Biomedical subjects
Publications and source records attributed to K Kawatsu.
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The pathogenicity of two substrains (HO-R and HO-S) of cultivated murine leprosy bacilli was examined by intraperitoneal inoculation to various strains of mice (C3H, KK, BALA/c, DDD and C57BL/6). HO-R (Rough Form) was first isolated on 1% Ogawa's egg yolk medium from the leprous lesions produced by original Hawaiian strain (H bacilli). HO-S (Smooth Form) was dissociated in vitro during the 9th to 15th subculture of HO-R on the same kind of medium. In all the mice tested, intraperitoneal inoculation with HO-R bacilli produced progressively severe visceral lesions in the manner similar to H bacilli harvested from subcutaneous leproma. The only exception was, however in DDD strain of mice H bacilli produced only slight visceral lesions even in the later stage of infection. HO-S was much lower in the pathogenicity than the above two strains of murine leprosy bacilli. Visceral lesions produced by intraperitoneal inoculation with HO-S used to be very slight in all the strains of mice except BALB/c. BALB/c strain mice were highly susceptible to intraperitoneal as well as subcutaneous infection with HO-S. From the above observations, it is concluded that the characteristic features of pathogenicity of cultivated murine leprosy bacilli, such as mouse strain differences, are all the same regardless of infection route.
This paper deals with the pathogenicity of cultivated murine leprosy bacilli from rough colonies of Hawaiian-Ogawa strain in mice. This strain was isolated by Ogawa, in 1970, on Ogawa's 1% egg yolk medium [1], from mice previously inoculated with Hawaiian strain of murine leprosy bacilli which has been maintained by passages from mice to mice. The pathogenicity of Hawaiian-Ogawa strain was found to belong to the same pattern as Hawaiian strain when the subcutaneous inoculation test was carried out in C57BL/6 and C3H mice, the former being representative of the benign type and the latter being representative of the malignant type. In KK mice of the intermediate type with Hawaiian bacilli, however, Hawaiian-Ogawa bacilli produced the lesions with malignant features in almost all the male mice, while the female mice were divided into two groups roughly half showing the intermediate or malignant type. In DDD mice of the benign type with Hawaiian bacilli, some cases of the male mice showed the malignant features, whereas almost all the female mice were of the benign type in the same experimental conditions. The pathogenicity of Hawaiian-Ogawa bacilli in mice did not revert into that of Hawaiian bacilli even after serial mouse passage. There are slight but definite differences in the mouse pathogenicity between Hawaiian-Ogawa and Hawaiian strains.
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Comparative observations were made on the development of experimental murine leprosy in various inbred strains of mice, including nude mice of congenital thymic aplasia. The susceptibility of these strains of mice to murine leprosy bacilli was evaluated by the development of leproma at the subcutaneous infection site and also by the involvement of visceral organs. Nude mice developed a much more severe disease than C3H mice which is the representative of the malignant type. Their high sensitivity was also demonstrated in the case of intraperitoneal infection. The observations in nude mice and other mouse strains confirmed our concept that experimental mouse leprosy can be classified into three clinical types, benign, intermediate and malignant, and suggested that such mouse strain differences are related with their cell-mediated immunity.
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Inoculation of M. leprae were made into the both hind feet at a dose of 4.8 x 10(6) bacilli per foot in order to determine the susceptibility to M. leprae of SCID mice which is severely deficient in both T- and B cell immunity. SCID mice was found to have an extremely high susceptibility to M. leprae, and the progress of infection observed in the SCID mice were shown a rapid systemic spread of infection at the all over the tissues as well as the growth of the leprosy bacilli at the site of inoculation. Therefore, SCID mice can be used as a suitable multibacillary model for the study of leprosy.
A comparative study on the usefulness of Kawatsu's silver impregnating staining method compared with S-100 protein ABC technique for the differential diagnosis of tuberculoid leprosy was carried out. The results of neurohistological examination obtained from both methods were almost the same. It can be said that Kawatsu's method is useful and cost-effective, and thus suitable for practical use in developing countries.
The multi-sections, which were stained by Fite method, of skin biopsies taken from twelve active BT cases were examined under the guidance of special stains for demonstration of nerve components. All cases were AFB positive. Bacilli were found in infiltrated nerves in 11 cases, of which, in 7 cases, bacilli were detected in nerve fragments within epithelioid cell granuloma. And bacilli were seen in arrector pili muscles in 2 cases. No bacilli were detected in other sites. Since the survival of M. leprae in nerves is one of the reasons causing relapse, this paper suggests that it would be better to treat active BT cases with multibacillary regimen recommended by WHO even though smear-negative.
One of the most important unsolved questions in epidemiology of leprosy is the highly uneven geographic distribution of the disease. There are many hyperendemic "pockets" in endemic countries. Little is known about the reasons why leprosy is hyperendemic in these areas. We conducted, therefore, a series of epidemiological studies on Mycobacterium leprae infection and prevalence of leprosy in North Maluku district, Maluku Province, Indonesia where leprosy is highly endemic. It was found that considerable number of general inhabitants are seropositive to various mycobacterial antigens and 27% of the villagers were carrying leprosy bacilli on their surface of nasal cavity. These results suggested the importance of M. leprae in the residential environment in infection of the leprosy bacillus and the resulting transmission of the disease. Based on these observations, we conclude that new preventive measures are essential for global elimination of leprosy in addition to early diagnosis and multidrug therapy (MDT).
Ten samples of commercial blue mussels (Mytilus edulis) from Japan were analyzed for domoic acid by an indirect competitive enzyme immunoassay (idc-EIA) based on an anti-domoic acid monoclonal antibody. Domoic acid was found in all samples at low concentrations (0.11-1.81 ng/g mussel tissue). The presence of domoic acid was confirmed by liquid chromatography coupled with immunoaffinity chromatography using an anti-domoic acid monoclonal antibody as ligand. To our knowledge, this is the first reported detection of domoic acid, a causative agent of amnesic shellfish poisoning, in Japanese mussels.
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