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Renal Vasculature (renal + vasculature)

Distribution by Scientific Domains

Medical Sciences	85%

Selected Abstracts

Distinguishing Wegener's granulomatosis from necrotizing community acquired pneumonia: A case report and comparison of radiographic findings,

PEDIATRIC PULMONOLOGY, Issue 2 2009
Steven J Spalding MD
Abstract Wegener's granulomatosis (WG) is a necrotizing granulomatous vasculitis, affecting medium to small vessels in the respiratory and renal vasculature. Patients with WG may present with clinical and radiographic features similar to community-acquired pneumonia (CAP), which may delay life-saving immunosuppressive therapy. We report a 14-year-old female originally diagnosed with recalcitrant, necrotizing CAP complicated by massive pulmonary cavitations eventually proven to be WG. We also compare the radiographic features of WG and necrotizing CAP. Pediatr Pulmonol. 2009; 44:195,197. © 2009 Wiley-Liss, Inc. [source]

Anatomy and ultrasonography of the normal kidney in brown lemurs: Eulemur fulvus

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2009
Fidiniaina Raharison
Abstract The purpose of this study is to describe the anatomy and obtain echographic measurements of normal kidneys in brown lemurs (Eulemur fulvus). The anatomical findings show that brown lemur kidneys are comparable to those of rats except for an elongated papilla. The kidneys of 16 (7 females and 9 males) lemurs were examined with two-dimensional and power Doppler ultrasonography under general anesthesia. Morphometrically, the left and right kidney surface areas are comparable (3.29 and 3.51,cm2). Kidney area has a significant linear correlation with body weight. Echo-Doppler findings show that the mean renal arterial blood flow speeds for the left and right kidneys are comparable (0.70 and 0.73,m/s). However, flow speed is higher in the male (0.79,m/s) than in the female (0.60,m/s). The renal arterial diameters are between 1.0 and 1.8,mm. The fact that anesthesia can have hemodynamic effects on renal vasculature should be taken into consideration when assessing these echographic results. Am. J. Primatol. 71:647,653, 2009. © 2009 Wiley-Liss, Inc. [source]

Vascular ,1 -adrenoceptors in isolated perfused rat kidney: influence of ageing

AUTONOMIC & AUTACOID PHARMACOLOGY, Issue 1 2007
S. O. Awe
Summary 1 The present study identifies ,1 -adrenoceptor subtype(s) involved in constrictor responses of the kidney and how ageing influences it. 2 The study was conducted on kidneys from F344BNF1 rats, which unlike F344 or Wistar rats used by many previous investigators do not exhibit glomerulonephritis at advanced age. 3 Noradrenaline (NA) and phenylephrine (PHE) (non-selective ,1) and A61063 (selective ,1A) adrenoceptor agonists elicited constriction of perfused kidneys of young and old rats. The pD2 values (index of renovascular reactivity) were significantly higher for A61603 than for either PHE or NA, and significantly decrease across age groups. 4 BMY 7378 or RS 100329, ,1D - or ,1A -adrenoceptor antagonists, respectively antagonized the constrictor responses and suppressed the maximal responses to all agonists in young adult rat kidneys. However, antagonism of PHE or A61063 by BMY 7378 in old rat kidneys was surmountable. 5 This study suggests that: (i) ,1A and ,1D -adrenoceptor subtypes mediate vasoconstriction of perfused rat kidney; (ii) ,1A -adrenoceptor subtype appears to predominate in renal vasculature based on agonist relative potencies. (iii) Ageing significantly decreases ,1 -adrenoceptor-mediated vasoconstriction of rat kidney. [source]

DIFFERENTIAL NEURAL CONTROL OF GLOMERULAR ULTRAFILTRATION

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2004
Kate M Denton
Summary 1.,The renal nerves constrict the renal vasculature, causing decreases in renal blood flow (RBF) and glomerular filtration rate (GFR). Whether renal haemodynamics are influenced by changes in renal nerve activity within the physiological range is a matter of debate. 2.,We have identified two morphologically distinct populations of nerves within the kidney, which are differentially distributed to the renal afferent and efferent arterioles. Type I nerves almost exclusively innervate the afferent arteriole whereas type II nerves are distributed equally on the afferent and efferent arterioles. We have also demonstrated that type II nerves are immunoreactive for neuropeptide Y, whereas type I nerves are not. 3.,This led us to hypothesize that, in the kidney, distinct populations of nerves innervate specific effector tissues and that these nerves may be selectively activated, setting the basis for the differential neural control of GFR. In physiological studies, we demonstrated that differential changes in glomerular capillary pressure occurred in response to graded reflex activation of the renal nerves, compatible with our hypothesis. 4.,Thus, sympathetic outflow may be capable of selectively increasing or decreasing glomerular capillary pressure and, hence, GFR by differentially activating separate populations of renal nerves. This has important implications for our understanding of the neural control of body fluid balance in health and disease. [source]

Neural control of the renal vasculature in angiotensin II-induced hypertension

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 10 2002
Rohit Ramchandra
Summary 1.,Chronic administration of angiotensin (Ang) II causes an increase in blood pressure via a multitude of actions, including direct vasoconstriction, hypertrophy and increased sympathetic nerve activity. In the present study, we assessed whether the hypertension resulting from chronic AngII alters the ability of the renal vasculature to respond to sympathetic activity. 2.,Angiotensin II was administered for 7 weeks via an osmotic minipump at a dose of 50 ng/kg per min, i.v., to a group of six rabbits. Blood pressure, measured at 0, 1, 2 and 6 weeks after insertion of the pump, increased from 76 ± 2 to 104 ± 6 mmHg at the end of 6 weeks, without any significant change in heart rate. The blood pressure in the control group remained constant at 76 ± 2 mmHg. 3.,After 7 weeks, rabbits were anaesthetized and the renal nerves were stimulated at 0.5, 1, 1.5, 2, 3, 5 or 8 Hz for 3 min at their supramaximal voltage (5.5 ± 1.0 V in the normotensive group and 6.5 ± 1.5 V in the hypertensive group) while the renal blood flow (RBF) response was recorded. Under anaesthesia, there was no difference in mean arterial pressure between the normotensive and hypertensive animals (77 ± 2 and 80 ± 7 mmHg, respectively). The resting RBF under these conditions was not significantly different in the hypertensive group (30 ± 4 vs 26 ± 5 mL/min in the normotensive vs hypertensive group, respectively). 4.,Stimulation at increasing frequencies was associated with increasing reductions in RBF (e.g. 36 ± 8% at 2 Hz in normotensive rabbits and 48 ± 7% at 2 Hz in hypertensive rabbits). However, there were no significant differences between RBF responses in normotensive and hypertensive rabbits. 5.,We conclude that hypertension associated with chronic AngII administration does not alter the response in RBF to electrical stimulation of the nerves. [source]

Neural Regulation Of Renal Blood Flow: A Re-Examination

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2000
Simon C Malpas
SUMMARY 1. The importance of renal sympathetic nerve activity (RSNA) in the regulation of renal function is well established. However, it is less clear how the renal vasculature responds to the different mean levels and patterns of RSNA. While many studies have indicated that small to moderate changes in RSNA preferentially regulate renin secretion or sodium excretion and only large changes in RSNA regulate renal blood flow (RBF), other experimental evidence suggests that small changes in RSNA can influence RBF 2. When RSNA has been directly measured in conjunction with RBF, it appears that a range of afferent stimuli can induce reflex changes in RBF. However, many studies in a variety of species have measured RBF only during stimuli designed to reflexly increase or decrease sympathetic activity, but have not recorded RSNA. While this approach can be informative, it is not definitive because the ability of the vasculature to respond to RSNA may, in part, reflect the resting level of RSNA and, therefore, the vasoconstrictive state of the vasculature under the control conditions. 3. Further understanding of the control of RBF by RSNA has come from studies that have analysed the underlying rhythms in sympathetic nerve activity and their effect on the cardiovascular system. These studies show that the frequency,response characteristic of the renal vasculature is such that higher frequency oscillations in RSNA (above 0.6 Hz) contribute to setting the mean level of RBF. In comparison, lower frequency oscillations in RSNA can induce cyclic vasoconstriction and dilation in the renal vasculature, thus inducing oscillations in RBF. 4. In summary, the present review discusses the neural control of RBF, summarizing evidence in support of the hypothesis that RBF is under the influence of RSNA across the full range of RSNA. [source]