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Biomedical subjects

Y Wachi

Publications and source records attributed to Y Wachi.

7 recordsLinked to original sources
PubMed1997

[A survival case of intraoperative pulmonary embolism diagnosed early by transesophageal echocardiography].

An otherwise healthy 36-year-old housewife was diagnosed with advanced cancer of the stomach 5 months after her third parturition. Surgery was performed with the patient under total intravenous anesthesia combined with continuous epidural anesthesia. The course of anesthesia and the operative course were uneventful until the abdominal skin was sutured, when unexplained severe circulatory collapse developed. A widely dissociated PETCO2- PaCO2 suggested pulmonary embolism, and the findings of transesophageal echocardiography corroborated the diagnosis. Infusion of 480,000 units of urokinase in 30 minutes was immediately started via a Swan-Ganz catheter, and intravenous heparin 10,000 units in 24 hours, was administrated continuously. The pulmonary circulation was restored 30 minutes after the start of therapy, resulting in rapid recovery of the patient's systemic circulatory and acid-base status. The patient was safely extubated 19 hours postoperatively.

Adult↗
PubMed1996

[Anesthetic management of 6 cases with dilated cardiomyopathy for non-cardiac surgery].

We report anesthetic management of 6 cases (5 patients) with dilated cardiomyopathy for noncardiac surgery. The severity of their cardiomyopathy evaluated by left ventricular ejection fraction (LVEF) utilizing echocardiography was different in each case. The management of anesthesia was divided into 3 steps according to the LVEF. In cases with LVEF over 0.45, it was possible to perform regular anesthetic management by carefully selecting and controlling anesthetic agents. In 2 cases with LVEF from 0.2 to 0.4, anesthetic management was difficult. Some vasoactive drugs (e.g. dopamine) and intensive monitoring devices (e.g. pulmonary artery catheter) were needed to optimize anesthetic course. In one case with LVEF less than 0.2, we discussed much about surgical indication. Because of the malignant nature of the tumor, we agreed to proceed. IABP was inserted preoperatively and this proved to be life-saving during the procedure. It is important to have an inter-departmental discussion on these severely compromised cases.

Adult↗
PubMed1995

Effect of ultraviolet-A (UV-A) light on growth, photosynthetic activity and production of biopterin glucoside by the marine UV-A resistant cyanobacterium Oscillatoria sp.

We have isolated a marine planktonic cyanobacterium Oscillatoria sp. NKBG 091600 which is resistant to ultraviolet-A (UV-A) irradiation. In response to UV-A irradiation this cyanobacterium produces high levels of a UV-A absorbing compound which was identified previously as biopterin glucoside. Here, we have investigated the effect of UV-A light intensity on growth, biopterin glucoside production and photosynthetic activity. Oscillatoria sp. NKBG 091600 could grow at UV-A intensities of up to 800 microW/cm2 and at 300 microW/cm2 could grow as well as in the absence of UV-A irradiation. In addition, pre-culture of cells with UV-A protected cells from UV-A induced inhibition of photosynthetic activity. Detection of biopterin glucoside levels in irradiated cells by HPLC demonstrated that after 10 h there was a rapid increase in biopterin glucoside content. This increase was dependent on the intensity on the intensity of the UV-A irradiation.

Biopterins↗
PubMed1995

Molecular analysis of growth inhibition caused by overexpression of the biotin operon in Escherichia coli.

Constitutive overexpression of the biotin operon (type 9 mutation) in a multicopy plasmid resulted in growth inhibition in Escherichia coli. Deletion analysis of the biotin operon indicated that overexpression of the bioB gene alone, the product of which is believed to catalyze the conversion of dethiobiotin to biotin, is sufficient for growth inhibition. This growth inhibition was still observed when the wild-type bioB gene was replaced by several mutant-type bioB genes derived from biotin auxotrophs that have base-pair substitutions creating amino acid substitutions in the bioB gene product. However, the modification of Ala 143 and Gly 99 of the bioB gene product resulted in recovery from growth inhibition. These results suggest that this phenotype of growth inhibition by overexpression of the bioB gene in E. coli is independent of the biotin-forming activity itself, but is caused by some function involving a specific conformation of the bioB gene product.

Amino Acid Sequence↗
PubMed1994

Flavodoxin is required for conversion of dethiobiotin to biotin in Escherichia coli.

We have reported [Ifuku, O., Kishimoto, J., Haze, S., Yanagi, M. & Fukushima, S. (1992) Biosci. Biotechnol. Biochem. 56, 1780-1785] the enzymic conversion of dethiobiotin to biotin (catalyzed by the enzyme encoded by bioB) in cell-free extract of Escherichia coli which had been genetically engineered for high bioB expression. An unidentified protein(s) in addition to the bioB gene product is obligatory for this reaction. We have found that this protein was precipitated from the cell-free extract with poly(ethyleneimine), and we have purified it to homogeneity by a procedure which includes ammonium sulfate fractionation, DEAE-cellulose chromatography, gel filtration, and Mono Q chromatography. The apparent molecular mass of the purified protein was estimated to be about 21 kDa by SDS/PAGE. The N-terminal amino acid sequence of the purified protein was identical with that of E. coli flavodoxin. We conclude that flavodoxin is required for conversion of dethiobiotin to biotin in E. coli. Studies with purified flavodoxin and the fraction containing the bioB gene product suggested that protein(s) in addition to the bioB gene product and flavodoxin is also obligatory for the reaction.

Amino Acid Sequence↗
PubMed1994

Origin of carbon atoms of biotin. 13C-NMR studies on biotin biosynthesis in Escherichia coli.

The origin of the carbon atoms of pimeloyl-CoA, the earliest known precursor in the pathway of de novo biotin biosynthesis in Escherichia coli, was investigated by 13C-NMR spectroscopy. In fermentation of the biotin-overproducing DRK332/pXBA312 strain of Escherichia coli (a repressor mutant carrying a biotin operon fragment in the plasmid), a high dose of L-alanine (8 g/l) stimulated dethiobiotin and biotin accumulation. Although L-alanine is a known precursor of 7-keto-8-aminopelargonic acid in biotin biosynthesis, the 13C-NMR spectrum of dethiobiotin showed that the C-3 of L-[3-13C]alanine was incorporated into not only the methyl carbon (C-9) but also alternate carbons (C-2, C-4, C-6) of the side chain, and these latter positions are the same as those labeled with D-[1-13C]glucose. These data indicate that L-alanine can act as an alternative carbon source, suggesting that acetyl-CoA is a possible precursor for pimeloyl-CoA synthesis. In accordance with this hypothesis, the C-1 of sodium (1-13C)acetate and the C-2 of sodium (2-13C)acetate were incorporated into alternate carbons in the side chain of dethiobiotin, i.e., (C-1, C-3, C-5, C-7) and (C-1, C-2, C-4, C-6), respectively. These results suggested firstly that in E. coli pimeloyl-CoA is biosynthesized from L-alanine and/or acetate via acetyl-CoA, but not via pimelic acid, which has been suggested as a biotin precursor in other species, and secondly that the carboxyl group of biotin originates from carbon dioxide produced through the tricarboxylic acid cycle.

Acetates↗