In order to clarify the acute and subacute toxicity of diborane (B₂H₆, CAS: 19287-45-7) at low concentrations, male ICR mice were exposed to diborane for 1, 2, 4 or 8 h at concentrations of 1 or 5 ppm (phase I study), and for 6 h/day, 5 days/wk, over 2 or 4 wk at concentrations of 0.2 or 0.7 ppm (phase II study). Hematological and biochemical tests, and histopathological examinations of the cornea, nasal mucosa, respiratory tract and lung were carried out. All mice in both studies survived until they were sacrificed. In the phase I study, lung weight increased significantly in mice exposed to 5 ppm of diborane for 8 h. Histopathologically diffuse panbronchiolitis-like lesion was observed in mice exposed to 5 ppm of diborane for 2, 4 or 8 h. In the phase II study, slight infiltration of polymorphous neutrophil was observed mainly in the peri-bronchiolar region in mice exposed to 0.2 ppm or 0.7 ppm of diborane for 2 or 4 wk. In both studies, hematological and biochemical examinations failed to reveal any exposure-related changes. These results suggest that no-observed-effect level of diborane inhalation on the respiratory organs were 1 ppm in acute exposure, but 0.2 ppm of diborane inhalation for 2 or 4 wk seems to be unsafe.

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The focus of this study was satisfaction with health and its relationship to good health practices, symptoms and current use of medication. A self-administered questionnaire was circulated to employees of a railroad company. 3, 639 males aged 18 to 54 (41.4±7.61) were selected. Seven good health practices each scored 1 were not smoking including quitting, not drinking or drinking less than six days a week, exercise more than two days per week, body mass index (BMI) being 20 to 28, total nightly sleeping time between six and nine hours, having breakfast everyday, and not eating between meals. Each score was summed up as health practice index (HPI). We also asked about health satisfaction for the past year, subjective symptoms over the last two to three months, and present medication history. HPI increased significantly in the group aged 45 to 54, this group being satisfied with their health. A decrease in the percentage of eating between meals in the under 35 group, inappropriate BMI in the 45 to 54 group, and regular exercise in the group aged 50 or older was recognized. Health satisfaction was predicted using symptoms, present medication, age and health practice. Standardized discriminant coefficients of symptoms and present medication were 0.672 and 0.610, and they were more associated to health satisfaction than health practice.

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[in Japanese]

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[in Japanese]

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We analyzed factors affecting attacks of subarachnoid hemorrhage (SAH) retrospectively in 411 patients and studied the relation of the attacks with labor. The onset time of SAH has two peaks of the time: one is 7:00 a.m. and the other is between 16:00 and 17:00 in the afternoon. The attacks of SAH during labor were observed in 15.1% of all the patients. It was noted that 66.7% of all the attacks were observed at the time with certain external stress such as working, sporting, sexual intercourse, etc. The number of patients who suffered from attacks during labor with history of hypertension and insomnia were not significantly different compared with those suffered from attacks during other activities, but 40-59 aged men those who have a history of smoking were significantly more in number compared with those that suffered attacks during other activities. Transient increase of blood pressure due to external stress is suggested as an initiative factor of the bleeding during working. Reactivity of the individuals against physical and mental stress (external stress) might be considered to be the major problem, although it remains not to be unexplained whether labor itself participates in the onset of SAH. Regarding the prevention of SAH during labor, new methods of medical examination and health control is required.

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The standards require replaceable dust respirators to be designed so that the wearer can easily check facepiece-to-face fitting at any time. The common practice adopted is an air leakage examination between the facepiece and the face in a negative pressure created by sealling-off inhalation area and breathing-in (called “a negative pressure method”). This method offers only subjective testing made by the wearer himself or herself, no objective testing is possible by the third party including supervisors and hygiene staff. Accordingly, we conducted the practical use test of the Mask Fitting Tester (Model MT-02, Roken type) by letting wearers to use the tester at a sanitaryware plant where workers are well instructed for how to wear respirators and also respirators are used in good care and maintenance. In addition, a questionnaire survey was conducted to investigate how wearers perceive the practical use of the Mask Tester. The following are the conclusions of the study and the survey for the practical use of the Mask Tester. 1) At the first fitness test, when examinees wear the respirator as in the usual manner without given particular instructions, 50% of examinees are found unachieved with the leakage rate of the desired value of 5% or less. 2) All the examinees unachieved were instructed by hygiene staff followed by fitting test to check their leakage rate untill they pass the desired value. After repeating this three times, there were no examinees found unachieved. 3) 88.2% of these examinees could achieve the desired value only by adjusting headbands and correcting the position of facepiece under instructions. No examinees needed filter replacement or replacement or cleaning of inhalation and exhalation valves. This shows that the wearers perform daily check and cleaning of the respirator as per instructions of hygiene staff and that periodical filter replacement is made throughout the plant. 4) However, 11.8% of examinees needed replacement of respirator or face seal cloth or correcting the filter position. Such matters could not be found by the negative pressures method done by wearers until the Mask Testers were employed. In this respect, the fitting test with the tester has been proved to be practical and effective. 5) Majority of the examinees responded that the fitness test using a Mask Tester was practically helpful for correct wearing and maintenance of respirators, showing that wearers highly appreciate the practical use of this tester. 6) Also, the supervisors responded in the questionnaire that this test is very effective not only for the quantitative grasp of the fitting condition but also for improvement of workers understanding regarding dust prevention. All things considered, the fitting test with the Mask Tester is practically useful and effective for the respirator wearing instructions and maintenance, and for the improvement of workers' understanding regarding dust preventions. This plant decided to conduct this fitting test periodically for throughout dust respirator wearers.

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Immunological fecal occult blood test have been proved to be useful in the mass screening for colorectal cancer. Since 1986, we have started annual mass screening by the use of 3-day RPHA method and medical questionnaire for office workers over 40 yr old. During 7 yr, 261 out of 5386 examinees were testing positive for fecal occult blood, a test positive rate was 4.8% and 12 colorectal cancer (7: early, 5: advanced) were found. Among 12 cases, 10 were detected by positive results of RPHA test and 2 by questionnaires of symptoms or family history. The sensitivity and specificity of this method were calculated at 83.3% and 95.3% respectively. But as for advanced cancers, the sensitivity of this method was 100%. 75% of patients with colorectal cancer were over 55 yr old. The predictive value of positive test (PV) were much more higher in subjects with 2 or 3 times test positive (high risk group: PV=14.3%) than in subject with only 1 time test positive (low risk group: PV=0.6%). So it is considered to be reasonable that the high risk group (24% of total test positive) should be immediately undergone further examinations (Ba. enema or colonoscopy), and the low risk group should be undergone re-examinations of 3-day RPHA method. By this system, almost 50% of further examinations will be reduced. In conclusion, 3-day RPHA method with this further examination system is reasonable and efficient for screening of colorectal cancer in office workers, considering the high reliability in cancer detection and decreased further examinations.

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We conducted a survey to investigate medical students awareness of the activities of occupational physicians and their willingness to do postgraduate courses in this field. Those surveyed were fifth grade students in six universities in the Kinki district of Japan in 1993. In analyzing the responses of 368 eligible subjects, the response rate was 68.4% and the following results were obtained. 1) Only one of the 368 subjects expressed a desire to become an occupational physician after graduation, however 24.2% of those surveyed had considered becoming occupational physicians. More female students and, males over the age of 25, had considered becoming occupational physicians. Anxiety about a possible surplus of medical doctors in the near future was a factor that led them to consider becoming occupational physicians. 2) There were few negative responses concerning the activities of occupational physicians, even among those who had not considered becoming occupational physicians. 88.3% of those surveyed complained of a lack of information regarding postgraduate courses. 3) Responses were varied concerning conditions in the practice of occupational physicians. Those who had considered becoming occupational physicians were mostly concerned with the establishment of a system for the acceptance of occupational physicians in industry, while those who had not thought of becoming occupational physicians, considered practicing as occupational physicians as a sideline to regular clinic duties. 4) Having considered the above results and those of other researchers, we concluded that supplying more information related to the activities of occupational physicians and offering further postgraduate training programs in occupational medicine would encourage more medical students to become occupational physicians.

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