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Biomedical subjects

N Tamura

Publications and source records attributed to N Tamura.

At least 307 records · Page 17Linked to original sources
PubMed1983

Interaction of C4-binding protein with cell-bound C4b. A quantitative analysis of binding and the role of C4-binding protein in proteolysis of cell-bound C4b.

Purified C4-binding protein (C4-bp) was shown to bind to cell-bound C4b by radioactive tracer techniques. With EAC4 bearing greater than 3,000 C4b-molecules/cell, the number of C4-bp molecules bound was directly proportional to the number of C4b molecule on the cell surface; EAC4 bearing less than 3,000 C4b-molecules/cell bound a very small amount of C4-bp. Scatchard analysis of binding of C4-bp indicated an equilibrium constant of 4.6 X 10(8) L/M and a maximum of 0.43 C4-bp molecules bound per C4b molecule, equivalent to an average of one molecule of C4-bp per two or three molecules of C4b. Fluid-phase C4b inhibited the binding of C4-bp to cell-bound C4b in a dose-dependent manner, whereas native C4 had little effect. C2 inhibited this binding and also released C4-bp from EAC4,C4-bp. However, C2 was 27 times less effective than unlabeled C4-bp on a molar basis and a considerable amount of C4-bp remained bound to C4b on the cell surface even in the presence of a large excess of C2. We also examined the cofactor activity of C4-bp in the cleavage of cell-bound C4b by C3b/C4b inactivator (I). Cleavage of the alpha' chain of C4b on the cell surface by I alone was incomplete and an intermediate cleavage product, alpha-75, was observed. When C4-bp bound to C4b on the cell surface, the alpha' chain of the C4b cleaved into three fragments, alpha 2, alpha 3, and alpha 4. The alpha 3, alpha 4, beta, and gamma peptides (C4c) were released into the fluid phase, and the alpha 2 fragment (C4d) remained linked covalently to the cell membrane via an ester bond. In some situations, therefore, C4-bp enhances the proteolytic activity of I on cell-bound C4b.

Animals↗
PubMed1983

Alteration of fecal bacterial flora following oral administration of bifidobacterial preparation.

The fecal bacterial flora was examined in multiple stool specimens from 14 subjects with gastrointestinal disorders before, during and after the oral administration of bifidobacterial preparation (BBG, viable B. breve and B. bifidum, 3 X 10(9) or 6 X 10(9) per day) for 2 or 3 weeks. Enumerations of fecal bacterial flora showed no conspicuous alterations in total anaerobic bacterial counts during the BBG therapy, however the total number of bifidobacteria in feces increased significantly, and of E. coli and other aerobacteria showed a tendency to decline. The administered B. breve and B. bifidum were recovered in the feces at a concentration of 10(8)/g and of 10(7) to 10(8)/g, respectively. Both species continued to be excreted over 2 weeks after completion of the medication in the feces at concentrations of 10(6) to 10(7)/g and of 10(5) to 10(6)/g respectively, and diminished rapidly in 5 patients and continued at essentially the same level as during the medication in 6 patients. During the treatment the pH, urease activity and ammonia content in feces became lowered and showed a rerise after therapy. Symptomatic discomforts including abdominal distension and pain, anorexia, edema and fever of undetermined origin were reduced during the therapy. Urinalysis, hematological examinations and blood biochemical tests including blood ammonia level, however revealed no significant change.

Administration, Oral↗
PubMed1983

Synthesis and structure-activity relationships of carbapenems related to C-19393 H2.

By applying the synthetic process reported in our previous paper, we synthesized new carbapenems having various (substituted) thio and alkoxy groups at the C(3) position and 1-hydroxy-1-methylethyl and analogous groups at the C(6) position with cis- and trans-stereochemistry; the in vitro antibacterial and beta-lactamase inhibitory activities of these new carbapenems were examined. Compared to C-19393 H2, some of these compounds (e.g., 11A-a-3 approximately 5) showed improved in vitro antibacterial activity especially against Pseudomonas aeruginosa; they showed a strong beta-lactamase inhibitory activity as well. Two noteworthy effects of substituent variation at the C(6) position on the activities were observed: 1) the trans-configuration caused a definite loss; and 2) introduction of 1-hydroxycyclobutyl and 1-hydroxy-1-methylpropyl groups in place of the 1-hydroxy-1-methylethyl group caused a diminution. The carbapenem (13A-a-2) with an alkoxy group at the C(3) position had a marked decrease in activity compared to the corresponding thio-substituted carbapenem (11A-a-12).

Indicators and Reagents↗
PubMed1983

Demonstration of beta 1H globulin in pemphigus.

beta 1H globulin is a plasma protein which regulates the biologic activities of the major fragment of the 3rd complement component, C3b. The role of beta 1H globulin in pemphigus was investigated using immunofluorescence in the present study. Lesional skin biopsies from patients with confirmed pemphigus demonstrated in-vivo deposition of beta 1H in addition to C3 in all of four biopsies. Eight serum samples containing C3 fixing intercellular antibodies were then tested for the capacity to fix beta 1H and other complement components. All eight pemphigus sera showed fixation of beta 1H to the intercellular areas of normal human skin. C1q and C4 fixation by pemphigus sera was also demonstrated in 7 of 8 sera, respectively. The experiment using C2-deficient serum indicated that the fixation of beta 1H by intercellular antibodies requires the activation of the classical complement pathway. These data suggested that beta 1H, a co-factor of C3b inactivator, plays a role in the in-vivo regulation of complement activity and supplies additional evidence for the participation of complement system in the pathogenesis of pemphigus.

Antibody Specificity↗
PubMed1983

Inhibition of classical C5 convertase in the complement system by factor H.

This paper described the influence of factor H on the haemolytic activity of the classical C5 convertase. Factor H showed little effect on the interaction of C5 with EAC1,4b,2a,3b cells bearing low numbers of C3b sites, but displayed the inhibitory effect on the interaction of C5 with the intermediate cells bearing high numbers of C3b sites. The higher the number of C3b sites on the cells, the greater the degree of the inhibition by factor H. The inhibition by factor H was accompanied by the inhibition of consumption of C5 from the fluid phase, indicating that factor H inhibits the activity of C5 convertase, not the binding of activated C5 to the cells.

Animals↗
PubMed1983

Difference in polynucleation of cultured cells from human mammary tumors and normal mammary glands on treatment with cytochalasin B.

In order to study the biological nature of various mammary tumors, differences in the formation of polynuclear cells after the administration of cytochalasin B were investigated in cultures of human mammary tumors and normal mammary gland. When cytochalasin B was applied to the cultures, polynuclear cells increased in all cancer cases (6.1% on average), but relatively little effect was seen in cases of benign tumors and normal mammary gland (less than 1.1% on average). From these results, it appears that the difference in polynucleation on treatment with cytochalasin B may be useful as a biological means to distinguish human malignant and benign mammary tumors.

Breast↗
PubMed1983

Hidroacanthoma simplex with invasive growth.

Hidroacanthoma simplex is a benign tumor of the skin, macroscopically resembling seborrheic keratosis or Bowen's disease, and histologically revealing intraepidermal focal growth of epithelial cells. A case of hidroacanthoma simplex with a malignant portion is presented in this report. The present case revealed mostly histologic characteristics of hidroacanthoma simplex, but the central portion of the tumor showed downward invasive growth with increased cellular atypia. The malignant change of hidroacanthoma simplex is discussed in relation to eccrine porocarcinoma (malignant eccrine poroma).

Humans↗
PubMed1982

Anti-albumin antibodies in sera of patients with gastro-intestinal disease.

Sera from 111 patients with various gastro-intestinal (GI) diseases were studies for the presence of antibodies to human serum albumin (HSA), bovine serum albumin (BSA) and ovalbumin (OA) by passive haemagglutination assay. The antibody titre to BSA was higher than that to HSA or OA. The anti-BSA antibody was demonstrated in upper GI diseases i.e. esophageal cancer, gastric ulcer, gastric cancer and duodenal ulcer, and not in lower GI disease i.e. Crohn's disease, ulcerative colitis and colon cancer. Both the mean titre and the incidence of the anti-BSA antibody tended to be higher in women than in men, and the titre was in a positive correlation with serum gamma-globulin levels. Sephadex G-200 column chromatography revealed that the anti-BSA antibody was widely distributed between void volume and 7S fraction.

Adolescent↗
PubMed1982

Anti-albumin antibodies in sera of patients with liver disease.

We used passive haemagglutination assay to examine sera from 77 patients with various liver diseases for the presence of antibodies to human serum albumin (HSA), bovine serum albumin (BSA) ans ovalbumin (OA). The antibody titre to BSA was higher than that to OA or HSA. Of the examined diseases, in chronic active hepatitis and liver cirrhosis, the titre and incidence of anti-BSA antibody were highest. There was a positive correlation between anti-BSA antibody and serum gamma-globulin level. Sephadex G-200 column chromatography and immunoelectrophoresis revealed that the anti-BSA antibody belonged to the IgM class.

Adult↗