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Biomedical subjects

M Takeuchi

Publications and source records attributed to M Takeuchi.

At least 811 records · Page 45Linked to original sources
PubMed1987

[Regression of mitral valve prolapse to a state masquerading as dilated cardiomyopathy: a case report].

A 40-year-old man was admitted to our hospital in May 1982 for evaluation of a heart murmur. A standard 12-lead electrocardiogram (ECG) showed an abnormal Q wave in lead III. Echocardiography revealed prolapse of the anterior mitral valve leaflet (MVP), but neither dilatation nor wall motion abnormalities of the left ventricle (LV) were observed. Thallium-201 scintigraphy revealed an abnormal thallium uptake at the apex and inferior wall. He had no episode of acute myocardial infarction or myocarditis, but complete right bundle branch block suddenly appeared, and he was hospitalized in October 1984. He had no coronary artery lesions, and only mild mitral regurgitation on left ventriculography. The motion of the interventricular septum and apex was reduced on echocardiography and a persistent perfusion defect was observed at the inferior wall and the interventricular septum on T1-201 scintigraphy. In December 1985, he experienced an Adams-Stokes attack due to complete atrioventricular block. Echocardiographically, the left ventricle became enlarged and the wall motion abnormality and a perfusion defect on T1-201 scintigrams were of relatively severe degree. Thus, left ventricular dilatation and wall motion abnormality may progress in some cases of MVP as it did in this one. We consider this case a very interesting one in speculating on the relationship between MVP and DCM.

Adult↗
PubMed1987

[Antitumor activity of new derivatives of camptothecin].

With the purpose of obtaining more potent and less toxic camptothecin (CPT) analogs, we prepared many derivatives of CPT. Among them, 7-ethyl-CPT (SN 22) and 7-ethyl-10-hydroxy-CPT (SN 38) showed strong antitumor activity with less toxicity. They were, however, insoluble and when they were made soluble, their activity was markedly diminished, as a result of cleavage of the delta-lactone ring. We therefore attempted to make soluble derivatives without breaking the delta-lactone ring and obtained 7-ethyl-10-[4-(1-piperidino)-1-piperidino]-carbonyloxy-CPT (CPT-11), which showed very strong antitumor activity by i.p., i.v. or p.o. administration against the ascites type of L1210 leukemia, P388 leukemia, sarcoma 180, Meth A fibrosarcoma, B16 melanoma, Ehrlich carcinoma and MH134 hepatoma and the solid type of sarcoma 180, Meth A fibrosarcoma, Lewis lung carcinoma, C3H/HeN mammary carcinoma, Ehrlich carcinoma and MH134 hepatoma. The antileukemic activity of CPT-11 against L1210 was much higher than that of adriamycin. The acute toxicity of CPT-11 was extremely low, particularly in the case of oral administration, the LD50 being 765.3 mg/kg, 22 times greater than that of CPT-Na.

Animals↗
PubMed1987

Mouse anti-benzylpenicilloyl IgE monoclonal antibody: preparation, characterization and cross-reactivity.

Anti-benzylpenicilloyl (BPO-) monoclonal antibody of the IgE class was prepared from spleens of immune C57BL/6 mice whose sera reacted with BPO-hapten, penicillin G(PCG) polymer, cephalothin (CET)-hapten and CET polymer. Affinity chromatography experiments showed that the haptenic specificity of the IgE monoclonal antibody (designated BIE-13CE) was directed mainly to phenylacetyl portion of BPO group. BIE-13CE antibody reacted on passive cutaneous anaphylaxis (PCA) assay with BPO-hapten, CET-hapten, cephaloridine-hapten and CET polymer, but did not react with PCG polymer, ampicillin-hapten, or cefazolin-hapten. These results indicated that the sera of the immune C57BL/6 mice contained IgE antibodies capable of cross-reacting at the monoclonal antibody level with various forms of eliciting antigens and that the cross-reactivity of the antibody could be ascribed essentially to the structural similarity of acyl side chains of the antibiotics. The structure of the CET polymer is also discussed in terms of its PCA reactivity with the monoclonal antibody and analytical and spectral data of the polymer.

Animals↗
PubMed1987

Microscopic fluorometric analysis of Na-fluorescein transport in the smallest secretory unit (couplet hepatocytes) and the effects of cytochalasin B.

The uptake and secretion of sodium fluorescein by couplet hepatocytes was examined in primary culture. When sodium fluorescein was added at an early stage of primary couplet hepatocytes culture, this resulted in a rapid uptake of the dye and its subsequent accumulation in bile canaliculi. From microscopic fluorometry observations, cytochalasin B pretreatment of the couplet hepatocytes caused much more rapid uptake and secretion of the dye in bile canaliculi. The present study indicates that the cholestatic agent cytochalasin B causes choleresis at the bile canalicular level of cultured couplet hepatocytes and also indicates that a defect in canalicular secretion plays no role in the cytochalasin B-induced impairment of bile flow.

Animals↗
PubMed1986

Specificities of extracellular and ribosomal serine proteinases from Bacillus natto, a food microorganism.

The specificities of extracellular and ribosomal serine proteinase from Bacillus natto, a food microorganism, were investigated. Both proteins have highly restricted and characteristic specificities. With the extracellular serine proteinase, initial cleavage site was observed at Leu15-Tyr16, secondary site at Ser9-His10 and additional cleavage sites at Gln4-His5 and His5-Leu6 in the oxidized insulin B-chain. Hydrolysis of proangiotensin with the extracellular serine proteinase was observed primarily at Phe8-His9 and secondary at Tyr4-Ile5. The extracellular serine proteinase has a Km of 0.08 mM and kcat of 3 S-1 for angiotensin hydrolysis. With the ribosomal proteinase, initial cleavage site of the oxidized insulin B-chain was observed at Leu15-Tyr16 and additional cleavage site at Phe24-Phe25. Hydrolysis of proangiotensin was observed at Tyr4-Ile5 bond with the ribosomal proteinase.

Angiotensinogen↗
PubMed1986

The synthesis of metallothionein-like protein containing zinc in liver of rat after administration of calcium and calcitonin.

Subcutaneous (s.c.) and intraperitoneal (i.p.) injection and oral administration of calcium (Ca) into rats increased Ca content of liver compared with control rats. When liver cytosol was filtered through a Sephadex G-75 column, zinc (Zn) content of metallothionein (MT)-like protein fraction was several times higher in Ca treatment than in control. Zn and copper (Cu) content of high-molecular (HM) and moderate-molecular (MM) fractions and Cu content of MT fraction was unaffected by Ca treatment. Zn in MT fraction showed two peaks in the direct-connection method of high-performance liquid chromatography to atomic absorption spectrophotometer (AAS). The retention time of these two peaks agreed with those of Zn or cadmium (Cd) in MT fraction of liver cytosol obtained from Zn- or Cd-administered rat. These results show that MT-like protein containing Zn is induced by Ca. In conditions showing a slight increase in liver Ca and a significant decrease in serum Ca by synthetic [Asu1,7] eel calcitonin (CT) injection, gel filtration of liver cytosol obtained from CT-treated rats showed a higher content of Zn and a higher radioactivity of [3H]cystine than that from control injection. This suggests that CT causes an increase in liver Ca and results in induction of MT-like protein containing Zn by Ca.

Administration, Oral↗
PubMed1986

Crystal-matrix interrelations in brushite and uric acid calculi.

Brushite and uric acid calculi were studied by means of scanning electron microscopy with the partial dissolution method and transmission electron microscopy. Brushite calculi consist of radially oriented columnar crystals which have sheet-like substructure. The organic matrix is identified chiefly at the outside of the crystals but partly included between the substructure. The concentric matrix bands are often dislocated between the neighbouring crystals. Uric acid calculi also consist of radially oriented columnar crystals, and a fine meshwork of the organic matrix is incorporated within the crystals. The concentric matrix layers of different density are angled according to the crystal lattice. These findings indicate that the organic matrix arose from a mucinous surface coat, at least in the radially striated calculi. The crystals continued to grow in this gel-state milieu, either thrusting the matrix aside or incorporating it within the crystals.

Calcium Oxalate↗
PubMed1986

Familial flexion-supination deformity at the PIP joint of the finger.

The case of a 36-year-old female typist with familial bilateral flexion-supination deformity at the PIP joint of the long fingers is presented. This deformity was ascribed to hypoplasia of the radial lateral band and retaining structures of the long extensor tendon. The deformity was corrected by bridging the second dorsal interosseous muscle and the radial extensor lateral band with a free tendon graft and the reconstruction of retaining ligaments.

Adult↗
PubMed1986

Purification and properties of glucoside 3-dehydrogenase from Flavobacterium saccharophilum.

A membrane-bound glucoside 3-dehydrogenase [EC 1.1.99.13], which oxidizes validoxylamine A to the 3-keto derivative, was solubilized from the membrane fraction of Flavobacterium saccharophilum by Triton X-100 and purified about 280-fold with an overall yield of 30% from the membrane fraction by column chromatography on DEAE- and CM-Sepharose CL-6B and gel filtration on Sephacryl S-300. The purified enzyme exhibited a single protein band on disc gel electrophoresis, and FAD was shown to be the prosthetic group. The enzyme had a molecular weight of 270,000 as determined by gel filtration on Sephacryl S-300 and consisted of 4 identical subunits each with a molecular weight of 66,000. The enzyme reacted with various artificial electron acceptors such as 2,6-dichlorophenolindophenol (DCIP), phenazine methosulfate, and ferricyanide. The optimum pH for DCIP reductase activity was 6.0. The enzyme was inhibited by Hg2+ and p-chloromercuribenzoate. D-Glucose and methyl-alpha- and beta-D-glucoside showed the highest susceptibility to the enzyme, and were converted to the corresponding 3-keto sugars.

Carbohydrate Dehydrogenases↗
PubMed1986

Chemical modification by diethylpyrocarbonate of an essential histidine residue in 3-ketovalidoxylamine A C-N lyase.

3-Ketovalidoxylamine A C-N lyase of Flavobacterium saccharophilum is a monomeric protein with a molecular weight of 36,000. Amino acid analysis revealed that the enzyme contains 5 histidine residues and no cysteine residue. The enzyme was inactivated by diethylpyrocarbonate (DEP) following pseudo-first order kinetics. Upon treatment of the inactivated enzyme with hydroxylamine, the enzyme activity was completely restored. The difference absorption spectrum of the modified versus native enzyme exhibited a prominent peak around 240 nm, but there was no absorbance change above 270 nm. The pH-dependence of inactivation suggested the involvement of an amino acid residue having a pKa of 6.8. These results indicate that the inactivation is due to the modification of histidine residues. Substrates of the lyase, p-nitrophenyl-3-ketovalidamine, p-nitrophenyl-alpha-D-3-ketoglucoside, and methyl-alpha-D-3-ketoglucoside, protected the enzyme against the inactivation, suggesting that the modification occurred at or near the active site. Although several histidine residues were modified by DEP, a plot of log (reciprocal of the half-time of inactivation) versus log (concentration of DEP) suggested that one histidine residue has an essential role in catalysis.

Amino Acids↗