Effect of hypoxia/reoxygenation on the cytokine-induced production of nitric oxide and superoxide anion in cultured osteoarthritic synoviocytes

SummaryObjectiveHypoxia/reoxygenation (H/R) is an important feature in the osteoarthritis (OA) physiopathology. Nitric oxide (NO) is a significant proinflammatory mediator in the inflamed synovium. The purpose of this study was to investigate the effects of H/R on inducible NO synthase (iNOS) activity and expression in OA synoviocytes. In addition we studied the relationship between nitrosative stress and NADPH oxidase (NOX) in such conditions.MethodsHuman cultured synoviocytes from OA patients were treated for 24 h with interleukin 1-β (IL-1β), tumour necrosis factor α (TNF-α) or neither; for the last 6 h, they were submitted to either normoxia or three periods of 1-h of hypoxia followed by 1-h of reoxygenation. NO metabolism (iNOS expression, nitrite and peroxynitrite measurements) was investigated. Furthermore, superoxide anion O2− production, NOX subunit expression and nitrosylation were also assessed.ResultsiNOS expression and nitrite (but not peroxynitrite) production were significantly increased under H/R conditions when compared with to normoxia (P < 0.05). H/R conditions decreased O2− production from ∼0.20 to ∼0.12 nmol min−1 mg proteins−1 (P < 0.05), while NOXs' subunit expression and p47-phox phosphorylation were increased. NOXs and p47-phox were dramatically nitrosylated under H/R conditions (P < 0.05 vs normoxia). Using NOS inhibitors under H/R conditions, p47-phox nitrosylation was prevented and O2− production was restored at normoxic levels (0.21 nmol min−1 mg of proteins−1).ConclusionsOur results provide evidence for an up-regulation of iNOS activity in OA synoviocytes under H/R conditions, associated to a down-regulation of NOX activity through nitrosylation. These findings highlight the importance of radical production to OA pathogenesis, and appraise the metabolic modifications of synovial cells under hypoxia

Comparison of Patient and Surgeon Expectations of Total Hip Arthroplasty

OBJECTIVES: Analysis of discrepancies between patient and surgeon expectations before total hip arthroplasty (THA) should enable a better understanding of motives of dissatisfaction about surgery, but this question has been seldom studied. Our objectives were to compare surgeons' and patients' expectations before THA, and to study factors which affected surgeon-patient agreement. METHODS: 132 adults (mean age 62.8+/-13.7 years, 52% men) on waiting list for THA in three tertiary care centres and their 16 surgeons were interviewed to assess their expectations using the Hospital for Special Surgery Total Hip Replacement Expectations Survey (range 0-100). Patients' and surgeons' answers were compared, for the total score and for the score of each item. Univariate analyses tested the effect of patients' characteristics on surgeons' and patients' expectations separately, and on surgeon-patient differences. RESULTS: Surgeon and patient expectations' mean scores were high (respectively 90.9+/-11.1 and 90.0+/-11.6 over 100). Surgeons' and patients' expectations showed no systematic difference, but there was little agreement on Bland and Altman graph and correlation coefficient was low. Patients had higher expectations than surgeons for sports. Patients rated their expectations according to trust in physician and mental quality of life, surgeons considered disability. More disabled patients and patients from a low-income professional category were often "more optimistic" than their surgeons. CONCLUSION: Surgeons and patients often do not agree on what to expect from THA. More disabled patients expect better outcomes than their surgeons

[Electromyographic study of stretch reflexes in the normal and prosthetic hip].

International audienceChanges due to joint replacement and capsulectomy do not appear to affect the stretch reflexes of the hip joint

Surgical management of pelvic primary bone tumors involving the sacroiliac joint

SummaryIntroductionPelvic primary malignant bone tumours, especially when involving the sacroiliac joint are difficult to treat. Abdominoperineal amputations are today used, only in life-threatening situations.HypothesisA precisely planed surgical technique can save the affected extremity without compromising the resection quality and subsequent patient survival.ObjectiveTo assess the procedures used for resection and reconstruction of bone tumours invading the sacroiliac joint as well as their effects on cancer outcome and functional results.Materials and methodsThis is a continuous and retrospective analysis of 24 patients treated between 1986 and 2003. Six tumours affected the sacral body and 18 tumours involved the wing of the ilium. The joint articular surface was invaded in only six cases. Seventeen patients received neoadjuvant chemotherapy. The procedure was performed through an enlarged iliac crest incision, giving access to two sections of the pelvic ring. Six cases required neurological sacrifice. Initial tumour grading was based on the Enneking classification, and the functional results, on the Musculoskeletal Tumour Society (MSTS) scoring system.ResultsThe average operation lasted 5.27hours. Reconstruction was performed with bone autograft and instrumentation. Resection was large with adequate margins 11 times, marginal 12 times, and contaminated once. Average follow-up was 4.77 years. The 5-year survival rate was 50%. Twelve patients either died from their disease or were in the metastatic stage at final follow-up. Survival was linked to the quality of resection and initial tumour staging. Hemisacrectomy did not affect patient survival. Local recurrences had a poor prognosis with eight cases of secondary metastases out of 11. Bone healing occurred in 13 patients, 10 of whom survived. Of the 12 patients who survived and were in complete remission at final follow-up, the average MSTS score was 61%. The score was at 38.6% in cases involving neurological sacrifice, and at 77.1% for the rest of the group. It was at 64% in healed cases and 13% in nonunion cases.DiscussionThe survival of patients presenting with a sacroiliac joint tumour is substantially related to both tumour histology and resection quality. Local recurrences carry a poor prognosis with a high rate of secondary metastatic dissemination. In situations where disease control can be achieved, the proposed method of reconstruction allows, satisfactory bone healing and fair functional recovery, provided no major neurological sacrifice has taken place.Level of evidence: level IV: Retrospective Therapeutic Study