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K Nakamuro

Publications and source records attributed to K Nakamuro.

13 recordsLinked to original sources
PubMed1978

Comparative studies of chromosomal aberration and mutagenicity of the trivalent and hexavalent chromium.

The comparative cytogenetic and mutagenic effects between trivalent and hexavalent chromium were investigated. Five chromium compounds, K2Cr2O7 and K2CrO4 containing Cr6+, and Cr(CH3COO)3, Cr(NO3)3 and CrCl3 containing Cr3+, were examined for their ability to induce chromosomal damage in cultures of human leukocytes, for their reactivity with DNA by a rec-assay system and for mutagenicity in the E. coli Hs30R test system. Chromosome-breaking activity was significantly higher for the compounds with hexavalent than trivalent chromium, the efficiency being in the decreasing order K2Cr2OM greater than K2CrO4 greater than Cr(CHCOO)3 greater than Cr(NO3)3, CrCl3. In the rec-assay and mutation assay, hexavalent (K2Cr2O7 and K2CrO4) and trivalent Cr(CH3COO)3) compounds gave positive results, their mutagenic potential being higher in the same order of clastogenic magnitude.

Cells, Cultured↗
PubMed1978

Reactions of rabbit antisera to human beta2-microglobulin (beta2-M) with platelets.

Reactions of rabbit antisera to human beta2-M against human platelets and man-mouse hybrid cells were studied by MA tests and cytolysis tests. Evidence is presented that the beta2-M act as species-specific cell surface antigens, some of which are most likely shared by cell surface proteins determined by genes on chromosomes other than the chromosome 15.

Absorption↗
PubMed1977

Common antigenic structures of HLA antigens. VII. Selective combination binding of beta2-microglobulin with HLA large component in cultured human cell lines.

The intracellular distribution of human beta2-microglobulin was examined in human cell lines (a Burkitt lymphoma cell line, a B-lymphoid cell line and an epighelial-like cell line). Freshly harvested cells were mechanically disrupted and separated into the nuclear, cell-membrane and cell-sap fractions. Nearly 90 per cent of the total beta2-microglobulin was recovered in the cell-membrane and cell-sap fractions. The cell-membrane fraction contained 75-88 per cent of the beta2-microglobulin recovered. The rest was in the cell-sap fraction. Most, 84-91 per cent, of the beta2-microglobulin in the cell-membrane fraction was present combined with membrane fraction was present combined with membrane components of about 38,000 daltons that carried the xenoantigenic activity characteristic of the HLA large component. These membrane components did carry HLA alloantigenic activity. No other membrane components were involved in binding beta2-microglobulin. The beta2-microglobulin in the cell-sap fraction was present in the unbound state. Thus, in the cell lines examined, the membrane component which was combined with beta2-microglobulin appeared to be exclusively the HLA large component and no larg excess of beta2-microglobulin over the HLA large component was found.

Beta-Globulins↗
PubMed1976

Studies on selenium-related compounds. V. Cytogenetic effect and reactivity with DNA.

Five selenium compounds, Na2Se04, H2Se04, Na2Se03, H2Se03 and Se02, were tested for their capacity to induce chromosome aberrations in cultured human leukocytes and for their reactivity with DNA by a rec-assay system and inactivation of transforming activity in Bacillus subtilis. Chromosome-breaking activity was significantly higher for the compounds with four-valent than with six-valent selenium, the efficiency being in the decreasing order H2S03 greater than Na2Se03 greater than Se02 greater than H2Se04 greater than Na2Se04. Rec assay using B. subtilis with different recombination capacities suggested that damage to DNA was produced by selenites but not by selenates. The reactivity of selenites with DNA was also indicated by a significant loss of transformation of the tryptophan marker of B. subtilis DNA treated with H2Se03 and Se02.

Adult↗
PubMed1975

Common antigenic structures of HL-A antigens. VI. Common antigenic determinants located on the 33,000 Dalton alloantigenic fragment portion of papain-solubilized HL-A molecules.

HL-A 33,000 Dalton fragments were isolated from three papain-solubilized HL-A preparations carrying different HL-A allospecificity by the dissociation induced in the reaction with rabbit antibodies to HL-A 11,000-Dalton fragment (i.e. human beta2-microglobulin). By assaying the binding activity with rabbit antisera against papain-solubilized HL-A molecules and against each of the HL-A component fragments and also with a battery of HL-A alloantisera, the 'antibody-dissociated' 33,000-Dalton fragments were shown to retain not only the HL-A alloantigenic determinants but also the HL-A common antigenic determinants that are native to the 33,000-Dalton fragment portion of undissociated HL-A molecules and to be devoid of the cryptic HL-A common antigenic determinants that are found on HL-A 33,000-Dalton fragments obtained by dissociation with chemical reagents including acid. However, on exposure to acid, the antibody-dissociated 33,000-Dalton fragments were found to lose their HL-A alloantigenic and common antigenic characteristics and gain the cryptic HL-A common antigenic determinants. The greater part of the HL-A common antigenic determinants found here appears to be primate cross-reacting determinants.

Animals↗