Search Results
Results 251 - 300 of 934
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Kongstad L - - 1998
Measuring the capillary filtration coefficient (CFC) from the transvascular fluid filtration following a fixed increase in transcapillary hydrostatic pressure is a common method to estimate capillary hydraulic permeability (conductivity) in an organ. Constant flow pump perfusion with an artificial perfusate and a maximally dilated vascular bed are often used in ...
Ronco C - - 1998
BACKGROUND: Hemodialysis using high flux membranes today is a commonly used therapy. The primary advantage is the larger spectrum of molecules removed with these membranes, and the mechanism of removal is in part due to a phenomenon of filtration and backfiltration along the length of the hollow fibers. We hypothesized ...
Cao P - - 1998
Pressure assisting and pressure programming the inlet of the capillary electrophoresis instrument were used for the analysis of peptide mixtures and protein digests using capillary electrophoresis/electrospray ionization-mass spectrometry (CE/ESI-MS). CE/ESI-MS of peptide mixtures and tryptic digests of proteins was studied using three different types of capillary columns: (i) a freshly ...
Smith A C - - 1998
BACKGROUND: Calcium channel blockers (CCBs) are known to have differential effects on both changes in proteinuria as well as progression of diabetic nephropathy. No clinical study, however, has evaluated whether the differential antiproteinuric effects of CCBs may be explained by their effect on glomerular membrane permeability. We, therefore, tested the ...
Mahy I R - - 1998
Capillary filtration coefficient is a critical determinant of fluid flux across the microvascular wall. Changes in capillary filtration coefficient have been described in a number of disease processes. Measurement is typically made by venous occlusion plethysmography using either the upper or lower limb, but a variety of measurement protocols have ...
Ogborn M R - - 1998
We undertook a case-control study to evaluate the renal health of survivors of hemolytic-uremic syndrome (HUS) from the 1991 Arctic epidemic of Escherichia coli O157:H7 gastroenteritis 4 years after the epidemic. Eighteen children who developed HUS during the 1991 epidemic and 18 age- and sex-matched controls from the same community ...
Jia L - - 1998
The present investigation was performed to evaluate the effects of S-nitrosocaptopril, a novel vasodilator possessing the capacities of both an angiotensin converting enzyme inhibitor and an NO donor, on blood pressure and renal function in rats. S-nitrosocaptopril produced acute reductions in mean arterial pressure after both oral dosing (5, 10, ...
Holdstock N B - - 1998
The aim of this study was to determine glomerular filtration rate (GFR), effective renal plasma flow (RPF) and filtration fraction (FF) values in Pony foals during the first 10 days post partum in order to assess any age-related changes and the reliability of the single injection inulin/p-aminohippurate (PAH) method. Arterial ...
Romano G - - 1998
Nephron filtration rate (SNGFR), measured proximally by micropuncture using the technique of total collection of tubular fluid, may be spuriously high as the fall in intratubular pressure during collection may increase the net filtration pressure. Alternatively, the interrupted distal delivery of tubular fluid during proximal collection may up-regulate SNGFR by ...
Kurikawa Y - - 1998
OBJECTIVE: To study if, as predicted by calculations based on 3 Starling pressures, the fourth one, capillary pressure, may increase enough to contribute to joint swelling. METHODS: At magnifying arthroscopy, red cells mostly flow separated from each other in capillaries and precapillary vessels (arterioles). These are emptied of erythrocytes at ...
Ramsey C R - - 1998
Although studies of volume expansion (VE) in the Necturus suggest a major role for paracellular flux in reabsorption by the proximal tubule, results from morphologic or electrophysiologic studies of the effect of VE on the rat proximal tubule suggest only a minor role for paracellular transport. In the present study, ...
Kawabata M - - 1998
The effects of lemildipine, a new dihydropyridine calcium channel blocker, on renal hemodynamics and the tubuloglomerular feedback (TGF) mechanism were examined in anesthetized 9- to 10-wk-old spontaneously hypertensive rats (SHR). Lemildipine, 3 micrograms.kg-1 i.v., did not reduce mean blood pressure (MBP) but tended to increase GFR and increased urinary excretion ...
Ruggenenti P - - 1998
We investigated the predictors of the rate of glomerular filtration rate decline (delta GFR) and progression to end-stage renal failure (ESRF) in the 352 patients with proteinuric non-diabetic chronic nephropathies [urinary protein excretion rate (UProt) > or = 1 g/24 hr, creatinine clearance 20 to 70 ml/min/1.73 m2] enrolled in ...
Klaentschi K - - 1998
The glomerular basement membrane (GBM) is an important component of the filtration barrier that is the glomerular capillary wall. Previously GBM permeability has been investigated only under static pressures and often within a supraphysiological range. We used Matrigel as a model of GBM and formed membranes at the base of ...
Kai T - - 1998
Tsukuba hypertensive mice (THMs) are transgenic mice carrying human renin and angiotensinogen genes. The aim of this study was to evaluate the role of the renin-angiotensin system (RAS) in cardiac hypertrophy and renal disorders in THMs. After a 2-wk control period, 10-wk-old THMs were treated with lisinopril (ACEI group) or ...
Hoogenberg K - - 1998
OBJECTIVES: To assess the effects of low-dose dopamine on norepinephrine-induced renal and systemic vasoconstriction in normotensive healthy subjects. DESIGN: On separate days, either a low-dose dopamine (4 microg/kg/min) or a placebo (5% glucose) infusion was added in a single, blinded, randomized order to incremental norepinephrine infusions of 40, 80, and ...
Yu Y - - 1998
The ultrastructures of anionic sites in rat glomerular basement membranes (GBM) were studied at different perfusion pressures of 100, 150, 200 or 250 cm H2O by a quick-freezing and deep-etching (QF-DE) method, in addition to conventional fixation methods, using polyethyleneimine (PEI) as a cationic tracer. By the QF-DE method, three-dimensional ...
Brauer L P - - 1998
It was previously postulated on the basis of clinical data that the cardiovascular sequelae of extracorporeal whole-body hyperthermia (e-WBH), i.e., hypotension (which requires catecholamine support) results in unique nephrotoxicity in combination with select chemotherapeutic agents. In an attempt to explain this phenomenon, we mimicked e-WBH physiological conditions in a rat ...
Elger M - - 1998
In the present study we provide a detailed structural analysis of the vascular pole of superficial and midcortical glomeruli of the rat kidney. A description of the juxtaglomerular portions of the afferent and efferent arterioles, the extraglomerular mesangium and the glomerular stalk is included. The specific structural elaboration of the ...
Lin W - - 1998
The stop-flow approach was used to investigate where filtration occurs in the pulmonary vasculature after elevation of left atrial pressure and aspiration of HCl. Rat lungs were perfused for 11 min at zero left atrial pressures, and then flow was stopped for 10 min and left atrial pressures were increased ...
Tarif N - - 1997
The vast majority of animal data derived from models of either remnant kidney or diabetes demonstrate that dihydropyridine (nifedipine-like) calcium-channel blockers (DHPCCBs) effectively reduce arterial pressure but do not significantly affect proteinuria nor prevent development of glomerular scarring. Conversely, the non-DHPCCBs such as diltiazem and verapamil blunt both the rise ...
Christensen P K - - 1997
We investigated the effect of acute lowering of blood pressure (BP) upon glomerular filtration rate (GFR) in hypertensive non-insulin-dependent diabetes mellitus (NIDDM) patients, 14 with diabetic nephropathy and 12 with normoalbuminuria. The study was performed twice with the subjects receiving an intravenous injection of either clonidine (150 to 225 micrograms) ...
Aurell M - - 1997
BACKGROUND: Hypertension is a significant cause of end-stage renal failure and effective treatment of hypertensive will reduce the progression rate of chronic renal failure in various kidney disorders. Different classes of drugs may be more effective than others in this respect. In this study we compared the effects on the ...
Dhadwal A - - 1997
A theoretical model is developed to simulate the flow of blood through the capillary network in a single alveolar septum. The objective is to study the influence of random variability in capillary dimension and compliance on flow patterns and pressures within the network. The capillary bed is represented as an ...
Kawata T - - 1997
Effects of dihydropyridine (DHP) Ca2+ channel blocker (CaB) on glomerular hemodynamics are controversial. We examined the effects of two DHP derivatives, benidipine hydrochloride (BDP) and nifedipine (NDP), on glomerular hemodynamics by an in vivo micropuncture method by using spontaneously hypertensive rats (SHRs). Systemic bolus infusion of BDP (4 microg/kg) or ...
Heller J - - 1997
The influence of gradual decline in renal perfusion pressure (RPP) due either to renal artery clamping (C) or to haemorrhagic hypotension (HH) was studied using micropuncture techniques in anaesthetized dogs. The decrease in renal blood flow (RBF) was more profound and set in earlier during HH than during C, where ...
Villa E - - 1997
Rapid degradation of prostacyclin (PGI2) inherent to its molecular structure has long been a major limitation in assessing the natriuretic effect of this prostaglandin. The recent availability of the stable PGI2 analogue iloprost now allows for a comparative study with prostaglandin E2 (PGE2). In the present study conducted in six ...
Vargas F - - 1997
The renal-excretory responses to changes in renal perfusion pressure (RPP) were studied in anesthetized young (3 mo old), adult (12 mo old), and senescent (24 mo old) rats to evaluate whether the pressure diuresis and natriuresis mechanism is altered as a function of age. Experiments were performed in anesthetized animals ...
Boim M A - - 1997
The role of catecholamines in the distribution of intrarenal blood flow and in single-nephron glomerular filtration rate (SNGFR) was evaluated in anesthetized Wistar rats by the Hanssen technique. Epinephrine (EPI) and norepinephrine (NOR) were infused to produce elevations of 20-30 mmHg in mean arterial pressure. Superficial and juxtamedullary nephron perfusion ...
Berrut G - - 1997
Hypertension and non-insulin-dependent diabetes mellitus (NIDDM) are two major risk factors for end-stage renal failure. The value of microalbuminuria (urinary albumin excretion [UAE]: 30-300 mg/24 h) as an indicator of the glomerular filtration rate (GFR) is not known in these patients. METHODS: The relationships between microalbuminuria and GFR in subjects ...
Pecis M - - 1997
OBJECTIVE: To analyze the blood pressure patterns in normoalbuminuric IDDM patients with glomerular hyperfiltration. RESEARCH DESIGN AND METHODS: A controlled cross-sectional study of 38 normotensive normoalbuminuric (urinary albumin excretion rate < 20 micrograms/min) IDDM patients (18 hyperfiltering [glomerular filtration rate > 134 ml.min-1 1.73 m-2] and 20 normofiltering) and 20 ...
Ito S - - 1997
1. The balance of vascular tone of the afferent and efferent arteriole is a crucial determinant of glomerular haemodynamics. Despite their intimate anatomical relationship in the juxtaglomerular apparatus, the mechanisms that regulate afferent and efferent arteriolar tone are different. 2. In the afferent arteriole, two intrinsic mechanisms, the myogenic response ...
Möller A D - - 1997
The dose-response effects of intravenous infusion of prostacyclin on capillary permeability (the capillary filtration coefficient technique), hydrostatic capillary pressure, transcapillary filtration, and vascular tone were analyzed in vivo on cat skeletal muscle from a normal and an increased permeability level. Increased permeability was accomplished by intra-arterial infusion of tumor necrosis ...
- - 1997
BACKGROUND: In diabetic nephropathy, angiotensin-converting-enzyme (ACE) inhibitors have a greater effect than other antihypertensive drugs on proteinuria and the progressive decline in glomerular filtration rate (GFR). Whether this difference applies to progression of nondiabetic proteinuric nephropathies is not clear. The Ramipril Efficacy in Nephropathy study of chronic nondiabetic nephropathies aimed ...
Kimura G - - 1997
It is examined whether glomerular hemodynamics can be indirectly estimated from the pressure-natriuresis relationship. There are only two animal studies reported, one in normal and the other in 5/6 nephrectomized Munick-Wistar rats, which permits plotting the pressure-natriuresis relationship and comparison of indirect estimations with directly measured glomerular hemodynamic data. Normal ...
Rudberg S - - 1997
BACKGROUND: Overt diabetic nephropathy is accompanied by a progressive decline in glomerular filtration rate (GFR). In this study we have investigated if a reduction of GFR already during the transition from normo- to microalbuminuria is associated with glomerular structural changes. METHODS: Seventeen adolescents (11 girls/6 boys) with 10.5 (3.3) (mean, ...
Hall W D - - 1997
The African-American Study of Kidney Disease and Hypertension pilot study randomized 94 nondiabetic black men and women (mean age, 53 years; 75% male) with presumed hypertensive nephrosclerosis and a baseline glomerular filtration rate (GFR) of 25 to 70 mL/min/1.73 m2 (mean, 52.3 mL/min/1.73 m2) to blood pressure control at either ...
Newell S M - - 1997
OBJECTIVE: To determine the effects of 3 sedative protocols (butorphanol and diazepam [BD] IV; acepromazine and butorphanol [AB] IV; diazepam and ketamine [DK] IV) on glomerular filtration rate (GFR) as measured by 99mTc DTPA nuclear scintigraphy and to compare them with GFR measured without sedation. Cardiovascular, respiratory, and sedative effects ...
Ito S - - 1997
The kidney plays an important role in the pathophysiology of hypertension. Recent studies suggest that glomerular hemodynamics may be critically involved not only in the pathogenesis of hypertension but also in the mode of progression of renal dysfunction. The juxtaglomerular apparatus (JGA), consisting of the glomerular afferent and efferent arterioles ...
Poulsen P L - - 1997
OBJECTIVE: To evaluate the relationship between renal function, ambulatory blood pressure (AMBP), and glycemic control in microalbuminuric IDDM patients compared with normoalbuminuric patients. RESEARCH DESIGN AND METHODS: Nineteen male patients (age 33 +/- 6 years) with slight microalbuminuria (UAE 20-70 micrograms/min) were compared with 19 normoalbuminuric (UAE < 15 micrograms/min) ...
Treeck B - - 1997
The effect of the NO synthase blocker N(G)-nitro-L-arginine methyl ester (L-NAME) on glomerular filtration rate (GFR) in outer (OC), middle (MC), and inner cortex (IC) was studied in anesthetized male Sprague-Dawley rats by the aprotinin method. The filtered amount of 125I- and 131I-labeled aprotinin injected before and after L-NAME injection ...
Rakusan K - - 1997
The geometry of the coronary capillary bed in human hearts was studied using samples obtained during cardiac surgery of children operated for tetralogy of Fallot and samples from fresh normal hearts used for valve harvesting. The results revealed a similar coronary capillary density and heterogeneity of capillary spacing in samples ...
Yu Y - - 1997
Wistar rat kidneys were perfused with some fixatives at different pressures of 100, 150, 200 or 250 cm H2O via the aorta and were studied by the quick-freezing and freeze-substitution (QF-FS) or deep-etching (QF-DE) methods, in addition to the conventional immersion or perfusion fixation method. Different parts of glomerular capillary ...
Michell A R - - 1997
Dogs have provided classic models of induced hypertension. This paper shows that despite being susceptible to hypertension, they are naturally resistant to its development even when renal function is severely compromised. The proportion of hypertensive dogs was almost as low among those with reduced glomerular filtration rate (GFR) (9%) as ...
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 ...
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