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Biomedical subjects

T Shibata

Publications and source records attributed to T Shibata.

At least 1,081 records · Page 60Linked to original sources
PubMed1981

Pre- and postoperative arrhythmias in congenital heart disease: from the results of surgery using surface-induced deep hypothermia.

The incidence of arrhythmias in 3614 preoperative patients with congenital heart disease was 1.6 per cent. Pre- and postoperative serial ECGs in 186 patients with an isolated VSD and in 58 patients with TOF were reviewed. The incidence of CRBBB and CRBBB-LAH following VSD repair was 33% and 6.6%, respectively, and for TOF was 55% and 5.2%, respectively. Complete A-V block (CAVB) was seen in 2 patients following VSD repair, and none of TOF patients developed CAVB. Late cardiac or dysrrhythmic death was not recognized in our limited follow up period. The indications for surgery in membranous VSD should be determined more carefully, because the risk of the surgical damage to the conduction system is still higher. Moreover, we must keep in mind that damage to the A-V conduction system may occur naturally even in a patient with small VSD. Finally, it can never be overemphasized that physicians must pay attention to the occurrence and course of postoperative arrhythmias.

Adolescent↗
PubMed1981

Chirally selective synthesis of sugar moiety of nucleosides by chemicoenzymatic approach: L- and D-riboses, showdomycin, and cordycepin.

The symmetric dimethyl esters derived from furan and dimethyl acetylenedicarboxylate was efficiently hydrolysed with pig liver esterase to yield half esters with high optical purity. Following chemical transformations afforded precursors with L-configuration, and chirality transfer through ester exchange was achieved to afford precursors with D-configuration of the sugar moiety of nucleosides. Thus, an efficient approach to L- and D-riboses, showdomycin, and cordycepin (3'-deoxy-adenosine) has been demonstrated.U

Animals↗
PubMed1980

Analgesic action of intrathecal and intracerebral beta-endorphin in rats: comparison with morphine.

beta-Endorphin and morphine were given into the nucleus reticularis gigantocellularis (NRGC), spinal subarachnoid space and third ventricle of rats, and the antinociceptive effects were assessed by the tail-pinch method. The NRGC was 4-5 times as sensitive to beta-endorphin as was the spinal subarachnoid space and third ventricle, while the NRGC was 13-19 times as sensitive to morphine as were the other regions. Thus, it would appear that beta-endorphin has more sites of action for the production of analgesia than does morphine.

Analgesics↗
PubMed1980

Simultaneous determination of phenylbutazone and its metabolites in plasma and urine by high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for the simultaneous determination of phenylbutazone and its metabolites, oxyphenbutazone and gamma-hydroxy-phenylbutazone, in plasma and urine. Samples were acidified with hydrochloric acid and extracted with benzene--cyclohexane (1:1, v/v). The extract was redissolved in methanol and chromatographed on a muBondapak C18 column using a mobile phase of methanol--0.01 M sodium acetate buffer (pH 4.0) in a linear gradient (50 to 100% methanol at 5% min; flow-rate 2.0 ml/min) in a high-performance liquid chromatograph equipped with an ultraviolet absorbance detector (254 nm). The detection limit for phenylbutazone, oxyphenbutazone and for gamma-hydroxyphenylbutazone was 0.05 microgram/ml. A precise and sensitive assay for the determination of phenylbutazone and its metabolites was established.

Animals↗
PubMed1980

Simultaneous high-performance liquid chromatographic determination of suxibuzone and its metabolites in plasma and urine.

A high-performance liquid chromatographic method is described for the simultaneous determination of the anti-inflammatory agent suxibuzone and its metabolites, 4-hydroxymethylphenylbutazone, phenylbutazone, oxyphenbutazone, and gamma-hydroxyphenylbutazone, in plasma and urine. Acidified plasma or urine is extracted with benzenecyclohexane (1:1). The organic extract is reduced to dryness and the resulting residue is redissolved in methanol. Aliquots of this solution are chromatographed on a reversed-phase column using a mobile phase of methanol--0.5 M KH2PO4 (linear gradient from 0 to 100% methanol at 8% min with a flow rate of 2.0 ml/min) on a high-performance liquid chromatograph equipped with a UV absorbance detector (254 nm). Detection is limited to 0.10 microgram/ml for suxibuzone and 4-hydroxymethylphenylbutazone and to 0.05 microgram/ml for the other metabolites.

Anti-Inflammatory Agents↗
PubMed1980

Homologous pairing in genetic recombination: recA protein makes joint molecules of gapped circular DNA and closed circular DNA.

The recA protein, which is essential for genetic recombination in E. coli, promotes the homologous pairing of double-stranded DNA and linear single-stranded DNA, thereby forming a three-stranded joint molecule called a D loop. Single-stranded DNA stimulates recA protein to unwind double-stranded DNA. By a presumably related mechanism, recA protein promoted the homologous pairing of two circular double-stranded molecules when one of them has a gap in one strand. The two molecules were joined at homologous sites by noncovalent bonds. The covalently closed molecule remained intact and was not topologically linked to the intact circular strand of the gapped substrate. Electron microscopy showed that molecules were usually linked at two or more nearby points. The junctions in most molecules were shorter than 300 nucleotides. Sometimes the region between two extreme points was separated into two arms, producing an ellipsoidal loop (called an eye loop). The junctions in these biparental joint molecules were frequently remote from the site of the gap. We infer that a free end of the interrupted strand crosseover to form a structure like a D loop which moved away from the gap by branch migration.

Bacterial Proteins↗
PubMed1980

Homologous pairing in genetic recombination: formation of D loops by combined action of recA protein and a helix-destabilizing protein.

Escherichia coli single-strand binding protein (SSB) or phage T4 gene 32 protein reduced the amount of recA protein required to catalyze the formation of D loops from double-stranded DNA and homologous single-stranded fragments. Neither SSB nor gene 32 protein alone catalyzed the formation of D loops, and excessive amounts of either protein, amounts that were sufficient to saturate the single strands, inhibited the formation of D loops completely. Both the stimulatory activity and the inhibitory activity of SSB resisted boiling, which is consistent with the known thermal stability of SSB, whereas the gene 32 protein was inactivated by heating. The formation of D loops in the presence of both recA protein and SSB required homologous DNA and ATP. Spermidine aided the combined action of SSB and recA protein in forming D loops, but Mg2+ alone was sufficient as a counterion.

Bacterial Proteins↗
PubMed1980

Effects of CS-386 and diazepam upon the gastric contraction and excitation of lumbar gamma-motoneurons following stimulation of the hypothalamus in the cat.

Effects of a new minor tranquilizer, CS-386 and diazepam were studied upon the gastric contraction and excitation of lumbar gamma-motoneurons following stimulation of some of the brain structures as well as upon the spontaneous gastric motility in the cat. CS-386 inhibited the hypothalamus-induced gastric contraction with little changes in spontaneous motility at doses of 5 and 10 mg/kg (i.d.). Diazepam inhibited both the hypothalamus-induced contraction and spontaneous motility at these doses. The vagal nerve-induced gastric contraction was suppressed by diazepam (5 mg/kg, i.d.) but not by the same dose of CS-386. Bemegride (5 mg/kg, i.v.) antagonized almost completely the depression caused by 5 mg/kg of CS-386, but not that by a dose of 10 mg/kg or 5 as well as 10 mg/kg of diazepam. Excitation of the lumbar gamma-motoneuron following stimulation of the posterior hypothalamus or the mesencephalic reticular formation was depressed by CS-386 or diazepam (10 mg/kg, p.o.), but not by lower doses. Based on the these evidences, it was suggested that CS-386 could be effective in stress-induced gastric lesions with lower side effects in digestive organs than diazepam.

Animals↗
PubMed1980

[Subacute toxicity test of cefoperazone in beagle dogs with the intravenous administration for 3 months (author's transl)].

The subacute toxicity test of cefoperazone (CPZ) in Beagle dogs with the intravenous administration for 35 days has been reported from our laboratory. In the present experiments, the subacute toxicity test of CPZ in Beagle dogs was carried out for longer administration period than before. CPZ was given intravenously to each group (2 or 4 dogs) at dose level of 100 mg/kg/day, 200 mg/kg/day and 400 mg/kg/day respectively for 3 months. Cefazolin (CEZ) was used intravenously for positive control using 4 dogs at dose level of 200 mg/kg/day and physiological saline was given intravenously to 2 dogs for 3 months. 1) In Beagle dogs received high dose of CPZ, transient vomiting, salivation and diarrhea were observed immediately after the administration. 2) Signs of anemia, such as decrease of erythrocyte and value of hemoglobin and hematocrit, and increase of reticulocytes of the peripheral blood and in fragility of red cell associated with decrease of food intake, were observed in 2 female dogs given CPZ of 400 mg/kg/day. In only one of these dogs, a positive reaction of COOMBS' test was shown. The anemia recognized in these 2 dogs seems to be of hemolytic nature. 3) The weight of thymus was decreased in all of 4 dogs given CPZ at 400 mg/kg/day and in 2 out of 4 dogs given CPZ at 200 mg/kg/day, respectively. 4) Based on the fact that no abnormalities were found in dogs given CPZ at 200 mg/kg/day except a slight decrease of weight of thymus in some of them, the maximum safety dose of CPZ was thought to be 200 mg/kg/day.

Animals↗
PubMed1980

[Subacute toxicity test of cefoperazone in beagle dogs with the intramuscular administration for 3 months (author's transl)].

The subacute toxicity test of cefoperazone (CPZ), a new cephalosporin antibiotic, was carried out in both sexes of Beagle dogs. CPZ was injected in Beagle dogs intramuscularly at dose levels of 500, 250 and 125 mg/kg/day for 3 months. The same amount of physiological saline was injected to control dogs intramuscularly for 3 months. The following results were obtained: 1) Sign of severe pain was shown immediately after injection in groups of CPZ at 500 and 250 mg/kg/day. In the same groups, the focal necrosis, hemorrhage, cell infiltration and fibrosis of muscles of injected site were noted microscopically. 2) In only one out of 6 dogs given CPZ at 500 mg/kg/day for 3 months, decrease of red blood cells and in values of hemoglobin and hematocrit an increase of reticulocytes in the peripheral blood were observed. In the same dog, splenomegaly and extramedullary hematopoiesis in the liver was found histopathologically, and in addition, the body weight and the food intake decreased during the administration period, associated with the development of anemia. 3) In dogs receiving up to 250 mg/kg/day, atrophy of the thymus was recognized at autopsy and slight decrease of cortical lymphocytes was seen histopathologically. 4) Based on these results, the maximum safety dose of CPZ was thought to be 125 mg/kg/day from the present experiment.

Animals↗