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Biomedical subjects

Y Tsukada

Publications and source records attributed to Y Tsukada.

At least 361 records · Page 20Linked to original sources

Microinvasive carcinoma of the vulva.

A case is presented of a patient with microinvasive carcinoma of the vulva which was treated by conservative surgery. Six years later, the patient developed inguinal and pelvic lymph node recurrence of carcinoma. A review of the literature on similar cases is also presented.

Carcinoma in Situ↗

Thermoperiodism in cocklebur seed germination.

Germination potential in nondormant, upper cocklebur (Xanthium pensylvanicum Wallr.) seeds, which were incapable of germinating under constant temperatures below 25 C in air, was increased by exposure to diurnally alternating temperatures. The cocklebur seeds failed to respond to the temperature fluctuations in the beginning of water imbibition, and their responsiveness appeared only after aerobic presoaking for a limited period or after anaerobic pretreatment for 1 to 3 days.Maximal germination was obtained after exposure to a thermoperiodic regime of 8 hours at 23 C and 16 hours at 8 C. A process occurring during the high temperature phase was aerobic and had to precede the inductive low temperature phase, its effect increasing with temperature. Critical minimum length of the inductive low temperature phase changed with the duration of a preceding anaerobiosis, for instance about 4 hours after 1 day anaerobiosis, but about 2 hours after 2 days. Percentage of subsequent germination was in proportion to the number of thermoperiodic cycles. A process of the inductive low temperature phase was not perturbed by inserting a brief higher temperature period into its phase; indeed, such insertion rather increased germination potential when performed in the earlier parts of the inductive low temperature phase. The effect of the low temperature survived for 13 to 17 hours during the higher temperature period.

Journal Article↗

Experimental yolk-sac tumors produced by fetectomy without virus infection in rats.

Pregnant WKA rats were laparotomized on the 12th day of gestation, and all fetuses were removed from the uteri, leaving the fetal membranes attached to placentas in situ, protruding into the peritoneal cavity. After 5 to 6 months, extrauterine tumors were observed in 80% of the operated rats, and elevated serum alpha-fetoprotein levels were detected in 80% of the tumor-bearing rats. The tumors in AFP-positive rats always contained yolk-sac tumor elements. In transplantable tumor lines established in the ascites form, numerous free-floating embryoid bodies were observed. The experiments demonstrate that yolk-sac tumors (endodermal sinus tumors) can be induced by simple fetectomy without infection by exogenous tumor virus.

Animals↗

Distribution of neuraminidase in Arthrobacter and its purification by affinity chromatography.

Neuraminidase [sialidase, EC 3.2.1.18] was found to be widely distributed in bacteria belonging to Arthrobacter. Among these bacteria, Arthrobacter ureafaciens, A. oxydans, and A. aurescens produced relatively potent neuraminidase activities. For the production of this enzyme, not only colominic acid, a homopolymer of N-acetylneuraminic acid, but also N-acetylneuraminic acid, the reaction product of this enzyme, are effective as sources of carbon. An affinity adsorbent specific for neuraminidase was prepared by cross-linking colominic acid with soluble starch by means of epichlorohydrin. Neuraminidase from A. ureafaciens could be purified on this affinity column. The purified neuraminidase was shown to be free from protease, N-acetylneuraminic acid aldolase, phospholipase C, and glycosidases. Aminoff's assay procedure for sialic acid was modified to avoid the centrifugation step. The modified procedure gave a higher molecular extinction coefficient.

Arthrobacter↗

Effects of manganese, calcium, magnesium and lithium on the ouabain-induced seizure.

The effects of the intraventricularly administered cations (Mn2+, Ca2+, Mg2+ and Li+) against the seizure induced by ouabain (3 microgram) were investigated. Mn2+, Ca2+ and Mg2+ caused definite sedation and decreased locomotor activity. But Li+ was without significant behavioral effect at the doses applied. Among the cations used, Mn2+, Ca2+ and Mg2+ showed significant anticonvulsive effect on the ouabain-induced seizure. In comparison, on the dose and molar-to-molar basis, the potency of anticonvulsive action was in the following order: Mn2+ greater than Ca2+ greater than Mg2+. On the contrary, the higher dose of Li+ potentiated the ouabain-induced seizure. The importance of the increased Ca2+ level in the extracellular space or the inhibition of Ca2+ uptake as the anticonvulsive effect of Ca2+, Mn2+ and Mg2+ was discussed.

Animals↗

Nonalcoholic fatty liver with alcoholic hyalin after long-term glucocorticoid therapy.

Alcoholic hyalin was found in liver of a nonalcoholic patient with fatty liver after long-term glucocorticoid therapy for systemic lupus erythematosus. Hepatocytes including hyalin bodies showed fatty change or vesiculated degeneration. Occasionally, basophilic substance which was recognized in the hepatocytes with or without hyalin was noticed showing the feature quite similar to delicate alcoholic hyalin.

Adult↗

Dysgerminoma of the ovary: radiation therapy for recurrence and metastases.

Nine cases of dysgerminoma are reported. Five patients developed recurrence of disease in either the pelvis or metastatic sites including the lung and brain. The metastatic disease was controlled by a radiation dose of 2,000 to 3,000 rads during three to four weeks in four of the patients. The excellent response of dysgerminoma to radiation warrants an optimistic prognosis and vigilant follow-up since metastatic disease can be controlled by moderate radiation doses.

Adolescent↗