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Biomedical subjects

H Kojima

Publications and source records attributed to H Kojima.

At least 595 records · Page 33Linked to original sources
PubMed1987

[A study on a functional difference in the mouse, rat and human I subregion products involved in the T cell proliferative responses to PPD].

A functional difference in the I subregion products involved in the T cell proliferative responses to PPD was studied using monoclonal antibodies, including HOK7, ISCR3 and 1B7, which detected class II antigens across the species barrier. HOK7 detected a polymorphic determinant on I-Ab molecules, D-2.7 (rat I-E equivalent) molecules and a monomorphic determinant on DR (human I-E equivalent) molecules. ISCR3 detected a monomorphic determinant on I-E molecules, D (rat I-E equivalent) molecules and DR (human I-E equivalent) molecules. 1B7 detected a polymorphic determinant on I-Ak molecules and a monomorphic determinant on B (rat I-A equivalent) molecules. It was demonstrated that the PPD specific proliferative responses of murine T cells were reduced by HOK7 or 1B7, while ISCR3 had no significant effects on these responses. In a rat system, however, the T cell proliferative responses to PPD were inhibited by HOK7 and ISCR3, but not by 1B7. Similarly, in a human system, the T cell proliferative responses to PPD were inhibited by HOK7 and ISCR3. These results indicate the interspecies difference in function of the I subregion products involved in the T cell proliferative responses. That is the restriction molecules in these responses of mice were mainly I-A molecules, whereas those of rats and humans were mainly I-E equivalent (D and DR) molecules.

Animals↗
PubMed1987

[Lymphocyte cytotoxicity against autologous tumor cells and the effect of interferon-beta on their activities. (1) Evaluation by modification of target tumor cells].

IFN is known to enhance NK activity against cultured cell lines such as K562, but not against frozen autologous tumor cells. In order to obtain increased NK cytotoxicity using IFN-beta, various modifications were performed on autologous tumor cells. IFN-beta induced more enhanced NK cytotoxicity of normal lymphocytes when frozen tumor target cells were cultured for 4-5 days in the medium, or when these cells were treated with Vibrio cholerae neuraminidase (VCN). However, in an autologous setting, IFN-beta did not enhance NK cytotoxicity against either cultured autologous tumor cells or VCN-treated tumor cells. Also, IFN-beta did not enhance cytotoxic T cell activity against autologous tumor cells induced by mixed lymphocyte-tumor cell culture, although IFN-beta was able to induce enhancement of allospecific cytotoxic T cells mediated by mixed lymphocyte culture.

Cells, Cultured↗
PubMed1987

[Regional cerebral blood flow in the acute stage with ischemic cerebrovascular disease studied by xenon-133 inhalation and single photon emission computerized tomography].

The papers about cerebral blood flow (CBF) in patients with cerebrovascular diseases have been already reported by positron emission computerized tomography (PET), single photon emission computerized tomography (SPECT), Xray CT (CT) using cold Xe, and so on. However the literature about the CBF changes in acute stage is few. We studied CBF in 68 patients with ischemic cerebrovascular disease within 48 hours after the onsets from February 1984 through February 1985. CBF was measured by a rapidly rotating single photon emission computerized tomography (SPECT) using non-invasive Xenon-133 inhalation method. Our subjects included 51 cases with cerebral infarction (male 37, female 14, average 62.9 years) and 17 cases with TIA (male 13, female 4, average 60.5 years), the patients who had a past history of stroke were excluded from the subjects. The SPECT was performed with use of Tomomatic 64 developed by Dr. Lassen, et al, SPECT and carotid arteriography were simultaneously performed within 48 hours in all cases. CT we used were GE CT 9800 scanner and Hitachi HF CT. The following results have been obtained: 1) SPECT clearly showed an ischemic focus correlated with clinical symptom after the attack rather than CT, the positive finding by SPECT was 92.2% and that by CT was 62.7% within 48 hours after the onset. 2) The remote effect phenomenon so-called crossed cerebellar diaschisis was demonstrated in 7 of 14 cases (50%) with cerebral infarction due to internal carotid artery occlusion and in 9 of 26 cases (34.6%) with that due to middle cerebral artery occlusion. 3) SPECT and CT were performed within 8 hours after the onset in 20 cases with cerebral infarction. SPECT showed decreased CBF in all cases whereas the positive finding by CT was 40.0%. The area of decreased CBF was always larger than the low density area that CT demonstrated. Mean CBF value of the cerebral hemisphere in the cases with ICA occlusion within 8 hours after the onsets was 31.0 (ml/100 g/min), and that of MCA occlusion was 36.0 (ml/100 g/min), and that of MCA occlusion was 36.0 (ml/100 g/min). 4) The positive finding by SPECT on TIA cases was 47% and that by CT was 41.1%, SPECT usually did not demonstrate a small ischemic focus especially at the deep region (ie, basal ganglia region). 5) SPECT using Xe-123 inhalation was useful and non-invasive method for the diagnosis in acute stage with ischemic cerebrovascular disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1986

A suppressive role of c-kinase for the stimulation of hepatic ketogenesis by glucagon and epinephrine.

The regulatory mechanism of hepatic palmitate oxidation into ketone bodies by c-kinase has been studied in isolated hepatocytes. Glucagon and epinephrine stimulated [U-14C]palmitate oxidation to ketone bodies by 60 and 25% as early as at 1 h. The stimulatory effects were almost totally prevented by the simultaneous presence of vasopressin, phorbol 12-tetradecanoate 13-acetate (TPA), or diacylglycerol (1-oleoyl-2-acetylglycerol). When hepatocytes were treated with glucagon or epinephrine, carnitine palmitoyltransferase (CPT), a key regulatory enzyme of palmitate oxidation, was activated. This hormone-induced activation of CPT was not observed in the presence of TPA. These observations suggest that c-kinase inhibits glucagon- or epinephrine-stimulated palmitate oxidation to ketone bodies, and that this inhibition may be mediated through a covalent modification of CPT.

Animals↗
PubMed1986

Mechanism of o-aminophenol metabolism in human erythrocytes.

o-Aminophenol was found to be rapidly metabolized to a brown compound in the presence of purified human oxy- and methemoglobin, coupled with the oxidation and reduction of these hemoglobins by o-aminophenol. The final product of o-aminophenol was identified as 2-aminophenoxazine-3-one, by using spectrophotometry and HPLC. The metabolism of o-aminophenol was also observed in human erythrocytes. The production rates of 2-aminophenoxazine-3-one in the cells were very fast, but these were strongly decreased by bubbling carbon monoxide into the cell suspension when intracellular hemoglobin was in the ferrous state. The production of 2-aminophenoxazine-3-one from o-aminophenol in the cells was completely suppressed by cyanide and azide when intracellular hemoglobin was in the ferric state. These results suggest that oxy- and methemoglobin are involved in metabolism of o-aminophenol to 2-aminophenoxazine-3-one in human erythrocytes.

Aminophenols↗
PubMed1986

A study on class II antigens involved in the T cell proliferative responses to PPD using cross-reacting monoclonal antibodies in human and murine system.

Two monoclonal antibodies (MoAb) 1E4 and ISCR3, which detect class II antigens across species barriers, were studied for their inhibitory effects on human and murine T cell proliferative responses to purified protein derivative of tuberculin (PPD). The 1E4 detected at least a polymorphic determinant on I-A molecules from mice carrying the H-2b haplotype, and the ISCR3 detected the Ia.7 determinant on I-E molecules. Nevertheless, both 1E4 and ISCR3 recognized monomorphic determinants on HLA-DR antigens (human I-E equivalent molecules), but not on HLA-DQ antigens (human I-A equivalent molecules). It was demonstrated that 1E4 significantly inhibited PPD-specific responses of T cells from Ib-bearing mice. In contrast, ISCR3 showed marginal effects on the responses of mice bearing Ia.7. However, in the human system both 1E4 and ISCR3 reduced proliferative responses to PPD. These results suggest that a functional difference exists between humans and mice in the I subregion products involved in the T cell proliferative responses to PPD.

Animals↗
PubMed1986

A monoclonal antibody (1B7) specific for polymorphic determinant on mouse I-A antigens recognizes monomorphic epitope shared by most of RT-1 haplotypes in rats.

A monoclonal antibody, 1B7, which was established by immunizing C57BL/10 mice with splenocytes from B10.BR, was investigated by serological, immunochemical and functional analyses in mouse, rat, guinea pig and human systems. 1B7 recognized a polymorphic determinant on class II antigens in the mouse system. In the rat system, however, this antibody appeared to recognize a monomorphic epitope shared by all RT-1 haplotypes. 1B7 showed no reactivity in the human and guinea pig strains tested.

Animals↗