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Biomedical subjects

H Hashimoto

Publications and source records attributed to H Hashimoto.

1,583 records · Page 88Linked to original sources
PubMedDate not supplied

The newly designed univalved artificial heart.

A univalved artificial heart (AH) powered electromagnetically in the frequency range of 1-30 Hz was developed to obtain a totally implantable AH. This small sized AH consisted of a vibrating tube, coils, magnets, and a jellyfish valve as an outlet AH valve. The fluid mechanical, hemodynamic, and hematologic properties were evaluated in a mock circulation and 10 animal experiments using adult goats. This vibrating electromagnetic AH could generate more than 10 L/min as an output volume, with 10 Hz vibration using 20 volts supplied voltage. It could also provide two kinds of flow and pressure patterns, in constant-peak and periodic-peak patterns. The values of free hemoglobin remained within acceptable limits. The authors concluded that this new type of pump was useful as a totally implantable AH, ventricular assist, or organ assist system.

Blood Flow Velocity↗
PubMedDate not supplied

Comparison of the cardiac electrophysiologic effects of amitriptyline and clomipramine in the dog after myocardial infarction.

The effects of the tricyclic antidepressants amitriptyline and clomipramine on intraventricular conduction, effective refractory period and incidence of ventricular arrhythmias induced by programmed stimulation, were studied in the dog heart after myocardial infarction. Amitriptyline, at doses of 1 to 3 mg/kg, significantly slowed ventricular conduction of the infarcted zones in a frequency-dependent and a dose-dependent manner. Amitriptyline, at doses of 2 and 3 mg/kg, slightly slowed conduction in normal zones. The effective refractory period was prolonged by amitriptyline at a dose of 2 mg/kg. Amitriptyline increased the incidence of ventricular arrhythmias induced by programmed stimulation. On the other hand, the depressant effect of clomipramine, at doses of 1 to 3 mg/kg, on the conduction of infarcted zones was lower than that of amitriptyline, whereas the severely depressed conduction in the infarcted zone was obviously slowed by clomipramine. The incidence of ventricular arrhythmias did not significantly increase with clomipramine. From the present results, clomipramine seems to have a lower cardiac toxicity than amitriptyline, although clomipramine produces a slight depression of conduction in infarcted zones.

Amitriptyline↗
PubMedDate not supplied

Functional and metabolic effects of bucladesine (dibutyryl cyclic AMP) in the working rat heart preparation: comparison with dopamine.

The effects of bucladesine (10(-4) and 3 x 10(-4) M) on cardiac function and energy metabolism were investigated in comparison with those of dopamine (3 x 10(-6) and 10(-5) M) in the working rat heart preparation. Bucladesine dose-dependently increased systolic pressure, cardiac work and coronary flow, but scarcely changed heart rate or cardiac output at 78 cm H2O perfusion pressure. Dopamine increased systolic pressure to a similar extent as bucladesine and also increased heart rate, cardiac work and coronary flow, but did not change cardiac output. Neither drug caused any changes in energy metabolites. At reduced perfusion pressure (15 cm H2O), bucladesine increased systolic pressure, coronary flow and cardiac output, but caused a decrease (at 10(-4) M) or a negligible change (at 3 x 10(-4) M) in heart rate. At 10(-4) M, there was only a slight change in energy metabolism, but at 3 x 10(-4) M, anaerobic metabolism was enhanced. Dopamine decreased systolic pressure and coronary flow and increased heart rate and cardiac work. Cardiac output increased transiently and, thereafter, decreased. Dopamine also enhanced anaerobic metabolism at both doses. The results suggest that both drugs exert similar effects at normal perfusion pressure, but after reduction of perfusion pressure, some differences occur between the two drugs, presumably due to acceleration of the heart rate and subsequent increase in cardiac work by dopamine.

Adenosine Triphosphate↗
PubMedDate not supplied

Altered responsiveness of coronary arteries in hyperthyroid rats.

The effect of thyroid hormones on vascular responses to various agents was examined in the coronary vascular bed perfused by the Langendorff's method at a fixed flow rate with Krebs-Henseleit solution in isolated rat hearts. In this study, ventricular fibrillation was induced by electrical stimulation to avoid secondary influences derived from alteration of ventricular contractility by agents. Vasodilator responses of coronary arteries to isoproterenol and methacholine were significantly enhanced in hyperthyroid preparations compared with those observed in euthyroid ones, though vasodilator responses to histamine and adenosine were not affected by hyperthyroidism. Vasoconstrictor response to 5-hydroxytryptamine (5-HT) was significantly potentiated by hyperthyroidism though that to balium chloride was not affected. So, these alterations in vascular responses by hyperthyroidism are assumed not to be nonspecific but to be mediator-specific events. As vasoconstriction in coronary arteries lowers oxygen supply to myocardium, enhanced vasoconstrictivity of coronary arteries to 5-HT by hyperthyroidism may be responsible for an exacerbation of heart disease in the case of patients having agglutinative thrombus, which should be a source of 5-HT, in their coronary arteries.

Adenosine↗
PubMedDate not supplied

Comparative effects of the antidepressants amitriptyline, mianserin and adinazolam on hemodynamics and ECG in myocardial infarcted dogs.

This study was undertaken to examine the effects of mianserin (MIA), a tetracyclic antidepressant, and adinazolam (ADI), a new benzodiazepine antidepressant on cardiac function and electrocardiogram in normal and infarcted hearts of anesthetized dogs, and to compare the effects with those of amitriptyline, a commonly used tricyclic antidepressant. The parameters measured were: heart rate (HR); mean arterial blood pressure (MP); aortic flow (AF); maximal rate of increase of left ventricular pressure (LV dp/dt); blood flow of left circumflex of left coronary artery (CAF) and PQ and QRS intervals. The double product (DP) was calculated from HR and the arterial pressure. AMI increased HR, DP, LV dp/dt and CAF in the normal group, while in the infarcted group, AMI increased HR, DP and CAF, but decreased LV dp/dt at 3 mg/kg. AMI at 2 and 3 mg/kg prolonged QRS intervals in the infarcted groups. MIA increased HR and DP in the normal group at doses of 1 mg/kg or more, while in the infarcted group it produced only slight effects in hemodynamic parameters and PQ and QRS intervals. ADI had little effect on hemodynamics and PQ and QRS intervals in the normal group. However, it decreased LV dp/dt, CAF, MP at 3 mg/kg in the infarcted group. In conclusion, AMI markedly influenced cardiac hemodynamics and QRS interval in the myocardial infarcted group, while, on the other hand, MIA and ADI, in clinical doses, had only a slight effect on hemodynamics and PQ and QRS intervals in the infarcted group. Thus MIA and ADI were safer than AMI in the animals with myocardial infarction.

Amitriptyline↗
PubMedDate not supplied

Changing patterns in the clinical features and prognosis of systemic lupus erythematosus - a Japanese experience.

The changing patterns of clinical features and prognosis of 307 Japanese patients with systemic lupus erythematosus (SLE) were studied. SLE patients with Raynaud's phenomenon, alopecia and oral ulceration increased significantly in Group B (1970-1979) compared to Group A (1955-1969). It was noted that SLE patients with LE cells were significantly fewer in Group B and in Group A. The prognosis of Group B was significantly improved over that of Group A. There was a significant decline in deaths caused by uremia and central nervous system lupus in Group B.

Female↗
PubMedDate not supplied

Role of eicosapentaenoic acid in lipid metabolism in the liver, with special reference to experimental fatty liver.

Choline-deficient feed was given to three groups (n = 7 in each) of male Sprague-Dawley rats for 4 weeks to induce the development of fatty liver. In addition, two of the groups received eicosapentaenoic acid (EPA), 1000 mg/kg/d, administered orally either for all 4 weeks or for only the last 2 weeks of the study, respectively. The third group received the choline-deficient diet but no EPA. The untreated control group (n = 7) received only normal feed. The efficacy of EPA in preventing fatty liver was assessed based on the evaluation of pathologic and biochemical parameters and hepatic blood flow. EPA markedly improved fatty liver, probably due to both direct effects (inhibition of the synthesis of triglyceride in the liver) and indirect effects (increased hepatic blood flow). Decreased blood flow due to sinusoidal block is responsible for the progression of fatty liver. EPA has been shown to decrease thromboxane A2 production and blood viscosity and to enhance red cell deformability. These effects are thought to have contributed to the increases in hepatic blood flow.

Animals↗
PubMedDate not supplied

Effects of imipramine and amitriptyline on intraventricular conduction, effective refractory period, incidence of ventricular arrhythmias induced by programmed stimulation, and on electrocardiogram after myocardial infarction in dog.

The effects of imipramine and amitriptyline on intraventricular conduction, effective refractory period, incidence of ventricular arrhythmias induced by programmed stimulation and on electrocardiogram changes were studied after myocardial infarction in the dog. Amitriptyline, at doses of 1-3 mg/kg, significantly slowed the ventricular conduction of the infarcted zones in a dose- and frequency-dependent manner. Amitriptyline, at doses of 2 and 3 mg/kg, slowed the ventricular conduction slightly in the normal zone. The effective refractory period was prolonged by amitriptyline at a dose of 1 mg/kg. Amitriptyline increased the incidence of ventricular arrhythmias induced by programmed stimulation. Amitriptyline, at doses of 1-3 mg/kg, increased heart rate and prolonged the PQ, QRS and QT interval. Imipramine, at a dose of 3 mg/kg, slowed the conduction in infarcted zones to a lesser extent than amitriptyline. Imipramine, at doses of 1 and 2 mg/kg, did not significantly increase the incidence of ventricular arrhythmias. Imipramine, at a dose of 3 mg/kg, prolonged the QRS interval. From the present results it appears that imipramine has a lower cardiac toxicity than amitriptyline.

Amitriptyline↗
PubMedDate not supplied

CT evaluation of primary benign retroperitoneal tumor.

We studied CT patterns in 21 cases of primary benign retroperitoneal tumor including teratoma in nine cases, schwannoma in six, leiomyoma in three, lipoma in one, lymphangioma in one, and neurofibroma in one. The tumors were analyzed for size, internal homogeneity, CT density, calcification, border with neighboring organs, and contrast enhancement (CE). The mean diameter of the tumors was 10.2 (+/- 4.8) cm. Internal homogeneous distribution was observed in 33%, calcification in 43%, and well-defined border in 86%. The CT density and calcification were compared according to histology, and the results were as follows: teratoma showed fat density in 78%, water density in 100%, and calcification in 89%; schwannoma showed water density in 100% and septal CE in 33%; leiomyoma showed soft tissue density in 100%, CE in 100%, and water density in 33%; lipoma showed fat density and calcification; and lymphangioma and neurofibroma showed water density. Internal homogeneity, fat density, cyst formation, and calcification are considered to be important predictors of primary benign retroperitoneal tumor on CT.

Adolescent↗
PubMedDate not supplied

Inhibitory effect of ursodeoxycholic acid on the progression of chronic hepatic disorders with special reference to increases in blood flow.

Ursodeoxycholic acid (UDCA), which is commonly used as a cholesterol-gallstone-dissolving agent, is now expected to be effective not only for primary biliary cirrhosis but for chronic active hepatitis as well. In this study, we administered 0.1% ethionine-added, choline-deficient diet for 8 weeks to male Sprague-Dawley rats to prepare an animal model of chronic hepatic disorders. At the same time, UDCA (50 mg/kg/day) was administered orally to these animals, and its effects on the liver, including effects on hepatic blood flow determined with a laser Doppler blood flow meter, were evaluated. Hepatic blood flow increased significantly in the UDCA group compared with the untreated groups. Transaminase levels decreased significantly in the UDCA group compared with the untreated group. Histologic differences were noted between the UDCA and untreated groups in histopathologic examinations of the liver, with liver cirrhosis or early liver cirrhosis being present in the untreated group, compared with only chronic active hepatitis in the UDCA group. These findings suggest that UDCA is able to prevent or inhibit the progression of chronic hepatic disorders, an effect that may be due in part to increases in hepatic blood flow.

Alanine Transaminase↗
PubMedDate not supplied

Evaluation of renal and perirenal leiomyoma on US, CT, and angiography.

The findings of US, CT, and angiography were analyzed in five rare cases of renal and perirenal leiomyoma. The margin of the tumors was shown to be regular by each method, and the tumors were found to be heterogeneous by US and CT. US showed hypoechoic (80%) and mixed echoic (20%) echo patterns. CT revealed soft tissue density with contrast enhancement. Angiography disclosed hypovascularity (25%), and slight vascularity (75%), but no arterial encasement, A-V shunt, or vein invasion. Although no findings specific to the differential diagnosis of malignant tumors were found, benign tumors should be considered when the following signs are detected: (1) a large (more than about 5 cm), well-defined, regular abdominal mass with few symptoms, (2) a heterogenous hypoecho on US, (3) enhanced soft tissue density on CT, and (4) angiography without arterial encasement, A-V shunt, or vein invasion.

Diagnostic Imaging↗
PubMedDate not supplied

Aflatoxin contamination in foods and foodstuffs in Tokyo: 1986-1990.

Aflatoxins were determined in 3054 samples of foods or foodstuffs, including cereals, nuts, beans, spices, dairy products, dry fruits, and edible oil. Samples were collected in Tokyo from 1986 to 1990. Aflatoxins were found in rice products, adlay, corn, crude sugar, peanut products, pistachio nuts, brazil nuts, sesame products, butter beans, white pepper, red pepper, paprika, nutmeg, and mixed spices. The highest incidence of aflatoxin contamination was observed in nutmeg (80%), and the highest level of aflatoxin B1 was observed in pistachio nuts (1382 ppb).

Aflatoxins↗
PubMedDate not supplied

Increased serum CA19-9 in patients with xanthogranulomatous cholecystitis.

We present three cases of xanthogranulomatous cholecystitis (XGC) with an increased serum carbohydrate antigen 19-9 (CA19-9). All of the patients were elderly females and had gallstones lodged in the neck of the gallbladder. Preoperative serum CA19-9 levels were 709 U/ml, 87 U/ml, and 400 U/ml, respectively. A cholecystectomy with or without bile duct exploration was performed, and the histological diagnosis of XGC was made. Serum CA19-9 levels fell to normal levels in two patients who recovered uneventfully, but rose again in one patient who died of cholangitis. Clinicians must remember that XGC is a possible cause of increased serum CA19-9 levels.

Aged↗
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HIV infection and SLE: their pathogenic relationship.

Retroviruses have repeatedly been suggested as a possible trigger mechanism for systemic lupus erythematosus (SLE). We review the role of human immunodeficiency virus (HIV)-1 envelope glycoprotein (gp120) in the induction of immune dysregulation including autoimmunity in HIV-1 infection, and discuss the possible relationship between HIV and SLE in the retroviral etiology.

Acquired Immunodeficiency Syndrome↗
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HLA-DRB1 alleles and beta 2 glycoprotein I-dependent anticardiolipin antibodies in Japanese patients with systemic lupus erythematosus.

OBJECTIVE: To investigate the association of HLA DRB1 alleles with beta 2 glycoprotein I (beta 2 GPI)-dependent anticardiolipin antibodies (aCL) in Japanese patients with systemic lupus erythematosus (SLE). METHODS: One hundred and forty-five Japanese patients with SLE were studied. beta 2 GPI-dependent aCL was measured by enzyme-linked immunosorbent assays. DNA typing of the DRB1 alleles was performed by the polymerase chain reaction sequence specific oligonucleotide probe method. RESULTS: beta 2 GPI-dependent aCL was positive in 29 (20.0%) out of 145 SLE patients. SLE patients with beta 2 GPI-dependent aCL had a significantly higher frequency or one or more of the clinical manifestations assumed to be associated with aCL, compared to those without beta 2 GPI-dependent aCL (p < 0.05). The frequency of DRB1*0901 was lower in SLE patients than in healthy subjects. SLE patients with beta 2 GPI-dependent aCL were significantly associated with DRB1*0901 as compared to those without beta 2 GPI-dependent aCL (41.4% vs 15.5%, p < 0.005, R.R. = 3.8), although the corrected P value was not significant. CONCLUSION: A possible association of DRB1*0901 with Japanese SLE patients with beta 2 GPI-dependent aCL was found. This association indicates an association between the disease and the HLA-DR53 (DRB4)-bearing haplotypes in different ethnic groups.

Alleles↗
PubMedDate not supplied

Three-dimensional power Doppler sonography of tumor vascularity.

PURPOSE: To assess the clinical value of three-dimensional (3D) power Doppler imaging of intratumoral blood flow. MATERIALS AND METHODS: Two hepatocellular carcinomas (HCC), one renal cell carcinoma, one hepatic focal nodular hyperplasia (FNH), and one iliac bone metastasis of HCC were used. Images were collected by power mode using the GE-Yokogawa LOGIQ 700. Power Doppler images were recorded on S-VHS videotape and fed into a workstation. Flow information was then extracted, and 3D images were constructed by surface rendering. RESULTS: Preparation of 3D images could be accomplished in one minute after feeding flow information into the workstation. Intratumoral vascular structure could be easily evaluated. This 3D imaging was useful for the differential diagnosis of hepatic tumors, especially HCC and FNH, which were confirmed in 3D imaging to have distinctly different intratumoral vascular structures. CONCLUSION: 3D imaging of intratumoral blood flow was possible by 3D processing of the power Doppler images. 3D power Doppler imaging is expected to be helpful for the differential diagnosis of tumors.

Bone Neoplasms↗