Pressure‐volume relationships above and below atmospheric pressure in the synovial cavity of the rabbit knee.

Knight, A D; Levick, J. R.

doi:10.1113/jphysiol.1982.sp014273

Cited by 44 publications

(46 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Intra-articular COP was set at zero because intra-articular colloid affects both fluid viscosity and extravascular COP, a complication best avoided in these experiments. Dilution of the endogenous synovial fluid (24 ,u; COP 13 cmH20; Knox et al 1988) by infusate volume (-1-75 x 103 ,ul at 18 cmH20; Knight & Levick, 1982) reduced intra-articular COP to < 02 cmH2O. Studies involving intra-articular fluids of variable colloid content are in progress.…”

Section: Methodsmentioning

confidence: 99%

“…The recorded absorption of fluid from the synovial cavity fell rapidly to zero and intra-articular pressure (Pj) then began to climb, indicating a reversed flow into the synovial cavity. The magnitude of the reversed trans-58 synovial flow was estimated from the rate of pressure rise and the known mean elastance of the system (dPj/dV: Knight & Levick, 1982)…”

Section: Perfusate Transit Timementioning

confidence: 99%

See 1 more Smart Citation

Relation Between Trans‐synovial Flow and Plasma Osmotic Pressure, With an Estimation of the Albumin Reflection Coefficient in the Rabbit Knee

1988

View full text Add to dashboard Cite

SUMMARYThe volume of synovial fluid in a joint correlates inversely with plasma colloid osmotic pressure (COP). The inferred influence of plasma osmotic forces on trans-synovial flow was investigated directly here, in isolated perfused hindquarters of sixteen rabbits. Flow of intra-articularly infused Krebs solution across the synovial lining of the cannulated knee was recorded at controlled intra-articular pressure (18 cmH2O). Colloid osmotic pressure in the synovial microcirculation was varied by perfusion with oxygenated red cells resuspended in albumin solution or plasma from an extra-corporeal system at constant perfusion pressure. Studies in vitro showed that the COP versus concentration curve for commercial bovine albumin samples was variable and not reliably described by a widely used polynomial. The rate of trans-synovial absorption Qs was a positive linear function of intravascular COP T,, (r = 0-936, P < 0 001, n = 83). The average slope dQ,/dl7T was 0-20 ,ul min-' cmH20-' (S.E. + 0-01 lld min-, cmH201), the slope depending on hydraulic conductance and osmotic reflection coefficient. Transsynovial flow was a negative linear function of synovial capillary pressure (Pc). Absolute slope dQ,/d7Tp was on average only 78% of dQ8/dP, in the same joint. The osmotic reflection coefficient of the blood-joint barrier to serum albumin was estimated from these slopes as 0-78-0-81 (S.E.M. + 0 06). Vascular perfusion with a hyperosmolar solution of glucose, sucrose or NaCl generated a transient, rapidly decaying osmotic absorption from the joint cavity, with a half-life of 17-60 s. A reversed osmotic transient occurred on reperfusion with isotonic fluid. It was concluded that the blood-joint barrier, which comprises fenestrated endothelium and synovial intima, approximates to an imperfect semipermeable membrane for albumin solutions, justifying the application of Starling's hypothesis to trans-synovial flow. For small solutes the tissues form a highly permeable but nevertheless slightly osmotically reflective membrane.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Perfusate Transit Timementioning

confidence: 99%

Relation Between Trans‐synovial Flow and Plasma Osmotic Pressure, With an Estimation of the Albumin Reflection Coefficient in the Rabbit Knee

1988

View full text Add to dashboard Cite

show abstract

“…where d V/dPj is the mean compliance of the rabbit synovial cavity at that pressure (Knight & Levick, 1982 Knight, Levick & McDonald, 1988). Five concentrations were investigated (10, 22-5, 55, 110, 150 g l-) and five to six animals were studied at each concentration.…”

Section: Methods In Vitromentioning

confidence: 99%

Effect of extravascular plasma protein on pressure‐flow relations across synovium in anaesthetized rabbits.

McDonald

Levick

1993

The Journal of Physiology

Self Cite

View full text Add to dashboard Cite

SUMMARY1. The effect of extravascular plasma protein on fluid flux through interstitial matrix was investigated in vivo by studying the pressure-flow relation across synovium during intra-articular infusions of protein solutions (usually bovine serum albumin). Synovium is a sheet of non-epithelial cells separated by interstitium-filled gaps, beneath which are fenestrated capillaries: synovium regulates synovial fluid volume and composition.2. Albumin solutions (10-150 g l-) of measured oncotic pressure and viscosity were infused at known pressure into the synovial cavity of knees of anaesthetized rabbits. Flow across the synovial lining in the steady state (absorption rate Q8) was recorded at a series of joint pressures (Ps) to define the pressure-flow relation. Krebs solution was infused into the opposite knee as a control (26 animals).3. Infusion of a low albumin concentration (10 g l-, bovine or rabbit) or diluted rabbit serum revealed no specific effect of plasma protein on interstitial matrix permeability (cf. specific protein effect on capillary glycocalyx permeability). Physiological (22-5 g l-') and higher concentrations reduced trans-synovial absorption rate. The slope of the pressure-flow relation was reduced and the pressure intercept displaced to the right (i.e. P, at zero flow was raised).4. Slope dQo/dP, correlated negatively with intra-articular viscosity (P= 0-001-0-04), in keeping with viscous interstitial flow. The reduction in normalized slope, however, did not equal the reduction in fluidity (1/viscosity) quantitatively. It is proposed that apparent fluidity within the interstitial matrix is higher than in the bulk phase due to steric exclusion of albumin (radius 3-55 nm) by the interstitial glycosaminoglycans. The latter form spaces of estimated mean hydraulic radius 14-18 nm in synovium.5. The joint-pressure intercept at zero net trans-synovial flow was displaced 0.015 cmH20 per cmH20 intra-articular oncotic pressure (nr,; S.E.M. + 0-006). Thus large trans-synovial osmotic gradients were not maintained at physiological flow velocities. The 1-5 % displacement of the P, intercept by nr, was attributed principally to interstitial albumin exerting pericapillary oncotic pressure and enhancing net Starling filtration pressure. Indeed, net trans-synovial flow at low

show abstract

“…The extent to which intra-articular pressure can be expected to mirror changes in periarticular swelling pressure depends on the relative volume and compliance of the synovial cavity and the periarticular tissue. Calculations using estimates of compartment volumes and compliance from Knight and Levick, (1982), Levick and McDonald (1989a, b), Price et al (1996), and Scott et al (2000b) indicate that if the synovium and subsynovium developed an extra Ϫ2.7 cm H 2 O swelling pressure, the intra-articular pressure would change by Ϫ1.6 cm H 2 O, given an injection volume of 10 l at subatmospheric joint pressure (the optimal conditions for detecting the putative effect). Despite its inferred detectability, no such response was seen.…”

Section: Does Cytochalasin Treatment Affect the Synovial Interstitialmentioning

confidence: 99%

“…Compliance values were taken from Knight and Levick (1982). For the control solution the average trans-synovial drainage rate was 3.9 l min Ϫ1 at times corresponding to contralateral t max .…”

Section: Figmentioning

confidence: 99%

Influence of Actin Cytoskeleton on Intra-articular and Interstitial Fluid Pressures in Synovial Joints

Poli

Scott

Bertin

et al. 2001

Microvascular Research

View full text Add to dashboard Cite

Fibroblast microfilamentous actin (F-actin) influences interstitial fluid pressure via linkages to collagen in rat skin (Berg et al., 2001). The present aims were to determine whether the actin cytoskeleton of synovial endothelium, fibroblasts, and synoviocytes influences in vivo (i) fluid exchange between a joint cavity and synovial microcirculation and (ii) extracellular fluid pressures in joints. Rabbit knee joints were treated intra-articularly with the Factin disrupting drugs cytochalasin D and latrunculin B while joint fluid pressure P j was recorded. In joints injected with small volumes of control solution, P j fell with time (؊0.05 ؎ 0.01 cm H 2 O min ؊1 , mean ؎ SEM, n ‫؍‬ 9, equivalent drainage rate 3.9 l min ؊1 ). Cytochalasin or latrunculin reversed this in ϳ4 min in vivo; P j increased with time, e.g., ؉0.12 ؎ 0.04 cm H 2 O min ؊1 at 200 M cytochalasin (equivalent filtration rate into joint 6.6 -12.5 l min ؊1 , n ‫؍‬ 4), with a cytochalasin EC 50 of 45 M. Plasma ␥-globulin clearance into the joint cavity was also increased. Post mortem, cytochalasin did not reverse dP j /dt and had no more effect on P j than did control solution. Also, when synovial interstitial fluid pressures were measured by servonull micropipette post mortem (control ؊0.95 ؎ 0.37 cmH 2 O, n ‫؍‬ 18) cytochalasin had no significant effect on interstitial pressure over 60 min, even at 1 mM. It was concluded that synovial endothelial F-actin has an important role in the normal synovial microvascular resistance to fluid filtration and plasma ␥-globulin permeation and is thus a potential link between pro-in-

show abstract

Pressure‐volume relationships above and below atmospheric pressure in the synovial cavity of the rabbit knee.

Cited by 44 publications

References 20 publications

Relation Between Trans‐synovial Flow and Plasma Osmotic Pressure, With an Estimation of the Albumin Reflection Coefficient in the Rabbit Knee

Relation Between Trans‐synovial Flow and Plasma Osmotic Pressure, With an Estimation of the Albumin Reflection Coefficient in the Rabbit Knee

Effect of extravascular plasma protein on pressure‐flow relations across synovium in anaesthetized rabbits.

Influence of Actin Cytoskeleton on Intra-articular and Interstitial Fluid Pressures in Synovial Joints

Contact Info

Product

Resources

About