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Biomedical subjects

Y Cheng

Publications and source records attributed to Y Cheng.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Changes of osteopontin and matrix Gla protein mRNA expressions in the healing process of rat thoracic aorta damaged by balloon angioplasty].

Using Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR) the dynamic changes of osteopontin (OPN) and matrix Gla protein (MGP) mRNA expression in the healing process of rat thoracic aorta damaged by balloon angioplasty were investigated. The results showed that expression of OPN and MGP in the thoracic aorta damaged group was higher compared with normal group. 1, 7, and 14 d after thoracic aorta was damaged, expression of OPN and MGP was increased gradually, and decreased after artery damaged 21 d.

1-Carboxyglutamic Acid↗
PubMed1999

Human DNA oncogenic viruses and their transforming protein interactions with cell cycle control proteins.

PURPOSE: Both oncogenic viruses and cell cycle control proteins are fast-growth research areas. More and more evidence indicates that virus infection and replication are often associated with apoptosis and interfere with cell cycle pathways. To understand the mechanisms by which viral proteins regulate apoptosis and target the cellular pathways may lead to the development of new remedies for some cancers. DATA SOURCES: English literature searched by MEDLINE from January 1995 to August 1998. STUDY SELECTION AND DATA EXTRACTION: More than one hundred research papers published in these areas over the past three years. Only new and important breakthroughs in these papers are selected. The review focuses on DNA viruses associated with the development of human cancers. RESULTS AND CONCLUSIONS: Some DNA viruses contain oncogenic proteins which transform normal cells in vitro and induce tumors in animals. These viral proteins target the cellular pathways and block apoptosis induced by receptors or in response to signal transduction. Viral interference with host cell apoptosis leads to enhanced viral replication and may promote carcinogenesis. Oncogenes and tumor suppressor genes, such as Retinoblastoma (RB) and p53, play important roles in regulation of these interactions.

Animals↗
PubMed1999

[Polymorphisms of apoB gene 3' VNTR alleles and analysis of lipid level in Tibetan population].

OBJECTIVES: To study the distribution and frequency of apoB gene 3' end alleles and try to find if there is any association with the level of plasma lipids. METHODS: PCR and gradient polyacrylamide gel electrophoresis were used to analysize the chromsome DNA and PCR products. RESULTS: Totally 20 alleles were found in the Tibetan group and the distribution of alleles was bimode. The HVE32 and HVE34 were most common, and the frequencies of HVE32 and HVE34 were 0.27 and 0.21 respectively. CONCLUSION: Polymorphism apoB gene resides not only in the variable numbers of the repeat unit, but also in the variation in the oligonucleotide sequence within the repeat units as well as the variation in the arrangement of the repeat units.

Adolescent↗
PubMed1999

[The expression of bombesin receptor in gastric cancer].

OBJECTIVE: To observe the expression of receptor mRNA and its protein in SGC 7901 cells. METHODS: (1) RT-PCR and Southern blot hybridization were performed for detection of gastrin releasing peptide GRP-R mRNA; (2) Covalent cross-linking study with biotinyl-bombesin and enhanced chemoluminescence (ECL) was performed to identify GRP-R at protein levels in SGC 7901 cells. RESULTS: (1) It is shown that the molecular weight of the cDNA was consistent with that of expected. Southern blot was then used to further prove that specific GRP-R mRNA was expressed by SGC 7901. (2) GRP-R protein was shown by covalent cross-linking in SGC 7901 and the molecular weight of bombesin/GRP-R in SGC 7901 cells was about 75000. CONCLUSION: By using RT-PCR, Southern blot and covalent cross-linking techniques, it was demonstrated that SGC 7901 cells can express bombesin receptor mRNA and protein. The results of this study provides a basis for further researches on bombesin intracellular signal transmission pathway and the role of bombesin and bombesin receptor antagonists in oncological research.

Blotting, Southern↗
PubMed1999

[Observations on expression of c-fos and c-myc genes and activity of PDGFBB autocrine loop in 67 human gliomas].

OBJECTIVE: To investigate the variance of expression of c-fos and c-myc genes and the activity of platelet-derived growth factor (PDGF) BB autocrine loop in human gliomas as well as their relationship. METHODS: In situ hybridization and immunohistochemistry were used to study 67 human glioma specimens of different grades. RESULTS: The incidences, of positive expression for c-fos mRNA, c-fos protein, c-myc mRNA and c-myc protein were 100% (67/67), 100% (67/67), 85.1% (57/67) and 83.6% (56/67) respectively. There was significant positive correlation between the positive cell densities of c-fos mRNA (92.49 +/- 33.87) and c-fos protein (91.64 +/- 38.11), and of c-myc mRNA (72.70 +/- 40.56) and c-myc protein (71.49 +/- 41.11, r = 0.917 - 0.988, P < 0.001). All of them also increased correspondingly with the malignant degree of the tumors and level of PDGFB mRNA expression in the tumor cells (P < 0.05 - 0.01). Not only were the positive cell densities of PDGF alpha receptor (58.46 +/- 28.77), PDGF beta receptor (63.03 +/- 31.63) and phosphotyrosine protein (68.25 +/- 29.30) correlated positively with one another (r = 0.827 - 0.896, P < 0.001), but they also all correlated positively with the positive cell densities of PDGFB mRNA, c-fos mRNA, c-fos protein, c-myc mRNA and c-myc protein respectively (r = 0.615 - 0.888, P < 0.001). CONCLUSIONS: The abnormally increased activity of the PDGFBB autocrine loop possibly upregulated the overexpression of c-fos and c-myc genes in glioma cells and suggested that c-fos and c-myc proteins probably played an important role as downstream response factors in the signaling pathway in which PDGFBB could induce gliocyte transformation and glioma development.

Adolescent↗
PubMed1999

[Effect of diazepam on fetus after intravenous administration during the active phase in labour].

To investigate the effects of diazepam on fetal heart rate and Apgar scoring administered intravenously during the active phase in labour, sixty-two normal term parturients during the active phase of labour with the cervical dilation to 3-5 cm were randomly divided into two groups, diazepam group (n = 32) and control group (n = 30). In diazepam group, 10 mg diazepam was administered intravenously. The concentrations of diazepam in maternal and cord serum were measured by high performance liquid chromatography after birth and the fetal heart rates were monitored by electronic monitor before or after administration of diazepam and Apgar scores were determined immediately after birth. The results showed that the mean level of diazepam in umbilical cord serum was markedly higher than that of maternal serum. Fetal heart base line mutation in diazepam group was weaker than that of the control group. Apgar scores in the neonates of diazepam group was lower than those of the control group. The results indicate that the use of diazepam in pregnant women during active phase of labour may cause depression of fetus.

Adult↗
PubMed1999

[Quantitative determination of vanillic acid in rhizoma Picrorhizae by TLC-scanning].

OBJECTIVE: To establish a method to determine the content of vanillic acid in Rhizoma Picrorhizae. METHOD: The content was determined by dual wavelength TLC-scanning. RESULT: The peak area of vanillic acid is reproducible in 4 hours; recovery 96.5%; RSD-3%; RSD of duplicate experiment-5%. CONCLUSION: A thin-layer chromatographic scanning method has been developed for determining the content of vanillic acid. The method is reproducible, workable and reliable.

Chromatography, Thin Layer↗
PubMed1999

[Cloning and sequence characterization of heavy chain variable region gene from hybridoma cells secreting MAB against VEGF].

OBJECTIVE: To clone the variable region of heavy chain (VH) gene from hybridoma secreting monoclonal antibody against human vasoendothelial growth factor (VEGF) for construction of recombinant antibody (scFv). METHODS: One step method was used to extract total RNA and degeneration primer was used to amplify the cDNAs by retropolymerase chain reaction (RT-PCR), then the products were inserted to T-vector and its sequence was analysed. RESULTS: The VH gene contained 369 base pairs encoding 123 amine acid resides. Analysis of the nucleotide sequence of the light chain variable region revealed that the VH sequence was 87% identical to the sequence present in mouse Ig VH region. CONCLUSION: The VH gene was 369 bp. According to Kabat classification, the VH gene belonging to mouse kappa light chains subgroup I (A), resulting from VH-D-JH4 rearrangment.

Amino Acid Sequence↗
PubMed1999

[Isotachophoresis analysis of hydrolytic products of DFP catalyzed by DFPase in porcine liver].

DFPase can hydrolyze the P-F bond of diisopropyl phosphate fluoride (DFP) to produce diisopropyl phosphate and HF. In this article, the activity of two kinds of DFPase from porcine liver was assayed by the methods of titration and F- ion sensitive electrode. The results showed that the activity of large molecular DFPase can be determined by both methods, but the activity of small molecular DFPase can only be determined by the titration and cannot be determined by F- ion sensitive electrode. The isotachophoresis analysis of the products of DFP hydrolyzed by the large and small molecular DFPase was studied. The results showed that the small molecular enzyme could catalyze the hydrolysis of DFP, but without the production of F- ion, and that this enzyme is one kind of phosphoesterase that hydrolyzed P-OR bond of DFP.

Animals↗
PubMed1999

[Studies on the relationship between the infection of intermediate hosts of Paragonimus and ecological environment].

AIM: To explore the relationship between the infection of the intermediate hosts of Paragonimus and their ecological environment. METHODS: Three different villages in Fujian Province were chosen to conduct the study. The infection of snails and crabs were surveyed. RESULTS: 1. In Ningyang Village, Wuyi mountain(stream type), the infection rate of the Potamon crabs (723.9/each) in section I (rapid stream) was 5 times higher than that in section II (rapid stream) 142.6/each. 2. In Xikou Village, Mingching county(ditch type): The infection rate of the snails (Semisulcospira libertina) to cercaria and the Potamon crabs were 4.2% and 1,738.3/each, respectively in 1996, being 28.9 and 8.5 times higher than those (0.2% and 204.7/each) in 1982. 3. In Jishang Village, Jianou City, the infection rate of the snails (Tricula) and the Potamon crabs were 4.3% and 355.4/each respectively in ditch III, 4.3 and 8.3 times higher than those (1% and 42.9%/each) in ditch II. CONCLUSION: P. westermani distributed along the stream system, usually concentrating in the small, slow-running water bodies of the stream. P. skrjabini distributed in still smaller water bodies. The environment suitable for the breedings of the snails and crabs are also the suitable places for Paragonimus parasites to complete their life cycles.

Animals↗
PubMed1999

[Taxonomic studies on Echinochasmus fujienensis and its related species by random amplified polymorphic DNA analysis and experimental infection].

AIM: To explore the identification and differentiation of Echinochasmus fujianensis, Echinochasmus japonicus(Jiangxi strain and Fujian strain), Echinochasmus liliputanus Anhui and Echinochasmus per foliatus Hubei. METHODS: Random amplified polymorphic DNA analysis (RAPD) and experimental animal infection were performed. RESULTS: 469 polymorphic DNA fragments were obtained by 28 primers from 4 Echinochasmus species and strains in Fujian, Anhui and Jiangxi. 20.8% and 97.6% of the fragments in Echinochasmus fujianensis were the same as those in Echinochasmus japonicus Fujian strain and in Echinochasmus liliputanus Anhui, respectively, 99.7% of the fragments were the same between Echinochasmus japonicus Jiangxi strain and Fujian strain. CONCLUSION: Echinochasmus fujianensis and Echinochasmus liliputanus Anhui are the same species. Echinochasmus fujienensis is an independent species different from Echinochasmus japonicus. Polyinfection of Echinochasmus fujianensis, Echinochasmus japonicus and Echinochasmus perfoliatus exist in all the 3 provinces, Hubei, Anbui and Fujian, of which Echinochasmus fujienensis is a dominant species.

Animals↗
PubMed1999

[Preliminary study on NS5 region gene sequencing and variants of hepatitis G virus in China].

OBJECTIVE: To study the genomic specificity and variation of Hepatitis G virus(HGV) in China. METHODS: The 141nt cDNA fragments locating at nonstructural region 5 (NS5) of HGV were obtained from the sera of 16 HGV infected patients by RT-nested-PCR using NS5 primers, then purified and directly sequenced by dideoxynucleotide chain termination method. RESULTS: The sequence diversity near the N-terminus of the region between nt 7,820 and 7,960 was more marked than that near the C-terminus. Compared with the HGV-US isolate, the nt alterations of NS5 in Chinese isolates usually took place at nt 7,824, 7,892, 7,914, 7,917, 7,935 and in region nt 7,845-7,860, the rate of variability at one nt position was 0-89.5%. The nucleotide homology was 83.6%-95.7% (89.6% in average) and the homology of deduced amino acid sequence was 83.0-100%(91.2% in average). CONCLUSION: The nucleotide and deduced amino acid sequences of NS5 of Chinese HGV are relatively conserved but are obviously different from the HGV and GBV-C reported in USA in this study.

Adult↗
PubMed1999

[Analysis of genome character and amino acid residues 2,209 to 2,248 of NS5 A region of hepatitis C virus in relation to the response to interferon therapy].

OBJECTIVE: To observe nucleotide sequence variations and amino acid residues 2,209 to 2,248 of the NS5 A region of hepatitis C virus in relation to interferon therapy in Chinese patients infected with HCV genotype 1b. METHODS: We collected sera from 22 patients infected with HCV genotype 1b, performed nested RT-PCR using extracted serum RNA from sera, amplified NS5 A region 2,209 to 2,248 and sequenced the PCR product directly. The deduced amino acid sequences were compared with the corresponding region of the HCV-J prototype strain. RESULTS: Only 4 isolates were intermediate type, and no mutant type was found. In 18 patients treated with IFN-alpha, only 4 were HCV RNA negative at present, No correlation was found between amino acid mutation and IFN response. CONCLUSION: Variations in the NS5 A region between amino acid residues 2,209 to 2,248 failed to predict IFN response in Chinese patients infected with HCV genotype 1b. IFN may accelerate nucleotide variation but has little influence on amino acid variations.

Antiviral Agents↗
PubMed1999

Diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroendoscopic biopsy specimens.

UNLABELLED: We evaluated the diagnostic criteria of gastric lymphoma in endoscopic biopsies. METHODS: Our study included cases diagnosed as lymphoma by gastroendoscopic biopsy between 1984 and 1994 that were available in the files of the Department of Gastroenterology, Chinese PLA General Hospital. RESULTS: Among 53,400 cases of gastroendoscopy, we found 1672 (3%) cases of malignant neoplasm that were diagnosed by endoscopic features and histological findings. Thirty-eight cases of primary gastric lymphoma included 22 men and 16 women 16 to 82 years old, with a median age of 47.7. The endoscopy showed the ulcerative type in 12 cases, diffuse infiltrating type in 11 cases, massive infiltrating type in 6 cases, and large mucosal folds type in 4 cases. Five cases had a mixed type pattern of involvement. Histologically, 34 cases showed mucosa-associated lymphoid tissue lymphoma (89.5%), 2 cases had lymphoblastic lymphoma, and 2 cases were unclassifiable because of crush artifact of neoplastic cells. The majority of cases of primary gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa-associated lymphoid tissue (MALT).

Adolescent↗
PubMed1998

Molecular cloning and characterization of a novel retinoic acid-inducible gene that encodes a putative G protein-coupled receptor.

The effects of retinoids such as all-trans-retinoic acid (ATRA) on cell growth, differentiation, and apoptosis are thought to be mediated by nuclear retinoid receptors, which are involved in ligand-dependent transcriptional activation of target genes. Using differential display, we identified the cDNA of a novel gene, designated retinoic acid-inducible gene 1 (RAIG1), which was induced by ATRA in the squamous carcinoma cell line UMSCC-22B. Two RAIG1 transcripts of 2.4 and 6.8 kilobase pairs, respectively, have the same ORF that encodes a 357-amino acid polypeptide. RAIG1 mRNA is expressed at high level in fetal and adult lung tissues. Induction of RAIG1 expression by ATRA is rapid (within 2 h) and dose-dependent in the range between 1 nM to 1 microM. The constitutive RAIG1 mRNA levels, which were low in three of five head and neck and four of six lung cancer cell lines, increased after ATRA treatment in most cell lines. The deduced RAIG1 protein sequence contains seven transmembrane domains, characteristic of G protein-coupled receptors. A fusion protein of RAIG1 and the green fluorescent protein was localized in the cell surface membrane and perinuclear vesicles in transiently transfected cells. RAIG1 was mapped to chromosome 12p12. 3-p13. Our results provide novel evidence for a possible interaction between retinoid and G protein signaling pathways.

Amino Acid Sequence↗
PubMed1998

p53 inactivating mutations in Chinese nasopharyngeal carcinomas.

Previously a low frequency of p53 mutations was detected in nasopharyngeal carcinoma (NPC) using molecular techniques to screen for mutations, yet immunohistochemical staining revealed a high frequency of p53 aberrant proteins. These findings might be attributed to the occurrence of p53 mutations outside the common hot spots and/or the inactivation of the protein through interactions with cellular or viral proteins. Using a previously established simple and sensitive p53 yeast functional assay, we blindly screened 25 nasopharyngeal biopsies for p53 mutations from exons 4 to 11. p53 was mutated in 27.3% of NPC specimens and in 0% of the nasopharyngeal biopsies from patients with non-malignant diseases. Two p53 mutations were detected in exon 7 and two were detected in exon 8. Interestingly, the exon 8 mutations observed in NPC lie in codons which appear to be hot spots for mutations in other head and neck cancers.

Adolescent↗