Research status on finite element analysis of bone drilling / 上海交通大学学报（医学版）

In recent years, the virtual surgery training system with force feedback has provided a new way for young doctors to improve their surgical skills in a safe, efficient and flexible training method. Precise drilling force and realistic hand feeling of manipulation are the cruxes in the virtual surgery training, and the accurate simulation of bone drilling depends on the accurate establishment of drilling force prediction model. The establishment of force prediction model with finite element analysis is the key part in the development of virtual training system. In this paper, the current research status of finite element analysis of bone drilling presented in four aspects: bone model reconstruction, material model, mesh model and prediction of drilling force, especially the construction of bone tissue material model is discussed in detail and several important models are analyzed. This paper presented a relatively complete overview of the approaches commonly used in this research field to promote the establishment of more accurate force prediction models of bone drilling.

Research status on finite element analysis of bone drilling / 上海交通大学学报（医学版）

In recent years,the virtual surgery training system with force feedback has provided a new way for young doctors to improve their surgical skills in a safe,efficient and flexible training method.Precise drilling force and realistic hand feeling of manipulation are the cruxes in the virtual surgery training,and the accurate simulation of bone drilling depends on the accurate establishment of drilling force prediction model.The establishment of force prediction model with finite element analysis is the key part in the development of virtual training system.In this paper,the current research status of finite element analysis of bone drilling presented in four aspects:bone model reconstruction,material model,mesh model and prediction of drilling force,especially the construction of bone tissue material model is discussed in detail and several important models are analyzed.This paper presented a relatively complete overview of the approaches commonly used in this research field to promote the establishment of more accurate force prediction models of bone drilling.

Effect of diallyl disulfide on learning and memory abilities and hippocampal synapses in mouse models of Alzheimer's disease / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the effect of diallyl disulfide (DADS) on hippocampal synapses and learning and memory abilities in a mouse model of A1zheimer's disease (AD).</p><p><b>METHODS</b>Mouse models of AD established by agglutinated Aβ1-42 injection in the lateral cerebral ventricle were randomized into 4 groups and treated with DADS at the daily doses of 0, 10, 50 and 100 mg/kg by gavage for 30 consecutive days. The learning and memory abilities of the mice were assessed with Morris water maze test; the structures of the dendritic spines and synapses in CA1 region of the hippocampus were observed under transmission electron microscope with silver staining; PSD95 and SYP protein and mRNA expressions in the hippocampus were detected with Western blotting and RT-PCR.</p><p><b>RESULTS</b>Compared with the AD model mice, the mice treated with 50 and 100 mg/kg DADS showed enhanced learning and memory abilities in Morris water maze test. The dendritic spines and synapses in CA1 region of the hippocampus increased obviously and hippocampal expressions of PSD95 and SYP were enhanced in mice treated with 50 and 100 mg/kg DADS.</p><p><b>CONCLUSION</b>DADS at the daily doses of 50 and 100 mg/kg can improve the learning and memory abilities and increase the number of dendritic spines and synapses in the hippocampus in mouse models of AD.</p>

Extracellular Ca(2+)-sensing receptor-induced extracellular Ca2+ influx is down-regulated by caveolin-1 in human umbilical vein endothelial cells / 生理学报

Although the function of extracellular Ca(2+)-sensing receptor (CaR) is known, the regulatory mechanism of the CaR function remains to be clarified. The purpose of the present study was to investigate the effect of caveolin-1 (Cav-1) on CaR-induced extracellular Ca(2+) influx by using acute caveolae disruption with Filipin or siRNA targeted to the Cav-1 in human umbilical vein endothelial cells (HUVECs). Intracellular Ca(2+) concentration ([Ca(2+)](i)) was detected by Fura-2/AM loading. The results showed that different concentrations of extracellular Ca(2+) failed to increase [Ca(2+)](i), while the CaR agonist Spermine (2 mmol/L) resulted in an increase in [Ca(2+)](i) that was diminished in buffer without Ca(2+) (P<0.05). No matter in buffer with or without 2 mmol/L Ca(2+), the [Ca(2+)](i) increase induced by Spermine in HUVECs was abolished after inhibition of CaR by a negative allosteric modulator Calhex231 (1 μmol/L) (P<0.05), conversely, the effect of Spermine on the increase in [Ca(2+)](i) in HUVECs was further augmented after acute caveolae disruption with Filipin (1.5 μg/mL) or transfection with siRNA targeted to the Cav-1 (P<0.05). This indicated that Cav-1 produced an inhibition of CaR-induced extracellular Ca(2+) influx. As to the biological mechanism of Cav-1-induced inhibition, immunofluorescence technique showed that both CaR and Cav-1 were present in HUVECs, and confocal microscopy supported the co-localization of CaR and Cav-1 on the plasma membrane. Functionally, the Cav-1 protein expression was decreased in HUVECs transfected with siRNA targeted to the Cav-1 (P<0.05); simultaneously, the CaR membrane protein expression was decreased (P<0.05), whereas CaR total protein level was unaffected (P>0.05). In conclusion, the present study suggests that CaR and Cav-1 co-localize on the plasma membrane in HUVECs and CaR-induced Ca(2+) influx is down-regulated by binding with Cav-1, and the mechanism involves the effect of Cav-1 on CaR localization on the plasma membrane and attenuating the CaR response to the agonist.

Association of the tagging single nucleotide polymorphisms in transforming growth factor beta-1 gene with hypertension in the Han nationality population in Xinjiang / 中华心血管病杂志

<p><b>OBJECTIVE</b>Essential hypertension (EH) was a complex disease resulted from the interaction of cumulative effect of multiple genetic and environment factors. The relationship between the genetic polymorphisms in the transforming growth factor-beta1 (TGF-beta1), the blood levels and EH have been investigated, but the conclusions were different. Therefore, we investigate the relationship between the tagging single nucleotide polymorphisms (tSNPs) (rs1800469, rs2241716, rs11466345, rs2241715, rs4803455) in TGF-beta1 gene, blood levels and EH in the Han nationality population in Xinjiang, to clarity the pattern of linkage disequilibrium (LD) and the feature of the structure of haplotype.</p><p><b>METHODS</b>Based on the case-control study,we selected 732 (365 EH patients,367 controls) Han Chinese population from the Boertonggu countryside of Shawan region in the Xinjiang Uygur Autonomous Region of China by random cluster sampling. After questionnaire and physical examination, we collected blood samples, and the blood levels of TGF-beta1 were quantified using sandwich ELISA. The polymorphisms of TGF-beta1 gene in the study groups were detected with SNaPshot system. The case-control study in a large group was carried out separately for each of the tSNP and followed up by haplotypes analyses to determine the relation between tSNPs of TGF-beta1 gene and EH in the Han population.</p><p><b>RESULTS</b>(1) The frequencies of alleles A, G of rs11466345 of TGF-beta1 gene in EH group and control group were as follows: 69.7%, 30.3%, 74.4%, 25.6%, respectively. It was demonstrated that the G allele of the rs11466345 polymorphism occurred at a significantly higher frequency in EH patients than in healthy controls (30.3% vs. 25.6%, P < 0.05). The rs11466345G-allele carriers had a significantly increased risk of EH compared to rs11466345A-allele carrier (OR = 1.261; P < 0.05). The frequencies of genotypes and alleles of the other tSNPs of TGF-beta1 gene had no difference between EH patients and controls (P > 0.05). (2)Except the site of rs11466345, the other tSNPs were in strong LD, and no statistical differences were observed in haplotypes distribution in the followup study between case-control groups (P > 0.05). (3) There were no difference of TGF-beta1 levels between the different genotypes and alleles in tSNPs of TGF-beta1 gene (P > 0.05).</p><p><b>CONCLUSIONS</b>(1) These results suggested that TGF-beta1 gene rs11466345 G allele was likely to be a genetic susceptibility factor for EH in the Xinjiang Han population, the other tSNPs perhaps had no association with EH of in the study groups. (2) Except rs11466345, the other tSNPs were in strong LD, and the haplotypes reconstructed by tSNPs might not be associated with EH in the Han nationality populations. (3) There was no association between the tSNP of TGF-beta1 gene and TGF-beta1 blood levels in the Xinjiang Han nationality population.</p>

Interaction between TGF-beta1/Smad pathway and ERK pathway in vascular smooth muscle cells / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate if the interaction between TGF-beta1/Smad pathway and ERK pathway in vascular smooth muscle cells exists.</p><p><b>METHODS</b>The rat arota was removed. The primary VSMC were isolated and cultured in vitro, then the VSMC were divided into four groups: (1) control group, (2) (TGF-beta1 group, (3) ERK blocking agent group, (4) TGF-beta1 + ERK blocking agent group. The expression of Smad2/3, ERK1/2 proteins, the content of phosphorylated ERK1/2 and Smad2/3 proteins were detected by Western blot, and the expression of Smad2/3 mRNA was detected by reverse transcription-polymerase chain reaction(RT-PCR) .</p><p><b>RESULTS</b>(1) In contrast to control group, the content of phosphorylated Smad2/3 and phosphorylated ERK1/2 proteins in TGF-beta1 group was increased (P < 0.05), that in ERK blocking agent group was decreased (P < 0.05). There was no difference between control group and TGF-beta1 + ERK blocking agent group. Compared with TGF-beta1 group, the contents of phosphorylated Smad2/3 and phosphorylated ERK1/2 proteins in TGF-beta1 + ERK blocking agent group was decreased (P < 0.05). There was no difference in the expression of Smad2/3 and ERK1/2 proteins among different groups. (2) There were no differences in expression of Smad2 and Smad3 mRNA among different groups.</p><p><b>CONCLUSION</b>(1) TGF-beta1 can induce Smad2/3 proteins to be phosphorylated dependent on the activated ERK pathway. (2) ERK pathway does not effect the expression of Smad2/3 at the level of protein and mRNA.</p>