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Biomedical subjects

S Yagi

Publications and source records attributed to S Yagi.

At least 163 records · Page 9Linked to original sources
PubMed1993

Inhibition of protein synthesis and antiproliferative effect of the angiotensin converting enzyme inhibitor trandolaprilat in rat vascular smooth muscle cells.

OBJECTIVE: To investigate the effect of the angiotensin converting enzyme (ACE) inhibitor trandolaprilat on vascular smooth muscle cell growth, and to analyse its mechanism of action. DESIGN: Aortic vascular smooth muscle cells (VSMC) from Wistar-Kyoto rats were cultured, and cell proliferation was analysed using a cell synchrony technique. METHODS: Proliferative activity was assessed by [3H]-thymidine uptake and doubling time. Protein synthesis was assessed by [3H]-leucine incorporation. Actin formation was measured using sodium dodecylsulphate-polyacrylamide slab gel electrophoresis and a densitometric assay. The effect of trandolaprilat on translational protein synthesis was also examined using the cell-free protein synthesis system of reticulocyte lysate and messenger RNA from VSMC. RESULTS: Trandolaprilat decreased [3H]-thymidine uptake and increased the doubling time of randomly cycling VSMC. The cell synchrony study revealed that this antiproliferative effect was due to increased transition time from S to G2-M. Decreased cell cycle progression during G2-M was reflected by inhibition of cellular protein synthesis during this period. Cellular protein in randomly cycling VSMC was also decreased by trandolaprilat. This decreased protein synthesis was probably produced by inhibition of RNA translation. CONCLUSIONS: The ACE inhibitor trandolaprilat reduces VSMC proliferation by lengthening the G2-M phase of the cell cycle, and produces a decrease in cellular protein content. This effect is probably mediated by inhibition of protein synthesis at the translational level.

Actins↗
PubMed1993

Ultrastructural studies on the Ca2+ localization in the dividing cells of the maize root tip.

The distribution of Ca2+ in dividing cells of the maize root tip was examined by potassium pyroantimonate precipitation and EGTA treatment methods. Ca2+ was found in most of the cell organelles, such as the matrix of the mitochondria, the thylakoid membrane of the proplastid and the Golgi vesicles, and on the plasma membrane. Ca2+ was also distributed throughout the cytoplasmic ground matrix and attractoplasm, inside the vacuoles, in the granular zone of the nucleolus in the interphasic nucleus and in the regenerated nucleolus in the telophasic nucleus. The amounts of Ca2+ distributed in the cytoplasmic ground matrix, the vacuole and the nucleolus varied during nuclear division. From the results of the present experiment, the following considerations on the role of Ca2+ and the regulation site of Ca2+ in dividing plant cells were drawn: 1) Ca2+ may play a role in the construction of the granular form of the ribosome. 2) Ca2+ may be an essential ion in the regeneration of nucleolus. 3) Vacuoles may act as the regulatory site of the Ca2+ concentration in the cytoplasm and attractoplasm in plant cells. Spindle microtubules and phragmo-microtubules are probably surrounded by other ions, such as Mg2+.

Antimony↗
PubMed1993

Spatial orientation of the vectorcardiogram in patients with myocardial infarction.

We studied the rotation angles on the each of 3 axes and the planarity and roundness of QRS loop when its plane was laid close to horizontal in 4 groups of patients. Thirty five had anterior myocardial infarction, 34 inferior infarction, 15 non Q wave inferior infarction, and 34 were normal subjects. The rotation angles of the QRS loop were significantly different from the controls, on the Y and Z axes in the anterior infarction group, on the Z axis in the inferior infarction group and on the X axis in the non Q wave inferior infarction group (p < 0.01). The planarity index in the inferior infarction group was significantly higher (p < 0.01) than in other groups. The significantly smallest value of the roundness index was noted in the anterior infarction group (p < 0.01). Significant features of the early segmental planarity indexes were shown in the non Q and Q wave inferior infarction groups (p < 0.01). We conclude that the rotation angles and the planarity and roundness indexes are characteristic parameters for the infarct group and may be useful for diagnosing myocardial infarction, which is difficult with electrocardiography and vectorcardiography.

Adult↗
PubMed1993

New interpretation of systolic time intervals from active cross-bridge model.

Using an active cross-bridge model proposed by the authors, it has been established theoretically that cross-bridge activation rate (Ka) of the left ventricular myocardium, which might correspond to the rate of binding of Ca2+ with troponin C, is approximately expressed as a simple formula: Ka = 3/electromechanical systole (sec-1), although no definitive biological proof has yet been provided for the equation. One hundred eighteen patients without significant cardiac disease and 6 patients who had atrioventricular block with a permanent pacemaker were evaluated to determine the Ka value of the normal human left ventricular myocardium (test 1), and to examine the effect of changes in heart rate (test 2) as well as afterloading (test 3) or dobutamine infusion (test 4) on Ka. The pacing rate was increased from 50 to 110 beats/min at 20-beat increments in test 2. Arterial pressure was elevated by angiotensin II infusion in test 3, and 7 subjects received a continuous dobutamine infusion in test 4. The Ka value was found to be related to heart rate, to be increased by dobutamine infusion, and to be decreased by myocardial lengthening due to afterloading. Dependence of Ka on heart rate appeared to result from changes in myocardial length. The Ka value corrected for heart rate (Kac) had an average variation of only 4.6%, and was unrelated to age or myocardial length in individual subjects. Thus, the Kac value of normal human left ventricular myocardium appears to be nearly constant between individuals but to be increased by catecholamine infusion or myocardial shortening.

Adult↗
PubMed1993

Effect of isosorbide dinitrate infusion on the canine left ventricular force-length relationship.

Recently, the slope (Ec) of the left ventricular (LV) end-systolic force-diameter (Fes-Des) relationship has been proposed as a new index for assessing myocardial contractility. Using this relationship, the effects of ISDN on LV myocardial contractility were evaluated in 10 healthy adult mongrel dogs. After the intravenous infusion of propranolol and atropine to produce autonomic blockade, the inferior vena cava was gradually occluded for 20 sec to decrease preload while the dogs were kept apneic. The LV diameter was measured by ultrasonic crystals and LV pressure was measured by a micromanometer. After the control measurements, the dogs received intravenous ISDN (1, 5, 10, or 50 micrograms/kg/min), and inferior vena caval occlusion was repeated. Ec and the extrapolated diameter intercept (D0) of the LV Fes-Des relationship were determined for each dog from the end-systolic data. The differences in heart rate between the control state and ISDN infusion at any dose were not statistically significant. The Ec and D0 values also showed no significant changes with ISDN infusion (Ec: 80 +/- 19, 83 +/- 20, 84 +/- 17, 82 +/- 24, and 87 +/- 24 g/cm for 0, 1, 5, 10, and 50 micrograms/kg/min, respectively. D0: 1.38 +/- 0.42, 1.38 +/- 0.40, 1.38 +/- 0.38, 1.34 +/- 0.40, and 1.36 +/- 0.40 cm for 0, 1, 5, 10, and 50 micrograms/kg/min, respectively). These findings suggested that intravenous ISDN did not affect myocardial contractility in the normal in situ canine left ventricle.

Animals↗
PubMed1993

Adrenocortical carcinoma with a giant pericardial mass.

A patient with a history of adrenocortical carcinoma presented with massive pericardial effusion and a giant pericardial mass. Death resulted from cardiac tamponade. At autopsy a large necrotic mass was histologically similar to the original adrenocortical carcinoma. We present this case and review the literature on metastatic pericardial disease.

Adrenal Cortex Neoplasms↗
PubMed1993

[Clinical usefulness of newly developed urine protein dipstick (URINE-TP)].

We assessed the clinical usefulness of a newly developed urine protein dipstick (URINE-TP; U-TP) which can detect gamma-globulin and other proteins as well as albumin. Semiquantitative values of urine protein evaluated with U-TP were compared with those evaluated with ordinary urine protein dipsticks (BM-TEST) in 966 urine samples. The two tests showed the same semiquantitative values in 572 of 966 samples (59.2%; Group A). However, U-TP showed a more positive reaction two gradations higher in 89 samples (9.2%; Group B), and showed a more positive value with one gradation higher in 283 samples (29.3%; Group C) compared with BM-TEST. We then measured total protein, alpha 1-microglobulin (alpha 1-M), NAG and beta 2-microglobulin (beta 2-M) in urine, and serum beta 2-M, urea nitrogen (UN) and creatinine (CRE) in both Group A and Group B. In BM-TEST negative patients, urinary total protein, tubular proteins (alpha 1-M, beta 2-M) and NAG were significantly higher (p < 0.01) in Group B than in Group A. Moreover, among patients who had trace or positive results by BM-TEST, serum UN was significantly higher (p < 0.01) in Group B than in Group A. These results suggest that U-TP, a newly developed urine protein dipstick, can detect tubular proteins which cannot be detected by ordinary dipsticks. U-TP may be useful for early detection of renal tubular damage, especially when use is the combined with conventional dipsticks.

Acetylglucosaminidase↗
PubMed1993

[The left ventricular force-length relationship in patients with heart failure].

A new contractility index (Ec) is proposed based on the slope of the left ventricular (LV) end-systolic force-length relationship. The Ec values of normal human hearts are relatively constant. The present study investigated the Ec values of 16 cases of heart failure in 11 patients with old myocardial infarction and 5 with dilated cardiomyopathy in NYHA functional class 1 to 3. The LV end-systolic pressure (Pes) and dimension (Des) were estimated simultaneously by intraarterial cannulation and LV echocardiography. The LV pressure decreased from 111 +/- 17 to 90 +/- 14 mmHg after intravenous infusion of nitroglycerin. The LV Fes-Des relationship was found to be nearly linear and the slope (Ec) and extrapolated dimension intercepts (Do) were obtained as 60 +/- 22 g/cm and 2.7 +/- 1.2 cm, respectively. The values of Ec and Do were both proportional to the baseline Des value. Our model predicts that the Ec value reflects intracellular peak Ca2+ concentrations ([Ca2+]) of the myocardium and/or myosin ATPase activity. The present results suggest that the working myocardium of a failing heart increases [Ca2+] and/or myosin ATPase activity to compensate for depressed LV pump function due to myocardial damage.

Adult↗
PubMed1993

[Effects of nisoldipine in heminephrectomized spontaneously hypertensive rats--measurement of afferent and efferent arterioles by microvascular cast].

In this study, we measured cross sectional areas of glomerular arterioles and glomerular volume in heminephrectomized spontaneously hypertensive rats (SHR) treated with a calcium antagonist, nisoldipine (NSL). We also examined the relevance of these parameters to the progression of hypertensive renal injury. Male 6-week-old SHR (n = 14) were heminephrectomized and divided into 2 groups. They were fed regular chow (control, n = 7) or chow containing 0.1% NSL (n = 7). After 12 weeks, urinary protein excretion (UpV) and systolic blood pressure (SBP) were measured. The control rats developed marked hypertension reaching 228 +/- 2 mmHg, and NSL lowered this by 27 mmHg (p < 0.001). NSL reduced UpV by 22% (p < 0.05). Microvascular cast of the kidney was prepared, and the cross sectional areas of the afferent and efferent arterioles as well as glomerular volume were measured using scanning electron microscopy. In the juxtamedullary and subcapsular glomeruli with minor abnormalities, the afferent arteriole was narrower and the glomerular volume was smaller in the NSL-treated rats than in the control rats. These results suggest that the calcium antagonist, NSL, offers the advantage of protecting kidney from hypertensive injury by reducing afferent arteriolar diameter, glomerular hypertrophy and intraglomerular pressure in heminephrectomized SHR.

Animals↗
PubMed1993

[Efficacy and safety of long-term erythropoietin therapy in chronic hemodialysis patients with renal anemia].

In order to examine the efficacy and safety of long-term erythropoietin (rHuEPO) therapy, 103 hemodialysis patients were treated with rHuEPO for their renal anemia and the effects were observed for 1 year. Within 3 or 4 months after starting the rHuEPO therapy, the hematocrit (Ht) value rose up to nearly 30% and the level was maintained thereafter by approximately 4500 IU per week of rHuEPO. Tachyphylaxis did not occur even after 1 year of rHuEPO treatment. Symptoms such as headache, dizziness or palpitation were markedly reduced with the improvement of anemia. Although blood pressure was modestly elevated (systolic by 9 mmHg, p < 0.01 and diastolic by 5 mmHg, p < 0.01 at 6-month-stage), only 1 patient was forced to stop the therapy. Moreover, the blood pressure was successfully controlled to the original level after 11 months. This blood pressure elevation was not related to the increase of Ht level nor the dose of rHuEPO. Serum protein, lipid, electrolytes and liver enzymes did not change during 1 year of rHuEPO therapy. These results indicate that rHuEPO treatment is effective and innocuous as a long-term therapy of renal anemia in hemodialysis patients.

Anemia↗
PubMed1993

[Management of the severe calcified ascending aorta during coronary bypass surgery].

The best management of the calcified ascending aorta during coronary surgery has not established. Clamping of the calcified aorta causes cerebral embolism, aortic rupture and laceration as a lethal complication. Recently we had two successful cases of surgical treatment and these were treated by "Non-touch aortic technique". The femoral cannulation and ventricular fibrillation with moderate hypothermia or circulatory arrest will reduce the risk of coronary bypass surgery in the calcified aorta.

Aged↗
PubMed1992

Antigen responsive antibody-receptor kinase chimera.

We have constructed chimeric receptors, combining murine IgM and the cytoplasmic portion of human epidermal growth factor receptor (EGFR), with the aim of developing a novel immunosensor with antigen-dependent phosphorylation activity. When intact IgM was used, the chimeric receptor showed both antigen binding and protein tyrosine kinase activity, but the kinase activity was constitutive and independent of antigen binding. However, with IgM lacking the CH2 domain, the autophosphorylation activity increased with increasing concentrations of anti-IgM or hapten-BSA conjugate. Monovalent hapten could not induce phosphorylation but inhibited stimulation by hapten-conjugated BSA.

Animals↗
PubMed1992

OPC-13340, a new dihydropyridine calcium channel blocker attenuates rapid vascular smooth muscle cell growth in spontaneously hypertensive rats.

We investigated the mechanism of the antimitotic effects of calcium channel blockers in vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR). VSMC from SHR exhibited rapid proliferation through a quick transition from the G0/G1 to the DNA synthetic (S) phase and from the S to the G2/mitotic (M) phase, whereas the DNA synthetic rate itself was equal to that of Wistar-Kyoto rats (WKY). OPC-13340, a new dihydropyridine calcium channel blocker, dose-dependently decreased incorporation of [3H]thymidine into the DNA fragments in randomly cycling VSMC in SHR. Cell cycle analysis showed that the rapid transition from the S to the G2/M period was restored by OPC-13340 to the control level in WKY, whereas the quick transition from G0/G1 to S was unaffected. This antimitotic effect of OPC-13340 was reflected by attenuation of enhanced cellular protein synthesis during the G2/M period. Protein synthesis in the G0/G1 period was not influenced by OPC-13340. Thus, these data indicate that the calcium channel blocker OPC-13340 mitigates the enhanced proliferation observed in randomly cycling VSMC from SHR and that this effect is primarily due to normalization of the premature mitosis during the G2/M period.

Animals↗
PubMed1992

Pantoea punctata sp. nov., Pantoea citrea sp. nov., and Pantoea terrea sp. nov. isolated from fruit and soil samples.

A total of 37 bacterial strains with the general characteristics of the family Enterobacteriaceae were isolated from fruit and soil samples in Japan as producers of 2,5-diketo-D-gluconic acid from D-glucose. These organisms were phenotypically most closely related to the genus Pantoea (F. Gavini, J. Mergaert, A. Beji, C. Mielearek, D. Izard, K. Kersters, and J. De Ley, Int. J. Syst. Bacteriol. 39:337-345, 1989) and were divided into three phenotypic groups. We selected nine representative strains from the three groups for an examination of DNA relatedness, as determined by the S1 nuclease method at 60 degrees C. Strain SHS 2003T (T = type strain) exhibited 30 to 41 and 28 to 33% DNA relatedness to the strains belonging to the strain SHS 2006T group (strains SHS 2004, SHS 2005, SHS 2006T, and SHS 2007) and to the strains belonging to the strain SHS 2008T group (strains SHS 2008T, SHS 2009, SHS 2010, and SHS 2011), respectively. Strain SHS 2006T exhibited 38 to 46% DNA relatedness to the strains belonging to the strain SHS 2008T group. The levels of DNA relatedness within the strain SHS 2006T group and within the strain SHS 2008T group were more than 85 and 71%, respectively. Strain SHS 2003T, SHS 2006T, and SHS 2008T DNAs exhibited less than 18% binding to Pantoea dispersa ATCC 14589T and Pantoea agglomerans ATCC 27155T DNAs.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Composition↗
PubMed1992

The origin of myoclonus and periodic synchronous discharges in subacute sclerosing panencephalitis.

We report here a case of a patient with subacute sclerosing panencephalitis (SSPE) and we have analyzed periodic events using dipole tracing methods to clarify the origin of periodic synchronous discharges and myoclonus. Both source generators were located in the subcortical part of the cerebrum, an area adjacent to the thalamus. Although the pathophysiology of periodic events in SSPE has been controversial, dipole tracing methods may contribute to clarify the origin of periodic events in SSPE.

Action Potentials↗
PubMed1992

Spectrum of monoclonal antibodies to coxsackievirus B-3 includes type- and group-specific antibodies.

Fifteen monoclonal antibodies (MAbs) made to coxsackievirus B-3 were tested against a panel of enteroviruses by indirect immunofluorescence. The MAbs included seven which reacted with coxsackievirus B-3 only, five which reacted with more than one enterovirus included in the panel, one which reacted with broad enteroviral specificity and did not react with any heterologous virus (group specific), and two which reacted with all enteroviruses tested and at least one heterologous virus. The group-specific MAb identified 44 of 45 clinical isolates as enteroviruses, while the two broadly reactive MAbs reacted with all 45 of the clinical isolates. These MAbs are potentially important diagnostic reagents for grouping and typing enteroviruses by indirect immunofluorescence.

Antibodies, Monoclonal↗