1,721,013 research outputs found
Preface : Problems in the diagnosis and treatment of primary aldosteronism(Proceeding of the 3rd Conference on Adrenal Venous Sampling)
No full textPreface for proceedings of the conference on adrenal venous sampling(Proceedings of the Conference on Adrenal Venous Sampling)
No full textThe future problem of adrenal venous sampling(Significance of ACTH-loaded adrenal venous sampling in adrenal primary aldosteronism,Proceedings of the 2nd Conference on Adrenal Venous Sampling)
No full textImmunohistochemical Study of the Interrelation Between the Expression of Nitric Oxide Synthase (NOS) in the Kidney and the Renin-Angiotensin System in Rats
No full textIt has become increasingly evident that ntiric oxide (NO) plays an improtant role in the regulation of renal hemodynamics and tubular function based on interactions with the renin-angiotensin system. NO synthase (NOS) produces NO and has recently been demonstrated to be present in the kidney. We determined the changes in intrarenal NOS immunoreactivity relevant to the changes in systemic blood pressure and the renin-angiotensin system. Rats received 4 different types of treatment, and kidney sections were immunohistochemically stained for renin, NOS-I, and NOS-III. Plasma renin activity (PRA) and the angiotensin II (AngII) concentration were determined by radioimmunoassay. In the low-salt group, PRA, plasma Ang II, and the number of renin and NOS-I positively stained areas in the juxtaglomerular apparatus (JGA) were all increased, while blood pressure (BP) and NOS-III in the glomerular capillaries were un-changed. In the desoxycorticosterone acetate (DOCA)-salt group, in contrast, BP was elevated, but PRA, plasma Ang II and all immunohistochemical parameters were decreased. In the Ang II infusion group, BP, plasma Ang II, and the number of NOS-I positive glomeruli were increased, while PRA and renin staining were decreased. Administration of the Ang II type 1 receptor (AT1) antagonist TCV-116 significantly increased PRA, plasma AngII, and the number of renin-positive glomeruli. However, BP, and NOS-I and NOS-III staining did not differ. These results indicate that NOS-I in the macula densa changes in parallel with plasma Ang II but not renin or systemic BP
Vasculo-protective Effect of Insulin Sensitizing Thiazolidine Derivative : Pioglitazone in Vascular Neo-intimal Formation
No full textIt has been demonstrated that thiazolidine, a novel insulin sensitizing agent, has inhibitory effects on the growth of cultured vascular smooth muscle cells (VSMC) in vitro, in addition to its effects on glucose and lipid metabolism. This study was undertaken to examine the in vivo effects of the thiazolidine compound pioglitazone (PIO) on carotid neo-intimal thickening after endothelial injury in Wistar rats. PIO treatment (3mg/kg/day, for 1 week before and 2 weeks after endothelial injury) remarkably decreased neo-intimal cross-section areas (63.8±4.9×10^3μm^2 vs 196±7.6×10^3μm^2 in controls, p<0.05), bromodeoxyuridine uptake in the neo-intima, (as a marker of DNA synthesis), and expression of EIIIA fibronectin as a marker of the synthetic phenotype of VSMC. These results suggest that PIO has direct vasculo-protective effects in acute vascular injury in vivo by inhibition of VSMC proliferation and through phenotypic change of VSMC
Differential Effects of Angiotensin II on the Secretion and mRNA Expression of Leptin in Mouse Cultured Brown and White Adipocytes
No full textAlthough it has been implied that the renin/angiotensin system is deeply involved in the regulation of adipocyte function, the details of the role of the system remain to be elucidated. In the present study, we investigated the effects of angiotensin II (Ang II) on leptin secretion and leptin mRNA expression in the adipocytes of brown adipose tissues (BAT) and white adipose tissues (WAT) of mice. Mature adipocytes were prepared by collagenase treatment and culture in DMEM containing 10% fetal bovine serum and 4 nM insulin. Cultured adipocytes were incubated in the medium containing Ang II (10^<-9>～10^<-11>M),the AT1-selective antagonist Losartan (10^<-6>～10^<-8>M), or the AT2-selective antagonist PD 123319 (10^<-6>～10^<-8>M) alone, or a combination of Ang II and antagonist. After incubation for 24 hr, the leptin concentration in the medium was determined by radioimmunoassay. Leptin mRNA expression in the cells was determined by RT-PCR. Ang II increased and decreased leptin secretion by BAT and WAT, respectively, in a dose-dependent manner. Ang II did not affect leptin mRNA expression in BAT, but it significantly decreased leptin mRNA expression in WAT. The effect of Ang II on leptin secretion by BAT was significantly suppressed by PD123319 and the effect of Ang II on leptin secretion and leptin mRNA expression in WAT was suppressed by Losartan. These results suggested that Ang II is involved in the regulation of adipose tissue function through its effects on leptin synthesis and/or secretion. In addition, since the effects in BAT and WAT were mediated through different Ang II receptor subtypes, AT2 in BAT and AT1 in WAT, it is suggested that the receptor subtype is of great biological significance in the action of Ang II on adipocytes as well as on the cardiovascular system
Selective Adrenal Venous Sampling with ACTH Infusion(Proceedings of the Conference on Adrenal Venous Sampling)
No full textACTH-stimulated adrenal venous sampling (ACTH-AVS) has been reported to improve specificity and sensitivity of the procedure in the diagnosis of primary aldosteronism (PA). The method, diagnostic criteria, and the significance of the procedure however remain to be established. In the present study, we investigated the significance of the ACTH-AVS in 10 patients in which PA was biochemically and/or morphologically suggested. ACTH-AVS was performed by a left inguinal catheterization. Blood samples were obtained from the inferior caval vein and bilateral adrenal veins before and 60 min after infusion of ACTH (synthetic 1-24 ACTH, 125μg/100ml/hr). Plasma aldosterone (Aldo), cortisol (C), and their ratio Aldo/C were determined. Unilateral adrenalectomy was performed in 6 patients with evident laterality of the adrenal lesion and the diagnosis was confirmed pathologically. By contrast, adrenal surgery was not indicated in 4 patients in whom laterality of the lesion was inconclusive. Since ACTH stimulation increased plasma Aldo both in the adenoma and contra-lateral sides of the adrenal in those 6 patients with PA, no significant increase was achieved in the higher to lower Aldo ratio. In addition, since the increment of C was larger than that of Aldo after ACTH stimulation, Aldo/C ratio showed a decrease in most of the patients. ACTH stimulation increased Aldo in both sides of the adrenal with no significant enhancement of the ratio in the inconclusive 4 patients. The difference of Aldo between higher and lower sides however exceeded 1000 ng/dl in those 6 patients with PA, while it was less than 1,000 ng/dl in the inconclusive 4 patients. These results suggest that ACTH-AVS does not exaggerate the higher to lower Aldo ratio nor Aldo/C ratio but the deference of Aldo between the higher and lower sides. Further studies are required to establish the significance of ACTH-AVS
Hypertension in Women : Diagnosis and Treatment
No full textThere is no gender difference in the principle of the diagnosis and treatment of hypertension. Hypertension in women is however characterized by its causes of hypertension, relation to obesity, and influences of pregnancy and menopause. Endocrine hypertension such as primary aldosteronism and Cushing' s syndrome is much more common in women than men. Obesity could be more closely correlated to blood pressure increase in women. Special care should be taken in the treatment of hypertension of the pregnant women. Those commonly utilized agents such as angiotensin converting enzyme inhibitors and Ca channel antagonists are basically contraindicated. Difficulties in controlling hypertension are often experienced with hydralazine and a-methyl dopa as the recommended first line agents. Incidence of hypertension is significantly increased in the postmenopausal women. Changes in life style and social circumstance are involved in the development of hypertension in addition to the estrogen deficiency as the major endocrine background. The postmenopausal hypertension has an increasing impact on the quality of life in women because of the significant elongation of the life span. Antihypertensive agents as well as life style modification considering the pathophysiology are needed. Hormone replacement therapy is not recommended solely for the purpose of blood pressure control. Close interrelationship are warranted between internists and obstetricians/gynecologists in any aspects of hypertension in women
Pathophysiologic Significance of Hormones in Hypertension
No full text東京女子医科大学学会第284回例会 平成2年11日8日 東京女子医科大学臨床講堂
Analysis of the Sites of Action of Nitric Oxide (NO) in the Central Nervous System : Its Relationship to Central Regulation of Cardiovascular Function
No full textAlthough nitric oxide (NO) is involved in regulation of the cardiovascular, neuroendocrine, and autonomic system via the central nervous system, its specific sites of action in the brain have not been determined. To clarify the effect of NO in the central nervous system, we injected NO-releasing compounds and NOS inhibitors into the brains of conscious, freely moving rats and measured its effect on mean arterial blood pressure (MAP) and heart rate (HR), as well as on expression of c-fos mRNA, an immediate-early gene used to identify neurons affected by environmental stimuli, and NADPH-diaphorase, an indicator of NOS activity. Intracerebroventricular (icv) administration of the NO donors, 1μmol of sodium nitroprusside (SNP), and NOC-18, caused a significant fall in MAP and HR. In contrast, the NOS inhibitor, N^G-nitro-L-arginine methyl ester (L-NAME), induced a significant rise in MAP when administered either intravenously or intraventricularly. The centrally administered NO donors SNP and NOC-18 induced c-fos mRNA expression in several regions of the brain primarily involved in the baroreceptor response, as well as regions of the brain involved in the integration of autonomic, neuroendocrine, and behavioral responses. Most of the areas that expressed c-fos also stained for NADPH-d. These results suggest that NO acts directly in the brain to reduce the systemic blood pressure, and that the endogenous NO pathway may play a role in cardiovascular and autonomic regulation by modulating neuronal activity in discrete regions of the brain
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