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Biomedical subjects

K Moriyama

Publications and source records attributed to K Moriyama.

At least 163 records · Page 9Linked to original sources
PubMed1991

Biventricular down-regulation of beta-adrenergic receptors in right ventricular hypertrophy induced by monocrotaline.

To investigate the changes in beta-adrenergic receptors in the right and left ventricles during the development of cardiac hypertrophy, right ventricular hypertrophy (RVH) was induced in rats by a single injection of monocrotaline (M) (60 mg/kg). The rats demonstrated RVH at 2 weeks and severe RVH with congestive heart failure at 4 weeks after the injection. Changes in the beta-adrenergic receptors in the membrane fractions of both ventricles were examined in the M-treated vs. control rats using 125I-iodocyanopindolol (ICYP). Plasma and tissue catecholamines were measured. Plasma levels of norepinephrine (NE) and epinephrine (EP) showed no change at 2 weeks after the injection. However, at 4 weeks there was a significant increase in NE (p less than 0.01), but not in EP. There was no significant change in NE or EP in either ventricle at 2 weeks vs. the controls. However, at 4 weeks there was a significant increase in both NE and EP in the right ventricle (RV) (p less than 0.05). NE in the left ventricle (LV) tended to increase, but not a significant extent (p less than 0.1). With the development of RVH at 2 weeks, the maximum number of binding sites (Bmax) in both the RV and LV showed a significant decrease (p less than 0.01). There was a 21% decrease of Bmax in the RV and 15% in the LV at 2 weeks vs. the controls. At 4 weeks, the changes in Bmax were more prominent, with a 57% decrease in the RV and 22% in the LV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Effect of diabetes mellitus on levels of atrial natriuretic hormone in plasma and the right atrium in the non-obese diabetic mouse.

Atrial natriuretic hormone (ANH) levels in plasma and the right atrium of non-obese diabetic mice in the decompensated diabetic state were investigated by radioimmunoassay and histological examination. Severely diabetic mice, with blood glucose levels over 33.6 mmol/l showed significantly higher hematocrit, plasma sodium and calculated plasma osmolarity than the age-matched normoglycemic mice. The plasma ANH levels in diabetic mice were significantly lower (17.5 pmol/l) than those in normoglycemic mice (43.6 pmol/l). The ANH concentrations in the right atrium were 26.6 mg/g protein in the diabetic and 11.2 mg/g protein in the normoglycemic mice. The right atrium in the diabetic mice showed much wider immunohistochemical staining by anti-human ANH antiserum compared with the normoglycemic mice. An increase in the number of atrial specific granules in the diabetic mice was observed by transmission and scanning electron microscopy. Morphometrical analysis indicated that the number of granules increased to more than twice that in the normoglycemic mice. These findings indicate that plasma ANH decreases in diabetic mice. The store of right atrial ANH may be increased to compensate for the marked dehydration in severe diabetes.

Animals↗
PubMed1991

Caffeine-induced contraction of rat portal vein and effects of K-depolarization, Na-removal and low temperature.

Contribution of Ca influx from extracellular pool and Ca-release from store sites in caffeine-induced contraction of rat portal vein longitudinal muscle were examined. At 37 degrees C caffeine induced a phasic contraction and the contraction was inhibited by verapamil or in the absence of Ca. Under low temperature, it was not decreased remarkably by verapamil or by the removal of extracellular Ca. Na-removal potentiated caffeine-induced contraction in the absence of Ca. Caffeine-induced contraction was also potentiated by high-K-depolarization. These contractions were at both temperature inhibited greatly by ryanodine. Caffeine induced the burst of the action potential at 37 degrees C but it was not remarkable at 17 degrees C. These results indicate that both extracellular Ca influx and release of stored Ca are involved in the caffeine-induced contraction. However, dependence of the contraction on Ca sources are influenced by temperature, extracellular Na and membrane potential.

Action Potentials↗
PubMed1991

[Factors regulating venous return: analysis based on the respiratory variations of superior vena caval flow].

Characteristics of venous return and its determining factors were observed using pulsed Doppler echocardiography. Superior vena caval (SVC) flow was regarded as representing venous return. Ten healthy subjects and 23 patients with chronic pulmonary disease were studied. 1. In the healthy subjects, the forward flow was biphasic with dominant systolic (S) wave. Among 23 patients, 18 had normal SVC flow patterns (Group I), while in the remaining 5, SVC flow showed disappearance of the diastolic (D) wave, or both the D and S waves (Group II). 2. The healthy subjects and Group I patients had negative pleural pressures during inspiration and expiration. Consistent findings in Group II patients included positive pleural pressures during expiration and reduction in FEV1.0%. In the normal subjects and Group I patients, right atrial (RA) pressure was less than the pressure of the subclavian vein (ScV) during an entire respiratory phase. However, in Group II, RA pressure was equal to or greater than ScV pressure during expiration, resulting in disappearance or reversal of the S and D waves. 3. Respiratory variation in pleural pressure correlated significantly with that of the S wave (r = 0.77) (p < 0.005), D wave (r = 0.80) (p < 0.005), x descent of RA pressure (r = 0.77) (p < 0.005), and y descent of RA pressure (r = 0.82) (p < 0.005). The present study clearly confirmed that the superior vena caval flow patterns were closely correlated with right heart hemodynamics and truly reflected the effects of pleural pressure.

Aged↗
PubMed1991

[Venous return disturbances in chronic pulmonary disease: a study using pulsed Doppler echocardiography].

Pulsed Doppler echocardiography was used for investigation of respiratory changes of superior vena caval flow in chronic pulmonary disease to analyze the mode of venous return and its regulating factors. The subjects consisted of 55 patients with various pulmonary diseases and 44 healthy controls. 1. In the controls, the velocities of the S and D waves increased during the inspiratory phase. 2. Patients with pulmonary diseases were categorized into 2 groups. One with the mode of the healthy subjects (normal pattern), and the other with disappearance of the D wave or both the S and D waves (abnormal pattern) in the expiratory phase. All patients with restricted ventilation exhibited the normal patterns, while the abnormal patterns were observed in some of the patients with obstructive ventilation, and most of the patients with combined ventilation. 3. The respiratory patterns of the pressure gradients between the right atrium and subclavian vein reflected patterns of the superior vena caval flow well. In cases with abnormal patterns, the right atrial pressure exceeded the subclavian vein pressure in the expiratory phase. 4. The velocity of the A wave at the expiratory phase correlated significantly with pulmonary vascular resistance and with the mean pulmonary artery pressure. In conclusion, the mode of venous return in patients with pulmonary disease varies depending on the mode of the ventilation disturbance and the presence of right ventricular pressure overload, which is most likely caused by the intrathoracic pressure and by right ventricular filling abnormalities.

Aged↗
PubMed1991

[Body surface isopotential mapping system by colored spatial mapping electrocardiography].

We developed a new body surface isopotential mapping system using a colored spatial mapping electrocardiographic technique based on Frank's vectorcardiography to be used with CERX CQ-3011 and NEC PC-100 computers. We assessed its usefulness in comparison with the conventional body surface mapping technique in 12 patients with old myocardial infarction (6 with anterior and 6 with inferior infarction), and in 10 healthy subjects. All distributions of positive and negative zones presented on body surface isopotential maps were obtained with this new technique, which corresponded well with the distribution of zones on conventional body surface isopotential maps. Although the maximum and minimum positions of the 2 maps did not coincide with one another, this new map aided in diagnosing anterior and inferior infarction from the minimum position determined 20 msec after the onset of QRS. This new mapping system allows a clear spatial representation of vectorcardiograms and requires less complicated procedure compared with the conventional body surface mapping technique. Thus, this body surface isopotential mapping system should be clinically useful.

Adult↗
PubMed1991

[Long survival in a case of metastatic brain tumor].

A 45-year-old man was admitted after resection of a metastatic brain tumor (papillary adenomatous adenocarcinoma, well differentiated) for both therapy and a search for the primary and any other metastatic lesions. An extensive general examination revealed no evidence of malignant lesion except for fibrous change in the right lung apex by roentgenography and CT scan. Histological examination of the right upper lobe and group II lymph nodes revealed a scar cancer presenting the same histology but no evidence of metastasis. The patient, who received CAP and FVM alternately, is currently healthy with no recurrence after 4 years.

Adenocarcinoma↗
PubMed1990

Destrin, a mammalian actin-depolymerizing protein, is closely related to cofilin. Cloning and expression of porcine brain destrin cDNA.

Destrin is a mammalian 19-kDa protein that rapidly depolymerizes F-actin in a stoichiometric manner. In this study, we isolated cDNA clones coding for destrin from a porcine brain cDNA library. The deduced amino acid sequence of destrin is 165 residues long and is very similar (71% identical) to that of cofilin, a widely distributed, pH-sensitive actin-modulating protein. Destrin contains a sequence nearly identical with the putative nuclear transport signal sequence of cofilin and a hexapeptide sequence identical with the amino-terminal sequence (residues 2-7) of tropomyosin, which is shown to be involved in cofilin binding to actin. Destrin, like cofilin, also has in its carboxyl-terminal portion a region homologous to the sequence shared by gelsolin, fragmin, and Acanthamoeba profilin. We have expressed destrin as well as cofilin in Escherichia coli, purified them, and examined their function in vitro. The two proteins were found to differ in their interaction with actin, like destrin and cofilin isolated from porcine brain. This suggests that the difference in the function of the two proteins results from the subtle difference in their amino acid sequence rather than possible differences in post-translational modifications. Northern blot analyses indicated that both destrin mRNA and cofilin mRNA are widely distributed in various tissues, but both mRNAs differ in their relative abundance among tissues.

Acanthamoeba↗
PubMed1990

Superior vena cava syndrome as a complication of DDD pacemaker implantation.

A 75-year-old man was admitted to our hospital because of swelling of the face and neck 6 months after implantation of a two-chamber pacemaker. Digital subtraction angiography showed total occlusion of the superior vena cava vein and well-developed collateral channels. After thrombolytic therapy, facial swelling disappeared. Digital subtraction angiography performed after thrombolytic therapy revealed a recanalization of the superior vena cava.

Aged↗
PubMed1990

Relaxation of mesenteric artery of stroke prone spontaneously hypertensive rats by calcium removal.

1. The time courses of the relaxation, induced by removal of extracellular Ca2+, of K-depolarized mesenteric artery preparations from stroke prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto rats (WKY) were compared. 2. The time course of the decline in extracellular Ca2+ was estimated from the time course of the relaxation and the concentration-response curve of K(+)-depolarized preparations to Ca2+. The time course of the decline in the intracellular free Ca2+ concentration was also estimated from the reported relation between Ca2+ concentration and the contraction of skinned vascular smooth muscle. 3. The time course of relaxation was exponential, the curve being made up of three components. The time course was slower in preparations from SHRSP, especially the first component of the relaxation curve. 4. The time courses of the decline in the intracellular and extracellular Ca2+ concentrations were also exponential, being made up of three components and were also slower in the preparation made from SHRSP. 5. The wall and muscle layer of the mesenteric arteries used in the present experiments were significantly thicker in the SHRSP preparations. 6. Calculation of the half relaxation time, based on the diffusion of Ca2+ across the blood vessel wall, suggested that the slower relaxation in preparations from SHRSP is due largely to the thicker muscle layer, although differences in Ca2+ sequestration by the smooth muscle cells may also be involved.

Animals↗
PubMed1990

Regulation of external work of concentric hypertrophied left ventricles in unanesthetized hypertensive dogs.

This study aimed to evaluate the change in external work and its control mechanism in the concentric hypertrophied heart induced by systemic hypertension. The calculated stroke work, myocardial contractility, afterload, and preload were examined in the baseline period (Control Stage, CS) and in the eighth week after the induction of perinephritic hypertension (Hypertensive Stage, HS) in unanesthetized dogs. These variables were examined with echocardiograms and high-fidelity left ventricular (LV) and ascending aortic pressures. Mean aortic pressure was significantly (p less than 0.05) elevated from 95 +/- 10 to 134 +/- 27 mmHg in HS. The ratio of end-diastolic wall thickness to radius significantly (p less than 0.05) increased in the HS. The calculated stroke work of the LV chamber was significantly (p less than 0.05) increased from 7022 +/- 1203 to 8860 +/- 1548 X 10(3) erg in HS while the stroke work normalized for wall thickness by calculating the wall stress was not altered (3069 +/- 1086 v.s. 2989 +/- 866 erg; CS v.s. HS) with no significant change in heart rate in HS. In the HS, the end-systolic wall stress (afterload) and the slope of end-systolic wall stress-dimension relationship (myocardial contractility) were unchanged while the end-diastolic wall stress (preload) slightly reduced. These results suggest that, in the concentric hypertrophied left ventricle induced by systemic hypertension, the LV myocardial external work is normal, whereas the LV chamber external work increases.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Field emission scanning electron microscopic study on the noninfarcted myocardium after myocardial infarction.

Intracellular membranous ultrastructural changes in the noninfarcted myocardium of the left ventricle were studied by examining experimental myocardial infarction in rats with a field emission scanning electron microscope. The left coronary artery was ligated at its origin for 7 days. The resulting infarcts comprised approximately 40% of the total area of the left ventricles. In a light microscopic study, the transverse diameter of myocytes had increased to 17.1 +/- 2.9 microns in the noninfarcted myocardium, compared to 14.1 +/- 3.1 microns in the myocardium of sham-operated rats (p less than 0.01). For the scanning electron microscopic study, the specimens were processed according to the Osmium-DMSO-Osmium method. Marked morphological changes of intracellular membranous structures were found in the noninfarcted myocardium, especially in the lacelike network of sarcoplasmic reticulum which occasionally formed large flattened cisternae, and in the marked proliferation of surface caveolae. It is speculated that these early ultrastructural changes in the noninfarcted myocardium reflect an adaptation of microorganellae in the failing hearts of the rats.

Animals↗
PubMed1990

Effects of E-1020, a new cyclic AMP-specific phosphodiesterase inhibitor, on cyclic AMP and cytosolic free calcium of cultured vascular smooth muscle cells.

The purpose of this study is to clarify the pharmacological effects of E-1020 a new cAMP-specific phosphodiesterase (PDE) inhibitor, on cAMP or cytosolic free calcium (Ca) of cultured vascular smooth muscle cells (VSMC). VSMC were separated from the thoracic aorta of 2- to 3-month-old Wistar Kyoto rats (WKY). cAMP was measured by using the 125I-cAMP radioimmunoassay kit. The cytosolic free Ca of VSMC was measured by using the fluorescence Ca indicator, Fura-2/acetoxymethyl ester (Fura-2/AM). As a result, E-1020 increased the cAMP of VSMC in a dose-dependent manner, and about two fold increase in cAMP was observed by 10(-4) M E-1020. E-1020 decreased the cytosolic free concentration of Ca in a dose-dependent manner, and a significant decrease in cytosolic free Ca was observed by greater than 10(-6) M E-1020. These effects of E-1020 on cAMP and cytosolic free Ca were enhanced in the presence of low concentration (10(-8) M) of DL-noradrenaline. That is, a more prominent decrease in cytosolic free Ca than that of E-1020 alone was observed. Our results show that E-1020 decreases cytosolic free Ca of VSMC in parallel with increase in cAMP, and thereby suggest a potential vasodilating activity in vivo.

Animals↗
PubMed1990

Three-dimensional observation on sarcoplasmic reticulum and caveolae in myocardium of spontaneously hypertensive rats.

Three-dimensional observation of intracellular membranous structures in myocardium was carried out in spontaneously hypertensive rats (SHR; a model of hypertrophied myocardium) under a scanning electron microscope (SEM) and compared with those of age- and sex-matched normotensive Wistar-Kyoto rats (WKY). There was no apparent difference in the ultrastructures of the myocardium between 5-week-old SHR (before the onset of hypertension but with mild cardiac hypertrophy) and age- and sex-matched control rats. Ten-week-old SHR in an early stage of hypertension with significant cardiac hypertrophy, showed a significant increase in the number of caveolae compared with those of 10-week-old WKY, and numerous abnormal caveolae aggregates connected by filamentous structures. Moreover the density of the network of sarcoplasmic reticulum (SR) was also increased, and some SR had a giant, squamous appearance. Accumulation of mitochondria with dense cristae was also observed in 10-week-old SHR. In 20-week-old SHR with established hypertension and cardiac hypertrophy, the caveolae and SR observed in 10-week-old SHR were no longer present, but caveolae were distributed in bands with variable width, parallel to the long axis of the myocardium. A wavy arrangement of mitochondria, fragmentation and stacks of mitochondrial cristae were observed in 20-week-old SHR. The changes of caveolae and giant squamous SR in cardiac hypertrophy observed in the present study have never been reported in previous studies. Our results suggest that the changes in caveolae, SR and mitochondria observed in SHR may be important morphological signs during development of cardiac hypertrophy in SHR.

Animals↗
PubMed1989

Ruptured aneurysm of the sinus of Valsalva with single coronary artery.

This paper will report the case of a patient with an aneurysm of Valsalva's sinus accompanied by single coronary artery (the presence of only a single ostium of the coronary arteries), who survived for 14 years, under conservative treatment, after a rupture of the aneurysm. In this patient the aneurysm of Valsalva's sinus ruptured from the right coronary sinus into the right ventricular outflow tract. The single coronary artery originated from the left coronary sinus, and the right coronary artery branched from the left main trunk and ran dorsally to the aorta. No case of ruptured aneurysm of Valsalva's sinus accompanied by a single coronary artery has been reported in the literature. After 14 years of conservative treatment, the patient was surgically treated by direct suture of the ruptured aneurysm and by aortic valve replacement. The postoperative course was uneventful.

Aortic Aneurysm↗