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Biomedical subjects

K Sumimoto

Publications and source records attributed to K Sumimoto.

At least 55 records · Page 3Linked to original sources
PubMed1992

Clinical use of synthetic absorbable cuff material for peripheral vascular anastomosis.

End to end arteriovenous (AV) fistulas were created using the cuff technique for hemodialysis in 12 patients with end stage renal disease. The cuff used was made of a synthetic biodegradable material, a lactic glycolic acid co-polymer with the same composition as absorbable surgical suture. Cephalic vein radial artery fistulas in the forearm were created electively in six patients to convert a Scribner shunt to a fistula in three patients and because of malfunction of a fistula created previously in three patients. Eleven patients underwent hemodialysis, with pump speeds of more than 200 milliliters per minute, and were evaluated for 129 to 477 days. These subcutaneous AV fistulas were maintained as patent functional veins and continued to function without complication. After five weeks, one patient had conversion to a prosthetic AV fistula because of poor venous maturation. The overall patency rate was 92 percent. The diameter of the AV anastomosis increased gradually with time. At 20 weeks, however, it reached more than 70 percent of the diameter of the radial artery lumen. These observations led us to believe that the cuff material used is biodegraded until 20 weeks and gives sufficient flexibility. In the future, the cuff method is expected to be clinically developed as another approach for vascular anastomosis.

Adult↗
PubMed1992

Determining zinc coproporphyrin in maternal plasma--a new method for diagnosing amniotic fluid embolism.

We measured the concentration of zinc coproporphyrin I (ZnCP-I), a characteristic component of meconium, in maternal plasma by fluorometry after HPLC. We obtained plasma samples from 89 women: 35 at weeks 10-40 of normal pregnancy, 41 shortly after normal delivery, 4 from patients with amniotic fluid embolism (AFE), and 9 from non-AFE patients with intra- or postpartum shock caused by genital bleeding. The plasma ZnCP-I concentration was 97 (SD 83, range 38-240) nmol/L in the AFE patients, 11 (SD 9.2) nmol/L in the non-AFE patients, 12 (SD 7.9) nmol/L during normal pregnancy, and 26 (SD 10) nmol/L shortly after normal delivery. We suggest that measuring ZnCP-I in maternal plasma by fluorometry on HPLC is a rapid, noninvasive, and sensitive method for diagnosing AFE and propose 35 nmol/L as the cutoff value for the ZnCP-I concentration in maternal plasma for the diagnosis of AFE.

Adult↗
PubMed1991

Isolation and characterization of zinc coproporphyrin I: a major fluorescent component in meconium.

We isolated a substance from an organic extract of meconium (in neutral pH) that exhibited a porphyrin-like fluorescence peak at 580 nm on excitation at 405 nm and deduced its structure. Spectrometric data suggest that the substance is not free coproporphyrin I or free coproporphyrin III, but is a chelate of coproporphyrin I with Zn2+. We also detected a chelate of coproporphyrin III with Zn2+ by HPLC. These substances may be useful as new indicators of the presence of meconium.

Amniotic Fluid↗
PubMed1990

[Study on the specific diagnosis of meconium aspiration syndrome (MAS) with fluorometry].

Porphyrins are found in fetal urine, neonatal urine, amniotic fluid, and meconium. Zn-coproporphyrin (Zn-CP), which we identified in meconium, has two fluorescent peaks at 580 nm and 630 nm, and Coproporphyrin (CP), found in fetal urine, has one fluorescent peak at 620 nm, when both porphyrins are excited at 405 nm. In this study, the fluorescent peak at 580 nm was used to detect Zn-CP in neonatal urine, using the new index, that is the Urinary Fluorescence Meconium Index (UFMI); UFMI = F580-(F580 + F600)/2 [F: fluorescence intensity]. We obtained urine samples from neonates in these three groups: Group-I: Meconium Aspiration Syndrome (MAS; n = 3), Group-II: non-MAS with meconium stained amniotic fluid at delivery (n = 18), and Group-III: non-MAS with clear amniotic fluid at delivery (n = 25). The UMI (Urinary Meconium Index) was also measured by conventional optical absorbance. The results show that many false positive cases were observed in UMI, and that no false positive cases were observed in UFMI. These results lead one to speculate that Zn-CP, which is specific in meconium, is used in UFMI measurement, while UMI measurement by absorbance cannot exclude contamination by CP in neonatal urine, so Zn-CP and CP are measured all together. UFMI values reflected the clinical course of neonates. It is concluded that UFMI is a more sensitive method than UMI for the diagnosis of MAS.

Coproporphyrins↗
PubMed1989

Actions of a newly synthesized nitro-compound, E-4701, on rabbit vascular smooth muscles.

The effects of a newly synthesized water soluble and light resistant nitro-compound, E-4701, on the electrical and mechanical properties of smooth muscle cells of rabbit mesenteric and coronary arteries were investigated. In the endothelium-denuded rabbit mesenteric artery, E-4701 relaxed the tissue pre-contracted by noradrenaline (IC50 = 40 microM) to a greater extent than that contracted by high K, but to a lesser extent than that contracted by acetylcholine (ACh) or high K in endothelium-denuded rabbit coronary artery (the IC50 was 20 nM or 60 nM, respectively). Nitroglycerin showed much the same relaxing action on the above tissue (IC50 for the ACh- or K-induced contraction was 20 nM or 65 nM, respectively). Relaxing actions of E-4701 or nitroglycerin were prevented by 10 microM methylene blue. In muscle cells of the porcine coronary artery, E-4701 or nitroglycerin inhibited the Ca-transient provoked by ACh, as examined using fura-2. Both drugs had no effect on the Ca-induced contraction in skinned muscle strips. ACh produced a transient hyperpolarization with subsequent depolarization, but in the endothelium-denuded tissues. ACh only depolarized the membrane. E-4701 inhibited the ACh-induced depolarization, but nitroglycerin did not. We concluded from our observations that E-4701 has the typical characteristics of a nitrocompound with an inhibitory action on the agonist-induced membrane depolarization.

Acetylcholine↗
PubMed1989

[Field trial of the early detection in patients with ovarian cancer].

We measured the six tumor markers, CA125, TPA, Fr, CEA, AFP, and PPA simultaneously in serodiagnostic testing as a method for the early detection of ovarian cancer. To decrease the false negativity in the combination assay, statistical discriminating analysis was applied to serum values for tumor markers. "The ovarian cancer screening test" designed by us has been enforced in Shizuoka Prefecture since September, 1985. Twenty-one thousand nine hundred serum samples had been analysed by December, 1988. Eighty-four cases out of the 125 patients with ovarian cancer were suspected of being malignant pretherapeutically in a clinical diagnostic procedure which included echography. On the other hand, malignancy was justified before treatment in 109 patients in the combination assay and statistical analysis. One hundred patients were diagnosed as malignant in the combination assay and 9 cases by statistical analysis. However, we overlooked 4 patients (3 patients were found to be in stage I and one in stage III, respectively) even when both methods were used. Altogether 37 more patients with ovarian cancer could be found by the serodiagnostic screening method with discriminating analysis using tumor markers than by clinical findings such as image diagnosis and others. To conclude, the discriminating analysis was, therefore, verified as a useful technique for the diagnosis of ovarian cancer.

Adult↗
PubMed1989

[Serodiagnostic tests by factor analysis and stepwise discriminating analysis with tumor markers for the detection of ovarian cancer].

We measured five tumor markers simultaneously for serodiagnostic testing as a method for the early detection of ovarian cancer. To decrease both false negativity and false positivity in the results of combination assay, statistical analysis including factor analysis and stepwise discriminating function was applied in this study. At least one of these tumor markers was detected as positive in 75.2% (76 of 101 patients) of sera from patients with ovarian cancer before treatment. Six hundred and ninety-three of 7,097 normal sera (9.8%) gave spuriously positive combination assay results. Falsely positive combination assay results were observed in 1,107 of 3,139 patients with benign disease, which could largely be attributed to the high CA125 values in patients with endometriosis. On the basis of factor analysis in order to decrease false positivity, CA125, TPA, and CA125/TPA were selected as the best parameters for distinguishing between ovarian cancer and benign conditions including those pelvic endometriosis showing positive results in combination assays. Subsequently, the function derived by factor analysis made possible the correct classification of 58 of 71 patients with ovarian cancer detected by combination assay, and 84.8% of pelvic endometriosis and benign ovarian tumor subjects were correctly classified into the non-cancer group. Next, in order to decrease false negativity, statistical analysis was also applied. Malignancy could be correctly diagnosed by this procedure in 14 of 25 patients whose tumor was undetectable by combination assay, whereas of subjects without cancer 14.5% were errorenously classified into the ovarian cancer group. In the search for the best method for accurately detecting ovarian cancer, we used image diagnosis (ultrasonography) in combination with serological diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Diagnostic value of serological tumor marker tests in patients with ovarian cancer].

The usefulness of tumor markers in serodiagnosis of cancer designed to detect ovarian cancer at an early stage was evaluated from the point of view of their diagnostic value. Namely, eight tumor markers, CA125, SLX, CA72-4, TPA, Fr, CEA, CA19-9, and SCC, were determined and studied to find the combination that would yield the optimal diagnostic value. For this purpose, the diagnostic value was calculated from sensitivity x specificity. As a single tumor marker CA125 proved optimal with a diagnostic value of 0.50. The higher value, 0.53, was obtained as the diagnostic value from the combination of two tumor markers, CA125 and CA72-4. When three tumor markers were combined, CA125, CA72-4 and SLX gave an optimal diagnostic value of 0.65. In the combination of four tumor markers, CA125, CA72-4, SLX and CA19-9 gave a diagnostic value of 0.63. In the five marker combination CA125, CA72-4, SLX, CA19-9 and TPA worked well and had a diagnostic value of 0.59. When the markers were increased to six types, CA125, CA72-4, SLX, CA19-9, TPA and Fr provided a combination with 0.53 as the diagnostic value. In the seven marker combination CA125, CA72-4, SLX, CA19-9, TPA, Fr and CEA gave a diagnostic value of 0.51. The efficiency declined to 0.51 when eight tumor markers were combined. When cost performance in the measurement of tumor markers for early detection of ovarian cancer is taken into account, a dilemma arises in that the increase in the number of tumor markers used is accompanied by higher sensitivity and lower specificity.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Neoplasm↗
PubMed1988

Reliable indices for the determination of viability of grafted liver immediately after orthotopic transplantation. Bile flow rate and cellular adenosine triphosphate level.

One of the major problems accompanying liver transplantation is how to evaluate the viability of the grafted tissue at an early stage. The ability to assess immediate graft function would provide results useful in the determination of prognosis. The present study was undertaken to determine whether bile flow rates after liver transplantation were correlated with adenosine triphosphate levels and the survival of rats given transplants. In fresh-liver-transplanted rats, the one-week survival rate was 87%. The cellular ATP levels in the grafts decreased sharply prior to portal-venous declamping, but returned to nearly 80% of the normal level 4 hr after grafting, as did the total adenine nucleotide level and energy charge. When the grafts were subjected to warm ischemia for 15-min or 30-min periods prior to harvesting of the donor liver, the one-week survival rates decreased to 50% and 0%, respectively. In these cases, the levels of cellular ATP and bile secretion remained low and were proportional to the survival of the transplanted animals even 4 hr after transplantation. The relationship between the bile flow rates and the cellular ATP levels under various conditions revealed a good correlation, showing a saturation curve. The bile flow rates as well as the cellular ATP levels were therefore related to the survival rates of the transplanted animals. Thus it was shown in this experimental transplantation model that the monitoring of bile production after liver grafting is a useful indicator for assessing the extent of ischemic damage to the liver and for prognosis of the animal.

Adenosine Triphosphate↗
PubMed1988

Relaxing actions of procaterol, a beta 2-adrenoceptor stimulant, on smooth muscle cells of the dog trachea.

1. The effects of procaterol, a beta 2-adrenoceptor agonist, on smooth muscle cells of the dog trachea were investigated by use of microelectrode and isometric tension recording methods, and by measurement of Ca transients as estimated from the fura-2 fluorescence, adenosine 3':5'-cyclic monophosphate (cyclic AMP) and breakdown of phosphatidylinositols. 2. Procaterol hyperpolarized the membrane and increased the ionic conductance (above 10 nM) in a dose-dependent manner. These actions were inhibited by propranolol. 3. Procaterol inhibited the mechanical responses evoked by acetylcholine (ACh), histamine or 5-hydroxytryptamine (5-HT), in the presence or absence of Ca2+ in the bath solution, but not that evoked by high concentrations of ACh (1 microM). The ID50 value of procaterol for the peak amplitude of the ACh-induced contraction (30 nM) was 0.3 nM. The equivalent values for the histamine-induced phasic and tonic responses (10 microM) were 0.15 and 0.01 nM), respectively. 4. Procaterol (over 1 nM) increased the amount of cyclic AMP in a dose-dependent manner which was blocked by prior application of propranolol. 5. Procaterol did not alter the changes in the amounts of phosphatidylinositol 4,5-bisphosphate (PI-P2) and phosphatidic acid (PA) induced by ACh, histamine or 5-HT. Thus, the synthesis of inositol 1,4,5-trisphosphate is not affected by stimulation of the beta 2-adrenoceptor. 6. ACh increased the free Ca2+ concentration to a greater extent than that produced by histamine or 5-HT. These changes were reduced by procaterol, except for those induced by high concentrations of ACh (over 1 microM). 7. It is concluded that procaterol relaxes tissues precontracted by various agonists due to a reduction in the free Ca2+. This inhibitory action may be due to an increase in the amount of cyclic AMP but does not result from an inhibition of the hydrolysis of phosphatidyl inositols. The hyperpolarization induced by procaterol may partly contribute to the observed relaxation.

Adrenergic beta-Agonists↗
PubMed1988

Characterization of [3H]nifedipine binding to intact vascular smooth muscle cells.

Specific binding of the dihydropyridine Ca2+ antagonist [3H]nifedipine to dispersed smooth muscle cells of the porcine coronary artery was investigated and the findings were compared with the binding to microsomes of smooth muscles. Specific binding to intact cells was saturable and reversible. The dissociation constant was 1.93 +/- 0.42 nM and the maximal binding capacity was 59.6 +/- 12.4 fmol/10(6) cells, as assessed by Scatchard analysis of the equilibrium binding at 25 degrees C. The Kd value with intact cells was slightly higher than that observed with microsomes. Specific binding of [3H]nifedipine to intact cells was completely displaced by unlabeled dihydropyridine derivatives. Among other Ca2+ antagonists, verapamil and d-cis-diltiazem partially and flunarizine completely inhibited the binding. In the case of microsomes, d-cis-diltiazem stimulated the binding of [3H]nifedipine. These results suggest that there may be multiple binding sites for different subclasses of Ca2+ antagonists. Polyvalent cations had no effect on the binding to intact cells. In the case of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)-treated microsomes, the addition of CaCl2 and BaCl2 increased the Bmax, but the Kd value remained unchanged. MnCl2 and CdCl2 had stimulatory or inhibitory effects, depending on the concentrations, whereas LaCl3 had no effect. The effect of membrane depolarization on the binding was also examined. When the intact cells were incubated in high [K+]o solution for 60 min, the Kd was lowered to 1.4 nM from the control value of 2.0 nM, thereby indicating that [3H]nifedipine binds to Ca2+ channels, with a higher affinity, at depolarized states.

Animals↗