Search Results
Results 251 - 300 of 920
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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 ...
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 ...
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