Biomedical subjects

M Kaneko

Publications and source records attributed to M Kaneko.

At least 19 recordsLinked to original sources

PubMed1992

Reversible interactions between plasminogen activators and plasminogen activator inhibitor-1.

We have shown that the urokinase (UK) kringle domain contains a high-affinity plasminogen activator inhibitor-1 (PAI-1) binding site, responsible for the 10-fold faster complex formation between UK and PAI-1 than between PAI-1 and low-molecular-weight urokinase (LMWUK). Complex formation between UK and PAI-1, but not between LMWUK and PAI-1, was suppressed 10-fold in the presence of peptide U-107 derived from the UK kringle domain. Peptide U-373 derived from the UK catalytic domain slowed complex formation between UK and PAI-1 and also LMWUK and PAI-1. Inactivation of tissue-type plasminogen activator (tPA) by PAI-1 was slowed 10-fold in the presence of peptides derived from the tPA finger and kringle-2 domains. DFP-inactivated (DIP) UK and both forms of DIP-tPA inhibited PAI-1 binding to U-107 and to U-373 whereas single-chain urokinase-type PA (scuPA) was unable to compete with either peptide for PAI-1 binding. These data suggest that the reversible PAI-1 binding site in the UK A-chain plays a role in the rapid association with PAI-1 as important as those that reside in the tPA A-chain and that reversible PAI-1 binding sites are expressed on the surface of UK upon conversion from scuPA, in contrast to tPA.

Amino Acid Sequence↗

PubMed1992

[Transjugular intrahepatic portosystemic stent shunt (TIPSS) with use of Rösch-Uchida transjugular liver access set--evaluation by CT and its clinical application].

Appropriateness of the Rösch-Uchida transjugular liver access set designed for TIPSS procedure was confirmed, especially about the catheter angle and effective length of the 20 G puncture needle, by CT analysis on three dimensional vascular anatomy of the liver. Clinically, TIPSS using the set was successfully made for two patients, connecting superior right hepatic vein with right portal vein in one patient and middle hepatic vein with left portal vein in another patient with hypoplastic right portal vein. Prior to TIPSS procedure, verification of vascular anatomy on CT images is the key to success of TIPSS in safe.

Evaluation Studies as Topic↗

PubMed1992

[Gianturco expandable metallic stents in the treatment of tumor thrombus in portal vein--preliminary clinical experience].

Two cases of hepatocellular carcinoma with protal vein invasion (Vp3) were successfully treated by Gianturco expandable metallic stents (GEMS). Each case was treated through the different approach, i.e. the percutaneous transhepatic or ileocolic venous route. GEMS was easily expanded within the protal vein and carcinoma thrombi were pushed against the walls, resulting in increase of portal blood flow. The GEMS might improve the impaired portal blood flow with hepatic failure and esophagogastric varices, in spite of the possibilities of dissemination and ingrowth of carcinoma thrombi.

Aged↗

PubMed1992

Decrease in heart mitochondrial creatine kinase activity due to oxygen free radicals.

This study was undertaken to examine the effects of oxygen free radicals on mitochondrial creatine kinase activity in rat heart. Xanthine plus xanthine oxidase (superoxide anion radical generating system) reduced mitochondrial creatine kinase activity both in a dose- and a time-dependent manner. Superoxide dismutase showed a protective effect on depression in creatine kinase activity due to xanthine plus xanthine oxidase. Hydrogen peroxide inhibited creatine kinase activity in a dose-dependent manner, this inhibition was protected by the addition of catalase. In order to understand the detailed mechanisms by which oxygen free radicals inhibit mitochondrial creatine kinase activity, the effects of oxygen free radicals on mitochondrial sulfhydryl groups were examined. Mitochondrial sulfhydryl groups contents were decreased by xanthine plus xanthine oxidase or hydrogen peroxide; this depression in sulfhydryl groups contents was prevented by the addition of superoxide dismutase or catalase. N-Ethylmaleimide (sulfhydryl group reagent) expressed inhibitory effects on the creatine kinase activity both in a dose- and a time-dependent manner; dithiothreitol or cysteine (sulfhydryl group reductant) showed protective effects on the creatine kinase activity depression induced by N-ethylmaleimide. Dithiothreitol or cysteine also blocked the depression of mitochondrial creatine kinase activity caused by xanthine plus xanthine oxidase or hydrogen peroxide. These results lead us to conclude that oxygen free radicals may inhibit mitochondrial creatine kinase activity by modifying sulfhydryl groups in the enzyme protein.

Animals↗

PubMed1992

Intrapulmonary sublesions detected before surgery in patients with lung cancer.

BACKGROUND: The treatment of patients with multiple intrapulmonary lesions remains controversial. METHODS: Fifty-three patients with lung cancer, in whom preoperative evaluation disclosed intrapulmonary nodules distinct from the main tumor, were analyzed retrospectively to establish the optimal treatment in such cases. RESULTS: These sublesions proved to be intrapulmonary metastases (PM) in 16 cases (30%), multiple primary lung cancers in 7 cases (13%), and various nonmalignant lesions in the others. The survival of the 53 patients, and of patients with clinical Stage I/II disease in particular, compared favorably with that of all patients with resected lung cancer. Those with multiple sublesions had a poorer prognosis, irrespective of their nature. Although patients with PM as sublesions often had clinically advanced cancer, metastatic foci, per se, did not influence the survival data as calculated by a multivariate analysis. CONCLUSIONS: The authors conclude that the existence of a solitary intrapulmonary sublesion should not preclude surgical treatment, unless surgery is contraindicated because of other clinical and radiologic findings.

Humans↗

PubMed1992

Changes in adrenergic receptors during the development of heart failure.

Moderate and severe stages of congestive heart failure due to the loss of myocardium upon coronary occlusion in rats was associated with an increase in alpha-adrenergic receptors and a decrease in beta-adrenergic receptors in the viable left ventricle. However, at early stages of heart failure the number of beta-adrenergic receptors was decreased without any changes in the number of alpha-adrenergic receptors. The affinities of these receptors to alpha receptor antagonist (3H-prazosin) and beta receptor antagonist (3H-dihydroalprenolol) were not altered in the failing hearts. On the other hand, the pattern of changes in both alpha- and beta-adrenergic receptors in heart membranes treated with oxygen free radical generating system was different from that seen in the failing hearts. In particular, the affinities for these receptors were decreased whereas the number of beta-receptors was increased and the number of alpha-receptors was decreased or unchanged. These results indicate that alterations in the adrenergic receptors in heart failure are not due to the formation of oxygen free radicals.

Animals↗

PubMed1992

[Transjugular intrahepatic portosystemic stent shunt (TIPSS)].

Our first clinical experience of TIPSS made for a 52-year-old patient with recurrent life threatening variceal bleeding is described. Although shunt-making between the right hepatic vein and the right portal vein and placement of Gianturco-Rösch Z stents were successfully made without significant complication related to the procedure, sufficient decompression of the portal vein pressure was not obtained because of compression on these stents at the tortuous portion of the shunting tract. Some technical problems of the procedure are also discussed, especially about choice of metallic stents and puncture technique.

Esophageal and Gastric Varices↗

PubMed1992

Inhibition of D-3-aminoisobutyrate-pyruvate aminotransferase by 5-fluorouracil and alpha-fluoro-beta-alanine.

Among pyrimidine derivatives, we found that 5-fluorouracil potently inhibited purified rat liver D-3-aminoisobutyrate-pyruvate aminotransferase, whereas 5-fluorouridine did so to a much lesser extent. 5-Fluorouracil acted as a competitive inhibitor against beta-alanine with a Ki of 56 microM, and was uncompetitive against pyruvic acid, with a Ki of 73 microM. alpha-Fluoro-beta-alanine, a metabolite of 5-fluorouracil, was also a competitive inhibitor with respect to beta-alanine with a Ki of 8.0 mM. 5-Fluorouracil acted also as a competitive inhibitor of 4-aminobutyrate aminotransferase with respect to beta-alanine with a Ki value of 1.9 mM, and was uncompetitive against 2-oxoglutaric acid, with a Ki of 1.8 mM.

Alanine Transaminase↗

PubMed1992

Properties of base-substituted and carboxyl-esterified analogues of griseolic acid, a potent cAMP phosphodiesterase inhibitor.

Griseolic acid (GA) is a potent cyclic AMP (cAMP) phosphodiesterase (PDE) inhibitor that has an adenine base and two carboxyl groups in its molecule (Nakagawa F, Okazaki T, Naito A, Iijima Y and Yamazaki M, J Antibiot 38: 823-829, 1985). GA analogues were synthesized in which the adenine group was substituted with guanine (6-deamino-2-amino-6-hydroxygriseolic acid, G-GA) or hypoxanthine (6-deamino-6-hydroxygriseolic acid, H-GA). Their inhibitory activities to cyclic GMP (cGMP) PDE and cAMP PDE were compared with GA. For cGMP PDE from rod outer segments of bovine retina, the IC50 values of GA, G-GA and H-GA were 18, 0.040 and 0.12 microM, respectively, with 0.25 microM cGMP as substrate. For type IV PDE isozyme from mouse 3T3 fibroblast cells, the IC50 values of GA, G-GA and H-GA were 0.021, 15 and 11 microM, respectively, with 0.25 microM cAMP as substrate. Thus, GA and G-GA were found to be base-selective inhibitors of type IV PDE of 3T3 cells and type V PDE of bovine retinas, respectively. Esters of carboxylic acids of GA were synthesized in order to increase permeability into cells, and their efficacy was tested by measuring the accumulation of cAMP in 3T3 cells. The dipivaloyloxymethyl ester of GA was found to increase cAMP levels at 0.1 microM, while GA and 3-isobutyl-1-methylxanthine were active only above 100 microM, and the dimethyl ester of GA was inactive. The dipivaloyloxymethyl ester of GA seems to exert its activity after conversion to GA in the cell, since the pivaloyloxymethyl ester was easily hydrolysed by the enzyme action and the dipivaloyloxymethyl ester of GA itself was much less potent an inhibitor of PDE. The dipivaloyloxymethyl ester of GA inhibited thrombin-induced aggregation of platelets and stimulated lipolysis of adipocytes at low concentrations.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Stimulatory guanine nucleotide-binding protein and adenylate cyclase activities in Bio 14.6 cardiomyopathic hamsters at the hypertrophic stage.

The Bio 14.6 cardiomyopathic Syrian hamster is an animal model of human idiopathic cardiomyopathy. The pathogenesis of the disease in this animal has not yet been clearly elucidated. It is well known that alpha- and beta-adrenergic receptors are increased in the myocardium of this animal, but that isoprenaline does not produce an augmented response. We examined the activity of cardiac stimulatory GTP-binding protein (Gs), which couple with beta-adrenergic receptors to stimulate adenylate cyclase, in Bio 14.6 cardiomyopathic hamsters at 90 and 160 days of age. The cardiac norepinephrine concentration was significantly increased in Bio 14.6 hamsters compared with control hamsters (F1B) at 90 days of age (1,739 +/- 120 vs 1,470 +/- 161 ng/g wet tissue weight, p less than 0.05). Cardiac forskolin-stimulated adenylate cyclase activities at 90 and 160 days of age were lower in the cardiomyopathic hamsters than in the F1B controls (90 days old: 98 +/- 24 vs 122 +/- 29 pmol/min/mg protein, p less than 0.05; 160 days old: 74 +/- 13 vs 124 +/- 28 pmol/min/mg protein, p less than 0.01). Cardiac Gs activities at 90 and 160 days of age were significantly lower in Bio 14.6 hamsters than those in F1B hamsters (90 days old: 204 +/- 42 vs 259 +/- 49 pmol/min/mg protein, p less than 0.05; 160 days old: 156 +/- 39 vs 211 +/- 60 pmol/min/mg protein, p less than 0.05). We thus demonstrated functional defects in cardiac Gs protein and adenylate cyclase activity in the Bio 14.6 cardiomyopathic hamsters at 90 to 160 days of age (the hypertrophic stage of cardiomyopathy).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗

PubMed1992

Stable isotope aided nuclear magnetic resonance study to investigate the receptor-binding site of human interleukin 1 beta.

Resonance assignments for interleukin 1 beta at neutral pH were made by using three-dimensional NMR in combination with specific labeling and double-labeling methods with stable isotopes. On the basis of the present assignments, 15N single-quantum coherence spectra of N-terminal truncated and fusion mutants were compared with that of the wild-type. Although these mutants have reduced biological activity, they showed 15N-SQC spectra similar to that of the wild-type. However, small but significant chemical shift changes were observed for amino acid residues within a loop 86-99, in spite of the modification at the N-terminus, supporting the idea that this loop forms a biologically active part of interleukin 1 beta. Receptor-binding activity was studied for mutants (Asp-93)-, (Leu-93)- and des-(Arg-98)interleukin 1 beta's. The results show significant loss of the receptor-binding activity. The N-terminus, the C-terminus, and the loop 86-99 form a part of the open end of a beta-barrel [Finzel, B. C., Clancy, L. L., Holland, D. R., Muchmore, S. W., Watenpaugh, K. D., & Einspahr, H. M. (1989) J. Mol. Biol. 209, 779-791; Clore, G. M., Wingfield, P. T., & Gronenborn, A. M. (1991) Biochemistry 30, 2315-2323], which forms the receptor-binding site of IL-1 beta.

Amides↗

PubMed1992

Craniosynostosis in association with medulloblastoma.

A case of a 13-month-old boy with craniosynostosis associated with medulloblastoma was presented. Sagittal suture was prematurely closed, and coronal and lambdoid sutures were widely separated. A large infiltrative tumor in the midcerebellar region was partially removed and treated by irradiation and chemotherapy. A review of the current literature failed to reveal a similar report.

Cerebellar Neoplasms↗

PubMed1992

Role of TraT protein, an anticomplementary protein produced in Escherichia coli by R100 factor, in serum resistance.

Escherichia coli K12 strain W3110/SM bearing a plasmid containing the traT gene (traT+ strain) was more resistant to the bactericidal activity of guinea pig serum than the same strain bearing this plasmid without the traT gene (traT- strain). A murine mAb was generated against synthetic TraT peptide (86-99). This antibody reacted only with denatured TraT protein, but it was used for monitoring TraT protein by immunoblotting during purification of the protein. Six mAb were then generated against partially purified traT protein from the solubilized membrane fraction of the traT+ strain. These mAb reacted with the native protein even on living cells, and their F(ab) fragments were found to suppress the inhibitory effect of the TraT protein on the bactericidal activity of serum. TraT protein was purified from solubilized membranes of the traT+ strain by ion exchange and gel filtration chromatographies. The purified TraT protein inhibited the lysis of sensitized erythrocytes by serum complement. Its inhibitory action was mainly on the C6 step. It strongly inhibited the reaction of C6 with EAC14b2a3b and excess C5, C7, C8, and C9. TraT protein also inhibited the reaction of C7-deficient human serum with guinea pig erythrocytes when it was activated by cobra venom factor. It did not inhibit the reaction of preformed C5b6 complexes. However, TraT did not have any effect on the cleavage of 125I[C5] to 125I[C5b] in similar conditions. It also partially inhibited the reaction steps of C4, C5, and factor B and limited guinea pig complement serum in 0.1% gelatin veronal buffered saline, pH 7.4, containing 10 mM EDTA with their respective preceding intermediate cells. It had no effect on either the binding of C3 to EAC14b2a or the cleavage of C3b by factors H and I. TraT protein probably inhibits the formation of C5b6 complex or causes structural alteration of the complex to a nonfunctional form.

Amino Acid Sequence↗

PubMed1992

Magnetic resonance angiography of extracranial carotid and vertebral arteries, including their origins: comparison with digital subtraction angiography.

Although carotid bifurcation stenoses are not the only lesions of the extracranial cerebral arteries, magnetic resonance angiographic (MRA) studies to date have concentrated on the carotid bifurcation. We compared digital subtraction angiography of the extracranial portions of the cerebral arteries with MRA using an ordinary body coil, the time-of-flight method, and multiple transverse slabs which covered the arteries down to the aortic arch. Twenty-two patients (15 with arteriosclerotic diseases, 4 with aortitis, and 3 with tumours) had MRA using a 1.5 T magnet system with a three-dimensional fast imaging with steady state precession (FISP) technique. Thirty-nine carotid and 39 vertebral arteries were assessed by three radiologists with regard to stenoses or occlusions, graded as normal, mild (< 30%), moderate (30-60%) or severe (> 60%) stenosis, or occluded. Grading corresponded well in 81%; stenoses appeared more marked on MRA in 14% and were seen less clearly on MRA in 5%. When 26 carotid bifurcations were assessed separately, grading corresponded well in 95%. MRA is the only method which can display the whole course of the extracranial carotid and vertebral arteries non-invasively and satisfactorily.

Adolescent↗

PubMed1992

Cardiac function and myocardial performance of 24-hour-preserved asphyxiated canine hearts.

A method of 24-hour storage of asphyxiated canine hearts for orthotopic cardiac transplantation was studied to expand the geographical size of the donor pool. Left ventricular function of asphyxiated hearts preserved for 24 hours (group 1, n = 8) was compared with that of hearts donated on-site (group 2, n = 5). Group 1 donors were pretreated with verapamil hydrochloride, propranolol hydrochloride, and prostacyclin. The donor hearts were perfused with warm blood cardioplegia in situ after 10 minutes of asphyxiation and then perfused with cold crystalloid cardioplegia for 2 hours. The hearts were excised and stored in ice-cold University of Wisconsin solution for 22 hours. At orthotopic transplantation, coronary perfusion with warm blood cardioplegia was performed before the graft aorta was unclamped. Conventional cardiac variables (eg, cardiac output and maximum rate of rise of left ventricular pressure), myocardial performance, and diastolic compliance of grafted hearts were assessed 1 hour after weaning from bypass. All recipients in both groups were easily weaned from cardiopulmonary bypass without inotropic agents, and there were no significant differences in cardiac variables between the two groups. These results strongly suggest that cadaver hearts can be preserved for 24 hours with satisfactory cardiac function.

Animals↗

PubMed1992

Coronary bypass using arterial grafts in homozygous familial hypercholesterolemia.

A 25-year-old man with homozygous familial hypercholesterolemia who had severe coronary artery disease underwent coronary revascularization by combined arterial grafts using bilateral internal mammary arteries and gastroepiploic artery. Early postoperative coronary angiography showed all the grafts patent without any stenosis. Because no atherosclerotic changes were seen in the specimens of each graft used, combined arterial grafting may have a role in the treatment of coronary artery disease in homozygous familial hypercholesterolemia.

Adult↗

PubMed1992

Transaortic patch angioplasty for left coronary ostial stenosis in a patient with Takayasu's aortitis.

A 35-year-old woman who had left coronary ostial stenosis and aortic valve regurgitation due to Takayasu's aortitis underwent transaortic patch enlargement of the stenosed left coronary ostium in combination with aortic valve replacement. This technique may be suitable and recommendable as an alternative to aortocoronary bypass grafting or endarterectomy for coronary ostial stenosis in Takayasu's aortitis.

Adult↗

PubMed1992

New side-holed sheath for intraaortic balloon pumping to maintain limb perfusion.

We developed a new side-holed shunt sheath for inserting intraaortic balloon pumps to maintain lower limb perfusion in patients with stenotic and tortuous aortoiliac arteries. This sheath has a large internal diameter and several side holes, which act as an internal shunt. It was useful and effective in 11 patients with severe aortoiliac occlusive lesions who required assistance by intraaortic balloon pumping.

Aortic Diseases↗