[Objective]To investigate whether fibroblasts from malignant bone tumor could support osteoclast differentiation and bone resorption.[Method]Fibroblasts isolated from 8 fresh tumor samples were cultured in vitro.At passage two,part of these fibroblasts were co-cultured with peripheral blood monocytes.M-CSF,OPG and neutralizing anti-TNF-? antibody was added to the culture respectively.A Transwells system was also applied to observe the secretion of solvable factors in fibroblasts.At day 1,day 14 and day 21,the cultures on coverslips and bone slices were stopped and examined for the formation of tartrate resistant acid phosphatase(TRAP)positive multmucleated cells(MNCs)and lacuna resorption pits respectively.The number of lacuna resorption pits on bone slices,which was a marker of OC activity,was compared between the groups.Another part of the fibroblasts were cultured alone,and RT-PCR was performed to investigate the expression of RANKL and TNF-? mRNA in the fibroblasts.[Result]TRAP positive MNCs and lacuna pits were observed in the co-culture group in the presence of M-CSF,but not in the absence of M-CSE.It was also the case in the Transwell group,even though the number of lacuna pits was resuced.OPG completely inhibited the formation of TRAP positive MNCs and lacuna pits,while anti-TNF-? had not inhibiting effect on this process.RT-PCR results showed that both RANKL and TNF-? mRNA were positive in all the fibroblast involved.[Conclusion]In the presence of M-CSF,fibroblasts from malignant bone tumor are capable of supporting osteoclast formation and activity through expression of RANKL.

Objective To investigate the clinical effect of arthroscopic anterior cruciate ligament(ACL) reconstruction using autologous multi-strands of hamstring tendon.Method From May 2002 to Dec.2006,arthroscopic reconstruction of the anterior cruciate ligament using multi-strands of hamstring tendon was performed on 39 patients.Among them,28 cases were followed up for 7 to 48 months(average 13.5±2.3 months).Result The median Lysholm knee score was improved from 47.3±3.6 to 91.3±2.9 after operation.Conclusion Arthruscopic reconstruction of the anterior cruciate ligament using muhi-strands of hamstring tendons is a good alternative method with minimal invasion and convenient tendon harvesting and fewer complication and reliable clinical effect.

Objective:To explore the changes of dynamic cerebral autoregulation ability in pilots exposed to acute positive acceleration(+ Gz) by transcranial Doppler combined with beat-to-beat blood pressure.Methods:A total of 26 pilots enrolled in the + 8Gz manned centrifuge trial at the Air Force Medical Center, Air Force Medical University from June to October 2022 were prospectively included. Blood pressure and heart rate were monitored in the resting state before the trial and within 5 min after centrifugation. Transcranial Doppler combined with noninvasive continuous beat-to-beat blood pressure monitor were used to detect bilateral middle cerebral artery blood flow velocity and beat-to-beat pulse pressure respectively. The transfer function analysis was applied to derive the parameters of cerebral blood flow autoregulation in each frequency band from 0.02 to 0.50 Hz, and the phase, gain and coherence were calculated. The above parameters were compared between resting state and after acute + 8Gz positive acceleration exposure.Results:Compared with the resting state, in all of the 26 pilots after acute + 8Gz positive acceleration exposure, the systolic and diastolic blood pressure and heart rate increased significantly ( P<0.001), the phase significantly increased and the gain significantly decreased in the ultra-low frequency band (0.02-0.07 Hz) ( P<0.05); whereas there were no statistical differences of gain and phase in the low frequency band (0.07-0.20 Hz) and the high frequency band (0.20-0.50 Hz) (all P>0.05). Conclusions:Transcranial Doppler combined with beat-to-beat pulse pressure can be used for the assessment of changes in immediate dynamic cerebral autoregulation after acute + Gz exposure, and transfer function analysis of ultra-low frequency band parameters is suitable for this type of evaluation.