Yoshiki Arimatsu

Experimental study on contact dermatitis caused by dithiocarbamates maneb, mancozeb, zineb, and their related compounds

SummaryAllergenicity of the dithiocarbamate fungicides maneb, mancozeb, zineb and their related compounds were evaluated from the guinea pig maximization test. Extreme to strong potency of allergenicity were revealed for maneb, mancozeb and zineb as well as one of their related compound lime sulphur mixture. But, such degree of allergenicity was not observed in cases of ethylene thiourea and dimethyl dithiocarbamic acid sodium salt. The cross sensitizations among maneb, mancozeb and zineb were estimated to be extreme in potentiality of causing contact sensitization, but there were not so dominant reactions in cases of other combinations tested.

An epidemiological study with risk analysis of liver diseases in the general population living in a methyl mercury polluted area.

STUDY OBJECTIVE--The aim was to determine the actual prevalence of liver disease and to investigate the contribution of various risk factors to liver disease among the population in a methyl mercury polluted area. DESIGN--The study was a population based cross sectional mass screening survey. A case-control study was designed to estimate the role of various risk factors for liver diseases. SETTING--The study was confined to a small rural town 10 km north of Minamata City. SUBJECTS--1406 persons aged 50 to 69 years were examined (78.3% of the total population of this age in the locality). MEASUREMENTS AND MAIN RESULTS--Measurements of liver disease were made on the basis of haematological, physical, and ultrasonographic examinations. Data on liver risk factors were collected by questionnaire, and by measurement of body height, weight (obesity), and hepatitis B surface antigen (HBsAg). The prevalence rate of liver tumour was 0.5% in males, liver cirrhosis was found in 0.5% of males and 0.1% of females, and hepatitis was seen in 5.4% of males and 1.0% of females. Frequency rates of risk factors for liver disease among subjects with obesity were significantly higher in the female patient group, and the frequency rate among subjects with alcoholic drinking habits was significantly higher in the male patient group. The odds ratio of past history of blood transfusion showed the highest value among other related factors (7.73) and the attributable risk for this was very high (87.1%); HBsAg was next in rank (odds ratio 3.04; attributable risk 67.1%). CONCLUSIONS--The prevalence of liver disease in this methyl mercury polluted area was not increased, contrary to what was expected based on the standard mortality ratios. The main risk factors for liver disease in this area appear to be alcoholic drinking habits and a history of blood transfusion.

An Experimental Study on Depigmenting Activity of 4-(p-Hydroxyphenyl)-2-Butanone in C57 Black Mice

An Experimental Study on Depigmenting Activity of 4‐(p‐Hydroxyphenyl)‐2‐Butanone in C57 Black Mice: Depigmenting Activity of HPB in Black Mice: Yoshiharu Fukuda, et al. Department of Public Health, Kumamoto University School of Medicine—The authors previously reported three cases of occupational leukoderma in workers engaged in a 4‐(p‐hydroxyphenyl)‐2‐butanone (HPB, Raspberry Ketone) manufacturing process. These cases suggested that HPB might be a chemical causing the leukoderma and it had depigmenting activity. The purpose of this study is to evaluate the depigmenting activity of HPB by using laboratory animals. HPB, its two crude products and monomethyl ether of hydroquinone as the positive control were topically applied to the dorsal surface of C57 black mice. Depigmentation was shown in black mice to which HPB and its crude products were topically applied but the effect produced by these chemicals was weaker than that seen with monomethyl ether of hydroquinone. Though evidence of a reduction in melanocytes and pigmentation was not documented in the microscopic analysis, spectrophotometric assay showed a decrease in melanin content in the hair of mice to which HPB and the crude product had been applied. The results indicated a depigmenting activity of HPB and supported the conclusion that the leukoderma which we reported in a companion paper was induced by exposure to HPB and/or its crude products. Nevertheless, the potential of this depigmenting activity is so weak that the development of leukoderma due to these chemicals may be limited to those who are occupationally exposed.

Quantification of α-methylene-γ-butyrolactone extracted from different parts of Alstroemeria wilhelmina and evaluation of it's antigenicity using the guinea-pig maximization test

To detect the type of contact dermatitis caused due to the handling ofAlstroemeria wilhelmina, 1% α-methylene-λ-butyrolactone (α-MBL) dissolved in physiological alien and a five-fold diluted saline solution of original extracts of flowers, leaves and stems of the flower were applied to guinea-pigs for extracts were applied to the animals as the challenge treatment in compliance with the guinea-pig maximization test (GMT). As a consequence, not only primary irritant dermatitis was observed, but also delayed type allergic contact dermatitis due toAlstroemeria wilhelmina was observed. α-MBL determined in the extracts using high-performance liquid chromatography (HPLC) was found to be the biochemical material cause of the contact dermatitis. the flower region contained α-MBL in the highest concentrations compared with those of the leaves and stems. Therefore, the quantification of α-MBL in the extracts was concluded as being a useful evaluating method for contact dermatitis due to the handling ofAlstroemeria.

Experimental study of contact dermatitis due to alstroemeria in guinea pigs

Contact allergy from handling alstroemeria (Alstroemeria) has been widely observed in horticulturalists and florists (1–5). α‐methylene‐γ‐butyrolactone (α‐MBL) has been shown to be the causative agent (6, 7). In the present study, delayed‐type contact dermatitis due to alstroemeria was evaluated using the guinea pig maximization test (GMT) (8), and the intensity of allergic reactions was investigated by quantifying the contents of α‐MBL in different parts of alstroemeria by high‐performance liquid chromatography (HPLC) (9).

Follow-up studies on the distribution of haemoglobin levels in female farm workers.

Haemoglobin concentrations in about 1000 women agricultural workers in Japan were measured every year, except in 1972, during the period 1967-77. Improvements were noted in the course of this investigation, and these were predominantly associated with the fact that those in the study community began to pay attention to the problem of low haemoglobin levels and to improve their diet, with an increase in daily food intake, particularly of animal protein and iron. In addition, a marked decrease in anaemia caused by hookworm also played an important role. In this paper, the change in haemoglobin concentration during the period of study are described and the aetiology is discussed.