Stereological analysis of smooth endoplasmic reticulum and peroxisome proliferation in hepatocytes from neonatal and adult mice after phenobarbital administration.
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Biomedical subjects
Publications and source records attributed to K Kanai.
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The effect of T-2 toxin, a trichothecene compound, on bacterial infection was examined in mice infected intravenously with mycobacteria. T-2 toxin dissolved in olive oil was given orally in a dose of 0.1 mg, six to 12 times, at various stages of infection. The resistance-decreasing effect of the toxin was judged by two different criteria, the mouse survival period and the fate of tissue viable counts. This effect was accompanied by a decreased spleen weight. T-2 toxin was found to be a more potent immunosuppressing agent in this model than 5 mg of cortisone given intraperitoneally according to a similar schedule. In view of these observations, the potential importance of this mycotoxin was considered in relation to food hygiene.
The growth of rat ascites hepatoma cells (AH 66) in vitro was inhibited and the amount of alpha-fetoprotein (AFP) in the culture medium was increased in the presence of dibutyryl adenosine 3'-5' cyclic monophosphate (DBc-AMP). Electronmicroscopically, AH 66 cells that had been incubated with DBc-AMP showed an increase in polysomes on rough endoplasmic reticulum (RER), and some mitochondria appeared to be completely surrounded by RER. AFP in untreated cells was found to be localized on ribosomes of RER, free ribosomes and occasionally also on microvilli of cell membranes by electronmicroscopic and immunohistochemical analysis. After DBc-AMP treatment, increased staining of AFP was identified on ribosomes of RER and microvilli of cell membranes as well as on nuclear membranes. These results suggest that DBc-AMP accelerates the production and release of AFP in cultured rat ascites hepatoma cells.
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The smooth endoplasmic reticulum in hepatocytes of early postnatal and adult ddY male mice injected with phenobarbital was analyzed stereologically. The animals received daily intraperitoneal injections of phenobarbital and were killed about 24 h after the last injection. In early postnatal animals (injected with 35 mg/kg of the drug at days 1 and 2 after birth, or injected with 35 mg/kg at day 2 and with 50 mg/kg at days 3 and 4 after birth), the smooth endoplasmic reticulum proliferated both in perivenular and periportal hepatocytes; there was no significant difference in amount of smooth endoplasmic reticulum between the cells of the two zones. In adult animals, however, proliferation occurred only in perivenular cells after the administration of 35 mg/kg of phenobarbital for 2 days, and predominantly in perivenular cells even after the administration of 150 mg/kg of the drug for 7 days. These results suggest that the conspicuous proliferation of the smooth endoplasmic reticulum in perivenular hepatocytes in response to phenobarbital administration, which is characteristic of adult liver, does not occur in early postnatal mice but becomes manifest during postnatal development.
The volume and shape (the axial ratio:length/diameter) of mitochondria in periportal and perihepatic hepatocytes from newborn, 5 days old, 10 days old and adult male ddY mice were analysed by quantitative electron microscopy. In newborn animals, the volume and relative histogram of the axial ratio were not significantly different between periportal and perihepatic cells. Thereafter, the volume did not change significantly in periportal cells, whereas it decreased between 5 days of age and the adult in perihepatic cells. In adult animals, the volume in perihepatic cells was 26% of that in periportal cells. The relative histogram of the axial ratio for periportal cells deviated significantly to smaller values than in that for perihepatic cells in 5 days old, 10 days old and adult animals. Thus, the structural heterogeneity of hepatocyte mitochondria, evident in adult animals, is not present in newborn animals but arises during postnatal development.
Bacteriuria was screened among 28,202 healthy school children, 14,575 boys and 13,627 girls by dipstick and dipslide methods and also by pour plate culture method. Prevalence of bacteriuria was 0.06% in boys and 0.54% in girls after third screening. A high rate of false negative results with dipstick test and a high rate of false positive results with dipslide culture method using Microstix-3 were observed. About 60% of screened children continued to have bacteriuria persistently for 9 months after third screening followed by monthly urine culture. Anomalies of urinary tract were detected in 9 of 26 children with persistent bacteriuria.
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Glucose 6-phosphatase activity is higher in the principal cell than in other cell types in the terminal segment and caudal half of the middle segment of the mouse epididymis. Effect of castration and testosterone replacement on the high enzyme activity in the principal cell was studied in the terminal segment and the caudal half of the middle segment (cytochemical study), and in the whole epididymis (biochemical study). Ten, 20, or 30 days after castration, the abundant amount of reaction product seen in principal cells from intact control animals decreased to the level in basal cells, halo cells, and smooth muscle cells. However, in animals treated with testosterone following castration, the reaction product in principal cells remained abundant. Changes in the biochemical activity after castration or testosterone administration following castration paralleled the cytochemical results. Thus, the high activity in the principal cell is under the control of testosterone.
Distribution of alkaline phosphatase (ALPase) activity on the plasma membrane of rat hepatocytes in primary monolayer culture was observed using the backscattered electron image (BEI) mode. Apparent reaction product was seen in hepatocytes cultured for 48 or 72 hours in a concentration of 8 X 10(5) cells per ml, and those cultured for 72 or 96 hours in a concentration of 6 or 4 X 10(5) cells per ml. The reaction product was observed as scattered fine dots, as spots, and as bands along the cell edge, with high contrast in flattened polyhedral hepatocytes forming cell trabeculae. The deposition of the reaction product was generally more abundant at the periphery of the cell trabeculae. X-ray microanalysis revealed that the reaction product contains both lead and phosphorus as real ALPase reaction product. In transmission electron microscopy, the reaction product was exclusively localized on the external surface of the plasma membrane. However, the plasma membrane adjoining the culture substratum was devoid of the reaction product. Further, the highest biochemical ALPase activity appeared in earlier culture stages when the density of cultured cells was larger. Thus, during a few days of culture, ALPase activity increases on the plasma membrane predominantly at the periphery of the hepatocyte trabeculae. This increase in the activity might be related to the mechanism of preserving the cell shape.
Ultrastructural localization of glucose-6-phosphatase activity was studied in the cells of the pancreas and submandibular gland of the mouse using a incubation medium modified from that of Wachstein & Meisel (1956). In pancreatic acinar cells, the reaction product for the enzyme activity was not found even after 90 min of incubation with three changes of the medium. However, the reaction product was localized in the endoplasmic reticulum and nuclear envelope of all other cell types composing the pancreas and submandibular gland. The reaction product appeared in moderate to abundant amounts in acinar cells and striated duct cells of the submandibular gland, and in the B cells, A and D cells of the pancreatic islet, but it was scarce in other cell types.
An amino acid solution enriched in branched chain amino acids (BCAA) was administered to cirrhotic patients with encephalopathy and serial determinations of serum glucose, IRI and IRG were performed. Slight decrease of serum glucose was observed when only BCAA was given. On the other hand, when BCAA was infused with glucose, the serum glucose level decreased significantly after infusion (-77.5 +/- 26.2 mg/dl, p less than 0.01) and two cases of hypoglycemic shock were observed. Although both serum insulin and glucagon increased in these cases, the IRI/IRG molar ratio which was 8.9 at the start of infusion increased to 20.6 at the end of infusion. It was suggested that administration of BCAA with glucose caused hypoglycemia in cirrhotics with encephalopathy, possibly by synergistic action of BCAA and glucose on serum insulin level.
Localization of labeled material in hepatocytes of intact mouse liver injected via the portal vein with 125I-glucagon was studied. At 3 minutes after pulse injection of the labeled glucagon, most grains were localized associated with the plasma membrane. At 10 min after the injection, the grains were distributed throughout the cytoplasm and did not appear localized exclusively in any specific cell organelles. At 20 min after the injection, the labeled material appeared decreased, and was not yet localized exclusively in any specific cell organelles. Thus, in hepatocytes of intact liver, labeled glucagon is internalized more rapidly than in freshly isolated hepatocytes (Barazzone et al. 1980), and there appear to be no cell organelles in which internalized glucagon is preferentially localized.
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