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Biomedical subjects

R Takeda

Publications and source records attributed to R Takeda.

At least 379 records · Page 21Linked to original sources
PubMed1984

Circadian rhythm of plasma aldosterone and time dependent alterations of aldosterone regulators.

In order to investigate the relative contribution of ACTH, the renin angiotensin and dopaminergic system to the circadian rhythm of plasma aldosterone, hormone levels were determined at hourly intervals over a 24 h span in four supine healthy men. Blood was withdrawn under basal conditions (control), after either dexamethasone, captopril or bromocriptine++ (CB-154) administration. Plasma aldosterone rhythmicity was abolished in dexamethasone treated groups but not in captopril or CB treated groups. Time dependent alterations of aldosterone regulators were analyzed by multiple regression methods at 3 hourly intervals. These results indicate that plasma aldosterone rhythmicity is predominantly under the control of ACTH whereas the renin angiotensin or dopaminergic system plays a little role. In supine, sodium repleted states, ACTH is a potent stimulus of aldosterone at 000-0600 h and 1700-1900 h clocktime, whereas during daytime renin-angiotensin is an additional regulator.

Adrenocorticotropic Hormone↗
PubMed1984

Role of prostacyclin in blood pressure regulation and aldosterone production in conscious rabbits.

The effects of subdepressor infusion of prostacyclin (PGI2, 5.3 pmol min-1 kg-1) on arterial pressure and aldosterone production induced by angiotensin II (ANG II) were studied in conscious rabbits. Indomethacin pretreatment caused an augmented blood pressure response after ANG II infusion, which returned to near control level after concomitant infusion of a subdepressor dose of PGI2. Aldosterone production after ANG II was significantly attenuated after pretreatment with indomethacin. PGI2 infusion restored this reduced response to near control level. These results may suggest that PGI2 in the circulation could also serve to modulate the pressor and hormonal action(s) of ANG II.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Lipoprotein lipase activities in heart muscle of streptozotocin-induced diabetic rats.

Triglyceride lipase (TGL) activities in the homogenates of the rat heart muscle were studied. TGL activity per mg protein of heart muscle was the highest in heart muscle homogenate utilizing 2.1 M glycine buffer, pH 8.3 among the assays investigated. The effects of NaCl, serum and heparin on TGL activities in heart muscle homogenates indicated the characteristics of lipoprotein lipase (LPL). Twelve-hour fasting increased heart muscle LPL activity, while enzyme activities in 48 hour- and 72 hour-fasted rats were lower than those in fed rats. LPL activities in heart muscle homogenates in streptozotocin (STZ)-induced diabetic rats either 3 days or 4 weeks after STZ injection, were decreased significantly as compared with those of control rats.

Animals↗
PubMed1984

The effect of insulin-dextran complexes on the protein synthesis in the primary monolayer culture of adult rat hepatocytes.

The purpose of the present study was to investigate the mechanisms of the long-term effects of insulin on protein synthesis in rat liver parenchymal cells. Three kinds of soluble and stable insulin-dextran complexes (I: Mr 150,000; II: Mr 450,000; III: Mr 2,000,000) were prepared. The effects of insulin or insulin-dextran complexes on protein synthesis were evaluated in the primary monolayer culture of adult rat liver. To avoid the effects of serum factors, the primary monolayer culture of adult rat liver in serum free medium was established. The cultured hepatocytes well maintained the metabolic and morphological characteristics of the adult rat liver. The incorporation of [14C]-leucine into trichloroacetic acid insoluble proteins and immunoprecipitates by anti-rat albumin serum were measured in cultured hepatocytes prepared either from the control or streptozotocin-induced rats. An addition of insulin-dextran complexes to the culture medium of the hepatocytes from diabetic rats stimulated the protein synthesis as well as the native insulin. The maximal effect of insulin-dextran complex (I) on protein synthesis was comparable to native insulin. However, insulin-dextran complex (II) caused a 67% stimulation of native insulin. Insulin-dextran complexes (III) induced only a slight increase of protein synthesis. Furthermore, an addition of insulin-dextran complexes into the medium caused a more tight cellular attachment to the dish and more extensive spreading. These results favor the view that the stimulation by insulin of protein synthesis in rat hepatocytes does not require the entry of insulin into cells.

Albumins↗
PubMed1984

The characteristics of renal mineralocorticoid receptors in glycyrrhizinic acid or deoxycorticosterone-induced hypertensive rats.

The relationship between blood pressure and the characteristics of renal mineralocorticoid receptors was studied in glycyrrhizinic acid (GR) or deoxycorticosterone (DOC) induced hypertensive rats. The apparent maximum binding (Bmax) of aldosterone to renal mineralocorticoid receptors was 3.1 +/- 0.2 X 10(-13) mol/mg cytosol protein and the dissociation constant (Kd) was 1.6 +/- 0.5 nM. GR treatment reduced the concentration of cytosol mineralocorticoid receptors (Bmax) but did not affect the Kd. In unilaterally adreno-nephrectomized rats, GR induced hypertension and hypokalemia as seen in DOC treated rats. After the discontinuation of GR, blood pressure was normalized with concomitant recovery of free cytosol mineralocorticoid receptors in 14 weeks. On the contrary, in DOC treated rats, the characteristics of mineralocorticoid receptors in kidney were already normal one week after the cessation of DOC treatment. However, blood pressure remained high up to 15 weeks. These findings suggest that the persistence of hypertension after GR discontinuation might be caused by a long-standing effect of GR on renal mineralocorticoid receptor mechanisms.

Aldosterone↗
PubMed1984

Glomerular deposition and serum levels of complement control proteins in patients with IgA nephropathy.

We examined complement control proteins focusing on the role of modulating the complement activation in IgA nephropathy. Glomerular C4-binding protein (C4-bp) deposits were found in 60% of patients with IgA nephropathy, while C4 deposits were found in 30%. Glomerular deposits of beta 1H globulin (beta 1H) were found in 85% of patients with IgA nephropathy. The frequency of glomerular deposits of C4-bp tended to be higher in the group with deposits of various immunoglobulin types than in the group with deposits of IgA alone, and it increased parallel with the progression of glomerular histologic changes. The serum C4-bp level was higher in IgA nephropathy patients. No significant correlation was found between the serum level of C4-bp or beta 1H and the extent or distribution of tissue deposits of these complement control proteins. These results suggest that glomerular immune deposits in IgA nephropathy may be attributable to the activation not only of the alternative pathway but also of the classical pathway, the latter of which may take place locally in glomeruli with advanced histologic change or various immunoglobulin deposits in IgA nephropathy.

Beta-Globulins↗
PubMed1984

Plasma lipoproteins of monosodium glutamate-induced obese rats.

The plasma lipids and lipoproteins of rats developing obesity after neonatal administration of monosodium glutamate (MSG) were compared with those obtained from controls. The MSG-treated rats, in addition to being stunted and having enlarged adipose tissue stores, showed reduced body weight and food intake. These rats revealed a marked increase of plasma triglyceride and a slight but significant increase of phospholipids in both male and female. There was no significant difference in plasma cholesterol between MSG-treated rats and controls. The lipids and protein concentrations of very low density lipoprotein (VLDL: d less than 1.006 g/ml) were significantly greater in the MSG-treated rats than in the controls. There were no changes in the composition of these increased VLDL, which indicated that the number of VLDL particles was increased. Plasma triglyceride and lipids components of VLDL were significantly greater in males than in females. In spite of hypophagia, both male and female MSG-treated rats had higher plasma glucose levels than sex-matched controls. Plasma insulin level was higher in male MSG-treated rats (49.3 +/- 6.6 microU/ml [s.e.]) than in female MSG-treated rats (14.3 +/- 3.2 microU/ml) or in male control rats (34.6 +/- 6.6 microU/ml). These results suggested that hyperinsulinemia plays an important role in the increase of VLDL observed in the MSG-treated male rats.

Animals↗
PubMed1984

[Three cases of infra-optic course of the anterior cerebral artery].

Three cases of rare anomalous cerebral artery originating from internal carotid at the level of ophthalmic artery to join the anterior cerebral artery were presented. Case 1. A 32-year-old woman was admitted following subarachnoid hemorrhages. Cerebral angiography disclosed the anterior communicating artery aneurysm and the anomalous vessel originating at rt. carotid siphon to join anterior cerebral artery. Case 2. A 37-year-old woman was admitted with rt. hemiparesis and aphasia. Cerebral angiography revealed the anomalous vessel originating at rt. carotid siphon to join contralateral anterior cerebral artery. Case 3. A 22-day-old male infant with enlarged head was admitted and cerebral angiography was performed. Anomalous vessel originating from internal carotid at the level of ophthalmic artery joined to the azygos anterior cerebral artery. There were only sixteen reported cases of this anomaly including our three cases. Seven aneurysms were associated in six cases, in which four were located in anterior communicating system. The fact that among the cases of this anomaly, ophthalmic artery used to not have normal stem but be fed from middle meningeal or middle cerebral artery suggested that the anomalous vessel had the common stem with ophthalmic artery at certain embryonic stage. These considerations led us to the conclusion that this anomalous vessel might originate from the remnant of anastomotic loop between primitive dorsal and ventral ophthalmic artery.

Adult↗
PubMed1984

[Evaluation of septal hypertrophy and wall dynamics by biventricular cineangiography and endomyocardial biopsy].

To clarify clinically the pathogenesis of septal hypertrophy in terms of its morphology and wall dynamics, simultaneous biventricular cineangiography (BVG) and endomyocardial biopsy of the left ventricle were performed for patients with left ventricular hypertrophy. The patients were categorized in four groups according to their clinical and BVG findings; 1) 24 normal control subjects (C), 2) 39 patients with hypertension and symmetrical septal hypertrophy (SH-HT), 3) 17 patients with hypertension and asymmetrical septal hypertrophy characterized by the ratio (IVS/PW) greater than or equal to 1.3 by BVG, and 4) 25 patients with hypertrophic cardiomyopathy (HCM). The BVG's configuration of the septum in SH-HT showed a normal form of septal hypertrophy (NH form) essentially similar to that of the control subjects (N form), except for septal thickness increases of more than 10 mm. In HCM, a triangle or shell (TS) form or spindle (S) form of the septum was demonstrated by BVG. The TS form was characterized by straight or convex thickening of the septum from its center to its base toward the left ventricle. The S form was characterized by convex thickening localized to the central part and a relatively thin base. However, the configuration in ASH-HT was either the NH form (7 cases) or the TS or S form (10 cases). The configuration in ASH-HT with the NH form was not distinguishable from that of SH-HT, nor was the configuration in ASH-HT with the TS or S form distinguishable from that of HCM. Systolic thickening (%) of the septum and systolic shortening (%) of the septal length decreased significantly in this order: C, SH-HT, ASH-HT with the NH form, and ASH-HT with the TS or S form. Those of HCM were similar to those of ASH-HT with the TS or S form. In the cases of the N or NH form, there was a negative correlation between systolic thickening (%) and thickness of the septum in diastole. In cases with the TS or S form, systolic thickening (%) was not affected by the thickness of the septum in diastole, and a lower value was observed in all cases. Histological studies of endomyocardial biopsies revealed a positive correlation between the transverse diameters of the myocytes and the total systemic peripheral resistance (TSPR) in 25 patients with SH-HT. In 12 patients with HCM, there was no correlation, and severe hypertrophy of the myocytes was observed despite a lower TSPR.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗