We examined the effect of IL-12 and IL-18 on bactericidal activities of mouse peritoneal cell (PC) against Mycobacterium leprae (M. leprae). We demonstrated that IL-12 and IL-18 synergistically induced the NO-dependent bactericidal activity of PC by stimulating Natural Killer (NK) cells and T-cells through IFN-γ production. IL-12 and IL-18 induced host cell death through NK-cells and T-cells. Therefore, IL-12 and IL-18 play an important role on direct killing of intracellular M. leprae and on indirect killing of them through inducing host cell death.

View full abstract

Embryonic stem (ES)cells are pluripotential cells, and enable us to study mechanisms of cell differentiation. Gene disruption of ES cells by homologous recombination is to be clear the function of targeted genes. Recently, it has been reported that bone marrow hematopoietic stem cells have a potential to differentiate into neuronal cell, muscle cell, liver cell, epidermal cell, and also epithelial cell lineages. Moreover, cloned animals from somatic cell nuclei were produced.
Here, we show osteoclastogenesis, and endothelial cell-genesis from single ES cell, and discuss the possibility for organogenesis in vitro. Furthermore, we would like to summon to understand usefulness and dangerousness of the regenerative medicine.

View full abstract

Our previous paper reported that the intracellular ATP content in cells of M. leprae consistently increased in the medium containing adenosine after 4-6 weeks of cultivation and decreased thereafter. The reason why ATP generation ceased 4-6 weeks after cultivation is not clear.but it was determined that the termination in ATP generation was not a result of deterioration in the culture medium during cultivation because a renewal trial of the old culture medium by freshly prepared culture medium had no effect further maintenance or progressive increase in ATP generation. From the results obtained in a renewal trial of the culture medium, I would like to speculate that the reason why M. leprae cells do not multiply in vitro might be due to the characteristic property of the cell wall of M. leprae, i.e., fragility.

View full abstract

Recent studies have revealed that the Mycobacterium leprae genome contains many pseudogenes. This short review summarizes the structural features of the M. leprae genome and genes.

View full abstract

Peripheral nerve biopsies from 10 leprosy patients(6 tuberculoid patients and 4 lepromatous patients) were studied morphological aspect. Light microscopical examination showed that the perineurium was markedly thickened by infiltrated cell in tuberculoid type and Mycobacterium leprae in lepromatous type. Schwann cell markedly decreased in number, and nerve fiber disappeared without regeneration in severe cases. In mild cases, subperineurial edema was present. The nerve fiber density was normal or mild decreasing. Ultrastructural examination showed abnormality of basal lamina on perineurial cells. The basal lamina of the perineurium completely disappeared in severe cases, and showed splitting even if the perineurium had normal structure in light microscopy. Both type of leprous neuropathy had same pathological changes in regard to abnormality of the basal lamina. There were many M.leprae presented in Schwann cells, fibroblasts and perineurial cells on the nerve of lepromatous patients, although few M.leprae in the nerve of tuberculoid patients. This study provides that these abnormality of perineurium is characteristic in both types of leprous neuropathy.

View full abstract

The Leprosy Prevention Law was abolished at the end of March, 1996. Since medical insurance for leprosy started in April, 1996, dermatologists in clinics have to take care of leprosy patients. However, dermatologists have not learned enough about leprosy, and only a few of them are familiar with it.
Japanese patients newly diagnosed with leprosy in Japan have decreasing, and patients who come from foreign countries to work in Japan have more important in leprosy control. Therefore, it is important to educate dermatologists about leprosy.
Recently, diagnostic guides including information about network systems have become available in book stores. It is possible to obtain all kinds of information about leprosy from the network systems.

View full abstract

For the effective treatment of leprosy, we should consider that (1)more time is needed for the elimination of bacilli than ordinary bacterial infection, (2)bactericidal therapy often induces host immunity called reactions, (3)rapid treatment is needed for the reactions. Last year, ad hoc committee of Japanese Leprosy Association recommends standard treatment protocol of leprosy in Japan, which is a modification of World Health Organization's multidrug therapy. For multibacillary(MB)with bacterial index (BI≥3)before treatment, 2 years treatment by rifampicin, dapsone and clofazimine (MDT/MB) is necessary. When BI decrease is not satisfactory(BI value decrease<2 steps, or final BI≥3)after 2 years, MDT/MB should be continued until BI negativity and loss of active lesions. Theoretical background of our proposal is described.

View full abstract