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Biomedical subjects

T Matsui

Publications and source records attributed to T Matsui.

At least 1,099 records · Page 61Linked to original sources
PubMed1978

[The fine structure of cell processes in astrocytoma (author's transl)].

Astrocytes, in normal tissue, may be characterized by their extensive processes which may be cylindrical in part but are sheet-like at their periphery where they serve to cover other structures. It becomes of interest ot determine the morphology of astrocytic processes after neoplastic transformation. We, therefore, examined the fine structure of 14 cases of astrocytomas. In general the fine structure of the cell bodies and the interior of the processes are fundamentally similar to those of normal or developing astrocytes. Differences are apparent at the cell periphery. These include less well developed cell junctions and usually only poorly formed peripheral expansions of the processes. Most sections through the processes appear round or oval rather than laminar in normal astrocytes. They often consist of small microvilli or pseudopodia-like protrusions. Whether these changes are due to the immaturity of the cell or to the lack of appropriate nearby target cells is not known.

Astrocytes↗
PubMed1977

Experiences with the tracheoesophageal shunt method for vocal rehabilitation after total laryngectomy.

The tracheoesophageal (T-E) shunt technique reported by Komorn et al. (1973) was used for vocal rehabilitation in 8 laryngectomized patients including one case of hypopharyngeal cancer. It was proved that this technique was a simple one-stage procedure with a low incidence of complication. Four out of 7 patients, excluding one patient who died of another disease, acquired excellent speech without symptomatic aspiration. Two patients developed fairly good speech. One shunt was closed by aspiration. The shunt constructed by a flap measuring 2 x 4 cm, opened 1 cm below the distal end of the trachea, showed good results. The T-E shunt speech exceeds esophageal speech in duration and intelligibility.

Esophagus↗
PubMed1977

Liver protocollagen proline hydroxylase in human liver diseases and experimental liver fibrosis.

Liver protocallagen proline hydroxylase activity (PPH activity) was determined in patients with various liver diseases, CCl4-induced liver fibrosis rats and cholin deficiency (tcd) fatty liver rats. The following results were obtained: Liver PPH activity in patients with chronic hepatitis was higher than that in patients with acute hepatitis, while the activity in patients with liver cirrhosis was much higher than that in patients with chronic hepatitis. The activity was higher in patients with chronic active hepatitis than in those with chronic inactive hepatitis. Patients with active and progressive liver cirrhosis were found to have an especially high PPH activity, in whom the activity reflected well the degree of liver fibrosis. Even though fibrosis in persistent hepatitis was almost negligible or slight, the degree of liver PPH activity in persistent hepatitis was similar to that in liver cirrhosis. Liver PPH activities in CCl4-induced liver fibrosis rats and CD fatty liver rats elevated proportionally to the lapse of time. Whilst liver PPH activity in rats of CD fatty liver without fibrosis in 23 to 31 weeks after the start of the experiment was slightly lower than that in rats of CD fatty liver with fibrosis. But liver PPH activity of the former was considerably higher than that of control rats.

Acute Disease↗
PubMed1976

Nucleolar DNA-dependent RNA polymerase from rat liver. 1. Purification and subunit structure.

DNA-dependent RNA polymerase I (or A) was purified from rat liver nucleoli. DNA was effectively removed from the solubilized enzyme with a defined concentration of polyethyleneglycol. The enzyme was purified further with successive DEAE-Sephadex and phosphocellulose column chromatography followed by glycerol gradient centrifugation. The procedure yielded an electrophoretically homogeneous enzyme with a specific activity 400 times that of the nucleolar extracts. The recovery of the activity was approximately 20%. The RNA polymerase I eluted as a single peak from DEAE-Sephadex was separated into two distinct peaks by a phosphocellulose column. The first peak eluting at about 0.12 M ammonium sulfate was designated as RNA polymerase IA and the second peak eluting at about 0.18 M as RNA polymerase IB. In normal rat liver nucleoli IA enzyme comprised approximately 20% of the total RNA polymerase I activity and the IB enzyme comprised approximately 80%. On sodium dodecyl sulfate polyacrylamide gel electrophoresis, enzyme IB contained five subunits with molecular weights of 195000 (a), 130000 (b), 65000 (c), 40000 (d), and 19000 (e) at nearly equimolar amounts. The calculated molecular weight of the enzyme (449000) agreed well with that predicted from the sedimentation coefficient of the enzyme. Enzyme IA contained identical subunits except that subunit c was absent. Preliminary studies could not demonstrate any significant differences in template specificity between IA and IB enzyme.

Animals↗
PubMed1976

Nucleolar DNA-dependent RNA polymerase from rat liver. 2. Two forms and their physiological significance.

RNA polymerase I (or A) was extracted from nuclear, nucleolar and nucleoplasmic fractions, and resolved into IA and IB forms on a phosphocellulose column. During the course of cycloheximide treatment, the activity of RNA polymerase IB decreased in the nucleoli with concomitant increase in the nucleoplasmic fraction, suggesting strongly that cycloheximide induced specific leakage of IB enzyme from the nucleolus. The activity of IA enzyme did not change in the nucleoli. When nucleoli were incubated in the presence of actinomycin D, all the IA enzyme activity and approximately 30% of the total IB enzyme activity were released in the incubation medium, whereaa 70% of IB activity remained associated with the nucleolar pellet where no IA activity was detected. The enzyme which was released into the incubation medium was tentatively designated as free or unbound RNA polymerase I and that which was associated with the nucleolar pellet as template-bound enzyme. During the treatment with cycloheximide, the activity of bound enzyme, which contained exclusively IB form, decreased rapidly, with kinetics almost identical to that of nucleolar RNA synthesis in vivo. The activity of free enzyme did not change appreciably. At 2 h after partial hepatectomy, IB enzyme activity in the free RNA polymerase fraction increased to almost twice the control, while the bound enzyme activity did not increase appreciably until 4h of regeneration. Enhancement of nucleolar RNA synthesis in vivo was not apparent at 2 h but became significant by 4 h after partial hepatectomy. These results strongly suggest that (a) the above-mentioned procedure is actually fractionating RNA polymerase I into free and bound forms, (b) RNA polymerase IB is the transcriptionally active form in vivo, (c) RNA polymerase IB exists in excess in the nucleoli, but the amount of bound IB molecules, which are engaged in transcription in vivo, must be determined by some other factor(s) than the mere concentration of IB enzyme in the nucleolus, and (d) IA form is not an artifact of isolation but is always present in vivo at a certain amount, although the exact nature of this molecule is not known at present.

Animals↗