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Biomedical subjects

Y Tsukada

Publications and source records attributed to Y Tsukada.

At least 343 records · Page 19Linked to original sources
PubMed1979

The differentiation of clonal rat yolk sac tumor cell lines cultivated with dibutyryl-cyclic 3', 5'-adenosine monophosphate.

Five rat yolk sac tumor cell lines were cloned from a yolk sac tumor line which originally arose following fetectomy. The doubling time of each of the cloned tumor lines was about 50 h. All of the cloned tumor cell lines synthesized and secreted AFP and albumin but there was a gradual decrease in the synthesis of these proteins during serial passage. The cells formed clusters which looked like vitelline ducts or the parietal yolk sac and they also had basement membranes which closely resembled Reichert's membrane. When the cloned cell lines were cultivated in the presence of 1 mM dibutyryl cyclic-AMP, myotube-like and neuron-like cells appeared. Acetylcholine esterase and creatine phosphokinase activity were present when myotube-like cells were present whereas acetylcholine esterase activity predominated when neuron-like cells were present.

Acetylcholinesterase↗
PubMed1979

Chemotherapy of nonirradiated malignant gliomas. Phase II: study of the combination of methyl-CCNU, vincristine, and procarbazine.

Twenty-eight adult patients with nonirradiated malignant gliomas of the brain were administered a combination of methyl-CCNU (130 mg/m2, p.o., day 1), vincristine (2 mg/m2, i.v., day 1) and procarbazine (100 mg/m2, p.o., days 2 to 15) (MVP), scheduled to be given at successive 6 week intervals. Nineteen (67.9%) were not responsive to MVP and 9 (32.1%) were. Of 16 who had previous partial resection of their tumors, 8 (50%) responded to MVP and 8 (50%) did not. Of 12 who had previous biopsy, only 1 (8.3%) responded. Overall 1-year survival rate for the 28 patients was 28.6%. Major side effects of MVP were leukopenia, thrombocytopenia, pulmonary emboli, and thrombophlebitis, detected mainly during the first 20 to 24 weeks of treatment.

Adult↗
PubMed1979

Fetal phenotypic expression by adult rat hepatocytes on collagen gel/nylon meshes.

Hepatocytes from adult rats were maintained in primary culture for up to 10-13 days on nylon meshes coated with a thin layer of rat tail collagen gel. Their ultrastructure closely resembled that of the liver parenchymal cell in vivo, but hepatocytes in late culture exhibited a pronounced buildup of microfilaments beneath their apical cell surface. Hepatocytes in early and late cultures secreted albumin, transferrin, and alpha1-acid glycoprotein into the medium; they exhibited a 7- to 10-fold induction of tyrosine aminotransferase activity by dexamethasone; and they expressed an alkaline phosphatase that was similar to that of normal rat liver with respect to its inhibition by the liver enzyme inhibitor L-homoarginine. In addition, the hepatocytes in culture demonstrated phenotypic changes characteristic of fetal liver parenchymal cells. These changes, which paralleled an increase in DNA synthesis, included the expression of and linear increase in the activity of the fetal liver cell enzyme gamma-glutamyl transpeptidase, an increased production of alpha1-fetoprotein, and a change in the substrate specificity of fructose-bisphosphate aldolase to that of the fetal liver isozyme.

Animals↗
PubMed1979

Enzymatic properties of neuraminidases from Arthrobacter ureafaciens.

Neuraminidase I and neuraminidase II from Arthrobacter ureafaciens were characterized. As determined by gel filtration on Ultrogel AcA 44, the molecular weights of neuraminidases I and II were 51,000 and 39,000, respectively. Neuraminidases I and II were similar to each other in their enzymatic properties except for the substrate specificities towards gangliosides and erythrocyte stroma. Their optimal pHs were between 5.0 and 5.5 with N-acetylneuraminosyl-lactose or bovine submaxillary mucin as substrates, but with colominic acid as a substrate, the pH optimum was between 4.3 and 4.5. They were most active around 53 degrees C, were stable between pH 6.0 and 9.0, and were thermostable up to 50 degrees C. They did not require Ca2+ for activity and were not inhibited by EDTA. They were inhibited only slightly or not at all by p-chloromercuribenzoic acid of Hg2+. Both neuraminidases I and II were able to hydrolyze the alpha-ketosidic linkage of N-glycolylneuraminic acid as well as that of N-acetylneuraminic acid, and were able to liberate substantially all of the sialic acid from various kinds of substrates. However, they cleaved only about 50% of the sialic acid from bovine submaxillary mucin. The saponification of bovine submaxillary mucin by mild alkali treatment, on the other hand, resulted in an increased susceptibility to the neuraminidases and brought about the complete liberation of sialic acid. Remarkable differences were observed between neuraminidases I and II as regards substrate specificities on gangliosides; the initial rate of hydrolysis by neuraminidase I was 74 times, and its maximum velocity constant was 91 times those of neuraminidase II. The addition of sodium cholate markedly stimulated the enzymatic hydrolysis of gangliosides, and increased the maximum velocity constant of neuraminidase I twofold and that of neuraminidase II 143-fold. Although neuraminidases I and II were able to hydrolyze (alpha,2-3), (alpha,2-6), and (alpha,2-8) linkages, the initial rate of hydrolysis of N-acetylneuraminosyl-alpha,2-6-lactose was greater than that of the alpha,2-3-isomer.

Arthrobacter↗
PubMed1979

A prospective trail comparing hysterectomy, hysterectomy plus vaginal radium, and uterine radium plus hysterectomy in stage I endometrial carcinoma.

From 1958 to 1967, a prospective randomized trial was conducted in 189 women with stage I, group I endometrial adenocarcinoma, comparing treatment by hysterectomy alone, preoperative uterine radium followed by hysterectomy, and hysterectomy and postoperative vaginal radium. All women have been followed for a minimum of 10 years. The actual survival rate at 5 years for all patients was 94.5% and at 10 years, 92.6%, with no statistical significance among the 3 treatment groups. Ther was also no statistical significance in survival rate in relation to size of uterine or myometrial invasion. There was a statistically significant difference in survival between grade I and grade III lesions (P less than 0.01) and between grade II and grade III lesions (P less than 0.05).

Adenocarcinoma↗
PubMed1979

Possible Involvement of the Alternative Respiration System in the Ethylene-stimulated Germination of Cocklebur Seeds.

Respiration of nondormant upper cocklebur (Xanthium pensylvanicum Wallr.) seeds was enhanced by exogenous C(2)H(4), proportionally to the concentration of C(2)H(4) and the duration of presoaking of the seeds. Benzohydroxamic acid (BHM) and salicylhydroxamic acid (SHM), inhibitors of alternative respiration, inhibited both the germination of nondormant lower cocklebur seeds and the respiration of the upper seeds presoaked for periods of 12 to 30 hours. Both the growth and respiration of axial and cotyledonary tissues were also inhibited by BHM. Moreover, BHM inhibited both the C(2)H(4)-induced germination of the upper seeds and their C(2)H(4)-stimulated respiration; the inhibition occurred only with concomitant addition of C(2)H(4) and BHM. The respiration of seeds with a secondary dormancy induced by presoaking for prolonged periods was markedly stimulated by C(2)H(4) but not suppressed by BHM. It was suggested that the alternative respiration system may be involved in the normal germination process of cocklebur seeds, secondary dormancy may result from its inactivation, and C(2)H(4) may exert its germination-promoting action by stimulating the alternative respiration. The effects of BHM and SHM can suggest but not prove the involvement of the alternative respiration in seed germination.

Journal Article↗
PubMed1979

Five patients with nonalcoholic diabetic cirrhosis.

Five nonalcoholic diabetic women were clinically and histologically verified as having micronodular cirrhosis. In this series all the patients were over 50 years of age, and showed obesity, hyperglycemia, enlarged liver and mild abnormalities of liver function tests. The histological findings differed from hepatitic cirrhosis. In two patients serial biopsies confirmed development of cirrhosis from centrilobular necrosis.

Aged↗
PubMed1978

Plasma cell neoplasm involving the thyroid.

Involvement of the thyroid gland by plasma cell neoplasms is very rare. On review of 248 cases, we found 4 cases in which pathological evidence of plasma cell neoplasm in the thyroid was verified. This was a heterogeneous group of patients; the thyroid involvement was clinically recognized as a site of extramedullary plasma cell neoplasm in one patient and as a part of generalized disease in two patients. In another patient with generalized disease, the thyroid involvement was discovered at autopsy.

Adult↗
PubMed1978

Ouabain induced seizures: site of production and response to anticonvulsants.

Ouabain, an inhibitor of Na+ -K" -ATP'ase, has been administered intraventricularly to rats to study the effect of impairment of membrane transport mechanisms on the genesis of seizures. Running and leaping seizures occur rapidly after injection of ouabain in a low volume (10 microliter) when the maximal uptake of ouabain (39.8%) is the hippocampus. Generalized clonic-tonic seizures are induced by higher volume injections (50 microliter) associated with wider distribution of ouabain, including the cerebellum and brainstem. Ouabain was injected into cerebral cortex, caudate nucleus, dorsal hippocampus, fastigeal nucleus, ventrolateral mesencephalic reticular formation and cerebellar cortex. The cerebellar injections produced both running and leaping and generalized clonic-tonic seizures. It is suggested that this results from decreased inhibitory effect of vermal and paravermal Purkinje cells on intra-cerebellar nuclei, which alters cerebellar influence on the reticular formation and the limbic system. Diphenylhydantoin, phenobarbitone, phenacemide, carbamezepine and clonazepam but not ethosuximide are effective against generalized clonic-tonic seizures, suggesting that this is a model for "grand mal" but not "petit mal" seizure mechanisms. It is furthermore suggested that running and leaping are subcortical, probably limbic, seizures that are most relevant as a model for temporal lobe seizures.

Animals↗