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Biomedical subjects

T Misaki

Publications and source records attributed to T Misaki.

At least 217 records · Page 12Linked to original sources
PubMed1989

[Comparative analysis of mechanical and biological prosthetic valves after isolated valve replacement--cooperative study on total 1281 patients].

A total of 1281 patients (594 aortic and 687 mitral) received 734 mechanical valves (320 Björk-Shiley, 283 SJM and 131 Omniscience) and 547 biological (259 ionescu-Shiley, 227 Hancock, and 61 Carpentier-Edwards) were analyzed for postoperative valve dysfunction and thromboembolism. The actuarial survival rates (free from late cardiac deaths and valve-related deaths) were 88.6% (11 years) for mechanical mitral and 86.0% (11 years) for biological mitral valves, and 91.7% (16 years) and 88.5% (12 years), for mechanical and biological aortic valves, respectively. There were no significant differences among these groups. Actuarial rates of freedom from valve-related events were 88.7% (11 years) and 51.7%, for mechanical and biological mitral valves, respectively. There was significant difference between the two types of valves in over 7 years after surgery. In contrast, there were no significant differences between mechanical and biological aortic valves. Actuarial rates of freedom from valve dysfunction were 97.6% (11 years) for mechanical and 56.5% (12 years) for biological mitral valves. The net 12 year results showed no significant differences between the two types of mitral prosthetic valves, but a significantly increased rate of valve dysfunction in the biological mitral valves compared with the mechanical in over 6 years of the study. Concerning AVR, there were no significant differences in the incidence of valve dysfunction between mechanical and biological aortic valves. Actuarial rates of freedom thromboembolism were 92.3% (11 years) and 93.8% (11 years) for mechanical and biological mitral valves, respectively. There were no significant differences between the two types of mitral prosthetic valves.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1989

[Left ventricular performance before and after left ventriculotomy and removal of a left ventricular aneurysm].

The effects of left ventriculotomy on left ventricular performance were studied in seven patients with ventricular tachyarrhythmia (VT) and nine patients with left ventricular aneurysm (LVA). Hemodynamic and left ventriculographic findings were evaluated before and after operations. In VT the non-contracting areas, measured at end-diastole, as mean 10.8 +/- 7.1% of the left ventricular internal surface area. There was no significant fall in left ventricular ejection fractions (EF), cardiac indexes (CI) and left ventricular end-diastolic volume indexes (LVEDVI) after left ventriculotomy. In LVA, the non-contracting areas decreased from 31.0 +/- 7.4% to 13.7 +/- 13.5% (p less than 0.01) in association with a reflex decrease in LVEDVI from 117 +/- 31.8 ml/m2 to 90.4 +/- 24.7 ml/m2 (p less than 0.05). EF increased from 40.8 +/- 7.00% to 54.6 +/- 10.7% (p less than 0.01). There was no significant change in CI and left ventricular stroke volume index after left ventricular aneurysmectomy. The observations indicate that left ventriculotomy of limited size is an acceptable and a safety approach to the ventricular tachyarrhythmias and another cardiac operations.

Adolescent↗
PubMed1989

[A case of lupus cystitis].

A case of lupus cystitis in a 23-year-old male is reported. The patient began to complain of diarrhea and vomiting in October, 1985. When the diagnosis of systemic lupus erythematosus (SLE) was established at the Department of Internal Medicine in our hospital, he was referred to our clinic for examination of pollakisuria on November 22. DIP revealed a loss of bladder distensibility, and bilateral hydronephrosis and hydroureter. Transurethral cold cup biopsies revealed subcutaneous edema. A diagnosis of lupus cystitis was made and he was treated with steroids, which resulted in symptomatic and radiographic improvement.

Adult↗
PubMed1989

[Surgical management of infective endocarditis].

We reviewed fourty-six patients who had undergone surgery for infective endocarditis in the past fifteen years and identified risk factors affecting the outcome. Twenty-nine patients had infection of the native valve only, 11 had infective endocarditis associated with congenital heart disease, and 6 had prosthetic valve endocarditis. Overall hospital mortality was 6.5%. Prosthetic valve endocarditis carried a higher mortality (33%) than native valve endocarditis (3.4% or congenital heart disease with infective endocarditis (0%). For the patients with active endocarditis, the early mortality rate was higher (13%) than with inactive endocarditis (3.2%). Staphylococcal infections were more likely to cause severe valve destruction and residual infection than streptococcal infection. Our results indicated that surgical management of infective endocarditis should be done after the completion of adequate antibiotic therapy. Early diagnosis should reduce the mortality, prevent fatal complications, and lead to qualitative improvement of infective endocarditis.

Adolescent↗
PubMed1989

[Surgical treatment of ventricular tachycardia caused by abnormal muscle band].

A 57-year-old male was introduced to our hospital for his drug resistant non-ischemic ventricular tachycardia causing faintness attack. Preoperative electrophysiological studies led to a diagnosis of ventricular tachycardia originating from the right ventricular outflow tract. After ventriculotomy, an abnormal muscle band was noticed in the right ventricular outflow tract, which seemed to be a focus of tachycardia by endocardial mapping. Myocardial excision with the abnormal muscle band was performed. In addition to, cryoablation was performed surrounding this area. After the operation, the ventricular tachycardia disappeared completely. No antiarrhythmic drug have been required at 18 months postoperative months.

Cryosurgery↗
PubMed1989

[Skeletal muscle ventricle used for right ventricle assistance].

There are a number of advantages in using an electrically stimulated autogenous skeletal muscle to construct an auxiliary ventricle to assist a heart. The purpose of this study was to determine the feasibility of biological right ventricular assistance using long-term electrically stimulated skeletal muscle grafts. In fourteen dogs, the latissimus dorsi muscles and the right thoracodorsal nerves were exposed and unipolar pulse generator was implanted. The initial rate of 70 cycle/min. was increased to a rate of 100 cycle/min. Six or 12 months later, the latissimus dorsi was wrapped around a latex pouch equipped with inflow and outflow valved conduit (skeletal muscle ventricles; SMVs). The SMVs were connected to main pulmonary artery and right atrium. These SMVs were stimulated 20 Hz for 200 msec at a fixed rate of 90 cycle/min, the hemodynamic changes with or without skeletal muscle ventricular assistance (SMVA) were measured. In as animals the circulation failed after total right ventricular bypass without SMVA. But the SMVA increased aortic blood pressure, aortic blood flow, left atrial pressure and peak pulmonary pressure significantly. There was a linear correlation between central venous pressure and skeletal muscle ventricular assist flow. Histologic studies showed the conditioned muscles had a greater percentage of slow-twitch, fatigue resistant fibers on ATPase stain. These results suggested the long-term electrical conditioning skeletal muscle could be possible to use SMVs in humans to provide support in children with some types of congenital heart disease.

Animals↗
PubMed1989

[Percutaneous removal of renal and ureteral calculi in 104 patients].

One hundred and four consecutive patients with renal and/or ureteral calculi, 66 males and 38 females with an average age of 44.3 years ranging from 17 to 83, were treated by a percutaneous procedure between September, 1984 and October, 1987. In an early series of 6 patients, a two-stage procedure consisting of temporary renal drainage and the introduction of an endoscope a few days later was employed. The remaining 98 patients received a so-called one-stage procedure. The stone was removed successfully in 96 patients with an average operation time of 140 minutes. In 2 of the 96 patients, renal stones recurred 7 months and 20 months later. The most common cause for failure in stone removal was the difficulty of engaging calyceal stones and ureteral stones using a basket and/or 3-prong grasper, because of inflammatory mucosa adhering to the stones. Out of 8 failures, 7 and 1 required an open operation and trans-urethral intervention, respectively. There were 40 complications in 33 patients. Of 11 patients in whom renal pelvic perforation occurred, 2 required open surgical repair. Of 5 patients complaining of renal bleeding, 1 required renal artery embolization. With increasing experience and improving procedure, most renal, and upper and mid ureteral stones have been safely and successfully removed percutaneously.

Adolescent↗
PubMed1989

[Successful surgical treatment of atrial tachyarrhythmias].

Three cases with ectopic atrial tachycardia and two cases with atrial flutter (AF), unresponsive to drugs, are described clinically and electrophysiologically. The three patients of ectopic atrial tachycardia were treated by surgical removal of ectopic focus and cryocoagulation of the adjacent area, not using cardiopulmonary bypass. All of them have been in sinus rhythm and had shown no tachycardia since the operation. In one patient of AF, cryosurgical ablation around the atrioventricular (AV) node and His bundle has prevented AF without AV block. Another patient of AF underwent cryoablation around the orifice of the coronary sinus, which was the earliest activation area during AF in endocardial mapping. In this patient, AF reappeared, so cryoablation around the AV node and His bundle was performed. His heart rate decreased to 120 beat/min from 270 beats/min during AF and a radiofrequency pacemaker (Atricon) was implanted to interrupt the remaining AF. This cryosurgical procedure is successful to modify and preserve AV conduction.

Adolescent↗
PubMed1988

Serial immunologic identification of lymphocyte subsets in murine coxsackievirus B3 myocarditis: different kinetics and significance of lymphocyte subsets in the heart and in peripheral blood.

To elucidate possible immune mechanisms in the pathogenesis of myocarditis, we examined, by immunofluorescence techniques, the serial changes in lymphocyte subsets in the heart, spleen, and peripheral blood of C3H/He mice inoculated coxsackievirus B3 (experiment I). B cells were identified by staining with fluorescein isothiocyanate-labeled rabbit antimouse immunoglobulin. T cell subsets were demonstrated with rat anti-Thy 1.2, anti-Lyt 1, anti-Lyt 2, and anti-L3T4 monoclonal antibodies, respectively, plus fluorescein isothiocyanate-labeled antimouse immunoglobin. The percent of Thy 1.2+, Lyt 1+, and L3T4+ cells was decreased in the peripheral blood on days 3, 7, and 14. B cells were increased on day 3. In contrast, Thy 1.2+ (pan T) or Lyt 1+ cells appeared to occupy the major portion of the myocardium on days 7 and 14, when myocarditis was most severe, while B cells were sparse. For confirmation, serial immunohistologic studies (immunoperoxidase staining) of the hearts of C3H/He mice with coxsackievirus B3 myocarditis were performed (experiment II). Most of the stained cells in the heart were Thy 1.2, Lyt 1, and Lyt 2 positive on days 7 and 14. Thus, independent methods demonstrate that specific antigenic markers on lymphocytes at the site of inflammation in the acute stage of viral myocarditis differ from those on corresponding peripheral lymphocytes, and suggest the possible involvement of Thy 1.2+ (pan T) cells, mainly the Lyt 1+ and Lyt 2+ subsets (immature T cells), in the development of myocarditis in this preparation.

Animals↗
PubMed1988

Effects of rat gamma- and non-gamma-interferons on the expression of Ia antigen, growth, and differentiated functions of FRTL5 cells.

We undertook the present studies with several objectives in mind: 1) to determine whether recombinant rat gamma-interferon (r gamma IFN) would induce expression of the class II major histocompatibility antigen (Ia) in rat thyroid follicular cells (FRTL5) in culture as human gamma IFN does in cultured human thyrocytes; 2) to characterize the properties of this response, if it does indeed occur; 3) to ascertain whether r gamma IFN has any effect on the growth or differentiated function of FRTL5 cells; and 4) to determine how, if at all, effects of r gamma IFN on the growth and function of FRTL5 cells might be related to expression of the Ia antigen. At concentrations between 1 and 30 U/ml, r gamma IFN induced expression of Ia antigen in a concentration-dependent manner. With a supramaximal concentration of r gamma IFN, Ia antigen first appeared between 4 and 16 h and reached a maximum concentration at about 36 h. After removal of r gamma IFN, the Ia antigen concentration remained constant for about 24 h and then declined, becoming undetectable by 72 h. Induction could not be detected in FRTL5 cells cultured with human gamma IFN, rat non-gamma IFN, Concanavalin-A, phytohemagglutinin, or bovine TSH (bTSH). Over the same range of concentrations that induced the Ia antigen, r gamma IFN proved to be a potent inhibitor of the growth of FRTL5 cells induced by a variety of agents. It produced a concentration-dependent inhibition of the stimulation of [3H] thymidine incorporation and cell replication in FRTL5 cells induced by bTSH. This effect was unaccompanied by any inhibition of either the binding of bTSH to FRTL5 cells or the bTSH-induced increase in cellular cAMP concentration induced therein. However, r gamma IFN did inhibit the stimulation of [3H] thymidine incorporation into DNA induced by (Bu)2cAMP. r gamma IFN also inhibited the stimulation of DNA synthesis and cell replication induced by insulin-like growth factor I (IGF-I) without affecting the specific binding of IGF-I, and decreased the extent of stimulation of [3H]thymidine incorporation induced by the phorbol ester tetradecanoyl phorbol acetate (TPA). Thus, r gamma IFN inhibited both the cAMP-dependent pathway of growth activated by TSH, doing so at some post-cAMP locus, and the cAMP-independent pathways of growth regulation that are activated by IGF-I and TPA.(ABSTRACT TRUNCATED AT 400 WORDS)

Aminoisobutyric Acids↗
PubMed1988

Supranormal stimulation of deoxyribonucleic acid synthesis in FRTL5 cells by serum from patients with untreated acromegaly.

Insulin-like growth factor I (IGF-I) is one of a number of mitogenic factors in the serum of animals and humans. We demonstrated previously that IGF-I is a potent mitogen for FRTL5 cells, a line of rat thyroid follicular cells. In this study, we assessed the relevance of this finding with respect to the levels of IGF-I found in human serum by comparing the effects of normal serum and serum from patients with untreated acromegaly or hypopituitarism on DNA synthesis in quiescent FRTL5 cells. As expected, when added to cells maintained in Coon's modified Ham's F-12 medium containing 0.1% BSA, but devoid of insulin, transferrin, TSH, or calf serum, normal serum produced a dose-dependent stimulation of [3H]thymidine incorporation into DNA. A similar, but more marked, effect was produced by the addition of serum from patients with untreated acromegaly. In multiple experiments, a standard concentration (0.5%) of acromegaly serum was more stimulatory to DNA synthesis than was normal serum. In a single experiment designed to eliminate interassay variation and define the relationship between the ability of serum to stimulate DNA synthesis and its IGF-I concentration, studies were performed with 0.5% concentrations of serum from 9 normal subjects, 15 patients with untreated acromegaly, and 3 patients with panhypopituitarism. On the average, [3H]thymidine incorporation in the presence of serum from patients with acromegaly was approximately 3 times, and that in the presence of serum from patients with hypopituitarism only one fourth, that in the presence of serum from normal subjects; there was no overlap of individual values in the three groups. For the entire study group, we found a highly significant correlation (r = 0.86) between the serum IGF-I concentration and the ability of that serum to stimulate thymidine incorporation into the DNA of FRTL5 cells. The stimulatory effects of serum from both normal and acromegalic subjects were decreased or abolished by the addition of a monoclonal antibody against IGF-I. In hypophysectomized rats, GH increases the thyroid to body weight ratio and enhances the effect of TSH to promote thyroid growth. Further, an inordinate frequency of nontoxic goiter in patients with acromegaly has been reported. Taken together with these observations, our findings suggest that the effect of IGF-I to promote thyroid cell growth in vitro has a counterpart in the living animal or patient.

Acromegaly↗
PubMed1988

Inhibition of thyrotropin-stimulated iodide uptake in FRTL-5 thyroid cells by crude immunoglobulin fractions from patients with goitrous and atrophic autoimmune thyroiditis.

We studied the effects of crude immunoglobulin (Ig) fractions of serum from patients with goitrous and atrophic autoimmune thyroiditis on TSH-, thyroid-stimulating immunoglobulin (TSI)-, forskolin-, and dibutyryl cAMP-stimulated 125I uptake by FRTL-5 thyroid cells. TSH-stimulated 125I uptake was inhibited by the Ig fractions from 15 patients with atrophic thyroiditis who had serum TSH binding inhibitor Igs (TBII), 10 (62.5%) of 16 TBII-negative patients with atrophic thyroiditis, 7 (43.8%) of 16 hypothyroid patients with goitrous thyroiditis who had no TBII activity, and only 2 (15.4%) of 13 euthyroid patients with goitrous thyroiditis who were negative for TBII. The mean inhibition of TSH-stimulated 125I uptake produced by the crude Igs from the former 3 groups of hypothyroid patients was statistically significant (P less than 0.001, P less than 0.001, and P less than 0.01, respectively) and correlated closely with the ability of the Ig fractions to inhibit TSI-stimulated 125I uptake (r = 0.882) and TSH-stimulated cAMP accumulation (r = 0.929). The inhibition of TSH- or TSI-stimulated 125I uptake by Ig samples containing TBII correlated significantly with the TBII activities. On the other hand, in the presence of Igs from TBII-negative hypothyroid patients, the inhibition of TSH-stimulated 125I uptake correlated significantly with that of forskolin-stimulated 125I uptake (r = 0.685). Although 6 (12.8%) of 47 Ig samples from hypothyroid patients inhibited dibutyryl cAMP-stimulated 125I uptake, the activities were marginal. These findings suggest that at least 2 types of antibodies are involved in the inhibition of TSH- or TSI-stimulated 125I uptake: 1 being a competitive inhibitor of TSH binding to its receptors, and another exerting influence on a step subsequent to TSH or TSI binding, presumably through adenylate cyclase inhibition.

Bucladesine↗
PubMed1988

Antibody-dependent cell-mediated growth inhibition of rat thyroid cells, FRTL-5, in patients with autoimmune thyroid diseases.

We studied antibody-dependent mononuclear cell-mediated growth inhibition of thyroid cells in 18 untreated patients with Graves' disease, 18 patients with chronic thyroiditis, and 15 normal subjects by measuring the ability of their sera to inhibit [3H]thymidine incorporation into DNA in a rat thyroid cell line, FRTL-5, in the presence of normal mononuclear cells. [3H]thymidine incorporation was significantly inhibited in the presence of sera from patients with Graves' disease and chronic thyroiditis (P less than 0.001), whereas it was not affected in normal subjects. A significant correlation was observed between the inhibition of [3H]thymidine incorporation and the titre of anti-microsomal antibodies (P less than 0.05). The inhibitory effect on [3H]thymidine incorporation was significantly abolished when serum pre-absorbed with human thyroid membranes was used (P less than 0.005). These inhibitory effects on [3H]thymidine incorporation significantly correlated with those obtained by using IgG fractions (P less than 0.01). These data indicate that antibody-dependent mononuclear cell-mediated growth inhibition may play a role in thyroid cell growth regulation in patients with autoimmune thyroid disease.

Adolescent↗
PubMed1988

Sensitive, practical bioassay of thyrotropin, with use of FRTL-5 thyroid cells and magnetizable solid-phase-bound antibodies.

We have developed a new method for assessing the bioactivity of thyrotropin (TSH) in human serum by measuring cAMP production in FRTL-5 thyroid cells as an index of stimulation. To eliminate serum inhibitors of the cAMP response to TSH, we purified samples by mixing them with anti-TSH antibodies coupled to magnetizable particles. This method of immunoaffinity purification was simple and suitable for the measurement of a large number of samples. The detection limit of the bioassay was 3.13 milli-int. units of human TSH per liter. Intra-assay and interassay coefficients of variation ranged from 5.4 to 8.6% and from 12.6 to 21.5%, respectively. The concentrations of bioassayable TSH closely correlated with those of immunoassayable TSH, both in the immunoaffinity-purified samples (r = 0.946, P less than 0.001) and in the serum samples (r = 0.945, P less than 0.001) from 14 euthyroid subjects and 53 hypothyroid patients with Hashimoto's thyroiditis. The bioactivity-to-immunoactivity ratio was almost constant (0.84 +/- 0.30; mean +/- SD) over the range of concentrations of immunoassayable TSH in serum, 6.3 to 177 milli-int. units/L. We also demonstrate that the technique is applicable to measurements of bioactivities of circulating forms of immunoreactive TSH in different pathophysiological conditions.

Animals↗
PubMed1988

[A case of von Hippel-Lindau disease associated with bilateral renal cell carcinoma].

A case of von Hippel-Lindau disease associated with bilateral renal cell carcinoma is presented. A 27-year-old female noticed myodesopsia and underwent laser coagulation of right retinal hemangioma in 1973. In addition, cerebellar hemangioblastomas were removed in 1977, 1978, 1983 and 1987. The patient was referred to the department of urology for further examination of bilateral renal masses which were incidentally found on abdominal computed tomography (CT) and magnetic resonance-CT. Fine needle biopsy performed and microscopic examination revealed the presence of clear cell type renal cell carcinoma (grade 1). Renal arteriography demonstrated multiple neovascularity in the bilateral masses. Complete tumor excision was impossible to retain the minimum of renal function, the patient was conservatively subjected to a follow-up study.

Adult↗