PubMed Health⌕ Search

Biomedical subjects

K Minami

Publications and source records attributed to K Minami.

At least 19 recordsLinked to original sources
PubMed1995

Alterations in intracellular calcium handling associated with the inverse force-frequency relation in human dilated cardiomyopathy.

BACKGROUND: The present study was performed to test the hypothesis that the altered force-frequency relation in human failing dilated cardiomyopathy may be attributed to alterations in intracellular calcium handling. METHODS AND RESULTS: The force-frequency relation was investigated in isometrically contracting ventricular muscle strip preparations from 5 nonfailing human hearts and 7 hearts with end-stage failing dilated cardiomyopathy. Intracellular calcium cycling was measured simultaneously by use of the bioluminescent photoprotein aequorin. Stimulation frequency was increased stepwise from 15 to 180 beats per minute (37 degrees C). In nonfailing myocardium, twitch tension and aequorin light emission rose with increasing rates of stimulation. Maximum average twitch tension was reached at 150 min-1 and was increased to 212 +/- 34% (P < .05) of the value at 15 min-1. Aequorin light emission was lowest at 15 min-1 and was maximally increased at 180 min-1 to 218 +/- 39% (P < .01). In the failing myocardium, average isometric tension was maximum at 60 min-1 (106 +/- 7% of the basal value at 15 min-1, P = NS) and then decreased continuously to 62 +/- 9% of the basal value at 180 min-1 (P < .002). In the failing myocardium, aequorin light emission was highest at 15 min-1. At 180 min-1, it was decreased to 71 +/- 7% of the basal value (P < .01). Including both failing and nonfailing myocardium, there was a close correlation between the frequencies at which aequorin light emission and isometric tension were maximum (r = .92; n = 19; P < .001). Action potential duration decreased similarly with increasing stimulation frequencies in nonfailing and end-stage failing myocardium. Sarcoplasmic reticulum 45Ca2+ uptake, measured in homogenates from the same hearts, was significantly reduced in failing myocardium (3.60 +/- 0.51 versus 1.94 +/- 0.18 (nmol/L).min-1.mg protein-1, P < .005). CONCLUSIONS: These data indicate that the altered force-frequency relation of the failing human myocardium results from disturbed excitation-contraction coupling with decreased calcium cycling at higher rates of stimulation.

Action Potentials↗
PubMed1995

Protein kinase C-independent inhibition of the Ca(2+)-activated K+ channel by angiotensin II and endothelin-1.

We previously reported that the Ca(2+)-activated K+ channel (KCa-channel) in cultured smooth muscle cells from porcine coronary artery was inhibited by protein kinase C (C-kinase). In this study, inhibition of the KCa-channel by receptor-mediated vascular contractile agonists, such as angiotensin II (ANG II) and endothelin-1 (ET-1), was investigated by the patch-clamp technique. In cell-attached patches, addition of ANG II (500 nM) or ET-1 (50 nM) to the bath inhibited the KCa-channel activated by the calcium ionophore A23187 (10-20 microM). Phorbol 12-myristate 13-acetate (PMA, 1 microM), a C-kinase activator, also decreased the open probability of the KCa-channel. The PMA-induced decrease in the open probability was reversed by subsequent application of staurosporine (1 nM), a C-kinase inhibitor, but the ANG II- and ET-1-induced decreases were not reversed by subsequent application of staurosporine (> 30 nM). Pretreatment of smooth muscle cells with 30 nM staurosporine, a protein kinase inhibitor, or 1 mM neomycin, an inhibitor of phospholipase C, also did not abolish the inhibition of the KCa-channel by ANG II. Furthermore, ANG II inhibited the KCa-channel in cells in which C-kinase was down-regulated. These results indicate that, in porcine coronary artery smooth muscle cells, ANG II and ET-1 inhibit the KCa-channel by a C-kinase-independent mechanism.

Alkaloids↗
PubMed1995

Ability of non-cyclic oligosaccharides to form molecular complexes and its use for chiral separation by capillary zone electrophoresis.

The binding constants (K) for complexation of the phenyl acetates with linear alpha-1,4-linked dextrins have been determined from the kinetics of the hydrolyses of the esters. The K value tends to increase with increasing the number of the glucopyranose units, suggesting hydrophobic interaction as a binding force. The weak ability of the linear dextrins to form the molecular complexes makes it possible to separate the enantiomers of binaphthyl derivatives such as 1,1'-binaphthyl-2,2'-dicarboxylic acid, 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate and 2,2'-dihydroxy-1,1'-binaphthyl-3,3'-dicarboxylic acid in their anionic forms. Hydrogen bonding as well as hydrophobic interaction is suggested as an essential force for enantioselective complexation between saccharide and anionic binaphthyl.

Carbohydrate Conformation↗
PubMed1995

[Stereotactic radiation therapy with linear accelerator: accuracy of alignment and portal film verification].

Stereotactic radiation therapy with a linear accelerator requires precise alignment of therapeutic radiation distribution to the target volume. To verify the accuracy of alignment, differences between the stereotactic coordinates of the center of the therapeutic radiation distribution determined from portal films and those of the target points determined from CT/MRI or CT/angiographic localization were calculated for 58 points. The average values and one standard deviation were--0.02 +/- 0.50mm, 0.37 +/- 0.39mm and 0.01 +/- 0.25mm in the x, y, and z directions, respectively. The average value of the total deviation was 0.73 +/- 0.07mm. Potential sources of misalignment were misaligned laser pointers, wide laser beam width, improperly zeroed target positioner scale, and motion of the patient couch. The accuracy of alignment should be verified prior to irradiation. Portal film verification is indispensable for strereotactic radiation therapy with a linear accelerator.

Cranial Irradiation↗
PubMed1994

Regulation of a non-selective cation channel of cultured porcine coronary artery smooth muscle cells by tyrosine kinase.

A non-selective cation channel was found in primary cultured porcine coronary artery smooth muscle cells. In patch-clamp studies in the cell-attached mode, this channel was activated by bath application of genistein, a specific inhibitor of tyrosine kinase, but not by daidzein, which is similar in structure to genistein but has no inhibitory effect on tyrosine kinase. This channel discriminated poorly between Na+ and K+ (permeability ratio PNa/PK = 1.03), and also transported Ca2+. The single-channel conductance measured with a pipette solution containing 150 mM Na+ was 139 +/- 24 pS (mean +/- SD, n = 5), and that for the inward current measured with 100 mM Ca2+ solution was 25 +/- 9 pS (n = 3). This non-selective cation channel was also activated by staurosporine, a non-specific protein kinase inhibitor, but not by H-7, an inhibitor of protein serine/threonine kinase. These results suggest that the activity of the non-selective cation channel is negatively regulated by tyrosine kinase activity, and thus a decrease of the enzyme activity in porcine coronary artery smooth muscle cells may result in membrane depolarization and Ca2+ entry.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Sexual transmission of hepatitis C virus among female prostitutes and patients with sexually transmitted diseases in Fukuoka, Kyushu, Japan.

The authors investigated the prevalence of antibody to hepatitis C virus (anti-HCV) in 404 female prostitutes, 428 clinic patients with a history of at least one episode of sexually transmitted disease, and 8,944 blood donors who served as the controls. All subjects were Japanese, and all studies were carried out in Fukuoka, Kyushu, Japan, in 1989. The prevalence of anti-HCV was significantly higher in the prostitutes (6.2%), in the female patients with sexually transmitted diseases (6.1%), and in the male patients with sexually transmitted diseases (2.9%) than in the controls (1.5%). Prevalence of anti-HCV increased with age in prostitutes and in the controls. The prevalence of anti-HCV in those who had been involved in prostitution for 1 year or more (8.1%) was higher than in those who had been involved in prostitution for less than 1 year (1.4%), but the difference was not statistically significant. One of the 152 anti-HCV negative prostitutes seroconverted between 1 and 2 years later. Among the subjects with sexually transmitted diseases, patients with a history of at least one episode of syphilis had a significantly higher prevalence of anti-HCV (4.4%) than the controls. Patients with acute urethritis and cervicitis also showed a high prevalence of anti-HCV (3.6% and 6.7%, respectively). These data support the possibility of sexual transmission of hepatitis C virus.

Adolescent↗
PubMed1992

Therapy for acute vascular complications in percutaneous transluminal coronary angioplasty with the autoperfusion balloon catheter.

Prolonged dilatation with an autoperfusion balloon catheter (APBC) (High-Flow-CPC-Mainz (Schneider) in 23 cases and Stack Perfusion (ACS) in 50 cases) was carried out in 73 patients (60 men, 13 women, mean age 59.3 +/- 8.8 years) with acute vascular complications occurring during PTCA (25 occlusive dissections (34%), five thrombotic occlusions (7%), 42 non-occlusive dissections (58%) and one non-occlusive thrombus with reduction of flow (1%)) in order to avoid stent implantation or emergency bypass surgery. On average 1.5 +/- 0.8 inflations were carried out per patient with a mean maximum inflation time of 14.1 +/- 8.4 min and a mean total inflation time of 16.8 +/- 12.3 min. In 61 patients (83.5%), the vascular complication could be controlled successfully with APBC, but in 12 APBC was not successful. Eight patients (11%) had emergency surgery. A stent was implanted in three patients (4.1%), and one suffered an acute myocardial infarction. Out of the 61 patients with positive result after prolonged dilatation, the hospital phase was uncomplicated in 53 (86.9%), five (8.2%) suffered an infarct with a maximum rise in CK of 350 U.l-1, two with multivessel disease had elective operations and one was dilated a second time because of a subacute reocclusion. Our experience indicates that when an acute vascular complication occurs, prolonged dilatation with an APBC is good interventional therapy avoiding stent implantation or emergency bypass surgery. However, new techniques cannot always replace surgery so an emergency bypass operation may still be necessary.

Adult↗
PubMed1992

[Detection of human papillomavirus DNA in cases of sexually transmitted diseases (STD)].

Human papillomavirus (HPV) has been detected on the genitalia without any macroscopic abnormality and the possibility of latent infection of HPV has been suggested. Using Vira Type (Toure Co.), we have detected 7 genotypes of HPV DNA under a high stringent condition on the genitalia of patients with sexually transmitted diseases (STD), who were suspected of having had many sexual partners. In male cases of STDs other than condyloma acuminatum, the HPV-positive rate of the glans and sulcus coronarius was 4.7% (5/106). In healthy men, the HPV-positive rate was 6.1% (2/33), while in chronic prostatitis cases it was 3.4% (7/205) and in benign prostatic hypertrophy cases HPV was not detected. In female cases of STDs other than condyloma acuminatum, the HPV-positive rate of uterine cervix was 5.1% (3/58). In pregnant women, the HPV-positive rate was 4.6% (9/197). With regard to the HPV-positive rate within different age groups of STD and non STD cases, the rate tended to be higher in young people. After several weeks, follow-up studies were conducted on HPV-positive cases. HPV DNA was detected in one case of 10 males STD cases and two of 10 pregnant women, and the HPV DNA was the same type as at the first examination. However, after 3-4 months, all three of these cases had become negative for HPV DNA.

DNA, Viral↗
PubMed1992

Purification, properties, and partial amino acid sequences of thermostable xylanases from Streptomyces thermoviolaceus OPC-520.

Two types of xylanases (1,4-beta-D-xylan xylanohydrolase, EC 3.2.1.8) were isolated from the culture filtrate of a thermophilic actinomycete, Streptomyces thermoviolaceus OPC-520. The enzymes (STX-I and STX-II) were purified by chromatography with DEAE-Toyopearl 650 M, CM-Toyopearl 650 M, Sephadex G-75, Phenyl-Toyopearl 650 M, and Mono Q HR. The purified enzymes showed single bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weights of STX-I and STX-II were 54,000 and 33,000, respectively. The pIs were 4.2 (STX-I) and 8.0 (STX-II). The optimum pH levels for the activity of STX-I and STX-II were pH 7.0. The optimum temperature for the activity of STX-I was 70 degrees C, and that for the activity of STX-II was 60 degrees C. The enzymes were completely inhibited by N-bromosuccinimide. The enzymes degraded xylan, producing xylose and xylobiose as the predominant products, indicating that they were endoxylanases. STX-I showed high sequence homology with the exoglucanase from Cellulomonas fimi (47% homology), and STX-II showed high sequence homology with the xylanase from Bacillus pumilus (46% homology).

Amino Acid Sequence↗
PubMed1992

Heart transplantation at the Heart Center North Rhine-Westphalia.

Since 1989, 427 heart transplants were performed at our center, limited only by donor availability, not by moderating donor criteria. Therefore, an increasing number of possible recipients was bridged with mechanical circulatory support systems. Immunosuppression was based on double-drug therapy (CsA, Aza) without steroid maintenance if possible and without mono- or polyclonal antibody prophylaxis. Monitoring adult transplant patients was based on endomyocardial biopsies only during the first 12 months posttransplant. In the pediatric group, only noninvasive diagnostic procedures were performed. Our present 1- and 3-year survival rates for heart transplant patients are 85% and 78%, respectively. We believe that only centers performing approximately 1,000 routine open-heart surgery procedures per year should be allowed to perform heart transplantation, with a minimum of 25 procedures per year (5). Our goal is to start our heart-lung and lung transplant programs in the near future. Our research interests are mainly in the field of postoperative monitoring, induction of immune tolerance, and in establishing a method to determine an individual immunosuppression protocol for each patient (6).

Academic Medical Centers↗
PubMed1992

Role of the carotid sinus in response of integrated venous system to pulsatile and nonpulsatile perfusion.

Effects of pulsatile and nonpulsatile perfusion on capacity system were investigated in 33 open-chest mongrel dogs with extracorporeal circulation. In 28 dogs with intact carotid sinus nerves, after changing from nonpulsatile to pulsatile systemic perfusion the mean arterial pressure decreased by 14 +/- 1.5 mm Hg, peripheral resistance by 423 +/- 15 dyne.cm-5.sec, and venous blood volume by 3.3 +/- 0.4 ml/kg. After changing from pulsatile perfusion to nonpulsatile systemic perfusion the mean arterial pressure increased by 15 +/- 2.2 mm Hg, the peripheral resistance by 431 +/- 15 dyne.cm-5.sec, and venous volume by 3.9 +/- 0.5 ml/kg. The same effects were observed in five dogs with bilateral isolated carotid pulsatile perfusion or nonpulsatile perfusion and systemic nonpulsatile perfusion. These effects were abolished after denervation of pressor receptors and pharmacologic blockade of alpha and beta receptors. It is proposed that with nonpulsatile perfusion carotid sinus-mediated vasoconstriction occurs in the downstream part of the capacitive system, where more pronounced wall musculature with increased number of adrenergic receptors is present. The throttle effect caused by this "resistance" part of venous circulation leads to increase of pressure in the upstream section of the capacitive system, compensates for the constrictive effect of the sympathetic tone, and leads finally to an increased volume of the capacity system. We conclude that venous response to different perfusion modalities is critically dependent on intact carotid sinus nerves and adrenergic receptors in the veins.

Animals↗
PubMed1992

Aortic valve replacement in octogenarians.

In a consecutive series of 1109 patients undergoing aortic valve replacement (AVR) between January 1988 and December 1990, there were 48 patients (33 female, 15 male) over 80 years of age (mean age 83.5 years, median 82.9 years). Of those, 33 had aortic stenosis and 15 combined aortic valve disease, with additional coronary artery disease being present in 36. Isolated AVR was performed in 25 patients, and it was combined with coronary venous bypass grafting, with 1-4 (mean 1.8) peripheral anastomoses in 23. Two patients died within 30 days (early mortality 4.2%). Non-fatal complications included one hemiparesis, four transient cerebral disorders, two cases of pneumonia which led to ventilatory assistance, three rethoracotomies because of postoperative bleeding, 15 tachycardias and one transient AV block. Late results were obtained after a median follow up time of 22 months. There were eight late deaths (four cardiac related, four not related) and a low incidence of non-fatal complications (two episodes of gastrointestinal bleeding while on oral anticoagulation, one cerebral transient ischemic attack and one acute left ventricular failure). Nine patients are in NYHA Class I, 12 in Class I-II, 11 in Class II, three in Class II-III and three in Class III. Of the surviving 38 patients, four are currently living in a home for the aged or a nursing home, while all the others are living in their own homes and are able to sustain a relatively independent life-style. We conclude that in very old patients with aortic valve disease, AVR can be performed with low mortality and few non-fatal complications.

Aged↗
PubMed1992

[A study of DNA ploidy pattern, proliferation index and PCNA in duodenal carcinoma].

12 cases of duodenal carcinoma were studied for nuclear DNA ploidy patterns, the proliferation index (PI), proliferating cell nuclear antigen (PCNA) positive score (1 = 0-25%, 2 = 26-50%, 3 = 51-75%, 4 = 76-100%) and PCNA positive rate. DNA aneuploidy was observed in 9 cases (75%) and PCNA staining was positive in 11 cases (91.6%). DNA ploidy patterns, PI, PCNA positive scores and positive rates were not related to each other. No relationship DNA ploidy patterns for PCNA positive scores and PCNA positive rates could be found. The relationship between PI and PCNA positive score was found not to be significant (P less than 0.10). PI was revealed to correlate significantly (P less than 0.05) to PCNA positive rate.

Aneuploidy↗