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Biomedical subjects

I Nakamura

Publications and source records attributed to I Nakamura.

At least 325 records · Page 18Linked to original sources
PubMed1983

A study of the sex ratio of first-born according to the mother's month of birth.

The male-to-female sex ratio at birth of the first-born babies delivered in Japan to mothers aged 25 years or less was investigated in two groups: a hospital group and a questionnaire group. The sex ratio fluctuated according to their mother's month of birth. Between 1924 and 1928, the sex ratio of the offspring of the mothers born in March-May in both groups was significantly higher than that of the other mothers. We speculate about the relationship between the sex ratio at birth and the mother's month of birth.

Adult↗
PubMed1983

Tachistoscopic recognition of normal and mirror images of Kana and Kanji characters.

Accuracy of recognition was investigated for normal and mirror images of Kana (syllabic symbols) and Kanji (ideographic symbols) characters tachistoscopically presented in the left and right visual fields in normal right-handed Japanese subjects. A significant right field superiority was obtained for the recognition of each type of normal letter. In the case of mirrored letters, Kanji characters were better recognized in the right field while no lateral asymmetry for the recognition of Kana characters was shown. The results indicated that Kanji processing is somewhat different from the processing of Kana characters.

Adult↗
PubMed1983

[Studies on the cell-mediated immunity caused by beryllium compounds].

In order to examine the sensitizing ability of beryllium (Be), a footpad reaction test and a macrophage migration inhibition test were carried out using mice treated with beryllium compounds. The findings of the experiments are summarized as follows: 1) The footpad reaction test of the mice injected with BeCl2 once a week subcutaneously at their dorsal area showed the positive results after four injections. The macrophage migration inhibition test was also performed by an agarose plate method using peritoneal cells and spleen cells obtained from these mice. The ratio of the number of positive mice showed more than 50% after five injections when peritoneal cells were used and after six injections when spleen cells were used. 2) The footpad reaction test of mice injected with one of various Be-compounds six times once a week showed a cross positive reaction against these compounds, and the macrophage migration of these mice was inhibited by these Be-compounds, but not by other metals. 3) When mice were once injected with 7BeCl2, about a half dose of the injected metal was discharged from the body within 7 days after the injection, and about a half dose of the residual metal was still found in the injected site. Further investigations may be required to solve the point that the persistent remaining of this metal in situ may raise the Be sensitizing ability.

Animals↗
PubMed1983

Target determinants for F1 hybrid anti-parental H-2d cell-mediated lympholysis: self antigens controlled by the D end.

The immunogenetic specificity and reactivity with syngeneic target cells were determined for (C57BL/6 x DBA/2)F1 anti-parental DBA/2 cytotoxic T lymphocytes (CTL) elicited in primary mixed spleen cell cultures. A panel of peritoneal exudate cells (PEC) from mice bearing nonrecombinant and recombinant H-2-Tla haplotypes and their F1 hybrids was used as the source of target and inhibitor cells for direct lytic and competitive inhibition assays. PEC of H-2d and several recombinant haplotypes bearing the d alleles at the D region, including H-2u, were as susceptible to lysis as parental DBA/2 PEC, irrespective of non-N-2 genetic constitution. Those of H-2b, H-2k, H-2s, and recombinant haplotypes not carrying the d allele in the D region were not lysed above the background levels. Syngeneic F1 PEC were not lysed by CTL, but were nevertheless capable of inhibiting the lysis of DBA/2 PEC, albeit slightly less effectively than homozygous Dd-positive PEC inhibitors. Mapping by inhibition assays indicated that the presence of at least one copy of the H-2Dd allele was necessary and was sufficient to confer inhibitory capacity to H-2 heterozygous PEC. These results extend previous observations on primary F1 anti-parental H-2b and H-2k cell-mediated lympholysis (CML) and indicate generality of autoreactive F1 anti-parent CML responses against surface structures coded for or controlled by H-2K or H-2D region genes.

Animals↗
PubMed1983

Role of suppressor cells in the decline of natural killer cell activity in estrogen-treated mice.

Previous studies have shown that prolonged estrogen treatment of mice markedly reduces their natural killer (NK) cell activity. Our experiments demonstrate that splenocytes from (C57BL/6 X C3H/He) F1 mice treated with 17 beta-estradiol are suppressive for the NK activity of splenocytes from untreated mice when the two cell populations are mixed during cytotoxicity assays. The suppressor activity is resistant to treatment with anti-Thy-1.2 or anti-la reagent plus complement, can be generated in neonatally thymectomized mice, and is present in plastic-adherent as well as nonadherent cell populations. Treatment with a NK-reactive antiserum, either anti-asialo-GM-1 or anti-NK-1.2, has no effect on the suppressor activity. Administration of the interferon inducer polyinosinic-polycytidylic acid to mice treated with estrogen results in moderate restoration of NK activity but has no effect on the suppressor activity. These data suggest that generation of a Thy-1-negative/la-negative suppressor cell population is, at least in part, responsible for the reduced levels of NK activity in estrogen-treated mice.

Animals↗
PubMed1983

Selective defect of natural killer and killer cell activity against lymphomas in SJL mice: low responsiveness to interferon inducers.

Three unrelated inbred strains of H-2s mice, SJL/JN, A.SW, and B10.S, were classified according to the levels of splenic NK activity against susceptible lymphoma targets, with or without prior administration of the interferon (IFN) inducer p-I:C to the prospective donors of splenocytes: 1) SJL/JN had low endogenous activity that responded poorly to p-I:C-induced augmentation; 2) A.SW exhibited low levels of spontaneous activity that were inducible to higher levels by p-I:C; and 3) B10.S showed high endogenous levels of activity that were augmented to a still higher level by p-I:C treatment. In vitro incubation of spleen cells with partially purified IFN-beta for up to 12 hr augmented NK activity of A.SW and B10.S but not of SJL mice. The relative levels of K cell-mediated ADCC in the three strains were similar to those of NK activity, including augmentability by p-I:C; however, the capacity to perform three additional cell-mediated immune functions, i.e., natural cytotoxicity against a fibrosarcoma target, adherent cell-mediated ADCC against antibody-coated chicken RBC, and alloimmune T cell-mediated cytotoxicity against appropriate targets, did not distinguish one strain from another. The low NK phenotype in SJL/JN remained distinctive throughout postnatal life, but there was a tendency for the highest levels of NK activity to occur in 4 to 8-wk-old mice.

Animals↗
PubMed1982

[Effects of aromatic nitro and amino compounds on the osmotic fragility of red cells].

Using the Coil Planet Centrifuge system, effects of single and repeated subcutaneous injections of p-nitrochlorobenzene [PNCB], aniline [AN] and phenylhydrazine [PH] on the osmotic fragility of red cell membrane in rabbits were studied. Methemoglobin [MHb] levels and appearance of Heinz bodies were also determined. In the single injection experiment, the osmotic fragility was increased immediately after the subcutaneous injections of PNCB [50 mg/kg, 100 mg/kg and 200 mg/kg], AN [50 mg/kg, 250 mg/kg and 500 mg/kg] and PH [25 mg/kg and 45 mg/kg]. The increased MHb levels were observed first, and secondly the maximum changes of the osmotic fragility and appearance of Heinz bodies were observed nearly simultaneouly after the injections of these three compounds. In the repeated injection experiment, hemolysis starting point was shifted toward higher osmotic pressure immediately after the injections of PNCB [5 mg/kg/day and 10 mg/kg/day], AN [20 mg/kg/day and 30 mg/kg/day] and PH [1 mg/kg/day and 3 mg/kg/day], while it was shifted toward lower osmotic pressure after the last doses of PNCB and PH. Hemolysis ending point was shifted toward higher osmotic pressure after the injections of PNCB [10 mg/kg/day] and AN, while it was shifted toward lower osmotic pressure after the injections of PNCB [5 mg/kg/day] and PH. The injection of PNCB induced continuously the increased MHb levels and appearance of Heinz bodies. The injection of PH induced the continuous appearance of Heinz bodies and the transiently increased MHb levels. Although the injection of AN induced the transiently increased MHb levels, there were no appearance of Heinz bodies. These findings show that the early and continuous changes in red cell membrane induced by these three compounds were able to be detected by the use of the Coil Planet Centrifuge system. The changes in red cell membrane induced by single and repeated injections of PH were able to be detected even when the increased MHb levels were not detected. Furthermore, the changes induced by the repeated injection of AN were able to be detected even when the increased MHb levels and the appearance of Heinz bodies were not detected. Thus, it seems likely that the Coil Planet Centrifuge method is useful to examine workers exposed to aromatic nitro and amino compounds.

Aniline Compounds↗
PubMed1982

Acute effect of cigarette smoking on serum angiotensin-converting enzyme activity in normal man.

The acute effect of cigarette smoking on serum angiotensin-converting enzyme activity was evaluated in 6 healthy subjects consisting of 4 non-smokers and 2 habitual smokers. Cigarette smoking resulted in rapid increases in serum converting enzyme activity in 5 of 6 subjects within 5 min. and the converting enzyme activity remained above the control value at 30 min. The increase in the enzyme activity of non-smokers was higher than that of habitual smokers at any time when the enzyme activity was determined. It is therefore suggested that cigarette smoke (or smoking) can cause the secretion of angiotensin-converting enzyme from the pulmonary endothelial cell, in which the enzyme may be produced, to the systemic circulation. It is also speculated that the increase in the enzyme activity may contribute to the initiation of cardiovascular changes associated with cigarette smoking.

Adult↗