The supernormal phase in muscular contraction.
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Journal Article↗
Biomedical subjects
T Kamada
Publications and source records attributed to T Kamada.
Immunohistochemical distribution of glucagon, substance P and vasoactive intestinal polypeptide in hepatic vasculature of the rat.
The distribution of immunoreactive glucagon, substance P (SP) and vasoactive intestinal polypeptide (VIP)-like structures was investigated in the rat liver, with special reference to the hepatic vasculature by means of the indirect immunofluorescence method. Immunoreactive structures of glucagon were seen in the walls of the portal vein, hepatic artery and hepatic vein, but not in the central vein. Immunoreactive glucagon was localized in the smooth muscle cells of these blood vessels. SP and VIP-like immunoreactive (SPI and VIPI) structures were seen in the neuronal elements. In the porta hepatis, thick, compact SPI and VIPI fibers, which were dissociated from their fiber bundles, reached the tunica adventitia where they were distributed. No SPI and VIPI structures were seen in the tunica media or the tunica interna. No SPI- and VIPI-containing cell bodies could be detected in the liver. These observations suggest that these peptides may have an important role in the neural regulation of hepatic hemodynamics.
Animals↗
Hepatic hemodynamics and oxygen consumption in alcoholic fatty liver assessed by organ-reflectance spectrophotometry and the hydrogen clearance method.
Hepatic blood flow and estimated hepatic oxygen consumption were studied in rats treated chronically with ethanol by organ-reflectance spectrophotometry and the hydrogen clearance method. In the withdrawal state from ethanol, the concentration of hemoglobin in the hepatic tissue (delta Er569-650), the estimated hepatic oxygen consumption (estimated VO2) and the regional liver blood flow decreased significantly in rats treated chronically with ethanol in comparison with their controls. On the other hand, there was no significant difference in the estimated oxygen saturation of the hepatic blood hemoglobin (estimated SO2) between both groups. That is, an increase in oxygen extraction, which was exhibited by a decrease in the estimated SO2, did not occur in rats treated chronically with ethanol in spite of a decrease in blood supply. Thus, in the withdrawal state from ethanol, both oxygen delivery to the liver and oxygen utilization in the liver were disturbed at the stage of alcoholic fatty liver.
Animals↗
Hepatic hemodynamics in alcoholic liver injuries assessed by reflectance spectrophotometry.
We have investigated the hepatic hemodynamics by reflectance spectrophotometry in patients with alcoholic liver disease. The analysis of 32 cases has shown that the estimated regional hepatic tissue blood hemoglobin concentration, expressed as a difference in absorbance between 569 and 650 nm (delta Er569-650), decreased significantly with progress of fibrosis in the liver, suggesting the relative compression of the vascular compartment due to the progress of alcoholic liver disease. The estimated hepatic oxygen consumption also decreased with progress of fibrosis in the liver. The estimated hepatic oxygen consumption correlated positively with prothrombin time and serum albumin level, and negatively with the fifteen minute retention rate of indocyanine green. Thus, it is concluded that the imbalance between supply and utilization of oxygen in the liver may have an important role in the progress of alcoholic liver disease.
Adult↗
Effect of alcohol ingestion on portal venous blood flow in healthy volunteers: comparison between the subjects with and without ALDH I isozyme.
Effect of alcohol ingestion (25 g ethanol) on portal venous blood flow was investigated in healthy subjects using an ultrasonic pulsed doppler method. It was found that; (1) portal blood flow increased by 24% at 30 minutes and returned to the basal level at 60 minutes after alcohol ingestion; (2) there was no significant difference in the effect of alcohol ingestion on portal blood flow between the subjects with and without ALDH I isozyme; (3) blood ethanol levels correlated with portal blood flow at 30 minutes after alcohol ingestion, while this correlation was not observed at 60 minutes thereafter; and (4) blood acetaldehyde levels did not correlate with portal blood flow either at 30 minutes or at 60 minutes following alcohol ingestion. In conclusion, the portal blood flow increases following alcohol ingestion which is not associated with the increase in the blood acetaldehyde level.
Acetaldehyde↗
Chemiluminescence and superoxide dismutase in the plasma in patients with alcoholic and non-alcoholic liver injuries.
The chemiluminescence level and superoxide dismutase (SOD) activity were determined in the plasma of patients with alcoholic and non-alcoholic liver injuries. Chemiluminescence level was significantly higher in alcoholics than in non-alcoholics. It increased significantly in patients with fatty livers and had a tendency to increase with the progression of alcoholic liver injury from a fatty liver to liver cirrhosis. Mn-SOD activity was elevated in patients with alcoholic liver injuries. Furthermore, there was a positive correlation between the levels of plasma chemiluminescence and plasma Mn-SOD activity. The increases in chemiluminescence and Mn-SOD activity suggests that the generation of a large amount of activated oxygen is associated with the pathogenesis and progression of alcoholic liver injury in humans.
Adult↗
Recent progress in the treatment of diabetic nephropathy: importance of strict glycemic control on the regression of diabetic nephropathy.
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Biomarkers↗
Subclinical exocrine pancreatic derangement in human diabetic patients evaluated from pure pancreatic juice.
To elucidate the mechanism responsible for histological derangement of pancreas in diabetic patients, pure pancreatic juice (PPJ) aspirated directly from pancreatic duct was analyzed before and after strict glycemic control on poorly controlled diabetic patients without clinical exocrine pancreatic dysfunction. PPJ obtained from 18 diabetics showed a significantly decreased amylase activity compared with ten healthy subjects (109 +/- 4 versus 168 +/- 9 U/mg protein, p < 0.005) in spite of negligible changes in lipase activity, protein concentration, bicarbonate concentration, and its volume. PPJ showed higher concentrations of prostanoids in diabetic patients than in healthy subjects (TXB2, 259 +/- 48 versus 118 +/- 30 pg/mL, p < 0.05; 6-keto-PGF1 alpha, 52.6 +/- 11.5 versus 38.5 +/- 7.5 pg/mL, p > 0.05). Ratio of 6-keto-PGF1 alpha/TXB2 of PPJ in diabetic patients was significantly lower than in healthy subjects (0.195 +/- 0.016 versus 0.422 +/- 0.041, p < 0.005). After strict glycemic control for 1-3 months on nine of 18 diabetic patients, amylase activity of PPJ was significantly higher than that before the control (112 +/- 4 versus 128 +/- 7 U/mg protein, p < 0.01), but still significantly lower than that of healthy subjects (p < 0.005). Lipase activity showed no significant difference between before and after the control. TXB2 and 6-keto-PGF1 alpha concentrations were decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
6-Ketoprostaglandin F1 alpha↗
Functional imaging for the analysis of the mucosal blood hemoglobin distribution using electronic endoscopy.
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Animals↗
Effects of low-dose simvastatin therapy on serum lipid levels in patients with moderate hypercholesterolemia: a 12-month study. The Simvastatin Study Group.
The aim of this study was to investigate the safety and long-term effects on serum lipid levels of low-dose simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, in Japanese patients with moderate primary hypercholesterolemia. We assigned 201 patients (68 men and 133 women; mean +/- SD age, 61.3 +/- 10.2 years) with serum total cholesterol levels > or = 220 mg/dL to receive simvastatin 5 mg each evening; the treatment period was 1 year. Serum total cholesterol, triglycerides, and low-density lipoprotein (LDL) cholesterol levels decreased significantly in response to simvastatin therapy, and the changes were maintained throughout the treatment period. Mean total cholesterol decreased from 269.9 +/- 35.4 mg/dL to 215.2 +/- 34.5 mg/dL (20.3%), triglycerides decreased from 183.0 +/- 110.2 mg/dL to 155.5 +/- 88.5 mg/dL (15.0%), and LDL cholesterol decreased from 180.0 +/- 33.1 mg/dL to 130.1 +/- 35.1 mg/dL (27.7%). Total cholesterol, triglycerides, and LDL cholesterol tended to decline when the pretreatment values were higher; the critical values and the bidirectional changes of the serum lipid levels were 188.1, 109.5, and 91.6 mg/dL, respectively. Although the serum level of high-density lipoprotein cholesterol did not change significantly, it tended to increase more when the pretreatment values were lower; the "critical value" was 70 mg/dL. Nine patients experienced mild adverse events, but none discontinued simvastatin during the 12-month treatment period. We found that low-dose simvastatin therapy is effective in achieving long-term decreases in serum lipid levels and is well tolerated by patients with moderate hypercholesterolemia. Simvastatin therapy may result in normalization of serum lipid levels.
Adult↗
Transthoracic Doppler echocardiographic measurements of pulmonary venous flow velocity patterns: comparison with transesophageal measurements.
Recently, we and other groups showed that analysis of transthoracic pulmonary venous flow velocity patterns is useful in the estimation of left ventricular diastolic function and left atrial pressure; however, it is unclear whether transthoracic tracings, in contrast to transesophageal tracings, provide reliable quantitation of the abnormal pulmonary venous flow characteristics in patients with and without cardiac disorders. This study was attempted to validate transthoracic pulmonary venous flow measurements by comparing them with transesophageal measurements in eight normal volunteers and 17 patients with a variety of cardiac disorders. Transesophageal and transthoracic measurements of peak diastolic forward flow velocity, the ratio of peak systolic/diastolic forward flow velocities, and the peak reversal flow velocity at atrial contraction sampled in the right upper pulmonary vein showed good correspondence to each other. The flow velocities were higher in the right upper pulmonary vein than in the left upper pulmonary vein. Narrower spectral flow velocity patterns with higher velocities were obtained 1 to 2 cm distal to the orifice in the pulmonary vein than at the orifice. Thus transthoracic measurements of the pulmonary venous flow velocity pattern are feasible and accurate in patients and may be used to assess left ventricular function and hemodynamics as a substitute for transesophageal measurements.
Adult↗
Progressive intraventricular drop of early diastolic flow velocity reflects impaired active ventricular diastolic function in hypertensive heart disease: comparative study between early diastolic and atrial contraction phases.
Left ventricular (LV) diastolic function in the early diastolic phase includes both active and passive processes, but in the atrial contraction phase it includes only passive processes. To elucidate the relation between the intraventricular dispersion of the flow velocity in diastole and LV diastolic process, 31 normal volunteers and 12 patients with hypertensive heart disease were studied. In these subjects the flow velocity pattern at the mitral tip was recorded simultaneously with regional flow velocity patterns 1, 2, or 3 cm from the mitral tip toward the apex, respectively, with multigate pulsed Doppler echocardiography from the apical long-axis view with the guidance of Doppler color-flow imaging. Although the ratio of regional peak flow velocity/mitral peak flow velocity in the atrial contraction phase decreased from the mitral tip to the apex to the same degree in the normal volunteers and patients with hypertensive heart disease, there was a significant difference in the intraventricular dispersion of the early diastolic flow velocity between the two groups. These results suggest that the progressive intraventricular drop of the flow velocity in the early diastolic phase in patients with hypertensive heart disease may reflect the impairment of active rather than passive LV diastolic function.
Adult↗
Transthoracic Doppler assessment of pattern of left ventricular dysfunction in hypertensive heart disease: combined analysis of mitral and pulmonary venous flow velocity patterns.
Although mitral flow velocity pattern changes with the progression of left ventricular (LV) diastolic dysfunction, it lacks predictive value in individual patients because of pseudonormalization in the presence of congestive heart failure and many physiologic and pathologic contributors to the mitral flow velocity pattern. To determine whether analysis of pulmonary venous flow velocity patterns complements the information obtainable from the mitral flow velocity patterns in the evaluation of patterns of LV dysfunction of hypertensive heart disease in individual patients, the ratio of the peak early diastolic filling velocity/peak filling velocity at atrial contraction (E/A ratio) in the mitral flow velocity pattern and the ratio of the peak systolic forward flow velocity (S)/peak diastolic forward flow velocity (D) (S/D ratio) in the pulmonary venous flow velocity pattern by the transthoracic approach were determined in 107 hypertensive patients with and without congestive heart failure. Age-related normal values of the E/A and S/D ratios were determined in 61 normal subjects and used to judge the normality or abnormality of the patterns. Results of the study indicate that (1) although an increased mitral E/A ratio is strongly indicative of heart failure with normal LV systolic function, the mitral E/A ratio is frequently within the normal range in hypertensive patients with heart failure; (2) association of decreased pulmonary venous S/D ratios with a normal mitral flow velocity pattern indicates the presence of heart failure as a result of LV systolic dysfunction that is usually observed at the most advanced pattern of LV dysfunction; (3) mild LV diastolic dysfunction is likely to exist in patients with normal E/A ratios if the pulmonary venous S/D ratio is higher than normal value; (4) predictive accuracy in the detection of LV systolic and diastolic dysfunction would be improved if both mitral and pulmonary venous flow velocity patterns rather than the mitral flow velocity pattern alone were analyzed. In conclusion, analysis of pulmonary venous flow velocity recordings improves accuracy and reliability of the Doppler assessment of LV systolic and diastolic dysfunction, particularly in individual hypertensive patients with normal mitral flow velocity patterns.
Adult↗
Decreased and abnormal left ventricular filling in acute heart failure: role of pericardial constraint and its mechanism.
Pericardial constraining force is minimal in normal hearts; however, it is considered to be prominent in moderate to severe heart failure. Thus, effects of the pericardium on pulsed Doppler transmitral flow velocity pattern were examined in 17 dogs with acute left ventricular dysfunction. Left ventricular dysfunction with left ventricular end-diastolic pressure > or = 15 mm Hg was produced by injection of microspheres into the left coronary artery. Transmitral flow velocity pattern, left atrial and left ventricular diameters, and high-fidelity left atrial and left ventricular pressures were recorded before and after pericardiectomy. In five of the 17 dogs, mitral regurgitation with giant "v" wave of left atrial pressure occurred with reductions of left ventricular systolic pressure and peak rate of the left ventricular pressure fall (dP/dt) after pericardiectomy. In the other 12 dogs, peak early and late diastolic filling velocities increased with a decrease in left ventricular minimal pressure and increases in left arterial and left ventricular diameters and left atrial and left ventricular compliance after pericardiectomy. In these 12 dogs, left atrial to left ventricular crossover pressure, left ventricular end-diastolic pressure, and references for left ventricular relaxation did not change after pericardiectomy. Thus the release from pericardial constraining force in severe heart failure may increase chamber compliance of the left ventricle and left atrium and, in turn, increase peak early and late diastolic filling velocities through an increment in forward transmitral pressure gradient. Increased pericardial constraining force is a possible cause limiting left ventricular filling and hence cardiac output in heart failure.
Acute Disease↗
Peak early diastolic filling velocity may decrease with preload augmentation: effect of concomitant increase in the rate of left atrial pressure drop in early diastole.
Doppler-determined transmitral flow velocity pattern has been shown to depend on transmitral pressure gradient, and left atrial (LA) pressure has been considered to be important in determining transmitral pressure gradient in early diastole and peak early diastolic filling velocity (E). In recent studies in human beings, however, it was proved that E did not necessarily change with LA pressure. This may be because concomitant changes in other factors masked the effect of LA pressure. To investigate the relation between transmitral flow velocity pattern and hemodynamic parameters during preload intervention over the wide range of LA pressure, pulsed Doppler transmitral flow velocity pattern and high-fidelity LA and left ventricular (LV) pressures were simultaneously recorded during rapid volume loading to the LA. Data at three stages, at control, at moderate volume loading (the median LA-to-LV crossover pressure during the volume loading), and at advanced volume loading (the maximal crossover pressure during the volume loading), were compared with one another in 11 dogs. A mean value of E increased with the crossover pressure up to moderate volume loading but did not further increase at advanced volume loading. In the data pooled from all experimental stages in all dogs, the changes in E did not correlate with those in the crossover pressure, but correlated weakly with those in the difference between the crossover pressure and LV minimum pressure (r = 0.45, p < 0.05). E decreased at advanced volume loading in three of 11 dogs with a steep LA pressure drop in early diastole although the changes in the difference between the crossover pressure and LV minimum pressure in the three dogs were similar to those in the other eight dogs. The changes in a rate of LA pressure drop in early diastole associated with advanced volume loading inversely correlated with those in E (r = -0.79, p < 0.01). Thus, E may decrease with an extreme increase in LA pressure; this change may be due to an associated increase in a rate of LA pressure drop in early diastole. This finding suggests that at high LA pressure the increased rate of LA pressure drop in early diastole appears to decrease LV filling and hence to reduce stroke volume.
Animals↗
Dobutamine stress ultrasonic myocardial tissue characterization in patients with dilated cardiomyopathy.
Although acoustic properties of the myocardium are different between patients with cardiomyopathy and normal subjects, the frequency of the abnormal properties in patients with cardiomyopathy is unknown. We assessed the frequency of abnormal acoustic properties of the myocardium detectable with integrated backscatter in patients with cardiomyopathy and attempted more sensitive ultrasonic tissue characterization by combining dobutamine stress testing in patients with cardiomyopathy with apparently normal acoustic properties of the myocardium at rest. The magnitude of cyclic variation of integrated backscatter and calibrated myocardial integrated backscatter at end diastole were measured in 36 normal subjects and 40 patients with dilated cardiomyopathy. Either one of the integrated backscatter parameters was abnormal in 30 of 40 patients with cardiomyopathy. Dobutamine stress ultrasonic tissue characterization was performed in 10 patients with cardiomyopathy with normal values of both integrated backscatter parameters and 10 normal subjects. Calibrated myocardial integrated backscatter did not change during dobutamine infusion in any subject. The magnitude of cyclic variation in integrated backscatter increased in normal subjects but did not change in patients with cardiomyopathy despite a comparative associated increase in the systolic wall thickening during dobutamine infusion. Abnormal acoustic properties are detectable at rest with myocardial integrated backscatter about in three quarters of patients with cardiomyopathy. A combination of dobutamine stress testing would provide more sensitive ultrasonic myocardial tissue characterization and may make it possible to detect subtle changes in the acoustic properties of the myocardium in patients with dilated cardiomyopathy. Therefore dobutamine stress ultrasonic tissue characterization may detect mild dilated cardiomyopathy.
Adult↗
Effect of beta-blockade on regional left ventricular function in patients with dilated cardiomyopathy.
It has been reported that beta-blockade has beneficial effects on the cardiac function and prognosis of patients with congestive heart failure. However, the mechanism for these effects remained unclear. This study compared the use of an angiotensin-converting enzyme (ACE) inhibitor (enalapril, 2.5 to 5.0 mg/day, or delapril, 15 to 30 mg/day) alone with the effects of beta-blockade therapy (metoprolol, 40 to 60 mg/day) coupled with an ACE inhibitor on global and regional left ventricular (LV) function in patients with dilated cardiomyopathy. In 12 patients with dilated cardiomyopathy, the global LV ejection fraction (EF), regional EF (rEF), and regional ejection time (rET) were determined by sector analysis of the radionuclide ventriculogram before and after therapy (duration 14 +/- 9 months). The coefficients of variation of rEF and rET were calculated as indexes of the heterogeneity of regional LV systolic wall motion. EF increased significantly from 20% +/- 8% to 30% +/- 8% (p < 0.05) in patients who received beta-blockade and an ACE inhibitor (n = 5). Furthermore, the coefficients of variation of rET decreased from 27% +/- 13% to 16% +/- 7% (p < 0.05). In contrast, patients treated with an ACE inhibitor only (n = 7) showed no significant improvements in any of these parameters. These results suggest that, compared with an ACE inhibitor alone, beta-blockade improves global and regional LV function in dilated cardiomyopathy by synchronizing myocardial contraction.
Adrenergic beta-Antagonists↗
Residual myocardial damage following electrical injuries.
It is unknown to what degree electrical injury causes cardiac muscle damage. We used standard clinical methods and varying combinations of 201Tl scintigraphy (TI), 123I-metaiodobenzylguanidine scintigraphy, echocardiography, 99mTc-RBC angiography, and coronary catheterization to evaluate five patients with high-tension electrical injuries for cardiac damage. The first follow-up examination was performed within 2 months of injury, and the second follow-up was performed more than 6 months after the first follow-up. Electrocardiographic abnormalities were observed in two patients in the acute stage, but no abnormality was detected in the follow-up period. Myocardial perfusion abnormalities were found in all cases with Tl. The degree of injury indicated by Tl was more severe than that indicated by 123I-metaiodobenzylguanidine scintigraphy. Moreover, Tl showed progression of injury in all cases. These preliminary findings must now be confirmed and verified in a larger group of patients.
3-Iodobenzylguanidine↗