Biomedical subjects

A Miyata

Publications and source records attributed to A Miyata.

At least 127 records · Page 7Linked to original sources

PubMed1994

Superficial esophageal carcinoma: evaluation by endoscopic ultrasonography.

OBJECTIVES: The aim of this study was to evaluate the usefulness of endoscopic ultrasonography (EUS) in the staging of superficial esophageal carcinoma (SEC). METHODS: We examined the histopathologic findings of 28 patients with SEC which was confirmed in the postoperative histologic evaluation. The EUS results preoperatively estimated were compared with them. RESULTS: There were nine patients with mucosal carcinoma (two intraepithelial carcinomas and seven carcinomas limited to the mucosal layer) and 19 patients with submucosal carcinoma. The mucosal carcinomas revealed no lymph node metastasis or vessel permeation, whereas the submucosal carcinomas revealed lymph node metastasis (71%) and vessel permeation (lymphatic, 58%, vascular, 21%). The accuracy rates of depth of invasion by EUS were mucosa, 67% (6/9); submucosa, 79% (15/19); and total, 75% (21/28). EUS could not detect microinvasion to the submucosa. The overall accuracy rate of EUS in the evaluation of periesophagogastric lymph node metastasis was 72%: sensitivity 58% and specificity 85%. CONCLUSIONS: It has been clinically proved important to differentiate mucosal carcinoma from submucosal carcinoma in the staging of SEC, and EUS is recommended in differentiating between them.

Adult↗

PubMed1993

Primary structure of alpha-tocopherol transfer protein from rat liver. Homology with cellular retinaldehyde-binding protein.

alpha-Tocopherol transfer protein (alpha TTP) present in rat liver cytosol specifically binds this vitamin and enhances its transfer between separate membranes. We previously reported purification of alpha TTP and showed that two isoforms exist in rat liver, of which the isoelectric points are 5.0 and 5.1, respectively (Sato, Y., Hagiwara, K., Arai, H., and Inoue, K. (1991) FEBS Lett. 288, 41-45). In the present paper, we have isolated a cDNA clone with 2194 base pairs encoding alpha TTP from a rat liver cDNA library. The amino acid sequence deduced from the cDNA contained all the sequences of the peptide fragments obtained by digestion of the purified protein with endoproteinase Lys-C. The isolated cDNA was found to encode the isoform with a pI of 5.0 on the basis of the cross-reactivity of the recombinant protein expressed in Escherichia coli with the isoform-specific monoclonal antibody. From the longest open reading frame of the cloned cDNA, one isoform of rat liver alpha TTP is predicted to be composed of 278 amino acid residues of calculated molecular weight 31,845. Both Western and Northern blot analyses revealed that alpha TTP is expressed exclusively in the liver in rats. alpha TTP has been found to exhibit a structural homology with the cellular retinaldehyde-binding protein present only in visual tissues.

Amino Acid Sequence↗

PubMed1993

Molecular cloning and expression of the gene for serine hydroxymethyltransferase from an obligate methylotroph Hyphomicrobium methylovorum GM2.

The gene encoding serine hydroxymethyltransferase (SHMT), one of the key enzymes of the one-carbon-compound assimilation of a methylotroph, Hyphomicrobium methylovorum GM2, and its flanking regions were isolated using a DNA fragment encoding Escherichia coli SHMT as a probe. Nucleotide sequencing of the recombinant plasmids revealed the SHMT gene codes for the 434-amino-acid protein with a calculated molecular mass of 46,068 Da. The amino-acid sequence of the enzyme showed identity to the sequences of the enzymes from E. coli (55%) and rabbit liver (44%). The recombinant plasmid, which was constructed by ligation of the cloned gene and an expression vector pKK223-3, was introduced to an SHMT-deficient E. coli mutant ME5427 (glyA-). The transformed E. coli cells expressed SHMT, which was immunologically and enzymologically indistinguishable from the enzyme isolated from H. methylovorum GM2.

Amino Acid Sequence↗

PubMed1993

Expression of human thromboxane synthase using a baculovirus system.

Human thromboxane (TX) synthase (EC 5.3.99.5) was produced by the baculovirus expression system using cDNA encoding human TX synthase [(1991) Biochem. Biophys. Res. Commun. 78, 1479-1484]. A recombinant baculovirus TXS7 was expressed in Spodoptera frugiperda Sf9 insect cells. The expressed protein was recognized by monoclonal antibody, Kon 7 raised against human TX synthase [(1990) Blood 76, 80-85]. The recombinant TX synthase catalyzed the conversion of prostaglandin (PG) H2 to TXA2 and 12-hydroxy-heptadecatrienoic acid (HHT). Both conversions of PGH2 to TXA2 and HHT by the expressed TX synthase were completely inhibited by a specific TX synthase inhibitor, OKY-046 (5 microM).

Animals↗

PubMed1993

Endomitotic diploidization of Saccharomyces cerevisiae by heat treatment during spore germination.

Diploid cells with ability to mate, hereafter referred to as diploid mater cells, were obtained at significant frequencies by the heat treatment of haploid spores at the early germination stage in Saccharomyces cerevisiae heterothallic strain CG5M (a/alpha diploid cells heterozygous for five auxotrophic markers). The highest frequency (ca. 11%) of diploidization was obtained from viable cells after heat treatment at 55 degrees C for 10 min when spores were precultivated for 30 min in liquid medium to initiate the germination. The diploid mater cells obtained were homozygous for mating type and for the auxotrophic markers. The diploidization of a spore is thus concluded to be due to endomitotic events in germinating heat-treated spores.

Diploidy↗

PubMed1993

L-serine production by a methylotroph and its related enzymes.

The production process of L-serine from methanol and glycine has been developed using a methylotroph with the serine pathway. Consecutive reactions of two enzymes, methanol dehydrogenase (MDH) and serine hydroxymethyltransferase (SHMT) are involved in the production. We screened a high producer, Hyphomicrobium methylovorum, which is an obligate methylotroph. With resting cells of the bacterium, 24 mg/ml of L-serine was produced from 100 mg/ml of glycine and 48 mg/ml of methanol in 3 days under optimal conditions. Next, a glycine-resistant mutant GM2 showed improved serine production (32-34 mg/ml). The mutant GM2 was found to have elevated activities of MDH and SHMT. Since there has so far been little report on the systematic characterization of enzymes of the serine pathway in methylotrophs, not only the above two enzymes but also the other three enzymes in H. methylovorum were purified and characterized: MDH, SHMT and hydroxypyruvate reductase (HPR) were crystallized; serine-glyoxylate aminotransferase (SGAT) and glycerate kinase (GK) were purified to homogeneity. As a result, all these enzymes were found to be stable against preservation and to exist abundantly in the bacterium. The gene of SHMT was cloned and its deduced amino acid sequence had homology to those of Escherichia coli (55%) and rabbit liver (44%), whereas the enzyme of the bacterium was immunochemically distinguishable from those of microorganisms other than Hyphomicrobium strains and mammalian livers.

Alcohol Oxidoreductases↗

PubMed1993

Effect of short-term administration of dexamethasone on canine antral gastrin gene expression.

The acute effect of corticosteroids on the release and biosynthesis of gastrin still remains unclear. We report the effect of short-term administration of dexamethasone on the antral gastrin gene expression and gastrin levels in 6 dogs, which were treated with dexamethasone (1.5 mg/kg, i.m. daily) for 3 days. One day after treatment, gastrin mRNA levels increased (152 +/- 14%), but serum and tissue gastrin showed no significant changes. With 2 and 3 days of dexamethasone treatment, gastrin mRNA (2 days: 163 +/- 28%, 3 days: 170 +/- 22%), serum gastrin (2 days: from 94 +/- 12 to 168 +/- 23 pg/ml, 3 days: to 180 +/- 16 pg/ml) and tissue gastrin concentration (2 days: from 480 +/- 32 to 664 +/- 31 pg/mg tissue protein, 3 days: to 708 +/- 45 pg/mg tissue protein) significantly increased. However, gastrin mRNA levels were not increased even after 1 day culture of canine antral tissue with dexamethasone in vitro. These findings suggest that short-term administration of corticosteroid may increase the canine gastrin gene expression in vivo by an unknown pathway.

Animals↗

PubMed1993

An unusual morphological type of Trypanosoma (Herpetosoma) lewisi (Kent, 1880) detected in the blood of Rattus norvegicus in India.

An unusual morphological type of Trypanosoma (Herpetosoma) lewisi (Kent, 1880) which was detected in Rattus norvegicus in India is reported in the present study. This type is different from known types of T. lewisi in that the kinetoplast is at a greater distance from the posterior end (P-K) than the usual type. The total length, including the free flagellum, is 35.3-39.3 microns and P-K is 11.9-15.0 as against total length of 21 to 36.5 microns in the normal form.

Animals↗

PubMed1993

[Intensive care of a postpartum patient complicated with HELLP syndrome].

We reported our intensive care experience of a postpartum patient with HELLP syndrome. We administered haptoglobin immediately after the delivery in order to prevent renal insufficiency following hemoglobinuria. Continuous veno-venous hemofiltration was undertaken and plasma exchange was also employed to overcome hepatorenal insufficiency. After these procedures an improvement was observed in her hepatic and renal functions. Administration of haptoglobin and blood purification would be beneficial for patients complicated with HELLP syndrome.

Adult↗

PubMed1993

[A case report of total intravenous anesthesia for renal transplantation].

A 20-year-old female patient with chronic renal failure received renal transplantation under total intravenous anesthesia with droperidol, fentanyl and ketamine. Anesthesia was induced with droperidol 12.5 mg, fentanyl 100 micrograms, ketamine 100 mg and vecuronium bromide 5 mg, and maintained with fentanyl and ketamine. Ketamine was given continuously at a rate of 2.0 mg.kg-1.h-1. After the renal artery and vein of the donor kidney were anastomosed with the patient's internal iliac artery and vein, the urine output of 7.7 ml.min-1 was obtained. The patient recovered from anesthesia smoothly and her postoperative course was uneventful. Although plasma epinephrine, cortisol and ADH levels showed significant changes during anesthesia mainly due to surgical stress, they returned to normal values after the end of operation. We conclude that this method of anesthesia would be a choice for renal transplantation.

Adult↗

PubMed1992

Identification of calcitonin gene related peptide in ovine hypothalamic extract.

Calcitonin gene-related polypeptide (CGRP) was purified from ovine hypothalamic extracts. Its amino acid sequence was determined as: Ser-(Cys)-Asn-Thr-Ala-Thr-(Cys)-Val-Thr-His-Arg-Leu-Ala-Gly-Leu-Leu-Ser- Arg-Ser - Gly-Gly-Val-Val-Lys-Ser-Asn-Phe-Val-Pro-Thr-Asn-Val-Gly-Ser-Gln-Ala-Phe- NH2. This sequence differs from rat CGRP by two amino acid substitutions (Ser for Asp25 and Gln for Glu35). Adenylate cyclase stimulating activity in rat pituitary cell cultures was monitored during the isolation. CGRP had adenylate cyclase stimulating activity comparable to corticotropin-releasing hormone, suggesting a hypophysiotropic role for CGRP. This is the first chemical characterization of CGRP in the brain (hypothalamus).

Amino Acid Sequence↗

PubMed1992

Induction of thromboxane synthase and prostaglandin endoperoxide synthase mRNAs in human erythroleukemia cells by phorbol ester.

The effects of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the mRNA levels of two enzymes, thromboxane synthase (TXS) and prostaglandin endoperoxide synthase (PES), responsible for the synthesis of thromboxane A2 from arachidonic acid, were studied in human erythroleukemia (HEL) cells by RNA blot analysis. TPA induced both TXS and PES mRNAs in HEL cells in a dose-dependent manner at 36 h. The half-maximal and maximal effects for the induction of both mRNAs were at approximately 3 x 10(-9) M and at 10(-8) M, respectively. TXS and PES mRNA levels increased in a time-dependent fashion by TPA, and reached to 7- and 3.5-fold of the control, respectively after 48 h of TPA treatment. These results suggest that expression of TXS and PES genes in HEL cells were simultaneously stimulated by TPA.

Cyclooxygenase Inhibitors↗

PubMed1992

Chemical characterization of vasoactive intestinal polypeptide-like immunoreactivity in ovine hypothalamus and intestine.

Two forms of pituitary adenylate cyclase activating polypeptides with 38 (PACAP38) and 27 residues (PACAP27) respectively were recently isolated from ovine hypothalamic tissues. The N-terminal 28 amino acids sequence of PACAP was found to have 68% homology with porcine vasoactive intestinal peptide (VIP). In order to determine whether the primary structure of VIP of ovine hypothalamus is identical with porcine VIP or similar to PACAP, VIP immunoreactivity as determined by radioimmunoassay for porcine VIP was isolated in a pure form from ovine hypothalamic extracts. VIP was also isolated from ovine intestine. Amino acid analysis as well as amino acid sequence analysis showed that ovine hypothalamic and intestinal VIP were identical to porcine VIP, but different from PACAP.

Adenylyl Cyclases↗

PubMed1992

Immunoaffinity purification and cDNA cloning of human platelet prostaglandin endoperoxide synthase (cyclooxygenase).

The cDNA for prostaglandin endoperoxide synthase (cyclooxygenase) was cloned from human platelets by the polymerase chain reaction amplification method, and the primary structure of the enzyme was deduced from the nucleotide sequence. The enzyme was composed of 599 amino acids including 23-amino acid signal sequence, and the calculated molecular weight of the mature protein was 65,995. The enzyme was immunoaffinity-purified from human platelets. The N-terminal amino acid sequence determined by Edman degradation was Ala-Asp-Pro-Gly-Ala-Pro-Thr-Pro-, and the result confirmed the primary structure of the enzyme, which was deduced from the cDNA sequence.

Acetylation↗

PubMed1992

Ruptured cerebral aneurysm associated with coarctation of the aorta--report of two cases.

Two cases of ruptured cerebral aneurysm associated with coarctation of the aorta are presented. The aneurysms were successfully clipped in the acute stage prior to correction of the coarctation. Ruptured aneurysm should be treated as early as possible, and unruptured aneurysm should also be treated before aortic repair, if the general condition of the patient allows.

Adolescent↗

PubMed1992

[Electrophysiologic effect of a new Ca(2+)-antagonist, TA-3090 on supraventricular tachycardia and conduction system].

We investigated the effect of a new Ca-antagonist, TA-3090 on supraventricular tachycardia (SVT) and conduction system, comparing it with the effect of Diltiazem Hydrochloride, in 11 patients who had paroxysmal SVT attacks. Seven of the 11 patients presented atrioventricular reentrant tachycardia (AVRT) via retrograde concealed conduction through an accessory pathway, and the others presented AV nodal reentrant tachycardia (AVNRT). After SVT was induced by means of programmed electrical stimulation at high right atrium, TA-3090 (0.1 mg/kg body weight) or Diltiazem (0.2 mg/kg) was administered intravenously for 3 minutes. TA-3090 terminated nine of 11 SVTs, while Diltiazem terminated four of 4 SVTs. On termination of SVT, both drugs interrupted A-H conduction during AVRT and the slow pathway during AVNRT. After TA injection, five of 11 SVTs could not be induced by programmed electrical stimulation, while two of 4 SVTs could not be induced after Diltiazem. In AVRT, three patients in which TA-3090 prevented SVT induction had a longer AV node effective refractory period than that of the others in which TA-3090 could not prevent SVT (330 +/- 46 vs 210 +/- 24 msec, p less than 0.01). However, SVT was induced more easily than before in three of the 11 patients treated with TA-3090 administration, and in one of the 4 patients treated with Diltiazem administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Molecular cloning of human platelet thromboxane A synthase.

Complementary DNA coding for thromboxane A synthase was amplified by polymerase chain reaction using primers synthesized according to the partial amino acid sequences of human platelet thromboxane A synthase (Nüsing, R., Schneider-Voss, S., and Ullrich, V. (1990) Arch. Biochem. Biophys. 280, 325-330) and cloned into pBluescript SK II(-). The primary structure of human platelet enzyme was deduced from the nucleotide sequence of the cDNA. The enzyme is composed of 533 amino acids with a molecular weight of 60,487. The primary structure of the enzyme exhibited a 34-36% homology to the amino acid sequences of cytochrome P450s classified in the P450 III gene family. The highly conserved cysteine-containing sequence involved in the heme-binding site of P450 was found near the carboxyl terminus (residues 472-492). The size of the major thromboxane A synthase mRNA from human platelets and human erythroleukemia cells was estimated to be approximately 2.2 kilobases by RNA blot analysis.

Amino Acid Sequence↗

PubMed1991

In-vitro and in-vivo antimicrobial activities of a novel cephalosporin derivative, CP6162, possessing a dihydroxypyridone moiety at the C-3 side chain.

The antibacterial activity of a novel cephalosporin derivative, CP6162, possessing a dihydroxypyridone moiety at the C-3 side chain, was evaluated in vitro and in vivo, with ceftazidime, aztreonam and cefoperazone as the reference antibiotics. CP6162 showed weak or little activity against Gram-positive bacteria, but potent activity against clinical isolates of the Gram-negative species including strains of Pseudomonas aeruginosa, Ps. cepacia, Acinetobacter sp., Xanthomonas maltophilia, Serratia marcescens, Enterobacter cloacae and Citrobacter freundii, which were resistant to the reference antibiotics. The MICs of CP6162 were only slightly affected by the high producers of beta-lactamases except for cephalosporinase-producing C. freundii. It was, however, affected by the presence of ferric ion. CP6162 showed in-vivo activity paralleling the in-vitro activity, and also showed pharmacokinetic parameters similar to those of ceftazidime in mice and rats.

Animals↗