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Biomedical subjects

Y Kubo

Publications and source records attributed to Y Kubo.

At least 415 records · Page 23Linked to original sources
PubMed1981

Synaptic basis of orbital cortically induced rhythmical masticatory activity of trigeminal motoneurons in immobilized cats.

Synaptic basis of the centrally induced masticatory rhythm was studied by intracellular recording from jaw closer and opener motoneurons during repetitive stimulation of the orbital gyrus (OG) of the encéphale isolé of immobilized cats, with the following results. (1) Repetitive OG stimulation induced a rhythmical alternation of hyperpolarizing and depolarizing potentials in jaw closer motoneurons. Rhythmical efferent burst discharges induced in the digastric nerve by OG stimulation coincided with the hyperpolarizing phase. The hyperpolarizing potential was reversed to a depolarizing potential by intracellular Cl- injection, while the depolarizing potential was not reversed to hyperpolarization, indicating that the hyperpolarizing and depolarizing potentials consisted at least mainly of IPSPs and EPSPs, respectively. (2) Repetitive OG stimulation induced rhythmical depolarizing potentials superimposed by spike bursts in jaw opener motoneurons, corresponding in time with the rhythmical efferent bursts in the digastric nerve. Synaptic activation noise was increased coincidentally with the depolarizing potential, indicating that EPSPs were involved in the generation of the depolarizing potential. No or little hyperpolarization if any was observed between successive depolarizing potentials. (3) Repetitive OG stimulation induced efferent burst discharges in the digastric nerve with the masticatory rhythm unaccompanied by any spike potential in the supratrigeminal neurons responsible for peripherally evoked inhibition of jaw closer motoneurons, indicating that the peripheral inhibitory mechanisms do not play an essential role in the central generation of the masticatory rhythm by OG stimulation.

Animals↗
PubMed1981

Difference in phosphorylation of two factors stimulating RNA polymerase II of Ehrlich ascites tumor cells.

The structures of two protein factors, S-II and S-II', that specifically stimulate RNA polymerase II from Ehrlich ascites tumor cells were compared. The two proteins behaved differently on CM-cellulose chromatography and on isoelectric focusing, although they were shown to have common antigenicity. The following findings strongly suggest that S-II and S-II' have the same primary structure, but that S-II' is more extensively phosphorylated than S-II: (1)S-II an S-II' gave identical peptide maps when digested with various proteases. (2) S-II' that had been treated with alkaline phosphatases had the same mobility on sodium dodecyl sulfate-polyacrylamide gel as S-II, indicating that it could be converted to S-II by hydrolysis of its phosphate residues. (3) S-II' was phosphorylated more than S-II when Ehrlich ascites tumor cells were labeled in vivo with [32P]orthophosphate.

Alkaline Phosphatase↗
PubMed1981

A clinical and pathological study of diffuse type hepatocellular carcinoma.

Six autopsy cases of the rare, diffuse type of hepatocellular carcinoma (HCC), as classified gross anatomically according to the strict definition, have been studied. The prominent clinical feature was the rapid deterioration of the patient's general condition, terminating in hepatic failure. The liver size enlarged quickly, at a perceptible speed, often accompanied by abdominal pain. Diagnosis of this particular type of HCC was difficult, and celiac angiography and scintiscan of the liver were only suggestive when considered together with other laboratory data. Hepatitis B surface antigen was positive in all three patients in whom it was tested. The entire liver was studded with minute, uniformly sized tumor nodules, evenly distributed throughout. Some of them were grossly indistinguishable from cirrhotic nodules. All livers had an underlying cirrhosis which was characterized by relatively small regenerative nodules with thin stromas. Large portal branches at the hilum contained tumor thrombi in all patients, except for one case in which left lobectomy was followed by intraportal dissemination. Histologically, all tumor nodules represented intrahepatic metastases via the portal vein system. Tumor cells were poorly differentiated. These findings suggest that the diffuse type of HCC most frequently, if not always, represents intrahepatic, widespread portal metastases which have occurred within a short period of time.

Adult↗
PubMed1980

Wall reinforcement with highly porous Dacron mesh in aortic surgery.

Wall reinforcement with highly porous synthetic Dacron mesh was devised and evaluated in various aortic operations. Excellent attachment of the mesh to the aortic wall, good preservation of pliability of the aorta, and efficient pressure resistance with minimal scar tissue formation were the usual findings. This type fo wall reinforcement was employed in 60 patients for the following indications: 1) prevention of suture line complications; 2) wall reinforcement of aortic aneurysm without resection; 3) reinforcement of adventitia or autogenous vein following thromboendarterectomy. It is concluded that reinforcement with highly porous synthetic Dacron mesh should be superior to reinforcement with conventional prosthetic Dacron graft.

Aorta↗
PubMed1980

Small multiple carcinoid tumors occurring in the ileum with a pseuodcystic liver metastasis.

A 49-year-old woman was admitted to the hospital with a palpable mass in the right hypochondrium. A laparotomy was performed under the clinical diagnosis of a solitary cyst of the liver. The cystic lesion of the liver was removed. Although the histological finding of the cyst wall showed a similarity to hepatocellular carcinoma of trabecular pattern, the tumor cells with uniform nuclei and little mitotic figure were positive for both argyrophil and argentaffin reaction. The pathological diagnosis was metastatic carcinoid tumor of the liver. There was no carcinoid syndrome nor the other clinical symptoms after the operation and various postoperative examination could not reveal a primary site of the carcinoid tumor. The cystic lesion of the liver recurred ten months after the first operation and a second laparotomy was performed to reveal the primary site in the ileum: three submucosal tumors, 0.8, 0.7, and 0.3 cm. in diameter, two of them, however, extended into the muscle wall or subserosa and conclusively, the small lesion of the ileum metastasized into the liver as a large pseudocystic lesion.

Carcinoid Tumor↗
PubMed1979

Some lipogenic enzyme activities in rat livers in which an excessive fat accumulation occurred due to feeding low-level amino acid mixture diets.

In liver homogenates of rats fed a low-level diet of Wheat-Rice- or Miyazaki-pattern amino acid mixture, some enzymes such as glucose-6-phosphate dehydrogenase, ATP citrate lyase, fatty acid-synthesizing enzymes, malic enzyme and L-alpha-glycerophosphate dehydrogenase, whose activities are indicators of lipogenesis have been determined from the viewpoint of the mechanisms producing fatty liver. In the early experimental period, malic enzyme activity increased more markedly in rats fed low amino acid mixture diets than in the control group, and L-alpha-glycerophosphate dehydrogenase activity in the liver increased slightly. Conversely, ATP citrate lyase and fatty acid-synthesizing enzyme activities remained almost at control levels, or glucose-6-phosphate dehydrogenase activity tended to decrease. These results suggest that some other associated factors, such as depression of the lipid transfer system in the liver rather than accelerated lipogenesis itself, may be the main cause of the fatty livers produced under these nutritional conditions.

ATP Citrate (pro-S)-Lyase↗
PubMed1979

Formation of roseoflavin from guanine through riboflavin.

A synthesis of roseoflavin by Streptomyces davawensis from guanine through riboflavin was demonstrated. The lines of evidence are (1)incorporations of 14C of [2-and U-14C] guanine and [2-14C] riboflavin into roseoflavin, (2) no incorporation of 14C of [8-14C] guanine into roseoflavin, (3) localizations of 14C in roseoflavin, and (4) a decrease of specific radioactivity of roseoflavin formed from [2-14C]guanine on addition of riboflavin to the culture. The 14C atoms in roseoflavin formed were localized by radioactivity analysis of the NaOH-hydrolysis products, i.e., urea and 1,2-dihydro-6-methyl-7-dimethylamino-2-keto-1-D-ribityl-3-quinox-alinecarboxylic acid (QC), a new substance. These hydrolysis products were identified by the isolation of dixanthylures, decomposition with urease, and from the properties of QC and QC tetraacetate isolated. These finding suggest that the pyrimidine ring of guanine is conserved in the formation of roseoflavin from guanine through riboflavin.

Anti-Bacterial Agents↗