Computational evaluation of wire position using separate vertical wire technique and candy box technique for the fixation of inferior pole patellar fractures: a finite element analysis.

The separate vertical wire (SVW) technique and the improved candy box (CB) technique have been proposed for treating inferior pole patellar fractures. However, there is still a lack of clear explanation regarding the location of the wire passing through the patella. Five models of SVW techniques were established in different positions. Finite element analysis was then conducted to determine the optimal bone tunnel position for the SVW technique. Based on these findings, six groups of finite element models were created for CB techniques. The maximum displacement and stress on both the patella and steel wire were compared among these groups under 100-N, 200-N, 300-N, 400-N, and 500-N force loads. The results indicated that, in the SVW technique, the steel wire group near the fracture end of the longitudinal bone tunnel showed minimal displacement and stress on the patella when subjected to different forces. On the other hand, in the CB technique, both the patella and wire experienced minimal stress when a transverse bone tunnel wire was placed near the upper posterior aspect of patella. In conclusion, the SVW technique may require the bone tunnel wire to be positioned near the fractured end of the lower pole of the patella. On the other hand, in CB technique, the transverse bone tunnel wire passing through the patella may be close to its upper posterior aspect. However, further validation is necessary through comprehensive finite element analysis and additional biomechanical experiments.

The polymorphism of CLOCK gene 3111T/C C>T is associated with susceptibility of Alzheimer disease in Chinese population.

OBJECTIVES: In the present study, it was examined whether polymorphism of circadian locomotor output cycle kaput (CLOCK) gene 3111T/C was associated with susceptibility of Alzheimer disease (AD). METHODS: This study was conducted using a case-control method. Genotypes of apolipoprotein E (APOE e4) and CLOCK gene 3111T/C were determined by restriction fragment length polymorphism method and TaqMan assay method, respectively. RESULTS: In this study, we gathered 296 unrelated AD patients and 423 control subjects. Both in the whole sample and APOE e4 noncarriers, prevalence of C carriers in CLOCK gene 3111T/C in AD patients was significantly higher than that in control subjects (in the whole sample: χ = 37.615, P < 0.0001; in APOE e4 noncarriers: χ = 46.809, P < 0.0001). However, among APOE e4 carriers, prevalence of C carriers in CLOCK gene 3111T/C between patients and control subjects presents nonsignificant difference (χ = 0.812, P = 0.451). CONCLUSIONS: Among APOE e4 noncarriers, C carriers in CLOCK gene 3111T/C were associated with a high susceptibility of AD, but among APOE e4 carriers, the functional polymorphism of CLOCK gene 3111T/C was not associated with the susceptibility of AD.

Genetic engineering neural stem cell modified by lentivirus for repair of spinal cord injury in rats.

OBJECTIVE: To explore the feasibility for therapy of spinal cord injury (SCI) by genetic engineering neural stem cell (NSC) modified by lentiviral vector. METHODS: Following the construction of the genetic engineering NSC modified by lentivirus to secrete both neurotrophic factor-3 (NT-3) and green fluorescence protein (GFP), hemisection of spinal cord at the level of T10 was performed in 56 adult Wistar rats that were randomly divided into 4 groups (n = 14), namely 3 therapeutic groups and 1 control group. The therapeutic groups were dealed with NSC, genetic engineering NSC, and concentrated lentiviral supernatant which carries both GFP and NT-3, respectively. Then used fluorescence microscope to detect the transgenic expression in vitro and in vivo, migration of the grafted cells in vivo, and used the Basso, Beattie, and Bresnahan (BBB) open-field locomotor test to assess the recovery of function. RESULTS: The transplanted cells could survive for long time in vivo and migrate for long distance. The stable transgenic expression could be detected in vivo. The hindlimb function of the injured rats in 3 therapeutic groups, especially those dealed with genetic engineering NSC, improved obviously. CONCLUSION: It is feasible to combine NSC with lentivirus for the repair of SCI. NSC modified by lentivirus to deliver NT-3, acting as a source of neurotrophic factors and function cell in vivo, has the potential to participate in spinal cord repair.

The experimental study of genetic engineering human neural stem cells mediated by lentivirus to express multigene.

OBJECTIVE: To explore the feasibility to construct genetic engineering human neural stem cells (hNSCs) mediated by lentivirus to express multigene in order to provide a graft source for further studies of spinal cord injury (SCI). METHODS: Human neural stem cells from the brain cortex of human abortus were isolated and cultured, then gene was modified by lentivirus to express both green fluorescence protein (GFP) and rat neurotrophin-3 (NT-3); the transgenic expression was detected by the methods of fluorescence microscope, dorsal root ganglion of fetal rats and slot blot. RESULTS: Genetic engineering hNSCs were successfully constructed. All of the genetic engineering hNSCs which expressed bright green fluorescence were observed under the fluorescence microscope. The conditioned medium of transgenic hNSCs could induce neurite flourishing outgrowth from dorsal root ganglion (DRG). The genetic engineering hNSCs expressed high level NT-3 which could be detected by using slot blot. CONCLUSIONS: Genetic engineering hNSCs mediated by lentivirus can be constructed to express multigene successfully.