The change in aortic blood density in an in vivo rabbit preparation was measured to assess fluid movement at the pulmonary capillaries caused by infusion of hypertonic solution (NaCl, urea, glucose, sucrose, or raffinose in isotonic saline) into the vena cava over 20 s. The hypertonic disturbance increased the plasma ...

BACKGROUND: Extracorporeal circulation induces increased capillary permeability with fluid leakage into the interstitial space, resulting in positive fluid balance and intravascular hypovolaemia. Hypertonic saline 75 mg.ml-1 in dextran 70, 60 mg.ml-1 (HSD) seems to be of benefit in patients with impaired perfusion. The purpose of the study was to investigate ...

A viscoelastic finite element model of a L2-L3 motion segment was constructed and used to study: (1) the behavior of the intervertebral disc with different amounts of nucleus fluid loss; and (2) the effect of different rates of fluid loss on the viscoelastic behavior of the disc. The results indicate ...

Acute inflammation in skin is accompanied by increased negativity of interstitial fluid pressure (PIF), which will increase capillary fluid filtration and thereby potentiate edema formation. A series of studies indicates that the connective tissue cells in rat dermis are involved in the control of PIF and mediate this response. The ...

BACKGROUND: Hypertonic saline (HS) is increasingly used for fluid resuscitation in hypovolaemic patients. Although the effects of HS have been investigated in animal models, controlled studies in healthy human individuals are few. AIM: The effects of i.v. hypertonic saline 75 mg.ml-1 in dextran 70, 60 mg.ml-1 (HSD) infusion on fluid ...

BACKGROUND: The colloid osmotic pressure (COP) is not routinely assessed during pediatric heart surgery. Two cases of unrecognized hyperoncotic states associated with renal failure have been observed after pediatric heart surgery. We studied the hypothesis that the COP cannot be estimated from the total plasma protein (TPP) or albumin level. ...

Fluctuating high fluid pressures have been reported in pseudojoints after total hip arthroplasty, and may be present throughout the effective joint space. When the pressure extends locally to the bone implant interface, we hypothesized that it might have led to bone resorption. We developed an experimental implant model to study ...

We describe a case where massive air embolism occurred while infusing fluid under pressure with a pressurized infusion system, with fluid bags which contained volumes of air from the manufacturer. We suggest that anesthesiologists be meticulous in de-airing the infusion bag before connecting it to the intravenous infusion system. Also, ...

1. We have investigated the potential contribution of medullary interstitial oncotic pressure to the net balance of forces influencing fluid movement through the walls of the ascending vasa recta (AVR) in the exposed papillae of 2-week-old Sprague-Dawley rats. 2. Using a capillary zone electrophoresis (CZE) assay, hyaluronan (HA) concentrations were ...

Over 170 years after Richard Bright and a century after Ernest H. Starling, the development, location, and severity of edema in patients with renal impairment continue to baffle the predictions of most nephrologists. While much of the phenomenon can be explained by levels of serum proteins, or hydrostatic pressures, there ...

OBJECTIVE: To measure the hydraulic conductivity and reflection coefficient for albumin, as defined by the Starling equation, in rabbit mesentery. METHODS: A section of rabbit mesentery was fixed between two chambers filled with lactated Ringer solution. Flow (Q) of Ringer solution was measured across the mesentery at driving pressures (delta ...

Mechanical compression of cartilage and tendon has been shown to expel fluid both from collagen fibrils and from the extrafibrillar space. As reported previously, albumin (Alb) concentration and colloid osmotic pressure in tendon fluid (TF) expelled by repeated centrifugations fell progressively at increasing centrifugation force (G = 600, 2,400, and ...

We and others have shown that the loss of fluid and macromolecules from the peritoneal cavity is directly dependent on intraperitoneal hydrostatic pressure (Pip). Measurements of the interstitial pressure gradient in the abdominal wall demonstrated minimal change when Pip was increased from 0 to 8 mmHg. Because flow through tissue ...

We introduce a new device and a new technique that facilitate the clearance of postvitrectomy vitreous hemorrhage. We have developed a volume homeostatic fluid-fluid exchanger--Chen's Infusion/Aspiration (Chen's I/A) device. Due to reciprocal synchronized hydraulic action, Chen's I/A provides simultaneous infusion and aspiration of fluid of equal amounts. Therefore, it can ...

The positive xylem pressure (Px) in cucumber hypocotyls is a direct extension of root pressure and therefore depends on the root environment. Solutions of the electrolyte KCl (0-10 osm) reduced the hypocotyl Px transiently (biphasic response), while the Px reduction by mannitol solutions was sustained. The amplitudes of the induced ...

Myocardial edema formation, which has been shown to compromise cardiac function, and increased epicardial transudation (pericardial effusion) have been shown to occur after elevation of myocardial venous and lymphatic outflow pressures. The purposes of this study were to estimate the hydraulic conductance and osmotic reflection coefficient for the epicardium and ...

OBJECTIVE: To investigate the effect of i.v. administration of fluids on the furosemide-induced reduction in right atrial pressure (RAP) and relative change in blood volume (BV) of splenectomized mares. ANIMALS: 5 splenectomized mares. PROCEDURE: RAP was measured by use of a micromanometer placed in the right atrium. Jugular venous blood ...

The relationship between tissue hydrostatic pressure and fluid content is an important determinant of the response of the microvascular exchange system to perturbations. However, only a limited number of studies relating these parameters have been reported. To add to this body of information, fully swollen rat dermis in vitro was ...

Solid tumours have an elevated interstitial fluid pressure (IFP) due to the lack of normal lymphatics, increased permeability of tumour vasculature and an expanding cell population within a potentially limited space. This elevated IFP has been proposed to be an important barrier to the delivery of drugs and marcromolecules. We ...

Sinoaortic baroreceptor denervation (SAD) results in increased osmotically induced secretion of vasopressin (VP) and oxytocin (OT) and increased cardiovascular responses to many centrally acting pressor agents. Studies were conducted to determine whether SAD increases the cardiovascular and endocrine responses to direct and peripheral osmotic stimulation of the supraoptic nucleus (SON). ...

The purpose of this study was to evaluate the effect of applied pressure and measurement time on the in vitro measurement of hydraulic conductance of human dentine. Dentine slices were prepared from 50 third molars. Water was forced through the slices under a constant hydrostatic pressure. Five pressures were tested: ...

A validated mathematical model of microvascular exchange in thermally injured humans has been used to predict the consequences of different forms of resuscitation and potential modes of action of pharmaceuticals on the distribution and transport of fluid and macromolecules in the body. Specially, for 10 and/or 50 per cent burn ...

We have compared 6% hydroxyethyl starch (HES 200/0.5) with 3% modified fluid gelatin (MFG) for volume replacement in major orthopaedic surgery and studied the effects on haemodynamic state, colloid osmotic pressure, blood clotting and plasma homeostasis. Using a controlled, randomized, single-blind clinical design, we studied 46 consecutive patients undergoing major ...

Vasoactive prostanoids may be involved in persistent pulmonary hypertension (PPH) in infants with a congenital diaphragmatic hernia (CDH). We hypothesized that increased levels of prostanoids in bronchoalveolar lavage (BAL) fluid would predict clinical outcome. We measured the concentrations of 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha)), thromboxane B(2) (TxB(2)), protein, albumin, total cell count, ...

Ethanol monitoring is a fairly new method of assessing fluid absorption during transurethral resection of the prostate (TURP). By using an irrigating fluid containing a trace amount of ethanol, the absorption can be measured by expired-breath tests. We describe a TURP in which large-scale absorption of irrigating fluid occurred despite ...

It is suggested that the glomerular capillary membrane constitutes a flexible gel, where negative charges fixed to the matrix of the membrane account for the maintenance of its integrity. In this model, the hydrostatic pressure throughout the membrane is assumed to equal the glomerular capillary pressure. Pglom. of 56.7 mmHg. ...

Recent observations from space missions indicate that weightlessness does not induce an increase in diuresis and natriuresis in astronauts. Rather, both oral fluid and sodium intake as well as renal fluid and sodium output appear reduced compared with the preflight condition. In addition, influences of reduced energy intake may be ...

1. When intra-articular pressure is raised to pathological values (> 9 cmH2O) by saline, the hydraulic conductance of the synovial lining increases manyfold. The increase at 25 cmH2O is only partially accounted for by stretching of the tissue and has been ascribed to washout and/or dilution of interstitial matrix biopolymers. ...

Voluntary hyperventilation (HV) provokes hemoconcentration due to a loss of fluid from the intravascular space. In 10 healthy male volunteers the hypothesis was tested whether HV increases transcapillary fluid shift into the interstitial compartment. For this purpose, fluorescent light intensity (FLI) alterations after intravenous injection of sodium fluorescein (Na fluorescein) ...

It is known that deoxygenated blood is paramagnetic. A ferrofluidic actuator for an implantable artificial heart has been studied. The magnetic fluid consists of ferromagnetic magnetite particles (10 nm). If artificial cells encapsulating ferromagnetic particles are mixed in blood, the circulation is maintained by applying a magnetic field to the ...

Pulse reverse osmosis (1) is a new theory of fluid balance and exchange which suggests that the mean blood pressure and osmotic gradient control fluid balance and that the pulse controls fluid exchange. In vitro testing has confirmed some of the physico chemical principles underlying the theory (2). The hypothesis ...

The progression of animal life from the paleozoic ocean to rivers and diverse econiches on the planet's surface, as well as the subsequent reinvasion of the ocean, involved many different stresses on ionic pattern, osmotic pressure, and volume of the extracellular fluid bathing body cells. The relatively constant ionic pattern ...

OBJECTIVE: Absorption of irrigating fluid may occur through severed blood vessels during endometrial resection. We studied whether irrigating fluid can also be absorbed through the undamaged uterus. PARTICIPANTS: We studied 25 women, aged 28-46 years (mean 38 years), who underwent elective laparoscopic sterilisation under general anaesthesia. INTERVENTIONS: In 15 women ...

In anesthetized adult rabbits, pulmonary perivascular interstitial pressure (P(ip)), measured by micropuncture technique with intact pleural space, averaged -10.5 +/- 1.9 (SD) cmH2O in control conditions, with a wet-to-dry lung weight ratio (W/D) of 4.8 +/- 0.2. Saline infusion (120 ml i.v. over 120 min) induced interstitial edema, increasing P(ip) ...

Earthquake zones in the upper crust are usually more conductive than the surrounding rocks, and electrical geophysical measurements can be used to map these zones. Magnetotelluric (MT) measurements across fault zones that are parallel to the coast and not too far away can also give some important information about the ...

We have previously shown that mucociliary clearance (MCC) decreased during and increased after isocapnic hyperventilation (ISH) with dry air, both in asthmatic and healthy subjects. Inhaled frusemide, an inhibitor of the Na+/K+/2Cl- and NaCl co-transporters on the basolateral membrane of the epithelial cell, prevents the airway narrowing provoked by ISH ...

Although there is much information on the response of spermatozoa from different species to osmotic changes, little has been reported about the mechanism/s by which spermatozoa react to similar changes in the osmotic pressure of the medium. In this study we examine the effect of inhibition of Na (+)K (+), ...

A fluid mechanics study of the Trac catheter was done using a 10 x scaled model. Wall pressure distributions and particle and dye flow visualization studies show that a primary vortex develops due to the spinning tip, and a secondary flow recirculates material along the chamber wall to the base ...

OBJECTIVE: In spite of recent advances in the assessment and treatment of fetofetal transfusion syndrome, its underlying mechanism remains controversial. We aimed to determine whether the clinical features of fetofetal transfusion syndrome could be explained by unidirectional or bidirectional intertwin transfusion along placental vascular anastomoses. STUDY DESIGN: We constructed a ...

Ascites or dialysis fluid in the peritoneal cavity causes fluid loss from the cavity to the body. Experiments in animals and in humans have shown that the fluid loss rate increases with large increments in the intraperitoneal hydrostatic pressure (Pip). We hypothesized that there is a low-threshold Pip above which ...

The mechanically important constituents of swelling tissues are fibers embedded in an osmotically active fluid. The tissues' response to external loading is the sum of contribution of the axial stresses in the fibers and of the fluid pressure. The fluid osmotic properties play a key role in determining its equilibrium ...

We have investigated the spatial variation of local protein concentration and filtration flux by a scintigraphic technique in the ultrafiltration of bovine albumin solutions and blood. The feed was mixed with (99m)Tc albumin macroaggregates and circulated through a polysulfone 30,000 MWCO hollow fiber filter placed in the field of a ...

Postresuscitation organ failure may be associated with detrimental changes in body fluid compartments. We measured how shock and resuscitation acutely alters the interstitial, cellular, and plasma compartments in different organs. Nephrectomized, anesthetized rats were bled to 50 mmHg mean arterial pressure for 1 h, followed by 60 min of resuscitation ...

The liquid content of the hydrocele or watery hernia presses blood vessels of the testis. This pressure occurs in the accordance with hydrostatic and hydraulic laws. However, none of 223. 568 studies on the pressure in mammalian organisms registered worldwide has reported on the pressure values in case of testis ...

The use of multifrequency bioimpedance (MFB) for determination of dry weight (DW) in haemodialysis (HD) patients was evaluated in three studies. In Study 1, the fluid state [total body water (TBW) and extracellular volume (ECV)] was measured by MFB in 82 normotensive patients. 41 hypertensive patients and in 30 healthy ...

A change of interstitial fluid volume (IFV) will normally change the interstitial fluid pressure (Pif) so as to counteract further fluid movement across the capillaries and changes in IFV. Contrary to this, several acute inflammatory reactions in the trachea are associated with increased negativity of Pif, which will 'actively' generate ...

Published experimental results on the activating effect of polyethylene glycol on the interaction of yeast hexokinase with glucose (R.P. Rand, N.L. Fuller, P. Butko, G. Francis and P. Nicholls, Biochemistry, 32 (1993) 5925) are reinterpreted in statistical-mechanical terms of excluded volume. Of particular interest is the ability of this standard ...

In the perioperative period, artificial colloids are most often infused in doses of 500-1000 mL intravenously. This randomized study compared the effects on intravascular volume and coagulation of approximately 2000 mL of two isooncotic artificial colloids: 6% hydroxyethyl starch (HES; MW 200,000; substitution ratio 0.40-0.55) and 3% modified fluid gelatin ...

Hydrops fetalis occurs when the rate of interstitial fluid production by capillary ultrafiltration exceeds the rate of interstitial fluid return to the circulation via lymphatic vessels. Developmental differences in the microcirculation and lymphatic system of the fetus, as compared with mature subjects, renders the fetus susceptible to interstitial fluid accumulation. ...

Elevated interstitial fluid pressure (IFP) may constitute a significant physiological barrier to drug delivery in solid tumors. Strategies for overcoming this barrier have not been developed to date. To identify and characterize various mechanisms regulating IFP and to develop strategies for overcoming the IFP barrier, we modeled the tumor as ...