| 1. |
- Danielsen, Nils, et al.
(författare)
-
Inflammatory cells and mediators in the silicone chamber model for nerve regeneration
- 1993
-
Ingår i: Biomaterials. - 0142-9612. ; 14:15, s. 5-1180
-
Tidskriftsartikel (refereegranskat)abstract
- 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). Leucocytes were detected during the entire period (up to 7 d after implantation). The highest concentration was detected after 24 h. PMNG (polymorphonuclear granulocyte) was the predominant cell type in the chamber fluid during the initial 5d of regeneration. Analysis of the concentration of LTB4 demonstrated two peaks (at 24 h and 5 d). The IL-1 alpha concentration displayed an early and relatively smaller peak after 24 h and a second and much larger peak after 7 d, concomitant with an increase of the number of mononuclear cells.
|
|
| 2. |
- Danielsen, Nils, et al.
(författare)
-
The effects of delayed nerve repair on nerve regeneration in a silicone chamber model
- 1994
-
Ingår i: Restorative Neurology and Neuroscience. - 0922-6028. ; 6:4, s. 317-322
-
Tidskriftsartikel (refereegranskat)abstract
- 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 cells, axons, and myelin) into the chamber fibrin matrix. In the present study we compared the effects on cellular migration of a 7 day delayed chamber repair vs. chamber repair immediately after transection (control chambers) of the rat sciatic nerve. Regeneration was evaluated with light and electron microscopic techniques. Chambers implanted after a delay of 7 days had a statistically significant more advanced migration of vessels, Schwann cells, and axons from the proximal nerve stump and also a significantly increased vascular density as compared to control chambers. We conclude that a 7 day delayed nerve repair stimulates nerve regeneration in this specific silicone chamber model.
|
|
| 3. |
- Lundborg, G, et al.
(författare)
-
Trophism, tropism, and specificity in nerve regeneration
- 1994
-
Ingår i: Journal of Reconstructive Microsurgery. - : Georg Thieme Verlag KG. - 0743-684X .- 1098-8947. ; 10:5, s. 54-345
-
Tidskriftsartikel (refereegranskat)abstract
- 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 cells and fibroblasts) in the nerve trunk, thereby supporting the outgrowth of axons. Neurite-outgrowth-promoting factors on cell surfaces (cell adhesion molecules, "recognition molecules") or in the extracellular matrix promote extension of the axons by providing an appropriate "adhesiveness" in the substrate. Both neurotrophic and neurite-outgrowth-promoting factors are essential for axonal growth after injury. Specificity in end-organ reinnervation is a complex phenomenon which may be based on physical factors at the zone of injury, as well as on molecular interaction between axons and substrate cells along the pathways and at the target level. Such processes may include molecular recognition of appropriate axons and maintenance of such axons by trophic mechanisms, as well as the pruning of inappropriate axons. The ultimate errors in target reinnervation are reflected in a cortical re-organization in the somatosensory cortex. The capacity of the brain to "reprogram" itself and adapt to this functional re-organization is critical for the ultimate recovery of functional sensory/motor function after nerve injuries.
|
|
| 4. |
- Lundborg, G, et al.
(författare)
-
Tubular repair of the median nerve in the human forearm. Preliminary findings
- 1994
-
Ingår i: Journal of Hand Surgery: European Volume. - 0266-7681. ; 19:3, s. 273-276
-
Tidskriftsartikel (refereegranskat)abstract
- Transected median nerves in the forearm of two male patients, 12 and 21 years of age, were treated with a chamber technique leaving a 3 to 5 mm gap between the nerve ends. The nerve ends were enclosed in a silicone tube of such a dimension that would not cause compression of the nerve. Post-operative examination including sensory evaluation and assessment of muscle contraction force was carried out after 3 years. In both cases there was excellent motor recovery of the thenar muscles. Outgrowth of sensory fibres was remarkably fast, resulting ultimately in functional sensibility allowing almost normal hand function. 2PD was < or = 6 mm (12-year-old patient) and 8 to 10 mm (21-year-old patient) respectively. In one case the silicone tube was re-explored because of minor local discomfort 2 years after the repair. The former gap was bridged by a smooth continuous nerve-like structure of the same diameter as the adjacent nerve trunk and with no signs of neuroma formation or compression of the nerve.
|
|
| 5. |
- Lundborg, G, et al.
(författare)
-
Ulnar nerve repair by the silicone chamber technique. Case report
- 1991
-
Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - 0284-4311. ; 25:1, s. 79-82
-
Tidskriftsartikel (refereegranskat)abstract
- The ulnar nerve of a 21-year old man was repaired at the wrist by a silicone chamber technique 10 days after a traumatic transection. A 3 mm gap was left between the nerve ends inside the chamber. At follow-up three years later, motor and sensory recovery was excellent. At exploration at that time a macroscopically normal nerve was found in the tube.
|
|
| 6. |
- Shyu, B C, et al.
(författare)
-
Effects of sympathetic stimulation on C-fibre response after peripheral nerve compression : an experimental study in the rabbit common peroneal nerve
- 1990
-
Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 140:2, s. 43-237
-
Tidskriftsartikel (refereegranskat)abstract
- Non-myelinated C-fibre responses during sympathetic trunk stimulation were studied in rabbit common peroneal nerve 2 weeks after the nerve had been subjected to compression at 400 mmHg for 30 min. Our previous studies have demonstrated that during sympathetic trunk stimulation the compound action potential of uninjured somatic C-fibres is characterized by a reduced amplitude and an increased latency. In the present study, nerve compression changed the C-fibre response to sympathetic stimulation. Three out of eight nerves reacted to nerve compression by increased C-fibre compound action potential amplitude in response to sympathetic stimulation. In three other rabbits with compressed nerves the C-fibre action potential amplitude was unchanged, and in the remaining two rabbits the action potential amplitude was decreased during sympathetic stimulation. The action potential latency increased in all tested compressed C-fibres. The phenomenon of increased C-fibre amplitude during sympathetic activation has not been observed in uninjured nerves. As in uninjured nerves, noradrenaline infusion produced an increased C-fibre action potential amplitude and latency in six animals. Sympathetic stimulation did not affect the A-fibre response. These results indicate that sympathetic activity influences the conduction properties in C-fibres of somatic origin and that the response can be changed after a nerve injury. The findings may be of importance for the understanding of pain aggravation in different types of nerve injuries during increased sympathetic activity.
|
|
