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Reynolds T - - 2003
The early specification of bioprocesses often has to be achieved with small (tens of millilitres) quantities of process material. If extensive process discovery is to be avoided at pilot or industrial scale, it is necessary that scale-down methods be created that not only examine the conditions of process stages but ...
de Graaff Jurgen C - - 2003
Capillary circulation is delicately regulated by microvascular constriction mechanisms, thereby controlling capillary perfusion and transmural pressure. The influence of posture on capillary flow has been investigated in both diseased and healthy people. However, its influence on capillary pressure has rarely been investigated. We measured capillary pressures in the supine and ...
Ljutić Dragan - - 2003
Arterial hypertension (AH) per se is, together with diabetes mellitus, the most important cause of renal failure and of dialysis in the western world. AH is also a well known consequence of chronic renal disease, and at the same time one of the main factors which causes diabetic and/or non-diabetic ...
Unger Juliane Katharina - - 2003
Capillary membrane filters are devices commonly used for plasmapheresis and recirculating detoxification systems, including plasmaseparation units. Besides clinical trials and case reports, research on plasmafiltration techniques is carried out using in vitro systems. Notably, such hemoperfused in vitro systems require anticoagulation protocols suitable for investigating the clearance performance and hemocompatibility ...
Edgley Amanda J - - 2003
OBJECTIVES: To determine whether 'slow pressor' hypertension from systemic angiotensin (Ang II) infusion was associated with renal vascular structural remodeling of the renal resistance vessels and glomerulus. METHODS: Ang II (4.5-10 ng/kg per min) or vehicle was infused for 10 days. Renal resistance vascular lumen changes were assessed at 10 ...
Kuriki Minoru - - 2003
BACKGROUND: Steroid therapy for IgA nephropathy (IgAN) has been reported to ameliorate the long-term prognosis of IgAN, but its mode of action has not been fully elucidated. In this study, we examined the effect of steroids on glomerular morphological changes in IgAN. METHODS: We examined 16 patients with biopsy-proven IgAN ...
Futrakul Narisa - - 2003
A structural defect of the non-vascular component of a nephron namely vesicoureteric reflex (VUR) can induce injury to the vascular component, which is reflected by the alteration in intrarenal hemodynamics. A mild alteration in intrarenal hemodynamics was observed in grades I-II VUR which revealed (a) mild reductions in renal plasma ...
McDonough Alicia A - - 2003
An acute increase in blood pressure provokes a rapid decrease in proximal tubule salt and water reabsorption that is central to tubuloglomerular feedback regulation of renal blood flow and glomerular filtration rate and contributes to pressure natriuresis. The molecular mechanisms responsible for this critical homeostatic adjustment were studied. When blood ...
Hostetter Thomas H - - 2003
Nearly 70 years ago, the association between reduction in renal mass and subsequent glomerular injury was established. Later the pathologic changes were attributed to adaptive hemodynamic changes in the residual nephrons. This relationship seems to exist in a number of experimental animal species, as well as humans. Among the various ...
Brown Scott A - - 2003
OBJECTIVE: To determine whether the angiotensin converting enzyme inhibitor enalapril would lower systemic arterial and glomerular capillary pressure and reduce the magnitude of renal injury in a canine model of renal insufficiency. ANIMALS: 18 adult dogs that had renal mass reduced by partial nephrectomy. PROCEDURE: After surgical reduction of renal ...
Campbell Ruth - - 2003
BACKGROUND: Proteinuria predicts renal disease progression, and its reduction by angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II receptor antagonists (ARA) is renoprotective. METHODS: In this prospective, randomized, cross-over study of 24 patients with nondiabetic, chronic nephropathies, we compared the effects on proteinuria, renal hemodynamics, and glomerular permselectivity of 8 weeks ...
Sato Y - - 2003
Renal replacement therapy with dialyzers capable of enhanced internal filtration (IF) can be an alternative to standard hemodiafiltration, as it provides convective solute removal comparable to that of hemodiafiltration by a simple procedure. In this study, we clinically evaluated the effect of the hollow fiber length in the dialyzer, a ...
Cullen-McEwen Luise A - - 2003
The loss of one allele for glial cell line-derived neurotrophic factor (GDNF) results in approximately 30% fewer but normal sized glomeruli in young mice. Low nephron number, inherited or acquired, has been linked to increased risk of development of hypertension and renal failure. This study examines whether GDNF heterozygous mice, ...
Martins Alice M C - - 2003
In Brazil, the genus Crotalus is responsible for approximately 1500 cases of snakebite annually. The most common complication in the lethal cases is acute renal failure, although the mechanisms of the damaging effects are not totally understood. In this work, we have examined the renal effects caused by a supernatant ...
LeLorier Jacques - - 2002
BACKGROUND: Selective cyclo-oxygenase (COX)-2 inhibitors (coxibs) produce the beneficial effects of nonsteroidal anti-inflammatory drugs (NSAIDs) while sparing the COX-1-mediated adverse effects on platelets and the gastrointestinal system. However, due to the presence of constitutive COX-2 in the human kidney, coxibs have the same potential for adverse renal effects as traditional ...
Zimanyi Monika A - - 2002
This study investigated the effects of a high-protein diet during pregnancy on nephron endowment and subsequent levels of blood pressure in the offspring. Female WKY rats were fed either a normal (20%, NPD) or a high (54%, HPD) protein diet during pregnancy. Male offspring were paired at birth. At 4 ...
Haltern C - - 2002
Plasmaseparation is a treatment under discussion for critically ill patients, especially in sepsis and multiorgan failure. These patients receive a variety of different fluid substitutes, including hydroxyethylstarch (HES). HES is known to influence rheological properties, but nothing is known about the possible interactions between HES and the plamaseparation procedure. We ...
Wang Angela Yee-Moon - - 2002
BACKGROUND: Left ventricular hypertrophy (LVH) and dialysis adequacy are both important predictors for mortality in dialysis patients. This study evaluated the association between residual renal function (RRF) and the severity of LVH in endstage renal failure (ESRF) patients undergoing long-term continuous ambulatory peritoneal dialysis (CAPD). METHODS: A cross-section study was ...
Krier James D - - 2002
Hypercholesterolemia (HC) is characterized by increased circulating 8-epi-prostaglandin-F(2alpha) (isoprostane), a vasoconstrictor, marker, and mediator of increased oxidative stress, whose vascular effects might be augmented in HC. Anesthetized pigs were studied in vivo with electron beam computed tomography after a 12-wk normal (n = 8) or HC (n = 8) diet. ...
Morikawa Takashi - - 2002
Experimental studies suggest that some long-acting calcium antagonists decrease glomerular hypertension and suppress the progression of nephropathy, but clinical evidence is lacking. To investigate clinically whether a long-acting calcium antagonist, benidipine, lowers glomerular capillary hydraulic pressure via a decrease in efferent arteriolar resistance and decreases proteinuria, we examined hypertensive patients ...
Ataie-Ashtiani Behzad - - 2002
In theories of multiphase flow through porous media, capillary pressure-saturation and relative permeability-saturation curves are assumed to be intrinsic properties of the medium. Moreover, relative permeability is assumed to be a scalar property. However, numerous theoretical and experimental works have shown that these basic assumptions may not be valid. For ...
Ramsey Carla R - - 2002
Renal interstitial hydrostatic pressure (RIHP) is a link between increased arterial BP and natriuresis. The mechanism whereby increases in RIHP inhibits sodium and water transport across the mammalian proximal tubule epithelium may involve changes in flux across the tight junction of the proximal tubule. The purpose of this study was ...
Herrera-Acosta Jaime - - 2002
To study whether prevention of renal injury using the anti-inflammatory drugs pentosan polysulphate (PPS) and mycophenolate mofetil (MMF) is associated with improvement of glomerular haemodynamics, PPS and MMF were compared with losartan. The awake systolic blood pressure (SBP), proteinuria (Uprot) and micropuncture studies were performed 30 days after five-sixths nephrectomy ...
Kiil F - - 2002
To examine whether local myogenic mechanisms account for autoregulation of renal blood flow, a theoretical analysis was undertaken on a model of the pre-glomerular vascular tree consisting of a main and a short, narrow juxtaglomerular segment. At atmospheric extravascular pressure in vitro data are consistent with a relationship r=r0(1 + ...
Kiil F - - 2002
Along the juxtaglomerular segment of the afferent arteriole the luminal pressure p approaches the glomerular capillary pressure of 55-60 mmHg. At such low luminal pressures the myogenic mechanism contracts only if extravascular pressure p(ex) is subatmospheric. According to Poiseuille's formula complete autoregulation requires that blood flow is F=5Kr(0)(4)/Deltax at arterial ...
Gross Volkmar - - 2002
Gene targeting techniques are a revolutionary tool in determining gene function. The mouse is the only mammal in which these methods can be performed. For morphologic and histologic characterization, a broad armamentarium is available for the mouse. However, for functional studies, the 20- to 25-g mouse provides unique challenges. We ...
Toyota Eiji - - 2002
BACKGROUND: The phase difference of coronary arterial and venous flows indicates the importance of intramyocardial capacitance vessels in storing diastolic flow and in discharging volume in systole. However, the anatomic and functional characteristics of the capacitance vessels are unclear. We aimed to clarify those characteristics with their transmural difference by ...
Tanaka Hikaru - - 2002
T-type Ca(2+) channels have properties different from those of the L-type and are involved in cardiac pacemaking and regulation of blood flow, but not in myocardial contraction. Efonidipine is an antihypertensive and antianginal drug with dihydropyridine structure that was recently found to block both L- and T-type Ca(2+) channels. In ...
Brands Michael W - - 2002
1. Hyperglycaemia can lead to hypertension in long- standing diabetes through cumulative effects to cause progressive glomerular injury. However, it is not known how hyperglycaemia directly affects blood pressure control. Moreover, it has been difficult to isolate the actions of hyperglycaemia from other factors that can influence blood pressure. Recent ...
Imig John D - - 2002
Control of glomerular filtration involves sensitive regulation of glomerular filtration pressure over a widely varying range of systemic arterial pressures. This control is exerted through precise adjustments in preglomerular resistance involving numerous activation and feedback mechanisms. Under physiological conditions, these mechanisms succeed in maintaining renal blood flow and glomerular filtration ...
Hansen Henrik P - - 2002
BACKGROUND: The aim of our study was to evaluate the diurnal variation in glomerular filtration rate (GFR), and the potential mechanisms responsible for such variations in GFR and albuminuria in diabetic nephropathy. METHODS: In three 24-hour urine samples, divided into a night- and daytime portion, diurnal variation in albuminuria (ELISA) ...
Bobrova N A - - 2002
A one-dimensional dissipative magnetohydrodynamics code is used to investigate the discharge dynamics of a waveguide for high-intensity laser pulses: the gas-filled capillary discharge waveguide. Simulations are performed for the conditions of a recent experimental measurement of the electron density profile in hydrogen-filled capillaries [D. J. Spence et al., Phys. Rev. ...
Harwood S - - 2001
BACKGROUND: Little is known about the renal handling of endogenous ouabain-like compound (OLC). The aim of this study was to determine the normal renal clearance of OLC and the effect of mild experimental uremia on plasma OLC and its clearance. METHODS: Male Wistar rats were studied 8 weeks after subtotal ...
Suda T - - 2001
BACKGROUND: In glomerular hypertension, mesangial cells (MC) are subjected to at least two physical forces: a high pressure and mechanical stretch. In 5/6 nephrectomized rat, a model of progressive glomerular sclerosis associated with glomerular hypertension, monocyte chemoattractant protein-1 (MCP-1) is expressed in glomeruli, suggesting the possible role of MCP-1 in ...
Bellomo R - - 2001
Septic shock, systemic inflammation and pharmacological vasodilatation are often complicated by systemic hypotension, despite aggressive fluid resuscitation and an increased cardiac output. If the physician wishes to restore arterial pressure (>80-85 mmHg), with the aim of sustaining organ perfusion pressure, the administration of systemic vasopressor agents, such as noradrenaline, becomes ...
Kim S T - - 2001
During hemodiafiltration (HDF) treatment for chronic renal failure patients, replacing large volumes using high-flux membranes with relatively large pores is preferred from the standpoint of enhancing the elimination of large molecules (10 to 50 kd). Aggressive protein-permeable treatment often results in massive leakage of essential albumin, however, which may cause ...
Christensen P K - - 2001
Impaired autoregulation of the glomerular filtration rate (GFR) implies disturbances in the downstream transmission of the systemic blood pressure into the glomerulus, leading to capillary hypertension or hypotension dependent of the level of blood pressure. The impact on renal autoregulation of different antihypertensive drugs in animals has been elucidated, whereas ...
Grimm J B - - 2001
The effects of intramuscularly administered medetomidine and butorphanol (MB), and medetomidine, butorphanol, atropine (MBA) on glomerular filtration rate (GFR) were determined in six dogs as measured by 99m-Tc-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) nuclear scintigraphy. Direct systolic, diastolic, and mean arterial blood pressures and heart rate were measured at regular time intervals ...
Aukland K - - 2001
In the middle of the twentieth century, the suspicion that deep and superficial nephrons might serve different functions created a demand for measurement of single-nephron glomerular filtration rate (SNGFR). Rather unexpectedly, the answer came from Odd E. Hanssen (1917-1964), a Norwegian physician working on his own in the Department of ...
Seghatchian J - - 2001
With the implementation of universal leucodepletion, an in-line, negatively charged LRF6H leucodepleting filter became an essential part of the Haemonetics MCS+ plateletpheresis system. A larger-scale (968) study using the standard protocol revealed a 2.79% leucodepletion failure rate (standard < 5 x 10(6) leucocytes per adult therapeutic dose). Factors influencing the ...
Vallon V - - 2001
For further elucidation of the role of neuronal nitric oxide synthase (nNOS) in macula densa (MD) cells, experiments were performed in anesthetized nNOS knockout mice (nNOS -/-). At comparable levels of arterial BP, renal blood flow was not significantly different between nNOS +/+ and nNOS -/- (1.7 +/- 0.2 versus ...
Ru Q H - - 2001
In capillary electrophoresis and capillary electrochromatography, the driving factor of the separation is electroosmotic flow (EOF). Pressurized capillary electrochromatography, in which the separation is controlled by EOF as well as the pressure, becomes more and more attractive. We studied the influence of various pressures on capillary electrochromatographic separation. The results ...
Ohlson M - - 2001
The effect of shape on the transglomerular passage of solutes has not been hitherto systematically studied. We perfused isolated rat kidneys to determine the fractional clearances (theta) at various filtration rates for four molecules of different shapes but with similar Stokes-Einstein radii (aSE = 34-36 A). The theta for hyaluronan, ...
Gallego B - - 2001
The purpose of this study was to evaluate the functional and structural renal damage observed in aortic-constricted hypertensive rats and to identify their possible relationship with transforming growth factor beta (TGF-beta) expression. Progressive renovascular hypertension was induced by progressive aortic constriction between the two renal arteries. Three months after constriction, ...
Bentzer P - - 2001
The capillary filtration coefficient (CFC) is assumed to reflect both microvascular hydraulic conductivity and the number of perfused capillaries at a given moment (precapillary sphincter activity). Estimation of hydraulic conductivity in vivo with the CFC method has therefore been performed under conditions of unchanged vascular tone and metabolic influence. There ...
Holstein-Rathlou Niels-Henrik - - 2001
Experimental data for tubular pressure oscillations in rat kidneys are analyzed in order to examine the different types of synchronization that can arise between neighboring functional units. For rats with normal blood pressure, the individual unit (the nephron) typically exhibits regular oscillations in its tubular pressure and flow variations. For ...
Guidi E - - 2001
Familial hypertension, glomerular hemodynamic alterations, and dysregulation of tubulo-glomerular feedback (TGFB) have all been associated with the development of chronic renal failure. In the present study we evaluated renal and glomerular hemodynamics and TGFB responses in healthy kidney donors either with or without familial hypertension, before and after nephrectomy. Para-amino-hippurate ...
Denton K M - - 2001
OBJECTIVE: To determine the effects on pre- and post-glomerular vascular resistance of adrenocorticotrophin (ACTH)-induced hypertension in rats, before and after blockade of nitric oxide formation. DESIGN: Four groups of Sprague-Dawley rats were studied. Measurements were made in ACTH- (Synacthen Depot, 0.25 mg/kg twice daily for 8 days) and sham-treated anaesthetized ...
Tiller F M - - 2001
In accord with Darcy's law, the flow rate through a porous bed depends upon the pressure drop deltap(c). In general, increasing deltap(c) leads to increased values of flow rate and average percentage solids in filtration operations. When cakes become super-compactible, their behavior undergoes an unexpected change in which both the ...
Oyanagi-Tanaka Y - - 2001
BACKGROUND: Blood flow in the microvasculature plays a pivotal role in determining the outcome of injury and repair in inflamed tissue. Real-time observation of the kidney microvasculature, including the glomerular capillary tufts, is extremely difficult because of the methodological limitations of currently available microscope optics. In the present study, we ...
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