Limb tourniquet and intramuscular clostridial toxin effects on renal function

1962 ◽  
Vol 17 (1) ◽  
pp. 83-86 ◽  
Author(s):  
James F. Nickel ◽  
John A. Gagnon ◽  
Leonard Levine
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Sodium Excretion ◽  
Renal Vascular Resistance ◽  
Arterial Blood ◽  
Hind Limbs ◽  
Renal Changes ◽  
Anesthetized Dogs ◽  
Peripheral Trauma ◽  
Renal Vascular

Eight anesthetized dogs, given Clostridium perfringens type A toxic filtrate into the hind-limb muscles, showed severe spreading edema, hemoconcentration, marked reduction in para-aminohippurate (PAH) and creatinine clearances, and a rise in the renal vascular resistance. In the first 4 hr sodium excretion fell sharply, and mean arterial blood pressure, slightly. In eight similar dogs venous-occlusive pneumatic tourniquets were applied high on both hind limbs for 90 min. Edema was localized and minimal. Hematocrit was unchanged. PAH and creatinine clearances were extremely low in the second 30-min period of the occlusion but had risen somewhat in the last 30-min period. Sodium excretion was greatly reduced. Arterial pressure and vascular resistance rose very significantly. Upon removal of the tourniquets, PAH and creatinine clearances, blood pressure, and renal vascular resistance returned toward normal. Sodium excretion continued to fall. In many respects the renal changes resulting from two different forms of peripheral trauma are similar. Submitted on August 14, 1959

Renal vascular effects of epinephrine infusion in the halothane-anesthetized piglet

1994 ◽  
Vol 72 (4) ◽  
pp. 394-396 ◽  
Author(s):  
Keith J. Harrington ◽  
Robert G. Allen ◽  
Jay W. Dewald
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Renal Vascular Resistance ◽  
Epinephrine Infusion ◽  
Arterial Blood ◽  
Renal Vascular

The objective of this study was to determine the dose–response effects of epinephrine, given by systemic intravenous infusion to the halothane-anesthetized newborn piglet, on renal blood flow, mean arterial blood pressure, and renal vascular resistance. Seven newborn piglets were acutely instrumented. A transit-time ultrasound flow probe was placed around the renal artery and a femoral arterial catheter was placed for blood pressure monitoring. Epinephrine was infused in doubling doses from 0.2 to 3.2 μg∙kg−1∙min−1. Mean arterial blood pressure increased from 54 mmHg (1 mmHg = 133.3 Pa) to an average of 96 mmHg at 3.2 μg∙kg−1∙min−1 of epinephrine. Renal blood flow increased from 165 mL∙min−1∙100 g−1 at baseline to 185 mL∙min−1∙100 g−1 at a dose of 0.2 μg∙kg−1∙min−1 and increased further at 0.4 and 0.8 μg∙kg−1∙min−1 to reach 261 mL∙min−1∙100 g−1. Renal blood flow began to fall at a dose of 3.2 μg∙kg−1∙min−1, remaining however, significantly above baseline (211 mL∙min−1∙100 g−1). Consequently, calculated renal vascular resistance fell as the dose was increased from 0.2 to 0.8 μg∙kg−1∙min−1 and then rose again at 1.6 and 3.2 μg∙kg−1∙min−1, being significantly above baseline at 3.2 μg∙kg−1∙min−1. These results demonstrate that epinephrine when given by systemic infusion to the halothane-anesthetized newborn pig is a renal vasodilator at low doses and causes renal vasoconstriction at moderate to high doses. Renal blood flow remained above baseline at all doses tested, and thus, within the dosage range tested, epinephrine infusion should not cause renal ischemia.Key words: epinephrine, kidney blood flow, piglet, renal vascular resistance.

Impaired Autoregulatory Responses in Contralateral Kidneys of Two-Kidney, One-Clip Hypertensive Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 381s-384s ◽  
Author(s):  
D. W. Ploth ◽  
R. N. Roy ◽  
Wann-Chu Huang ◽  
L. G. Navar
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Urine Flow ◽  
Renal Vascular Resistance ◽  
Hypertensive Rats ◽  
Contralateral Kidney ◽  
Arterial Blood ◽  
Renal Vascular

1. Micropuncture and clearance experiments in two-kidney, one-clip renal vascular hypertensive rats examined the ability of the kidney contralateral to renal vascular stenosis to maintain renal function during conditions of reduced renal arterial blood pressure. 2. At their respective spontaneous blood pressures, renal vascular resistance was higher and glomerular filtration rate (GFR) and renal blood flow were not different in the contralateral kidneys of the hypertensive rats (170 ± 5 mmHg) compared with normal animals (129 ± 1 mmHg). Urine flow and absolute and fractional excretion of electrolyte were greater from the kidneys of the hypertensive animals. However, pressures in cortical structures were similar in the two groups. 3. As blood pressure was reduced acutely, the kidney contralateral to the renal artery stenosis achieved only small decreases in renal vascular resistance that failed to allow GFR, renal blood flow or pressures in cortical structures to be maintained. In contrast, normal rats efficiently autoregulated renal vascular resistance to allow GFR, renal blood flow and cortical pressures to be unchanged as blood pressure was altered between 130 and 115 mmHg. Urine flow and electrolyte excretion decreased to a greater extent in the hypertensive kidneys; at comparable blood pressure these indices of excretory function were not different in the two groups. 4. These observations indicate that the contralateral kidney can maintain normal haemodynamic and glomerular function only at elevated blood pressure and suggest the possibility that the impaired capacity to autoregulate renal resistances may contribute to the maintenance of hypertension observed in this model.

Frequency modulation of mesenteric and renal vascular resistance

2002 ◽  
Vol 282 (5) ◽  
pp. R1468-R1476 ◽  
Author(s):  
Olaf Grisk ◽  
Harald M. Stauss
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Frequency Modulation ◽  
Low Frequency ◽  
Renal Vascular Resistance ◽  
Pressure Oscillations ◽  
Arterial Blood ◽  
Sympathetic Modulation ◽  
Vascular Beds ◽  
Renal Vascular

The hypothesis was tested that low-frequency vasomotions in individual vascular beds are integrated by the cardiovascular system, such that new fluctuations at additional frequencies occur in arterial blood pressure. In anesthetized rats ( n = 8), the sympathetic splanchnic and renal nerves were simultaneously stimulated at combinations of frequencies ranging from 0.075 to 0.8 Hz. Blood pressure was recorded together with mesenteric and renal blood flow velocities. Dual nerve stimulation at low frequencies (<0.6 Hz) caused corresponding oscillations in vascular resistance and blood pressure, whereas higher stimulation frequencies increased the mean levels. Blood pressure oscillations were only detected at the individual stimulation frequencies and their harmonics. The strongest periodic responses in vascular resistance were found at 0.40 ± 0.02 Hz in the mesenteric and at 0.32 ± 0.03 Hz ( P < 0.05) in the renal vascular bed. Thus frequency modulation of low-frequency vasomotions in individual vascular beds does not cause significant blood pressure oscillations at additional frequencies. Furthermore, our data suggest that sympathetic modulation of mesenteric vascular resistance can initiate blood pressure oscillations at slightly higher frequencies than sympathetic modulation of renal vascular resistance.

Mechanism of circulatory responses to systemic hypoxia in the anesthetized dog

1965 ◽  
Vol 209 (2) ◽  
pp. 397-403 ◽  
Author(s):  
Hermes A. Kontos ◽  
H. Page Mauck ◽  
David W. Richardson ◽  
John L. Patterson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
The Other ◽  
Arterial Flow ◽  
Arterial Blood ◽  
Systemic Hypoxia ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

The possibility that mechanisms secondary to the increased ventilation may contribute significantly to the circulatory responses to systemic hypoxia was explored in anesthetized dogs. In 14 spontaneously breathing dogs systemic hypoxia induced by breathing 7.5% oxygen in nitrogen increased cardiac output, heart rate, mean arterial blood pressure, and femoral arterial flow, and decreased systemic and hindlimb vascular resistances. In 14 dogs whose ventilation was kept constant by means of a respirator pump and intravenous decamethonium, systemic hypoxia did not change cardiac output, femoral arterial flow, or limb vascular resistance; it significantly decreased heart rate and significantly increased systemic vascular resistance. In seven spontaneously breathing dogs arterial blood pCO2 was maintained at the resting level during systemic hypoxia. The increase in heart rate was significantly less pronounced but the other circulatory findings were not different from those found during hypocapnic hypoxia. Thus, mechanisms secondary to increased ventilation contribute significantly to the circulatory responses to systemic hypoxia. Hypocapnia accounts partly for the increased heart rate, but not for the other circulatory responses.

Renal vasodilatation after inhibition of renin or converting enzyme in marmoset

1986 ◽  
Vol 251 (5) ◽  
pp. H897-H902
Author(s):  
D. Neisius ◽  
J. M. Wood ◽  
K. G. Hofbauer
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Angiotensin Ii ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Enzyme Inhibitor ◽  
Renal Vascular Resistance ◽  
Converting Enzyme ◽  
Renin Inhibition ◽  
Renal Vascular

The relative importance of angiotensin II for the renal vasodilatory response after converting-enzyme inhibition was evaluated by a comparison of the effects of converting-enzyme and renin inhibition on renal vascular resistance. Renal, mesenteric, and hindquarter blood flows were measured with chronically implanted ultrasonic-pulsed Doppler flow probes in conscious, mildly volume-depleted marmosets after administration of a converting-enzyme inhibitor (enalaprilat, 2 mg/kg iv), a synthetic renin inhibitor (CGP 29,287, 1 mg/kg iv), or a renin-inhibitory monoclonal antibody (R-3-36-16, 0.1 mg/kg iv). Enalaprilat reduced blood pressure (-16 +/- 4 mmHg, n = 6) and induced a selective increase in renal blood flow (27 +/- 8%, n = 6). CGP 29,287 and R-3-36-16 induced comparable reductions in blood pressure (-16 +/- 4 mmHg, n = 6 and -20 +/- 4 mmHg, n = 5, respectively) and selective increases in renal blood flow (36 +/- 12%, n = 6 and 34 +/- 16%, n = 4, respectively). The decrease in renal vascular resistance was of similar magnitude for all of the inhibitors (enalaprilat -28 +/- 3%, CGP 29,287 -32 +/- 6%; and R-3-36-16 -33 +/- 7%). These results indicate that the renal vasodilatation induced after converting-enzyme or renin inhibition is mainly due to decreased formation of angiotensin II.

Effects of acute acid-base changes on renal hemodynamics in anesthetized dogs

1965 ◽  
Vol 209 (6) ◽  
pp. 1180-1186 ◽  
Author(s):  
Daniel H. Simmons ◽  
Richard P. Olver
Keyword(s):  
Vascular Resistance ◽  
Electromagnetic Flowmeter ◽  
Respiratory Acidosis ◽  
Renal Hemodynamics ◽  
Renal Vascular Resistance ◽  
Left Renal Artery ◽  
Acid Base ◽  
Arterial Ph ◽  
Anesthetized Dogs ◽  
Renal Vascular

Renal hemodynamics were studied in 58 experiments during acid-base disturbances in anesthetized dogs. Renal blood flow was measured with an electromagnetic flowmeter on the left renal artery. Arterial pressure was also measured and renal vascular resistance calculated. Flow and resistance were measured during respiratory acidosis and alkalosis, metabolic acidosis and alkalosis, and combined respiratory and metabolic acid-base disturbances such that arterial pH was maintained normal while pCO2 changed. pH changes were approximately 0.2 unit above and below normal and pCO2 changed to approximately double or half control. Renal vascular resistance was shown to be pCO2 dependent but not pH dependent. Doubling the control pCO2, whether pH changed or remained constant, resulted in decreased resistance (–16%) while decreasing pCO2 to approximately one-half normal resulted in increased resistance (+17%). Resistance was not influenced by the degree of renal denervation resulting from the use of the flowmeter. Changes in resistance appear likely to be related to local rather than central factors.

Diabetic nephropathy

1997 ◽  
Vol 38 (2) ◽  
pp. 296-302 ◽  
Author(s):  
D. Soldo ◽  
B. Brkljacic ◽  
V. Bozikov ◽  
I. Drinkovic ◽  
M. Hauser
Keyword(s):  
Renal Function ◽  
Diabetic Nephropathy ◽  
Vascular Resistance ◽  
Renal Vascular Resistance ◽  
Diabetic Patients ◽  
Renal Changes ◽  
Duplex Doppler ◽  
Renal Vascular ◽  
Parenchymal Thickness ◽  
Renal Length

Background: the purposes of this study were: to compare conventional and duplex Doppler ultrasonography in the detection of renal changes in diabetes mellitus; to investigate whether a correlation was found with various clinical stages; and to assess whether increased renal vascular resistance in asymptomatic patients correlated with mild renal functional impairment. Material and Methods: in 190 diabetic patients and 85 controls, conventional ultrasonography was used to assess renal length, parenchymal thickness, and cortical echo-genicity. Renal vascular resistance was estimated by duplex Doppler measurements of intrarenal arterial resistive indices. According to clinical stage, the patients were classified into 3 groups. Resistive indices were compared between controls and patient groups and correlated with age and renal function. Results: in asymptomatic diabetic nephropathy, renal length and parenchymal thickness were significantly increased compared to that of controls, reflecting hyperfiltra-tion-induced nephromegaly. Differences between controls and patients with clinically manifest nephropathy were insignificant; only in advanced renal disease were both values significantly decreased. Cortical hyperechogenicity was noted only in very advanced disease. Resistive indices correlated well with renal function, and pathologic values (i. e. ≥ 0.70) were observed in 15% in the asymptomatic group and in 87% in the group with advanced nephropathy. Conclusion: Renal changes in diabetic patients are detectable by conventional ultrasound only in very advanced stages of the disease. Pathologic resistive indices, however, may be detected in the earlier stages. Resistive indices correlate with serum cre-atinine levels and creatinine clearance rates. However, it remains unclear as to whether a diagnostic or prognostic benefit can be expected as compared to standard laboratory examinations.

Abnormal Renal Haemodynamics and Renin Suppression in Hypertensive Patients

1970 ◽  
Vol 38 (1) ◽  
pp. 101-110 ◽  
Author(s):  
M. A. D. H. Schalekamp ◽  
M. P. A. Schalekamp-Kuyken ◽  
W. H. Birkenhäger
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Renal Plasma Flow ◽  
Plasma Renin ◽  
Renal Vascular Resistance ◽  
Hypertensive Disease ◽  
Filtration Fraction ◽  
Plasma Renin Concentration ◽  
Renal Vascular ◽  
Intravascular Pressure

1. Intra-arterial pressure, renal plasma flow and glomerular filtration rate were estimated in thirty-two patients with benign essential hypertension. In twenty cases plasma renin concentrations were also determined. Variability of blood pressure was estimated by automatic indirect pressure recording. 2. There was an even distribution between high and low values of renal vascular resistance and filtration fraction. Variability of blood pressure was inversely related to renal vascular resistance. 3. In five patients plasma renin concentration was found to be abnormally low both in the recumbent and in the 45° tilt position. 4. Plasma renin concentration was related to renal blood flow, renal vascular resistance, filtration fraction and variability of blood pressure. 5. The results suggest that in hypertension renin release is suppressed by an increase in intravascular pressure at the level of the juxtaglomerularcells. The extent of renin suppression seems to be related to the stage of hypertensive disease.

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