Search PubMed⌕ Search

Biomedical subjects

K Isobe

Publications and source records attributed to K Isobe.

At least 343 records · Page 19Linked to original sources
PubMed1982

The donor cell type controls anti-hapten (fluorescein isothiocyanate) primary antibody response to hapten-modified syngeneic cells.

Hapten (fluorescein isothiocyanate, FITC)-sensitized syngeneic red blood cells (FITC-RBC) are exceptionally active for induction of anti-hapten primary antibody response, and FITC-modified syngeneic spleen cells depleted of RBC (FITC-SSC) are not immunogenic [4]. The present study has demonstrated that FITC-SSC injected simultaneously with FITC-RBC inhibit partially the anti-FITC response to the latter. Either the immunogenicity of FITC-RBC or the response-inhibiting activity of FITC-SSC was increased as the concentration of hapten-sensitizing cells was raised from 0.005 mg/ml to 2 mg/ml. The inhibition of anti-FITC response by FITC-SSC strictly required live donor cells, but was not dependent on T-cell activity of either the donor or recipient. Neither FITC-thymocytes nor the FITC-T-cell-rich fraction of SSC showed a definite activity for inhibition, whereas the FITC-B-cell-rich fraction of SSC acted very effectively. These results suggest that the primary anti-hapten antibody response to hapten-modified syngeneic cells is primarily controlled by antigen-bearing live donor cells of different cell types.

Animals↗
PubMed1982

Further studies of the polysaccharide of Klebsiella pneumoniae possessing strong adjuvanticity. III. Augmentation of the antibody response to subcutaneously injected sheep red blood cells by the adjuvant polysaccharide.

The adjuvant action of the O3 antigen of Klebsiella (KO3) on the antibody response to sheep red blood cells (SRBC) was elucidated by injecting both KO3 and SRBC subcutaneously at the right inguinal region of SMA mice. We demonstrated that KO3 exhibits a novel ability to augment anti-SRBC plaque-forming cell responses in both the local lymph node and the spleen at a relatively late stage of immunization. Escherichia coli lipopolysaccharide, dextran sulfate and concanavalin A showed such an action only minimally. In parallel with the development of the adjuvant action, KO3 definitely activated B cells in the local lymph node polyclonally for either IgM or IgG synthesis, suggesting that the mechanism of the adjuvant action includes direct stimulation of B cells by KO3 at the late stage. Neither increase in trapping of lymphocytes in the local lymph node nor change in tissue distribution of antigen was shown to be primarily involved in the mechanism of the adjuvant action.

Adjuvants, Immunologic↗
PubMed1982

Mechanism of development of bronze baby syndrome in neonates treated with phototherapy.

Comparisons of serum concentrations of unknown pigment and photobilirubin IX alpha , the two main bilirubin photoproducts, were made during phototherapy in infants with and without bronze baby syndrome who were treated similarly. The serum concentrations of unknown pigment estimated by high-pressure liquid chromatography in infants with the bronze baby syndrome were significantly increased in comparison with those in the control hyperbilirubinemic neonates during phototherapy. However, there was no difference in the serum concentrations of photobilirubin IX alpha between infants with bronze baby syndrome and the control groups. The unknown pigment separated from bilirubin photoproducts obtained from experiments in vitro by high-pressure liquid chromatography was gradually decomposed into brown products that showed the absorption spectrum similar to that of the serum of infants with bronze baby syndrome. This fact is probably due to reduction in hepatic excretory function of bilirubin photoproducts, especially in known pigment, because its main excretory pathway is the biliary route. The pigment accumulated in the body may be polymerized and forms bilifuscin-like substances following a free radical reaction. It is concluded that the brown pigment is formed via unknown pigment.

Bilirubin↗
PubMed1981

Kinetics of biliary excretion of the main two bilirubin photoproducts after injection into Gunn rats.

The kinetics of biliary excretion of the main two photoproducts after injection into Gunn rats were examined. The photoproducts that are obtained from experiments in vitro consist of unknown pigment, photobilirubin IXa and a small amount of (ZZ)-bilirubin IXa. It was confirmed previously that the first two photoproducts are identical with the main two photoproducts obtained in vivo. In experiments on four animals, the average of total biliary recoveries of unknown pigment was 81.4%, and that of photobilirubin IXa in the bile estimated by the Sigma-minus method was 29.8 min and that for unknown pigment was 4.3 min. The rate of thermal reversion of photobilirubin IXa to (ZZ)-bilirubin IXa in the bile at 37 degrees C was very rapid, i.e. its half-life was 6.2 min.

Animals↗
PubMed1981

Cytochemical demonstration of transferrin in the mitochondria of immature human erythroid cells.

The direct immunoperoxidase technique was employed to show the localization of transferrin in immature human erythroid cells. The present method is interesting in that use was made of a small marker (HRP-Fab' complex) and in that the endogenous peroxidase was blocked under a controlled condition- this ensured good structural preservation allowing electron-microscopic examination. Cytoplasmic transferrin was found not only in the micropinocytotic vesicles but also within the mitochondrial membrane. Similar findings were made in all the immature erythroid cells examined, each of which was in a different erythropoietic condition. Thus, it may be concluded that the present study provides morphological evidence for the endocytotic iron transport to the mitochondria.

Endocytosis↗
PubMed1981

A significant role of proximity of HVJ-antigen in the generation of tumor immunity.

According to the blocking test for proximity of cell surface antigens, L1210 leukemia-associated antigen was not linked to molecules carrying H-2d antigen or murine leukemia virus-associated antigen, but there was a close association between HVJ-associated antigen and L1210 leukemia-associated antigen on the surface membrane of HVJ-pi-infected L1210 leukemia cells. Once L1210 leukemia cells were infected with HVJ-pi, their adsorptive power was found to be greater than that of uninfected cells by quantitative absorption analysis. These phenomena may lead to a better recognition by the host of L1210 leukemia-associated antigen, followed by generation of tumor immunity.

Absorption↗
PubMed1981

Induction of tumor resistance by hybrid cell lines between human acute lymphocytic leukemia cells and mouse myeloma cells.

Three hybrid cell lines were derived from the fusion of BALB/c mouse NS-1 myeloma cells and human acute lymphocytic leukemia cells. Hybrid clones contained almost all of the mouse chromosomes and a few human chromosomes, and induced tumors in BALB/c and BALB/c nu/nu mice when inoculated subcutaneously. However, the tumors of BALB/c mice subsided spontaneously within one month. The mice which survived the inoculation of 5 approximately 10 X 10(6) hybrid cells were able to reject a subsequent challenge with 5 X 10(6) NS-1 cells. Spleen cells or lymph node cells from immune mice were injected into BALB/c mice. These mice lived longer than the mice which received normal spleen cells or normal lymph node cells, when challenged with 5 X 10(6) NS-1 cells. These results suggest that a rearrangement of tumor-specific antigens on human/mouse hybrid cells can induce immunogenicity.

Animals↗
PubMed1980

High-pressure liquid chromatographic analysis of anaerobic photoproducts of bilirubin-IX alpha in vitro and its comparison with photoproducts in vivo.

To carry out photochemical experiments under conditions similar to those prevailing for neonatal bilirubin metabolism in jaundice phototherapy, we have studied photoproducts produced by the action of light on a bilirubin--albumin solution and further clarified the relationship between the photoproducts obtained from experiments in vitro and in vivo. (1) An accurate and sensitive separation method by high-pressure liquid chromatography for photoproducts of bilirubin under anaerobic irradiation of visible light is described. (2) There were two main photoproducts obtained from experiments both in vivo and in vitro. (3) Exact correspondence of retention time on high-pressure liquid chromatography, diazo-reactivity, thermal reversion and absorption-spectrum maxima was observed between unknown pigment and photobilirubin-IX alpha from biological fluids, and the comparable peaks 2 and 3 from experiments in vitro. (4) The behaviour of photoproducts in various solutions in the absence of light and O2 is described. (5) A lower affinity of photoproducts, especially unknown pigment, for human serum albumin than with bilirubin-IX alpha for the albumin was demonstrated by the gel-filtration method.

Anaerobiosis↗
PubMed1980

Demonstration of a geometric isomer of bilirubin-IX alpha in the serum of a hyperbilirubinaemic newborn infant and the mechanism of jaundice phototherapy.

Photobilirubin-IX alpha in the serum of a hyperbilirubinaemic newborn infant was demonstrated for the first time by reversed-phase high-pressure liquid chromatography. The concentrations increased significantly during phototherapy. Corresponding to these changes in the serum, biliary unconjugated bilirubin concentrations increased markedly but photobilirubin-IX alpha was not detected in the bile. Moreover, large amounts of 'unknown pigment' that are diazo-negative appeared in the bile during phototherapy.

Bile↗
PubMed1980

An accurate and sensitive analysis by high-pressure liquid chromatography of conjugated and unconjugated bilirubin IX-alpha in various biological fluids.

An accurate and sensitive method was developed for the complete separation of the native tetrapyrroles, such as bilirubin and its mono- and di-conjugates of glucuronic acid, glucose and xylose, by ion-pair reversed-phase high-pressure liquid chromatography. The application of this method was demonstrated by the analysis of bile pigments in human bile and urine, and the method also makes it possible to estimate very low UDP-glucuronyltransferase activity, such as is found in the human foetal and neonatal liver.

Adult↗