Biomedical subjects

K Hiwada

Publications and source records attributed to K Hiwada.

At least 235 records · Page 13Linked to original sources

PubMed1993

Precise assessment of myocardial damage associated with secondary cardiomyopathies by use of Gd-DTPA-enhanced magnetic resonance imaging.

To evaluate the myocardial damage in patients with secondary cardiomyopathies, the authors examined gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) in 5 patients (2 with cardiac amyloidosis, 2 with acute myocarditis, 1 with cardiac thyrotoxicosis). MR images were performed at 1.5-T by using a spin echo pulse sequence before and after intravenous administration of Gd-DTPA (0.2 mmol/kg). All patients revealed distinct high-intensity areas on postcontrast images. Moreover, MRI with Gd-DTPA could determine the severity and precise regions of myocardial damage associated with secondary cardiomyopathies. It is suggested that gated cardiac MRI with Gd-DTPA enhancement is useful for detecting the myocardial damage in secondary cardiomyopathies.

Acute Disease↗

PubMed1993

Effects of glyceryl trinitrate on blood pressure and arterial compliance.

Glyceryl trinitrate (GTN) mainly reduces systolic blood pressure (SBP) rather than diastolic blood pressure (DBP) in acute conditions. To examine the efficacy of GTN as an antihypertensive agent in patients with isolated systolic hypertension (ISH), the authors examined the effects of GTN on BP and arterial compliance (AC) in patients who underwent cardiac catheterization. Seventy patients (with old myocardial infarction, 36; angina pectoris, 25; chest pain syndrome, 9) who underwent cardiac catheterization because of chest pain were included in this study. They were aged between thirty-seven and seventy-four (mean sixty-one) years. According to the levels of BP at cardiac catheterization, the authors selected two subgroups: the normotensive group (NT group, n = 18) and the isolated systolic hypertensive group (ISH group, n = 20) from all subjects. The authors measured BP before and after (three minutes) sublingual administration of GTN (0.3 mg) at the cardiac catheterization. AC was assessed by means of diastolic pressure decay. The change of BP was estimated by the differences between values before and at three minutes after GTN. After administration of GTN, SBP was decreased significantly from 157 +/- 25 to 142 +/- 23 mmHg (P < 0.01), while DBP did not change (83 +/- 13 vs 84 +/- 15 mmHg). The change in SBP was positively correlated with the pretreatment SBP and negatively correlated with AC (r = 0.51, P < 0.001; r = 0.39, P < 0.001, respectively). AC was significantly lower in the ISH group than in the NT group (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Morphological characteristics of hypertrophic cardiomyopathy estimated by left ventriculography.

To determine the common morphological characteristics of hypertrophic cardiomyopathy (HCM) by ventriculography from a right anterior oblique projection, diaphragmatic and free wall configurations were analyzed in 15 patients with obstructive HCM (HOCM), 32 patients with nonobstructive HCM (HNCM) and 17 controls. There was a convexity extending into the left ventricle in the right anterior oblique projection due to hypertrophy of the interventricular septum (IVS) in all patients with HCM. The peak convexity, where septal thickness was maximal (M point), was closer to the base in HOCM than in HNCM. Due to this convexity, the left ventricle showed a catenoid-shaped distortion at the M point. The distortion was severer in HOCM than in HNCM. Left ventricular free wall (LVFW) thickness was measured at the base and near the apex. LVFW thickness in HOCM decreased toward the apex, similar to that in controls, but in 17 of 32 HNCM (53%) LVFW thickness increased toward the apex. Cardiac index and stroke index in HCM were significantly smaller than those in controls. There was a significant correlation between the position of the M point and stroke index in HCM. These results indicate that a common morphological characteristic of HCM on the diaphragmatic side is the existence of a convexity extending into the left ventricle, and that cardiac performance in HCM is greatly influenced by the nature of the convexity. Myocardial abnormality seems to exist primarily at the base of the IVS in HOCM, and primarily in the lower part of the IVS and LVFW in HNCM.

Adult↗

PubMed1993

Aortic valvular disease and right coronary artery stenosis induced by mediastinal irradiation--report of a case.

This report presents a case of aortic valvular dysfunction and right coronary artery disease following radiation therapy on the mediastinum. A 61-year-old woman had received mediastinal radiation for the treatment of right mammary cancer 20 years previously. She developed symptoms of congestive heart failure 6 months ago. The patient was found to have aortic valvular dysfunction and proximal stenosis of the right coronary artery. Surgical aortic valve replacement improved cardiac status, and vasodilator treatment reduced ischemia due to right coronary artery stenosis.

Aortic Valve↗

PubMed1993

Acetaminophen-induced eosinophilic pneumonia.

We present the first case (to our knowledge) of acetaminophen-induced eosinophilic pneumonia. Although the patient had taken an acetaminophen-containing combination drug, Kinuya-chinnetsu, for only three days, the abnormal shadow on his chest radiograph continued for about a month. Lymphocyte stimulation tests showed that both Kinuya-chinnetsu and acetaminophen induced the proliferation of peripheral blood lymphocytes.

Acetaminophen↗

PubMed1993

An adult case with multiple cardiac valve prolapse and regurgitation.

A 56-year-old female had pure regurgitation in all cardiac valves. Color Doppler echocardiography showed a regurgitant jet in all cardiac valves. The severity of regurgitation due to the prolapse in all valves was moderate. The patient had no history of rheumatic fever, ischemic heart disease, endocarditis or hypertension. Physical characteristics of the patient were neither of Marfan's nor Ehlers-Danlos' syndrome. The etiology of regurgitation in all cardiac valves of this patient may be due to multiple valve prolapse.

Aortic Valve Insufficiency↗

PubMed1993

[A case of diffuse panbronchiolitis associated with tracheomalacia].

A 71-year-old male had suffered from cough with purulent sputum. He was admitted to our hospital because of worsening of his symptoms. The chest X-ray film showed diffuse nodular shadows and emphysematous changes in both lung fields. Transbronchial lung biopsy demonstrated findings compatible with diffuse panbronchiolitis (DPB). Bronchoscopy showed the tracheal lumen was sagittaly narrowed and membranous portion was protruded into the lumen. The trachea completely collapsed when coughing. His disease was diagnosed as saber-sheath type tracheomalacia (Johnson III). Tracheomalacia was reported to be observed in 0.9% of patients examined by bronchoscopy. The dominant type of tracheomalacia is crescent type, and saber-sheath type is rare. Chronic airway inflammation with DPB might have exacerbated the tracheomalacia in this case.

Aged↗

PubMed1993

Restriction fragment length polymorphisms of the human renin gene: association study with a family history of essential hypertension.

The aim of this study was to elucidate whether human renin gene restriction fragment length polymorphism (RFLP) is associated with essential hypertension. We sampled randomly 45 inpatients at our hospital and divided them into two groups according to a family history of essential hypertension, FH(-) and FH(+) groups. The FH(+) group was further divided into two subgroups based on the level of BP, FH(+) x HT(-) and FH(+) x HT(+) groups. The frequencies of renin gene RFLP patterns were compared among three groups: FH(-), FH(+) x HT(-) and FH(+) x HT(-). Among 18 restriction endonucleases tested, renin gene RFLPs were detected by three restriction endonucleases, Mbo I, Bg I and Hind III, digestion. There was a significant difference in the distribution of renin gene Mbo I genotypes among the three groups (chi 2 = 13.284, P < 0.01). The distribution of Mbo I genotypes in the FH(-) group was different from FH(+) x HT(-) group (chi 2 = 5.990, P < 0.05) and FH(+) x HT(+) group (chi = 9.210, P < 0.01), but there was no significant difference between the FH(+) x HT(-) and FH(+) x HT(+) groups. The distribution of renin gene Bgl I and Hind III genotypes were similar in the three groups, FH(-), FH(+) x HT(-) and FH(+) x HT(+). These results indicate that human renin gene Mbo I RFLP is significantly associated with a family history of essential hypertension.

Adolescent↗

PubMed1993

Left ventricular cardiac structure and diastolic function in isolated systolic hypertension in the elderly.

We examined the left ventricular cardiac structure and the diastolic function in patients with isolated systolic hypertension (ISH; SBP > or = 160 mmHg and DBP < 90 mmHg) in the elderly. We studied 17 patients with ISH, 24 age-matched patients with essential hypertension (EHT; DBP > or = 90 mmHg) and 17 normotensive controls (NT; SBP < 140 mmHg and DBP < 90 mmHg). EHT were divided into two groups based on the mean wall thickness (MWT) of the left ventricle. Group 1 patients (EHT-I, n = 12) had a MWT < 10 mm and group 2 patients (EHT-II, n = 12) had a MWT > or = 10 mm. We measured left ventricular end-diastolic dimension (LVDd), end-systolic dimensions (LVDs), left ventricular mass index (LVMi) and left ventricular isovolumic relaxation time (IRT) to assess the left ventricular cardiac structure and the diastolic function by M-mode echocardiography. LVDd was significantly smaller in ISH than in NT, EHT-I and EHT-II (P < 0.01). Relative wall thickness was greatest in ISH because of both the decreased chamber size and the increased left ventricular wall thickness. LVMi in ISH was similar to that in EHT-I, but IRT in ISH was significantly longer than that in EHT-I (P < 0.05). These results suggest that ISH in the elderly shows a left ventricular concentric hypertrophy and a severely impaired diastolic function.

Aged↗

PubMed1992

Differential gene expression and regulation of type-1 angiotensin II receptor subtypes in the rat.

A simplified and sensitive method for measuring expression levels of type-1 angiotensin II (AT1) receptor subtypes, AT1A and AT1B, was established. The two receptor cDNAs were co-amplified and measured by polymerase chain reaction using primers based on the corresponding receptor subtype genes. Both AT1A and AT1B mRNAs were widely expressed in the rat tissues including adrenal gland, kidney, heart, aorta, lung, liver, testis, pituitary gland, cerebrum and cerebellum. AT1A mRNA was predominantly expressed in the rat tissues examined except adrenal gland and pituitary gland where AT1B mRNA was predominantly expressed. Sodium depletion did not change mRNA levels of AT1A and AT1B in the all tissues. However, both AT1A and AT1B mRNA levels in the heart and aorta were down-regulated by treatment with AT1 specific antagonist, TCV 116. In contrast, AT1B mRNA in the adrenal gland was mainly reduced by the treatment. These results suggest that the expression level of AT1B mRNA in the adrenal gland depends on the activity of the renin-angiotensin-aldosterone system (RAAS) and both receptor subtypes mediate contraction and hypertrophy of the smooth and cardiac muscles via the RAAS.

Angiotensin II↗

PubMed1992

Effects of a long-term treatment with alacepril on left ventricular hypertrophy and function in patients with essential hypertension.

The authors examined the effects of a long-term treatment with the angiotensin-converting enzyme inhibitor, alacepril, with respect to the reversal of left ventricular hypertrophy and the improvement of left ventricular function. Ten uncomplicated essential hypertensive patients with left ventricular hypertrophy, aged 53 +/- 8 years, were treated with alacepril alone for 12 months. All patients underwent echocardiography to to assess left ventricular dimensions and function before and after the treatment. After the treatment, blood pressure was decreased significantly from 163 +/- 14.1/98 +/- 4.2 to 142 +/- 20.3/86 +/- 11.0 mm Hg (each, P less than .01), whereas heart rate did not change (66 +/- 6 versus 69 +/- 8 beats/min). The left ventricular mass index was decreased significantly from 146 +/- 27 to 119 +/- 29 g/m2 (P less than .01). Ejection fraction, fractional shortening, peak shortening rate, and peak lengthening rate all improved significantly after the treatment. There was a significant inverse relationship between fractional shortening and end-systolic wall stress before the treatment (r = .63, P less than .05), and this relationship did not change after the treatment. It is concluded that alacepril improved both left ventricular systolic and diastolic function without causing any consistent augmentation of left ventricular contractility.

Adult↗

PubMed1992

Effect of disopyramide on left ventricular diastolic function in patients with hypertrophic cardiomyopathy: comparison with diltiazem.

Left ventricular diastolic function before and after the administration of disopyramide (100 mg) or diltiazem (30 mg) was assessed in 10 patients with nonobstructive type hypertrophic cardiomyopathy. Left ventricular diastolic function was assessed by Doppler echocardiography. The peak early (E) and late (A) diastolic flow velocities and E/A ratio (E/A) were measured. Three hours after the administration of disopyramide, blood pressure did not significantly change, but heart rate was decreased significantly (p less than 0.01). Disopyramide increased the E velocity and E/A ratio from 43.8 +/- 15.0 cm/sec to 51.3 +/- 16.1 cm/sec and from 0.71 +/- 0.20 to 1.00 +/- 0.24 (each p less than 0.01), respectively, and decreased the A velocity from 63.9 +/- 18.5 cm/sec to 52.1 +/- 14.9 cm/sec (p less than 0.01). Diltiazem increased the E velocity and E/A ratio from 42.8 +/- 12.5 cm/sec to 46.4 +/- 13.4 cm/sec (p less than 0.05) and from 0.74 +/- 0.21 to 0.96 +/- 0.28 (p less than 0.01), respectively, and decreased the A velocity from 60.6 +/- 16.4 cm/sec to 50.2 +/- 15.6 cm/sec (p less than 0.01). These results indicate that disopyramide improved left ventricular diastolic filling in hypertrophic cardiomyopathy, and its effect was similar to that of diltiazem.

Adult↗

PubMed1992

A large conus artery in patients with hypertrophic cardiomyopathy.

We retrospectively analyzed coronary arteriograms in 66 patients with hypertrophic cardiomyopathy (HCM) who underwent coronary arteriography. Four of these patients showed a large conus artery supplying the interventricular septum, and the characteristics of their echocardiograms revealed a marked interventricular septal hypertrophy. It is suggested that in some patients with HCM, the conus artery may develop in compensation for the relatively reduced coronary blood flow which is due to the hypertrophied myocardium.

Adult↗

PubMed1992

Response of plasma renin-angiotensin system to a single captopril administration in patients receiving long-term treatment with captopril.

1. The responses of angiotensin II (AII), AIII, aldosterone and plasma renin activity (PRA) to a single dose of captopril were investigated in hypertensive patients receiving long-term (more than 1 year) captopril therapy (CT patients) and compared with those of non-treated hypertensive patients (NT patients). 2. Baseline levels of AII and aldosterone were significantly lower in CT patients than in NT patients. AIII tended to be lower and PRA was slightly higher in CT than in NT patients, but these differences were not significant. 3. A single administration of captopril (50 mg orally) significantly decreased plasma levels of AII, AIII and aldosterone as well as blood pressure in both CT and NT patients. 4. These results demonstrate that chronically repeated administration of captopril to hypertensive patients effectively reduces the daily blood pressure and concomitantly the plasma AII level to acceptable levels in patients with no experience of ACE inhibition.

Aldosterone↗

PubMed1992

Analysis of blood flow patterns in aortic aneurysm by cine magnetic resonance imaging--a review of case material.

Cine magnetic resonance imaging (MRI) (0.5-T) using rephased gradient echo technique was performed in 5 normal volunteers and 14 patients with aortic aneurysm to study the patterns of blood flow in aortic aneurysm. In the transaxial section, blood flow in normal aorta appeared as homogeneous and high intensity during systole. Blood flow in aneurysm appeared as inhomogeneous flow enhancement with flow void. In the sagittal scan, the homogeneous flow enhancement in normal aorta was also observed during systole, and its apex of flow enhancement was "taper." The blood flow patterns in aneurysm were classified as "irregular," "zonal," "eddy," and "obscure," depending on the contrast of flow enhancement and flow void. Their apexes were "taper" or "round." When the size of aneurysm became larger, the flow pattern in aneurysm tended to become "eddy" or "obscure" and the flow enhancement became "round." Though the exact mechanism of abnormal flow patterns in aneurysm remains to be determined, cine MRI gives helpful information in assessing blood flow dynamics in aneurysm.

Adult↗

PubMed1992

Clinical significance of the calcification of coronary arteries in patients with angiographically normal coronary arteries.

In order to clarify the clinical significance of coronary calcification in patients with angiographically normal coronary arteries, exercise electrocardiography was used and left ventricular function was examined noninvasively and invasively. The patient groups were as follows: (1) patients with coronary artery calcification on only the left anterior descending artery but no narrowing lesion on any other arteries (calcified group), (2) patients with a significant stenosis on only the left anterior descending artery (stenotic group), and (3) the control group. The left ventricular function in the calcified group, as indicated by systolic time intervals and invasive parameters such as ejection fraction and mean systolic ejection rate, showed a depression similar to that in the stenotic group, compared with the control group. The incidence of electrocardiographically ischemic responses to exercise testing was significantly higher in the calcified group (75%, p less than 0.01) and the stenotic group (68%, p less than 0.01) than in the control group (25%). Exercise tolerance time and the maximum double product were markedly smaller in the calcified and the stenotic groups as compared with the control group. These results indicate that the left ventricular function and coronary reserve in the calcified group were reduced and almost identical with those in the stenotic group. The authors conclude that a calcified coronary artery, even if patent, cannot supply an adequate blood flow for the myocardium, resulting in impaired left ventricular function.

Angina Pectoris↗

PubMed1992

Hemodynamic characteristics of patients with coronary artery disease presenting false-negative exercise stress test.

The present study was designed to clarify the characteristics of left ventricular hemodynamics and coronary arteries in patients with coronary artery disease presenting false-negative response to the Master's two-step stress test. Eighty-eight consecutive patients performed the Master's two-step stress test and had coronary angiography for evaluation of suspected or known coronary artery disease. The frequency of false-negative and true-positive responses in the Master's two-step stress test was 20% and 45%, respectively. Elevated left ventricular end-diastolic pressure, reduced ejection fraction, and low cardiac output characterized the left ventricular hemodynamics in patients with false-negative responses, as compared with those with true-positive response. The severity and extent of coronary artery disease, as well as prior myocardial infarction, did not affect the frequency of false-negative response. This study indicates that the false-negative response to the Master's two-step test is unexpectedly frequent in coronary artery disease with severe left ventricular dysfunction. Thus, one should be careful in judging the results of the Master's two-step test in symptomatic patients with severe left ventricular dysfunction.

Adult↗

PubMed1992

Effect of L-threo-3, 4-dihydroxyphenylserine on orthostatic hypotension in a patient with spinal cord injury.

A 72-year-old female who underwent the extirpation of metastatic intraspinal tumor showed an extremely wide variation of blood pressure with recurrent episodes of syncope due to paroxysmal hypotension. Treatment of the patient with salt supplement and L-threo-3, 4-dihydroxyphenylserine, an exogenous precursor of norepinephrine, markedly improved the syncopal attack as well as the daily activity.

Adenocarcinoma↗