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Biomedical subjects

H Kanazawa

Publications and source records attributed to H Kanazawa.

At least 199 records · Page 11Linked to original sources
PubMed1991

[Surgical management of valve replacement in children].

From 1965 to 1990, 49 valve replacements were performed on 43 patients under the age of 15. Mitral valve replacements were performed on 21 patients, and re-replacements were done on 4 of them afterwards. In the first 9 mitral valve replacements before 1974, Starr-Edwards (S-E) ball valves were used. Five of these patients died in the hospital (early mortality rate was 56%). Since 1975, bioprosthetic valves were used in three cases, but all of these valves ceased to function due to primary tissue failure (PTF) within 3 years. Consequently, SJM valves are now used as a first choice. Ten aortic valve replacements were performed on 9 patients with the results of one early death, two late deaths, and one late re-operation. Tricuspid valve replacements were performed on 11 patients, 5 of whom utilized S-E ball valves. Three of the five patients died in the hospital. One patient was re-operated on, swapping the S-E ball valve for the SJM valve. SJM valves were used primarily in 2 patients, and bioprosthetic valves in 4. Two patients died, one with a SJM valve, and the other with a bioprosthetic valve. Two pulmonary valve replacements were performed, one employing a SJM valve, the other a bioprosthetic valve. Two adult patients with SJM valve in the right side of the heart had thrombotic complications, though the patients with bioprosthetic valves had none. Atrioventricular valve replacements were performed on 5 patients under the age of 3, but all of them died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Histochemical changes of islet cells of Langerhans after hepatectomy and effect of glucagon and insulin].

It has been made by a number of studies that after hepatic resection, portal factors such as insulin and glucagon play an important role in liver regeneration. We have reported hypertrophy of Langerhans islands of dogs after partial hepatectomy. In the present study we attempted to clarify the mechanism of this hypertrophy. In a control group, a forty-percent hepatectomy was carried out. One and four weeks after surgery, 0.5g/kg of glucose was administered intravenously followed by a blood sampling from the portal vein to measure the changes of glucose, insulin and glucagon respectively. In addition area changes of the islets of Langerhans after the operation were measured with PAP technique. In a GI group, the same experiment as in the control group was done and 1mg of glucagon and 2IU/kg of insulin were administered every morning after the operation. The following results were obtained. In the GI group, there were no decrease in portal plasma insulin level and no enlargement of the sizes of the islets four weeks after surgery.

Animals↗
PubMed1991

[Surgical management of congenital aortic valve stenosis in neonates and infants].

From 1985 to 1989, 4 neonates or infants (3 males and 1 female) underwent open valvotomy for severe aortic valve stenosis. In all patients, preoperative echocardiograms showed abnormal findings of endocardial fibroelastosis and/or poor performance of left ventricle. All patients underwent valvotomy using cardiopulmonary bypass. There was one early death from left ventricular failure. All other patients survived and the pressure gradient through aortic valve was reduced from 50-100 mmHg to 25-50 mmHg postoperatively. We conclude that infants with severe aortic valve stenosis should undergo open valvotomy before the manifestation of endocardial fibroelastosis and/or left ventricular muscle damage, and that open aortic valvotomy using cardiopulmonary bypass is most suitable method for severe aortic valve stenosis in infants.

Aortic Valve↗
PubMed1990

Suppression mutations in the defective beta subunit of F1-ATPase from Escherichia coli.

The Escherichia coli mutant of the proton-translocating ATPase KF11 (Kanazawa, H., Horiuchi, Y., Takagi, M., Ishino, Y., and Futai, M. (1980) J. Biochem. (Tokyo) 88, 695-703) has a defective beta subunit with serine being replaced by phenylalanine at codon 174. Four suppression mutants (RE10, RE17, RE18, and RE20) from this strain capable of growth on minimal plate agar supplemented by succinate were isolated. The original point mutation at codon 174 was intact in these strains. Additional point mutations, Ala-295 to Thr, Gly-149 to Ser, Leu-400 to Gln, Ala-295 to Pro, for RE10, RE17, RE18, and RE20, respectively, were identified by the polymerase chain reaction and sequencing. These mutations, except for RE10, were confirmed as a single mutation conferring a suppressive phenotype by genetic suppression assay using KF11 as the host cells. The results indicated that Ser-174 has functional interaction with Gly-149, Ala-295, and Leu-400. The residues are located within the previously estimated catalytic domain of the beta subunit, indicating that this domain is indeed folded for the active site of catalytic function. Growth rates of the revertants in the minimal medium with succinate increased compared with that of KF11, showing that ATP synthesis recovered to some extent. The ATP hydrolytic activity in the revertant membranes increased in RE17 and RE20 but did not in RE10 and RE18, suggesting that synthesis and hydrolysis are not necessarily reversible in the proton-translocating ATPase (F1F0).

Amino Acid Sequence↗
PubMed1990

Rapid purification and characterization of F1-ATPase of Vibrio parahaemolyticus.

The F1 portion of H(+)-translocating ATPase as purified from membrane vesicles of Vibrio parahaemolyticus by a rapid procedure. The whole purification process (from culture of cells to purification of the enzyme) could be completed in 1 day. The F1-ATPase consists of five subunits (alpha, beta, gamma, delta and epsilon) like F1 of Escherichia coli and other microorganisms. The F1-ATPase of V. parahaemolyticus showed some interesting properties. Its activity was greatly stimulated by high concentrations (about 0.5 M) of SO4(2-), SO3(2-) and CH3COO-, their effects decreasing in this order. Among the anions tested, Cl- and NO3- were ineffective, or rather inhibitory, and cations had no significant effects. Ethanol (or methanol) stimulated the activity 2- to 3-fold. The activity was inhibited by 4-acetamido-4'-isothiocyanostilbene 2,2'-disulfonate (SITS) (an anion exchanger inhibitor), tetrachlorosalicylanilide (TCS) (an H+ conductor), azide and N-ethylmaleimide. Zinc inhibited the activity only slightly, although it strongly inhibited the ATPase activity in membrane vesicles.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1990

Simultaneous determination of ginsenosides and saikosaponins by high-performance liquid chromatography.

Octadecyl porous glass was used as the packing for reversed-phase high-performance liquid chromatography. A mixture of ginsenosides and saikosaponins (saponins of ginseng and bupleurum root, respectively) were analysed with detection at 203 nm. A well resolved chromatogram of ginsenoside Rb1, Rc, Rb2 and Rd and saikosaponin a, b2 and c was obtained with acetonitrile-water (25.5:74.5) as the mobile phase. The whole separation was achieved in 20 min with a flow-rate of 1.5 ml/min. Calibration graphs for ginsenoside Rb1, Rc, Rb2 and Rd and saikosaponin a and c were linear up to 5 micrograms. Rapid and accurate simultaneous determinations of the saponins are possible by the described method.

Chromatography, High Pressure Liquid↗
PubMed1990

Effect of glucagon on bile acid metabolism after resection of liver cancer in patients with cirrhosis.

After hepatectomy patients with cirrhosis and liver cancer may develop progressive hepatic dysfunction and eventually hepatic failure. Insulin and glucagon are often used to treat certain kinds of hepatic dysfunction and hepatic insufficiency. We investigated the effect of glucagon on bile acid metabolism and pancreatic endocrine function. In 7 patients with severe cirrhosis and cancer of the liver, 1 mg of glucagon was injected intravenously pre- and post-operatively, and total bile acids, C-AMP, and bile acid fractions were determined. In the pre-operative glucagon tolerance test, the C-AMP level rose from a baseline of 14 +/- 0.8 PMol/ml to 362 +/- 94 PMol/ml 30 min after the injection of glucagon (p less than 0.01); and the level of total bile acids decreased from a baseline of 28 +/- 9 microMol/ml to 11 +/- 3 microMol/ml 60 min after the injection of glucagon. The post-operative C-AMP level increased from a baseline of 13 +/- 1 PMol/ml to 192 +/- 58 PMol/ml level of 30 min after the injection of glucagon (p less than 0.01), and the post-operative level of total bile acids decreased from a baseline of 64 +/- 20 microMol/ml to 26 +/- 7 microMol/ml 60 min after the injection of glucagon. There was a significant correlation between the 5-min increment ratio of C-AMP and the decrement ratio of total bile acids (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Bile Acids and Salts↗
PubMed1990

Concanavalin A affects beta-tubulin mRNA expression during neuritic processes of mouse neuroblastoma N18TG2 cells in a different manner from colchicine.

Addition of concanavalin A (Con A) to mouse neuroblastoma N18TG2 cells cultured with dibutyryl-cAMP which can stimulate neurite outgrowth, stopped the neuritic processes effectively. The extended neurites showed a gradual retraction for at least 8 hrs after addition of Con A, while addition of colchicine caused rapid retraction of the neurites. Immunocytochemistry showed that the addition of Con A did not disorganize the microtubules but the addition of colchicine did. The increase in beta-tubulin mRNA expression which was observed after cell culture and after stimulation by dB-cAMP was suppressed by the addition of Con A. Con A did not affect the beta-tubulin mRNA expression when the cells had already been cultured, while colchicine drastically decreased it. Thus, Con A appeared to affect the beta-tubulin mRNA expression in a different manner from colchicine, probably through inhibition of cell movement.

Animals↗
PubMed1990

Effect of intravenously administered fat emulsion on liver function in totally depancreatized dogs.

Total Pancreatectomy was performed under nembutal anesthesia in 16 adult mongrel dogs after a 24-hour fast, and the depancreatized dogs were given parenteral nutrition containing fat emulsion. Serum lipids, intravenous fat tolerance and post-heparin lipolytic activity were determined and liver biopsy was done to demonstrate the presence or absence of fatty liver. The animals were divided into three groups: group A (n = 6) received fat emulsion 1 g/kg/day; group B (n = 5), fat emulsion 2 g/kg/day; and group C (n = 5), no fat emulsion. Blood levels of cholesterol and phospholipid were increased in group B, while only a mild elevation of the blood triglyceride (TG) level was noted in group A. In group C, cholesterol and phospholipid levels were decreased, and hypoglycemia was liable to occur. The rate of disappearance of blood fat (K2) was decreased two weeks after surgery in group B, but there were no significant change in the other two groups. These findings suggest that if insulin is present, the administration of fat emulsion will not cause fatty liver.

Animals↗
PubMed1990

Amplification of HTLV-1-related sequences among patients with neurological disorders in highly endemic Nagasaki: lack of evidence for association of HTLV-1 with multiple sclerosis.

We studied DNA sequences homologous to HTLV-1 in peripheral blood mononuclear cells (PBMC) of 30 patients with neurological disorders in Kyushu, where HTLV-1 is highly endemic. The regions of HTLV-1 amplified by means of polymerase chain reaction (PCR) included U3, U5, gag, pol, env and pX. Our system specifically detected HTLV-1 sequences only from HTLV-1-positive cells and was sufficiently sensitive to detect one proviral copy per 10(3) PBMC. All PCR-positive cases were seropositive, including 4 cases of tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM) (4/4), and one case each of myasthenia gravis (1/7) and multiple sclerosis (1/8). The PCR-positive rate of patients, excluding 4 TSP/HAM cases, was 8% (2/26), which is similar to the seroprevalence of the adult population in the area. The data suggest that multiple sclerosis is not associated with prototype HTLV-1.

Adult↗
PubMed1990

Preparative high-performance liquid chromatography on chemically modified porous glass. Isolation of saponins from ginseng.

Preparative high-performance liquid chromatography on octadecylsilyl porous glass (pore size, 550 A) with acetonitrile-water as the mobile phase was applied for the isolation of saponins from Panax ginseng. In a single run, several milligrams of pure ginsenosides were obtained from 10 g of roots of Panax ginseng. The method was simple, rapid and convenient and should be applicable to isolation of other saponins of crude drugs.

Chemical Phenomena↗
PubMed1990

Characteristics of the H(+)-translocating adenosine triphosphatase of Vibrio parahaemolyticus.

We have characterized H(+)-translocating adenosine triphosphatase (ATPase) in membrane vesicles of Vibrio parahaemolyticus. The ATPase required high concentrations (about 0.5 M) of Na2SO4 (or other salts) for its maximum activity. Magnesium ion stimulated the ATPase activity, but Ca2+ did not. The activity of ATPase was inhibited by tetrachlorosalicylanilide, an H+ conductor, but not by another H+ conductor, carbonylcyanide-m-chlorophenylhydrazone. The activity was strongly inhibited by dicyclohexylcarbodiimide or Zn2+, and partially inhibited by azide, but not at all by vanadate.

Cell Membrane↗
PubMed1990

Accelerating effect of glutathione on hydroxylation of phenylalanine by stimulated polymorphonuclear leukocytes.

Sulfhydryl compounds significantly accelerated the hydroxylation of phenylalanine by stimulated polymorphonuclear leukocytes. The reduced form of glutathione (G-SH) was most effective. The hydroxylation reaction in the presence of G-SH was largely prevented by superoxide dismutase and hydroxyl radical scavengers. The results suggest that a much faster production of hydroxyl radical may occur in a reaction mixture containing both G-SH and stimulated polymorphonuclear leukocytes than in that containing stimulated polymorphonuclear leukocytes alone.

Animals↗
PubMed1990

A new RFLP in intron 1 of the human c-Ha-ras1 gene and its close relationship with the variable tandem repeats in the region 3' to the gene.

Based on restriction fragment length polymorphism (RFLP) analysis of BamHI or MspI fragments, the human c-Ha-ras1 alleles could be divided into two major groups, one having about 80 copies of a 28 base pair (bp) sequence in the variable tandem repeat (VTR) region 1.4-kilobase pairs (kb) downstream from the end of the coding exon and the other having 40 copies of the sequence. We found a second RFLP in intron 1 of the c-Ha-ras1 gene at a position about 80 bp upstream from the 5'-end of exon 1. The size of the PstI fragments carrying this region is either 371 or 359 bp depending on the numbers of a hexanucleotide sequence, GGGCCT. In larger fragments, the unit sequence was repeated four times, while in smaller fragments it was repeated twice. Unexpectedly, we found that the alleles with 80 copies of the 28 bp sequence in the VTR region all carried two repeats of GGGCCT in intron 1, while alleles with 40 copies all had four repeats of the GGGCCT sequence.

Base Sequence↗
PubMed1990

[Long-term results of valve replacement in the right side of the heart in congenital heart disease--comparative study of bioprosthetic valve and mechanical valve].

Valve replacements in the right side of the heart (TVR and PVR) were done on 16 patients with congenital heart disease, mainly tetralogy of Fallot and Ebstein anomaly. Including reoperations, 19 operations were performed on them and 20 artificial valves were inserted. Ten mechanical valves (7 St. Jude Medical valves, 3 Starr-Edwards valves) and 10 bioprosthetic valves (7 Carpentier-Edwards valves, 3 Ionescu-Shiley valves) were used. Age at valve replacement ranged from 9 to 52 years (mean 23.0 years), and the follow-up period was 1.28-19.8 years (mean 5.7 years). Including 2 sudden deaths, late death occurred in 4 patients, on all of whom mechanical valve replacements were done at the primary operation. Five-year survival rate of all patients was 76.4 +/- 12.1%, and 10-year survival rate was 63.6 +/- 15.4%. All the patients who received bioprosthesis at the primary operation survived at the time of this follow-up study. On the contrary, long-term results of mechanical valve was unsatisfactory with the 5-year survival of 62.5 +/- 17.1%. In spite of anti-coagulation therapy with warfarin, three patients with mechanical valve complicated thrombotic valves, which necessitated re-operations. Calcified bioprosthetic valve occurred in one patient with I-S valve 8.5 years after the implantation. Five-year complication-free rate was 87.5 +/- 11.7% for bioprosthesis, whereas it was 50.0 +/- 15.8% for mechanical valve (p less than 0.056). It is concluded that the bioprosthesis is the first choice for the valve replacement in the right side of the heart in congenital heart disease.

Adolescent↗
PubMed1990

[Delayed sternal closure following open-heart surgery in infants and children].

Between January, 1982, and December, 1987, 14 patients failed to approximate sternum after open-heart surgery in infants and children. The indications for keeping sternum open were enlarged heart, myocardial edema, severe depression of myocardial contractility and reduced lung compliance due to pulmonary edema. Of the 14 patients, 9 underwent delayed sternal closure between 2nd and 13th postoperative day, and 4 were long-term survivals. All the rest of five patients who were left their sternum open, died of intractable cardiac failure within 16th postoperative day. During the sternum open, three patients suffered from complications-myocardial bleeding in one, and mediastinitis in two. But none of them directly related to the death, and one patient with mediastinitis successfully healed with closed mediastinal irrigation. Although the employment of the delayed sternal closure is rare and limited to the patient with severe heart failure, its judicious use adds advantages in the management of low cardiac output state in infants and children immediately postoperative period.

Cardiac Surgical Procedures↗
PubMed1989

Codon 61 mutations in the c-Harvey-ras gene in mouse skin tumors induced by 7,12-dimethylbenz[a]anthracene plus okadaic acid class tumor promoters.

Three okadaic acid class tumor promoters, okadaic acid, dinophysistoxin-1, and calyculin A, have potent tumor-promoting activity in two-stage carcinogenesis experiments on mouse skin. DNA isolated from tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) and each of these tumor promoters revealed the same mutation at the second nucleotide of codon 61 (CAA----CTA) in the c-Ha-ras gene, determined by the polymerase chain reaction procedure and DNA sequencing. Three potent 12-O-tetradecanoylphorbol-13-acetate (TPA)-type tumor promoters, TPA, teleocidin, and aplysiatoxin, showed the same effects. These results provide strong evidence that this mutation in the c-Ha-ras gene is due to a direct effect of DMBA rather than a selective effect of specific tumor promoters.

9,10-Dimethyl-1,2-benzanthracene↗