Effects of Age and Sex on the Electromyographic Reaction Time of Tibialis Anterior Muscle Contraction

OBJECTIVE: Compared to elderly men, elderly women have substantially reduced performance of postural balance and greater risk of falls. To investigate the effect of age and sex on electromyographic (EMG) reaction time of tibialis anterior muscle contraction. METHOD: Fifty-nine elderly subjects and 29 young subjects participated in this study. Subjects were instructed to dorsiflex the ankle of the dominant leg as forcefully and quickly as possible in response to audible beeps. EMG activity was recorded over the tibialis anterior muscle and delays in initiation and termination of EMG signal were measured by two examiners. Mean and intrasubject variability of each delay were used as outcome measures. RESULTS: Both the intra-examiner and inter-examiner reliability of delay variables were above 0.97. Delays in initiation and termination of muscle contraction, as well as their intrasubject variability, were significantly greater in the elderly (p<0.01). However, there were no sex differences or interaction in all outcome measures. CONCLUSION: These results demonstrate that the EMG reaction time and their variability increase in the elderly population with no sex difference.

Matrix Synthesis of Human Intervertebral Disc Cells According to Grade of Degeneration: Under the Basal State and TGF-beta Stimulation / 대한척추외과학회지

STUDY DESIGN: In vitro experiment to determine the matrix synthesis of human intervertebral disc (IVD) cell according to grade of degeneration. OBJECTIVES: To quantify proteoglycan synthesis of human IVD cells in various grade of degeneration under the stimulation of TGF-beta. SUMMARY OF LITERATURE REVIEW: Sophisticated method to delivery of growth factors, in continuous manner, is the genetic modification of disc cells through gene transfer. Poor responsiveness of degenerated disc to anabolic stimuli can mitigate potential application of growth factor or therapeutic gene transfer in the management of degenerative disc disease. MATERIALS AND METHODS: IVD tissue was obtained from nineteen patients during surgical disc procedure. Grade of degeneration was confirmed by preoperative MRI. Isolation and three dimensional culture of disc cells were performed. Disc cells were treated with exogenous TGF-beta. Newly synthesized proteoglycans were assessed by 35 S-sulfate incorporation using chromatography on Sepadex G-25 in PD-10 columns. One-way analysis of variance with Fishers protected LSD posthoc test was performed to compare amount of newly synthesized proteoglycans and power analysis was also conducted. Significance level was set p<0.05. RESULTS: Difference between cultures of control (grade I) and degenerated (grade II-V) discs in proteoglycan synthesis in basal condition was statistically insignificant (p=0.35, power=0.21-0.63). Difference between cultures of control and degenerated disc in proteoglycan synthesis under the stimulated condition with TGF-beta was also statistically insignificant (p=0.54, power=0.24- 0.47). However cultures in stimulated condition showed increased amount of newly synthesized proteoglycans compared to those of basal condition regardless of the grade of degeneration (p<0.05). CONCLUSION: Anabolic response of human intervertebral disc cells is relatively insensitive to grade of disc degeneration, which facilitate application of gene therapy in various conditions of disc degeneration.

SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis) Syndrome occurred on the Clavicle: A Case Report / 대한정형외과학회잡지

Thirty years ago, osteoarticular disorders which are related to various skin lesions such as pustulosis, psoriasis and acne have been reported in Japan and northwestern Europe. This disease entity is composed of three major disorders, which include the hyperostosis of the anterior chest wall, chronic multifocal recurrent osteomyelitis involving the metaphysis of long bone and pustulotic arthro-osteitis. In 1987, Kahn and Chamot first coined the term SAPHO syndrome (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis) . Early lesions of the SAPHO syndrome contain acute inflammation, edema, and prominent periosteal bone formation, and which is indistinguishable from ordinary bacterial osteomyelitis. In addition, late lesions of that demonstrate bony sclerosis. Therefore, it is necessary to avoid misdiagnosis as Paget's disease and Ewing sarcoma. We experienced a case of SAPHO syndrome and report the clinical, radiological and pathological findings in detail.