[An analysis of the causes of titanium plates removal after rigid internal fixation for jaw fractures].
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Adult↗
Biomedical subjects
Yan Shen
Publications and source records attributed to Yan Shen.
[Protective immunoresponse to CVB3 induced by gene immunization with pcDNA3-VP1].
AIM: To induce Coxsackie virus B type 3 (CVB3)-specific immune response by using a DNA vaccine containing CVB3-VP1 and to observe its protection against CVB3 challenge. METHODS: The gene coding for VP1 was obtained by RT-PCR and then was cloned into plasmid pcDNA3 to construct pcDNA3-VP1. In-vitro expression of VP1 was performed by transfection of pcDNA3-VP1 into Hela cells. Expressed product was detected by ELISA. BALB/c mice were immunized intramuscularly with 50 microg DNA three times, and challenged by 5xLD(50) CVB3 four weeks after the last immunization. RESULTS: pcDNA3-VP1 had been constructed and the expression product was detected in the culture supernatant of Hela cells 24 hours after transfection. CVB3-specific IgM and IgG elicited in the mice immunized with pcDNA3-VP1 were significantly higher than those in the control mice immunized with pcDNA3. Specific proliferation of the splenic lymphocytes and activity of CVB3-specific CTLs from the pcDNA3-VP1 immunized mice were much stronger than those in the controls. pcDNA3-VP1 could protect 33.3% mice from lethal CVB3 challenge, while control mice only survived 6.7 days. Infiltration of inflammatory cells or unusual proliferation of connective tissue, indicating ongoing myocarditis or fibrosis, were not found in pcDNA3-VP1 immunized mice, but did exist in control mice. CONCLUSION: Intramuscular immunization with pcDNA3-VP1 may be a promising approach against CVB3 infection.
Animals↗
Mutation screen of the GABA(A) receptor gamma 2 subunit gene in Chinese patients with childhood absence epilepsy.
Childhood absence epilepsy (CAE) is considered to be a genetic disease, the genes responsible for which have not yet been identified. To investigate whether or not GABA(A) receptor gamma 2 subunit gene (GABRG2) is the susceptibility gene for CAE in the Chinese population, we screened 68 CAE patients of Han ethnicity from North China for mutations in the nine exons of GABRG2. Although we found no mutation in the exons of GABRG2, we did identify two single nucleotide polymorphisms (SNPs) in exon 3 and exon 5. Using the two SNPs as markers, we carried out a transmission/disequilibrium test (TDT) in 68 trios with CAE. TDT results showed that there were no significant discrepancies between the CAE patients and 'internal controls' in allele frequencies of the two SNPs. We postulate that the GABRG2 gene might be neither a susceptibility gene for CAE nor in linkage disequilibrium with disease-predisposing sites in the Chinese population.
Adolescent↗
Esophageal cancer in Chinese population: no polymorphism in codon 149 of P21(Waf1/Cip1) cyclin dependent kinase gene.
It has recently been suggested that people of the Indian population who carried the codon 149 polymorphism (GAT-->GGT) of P21(Waf1/Cip1) gene were more susceptible to esophageal cancer and oral cancer than the individuals without that polymorphism. Since esophageal cancer is a high incident neoplasm in China, we analysed the same codon of P21(Waf1/Cip1) in the Chinese population. Blood samples from 80 esophageal cancer patients and 80 normal blood donors were collected for DNA extraction. Methods of Polymerase Chain Reaction (PCR) and direct sequencing were used for detection of the polymorphism in codon 149 of P21(Waf1/Cip1). Bioinformatics analysis was also thoroughly performed for this gene. No polymorphism was found in all samples tested. Bioinformatics analysis revealed that the so-called polymorphism of codon 149 reported previously was a wrong one. In conclusion, no polymorphism exists in codon 149 of P21(Waf1/Cip1). It is not appropriate to use it as a susceptible site of the gene in cancer study.
Asian People↗
Gene expression profiling in developing human hippocampus.
The gene expression profile of developing human hippocampus is of particular interest and importance to neurobiologists devoted to development of the human brain and related diseases. To gain further molecular insight into the developmental and functional characteristics, we analyzed the expression profile of active genes in developing human hippocampus. Expressed sequence tags (ESTs) were selected by sequencing randomly selected clones from an original 3'-directed cDNA library of 150-day human fetal hippocampus, and a digital expression profile of 946 known genes that could be divided into 16 categories was generated. We also used for comparison 14 other expression profiles of related human neural cells/tissues, including human adult hippocampus. To yield more confidence regarding differential expression, a method was applied to attach normalized expression data to genes with a low false-positive rate (<0.05). Finally, hierarchical cluster analysis was used to exhibit related gene expression patterns. Our results are in accordance with anatomical and physiological observations made during the developmental process of the human hippocampus. Furthermore, some novel findings appeared to be unique to our results. The abundant expression of genes for cell surface components and disease-related genes drew our attention. Twenty-four genes are significantly different from adult, and 13 genes might be developing hippocampus-specific candidate genes, including wnt2b and some Alzheimer's disease-related genes. Our results could provide useful information on the ontogeny, development, and function of cells in the human hippocampus at the molecular level and underscore the utility of large-scale, parallel gene expression analyses in the study of complex biological phenomena.
Adult↗
Genome sequence of Shigella flexneri 2a: insights into pathogenicity through comparison with genomes of Escherichia coli K12 and O157.
We have sequenced the genome of Shigella flexneri serotype 2a, the most prevalent species and serotype that causes bacillary dysentery or shigellosis in man. The whole genome is composed of a 4 607 203 bp chromosome and a 221 618 bp virulence plasmid, designated pCP301. While the plasmid shows minor divergence from that sequenced in serotype 5a, striking characteristics of the chromosome have been revealed. The S.flexneri chromosome has, astonishingly, 314 IS elements, more than 7-fold over those possessed by its close relatives, the non-pathogenic K12 strain and enterohemorrhagic O157:H7 strain of Escherichia coli. There are 13 translocations and inversions compared with the E.coli sequences, all involve a segment larger than 5 kb, and most are associated with deletions or acquired DNA sequences, of which several are likely to be bacteriophage-transmitted pathogenicity islands. Furthermore, S.flexneri, resembling another human-restricted enteric pathogen, Salmonella typhi, also has hundreds of pseudogenes compared with the E.coli strains. All of these could be subjected to investigations towards novel preventative and treatment strategies against shigellosis.
Amino Acid Sequence↗
Three isoforms of annexin I are preferentially expressed in normal esophageal epithelia but down-regulated in esophageal squamous cell carcinomas.
The development and progression of human cancer are believed to be due to the alterations of multiple genes or/and their protein products. For identifying the proteins associated with esophageal cancer, we analysed the protein profiles of 24 pairs of esophageal squamous cell carcinomas/matched adjacent normal epithelia. Microdissection of routinely unstained frozen sections was performed to purify cancerous and epithelial cells. The protein expression profiles were obtained by two-dimensional electrophoresis. Selected proteins dysregulated in tumors were identified by MALDI-TOF-MS. Three isoforms of annexin I were detected in normal esophageal mucosa and down-regulated in esophageal squamous cell carcinomas. RT-PCR analysis showed annexin I mRNA levels were significantly reduced in 17 out of 24 carcinomas. Immunohistochemistry demonstrated that annexin I appeared strong positive in all normal epithelia layers except basal cells. In cancer tissues, decreased expression of annexin I was observed in 12 out of 16 well differentiated tumors, 16 out of 17 moderately differentiated tumors, and 3 out of 3 poorly differentiated tumors as compared with the corresponding normal esophageal epithelia. There was a significant correlation between annexin I expression and the status of tumor differentiation. Well differentiated tumors presented stronger immunohistochemical reaction than moderately and poorly differentiated tumors. These data suggested that there existed three different isoforms of annexin I in normal esophageal epithelia, which may be the results of post-translational modification. Down-expression of three annexin I isoforms was a frequent event in esophageal carcinogenesis.
Annexin A1↗
[Association analysis of childhood absence epilepsy by microsatellite DNA].
OBJECTIVE: To investigate whether or not the gamma-aminobutyric acid GABA receptor subtype Alpha genes GABRA5 and GABRB3 are associated with childhood absence epilepsy CAE . METHODS: Five microsatellite DNA 69CA 85CA 155CA1 155CA2 and A55CA1 adjacent to chromosome 15q11-15q13 were used as genetic markers. Fluorescence-based semi-automated genotyping technique was used in 90 CAE patients and 100 normal controls to conduct genotyping. Case-control study was used to do association analysis. RESULTS: In Chinese normal population the allele frequencies of the five microsatellite DNAs were in good agreement with Hardy- Weinberg equilibrium. The polymorphism information content PIC of the five microsatellite DNA were 0.47 0.82 0.66 0.86, and 0.86 respectively. The frequencies of some alleles of the 5 microsatellite DNAs in CAE patients were significantly higher than those in normal controls. CONCLUSION: Four of the five microsatellite DNAs are good genetic markers. GABA subtype Alpha genes GABRA5 and GABRB3 may be associated with the pathogenic mechanism of CAE.
Adolescent↗
Importance of FADD signaling in serum deprivation- and hypoxia-induced cardiomyocyte apoptosis.
Although cardiomyocyte (CM) apoptosis has been well described in both in vitro and in vivo models of ischemic heart disease, the intracellular pathways leading to CM death have not been fully characterized. To define the role of death receptor signaling in CM apoptosis, we constructed recombinant adenoviral vectors carrying wild-type (wt) or dominant negative (dn) forms of the death receptor adaptor protein FADD (Fas-associated death domain protein) and used these vectors to transduce rat neonatal CMs in models of hypoxia- and serum deprivation (SD)-induced apoptosis. The combination of SD and hypoxia induced rapid activation of caspase-3 and -8 as well as DNA fragmentation, reaching a plateau within 4-8 h. Adenoviral expression of FADD-dn inhibited caspase-8 activation as well as hypoxia/SD-induced apoptosis at 24 h in an moi (multiplicity of infection)-dependent manner. In contrast, adenoviral expression of FADD-wt increased apoptosis and caspase-3 activity in CMs under both normoxic and hypoxic conditions. Surprisingly, FADD-dn, as well as the specific caspase-8 inhibitor benzyloxycarbonyl-IETD-fluoromethylketone also inhibited the activation of caspase-9 and -3 in CMs subjected to hypoxia/SD. These data suggest a primary role for FADD/caspase-8 signaling that is necessary and sufficient for apoptosis of CMs subjected to hypoxia/SD.
Adaptor Proteins, Signal Transducing↗
Regulation of the mitochondrial checkpoint in p53-mediated apoptosis confers resistance to cell death.
The p53 tumor suppressor protein inhibits tumor formation, in part by inducing apoptosis, which is inhibited by anti-apoptotic Bcl-2 family members Bcl-2 and adenovirus E1B 19K. We have identified p53-apoptotic signaling events which are targeted for inhibition by E1B 19K. Apoptotic signaling by p53 induced a Bid-independent conformational change in Bax, a Bax-Bak interaction, release of cytochrome c and Smac/DIABLO from mitochondria, caspase-9 and -3 activation, cleavage of known caspase substrates, and apoptosis. When p53-dependent apoptosis was blocked by E1B 19K expression, E1B 19K bound Bak, and the Bax-Bak interaction was inhibited. Cytochrome c and Smac/DIABLO release from mitochondria was also inhibited in E1B 19K expressing cells and cells remained viable. After a prolonged p53 death stimulus, the inhibition of the mitochondrial death checkpoint by E1B 19K failed, and cytochrome c and Smac/DIABLO were released from mitochondria, and became degraded. Despite this eventual failure to inhibit the mitochondrial checkpoint, caspase-9 and -3 were not activated, and cells remained viable even upon treatment with an exogenous death stimulus. Thus, p53 induces apoptosis in part through Bax and Bak, and even an incomplete inhibition of this mitochondrial checkpoint may be sufficient to confer resistance to cell death.
Adenovirus E1B Proteins↗
MECP2 gene mutation analysis in Chinese patients with Rett syndrome.
Rett syndrome (RTT) is a progressive neurodevelopmental disorder that affects almost exclusively girls. Mutations in the X-linked methyl-CpG-binding protein 2 gene (MECP2) have been found to be a cause. In order to study the spectrum of MECP2 mutations in Chinese patients, we employed PCR and sequencing of the coding region of MECP2 gene in 31 Chinese cases of classical sporadic RTT. Mutations in MECP2 were found in about 55%. Twelve different mutations in exon 3 were identified in 17 of these 31 patients; two of these are novel. A novel missense variant was detected in the C-terminal region in a patient and her father who was normal. In addition, there was a single nucleotide variant in the 3'UTR.
Amino Acid Substitution↗
Identification and comparative analysis of differentially expressed proteins in rat striatum following 6-hydroxydopamine lesions of the nigrostriatal pathway: up-regulation of amyloid precursor-like protein 2 expression.
During neurodegenerative processes, cascades of degeneration and subsequent regeneration are triggered. However, the molecular nature of the factors involved in the neurodegeneration of the CNS remains largely unknown. In this study, the variations of protein expression in the striatum of adult Sprague-Dawley rats following 6-hydroxydopamine lesions were investigated, in order to better understand the molecular events occurring in the denervated target tissue. The rat striatum, ipsilateral to the lesion was analysed by two-dimensional gel electrophoresis followed by matrix assisted laser desorption/ionization-time of flight mass spectrometry. Seven proteins were up-regulated (188.1-750% compared to control) in response to the lesion: amyloid precursor-like protein 2 (APLP2), kininogen, glucokinase, tropomyosin alpha chain, type brain-1 and calpactin I light chain; whilst four proteins, neural epidermal growth factor-like 2, minichromosome maintenance 6, and thyroid hormone receptor beta-2, were down-regulated (to between 36% and 59% of levels in sham-operated controls). Three proteins that did not match with available data in the SWISS-PROT protein database were also determined. Immunohistochemical analysis demonstrated colocalization of APLP2 and tyrosine hydroxylase in the nigral neurons. Moreover, reduction of APLP2-positive neurons in the substantia nigra pars compacta as well as the increases in the substantia nigra pars reticulata and in the striatum were observed. Furthermore, the conditioned medium of the Chinese hamster ovary cells over-expressing APLP2-751 (chondroitin sulphate-modified), but not APLP2-763 (nonchondroitin sulphate-modified), was able to increase the number of the tyrosine hydroxylase-positive neurons in fetal mesencephalic cultures. These results suggest that the expression of APLP2, a protein that has been thought to be associated with Alzheimer's disease, is up-regulated in the striatum following dopaminergic denervation. They also support the view that chondroitin sulphate-modified APLP2 protein may play an important role in the dopaminergic nigrostriatal system.
Adrenergic Agents↗
[Orthotopic liver transplantation for end-stage liver diseases in 71 cases].
OBJECTIVE: To assess the role of orthotopic liver transplantation (OLT) in the treatment of end-stage liver diseases and to discuss the experience of the operation. METHODS: Retrospective analysis of clinical data of 71 cases of liver transplantation was performed in our hospital from April 1993 to August 2001. RESULTS: One year survival rate of recipients with benign hepatic disease was over 75%. The survival time and life quality of malignant recipients were also improved. Lamivudine monotherapy during the operation period could reduce HBV reinfection rate. The practice of OLT without veno-venous bypass (VVB) was associated with a shorter operating time, less hemorrhape, and thus less blood transfusion during the operation compared with standard technique of OLT with routine use of VVB. The occurrence rate of biliary complications was 5.98% and vascular complication 8.96%. CONCLUSIONS: OLT should become a routine therapeutic choice for end-stage liver diseases. Lamivudine is helpful to reduce HBV reinfection after OLT in HBV-related liver diseases. OLT without VVB is safe and can be performed in the majority of adult patients. The early diagnosis and timely application of interventional radiological technique are important for the treatment of biliary and vascular complications.
Adolescent↗
Biologic characteristics of fibroblast cells cultured from the knee ligaments.
OBJECTIVE: To culture fibroblast cells from the knee ligaments and to study the biological characteristics of these cells. METHODS: Cells of the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) from New Zealand white rabbit were cultured in vitro. Cellular growth and expression of the collagen were analyzed. Moreover, an in vitro wound closure model was established and the healing of the ACL and the MCL cells was compared. RESULTS: Maximal growth for all these cells were obtained with Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, but RPMI 1640 and Ham's F12 media were not suitable to maintain these cells. Morphology of both ACL and MCL cells from New Zealand white rabbit was alike in vitro, but the MCL cells grew faster than the ACL cells. Both cell types produced similar amount of collagen in culture, but the ratio of collage type I to type III produced by ACL cells was higher than that produced by MCL cells. Wound closure assay showed that at 36 hours after injury, cell-free zones created in the ACL cultures were occupied partially by the ACL cells; in contrast, the wounded zone in the MCL cultures was almost completely covered by the cells. CONCLUSIONS: Although the ACL cells and the MCL cells from New Zealand white rabbit show similar appearance in morphology in culture, the cellular growth and the biochemical synthesis of collagen as well as the healing in vitro were significantly different. These differences in intrinsic properties of the two types of cells in vitro might contribute to the differential healing potentials of these ligaments in vivo.
Animals↗
Single nucleotide polymorphisms in CAPN10 gene of Chinese people and its correlation with type 2 diabetes mellitus in Han people of northern China.
OBJECTIVE: To investigate the distribution of single nucleotide polymorphisms (SNPs) in CAPN10 gene in Chinese population and their relation with type 2 diabetes mellitus in Han people of Northern China. METHODS: CAPN10 gene was sequenced to detect SNPs in different nationalities of China. Five SNPs were chosen to perform case-control study and haplotype analysis in 156 normal Han people of Northern China and 173 type 2 diabetes. One SNP was also analyzed with transmission-disequilibrium test (TDT) and sib transmission-disequilibrium test (STDT) in 68 type 2 diabetes pedigrees (377 people). RESULTS: A total of 40 SNPs were identified in length of 8,936 bp, with an average of 1 in every 223 bp. The SNPs in CAPN10 gene did not distribute evenly and the SNPs in Chinese were different from those reported in Mexican American. There was no significantly statistical difference in the allele frequency of the 5 SNPs between case and control, and the haplotype frequencies in the two groups were not significantly different. No positive results was found in TDT and STDT analysis. CONCLUSIONS: The SNP distribution of CAPN10 gene differs in different nationalities. The studied SNPs in CAPN10 gene may not be the major susceptibility ones of type 2 diabetes mellitus in Han people of Northern China.
Calpain↗
[Case-control study and transmission/disequilibrium test of childhood absence epilepsy].
OBJECTIVE: To investigate whether or not the gamma-aminobutyric acid (GABA) receptor subtype A genes GABRA5 and GABRB3 are associated with childhood absence epilepsy (CAE). METHODS: Two microsatellite DNA, GABRA5 and GABRB3, adjoining to chromosome 15q11.2-q12 were used as genetic markers. Both case-control study and transmission/disequilibrium test (TDT) as well as fluorescence-based semi-automated genotyping technique were used in 90 trios with CAE and 100 controls to conduct association analysis. RESULTS: The allele frequencies of the 2 microsatellite DNA in Chinese normal population are in good agreement with Hardy-Weinberg equilibrium. The polymorphism information content of microsatellite DNA GABRA5 and GABRB3, are 0.80 and 0.66 respectively. The allele 2 frequency of microsatellite DNA GABRA5 and the allele 5 frequency of microsatellite DNA GABRB3 are significantly higher in CAE patients than those in normal controls(P<0.001). CONCLUSION: Both microsatellite DNA GABRA5 and GABRB3 are good genetic markers. The gamma-aminobutyric acid receptor subtype A genes GABRA5 and GABRB3 may be directly involved either in the etiology of CAE or in linkage disequilibrium with disease-predisposing sites.
Adolescent↗
[Orthotopic liver transplantation with no veno-venous bypass].
OBJECTIVE: To assess the feasibility and outcome of orthotopic liver transplantation (OLT) with no veno-venous bypass (VVB) in adult patients. METHODS: Between 1999 and June 2001, 43 adult patients were subjected to orthotopic liver transplantations with veno-venous bypass (28), or no veno-venous bypass (15). RESULTS: There was no significant difference in mean serum creatinine on day 3 and gas discharge time in patients with veno-venous bypass or not. With no veno-venous bypass, the average operative time was 5.6 +/- 1.4 h, median amount of blood loss during operation was 4 200 +/- 850 ml, median amount of blood transfused intraoperatively was 4 800 +/- 920 ml, and median intensive care unit stay was 6.3 days. All these were lower or shorter than those of the patients with veno-venous bypass. CONCLUSIONS: Orthotopic liver transplantation with no veno-venous bypass is safe and can be performed in the majority of adult patients. Liver transplantation with no veno-venous bypass is associated with shorter total operating time, lower blood product usage, and shorter intensive care unit stay compared with standard technique of OLT with routine use of VVB.
Adult↗
[Mutational analysis of MECP2 gene in Rett syndrome].
OBJECTIVE: To investigate mutations of MECP2 gene in classical sporadic Rett syndrome (RTT) patients in China. METHODS: Polymerase chain reaction, single strand conformation polymorphism, cloning and direct sequencing were employed to analyse the three exons of MECP2 gene in 26 RTT patients and their parents, and in 2 sisters of 2 of the RTT patients. RESULTS: Nine different mutations in exon 3 were identified in 14 of the 26 patients with RTT, including 3 missense mutations, 3 nonsense mutations, and 3 frame-shift mutations (2 deletion mutations and 1 insert mutation); 2 of these were novel. A missense variant was also identified, which was carried by unaffected father and affected daughter. CONCLUSION: Mutations in MECP2 gene were found over 50% of patients with RTT in China.
Base Sequence↗