Intrarenal haemodynamics were investigated in the dog prior to and after relief of 24 hr bilateral ureteral ligation (BUL), by the radioactive microsphere technique. Prior to release of 24 hr BUL there was an about 50% reduction in total blood flow (RBR), with a nearly proprotional decrease in the perfusion ...

The effect of prednisone therapy on renal hemodynamics was studied in normal, autotransplanted as well as homotransplanted dog kidneys. After intravenous administration of prednisone (8 and 16 mg/kg/min) the total blood flow decreased and vascular resistance increased significantly. This effect was more pronounced if the drug was directly injected into ...

This network thermodynamic model of kidney proximal tubule epithelium treats coupled salt and water flow across each component membrane of the epithelium. We investigate the effects of various relative internal parameter values on the concentration of transepithelial flow, the concentrations in the cell and interspace, and the distribution of flows ...

We examined the role of the central nervous system in the activation of the humoral natriuretic mechanism elicited by blood volume expansion. Studies were performed in anesthetized dogs pretreated with deoxycorticosterone acetate (15 mg/day) and sodium chloride for 12 days. An isolated dog kidney perfused with blood from the femoral ...

In normal rats, glomerular plasma flow rates (GPF) were estimated from the uptake of microspheres, and single-nephron filtration rates were estimated by Hanssen's technique in order to calculate single-nephron filtration fractions (SNFF) for outer (C1), middle, (C2), and deep (C3) nephrons. With large microspheres (15 micron), SNFF averaged 0.19, 0.41, ...

1. Radioactively labelled microspheres were used to determine glomerular blood flow in glomerular populations with distinct vascular characteristics. Two batches of microspheres (15 +/- 5.0 micrometer diameter and 7.0--10 micrometer diameter) were utilized. 2. The results show that the larger microspheres overestimate the superficial glomerular blood flow (414 +/- 61 ...

The relationships between immune reactivity after blood transfusions, subsequent kidney allograft survival, and donor selection were studied in dogs. Animals with a high as well as low serological immune reactivity toward antigens contained in blood transfusion were observed. Genetic control of this reactivity or a linkage of this property to ...

1. The effect of infusion of ovine prolactin was studied in anaesthetized dogs pretreated with bromocryptine to reduce the release of endogenous prolactin. 2. Prolactin, injected intravenously and also directly into one kidney, resulted in a 12--18% increase in glomerular filtration rate (GFR) by both kidneys. 3. This increased GFR ...

1. The spectrum of transit times of sodium o-iodohippurate (Hippuran) through the kidney can be derived from an 131I- (or 123I-) labelled Hippuran renogram by deconvolution. In the rabbit and pig, as has previously been shown in man, the frequency distribution curve for the transit times was bimodal. Since the ...

The purpose of the present study was to reexamine the effect of antidiuretic hormone (ADH) and indomethacin (IM) on intrarenal blood flow distribution by applying the microsphere technique to trained consciuous dogs. ADH and IM were given separately and jointly during maximal water diuresis. ADH in itself caused moderate antidiuresis ...

A major factor influencing the movement of plutonium-238 from the lungs to blood after the intubation of oxide suspensions is the presense of 0.001 micrometer diameter particles. In a polydisperse suspension of particles this fraction increases with time, due it is thought, to fragmentation of larger particles induced by alpha ...

Gamma-glutamyl transferase distribution was studied in 10 ewes and 10 lambs; in both groups kidney was the most active organ, followed by pancreas, liver and lungs. In kidney and liver, GGT was bound mainly to cellular structures. Blood GGT activity of 48 lambs was 44 +/- 11 iu/litre and 33 ...

Central nervous system effects have been demonstrated for angiotensin II and suggested for aldosterone. In order to determine whether either of these chemicals naturally crosses the blood-brain barrier, radioactive aldosterone and angiotensin II were introduced via intracardiac injections in rats. Samples of blood, liver, kidney, adrenals, cerebral cortex, and hypothalamus ...

The spontaneous changes in renal plasma flow (RPF) were determined by sodium paraamino hippurate clearance (CPAH) in the individual kidneys of 71 patients with essential and secondary hypertension. These changes were expressed as changes in CPAH and as changes in CPAH per 100 ml Glomerular Filtration Rate (GFR = inulin ...

Non-invasive measurement of organ blood flow can be achieved by tracing the elimination patterns of 133Xe administered by inhalation. An adaption of the method for the estimation of renal blood flow was developed. The 133Xe is accumulated in the tissue by re-breathing for 1 min and the time course of ...

Silicone rubber injections of methyl salicylate-cleared rat kidneys were performed. In 50 of 56 injections of superficial nephrons with their accompanying blood supply, the efferent vessel and early proximal tubule were closely approximated. In 18 of 21 tubular injections filling through the pars recta, the proximal tubule folded upon itself ...

100 ng/kg/min bradykinin was infused into the left renal artery in anaesthetized dogs which were loaded with 10% mannitol in saline to produce a diuresis of approximately 1 ml/min. Bradykinin initially increased renal blood flow (70%), kidney volume (20%). Kidney volume, diuresis and urine osmolarity remained equally changed during continuous ...

Measurement of the spatial distribution of the clearance rate of xenon-133 from the kidney after its injection into the renal artery for estimating intrarenal blood flow can easily be combined with selective X-ray angiography as a routine method. Using a gamma camera as detection equipment anand applying a special computer ...

One hundred machine-preserved cadaver kidneys were transplanted irrespective of their flow rates on the preservation machine. Twenty-five per cent had flows of below 100 ml/min and 11 per cent had flows of below 80 ml/min. There was no correlation between the flow rate and function at 1, 3 or 12 ...

Renal functional parameters were investigated prior to and following release of 24 hr unilateral ureteral ligation (UUL). In the obstructd kidney renal blood flow (RBF) and glomerular filtration rate (GFR) decreased to about 50% and 14%, respectively, as compared to normal controls. Relief of the obstruction did not cause any ...

Sodium arachidonate, 10(-5) g/kg per minute, was infused into the renal artery of a nonfiltering canine kidney in situ in order to determine the effects of enhanced prostaglandin synthesis on renal blood flow and its distribution in circumstances where prostaglandins produced in the medulla could not gain access to the ...

A new method has been developed for the continuous quantification of kidney blood flow, utilizing the unique physical and biological properties of the radioactive tracer couple: rubidium-81/krypton-81m. After intravenous injection, 81Rb concentrates primarily in the kidneys, where it continuously generates the radioactive inert gas 81mKr. This ultrashort-lived isotope is continuously ...

Kidney weight and renal functional parameters were investigated in dogs 7 to 68 days after uninephrectomy. Average enlargement of the remaining kidney amounted to 35.1%. Renal blood flow (RBF) and glomerular filtration rate (GFR) calculated per 100 g actual kidney weight were identical in the non-hypertrophied controls and in the ...

The effect of an artificial O2 carrier (emulsion of the perfluorochemical FC43 with Pluronic-F-108) on the functional capability of the isolated perfused rat kidney was tested. In control series hydroxyethyl starch (HES) instead of fluorocarbon was used. Improving O2 supply in FC 43 experiments raised Na reabsorption to 149 mumol/g ...

In experiments on H mice and Wistar rats it was found that radioactivity was excreted after subcutaneous injection of Damvar-14C preponderantly in urine, and after oral administration, in faeces. After subcutaneous injection the urinary excretion set on very fast. After subcutaneous injection of Damvar-14C to H mice with Crocker's ascitic ...

Collection of urine in rabbits by conventional methods such as catheterization of ureters or bladder with polyethylene tubing or Foley cannulas is hampered by the occurrence of hematuria or obstruction of urine flow, or both. These problems were solved by placing in the bladder a stainless steel device with a ...

The purpose of these experiments was to define changes in glomeruli of rats kidneys which could account for a marked reduction of blood flow immediately following temporary ischemia. After the renal artery had been clamped for 60 minutes, mesangial and endothelial cellular swelling was sufficiently severe to compress and trap ...

Micropuncture studies were done in isolated, blood-perfused dog kidneys to investigate the intrarenal nature of tubuloglomerular feedback regulation of nephron filtration rate. Collections were made at early proximal tubular sites during alterations in flow through the loop of Henle to elicit the feedback response. Renal blood flow in the 10 ...

The present study examined intrarenal blood flow distribution and possible involvement of tubular elements in rats with aminonucleoside (AMN)-induced nephrotic syndrome. Tubular maxima of para-aminohippurate (T M PAH) were determined during mild saline expansion in control rats and in rats on days 4, 5, 6, and 14 following a single ...

A study was made of the metabolism by the rabbit of adenine administered intravenously at a dose of 35 mg/kg with 100 micronCi of 8-14C-adenine. The infused adenine was removed from the blood in two phases, first by diffusion into the tissues and second by metabolic reactions throughout the body. ...

2-Dimethylamino-4-(N-methylanilino)-phenol (MP), an active metabolite of N,N-dimethylaniline-N-oxide in the autocatalytic formation of ferrihemoglobin, reacted quickly in dogs after intravenous injection. A dose of 14C-labeled MP which oxidized 40% of the hemoglobin disappeared from the blood in 20 min. During this period of time MP transferred catalytically electrons from ferrohemoglobin to ...

A noninvasive method for measurement of the individual kidney filtration fraction (FF) is presented, based on an analysis of the early rise of the kidneys' time-activity curves obtained after simultaneous injection of tubular [131I] ortho-iodohippurate and glomerular (Tc-99m DTPA) tracers. The analysis is based on the assumption that an insignificant ...

Microperfusion experiments were performed in rats to assess the effect of luminal application of theophylline and the more lipophilic 3-isobutyl-1-methylxanthine (IBMX) on feedback regulation of glomerular filtration rate. Elevation of loop of Henle flow from 0 to 40 nl/min caused a 20.3 +/- 4.5% reduction of stop flow pressure (SFP) ...

Using direct cannulation of renal lymphatic vessels and simultaneous photography of the exposed dog kidney during urography, the time schedule of variations in lymph flow and kidney size was established. The intravenous contrast injection produced heavy increase of renal lymph flow during the first 8 minutes of urography. Peak values ...

Paired hydronephrotic (HN) and hypertrophic (HT) rat kidneys were studied after 6 days with complete unilateral ureteral obstruction without exposing the kidneys. Total HN renal blood flow (RBF), estimated by total microsphere (MS) uptake and from local 125I-antipyrine (Ap) uptake, averaged about 3/4 of control. HN kidney GFR was reduced ...

Temporal and distributive properties of ureteral peristaltic contractions in the anesthetized pig have been examined. Interperistaltic time intervals have been recorded, and their frequency during different urine flow rates has been compared. The results show that ureteral peristalsis is increased at high urine flow rates to a maximum of approximately ...

1. Intrarenal infusion of frusemide markedly stimulated renin secretion in the isolated perfused kidney of the rat. 2. Renin vales increased from 24+/-6 to 195+/-34 units of secretion rate (renin concentration (nmol angiotensin I/h per litre) X flow rate (ml/min)) following administration of frusemide for 8 min, compared with corresponding ...

1. Selected organ-ablation experiments were performed in dogs in an attempt to identify the source of the natriuretic hormone postulated to participate in the natriuresis of blood volume expansion. 2. An isolated dog kidney perfused with blood from the femoral artery of deoxycorticosterone-loaded dogs subjected to acute volume expansion with ...

Bumetanide (0.25 mg/kg intravenously) increases kidney volume by 20% at maximal diuresis in anaesthetized dogs. The kidney expansion is initially accompanied by a 2-4 fold increase in the subcapsular pressure, which is normalized at a time when kidney volume is still considerably increased. Renal blood flow and urinary kinin excretion ...

Videodensitometry has made it possible to determine not only total but also regional blood flow within the kidney. In animal experiments good agreement was found between the measurements by videodensitometry and isotope technique, taking vein samples, using 125I-labelled Angiografin. The blood flow in 21 human kidney has been determined by ...

Studies were undertaken to determine the biologic distribution of thallium-201 in man. The disappearance from the blood is extremely rapid and intracellular deposition is nearly immediate. The biologic half-time of thallium was measured by both the Brookhaven whole-body counter and the Donner whole-body scanner, with excellent agreement. The effective whole-body ...

The radioactive microsphere method was used to study the distribution of cortical blood flow in anesthetized dogs during water diuresis and during antidiuresis. Infusion of antidiuretic hormone (ADH) at rates ranging from 0.33 to 0.5 mU/kg-min into dogs previously volume expanded with 3% dextrose resulted in an increase in urinary ...

The value of intraoperative blood flow measurement during clinical kidney grafting to predict subsequent function was studied in the course of 19 consecutive transplantations. The results indicate that when blood pressure and heart rate of the recipients are within normal limits there exists a significant relationship between renal blood supply ...

In five female pigs, weighing approximately 100 kg, laparotomy was made under surgical anesthesia. One kidney was removed for immersion fixation and enzyme histochemistry, while the other kidney was fixed by vascular perfusion without prior interruption of the blood flow. A step-by-step description is given of the perfusion procedure, which ...

This report describes the response of the renal circulation to prolonged hemorrhagic hypotension and reinfusion of blood, and to the effect of a variety of drugs (saralasin, indomethacin, and 6-hydroxydopamine, 6-OH-DA). Plastic microspheres were used to measure blood flow perfusing the entire kidney and also the outer cortex, inner cortex, ...

Proximal straight tubules from rabbit kidneys were perfused in vitro in order to study transport of bicarbonate. Total CO2 content was measured in perfused and collected tubule fluid, using microcalorimetry. When the initial perfusate and bath contained 25 mM bicarbonate, the concentration of total CO2 decreased in the collected tubule ...

In 11 mongrel dogs both kidneys have been subjected to a 2 h ischaemic period. One kidney was cooled by perfusing the renal artery at 4 degrees C while the contralateral normothermic kidney was clamped for 2 h. Studying the renal blood flow using the Xenon wash out technique, sequential ...

1. Renal function was measured in seven normo thermic (38 degrees C) and seven hypothermic (27 degrees C) dogs. 2. The glomerular filtration rate was 60 per cent lower in the hypothermic animals, and the renal blood flow as 51 per cent lower. The intrarenal distribution of blood flow was ...

In order to study the effect of anesthesia on the canine response to saline loading, experiments were performed on 10 dogs, first while awake and then during pentobarbital anesthesia. Individual kidney function and intrarenal blood flow response to saline loading (7.5% body weight) were measured in each condition and all ...

The effect on the intracortical distribution of microspheres and radioactivity caused by steric hindrance of the free movement of spheres into afferent arterioles are described by two mathematical models. The results are compared with corresponding experimental data obtained in six kidneys from normotensive dogs. The first model (A) assumes that ...