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Biomedical subjects

John C Y Leong

Publications and source records attributed to John C Y Leong.

At least 19 recordsLinked to original sources
PubMed2006

Changes in melatonin receptors in relation to the development of scoliosis in pinealectomized chickens.

STUDY DESIGN: The 2[125I]iodomelatonin binding assay was used to investigate the involvement of melatonin receptors in the development of scoliosis in pinealectomized chickens. OBJECTIVE: To compare the binding properties of melatonin receptors in the thoracic spinal cord between pinealectomized chickens that had scoliosis develop and those that did not. SUMMARY OF BACKGROUND DATA: Surgical pinealectomy in young chickens induced scoliosis with a reported incidence of 50% to 100%. The factors regulating the development of scoliosis in this animal model are unclear. Melatonin receptors have been shown in the spinal cord of chickens, but their functions are still unknown. This study addresses the question as to whether spinal cord melatonin receptors are related to the pathogenesis of scoliosis in pinealectomized chickens. METHOD: Control and pinealectomized chickens were kept under controlled lighting conditions and monitored for scoliosis development. At 9-11 weeks after pinealectomy, thoracic spinal cords were removed for 2[125I]iodomelatonin binding assay, and blood was collected for serum melatonin assay at either the middle of the light period or middle of the dark period. RESULTS: Pinealectomy in young chickens produced: (1) loss of diurnal variations in serum melatonin levels, (2) 50% incidence of scoliosis, and (3) attenuation in the diurnal variations in the receptor affinity to melatonin. No differences were detected in the serum melatonin levels or binding of spinal cord melatonin receptors between the pinealectomized chickens that had scoliosis develop and those that did not. CONCLUSION: Changes are detected in melatonin receptor binding after pinealectomy. However, these changes cannot account for the reason why scoliosis develops in some chickens after pinealectomy, while it does not in others. Neither low melatonin serum level nor changes in spinal cord melatonin binding can be a sole etiologic factor in the pathogenesis of scoliosis in pinealectomized chickens.

Animals↗
PubMed2006

Association of the Taq I allele in vitamin D receptor with degenerative disc disease and disc bulge in a Chinese population.

STUDY DESIGN: Large scale, case-control study. OBJECTIVE: To assess the effect of the Taq I alleles in vitamin D receptor on the risk of developing degenerative disc disease in a Southern Chinese population. SUMMARY OF BACKGROUND DATA: Previous studies in Finns and Japanese suggest that the Taq I polymorphism of vitamin D receptor is associated with the development of degenerative disc disease in the lumbar spine. However, sample sizes were small, and the results need to be confirmed in other populations. METHOD: Lumbar degenerative disc disease was defined by magnetic resonance imaging (MRI) on 804 Southern Chinese volunteers between 18 and 55 years of age. Restriction enzyme digestion of polymerase chain reaction products was used to analyze the Taq I alleles. The resulting genotypes were correlated with the presence of lumbar disc degeneration and bulge on MRI. RESULTS: Using logistic regression analysis and adjusting for age and sex, the t allele of Taq I in vitamin D receptor gene was significantly associated with degenerative disc disease, with an odds ratio (OR) of 2.61 (95% confidence interval [CI] 1.15-5.90, P = 0.041). Further subgroup analysis showed that in individuals younger than 40 years, the OR was even higher, at 5.97 (95% CI 1.69-21.15, P = 0.002). Similarly, disc bulge was significantly associated with t allele (OR = 7.17, 95% CI 1.43-36.01, P = 0.001) in individuals younger than 40 years. Anular tears and the Schmorl nodes were not associated with the t allele of Taq I polymorphism. CONCLUSION: To our knowledge, this is the largest scale genetics study to date using MRI to define precisely degenerative disc disease in the Southern Chinese population. We showed that the t allele of vitamin D receptor Taq I is associated with a high risk of degenerative disc disease and disc bulge developing, especially in individuals younger than 40 years.

Adolescent↗
PubMed2006

Insulin-like growth factor-1 treatment prevents anti-Fas antibody-induced apoptosis in endplate chondrocytes.

STUDY DESIGN: In vitro investigation of vertebral endplate chondrocyte apoptosis. OBJECTIVES: To determine whether Fas antibody caused apoptosis in endplate chondrocytes, and whether insulin-like growth factor-1 (IGF-1) inhibited this effect. Integrin-alpha1 and focal adhesion kinase (FAK) expression in conjunction with apoptosis was also investigated. SUMMARY OF BACKGROUND DATA: Binding of Fas antibody to Fas mimics Fas-FasL ligation, which causes apoptosis. IGF-1 has been shown to have anti-apoptotic effects. MATERIALS AND METHODS: Rat cervical endplate chondrocytes were cultured and treated with Fas antibody, with or without IGF-1. Cellular morphology was examined by microscopy. Apoptotic changes were evaluated by transmission electron microscopy, TUNEL staining, and immunostaining. Apoptosis-induced changes in the expression of integrin-alpha1 chain and FAK were also investigated. RESULTS: Endplate chondrocytes were able to be cultured; a chondrocytic phenotype was maintained. Fas antibody induced apoptosis in endplate chondrocytes; this was confirmed by TUNEL staining. Bcl-2 expression was decreased by Fas antibody, while Bax expression increased. Integrin-alpha1 and FAK expression was decreased by Fas antibody. IGF-1 treatment inhibited these Fas antibody-induced changes. CONCLUSIONS: Fas antibody induces apoptosis and decreases Integrin-alpha1 and FAK expression in cultured endplate chondrocytes; IGF-1 is protective against these changes.

Animals↗
PubMed2006

Continuous dynamic spinal motion analysis.

STUDY DESIGN: Continuous dynamic lumbar intervertebral flexion-extension is assessed by a videofluoroscopy with a new auto-tracking system. OBJECTIVES: To develop and validate a new method for the continuous assessment of lumbar kinematics. SUMMARY OF BACKGROUND DATA: Instability of the lumbar spine is thought to be associated with low back pain, but the diagnosis remains difficult. Functional radiographs have been used for diagnosis of spinal instability but error and limitation exist, whereas videofluoroscopy provides a cost-effective way for such analysis. However, common approaches of image analysis of videofluoroscopic video are tedious and time-consuming because of the low quality of the images. Physicians have to extract the vertebrae manually in most cases; thus, continuous motion analysis is hardly achieved. METHODS: A new system that can perform automatic vertebrae segmentation and tracking is developed. In vitro and in vivo validity were evaluated. Intervertebral flexion and extension was assessed in 30 healthy volunteers. RESULTS: In vitro and in vivo validity tests have been conducted with good results. A linear-liked pattern of the intervertebral flexion-extension (IVFE) curves in different levels was found, and the IVFE decreased in descending order from L1-L5 at different points of range of motion in flexion. Conversely, extension is evenly contributed at different levels, and the concavity of lumbar lordosis increases steadily in backward movement. CONCLUSIONS: The newly developed technique in assessing the dynamic lumbar motion is reliable and able to analyze the lumbar intervertebral movement from videofluoroscopic images automatically and accurately. The proposed system requires less human intervention than common approaches. It may have a potential value in the evaluation of spinal "instability" in clinical practice.

Adult↗
PubMed2005

The TRP2 allele of COL9A2 is an age-dependent risk factor for the development and severity of intervertebral disc degeneration.

STUDY DESIGN: Low back pain (LBP) and sciatica are usually caused by degenerative disc disease (DDD). Although they are common, the etiology of these conditions is poorly understood. A large population case-control study in the Southern Chinese was performed to study genetic risk factors to DDD. OBJECTIVES: To gain a better understanding of the etiology of DDD in relation to structural defects of the intervertebral disc. SUMMARY OF BACKGROUND DATA: A Finnish study found an association between LBP and sciatica with two variants of the alpha-chains of collagen IX, encoded by the Trp2 and Trp3 alleles, representing Gln326Trp and Arg103Trp amino acid substitutions in the COL9A2 and COL9A3 genes, respectively. Trp2 was found only in affected individuals (4%), whereas Trp3 was present in both affected (24%) and unaffected (9%) individuals. Because of the low frequency of the Trp2 allele in whites, the significance and contribution of this allele to DDD are not known. Using more objective criteria to define the disease by magnetic resonance imaging (MRI), we tested these alleles for association with DDD in a large population study. METHODS: Lumbar DDD, the presence of anular tears, and disc and endplate herniations were defined by MRI in 804 Southern Chinese volunteers 18 to 55 years of age. These were correlated with the frequencies of the Trp2 and Trp3 alleles. RESULTS: The Trp2 allele was present in 20% of the population and was associated with a fourfold increase in the risk of developing anular tears at 30 to 39 years and a 2.4-fold increase in the risk of developing DDD and endplate herniations at 40 to 49 years. Affected Trp2 individuals had more severe degeneration. The Trp3 allele was absent from the Southern Chinese population. CONCLUSION: This largest-ever population study using MRI to define DDD demonstrates for the first time that the Trp2 allele is a significant risk factor for the development and severity of degeneration. The association is age- dependent as it is more prevalent in some age groups than in others. The contrasting Trp allele frequencies between the Finns and the Chinese are the first indication that the genetic risk factors for DDD varies between ethnic groups.

Adolescent↗
PubMed2005

The effect of pinealectomy on scoliosis development in young nonhuman primates.

STUDY DESIGN: Prospective study on pinealectomy in primates. OBJECTIVE: To evaluate whether pinealectomy in a bipedal nonhuman primate model will result in the development of scoliosis. SUMMARY OF BACKGROUND DATA: Pinealectomy in newborn chickens consistently resulted in scoliosis development. Published data suggest that the surgical removal of the pineal, loss of melatonin secretion, and a bipedal posture are important elements in the development of scoliosis in lower animal models. METHOD: There were 18 rhesus monkeys between 8 and 11 months old that underwent pineal excision. All monkeys were kept in a regulated 12-hour light-dark cycle. Monthly radiographs assessed scoliosis development. Completeness of pineal excision was assessed by measurement of a major metabolite of melatonin in the urine, 6-sulfatoxymelatonin, using an enzyme-linked immunosorbent assay assessed. RESULTS: Mean follow-up was 28 months (range 10-41). Seven monkeys died prematurely, and 11 survived to date; the data from those that died could still be used, although follow-up was shortened. At the latest follow-up or death, scoliosis did not develop in any of the monkeys. Urinary 6-sulfatoxymelatonin measurements revealed 3 patterns. Group 1 consisted of 10 monkeys, which showed definite evidence of complete pineal excision. Group 2 consisted of an uncertain group of 2 monkeys in which the nighttime melatonin level is slightly high. Group 3 consisted of 6 monkeys that had incomplete pineal excision or ectopic melatonin production. CONCLUSIONS: To our knowledge, this is the first report of pinealectomy in nonhuman primates. Of the 18 monkeys, 10 had a loss of melatonin secretion, for a mean of 29 months after surgery. Because none of the monkeys had scoliosis develop, this study strongly suggests that the possible etiologic factors producing idiopathic scoliosis in lower animals are different from primates, and findings in lower animals cannot necessarily be extrapolated to human beings.

Animals↗
PubMed2005

Vertebroplasty by use of a strontium-containing bioactive bone cement.

STUDY DESIGN: A review of the laboratory and clinical data for a new strontium-containing hydroxyapatite bioactive bone cement. OBJECTIVES: To compare the properties of the strontium-containing bioactive bone cement with those of polymethyl methacrylate (PMMA) and hydroxyapatite (HA) bone cements. SUMMARY OF BACKGROUND DATA: Vertebroplasty and kyphoplasty using conventional PMMA bone cements have been effectively used to treat osteoporotic spine fractures with good short- and medium-term results. However, PMMA has some undesirable properties, including its high setting temperature, lack of osseointegration, and large stiffness mismatch with osteoporotic bone. These properties are responsible for some postoperative complications. METHODS: Strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement consists of a filler blend of strontium-containing hydroxyapatite, fumed silica and benzoyl peroxide; and a resin blend of bisphenol A diglycidylether methacrylate, triethylene glycol dimethacrylate, poly(ethylene glycol) methacrylate, and N, N-dimethyl-p-toluidine. Its properties, including mechanical strength, setting temperature, biocompatibility, and osseoinduction, were compared with other cements in vitro and in vivo. Early clinical results are presented. RESULTS: The Sr-HA cement has a setting time of 15 to 18 minutes, a maximum setting temperature of 58 degrees C, a compressive strength of 40.9 MPa, bending strength of 31.3 MPa, and a bending modulus of 1,408 MPa. The bending strength and modulus are closer to human cancellous bone. Sr-HA cement promotes osteoblast attachment and mineralization in vitro and bone growth and osseointegration in vivo. In a pilot study, 23 cases of osteoporotic fractures treated with this cement with a mean follow-up of 18 months suggest that it is as effective as PMMA in relieving pain. DISCUSSIONS: Oral strontium has been shown to induce new bone formation and is effective in reducing fracture risk in osteoporosis. Our data suggest that strontium delivered locally has the same effect; thus, the combination of strontium with HA in a cement with a low setting temperature, adequate stiffness, and low viscosity makes this a good bioactive cement for vertebroplasty and kyphoplasty.

Animals↗
PubMed2005

Pure shear properties of lumbar spinal joints and the effect of tissue sectioning on load sharing.

STUDY DESIGN: An in vitro biomechanical study on lumbar intervertebral joints. OBJECTIVES: To examine the mechanical properties of lumbar motion segments under pure shear loading and establish whether a simple model for functional differentiation between the anterior column and the posterior elements is applicable. SUMMARY OF BACKGROUND DATA: Anteroposterior shear has been implicated as a major factor in spinal instability. There is a substantial amount of data on shear motion as a coupled part of flexion-extension; data on the pure shear properties of intervertebral joints is limited. METHODS: Eighteen human cadaver lumbar motion segments were subject to nondestructive testing under pure shear loads (anterior shear and posterior shear). An MTS standard testing machine was used to record the load-deformation characteristics of specimens subject to deformation at a constant rate to a maximum shear load of approximately 250 N. Tissue sectioning was then performed with the specimen mounted in the testing machine. Eight specimens were sectioned through the intervertebral disc, including the anterior and posterior longitudinal ligaments, and 8 specimens were sectioned through the pedicles to remove the posterior elements. The same deformation pattern applied to the intact specimen was then reapplied to the sectioned specimen, and the load-deformation characteristics following sectioning were evaluated. RESULTS: The shear stiffness of the intact segments were found to be higher in anterior shear (mean group A = 583.8, B = 607 N/mm) than in posterior shear (mean group A = 469, B = 438.4 N/mm). Section of the anterior column and adjacent longitudinal ligaments resulted in a mean stiffness decreased by 22.8% of the intact value under anterior shear and 23.9% under posterior shear. Much larger change in shear stiffness was seen, and the mean sectioned stiffness dropped by 77.7% in anterior shear and 79% in posterior shear after removal of the posterior elements. After the anterior column was sectioned, 12% and 18% increases in the deformation for anterior and posterior directions were seen, whereas a distinct increase in the deformations was found after posterior elements sectioned. CONCLUSIONS: The posterior elements of the lumbar spine are more efficient in resisting anterior and posterior shear loads. However, the anterior column will exhibit similar load-displacement characteristics if subject to greater deformations. The sum of the normalized mean shear loads of the anterior column and posterior elements sustained at maximum intact deformation is significantly different from the shear load sustained by the intact spine at the same deformation. A simple concept of load sharing between the anterior column and the posterior elements may not be valid.

Adult↗
PubMed2004

The flexion-extension profile of lumbar spine in 100 healthy volunteers.

STUDY DESIGN: Dynamic lumbar flexion-extension motions were assessed by an electrogoniometer and a videofluoroscopy unit simultaneously. OBJECTIVES: The aims of this study were to assess the motion profile of lumbar spine in different genders and age groups and to assess their differences. SUMMARY OF BACKGROUNDS DATA: The dynamic lumbar flexion-extension motions analysis method has been developed and validated. However, data profile of the spinal motions of healthy volunteers has not been established. METHODS.: A total of 100 healthy volunteers, including 50 men and 50 women, were recruited. They were then divided into four equal groups, following their age ranges of 21 to 30 years, 31 to 40 years, 41 to 50 years, and 51 years and older. Lumbar flexion-extension motion was assessed with an electrogoniometer and videofluoroscopy simultaneously. Radiologic images of the lumbar spine were captured during flexion-extension in 10 degrees intervals. Intervertebral flexion-extension (IVFE) of each vertebral level was calculated. The spinal motion of different genders was compared segment by segment with independent t test. The spinal motion of different age groups was compared with one-way analysis of variance. RESULTS: A linear-liked pattern of the IVFE curves was observed in different genders and age groups. No statistically significant difference in the pattern of motion was found between genders. However, statistically significant difference in the slope of IVFE curves was found at all lumbar levels in subjects whose age was 51 years or older (P < 0.05). CONCLUSIONS: Assessment of motion profile was found to be helpful for the identification of spinal disorders in clinical practice. Because of the normal variation of spinal motion of subjects in different age ranges, interpretation of spinal motion disorders should be careful. Although the sample size in this study was limited, the database generated might be useful to assist the diagnosis of spinal "instability" in the future.

Adult↗
PubMed2003

Primary thoracolumbar scoliosis in pinealectomized chickens.

STUDY DESIGN: This study examines the gross anatomic changes in the chicken spine after pinealectomy and was undertaken because initial observation suggested that the pattern of curve development appears to be different from that reported in the literature. OBJECTIVE: To characterize the spinal deformity in chickens after pinealectomy. SUMMARY OF BACKGROUND DATA: The most common curve pattern seen after pinealectomy in chickens is said to be thoracic curves with structural changes and rotation. This is based largely on radiographic observations and forms the basis of the claim that chicken and human adolescent idiopathic scoliosis are similar. METHOD: Thirty-five chickens were divided into 2 groups, a pinealectomy group (n = 25) and a control group with no surgery performed (n = 10). The spines were harvested at 3 months of age and examined visually, by radiographs and computed tomography scans. RESULTS: Thirteen out of 25 (52%) of the pinealectomized chickens developed scoliosis. In contrast to previous studies, all the curves were located at the thoracolumbar junction with the apex at either T7 or L1. Structural changes including apical vertebral wedging, lordosis (mean of 14.3 degrees ), and rotation (mean of 14 degrees ) were seen in all cases. Pelvic wing deformity was seen in all cases and significantly contributed to the posterior rotational hump. CONCLUSION: The primary curve in these chickens is at the thoracolumbar junction. Previous reports of curve pattern based on radiographic findings would not have identified these as the thoracolumbar junction is obscured by the bony pelvis and heavy musculature. The finding of pelvic wing deformity has not been previously reported, and raises the question as to whether these curves are secondary to asymmetric muscle pull.

Animals↗
PubMed2003

Effect of melatonin suppression on scoliosis development in chickens by either constant light or surgical pinealectomy.

STUDY DESIGN: This study was designed to compare the effect of suppression of melatonin secretion by bright light in chickens with that of surgical pinealectomy. OBJECTIVE: To determine whether suppression of melatonin secretion without surgery in chickens can result in scoliosis development. SUMMARY OF BACKGROUND DATA: Pinealectomy in chickens consistently produces scoliosis with anatomic characteristics similar to those of human idiopathic scoliosis. Conversely, cutting of the pineal stalk without removal of the pineal gland will also result in scoliosis. This study addresses the question of whether constant bright light can induce scoliosis formation, because it is well known that 24-hour bright lighting conditions can suppress the secretion of melatonin to an equivalent level as pinealectomy. MATERIALS AND METHOD: Seventy-seven newborn Nihon chickens were separated into three groups. A control group (n = 21) with no surgery performed; a pinealectomy group (n = 15) that served as surgical controls; and a constant light group (n = 41). The first two groups were kept together in a strict 12-hour light-dark cycle, whereas the third group was separately kept with constant lighting conditions (>100 lux). All the chickens were radiographed at two weekly intervals, and blood was taken during the middle of the light and dark cycles for serum melatonin assay using ELISA. RESULTS: Fifty-four percent of the pinealectomized chickens had scoliosis develop by 6 weeks. None of the constant-light chickens or controls had scoliosis develop for up to 11 weeks. Measurements of serum melatonin levels of the constant light group confirm that secretion is suppressed. CONCLUSION: This study suggests that for scoliosis to develop in chickens, the surgical operation itself is important and challenges the role of melatonin as an isolated etiological factor in the development of scoliosis.

Animals↗
PubMed2003

Adeno-associated virus-mediated bone morphogenetic protein-4 gene therapy for in vivo bone formation.

Adeno-associated virus (AAV) is so far the most valuable vehicle for gene therapy because it has no association with immune response and human disease. The present study was conducted to investigate the feasibility of AAV-mediated BMP4 gene transfer for bone formation. In vitro study suggested that AAV-BMP4 vectors could transduce myoblast C2C12 cells and produce osteogenic BMP4. In vivo study demonstrated that new bone formation could be induced by direct injection of AAV-BMP4 into the skeletal muscle of immunocompetent rats. Histological analysis revealed that the newly formed bone was induced through endochondral mechanism. Immunohistochemical staining further demonstrated that AAV-BMP4 gene delivery could mediate long-term transduction, and the involvement of BMP4 expression was responsible for the endochondral ossification. This study is, to our knowledge, the first report in the field of AAV-based BMP gene transfer and should be promising for clinical orthopaedic applications.

Animals↗
PubMed2003

Reduction of disc space distraction after anterior lumbar interbody fusion with autologous iliac crest graft.

STUDY DESIGN: A retrospective review with long-term clinical and radiologic assessment was conducted. OBJECTIVE: To assess the severity and reasons for the reduction of disc space distraction after successful autograft fusion of the lumbar spine and its clinical consequences. SUMMARY OF BACKGROUND DATA: Anterior lumbar interbody fusion is an established treatment for lumbar disc degeneration. It is not firmly established whether the grafted level narrows after surgery, and if so, what the clinical consequences are. METHODS: This study assessed 67 patients who underwent anterior lumbar interbody fusion at L4-L5 with autologous iliac crest graft. The disc space height and angle between L4 and L5 were serially measured. Times until fusion and the presence of symptoms before and after surgery and at the latest follow-up assessment were noted. RESULTS: The mean follow-up period was 14 years (range, 2.5-32 years). The fusion rate was 96% (64 of 67 patients), and the mean time to fusion was 9 months. In the group that had successful fusion, there was an initial increase in disc space distraction followed by a reduction in 55 patients (86%). The mean preoperative disc space height was 12.1 mm, which increased immediately after surgery to 16.2 mm, but had been reduced to 12.6 mm at the latest follow-up assessment. The reduction in distraction occurred within the first 3 months after surgery and was correlated with age, but not with recurrence of symptoms, the amount of initial distraction, or the gender of the individual. A similar trend was seen with L4-L5 segmental angulation. CONCLUSIONS: Reduction of disc space distraction after anterior lumbar interbody fusion using tricortical iliac crest bone graft is a common finding. Despite this, the fusion rate is high, and there is no association with symptom recurrence.

Adolescent↗
PubMed2003

Reconstruction of forearm deformities in multiple cartilaginous exostoses.

The management of complex forearm deformities in patients with multiple cartilaginous exostoses is controversial. The objective of this study is to look into the outcome of treatment with the combined use of ulna lengthening, radial osteotomy, and excision of exostosis in our six patients, who all had Masada type 1 deformity of the forearm. Clinical assessment was performed using the pre- and postoperative range of motion of the wrist, forearm and elbow. The chief symptom each patient had was noted as well as the demographic data of all patients. Radiological assessment was performed by checking the degree of negative ulna variance, the radial articular angle, and the degree of carpal slip. The degree of satisfaction of the patients and their parents were noted. Good clinical and radiological results were obtained at a mean follow-up of 2.5 years. All patients and parents were satisfied and there was no recurrence of deformity in the latest follow-up. The authors believe in early and aggressive treatment of Masada type 1 deformity of the wrist and forearm for multiple cartilaginous exostoses with a combination of excision of exostosis, ulna lengthening and radial osteotomy.

Bone Lengthening↗
PubMed2002

In vivo new bone formation by direct transfer of adenoviral-mediated bone morphogenetic protein-4 gene.

Previous studies have demonstrated that bone morphogenetic protein-4 (BMP4) could participate in vivo endochondral ossification and is one of the main local contributing factors in the early stage of fracture healing. To investigate the effectiveness of BMP4 gene transfer, we constructed an adenoviral vector, Ad-BMP4, and evaluated its osteoinduction activity both in vitro and in vivo. In vitro study suggested that this vector could efficiently transduce mouse myoblast C2C12 cells and produce osteogenic BMP4 protein, as confirmed by immunofluorescence analysis and alkaline phosphatase activity assay. For in vivo study, Ad-BMP4 was directly injected into the hind limb muscles of male athymic nude rats. Visible new bone formation under X-ray films could be detected as early as three weeks post-injection. The bone tissue was further analyzed by histological staining and revealed a typical remodeled bone structure. In conclusion, this study is the first to establish the feasibility of adenovirus-based BMP4 gene therapy for bone regeneration.

Adenoviridae↗
PubMed2002

Paraspinal muscle activities of patients with scoliosis after spine fusion: an electromyographic study.

STUDY DESIGN: This prospective study compared the electromyographic activities of paraspinal muscles between normal subjects and patients with scoliosis before and after spine fusion. OBJECTIVE: To investigate the functional changes of paraspinal muscles before and after spine fusion using surface electromyography. SUMMARY OF BACKGROUND DATA: Idiopathic scoliosis is a common spine deformity. Surgical correction followed by spine fusion is the basic method of treatment, but the functional changes in paraspinal muscles after spine fusion still are unknown. METHODS: For this study, 15 healthy subjects and 19 patients with idiopathic scoliosis were recruited. All 19 patients received posterior spine fusion from T2 to T5 to T12. The surface electromyography for normal subjects and for patients before and after spine fusion was recorded bilaterally along the thoracic and lumbar paraspinal muscles for different postures. Root mean square and median frequency values of electromyographic activities were used to compare results between normal subjects and patients with scoliosis before and after spine fusion. RESULTS: Electromyographic activities showed significant differences between normal control subjects and patients with pre- or postoperative scoliosis. After spine fusion, electromyography showed lower root mean square activity in the thoracic region and higher root mean square activity in the lumbar region. Patients with preoperative scoliosis showed lower median frequency in the thoracic region and higher median frequency in the lumbar region than normal subjects and patients with postoperative scoliosis. The group with preoperative scoliosis showed the least symmetrical paraspinal muscle activity, followed by the postoperative and normal groups. CONCLUSIONS: Patients with scoliosis present unbalanced electromyographic activity in the paravertebral muscles, which is diminished by spine fusion, but does not return to the values found in normal subjects. The paraspinal muscles in the thoracic region showed lower activity after spine fusion, probably because of atrophy. Higher muscular activity was found in the lumbar region, which may lead to muscle hypertrophy.

Adolescent↗