In recent years, with the aging of patients with pneumoconiosis, autoimmune diseases as a complication have been observed. One of the reasons for this may be that autoimmune diseases are prone to develop among the elderly.
On the other hand, it has been reported that dust itself, such as silica for example, has adjuvant effect. A review of the recent literature published in Japan and abroad was made to clarify the relationship between pneumoconiosis and autoimmune diseases and the following results were obtained.
1) Disorders which accompany pneumoconiosis: Scleroderma, rheumatoid arthritis, systemic lupus erythematosus (SLE), and disorders of the kidney and liver have been reported. In Japan, about 30 cases of pneumoconiosis accompanied with autoimmune diseases have been reported. In many of the reports, patients with pneumoconiosis and scleroderma have a past history of exposure to silica. In both case studies and case control studies, patients with rheumatoid arthritis and history of silica exposure are prone to develop pnemoconiosis.
2) Immunological studies of patients with pneumoconiosis: As for humoral immunity, elevation of polyclonal γ-globulin, especially IgG, has been often reported together with high positive rate of autoantibodies such as antinuclear antibodies. In cellular immunity, decreased delayed type skin reaction and decreased CD4/8 ratio have been reported. In human leukocyte antigen (HLA) typing the elevated frequency of DR4 has been reported. In the study of BAL increased production of superoxide anion O₂- by alveolar macrophages has been observed.
3) Experimental studies: Silica is well known for its toxicity to cells and also for its adjuvant effect. In the German Democratic Republic, patients with scleroderma and history of long term silica exposure are recognized as patients with occupational disease even though pneumoconiosis is not clearly demonstrated on X-ray film.
It is defficult from this review to nrake a definite conclusion regarding the relation between silicosis and autoimmune diseases. There is a need to repeat this review of the literature on autoimmune diseases and pneumoconiosis in the near future.

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The present study was conducted in order to examine the epidemiologic factors related to work capacity among the elderly. As study area, Ogimi Village in Okinawa Prefecture was selected by reason of the long life expectancy of the inhabitants. Medical examination and interview were conducted on 756 inhabitants aged 65 yr and older. Working status was classified into two groups, that is, working group and non-working group. The association between working status and related factors was examined by using multiple logistic regression analysis. The examined factors were as follows: sex, age, history of apoplexy, history of being down, history of falls, history of fracture, chewing ability, pain, exercise habit, hobby, education, number of family members, alcohol, smoking, food intake frequencies and medical indicators (blood pressure, ECG, Quetlet index, skinfold thickness, grip strength, one-leg test with eyes opened, albumin, total cholesterol, hemoglobin and HDL-cholesterol). The results of the analysis revealed that grip strength and one-leg test with eyes opened had a statistically significant correlation with working status (p<0.01). From the results, maintenance of muscle strength and equilibrium function were found to be the physical conditions related to work among the elderly in the agricultural area.

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In order to determine the optimal conditions of acid hydrolysis for urinary 2, 5-hexanedione (HD) measurement, the effects of urine pH or volume of HCl added to urine and hydrolysis period were studied using gas chromatography-mass spectrometry (GC-MS). When 0.3 ml of concentrated HCl was added to 3 ml of urine, complete hydrolysis to liberate HD was attained 2 h after the start of heating at 100°C for urine from non-exposed subjects. On the contrary, in urine from exposed subjects most of HD was liberated in 30 min at 100°C, suggesting that the urinary substrates converted to HD by acid hydrolysis were different between exposed and non-exposed subjects. It was confirmed that hydrolysis for 2 h at 100°C with 0.3 ml of concentrated HCl added to 3 ml of urine gave the most reliable levels and the greatest amounts of HD in both urine from exposed and nonexposed subjects.
Reference values were determined by the hydrolysis conditions presented here. In 84 males, 52 females, and 136 with sexes conbined the urinary HD levels were 0.35, 0.49, and 0.39 mg/l (geometric mean), respectively. Urinary HD levels determined without hydrolysis (free HD) were less than 0.006 mg/l in 31 control subjects examined. In urine from exposed subjects the amount of free HD was about one-fifth of the total HD (free plus conjugated HD) as determined with acid hydrolysates, although the percentage of free to total HD varied from 0.4 to 28%.
In both urine from exposed and non-exposed subjects, total HD levels determined by GC-FID (flame ionization detector) were in good agreement with those by GC-MS (selected ion monitoring mode), indicating both can be useful for monitoring n-hexane exposure. Two normal urine metabolites, 2-acetylfuran and dimetylthiofene, were found close to HD peak in chromatograms, and were liable to interfere with the HD determination in GC-FID. To avoid the interference, use of non-polar long (50 m) capillary column is recommended for complete separation of HD from the interfering urinary constituents.

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A method using Mahalanobis distance (D²), the general probability distance in multivariate analysis, was studied for evaluating the results of health examination. D² of each subject was computed by a personal computer with a BASIC program, and those whose D² values lay out of 95% confidence interval were considered to be abnormal. In the present study, the mean value and standard deviation come from a normal range of Japanese, and the correlation coefficients between two items were obtained from blood donors in the hospital. These three parameters were necessary for calculation of D². To examine the availability of this method, the data of a health examination on 370 new employees from 18 to 25 yr in age were analyzed with 9 items, including systolic pressure (SBP), diastolic pressure (DBP), serum glutamic oxaloacetic transaminase activity (GOT), serum glutamic pyruvic transaminase activity (GPT), serum gamma glutamyl transpeptidase activity (GGTP), serum total cholesterol (TCHO), serum triglyceride (TG), number of erythrocytes (RBC), and concentration of hemoglobin (Hb). It was shown that the data distributions of GOT, GPT, GGTP, and TG were log normal, and those of the other items were normal. With this method, 39 persons were also judged as abnormal from 46 subjects diagnosed to be abnormal by doctors, and the remaining 7 were missed but could be classed to be normal, as six of them had only slightly high levels of GPT (33-39 IU/l) and/or GGTP (42-57 IU/l), and one had a slightly high SBP (146 mmHg). On the other hand, 41 subjects were selected as abnormal only according to this method of whom 29 demonstrated a significantly higher or lower value of one item, and 12 were due to the imbalance between some items. The individual who showed the unusual ratio of Hb to RBC and low pulse pressure (the difference between SBP and DBP) would be ignored when judged with a common method, but could be found to be abnormal with this method. This new method is therefore effective and valuable in evaluating of health examination data.

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An experimental study of sex hormone on FEP level in rats was conducted to clarify sex difference of FEP level. A total of 42 male Donryu rats were divided into 7 groups; group I (control 1; olive oil injection without castration), group II (control 2; olive oil alone), group III (E_L; estradiol in olive oil, 50 μg/kg·BW), group IV (E_H; estradiol in olive oil, 250 μg/kg·BW), group II' (Pb; Pb 5 mg/kg·BW), group III' (PbE_L; Pb 5 mg/kg·BW+estradiol in olive oil, 50 μg/kg·BW) and group IV' (PbE_H; Pb 5 mg/kg·BW+estradiol in olive oil, 250 μg/kg·BW). Excluding group I, all rats of the 6 groups were castrated. After one week from castration, estradiol was subcutaneously injected 4 times a week, and lead was intraperitoneally injected once a weed for 6 wk.
Estradiol suppressed growth, Ht, Hb value and liver function, but did not show any evident effect on FEP, ALA-U and CP-U. Erythrocyte ALA-D activity in group IV' (Pb+estradiol at high dose) showed a level higher than that in group II' (Pb-treatment alone).

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Replacement of fluid lost due to sweating in a hot working-environment was determined by measuring the body weight of 14 workers (53.6±7.1 years old) 5 times during a working day. They were engaged in repairing and/or maintaining blast furnaces in an environment of 27.9-42.6°C in WBGT. The amount of fluid consumption from a free intake of either green tea and tap water or green tea, tap water and glucose-electrolyte solution (Pocari, Otsuka Pharmaceutical Co., referred to as G-E solution) was compared. The body weight loss during work was 1.70±0.70 kg when free intake of fluids plus G-E solution was allowed, while it was 1.60±0.65 kg when G-E solution was not allowed. Fluid intake with G-E solution was 1.03±0.35 l, and they could rehydrate 61%. Without the G-E solution fluid, was 0.75±0.37 l (47% rehydration). Fluid intake with G-E solution was significantly (p<0.05) larger than that without it. The body weight difference between pre -ad post-work was significant (p<0.001), i.e., it was 0.26±0.52 kg while drinking G-E solution and 0.52±0.53 kg without it. These results suggest that restoration of body fluid after thermal dehydration takes place much faster when consuming G-E solution.

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