Biomedical subjects

Yu Sun

Publications and source records attributed to Yu Sun.

At least 37 records · Page 2Linked to original sources

PubMed2006

Expression of hiwi gene in human gastric cancer was associated with proliferation of cancer cells.

Stem cell genetics research may be critical to our understanding of carcinogenesis, as both stem cells and cancer cells possess the ability to self-renew. Recent discoveries have indicated that the piwi family of genes plays an essential role in stem cell self-renewal in diverse organisms. The hiwi gene, the human homolog of the piwi family, participates in germ cell proliferation and its overexpression may cause the development of germ cell malignancy, but its expression and function in epithelial solid cancers have not been explored. In the present study, we investigated whether there was an association between hiwi expression and human gastric cancer and its potential mechanism. RT-PCR findings demonstrated that hiwi was expressed in different gastric cancer cell lines. To identify the HIWI protein in gastric cancer, we developed a specific monoclonal antibody against HIWI and immunohistochemistry was performed on various gastric tissues. We found that the expression ratio of hiwi in normal gastric tissues, atrophic gastritis, intestinal metaplasia and gastric cancers was 10% (5/50), 36% (18/50), 36% (18/50) and 76% (38/50), respectively, which was consistent with precancerous development. Notably, the expression pattern of hiwi in gastric cancer tissues was similar to that of Ki67, which was used as a marker of proliferation. Moreover, the suppression of hiwi by antisense or RNAi inhibited the growth of gastric cancer cells and induced cell cycle arrest in G2/M phase. These results suggest that hiwi may be involved in the development of gastric cancer and is a potential target for cancer therapy.

Antibodies, Monoclonal↗

PubMed2006

Comparison of implicit solvent models for the simulation of protein-surface interactions.

Empirical force field-based molecular simulations can provide valuable atomistic-level insights into protein-surface interactions in aqueous solution. While the implicit treatment of solvation effects is desired as a means of improving simulation efficiency, existing implicit solvent models were primarily developed for the simulation of peptide or protein behavior in solution alone, and thus may not be appropriate for protein interactions with synthetic material surfaces. The objective of this research was to calculate the change in free energy as a function of surface-separation distance for peptide-surface interactions using different empirical force field-based implicit solvation models (ACE, ASP, EEF1, and RDIE with the CHARMM 19 force field), and to compare these results with the same calculations conducted using density functional theory (DFT) combined with the self-consistent reaction field (SCRF) implicit solvation model. These comparisons show that distinctly different types of behavior are predicted with each implicit solvation method, with ACE providing the best overall agreement with DFT/SCRF calculations. These results also identify areas where ACE is in need of improvement for this application and provide a basis for subsequent parameter refinement.

Computer Simulation↗

PubMed2006

Bone morphogenetic protein 4 mediates bile duct ligation induced liver fibrosis through activation of Smad1 and ERK1/2 in rat hepatic stellate cells.

Bone morphogenetic proteins (BMPs) are the important cytokine involving in cell differentiation especially in bone morphogenesis. Hepatic stellate cells (HSCs) undergo a trans-differentiation during their activation after liver injury. Although it has been demonstrated that BMP2 and BMP4 significantly increased the abundance of smooth muscle alpha actin (alpha-SMA) in cultured HSCs, the expression of BMPs has not been examined during the activation of HSCs. In current study, we documented the expression of BMP4 in bile duct ligation (BDL) rats and HSCs in culture. We have found that the expression of BMP4 was significantly elevated in the liver of BDL rats. The increase in BMP4 protein showed two peaks during 6 weeks after BDL. The expression and phosphorylation of Smad1, ERK1/2 and p38 were also elevated after BDL. Moreover, there was a gradual elevation of BMP4 mRNA abundance during 24 days' in vitro culture of HSCs. Furthermore, BMP4 stimulated phosphorylation of Smad1 and ERK1/2 in HSCs. In conclusion, BMP4 expression was significantly increased in the liver of BDL rats and HSCs in culture. These findings indicate that BMP4 may mediate HSC activation through activation of Smad1 and ERK1/2.

Actins↗

PubMed2006

Vascular endothelial growth factor165-regulated nasopharyngeal carcinoma cell lines invasion and migration involve expression and activation of matrix metalloproteinase-2.

The effect of vascular endothelial growth factor (VEGF) overexpression on matrix metalloproteinase-2 (MMP-2) in nasopharyngeal carcinoma (NPC) cells in vitro and the possible mechanism involved were investigated, and the correlation between the expression of VEGF and MMP-2 in NPC evaluated. The NPC cells were transfected with PAd-trackVEGF165 plasmid. The expression levels of VEGF and MMP-2 mRNA and protein in NPC cells were detected by semi-quantitative RT-PCR and Western blot respectively. It was found that the expression of VEGF and MMP-2 mRNA and protein was significantly increased in NPC cells after transfection of VEGF165. It was concluded that the expression of VEGF was correlated to the in vitro invasion of NPC cells, and the induction of MMP-2 by VEGF was a key process of NPC cell invasion.

Cell Line, Tumor↗

PubMed2006

Mechanical analysis of chorion softening in prehatching stages of zebrafish embryos.

During early development, the chorion envelope of the zebrafish embryo undergoes a thinning process called "chorion softening," which has so far only been characterized chemically. In this study, a micromechanical force sensing system was used to characterize and quantitate mechanical modifications of the zebrafish embryo chorion during early development. Quantitative relationships between applied forces and chorion structural deformations were established at various embryonic stages. The measured penetration force into the chorion at the blastula stage was 1.3-fold greater than those at the prehatching stage. Furthermore, chorion elastic modulus values were determined by using a biomembrane elastic model. The elastic modulus of the chorion at the blastula stage was 1.66-fold greater than that at the prehatching stage, thus indicating that the chorion envelope become mechanically "softened" at the prehatching stage. The experimental results quantitatively describe "chorion softening," which is most likely due to proteolytic activities at the prehatching stage. Gradual chorion softening during embryonic development was also artificially achieved by treating blastula chorion with pronase, a proteolytic enzyme. The forces required to penetrate the pronase-treated chorion were similar to those at the prehatching stage. This similarity suggests that "chorion softening" may be induced by the release of protease from the embryos, and the chemical nature of the process involves proteolytic fragmentation of the ZP2 protein.

Animals↗

PubMed2006

Structural and functional roles for beta-strand 7 in the alpha-crystallin domain of p26, a polydisperse small heat shock protein from Artemia franciscana.

Oviparous development in the extremophile crustacean, Artemia franciscana, generates encysted embryos which enter a profound state of dormancy, termed diapause. Encystment is marked by the synthesis of p26, a polydisperse small heat shock protein thought to protect embryos from stress. In order to elucidate structural/functional relationships within p26 and other polydisperse small heat shock proteins, and to better define the protein's role during diapause, amino acid substitutions R110G, F112R, R114A and Y116D were generated within the p26 alpha-crystallin domain by site-directed mutagenesis. These residues were chosen because they are highly conserved across species boundaries, and molecular modelling indicates that they are part of a key structural interface between dimers. The F112R mutation, which had the greatest impact on oligomerization, placed two charged residues at the p26 dimer-dimer interface, demonstrating the importance of beta-strand 7 in tetramer formation. All mutated versions of p26 were less able than wild-type p26 to confer thermotolerance on transformed bacteria and they exhibited diminished chaperone action in three in vitro assays; however, all variants retained protective activity. This apparent stability of p26 may, by prolonging effective chaperone life in vivo, enhance embryo stress resistance. All substitutions modified p26 intrinsic fluorescence, surface hydrophobicity and secondary structure, and the pronounced changes in variant R114A, as indicated by these physical measurements, correlated with the greatest loss of function. Although mutation R114A had the greatest effect on p26 chaperoning, it had the least on oligomerization. These results demonstrate that in contrast to many other small heat shock proteins, p26 effectiveness as a chaperone is independent of oligomerization. The results also reinforce the idea, occasioned by modelling, that R114 is removed slightly from dimer-dimer interfaces. Moreover, beta-strand 7 is shown to have an important role in oligomerization of p26, a function first proposed for this structural element upon crystallization of wheat Hsp16.9, a small heat shock protein with different quaternary structure.

Amino Acid Sequence↗

PubMed2006

Inhibition of apoptosis by p26: implications for small heat shock protein function during Artemia development.

p26, an abundantly expressed small heat shock protein, is thought to establish stress resistance in oviparously developing embryos of the crustacean Artemia franciscana by preventing irreversible protein denaturation, but it might also promote survival by inhibiting apoptosis. To test this possibility, stably transfected mammalian cells producing p26 were generated and their ability to resist apoptosis induction determined. Examination of immunofluorescently stained transfected 293H cells by confocal microscopy demonstrated p26 is diffusely distributed in the cytoplasm with a minor amount of the protein in nuclei. As shown by immunoprobing of Western blots, p26 constituted approximately 0.6% of soluble cell protein. p26 localization and quantity were unchanged during prolonged culture, and the protein had no apparent ill effects on transfected cells. Molecular sieve chromatography in Sepharose 6B revealed p26 oligomers of about 20 monomers, with a second fraction occurring as larger aggregates. A similar pattern was observed in sucrose gradients, but overall oligomer size was smaller. Mammalian cells containing p26 were more thermotolerant than cells transfected with the expression vector only, and as measured by annexin V labeling, Hoescht 33342 nuclear staining and procaspase-3 activation, transfected cells effectively resisted apoptosis induction by heat and staurosporine. The ability to confer thermotolerance and limit heat-induced apoptosis is important because Artemia embryos are frequently exposed to high temperature in their natural habitat. p26 also blocked apoptosis in transfected cells during drying and rehydration, findings with direct relevance to Artemia life history characteristics because desiccation terminates cyst diapause. Thus, in addition to functioning as a molecular chaperone, p26 inhibits apoptosis, an activity shared by other small heat shock proteins and with the potential to play an important role during Artemia embryo development.

Animals↗

PubMed2006

Mechanisms controlling embryonic stem cell self-renewal and differentiation.

Embryonic stem (ES) cells are pluripotent cells with indefinite replication potential and ability to differentiate into all types of cells. An understanding of the regulatory mechanisms responsible for pluripotency in ES cells is critical for realizing their potential in regenerative medicine and science. Cross-species studies on ES cells have identified pathways and networks that are either fundamental to or species-specific for self-renewal and differentiation. Although pluripotency as an essential function in multicellular organisms is conserved through evolution, mechanisms primed for differentiation contribute substantially to the differences among stem cells derived from different tissues or species. Transcriptome mapping analysis has determined the chromosomal domains of gene coexpression patterns specific to the ES state and demonstrated that regulation of ES cell development is operative at both the local chromosomal domain level and global level. Combinatorial signals from multiple pathways regulate the expression of key intrinsic factors critical for ES cell fate determination. The regulatory core formed by Oct4, Sox2, and Nanog, in particular, activates genes critical for self-renewal and represses genes initiating differentiation, controlling ES cell pluripotency. Here, we review recent findings on mechanisms controlling ES cell development. By integrating data from different sources, we present a global picture of how ES cells reach the decision of self-renewal or differentiation.

Animals↗

PubMed2006

[Prognostic value of plasma brain natriuretic peptide and C-reactive protein in patients with acute coronary syndromes underwent percutaneous coronary intervention].

OBJECTIVE: To evaluate the prognostic value of plasma brain natriuretic peptide (BNP) and C-reactive protein (CRP) in patients with acute coronary syndromes (ACS) underwent percutaneous coronary intervention (PCI). METHODS: Patients with ACS underwent PCI in our hospital from December 2004 to September 2005 were included in this study. Plasma BNP (n = 189) and CRP (n = 141) were measured at a median of (34.2 +/- 16.3) hours from symptom onset, total mortality and the risk for major adverse cardiac events (MACE, including death, recurrent MI, recurrent angina, heart failure, readmission for any reason) at 30 days and at 3 months was analyzed. RESULTS: Patients were divided into 4 groups according to their BNP levels (BNP 100 ng/L to 300 ng/L to 600 ng/L) and the 3-month mortality was 0%, 1.4%, 7.7%, 48.3% and 3-month incidence of MACE was 7.9%, 17.1%, 57.7%, 79.3% respectively. Multivariate logistic regression analyses showed that the plasma BNP level predicted 30-day (r = 0.8515, P < 0.01) and 3-month (r = 0.9201, P < 0.01) mortality and 30-day (r = 0.7066, P < 0.01) and 3-month (r = 0.7090, P < 0.01) incidence of MACE independent of other known prognostic factors such as age, gender, family heredity, hypercholesterolemia diabetes, hypertension, smoking and LVEF. Patients were divided into 3 groups according to their CRP levels (CRP 8.0 mg/L to 32.0 mg/L) and 3-month mortality was 2.7%, 7.7% and 28.6% and 3-month incidence of MACE was 28.4%, 41.0% and 60.7% respectively. CRP predicted 30-day (r = 0.5882, P = 0.0044) and 3-month (r = 0.5235, P = 0.0038) mortality independent of traditional risk factors, and predicted 30-day (r = 0.2705, P = 0.0380) and 3-month (r = 0.2290, P = 0.0429) incidence of MACE after adjustment for patient age. CRP lost its predictive value after BNP was introduced into the model, while BNP was still an independent predictor for mortality and incidence of MACE at 30 days and 3 months in ACS patients underwent PCI. CONCLUSION: Both plasma BNP and CRP are good predictors for early mortality and MACE incidence in ACS patients underwent PCI.

Acute Coronary Syndrome↗

PubMed2006

[Expression and purification of human MT-2a fusion protein in prokaryotic cells and preparation of its antiserum].

AIM: To express and purify human MT-2a in prokaryotic cells and to prepare the MT-2a-specific rabbit antiserum. METHODS: GST-MT-2a fusion protein was expressed after IPTG induction and further purified with Glutathione Sepharose 4B. Then the purified GST-MT-2a fusion protein was used to immunize New Zealand rabbits. The titer and specificity of rabbit antiserum were evaluated by double immunodiffusion, ELISA and Western blot. RESULTS: GST-MT-2a fusion protein was highly expressed. The final yield of the pure GST-MT-2a was about 38 mg per liter of bacterial culture. Its antiserum with high specificity and potency was also obtained. CONCLUSION: The successful expression of GST-MT-2a fusion protein in E. coli and the preparation of MT-2a specific rabbit antiserum will be valuable for the study on the function of human MT-2a.

Antibody Specificity↗

PubMed2006

[Detection of respiratory syncytial virus in nasopharyngeal aspirates of children by using real-time polymerase chain reaction].

OBJECTIVE: Human respiratory syncytial virus (hRSV) is the leading cause of acute upper and lower respiratory tract infections in infants and young children worldwide. Pediatric RSV disease claims more than 1 million lives annually. With the rapid development of specific anti-RSV agents and the spread of respiratory infections, RSV detection techniques with higher sensitivity, specificity and quicker performance are badly needed. This study was designed to develop a real-time polymerase chain reaction (PCR) for detection of RSV in nasopharyngeal aspirates. METHODS: (1) The TaqMan probe and primers of real-time PCR for RSV subgroup A and subgroup B detection were designed from the conserved region in N protein encoding gene, respectively. The sensitivity of real-time PCR was evaluated by using the virus with known amount of PFU. The specificity of real-time PCR for RSV detection was assessed by cross testing 10 isolates of strains A, 10 isolates of strains B, and by testing a variety of other respiratory viruses positive samples. (2) Sixty-one stored RSV positive respiratory samples and 103 nasopharyngeal aspirates were detected by real-time PCR, virus isolation, immunofluorescence assay (IFA), and nested-PCR. RESULTS: (1) The sensitivity of the real-time PCR developed in this study for RSV subgroup A detection was 5.25 pfu, and for subgroup B was 3.75 pfu, the same as that of nested-PCR. (2) No positive results were found in cross testing of other viruses positive specimens. (3) Twenty-seven out of 30 (90%) of RSV A stored samples and 27 out of 31 (87.1%) of RSV B stored samples were positive by the real-time PCR. (4) Thirty-five (34.0%) out of the 103 specimens were found RSV positive by real-time PCR (7 of them were subgroup A and 28 subgroup B); 31 (30.1%) specimens were positive by nested-PCR (6 of them were subgroup A and 25 subgroup B); 22 (21.4%) were found positive for RSV with IFA (5 of them were subgroup A and 17 subgroup B); RSV was isolated from 9 (8.7%) specimens (6 of them were subgroup A and 3 subgroup B). All the specimens found to be negative by real-time PCR were negative by rest of the methods used in this study. CONCLUSION: The real time PCR method developed in this project with the TaqMan probe and primers is sensitive and specific for detecting RSV subgroup A and B in nasopharyngeal aspirates.

Child↗

PubMed2006

[Influence of different doses of porcine pulmonary on the therapeutic effects in rats with oleic acid induced acute lung injury].

OBJECTIVE: To investigate the therapeutic effects and dose effect relationship of intratracheal instillation of different doses of porcine pulmonary surfactant (PPS) in rats with oleic acid (OA) induced acute lung injury (ALI). METHODS: Arterial blood gases and respiratory rate during the experiments, survival rate, lung index, total protein (TP) content in bronchoalveolar lavage fluid (BALF), tumor necrosis factor-alpha (TNF-alpha) level in plasma, light microscopy examination of lung specimens after the experiments were determined and performed in control group, OA (0.2 ml/kg) + saline, OA + PPS 50 mg/kg, OA+PPS 80 mg/kg, OA+PPS 100 mg/kg, OA+PPS 150 mg/kg, OA+PPS 200 mg/kg groups, respectively. RESULTS: In PPS 50 mg/kg group, arterial blood gases were improved and respiratory rate was reduced during the first 2 hours (P<0.05). Arterial blood gases and reduced breath rates respiratory rate were not improved in other PPS treatment groups but 4 hours-survival rate was lowered, lung index was decreased, protein content s in BALF and TNF-alpha level in serum were lowered, and pathological changes were ameliorated compared with group given saline after OA, especially in high dosage of PPS (150-200 mg/kg) group (P<0.05). CONCLUSION: Administration of PPS via trachea provides obvious effects on respiratory functions in rats with OA induced ALI, moreover PPS (> or =80 mg/kg) alleviates lung injury. There is no dose-effect relationship of PPS in PPS-treatment groups.

Acute Lung Injury↗

PubMed2006

[Study on the correlation between the expressions of nm23H1 mRNA, VEGF-C mRNA and lymphatic metastases, survival rate with gastric cancer].

The correlations between the expression of nm23H1 mRNA,VEGF-C mRNA, VEGFR-3 and neoangiogenesis, hyperplasia of micro-lymphatic, tumor metastases in gastric cancer were studied, the results supplied an experimental foundation for clinical treatment and prognosis. All the specimens were marked by VEGFR-3 antibody, the expressions of nm23H1 mRNA, VEGF-C mRNA were detected in 78 cases of gastric cancer in situ hybridization with EnVision and Leica-Qwin computer image analysis system. The Weidner's highest vessel density counting method was used to analyse micro-lymphatics count (MLC) of the specimens, and the patients' viability after operation was investigated. The positive expression of nm23H1 mRNA in gastric cancer was 69.23% (54 cases). There was negative correlation between the positive expression of nm23H1 mRNA and lymph node metastasizing, TNM staging, MLC (P < 0.01 or P < 0.05). The expression of VEGF-C mRNA was 46.15% (36 cases). It was positive related to the lymph node metastasis, TNM stages, MLC in gastric cancer (P < 0.01 or P < 0.05), and was significantly different compared with adjacent nontumorous tissue (P < 0.01 or 0.05). The expression of nm23H1 in stage I and II gastric cancer was high, while in stage III and IV the expression was lower or even none. The MLC (8.37 +/- 2.29/mm2) in gastric cancer was higher than that in adjacent nontumorous tissue (4.82 +/- 3.48/mm2), which has statistical significance (P < 0.05). There was negative correlation between the expression of nm23H1 mRNA and VEGFR-3 (p < 0.05, r = 0.8479), but positive correlation between VEGF-C mRNA and VEGFR-3 (P < 0.05, r = 0.8362). The MLC (10.82 +/- 2.51/mm2) in those who died in five years (48 cases) was higher than that (6.53 +/- 2.09/mm2) in those who were still alive, the difference has statistical significance (P < 0.05). In different tumor pathology grading, different differentiation, the nm23H1 positive expression is significantly different (P < 0.05). Higher the nm23H1 expressed, lower the tumor lymph metastasized, but the viability rate was higher, so the nm23H1 gene was thought to have the effect of suppressing gastric cancer occurring and lymph metastasizing. Higher the VEGF-C mRNA expressed, higher the tumor lymph metastasized, but the viability rate was lower. There is close correlation between the VEGFR-3 expression and gastric cancer lymph metastasizing. The higher MLC level indicated neoangiogenesis in gastric cancer. VEGF-C promote neoangiogenesis induced by tumor and play an important role in lymph metastasizing.

Adult↗

PubMed2006

[Comparative study of uptake and washout of 99mTcn(NOEt)2 with 99mTc-MIBI in human nasopharyngeal carcinoma cell line CNE].

OBJECTIVE: To determine the cellular kinetics of 99mTc-bis {N-ethoxy-N-ethyl dithiocarbamato-nitrido [N(NOEt)2]} in human nasopharyngeal carcinoma CNE cells line and to compare it with the cellular kinetics of 99mTc-methoxyisobutylisonitrile (MIBI) in the same conditions; to define the possible clinical application value of 99mTcN(NOEt)2 in nasopharyngeal carcinoma imaging. METHOD: 99mTcN(NOEt)2 or 99mTc-MIBI were incubated with CNE cells at 37degrees C, 22 degrees C, at different time points after incubation, the uptake and washout characteristics of radiotracers in CNE cells were investigated and compared. RESULT: The maximum uptake ratio of 99mTcN(NOEt)2 in CNE cells was 43.15%, that of 99mTc-MIBI was 11.08% (P < 0.01). The uptake of 99mTcN(NOEt)2 after 5 min incubation in CNE cells was 63% of total uptake, uptake of 99mTc-MIBI was 48% of total uptake (P < 0.05); 1 h after removal of the unbound tracer, 63.92% of the total uptake of 99TcN(NOEt)2 was retained in the CNE cells, 53. 97% of 99mTc-MIBI was retained (P < 0.05); not like 99mTc-MIBI, the cellular kinetics of 99mTcN (NOEt)2 were similar at 37 degrees C and 22 degrees C ( P > 0.05). CONCLUSION: 99mTcN(NOEt)2 may be a gamma imaging agent better than 99mTc-MIBI for nasopharyngeal carcinoma imaging. 99mTcN(NOEt)2 is a potential human nasopharyngeal carcinoma imaging agent.

Cell Line, Tumor↗

PubMed2005

Isolation and characterization of a sodium-dependent phosphate transporter gene in Dunaliella viridis.

A sodium-dependent phosphate transporter gene, DvSPT1, was isolated from a cDNA library using a probe derived from a subtracted cDNA library of Dunaliella viridis. Sequencing analyses revealed a cDNA sequence of 2649 bp long and encoded an open-reading frame consisting of 672 amino acids. The deduced amino acid sequence of DvSPT1 exhibited 31.2% identity to that of TcPHO from Tetraselmis chui. Hydrophobicity and secondary structure prediction revealed 11 conserved transmembrane domains similar to those found in PHO89 from Saccharomyces cerevisiae and PHO4 from Neurospora crassa. Northern blot analysis indicated that the DvSPT1 expression was induced upon NaCl hyperosmotic stress or phosphate depletion. Functional characterization in yeast Na+ export pump mutant G19 suggested that DvSPT1 encoded a Na+ transporter protein. The gene sequence of GDvSPT1 (7922 bp) was isolated from a genomic library of D. viridis. Southern blot analysis indicated that there exist at least two homologous genes in D. viridis.

Amino Acid Sequence↗

PubMed2005

Prediction of the orientations of adsorbed protein using an empirical energy function with implicit solvation.

When simulating protein adsorption behavior, decisions must first be made regarding how the protein should be oriented on the surface. To address this problem, we have developed a molecular simulation program that combines an empirical adsorption free energy function with an efficient configurational search method to calculate orientation-dependent adsorption free energies between proteins and functionalized surfaces. The configuration space is searched systematically using a quaternion rotation technique, and the adsorption free energy is evaluated using an empirical energy function with an efficient grid-based calculational method. In this paper, the developed method is applied to analyze the preferred orientations of a model protein, lysozyme, on various functionalized alkanethiol self-assembled monolayer (SAM) surfaces by the generation of contour graphs that relate adsorption free energy to adsorbed orientation, and the results are compared with experimental observations. As anticipated, the adsorbed orientation of lysozyme is predicted to be dependent on the discrete organization of the functional groups presented by the surface. Lysozyme, which is a positively charged protein, is predicted to adsorb on its 'side' on both hydrophobic and negatively charged surfaces. On surfaces with discrete positively charged sites, attractive interaction energies can also be obtained due to the presence of discrete local negative charges present on the lysozyme surface. In this case, 'end-on' orientations are preferred. Additionally, SAM surface models with mixed functionality suggest that the interactions between lysozyme and surfaces could be greatly enhanced if individual surface functional groups are able to access the catalytic cleft region of lysozyme, similar to ligand-receptor interactions. The contour graphs generated by this method can be used to identify low-energy orientations that can then be used as starting points for further simulations to investigate conformational changes induced in protein structure following initial adsorption.

Adsorption↗

PubMed2005

Asymmetric distribution of EGFR receptor during mitosis generates diverse CNS progenitor cells.

It has been debated whether asymmetric distribution of cell surface receptors during mitosis could generate asymmetric cell divisions by yielding daughters with different environmental responsiveness and, thus, different fates. We have found that in mouse embryonic forebrain ventricular and subventricular zones, the EGFR can distribute asymmetrically during mitosis in vivo and in vitro. This occurs during divisions yielding two Nestin+ progenitor cells, via an actin-dependent mechanism. The resulting sibling progenitor cells respond differently to EGFR ligand in terms of migration and proliferation. Moreover, they express different phenotypic markers: the EGFRhigh daughter usually has radial glial/astrocytic markers, while its EGFRlow sister lacks them, indicating fate divergence. Lineage trees of cultured cortical glioblasts reveal repeated EGFR asymmetric distribution, and asymmetric divisions underlie formation of oligodendrocytes and astrocytes in clones. These data suggest that asymmetric EGFR distribution contributes to forebrain development by creating progenitors with different proliferative, migratory, and differentiation responses to ligand.

Actins↗

PubMed2005

[A prospective randomized comparison between with or without instrumentation in short-level anterior discectomy and autograft bone fusion].

OBJECTIVE: To evaluate anterior cervical plating in short-level anterior discectomy and autograft bone fusion. METHODS: Eighty-one patients who underwent one- and two-level anterior cervical discectomy and fusion were randomized to 2 groups, with or without instrumentation. Among them, 55 patients were followed up. The mean follow-up time was (22 +/- 7) months. Fusion rate, disc height and cervical lordotic alignment were assessed by radiographs. RESULTS: The improving rates were 68% in non-instrumented group and 58% in instrumented group, respectively (P > 0.05). The fusion rate was 93% in the non-instrumented group and 100% in the later one. The disc height was decreased (0.7 +/- 1.0) mm in the former group and increased (1.2 +/- 0.6) mm in the later one (P < 0.01). Although the postoperative cervical lordotic alignment was maintained better in instrumented group, the difference was not significant. CONCLUSION: Anterior cervical plating can make good influence on the result of anterior cervical discectomy and fusion in some degree.

Adult↗