Search Results
Results 301 - 350 of 940
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Edwards A - - 1997
The filtration rates for water and a polydisperse mixture of Ficoll across films of isolated glomerular basement membrane (GBM) were measured to characterize convective transport across this part of the glomerular capillary wall. Glomeruli were isolated from rat kidneys and the cells were removed by detergent lysis, leaving a preparation ...
Osgood R - - 1996
The present study describes an experimental model for measurement of glomerular filtration during hypothermic perfusion preservation (HPP). To facilitate glomerular filtration during HPP, perfusate oncotic pressure was reduced by lowering the concentration of hydroxyethyl starch. Lewis rats underwent HPP at a mean perfusion pressure of 40-46 mmHg. An isograft model ...
Jahr J - - 1996
OBJECTIVE: To analyse how prostacyclin interferes with the short-term local circulatory effects of tumour necrosis factor-alpha (TNF alpha) in a skeletal muscle. DESIGN: An autoperfused sympathectomised cat gastrocnemius muscle enclosed in a plethysmograph. INTERVENTIONS: Arterial blood flow, total and segmental vascular resistances (large-bore arterial vessels, arterioles and veins), hydrostatic capillary ...
Gabbai F B - - 1996
Concurrent renal disease appears to augment greatly the adverse effects of systemic hypertension on renal function and the development of glomerulosclerosis. This study examined the effects of systemic hypertension and treatment of hypertension in groups of normal non-nephritic rats and rats submitted to 16 wk of glomerulonephritis induced by the ...
Ziai F - - 1996
The effects of chronic treatment with the specific AT1 angiotensin receptor antagonist, irbesartan, or the angiotensin converting enzyme inhibitor, enalapril, were assessed in uninephrectomized fawn-hooded hypertensive rats (FHH) and compared with vehicle treatment. Three days after uninephrectomy, irbesartan (240 mg/liter), enalapril (80 mg/liter) or vehicle were administered via the drinking ...
Yip J W - - 1996
Glomerular hyperfiltration has been proposed as an independent risk factor for the development of diabetic nephropathy in patients with IDDM. In a case-controlled prospective study of IDDM patients without albuminuria, serial glomerular filtration rate (GFR) measurements were performed over an observation period of 10 years. A group of 25 IDDM ...
Schnabel U - - 1996
Capillary isoelectric focusing was applied to determine the pI value of human rhinovirus serotype 2 (HRV 2), a picornavirus of about 8,500,000 Da in size. Using fused silica capillaries dynamically coated with hydroxypropylmethyl cellulose (added at 0.08% to the catholyte), the virus zone failed to reach the steady state position ...
Kimura G - - 1996
OBJECTIVE: To assess sodium sensitivity and glomerular haemodynamics in patients with primary aldosteronism. DESIGN AND METHODS: Two-week studies were performed in six patients with primary aldosteronism whose diagnosis had been confirmed by histology of the removed adrenal adenoma. Patients were fed normal or sodium-restricted diets for 1 week each and ...
Rázga Z - - 1996
Arteriolosclerosis frequently occurs in IgA nephritis (IgAN), and it is the hallmark of benign nephrosclerosis (BNS). The quantitative ultrastructure of juxtaglomerular arterioles is not known in these disorders. We examined afferent and efferent arterioles in renal biopsies from 25 adult patients with IgAN (hypertension at biopsy: 14 patients) and 9 ...
Kurashina T - - 1996
1. Chronic Na+, K(+)-ATPase inhibition with ouabain induces hypertension in the rat. To examine the role of the kidney in this process, the effect of changes in renal perfusion pressure on glomerular filtration rate, renal blood flow and urinary sodium excretion were determined in rats treated intraperitoneally with ouabain (27.8 ...
Tanner G A - - 1996
Kidney micropuncture and microdissection studies were carried out on heterozygous 2- to 4-month-old female and male Han:SPRD rats with autosomal dominant polycystic kidney disease (ADPKD) and on normal controls, to determine whether cysts are obstructed. Pressures in proximal tubules and cysts were determined using a servo null device and were ...
Silverman D A - - 1996
Theoretical studies have demonstrated a pronounced effect of red blood cell (RBC) spacing on tissue oxygen supply. Our objective was to collect data regarding RBC spacing and related linear capillary hematocrit (Hct) in rat coronary capillaries, from two distinct locations within the capillary bed (proximal and distal portions), in the ...
Barfred Mikael - - 1996
One- and two-dimensional continuation techniques are applied to study the bifurcation structure of a model of renal flow and pressure control. Integrating the main physiological mechanisms by which the individual nephron regulates the incoming blood flow, the model describes the interaction between the tubuloglomerular feedback and the response of the ...
Hansen H P - - 1996
The acute effect of smoking upon arterial blood pressure, urinary albumin excretion rate, glomerular filtration rate and transcapillary escape rate of albumin were investigated in nine normotensive insulin-dependent diabetic patients with microalbuminuria, who had been smoking for 19 (range 4-30) years. In a prospective, open randomized cross-over design, patients were ...
Tanita T - - 1996
Estimation of filtration variables (filtration coefficient, perimicrovascular pressure, and reflection coefficient) is important for evaluating pulmonary microvascular permeability to fluids, especially when the lungs are inflamed, injured, or being preserved for transplantation. Here we report a new method for estimating filtration variables simultaneously in isolated rat lung lobes in zone ...
Morris S J - - 1996
1. Constitutive nitric oxide (NO) synthase has been demonstrated in human skin microvascular endothelial cells; however, the physiological significance of this finding is not known. The aim of this study was to investigate the effects of acetylcholine (ACh), which stimulates the release of NO from endothelial cells, on skin capillary ...
Mackenzie H S - - 1996
In 1988, Brenner, Garcia and Anderson advanced the hypothesis that the nephron endowment at birth is inversely related to the risk of developing essential hypertension in later life. This novel perspective on the origins of essential hypertension was taken from the viewpoint that the development and maintenance of hypertension must ...
Hahn M - - 1996
We have devised a system for analyzing the temporal coherence of capillary pressure (CP) and capillary red blood cell velocity (CBV) variations in humans. The system is designed to measure human blood pressure in skin capillaries by direct cannulation while simultaneously measuring red blood cell velocity in the same capillary ...
Short A C - - 1996
In vivo microscopic observations of pulmonary capillaries are limited to subpleural networks that are less dense than interior networks. In addition to the density difference, subpleural and interior capillary diameters may differ, although there are conflicting data on this point. We measured the diameters of subpleural and interior capillaries in ...
Ito S - - 1996
Alterations in glomerular hemodynamics may play an important role in the progression of renal dysfunction. Accordingly, treating not only systemic hypertension, but also glomerular hypertension is important for conservation of renal function in patients with renal disease. However, glomerular capillary pressure does not necessarily change in parallel with systemic blood ...
Cortes P - - 1996
Glomerular extracellular matrix accumulation may derive from the stretching of mesangial cells caused by excessive glomerular dilatation. The relationship of glomerular volume (VG) to intraglomerular pressure, expressed as compliance or as mean VG in the isolated, perfused rat glomerulus, was used to analyze factors that regulate VG. Glomeruli were highly ...
Leyssac P P - - 1996
Previous studies have given slightly different values of proximal tubular fluid/plasma lithium concentration ratios (TF/P)Li. The aim of the present study was to investigate whether the technique of tubular fluid collection by micropuncture might contribute to this difference. Early distal and late proximal tubular fluid was collected by micropuncture during ...
Jahr J - - 1996
BACKGROUND: The present study aims at analysing short-term effects of TNF alpha on capillary permeability, on transcapillary fluid fluxes, and on vascular tone in a whole organ cat skeletal muscle in vivo preparation. METHODS: The denervated muscle was isolated from the body but with intact vascular supply. The experimental setup ...
Dworkin L D - - 1996
The objective of this study was to determine whether the calcium antagonist amlodipine could slow the progression of chronic renal disease. We examined the effects of amlodipine on kidney structure and function in two experimental models of hypertension. In the first study, adult, male Munich Wistar rats underwent uninephrectomy and ...
Dellanna F - - 1996
Internal filtration is defined as the total water flux across the membrane within the closed blood and dialysate compartment of a dialyser. The aim of our study was to increase convection by increasing the amount of internal filtration and to study the effect on elimination of high and low molecular ...
Scheja A - - 1996
OBJECTIVES: To evaluate an objective and quantitative method for assessment of capillary abnormalities in systemic sclerosis (SSc). METHODS: Nailfold capillaries were investigated by capillary microscopy and photographed in 17 consecutive SSc patients (five with diffuse cutaneous systemic sclerosis (dSSc) and 12 with limited cutaneous systemic sclerosis (lSSc)) and in 17 ...
Mattana J - - 1996
Increased pressure, as may occur with hypertension, may alter cellular function by inducing repetitive mechanical strain. However, increased pressure itself may directly alter cellular function independent of stretching of cells. We undertook the present study to determine whether increased applied pressure could alter uptake of IgG complexes by macrophages. Increased ...
Singhal P C - - 1996
Glomerular hypertension has been considered to play an important role in the development of glomerulosclerosis. Mesangial expansion, a precursor of glomerulosclerosis, may be dependent not only on synthesis of matrix but also on degradation of the deposited matrix. In the present study we investigated the effect of simulated glomerular pressure ...
Mahy I R - - 1995
OBJECTIVES: Previous studies of peripheral microvascular function in human heart failure have concentrated on changes in flow, and there is little information concerning the impact of heart failure on the principal determinants of transcapillary fluid exchange. This study investigated whether alterations in capillary pressure and microvascular fluid permeability can be ...
Karlsen F M - - 1995
Several factors are potentially able to change the glomerular filtration rate (GFR) and thereby participate in its regulation, but only a few factors seem to be physiologically important. The variable nature of proximal tubular pressure should be recognized as important in the regulation of GFR. It is argued that a ...
Peterson J C - - 1995
OBJECTIVE: To examine the relations among proteinuria, prescribed and achieved blood pressure, and decline in glomerular filtration rate in the Modification of Diet in Renal Disease Study. DESIGN: 2 randomized trials in patients with chronic renal diseases of diverse cause. SETTING: 15 outpatient nephrology practices at university hospitals. PATIENTS: 840 ...
Mattana J - - 1995
Substantial in vivo evidence suggests a significant role for glomerular capillary pressure in the pathogenesis of progressive glomerulosclerosis. One presently available in vitro system allows one to study cells while undergoing stretch. However, no comparable system is available to allow one to study in an in vitro system how direct ...
Brown S A - - 1995
To evaluate remnant nephron hyperfiltration, cats underwent sham surgery (group 1, n = 6) or three-fourths nephrectomy (group 2, n = 6). Four to six weeks later, micropuncture studies demonstrated increases (P < 0.01) of single-nephron glomerular filtration rate (SNGFR) in group 2 (28.1 +/- 2.8 vs. 56.0 +/- 5.9 ...
Eaton S A - - 1995
Starling forces and hemodynamics in the digits of 5 horses were studied during early laminitis induced by oral administration of an aqueous extract of black walnut (Juglans nigra). The black walnut extract was prepared from heartwood shavings and was administered by nasogastric tube. Heart and respiratory rates, rectal temperature, central ...
Weindorf N G - - 1995
Capillary microscopy in patients with CVI can show many morphological abnormalities like tortuous and elongated capillaries, heterogenous distribution of capillary tufts or microvascular thrombosis. Microcirculatory changes also become evident when examination is done under different hydrostatic conditions. For this purpose a new fiberoptic microscope was used, with an optical surface ...
Belcaro G - - 1995
Using laser-Doppler flowmetry in association with other noninvasive microcirculatory techniques such as transcutaneous PO2 and PCO2 and capillary filtration measurements it is possible to define two major types of microangiopathy. Low perfusion microangiopathy (LPM) is observed in peripheral vascular disease, essential hypertension, Raynaud's disease etc. High perfusion microangiopathy (HPM) is ...
Kojima S - - 1995
Supraventricular tachycardia (SVT) was induced in 7 patients by programmed cardiac stimulation via an esophageal lead. Blood pressure, renal function, and hormonal factors were measured before, during, and after SVT. The glomerular filtration rate increased during SVT, while renal blood flow did not change. The parameters of glomerular hemodynamics were ...
Mackenzie H S - - 1995
In 1988, Brenner et al advanced the hypothesis that the nephron endowment at birth is inversely related to the risk of developing essential hypertension in later life (Am J Hypertens 1:335-347, 1988). This novel perspective on the origins of essential hypertension was taken from the viewpoint that the development and ...
Hedderwick S A - - 1995
We describe a 29-year-old woman with persistent arterial hypertension which resolved following complete excision of a capillary haemangioblastoma from within the spinal cord at the cervico-medullary junction. Immunohistochemical staining was positive for neuropeptide Y in capillary walls and nerves in the tumour. This raises the possibility of an association between ...
Hansen H P - - 1995
Initiation of antihypertensive treatment (AHT) in hypertensive insulin-dependent diabetic (IDDM) patients with diabetic nephropathy (DN) induces a faster initial (0 to 6 months) and a slower subsequent (6 months to end of observation) decline in GFR [delta GFR (ml/min/month) approximately 1.5 vs. 0.35]. Whether this initial phenomenon is reversible (hemodynamic) ...
Klahr S - - 1995
In the Modification of Diet in Renal Disease Study, a follow-up (mean, 2.2 yr) of 200 study participants with autosomal dominant polycystic kidney disease (ADPKD) was conducted to determine the effect of lowering protein intake and blood pressure on the rate of decline in GFR. The rate of decline was ...
Maki D D - - 1995
BACKGROUND: Although many studies have examined the effects of antihypertensive agents on proteinuria and glomerular filtration rate in patients with kidney disease, many questions remain unresolved. These questions include whether the effects of agents differ, whether their effects are similar in diabetic and nondiabetic patients with renal disease, and whether ...
Lee J - - 1995
The objective of this study was to investigate the structure of capillaries in rat skeletal muscle and their mechanical properties over a wide range of transmural pressures. Capillaries were fixed at controlled pressures and studied with intravital and electron microscopy. Capillary lumen dimensions depend on the local transmural pressure, with ...
Motwani J G - - 1995
We studied six healthy male subjects in a randomized, placebo-controlled, single-blind fashion to determine the comparative effects on renal hemodynamics and natriuresis of the angiotensin-converting enzyme inhibitor enalapril (5 mg on each of 5 days preceding the study), the neutral endopeptidase inhibitor candoxatrilat (200 mg IV), and the combination of ...
Jahr J - - 1995
OBJECTIVE: To analyze the local circulatory effects of prostacyclin in skeletal muscle. DESIGN: A prospective experimental study. SETTING: A university laboratory. SUBJECTS: Twelve adult cats. INTERVENTIONS: The study was performed on autoperfused, sympathectomized gastrocnemius muscle. MEASUREMENTS AND MAIN RESULTS: Arterial blood flow, total and segmental vascular resistances (arterial vessels of ...
Fransen R - - 1995
1. Little direct information is available on the actions of angiotensin II beyond the proximal tubule. We therefore studied the effect of a mildly vasoconstrictive dose of angiotensin II on tubular handling of water, sodium (Na+) and lithium (Li+) in rats by means of free-flow micropuncture at the late proximal ...
Alejandro V - - 1995
Postischemic filtration failure in experimental animals results primarily from depression of the transcapillary hydraulic pressure difference (delta P), a quantity that cannot be determined in humans. To circumvent this limitation we determined the GFR and each of its remaining determinants in transplanted kidneys. Findings in 12 allografts that exhibited subsequent ...
Thorup C - - 1995
Renal effects of acute renal denervation (DNX) were studied in anaesthetized rats. In a first series, whole kidney clearance measurements were made 120 and 240 min after unilateral DNX. At 240 min, urine production was 3.59 +/- 0.87 microL min-1 in control kidneys and 7.74 +/- 1.97 microL min-1 in ...
Hansson L - - 1995
Antihypertensive treatment has been shown to slow down the decline in glomerular filtration rate (GFR) with time. This has been most extensively studied in patients with diabetic nephropathy and, to some extent, with other forms of renal disease. Angiotensin-converting enzyme (ACE) inhibition has been shown to be more effective in ...
Saad W A - - 1995
We investigated the participation of the beta-adrenoceptors of the septa area (SA) in sodium and potassium excretion and urine flow. The alterations in arterial pressure and some renal functions were also investigated. The injection of 2.10(-9) to 16.10(-9) M of isoproterenol, through a cannula permanently implanted into the SA produced ...
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