Interstitial exclusion of macromolecules studied by graded centrifugation of rat tail tendon

1997 ◽  
Vol 273 (6) ◽  
pp. H2794-H2803 ◽  
Author(s):  
Knut Aukland ◽  
Helge Wiig ◽  
Olav Tenstad ◽  
Eugene M. Renkin
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Colloid Osmotic Pressure ◽  
Collagen Fibrils ◽  
Free Fluid ◽  
Mechanical Compression ◽  
The Third ◽  
Tail Tendon ◽  
Molecular Sieving ◽  
Rat Tail

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 13,100), suggesting either molecular sieving in compressed tendon or mobilization of protein-free (excluded) fluid. The present experiments, including analysis of 51Cr-EDTA, aprotinin (Ap), Alb, immunoglobulin G (IgG), and hyaluronan (hyaluronic acid; HA) with molecular weight (MW) ranging from 341 to 5 × 106, strongly favored the exclusion hypothesis; the fraction of Alb, IgG, and HA-free fluid (excluded) was already 0.23–0.36 in the first centrifugate, increasing to 0.73–0.82 in the third. The corresponding numbers were, respectively, 0.11 and 0.43 for Ap (MW 6,500), and 0 and 0.08 for51Cr-EDTA. These data, combined with calculated exclusion by collagen fibrils, proteoglycans, and HA, indicated that the first centrifugate was mainly derived from the extrafibrillar space, with increasing addition of macromolecular free intrafibrillar fluid in the second and third centrifugates, with each space contributing about equally to the total centrifugate volume. The calculations also indicated that Alb-, IgG-, and Ap-free fluid was mobilized from extrafibrillar space by increasing overlap of excluded territories. An excess of HA in tendon compared with that estimated from centrifugate concentrations suggests a large bound or immobilized HA fraction.

An Estimate of the Mean Length of Collagen Fibrils in Rat Tail-Tendon as a Function of age

1989 ◽  
Vol 19 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Alan S. Craig ◽  
Mervyn J. Birtles ◽  
James F. Conway ◽  
David A.D. Parry
Keyword(s):  
Collagen Fibrils ◽  
The Mean ◽  
Tail Tendon ◽  
Rat Tail

Distribution volumes and macromolecular mobility in rat tail tendon interstitium

1991 ◽  
Vol 260 (2) ◽  
pp. H409-H419 ◽  
Author(s):  
K. Aukland
Keyword(s):  
Total Protein ◽  
Interstitial Fluid ◽  
Colloid Osmotic Pressure ◽  
Fluid Composition ◽  
Macromolecular Transport ◽  
Interstitial Volume ◽  
Centrifugation Technique ◽  
Tail Tendon ◽  
Distribution Spaces ◽  
Rat Tail

This study explores a centrifugation technique for estimating interstitial fluid composition and macromolecular transport. Rat tail tendon supported by a nylon net was subjected to three consecutive 15-min centrifugations at 3,000, 6,000, and 14,000 revolutions per minute (rpm) or 3, 10, and 20 min at 6,000 rpm. Colloid osmotic pressure (COP) and concentrations of albumin, total protein, and hyaluronan in subsequent centrifugate fell as exponential functions of accumulated centrifuged volume, reaching 10-30% of initial level at an accumulated volume corresponding to 8% of tendon volume. Intercepts for zero centrifugation were 11 mmHg (COP), 22 mg/ml (albumin), and 39 mg/ml (total protein), probably reflecting concentrations in protein-accessible interstitial volume. Corresponding serum values were 19 mmHg, 34 mg/ml, and 63 mg/ml. Tendon distribution spaces were 0.62 (H2O), 0.57 (51Cr-labeled-EDTA), and 0.22 ml/g wet wt (albumin). The progressive fall in centrifugate concentrations probably reflects increasing resistance to macromolecular transport, with a sieving coefficient for albumin falling from 1 to 0.35, or increasing contribution of fluid from protein-excluded space. The effect was reversed by rehydration, which caused increased concentrations in centrifugate. Low hyaluronan concentrations in centrifugate (0.25 mg/ml) compared with that of whole tendon (0.4 mg/g wet wt) reflect either a large "bound" fraction in tissue or marked sieving of hyaluronan in normohydration.

Tendon and ligament from the horse: an ultrastructural study of collagen fibrils and elastic fibres as a function of age

1978 ◽  
Vol 203 (1152) ◽  
pp. 293-303 ◽  
Keyword(s):  
Flexor Tendon ◽  
Extensor Tendon ◽  
Collagen Fibrils ◽  
Collagen Content ◽  
Elastic Fibres ◽  
Suspensory Ligament ◽  
Tail Tendon ◽  
Fibril Diameter ◽  
Rat Tail ◽  
Diameter Distributions

A study has been made of the ultrastructural organization of the collagen fibrils and elastic fibres in tendons and ligaments from horses of ages ranging from 2 months premature to 19 years. Diameter distributions of the collagen fibrils in the common digital extensor tendon, the superficial flexor tendon and the suspensory ligament are unimodal in the foetal tissue and at birth, and at these stages of development the three collagenous tissues are virtually indistinguishable. However, at maturity, the ligament and flexor tendon have bimodal distributions similar to that found for rat-tail tendon. The fibril distribution for extensor tendon remains unimodal until the onset of maturity, beyond which the distribution becomes bimodal. Fibril diameter distributions for ligament, extensor and flexor tendon at old age are, as at birth, virtually identical. An estimate has been made of fibrillar collagen content in the three tissues as a function of age. As with rat-tail tendon, the collagen content increases steadily from birth to maturity, at which stage the content remains fairly constant though it does drop slowly with increasing age. The presence of well developed elastic tissue in foetal and immature tendon and ligament shows that the development of the elastic fibres does not parallel the development of the collagen fibrils. In diseased tissues from a 3 year suspensory ligament and an 8.5 year superficial flexor tendon only immature elastic fibres have been observed. Furthermore, since the collagen fibril diameter distributions in these specimens show a marked change from the norm, it would be expected that the mechanical properties of these tissues would be altered significantly.

scholarly journals The supramolecular structure of bone: X-ray scattering analysis and lateral structure modeling

2016 ◽  
Vol 72 (9) ◽  
pp. 986-996 ◽  
Author(s):  
Hong-Wen Zhou ◽  
Christian Burger ◽  
Hao Wang ◽  
Benjamin S. Hsiao ◽  
Benjamin Chu ◽  
...  
Keyword(s):  
Collagen Fibrils ◽  
Bone Collagen ◽  
X Ray ◽  
X Ray Scattering ◽  
Mineralized Tissues ◽  
Collagen Molecules ◽  
Tail Tendon ◽  
Lateral Structure ◽  
Rat Tail ◽  
Ray Scattering

The evolution of vertebrates required a key development in supramolecular evolution: internally mineralized collagen fibrils. In bone, collagen molecules and mineral crystals form a nanocomposite material comparable to cast iron in tensile strength, but several times lighter and more flexible. Current understanding of the internal nanoscale structure of collagen fibrils, derived from studies of rat tail tendon (RTT), does not explain how nucleation and growth of mineral crystals can occur inside a collagen fibril. Experimental obstacles encountered in studying bone have prevented a solution to this problem for several decades. This report presents a lateral packing model for collagen molecules in bone fibrils, based on the unprecedented observation of multiple resolved equatorial reflections for bone tissue using synchrotron small-angle X-ray scattering (SAXS; ∼1 nm resolution). The deduced structure for pre-mineralized bone fibrils includes features that are not present in RTT: spatially discrete microfibrils. The data are consistent with bone microfibrils similar to pentagonal Smith microfibrils, but are not consistent with the (nondiscrete) quasi-hexagonal microfibrils reported for RTT. These results indicate that collagen fibrils in bone and tendon differ in their internal structure in a manner that allows bone fibrils, but not tendon fibrils, to internally mineralize. In addition, the unique pattern of collagen cross-link types and quantities in mineralized tissues can be can be accounted for, in structural/functional terms, based on a discrete microfibril model.

scholarly journals The safety and efficacy of intra-articular dual molecular weighted hyaluronic acid in the treatment of knee osteoarthritis: the I.D.E.H.A. study

2013 ◽  
Vol 5 (4) ◽  
pp. 33 ◽  
Author(s):  
Xuming Shen ◽  
Romeo Gatti
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Knee Osteoarthritis ◽  
Concomitant Medication ◽  
Therapeutic Effects ◽  
Joint Function ◽  
Beneficial Effects ◽  
The Third ◽  
Lequesne Index ◽  
Concomitant Medications

In clinical practice viscosupplementation with hyaluronic acid (HA) is common for the treatment of degenerative osteoarthritis (OA). Both molecular weight and concentration of HA have significant impact on its rheological properties, which in turn affects its therapeutic effects. The objective of this study is to evaluate the effectiveness of a double HA preparation for the treatment of knee osteoarthritis with respect to pain reduction, joint function improvement and concomitant medication consumption reduction. One thousand and fourteen patients (521 males and 693 females) with a mean age of 62.4 years old, suffering from OA of the knee, were enrolled into this study. All patients received two intra-articular injections one week apart and a third injection one month after the second one. Concomitant medication was recorded and evaluated at follow up visits. Evaluation was performed at baseline, day 30 and day 180, on several parameters: knee pain by visual analog scale (VAS) 0-10 cm, Lequesne Index, and consumption of concomitant medications including non-steroidal anti-inflammatory drugs, analgesics and chondoprotective supplementations. A statistically significant reduction in pain VAS score was recorded at D30 (38.01±17.68; P<0.01) before the third injection, and D180 (25.91±15.33; P<0.01) check-points comparing to baseline (67.12±15.99). Similarly, remarkable reduction in Lequesne Index was shown at D30 (5.91±4.01; P<0.01) in 1214 patients before the third injection, and D180 (3.59±3.45; P<0.01) (with 938 patients) when compared to the baseline (11.60±5.13). Patients also consumed less concomitant medications after the treatment course. The beneficial effects were maintained for up to six months. Intra-articular injection of a double HA preparation of low molecular weight and high molecular weight of different concentrations was well tolerated, and generated satisfactory results in terms of pain control, joint function improvement and concomitant medication reduction for the management of knee OA.

Distribution spaces for hyaluronan and albumin in rat tail tendons

2001 ◽  
Vol 281 (4) ◽  
pp. H1589-H1597 ◽  
Author(s):  
Knut Aukland ◽  
Olav Tenstad ◽  
Helge Wiig
Keyword(s):  
Serum Albumin ◽  
Metabolic Inhibitors ◽  
Free Fluid ◽  
Chemical Binding ◽  
Low Concentration ◽  
Tail Tendon ◽  
Distribution Spaces ◽  
Rat Tail

A low concentration of hyaluronan (HA) in lymph compared with tissue suggests a large bound fraction. To investigate the distribution and mobility of HA and serum albumin (Alb), we eluted the rat tail tendon with a series of l5 successive centrifugations, each preceded by the addition of 0.15 M NaCl (15% of initial wet wt). The eluate concentration fell exponentially versus the accumulated eluate, allowing estimation of the maximal elutable amount (EHA and EAlb). Alb elution was practically complete from a space of ≈28% of wet wt at all centrifugation rates. Twenty percent of HA was elutable at 500 rpm, apparently from the same space as Alb, increasing to 40% at >4,000 rpm. This pattern was not significantly influenced by using 2 M NaCl or by the addition of plasma or metabolic inhibitors. Without prehydration and centrifugation at high revolutions per minute, both Alb and HA concentrations fell rapidly toward zero, presumably in part reflecting mobilization of HA- and Alb-free fluid from the collagen intrafibrillar space (3). We conclude that with prehydration the fibrils swell, increasing the intramolecular spaces to become “penetrable” to HA and allowing removal of HA-containing fluid when the fibrils are compressed by the next centrifugation at high revolutions per minute, increasing EHA from 23 to 45%. Chemical binding presumably explains the unelutable 55% of tendon HA. Intrafibrillar HA may act to stabilize the fibrillar volume.

Autologous Tendons Used as Grafts for Bridging Peripheral Nerve Defects

1999 ◽  
Vol 24 (3) ◽  
pp. 284-290 ◽  
Author(s):  
J. BRANDT ◽  
L. B. DAHLIN ◽  
G. LUNDBORG
Keyword(s):  
Extracellular Matrix ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Repair ◽  
The Third ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Tail Tendon ◽  
Rat Tail

This study was performed to investigate whether autologous collagen and other extracellular matrix components could be used in nerve repair by bridging a 10 mm defect in the rat sciatic nerve. Three models of repair were examined. In the first model, a rat tail tendon was teased and subsequently rolled to form a loose collagen roll which was sutured over the defect. In the second model, an intact tendon was used. In the third model, a teased tendon was pretreated with attachment of nerve segments to each end for 4 weeks before grafting. Both teased and intact tendons supported regeneration, to some extent. Pretreatment resulted in migration of Schwann cells into the graft, and enhanced regeneration.

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