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Objective To investigate the effects of gastrocnemius muscle forces on biomechanical mechanism of heel pain. Methods The finite element model of the foot including foot bone, soft tissues, ligaments and plantar fascia was reconstructed based foot CT images by Mimics software. The gastrocnemius force applied on the foot was 40%-90% of half-body weight（320 N） with increment of 5% of half-body weight（16 N）. The plantar surface pressure distribution and peak pressure as well as the plantar fascia stress were calculated. Results The plantar surface pressure distribution was mainly concentrated on the heel and metatarsal head. With the increase of gastrocnemius force, the peak plantar pressure at the heel decreased, while the peak pressure at the front of the foot decreased at first and then increased, which reached the minimum value with the load of 224 N. The plantar fascia stress increased with the gastrocnemius force increasing. Conclusions Gastrocnemius force applied on the foot has a significant influence on the plantar pressure distribution. Finite element analysis can contribute to understanding etiology and pathology of foot diseases, predicting the biomechanical results of the treatment and provide theoretical reference for treatments.
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Objective To investigate the effects from various angles between inferior vein cava (IVC) and right hepatic vein (RHV) on pathogenesis of IVC membranous obstruction for patients with Budd-Chiari syndrome (BCS). Methods The normal 3D solid model of IVC and hepatic veins was reconstructed using MRI angiograms, and the angle between IVC and RHV was 56°. The two models with IVC-RHV angle of 30° and 120° were established, respectively, based on the reconstructed model. The distributions of wall shear stress, static pressure and blood velocity of the 3 models were calculated by numerical simulation. Results The wall shear stresses, static pressure and blood velocity of the 3 models displayed significantly differences. Compared with the normal 56° model, the 30° model showed a higher wall pressure and lower blood velocity, while the 120° model presented a lower wall pressure and blood velocity with turbulence of blood flowing, and such hemodynamic changes would increase the risk of thrombosis. The 56° model had the fastest blood velocity. Conclusions Numerical simulation of the flow in IVC and RHV can promote to discover the pathogenesis of BCS, and help to predict risk of IVC membranous obstruction, and provide theoretical references for BCS treatment.
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<p><b>OBJECTIVE</b>To investigate the relationship of susceptibility loci in chromosomes 1q21-25 and 6p21-25 and schizophrenia subtypes in Chinese population.</p><p><b>METHODS</b>A genomic scan and parametric and non-parametric analyses were performed on 242 individuals from 36 schizophrenia pedigrees, including 19 paranoid schizophrenia and 17 undifferentiated schizophrenia pedigrees, from Henan province of China using 5 microsatellite markers in the chromosome region 1q21-25 and 8 microsatellite markers in the chromosome region 6p21-25, which were the candidates of previous studies. All affected subjects were diagnosed and typed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revised (DSM-IV-TR; American Psychiatric Association, 2000). All subjects signed informed consent.</p><p><b>RESULTS</b>In chromosome 1, parametric analysis under the dominant inheritance mode of all 36 pedigrees showed that the maximum multi-point heterogeneity Log of odds score method (HLOD) score was 1.33 (α = 0.38). The non-parametric analysis and the single point and multi-point nonparametric linkage (NPL) scores suggested linkage at D1S484, D1S2878, and D1S196. In the 19 paranoid schizophrenias pedigrees, linkage was not observed for any of the 5 markers. In the 17 undifferentiated schizophrenia pedigrees, the multi-point NPL score was 1.60 (P= 0.0367) at D1S484. The single point NPL score was 1.95(P= 0.0145) and the multi-point NPL score was 2.39 (P= 0.0041) at D1S2878. Additionally, the multi-point NPL score was 1.74 (P= 0.0255) at D1S196. These same three loci showed suggestive linkage during the integrative analysis of all 36 pedigrees. In chromosome 6, parametric linkage analysis under the dominant and recessive inheritance and the non-parametric linkage analysis of all 36 pedigrees and the 17 undifferentiated schizophrenia pedigrees, linkage was not observed for any of the 8 markers. In the 19 paranoid schizophrenias pedigrees, parametric analysis showed that under recessive inheritance mode the maximum single-point HLOD score was 1.26 (α = 0.40) and the multi-point HLOD was 1.12 (α = 0.38) at D6S289 in the chromosome 6p23. In nonparametric analysis, the single-point NPL score was 1.52 (P= 0.0402) and the multi-point NPL score was 1.92 (P= 0.0206) at D6S289.</p><p><b>CONCLUSION</b>Susceptibility genes correlated with undifferentiated schizophrenia pedigrees from D1S484, D1S2878, D1S196 loci, and those correlated with paranoid schizophrenia pedigrees from D6S289 locus are likely present in chromosome regions 1q23.3 and 1q24.2, and chromosome region 6p23, respectively.</p>
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Adult , Humans , Middle Aged , Young Adult , Chromosomes, Human , Genetic Linkage , Genetic Loci , Genetic Predisposition to Disease , Microsatellite Repeats , Genetics , Schizophrenia , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of nano-hydroxyapatite/collagen (nHA/collagen) composite as a graft extender and enhancer when combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) on lumbar intertransverse fusion in rabbits.</p><p><b>METHODS</b>Sixty-four adult female New Zealand white rabbits, aged 1 year and weighing 3.5-4.5 kg, underwent similar posterolateral intertransverse process arthrodesis and were randomly divided into 4 groups based on different grafts: autogenous cancellous bone alone (ACB group), nHA/collagen alone (HAC group), half autogenous cancellous bone and half nHA/collagen (ACB+HAC group) and nHA/collagen combined with rhBMP-2 (HAC+BMP group). The fusion masses were analyzed by manual palpation, radiography, biomechanical testing and histological examination.</p><p><b>RESULTS</b>Fusion was observed in 4 cases in the 6th week and in 5 cases in the 10th week after surgery in ACB group. No case showed fusion in HAC group. In ACB+HAC group, there was fusion in 3 cases in the 6th week and in 4 cases in the 10th week after surgery. In HAC+BMP group, fusion in 1 case was found in the 4th week, in 5 cases in the 6th week and in 6 cases in the 10th week after surgery. It suggested that ACB, ACB+HAC and HAC+BMP groups showed similar fusion ratio and mechanical strength in the 6th and 10th week after surgery. According to the microstructure analysis of the samples, nHA/collagen had no negative effect when implanted together with ilium autograft. In HAC+BMP group, new bone-like tissue was observed in the 2nd week postoperatively, and nearly all of the implanted composites were replaced by mature bone matrix and new bones in 10th week postoperatively.</p><p><b>CONCLUSIONS</b>The nHA/collagen, especially combined with rhBMP-2, is a promising bone substitute, for it has quick biodegradation, fine bone-bending ability, and high osteoconductivity on posterolateral spinal fusion in rabbits.</p>