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Biomedical subjects

M Ohashi

Publications and source records attributed to M Ohashi.

At least 361 records · Page 20Linked to original sources
PubMed1987

Metabolic fate of diltiazem. Distribution, excretion and protein binding in rat and dog.

Pharmacokinetics of (+)-(2S,3S)-2,3-dihydro-3-acetoxy-2-(4-methoxyphenyl)-5- [2-(dimethylamino)ethyl]-1,5-benzothiazepin-4(5H)-one hydrochloride (diltiazem-HCl, Cardizem, Herbesser) in rats and dogs were investigated using 14C-diltiazem-HCL. The plasma concentration of unchanged drug in rats was 1.78 microgram/ml 1 min after intravenous administration at a dose of 3 mg/kg, and rapidly decreased thereafter with a half-life of 20 min (alpha-phase) and 56 min (beta-phase). In contrast, the plasma concentration of radioactivity in rats increased during 0-2 h in spite of intravenous administration, and thereafter the level of radioactivity in plasma decreased very slow. In dogs, the plasma concentration of unchanged drug was 0.138 micrograms/ml 1 min after intravenous administration at a dose of 0.2 mg/kg, and then decreased with a half-life of 2.5 min (alpha-phase) and 1.68 h (beta-phase). Dog plasma level of radioactivity decreased once after intravenous administration, but increased from 30 min to 1 h. Unchanged drug plasma levels at 1 h after intravenous administration were 6.6 and 35.1% of the plasma radioactivities in rats and dogs, respectively. When 14C-diltiazem-HCl was orally administered, unchanged drug plasma levels in rats and dogs were 1.8 and 12.8% of the plasma radioactivities at 15 min, respectively. Therefore, the first-pass effect was extensive, especially in rats. Rat whole body autoradiograms showed that radioactivity distributed well to tissues and organs in either route of administration. Similar results were obtained by the method of counting the radioactivity in the tissues and organs of rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Enzyme-linked immunodetection of proteins on Coomassie blue-stained two-dimensional cellulose acetate membranes.

Cellulose acetate membrane on which proteins are separated by two-dimensional electrophoresis and visualized by Coomassie staining is directly subjected to an enzyme-linked immunodetection method using a horseradish peroxidase-conjugated second antibody. The Coomassie-stained and immunochemically stained spots are distinguishable by their colors, such as blue with Coomassie blue staining and purple with horseradish peroxidase staining. Two kinds of lighting make the distinction more apparent. Coomassie-stained protein patterns are clear in the transmitted light. However, the immunochemically stained protein spots are obvious in the reflected light, in which Coomassie-stained patterns are obscure. The procedures do not require proteins to transfer onto nitrocellulose paper in contrast to proteins in polyacrylamide gel. The simple procedure excludes the nonspecific binding of the first and second antibodies to blocking proteins such as bovine serum albumin or gelatin because blocking protein is not used. With this method, matching of the Coomassie blue-stained spot with the immunochemically stained spot is done accurately and easily.

Animals↗
PubMed1986

Glucoside formation as a novel metabolic pathway of pantothenic acid in the dog.

Metabolism of pantothenic acid (PaA) in beagle dogs was investigated. The dogs excreted 12.3% of the dose in the urine within 24 hr after a single oral administration of [3H]PaA (3 mg/kg). High performance liquid chromatographic analysis of the urine showed the presence of unchanged vitamin and a major metabolite, which accounted for 60.2 and 39.8% of the urinary radioactivity respectively. Although the metabolite was hydrolyzed by treatment with beta-glucuronidase or acid phosphatase, it was found that this hydrolysis resulted from the actions of beta-glucosidase contained as a contaminant in these enzyme preparations. beta-Glucosidase completely hydrolyzed the metabolite to generate PaA and glucose. The metabolite was isolated and subjected to GC/MS and NMR analyses. It was identical to synthetic PaA beta-glucoside, 4'-O-(beta-D-glucopyranosyl)-D-pantothenic acid. It was shown by the use of dog liver microsomes that PaA underwent beta-glucosidation in the presence of uridine diphosphate glucose (UDPG). It is proposed that beta-glucosidation by UDP-glucosyltransferase is a novel metabolic pathway of PaA in the dog.

Animals↗
PubMed1986

Purification and identification of intermediate catabolic products in the in vivo degradation of pig liver phosphofructokinase.

Phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) was purified to homogeneity from pig livers. Polyclonal antibody against the enzyme was induced in a rabbit, and the IgG fraction was obtained by chromatography on a Protein A-Sepharose CL-4B column. The specific antibody was purified further by immunoaffinity chromatography on a phosphofructokinase-conjugated affinity column. Intermediate catabolic products of phosphofructokinase were extracted from fresh pig livers under conditions of inhibition of proteinases, concentrated by chromatography on an anti-phosphofructokinase IgG-conjugated affinity column, and purified by two-dimensional polyacrylamide gel electrophoresis. Their cross-reactivities to the purified phosphofructokinase were assessed by an immunoelectrotransfer blot method. The intact form of phosphofructokinase in pig liver was demonstrated as the major spot of 84 kDa on the blot. Polypeptides of 68, 64, 56, and 51 kDa showed apparent cross-reactivities to phosphofructokinase. The structural homology among them was confirmed by proteinase V8 digestion followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The possibility of artifacts in preparation was ruled out by an internal tracer method. Thus, it is concluded that the predominant isozyme of phosphofructokinase in pig liver (84 kDa) is in vivo degraded via intermediate catabolic products of 68, 64, 56, and 51 kDa.

Animals↗
PubMed1986

Release of calcitonin gene-related peptide from a human medullary carcinoma of the thyroid in vitro.

The secretion of human calcitonin gene-related peptide was examined in perifusates of medullary carcinoma of the thyroid with a sensitive radioreceptor assay. Calcitonin gene-related peptide was released after the addition of calcium (25-100 mM), in a dose-dependent manner. The results indicate that human medullary carcinomas of the thyroid secrete the calcitonin gene-related peptide as well as calcitonin.

Adult↗
PubMed1986

Aphidicolin-resistant mutants of bacteriophage phi 29: genetic evidence for altered DNA polymerase.

Aphidicolin-resistant mutants (Aphr) of Bacillus subtilis bacteriophage phi 29 were isolated after mutagenesis with hydroxylamine. Efficiency of plating (e.o.p.) of the resistant mutants was not reduced at 500 microM aphidicolin, although e.o.p. of wild type phi 29 was less than 10(-5) at the same concentration of aphidicolin. By recombination and complementation analyses, both sites of the mutations, aph-71 and aph-101, of Aphr71 and Aphr101, respectively, were mapped in gene 2 which encodes phi 29 DNA polymerase. The activity of wild type phi 29 DNA polymerase, in a partially purified fraction, was inhibited by aphidicolin. DNA polymerases from Aphr71 and Aphr101, prepared in the same manner as that of wild type, were resistant to the drug. These results indicate that the acquisition of the aphidicolin resistance of Aphr71 and Aphr101 of bacteriophage phi 29 results from a structural alteration of phi 29 DNA polymerase which reduces sensitivity to aphidicolin.

Aphidicolin↗
PubMed1986

Histopathology of otitis media with effusion. An electron microscopic study of human temporal bones.

Ultrastructural studies of the middle ear mucosa appear to be of significant value in better understanding the pathology of otitis media with effusion (OME). Our present study was undertaken in order to take advantage of the use of electron microscopy in investigating all areas of the middle ear mucosa. Tissues studied were obtained from the fresh postmortem temporal bones of three patients with OME and terminal head and neck malignancies. In the mucoid type of effusion (cases 1 and 2), goblet cells were seen to proliferate and secretory activity was greatly enhanced. In contrast, there was no evidence of secretory cell proliferation in the serous type of effusion. It was noteworthy that accumulated fluid was not homogeneous in the same ear, as exemplified by case 1, in which both mucoid and serous effusions were present. This occurrence was possibly the result of topographic diversity involving the secretory activity of the middle ear.

Child↗
PubMed1986

Antagonistic effect of KC-404, a new anti-asthmatic agent, on leukotriene D4-induced contractile responses in isolated guinea pig smooth muscles.

The inhibitory effects of KC-404, a novel clinically available anti-asthmatic drug, on leukotriene(LT) D4-, LTC4-, histamine- and acetylcholine(ACh)-induced contractile responses in isolated guinea pig lung parenchymal, tracheal and ileal longitudinal strips were compared using an organ bath system. In lung parenchyma, KC-404 antagonized LTD4 in a competitive fashion, whereas it antagonized histamine noncompetitively. The pA2 value against LTD4 was 7.39. KC-404 hardly antagonized LTC4 and ACh. A ranked order of potency estimated from its minimum effective concentrations (MEC) was LTD4 greater than histamine greater than LTC4 greater than ACh. In trachea, KC-404 antagonized LTC4 and LTD4 in a competitive fashion, while it antagonized histamine noncompetitively. The pA2 values against LTC4 and LTD4 were 5.99 and 6.51, respectively. KC-404 hardly antagonized ACh. A ranked order of the potency estimated from MEC was LTD4 greater than LTC4 greater than histamine greater than ACh. The pA2 values of KC-404 against LTD4 in lung parenchyma and trachea were little or not altered, while its inhibitory effect on histamine-induced contraction in trachea was markedly diminished by the pretreatment of tissues with indomethacin. In ileum, KC-404 noncompetitively antagonized all of the agonists used. A ranked order of the potency estimated from pD2 values was LTD4 divided by LTC4 greater than histamine greater than ACh. These results suggest that KC-404 is a selective antagonist of LTD4 and that it might interact with LTD4 receptor in airway smooth muscles but not in ileum. Another possibility that the drug might interact with LTD4 specific excitation-contraction coupling mechanism was also discussed.

Acetylcholine↗
PubMed1986

Lightning injury caused by discharges accompanying flashovers--a clinical and experimental study of death and survival.

During the 17 years preceding March 1985, 140 patients sustained lightning injuries caused by 44 thunderbolts. Fifty patients showed evidence of current flow through their bodies. These 50 victims were classified into two groups, the first consisting of 9 victims who showed rupture of their clothes or linear superficial dermal burns along their whole bodies from head to feet, indicating the occurrence of surface flashovers. The remaining 41 patients showed no evidence of this flash effect. It is noteworthy that in the first group 5 of the 9 survived, whereas in the second group only 6 among 41 survived. The result indicates that when a flashover occurs along the whole body, the probability of survival is higher than 50 per cent. The conditions which determine death or survival were investigated experimentally, imposing artificial lightning voltage impulses on rats and developing flashovers on them. The rats survived when the voltage drop caused by flashover occurred immediately after the peak point, and the current waveform exhibited a sharp peak. In contrast, the rats were killed when the voltage drop caused by flashover was delayed by more than 20 microseconds, and the current waveform showed a blunt cone shape. It has been concluded that a fast flashover appreciably diminishes the energy dissipation within the body and consequently results in survival.

Animals↗
PubMed1986

Anti-leukotriene D4 action of a new anti-asthmatic drug (KC-404) on the guinea-pig isolated trachea.

Anti-asthmatic drug, KC-404, inhibited specifically spontaneous contraction and leukotriene (LT) D4-induced contraction of guinea-pig trachea. Relaxation of spontaneous contraction by KC-404 was reduced by the treatment of the guinea-pig trachea with a cyclooxygenase inhibitor, flurbiprofen. Some parallel shift of the concentration-action curve of LTD4 by KC-404 was still observed in the presence of flurbiprofen. Specific binding of [3H]LTD4 to the microsomal fraction of guinea-pig trachea was partially inhibited by KC-404. These results suggest that the relaxing action of trachea of KC-404 is due to the interference of interaction between LTD4 and its receptor and to the product(s) via cyclooxygenase pathway.

Animals↗
PubMed1986

Influence of indomethacin on an increase in cerebral blood flow induced by KC-404, a novel cerebral vasodilator, in an anesthetized dog.

The effect of KC-404 on vertebral blood flow in the absence and presence of indomethacin was investigated in an anesthetized dog. KC-404 (0.2 mg/kg, i.v.) showed a significant and long lasting increase in vertebral blood flow. This was markedly diminished by pretreatment of the animal with indomethacin. The increase in heart rate due to KC-404 administration was also diminished, though moderately, by pretreatment with indomethacin. From these results, the possible mechanism of action of KC-404 was discussed, particularly in reference to cerebral vasodilating prostaglandins.

Animals↗
PubMed1986

Anti-thrombotic effect of KC-404, a novel cerebral vasodilator.

KC-404 prevented mice from death and rats from A-V block, both induced by rapid i.v. injection of adenosine diphosphate (ADP), at high doses (5-100 mg/kg, i.v.). KC-404, at relatively lower doses (0.5-2 mg/kg, i.v.), inhibited the electroencephalographic (EEG) change in rat rapidly administered with arachidonic acid (AA) into the internal carotid artery. KC-404 (0.3-3 mg/kg, p.o.) inhibited the necrotic change of lower leg, paw or finger of rat when injected with sodium laurate into the femoral artery. KC-404 at doses up to 100 mg/kg, p.o. did not alter bleeding time in rat. Thus, KC-404 is expected to be of therapeutic value in cerebrovascular disorders accompanying thrombus in cerebral vasculature.

Adenosine Diphosphate↗