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Biomedical subjects

R Takeda

Publications and source records attributed to R Takeda.

At least 145 records · Page 8Linked to original sources
PubMed1993

Functional limitation of recruitable collaterals in human subjects--ST segment deviation on intracoronary electrocardiogram during transient coronary occlusion induced by balloon inflation.

Three patients showed ST elevation on precordial electrocardiogram and ST depression on intracoronary electrocardiogram during angioplasty of the left anterior descending coronary arteries (LAD). While none of the patients had spontaneously visible collaterals, all showed transient recruitable collaterals to the LAD. No evident collaterals into the diagonal branches were observed. Possibly, if the intracoronary electrocardiogram represents the potential changes of the epicardial surface in the vicinity of the guidewire tip, then endocardial ischemia may have developed even though epicardial ischemia was not observed, due to relatively sufficient blood flow through the recruitable collaterals to the LAD. ST elevation on the precordial electrocardiogram may have represented epicardial and endocardial ischemia of the diagonal branches, where the recruitable collaterals could not protect against transmural ischemia. These phenomena suggests that the recruitable collaterals are functionally limited during acute coronary occlusion, even though the collaterals are well developed.

Aged↗
PubMed1993

Cellular effects of isoflurane on bulbar respiratory neurons in decerebrate cats.

Effects of isoflurane on the membrane potential trajectory and synaptic activity in bulbar respiratory neurons were investigated in decerebrate, vagotomized and artificially ventilated cats. A 2-min inhalation of 1.6% end-tidal concentration of isoflurane produced depolarization of the membrane in 10 out of 18 inspiratory, 8 out of 15 post-inspiratory and 5 out of 12 expiratory neurons and hyperpolarization in the rest of the population recorded in the ventral respiratory group. In both depolarized and hyperpolarized cells, periodically occurring excitatory and inhibitory synaptic waves were decreased, and input resistance was increased. Concomitantly, isoflurane reduced the excitatory and inhibitory postsynaptic potentials evoked by electrical stimulation of the vagus nerve, superior laryngeal nerve and cervical spinal cord. The effects of isoflurane on membrane potential and input resistance became negligible when excitatory and inhibitory synaptic potentials were suppressed by iontophoretically applied tetrodotoxin. The present results suggest that the respiratory neuronal responses induced by isoflurane are attributed mainly to the decrease of excitatory and inhibitory synaptic interactions in the bulbar respiratory network of neurons.

Action Potentials↗
PubMed1993

Reversible left ventricular diastolic dysfunction resulting from frequent supraventricular tachycardia.

In two patients with frequent supraventricular tachycardia, echocardiograms revealed remarkable left ventricular systolic and diastolic dysfunction, associated with an absence of left ventricular filling during the early diastolic phase. This dysfunction was detected during normal sinus rhythm as well as tachycardia. By treatment with propafenone, both patients showed dramatic and rapid improvement of symptoms and the left ventricular dysfunction. Left ventricular diastolic dysfunction as well as systolic dysfunction were detected in patients with supraventricular tachycardia, suggesting that frequent supraventricular tachycardia results in severe left ventricular diastolic dysfunction which is reversible after control of the tachycardia.

Aged↗
PubMed1993

[Endocrine hypertension].

Endocrine Hypertension, is, in a narrow sense, defined as adrenal hypertension, including mainly pheochromocytoma, Cushing's syndrome, a syndrome of primary aldosteronism and it's related mineralocorticoid excess disorders. In memory of a great contribution to hypertensiology by the late Prof. Murakami, who was the first author to write on pheochromocytoma in Japan, this paper is dedicated to reviewing the current status of adrenal hypertension in Japan from the epidemiological viewpoint, putting emphasis upon the clinical characteristics of aged patients with adrenal hypertension. Secondly, some topics in the research field of each adrenal hypertension are briefly introduced. Thirdly, our recent data are presented, showing 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) mRNA expression in resistance vessels and decreased 11 beta-HSD activities in vessels in SHR which supports the hypothesis that there might exist a subtype identified as partial impairment of 11 beta-HSD in patients with essential hypertension.

17-Hydroxysteroid Dehydrogenases↗
PubMed1993

[Indications of G-CSF in patients with drug-induced agranulocytosis].

Bone marrow findings at the onset of disease were analyzed in five patients with drug-induced agranulocytosis to detect simple indices for a determination of the indications G-CSF therapy. Two patients showed severe marrow hypoplasia, extremely low ME ratio and complete absence of myelocytes or more mature neutrophils in their bone marrow. In these cases, the periods for recovery to 500 or more peripheral neutrophils per microliter were 5 and 9 days in a G-CSF-treated patient and a non-treated patient, respectively. On the other hand, the bone marrow of other three patients revealed normal or slightly high cellularity, moderately low ME ratio and appearance of myelocytes and more mature neutrophils. In the latter cases, the periods for recovery to 500 or more peripheral neutrophils were 3 days in all cases, regardless of whether G-CSF was administered or not. These findings suggest that G-CSF should be administered to drug-induced agranulocytic patients with severe marrow hypoplasia, extremely low ME ratio and absence of marrow neutrophilic cells.

Adult↗
PubMed1993

[Long-term maintenance of platelets by IFN alpha-2b in a case of chronic idiopathic thrombocytopenic purpura refractory to prednisolone therapy].

A 63-year-old female with chronic idiopathic thrombocytopenic purpura refractory to prednisolone therapy was treated with interferon alpha-2b (IFN alpha-2b). Initially, the patient received 2 courses of short-course therapy in which 1.5 million IU and IFN alpha-2b was subcutaneously injected 3 times a week every other day for 4 weeks. During the first course, the platelet count rose from 1.0 x 10(4)/microliters to 12.4 x 10(4)/microliters 3 weeks after the beginning of the therapy, but the effect was transient. In the second course the platelet-increasing effect was lower than that in the first course. Then, intermittent injections of 3 million IU of IFN alpha-2b once a week were subsequently begun. Consequently, the patient's platelet count has been maintained at 5 to 9 x 10(4)/microliters for more than 19 months since the beginning of intermittent IFN alpha-2b therapy.

Drug Resistance↗
PubMed1992

Serum apolipoproteins in heterozygous familial hypercholesterolemia.

In order to characterize the abnormalities of the lipoprotein profile in familial hypercholesterolemia (FH), serum apolipoprotein AI, AII, B, CII, CIII, and E levels were determined by the turbidimetric immunoassay in 48 patients with heterozygous FH. Apolipoprotein B levels in FH were about 2.5 fold higher (203 +/- 48 mg/dl, mean +/- S.D.) than the 30 age-matched normolipidemic control subjects (84 +/- 13 mg/dl). Significant increments of apolipoprotein CII, CIII, and E levels were observed in FH (4.6 +/- 1.6, 11.0 +/- 3.6 and 6.4 +/- 1.7 mg/dl, respectively) as compared with those in normal subjects (3.0 +/- 0.9, 7.7 +/- 1.6 and 4.5 +/- 1.1 mg/dl, respectively). Apolipoprotein AI and AII levels in FH were 130 +/- 27 and 32 +/- 6.0 mg/dl, respectively, which were not significantly different from the levels in normal subjects (131 +/- 18 and 31 +/- 5.4 mg/dl, respectively). The ratio of low density lipoprotein (LDL) cholesterol to apolipoprotein B was significantly higher in FH (1.3 +/- 0.3) than that in normal subjects (1.2 +/- 0.1). This indicates that the LDL of FH was cholesterol-rich in comparison with that of normal subjects. The ratio of high density lipoprotein (HDL) cholesterol to apolipoprotein AI in FH (0.34 +/- 0.07) was significantly lower than that in normal subjects (0.39 +/- 0.05). This difference might possibly be produced by an abnormal HDL metabolism of FH patients, a topic which remains to be elucidated by further investigation.

Adult↗
PubMed1992

[11 beta-hydroxysteroid dehydrogenase and steroid receptors].

11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD), as its name implies, is the enzyme responsible for the conversion of cortisol to cortisone, and of corticosterone to 11-dehydrocorticosterone. Ulick et al. reported the detailed investigation of a patient with the syndrome of apparent mineralocorticoid excess (AME), who had the stigmata of florid hyperaldosteronism but low normal or suppressed levels of renin and aldosterone. Such patients show marked abnormalities of cortisol metabolism. From a series of studies, the consensus grew that AME reflects the absence, or very low activity, of 11 beta-HSD in the kidney of affected patients. In addition to providing a framework for understanding the pathogenesis of AME, these studies prompted a re-evaluation of other areas of steroid in the kidney. Glycyrrhetinic acid, the active principle of liquorice and carbenoxolone, exerted its mineralocorticoid action not by a direct effect on mineralocorticoid receptors but by inhibiting renal 11 beta-HSD, thus producing a mild, drug-induced form of AME. Recently Monder et al. reported the cloning and expression of rat and human cDNA encoding corticosteroid 11 beta-dehydrogenase. The physiological role of 11 beta-HSD in conferring aldosterone-selectivity on otherwise non-selective type I receptors has been focused using the genetic method in addition to the biological ones.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1992

Cardiac characteristics and postoperative courses in Cushing's syndrome.

To assess the cardiac characteristics and postoperative courses in patients with Cushing's syndrome, electrocardiography and echocardiography were performed to study 12 consecutive, unselected patients, and results were compared with those of essential hypertension and primary aldosteronism. Eleven patients had hypertension and 7 had diabetes mellitus. Before adrenalectomy, common electrocardiographic abnormalities consisted of high-voltage QRS complexes (10 patients) and negative T waves (7 patients). Echocardiograms showed left ventricular hypertrophy in 9 patients, and all the patients had evidence of asymmetric septal hypertrophy. In patients with left ventricular hypertrophy, the thickness of the interventricular septum ranged from 16 to 32 mm, whereas the ratio of the thickness of interventricular septum to that of the posterior wall ranged from 1.33 to 2.67. The interventricular septum in Cushing's syndrome was extremely thicker and asymmetric septal hypertrophy occurred more often than essential hypertension and primary aldosteronism. Nine patients could be followed up after operation. In these patients abnormal electrocardiographic findings had normalized, the thickness of interventricular septum had decreased and asymmetric septal hypertrophy had disappeared except in 1 patient. The reason why left ventricular hypertrophy in Cushing's syndrome is severe is still unknown. Because left ventricular hypertrophy is more severe and the frequency of asymmetric septal hypertrophy much greater in Cushing's syndrome than in essential and other secondary hypertension, it is thought that not only increased aortic pressure but excessive plasma cortisol may be etiologic factors in the progression of left ventricular hypertrophy in Cushing's syndrome.

Adrenal Gland Neoplasms↗
PubMed1992

Endothelin-1 release from the mesenteric arteries of cyclosporine-treated rats.

The release of endothelin-1 from mesenteric arteries from cyclosporine-treated rats was measured by a specific enzyme immunoassay after purification of the perfusate on an immunoaffinity column. Mesenteric arteries from cyclosporine-treated rats (25 mg/kg per day for 6 weeks) released a significantly larger amount of endothelin-1 than arteries from vehicle-treated control rats (P less than 0.05). Serum creatinine levels were not significantly different in the two groups. These findings indicate that cyclosporine is a potential inducer of endothelin release from the mesenteric artery.

Animals↗
PubMed1992

[Long-term treatment of acromegaly and gigantism with octreotide (SMS 201-995)].

Twenty-one patients with active acromegaly and two patients with pituitary gigantism were treated with the long-acting somatostatin analogue octreotide (100-600 micrograms/day, sc, two or three times daily or 300-1500 micrograms daily by intermittent sc infusion) for 9-63 months. There was rapid clinical improvement. The fasting plasma GH levels were significantly suppressed (less than 50% of the values before treatment) in 17 patients and were normalized (less than 5 ng/ml) in 6 patients (27.3%). Plasma IGF-I levels were lowered by 50% and were normalized in 7 out of 18 cases. The effect of octreotide on pituitary tumor size was evaluated in 13 patients. In 4 cases, the shrinkage of the pituitary tumor was detected by computed tomographic scans and/or magnetic resonance imaging studies. The drug was generally well tolerated. However, there were probably newly formed gallstones in two patients during the therapy. Our study suggests that octreotide is an effective and relatively safe new approach for treating active acromegaly and gigantism.

Acromegaly↗