[Prevention and countermeasures in kidney diseases complicated by hypertension].
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Angiotensin II↗
Biomedical subjects
T Kamada
Publications and source records attributed to T Kamada.
[Significance of BUN and non-protein nitrogen analysis in clinical tests].
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Adult↗
[Discrepancies between wall motion abnormalities and regional myocardial perfusion in patients with myocardial infarction: evaluation by myocardial contrast echocardiography].
Regional myocardial perfusions obtained by myocardial contrast echocardiography were compared with wall motion abnormalities evaluated by two-dimensional echocardiography in 26 patients with old myocardial infarction (12 with a QS pattern and 14 with a non-QS pattern on electrocardiograms). Myocardial contrast echocardiography was performed by the intracoronary injection of 2 ml of hand-agitated Urografin-76, and short-axis views of the left ventricle were recorded on VTR. Regional myocardial perfusion was categorized using a three-point scale based on the gray levels, and was compared with wall motion abnormalities of the corresponding region as assessed by two-dimensional echocardiography.
Adult↗
[Regional left ventricular diastolic function in hypertrophic cardiomyopathy: application of "sector analysis" to ECG forward and reverse gated radionuclide ventriculography].
To estimate regional left ventricular (LV) diastolic filling patterns in hypertrophic cardiomyopathy (HCM), a computer-assisted method by applying "sector analysis" to ECG forward and reverse gated radionuclide ventriculography was developed. Fourteen patients with HCM (four with localized septal hypertrophy, seven with apical hypertrophy and three with septal and apical hypertrophy according to echocardiography) were observed at rest. After establishing serial 20 msec imaged frames, the LV region of interest was subdivided into eight sectors radiating from the geometric center. A time-activity curve was generated for each sector and was fitted by third-order harmonics of the Fourier series. From each fitted curve, the regional peak filling rate (rPFR) and the time of rPFR (rTPFR) in the forward gating method and regional atrial contribution to filling (rAC/FV) in the reverse gating method were calculated. The coefficient of variance of rTPFR was used as an index of LV diastolic asynchrony. In HCM, a prominent delay of rTPFR was observed in the hypertrophied regions. The coefficient of variance of rTPFR correlated inversely with global LVPFR (r = -0.62, p less than 0.05), indicating that diastolic asynchrony is one of the determinants of the LV early filling rate. Regional AC/FV was augmented in the hypertrophied regions, indicating the important role of atrial systolic LV filling for slowed early filling. Thus, this new method provides valuable information concerning regional diastolic LV wall mechanics in HCM.
Adult↗
[Clinical evaluation of regurgitant blood flow by rapid cine magnetic resonance imaging in patients with valvular heart disease].
The clinical usefulness of magnetic resonance imaging (MRI) for evaluating regurgitant blood flow in patients with valvular heart disease was studied. The study subjects comprised three healthy volunteers and nine patients with valvular heart disease (aortic regurgitation 3, mitral regurgitation 2, tricuspid regurgitation 2, and pulmonary regurgitation 2). Five were men and seven were women, ranging in age from 31 to 85 years. Valvular heart disease was diagnosed by two-dimensional Doppler echocardiography. MRI was performed using a 1.5 tesla super-conductive magnet system (MAGNETOM, Siemens AG). A rapid MRI technique (fast low-angle shot [FLASH], flip angle = 30 degrees, TR = 65-90 msec, TE = 10-38 msec) was used to generate 11 frames throughout one cardiac cycle in the transaxial, coronal and oblique planes. These sequential frames were displayed in cine mode on a CRT. 1. Intracavitary blood was imaged as a high signal intensity on gradient echo images, while surrounding cardiac structures had somewhat lower signal intensities. 2. In healthy volunteers, systolic ejection blood flow from the left ventricle was observed on coronal images in the cine mode display. The influx of atrial blood into the left and right ventricles was also clearly observed on transaxial cine images. 3. Aortic regurgitant flow was observed as areas of no signal intensity within the left ventricular cavity during diastole on coronal images. 4. Mitral and tricuspid regurgitations were observed within the left and right atria, respectively, as areas of no signal intensity on transaxial images. The extent of regurgitant flow was determined in the vertical long-axis plane, equivalent to the right anterior oblique projection. 5. The vertical oblique scan was suitable for detecting pulmonary regurgitant flow. These results indicate that the rapid cine MRI technique is a useful tool for noninvasively determining regurgitant blood flow in patients with various valvular heart diseases.
Adult↗
[Radiotherapy of a pure seminoma of the testis].
Twenty-six cases of a pure seminoma of the testis that had been treated by postoperative radiotherapy have been reviewed. The overall 5-year survival rate was found to be 92.3%. Further, no severe adverse effects, including sterility, was found. Prophylactic mediastinal radiation is considered to be unnecessary, because supradiaphragmatic lymph node metastasis was seen in only 1 patient, who has remained disease-free 4.5 year after the treatment of a recurrence. Extranodal metastasis was seen 5 cases, 2 of these cases showing bone metastasis that was successfully treated, thereby achieving complete remission. A seminoma is considered to be one of the most curable malignant diseases, however, long-term follow up is a necessity since stage 1 seminoma has been found to show a generalized dissemination after a 16-year, disease-free interval.
Adult↗
[Roles of intrinsic prostaglandins and leukotrienes in gastric mucosal damage].
While gastric mucosa contains prostaglandins and leukotrienes, the roles of these substances in the gastric mucosal protection and damage are not clarified. Using AA-861, a specific 5-lipoxygenase inhibitor, and indomethacin, a cyclooxygenase inhibitor, we investigated the roles of intrinsic prostaglandins and leukotrienes in the gastric circulatory change and the development of gastric lesion induced by ethanol. Rats were fasted for 48 hours and allowed free access to water. After light ether anesthesia, rats were orally given AA-861 (gift from Takeda Chem. Industry; 2.5, 10, 40 or 640 mg/kg), indomethacin (20 mg/kg), and the both or AA-861 (40 mg/kg) and indomethacin (20 mg/kg). Thirty min after the treatment, 2 ml of ethanol (30, 40, 70, 99.5%) was orally administered. Sixty min later, the rats were killed to measure the area of mucosal lesions. The gastric mucosa was damaged by ethanol (greater than or equal to 40%) in a dose-dependent manner. The treatment with AA-861 prohibited the gastric mucosal damage. However, the treatment with indomethacin did not show a significant influence to the mucosal damage. Combined treatment of AA-861 and indomethacin yielded no significant difference from that of single treatment with AA-861 in acute gastric mucosal ulceration. The mucosal blood flow velocity was monitored by laser doppler velocimetry before and after the ethanol administration in the groups treated with vehicle, AA-861 or indomethacin. The blood flow velocity decreased after the administration of 40% ethanol in the group treated with indomethacin, and in a group treated with vehicle.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Polymorphonuclear leukocyte activity and ventricular arrhythmia in acute myocardial infarction.
Polymorphonuclear leukocyte activity was compared with the incidence and severity of ventricular arrhythmia evaluated by Holter electrocardiographic monitoring in 21 patients with acute myocardial infarction. A positive correlation (r = 0.706) was seen between peripheral polymorphonuclear leukocyte count and the amount of leukotriene B4 produced by A23187 (20 microM)-stimulated polymorphonuclear leukocytes on the first hospital day (p less than 0.01). Patients were divided into 3 groups according to the severity of ventricular arrhythmia: no or mild (unifocal, maximal hourly ventricular premature complex rate less than 30, n = 6), moderate (maximal hourly ventricular premature complex rate greater than or equal to 30 or multifocal, n = 6) or severe (R on T, greater than or equal to 2 consecutive ventricular premature complexes or ventricular fibrillation, n = 9). Polymorphonuclear leukocyte count and its leukotriene B4 production were increased with the increase in severity of ventricular arrhythmia among 3 groups. Polymorphonuclear leukocyte count (13,300 +/- 900/microliter, mean +/- standard error of the mean) and its leukotriene B4 production (194 +/- 24 ng/10(7) cells) in patients exhibiting severe ventricular arrhythmia were significantly increased compared with those in patients exhibiting no or mild ventricular arrhythmia (10,300 +/- 1,000/microliter, p less than 0.05 and 120 +/- 21 ng/10(7) cells, p less than 0.05, respectively). Enzymatically estimated infarct size in the latter patient group was significantly smaller than those of the other 2 groups, between which there was no difference in infarct size. These results suggest that polymorphonuclear leukocyte activity is closely related to the incidence and severity of ventricular arrhythmia during the early phase of myocardial infarction.
Arrhythmias, Cardiac↗
Effect of hepatic blood oxygenation on bile secretion in rats.
The effect of hepatic hemodynamics and hepatic tissue blood oxygenation on bile flow was studied in anesthetized rats by reflectance spectrophotometry. The hepatic hemodynamics and blood oxygenation were assessed by reflectance spectrophotometry. The hepatic ischemia was induced by partial ligation of portal vein and hepatic hypoxia was induced by inhalation of low concentration of oxygen. 1. The ischemia decreased hepatic blood volume index and hepatic blood oxygenation, and diminished bile flow. 2. Respiratory hypoxia suppressed hepatic oxygenation with minimal change of hepatic blood volume, and it also reduced the bile flow. 3. Bile flow was related hyperbolically with hepatic oxygenation and its dependency in hepatic ischemia and respiratory hepatic blood hypoxia identical. It is concluded that the hepatic tissue blood oxygenation affects hepatic energy metabolism, thus affecting the bile secretion.
Animals↗
In vivo estimation of oxygen saturation of hemoglobin in hepatic lobules in rats.
We developed a system for the in vivo estimation of oxygen saturation of hemoglobin in the sinusoidal blood of periportal and pericentral regions of hepatic lobules in rats. There was a marked heterogeneity in blood oxygenation and oxygen gradients within hepatic lobules. The sinusoidal blood oxygenation was reduced in some pericentral regions within hepatic lobules following acute ethanol ingestion, suggesting an occurrence of perivenular hypoxia in the liver after acute ethanol consumption.
Animals↗
The effect of CV-4151, a selective inhibitor of thromboxane synthetase, on prostanoid formation and platelet aggregation in humans.
The pharmacokinetics and pharmacologic effects of a potent, selective inhibitor of thromboxane synthetase, CV-4151 [(E)-7-phenyl-7-(3-pyridyl)-6-heptenoic acid] on prostanoid formation and platelet aggregation were studied in 42 healthy male volunteers. The drug was well tolerated. After oral administration of 10 to 100 mg of CV-4151, peak plasma levels of 1-6 micrograms/mL were reached in a dose-dependent manner within 1 hour. Elimination followed first-order fashion with elimination half-life of about 1 hour. Serum levels of thromboxane B2 reduced to 4% to 15% of control at 2 hours after drug ingestion dose-dependently. Serum levels of 6-keto-prostaglandin F1 alpha increased to about four to six times basal levels. Platelet aggregation induced by collagen and arachidonate was inhibited in most cases. Such pharmacologic effects outlasted serum drug levels. In repeated administration, stable inhibition of serum thromboxane B2 production and platelet aggregation in proportion to the enhancement of serum 6-keto-prostaglandin F1 alpha production was observed although no drug accumulation was found. These results indicate that CV-4151 may be suitable for clinical trials in cardiovascular diseases in which imbalance between thromboxane and prostacyclin may be involved in the pathogenesis.
Adult↗
Urinary excretion of frusemide and its metabolites in a diabetic nephropathy patient.
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Aged↗
Levallorphan and dynorphin improve motor dysfunction in Mongolian gerbils with unilateral carotid occlusion: the first application of the inclined plane method in the experimental cerebral ischemia.
Levallorphan and dynorphin were effective on the motor dysfunction in the gerbil model of unilateral cerebral ischemia. The effect of opioids, levallorphan (mixed agonist-antagonist), dynorphin (kappa-receptor agonist) and naloxone (mu-receptor antagonist), on neurological impairment was evaluated using the unilateral cerebral ischemia model of gerbil. Motor function was evaluated quantitatively by using the inclined plane method. Both levallorphan-treated group and dynorphin-treated group showed a significant improvement of the motor dysfunction compared with saline-control group. On the other hand, naloxone-treated group did not differ from saline-control group. The beneficial effect of these opioids on motor dysfunction might be mediated by the kappa-opioid receptor. This study also showed the potential usefulness of the inclined plane method for the investigation on the cerebral ischemia.
Animals↗
Carbondioxide reactivity of the blood flow in human basilar artery estimated by the transcranial Doppler method in normal men: a comparison with that of the middle cerebral artery.
Using the transcranial Doppler technique, the carbondioxide reactivity of the blood flow velocity in the human basilar artery (BA) was investigated in healthy volunteers for comparison with that in the middle cerebral artery (MCA). An exponential curve with an exponent of 0.044 mmHg-1 was found to be a good fit to the BA data and 0.040 mmHg-1 to the MCA data, respectively. While the response of both arteries showed a good correlation to the end-tidal carbondioxide partial pressure (PETCO2), there was no significant difference observed between the carbondioxide (CO2) reactivity of each artery. In both arteries, the end-diastolic flow velocity decreased significantly with the reduction of PETCO2, which may represent the increasing resistance of cerebral microvasculature in hypocapnia. Because of the reliability and noninvasiveness of this method, this normal value should be quite helpful for the bed-side evaluation of an altered CO2 response in the patients with cerebrovascular disease.
Adult↗
Efficacy of echo-Doppler examination for the evaluation of renovascular disease.
The accuracy of the diagnosis of renal artery stenosis using noninvasive echo-Doppler velocimetry was compared with that of angiography in 40 renal arteries. The duplex-Doppler signals were detected through the muscle of the back (the translumbar approach). Renal artery stenosis was diagnosed by three objectively defined Doppler parameters, the acceleration index (AI), the acceleration time (AT), and the acceleration time ratio (ATR). The normal range obtained on 11 control subjects was defined as AI greater than or equal to 3.78, AT less than or equal to 0.07 s, and ATR less than or equal to 1.35. High technological success (98%) was obtained using the translumbar approach. In comparison with angiography (cases of significant stenosis), the accuracy of the echo-Doppler method using the criteria of the AI was 95%, the sensitivity was 100%, and the specificity was 93%. This noninvasive method may be one of the most accurate screening methods for diagnosing significant renal artery stenosis.
Blood Flow Velocity↗
Effects of changes in coronary stenosis on left ventricular diastolic filling assessed with pulsed Doppler echocardiography.
To determine the effects of changes in coronary stenosis on left ventricular diastolic filling, diastolic filling was serially examined before and after percutaneous transluminal coronary angioplasty using pulsed Doppler echocardiography in 50 patients with stable exertional angina pectoris. Peak rapid filling velocity and the ratio of peak atrial filling to peak rapid filling velocities were measured from the transmitral flow velocity pattern before and 2 and 9 days after coronary angioplasty. Peak rapid filling velocity increased and the ratio of peak atrial filling to peak rapid filling velocities decreased gradually after coronary angioplasty. The improvement in left ventricular diastolic filling was greater in patients with severe (greater than 90%) coronary stenosis than in patients with mild (less than or equal to 90%) coronary stenosis. In the long-term follow-up period, the improved left ventricular diastolic filling worsened in only 11 patients with marked progression to greater than 90% coronary stenosis. Thus, left ventricular diastolic filling improved gradually after coronary angioplasty, possibly reflecting post-ischemic "stunned" myocardium. Serial examinations of left ventricular diastolic filling with pulsed Doppler echocardiography may be a means of noninvasively assessing the temporal changes in the coronary stenosis and predicting the occurrence of coronary restenosis after coronary angioplasty.
Adult↗
Changes in aerobic and anaerobic ATP-synthesizing activities in hypoxic mouse brain.
The changes in cerebral metabolism in mice in severe hypoxia were investigated by analyses of changes in the levels of energy metabolites and near-infrared spectrophotometric assessment of the states of hemoglobin and cytochrome oxidase. Under 4.4% O2, the contribution of anaerobic ATP production was at most about 20% of the demand. However, the cerebral ATP level was kept at the control level until about 1 min before death. Pentobarbital anesthesia, which reduced the cerebral rate of metabolism, prolonged the survival time, although anaerobic ATP production still did not support ATP demand. Under these conditions, deoxygenation of hemoglobin and reduction of cytochrome oxidase proceeded rapidly within 1 min. Hemoglobin reached the maximum state of deoxygenation in the middle phase of hypoxia, with no further change until death. However, cytochrome oxidase was reduced slowly with one phase of partial reoxidation due to increase of cerebral blood volume, and reached the completely reduced state at death. From these results it was concluded that the aerobic ATP synthesis, which supplied more than 80% of the cerebral demand, decreased gradually because of limitation of oxygen supply, and that the failure of oxidative phosphorylation to meet demand triggered the decrease in the cellular ATP level that led to death.
Adenosine Diphosphate↗
Microvascular basis of gastric mucosal protection.
The gastric microcirculation was investigated with the in vivo microscopic analyzing system and reflectance spectrophotometry. The topical administration of either ethanol (greater than or equal to 20%), indomethacin (0.1 mg/kg), leukotriene C4 (0.1 microgram), and platelet activating factor (PAF) (125 micrograms) decreased mucosal blood flow and mucosal blood oxygenation. The subsequent reperfusion of blood and/or addition of hydrocholoride (0.2 N) induced the gastric bleeding and ulceration. Pretreatment with calcium channel blockers (verapamil, flunaridine, and diltiazem) significantly reduced the gastric lesions induced by mucosal ischemia followed by reperfusion. Lipid peroxidation increased only after reperfusion, which was also blocked by pretreatment with calcium channel blockers. Thus, the calcium ion influx and the membrane lipid peroxidation followed by mucosal hypoxia might have a role in the mucosal cell death. The results indicate that the gastric surface mucosal circulation plays an important role in the mucosal protection against high concentrations of ethanol, nonsteroidal anti-inflammatory drugs (NSAIDs), PAF, and leukotriene C4.
Animals↗