Previous studies have shown that interstitial fluid pressurization plays an important role in the load support mechanism of articular cartilage under normal step loading. These studies have demonstrated that interstitial fluid pressurization decreases with time if the applied load is maintained constant. In the present study, a theoretical solution is ...

The present experiments were designed to elucidate 1) the role of the lower extremity capillary bed in decreasing plasma colloid osmotic pressure (COP) during immersion of humans (n = 8) for 6 h, and 2) the extent to which the natriuresis of water immersion is triggered by this decrease in ...

The effects of hypertonic saline solution (HSS) and hyperosmotic dextrose (HD; 2,400 mosm/L, 4 ml/kg of body weight) on left ventricular afterload were determined in normovolumic, chloralose-anesthetized, autonomically blocked dogs (n = 8). Solutions were infused IV over 3 minutes. Left ventricular afterload was assessed by use of a dual-tipped ...

OBJECTIVE: To measure the plasma catecholamine concentrations during an episode of haemorrhagic shock treated by intraosseous infusion of a small volume of hyperosmotic fluid in a standardised porcine model. DESIGN: Randomised open study. SETTING: University hospital, Norway. MATERIAL: 14 piglets. INTERVENTION: Two groups of piglets (n=7 each) were anaesthetised with ...

The osmotic behavior of myosin subfragment 1 was studied at 22 degrees C and pH 7.45 in 0.1 m KCl, 2 mm MgCl2, and 10 mm triethanolamine or in 25 mm phosphate, 2 mm MgCl2, and 2 mm MgADP. It was found that, in 0.1 m KCl, myosin subfragment 1 ...

Experiments were done in anesthetized rats to determine systemic hemodynamic and renal functional effects of isovolemic exchange transfusion with either 5% albumin or hemoglobin cross-linked with bis (3,5-dibromosalicyl) fumarate (XLHb) in volumes ranging from 1 to 6.3 ml.100 gm-1. Hematocrit decreased in proportion to increasing exchange volumes with either fluid. ...

1. We have investigated fluid movements between superficial ascending vasa recta (AVR) and the interstitium of exposed papillae of the renal medullae in 15-day-old Sprague-Dawley rats anaesthetized with Hypnorm and Hypnovel. 2. Using a development of the red cell micro-occlusion technique, fluid filtration and reabsorption rates per unit area of ...

The relationship between lenticular colloid osmotic (oncotic) pressure and intraocular pressure is discussed, with particular reference to a postulated buffering reservoir action of the lens in protecting against acute changes in intraocular pressure. A hypothesis is developed regarding acute lenticular volume changes in those species manifesting change in lens shape ...

The architecture of the renal medullary microcirculation is highly specialized. Consistent with their role in countercurrent exchange, the vessels (the vasa recta and the intervening capillaries) have high permeabilities to fluid and small hydrophilic solutes. The urea permeability of the continuous endothelium of the descending vasa recta (DVR) in the ...

BACKGROUND: Patients' blood or other potentially infectious body fluids frequently pass through surgeons' gowns in the operating room. These fluids are absorbed by the scrub suit and can directly contaminate the surgeons' skin. Protective barriers remain an important method of exposure control for many blood-borne pathogens. The efficacy of surgical ...

Theoretical treatments predict that strong entropic pressures between adjacent bilayer membranes can arise from out of plane motions caused by either thermally induced bending undulations of the entire bilayer [Harbich, W., & Helfrich, W. (1984) Chem. Phys. Lipids 36, 39-63; Evans, E. A., & Parsegian, V. A. (1986) Proc. Natl. ...

The effects on fluid balance, pulmonary functions and economics were evaluated in a randomized comparison of one colloid free and three colloid containing fluid regimens, for 48 hours during and after coronary artery bypass (CAB) surgery. A standard regimen for anaesthesia, extracorporeal circulation and monitoring was used. Only Ringer's acetate ...

The study evaluated the warming ability and flow rates associated with four fluid warming devices during pressure driven infusion and during wide open gravity driven roller clamp infusion. Warmers tested were the Astotherm, Flotem IIe, Level 1 System 250 and a modified cardioplegia heat exchanger. Fluids tested were crystalloid, red ...

Experiments were performed to provide information on the mechanisms of the formation of gingival fluid in rats and on the determinants of its flow and composition. For this purpose we studied the effect of increasing net capillary filtration by venous stasis induced by multiple ligations of the jugular vein or ...

1. Hyaluronan is the major polysaccharide of synovial fluid, responsible for its high viscosity. The effect of hyaluronan on fluid transport across the synovial lining of the joint was investigated. Rate of fluid absorption from the joint cavity (Qs) was measured at intra-articular pressures (Pj) of up to 24 cmH2O ...

Fluid accumulation in the interstitium is frequently found after cardiac surgery. In extreme this can lead to pulmonary and myocardial oedema. The origin of this accumulation is not exactly known and may be twofold. It is probably a combination of the noninfectious whole body inflammatory response and a change in ...

The combined effects of hydrostatic pressure and osmotic pressure, generated by polyols, on the spin equilibrium of fenchone-bound cytochrome P-450cam were investigated. Hydrostatic pressure indices a high spin to low spin transition, whereas polyols induce the reversed reaction. Of the four solutes used, glycerol, glucose, stachyose, and sucrose, only the ...

The cleavage specificity of the Pvu II and BamHI restriction endonucleases is found to be dramatically reduced at elevated osmotic pressure. Relaxation in specificity of these otherwise highly accurate and specific enzymes, previously termed "star activity," is uniquely correlated with osmotic pressure between 0 and 100 atmospheres. No other colligative ...

To study the transmigration of fluid rapidly infused intravenously, lactated-Ringer's solution was infused at the rate of 90 ml/kg/hr for 30 min into generally anesthetized dogs. Four groups were made; group C with no fluid infusion as the control, group F with rapid fluid infusion only, group LF with renal ...

Cavities were prepared in human premolars scheduled for extraction for orthodontic reasons. The smear layer was removed from the dentin surface by acid etching, and the cavity was sealed using a hollow chamber. The chamber was filled with sterile saline solution and connected via tubing to a hydraulic circuit featuring ...

Prostaglandins exhibit a variety of cardiovascular actions that may affect the hemodynamic recovery of the ischemic myocardium after cardiopulmonary bypass. We have observed a decrease in the mean arterial pressure on autotransfusion of the accumulated pleural cavity fluid during operation. One aim of this study was to determine the concentrations ...

OBJECTIVES: To characterize the changes in colloid osmotic pressure during delivery and to determine the relationship between maternal and fetal colloid osmotic pressures. DESIGN: Clinical, prospective study. SETTING: Obstetrical operating theater in a tertiary care university hospital. PATIENTS: Thirty healthy parturient patients, at term gestation receiving spinal anesthesia for elective ...

Open-ended plastic tubes were used as capsules for obtaining interstitial fluid from rabbits. The capsule was a 2.5 cm long plastic tube with an inner diameter of 6 mm. Three small incisions were made in the dorsal mid-line of the anaesthetized rabbit; two capsules were inserted into each incision. A ...

The diameter of the actin filament decreases with an increase of the protein osmotic pressure. This phenomenon is accompanied by a decrease of the angle (alpha) formed between the long axis of the actin monomer and the pointed end of the filament axis. At 1.8 x 10(5) dyn/cm2 (the protein ...

Detrimental changes of blood and erythrocyte rheology, and fluid exchange between the vascular and interstitial spaces, which influence the rate that oxygen is supplied to the patient, occur during cardiac bypass surgery. Venous flow is subject to a pulsatile and uncertain variation, because the vena cava is more than 30 ...

The effects of hydrostatic pressure on the KCl co-transporter of equine erythrocytes were studied to determine factors involved in its regulation. Pressure (0.1-40MPa) increased Cl-dependent K+ transport; in the presence of the putative kinase inhibitor N-ethylmaleimide (NEM) which stimulates the transporter, or the phosphatase inhibitor calyculin A, pressure had no ...

OBJECTIVES: To study the peritoneal fluid loss rate, the clearance (CI) of radioactive tracer albumin (RISA) eliminated from the peritoneal cavity (PC), as well as the peritoneal-to-plasma RISA clearance (CI-->P) during acute peritoneal dialysis (PD) at large elevations in intraperitoneal hydrostatic pressure (IPP). DESIGN: Experimental study in anesthetized Wistar rats. ...

This study examined the relationship between rat (mature Sprague-Dawley males) thoracic aortic wall and intraluminal pressure responses to a dynamic pressure input. High speed video image (Do) of outer wall area and intravascular pressure (Po) responses of the in vitro aorta were digitized and computer recorded during swept frequency pressure ...

The effect of hyperosmolar fluid aspiration (seawater) on lung fluid balance has not been well studied. Therefore, the effect of this clinically relevant form of acute lung injury on the alveolar epithelial and lung endothelial barriers was examined in ventilated, anesthetized rabbits. Seawater (4 ml/kg body weight, 881 +/- 29 ...

Previous studies from the authors' laboratory have shown that controlled limb perfusion after prolonged, acute ischaemia minimizes reperfusion injury. The present study was performed to investigate the role of osmotic and colloid-osmotic pressure in the initial reperfusate in order to reduce postischaemic limb oedema and subsequent reperfusion injury. A total ...

Luminal fluids were collected in vivo by micropuncture and cannulation from the rete testis, efferent ducts and ductus epididymidis of the rat to determine the composition of efferent duct fluids and the rates of reabsorption of water and solutes by the efferent ducts. The concentration of spermatozoa increased by a ...

Three out of the four Starling pressures were determined at arthroscopy of traumatic effusions of the knee. The range of the joint fluid hydrostatic pressure Pjoint was 5-83 cmH2O (0.5-8.1 kPa, 4-61 mmHg), that of the colloid osmotic pressure difference COPplasma-COPjoint 0-21.7 cmH2O. In 11 of 15 cases the sum ...

Fluid movement into the peritoneal cavity results after instillation of a hypertonic solution. Some investigators have assumed that the peritoneum is a significant barrier to small solutes and have predicted that fluid would be drawn by an osmotic gradient into the cavity from the tissue surrounding the peritoneal cavity, resulting ...

Experimental studies have confirmed the clinical impression that large bilateral pleural effusions are able to raise the pressure in an otherwise hemodynamically insignificant pericardial effusion to a level sufficient to produce right ventricular diastolic collapse (RVDC). The hemodynamic consequences of this syndrome are not as severe as when the intrapericardial ...

The structure and interactive properties of liquid-crystalline egg phosphatidylcholine (EPC) bilayers containing the ganglioside GM1 and its uncharged analogue, asialoGM1 (AGM1), have been obtained by X-ray diffraction analysis of osmotically stressed liposomes. Both electron density profiles and reciprocal space modeling indicate that (1) the incorporation of up to 30 mol ...

The pleural cavity is created between the 4th and 7th week of embryologic development and is lined by the splanchnopleurae and somatopleurae. These embryonic components of visceral and parietal pleurae develop different anatomic characteristics with regard to vascular, lymphatic, and nervous supply. Both pleurae have two layers: a superficial mesothelial ...

In order to investigate the different contactile effects between intraluminal and extraluminal vasoactive agents, we studied the contractile responses of rabbit basilar artery to selective intraluminal and extraluminal administration of potassium, serotonin and histamine in vitro. We also studied how the physical pressure gradients, such as hydrostatic or osmotic pressure ...

A revised circuit design for modified ultrafiltration is presented rendering the technique more convenient for use after cardiopulmonary bypass when blood cardioplegia is used. The procedure employs a hollow-fiber ultrafiltration device attached to the cardioplegia circuit. A bubble trap, heat exchanger, and a pressure monitor are incorporated as safety features. ...

OBJECTIVE: Our purpose was to study the effect of operator transducer pressure on amniotic fluid index and single deepest pool measurements and their intraobserver and interobserver variability. STUDY DESIGN: Forty subjects in the third trimester with intact membranes were studied by two observers at three predetermined operator pressures. Pressure was ...

1. Surgery and radiotherapy to axillary lymph nodes during breast cancer treatment is often followed, commonly years later, by chronic postmastectomy oedema (PMO). PMO is considered a 'high protein' oedema due to reduced axillary lymph drainage. Since oedema formation also depends on fluid input (capillary filtration), we studied the Starling ...

The objectives of fluid therapy in the burned child can be simply stated and defined, and they should represent the basis for the resuscitation process. During the first 24 h after the burn, the ultimate goal is restoration of the patient's volume and electrolyte homeostasis. All efforts should be directed ...

This investigation used a previously described bench-top device (Gaver et al., J. Appl. Physiol. 69: 74-85, 1990) to examine the role of nonnewtonian and viscoelastic fluids on events at reopening of a closed flexible tube. Aqueous sodium alginate solutions with and without calcium chloride and sodium dodecyl sulfate in desired ...

PURPOSE: To assess the use and validity of a mean systemic filling pressure analogue (Pmsa) in the closed-loop control of fluid replacement in continuous hemodiafiltration. METHODS: Cardiovascular variables were computer acquired from bedside monitor. Pmsa was calculated and compared with a target value. Gravitational fluid replacement to the extracorporeal hemodiafiltration ...

OBJECTIVE: To evaluate experimentally the conditions necessary for the formation of serous detachments. METHODS: Selective injury to the retinal pigment epithelium (RPE) and choriocapillaris was produced in cats using weak laser burns and intense diffuse light, with or without photosensitization with rose bengal. The fundi were analyzed by observation, fluorescein ...

To characterize the role of water in protein-DNA interactions, we have studied the specificity of the EcoRI restriction endonuclease as a function of osmotic and hydrostatic pressure. The extent of cleavage by the enzyme at noncanonical ("star") sites is shown to depend uniquely upon the osmotic pressure in the reaction ...

Experiments were done to study the effects of porcine relaxin on osmotically evoked changes in intramammary pressure and the release of oxytocin and vasopressin in anaesthetized rats. Injections (1 microliter) of hypertonic (0.75 M) NaCl into the left lateral cerebral ventricle were used to induce consistent rises in intramammary pressure ...

We studied the trans compartmental speed of urea transfer by comparing concentration changes of blood urea nitrogen to mass changes of urea during 80 dialyses in six patients. The speed of urea transfer was studied as a dependent factor of 15 patient characteristics: age; gender; fluid overload; and pre and ...

The hydrodynamic theory of dentin sensitivity holds that pain is evoked by stimuli producing minute shifts in tubule fluid. In human volunteers hydrostatic pressures were applied to prepared dentinal cavities. The subjects reported the magnitude and quality of their sensations of pain by means of an intermodal matching technique in ...

A new experimentally testable hypothesis is advanced for the mechanosensory transduction mechanism by which communicating osteocytes sense the very small in vivo strains in the calcified matrix components of bone. We propose that the osteocytes, although not responsive to substantial fluid pressures, can be stimulated by relatively small fluid shear ...

OBJECTIVE: We compared fluid absorption, blood loss, and immediate postoperative complications in transurethral resection of the prostate (TURP) performed with the continuous flow and the intermittent flow irrigation techniques. We also studied pressure conditions under which fluid absorption occurs when continuous flow irrigation is used. METHODS: One experienced urologic surgeon ...