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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 577 records · Page 32Linked to original sources
PubMed1983

Marked reduction of ANAE reactivity of T cells in the lymphoid tissues of monkeys treated with multiple high doses of human beta interferon.

We report a histological study of the organs and tissues of cynomolgus monkeys which had received multiple high doses of human beta interferon (IFN). There were dense aggregations of small lymphocytes without the acid alpha-naphthyl acetate esterase (ANAE) reactivity in the thymus-dependent areas (TDA) of lymphoid tissues, indicating that the T mu cells of IFN-treated monkeys had lost this characteristic enzyme. This change of T mu cells in the tissues was not accompanied by a change in circulating T mu cells.

Animals↗
PubMed1983

[Primary adenosquamous carcinoma of the ileum--a case report].

A 41-year-old woman with a mass of the right lower abdominal quadrant was admitted to our hospital. Ileocecal resection was performed on December 30, 1975; and she is in good health at present. The resected specimen showed a protruded tumor with a central excavation at the terminal ileum; there was a small cyst in the submucosal layer. Histologically, most of the tumor consisted of squamous cell carcinoma. A small nest of squamous metaplasia and adenocarcinoma was observed at the cyst wall. The pathological diagnosis was adenosquamous carcinoma arising from an enterogenous cyst of the ileum.

Adenocarcinoma↗
PubMed1983

[Endobronchial metastasis of testicular embryonal cell carcinoma--a case report].

Four cases of endobronchial metastasis in testicular embryonal cell carcinoma have been reported in the literature. We now present a new case, a 39-year-old male who underwent right orchiectomy for testicular embryonal cell carcinoma. Ten months later, tumor like shadows were identified in the left upper lobe on a follow up chest X-ray. Bronchoscopy revealed an endobronchial tumor mimicking a bronchogenic carcinoma in the left superior posterior bronchus. A metastatic embryonal cell carcinoma of the testis was histologically diagnosed. Left upper lobectomy was performed, and the patient is still alive 11 months thereafter.

Adult↗
PubMed1983

[Evaluation of constrictive pericarditis by computed tomography].

Since extensive studies of constrictive pericarditis by CT have not been reported, we performed a plain and contrast enhanced CT on 4 patients of constrictive pericarditis diagnosed by cardiac catheterization or echocardiography and confirmed at the time of surgical operation. The CT findings were as follows: The normal pericardium was smooth, could be visualized in the right and anterior regions of the heart, and was approximately or less 2 mm in thickness. On the other hand, the pericardium in constrictive pericarditis was irregularly thickened, was visualized even in the left and posterior regions of the heart, and was more than 2 mm in thickness. The mean CT value of the pericardium in constrictive pericarditis was significantly increased as compared with that of the normal pericardium. The contrast enhanced CT image revealed a marked dilatation of superior and inferior caval veins (SVC and IVC) even in the cases with normal size of each cardiac chamber. The ECG gated CT performed on one case demonstrated the impaired ventricular expansion. After pericardiectomy, the ventricular chambers showed a tendency to dilate, and the dimension of the SVC and IVC were reduced. Thus, CT is thought to be a useful noninvasive technique in evaluating the thickness of the pericardium, its pathology and the degree of dilatation in each cardiac chamber or the vena cavae.

Adult↗
PubMed1983

[Case of gastric cancer associated with acanthosis nigricans and meningeal carcinomatosis].

The patient was a 61-year-old man who initially complained of skin pigmentation. He was diagnosed as malignant acanthosis nigricans associated with gastric cancer (IIc advanced) in March 1981. Surgical excision of the stomach was performed in May 1981. In July 1981 he experienced headache, vomiting and muscle weakness. A diagnosis of meningeal carcinomatosis was made based on his clinical symptoms, spinal fluid examination and a computerized tomography scan. The intraventricular administration of cytosine arabinoside, methotrexate and hydrocortisone via the Ommaya reservoir resulted in complete remission. In November 1981 the patient died of bronchopneumonia and sepsis due to pancytopenia.

Acanthosis Nigricans↗
PubMed1982

A selenium-containing hydrogenase from Methanococcus vannielii. Identification of the selenium moiety as a selenocysteine residue.

A 75Se-labeled hydrogenase was purified to near homogeneity from extracts of Methanococcus vannielii cells grown in the presence of [75Se]selenite. The molecular weight of the enzyme was estimated as 340,000 by gel filtration. The enzyme tends to aggregate and occurs also as a larger protein species (Mr = 1.3 x 10(6)). The same phenomenon was observed on native gel electrophoretic analysis. Hydrogenase activity exhibited by these two protein bands was proportional to protein and 75Se content. Both molecular species reduce the natural cofactor, 8-hydroxy-5-deazaflavin, and tetrazolium dyes with molecular hydrogen. Sodium dodecyl sulfate-gel electrophoresis of 75Se-labeled enzyme showed that 75Se is present exclusively in an Mr = 42,000 subunit. A value of 3.8 g atoms of selenium/mol of enzyme (Mr = 340,000) was determined by atomic absorption analysis. The chemical form of selenium in the enzyme was shown to be selenocysteine. This was identified as the [75Se]carboxymethyl and [75Se]carboxyethyl derivatives in acid hydrolysates of alkylated 75Se-labeled protein. The hydrogenase is extremely oxygen-sensitive but can be reactivated by incubation with molecular hydrogen and dithiothreitol.

Cysteine↗
PubMed1982

Analogues of 8-hydroxy-5-deazaflavin cofactor: relative activity as substrates for 8-hydroxy-5-deazaflavin-dependent NADP+ reductase from Methanococcus vannielii.

The 8-hydroxy-5-deazaflavin-dependent NADP+ reductase from Methanococcus vannielii was examined for its ability to catalyze the reduction of a number of 5-deazaflavin analogues of the natural cofactor. Comparison of the kinetic constants revealed certain substrate structure-reactivity relationships for the enzyme. The basic heterocyclic system of the natural cofactor 2,4-dioxopyrimido [4,5-b]quinoline was shown to be the minimum structural requirement since neither riboflavin nor 1,5-dideazariboflavin was reduced by the enzyme. The N-10 side chain of the natural cofactor was shown not to be essential since the enzyme could reduce 8-hydroxy-2,4-dioxopyrimido[4,5-b]quinoline. The study also indicated that there are some steric constraints at C-8 and C-7 with respect to interaction of the cofactor with the enzyme. Specifically, (a) the 8-methoxy derivative, in contrast to the 8-hydroxy compound, was not reduced and (b) the introduction of a substituent at C-7 resulted in a marked decrease in the rate of reduction. The importance of C-5 as the site for the electron entry was suggested by the finding that 5-methyl-deazariboflavin was not reduced. The latter inhibited the reduction of 5-deazariboflavin.

Euryarchaeota↗
PubMed1982

The pathogenesis of abnormal cytoarchitecture in the cerebral cortex and hippocampus of the mouse treated transplacentally with cytosine arabinoside.

Pregnant mice were treated with cytosine arabinoside on days 13.5 and 14.5 of pregnancy. Brains of the offspring were studied histologically. The matrix layer of the embryonic brains was extensively destroyed 12 h after the injection of cytosine arabinoside, but regenerated partially on day 17 of gestation. In the cerebral cortex of 1-, 3-, and 5-day-old treated mice, abnormal clusters of young neurons were found on the surface of the developing cerebral cortex. Some clusters still had a supply of immature neurons from the remnants of the regenerated matrix layer. After 20 days, the clusters became gradually indistinct, although some vestigial groups of neurons were observed even after 120 days. In the hippocampus of young mice, the pyramidal cells decreased in number and were disarranged. Heterotopic pyramidal cell masses were found in the stratum radiatum and in the molecular layer of the dentate gyrus. Apical dendrites of pyramidal cells exhibited abnormal arborization. It was demonstrated by 3H-thymidine autoradiography that young neurons in the abnormal clusters in the cerebral cortex were those produced in the matrix layer regenerated after the destructive change by cytosine arabinoside.

Abnormalities, Drug-Induced↗
PubMed1982

Resection of the trachea infiltrated by thyroid carcinoma.

Twenty-four thyroid carcinoma patients with infiltration of the trachea were treated surgically. The histological diagnosis in these cases included papillary adenocarcinoma in 22 different patients, medullary carcinoma in one patient, and undifferentiated carcinoma in one patient. In 19 of the patients hemoptysis was noted, and dyspnea was present in ten patients. In 14 of the 24 patients the carcinoma was diagnosed by radiographs of the neck, while in seven patients it was demonstrated bronchoscopically. In three patients tracheal infiltration by thyroid carcinoma was diagnosed by biopsy of the tracheal wall at operation. When the tracheal wall was infiltrated by thyroid carcinoma, treatment consisted of circumferential resection of the involved segment of the trachea followed by an end-to-end anastomosis. Of the 24 patients, 17 survived and six died. In the 17 patients who survived, 13 were disease free. Of this number, six survived more than five years after the initial tracheal resection.

Adenocarcinoma, Papillary↗
PubMed1982

Characterization of a temperature-sensitive defect of enterovirus type 70.

The mechanism of the failure of enterovirus type 70 to replicate at a nonpermissive temperature (39 degrees C) was investigated, and the following results were obtained. (i) Viral RNA synthesis was not observed at 39 degrees C in LLC-MK2 cells, in accordance with our previous findings with primary monkey kidney cells (Miyamura et al., Intervirology 9:206-213, 1978). (ii) Shutoff of host cell macromolecular synthesis by virus infection was as efficient at 39 degrees C as at a permissive temperature (33 degrees C). This inhibitory effect similarly occurred even in the presence of guanidine hydrochloride. (iii) Viral protein synthesis proceeded in vivo at the nonpermissive temperature, and the rate of the protein synthesis was higher than that at the permissive temperature under the conditions in which sufficient viral mRNA had been accumulated. This was also confirmed by analyzing the intracellular proteins synthesized at the nonpermissive temperature by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which identified them as virus-specific proteins. (iv) When infected cells were incubated at 39 degrees C and then transferred to 33 degrees C, viral RNA synthesis took place even in the presence of cycloheximide. (v) Furthermore, in experiments performed with an in vitro cell-free assay system, viral polymerase activity was found in the membrane-bound preparation extracted from infected cells which had been incubated at 39 degrees C in the presence or absence of guanidine hydrochloride. These results indicate that early translation of mRNA proceeds normally at the nonpermissive temperature and that the temperature-sensitive defect resides in the transcriptional stage.

Animals↗