Biomedical subjects

Y Matsukura

Publications and source records attributed to Y Matsukura.

At least 19 recordsLinked to original sources

PubMed1999

Effects of exercise training on the heart rate variability and QT dispersion of patients with acute myocardial infarction.

Heart rate variability (HRV) reflects the autonomic tone of the heart, and QT dispersion reflects the regional inhomogeneity of ventricular repolarization. The purpose of the present study was to determine the effects of early exercise training on HRV and QT dispersion in patients with acute myocardial infarction (AMI). Forty patients (mean age: 59 years) with AMI were randomized to training rehabilitation (group Tr, n=20) or conventional rehabilitation (group C, n=20). Two weeks after AMI, group Tr underwent 10 min of exercise using a bicycle ergometer (80% of anaerobic threshold) twice a day. At the end of the second and fourth weeks, 12-lead and 24-h Holter ECGs were recorded. QT intervals were measured and corrected using Bazett's formula (QTc), and QTc dispersion (QTcd) was defined as the difference between maximum and minimum QTc. HRV was accessed by the high-frequency component (HF: 0.15-0.40 Hz) of the HRV power spectrum (parasympathetic activity) and the ratio of low frequency (0.04-0.15 Hz) to HF (L/H ratio: sympathetic activity). In group Tr, HF increased (82.5 to 131.1 ms2), the L/H ratio decreased (3.9 to 2.6), and QTcd decreased (77.2 to 57.2 ms). In group C, none of the indices changed. It was concluded that early exercise training improves sympathovagal balance and decreases QTcd, and may reduce the arrhythmogenic substrate following AMI.

Aged↗

PubMed1998

[Assessment of autonomic nervous activity before the onset of paroxysmal atrial fibrillation].

Autonomic nervous activity is involved in the onset of paroxysmal atrial fibrillation, but it is not clear how the sympathetic and parasympathetic nervous systems interact before the onset of atrial fibrillation. Twelve lone atrial fibrillation patients and 10 healthy volunteers were studied using 24-hour Holter electrocardiography monitoring. A total of 17 episodes were analyzed. Autonomic nervous activity was assessed based on the high frequency power (HF) spectrum (HF represents parasympathetic nervous activity) and the ratio to the low frequency power (LF) spectrum (L/H represents sympathetic nervous activity) of heart rate variability during sinus rhythm, and the 24-hour averaged autonomic indices were compared between atrial fibrillation patients and healthy volunteers. Comparative data were obtained 30, 20, 10, and 2 min before the onset of atrial fibrillation for each episode. There were no significant differences in the HF and L/H ratio between the patients and healthy volunteers. There were no significant differences in the HF values before the onset of paroxysmal atrial fibrillation, but the L/H ratio before the onset of atrial fibrillation at 30, 20 and 10 min was 1.03 +/- 0.42, 0.95 +/- 0.50, and 1.32 +/- 0.46, respectively, and just before the episode was 1.73 +/- 0.73, so the Spearman's rank correlation coefficient was 0.43. Basal autonomic nervous activity in patients with paroxysmal atrial fibrillation showed no changes compared with healthy volunteers. Sympathetic nervous activity increased progressively from about 30 min before the onset of atrial fibrillation, but parasympathetic nervous activity showed no significant changes. Therefore, a transient augmentation of sympathetic tone may be important in the onset of atrial fibrillation.

Adult↗

PubMed1998

Upregulation of CD44 in the inflamed mouse air pouch injected with synthetic lipid A.

OBJECTIVE: To investigate aspects of the inflammatory process of the mouse subcutaneous air pouch -- a facsimile synovial cavity -- induced by injection of lipid A, and to determine the expression and upregulation of CD44 in the lining cell layer of the inflamed air pouch. METHODS: Histological changes of inner walls in the mouse air pouch were evaluated 1, 3, and 7 days after injection of lipid A. RESULTS: Polymorphonuclear cell infiltration in the lining layer reached the maximum one day after injection of 10 microg of lipid A (10/10 mice in Grade 3; p < 0.01), while mononuclear cell infiltration and lining cell hyperplasia reached the maximum 3 days after injection (5/10 mice in Grade 2; 5/10 in Grade 3; p < 0.05; 39+/-11 layers, p < 0.05, respectively). The number of cell depth of CD44 positive lining layers and interleukin 1alpha (IL-1alpha) positive lining layers reached the maximum 3 days after injection (39+/-7 layers, p < 0.01; 35+/-12 layers, p < 0.05, respectively). CONCLUSION: These findings suggest that CD44 may have some connection with the proinflammatory cytokine IL-1alpha and induce inflammatory responses in the air pouch injected with lipid A.

Animals↗

PubMed1997

Heart rate variability and ventricular arrhythmia in clinically stable patients with hypertrophic cardiomyopathy.

To investigate whether autonomic nervous dysfunction exists and to determine the relationship between autonomic nervous activity and ventricular arrhythmias in clinically stable patients with hypertrophic cardiomyopathy (HCM), we studied heart rate variability (HRV) in 21 patients with HCM and 10 age-matched healthy control subjects. Patients were divided into 2 groups: HCM I (14 patients without nonsustained ventricular tachycardia, defined as 3 or more consecutive ventricular premature beats) and HCM II (7 patients with nonsustained ventricular tachycardia). HRV was measured on 24-h ECG monitorings using both nonspectral and spectral methods (fast Fourier transform, FFT). We assessed autonomic nervous activity based on high-frequency (HF; 0.15-0.40 Hz, an index of parasympathetic nervous activity) and the low- to high-frequency power ratio (L/H ratio; an index of sympathetic nervous activity) during daytime and night-time separately. There were no significant differences in any index of HRV between the HCM I and control groups. HF in the HCM II group was significantly lower than that of both the HCM I and control groups during the day and at night, whereas the L/H ratio at night-time was significantly higher in the HCM II group than in the HCM I and control groups. These data demonstrate that, in clinically stable HCM patients without nonsustained ventricular tachycardia, autonomic nervous activity was not different to that of healthy control subjects, whereas in HCM patients with nonsustained ventricular tachycardia, parasympathetic nervous activity was reduced throughout the 24-h period, and sympathetic nervous activity at night was increased compared with healthy control subjects. Thus, HCM patients with nonsustained ventricular tachycardia have to be treated even if they do not exhibit significant clinical manifestation.

Adult↗

PubMed1997

Decreased pulmonary arterial endothelium-dependent relaxation in heartworm-infected dogs with pulmonary hypertension.

OBJECTIVE: To investigate the contractility of pulmonary arterial smooth muscle and the relation between pulmonary hypertension and endothelium-derived relaxing factor in canine heartworm disease. ANIMALS: 18 noninfected control and 9 heartworm-infected dogs. PROCEDURE: Mean pulmonary arterial blood pressure was measured in vivo, and tension of pulmonary arterial strips was measured by use of the isometric tension method. RESULTS: After phenylephrine (10(-5)M)-induced contraction of the pulmonary vascular smooth muscle, carbamylcholine chloride (CCh, 10(-6)M) caused more relaxation of the vascular smooth muscle of noninfected, dogs than that of heartworm-infected dogs. Furthermore, the degree of CCh-induced relaxation was inversely correlated with mean pulmonary arterial blood pressure in the noninfected and the heartworm-infected dogs. The CCh-induced relaxation was inhibited by pretreatment with NG-nitro-L-arginine methyl ester hydrochloride (10(-5)M), and in reversed dose-dependent manner by L-arginine (10(-4) to 3 x 10(-2)M). Sodium nitroprusside (10(-8) to 10(-5)M) caused a dose-dependent relaxation in all vessels, and there was no significant difference in the relaxation responses in both groups except at 10(-7)M for vessels with intact endothelium from noninfected dogs. CONCLUSION: The depression of endothelium-dependent relaxation is correlated with the pulmonary arterial blood pressure in heartworm-infected dogs, suggesting that the decrease is one of the essential factors for the genesis of pulmonary hypertension in canine filariasis.

Animals↗

PubMed1997

[Effects of physical training on autonomic nerve activity in patients with acute myocardial infarction].

The effects of early physical training on heart rate variability and autonomic nerve activity in acute myocardial infarction were studied in 20 patients (men, mean age 57 +/- 11 years) successfully treated by direct coronary angioplasty. Patients were randomly divided into the physical training group (training group: 10 patients) and conventional rehabilitation group (non-training group: 10 patients). Exercise tolerance (VO2 peak and anaerobic threshold: AT), heart rate variability indices, serum levels of catecholamines, and 24-hour urinary excretion of catecholamines were measured on the 14th and 28th days. The conventional cardiac rehabilitation program was followed by each group, and the training group patients were also instructed to follow a training program using the bicycle ergometer (80% AT, 10 min, 2 times a day) for 2 weeks from the 15th day. Autonomic nerve activity was assessed by non-spectral (24-hour averaged normal RR intervals: mean NN, standard deviation of normal RR intervals over 24 hours: SDNN and standard deviation of the mean RR intervals for each 5 min periods over 24 hours: SDANN) and spectral [high frequency power (HF) 0.15-0.40 Hz; represents parasympathetic activity, and the low/high frequency power (L/H ratio); represents sympathetic activity] indices of heart rate variability. There were no cardiac events during physical training. Comparison of the 14th and 28th day in the training group showed that the VO2 peak and VO2 AT significantly increased, SDNN and SDANN significantly increased, HF (82.5 +/- 56.2 to 131.1 +/- 99.8 msec2) increased and the L/H ratio (3.9 +/- 2.2 to 2.6 +/- 1.3) decreased significantly during the night-time, and serum noradrenalin concentration (0.47 +/- 0.11 to 0.35 +/- 0.13 ng/ml) and urinary noradrenalin excretion (195.6 +/- 130.7 to 139.6 +/- 73.3 micrograms/day) significantly decreased. In contrast, the non-training group showed no significant changes. These results suggest early physical training may be safe and improves the autonomic nerve balance and exercise tolerance in patients with acute myocardial infarction.

Aged↗

PubMed1996

Longitudinal distribution of pulmonary vascular compliance in dogs.

The longitudinal distribution of pulmonary vascular compliance was evaluated in isolated canine lung lobes using arterial-(AO), venous-(VO), and double-occlusion (DO) techniques. Total vascular compliance (Ctau) was separated into pulmonary arterial (Ca) and venous compliance (Cv) in lumped model of pulmonary circulation. Under constant pulmonary venous pressure (Pv) at 5 mmHg, blood inflow to the lobe (Q) was gradually increased by changing pulmonary arterial pressure (Pa) from 10 to 22 mmHg at 4 mmHg ranges. Changes in vascular blood volume (deltaV) with each increment in Q were determined by decreased reservoir blood volume of perfusion system. DO was performed at each level of Q and allowing all vascular pressures to equilibrate at the same static pressure (Ps), which was equal to the compliance-weighted average pressure in the circulation. Ctau was obtained from the slope of the relationship between Ps and deltaV. When Pa and Pv were 14 and 5 mmHg, AO, VO, and DO were performed to measure pressures at Ca (Pca) and Cv (Pcv) and Ps. The arterial-to-venous compliance ratio (Ca/Cv) was evaluated using Pca, Pcv, and Ps measurements. Ctau was 0.113 +/- 0.012 ml/kg/mmHg. Ca/Cv was 0.30. Ca and Cv were 0.026 +/- 0.013 and 0.087 +/- 0.007 ml/kg/mmHg, respectively. These data demonstrated the usefulness of AO, VO, and DO techniques in evaluating the longitudinal distribution of compliance in canine pulmonary vasculature.

Animals↗

PubMed1996

[A case study of immunohistochemical findings of rheumatic pseudocystic lesions in the femoral lateral condyle and tibial plateau--the comparison with synovial lesions].

Rheumatoid pseudocysts of which pathogenesis are not well known, are commonly observed in the major joints of the body, especially knees in rheumatoid patients. This report investigated the pseudocysts in the knee of a rheumatoid patient radiologically and immunohistochemically. A sixty-three-year-old woman with rheumatoid arthritis who had pseudocysts in the femoral lateral condyle and tibial plateau was hospitalized to have the lesions surgically removed. The MRI findings showed a connection between the pseudocysts and the joint cavity. A window of 1 x 1 cm2 was made at the tibial anterior cortex and the contents of the pseudocyst were resected and hydroxyapatite granules were inserted into the lesion after the removal of the pseudocyst tissue. In the histological findings, the specimen from the tibial pseudocyst revealed fibrous connective tissue with a few inflammatory cells, while the synovial specimen revealed the fibrous tissue with intense inflammatory cells infiltration forming lymphoid follicules. In immunohistochemical findings, both specimens showed positive with anti-HLA class I, anti-HLA DR, anti-CD44 and anti-HSP70 antibodies. The pathological findings of the pseudocystic lesion were similar to those of synovia, and it was considered that the synovia had invaded into the bone and formed the pseudocystic lesion. The MRI findings also support this hypothesis. The pseudocystic lesion was surrounded by bone and it was isolated from cytokain-rich joint effusion. This isolation from rheumatic joint effusion may explain the weaker inflammation of the pseudocystic lesion than that of synovia.

Arthritis, Rheumatoid↗

PubMed1995

The effect of indomethacin on liver blood flow and oxygen supply-uptake relationship in the dog.

The effects of indomethacin on liver blood flow and oxygen supply-uptake relationship were investigated using a right heart bypass technique. Portal venous blood flow was decreased by the mesenteric vascular effects of indomethacin, which produce intense mesenteric vasoconstriction. Hepatic arterial blood flow was increased and therefore, total liver blood flow was not significantly changed after indomethacin administration. Portal venous oxygen delivery was significantly decreased by reductions in both portal venous blood flow and portal venous oxygen content. Total liver oxygen delivery, however, was not changed after indomethacin administration. This response was caused by a large increase in hepatic arterial oxygen delivery. Liver oxygen uptake and liver oxygen extraction ratio were not changed after indomethacin administration. We conclude, therefore, that total liver blood flow and oxygen delivery were well maintained, even if the mesenteric vascular effects of indomethacin decreased both portal venous blood flow and portal venous oxygen delivery.

Animals↗

PubMed1995

The effects of dopamine and dobutamine on liver oxygen supply-uptake relationship in the dog.

The effects of dopamine and dobutamine in various doses on liver oxygen supply-uptake relationship were studied in 12 mongrel dogs. Dopamine 3 and 7 micrograms/kg/min infusion rates and dobutamine 5 micrograms/kg/min infusion rate did not produce any changes in total liver oxygen delivery. On the contrary, total liver oxygen delivery was increased at the 15 micrograms/kg/min dopamine in fusion rate and dobutamine 10 and 15 micrograms/kg/min infusion rates. The ratio of total liver oxygen delivery to the systemic oxygen delivery was increased at the 15 micrograms/kg/min dopamine infusion rate. Liver oxygen extraction ratio was decreased at the 15 micrograms/kg/min dopamine infusion rate and at the same rate of dobutamine. These decreases were due to the increases in oxygen delivery while both oxygen uptakes were avariant from control levels. The results of this study demonstrated that high dose of dopamine (15 micrograms/kg/min) and medium and high doses of dobutamine (10 and 15 micrograms/kg/min) should be useful to increase the liver oxygen delivery. However, these increases in liver oxygen delivery during dopamine and dobutamine infusion were not associated with an improvement in liver oxygen metabolism, since liver oxygen uptake was not changed.

Animals↗

PubMed1995

The selective effects of dopamine and dobutamine on liver circulation in the dog.

The selective effects od dopamine and dobutamine in various doses on liver circulation were studied in 12 mongrel dogs. Dopamine increased portal flow but decreased hepatic arterial flow markedly as infusion rate of dopamine increased. Dopamine 3 micrograms/kg/min infusion rate produced vasodilation in mesenteric vascular bed and the portal flow ratio to cardiac output was significantly increased. Dobutamine increased both portal and hepatic arterial flows at the 5 and 10 micrograms/kg/min dobutamine infusion rates, and decreased hepatic arterial flow at the 15 micrograms/kg/min dobutamine infusion rate. Both dopamine and dobutamine increased total liver flows, however, total liver flow ratio to cardiac output was not increased. Pressure gradient of portal system was not changed during dopamine and dobutamine infusion, since both portal venous pressure and hepatic venous pressure were avariant from control values. These findings suggest that congestive hyperemia was not occurred in intrahepatic portal vascular system when portal flows were increased during dopamine and dobutamine infusion. The results of this study demonstrate that both dopamine and dobutamine did not produce selective increases in total liver blood flow. In addition, both agents should be safe to use to the normal liver patient; total liver blood flow did not decrease and intrahepatic congestive hyperemia was not occurred when portal flow was increased.

Animals↗

PubMed1995

Effect of food on liver circulation in conscious dog.

Hepatic hemodynamics and the liver oxygen supply-uptake relationship, in response to eating, were investigated in a chronically catheterized conscious dog method. Portal venous pressure was significantly increased after eating, however was within the normal range reported previously. Hepatic venous pressure correlated well with portal venous pressure throughout the experiment, therefore, the pressure gradient of the portal system was unchanged. Hepatic venous oxygen content, correlated well with liver oxygen extraction, was unchanged after eating. Therefore, it is possible to assume that liver oxygen supply-uptake relationship is well maintained during digestion of food.

Animals↗

PubMed1994

Analysis of longitudinal distribution of pulmonary vascular resistance by use of a five element lumped model.

To analyze longitudinal distribution of pulmonary vascular resistance, we proposed a five element lumped model which partitioned pulmonary circulation into pulmonary arterial, middle and pulmonary venous segment. The validity and anatomical correlation of the model were tested in an isolated, perfused, canine lung lobe preparation with inflow/outflow occlusion techniques. With arterial occlusion, pulmonary arterial pressure fell rapidly and then exponentially. With venous occlusion, pulmonary venous pressure rose suddenly and then exponentially. Theoretical pressure profiles produced by computer simulation of the model well approximated the general characteristics of the experimental traces. Serotonin increased the pressure gradient across the pulmonary arterial segment (delta Pa), whereas histamine increased the gradient across the pulmonary venous segment (delta Pv). Neither drug altered the gradient across the middle segment (delta Pm). The results suggest that the lumped model is a useful concept to understand the longitudinal distribution of pulmonary vascular resistance, and that delta Pa, delta Pm and delta Pv reflect the resistance distribution of anatomical pulmonary arteries, alveolar vessels and pulmonary veins, respectively.

Animals↗

PubMed1994

Cardiovascular effects of dibutyryl cyclic AMP and milrinone under right heart bypass in anesthetized dogs.

To compare the cardiovascular effects of dibutyryl cyclic AMP (DBcAMP) and milrinone, we used the right heart bypass method in intact anesthetized dogs. The preload of the left ventricle was maintained constant throughout the experiment. Therefore, the effects of DBcAMP and milrinone on cardiac contractility and afterload of the left ventricle were investigated respectively without preload influence. DBcAMP and milrinone exhibited marked positive chronotropic-, positive inotropic-, vasodilative- and diuretic-activity. DBcAMP expressed these effects gradually and continuously, whereas milrinone expressed its pharmacological actions rapidly, but for a short duration of time. Both the afterload-reducing and the cardiac contractile force-enhancing activities of DBcAMP were longer lasting than those of milrinone. Mean arterial pressure was not altered by DBcAMP infusion, whereas it was increased significantly (p < 0.05) by milrinone infusion. The results of this study suggested that DBcAMP appeared to be indicated when there is a need to increase cardiac output by reducing afterload and increasing cardiac contractile force gradually and continuously. On the other hand, milrinone would seem to be indicated when the goal is to raise blood pressure rapidly and to increase cardiac output simultaneously.

Animals↗

PubMed1976

Electron microscopic observations on the H antigen sites of human erythrocytes using ferritin antibody conjugates.

Using immunoelectron microscopy, the distribution of the H antigen sites on human erythrocytes was observed in 40 samples of adult, newborn and fetal blood of different ABO phenotypes. The attached ferritin particles indicating the H antigen sites conspicuously varied in number from cell to cell in every specimen. The number of H antigen sites per single red cell was estimated on an average for each sample as follows: O, 3 X 10(5); B, 2 X 10(5); A1, 1.5 X 10(5); A1B, 10(5); A2B, 1.5 X 10(5); Ax, 2.5 X 10(5); AxB, 10(5); Bm, 4 X 10(5); Bw(leukemia), 4 X 10(5); O(newborn), 2.5 X 10(5); B(newborn), 3 X 10(5); A1(newborn), 1.5 X 10(5); A1B(newborn), 2 X 10(5); A1B(fetus), 10(5). The cells in each sample were divided into six cell-populatons according to the number of H antigen sites present. The ratios of distribution of such cell populations are compared for all samples.

ABO Blood-Group System↗

PubMed1976

Ferritin as a surface marker for immunoscanning electron microscopy. observation of individual ferritin particles on erythrocytes.

This paper comprises a part of our study to examine whether ferritin can be used as an immunological surface marker for high resolution scanning electron microscopy. In the first part of the study individual ferritin particles in a sample of purified ferritin were demonstrated as spheres with a diameter of about 170 A by use of fixation by glutaraldehyde and thin coating by ion sputtering. In the second part of this study, ferritin particles as indicating the antigen sites of blood group A were also recognized on the erythrocytes by the same techniques as in the first part. Ferritin deposition differed in amount among the erythrocytes, but without regard to the shape of the cells. On the individual erythrocytes, heavier depositions tended to occur in the concavity of the cell. In conclusion, ferritin is useful as a surface marker in immunoscanning electron microscopy. It has the benefit, in comparison with the other markers hitherto reported, of allowing us to observe the fine features of the cell surface under immunological reaction.

ABO Blood-Group System↗

PubMed1976

Alpha-galactosyltransferase activity in the serum of frogs (Rana catesbeiana).

Human blood group 0 cells were converted into B-active cells by incubation with uridine diphosphate D-galactose and unfractionated serum from bull frog (Rana catesbeiana). Under these conditions, "Bombay" (Oh) type red cells were not converted, and group 0 foetal cells possessing a few H antigenic sites were only weakly converted into B-active cells. In addition, the agglutination titer of the converted cells with anti-H serum decreased. These results therefore indicate that the conversion depends upon the presence of H-substance on the red cells. It was concluded from the results of this investigation that the blood group B specific alpha-galactosyltransferase was present in the serum of Rana catesbeiana as well as in the human group B serum.

ABO Blood-Group System↗

PubMed1976

On the blood group B gene-specified alpha-galactosyltransferase in the serum of the Japanese tortoise (Clemmys japonica).

Human blood group O cells were converted into B-active cells by incubation at either 4 degrees or 37 degrees with uridine diphosphate D-galactose and unfractionated serum from the Japanese tortoise (Clemmys japonica). The specificity of the converted cells was tested by their reactions with human anti-B, anti-A and rabbit anti-B sera. Under the conditions used, Bombay (Oh) type cells were not converted, and group-O foetal cells possessing a few H antigenic sites were only weakly converted into B-active cells. In addition, the agglutination titre of the converted cells with eel anti-H serum decreased. These results therefore indicate that the conversion depends upon the preference of H-substance on the red cells. The alpha-galactosyltransferase in tortoise serum thus resembles the transferase in human group-B serum and these results suggest that the mechanism of biosynthesis of blood group B substance in the tortoise is similar to that in humans.

ABO Blood-Group System↗