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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 991 records · Page 55Linked to original sources
PubMed1987

[Fundamental and clinical studies on cefuzonam in the field of obstetrics and gynecology].

Fundamental and clinical studies on cefuzonam (CZON, L-105), a new oxime type cephalosporin, were performed and the results obtained are summarized below: 1. Concentrations of CZON were determined in serum, internal genital organs and retroperitoneal fluid after a single intravenous administration of 1 g dose. The peripheral serum level of CZON was 74.0 micrograms/ml at 15 minutes after the administration. A sufficient transfer of CZON into internal genital organs and retroperitoneal fluid was demonstrated. 2. In clinical trial, CZON was given to 11 cases with obstetrical and gynecological infections. Efficacies were evaluated as good in 9 cases and poor in 2 cases. No side effects were observed in any of the cases treated with CZON. In laboratory examinations, transient elevation of serum GOT, GPT and alkaline phosphatase was noted in 1 case.

Adult↗
PubMed1986

Anchimeric assistance in the intramolecular reaction of glucose-dehydrogenase-polyethylene glycol NAD conjugate.

Polyethylene glycol-bound derivatives of NAD(P) (PEG-NAD(P)) are water-soluble macromolecular coenzymes used in continuous enzyme reactors. These NAD(P) derivatives have good coenzyme activity for many dehydrogenases, but some enzymes such as glucose dehydrogenase (EC 1.1.1.47) show very low activity with these derivatives (less than 0.1% of that for native NAD(P)). In this work, we prepared a covalently linked glucose-dehydrogenase-polyethylene glycol-NAD conjugate (GlcDH-PEG-NAD) and found that the conjugate shows a much higher reaction rate than that of the native enzyme plus PEG-NAD: the ratio of the reaction rates of GlcDH-PEG-NAD and the native enzyme plus PEG-NAD is calculated to be 10,000-fold at the concentrations of the enzyme subunit and NAD moiety of 0.31 and 0.65 microM, respectively; the rate of the conjugate is even higher than that of the native enzyme plus native NAD. This rate acceleration is due to the increase in the effective concentration of NAD moiety ("anchimeric assistance") and demonstrates the potential of covalent linking for improving the interaction between an enzyme and a coenzyme derivative.

Bacillus megaterium↗
PubMed1986

Alternative complement pathway activation by C4b deposited during classical pathway activation.

Sheep erythrocytes (E) sensitized with anti-E antibody (A) were reacted with guinea pig C1 (C1gp) and human C4 (C4hu) or guinea pig C4 (C4gp) to prepare EAC1, 4b. Treatment of the EAC1, 4b with a buffer containing EDTA removes C1rgp and C1sgp, resulting in the formation of EAC4b. EAC4b prepared in this way were found to be lysed by human or guinea pig serum in a gelatin Veronal-buffered saline containing 2 mM MgCl2 and 8 mM EGTA (Mg-EGTA-GVB). In the hemolytic sensitivity of EAC4bhu, essentially no difference was noted whether IgG or IgM antibodies were used for preparation of EAC4bhu. The extent of the hemolysis of EAC4bhu was dependent on the dose of C4bhu. Because EAC4bhu were lysed even by C2-deficient human serum, C3 convertase of the classical complement pathway would not be involved in the hemolysis of EAC4bhu. Furthermore, the reactivity of EAC4bhu with serum in Mg-EGTA-GVB remained even after treatment of the intermediate cells with 1 mM PMSF, indicating that any remaining C1gp was not responsible for the hemolysis. Therefore, the hemolysis of EAC4b by sera in Mg-EGTA-GVB was considered to be mediated via activation of the alternative complement pathway (ACP). Pretreatment of EAC4bhu with anti-C4hu antibody or C4-binding protein suppressed the hemolysis of EAC4bhu via the ACP activation. Furthermore, EAC4bhu were more sensitive to hemolysis by the reaction with a mixture of C3, B, D, and H followed by rat serum in EDTA-GVB than EAC1qgp were. These results indicate that C4b molecules on the cell membrane participate in the activation of ACP.

Animals↗
PubMed1986

Covalent linking of poly(ethyleneglycol)-bound NAD with Thermus thermophilus malate dehydrogenase. NAD(H)-regeneration unit for a coupled second-enzyme reaction.

Poly(ethyleneglycol)-bound NAD (PEG-NAD) was covalently linked to Thermus thermophilus malate dehydrogenase with a bifunctional reagent, 3,3'-(1,6-dioxo-1,6-hexanediyl)bis-2-thiazolidinethione. The covalently linked malate-dehydrogenase--PEG--NAD complex (MDH-PEG-NAD) was purified by DEAE-Sephadex column chromatography to remove unbound PEG-NAD, and fractionated by blue-Sepharose column chromatography into four preparations: MDH-PEG-NAD I, MDH-PEG-NAD II, MDH-PEG-NAD III and MDH-PEG-NAD IV. The average numbers of NAD moieties covalently bound per subunit of MDH-PEG-NAD I, MDH-PEG-NAD II, MDH-PEG-NAD III and MDH-PEG-NAD IV were 1.2, 1.2, 0.8 and 0.5, respectively, and the values were confirmed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. 60-80% bound NAD moiety of these preparations of MDH-PEG-NAD was reduced by the enzyme moiety in the presence of L-malate, and the specific activity of the enzyme moiety of the preparations was more than 80% that of the native enzyme. MDH-PEG-NAD I has the following properties. The Km value for exogenous NAD is three times that of the native enzyme. The coenzyme activity of its NAD moiety is 20-40% that of native NAD for alcohol and lactate dehydrogenases. The complex catalyzes the oxidation of L-malate in the presence of the redox system of 5-ethylphenazinium ethyl sulfate and a tetrazolium salt with a rate constant of 0.11 s-1. The coenzyme moiety of the complex can also be recycled by coupled reactions of the active site of the same complex and alcohol dehydrogenase. These results indicate that MDH-PEG-NAD works as an NAD(H)-regeneration unit for coupled reactions.

Coenzymes↗
PubMed1986

[Aromatization of androstenedione and 19-nortestosterone in human placenta, liver and adipose tissues].

Aromatization of C-19-steroid (androstenedione; delta 4 A) and C-19 norsteroid (19-nortestosterone; NT) was measured in human placenta, liver and adipose tissues. The tissue homogenates (0.5 approximately 1.0 g w.w.) were incubated with [6, 7-3H]-delta 4 A or [6, 7-3H]-NT (10 microCi) and NADPH (1 mg/ml of 0.1M-bisodium phosphate buffer) at 37 degrees C for 2 hr in air. The enzyme reaction was terminated with 3 volumes of ethyl acetate, and [4-14C]-estrone (E1) and [4-14C]-estradiol-17 beta (E2) (10,000 dpm, 250 micrograms) were added in the incubated sample. The extract with ethyl acetate was subjected to Bio-Rad AG1-X2 column chromatography. The phenol fraction thus obtained was subjected to thin layer chromatography (TLC) (cyclohexane-ethyl acetate = 2:1, V/V and chloroform-ethyl ether = 4:1, V/V). The resulting E1 and E2 were finally isolated by co-crystallization to constant specific activity and 3H/14C ratio of crystal crops. In human placental microsomes, estrogen formation from delta 4 A and NT was 8.10 and 1.84 pmol E1 + E2/hr/mg protein, respectively. In adult liver homogenates, only E1 (35-76 fmol/hr/g) was formed from delta 4 A, but E1 and E2 were formed (70 and 31-61 fmol/hr/g, respectively) from NT. On the other hand, adipose tissue had the ability to aromatize delta 4 A to E1 (38-69 fmol/hr/g), but its ability to aromatize NT was significantly lower than that for delta 4 A. These results show that NT is readily aromatized to estrogens in the liver.

Adipose Tissue↗
PubMed1986

Purification of peroxisomal malate synthase from alkane-grown Candida tropicalis and some properties of the purified enzyme.

Malate synthase, one of the key enzymes in the glyoxylate cycle, was purified from peroxisomes of alkane-grown yeast, Candida tropicalis. The enzyme was mainly localized in the matrix of peroxisomes, judging from subcellular fractionation followed by exposure of the organelles to hypotonic conditions. The molecular mass of this peroxisomal malate synthase was determined to be 250,000 daltons by gel filtration on a Sepharose 6B column as well as by ultracentrifugation. On sodium dodecylsulfate/polyacrylamide slab-gel electrophoresis, the molecular mass of the subunit of the enzyme was demonstrated to be 61,000 daltons. These results revealed that the native form of this enzyme was homo-tetrameric. Peroxisomal malate synthase showed the optimal activity pH at 8.0 and absolutely required Mg2+ for enzymatic activity. The Km values for Mg2+, acetyl-CoA and glyoxylate were 4.7 mM, 80 microM and 1.0 mM, respectively.

Alkanes↗
PubMed1986

Enhanced production of gamma-interferon by therapy with parenteral OK-432 and alpha-interferon in patients with head and neck cancer.

Although the drug OK-432 can induce the release of gamma-interferon (IFN-gamma), the serum concentrations of IFN-gamma produced are very low. We studied the effects of combining OK-432 with alpha-interferon (IFN-alpha) on the endogenous production of IFN and the postoperative courses of patients with oral cavity cancers. Forty patients operated on for head and neck cancers were studied. Each patient was given an injection of OK-432 1 week after surgery. Between 10 and 14 days later, a combination of OK-432 and IFN-alpha was given to assess the effects of the concomitant use of IFN-alpha on IFN production. In 18 of the 30 patients given a large dose of IFN-alpha (3 or 5 X 10(6) IU/mg protein), IFN production induced by OK-432 was enhanced. A small dose of IFN-alpha (7 X 10(3) IU) did not enhance the action of OK-432. OK-432 also induced the release of both endogenous IFN-gamma and IFN-alpha, and the production of both types of IFN was enhanced by the concomitant administration of parenteral IFN-alpha. Next, 50 patients operated on for oral cavity cancers were given OK-432 or a combination of OK-432 and IFN-alpha for 4 months, and their postoperative courses were followed for 2-5 years. The clinical courses were better in the combined therapy group than in the group given OK-432 alone.

Biological Products↗
PubMed1986

Huge intraabdominal fibromatosis on the posterior wall of uterus: a case report.

A patient with a huge intraabdominal fibromatosis connected by a pedicle to the posterior wall of the uterus is described. The blood supply to the tumor was exclusively from the uterus. CA 125 antigen in the patient's serum was elevated. The origin of the tumor is unknown but possibly from non-specific fibrous stroma in the uterus or peritoneum. We measured steroid receptors in the tumor and related tissues (peritoneum and cultured peritoneal fibroblasts), for information on steroid activity.

Adult↗
PubMed1986

Structure of a beta-galactosidase gene of Bacillus stearothermophilus.

The nucleotide sequence of the bgaB gene, which encodes the thermostable beta-galactosidase I of Bacillus stearothermophilus, and its flanking region was determined. A 2,016-base-pair open reading frame observed was concluded to be for beta-galactosidase I (Mr 78,051) from observations that the amino acid composition of the enzyme and the sequence of 14 amino acids from the amino-terminus of the enzyme coincided with those deduced from this open frame. A 107-base-pair HaeIII-AluI fragment just upstream of the estimated Shine-Dalgarno sequence of the bgaB gene had promoter activity toward cat-86 (chloramphenicol acetyltransferase gene) and produced the enzyme at a level equivalent to 7% of the total cellular protein of B. subtilis. From the base sequence of this DNA region and the transcriptional start site determined by S1 nuclease mapping, the -35 and -10 sequences are estimated to be TTGACA and TAATTT, respectively, which are similar to the consensus sequence of B. subtilis sigma 43 RNA polymerase.

Amino Acid Sequence↗