 minutes during natural breathing. Time domain analysis (the average of R-R intervals [Mean RR], standard deviation of R-R intervals [SD RR], coefficient of variation [CV]), and frequency domain analysis by fast Fourier transformation (FFT) (power of low frequency [LF] and high frequency [HF] component, expressed in normalized units[nu]) were then conducted. In the time domain analysis, the mean RR of the FMD group was significantly lower than that of the control group. Neither SD RR nor CV showed significant differences between the two groups, but both tended to be lower in the FMD group. In the frequency domain analysis, the HF component of the FMD group was significantly lower than that of the control group. Pulse pressure (PP) was significantly lower in the FMD subjects. These findings suggest that parasympathetic nervous dysfunction might exist in FMD patients, who were exposed to high doses of methylmercury (MeHg) during the prenatal period. Decrease of PP might be due to degenerative changes of blood vessels driven by exposure to high doses of MeHg.