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Biomedical subjects

T Ohshiro

Publications and source records attributed to T Ohshiro.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Pharmacological study of 5'-DFUR oral administration and the clinical responses against gastrointestinal carcinoma].

In 4 out of 5 patients given 400 mg orally 5'-DFUR before surgery, intratumor 5-FU concentration showed over 150 ng/g. The concentration of either 5-FU or 5'-DFUR in the portal and peripheral blood of these patients exceeded the limits of assay. 5-FU concentration in peripheral blood was less than 0.05 micrograms/ml. White blood cell and platelet counts in the patients given 1,600 mg/day (no administration for 2 days/week) of 5'-DFUR for one month were essentially the same with those at the time of start of the treatment. Two of three patients showed minor response following the treatment with 5'-DFUR. Thus, administration of 1,600 mg/day of 5'-DFUR may be considered as an effective treatment of fluopyrimidine against advanced cancer. For the prediction of gastrointestinal side effect, assay of the 5-FU concentration in the portal blood seemed to be useful.

Administration, Oral↗
PubMed1994

Cloning and expression of the gene for hydroxypyruvate reductase (D-glycerate dehydrogenase from an obligate methylotroph Hyphomicrobium methylovorum GM2.

The gene encoding hydroxypyruvate reductase, catalyzing the asymmetric reduction of hydroxypyruvate to D-glycerate, and its flanking regions were isolated from a methylotrophic bacterium, Hyphomicrobium methylovorum GM2. Nucleotide sequencing of the recombinant plasmids revealed that the hydroxypyruvate-reductase gene codes for the 322-amino-acid protein with calculated molecular mass 35,726 Da. The sequence was confirmed by sequencing the intact enzyme and peptides obtained by digestion of the enzyme with Achromobacter proteinase I. The amino acid sequence of the enzyme showed similarity to members of the D-isomer-specific 2-hydroxyacid dehydrogenase family. The recombinant plasmid, which was constructed by ligation of the cloned gene and an expression vector pKK223-3, was introduced into Escherichia coli HB101. The recombinant enzyme purified from the transformed E. coli cells was indistinguishable from the enzyme isolated from H. methylovorum GM2 by immunological and enzymological analyses.

Alcohol Oxidoreductases↗
PubMed1994

Selective Desulfurization of Dibenzothiophene by Rhodococcus erythropolis D-1.

A dibenzothiophene (DBT)-degrading bacterium, Rhodococcus erythropolis D-1, which utilized DBT as a sole source of sulfur, was isolated from soil. DBT was metabolized to 2-hydroxybiphenyl (2-HBP) by the strain, and 2-HBP was almost stoichiometrically accumulated as the dead-end metabolite of DBT degradation. DBT degradation by this strain was shown to proceed as DBT --> DBT sulfone --> 2-HBP. DBT at an initial concentration of 0.125 mM was completely degraded within 2 days of cultivation. DBT at up to 2.2 mM was rapidly degraded by resting cells within only 150 min. It was thought this strain had a higher DBT-desulfurizing ability than other microorganisms reported previously.

Journal Article↗
PubMed1994

Enzymatic conversion of dethiobiotin to biotin in cell-free extracts of a Bacillus sphaericus bioB transformant.

The activity of biotin synthase, responsible for biotin synthesis from dethiobiotin, was demonstrated in a completely defined reaction mixture with cell-free extracts of a Bacillus sphaericus bioB transformant. Among the sulfur compounds tested, only S-adenosyl-L-methionine was active, while L-methionine and L-cysteine had no significant effect. Protein concentrations higher than 15 mg/ml in the reaction mixture were needed to detect biotin synthase activity. When dialyzed cell-free extracts were used for the reaction, NADH, NADPH, or FAD among the well-known cofactors tested enhanced the activity, and Fe2+, Mn2+, and Ca2+ among the metal ions tested also had some effects.

Bacillus↗
PubMed1994

On the mechanism of biotin synthase of Bacillus sphaericus.

A cell-free system of a bioB transformant of Bacillus sphaericus, effecting the last step of biotin biosynthesis, namely the introduction of sulfur into dethiobiotin has been recently described. S-adenosyl methionine (SAM) is absolutely necessary for activity. We show here, through experiments with [35S]SAM and [35S]Cys, that the sulfur donor is not SAM but probably cysteine (Cys) or a derivative. This finding together with the fact that NADPH and FAD are required for activity leads us to postulate some analogy between the biotin synthase system and other systems which use SAM as a source of desoxyadenosyl radical.

Bacillus↗
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

Laser applications in plastic and reconstructive surgery.

Very shortly after the laser's first successful firing in 1960, applications were found in the medical field in the specialities of ophthalmology and dermatology and have since expanded to include indications in plastic and reconstructive surgery. In the photodestructive mode, laser energy is used selectively to vaporize, incise, excise, ablade and coagulate target tissue; the surgical laser can also degrade or denature protein in the target tissue, and the latter photoreaction now forms the basis for laser tissue welding in a variety of tissue types. The author refers to these photodestructive applications as high reactive-level laser treatment, or HLLT. In laser therapeutic applications, the temperature of the cells may rise only very slightly or not at all, and there is no immediate irreversible change in the target tissue architecture. The level of reaction is thus lower than the cell survival threshold, giving a direct photoactivative effect. The author refers to this as low reactive-level laser therapy, or LLLT: LLLT applications include pain attenuation, wound healing acceleration; enhanced remodeling in accelerated bone and tendon repair; restoration of normal neural function; normalization of abnormal hormonal function; modulation of the autoimmune system; control of hyper- and hypotension and so on. HLLT and LLLT are contrasted and compared, and applications of both HLLT and LLLT in PRS are discussed in brief.

Humans↗
PubMed1993

[Statistical observations on the cases of unnatural deaths examined at our department during the past 10 years].

Medicolegal evaluation of 1495 cases of unnatural death of last 10 years was carried out in our department and the data so obtained were statistically analysed. The cases consisted of 260 inspections, 865 judicial autopsies and 370 administrative autopsies. The most frequent category was death from diseases followed by suicide, homicide, traffic accidents, other accidents and self originated accidents. In homicide cases, sharp objects were mainly used. Six cases of accident of scuba diving were included within the group of 28 cases of drowning of self originated variety. Although Okinawa is subtropical 12 cases of death by accidental hypothermia were found. Gangland fight using rifles cost 7 lives, 2 policemen, a high school student and 4 members of locally originated gangsters during last 18 months. Cardiac insufficiency was the most common of sudden unexpected death cases that complied with the data of Tokyo and Osaka. Death from alimentary disorder in Okinawa was 1.5 times more frequent than that in Tokyo and Osaka and liver disorder accounted for about 41%. The 68 cases of death from suckling contained 10 SIDS cases. Complication of medical treatment was encountered in 9 cases during the past 10 years.

Adolescent↗
PubMed1992

Optimum culture conditions for the epoxidation of cis-propenylphosphonate to fosfomycin by Cellvibrio gilvus.

Approximately 470 strains of various microorganisms were tested for their ability to epoxidize cis-propenylphosphonate (PPOH) to (-)-cis-1,2-epoxypropylphosphonate (fosfomycin, FOM). Cellvibrio gilvus KY 3412 was selected as the best strain. To obtain higher activity, FOM-resistant strains were derived by N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. Mutant KY 3413, showing ten times higher FOM resistance, was selected. The conditions for the conversion of PPOH to FOM during the cultivation of the mutant were optimized. The addition of both cobalt and vanadium ions to the culture medium greatly stimulated the conversion. Furthermore, when the pH was maintained at pH 8.0 during cultivation, the highest conversion was attained. The molar conversion yield of FOM was inversely dependent on the initial concentration of PPOH, that is, conversions of 100% at less than 0.05% PPOH and of 40% at 0.5% PPOH were attained after 5 days cultivation.

Cobalt↗
PubMed1992

Production of dihydrofolate reductase by cloned Escherichia coli and its application to asymmetric synthesis of l-leucovorin.

We have investigated culture conditions for production of dihydrofolate reductase by Escherichia coli harboring a high expression plasmid, pTP64-1. Sorbitol addition and pH control were effective for the production of the enzyme in a jar fermentor. The enzyme was purified from a cell-free extract by column chromatographies on DEAE-Cellulofine and Superose Prep12 and showed a single band on SDS-polyacrylamide gel electrophoresis. The reduction of 200 mM dihydrofolate to 6(S)-tetrahydrofolate, an intermediate for l-leucovorin synthesis, was complete in 2 hr under anaerobic conditions, using 1.5 units/ml of the purified enzyme.

Chromatography, DEAE-Cellulose↗
PubMed1991

Development of low reactive-level laser therapy and its present status.

A new subspecialty in the medical application of the laser has developed, especially over the last decade, depending on the therapeutic rather than the surgical applications of the laser. Laser therapy, or preferably, Low reactive-Level Laser Therapy (LLLT) is now being recognized as a valid medical tool. Two types of LLLT are presented, simultaneous and pure. In surgical laser applications, ranges of heat are generated in the target tissue, destroying or altering its architecture. This is referred to as high reactive-level laser treatment, or HLLT. In addition, nonphotothermally destructive reactions may also occur, such as photo-osmosis. These are also part of HLLT. Simultaneously, nondestructive thermal and nonthermal bioactivation occur at the periphery of the target tissue: this is "simultaneous LLLT" and occurs along with HLLT, explaining some of the advantages of laser surgery. Laser systems have been developed which deliver power and energy densities below the destructive level, only to activate the irradiated tissue. This is "pure LLLT." The history and background of LLLT are presented, the terminology discussed, and practical applications of LLLT are presented.

Female↗
PubMed1990

[Flavonoid constituents of Melicope triphylla MERR.II].

From the leaves of Melicope triphylla MERR., three new flavonoids (1-3) were isolated, together with nine known flavonoids, 4',5-dihydroxy-3,3',7- trimethoxyflavone (4), 5-hydroxy-3,3',4',7-tetramethoxyflavone (5), 3,3',4',5,7-pentamethoxyflavone (6), 7-hydroxy-3,3',4',5,8-pentamethoxyflavone (7), 3,3',4',5,7,8-hexamethoxyflavone (8), 5-hydroxy-3,7,8-trimethoxy-3',4'-methylenedioxyflavone (9), 7-hydroxy-3,5,8- trimethoxy-3',4'-methylenedioxyflavone (10), 3,5,7,8-tetramethoxy-3',4'-methylenedioxyflavone (11), and 5-hydroxy- 3,6,7,8-tetramethoxy-3',4'-methylenedioxyflavone (12). The structures of 1, 2, and 3 were established as 5-hydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone, 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3',4'-methylenedioxyfl avone, and 4'-hydroxy-7-isopentenyloxy-3,3',5,8-tetramethoxyflavone by their respective chemical and spectral data. The 20 flavonoids isolated from this plant were examined for the piscicidal activities.

Animals↗
PubMed1990

Appraisal of myocutaneous flapping for treatment of postmastectomy lymphedema. Case report.

Two patients with severe postmastectomy lymphedema of the upper extremity were treated with myocutaneous flapping, using latissimus dorsi muscle. Complete disappearance of edema was achieved by 11 months postoperatively in one case and 50% reduction by 8 months in the other case. The satisfactory results commend the procedure, which has yet to gain global acceptance.

Aged↗
PubMed1990

Morphological studies of bradykinin-treatments on the rat trigeminal sensory neuron.

Subcutaneous injections of bradykinin to the rat trigeminal region over 4 days produced a significant increase in the number of mitochondria in the small trigeminal ganglion cells and the central terminals of unmyelinated fibers in the spinal trigeminal nucleus. In the large trigeminal ganglion cells, no significant change in the number of mitochondria was observed. These results seem to demonstrate that bradykinin stimulates unmyelinated nerve and increases its energy consumption.

Animals↗
PubMed1989

Metabolism of liposome-encapsulated heparin.

In order to elucidate the metabolism of liposome encapsulated heparin (LIPO-HEP), LIPO-HEP containing 3H-heparin (3H-HEP) and/or 14C-phosphatidylcholine (14C-PC) was intravenously administered into rats and the radioactivity as well as the biological activity in plasma and certain organs was investigated. The amount of 3H-radioactivity in plasma was significantly higher in rats receiving LIPO-HEP than in those receiving untreated heparin. The amount of 14C-radioactivity in plasma of rats receiving LIPO-HEP, however, was not proportional to the amount of 3H-radioactivity in the same rats, indicating the dissociation of liposome and heparin in plasma. Incorporation of 3H-radioactivity into various organs examined, i.e., liver, spleen, lung, was significantly higher in rats receiving LIPO-HEP than in those receiving untreated heparin, e.g. 4.7 and 11.8 times higher in the liver and the spleen, respectively at 150 min after the injection. Thereby, in contrast to the untreated heparin, LIPO-HEP was selectively incorporated into the reticuloendothelial system (RES) and it may be suggested that prolonged biological activity in LIPO-HEP is due to a gradual release of heparin from the liposomes entrapped in RES, and that it is not due to prolonged circulation in blood.

Animals↗
PubMed1989

Pathogenesis of early thrombus formation in experimental vein graft.

When inferior vena cava of rabbit was replaced by 3 cm long woven Tetron (polyethylene terephthalates) graft under bolus injection of heparin (50 U/kg), the graft was completely occluded at 1.5 +/- 0.35 h after the bolus injection of heparin. In order to elucidate the pathogenesis of this early thrombus formation, the same venous grafting was performed in rabbits receiving anticoagulants and/or anti-platelet agents and the thrombus formation was analyzed by scanning electron microscopy as well as by measuring the weight of dehydrated thrombus. The grafts in rabbits receiving an additional bolus heparin were patent until the anticoagulant effect disappeared and the thrombus formed in these grafts was composed of platelet aggregates anchored to synthetic fibers and of erythrocytes trapped into fibrin network. The patency of the graft was maintained at least 5 hours in rabbits receiving intravenous injection of aspirin (20 mg/kg) or oral administration of ticlopidine (100 mg/kg/day x 5 days prior to the grafting). The weight of dehydrated thrombus of the graft in aspirin and ticlopidine treated rabbits was 25 +/- 5 and 12 +/- 4 mg respectively, which were significantly lower than that of control group (59 +/- 9 mg). Ultrastructural studies revealed in these grafts piles of erythrocytes with fibrin network which were layered over the synthetic fibers without bridges of platelet aggregates. Also, the treatment with anti-platelet agents, especially ticlopidine, resulted in inhibition of organization of fibrin network. These observations indicate that thrombus in venous graft is formed by anchorage of platelet aggregates to synthetic fibers followed by activation of coagulation to form network of polymerized fibrin entrapping erythrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗