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Biomedical subjects

M Tateishi

Publications and source records attributed to M Tateishi.

At least 73 records · Page 4Linked to original sources

Possible involvement of Epstein-Barr virus (EBV) in polyclonal B-cell activation in Sjögren's syndrome.

The following results suggest that EBV might be involved in the mechanism of polyclonal B-cell activation of Sjögren's syndrome (SS). (1) The levels of serum anti-VCA antibodies of both IgG and IgM class were significantly elevated in SS. (2) Excretion of EBV from the oropharynx was frequently observed in SS. (3) Spontaneously transformed B-cell lines producing a large amount of transforming EBV were established preferentially from SS. (4) An EBV-specific regulatory mechanism was impaired in SS.

Adult↗

[Malignant hyperthermia; two cases of MH in the presence of general anesthesia and performing caffeine contracture test].

In the present report we described two cases of malignant hyperthermia under halothane anesthesia. Case 1; A 54-year-old, 58 kg-male was scheduled for the operation of giant arterio-venous malformation. Anesthesia was induced with thiamylal, fentanyl and pancuronium, and maintained with oxygen, nitrous oxide and halothane. The patient was subjected to halothane inhalation for 26 hours prior to the development of the malignant hyperthermia. Although body temperature rose to 41 degrees C, it returned to normal with the administration of 280 mg of dantrolene and systemic cooling. Case 2; A 31-year-old, 68 kg-female was scheduled for tonsillectomy. Anesthesia was induced with thiamylal, oxygen, nitrous oxide and halothane. After the administration of 70 mg of SCC, marked muscular rigidity occurred and endotracheal intubation was impossible. The operation was postponed. Two months after the first anesthesia, operation was successfully performed under NLA with droperidol and fentanyl. Caffeine contracture test was performed in each case by skinned fiber method and the result showed that the sensitivity to caffeine increased in the isolated skeletal muscle fiber bundles from these patients. Thresholds of caffeine contracture of these skinned fiber bundles were all lower than 5mM caffeine.

Adult↗

Transamination of LTE4 by cysteine conjugate aminotransferase.

Leukotriene E4 (LTE4) was transaminated to 5(S)-hydroxy-6(R)-S-(2-keto-3-thiopropionyl)-7,9-trans-11,14-cis- eicosatetraenoic acid (tentatively designated as LTG4) by cysteine conjugate aminotransferase I purified from rat liver supernatant in the presence of alpha-ketoglutaric acid or alpha-keto-gamma-methiolbutyric acid. The transamination activity was present in the kidney as well as in the liver, but not in the lung or leukocytes.

Animals↗

Determination of 5-fluorouracil in plasma and liver after oral administration of 5'-deoxy-5-fluorouridine using gas chromatography-mass spectrometry.

A method for determination of 5-fluorouracil (5-FU) has been established for pharmacokinetic study of 5'-deoxy-5-fluorouridine (5'-DFUR), a newly developed prodrug of 5-FU. 5-FU was extracted with diethyl-ether containing 1-propanol and methylated with CH3I in the presence of (CH3)4NOH. The methylated 5-FU was analyzed by gas chromatography-mass spectrometry using 15N2-5-FU as an internal standard. Quantitation was carried out by selected-ion monitoring of molecular ions of N,N-dimethyl-5-FU (m/z 158) and the internal standard (m/z 160). The sensitivity (greater than 2 ng/g sample), specificity and precision of the method were satisfactory for application to clinical studies of this drug. After an oral administration of 5'-DFUR (800 mg/body) to patients with cancer, 5-FU in plasma peaked within 1 h and eliminated with an apparent half life of about 1 h.

Administration, Oral↗

Purification and characterization of cysteine conjugate transaminases from rat liver.

1. Soluble cysteine-conjugate alpha-ketoglutarate transaminase (CAT-I) was purified about 670-fold from rat liver cytosol using s-(p-bromophenyl)-L-cysteine as amino acid substrate. The enzyme preparation of the final step of purification showed a single band in polyacrylamide gel electrophoresis. CAT-I accounted for 64% of the transaminase activity in cytosol. 2. The mol. wt of the enzyme was about 64,000 as determined by gel filtration. Respective Km values for s-(p-bromophenyl)-L-cysteine and alpha-ketoglutaric acid were 1.0 and 1.3 mM in Tris-acetate buffer (pH 7.0). Aminooxyacetic acid, hydroxylamine, and KCN inhibited the enzyme activity. 3. In addition to CAT-I, two isozymes (CAT-IIA and CAT-IIB) were partially purified from rat liver cytosol. In respect of mol. wt, substrate specificity towards cysteine conjugates, and several other properties, CAT-IIA and CAT-IIB were very similar to CAT-I. However, differences were observed for these enzymes in the rate of reverse reaction (formation reaction of cysteine conjugates and alpha-ketoglutaric acid) and substrate specificity towards L-aspartic acid and L-cysteinesulphinic acid.

Animals↗

Involvement of cystathionase in the formation of alkane-thiols from corresponding cysteine conjugates.

1. Rat liver cystathionase [EC.4.4.1.1] mediated a cleavage reaction of the C-S bond of S-alkyl-L-cysteine conjugates to give equimolar amounts of corresponding thiols, ammonia, and pyruvic acid. Neither S-aryl- nor S-aralkyl-L-cysteine conjugates were acceptable substrates. 2. The Km value for S-(tert-butyl)-L-cysteine was 0.3 mM at pH 8.5 in Tris-HCl buffer. 3. The S-alkyl-L-cysteine lyase activity of cystathionase was inhibited with carbonyl reagents and dithiothreitol. 4. The present finding that cystathionase has activity towards cysteine conjugates may provide some insights into the role of this enzyme in the metabolism of xenobiotics.

Alkanes↗

[A case of double cancer: renal pelvic transitional cell carcinoma and lung squamous cell carcinoma].

A 69-year-old woman was admitted with the chief complaint of gross hematuria and left flank pain ten years after curative right pneumonectomy. Retrograde pyelography showed a filling defect of inferior calyx. Computerized tomography revealed a solid tumor with a low density area arising from the left kidney. The tumor was demonstrated hypovascular by angiography. Left radical nephrectomy by a transabdominal approach was performed. Histological diagnosis was primary transitional cell carcinoma of the left renal pelvis largely replacing the renal parenchyma. Twenty six days after the operation she was discharged. Our case was of double cancer consistent with Warren and Gates criteria and was classified into the nonsimultaneous case according to Moertels criteria. Double cancer of the lung and renal pelvis is very rare and our case seems to be the 7th in the Japanese clinical literature.

Aged↗

Purification and properties of methyl sulfoxide reductases from rat kidney.

Two kinds of enzymes (tentatively designated methyl sulfoxide reductases I and II) responsible for the reduction of the methyl sulfoxide group on various xenobiotics have been purified about 223- and 155-fold, respectively, from rat kidney cytosol. The molecular weight was determined to be 12,000 +/- 1000 for methyl sulfoxide reductase I and 24,000 +/- 1000 for methyl sulfoxide reductase II. Thioredoxin or dithiothreitol is essential in order for the reducing activity to occur. The respective Km values of p-bromophenylmethyl sulfoxide were 2.75 and 1.30 mM for methyl sulfoxide reductases I and II. Replacement of the methyl group on the sulfur atom with a longer alkyl group or phenyl group caused a markedly low or negligible substrate activity.

Animals↗

Involvement of leukocytes in the oxygenation and chlorination reaction of phenylbutazone.

A center carbon atom of 1,3-diketone moiety of phenylbutazone was oxidized to give three metabolites--4-hydroxyphenylbutazone (metabolite I), 4-hydroperoxyphenylbutazone (metabolite II) and 4-chlorophenylbutazone (metabolite III)--by the action of enzymes present in leukocyte extract obtained from peritoneal exudate of rats. Both metabolites II and III were produced by peroxidases, while metabolite I was produced by enzymes other than the peroxidases.

Animals↗

Purification and characterization of human hepatic cysteine-conjugate beta-lyase.

Cysteine-conjugate beta-lyase (EC 4.4.1.13) was purified about 880-fold from human liver obtained post mortem. The purification procedure included (NH4)2SO4 precipitation, chromatography on DEAE-cellulose and hydroxyapatite, gel filtration on Sephadex G-200, and chromatofocusing. The purified enzyme cleaves the C-S bond of several S-aryl-L-cysteines to yield equimolar amounts of thiols, pyruvic acid and ammonia via an alpha beta-elimination reaction. The Mr of the enzyme was estimated to be 88,000 by gel filtration. The enzyme is thermolabile, has a pH optimum of 8.5, and an apparent Km of 0.7 mM towards S-(p-bromophenyl)-L-cysteine. The enzyme requires pyridoxal 5'-phosphate as a cofactor, and hence the enzyme activity was completely abolished by hydroxylamine. No effect of EDTA or thiol-blocking reagents was observed on the activity of the enzyme.

Carbon-Sulfur Lyases↗

A histopathological study of carcinoma of the larynx.

Fifty-one laryngectomy specimens were histopathologically studied in serial sections. The incidence of thyroid cartilage invasion was 10% in supraglottic, 48% in glottic, and 67% in subglottic carcinomas. The incidence of cricoid cartilage invasion was 0% in supraglottic, 22% in glottic, and 33% in subglottic carcinomas. The sites of cartilage invasion were the anterior commissure portion and an ossified lower portion of the thyroid cartilage, and an ossified upper portion of the cricoid cartilage. Fixation of the vocal fold in glottic carcinoma was accounted for by carcinomatous invasion into three-fourths or more of the thyroarytenoid muscle. Impairment of the vocal fold movement was accounted for by carcinomatous invasion into three-fourths or less of the thyroarytenoid muscle. Fixation of the vocal fold in supraglottic carcinomas was accounted for by a massive carcinomatous invasion around the upper aspect of the arytenoid cartilage.

Arytenoid Cartilage↗