Search results

Resistance to activated protein C (APC) is the most prevalent inherited cause of venous thrombosis. The APC resistance phenotype is associated with a single point mutation in the factor V gene, changing Arg506 in the APC cleavage site to a Gln. We have investigated 50 Swedish families with inherited APC resistance for this mutation and found it to be present in 47 of them. Perfect cosegregation be

In the nerve regeneration silicone chamber model, the regenerate which forms across a 10-mm gap between proximal and distal nerve stumps is a monofascicular structure with an outer perineurial-like cell sheath. Recent work has provided indications that the geometry of the regenerate within a silicone chamber can be altered by experimental modifications of the chamber matrix. In the present study w

Gore-tex chambers were used to bridge a 6 mm gap between the proximal and distal nerve stumps of a rat sciatic nerve. The wall structure of these chambers is characterized by "nodes" interconnected by smaller fibrils. Chambers with internodal distances of 5, 10 and 30 microns were used. Some 30 microns chambers were coated from the outside with Gore-tex (0.2 micron internodal distance) and others

When silicone regeneration chambers are implanted empty, axonal regeneration fails if the interstump gap length is greater than 10 mm. Previous experiments using the 10-mm gap model demonstrated that regeneration success correlated with the dimension and/or consistency of the naturally formed acellular fibrin matrix. Both spatial and temporal parameters of regeneration could be stimulated through

We have compared the anatomic and functional regeneration of a transected sciatic nerve following regrowth from its proximal stump through either preformed empty mesothelial chambers or autologous nerve grafts bridging a 10 mm gap. Within the mesothelial chambers an organized multifascicular nerve trunk forms between the proximal and distal stumps. After 3 months, distal segment cross sections fro

In the present study, neuronal and Schwann cell marker proteins were used to biochemically characterize the spatiotemporal progress of degeneration/regeneration in the silicone chamber model for nerve regeneration. Rat sciatic nerves were transected and the proximal and distal stumps were inserted into a bridging silicone chamber with a 10-mm interstump gap. Using dot immunobinding assays, S-100 p

Experiments were performed on chloralose anaesthetized cats. A 2-cm segment of the proximal duodenum was isolated between two luminally situated balloons and perfused with isotonic saline containing [14C]-PEG 4000 as a non-absorbable marker. The perfusate was analysed with regard to alkalinity (back titration) and concentration of marker (liquid scintillation). Net alkalinization and net fluid tra

In the present study the inflammatory response was quantitatively evaluated during peripheral nerve regeneration. The fluid from silicone nerve regeneration chambers, inserted in rats, was collected during the early period of regeneration of transected sciatic nerves (6 h-7 d) and analysed with respect to inflammatory cells and mediators (leukotriene B4, LTB4, and interleukin-1 alpha, IL-1 alpha).

The possibility that collateral sprouting could occur from intact axons in an undamaged sciatic nerve was studied in the rat by suturing either a 7-day predegenerated or a fresh nerve segment in an end-to-side fashion to the sciatic nerve proper. Following a 14- or 35-day recovery period, the pinch reflex test was performed on the transplanted segment to demonstrate the presence of sensory axons.

Target-derived neurotrophic factors are of basic importance for survival of neurons. In the normal state, such neurotrophic factors, synthesized by the target tissues, are taken up by nerve terminals and transported by retrograde axonal transport in axons to the nerve-cell bodies to maintain their viability. After nerve injury, neurotrophic factors are synthesized by non-neuronal cells (Schwann ce

The silicone chamber model for nerve regeneration is suitable to test the effects of exogenous agents or surgical manipulations on nerve regeneration. The total 16-day regeneration period used in this model makes it possible to analyze the effects of certain manipulations on the sequential advancement of the individual cellular components (circumferential perineurial-like cells, vessels, Schwann c

Preformed, autologous mesothelial chambers were utilized to study axonal growth following selective predegeneration of the distal nerve stump and/or preconditioning of the proximal nerve stump. The left and/or right sciatic nerve of rats was exposed and transected in the thigh. Two weeks after transection, the left proximal nerve stump was cross-anastomosed with the right distal nerve stump by usi

Peripheral neuropathy represents a well-known complication from long-term exposure to vibration. In the present study an experimental model is presented with the purpose of analyzing the formation of intraneural edema following vibration exposure. Vibration (82 Hz, peak-to-peak amplitude 0.21 mm) was induced in the hind limb of rats by the use of vibrating electric motors during 4 h/d for 5 d. Tra

An experimental model is presented for studying axonal growth after experimental hyperthyroidism and hypothyroidism. The left sciatic nerve of the rat was transected and transposed to the back. The proximal nerve stump was inserted into a 50-mm-long mesothelial chamber leaving the distal end of the chamber open. Different groups of young adult rats were given daily injections of thyroxine (10 micr

Morphological studies have indicated that proximal nerve ends of transected rat sciatic nerves regenerating into preformed mesothelial chambers show a different organization as compared to neuromas developed in contact with a muscle fascia. We have studied the physiological properties of nerve fibres arising from these types of preparations with reference to ongoing activity, response to mechanica

Effects of graded compression on nerve function were analyzed in order to evaluate the relative importance of pressure level and duration of compression for functional deterioration. The pressure was applied by means of a small inflatable cuff. The effects of two pressure levels, i.e., 80 mm Hg applied for 2 hr or 400 mm Hg applied for 15 min, were studied in rabbit tibial nerves. The lower pressu

The mechanisms influencing regeneration of peripheral nerves are incompletely known, but growth factors are supposed to play a key role. In the present study, we demonstrate, with the aid of immunohistochemical methods, that somatomedin C (Sm-C/insulin-like growth factor I/IGF-I) rapidly increased from low to high concentrations, reaching peak values in 2 weeks, in regenerating sciatic nerves of a

In 1944 Weiss & Taylor presented experimental evidence against "neurotropism" in nerve regeneration. We used a silicone Y-chamber system to repeat some of those experiments. The proximal stump of transected rat sciatic nerve was introduced into the proximal inlet of the Y. One of the distal outlets was left empty, plugged or occupied by a tendon graft, the other outlet being occupied by a nerv

An experimental model is presented for studying nerve regeneration over gaps of various lengths between the both ends of a severed nerve. After transferring left and right sciatic nerves of rat to the back, the gap between the two nerve ends could be bridged by a preformed, tube-shaped mesothelial chamber of a desired length. When the gap length was 10 mm or less, a well developed nerve structure