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Biomedical subjects

S Furuta

Publications and source records attributed to S Furuta.

At least 325 records · Page 18Linked to original sources
PubMed1987

Opioid activities of D-Arg2-substituted tetrapeptides.

The antinociceptive effects and mechanisms of action of H-Tyr-D-Ala-Phe-Gly-OH, H-Tyr-D-Arg-Phe-Gly-OH and H-Tyr-D-Arg-Phe-sarcosine(Sar)-OH have been investigated. The ED50 values of these peptides were 510.0, 8.2 and 2.0 pmol, respectively, when administered i.c.v. in the mouse tail-pressure test (dermorphin = 5.7 pmol and morphine = 1.2 nmol). These activities were remarkably potent and relatively long lasting. Their IC50 values were 676.8, 23.1 and 6.6 nM, respectively (dermorphin = 3.75 and morphine = 214.3 nM) in the guinea pig isolated ileum assay, and 138.50, 5.25 and 1.10 nM, respectively (dermorphin = 3.80 and morphine = 28.00 nM) in the radioreceptor assay utilizing [3H]naloxone as the opioid receptor ligand. In the evaluation of their inhibitory effects to enkephalin-degrading enzymes, the IC50 values of H-Tyr-D-Arg-Phe-Gly-OH, H-Tyr-D-Arg-Phe-Sar-OH and H-Tyr-D-Ala-Phe-Gly-OH were 5.4, 14.5 and more than 50.0 microM, respectively (bestatin = 0.1 microM) against aminopeptidase and 1.18, 1.40 and more than 50.0 microM, respectively (captopril = 0.38 and D-Phe-2S-, 3R-3-amino-2-hydroxy-4-phenylbutanoic acid = more than 100 microM) against the cleaving enzymes of enkephalin at its Gly3-Phe4 bond. The authors suggest that the marked antinociceptive potency of H-Tyr-D-Arg-Phe-Gly-OH and H-Tyr-D-Arg-Phe-Sar-OH is mainly due to high opioid receptor affinity. Their inhibitory effects on enkephalin-degrading enzymes and enzymatic stability also greatly contribute to their potent and long-lasting opioid activities.

Animals↗
PubMed1987

Defective hepatic anion transport in variegate porphyria.

A 29-yr-old man with neurological symptoms that included tremor, dysarthria, and loss of consciousness was diagnosed as having variegate porphyria, because of increased urinary excretion of delta-aminolevulinic acid, porphobilinogen, uroporphyrin, and coproporphyrin, and increased fecal uro-, copro-, and protoporphyrins. He showed marked retention of indocyanine green (R15 min: 53%-78%) and bromosulfophthalein (R45 min: 24%-10%) as well. The kinetic analysis revealed that both hepatic uptake and hepatic excretion were decreased for both dyes. Results of other liver function tests were unremarkable except for intermittent hyperbilirubinemia (0.7-3.3 mg/100 ml), of which the ratio of conjugated and unconjugated fraction was between 0.7 and 1.2. Binding of serum protein and indocyanine green or bromosulfophthalein was normal. An angiographic and scintigraphic study of the liver was normal. A minimal deposition of hemosiderin pigment was found in liver biopsy specimen without other abnormalities. Deposition of porphyrin was not present in the liver. Plasma exchange and erythrocytapheresis did not show any beneficial effects on the clinical and laboratory abnormalities of the patient. A possible relationship between variegate porphyria and defective hepatic anion transport is discussed.

Adult↗
PubMed1986

Significance of IgM antibody to hepatitis B core antigen for the differential diagnosis of acute and chronic hepatitis B virus infection and for the evaluation of the inflammatory activity of type B chronic liver diseases.

IgM antibody to hepatitis B core antigen (anti-HBc) was assayed using a commercial kit in acute and chronic hepatitis B virus (HBV) infection and evaluated for its diagnostic and clinical significance. IgM anti-HBc was positive in all of 21 cases with type B acute hepatitis in the acute phase, and was also detected in 5 of 20 cases with type B chronic persistent hepatitis, in 4 of 20 patients with type B chronic active hepatitis and in one of 10 with type B liver cirrhosis. The absence of this marker was noted in all of 20 asymptomatic hepatitis B surface antigen (HBsAg) carriers and in 50 with HBsAg-negative patients with liver disease and in 200 healthy blood donors. The cut-off index of IgM anti-HBc was greater than 2.0 in all serum samples obtained in the acute phase of type B acute hepatitis, but was below 2.0 in type B chronic liver disease. A close relationship was found between the presence of IgM anti-HBc and the degree of inflammatory activity in patients with HBsAg-positive chronic liver disease. These data show that examination of IgM anti-HBc is useful in distingushing type B acute hepatitis from type B chronic liver disease, and also in evaluating the severity of disease in type B chronic liver disease.

Acute Disease↗
PubMed1986

Complete nucleotide sequence of cDNA and deduced amino acid sequence of rat liver catalase.

We have isolated five cDNA clones for rat liver catalase (hydrogen peroxide:hydrogen peroxide oxidoreductase, EC 1.11.1.6). These clones overlapped with each other and covered the entire length of the mRNA, which had been estimated to be 2.4 kilobases long by blot hybridization analysis of electrophoretically fractionated RNA. Nucleotide sequencing was carried out on these five clones and the composite nucleotide sequence of catalase cDNA was determined. The 5' noncoding region contained 83 bases and was followed by 1581 bases of an open reading frame that encoded 527 amino acids. The 3' noncoding region was 831 bases long and contained long repeats of the unit AC. The amino acid sequence deduced from the nucleotide sequence of the cDNAs showed about 90% homology with the reported primary structure of bovine liver catalase. The molecular weight of rat liver catalase was calculated to be 59,758 from the predicted amino acid sequence. The amino acid residues in contact with the heme group are completely identical for bovine liver and rat liver catalases. The amino acid sequence at the COOH terminus was confirmed by the results of carboxypeptidase P treatment of the protein purified from rat liver in the presence of leupeptin. Rat liver catalase has no cleavable signal peptide for translocation of the enzyme into peroxisomes.

Amino Acid Sequence↗
PubMed1986

Study of the absorption site of cimetidine.

The optimal absorption site of cimetidine was assessed in rats. The ileac pH value (measured by a pH meter with a micro pH combination electrode) was slightly higher than that in other intestinal sites, and the absorption rate constant (ka) following the administration of cimetidine into the ligated ileac loop was larger than that in the ligated duodenal and jejunal loops. It is suggested that the ileum is the optimal absorption site of cimetidine. On administration of cimetidine into the ligated and unligated intestines, the ka values of either the duodenum or the ileum were found to be almost the same between the ligated and unligated cases. However, the ka value of the jejunum in the unligated case was slightly larger than that in the ligated case. Thus, it is suggested that cimetidine is completely absorbed in the duodenum and ileum during its passage through these intestinal sites, but at the jejunum an unabsorbed fraction of cimetidine passes to the ileum, where it is absorbed completely. Based on these results, a pharmacokinetic model for the absorption of cimetidine following oral administration was designed, in which gastric, duodenal, jejunal, and ileac compartments were included separately but enterohepatic circulation was not included, because the biliary excretion of cimetidine following intravenous and oral administrations were generally lower than 2% of the dose. The value of k41 was ca. 4 times larger than that of k45, and the value of k45 could be approximated to zero in the model.

Animals↗
PubMed1986

Effect of metoclopramide on the absorption of cimetidine in rats.

Metoclopramide was found to increase the absorption rate constant (ka) of cimetidine by the duodenum and jejunum in both ligated and unligated rats. The increase of ka of cimetidine in the ligated rats cannot be interpreted in terms of an increase in the gastric emptying rate, which has been suggested to be the main effect of metoclopramide. The pH values of the stomach, duodenum and jejunum increased following the administration of metoclopramide. Atropine also increased the pH value of the duodenum, but it did not increase the ka of cimetidine. Consequently, the increase of ka of cimetidine, following administration of metoclopramide, was not due to the elevation of intestinal pH. On the other hand, metoclopramide significantly increased the blood flow by about 67.3 and 29.7% at the duodenum and jejunum, respectively, when the intestinal blood flow was measured by the hydrogen clearance method. Atropine had no effect on the intestinal blood flow. Based on these results, it was concluded that the increase of intestinal blood flow may be one of the factors for the increase of ka of cimetidine following the administration of metoclopramide. From the results of multi-line fittings of the plasma concentration data following oral, intraduodenal, intrajejunal and intraileac administrations of cimetidine with metoclopramide treatment, it was suggested that metoclopramide increased the intestinal transit time of subsequently administered drugs, as well as the gastric emptying rate.

Animals↗
PubMed1986

[PTCA in patients undergoing coronary bypass surgery and its potential availability: when can PTCA be an alternative to coronary artery bypass grafting?].

The potential availability of percutaneous transluminal coronary angioplasty (PTCA) was retrospectively evaluated for the responsible lesions among grafted vessels of 149 patients who underwent coronary artery bypass grafting (CABG). The lesions suitable for PTCA were defined as discrete, segmental, subtotal and noncalcific, in proximal or middle portions of the major coronary arteries. Patients with left main trunk lesions, those with obstruction of two major coronary arteries, and those with lesions in donor arteries of jeopardized collaterals were excluded. Ninety-seven (31%) of a total of 308 grafted lesions were appropriate for PTCA. These included 38% of left anterior descending artery (LAD) lesions, 39% of left circumflex artery (CX) lesions, and 14% of right coronary artery (RCA) lesions. At least one lesion of 77 (52%) of 149 patients was suitable for PTCA. These included 66% of single vessel graft candidates, 54% of double vessel graft candidates, and 38% of triple or more vessel graft candidates. Ideal candidates for PTCA were 34 patients (23%) in whom all lesions in the grafted vessels were thought to be appropriate for PTCA, and these included 25 (LAD: 23, CX: 1, RCA: 1) of 38 single vessel graft candidates and nine (LAD + RCA: 6, LAD + CX: 2, CX + RCA: 1) of 111 multivessel graft candidates. There was no significant difference between the clinical characteristics of the patients ideally suited for PTCA and the remaining patients. Additional 25 candidates for multivessel grafting, whose lesions were appropriate for PTCA except that of the LAD, were considered limited candidates for PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1986

[Mitral regurgitation due to abnormal reinsertion of chordae tendineae (looping) of the posterior mitral leaflet: clinical and echocardiographic features].

Two-dimensional (2D) echocardiographic and clinical characteristics of patients with mitral regurgitation (MR) due to abnormal reinsertion of chordae tendineae (looping) in the middle scallop of the posterior leaflet were described and compared with those of patients with chordal rupture of the posterior leaflet. Twenty-five patients with posterior mitral valve prolapse who underwent mitral valve replacement were studied. They were categorized in three groups; 14 patients with MR due to ruptured chordae tendineae (RCT) of the posterior leaflet (RCT group); three patients with looping of the chordae tendineae in the middle scallop of the posterior leaflet (looping group); and eight patients with both RCT and looping (looping + RCT group). It was difficult to distinguish the looping group from the other two groups by their 2D echocardiographic findings, which were characteristic of those of RCT. However, the following findings were more frequently encountered in the patients with looping than in those without: 1) aberrant or absent systolic coaptation with salient arc of the posterior leaflet, observed in six of the RCT group (43%), two in the looping group (67%) and seven in the looping + RCT group (88%); 2) with thickened edges of the posterior leaflet, shown in three of the RCT group (21%), two of the looping group (67%) and five of the looping + RCT group (63%) in the long-axis view, and also noticed in four of the RCT group (29%), two of the looping group (67%) and six of the looping + RCT group (75%) in the short-axis view. In the clinical history, the onset of a heart murmur, congestive heart failure and surgical treatment occurred at significantly younger ages in the looping group than in the RCT group. As for hemodynamic parameters, pulmonary hypertension was significantly milder in the looping group than in the RCT group. In conclusion, although 2D echocardiographic findings of patients with looping were similar to those of patients with RCT, it seemed possible to differentiate the looping group from the RCT group by the 2D finding of a prolapsed posterior mitral valve with a salient arc and a thickened edge. It was also suggested that the looping of chordae tendineae in the middle scallop of the posterior leaflet was congenital in origin.

Adolescent↗