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Biomedical subjects

H Hirakata

Publications and source records attributed to H Hirakata.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Two cases of huge hepatic hemangioma].

We have experienced two cases of huge hepatic hemangioma. Case 1 was a 51-year-old man complaining of abdominal fullness and was shown low density area in the right hepatic lobe by abdominal computed tomography. He was treated with segmentectomy of the right hepatic lobe. The resected specimen was histologically diagnosed as cavernous hemangioma. Case 2 was a 61-year-old man who showed no symptom and was shown 10 x 6.5 cm hemangioma by abdominal ultrasonography. He have been untreated. For 10 years, 29 cases of huge hepatic hemangioma, including our two cases have been reported in Japan. The female to male ratio is 5:1. The incidence of huge hepatic hemangioma was frequent in the fifth and sixth decades of life. The majority of patients complained of palpable abdominal mass and abdominal pain. The dominant site of huge hepatic hemangioma was the anatomical right hepatic lobe.

Hemangioma, Cavernous↗
PubMed1992

Direct vasoconstrictor and vasodilator effects of propofol in isolated dog arteries.

We have measured the direct effects of propofol 10(-7)-10(-4) mol litre-1 on isolated canine cerebral, coronary, mesenteric, femoral and renal arteries. In arterial strips precontracted submaximally with potassium chloride or prostaglandin F2 alpha (PGF2 alpha), propofol induced further contractions at low concentrations (10(-6)-10(-5) mol litre-1) and relaxation at high concentrations (10(-4) mol litre-1). Intrafat, which contains soya bean oil, egg phosphatide and glycerol in similar concentration to the emulsion formulation of propofol, had a small relaxant effect at a concentration corresponding to propofol 10(-4) mol litre-1. In humans, clinically relevant plasma concentrations of propofol have been reported to be 1-5 x 10(-5) mol litre-1, 97-99% of which is bound to plasma proteins. Therefore, the results obtained in this study demonstrated that clinically relevant concentrations of propofol did not have direct vasodilator effects.

Animals↗
PubMed1992

CBF and oxygen metabolism in hemodialysis patients: effects of anemia correction with recombinant human EPO.

To investigate the effects of anemia correction with recombinant human erythropoietin (rhEPO) on both cerebral blood flow and oxygen metabolism in hemodialysis (HD) patients, the regional cerebral blood flow (rCBF), oxygen extraction (rOEF), and metabolic rate for oxygen (rCMRO2) were measured by positron emission tomography in five HD patients, and the data were compared with eight nondemented controls who had neither anemia nor uremia. In the HD patients, 1,500 U of rhEPO were administered intravenously three times a week to achieve a 10% increase in hematocrit (Hct) as an absolute value. Before rhEPO administration, the hemispheric rCMRO2 in HD patients was 1.48 +/- 0.09 (SE) ml.min-1.100 ml-1, which was significantly lower than that of 2.18 +/- 0.10 in the controls (P less than 0.01). In contrast, both rCBF and rOEF were significantly greater in the HD patients than the control, being 40 +/- 3 vs. 32 +/- 3 ml.min-1.100 ml-1 for rCBF (P less than 0.02) and 49 +/- 1 vs. 38 +/- 1% for rOEF (P less than 0.001). After treatment with rhEPO, Hct rose significantly from 21 +/- 1 to 31 +/- 1% in HD patients (P less than 0.001). There were significant reductions in both the hemispheric rCBF to 32 +/- 1 ml.min-1.100 ml-1 (P less than 0.01) and rOEF to 42 +/- 1% (P less than 0.01). However, the hemispheric rCMRO2 remained low at 1.58 +/- 0.06 ml.min-1.100 ml-1 even after rhEPO treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effects of a new calcium antagonist, manidipine, on the renal hemodynamics and the vasoactive humoral factors in patients with diabetes mellitus.

The effects of manidipine (10 mg/day for 7 days) on the renal hemodynamics and vasoactive humoral factors were examined in 6 adults with diabetes mellitus (DM). Mean duration of DM was 9 +/- 2 years; serum creatinine concentration was 0.9 +/- 0.04 mg/dL. Plasma endothelin-1 (ET-1) concentration was 5.4 +/- 0.7 pg/mL before manidipine, compared with 1.9 +/- 0.2 pg/mL in 14 controls (p = 0.03%). Systolic and mean blood pressure decreased significantly during treatment without changes in glomerular filtration rate, renal plasma flow, or filtration fraction. Renal vascular resistance tended to decrease and fractional excretion of sodium significantly increased from 1.35 +/- 0.27% to 2.06 +/- 0.47 (p = 2.96%). ET-1 significantly decreased from 5.4 +/- 0.7 pg/mL to 3.5 +/- 0.6 (p = 2.95%), while plasma angiotensin II, atrial natriuretic factor, urinary excretion rate of ET-1, and albumin excretion rate did not change. Manidipine lowers blood pressure without adversely affecting renal function in diabetic patients. Manidipine, which lowers ET-1, may protect from progressive renal injury in diabetics.

Adult↗
PubMed1991

[Significance of transrectal hyperthermia in the treatment of benign prostatic hyperplasia].

Though the local hyperthermia for the management of benign prostatic hyperplasia has drawn much attention as one non-surgical treatment, no definite conclusion could yet be obtained in terms of the efficacy. In this study local hyperthermia was induced in evaluable 33 cases with benign prostatic hyperplasia using Primus, and the effectiveness of this modality of treatment was investigated by analysing the subjective and objective response following hyperthermia. The prostate was heated trans-rectally up to 43 degrees C with 915 MHz microwave for one hour. Hyperthermia was carried out twice a week for ten times for the sake of thermotolerance. Urinary obstructive symptoms were divided into diurnal and nocturnal frequency, urinary urgency, the degree of urinary stream, hesitancy and dribbling. Each symptom was described before and after the treatment according to the scoring system. Moreover, objective changes of urinary flow and prostatic size were estimated by the residual urine volume, uro-flowmetry, rectal palpation of the prostate and echography. Hyperthermic treatment improved urinary flow markedly, but no appreciable alteration could be observed as to the size of the prostate. The overall efficacy, including subjective and objective response, could be summarized as 37% of effectiveness, and 33% of slight effectiveness, that is, 70% of effective ratio. As to the side effect, anal pain was noted in few cases of the present series. Therefore, transrectal hyperthermia may be a suitable modality for non-surgical treatment of benign prostatic hyperplasia.

Evaluation Studies as Topic↗
PubMed1990

Angiotensins and the failing heart. Enhanced positive inotropic response to angiotensin I in cardiomyopathic hamster heart in the presence of captopril.

We examined the hypothesis that the positive inotropic effect of angiotensin I (Ang I) may be retained in the presence of angiotensin converting enzyme inhibitors so that it may have a direct beneficial effect on the heart. Accordingly, isolated perfused hearts (Langendorff preparation) of 300-day-old cardiomyopathic hamsters (a model of spontaneous cardiomyopathy) and age-matched normal hamsters (controls) were infused with Ang I in the presence of captopril; propranolol was added to the perfusing medium to block catecholamine-mediated effects of angiotensins on the heart. Left ventricular developed pressure and the rate of increase in left ventricular developed pressure increased significantly (p less than 0.001) in both the cardiomyopathic and the normal hamster heart despite concomitant reduction in myocardial flow rate favoring a direct inotropic effect of Ang I in both normal and myopathic hearts; these changes were significantly higher by almost threefold in the cardiomyopathic than in the normal hamsters (p less than 0.01) and were blocked by the angiotensin II (Ang II) antagonist [Sar1,Thr8]Ang II. Comparing dose-left ventricular contractility response curves for Ang I and Ang II, ED50 for responses was identical in both normal and myopathic hearts, whereas peak responses to Ang II were double those to Ang I in normal hearts but were almost identical in the myopathic hearts. Binding of [125I]Ang II in six cardiomyopathic and four normal hamster hearts was of high affinity, but there was no evidence for Ang I-saturable high-affinity binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin I↗
PubMed1988

The differential effects of alpha 2-adrenergic stimulation on the myocardium and coronary vessels in the isolated rat heart.

The differential effects of alpha 2-adrenoceptor stimulation on myocardial contractility and coronary circulation were examined in the isolated perfused rat heart. We studied 20 Sprague-Dawley rats of similar age (26-28 weeks) and body weight (500-550 gm). Myocardial contractility (LV +dp/dt and developed pressure, LVP) and coronary flow resistance (CFR) were tested in the isolated isovolumic hearts using Langendorff preparation at a constant perfusion rate (2.5 ml/min/100 g BW) of Krebs-Henseleit bicarbonate solution. Group I (N-7) received B-HT 920 (specific alpha 2-adrenergic agonist, 0.6 to 58 micrograms/min), Group II (N-7) received B-HT 920+Yohimbine (300 nM in the perfusate). Group III (N-6) received vehicle only. Baseline LVP, LV +dP/dt and CFR were not significantly different among the 3 groups. During drug or vehicle administration, LVP and LV +dP/dt remained unchanged in all the groups. Coronary flow resistance increased in a dose-response fashion with a maximum increase of 22.7 +/- 3.6 (SE) mmHg/ml/min/g LV in Group I, and 10.5 +/- 2.0 mmHg/ml/min/g LV in Group II (p less than 0.02). We conclude that in the Sprague-Dawley rat heart, the physiologic effects of alpha 2-adrenoceptors are predominant in the coronary circulation but not in the myocardium itself possibly because of absence of post-synaptic alpha 2-adrenergic receptors in the rat myocardium.

Adrenergic alpha-Agonists↗
PubMed1988

Aluminium hydroxide prevents progression in experimental focal glomerular sclerosis.

To investigate the effect of phosphate binding on the progress of chronic renal disease, aluminium hydroxide was administered to rats with focal glomerular sclerosis experimentally induced by adriamycin over a period of 28 weeks (group ADR-AH). The clinical data were examined every 4 weeks and the renal histology at week 28 were compared to those in adriamycin-injected rats without aluminium hydroxide treatment (group ADR). Urinary protein excretion was less marked in group ADR-AH than in group ADR at weeks 8 and 12. Serum creatinine in group ADR started to increase at week 20 and continued to rise until week 28, while in group ADR-AH it increased less, the difference being significant. Serum phosphate was lower in group ADR-AH than in group ADR at weeks 8, 12, 24, and 28. Focal glomerular sclerosis and tubulointerstitial changes were observed in both adriamycin-injected groups regardless of aluminium hydroxide treatment at week 28, although these changes were much less severe in group ADR-AH. There were no differences in body weight and serum albumin between the two groups. We conclude that aluminium hydroxide could prevent the renal deterioration in focal glomerular sclerosis induced by adriamycin without affecting the nutritional state.

Aluminum Hydroxide↗
PubMed1987

Effect of different levels of protein intake on renal deterioration and nutritional state in experimental renal disease.

We examined the effects of various levels of dietary protein on the course of adriamycin-induced nephropathy in rats fed with high (30%), intermediately low (10%) or strictly low (5%) protein diets for 24 weeks. In the rats fed on the 30% protein diets, there were massive proteinuria, progressive increases in serum creatinine and focal glomerular sclerosis associated with severe tubulo-interstitial changes. With the 5% dietary protein, proteinuria was decreased, the levels of serum creatinine were preserved within normal ranges and renal histological changes diminished. Weight loss and hypoproteinaemia were more marked. With intermediate protein restriction (10% protein), renal function and plasma protein were preserved but body weight did not increase normally. Aggregated human immunoglobulin G, which had been intravenously injected at weeks 12 and 24, accumulated in the glomeruli more densely in rats fed on the 30% protein diet than in those fed on the 10% or 5% protein diets. We tentatively conclude that functional and histological deterioration of focal glomerular sclerosis can be prevented by appropriate restriction of dietary protein; however, severe protein restriction does aggravate nutritional states.

Animals↗
PubMed1987

Cerebral hemorrhage in patients on maintenance hemodialysis. CT analysis of 25 cases.

Site of hematoma and clinical outcome in cerebral hemorrhage were analyzed in 25 maintenance hemodialysis (HD) patients and compared with those in 27 non-HD patients. Ganglionic-thalamic hemorrhage was found in 56% of HD and 74% of non-HD patients, lobar hemorrhage in 36% and 11%, respectively. Size of hematoma, expressed as a ratio (%) of hematoma area to entire brain on CT slice, was 6.5 +/- 4.2% (mean +/- SD) in HD, being significantly larger than that of 4.7 +/- 3.5% in non-HD patients (p less than 0.05). Mortality rate was 60% in HD patients, nearly twice as much as the 33% in non-HD patients. The hematomas were significantly larger in the death cases (8.4 +/- 3.7%) than the survivors on HD (3.6 +/- 3.1%, p less than 0.005). Likewise, the fatal cases in the non-HD group had bigger hematomas (6.9 +/- 4.3%) than the non-fatal ones (3.6 +/- 2.4%, p less than 0.05). Intraventricular hemorrhage (IVH) was found in 40% of HD and 44% of non-HD patients. Hematomas were significantly larger in HD patients with IVH (9.3 +/- 3.3%) than in those without IVH (4.6 +/- 3.7, p less than 0.005). Ninety percent of the HD patients with IVH but only 42% of non-HD patients died of hemorrhage. Hypertension was equally seen in HD (76%) and non-HD patients (74%). It is concluded that in HD patients cerebral hemorrhage is more severe in terms of hematoma size, association of IVH and clinical outcome. Chronic systemic heparinization might be responsible to the severity in HD patients.

Adult↗
PubMed1987

The hemodynamic and humoral responses to tilting in diabetic patients on chronic hemodialysis treatment.

Hemodynamic and humoral responses to tilting were examined in order to elucidate the autonomic nervous function in diabetic hemodialysis patients. Eleven diabetic (DM) and eleven non-diabetic (non-DM) patients on maintenance hemodialysis treatment were involved in the experimentation, matching the age and the duration of hemodialysis. Cardiac output, blood pressure, plasma renin activity (PRA), norepinephrine (NE) and epinephrine (EP) were measured before and 5 minutes after the 45 degree tilting. By the tilting the blood pressure significantly fell in DM, whereas it rose slightly but significantly in non-DM. In both groups, however, the heart rate remained unchanged, and either cardiac index or stroke volume index decreased equally. The percentile increase in total peripheral resistance index (TPRI) was significantly smaller in DM (14.6%) than in non-DM (27.9%). There was a significant correlation between the changes in TPRI and diastolic blood pressure (r = 0.730, p less than 0.01). NE and EP increased significantly in non-DM but not in DM. Blood pressure reduced by the tilting in DM was associated with a small or equivocal response in either TPRI or plasma NE. The heart rate did not respond to the tilting in both groups. These results indicate that both sympathetic and parasympathetic nervous systems are deranged in diabetic hemodialysis patients but parasympathetic dysfunction is evident even in non-diabetic hemodialysis patients.

Adult↗
PubMed1986

Participation of the renin-angiotensin system in the captopril-induced worsening of anemia in chronic hemodialysis patients.

The study was aimed to show whether the renin-angiotensin system acts on erythropoiesis in chronic renal failure patients with hemodialysis, since captopril leads to the worsening of anemia in such patients. The average dose of captopril in 13 cases studied was 19.3 mg per day and duration of the administration was 48 days. Blood-pressure fall by captopril was accompanied with the worsening of anemia. There were significant decreases in hemoglobin (8.3%), hematocrit (7.3%), red blood cell count (7.6%) and reticulocyte count (43.7%). Angiotensin II was significantly decreased (15.7%) with significant reductions of plasma aldosterone concentration (15.2%) and angiotensin-I converting enzyme (45.7%), and with significant increases in plasma renin activity (158.6%) and in angiotensin I (238.3%). However, plasma erythropoietin concentration remained unchanged. Serum iron concentration was slightly but significantly increased after captopril. Reticulocyte count was significantly correlated with AII either before (r = 0.716, p less than 0.01) or after captopril (r = 0.658, p less than 0.05). There was significant correlation between angiotensin II and red blood cell count before captopril (r = 0.710, p less than 0.01). It is concluded from the present study that the reduction of angiotensin II by captopril might contribute to the worsening of anemia seen in chronic hemodialysis patients.

Acute Disease↗
PubMed1985

Pharmacokinetics of a new angiotensin I converting enzyme inhibitor (alacepril) after oral dosing in fasting or fed states.

The plasma concentration and urinary excretion of a newly developed angiotensin I converting enzyme inhibitor, alacepril (which is converted to captopril after absorption), were investigated in seven normal healthy subjects. Fifty milligrams of the drug was administered orally either in the fasting or in the fed state. In the fasting state, the time of maximal plasma concentration (tmax) was 1 hour for free captopril, 1.7 hours for protein-conjugated captopril, and 1.6 hours for total captopril. The biologic t1/2 of free, protein-conjugated, and total captopril was 1.9, 4.2, and 5 hours, respectively. In the fed state, neither tmax nor t1/2 changed, except that the tmax of free captopril was prolonged to 1.9 hours (P less than 0.01). Cumulative urinary excretion of free captopril at 8 hours was 35% of the drug administered in the fasting state and that of total captopril at 24 hours was 59%. These data did not differ significantly from those obtained after food intake. The biologic t1/2 of free captopril after alacepril dosing was longer than in previous studies of captopril per se. Because biologic or clinical effects have not been studied, it should be left conjectural whether alacepril is a longer-acting angiotensin I converting enzyme inhibitor. A prolonged effect of the drug can be expected by its administration after a meal.

Administration, Oral↗