Search PubMed⌕ Search

Biomedical subjects

R Takeda

Publications and source records attributed to R Takeda.

At least 289 records · Page 16Linked to original sources
PubMed1987

A new low density lipoprotein apheresis system using two dextran sulfate cellulose columns in an automated column regenerating unit (LDL continuous apheresis).

We describe a new low density lipoprotein (LDL) apheresis system using dextran sulfate cellulose column in an automated column regenerating unit (LDL continuous apheresis). Two columns containing 150 ml of dextran sulfate cellulose were used, and the whole extracorporeal circulation was about 400 ml in volume. After 600 ml of plasma was adsorbed into the first column, the second column was used as an adsorbent and meanwhile the first column was regenerated. Thus, the 2 columns were used alternately without losing the potency of the columns. As the apparatus was automatically controlled by a computerized unit, no extra manipulation is necessary compared with the conventional single-column method. By treating 4-5 liters of plasma, non-high density lipoprotein (HDL)-cholesterol levels decreased by 63-71%, and HDL-cholesterol levels remained unchanged. Thus, this new method of LDL apheresis can safely reduce LDL-cholesterol to any desired level and will be applicable for the treatment of child and adult family hypercholesterolemic patients with severe coronary heart disease.

Adult↗
PubMed1987

Glycyrrhizic acid and its hydrolysate as mineralocorticoid agonist.

Mineralocorticoid activity of glycyrrhetinic acid (GR) was studied in vivo (electrical potential difference in rat rectum) and in vitro (brush border Mg2+-HCO3- ATPase in rat small intestine, kidney cytosol binding of GR with and without RU-28362, anti-glucocorticoid compound) in order to clarify the mechanism of mineralocorticoid-like activity of GR. Scatchard analysis of [3H]aldosterone showed that Kd of higher affinity site (type I) 6.0 X 10(-9) M, Bmax 1.0 X 10(-14) mol/mg protein, and Kd of lower affinity site (type II) 1.6 X 10(-7) M, Bmax 7.5 X 10(-14) mol/mg protein. GR competed for [3H]aldosterone binding sites in kidney cytosol at the concentration of 10(4) times as that of unlabeled aldosterone. RU-28362 displaced aldosterone binding curve, whereas GR binding kinetic was not affected by this compound. Adrenalectomy caused a significant fall in brush border Mg2+-HCO3- ATPase activity (75% reduction compared with the initial level) which was not restored by GR administration. Electrical potential differences in the adrenalecomized rats were significantly lower than those in the control rats, which did not increase after GR administration.

Adrenalectomy↗
PubMed1987

Effect of ketoconazole, etomidate and other inhibitors of steroidogenesis on cytochrome P-450sccII-catalyzed reactions.

The effects of a variety of certain inhibitors of adrenal steroidogenesis have been studied on the reconstituted C21-steroid 17 alpha-hydroxylase-17,20-lyase system, whose protein components, the enzyme 17 alpha-hydroxylase-17,20-lyase(P-450sccII) and its reductase, are extensively purified from pig testis microsomes. We found: (1) Ketoconazole (cis-1-acetyl-4-[4-((2-(2,4-dichlorophenyl)-2-(1H-imidazole-1- ylmethyl-1,3-dioxalan-4-ol)methoxy)phenyl] piperazine and Etomidate(R-(+)-ethyl-[1-(a-methyl-benzyl)-indol-5-carboxylatel), inhibited cleavage of 17 alpha-hydroxy progesterone at the 17,20-bond to give androstenedione in a dose-dependent fashion. (2) Some other inhibitors of steroidogenesis, Metyrapone (2-methyl-1.2di-3-pyridyl-1-propanone), Trilostane (4,5-epoxy-17-hydroxy-3-oxo androstane-2-carbonitrile),o,p'DDD (1-(O-chlorophenyl)-1-(p-chlorophenyl)2,2-dichloroethane) and Aminoglutethimide (p-(alpha-aminopheny)-alpha-ethylglutaramide) did not inhibit the same 17,20-lyase system. (3) All of the above listed inhibitors, over a wide variety of concentration ranges, had no significant effect on the 17 alpha-hydroxylation of 11 beta-hydroxyprogesterone, which had been shown to be catalyzed by the same P-450sccII. (4) NADPH:P-450 reductase was not inhibited by all of the above listed inhibitors.

Animals↗
PubMed1987

Effects of CS-514 on serum lipoprotein lipid and apolipoprotein levels in patients with familial hypercholesterolemia.

Effects of CS-514, a new competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on serum lipoprotein lipid and apolipoprotein levels were studied in 13 heterozygous patients with familial hypercholesterolemia. Treatment with 10 mg of CS-514 twice daily reduced total serum cholesterol, low-density lipoprotein (LDL), and intermediate-density lipoprotein (IDL) cholesterol levels by 25%, 33%, and 33%, respectively, and increased high-density lipoprotein (HDL) cholesterol levels by 15%. Apolipoprotein B, E, and C-II levels decreased by 24%, 20%, and 19%, and apolipoproteins A-I and A-II levels increased by 10% and 7%, respectively. One patient showed abnormally high levels of SGOT, SGPT, and serum alkaline phosphatase, which returned to normal levels immediately after the cessation of CS-514. No other adverse effects were observed. Thus, CS-514 reduces atherogenic lipoproteins and apolipoprotein B, and increases HDL and apolipoprotein A-I and A-II, and appears to be a useful drug for heterozygous familial hypercholesterolemia.

Adult↗
PubMed1987

Human atrial natriuretic polypeptide during escape from mineralocorticoid excess in man.

1. Plasma concentrations of human alpha-atrial natriuretic polypeptide (h-alpha ANP) during escape from the effects of mineralocorticoid excess were determined in six healthy volunteers. 2. Escape, as indicated by an abrupt increase in sodium excretion on the third to sixth day of 9 alpha-fludrocortisone acetate administration (0.6 mg/day), was observed in all subjects. 3. The mean plasma h-alpha ANP level was 30.9 +/- SEM 8.8 pmol/l on the control day; it increased exponentially in response to 9 alpha-fludrocortisone acetate administration, reached a significant level (114.0 +/- 22.4 pmol/l, P less than 0.05) on the day before escape and remained elevated during escape. 4. The 24 h creatinine clearance and blood pressure did not change significantly before the escape. Plasma h-alpha ANP increased markedly when the cumulative sodium balance exceeded 220 mmol. 5. These results suggest that h-alpha ANP may play a contributory role in natriuresis and diuresis after mineralocorticoid excess.

Adult↗
PubMed1987

The renal, cardiovascular and hormonal actions of human atrial natriuretic peptide in man; effects of indomethacin.

The renal, cardiovascular and hormonal effects of intravenous infusion of alpha-human atrial natriuretic polypeptides (alpha-hANP) at the concentrations of 0.0125, 0.025, 0.05, 0.1 microgram kg-1 min-1 for 20 min was studied in six male volunteers before and after indomethacin administration (150 mg day-1, three times daily for 3 days). Dose-dependent diuresis and natriuresis were observed in all subjects between the concentrations of 0.025 and 0.1 microgram kg-1 min-1, which were not influenced by indomethacin. Diastolic blood pressure decreased significantly (P less than 0.05) at the higher dose (0.05 microgram kg-1 min-1) of alpha-hANP, which was attenuated by indomethacin pretreatment. The plasma concentration of the immunoreactive alpha-hANP was 73.7 +/- 25 pg ml-1 on the control in subjects taking 200 mEq day-1 of sodium, and significant diuresis occurred when plasma concentration reached approximately 330.5 +/- 74.4 pg ml-1. alpha-hANP infusion caused a dose-dependent increase in cyclic GMP, no significant changes in plasma aldosterone and 18-hydroxycorticosterone, which were not influenced by indomethacin pretreatment. Plasma renin did not change in response to alpha-hANP infusion, which was significantly decreased (P less than 0.05) after indomethacin pretreatment. These results support that the renal effects of alpha-hANP may be exerted by prostaglandin-independent mechanisms. The renal effects occur at lower doses, and cardiovascular changes occur at higher doses of alpha-hANP.

18-Hydroxycorticosterone↗
PubMed1987

Pancreatic vagal nerve is receptive to somatostatin in rats.

To investigate whether somatostatin, one of the pancreatic islet hormones, influences the afferent firing activity of the vagus innervating the pancreas and whether there is any relevant morphological basis for the electrophysiological event, cyclic somatostatin-14 was injected into the rat pancreatic artery. The somatostatin injection at a physiological (0.61 pmol) or a pharmacological (3.05 pmol) dose significantly increased the afferent firing discharge rate of the pancreatic vagus in rats anesthetized with urethan and chloralose. The present histological examination disclosed a glomuslike neurovascular body in the rat peripancreatic sinusoidal vein. The body included many small corpuscles, and the corpuscle contained a structure like the afferent nerve ending. The immunohistochemical study revealed that the structure preferentially bound exogenous somatostatin. These electrophysiological and histological findings suggest that the vagal pancreatic nerve is receptive to somatostatin and that there exists a local neural monitoring system for somatostatin secreted from the islets.

Afferent Pathways↗
PubMed1987

Effects of corticotropin-releasing factor (CRF) on aldosterone and 18-hydroxycorticosterone in essential hypertension and primary aldosteronism.

The effects of ovine corticotropin releasing factor (o-CRF) on plasma aldosterone, 18-OH-corticosterone (18-OHB), plasma adrenocorticotropin (ACTH) and cortisol were determined in eight patients with primary aldosteronism, six with aldosterone-producing adenoma (APA) and two with idiopathic hyperaldosteronism (IHA). The results were compared with those in six normal subjects and eleven patients with essential hypertension (EHT, 5 with low renin and 6 with normal renin). In patients with APA, the peak plasma aldosterone and 18-OHB responses to 100 micrograms iv of o-CRF (226% and 113% increase from baseline, respectively) were greater than those in EHT and normal subjects. The net integrated aldosterone and 18-OHB responses (840 +/- 156, and 419 +/- 121 ng/dl.hr, respectively) were also significantly greater (p less than 0.01) in APA than those in normals and EHT. In two patients with IHA, both the peak and net integrated aldosterone response were smaller than those in APA, in spite of nearly identical plasma ACTH and cortisol responses. These results suggest that augmented responses of mineralocorticoids to o-CRF may be characteristic of aldosteronism due to APA, mediated by CRF-induced ACTH, and possibly other proopiomelanocortin (POMC)-derived peptides.

18-Hydroxycorticosterone↗
PubMed1987

Long-term effects of converting enzyme inhibitors on split renal function in renovascular hypertension.

Long-term effects of angiotensin converting enzyme inhibitors on split renal function were studied using a noninvasive radioisotopic method in five patients with renovascular hypertension. In the stenotic side the glomerular filtration rate which acutely decreased following captopril, tended to return toward pretreatment levels on prolonged captopril administration (up to 2 years), while the value remained unchanged in the nonstenotic side of the kidney. Effective renal plasma flow increased in both sides. During long-term captopril treatment, there were no significant changes in serum creatinine, sodium, potassium, and blood pressure control was maintained at the same level in an acute period. These results suggest that the glomerular filtration in the stenotic kidney of renovascular hypertension, which was acutely reduced, will not further deteriorate, but will increase after prolonged captopril treatment.

Adult↗
PubMed1987

[Basic and clinical evaluation of a new assay procedure "SCC RIABEAD" for estimation of squamous cell carcinoma related antigen].

We examined the efficacy of a new commercial assay procedure (SCC RIABEAD) for estimation of squamous cell carcinoma related antigen (SCC). Intraassay and interassay variance were 4.0-14.6% and 4.6-17.0% respectively. Recovery and dilution tests gave satisfactory results. The normal range was under the level of 1.63 ng/ml. The patients with uterine cervical cancer or squamous cell carcinoma of the lung showed high positive rates. The values of SCC measured by SCC RIABEAD were well-correlated to those by SCC RIAKIT. However, SCC RIABEAD showed lower values in low SCC level and higher values in high SCC level than SCC RIAKIT.

Adult↗