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Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 1,387 records · Page 77Linked to original sources
PubMed1967

A comparison of some demand subject searches: machine vs. human.

A comparison of the results of machine and human information retrieval using MEDLARS and the printed Index Medicus indicates that at present neither method is entirely satisfactory for exhaustive literature searches. The advantages and disadvantages of machine and manual search methods are discussed, and solutions to some of the problems are suggested.

Information Services↗
PubMedDate not supplied

The combination of normal phase with reversed phase high performance liquid chromatography for the analysis of asparagine-linked neutral oligosaccharides labelled with p-aminobenzoic ethyl ester.

We have developed a novel approach for the analysis of asparagine-linked neutral oligosaccharides derived from glycoproteins. The oligosaccharides are labelled with p-aminobenzoic ethyl ester and the derivatives are separated on two high performance liquid chromatographic columns, one containing amide-silica and the other containing octadecyl-silica. The elution positions of 39 different ABEE-oligosaccharides on the two columns were plotted on a two-dimensional map. Unique non-overlapping positions of these oligosaccharides demonstrate that this technology would be useful for the identification of Asn-linked oligosaccharides at high sensitivity.

Asparagine↗
PubMedDate not supplied

Scanning electron microscopy of the liver cell cytoskeleton.

Rat livers were perfused with 0.5% Triton X-100 for 30 to 60 min and studied by scanning electron microscope. Three-dimensional filamentous networks were visualized in the cytoplasm of hepatocytes in situ. Branching and end-to-side contacts of intermediate filaments, and intermediate filaments which were connected with microtubules and microfilaments were noted. Numerous filaments were observed in the perinuclear region and at the cell border. Filaments were attached to polyribosomes and nuclei. No differences were observed in the cytoplasmic cytoskeleton after treatment of the sample at 4 degrees C. These results support the concept that intermediate filaments mechanically integrate the cytoplasmic space.

Animals↗
PubMedDate not supplied

Correlation between the biliary excretion of ouabain and the lateral mobility of hepatocyte plasma membrane proteins in the rat--the effects of age and spironolactone pretreatment.

The biliary excretion of intravenously injected ouabain and the diffusion constant of the lateral mobility of hepatocyte plasma membrane proteins were examined in control (saline-treated) and spironolactone-treated Wistar male rats of different ages (4, 14 to 15 and 24 months old). The biliary excretion of ouabain progressively decreased with age in control rats, the first 10-min biliary recovery in 24-month-old animals being one-third that of the youngest rats (4-month-old). The oral administration of spironolactone for 4 days (10 mg per 100 gm body weight on the first day and 20 mg per 100 gm body weight for the successive 3 days) caused a marked increase in the biliary recovery of ouabain in all age groups. Similarly, the average lateral diffusion constant of hepatocyte plasma membrane proteins as measured by fluorescence recovery after photobleaching showed a linear decrease with age, as was previously observed with F-344 rats of both sexes. Markedly and significantly (30 to 40%) higher diffusion constants were observed in rats pretreated with spironolactone for all three age groups, compared with the respective control values of corresponding ages. The parallelism between ouabain excretion and protein diffusion (i.e., a decrease with age and an increase with spironolactone pretreatment) suggests that the lateral mobility of proteins in the hepatocyte plasma membrane is a candidate mechanism for regulating ouabain excretion through the liver into the bile, most probably by regulating the hepatic uptake process for ouabain.

Aging↗