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Biomedical subjects

M Oda

Publications and source records attributed to M Oda.

At least 613 records · Page 34Linked to original sources
PubMed1977

Bile canalicular membrane pathology in cytochalasin B-induced cholestasis.

The mechanism of cytochalasin B-induced intrahepatic cholestasis was examined using electron cytochemical techniques. Since previous studies suggested that the earliest lesions were in hepatic canaliculi, markers were used for three canalicular membrane components, namely ruthenium red for the glycoprotein-rich surface coat, the Mg2+-ATPase reaction as an example of a membrane-bound protein, and uranyl acetate en bloc and ruthenium red staining for the canalicular membrane-associated microfilaments. In rat liver infused in vivo with cytochalasin B, reduction in bile flow correlated with bile canalicular dilation, loss of the ruthenium red-positive surface coat from the canalicular membrane, and loss of demonstrable Mg2+-ATPase activity. In addition, structural alterations in microfilaments with widening of the ectoplasmic zone were noted. In isolated liver cells in vitro, identical changes were found. Bile canaliculi isolated from the in vivo cytochalasin B-infused rat liver lacked their normal investment of microfilaments. Detachment of the filaments from the bile canalicular membrane may be involved in the mechanism of cytochalasin B-induced cholestasis.

Adenosine Triphosphatases↗
PubMed1977

Anti-HBc titer in relation to the etiological role of hepatitis B virus in primary hepatocellular carcinoma.

The antibody to hepatitis B core antigen (anti-HBc) is belived to be a marker for natural infection with hepatitis B virus (HBV). In order to study the etiological role of HBV in relation to primary hepatocellular carcinoma (PHC), the anti-HBc in sera of 31 PHC patients was surveyed by the immune adherence hemagglutination method which was about 10 times more sensitive than the complement fixation method. Twenty two out of 31 PHC cases were positive for anti-HBc (71.0%). The is a higher rate of incidence than that of HBs-Ag (51.6%). However, high anti-HBc titer above 2(10) which might reflect current infection with HBV was observed in 15 of these 22 cases. The remaining 7 cases had a titer lower than 2(8); 5 of these patients had neither HBs-Ag nor anti-HBs in their sera. As control, 37 anti-HBs positive blood donors with no definite liver disease were surveyed for anti-HBc titer. Thirty-four of them were positive, but in the majority of cases, the serum titer was less than 2(9), which might only reflect previous infection with HBV. These findings indicate that not only the prevalence of anti-HBc, but also the determination of its real titer is quite important for studying the relationship of HBV to PHC.

Carcinoma, Hepatocellular↗
PubMed1975

[An autopsy case of olivocerebellar and thalamic degeneration, diffuse sclerosis and hypertrophic neuropathy: infantile system degeneration? (author's transl)].

The brain of a 21-year-old man with imbecility and spastic tetraplegia since early childhood showed a diffuse sclerosis of the cerebral white matter and symmetrical degeneration of the thalamus and olivocerebellar system. The spinal nerve roots as well as proximal branches of the spinal nerves were hypertrophic and there was seen a marked fibrosis with some onion-bulb formations of Schwann cells. In spite of a possible relation to an unknown infection at the age of 3 months this case could preferably be regarded as a peculiar form of the combined system degeneration in the early childhood, including the cerebral white matter and peripheral nerves. An uncle of the patient had died of a similar nervous disease at the age of 20 years.

Adult↗
PubMed1975

Characterization of rat liver cell plasma membranes.

A method is described by which bile canalicular membranes (BCM) can be prepared, together with canaliculus-free plasma membrane (PM), both essentially free of contamination. The recovery of both fractions together was estimated to be 46%. The concentrations of total lipid, total phospholipid and cholesterol were substantially greater in the BCM, and polyacrylamide gel electrophoresis revealed differences in protein composition. The differences in lipid and protein composition of these two plasma membrane fractions are presumably related to their very different physiological functions.

Animals↗
PubMed1975

Microfilament dysfunction as a possible cause of intrahepatic cholestasis.

The effects of cytochalasin B on bile canalicular structure and function were examined. Three experimental models were used, cultured hepatocytes, isolated perfused liver, and in vivo infused liver. The techniques used were light and electron microscopy and, in selected instances, scanning electron microscopy, electron "stains" for microfilaments, and measurements of bile flow. Microfilament disruption and dilation of bile canaliculi were consistently found and closely paralleled a reduction in bile flow in both in vitro and in vivo infused animals. It is proposed that under normal circumstances, the microfilaments maintain the canaliculi in a contracted or partly contracted state. Hence, the microfilamentous network would provide tone to the canalicular system which would tend to reduce stagnation and facilitate the flow of bile. Removal of normal microfilament contractile function would be expected to produce canalicular ectasia and reduction of bile flow, as was observed. Microfilament dysfunction may therefore be a possible cause of intrahepatic cholestasis. Crucial to this hypothesis are the presence of actin-containing microfilaments in the pericanalicular web, and an action of cytochalasin B on their contractility. Evidence pertaining to these requirements is presented and discused.

Animals↗
PubMed1975

Electron microscopic cytochemical characterization of bile canaliculi and bile ducts in vitro.

Electron microscopic cytochemical localization of Mg++-activated adenosine triphosphatase (Mg++-ATPase) and 5-nucleotidase (AMPase) was investigated in bile canaliculus-rich and bile duct-containing fractions isolated from rat liver. Comparative cyochemical studies between prefixed and non-prefixed fractions revealed that the activity of both enzymes could be detected in the fractions under appropriate experimental conditions. However, the cytochemical activity of AMPase was much more sensitive to glutaraldehyde than that of Mg++-ATPase. Mg++-ATPase and AMPase reaction products were localized primarily on bile canalicular microvilli, that is, along the outer (luminal) surface of canalicular plasma membranes, but they were never observed on bile ductal microvilli. AMPase was also detectable on lateral hepatic plasma membranes. Mg++-ATPase demonstrated by the cytochemical technique described is a reliable enzyme marker for isolated bile canalicular membranes. At high magnification, Mg++-ATPase reaction product was also observed on the microfilaments surrounding isolated bile canaliculi. The possibility that the reaction product on the pericanalicular microfilaments may result from the hydrolysis of ATP byan actomyosin ATPase-like enzyme associated with these filaments is briefly discussed.

Adenosine Triphosphatases↗