Diseases caused by occupational exposure to sensitizing metals including platinum (Pt), rhodium (Rh), nickel (Ni), chromium (Cr), cobalt (Co), gold (Au), mercury (Hg), zirconium (Zr) and beryllium (Be) are reviewed. Allergic reactions induced by the metals are described according to the classification by Coombs and Gell. Metals with unproven sensitizing potential are not discussed if reports on these are either very rare or devoid of convincing evidence for allergic involvement.
The sensitizing metals are haptens which are not themselves able to act as antigens. There is evidence that combination of the metals with circulating or tissue protein gives rise to new antigens. An alternative hypothesis is that these metals interfere with the antigen recognition step of the immune response. Immunomodulatory effects or immunotoxicity of the metals may be also involved in metal-induced hypersensitivity.
Occupational exposure to Pt, Rh, Ni, Cr, and Co causes allergic asthma via type I allergic reaction in which serum from affected individuals shows specific IgE antibodies against mental-human serum albumin conjugates. Some rheumatoid arthritis patients treated with gold salt therapy develop glomeruonephritis, thrombocytopenia, or agranulocytosis, which arise from type II and/or type III allergic reactions. Occupational exposure to mercury causes glomerulonephritis in which involvement of type III reaction is suggested. Type IV hypersensitivity reaction of the skin also takes place following exposure to the metals: allergic contact dermatitis is evoked by exposure to Ni, Cr, Co, Rh, and Hg; cutaneous granuloma is formed by contact with Zr and Be. Be is also a sensitizer of the lungs, resulting in granulomatous disease.
Diagnosis of metal-induced allergic diseases is made on the basis of allergological tests with metal antigens including skin tests, radioallergosorbent test for specific antibody, lymphocyte transformation test, macrophage migration inhibition test, and provocation test.
Atopy is a predisposing factor and smoking is a risk factor for developing metal-induced asthma. Evidence for genetic factors in the development of metal contact dermatitis is conflicting, although animal models implicate genetic factors in skin sensitization with some metals and respiratory sensitization with Be. Skin irritation, forearm injury, complication with atopic dermatitis and concomitant sensitization to other agents are determinants for prognosis of the dermatitis. Epidemiological reports of occupational diseases from allergic reactions to metals in industries are reviewed with respect to prevalence and allergic manifestations.
There is a report on a clinical trial of hyposensitization with Pt in a platinum asthma patient. Predictive methods for evaluating sensitization potential of metals have been developed and new methods, which quantify potential more objectively, are sought.

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In order to clarify the health effects of work stress and possible strategy for its prevention and treatment, we reviewed the literature on work stress as follows:
1) Review was made on 12 major psychosocial work stressors, 4 acute reactions to stress, disease outcome of work stress, measurement methods of those variables, and theoretical models of work stress.
2) Epidemiological studies of the effects of work stressors on cardiovascular diseases, psychological distress and mental disorders in Japan were reviewed. Also, work stress in specific occupations such as software engineers, nurses and female researchers was reviewed.
3) The following strategies for the prevention and treatment of the health effects of work stress were reviewed: i) surveillance of work stress, ii) improvement of psychosocial work environment, iii) education and information dissemination, and iv) reinforcement of occupational mental health services.
Finally, the need for further investigation on the health effects of work stress and on the possible programs for the prevention and treatment in occupational health care system was discussed.

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The effects of smoking and age on the results of hematologic tests were determined in a group of 429 healthy male workers.
The results obtained were as follows:
1) The values of total leucocyte count (×10⁹/l), neutrophil count (×10⁹/l), lymphocyte count (×10⁹/l), monocyte count (×10⁹/l), hemoglobin (g/l), hematocrit, mean corpuscular volume (MCV; fl), mean corpuscular hemoglobin (MCH; pg), and mean corpuscular hemoglobin concentration (MCHC; g/dl) in current smokers were significantly higher than those in non-smokers.
2) Total leucocyte counts and neutrophil counts significantly increased with the number of cigarettes smoked per day in current smokers.
3) Total leucocyte counts, neutrophil counts, and lymphocyte counts significantly increased with Brinkman Index (B. I.) in current smokers.
4) The increase of age was significantly associated with the decrease of erythrocyte counts and the increase of MCV in both current smokers and non-smokers.

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To study the measuring conditions of surface electromyogram for work analysis in the field of industrial health, the effect of electrode fixation, electrode distance and electrode-muscle distance were studied using a mathematical model. The results were as follows;
1) The output waveforms of two electrode fixed models, i.e., parallel-fixed model (two electrodes were fixed in parallel to the direction of the muscle fibers) and transverse-fixed model (two electrodes were fixed in transverse to the direction of the muscle fibers) were compared. The maximum output and rectified integrated output of the parallel-fixed model were 2.59 times and 1.2-1.5 times larger than those of transverse-fixed model, respectively. The high output area of the parallel-fixed model was only one round area, but the areas of transverse-fixed model were four round areas which were wider than the area of the parallel-fixed model. The rectified integrated output of the parallel-fixed model was more affected by the location of neuro-muscular junction than that of transverse-fixed model when the electrodes were fixed near the neuro-muscular junction.
2) The rectified integrated output increased by electrode distance, and the changing rate of the rectified integrated output by electrode distance was particularly large when the electrode distance was shorter than 2 cm. The effect was quite similar between the parallel-fixed model and the transverse-fixed model.
3) The rectified integrated output decreased by electrode-muscle distance, and the changing rate of rectified integrated output by electrode-muscle distance also increased when the electrode-muscle distance was short. The effect of electrode-muscle distance was not so large compared with the effect of electrode distance.

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The concentration of δ-aminolevulinic acid in blood (ALA-B) was determined using high performance liquid chromatography (HPLC). To improve the chromatographic separation and the recovery rate of ALA determination in blood, acetate buffer was used in the reaction mixture of fluorescence derivatization. The detection limit of ALA-B was ca. 2 μg/l at signal to noise ratio of 5, and the analytical recovery was 102.0±4.10% (mean±SD), when 50 μg/l of ALA was added to 7 blood samples (ALA-B levels: 6.5-103.0 μg/l). ALA-B levels in control subjects (n=19) were 5.3±1.4 μg/l (mean±SD) and those in 52 lead workers (blood lead levels (Pb-B): 2.4-86.2 μg/dl) were 15.4±12.2 μg/l (range: 3.1-137.3 μg/l). Standard curve of ALA was linar over a wide range, at least up to 400 μg/l. In the workers, the correlation coefficients of ALA-B vs. Pb-B and ALA-B vs. δ-aminolevulinic acid dehydratase activity (ALA-D) were higher than those of urinary concentration of ALA vs. Pb-B and that vs. ALA-D, especially in the moderate Pb-B level (less than 40 μg/dl, n=35). Unless the urinary concentrations of ALA were not corrected, significant correlation could not be found between Pb-B and urinary ALA in the workers moderately exposed to lead, and the correlation coefficient between urinary ALA and ALA-D was -0.354, while the correlation coefficients of ALA-B vs. Pb-B and ALA-B vs. ALA-D were 0.739 and -0.746, respectively. The effect of lead on bone marrow is more directly indicated by ALA-B than urinary concentration of ALA. Hence, ALA-B is a useful parameter for biological monitoring of lead-exposed workers, especially in the wide range of Pb-B level.

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A questionnaire was mailed to a total of 3, 889 residents 40, 45, 50, 55, 60, and 65 years of age living in 11 municipalities of Hida district, Gifu Prefecture, Japan, to inquire about their life style and health practices. Of the 3, 889 residents, 2, 919 (75.1%) responded to the questionnaire. They were divided into two groups for comparison; the subjects of occupational health services and those of community health services. The subjects of occupational health services at ages 40-55 showed lighter daily physical activity level than those of community health services. However, the subjects at ages 60 and 65 showed equally heavy daily physical activity level in two groups, which indicates that the subjects of occupational health services aged 60 and 65 years are engaged in heavier job at worksite and home. The prevalence of self-rated stress tended to be higher in the subjects of occupational health services. The mean health practice scores tended to be higher for the subjects of occupational health services than for those of community health services at ages 40-55. The percentages of people who had examinations for circulatory diseases were higher among the subjects of occupational health services at ages 40-60 compared with those for the subjects of community health services. Many of the subjects of occupational health services receiving an examination for stomach cancer had obtained the examination service at municipalities provided by local governments. The subjects of occupational health services generally showed superior attitudes toward health care, which suggests that health management for the former is more easily approached than the latter. The authors conclude that health service programs for minor enterprises must be strengthened in the field of occupational health services, and that intervention to those who are not willing to use the health services must be strengthened in the field of community health services.

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