Biomedical subjects

H Mohri

Publications and source records attributed to H Mohri.

At least 145 records · Page 8Linked to original sources

PubMed1993

Single-dose effect of enteric-coated aspirin on platelet function and thromboxane generation in middle-aged men.

OBJECTIVE: To evaluate the effect of a single dose of enteric-coated aspirin (ECA) in three different dosages on platelet function and thromboxane generation in middle-aged men. DESIGN AND METHODS: In a nonblind, nonplacebo-controlled, crossover study, a single dose of ECA (50, 250, or 1000 mg) was given in a tablet form to a group of healthy, middle-aged men. Ten subjects, aged 50-67 years, volunteered to participate in this study. Platelet functions including bleeding time, platelet aggregation, adenine nucleotides, beta-thromboglobulin, platelet factor 4, thromboxane generation, and aspirin measurement were determined. RESULTS: Before ECA ingestion, the intracellular adenine nucleotides (adenosine triphosphate, adenosine diphosphate) were decreased, and both beta-thromboglobulin and platelet factor 4 were increased. These observations suggested that platelets were activated in vivo in middle-aged men. These findings returned to normal within 8 hours after the ingestion of ECA, and maintained normal for at least two days. Bleeding time was significantly prolonged at 8 and 24 hours compared with that before ingestion of ECA 1000 mg (p < 0.05). The generation of platelet thromboxane was maximally inhibited by approximately 40 percent in the samples 8 hours after ECA ingestion. Abnormal values of adenine nucleotides, beta-thromboglobulin, and platelet factor 4 returned to normal within 8 hours. Arachidonic acid-induced platelet aggregation was inhibited compared with that before treatment (p < 0.01) and the inhibitory effect was maintained for at least three days. Adenosine diphosphate- and epinephrine-induced aggregations were less inhibited than those induced by arachidonic acid. Inhibitory effects of ECA on platelet aggregation were dose dependent. CONCLUSIONS: Our study indicates that platelets are activated in middle-aged men and that a single dose of ECA 50 mg is safe and can inhibit thromboxane synthesis and platelet aggregation. These results suggest that a daily dose of ECA 50 mg may be useful for blocking platelet activation and preventing thrombosis.

Aged↗

PubMed1993

Changes in the cytoskeletal structure of cultured smooth muscle cells induced by calyculin-A.

Changes in the cytoskeletal structure of cultured A10 smooth muscle cells induced by calyculin-A (CL-A), a potent inhibitor of types 1 and 2A protein phosphatases, were analyzed using indirect fluorescence techniques. In the presence of 1 x 10(-7) M CL-A the cells became round and subsequently detached from the substratum. The effect of CL-A was inhibited by a non-selective kinase inhibitor, K-252a, but not by EGTA. In rounded cells stress fibers were absent and staining for F-actin appeared in patches. Vinculin, one of the components of focal contacts, was localized at the periphery of control cells. CL-A treatment moved the focal contacts towards the inside of the cell along the stress fibers, and this was followed by the rounding up of the cell. In addition, rapid and marked changes in microtubule structure were observed in CL-A-treated cells. Many 'nicks' or 'gaps' were observed along the microtubules in the attached, spread cells. A filamentous network of microtubules was not observed in the detached cells, i.e. after longer exposure to CL-A. These results suggest that CL-A may change the structure of focal contacts, resulting in the rounding up of the cell, and inducing a microtubule-severing activity. These effects were independent of the external Ca2+ concentration. The changes in cytoskeletal structure may be caused by disturbing the balance of phosphorylation and dephosphorylation in the cell.

Actin Cytoskeleton↗

PubMed1993

Lipid composition of hamster epididymal spermatozoa.

The lipid composition of hamster epididymal spermatozoa was examined. Caput epididymal spermatozoa were isolated by Percoll density gradient centrifugation without contamination by other cells and they had a specific gravity of 1.10-1.12 g cm-3. Caput and cauda epididymal spermatozoa showed little difference in the amounts of total fatty acid and total sterol. However, sterol composition changed markedly during the transit of spermatozoa through the epididymis: the amount of cholesterol decreased, while the amount of desmosterol and cholesta-7,24-dien-3 beta-ol increased. No significant change in fatty acid composition was observed during the transit, although there was a tendency for an increase in chain length. Both 22:5 and 22:6 represented high percentages in fatty acids of hamster spermatozoa. Some difference in lipids was detected between the upper fraction (1.04 g cm-3) and the lower fraction (1.10 g cm-3) obtained by the density gradient centrifugation of cauda epididymal spermatozoa. Total fatty acid content of the upper fraction was 1.4-fold higher than that of the lower fraction, and the percentage of 18:0 was lower in the latter fraction with a higher percentage of 18:2. The total sterol:total phospholipid ratio in hamster cauda epididymal spermatozoa was 0.21.

Animals↗

PubMed1993

Acute hemodynamic changes after Fontan operation: an experimental study.

Seven adult mongrel dogs with an average body weight of 11.3 kg were subjected to experimental Fontan operation in order to evaluate acute hemodynamic changes at the Fontan circulation. The Fontan circulation was established by occlusion of the tricuspid valve with tightening a purse-string suture which was placed around the valve under inflow occlusion and was passed through the anterior right atrial wall, and by connection with a 10 mm Gore-Tex graft between right atrium and pulmonary artery. When the Fontan circulation was established, aortic pressure and cardiac output (CO) decreased from 94.9 +/- 22.0 mmHg to 41.9 +/- 6.0 mmHg and 0.907 +/- 0.179 liter/min to 0.259 +/- 0.072 liter/min, respectively. There were no significant changes in heart rate and systemic vascular resistance between normal and the Fontan circulations. On the other hand, pulmonary vascular resistance (PVR) increased from 11.6 +/- 7.3 units in the normal circulation to 21.8 +/- 13.0 units in the Fontan circulation. From this study it was concluded that main changes in hemodynamic parameters immediately after establishing the Fontan circulation were marked decrease in systemic arterial pressure and CO, and an increase in PVR. Therefore, one should consider a possibility of an increase in the PVR to the critical level when the Fontan operation was applied to patients with pulmonary hypertension.

Animals↗

PubMed1993

Risk analysis of low cardiac output syndrome after valve replacement.

In order to obtain a better understanding of the pathogenesis of the postoperative low cardiac output syndrome (LOS), a multivariate regression analysis was performed, evaluating predictive risk factors quantitatively as a function of plural preoperative variables. A total of 145 cases including 76 MVR (MS 36 MR 40), 42 AVR and 27 DVR were analyzed in this study. Ten historical, 10 hemodynamic and 4 operative risk factors were collected to compose the data file with corresponding status of postoperative cardiac function which was classified as follows. Patients who were not associated with postoperative LOS (Score 1), associated with the LOS which required and responded to ordinal dosage of a catecholamine (Score 2) associated with the LOS which required and responded to maximal dosage of the catecholamine and/or mechanical circulatory support (Score 3), and died of LOS (Score 4). Variables with significant relationships to postoperative LOS, regression equation to LOS score and their multiple correlation coefficients (R) of each group were as follows. MVR group: technical trouble (TT), extracorporeal circulation time (ECCT), change of myocardial preservation methods, delta LVSWI/delta LVEDP, diseased duration, aortic cross clamping time, CTR, Y = -1.16 + 1.01 (TT) + 0.05(ECCT) + 0.16(delta LVSWI/delta LVEDP) + 0.02(CTR), R = 0.76. AVR group: LVMMI, ECCT, cardiac failure, NYHA, Y = -0.71 + 0.03(LVMMI) + 0.004 (ECCT) + 0.22(NYHA), R = 0.78. DVR group: delta LVWI/delta LVEDP, LVMMI, NYHA, LV diastolic eccentricity ratio, ECCT, Y = -0.50 + 0.60 (delta LVWI/delta LVEDP) + 0.003(LVMMI) + 1.18(NYHA) + 0.38(delta LVSWI/delta LVEDP) + 0.003(ECCT), R = 0.87. It was demonstrated that preoperative ergometer exercise study during cardiac catheterization was useful in prediction of postoperative outcomes, especially in the MVR (MS) group.

Adult↗

PubMed1993

Pulmonary vascular disease and operative indications in complete atrioventricular canal defect in early infancy.

Pulmonary vascular disease was morphometrically analyzed in 67 patients (mean age, 19 months) with isolated complete atrioventricular canal defect. Complete obstruction of the small pulmonary arterial lumen resulting from acute fibrous proliferation and atrophy of the peripheral arterial media, which were considered absolute operative contraindications, were characteristic in six patients with Down's syndrome. Morphometric analysis of medial thickness revealed that thinning of the media of the small pulmonary arteries is generally observed at around 6 months of age in patients with complete atrioventricular canal defect and that the media in patients who have complete atrioventricular canal defect and Down's syndrome was thinner than that in such patients without Down's syndrome. These results suggest that thinning of the media as a result of two factors--Down's syndrome and aging--facilitates the rapid occurrence of fibrous intimal proliferation. Therefore intracardiac repair is desirable within 6 months of life, before medial thinning, in patients with complete atrioventricular canal defect and Down's syndrome. Excluding patients with absolute operative contraindications, the scores of the index of pulmonary vascular disease in operative survivors were below 2.0 and death occurred when scores were more than 2.2. The pulmonary vascular resistances measured in room air and by the oxygen inhalation and tolazoline tests in patients with operative contraindications were more than 7.3, 3.8, and 6.6 units.m2, respectively. We thus conclude that lung biopsy should be undertaken for patients in whom pulmonary vascular resistance is beyond these values to determine the appropriateness of surgical intervention.

Child↗

PubMed1993

Multivariate analysis of risk factors for thrombus formation in University of Tokyo ventricular assist device.

Of 77 University of Tokyo ventricular assist devices used in a total of 70 patients at 21 institutions, 13 pumps were found to have macroscopic thrombus formations. Because 19 devices that were used for less than 24 hours showed no thrombus deposition, they were considered not to have been sufficiently exposed to the thrombogenic environment for macroscopic thrombus deposition and were removed from the subsequent multivariate study. A total of eight potential risk factors were assessed in relation to thrombosis. Prevalences of thrombus formation were compared between two groups with or without each of the risk factors. In a univariate analysis, the following categoric variables were demonstrated to be significantly associated with complications, in descending order of significance: use of gabexate mesilate (protease inhibitor) as an anticoagulant (p = 0.005), normal platelet count (p = 0.010), duration of support (p = 0.038), leukocytosis (p = 0.042), and minimum pumping flow (p = 0.042). Use of heparin and the consequent increase in activated clotting time showed no relationship. Multivariate discriminant analysis, which was done to identify risk factors rejecting cross correlation between each variable, demonstrated platelet count (p = 0.006), use of gabexate mesilate (p = 0.007), and minimum flow (p = 0.008) to have significant and independent risks. These results indicate the importance of maintaining pumping flow above a certain minimum level, addition of antiplatelet drugs to the antithrombogenic regimen, and nonuse of gabexate mesitate.

Adolescent↗

PubMed1993

[Neutrophilic myelofibrosis; a case report].

A 53-year-old male was admitted to our hospital with abdominal pain. Physical examination revealed marked splenomegaly. The white blood cell count increased to 5.8 x 10(4)/microliters. Bone marrow biopsy showed hypercellularity with a moderate increase in reticulin fiber. Chromosomal analysis showed 47, XY, +9q-, -9q- without Ph1 chromosome and bcr-abl rearrangement. MCNU therapy was successful in reducing the white blood cell count and splenomegaly. It is likely that the diagnosis of our patient is compatible with the neutrophilic myelofibrosis described by Stewart, et al.

Blood Cell Count↗

PubMed1993

Sound spectral analysis of prosthetic valvular clicks for diagnosis of thrombosed Björk-Shiley tilting standard disc valve prostheses.

To evaluate clinical usefulness of sound spectral analysis in the early detection of prosthetic thrombosis, we analyzed specific patterns of thrombus formation in Björk-Shiley tilting standard disc prostheses in relation to the sound spectral analysis of their click sounds. Among a total of 365 Björk-Shiley tilting standard disc prostheses, nine became thrombotic. These consisted of seven prostheses in the mitral position and two in the aortic position, and the affected valves were replaced in all cases. The sound spectral analysis system includes a wide-frequency microphone and a sound spectral analyzer. To quantify the amplitude of the metallic clicks that are specific to the prosthetic valve sounds, we used a normalized maximal frequency as a diagnostic parameter for valve thrombosis. Thrombus formation was localized at the minor strut in two cases, and these demonstrated abnormally low normalized maximal frequency values only on opening clicks. In four cases thrombus formations were noted at both minor and major struts, and these showed abnormally low normalized maximal frequency values on both opening and closing clicks. In two cases with pannus formation, no abnormalities were found by sound spectral analysis. In one case, which had demonstrated abnormally decreased normalized maximal frequency values of both opening and closing clicks, the normalized maximal frequency values were normalized after thrombolytic therapy, suggesting resolved thrombosis. Reoperation, which was performed for concomitant complication of perivalvular leak, revealed no noticeable thrombus formation. The thrombi were seen on the minor strut during surgical procedures in all cases in which valve thrombosis was indicated by the sound spectral analysis. Therefore, the minor strut is considered to be the prevalent area of thrombus formation, and diagnosis could be made after observation of abnormally low normalized maximal frequency on opening clicks. We found the sound spectral analysis to be an extremely useful diagnostic tool for early detection of thrombosis in the Björk-Shiley tilting standard disc prostheses, especially because the opening clicks of the tilting disc valve were too low in amplitude for auscultation to detect the existence of mild abnormality.

Adolescent↗

PubMed1993

[Airway hyperreactivity test by measurement of specific airway conductance during quiet breathing].

In asthmatic patients, the threshold for specific airway conductance during quiet breathing (sGawqt) in the airway hypersensitivity test was determined using our newly developed pressure corrected flow type body plethysmograph and compared with that measured by means of respiratory resistance (Grs) Astograph in relation to the following parameters: 1) Dmin, an index of airway sensitivity (accumulated methacholine concentration at the time of onset of linear decrease in the dose-response curve), 2) SsGawqt and SGrs, indicators of airway sensitivity (slope when the value begins to decrease) and 3) PD35 (accumulated methacholine concentration when the valve has decreased to 35% of the initial value). Although no significantly difference was observed in SsGawqt and SGrs, significantly lower values of Dmin and PD35, indexes of airway sensitivity, were obtained with sGawqt method as compared to Astograph. These findings may indicate that the airway hypersensitivity test using our body plethysmography technique can be performed using a smaller amount of inhaled methacholine with less patient burden as compared to Astograph.

Adult↗

PubMed1993

[Continuous irrigation followed by combined omental transposition and pectral muscle rotation for treatment of postoperative mediastinitis with DIC in a child].

A 8-year-old boy was complicated with mediastinitis with DIC 20 days after replacement of the stenotic right ventricular outflow conduit. Open drainage and débridement were performed and semi-closed continuous irrigation with 1% povidone iodine was continued for 10 days to control DIC. Thereafter, the pedicled omentum was mobilized to the upper anterior mediastinum, however, it was too thin to obliterate there. To obliterate the upper anterior mediastinum and cover the infected graft, the major pectoral muscle flap was introduced to the anterior mediastinum through the window created by removing a part of left second rib. The sternum was closed primarily. The postoperative course has been well and no recurrence has been proved for 1 year.

Cardiac Surgical Procedures↗

PubMed1992

Low-dose cytosine arabinoside for treating hypocellular acute leukemia in the elderly.

Ten previously untreated elderly patients with hypocellular acute leukemia received a low dose of cytosine arabinoside (Ara-C), 10 mg/m2 injected subcutaneously every 12 hours for 14-28 days. Six patients achieved a complete remission (CR) for periods ranging for 6-23 months (median 8.5 months) and the others had a partial remission (PR). Relapse has occurred in three patients to date. The median survival ranged from 10-24 months (median 14.5 months). Only two of the six patients, in whom bone marrow biopsy was performed at CR, had a normal cellularity. This change, however, did not appear to be a significant prognostic factor in those patients. In seven patients who achieved a CR or PR low-dose Ara-C was administrated as maintenance therapy at the same low dose for 10 days each month. Treatment was well tolerated in all patients despite for myelosuppression. There were no drug-related deaths. These observations suggest that low-dose Ara-C is effective in treating elderly patients with hypocellular acute leukemia.

Acute Disease↗

PubMed1992

Purification and characterization of a sperm motility-dynein ATPase inhibitor from boar seminal plasma.

A sperm motility inhibitor from boar seminal plasma was purified. The purification procedure included dialysis against 0.1 M Tris-HCl containing 0.1 mM DTT and chromatographies on SP-Sephadex C-25 and Phenyl-Sepharose CL-4B. With this procedure, the seminal plasma motility inhibitor (SPMI) preparation was highly purified with a 18% recovery of inhibitory activity. The molecular weight of SPMI in native conditions has been estimated at 50,000 by molecular sieving, but 3 polypeptides with molecular weights of 14,000, 16,000 and 18,000 were observed following polyacrylamide gel electrophoresis in denaturing conditions. SPMI is a thermolabile basic protein that is stable between pH 6 and pH 11. The observations that SPMI effects on motility of demembranated spermatozoa are reversed by Mg.ATP and that SPMI inhibited bull dynein ATPase in a concentration-dependent manner suggest that this protein blocks the motility of demembranated spermatozoa by interfering with dynein arm function.

Animals↗

PubMed1992

Permanent pacemaker implantation in premature infants less than 2,000 grams of body weight.

Pacemaker implantation in premature infants presents technical problems because of the relatively larger size of the pulse generator compared with their bodies. A new technique with which successful generator implantation was performed in 2 premature infants less than 2,000 g of body weight is described. The generator is wrapped in a Gore-Tex surgical membrane. A piece of membrane overlying the electrical contact surface of the generator is removed, and the generator is fixed to the abdominal wall in the peritoneal cavity. The technique is simple to perform and would give relative ease in generator exchange.

Birth Weight↗

PubMed1992

Thoracic aortic operations in patients aged 70 years or older.

Thirty-one patients over the age of 70 years (group A) and 72 patients less than 69 years (group B) underwent a variety of thoracic aortic surgical procedures. Early and long-term results and cerebral function were compared between the two groups. Preoperative and postoperative cerebral function was evaluated using mini mental state-Himeji and Wechsler adult intelligence scale tests. The operative mortality of groups A and B was 12.9% and 11.1%, respectively (not significant). There were no significant differences in postoperative complications between the two groups. The late mortality rates of groups A and B were 11.1% and 9.3%, respectively (not significant). There were no significant differences between the two groups in the mini mental state-Himeji test, digit symbol, vocabulary, and total Wechsler adult intelligence scale scores before and after operation. We conclude that thoracic aortic surgical procedures in patients over 70 years of age can be performed with acceptable mortality and morbidity risks. Most patients showed symptomatic improvement.

Adult↗

PubMed1992

Late results after repair of complete atrioventricular canal.

Twenty-five patients with complete atrioventricular canal including 10 Down's syndrome patients repaired since 1972 were analyzed with respect to their physical activities, hemodynamics, ECG, reoperation and late mortality. Follow-up period ranged from 1 to 17 years with an average of 7.0 years. There was 1 late death. Actuarial survival rate was 0.86 +/- 0.13 (mean +/- S.D.) at 12 years. Fourteen patients (70%) of 20 evaluated were in New York Heart Association functional class I, and 4 (20%) were in class II and 2 (10%) in class III. In 23 patients without pulmonary stenosis, preoperative values of peak pulmonary to systemic pressure ratio (Pp/Ps) and pulmonary to systemic arterial resistance ratio (Rp/Rs) were 0.64 +/- 0.28 and 0.36 +/- 0.31, respectively. Postoperative Pp/Ps and Rp/Rs significantly decreased to 0.37 +/- 0.14 and to 0.20 +/- 0.14, respectively. In Down patients, postoperative Pp/Ps, Rp/Rs and pulmonary arterial resistance were significantly greater than in non-Down patients (0.50 +/- 0.07 vs. 0.25 +/- 0.05, 0.30 +/- 0.13 vs. 0.10 +/- 0.03 and 4.4 +/- 1.8 vs. 1.8 +/- 0.6 units.m2, respectively). Complete heart block developed in 1 patient postoperatively. Sick sinus syndrome was observed in 3 patients, transient Mobitz II A-V block in 2, ventricular premature contractions of Lown's Grade II in 1 and atrial fibrillation in 1. Five patients demonstrated severe mitral regurgitation equal to or more than Grade III and 2 of them underwent mitral valve regurgitation equal to or more than Grade III and 2 of them underwent mitral valve replacement 6 months and 12 years after the initial operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Tetralogy of Fallot with anomalous origin of left pulmonary artery.

Between 1971 and 1990, 7 patients of tetralogy of Fallot with anomalous origin of left pulmonary artery underwent intracardiac repairs at Tohoku University Hospital. They were 2 males and 5 females with ages ranging from 4 to 26 years old. The right pulmonary artery connected to right ventricle in all cases, whereas no communications between right ventricle and the left pulmonary artery were found. The left pulmonary artery directly originated from the ascending aorta in 2 patients (group I) and connected to the ductus arteriosus in 5 patients (group II and III). In 2 patients (group II), the left pulmonary artery was separated from the pulmonary arterial trunk by the intraluminal membrane, receiving blood supply through the ductus. In the remaining 3 patients (group III), there were no continuations between both pulmonary arteries. At the correction, communication between the left pulmonary artery and the pulmonary arterial trunk could be reconstructed in groups I and II. However, it was not possible in group III, because the ductus arteriosus and the left pulmonary artery had already been occluded before the intracardiac repair. In group III, ventricular septal defect was closed using a one-way valved patch or a perforated patch to decrease supersystemic right ventricular pressure. Postoperative right ventricular aortic pressure ratio was between 0.5 and 0.8 in groups I and II, and between 0.8 and 1.0 in group III. Three patients (one in each group) died after the operation. Severe pulmonary vascular obstructive disease was found in the left lung of group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Hb Kanagawa [alpha 40(C5)Lys----Met]: a new alpha chain variant with an increased oxygen affinity.

An abnormal hemoglobin was suspected in a 70-year-old Japanese male with cerebral infarction and erythremia with high performance liquid chromatography assay of Hb A1c. The hemoglobin variant migrated to the anode more rapidly than Hb A. Structure determination studies, including amino acid analysis of the abnormal peptide and DNA sequencing of a partially cloned alpha-globin gene, demonstrated that it is a new hemoglobin variant which has been named Hb Kanagawa [alpha 40(C5)Lys----Met]. This variant showed an increased oxygen affinity, decreased heme-heme interaction, and a lowered 2,3-diphosphoglycerate effect relative to normal.

Aged↗