| 1. |
- Bontioti, Eleana, et al.
(författare)
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End-to-side nerve repair in the upper extremity of rat.
- 2005
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1085-9489 .- 1529-8027. ; 10:1, s. 58-68
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Tidskriftsartikel (refereegranskat)abstract
- The end-to-side nerve-repair technique, i.e., when the distal end of an injured nerve is attached end-to-side to an intact nerve trunk in an attempt to attract nerve fibers by collateral sprouting, has been used clinically. The technique has, however, been questioned. The aim of the present study was to investigate end-to-side repair in the upper extremity of rats with emphasis on functional recovery, source, type, and extent of regenerating fibers. End-to-side repair was used in the upper limb, and the radial or both median/ulnar nerves were attached end-to-side to the musculocutaneous nerve. Pawprints and tetanic muscle force were used to evaluate functional recovery during a 6-month recovery period, and double retrograde labeling was used to detect the source of the regenerated nerve fibers. The pawprints showed that, in end-to-side repair of either one or two recipient nerves, there was a recovery of toe spreading to 60-72% of the preoperative value (lowest value around 47%). Electrical stimulation of the end-to-side attached radial or median/ulnar nerves 6 months after repair resulted in contraction of muscles in the forearm innervated by these nerves (median tetanic muscle force up to 70% of the contralateral side). Retrograde labeling showed that both myelinated (morphometry) sensory and motor axons were recruited to the end-to-side attached nerve and that these axons emerged from the motor and sensory neuronal pool of the brachial plexus. Double retrograde labeling indicated that collateral sprouting was one mechanism by which regeneration occurred. We also found that two recipient nerves could be supported from a single donor nerve. Our results suggest that end-to-side repair may be one alternative to reconstruct a brachial plexus injury when no proximal nerve end is available.
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| 2. |
- Bontioti, Eleana N, et al.
(författare)
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Regeneration and functional recovery in the upper extremity of rats after various types of nerve injuries.
- 2003
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1085-9489 .- 1529-8027. ; 8:3, s. 159-168
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to establish an accurate, reproducible, and simple method to evaluate functional recovery after different types of nerve injuries to the brachial plexus of rats. To that end, pawprints, measured as distance between the first and fourth and second and third digits, were used for evaluation of injuries including crush injury, transection/repair, or graft repair of the median, ulnar, and radial nerves. Immunocytochemistry of the C-terminal flanking peptide of neuropeptide Y (CPON) and neurofilaments was used to investigate the cell body response and axonal outgrowth, respectively. Functional recovery was dependent on the severity as well as on the level of the lesion. Neither a single injury to the median nerve nor an injury to the ulnar nerve affected the pawprint, while an injury to both these nerves or a single injury to the radial nerve caused impairment of pawprints. There was a rapid recovery after crush injury to these nerves compared to previous reports of a similar injury to the sciatic nerve. The pattern of axonal outgrowth was related to the severity of the lesion. A conditioning lesion, i.e., an initial lesion of the same nerve preceding a test injury by a few days, of both motor/sensory fibers led to a quicker functional recovery. Surprisingly, conditioning of only sensory fibers had nearly the same effect. The cell body response was dependent on the level of the nerve lesion. The upper extremity of rats might be useful to evaluate the effects of new repair methods after nerve injuries using functional evaluation with pawprints as a simple and accurate method
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| 3. |
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| 4. |
- Haapaniemi, T, et al.
(författare)
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Functional evaluation after rat sciatic nerve injury followed by hyperbaric oxygen treatment
- 2002
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1085-9489 .- 1529-8027. ; 7:3, s. 149-154
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Tidskriftsartikel (refereegranskat)abstract
- Previous experimental studies have shown positive effects of hyperbaric oxygen treatment in the early regeneration phase in the first few days following a nerve injury. In this study, functional effects of hyperbaric oxygen treatment were studied in 2 series of rats after an injury to the sciatic nerve - a standardized crush injury and nerve transection and repair, respectively. Postoperatively the animals were treated with 100% oxygen at 2.5 atmospheres absolute pressure for 90 minutes and the treatment was employed twice daily for 7 days. The animals were evaluated with walking track analysis up to twice weekly. The experiments were terminated after 90 days when the tetanic force was measured in the tibial anterior and gastrocnemius muscles. No statistically significant differences were found in either of these tests. It is concluded that hyperbaric oxygen treatment, given in accordance with clinical protocols used in limb crush injuries and other peripheral conditions, was not effective in the restoration of gait or the muscular strength after 90 days in rats after these nerve injuries. This study does not support nerve crush injury or nerve transection and repair as indications for hyperbaric oxygen treatment.
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| 5. |
- Kvist, Martin, et al.
(författare)
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Costimulation blockade in transplantation of nerve allografts: long-term effects.
- 2008
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1529-8027 .- 1085-9489. ; 13:3, s. 200-207
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Tidskriftsartikel (refereegranskat)abstract
- Costimulation blockade can prevent rejection of nerve allografts in short-term studies. We tested if costimulation blockade also prevented rejection of nerve allografts in long-term experiments, thereby improving functional recovery. A 7-mm sciatic nerve defect in C57/BL6 mice was bridged either by nerve allografts from Balb/C mice or by isogenic nerve grafts (isografts) from C57/BL6 mice. Costimulation blockade in the form of a triple treatment with anti-LFA-1, anti-CD40L, and CTLA4Ig was given at post-operative days 0, 2, 4, and 6 (intraperitoneal). Control mice (placebo; allografts) with nerve grafts were treated with isotype antibodies during the same time period. After 49 days, tetanic muscle force, wet weight of gastrocnemius muscle, histology, and morphometry in the tibial nerve were evaluated. Costimulation blockade diminished rejection of the nerve allografts. Axons bridged the graft. Treatment increased wet weight of the gastrocnemius muscle and resulted in a higher mean myelin area/nerve fiber in the tibial nerve distal to the nerve grafts. Tetanic muscle force and number of axons in tibial nerve showed no differences between groups. We conclude that rejection is suppressed by costimulation blockade. Treatment improves recovery of target muscle and myelination after nerve allografting.
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| 6. |
- Kvist, Martin, et al.
(författare)
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Effects of FK506 on regeneration and macrophages in injured rat sciatic nerve.
- 2003
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1085-9489 .- 1529-8027. ; 8:4, s. 251-259
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Tidskriftsartikel (refereegranskat)abstract
- Effects of FK506 [5.0 mg/kg body weight (BW), subcutaneous, daily] on nerve regeneration and presence of macrophages in lesioned rat sciatic nerves were studied. Models of autologous nerve graft or a nerve crush lesion were used and regeneration was evaluated by immunocytochemistry (also used to detect ED1/ED2 macrophages) and sensory pinch reflex test, respectively. Treatment with FK506 did not increase regeneration distance or regeneration rate in the autologous nerve grafts. However, regeneration distances after nerve crush were significantly longer following treatment with FK506. The number of macrophages (ED1/ED2) in nerve grafts increased over time, but treatment with FK506 had limited effects only in the presence of ED2 macrophages. Present and previously published studies may imply that there is a time-related and type-of-injury-related profile of FK506's pro-regenerative effect.
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| 7. |
- Kvist, Martin, et al.
(författare)
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Immunomodulation by costimulation blockade inhibits rejection of nerve allografts
- 2007
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1085-9489 .- 1529-8027. ; 12:2, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate if costimulation blockade could be used to modulate the immune response, to prevent rejection, and to stimulate regeneration into nerve allografts. Nerve allografts from Balb/C mice, and isogenic nerve grafts (isografts) from C57/BL6 mice, were used to bridge a 7-mm gap of the sciatic nerve in C57/BL6 mice. Allograft recipients were treated with either a triple treatment with anti-lymphocyte function antigen-1 (anti-LFA), anti-CD40 ligand (anti-CD40L), and cytotoxic T-lymphocyte antigen 4 immunoglobulin (anti-CTLA4Ig) or isotype antibodies (placebo) at postoperative days 0, 2, 4, and 6 (intraperitoneal). After 5 or 9 days, the nerve grafts, together with the proximal and the distal nerve segments, were evaluated by histology and immunocytochemistry for inflammatory cells [CD4-positive (CD4+) and CD8-positive (CD8+) staining cells] and axonal outgrowth (neurofilaments). The immune response was inhibited by costimulation blockade with less extensive inflammation and a lower number of CD4+ staining cells in triple-treated allografts at 9 days. The regeneration rate was significantly faster in isografts (0.75 mm/day) compared with allografts with placebo treatment (0.39 mm/day), but not when compared with triple-treated allografts (0.49 mm/day). At 9 days, the axons were significantly longer in nerve isografts than in nerve allografts, irrespective of treatment. Hence, costimulation blockade neither increased the regeneration rate nor the outgrowth length in triple-treated allografts. We conclude that costimulation blockade inhibits the immune response in nerve allografts without deterring early axonal outgrowth.
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| 8. |
- Lundborg, Göran
(författare)
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Richard P. Bunge memorial lecture. Nerve injury and repair--a challenge to the plastic brain.
- 2003
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Ingår i: Journal of the Peripheral Nervous System. - : Wiley. - 1085-9489 .- 1529-8027. ; 8:4, s. 209-226
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Tidskriftsartikel (refereegranskat)abstract
- Repair and reconstruction of major nerve trunks in the upper extremity is a very challenging surgical problem. Today, there is no surgical repair technique that can assure recovery of tactile discrimination in the hand of an adult patient following nerve repair. In contrast, young individuals usually attain a complete recovery of functional sensibility. The outcome from nerve repair depends mainly on central nervous system factors including functional cortical reorganizational processes caused by misdirection in axonal outgrowth. Deafferentation due to local anesthetic block, amputation or nerve transection in the upper extremity leads to very rapid cortical synaptic remodeling, resulting in a distorted cortical hand representation as well as in enlarged and overlapping cortical receptive fields. Sensory relearning programs are aimed at refinement of these receptive fields to normalize the distorted hand map and improve processing at a high-order cortical level in the context of the 'new language spoken by the hand'. As peripheral nerve repair techniques cannot be further refined, there is a need for new and improved strategies for sensory relearning following nerve repair. We propose the utilization of multimodal capacity of the brain, using another sense (hearing) to substitute for lost hand sensation and to provide an alternate sensory input from the hand early after transection. The purpose was to modulate cortical reorganizations due to deafferentation to preserve cortical hand representation. Preliminary results from a prospective clinical randomized study indicate that the use of a Sensor Glove System, which stereophonically transposes the friction sound elicited by active touch, results in improved recovery of tactile discrimination in the nerve-injured hand. Future strategies for treatment of nerve injuries should promote cellular methods to minimize post-traumatic nerve cell death and to improve axonal outgrowth rate and orientation, but high on the agenda are new strategies for refined sensory relearning following nerve repair.
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| 10. |
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