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Y Kitaura

Publications and source records attributed to Y Kitaura.

At least 37 records · Page 2Linked to original sources
PubMed1995

Analysis of enterovirus genotypes using single-strand conformation polymorphisms of polymerase chain reaction products.

Enterovirus genotypes were identified rapidly by reverse (RT-PCR) followed by single-strand conformation polymorphism (SSCP) analysis. The primer pair was chosen from the highly conserved sequence at the 5' non-coding region of enterovirus genomes. RT-PCR amplified a 154 bp sequence in all samples from 14 serotypes of enteroviruses, including group A and B Coxsackie viruses, echoviruses and polioviruses. SSCP analysis of these products revealed different electrophoretic profiles. Thus, SSCP analysis will be useful for differentiating the genotypes of enteroviruses, and may be applicable for rapid diagnosis of enteroviral infection.

Base Sequence↗
PubMed1995

[Management of total laboratory system and its efficacy].

The Osaka City University Hospital was reopened in May 1993. In the Central Clinical Laboratory our Total Laboratory Automation System, a comprehensive online analyzing system, covers the entire process from collecting blood to completing tests. Our study showed that an average of 2,800 outpatients were examined per day in 1994, compared with 1,900 per day in 1992, an increase of 47.4%. The number of tests performed by the central laboratory in 1994 was 5,610,000 as compared to 3,720,000 in 1992, an increase of 50.8%. After the installation of the transport line and computerization the following can be noted: 1) We were able to extend reception hours by two hours. 2) We are now able to assign lab medical technologists to physiology analysis, emergency analysis, and initial outpatient testing. We conclude that these effects have been very large.

Clinical Laboratory Information Systems↗
PubMed1992

Ultrastructural alterations of the conduction system in mice exhibiting sinus arrest or heart block during Coxsackievirus B3 acute myocarditis.

By light and electron microscopy we studied the sinus nodes and atrioventricular (AV) conducting tissue of six C3H/He mice having coxsackievirus B3 acute myocarditis. Sinus arrest was documented in all six mice, and second- or third-degree AV block was documented in three of the six mice. Although myocarditic changes in the conduction system, especially in the sinus node, were less than those in atrial and ventricular working myocardium, there were distinct abnormalities within both the sinus node and AV conducting tissue in all six hearts. Important ultrastructural alterations were inflammatory cell infiltrates and significant injury of specialized cells and of neural tissue. Specialized cells showed various features of degeneration and necrosis. Neural tissue damage included degeneration of axons and Schwann cells and disorganization of the neuromuscular junctions. Inflammatory cells, particularly macrophages, were often in intimate contact with injured specialized cells and neural tissue. Interstitial edema and bleeding and lymphatic vessel dilatation were also observed. These pathologic changes are considered to play an important role in the development of the documented disturbances of rhythm and conduction.

Animals↗
PubMed1992

Genomic detection of enteroviruses in the myocardium--studies on animal hearts with coxsackievirus B3 myocarditis and endomyocardial biopsies from patients with myocarditis and dilated cardiomyopathy.

We examined myocardial tissues for the presence of enteroviral RNA in animal models with experimental coxsackievirus B3 myocarditis and in endomyocardial biopsy samples obtained from patients clinically diagnosed as having dilated cardiomyopathy or myocarditis using polymerase chain reaction (PCR) gene amplification with enterovirus-generic primers and/or coxsackievirus B3-specific primers. In animal models, coxsackievirus B3 was detected in myocardial tissues up to 28 days, 56 days and 180 days after inoculation, in C3H/He mice, A/J mice and Syrian golden hamsters, respectively. The viral genomes were identified by in situ hybridization in myocardial cells and some interstitial cells in and around the myocarditic lesions in animals. In human endomyocardial biopsy samples, enteroviral RNA sequences were detected in 8 (32%) out of 25 patients with clinical dilated cardiomyopathy and in 3 (33%) out of 9 patients with clinical myocarditis. The patients showing histologic findings of myocarditis and clinical features resembling dilated cardiomyopathy had a high incidence (83%) of positive PCR result for enteroviral RNA sequences. Additionally, 25% of patients with dilated cardiomyopathy showing no histologic findings of myocarditis had positive PCR result. This study supports a link between viral myocarditis and dilated cardiomyopathy.

Adult↗
PubMed1992

Viral genomic detection in the hearts of C3H/He mice with experimental Coxsackievirus B3 myocarditis by gene amplification using the polymerase chain reaction.

On the basis of the detection of the enteroviral RNA in the hearts of patients with healed myocarditis and dilated cardiomyopathy, we investigated cardiac viral persistence in experimental myocarditis. Weanling C3H/He mice were given myocarditis by inoculation with coxsackievirus B3 (Nancy strain), and their hearts were examined by genomic studies and viral isolation up to the 180th day after inoculation. The virus was isolated from the heart until the 9th day. By slot-blot hybridization, viral RNA was also only detected until the 9th day in the heart. Specific DNA amplification using the polymerase chain reaction (PCR) was performed after a reverse transcriptase reaction, then followed by Southern blot hybridization with a 32P-labelled oligomer probe. This technique achieved the type-specific detection of coxsackievirus B3 even at a level of less than one of the 50% tissue culture infective dose (TCID50). With this technique, viral RNA was detected up to the 28th day after inoculation. Thus, the viral RNA persisted in the hearts of these mice even when infectious virus could no longer be detected.

Animals↗
PubMed1991

Cell-mediated cytotoxicity in acute rat cardiac allograft rejection: an immunological and ultrastructural study.

To clarify the immune mechanism of cytotoxicity in acute cardiac allograft rejection, we observed interactions between cardiocytes and mononuclear cells using immunohistochemistry and light and electron microscopy. All allografted WKA rat hearts transplanted to F344 recipients stopped beating by the 7th day after the transplantation. The population of helper/inducer T cells (Th) and IL2R+ cells was large for the first 3 days, whereas that of cytotoxic/suppressor T cells (Tc-s) and macrophages increased from the 4th day. The Th/Tc-s ratios were more than 2.0 until the 3rd day, then decreased to less than 1.0. In circulating T lymphocytes; the Th/Tc-s ratios were under 1.0 on the 1st, 6th and 7th days. Electron microscopically IL2R+ cells, Tc-s and macrophages were often seen in close contact with the plasma membrane of the cardiocytes. The majority of IL2R+ cells are NK cells, Tc-s and Th. Of these, the population of Tc-s was small until the 3rd day. Thus, NK cells play a pivotal role in the early stage of the rejection, and Tc-s and macrophages then aggravate cell-mediated cardiocyte injury.

Animals↗
PubMed1991

[Viral myocarditis].

Explore the source record for details and available documents.

Cardiomyopathy, Hypertrophic↗
PubMed1990

Arrhythmias in Coxsackie B3 virus myocarditis. Continuous electrocardiography in conscious mice and histopathology of the heart with special reference to the conduction system.

In patients with acute myocarditis, arrhythmias constitute one of the crucial risk factors for morbidity and mortality. To clarify the incidences and the chronological features of arrhythmias and their correlation with the histopathology of the heart, we conducted continuous electrocardiography in an animal model of viral myocarditis, and light microscopy of the heart with special reference to the conduction system. Forty weanling C3H/He mice were divided into an inoculated group (IG) and a control group (CG), of 20 mice each. IG was injected intraperitoneally with coxsackie B3 virus and CG was injected with virus-free culture medium. Thin electrodes were implanted in their chest walls and connected with an electric impulse transmitting device so that they could move freely. ECGs were recorded continuously without anesthesia up to the 14th postinoculation day. The atrial and ventricular myocardium and the conduction system were studied by light microscopy. In CG, no arrhythmia was noted. In IG, various kinds of arrhythmias were documented. The incidences of the arrhythmia in the 20 mice were: sinus arrest 80%, second or third degree atrioventricular (AV) block 30%, premature atrial complexes 30%, premature ventricular complexes 20%, and ventricular tachycardia 10%. Arrhythmias were usually transient and recurrent, and the majority of them developed between the 6th and 13th day, when the histologic changes of the heart were greatest. There seemed to be a correlation between the kind of arrhythmias and the myocarditic lesions. Mice with sinus arrest or AV block developed histopathologic changes in the sinus node or AV conducting tissue, respectively. In the early stage of myocarditis, no inflammatory changes were apparent in the sinus node in the mice with sinus arrest.

Animals↗
PubMed1990

Experimental influenza A virus myocarditis in mice. Light and electron microscopic, virologic, and hemodynamic study.

To elucidate the heart involvement associated with influenza virus infection, the authors studied the hearts of influenza A/PR/8/34 virus-inoculated ICR mice by light and electron microscopy, cardiac catheterization, virus assay, and indirect immunofluorescence. Light microscopy showed small necrotic foci with inflammatory cell infiltration spreading in the myocardium on days 3 to 7 and evidence of healing by day 9 after inoculation. Electron microscopy demonstrated that necrotic cell debris was phagocytosed by macrophages, and that degenerating cardiocytes, macrophages, and lymphocytes were often in close contact, suggesting immunologic interactions, and that platelet thrombi were present in some capillaries on days 3 to 5. Both systolic and diastolic functions of the left ventricle (LV) were impaired on days 3 to 9 and recovered almost to normal by day 14. The virus could be isolated from the heart on days 3 to 7. Immunofluorescent preparations showed virus antigens in the vascular walls and cardiocytes until day 7. These results suggest that the acute cardiac injury was related to cytotoxic immunologic interactions, virus-induced cytolysis and, at least in part, to ischemia due to intracapillary thrombosis. Compared with coxsackie B3 myocarditis in mice, the influenza myocarditis was mild in degree and short in duration, but the influenza infection is a most common and repetitive disease in humans. The clinical implications of this animal model with myocarditis are discussed.

Animals↗
PubMed1989

Cell-mediated immune cardiocyte injury in viral myocarditis of mice and patients.

The cellular immune mechanism of cardiocyte injury in viral myocarditis was investigated by observing and analyzing the interactions among cardiocytes, T cells, B cells, natural killer (NK) cells and macrophages in situ in the myocardium of our murine model (C3H/He mice) and of human patients. In murine coxsackie B3 virus myocarditis, lymphocyte subsets were identified by light and electron microscopic immunohistochemical techniques with antibodies against specific antigens of pan T (Thy 1.2), helper/inducer T (Th/i) (Lyt 1+), cytotoxic/suppressor T (Tc/s) (Lyt 2+), B (Ig+) and asialo GM1+ cells in the myocardium. In the acute phase of myocarditis, asialo GM1+ (mostly NK) cells predominated over pan T cells and peaked on day 9. Pan T cells then reached a peak on day 14. The T4/T8 (Lyt 1+/Lyt 2+) ratio was 1.3 +/- 0.5 on day 5 and reached a peak of 9.1 +/- 3.6 with an increase of Lyt 1+ cells on day 14. Thereafter, NK cells and T cells gradually decreased and could still be seen in fibrotic foci even 3 and 12 months later. B cells were so scarce that no quantitative evaluation could be made. Electron microscopy revealed that macrophages were in close contact with Th/i cells, target cardiocytes and less commonly, B cells; Tc/s and NK cells also occasionally conjugated with apparently viable or degenerated cardiocytes. Some lymphocytes were located in widened intercellular spaces of dissociated intercalated discs, and in intracytoplasmic widened confines of some cardiocytes (emperipolesis). These results suggest that in the acute phase of myocarditis, NK cells initiate the reaction, and then sensitized cytotoxic T cells and activated macrophages aggravate cell-mediated injury by their close contacts with target cardiocytes; close contacts among macrophages; Th/i cells and a few B cells, and the increased T4/T8 ratio may facilitate regulation of the complex immune network; in the chronic phase, residual but active NK and cytotoxic T cells may sustain cytotoxicity. In the endomyocardial biopsies obtained from 8 patients with viral or idiopathic myocarditis from 3 to 48 days after the clinical onset, conventional electron microscopy revealed actual contacts among cardiocytes, macrophages and lymphocytes. As in our murine model, some lymphocytes had emperipolesed in cardiocytes or were located in widened spaces of dissociated intercalated discs. In 4 of these 8 patients infiltration of Leu 2a+ Tc/s, Leu 3+ Th/i and Leu 7+ cells was identified immunohistochemically, and T4/T8 ratios varied widely from 0.1 to 3.8 in the endomyocardial biopsides.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1987

Functional and histopathologic correlation in patients with dilated cardiomyopathy: an integrated evaluation by multivariate analysis.

To correlate left ventricular function and histologic features in patients with dilated cardiomyopathy, precise indexes of hemodynamics and semiquantitative histologic data were combined for multivariate analysis. Right endomyocardial biopsy was performed at the time of cardiac catheterization. Five hemodynamic indexes were used for functional assessment: ejection fraction, ratio of end-systolic stress to volume index, end-diastolic stress, time constant (T) of left ventricular pressure fall, and end-systolic stress. Six histologic findings (disarray of myofibers, hypertrophy of myofibers, scarcity of myofibrils, nuclear changes of myofibers, vacuolization of myofibers and proliferation of collagen fibers) were graded from (-) to (4+). Each finding was assigned to category (-) or (+) according to the absence or presence of significant abnormality. Ordinary statistical analysis revealed that, although ejection fraction was lower in category (+) for proliferation of collagen fibers, ratio of end-systolic to volume index was reduced for category (+) of hypertrophy of myofibers. A significant correlation was present between hypertrophy of myofibers and proliferation of collagen fibers by Spearman rank correlation. When principal component analysis was applied to the hemodynamic data, two principal components could be extracted. Fisher's discriminant analysis could clearly differentiate two categories (-) and (+) in the semiquantitative histologic finding of proliferation of collagen fibers. The analysis indicated that contractility was reduced with elevated afterload in that category (+). Thus, proliferation of collagen fibers may play a pivotal role in deteriorating contractility in patients with dilated cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed1987

In situ analysis with monoclonal antibodies of lymphocyte subsets in myocardial biopsies from patients with dilated cardiomyopathy and idiopathic (viral) myocarditis.

This light- and electron-microscopic immunohistochemical study using monoclonal antibodies analyzes of the in situ lymphocyte subsets in endomyocardial biopsies from 11 patients with dilated cardiomyopathy (DCM) and three patients with idiopathic (viral) myocarditis (MYO). In the DCM patients both Leu 2a+ cytotoxic/suppressor T cells (Tc/s) and Leu 3+ helper/inducer T cells (Th/i) were identifiable in the myocardial lesions, and mean Th/i/Tc/s (T4/T8) ratio was 0.7 +/- 0.6 (mean +/- SD). In 9 of the 11 DCM patients, Tc/s were more numerous than Th/i cells, so the T4/T8 ratio was less than 1.0. On the other hand, the T4/T8 ratios varied widely in the three MYO patients; one of them had marked mononuclear cell infiltrates with many Th/i in the inflammatory foci and a T4/T8 ratio of 2.6. Immunoelectron microscopy revealed some Th/i in close contact with macrophages. These T cells in the myocardium of DCM and MYO patients appeared to be in vivo effector cells playing an important role in cell-mediated immune responses.

Adult↗
PubMed1987

Intravenous isosorbide dinitrate infusion in the management of unstable angina pectoris refractory to conventional medical therapy.

During the past 2 years, 102 patients were treated for unstable angina pectoris (AP) in our department. Fifteen of them had recurrent chest pain at rest despite treatment with various anti-anginal agents, or prolonged chest pain unresponsive to sublingual nitroglycerin; they received intravenous isosorbide dinitrate (ISDN) infusion. A rapid bolus injection of 2 to 6 mg followed by an infusion of 2 to 5 mg/hr was given to 10 patients with acute chest pain, and 5 patients, who were free of chest pain at the time, but had repeated episodes of angina in the past 24 hours, were given ISDN infusion without a bolus injection. Chest pain disappeared completely in 13 patients, but recurred in 2 of them when the dose was tapered. Two other patients experienced recurrent chest pain during ISDN infusion, and additional boluses were given. The hospital course was uneventful in 11 patients. Four patients who had recurrent anginal attacks underwent emergency coronary cineangiography under intraaortic ballon counterpulsation and aorto-coronary bypass surgery. There were no hospital deaths, no one had subsequent acute myocardial infarctions, and only 2 patients had mild to moderate headache as a side effect. Although the patient population is small, intravenous ISDN infusion is useful in the management of severe unstable AP.

Acute Disease↗
PubMed1986

Small hepatocellular carcinomas in chronic liver disease: detection with SPECT.

Single-photon emission computed tomography (SPECT) performed using a rotating gamma camera was compared with alpha 1-fetoprotein (AFP) assay, conventional liver scintigraphy, ultrasound (US) imaging, computed tomography (CT), and selective celiac angiography in 40 patients with a total of 50 small hepatocellular carcinomas (HCCs; less than 5 cm). The detection rates of US and CT were determined on an initial screening study and on a second, more precisely focused study. The detection rate of small HCCs by the various modalities was as follows: AFP, 13%; liver scintigraphy, 36%; SPECT, 72%; initial screening US, 80%; second, more precise US studies, 94%; initial screening CT, 64%; second, more precise CT study, 82%; angiography, 88%. Although SPECT was inferior to the initial screening US examination in detecting HCCs less than 2 cm in size, its sensitivity was identical to that of the initial screening US study for detecting HCCs of 2-5 cm. The combination of SPECT and US was an excellent method for the early detection of HCCs, yielding a detection rate of 94%.

Aged↗