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Biomedical subjects

K Kanai

Publications and source records attributed to K Kanai.

At least 163 records · Page 9Linked to original sources
PubMed1985

Quantitative analysis of development of mitochondrial ultrastructure in differentiating mouse hepatocytes during postnatal period.

Between birth and 10 days of age, the volume density (volume/unit cytoplasmic volume) of the matrix, and the surface density (area/unit cytoplasmic volume) of the inner membrane and cristae increased in both periportal and perihepatic hepatocytes, and did not differ significantly between the cells of the two zones. After 10 days of age, however, the volume density of the matrix decreased in perihepatic cells and remained unchanged in periportal cells, and, therefore, it became greater in periportal cells than in perihepatic cells in 20-day-old and adult animals. The surface density of the inner membrane and cristae decreased in the cells of both zones. Further, the hepatocyte volume increased markedly, especially in perihepatic zones between 20 days of age and the adult. The results show that, in postnatally differentiating hepatocytes, mitochondria are likely to develop during early postnatal period, then the structural heterogeneity of mitochondria arises, and hepatocyte volume increases markedly during late postnatal period after weaning. Thus, the process of postnatal hepatocyte differentiation includes such several phases of development.

Aging↗
PubMed1985

Prevention of perinatal transmission of hepatitis B virus (HBV) to children of e antigen-positive HBV carrier mothers by hepatitis B immune globulin and HBV vaccine.

The efficacy of hepatitis B immune globulin (HBIG) with two hepatitis B virus (HBV) vaccines was investigated for prevention of vertical transmission of HBV to infants born to e antigen-positive HBV carrier mothers. Infants received 150 mg of the F(ab')2 fraction of HBIG intravenously within 2 hr of delivery, and serum titers of antibody to hepatitis B surface antigen (anti-HBs) were kept greater than 1:4 (passive hemagglutination) by subcutaneous injection of HBIG thereafter. HBV vaccine was started three or six months after delivery. Of 50 infants older than nine months, 49 were actively immunized against hepatitis B surface antigen. Vaccine containing alum adjuvant immunized the infants in a shorter period than did vaccine without adjuvant. Serum titers of anti-HBs of actively immunized infants were well maintained afterward. None of the infants treated with HBIG and HBV vaccine was positive for serum antibody to hepatitis B core antigen at 12 months of age. No side effects were observed.

Adult↗
PubMed1985

Inhibitory effect of colchicine and vinblastine on transport of glucagon receptors to the plasma membrane in cultured rat hepatocytes.

The role of microtubules in the regulation of glucagon receptors on cultured rat hepatocytes was studied. Antimicrotubular reagents, colchicine and vinblastine, did not affect the binding of 125I-labelled glucagon to hepatocytes at 4 degrees C. At 20 and 37 degrees C, however, the reagents reduced the binding after 60 or 90 min of incubation. Scatchard analysis indicated that the reduction in the binding was due to loss of glucagon-receptor populations. If hepatocytes were preincubated with both unlabelled glucagon and the reagents at 37 degrees C, the binding of the ligand to the cells decreased markedly after a certain delay. The reagents did not inhibit the internalization of the ligand in the cells until 30 min of incubation at 37 degrees C. The results suggest that the microtubule system plays a role in the transport of glucagon receptors to the plasma membrane, which is followed by their internalization.

Animals↗
PubMed1985

Liposomes-mycobacteria incubation systems as a partial model of host-parasite interaction at cell membrane level.

The multilamellar lecithin-cholesterol liposomes entrapping carboxyfluorescence as a specific marker were prepared to be incubated with mycobacteria. The extent of resulting liposomal lysis was measured by marker release. Mycobacteria were highly active in this respect regardless of the species. Staphylococci were much less active and E. coli was completely inactive. Molecular species of lecithin and their ratio to cholesterol were related with the liposome sensitivity to mycobacteria. Ultrastructural and biochemical study showed that liposomes can be in close contact with mycobacteria and lecithins are degraded so that released fatty acids are incorporated into bacterial lipids, especially in virulent species. Liposomes-mycobacteria interaction was discussed as a partial model of the phagocyte-parasite interaction at the membrane level.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1985

Mechanism of bactericidal activity of lysolecithin and its biological implication.

Lysolecithin exhibited bactericidal effect on mycobacteria and staphylococci, but not on E. coli. The effect on staphylococci was manifested shortly after exposure, but that on mycobacteria was of the delayed type. The mycobactericidal activity was dependent on the fatty acid moiety of the chemical structure reflecting the cytotoxicity of the free form. The activity on staphylococci was not, however, of such fatty acid dependency and showed the same pattern of molecular species in hemolytic activity. These and other collateral findings suggest that the mycobactericidal effect of lysolecithin is due to the free fatty acids released therefrom by the enzymatic activity of the exposed bacterial cells, but that staphylococci are killed by the detergent effect of the whole lysolecithin molecule.

Escherichia coli↗
PubMed1985

A monoclonal antibody to a rat hepato-renal membrane antigen.

A monoclonal antibody against a membrane glycoprotein of rat hepatocytes has been produced. The nature of this antibody designated as HAM.4 was analysed by cellular radioimmunoassay, flow cytofluorography and indirect immunoperoxidase procedures. The following characteristics of HAM.4 were elucidated. First, an immunohistochemical study revealed that this antibody stained preferentially the bile canalicular face of hepatocyte membrane. Secondly, HAM.4 cross-reacted with kidney, spleen and thymus as well as liver. The kidney expressed much more the antigen molecules detected by this antibody than the liver did. The antigen was located predominantly on the brush border of proximal tubules in kidney. Thus, HAM.4 would be useful for analysing one of the brush border antigens of renal tubules which has been thought to be a pathogenic antigen for inducing experimental membranous glomerulonephritis. Finally, HAM.4 failed to label the cell membrane of rat hepatoma cell lines examined, indicating that the antigen detected by HAM.4 may disappear from cell surface during the course of hepatocarcinogenesis.

Animals↗
PubMed1984

Development of morphologic heterogeneity of hepatocyte mitochondria in the mouse.

The ultrastructure of mitochondria in periportal and perihepatic hepatocytes from newborn, 5-, 10-, and 20-day-old, and adult male ddY mice was analyzed by quantitative electron microscopy. In newborn and 5- and 10-day-old animals, the axial ratio (length per diameter), surface to volume ratio (area of the outer membrane per unit mitochondrial volume), and volume density were not significantly different between periportal and perihepatic cells. In 20-day-old and adult animals, the surface to volume ratio was greater in perihepatic cells than periportal cells, and the volume density was greater in periportal cells than perihepatic cells. The axial ratio became greater in perihepatic cells than periportal cells in adult animals. However, there were no differences in the surface density of the outer membrane, and of the inner membrane and cristae between the cells of both zones in all age groups examined. When the data were expressed as volume and area per cell, the patterns of subacinar distribution and age-related changes differed from the patterns seen in the volume and surface density data mainly in adult animals. This difference was generally caused by the marked increase in hepatocyte volume between 20 days of age and adulthood, especially in perihepatic cells. The results show that differences between mitochondria in periportal cells and those in perihepatic cells in the shape (the axial and surface to volume ratios), volume density, and area of the outer membrane per cell, evident in adult animals, are not present in newborn animals but arise during postnatal development.

Animals↗
PubMed1984

Receptor-mediated endocytosis of glucagon in isolated mouse hepatocytes.

The binding of glucagon to the cell surface and the pathway of intracellular transport of the hormone in isolated mouse hepatocytes were studied by autoradiography, colloidal gold-labeled glucagon (Au-glucagon), and biochemical methods. In cells incubated with 1251-glucagon at 4 degrees C, the label was mainly localized to the plasma membrane even after 60 min of incubation. At 20 degrees C, the labeled ligand was internalized by the cells and the amount of internalized ligand increased with time of incubation. At 37 degrees C, the ligand was rapidly internalized and found to be associated with coated or uncoated vesicles. Au-glucagon experiments revealed clearly the process of internalization of glucagon. Au-glucagon bound to the plasma membrane was transported to coated regions and then internalized into vesicles via coated pits. Biochemical results supported these findings from autoradiography and Au-glucagon experiments. Thus, glucagon is internalized by hepatocytes via receptor-mediated endocytosis.

Animals↗