The anabolic steroid nandrolone enhances motor and sensory functional recovery in rat median nerve repair with long interpositional nerve grafts.

BACKGROUND: Recovery from peripheral nerve repair is frequently incomplete. Hence drugs that enhance nerve regeneration are needed clinically. OBJECTIVES: To study the effects of nandrolone decanoate in a model of deficient reinnervation in the rat. METHODS: In 40 rats, a 40-mm segment of the left median nerve was removed and interposed between the stumps of a sectioned right median nerve. Starting 7 days after nerve grafting and continuing over a 6-month period, we administered nandrolone at a dose of 5 mg/kg/wk to half the rats (n = 20). All rats were assessed behaviorally for grasp function and nociceptive recovery for up to 6 months. At final assessment, reinnervated muscles were tested electrophysiologically and weighed. Results were compared between rats that had received versus not received nandrolone and versus 20 nongrafted controls. RESULTS: Rats in the nandrolone group recovered finger flexion faster. At 90 days postsurgery, they had recovered 42% of normal grasp strength versus just 11% in rats grafted but not treated with nandrolone. At 180 days, the average values for grasp strength recovery in the nandrolone and no-nandrolone groups were 40% and 33% of normal values for controls, respectively. At 180 days, finger flexor muscle twitch strength was 16% higher in treated versus nontreated rats. Thresholds for nociception were not detected in either group 90 days after nerve grafting. At 180 days, nociceptive thresholds were significantly lower in the nandrolone group. CONCLUSIONS: Nandrolone decanoate improved functional recovery in a model of deficient reinnervation.

Effect of neurotrophic factor, MDP, on rats’ nerve regeneration

Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.

Effect of neurotrophic factor, MDP, on rats' nerve regeneration.

Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.

Carbaryl poisoning and edrophonium: electrophysiologic changes.

A case of poisoning with the insecticide carbaryl, a cholinesterase inhibitor, was studied using repetitive stimulation and edrophonium administration. Without edrophonium, repetitive stimulation studies were normal. After 5mg of edrophonium was administered intravenously, a 40% decrement was recorded using 3Hz stimulation and an 80% decrement was seen with 30Hz stimulation. It is concluded that edrophonium is useful in testing for poisoning with cholinesterase inhibitors when other electrophysiologic studies are normal. These changes are most likely due to a recently described fast desensitization of the acetylcholine (ACh) receptor induced by high ACh concentrations.

[Polyneuropathy caused by tuberculostatics. Study of motor nerve conduction in 29 patients]. / Polineuropathisa determinadas por tuberculostaticos. Estudo da conducão nervosa motora em 29 pacientes

The electroneurographic study in 29 patients, during treatment with isoniazid for pulmonary tuberculosis in 12 months period is reported. The patients age were between 16 and 70 years. During the study period motor nerve conduction velocity was done every two months in the median, ulnar and peroneal nerves. The statistical analysis in a 6 months period, revealed p greater than 0.05 (nonsignificant) at the median and peroneal nerves, in spite of the lowering of the motor nerve conduction in a 12 months period. The same findings were observed with the ulnar nerve, but p less than 0.01 (significant). It was impossible to establish a correlation between the motor nerve conduction velocities and the clinical findings observed in the patients. This paper, in the author's opinion, shows that the nerve motor conduction technique is worthless in the follow up of isoniazid patients.