BackgroundExtracellular-signal regulated kinase (ERK1/2) is activated by nerve damage and its activation precedes survival and proliferation of Schwann cells. In contrast, activation of caspase 3, a cysteine protease, is considered as a marker for apoptosis in Schwann cells. In the present study, axonal outgrowth, activation of ERK1/2 by phosphorylation (p-ERK 1/2 ) and immunoreactivity of cleaved caspase 3 were examined after immediate, delayed, or no repair of transected rat sciatic nerves.ResultsAxonal outgrowth, detected by neurofilament staining, was longer after immediate repair than after either the delayed or no repair conditions. Immediate repair also showed a higher expression of p-ERK 1/2 and a lower number of cleaved caspase 3 stained Schwann cells than after delayed nerve repair. If the transected nerve was not repaired a lower level of p-ERK 1/2 was found than in either the immediate or delayed repair conditions. Axonal outgrowth correlated to p-ERK 1/2, but not clearly with cleaved caspase 3. Contact with regenerating axons affected Schwann cells with respect to p-ERK 1/2 and cleaved caspase 3 after immediate nerve repair only.ConclusionThe decreased regenerative capacity that has historically been observed after delayed nerve repair may be related to impaired activation of Schwann cells and increased Schwann cell death. Outgrowing axons influence ERK 1/2 activation and apoptosis of Schwann cells.

Background:Shoulder rotational muscles act as dynamic stabilizers of the glenohumeral joint, and the recovery of muscle strength plays an important role in stabilizing the joint during postoperative rehabilitation. However, temporal changes in muscle strength after arthroscopic Bankart repair have not been clarified.Purpose:To better understand the temporal recovery of shoulder rotational muscle strength after arthroscopic Bankart repair.Study Design:Case series; Level of evidence, 4.Methods:Isokinetic concentric shoulder rotational muscle strength was evaluated in 50 patients who were diagnosed with recurrent dislocations of the glenohumeral joint and treated with arthroscopic Bankart repair.Results:The mean peak torque/weight and total work were reduced significantly at 1.5 months after surgery (P < .0001) and returned to preoperative levels by 6 months for external rotation and 4.5 months for internal rotation. The contralateral peak torque ratios reached preoperative levels by 6 months after surgery. The ipsilateral peak torque ratios were reduced between 1.5 and 3 months after surgery and returned to preoperative levels at 6 months for external rotation and 4.5 months for internal rotation.Conclusion:Isokinetic shoulder rotational muscle strength after arthroscopic Bankart repair recovered to preoperative levels by 6 months for external rotation and 4.5 months for internal rotation.

Introduction The relation between radiological abnormalities on lumbar spine and low back pain (LBP) has been debated, presumably because of potential biases related to heterogeneity in selection of the subjects, radiological abnormalities at entry, or its cross-sectional observation in nature. Therefore, the aim of this study of a selected population of asymptomatic Japanese Self Defense Forces (JSDF) young adults male with normal lumbar radiographs was to investigate the incidence of newly developed lumbar degenerative changes at middle age and to study their association to LBP. Subjects and methods In 1990, 84 JSDF male military servicemen aged 18 years, without a history of LBP and radiological abnormal findings, were enrolled. After 20 years, 84 subjects were underwent repeated X-ray and completed questionnaires on current LBP and lifestyle factors. Results The prevalence of LBP was demonstrated 59 %, with 85 % of them showing mild pain. Analysis of lumbar radiographs revealed that 48 % had normal findings and 52 % had degenerative changes. The association between LBP and life style factors was not demonstrated. Lumbar spine in subjects with LBP was more degenerated than in those without. Although disc space narrowing and LBP did not achieve a statistical significance, a significant correlation existed between vertebral osteophyte and LBP in univariate and multivariate analysis (OR 3.0;). Discussion and conclusionsThis longitudinal study demonstrated the significant association between vertebral osteophyte and incidence of mild LBP in initially asymptomatic and radiologically normal subjects. These data provide the additional information concerning the pathology of LBP, but further study is needed to clarify the clinical relevance.

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