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Biomedical subjects

S Harada

Publications and source records attributed to S Harada.

At least 667 records · Page 37Linked to original sources
PubMed1980

Distant metastasis facilitated by BCG: spread of tumour cells injected in the BCG-primed site.

Tumour metastasis in BCG-pretreated mice was studied using a methylcholanthrene-induced fibrosarcoma in C3H/He mice. When tumour cells were injected into the BCG-primed site, distant metastasis occurred in the lungs and the popliteal lymph node, through this tumour did not metastasize in normal mice. Such metastases were increased in proportion to the number of tumour cells injected into the BCG-primed site, and developed soon after tumour challenge. Concomitant immunity developed well in the mice bearing such metastases, but did not inhibit metastatic growth. Experiments using 125I-labelled SRBC or tumour cells revealed that such cells egressed rapidly from the BCG-primed site. When the tumour was inoculated into the contralateral foot to the BCG-primed site, the incidence and the number of metastases was reduced. Furthermore, BCG infection induced an increase of platelet count. I.v. injection of this tumour induced marked thrombocytopenia in normal mice. Administration of pentoxifylline, a methylxanthine derivative before tumour challenge reduced such metastases. These findings suggest that the changes in peripheral blood, such as increased platelet count and increased release of tumour cells from the injection site, facilitated distant metastasis in BCG-pretreated mice.

Animals↗
PubMed1980

Genetic studies on alcohol-metabolizing enzymes: detection of isozymes in human hair roots.

Human liver alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) play an important role in alcohol metabolism. It has been shown that both enzymes are polymorphic and that different variants may be responsible for individual and racial differences in biological sensitivity to ethanol. However, for lack of a suitable peripheral enzyme source, no information is available regarding family data and the mode of inheritance of ADH and ALDH. Using sensitive micro-methods, we report here the detection of these enzymes and their variant forms in human hair root cells. The isozyme pattern of both enzymes obtained by isoelectric focusing from human liver, cultured fibroblast and hair root cell extracts are presented. Several German, Japanese and Vietnamese families were investigated. ALDH was found polymorphic only in Mongoloid populations. Phenotype distribution in a random Japanese population and families suggest a direct relationship between the absence of ALDH I isozyme and alcohol-induced biological sensitivity commonly observed in individuals of Mongoloid origin.

Alcohol Oxidoreductases↗
PubMed1980

Immunologic features of mice with streptozotocin-induced diabetes: depression of their immune responses to sheep red blood cells.

The immune responsiveness in streptozotocin (SZ)-induced diabetic mice was studied using the immune responses to sheep red blood cells (SRBC) as an indicator system. In SZ-diabetic mice, the weights of such lymphoid organs as the thymus and spleen were significantly decreased with time after SZ administration, whereas the weight of liver was markedly increased. In SZ-diabetic mice, the level of delayed type hypersensitivity (DTH) to SRBC was not lower than that in normal controls in most cases, although the level of DTH was significantly depressed, on occasion, in SZ-diabetic mice. In contrast, antibody-forming activity, measured as the number of plaque-forming cells (PFC), was markedly decreased in SZ-diabetic mice. It seems that antibody production is more profoundly depressed than is DTH in SZ-diabetic mice. The transfer of normal thymus and bone marrow cells into SZ-diabetic mice caused only a partial restoration of PFC activity. When normal spleen cells were transferred into diabetic irradiated mice, proliferation of spleen cells and production of splenic PFC was greatly reduced as compared with normal irradiated mice. Treatment with insulin completely reversed such depression in the transfer system. These findings suggest that the chronic insulin-deficient diabetic state caused a depression and delay in the proliferation and differentiation of lymphoid cells.

Animals↗
PubMed1980

C-19393 S2 and H2, new carbapenem antibiotics. I. Taxonomy of the producing strain, fermentation and antibacterial properties.

C-19393 S2 and H2 are new carbapenem antibiotics produced by a streptomycete. The producing strain was taxonomically studied and named Streptomyces griseus subsp. cryophilus. Cobaltous compounds were necessary for production of the antibiotics. C-19393 S2 and H2 showed a broad spectrum of antibacterial activities with C-19393 H2 being 8 approximately 120 times more active than C-19393 S2. They also exhibited beta-lactamase-inhibiting activities and acted synergistically with ampicillin and cefotiam against clinical isolates resistant to beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1980

C-19393 S2 and H2, new carbapenem antibiotics. II. isolation and structures.

Two new beta-lactam antibiotics, C-19393 S2 (1) and H2 (2), were isolated from the culture filtrate of Streptomyces griseus subsp. cryophilus nov. subsp. The structures were determined by spectral analysis as shown in Fig. 2. The antibiotics have broad antimicrobial activity and strongly inhibit beta-lactamases. The minor product (2) is more stable than cephalosporin C in aqueous solution.

Anti-Bacterial Agents↗
PubMed1980

Liver alcohol dehydrogenase and aldehyde dehydrogenase in the Japanese: isozyme variation and its possible role in alcohol intoxication.

Forty autopsy livers from Japanese individuals were studied concerning alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) isozymes using electrophoretic and enzyme assay methods. A remarkably high frequency (85%) was found for the atypical ADH phenotype. The gene frequencies of ADH22 and ADH32 were .625 and .05, respectively. The usual ALDH phenotype showed two major isozyme bands, a faster migrating (low Km for acetaldehyde) and a slower migrating isozyme (high Km for acetaldehyde). Fifty-two percent of the specimens had an unusual phenotype of ALDH, which showed only the slower migrating isozyme. The usual phenotype was inhibited about 20%--30% by disulfiram and the unusual type up to 90%. Such a high incidence in the Japanese of the unusual phenotype, which lacks in the low Km isozyme, suggests that the initial intoxicating symptoms after alcohol drinking in these subjects might be due to delayed oxidation of acetaldehyde rather than its higher-than-normal production by typical or atypical ADH.

Alcohol Oxidoreductases↗
PubMed1979

Structure of Streptomyces erythraeus lysozyme at 6 A resolution.

A 6 A resolution electron density map has been calculated for a bacterial lysozyme produced by Streptomyces erythraeus. This lysozyme differs from the vertebrate lysozyme in its size, amino acid composition, and specificity. The structure was determined by the method of isomorphous replacement. Three heavy atom derivatives were obtained by soaking crystals of the lysozyme in HgCl2, K2PtCl4, and UO2(NO3)26H2O. The resulting electron density map clearly shows the molecular boundary. The molecule is ellipsoidal in shape with average dimensions 50 A X 35 A X 35 A. High resolution analysis and sequence analysis of the molecule are in progress.

Mercury↗
PubMed1979

Low resolution crystal structures of Taka-amylase A and its complexes with inhibitors.

The molecular structure of Taka-amylase A, an alpha-amylase from Aspergillus oryzae, has been studied at 6 A resolution by X-ray diffraction analysis. The electron density map showed a non-crystallographic three-fold screw arrangement of the molecules in the crystal. The molecule is an ellipsoid with approximate dimensions of 80 x 45 x 35 A and contains a hollow which may correspond to the active center. The inhibitor molecules bind to Taka-amylase A at four different sites, one of which is located in the hollow of the enzyme. The probable position of a thiol group is discussed in connection with heavy atom binding.

Amylases↗
PubMed1979

Alcohol metabolizing enzymes: studies of isozymes in human biopsies and cultured fibroblasts.

Rapid and sensitive micromethods for the study of alcohol dehydrogenase and adehyde dehydrogenase isozymes in skin extracts, cultured fibroblasts and other organs are presented. Possibilities for the application of these techniques to the study of interindividual variations in response to alcohol are discussed. While fibroblasts cultured from a skin biopsy from one Japanese individual revealed a heterodimer (ADH2 2-1) of alcohol dehydrogenase, skin extract from another Japanese showed a homodimer (ADH2 2-2). Up to four isozyme sets for aldehyde dehydrogenase (ALDH) were detected in various human organs and at least three sets were found in skin and fibroblasts extracts. Our preliminary data on liver, stomach, and skin indicate that ALDH is polymorphic and several loci are concerned in the determination of these isozyme sets.

Alcohol Oxidoreductases↗