摘要:

Nonspecific aortoarteritis is the commonest cause of renovascular hypertension (RVH) accounting for 87% of the patients in the present study. We compared the clinical and radiographic features and outcome in children (n = 16) and adult (n = 24) patients with aortoarteritis. Children have a shorter duration of disease and present more commonly with constitutional symptoms. All the patients were hypertensive; however, malignant hypertension and hypertensive encephalopathy were more common in children. Abdominal bruit and asymmetry of pulses were present only in 75 and 35% of the patients, respectively. Asymmetric kidney size on ultrasound was present in 15 of 24 adults, whereas 9 of 16 children had equal sized kidneys. Captopril renography had a better sensitivity for detection of RVH in children (13 of 16 in children vs. 12 of 24 in adults showing positive results). On intra-arterial digital substraction angiography, abdominal aortic involvement was invariable, whereas the thoracic aorta was involved less frequently in both age groups. Angiographic scores for the severity of vascular involvement was significantly lesser in children (6.87 ± 4.8) as compared to adults (11.32 ± 4.5). Thirteen of the 15 children were found suitable for revascularization, whereas 12 of 24 adults were not considered for revascularization as their kidneys were small and contributed to less than 10% of total function. Six of the adult patients underwent nephrectomy for the control of blood pressure. Results of angioplasty were also better in children than adults. We conclude that children present earlier with less severe vascular disease and respond better to revascularization, as compared to adult

ISSN:1420-4096    

DOI:10.1159/000174160

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The purpose of this study was to characterize the changes in noradrenergic blood pressure regulation and the causes of this dysregulation in patients with histologically proven primary hyperparathyroidism before and after parathyroidectomy. In untreated hypertensive patients with primary hyperparathyroidism slightly higher plasma levels of norepinephrine, enhanced cardiovascular reactivity to norepinephrine (p < 0.05) and increased cytosolic free calcium concentration in platelets (p < 0.05) were found. Parathyroidectomy resulted in the correction of noradrenergic blood pressure dysregulation and in the reduction of cytosolic free calcium and led to normotension. In vitro incubation of platelets from normal subjects with heterologous plasma ultrafiltrates from either hypertensive patients with primary hyperparathyroidism or normotensive uremic patients with secondary hyperparathyroidism led to raised platelet calcium in primary hyperparathyroidism but not in secondary hyperparathyroidism, although in both conditions intact parathormone levels were elevated equally. Furthermore, when platelets of normotensive subjects were preincubated with commercially available parathormone, no effect on resting platelet cytosolic calcium was observed. Our results suggest that hypertension in primary hyperparathyroidism may be caused in part by noradrenergic blood pressure dysregulation and seems to be causally linked to the secretion of a parathyroid hypertensive factor, which increases cytosolic calcium and alters vascular tone and reactivity.

ISSN:1420-4096    

DOI:10.1159/000174161

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

In anaesthetized dogs fed a diet delivering 3.5 mmol NaCl/kg/day, PD 123319 -an angiotensin (AT) II (Ang II) antagonist preferentially bound to AT-2 receptors -was infused into the renal artery for 20 min at 10 µg/kg/min, the lowest effective dose (group 1 dogs). In group 2 dogs, EXP 3174 (30 µg/kg/min) – an AT-1 blocker – was coinfused while, in group 3, EXP 3174 was infused alone. In all groups, during and immediately after infusion, increased sodium, water, and urea excretions from the infused but not from the contralateral kidney were seen. This increase was the same in all groups throughout the infusion; however, in groups infused with EXP 3174, it persisted even after the infusion had been discontinued. Thus, the total amounts of sodium and water excreted during the whole experiment were higher when EXP 3174 was present in the infusion solution than after PD 123319 alone. Moreover, an increase in glomerular filtration rate (creatinine clearance) and renal blood flow (electromagnetic flowmeter) was seen during the infusion period in groups receiving EXP 3174, but not PD 123319. Although it is possible to assume that blockade of AT-1 receptors only is responsible for the changes in excretion rates as PD 123319 is known to interact with these receptors at high concentrations, it is difficult to explain why it does not react with the same receptors responsible for changes in glomerular filtration rate and renal blood flow. An alternative explanation assumes that the excretory changes are due to blockade of both AT-1 and AT-2 receptors; the identity in effect and the absence of additivity of both antagonists could be explained by the existence of a final common pathway leading to the inhibition of the Ang II effect. This pathway could be reached either from AT-1 or AT-2 rece

ISSN:1420-4096    

DOI:10.1159/000174162

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Several functions of mesangial cells, such as contraction and release of nitric oxide, are dependent on the ambient Cl- concentration. Herein we describe a direct effect of Cl- on mesangial cell membrane conductance. Rat mesangial cells were isolated, cultured, and were patch-clamped in the whole-cell configuration. The external concentration – ([Cl-]o) – of standard Ringer’s solutions was changed isotonically from standard of 160 mM to 35 mM while cell membrane conductance was continuously recorded. Results indicated that control I-V curves of the steady state current had a linear slope conductance of 0.95 nS (n = 10, r = 0.9). In low [Cl-]o, conductance outwardly rectified and increased to 4.1 nS between -120 and 0 mV and to 16.8 nS between 0 and 40 mV (n = 10, r = 0.9;p < 0.01).The increase in conductance occurred within a few seconds and was reversible. Our results show that a large mesangial cell membrane conductance for cations is activated upon exposure to low [Cl-]o<

ISSN:1420-4096    

DOI:10.1159/000174163

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

To evaluate the roles of cAMP degradation on hormonal actions in the kidney, we examined the segmental distribution and activities of cAMP-phosphodiesterase (PDE), a key enzyme for cAMP hydrolysis, in dissected segments of the rat nephron and characterized the isozyme compositions with subtype-specific inhibitors. Summary of the nephron distribution of PDE activities showed that cAMP-PDE activities were detected in all nephron segments and the distal convoluted tubules (DCTs) had the highest activity. Both in proximal convoluted tubules (PCTs) and medullary collecting ducts (MCDs), more than 80% of the total cAMP-PDE activities were inhibited by a nonspecific PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX). In PCTs, rolipram (type-IV PDE inhibitor) was an equally potent inhibitor of IBMX, while 8-methoxymethyl-IBMX (MM-IBMX, type-I PDE inhibitor) and cilostamide (type-III PDE inhibitor) inhibited cAMP-PDE by 35 and 57%, respectively. In MCDs, inhibition by rolipram (40%) was less than that by MM-IBMX (70%) or cilostamide (66%). Rolipram potentiated the parathyroid hormone (PTH)-induced cAMP content in PCTs most effectively. Rolipram and MM-IBMX increased the vasopressin (AVP)-stimulated cAMP content equally in MCDs. Cilostamide had no effect on the cAMP content stimulated by PTH or AVP in PCTs and MCDs. These results indicate that PDE activities were unevenly distributed along the rat nephron and cAMP-PDE was composed of at least three isoforms, namely type I, III and IV in PCTs and MCDs. Among these, type-IV PDE was responsible for hydrolysis of cAMP in PCTs, and type-I and IV PDE were responsible for that in MCDs.

ISSN:1420-4096    

DOI:10.1159/000174164

出版商:S. Karger AG    

年代:1997

数据来源: Karger

ISSN:1420-4096    

DOI:10.1159/000174165

出版商:S. Karger AG    

年代:1997

数据来源: Karger

ISSN:1420-4096    

DOI:10.1159/000313643

出版商:S. Karger AG    

年代:1997

数据来源: Karger

ISSN:1420-4096    

DOI:10.1159/000313644

出版商:S. Karger AG    

年代:1997

数据来源: Karger

ISSN:1420-4096    

DOI:10.1159/000174166

出版商:S. Karger AG    

年代:1997

数据来源: Karger

ISSN:1420-4096    

DOI:10.1159/000174167

出版商:S. Karger AG    

年代:1997

数据来源: Karger