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Biomedical subjects

Jun Cheng

Publications and source records attributed to Jun Cheng.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Study of serum Hcy and polymorphisms of Hcy metabolic enzymes in 192 families affected by congenital heart disease].

OBJECTIVE: To explore genotype distributions at MTHFR C677T, MS A2756G, MTHFD G1958A and CBS 844 ins68bp loci in healthy Chinese living in northern area, and to assess the association of single or combined gene mutations with folic acid, Vit.B(12), Hcy levels and CHD. METHODS: 192 patients having CHD and their biological parents in Liaoning province registered as birth defects were included in this study as case group, and 124 healthy subjects (age and gender matched) and their biological parents were simultaneously selected from the same geographic area as control. To all subjects, the gene polymorphism at MTHFR C677T, MS A2756G, MTHFD G1958A and CBS 844 ins68bp loci was examined with PCR-RFLP. The serum folic acid and homocysteine (Hcy) level were analyzed with Radioimmunoassay or fluorescence polarization immunoassay (FPIA). RESULTS: In healthy Chinese living in northern China, the mutant allele frequencies of these four loci were MTHFR 51.18%, MS 7.58%, MTHFD 24.32%, and CBS insertion 2.36%, respectively. The heterozygosity of CBS 844 ins68bp was more prevalent in case than in control (12.57% vs 2.97% in children, 10.88% vs 3.09% in father and 11.54% vs 1.02% in mother, respectively), and yielded an odds ratio (OR) of 4.70 (95% CI 1.34-25.15) in children, 3.83 (95% CI 1.05-20.98) in fathers and 12.65 (95% CI 1.92-532.47) in mothers. There is no existed significant difference at the other three loci. The percents of mothers with MTHFR, CBS and MTHFD gene polymorphisms, of mothers with MTHFR and CBS being polymorphisms (OR=8.44, 95aCI 1.23-362.26), of mothers with MTHFD and CBS being polymorphisms in case were higher than those in control. Serum folic acid levels of mothers and fathers in case were significantly higher than those of counterparts in control. Serum Hcy level of mothers in case was higher than that of counterparts in control without significant difference. Homozygous mutation at MTHFR and MTHFD loci made serum folic acid and Vit.B(12) levels slightly decreased and serum Hcy level increased. CONCLUSION: The study showed presence of ethnic and district difference of gene polymorphisms at these four loci. 68 bp insertion at exon 8 of CBS gene base 844 could be a risk factor for CHD, and the insertion in parents (especially in mothers) could increase CHD risk in offspring.

Female↗
PubMed2005

The effect of fructose-1, 6-diphosphate and HTK solution on protecting primary cardiac muscle cells of rat with cold preservation.

In this study we tried to investigate the effect of fructose-1,6-diphosphate and HTK solution on protecting primary cardiac muscle cells of rat with cold preservation. The primary cardiac muscle cells of rat were cultured in vitro with four preservation solutions respectively: 0.9% sodium chloride solution (group A), FDP (group B), HTK solution (group C) and a mixture of FDP and HTK solution (group D). The cells were preserved for 6, 8 and 10 h at 0-4 degrees C. The values of AST and LDH-L and the Na+-K+ ATPase activity in cardiac muscle cells were detected, and the survival rate of cardiac muscle cells was detected with trypan blue staining. The values of AST and LDH-L in group C and group D were remarkable lower those in group A and group B (P<0.001), while the Na+-K+ ATPase activity and the survival rate of cells in group C and group D were much higher than those in group A and group B (P<0.001). The values of AST and LDH-L after 6 hours in group D decreased much more than those in group C (P<0.01), while the Na+-K4 ATPase activity and the survival rate of cells in group D improved more than those in group C (P<0. 01). Both of the HTK solution and the mixture of HTK and FDP solution have an evident effect on protecting the primary cardiac muscle cells of rat in vitro with cold preservation, Compared with the HTK solution, the mixture solution has a better short-term protective effect.

Animals↗
PubMed2005

Nucleotide sequences and functions of the Epstein-Barr virus latent membrane protein 1 genes isolated from salivary gland lymphoepithelial carcinomas.

Epstein-Barr virus (EBV) infection is associated with salivary gland lymphoepithelial carcinoma (SLEC) and nasopharyngeal carcinoma (NPC). EBV is a ubiquitous herpes virus world wide, but EBV-associated SLEC and NPC are prevalent in restricted regions such as south areas of China, Southeastern Asia and Greenland (Eskimos). To examine whether particular EBV variants play roles in the development of SLEC and NPC, we isolated the complete EBV LMP1 genes from 12 paraffin-embedded biopsy samples of SLECs isolated from China, Taiwan and Russia, and compared these LMP1 genes with those of NPC (CAO) and the prototype B95-8 EBV. Nucleotide sequence analysis showed that SLECs LMP1 is more similar to that of CAO than that of prototype B95-8. The analysis also identified several conserved (67-100%) variations in SLEC-LMP1 and CAO-LMP1 distinct from B95-8-LMP1. These included 10-amino acid deletion, 5-amino acid deletion and 12-single amino acid variations. A SLEC-LMP1 gene with the aforementioned conserved variations inhibited the growth of an embryonic kidney cell line (293T), highly activated the NF-kappaB pathway, and these activities were equivalent to those of B95-8 and CAO. These findings suggest that the biological functions of SLEC-LMP 1 are similar to those of B95-8-LMP1 and CAO-LMP1, and that these amino acid variations including the well-known 10-aa deletion did not affect these two prominent activities. While the present results could not uncover functional differences between SLEC-LMP1 and B95-8-LMP1, the nucleotide sequences and the molecular clone of LMP1 directly isolated from SLEC patients will be a useful tool to identify the high-pathogenic EBV strain(s), associated with SLEC and NPC.

Amino Acid Sequence↗
PubMed2005

Establishment and characterization of new cell lines derived from melanotic neuroectodermal tumor of infancy arising in the mandible.

Three cell systems (MINT1/2/3) derived from a melanotic neuroectodermal tumor of infancy (MNTI) arising in the mandible of a 1-month-old newborn boy have been established, and their cytological natures have been characterized. The cells had immunopositivities for pan-keratin, vimentin, neuron-specific enolase, S-100 protein and melanoma-associated antigen (HMB-45). These immunohistochemical phenotypes were basically the same as those observed in tissue sections, in which, synaptophysin, myelin basic protein, c-myc gene products, carcinoembryonic antigen, and epithelial membrane antigen were also immunolocalized in tumor cells. Karyotyping analyzes revealed that the chromosome numbers of the three cell systems ranged from 60 to 67 with 3n ploidies, and that there were many structural aberrations, such as del(11)(q13), del(22)(q13), add(2)(p11), add(7)(q22), extra copies for chromosomes 1, 2, 3, 5, 7, 9, 10, 11, 12, 16, 20, and 22, der(9)t(9;13)(p13;q12)add(9)(q34), and der(13;21)(q10;q10), which were shared by the three cell systems, while der(19)t(11;19)(q13;p13) was found in MINT1 and MINT3. When stimulated by endothelin-3 and vitamin D(3), the cells had spinous cell shapes with immunopositivities for HMB-45, neurofilament protein and glial fibrillary acidic protein, which indicated more neural differentiation. The established cell systems will be useful for further investigation on the molecular and genetic basis of MNTI to understand its pathogenesis, which is largely unknown.

Animals↗
PubMed2005

Two-phase appearance of oral epithelial dysplasia resulting from focal proliferation of parabasal cells and apoptosis of prickle cells.

BACKGROUND: One of the histologic characteristics of epithelial dysplasias of the oral mucosa is droplet-shaped rete processes resulting from a solid proliferation of basaloid cells. These basaloid cells are suddenly changed into an overlay of parakeratotic cells. However, it is unknown how this characteristic two-phase appearance is generated. METHODS: Formalin-fixed paraffin sections of the oral mucosal specimens with normal, hyperplastic, dysplastic epithelia and squamous cell carcinomas were examined for apoptosis by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) method and for lymphoid cells by immunohistochemistry. RESULTS: Apoptotic cells were only located in the keratinized layer of normal/hyperplastic epithelia. However, in epithelial dysplasias, apoptotic cells were scattered in the middle or even in the lower parts of the epithelial layer with frequent vacuolation changes of epithelial cells. Within the epithelial layer of dysplasias, there were increased number of lymphocytes, which were immunopositive for CD45RO, CD8, and CD57- and CD68-immunopositive (+), S-100 protein-positive and major histocompatibility complex (MHC) class II-positive monocytic lineages. They increased in number with the severity of dysplastic degrees, and they were often located in the vicinity of apoptotic epithelial cells, but decreased in carcinomas in situ and invasive carcinomas, which contained fewer numbers of apoptotic figures. CONCLUSION: The findings indicate that intraepithelial infiltrations of both cytotoxic T cells and natural killer cells are closely related to the apoptotic phenomena of prickle cells, which may result in the characteristic 'two-phase appearance' of epithelial dysplasia.

Apoptosis↗
PubMed2005

Extracellular matrix remodeling in oral submucous fibrosis: its stage-specific modes revealed by immunohistochemistry and in situ hybridization.

BACKGROUND: Oral submucous fibrosis (OSF) is a chewing habit-related pre-cancerous condition of the oral mucosa affecting predominantly south Asians. It is histopathologically characterized by epithelial atrophy and fibrosis of the subepithelial connective tissue. Fibrosis extends all the way into the muscle layer, leading to difficulty in mouth opening. However, the dynamics of extracellular matrix (ECM) remodeling with OSF progression is largely unknown. METHODS: Forty biopsy specimens of OSF and 10 of normal buccal mucosa were examined for expression/deposition modes of eight ECM molecules by histochemistry, immunohistochemistry, and in situ hybridization. RESULTS: In the early stage of OSF, tenascin, perlecan, fibronectin, collagen type III were characteristically enhanced in the lamina propria and the submucosal layer. In the intermediate stage, the ECM molecules mentioned above and elastin were extensively and irregularly deposited around muscle fibers. In the advanced stage, such ECM depositions decreased and were entirely replaced with collagen type I only. Their gene expression levels varied with progression of fibrosis, but the mRNA signals were confirmed in fibroblasts in the submucosal fibrotic areas. CONCLUSIONS: The results indicate that the ECM remodeling steps in OSF are similar to each phase of usual granulation tissue formation. Restricted mouth opening may be a result of loss of variety of ECM molecules including elastin into the homogeneity of collagen type I replacing muscle fibers.

Case-Control Studies↗
PubMed2005

Flavonoids from Millettia nitida var. hirsutissima.

From the stems of Millettia nitida var. hirsutissima, three new isoflavone glycosides, formononetin 7-O-beta-D-(6''-ethylmalonyl)-glucopyranoside (1, hirsutissimiside A), 5-O-methyl genistein 7-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (3, hirsutissimiside B), retusin 7,8-di-O-beta-D-glucopyranoside (4, hirsutissimiside C) and two known isoflavone glycosides (2) and (5) have been isolated. The structures of the compounds were determined by spectroscopic and chemical means.

Carbohydrate Conformation↗
PubMed2005

Statistical properties of nucleotide clusters in DNA sequences.

Using the complete genome of Plasmodium falciparum 3D7 which has 14 chromosomes as an example, we have examined the distribution functions for the amount of C or G and A or T consecutively and non-overlapping blocks of m bases in this system. The function P(S) about the number of the consecutive C-G or A-T content cluster conforms to the relation P(S) proportional, variante(-alphas); values of the scaling exponent alpha(CG) are much larger than alpha(AT); and alpha(AT) of 14 chromosomes are hardly changed, whereas alpha(CG) of 14 chromosomes have a number of fluctuations. We found maximum value of A-T cluster size is much larger than C-G, which implies the existence of large A-T cluster. Our study of the width function xi(m) of cluster C-G content showed that follows good power law xi(m) proportional, variantm(-gamma). The average gamma for 14 chromosomes is 0.931. These investigations provide some insight into the nucleotide clusters of DNA sequences, and help us understand other properties of DNA sequences.

Animals↗
PubMed2005

[Identification and analysis of a mouse gene homologous to human hepatitis B virus pre-S1 protein-binding protein using the bioinformatics method].

OBJECTIVE: To clone and identify the mouse gene homologous to human hepatitis B virus (HBV) pre-S1 protein-binding protein (PS1BP). METHODS: The human PS1BP cDNA sequence was used as the reference sequence to search homologous mouse cDNA sequence from GenBank established by National Center for Biotechnology (NCBI), National Institute of Health (NIH), for its homologous cDNA sequences of mouse by BLASTn tool. The characteristics of mouse PS1BP protein primary structure were predicted by online software. Finally the genomic DNA structure of mouse PS1BP was deduced and compared. RESULTS: The mouse PS1BP was identified and consisted of 1455 nt, coding a protein of 484 aa. The identity of human and mouse PS1BP protein is 84.92% (411/484). The genomic DNA of mouse PS1BP consisted of 3 exons and 2 introns. CONCLUSION: The identification and characterization of mouse PS1BP cDNA and genomic DNA pave a way for further study of their structures and functions.

Amino Acid Sequence↗
PubMed2005

[Screening of HBeAgTP interacting proteins in hepatocytes with yeast-two hybrid technique].

OBJECTIVE: To screen proteins in hepatocytes interacting with HBeAg transactivated protein (HBeAgTP) with yeast-two hybrid technique for investigating the biological functions of HBeAgTP. METHODS: Suppression subtractive hybridization (SSH) and bioinformatics techniques were used for screening and cloning of the target genes transactivated by HBeAg. The HBeAgTP gene was amplified by polymerase chain reaction (PCR) and HBeAgTP bait plasmid was constructed with yeast-two hybrid system 3, and then transformed into yeast AH109. The transformed yeast mated with yeast Y187 containing liver cDNA library plasmid in 2 x YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-gal for selecting two times and screening. After extracting and sequencing of plasmid from blue colonies, the results were analyzed by bioinformatics. RESULTS: HBeAgTP gene was successfully cloned and expressed in yeast cells. Fifteen genes in twenty-four positive colonies were obtained using yeast-two hybrid technique. CONCLUSION: HBeAgTP conjugated protein genes were successfully cloned, along with the genes involved in transcription and translation of proteins, immunoloregulation, materials and energy metabolism in vivo.

Hepatitis B e Antigens↗
PubMed2005

Relationship between polymorphism of methylenetetrahydrofolate dehydrogenase and congenital heart defect.

OBJECTIVE: To investigate the relationship between G1958A gene polymorphism of methylenetetrahydrofolate dehydrogenase (MTHFD) and occurrence of congenital heart disease (CHD) in North China. METHODS: One hundred and ninety-two CHD patients and their parents were included in this study as case group in Liaoning Province by birth defect registration cards, and 124 healthy subjects (age and gender matched) and their parents were simultaneously selected from the same geographic area as control. Their gene polymorphism of MTHFD G1958A locus was examined with PCR-RFLP, and serum folic acid and homocysteine (Hcy) levels were tested with radio-immunoassay and fluorescence polarization immunoassay (FPIA). RESULTS: There existed gene polymorphism at MTHFD G1958A locus in healthy subjects living in North China. The percentages of GG, GA, and AA genotype were 57.98%, 35.57%, and 6.45% respectively, and the A allele frequency was 24.23%, which was significantly different from Western population. No difference was observed when comparing genotype distribution and allele frequency between the case and control groups, so was the result from the comparison between genders. The A allele frequency of arterial septal defect patients' mothers (10.87%) was significantly lower than that of controls (28.15%) (P=0.014), with OR=0.31 (95% CI: 0.09-0.84), and no difference in the other subgroups. The percentage of at least one parent carrying A allele in arterial septal defect subgroup (43.48%) was significantly lower than that in controls (69.64%) (P=0.017), with OR=0.34 (95% CI: 0.12-0.92). The analysis of genetic transmission indicated that there was no transmission disequillibrium in CHD nuclear families. Their serum folic acid level was significantly higher than that of controls (P=0.000), and Hcy level of the former was higher than that of the latter with no statistical significance (P>0.05). Serum Hcy and folic acid levels of mothers with gene mutation were lower than those of mothers with no mutation. CONCLUSION: No significant difference of genotype distribution and allele frequency existed between CHD patients and healthy population. MTHFD G1958A mutation in parents (particularly in mother) can decrease the risk of arterial septal defect in offspring. The possible mechanism of protection might be mutation, which can increase MTHFD enzyme activity, folic acid metabolism and homocysteine remethylation, and decrease Hcy level.

Adolescent↗
PubMed2005

[Screening of binding proteins to interferon-alpha promoter DNA by phage display technique].

OBJECTIVE: To investigate the interferon alpha regulation mechanisms by screening binding proteins of interferon alpha promoter by phage display. METHODS: PCR product of interferon-alpha promoter was incubated with a phage display cDNA library that expressed a library of human liver proteins on the surface of bacteriophage T7. Unbound phages were washed off and the phages bound to the interferon alpha promoter were amplified. Positive plaques were amplified by PCR and cloned into a pGEM-Teasy vector in order to perform DNA sequence analysis and subsequent computer blasting analysis. RESULTS: Positive phage-displayed proteins binding with interferon alpha promoter were enriched after five rounds of biopanning. We found that the following proteins were relevant to interferon alpha: mitochondrial ribosomal protein, chromosome clone, fibrinogen A alpha polypeptide, enoyl coenzyme A hydratase short chain, eukaryotic translation elongation factor 1 alpha, PI-3-kinase-related kinase SMG-1-like, xeroderma pigmentosum C group, and Homo sapien activity-dependent neuroprotector (ADNP). CONCLUSION: Many proteins with different functions could bind with interferon alpha promoter.

DNA, Complementary↗
PubMed2005

[Study of the down-regulating effect of hepatitis C virus NS5A protein on NACA promoter].

OBJECTIVE: To investigate the effect of hepatitis C virus (HCV) non-structure protein NS5A on the activity of calcium-regulating protein alpha subunit of nascent polypeptide-associated complex (NACA) promoter. METHODS: HepG2 cell plasmid pCAT3-NACA, containing NACA promoter, was transfected alone or cotransfected with pcDNA3.1(-)-NS5A, and chloramphenicol acetyl transferase (CAT) enzyme activity was assayed by enzyme-linked immunoassay (ELISA). RESULTS: The CAT activity in the pcDNA3.1(-)-NS5A cotransfection group was 20.7% of the CAT activity in the pCAT3-NACA group. CONCLUSION: HCV non-structural protein NS5A has a down-regulating effect on the promoter of NACA gene.

Base Sequence↗
PubMed2005

[Screening and cloning target genes transactivated by hepatitis C virus F protein using suppression subtractive hybridization technique].

OBJECTIVES: To identify and clone human genes transactivated by HCV F protein by constructing a cDNA subtractive library using the suppression subtractive hybridization technique. METHODS: Suppression subtractive hybridization (SSH) and bioinformatics techniques were used for screening and cloning of the target genes transactivated by HCV F protein. The mRNA was isolated from HepG2 cells transfected with pcDNA3.1 (-)-F or with pcDNA3.1(-) empty vector as a control, and SSH method was employed to analyze the differentially expressed DNA sequence between the two groups. After restriction enzyme Rsa I digestion, small sized cDNAs were obtained. Then tester cDNA was divided into two groups and ligated to the specific adaptor 1 or adaptor 2. After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR, it was then subcloned into T/A plasmid vectors to set up the subtractive library. Amplification of the library was carried out with E. coli strain DH5 alpha. The cDNA was sequenced and analyzed in GenBank with blast search after PCR. RESULTS: The subtractive library of genes transactivated by HCV F protein was constructed successfully. The amplified library contains 71 positive clones. Colony PCR shows that 56 clones contain 200-1000 bp inserts. Sequence analysis was performed on 28 clones randomly, and the full length sequences were obtained with using the bioinformatics method. Altogether 19 coding sequences were obtained, consisting of 17 known and 2 unknown. CONCLUSIONS: The obtained sequences may be target genes transactivated by HCV F protein, and some gene coding proteins are those involved in cell cycle regulation, metabolism, and cell apoptosis.

Cloning, Molecular↗
PubMed2005

[Association of mutations of HFE gene and hepatocellular carcinoma following chronic hepatitis B].

OBJECTIVE: To investigate the frequency of HFE gene variants in patients with hepatocellular carcinoma following chronic hepatitis B and to analyze their relationships. METHODS: 56 patients with hepatocellular carcinoma following chronic hepatitis B (HCC group) and 60 healthy blood donors (control group) were studied for the amino acid dimorphism at codon 63 (His63Asp=H63D) and codon 282 (Cys282Tyr = C282Y) of the HFE gene. The codon 63 and 282 dimorphisms were defined by PCR amplification of genomic DNA samples and restriction enzyme digestion using RsaI for C282Y and BclI for H63D. The association between hepatocellular carcinoma following chronic hepatitis B and HFE mutations were analyzed by Chi-square test. RESULTS: The genotype frequency of C2/C2 in the HCC group was markedly higher than that in the normal control group (10.7% vs 0) and there was a significant correlation between them. At the same time, the allele frequency of C2 in the HCC group was markedly higher than that in the normal control group (16.1% vs 1.7%) and there was a significant correlation between them also. CONCLUSION: The mutation of C282Y may be related with susceptibility to HCC after chronic hepatitis B. This outcome suggests that host HFE mutation may be an important factor related to the pathogenesis of HCC.

Adult↗
PubMed2005

[Screening and cloning of the genes of protein interacting with the N-terminal protein of hepatitis B virus DNA polymerase by yeast-two hybrid technique].

OBJECTIVE: To screen and clone the genes of protein interacting with the N-terminal protein (TP) of hepatitis B virus DNA polymerase. METHODS: TP was amplified by polymerase chain reaction (PCR) and TP bait plasmid was constructed by using yeast two-hybrid system 3, then transformed into yeast AH 109. The transformed yeast was mated with yeast Y187 containing liver cDNA library plasmid in 2 x YPDA medium. Diploid yeast was plated on synthetic dropout medium (SD/-Trp-Leu-His-Ade) and that containing X-alpha-GAL for selecting two times and screening. Plasmids were extracted from blue colonies, and sequence analysis was performed by bioinformatics. RESULTS: Forty-seven clones were obtained, these clones included human P36956 sterol regulatory element binding protein-1, RNA polymerase II subunit hsRPB7 mRNA, asialoglycoprotein receptor 2, transcript variant 3, ceruloplasmin (ferroxidase), transmembrane 4 superfamily member 2 and 19 of the hypothetical proteins and so on. CONCLUSION: Genes encoding TP interacting proteins in hepatocytes were successfully cloned and the results suggest that TP has a wide variety of biological functions.

Cloning, Molecular↗