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Biomedical subjects

G Takahashi

Publications and source records attributed to G Takahashi.

At least 19 recordsLinked to original sources
PubMed1992

Rough endoplasmic reticulum in the adrenaline and noradrenaline cells of the adrenal medulla: effects of intracranial surgery and pinealectomy.

UNLABELLED: Adrenal medullas in 53-day-old rats of the nonoperated (NO) group (n = 31), the sham-operated (SPX) group (n = 35) and the pinealectomized (PX) group (n = 38) were examined electron microscopically 14 days after surgery. Cell profiles showing solitarily and sparsely distributed rough endoplasmic reticulum (RER) were most frequent in the PX group (daily mean: 66.9%, 427/638), less in the NO (56.0%, 336/600), and least in the SPX (48.5%, 297/612) in adrenaline (A) cells (chi 2-test: P less than 0.001), while most frequent in the NO group (68.8%, 340/494), less in the PX (64.3%, 303/471), and least in the SPX (57.4%, 256/446) (P less than 0.005) in noradrenaline (N) cells. Individual variation was less in A cells than in N cells. Cell profiles showing a large accumulation of RER was more frequent in A cells (NO:8.5%, SPX:13.1%, PX:7.7%) than in N cells (NO:2.8%, SPX:4.5%, PX:4.7%) (controls: P less than 0.001). Sham pinealectomy increased a large accumulation of RER in A cells (P less than 0.02) and a small aggregation of RER in N cells (P less than 0.005) with opposite effects of pinealectomy (P less than 0.005, P less than 0.025). Pinealectomy decreased a small aggregation of RER without effects of sham pinealectomy in A cells (P less than 0.001). CONCLUSIONS: (1) Accumulation or aggregation of RER in adrenomedullary chromaffin cells was influenced from the pineal gland either as or without effects of intracranial surgery, and (2) RER in adrenomedullary chromaffin cells showed differences due to cell types.

Adrenal Medulla↗
PubMed1992

Effect of methylxanthine derivatives on T cell activation.

In a Phase I-II trial examining the effect of prophylactic administration of pentoxifylline (PTX) on bone marrow transplant-associated morbidity, there was an apparent reduction in the incidence and severity of acute graft-versus-host disease. To determine if PTX might be directly immunosuppressive, its effects on T cell activation and proliferation were examined. PTX and several cogeners were found to directly suppress T cell proliferation in response to phytohemagglutinin, to allogeneic cells in a mixed leukocyte reaction, and to cross-linking the CD3 complex. The effects were dose-related and associated with suppression of secretion of tumor necrosis factor-alpha (TNF alpha). However, the inhibition of proliferation was not solely due to this effect since adding excess recombinant TNF alpha did not restore the proliferative response. These data suggest that PTX may be clinically useful in suppressing allogeneic reactions in bone marrow transplantation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1992

[Auto recording system for the Goldmann perimeter].

In order to develop a method for converting the Goldmann perimeter data directly for computer storage and evaluation, a recording instrument was designed as a modification of the Goldmann perimeter. By installing the two potentiometers on the pantographic arm and electrical switches, the position of the test target and the setting of the four levers which defines the size and the brightness of the test target were transferred directly to the computer. Accuracy of this recording system is better than 1.3 degree over the entire surface of the chart. This system will make it possible to easily follow changes in the visual fields of the same patient, i.e. shape change, numerical value.

Humans↗
PubMed1992

[Surgery versus detachable balloon embolization of pulmonary arteriovenous fistula: clinical experience].

We experienced 4 pulmonary arteriovenous fistula cases 2 of which were treated surgically and 2 were subjected to detachable balloon embolization therapy. Favorable results were obtained in the detachable balloon embolization therapy. In treating pulmonary arteriovenous fistula, if the lesion is in the position where the catheter can be reached easily and is composed of a single afferent-efferent vessel unit, it would be advisable to perform the embolization therapy first, and then to apply an operative procedure preserving lung tissue as much as possible.

Adult↗
PubMed1991

Intratesticular leiomyoma: a case report.

A case of leiomyoma of the testis is reported. The origin of the intratesticular leiomyoma is controversial, but recently it is thought to arise from the contractile cells in the tunica propria of the seminiferous tubules. This is the first case reported in Japan and the fifth in the world literature.

Adult↗
PubMed1979

Identification of benzo(a)pyrene metabolites by gas chromatograph-mass spectrometer.

A gas chromatograph-mass spectrometer was used in an attempt to achieve rapid separation and accurate identification of benzo(a)pyrene and its synthesized derivatives. All derivatives, after being trimethylsilylated, were developed on Dexsil-300 and OV-1 columns. The seven diols and four stereoisomeric 7,8,9,10-tetraols studied were separated successfully. The separation of the 12 phenols was unsatisfactory; 8- and 11-isomers appeared separately but the other 10 isomers made 3 peaks on the OV-1 column. Among the five derivatives reported to be present in animal tissues, 6-, 7-, and 9-phenols were separated, but 1- and 3-phenols were fused on the Dexsil-300 column. Quinones were converted to related dihydroxyl derivatives under silylation. The chromatographic separation of four of the six dihydroxyl derivatives was successful on the OV-1 column, but the 6,12- and 7,10-isomers remained in a single peak. The two diol-epoxides were unstable under silylation and therefore were detected by their breakdown products, 7,8,9-trihydroxy-7,8-dihydrobenzo(a)pyrene and tetraols. Data are listed on the mass spectra and retention times of all benzo(a)pyrene derivatives studied.

Benzopyrenes↗
PubMed1978

Retrocaval ureter in children. Report of two cases.

2 cases of retrocaval ureter in children diagnosed by the combination of pyelography and cavography are reported. Transection and repositioning of these ureters corrected their abnormality. Retrocaval ureter in children is briefly discussed.

Child↗
PubMed1978

Separation and identification of 3-methylcholanthrene-related compounds by gas chromatography-mass spectrometry.

Separation and identification of 3-methylcholanthrene and its synthesized derivatives were examined by gas chromatography-mass spectrometry (GC-MS) system. Hydroxyl derivatives were silylated and all chemicals were applied to columns of OV-1 and Dexsil-300 at a constant temperature of 260 degrees and 290 degrees, respectively. Mass spectra of all derivatives were simple at ionization voltage of 20 eV and their molecular ions gave base peaks in most cases. Mass fragmentography plotted against molecular ions satisfactorily separated all standard derivatives so far examined.

Gas Chromatography-Mass Spectrometry↗
PubMed1977

Metabolism of [3H]-methylcholanthrene in the perfused rat liver.

The metabolism of [3H]-3-methylcholanthrene (3-MC) was studied in the isolated, perfused rat liver. Following addition of 250 mug to the perfusion fluid, 3-MC disappeared rapidly. After 2 hr, approximately 34% of the radioactivity was excreted in the bile, 6% remained in the perfusate, and 60% was found in the liver. Of the liver radioactivity, 80% was unchanged 3-MC, 11% was conjugated metabolites, 4% was free hydroxymetabolites, and 4% was nonextractable, presumably bound to macromolecules. Of the perfusate radioactivity, 82% was conjugated metabolites, 3% was free hydroxymetabolites, and 15% was unchanged 3-MG. A similar distribution was observed in intact, bile-cannulated rats, but biliary excretion was about one-fourth as high with double the i.v.-injected dose. Biliary excretion in perfused livers rose rapidly during the first 30 to 40 min, then decreased steadily. It was nearly twice as high in male as in female rat livers. Pretreatment of rats with 3-MC more than doubled the biliary excretion rate over the first 20 to 30 min in livers of both sexes and raised that of the female to that of the male rat liver. Neither retinol acetate nor 7,8-benzoflavone had any appreciable effect on biliary excretion of 3-MC metabolites. 2-Diethylaminoethyl-2,2-diphenylvalerate, a well-known microsomal oxygenase inhibitor, lowered excretion by 80 to 90% and lengthened the lag period, and dibutyryl-3',5'-cyclic adenosine monophosphate markedly increased the rate of excretion of 3-MC metabolites. Fractionation of bile by chromatography on Sephadex LH-20 revealed six well-defined peaks of radioactivity. In contrast, bile of intact rats given 3-MC gave a pattern on Sephadex chromatography consisting of only three peaks. Preliminary data suggest that these consist of conjugates of dihydroxymetabolites as well as more highly hydroxylate derivatives. The data obtained indicate that the perfused liver is an appropriate experimental model for studies on the hepatobiliary metabolism of carcinogens.

Animals↗