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Biomedical subjects

H Toda

Publications and source records attributed to H Toda.

At least 163 records · Page 9Linked to original sources
PubMed1989

[Anesthesia for Shy-Drager syndrome; effects of elastic bandage, phenylephrine, and IPPV].

A 57-year-old man with Shy-Drager syndrome underwent plastic surgery for decubitus on the buttocks under general anesthesia. Before induction of anesthesia, an elastic bandage was applied to the legs, and its effects were examined by raising the upper body. The fall in mean blood pressure decreased from 49% to 39%, and the symptoms of cerebral hypoxia disappeared. However, the induction of anesthesia with 5 mg diazepam, 0.05 mg fentanyl, and 100 mg thiamylal reduced blood pressure abruptly from 150/88 mmHg to 95/68 mmHg. Continuous infusion of phenylephrine was then started, and blood pressure became stable at around 150/90 mmHg. In this state, IPPV did not reduce the blood pressure in the supine position, and did not intensify its fall when the upper body was raised. Anesthesia was maintained with nitrous oxide 70% in oxygen, fentanyl and pancuronium. During the surgery, ventilation was controlled, and phenylephrine was infused at the rate of 5-15 micrograms.min-1 to maintain systolic blood pressure above 100 mmHg. Phenylephrine was infused during the two postoperative days, because blood pressure fell whenever the patient's posture was changed to prevent pressure on the operative site.

Anesthesia↗
PubMed1988

The amino acid sequence of the 24-kDa subunit, an iron-sulfur protein, of rat liver mitochondrial NADH dehydrogenase deduced from cDNA sequence.

Antiserum directed against bovine heart mitochondrial NADH dehydrogenase has been used to screen a rat liver cDNA expression library in lambda gt11. The insert cDNA of a positive clone was found to represent the 24-kDa subunit of NADH dehydrogenase by epitope selection using nitrocellulose filter containing the expressed proteins. The amino acid sequence deduced from the nucleotide sequence of the cloned cDNA indicated that the 24-kDa subunit is produced as a precursor with an amino-terminal extension, and that its mature form consists of 217 amino acid residues with a molecular weight of 23,933.

Amino Acid Sequence↗
PubMed1988

Cloning and sequencing of a cDNA for human mitochondrial ubiquinone-binding protein of complex III.

The ubiquinone-binding protein (QP-C) is a nuclear-encoded component of ubiquinol-cytochrome c oxidoreductase in the mitochondrial respiratory chain and plays an important role in electron transfer as a ubiquinone-QP-C complex. We obtained a partial cDNA for rat liver QP-C by screening a lambda gt11 rat liver cDNA library using antiserum directed against bovine heart QP-C. Using this cDNA as a probe, a cDNA clone was isolated from a human fibroblast cDNA library by colony hybridization. The total length of the cloned cDNA was 518 base pairs with an open reading frame of 333 base pairs. The 111-amino acid sequence deduced from the nucleotide sequence of the cDNA is 85% homologous to that of bovine QP-C and contains only a single additional amino-terminal methionine. This implies that the human QP-C is synthesized without a presequence which is required for import of most nuclear-encoded mitochondrial proteins into mitochondria.

Amino Acid Sequence↗
PubMed1988

Bile acid binding and hypocholesterolemic activity of a new anion exchange resin from 2-methylimidazol and epichlorohydrin.

A new anion exchange resin with an imidazolium salt on a epoxide polymer skeleton was synthesized. This white powder material was odorless and tasteless. The in vitro sodium cholate binding of this resin was much more potent than that of cholestyramine. The hypocholesterolemic activity of this resin in cholesterol-fed rabbits proved to be 4.3 times more potent than that of cholestyramine. These results suggest that effective reduction of plasma cholesterol may be achieved with lower doses of this resin.

Animals↗
PubMed1988

[Microbiological evaluation of topical application of the controlled release strips containing ofloxacin (PT-01) in the human periodontal pocket].

The recognition that destructive periodontal diseases may be caused by specific microorganisms has led to an increased interest and usage of antimicrobial agents in periodontal therapy. In this study, the effect of topical application of ofloxacin (OFLX), a synthetic antibiotic, was microbiologically evaluated. The new developed controlled release strips containing OFLX (PT-01), in which there were structurally immediate- and sustained-releasing portions, were applied to the periodontal pockets of 27 adult subjects with periodontitis. Three different sites with a deep probing pocket depth (greater than or equal to 5 mm) were randomly selected in each patient, and were divided into three groups, i.e., PT-01 applied site (T), placebo-applied site (P) and control site (C). Periodontal treatments consisted of oral hygiene instruction and supragingival scaling on day 0 and 7, and subgingival scaling and root planing on day 14. PT-01 was weekly applied on day 0 to 35, and the subgingival plaque samples from each site were collected on day 0, 14, 21 and 42. The dynamics of subgingival microflora was investigated by dark field microscopy for determination of the %s of spirochetes, motile rods and coccoid cells, and anaerobic and aerobic cultivations for the determinations of the total number of subgingival bacteria, black-pigmented Bacteroides (BPB), Fusobacterium species and Actinobacillus actinomycetemcomitans. The results showed that the significant reduction of %s of spirochetes and motile rods and significant increase of % coccoid cells were found in only PT-01 applied sites during first 14 days. In this period, the total number of cultivable bacteria, BPB and Fusobacterium species were also significantly reduced in T sites. While, after subgingival scaling and root planing were performed, significant changes in the proportions and numbers of the subgingival microflora were found in all sites. Especially, PT-01 applied site showed significant improvement in the %s of spirochetes and motile rods as well as the total number of the bacteria. Moreover, the further microbiological determinations of the each isolate revealed that no detectable amounts of A. actinomycetemcomitans could be found from any samples in this study. These results suggested that weekly application of PT-01 in the periodontal pocket could have significant effects on the qualitative and quantitative improvements in the subgingival microflora. It was also suggested that the application of PT-01 might have ameliorating effect as adjuncts of mechanical subgingival plaque control in the periodontal treatment.

Adult↗
PubMed1987

Hypothermia enhances acetylcholine-induced contraction of isolated rat ileum.

The amplitude of acetylcholine (ACh)-induced contraction of isolated rat ileum was enhanced at medium temperatures lower than normal body temperature. Maximum enhancement was achieved between 30 and 25 degrees C. Changes in medium pH and activities of the enteric nervous system due to temperature changes were not essential for this enhancement.

Acetylcholine↗
PubMed1987

Electrophysiological mechanisms for the initiation and maintenance of ventricular fibrillation in nonischemic rabbit hearts.

Two series of experiments were carried out using isolated, perfused rabbit hearts to elucidate the mechanisms of initiation and maintenance of ventricular fibrillation in the absence of ischemia. In the first series, either single premature or rapid electrical stimulation induced ventricular fibrillation, during which the spread of excitation was studied by recording electrograms from the endocardial and epicardial surfaces of both ventricles. Left ventricular endocardial stimulation appeared to induce fibrillation most easily. Initiation of ventricular fibrillation was preceded by the spread of areas showing a conduction delay. In certain instances, excitation of the endocardial and subendocardial tissue was necessary for the maintenance of repetitive responses. Injury to the endocardial and subendocardial layers of a ventricle (or both ventricles) by formaldehyde perfusion made the initiation of fibrillation more difficult, although complete prevention of fibrillation required extensive injury with a significant reduction in the excitable myocardial mass. In the second series of experiments, sustained ventricular fibrillation was produced by rapid electrical stimulation and the effects of several antiarrhythmic agents or electrolytes were studied by recording transmembrane action potentials of subepicardial ventricular muscle fibers with microelectrodes. Quinidine, lidocaine, and high K+ concentration significantly decreased the frequency of cellular depolarization and terminated fibrillation in all the 14 hearts studied. These agents suppressed local responses and small action potentials, and made the action potentials more uniform. In 5 of the 14 hearts in these three groups, termination of fibrillation was followed by either transient or prolonged periods of regular ventricular tachycardia. High Mg2+ concentration and bretylium tosylate tended to hyperpolarize the cell membrane, but less markedly decreased the frequency of cellular discharge. Defibrillation was achieved in only two of the ten hearts in which these two interventions were tested. Lanatoside C shortened the action potential duration, sometimes increased the frequency of cellular depolarization, and tended to sustain fibrillatory movements. These observations suggest the role of numerous microreentry movements in both the initiation and maintenance of ventricular fibrillation, although unifocal, ectopic impulse formation may not be definitely ruled out as an initiating mechanism. The possible defibrillating effect of certain antiarrhythmic agents is suggested.

Animals↗
PubMed1986

Characterization of structural unit of phospholamban by amino acid sequencing and electrophoretic analysis.

The partial amino acid sequence of phospholamban from canine cardiac sarcoplasmic reticulum was determined by sequence analysis of the peptides obtained from the protein cleaved by cyanogen bromide and with TPCK-trypsin. The sequence determined initiated with N alpha-acetylated methionine followed by 44 amino acid residues intervening two unidentified residues. This polypeptide would represent a structural unit (protomer) of phospholamban. Analysis of temperature-dependent conversion of phospholamban from 26 kDa to lower molecular weight form (6 kDa) suggested that phospholamban holoprotein is composed of five identical protomers.

Amino Acid Sequence↗
PubMed1986

Separation and identification of two native forms of spinach ferredoxin by hydrophobic chromatography.

Hydrophobic chromatography on a TSK-gel Phenyl-5PW column separated highly purified spinach ferredoxin into two distinct molecular species in their native forms. The two ferredoxins showed almost the same absorption spectra in spite of a difference in amino acid composition. Both ferredoxins were active in the NADPH-cytochrome c reducing system, and no significant difference was observed between their activities. The new separation method was also applied to ferredoxins highly purified from wheat plants and barley. Interestingly, all ferredoxin preparations so far examined contained two molecular species of ferredoxin.

Amino Acids↗
PubMed1985

Comparative study on amino acid sequences of Kunitz-type soybean trypsin inhibitors, Tia, Tib, and Tic.

The amino acid sequences of three variants of the Kunitz-type trypsin inhibitors, Tia, Tib, and Tic, obtained from some cultivars of soybean were determined by conventional methods. All three inhibitors consisted of 181 amino acid residues. The differences in the amino acid sequences are as follows: Tia E12 G55 Y62 H71 S74 M114 L120 P137 L176; Tib S F N R V I T V; Tic E. The amino acid sequences of Pro(60)-Ser(61) and Asp(154)-Asp(155)-Gly(156)-His(157) of Tia reported previously (Koide & Ikenaka (1973) Eur. J. Biochem. 32, 417-431) were amended to Ser(60)-Pro(61) and His(154)-Asp-Asp-Gly(157), respectively.

Amino Acid Sequence↗