Hitoshi Kasuga

An Occupational Hazard for Pathologists and Pathology Technicians in Japan

The incidence of pulmonary tuberculosis among pathology workers in Japan is elevated, presumably due to frequent exposure to tubercle bacilli in the work place. To demonstrate the etiological significance of the association between this disease and occupation epidemiologically, a questionnaire survey was performed to assess the incidence of pulmonary tuberculosis among 1,201 pathologists and 1,187 pathology technicians throughout Japan. Pathology department workers other than pathologists and technicians, such as secretaries (n = 207), and workers in university departments of preventive medicine and public health (n = 732) served as control groups. While non‐occupation‐related tuberculosis was found in both departmental groups with nearly equal incidence, the incidence of pulmonary tuberculosis among pathologists and pathology technicians after engagement in their current specialist work was significantly higher than that in the control groups (odds ratio = 6.08–10.98). The incidence of disease among pathology technicians who assisted in autopsies was markedly higher than among those not involved in autopsies (odds ratio = 6.65). This elevated incidence was significantly related to the duration of work in pathology activities, and showed little change over the last decade. These findings indicate that specific environmental conditions in pathology departments, particularly autopsy of cadavers harboring active tuberculosis, constitute a serious occupational hazard. Acta Pathol Jpn 40: 116–127, 1990.

Urinary hydroxyproline to creatinine ratio as a biological effect marker for exposure to NO2 and tobacco smoke

In order to study the relationship between NO2 exposure and effects, we monitored personal NO2 exposures and the hydroxyproline to creatinine ratio in urine of about 800 women in two communities near Tokyo. Monitoring was conducted during two seasons, winter and summer 1982. The hydroxyproline to creatinine ratio (HOP:C) was determined from urine samples collected in the early morning. Daily average personal NO2 exposures (ENO2) were measured by using a filter badge. In both seasons, HOP:C was found to have significant correlation with ENO2 and active and passive smoking. In addition, subjects living near major roads had significantly higher HOP:C levels in the summer compared with those living far from them. We hypothesize that these higher HOP:C levels in the summer were due to higher air exchange rates resulting in infiltration of automobile exhaust into homes. ENO2, however, did not correlate with either the distance of the subjects house from major roads or with the amount of smoking. Stepwise multiple regression analysis revealed that HOP:C could be predicted by personal NO2 exposures and smoking variables with a high level of confidence.

Behavior of urinary hydroxyproline and cigarette smoking effect in silicosis.

This study was conducted through regular pneumoconiosis examination according to the law on 1, 096 employees of medium and small-sized ceramic enterprises in Tokai district in 1981-82.Interview examination with BMRC questionnaire, X-ray examination and measurement of urinary hydroxyproline to creatinine ratio (HOP ratio) were carried out in order to elucidate the relationship between silicosis and urinary HOP ratio and to demonstrate the effect of smoking on pneumo-fibrosis. Grade of silicosis was classified into five types (0 to 4) based on the Japanese Classification of Radiographs of Pneumoconioses.In evaluating the behavior of urinary HOP ratio, when smoking factor is added in the early grade of pneumofibrosis (type 1 and type 2), collagen decomposition rate is rapidly repressed and fibroplastic conditions develop to the final grade as type 3 and type 4, although smoking itself does not seem to induce pneumofibrosis.To exclude the effects of smoking, nonsmoking group was used for measurement of HOP ratio by grade. The HOP ratio in type 0 was lowest and HOP ratio increased in the order of type 1 and type 2. The turning point was found in type 2 and their HOP ratio decreased one after another.The turning point shifted from type 2 to type 3 in the case of non-smokers without any index symptoms by BMRC questionnaire and also shifted to type 1, in the case of non-smokers with them. Shifting of turning point suggests that index symptoms also promote fibroplastic activities.

The significance of guanine in house dust and its application to epidemiological study

Abstract House dust has been incriminated as an important causative allergen in bronchial asthma. Guanine is contained in living mites and their feces. A quantitative method to determine the level of guanine in house dust was improved. Since guanine makes up 0.3% of the living mite and the guanine concentration in house dust correlates highly with the number of mite present (r=0.704), it is suggested that the guanine level in house dust could be used to as a marker of mite allergens in epidemiological study.