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- Dahlin, L B, et al.
(författare)
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Stimulation of nerve regeneration by macrophages in granulation tissue
- 1996
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Ingår i: Restorative Neurology and Neuroscience. - 0922-6028. ; 9:3, s. 9-141
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Tidskriftsartikel (refereegranskat)abstract
- The effects of granulation tissue exposure on regeneration of sensory axons after a test crush lesion in rat sciatic nerves were studied. Chromic catgut threads were applied subcutaneously in the back of rats. Three weeks later the surrounding granulation tissue was isolated and transposed to the sciatic or tibial nerve in the same rat. Immunocytochemical, light and electron microscopic evaluation of the isolated granulation tissue revealed numerous EDI and ED2 positive macrophages. After an additional three weeks the sciatic nerves were crushed and the axonal outgrowth lengths were measured by the pinch reflex test and by neurofilament staining 3 or 6 days later. The regeneration distances in the sciatic nerve exposed to granulation tissue were significantly longer compared with that of nerves to which only subcutaneous tissue was transposed. Thus, the nerve had become conditioned by the transposure of macrophage rich tissue. After the transposure macrophages were present close to the nerve at the time point of the test crush lesion, but no signs of degeneration or inflammation in the endoneurial space were observed. It was also found that the outgrowth lengths in the tibial nerve branch were consistently longer than in the peroneal branch of the sciatic nerve. It is concluded that granulation tissue, containing macrophages, can induce a conditioning effect in the sciatic nerve. We suggest that this effect is related to factors emanating from macrophages in the transposed tissue.
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- Lundborg, G, et al.
(författare)
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Tubular versus conventional repair of median and ulnar nerves in the human forearm : early results from a prospective, randomized, clinical study
- 1997
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Ingår i: The Journal of Hand Surgery. - 0363-5023. ; 22:1, s. 99-106
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Tidskriftsartikel (refereegranskat)abstract
- Injury to a peripheral nerve is followed by local synthesis and release of neurotrophic factors of importance for the regeneration process. This concept was adopted for repair of transected human median and ulnar nerves in the forearm. As an alternative to conventional microsurgical repair of the nerve trunk, silicone tubes of appropriate size were used to enclose the injury zone, intentionally leaving a gap measuring 3-4 mm between the nerve ends inside the tube. The early results from a prospective, randomized, clinical study comparing this principle with conventional microsurgical technique for repair of human median and ulnar nerves, is presented. Eighteen patients (14 men and 4 women), aged 12-72 (mean, 29.5) years, were randomized to either tubulization (11 cases) or conventional microsurgical repair (7 cases). A battery of tests for sensory and motor functions of the hand were carried out at regular intervals for up to 1 year after surgery. The results show no difference between the both techniques, with the exception of perception of touch, which showed a significant difference (p < .05) at the 3-month checkup in favor of the tubulization technique. At re-exploration 11 months after the initial procedure (1 case), the former gap was replaced by regenerated nerve tissue in direct continuity with the proximal and distal parts of the nerve trunk, the exact level of the former injury being impossible to identify. Study data demonstrate an intrinsic capacity of human major nerve trunks to reconstruct themselves in a preformed space when an optimal environment is offered and the surgical trauma is minimized.
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- Miyauchi, Akira, et al.
(författare)
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Role of macrophages in the stimulation and regeneration of sensory nerves by transposed granulation tissue and temporal aspects of the response
- 1997
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - 0284-4311. ; 31:1, s. 17-23
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Tidskriftsartikel (refereegranskat)abstract
- Application of granulation tissue, which is rich in macrophages, to a peripheral nerve induces a conditioning effect, in that it enhances the regeneration capability of peripheral nerves after a test crush lesion. The temporal aspects of this response and the role of macrophages and interleukin-1 beta (IL-1 beta) were studied in the sciatic nerves of 71 rats. Granulation tissue was implanted close to the sciatic nerve and test crush lesions were applied after various periods of time (0-21 days). Regeneration was evaluated after an additional two, three, four, or six days. Regeneration distances were longer in granulation-treated nerves than in nerves treated with subcutaneous tissue. Furthermore, in animals in which the test crush lesion was made at the same time as the granulation tissue was implanted (n = 6), regeneration distances were longer, 8.1 (0.8) mm compared with 7.2 (0.6), than those in which the crush was made after conditioning intervals of 3 (n = 6, 7.6 (0.4) compared with 6.9 (0.4), p = 0.03); 7 (n = 6, 7.4 (0.4) compared with 6.6 (0.1), p = 0.03); and 21 days [(n = 8, 7.2 (0.6) compared with 6.4 (0.5)]. Inactivation of the granulation tissue by freezing suppressed the conditioning effect. There were numerous ED1 and ED2 positive macrophages as well as positive staining for IL-1 beta in the granulation tissue on day 0. Positive staining for IL-1 beta was also seen in nerve fibres as well as in non-neuronal cells after a conditioning interval. The results suggest that regeneration is stimulated by factors released from the cells of the granulation tissue, and that the amount of factors released or the responsiveness of the regenerating nerve change during the conditioning interval.
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