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Biomedical subjects

Y Cheng

Publications and source records attributed to Y Cheng.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Sequence diversity of genotype II/1b hepatitis C virus (HCV) HVR1 of 46 patients in Beijing areas].

OBJECTIVE: To study the sequence diversity of the hypervariable region 1(HVR1) in the putative envelope protein E2/NS1 of HCV in Beijing and its neighbouring regions. METHODS: The cDNAs (nt1119-1258) derived from plasma of 46 patients infected with genotype II/1b HCV were amplified, purified and directly sequenced by using RT-nested polymerase chain reaction(PCR) and dideoxynucleotide chain termination method. RESULTS: The HVR1 was found in aa384-408 positions of E2 protein, which had some differences with other report. Compared with HCV-J, HCV-TW, HCV-HB and HCV-HB11, the nucleotide sequence homological rates of these HVR1 were 44.0%-66.7%(57.7%), 48.0%-72.0%(60.0%), 60.0%-85.3%(69.8%), and 56.0%-81.3%(68.2%) respectively, and the amino acid sequence homological rates were 20.0%-56.0%(38.2%), 32.0%-64.0%(45.7%), 36.0%-76.0%(49.8%) and 40.0%-76.0%(55.6%) respectively. There were 6 conserved amino acids in HVR1: AA385(Thr), AA389, 390, 406(Gly), AA401(Ser) and AA403(Phe). Two highly conserved amino acids were only found in this paper. CONCLUSION: The further study of the diversity of HVR1 and its biological significance will be beneficial to the development of HCV vaccine.

Adolescent↗
PubMed1999

[Zeng-Ding phenomenon: further demonstration and studies on its predictive value in epidemic of measles and scarlet fever].

OBJECTIVE: To demonstrate further the existence of Zeng-Ding phenomenon in disease epidemic and to explore the relationship between it and the time series in different kinds of diseases. METHODS: Incidence data of notifiable communicable diseases during 1975 to 1996 were collected. Time series of measles and scarlet fever incidence during 1975 to 1995, 1980 to 1995, 1985 to 1995 and 1990 to 1995 were established. Correlation analysis was conducted between monthly cumulative percentage and predictive ratio of increase to decrease in incidence rate at the best cut-off point. Prediction was studied based on the constructed extrapolation model. RESULTS: Correlation analysis showed that 98.3% (232/236) of the coefficients of correlation were negative (R < 0), indicating further the existence of Zeng-Ding phenomenon in disease epidemic. There was significant difference in coefficients of correlation between the four time series, which accounted for 63.8%, 54.2%, 44.1% and 35.0%, respectively; and for 73.3%, 56.7%, 36.7% and 36.7%, respectively, in measles, and for 53.6%, 51.8%, 51.7% and 33.3%, respectively, in scarlet fever. It showed that Zeng-Ding phenomenon correlated with the time series and the kinds of diseases. Prediction from extrapolation model showed that there was significant difference in predictive agreement between two time series of 1975 to 1995 (65.5%) and 1985 to 1995 (37.0%) with chi 2 of 4.54 and P < 0.05, indicating a trend that predictive agreement increased with prolonging of time series, and a trend that predictive agreement for scarlet fever increased with decreasing of coefficients of correlation. CONCLUSION: Predictive value of the incidence data can be evaluated by their source and length of time series.

China↗
PubMed1999

[The impacts of sex hormones on histomorphometric and histological appearances of bone in ovariectomized rats].

OBJECTIVES: To demonstrate the histomorphometric and histological changes of bone 3 weeks after bilateral ovariectomy in rats and to investigate the impacts of 4 different hormone replacement therapies on the bone histomorphometric, histological appearances. METHODS: Bilateral ovariectomies were done on 41 female rats and sham operations on other 9 (sham group) respectively. After 3 weeks, 4 different treatments: i.e. Livial, Gevrine, Premarin, Weinian were initiated separately on each 8 ovariectomized rats for another 3 weeks. The remaining 9 were served as controls (OVX group). All rats were sacrificed either 3 weeks after ovariectomy/sham operation or at the end of hormone therapies. Their femoral bone mineral density (BMD) were measured by dual energy X-ray absorptiometry (DEXA). Specimens of proximal femur were embedded undecacifide for histomorphometric analysis and of distal femoral metaphysics were procured for scanning electron microscope (SEM) and pathologic examinations. RESULTS: (1) Three weeks after OVX, the femoral BMD, mean cortical thickness decreased significantly while the number of osteoclast increased significantly as compared with sham group. The trabecular became thinner and irregular which changed the bone microstructure in three dimension. (2) After treatment of 4 different preparations, the above parameters restored to various extents to the sham operation levels. Among them, there was greater increase of femoral BMD on the Livial and Gevrine group as compared with Premarin and Weinian group (P < 0.05). CONCLUSIONS: Bilateral ovariectomy induced increased osteoclast activity and bone turnover, therefore caused accelerated bone loss. Treatment with combined sex hormones preparation could inhibit bone absorption and stimulate bone formation, especially those containing androgenic activity could increase the BMD.

Anabolic Agents↗
PubMed1999

[Study of relation between ureaplasma urealyticum and fetal intrauterine growth retardation].

OBJECTIVE: To study the influences of Ureaplasma Urealyticum (UU) infection to fetal intrauterine growth. METHODS: Polymerase Chain Reaction was used to detect UU in samples of cervical secretions, umbilical blood and placenta. The study group included 50 women with neonatal birth weight below 2,500 g, 50 women with newborns birth weight above 2,500 g served as control group. RESULTS: Positive rate of UU in samples of cord blood and placenta and placental chorioamnionitis in study group were higher than that in the control group (P < 0.005 and P < 0.05). There was no significant difference of UU positive rate in cervical samples between two groups. The positive rate of UU in cases with chorioamnionitis was higher than that of cases with negative UU infection (P < 0.05). CONCLUSION: UU may interfere fetal intrauterine growth through infecting umbilical blood and placenta.

Adult↗
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↗