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Biomedical subjects

Y Sun

Publications and source records attributed to Y Sun.

At least 307 records · Page 17Linked to original sources
PubMed2000

[The common C677T polymorphism in the methylenetetrahydrofolate reductase gene is associated with neural tube defects and preeclampsia].

OBJECTIVE: To assess whether methylenetetrahydrofolate reductase(MTHFR) gene C677T polymorphism is associated with neural tube defects and preeclampsia. METHODS: Twenty- four mothers who had given birth to normal children, 27 mothers who had given birth to NTDs children, 120 normal women, and 57 women who had suffered from preeclampsia were genotyped for C677T polymorphism by using PCR/RFLP method. RESULTS: (1) VV genotype frequency in the normal mothers group it was 0.13, while in the NTDs mothers group it was 0.33; mothers with VV genotype were at 3 times increased risk to have a NTDs child, compared with the normal mothers. (2) In the normal women group VV genotype frequency was 0.15, while in the preeclampsia women group it was 0.31; women with VV genotype were at 2.5 times increased risk to have preeclampsia, compared with the normal women. CONCLUSION: The authors believe that MTHFR VV genotype is associated with the development of NTDs and preeclampsia.

Female↗
PubMed2000

Binding of 14-3-3beta to the carboxyl terminus of Wee1 increases Wee1 stability, kinase activity, and G2-M cell population.

Wee1 protein kinase plays an important regulatory role in cell cycle progression. It inhibits Cdc-2 activity by phosphorylating Tyr15 and arrests cells at G2-M phase. In an attempt to understand Wee1 regulation during cell cycle, yeast two-hybrid screening was used to identify Wee1-binding protein(s). Five of the eight positive clones identified encode 14-3-3beta. In vivo binding assay in 293 cells showed that both full-length and NH2-terminal truncated Wee1 bind with 14-3-3beta. The 14-3-3beta binding site was mapped to a COOH-terminal consensus motif, RSVSLT (codons 639 to 646). Binding with 14-3-3beta increases the protein level of full-length Wee1 but not of the truncated Wee1. Accompanying the protein level increases, the kinase activity of Wee1 also increases when coexpressed with 14-3-3beta. Increased Wee1 protein level/enzymatic activity is accountable, at least in part, to an increased Wee1 protein half-life when coexpressed with 14-3-3beta. The protein half-life of the NH2-terminal truncated Wee1 is much longer than that of the full-length protein and is not affected by 14-3-3beta cotransfection. Biologically, 14-3-3beta/Wee1 coexpression increases the cell population at G2-M phase. Thus, Wee1 binding with 14-3-3beta increases its biochemical activity as well as its biological function. The finding reveals a novel mechanism by which 14-3-3 regulates G2-M arrest and suggests that the NH2-terminal domain of Wee1 contains a negative regulatory sequence that determines Wee1 stability.

14-3-3 Proteins↗
PubMed2000

Linkage of the genes controlling natural killer cell activity to HLA-B.

OBJECTIVE: To study whether there is a relationship between HLA-B alleles and low natural killer(NK) cell activity in Chinese. METHODS: The subjects were 34 unrelated healthy individuals (10 males and 24 females), aged 25-60 years, and 31 individuals (17 males and 14 females) from 11 families, aged 22-70 years, previously genotyped for HLA class I, II, complotypes and haplotypes that were assigned based on family studies. The unrelated individuals were typed for HLA-A, -B antigen by a microcytotoxicity assay and all the subjects were tested for NK cell activity by lactate dehydrogenase (LDH) enzyme-release assay. RESULTS: Statistical analysis showed that 30 lysis unit(LU) was the cutoff value of low and high NK reactors. The frequency of low reactor individuals homozygous for HLA-B was significantly higher than that for those for HLA-DR(P< 0. 05). The associated genes included HLA-B13, B40, B46, B7, B57, defined as NKB1 genes, and HLA-B44 as NKB2 gene. Family studies provide further evidence that the genes controlling low NK cell activity were located in the MHC region and it was a recessive trait. CONCLUSION: There were recessive genes associated with HLA-B controlling low NK cell activity in Chinese. The NKB alleles were partly different from those found in Caucasian.

Adult↗
PubMed2000

[Phylogenetic study of Artemia from China using RAPD and AFLP markers].

We have applied the techniques of RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism) to the analysis of the relationships among Artemia species and strains. RAPD markers were successfully employed to detect diversity and genetic differentiation among four species of brine shrimp: A. franciscana, A. urmiana, A. sinica, and A. parthenogenetica. Seventy, ten-base synthetic oligonucleotides were used to amplify a total of 458 distinct fragments. DNA polymorphisms were found in all the species examined; The highest percentage of polymorphic bands found in A. parthenogenetica, was 28.8 per cent. There are significant differences between bisexual sibling species and parthenogenetic populations. A. parthenogenetica provided 94 specific molecular markers, while bisexual sibling species gave 27 specific molecular markers. A. sinica is a species distinct from the other Old World bisexual species. AFLP were used to analyze 15 Artemia species and strains for genetic diversity. They are extremely sensitive to even a small sequence variation and more polymorphism than RAPD. Using only 10 pairs of primer combinations, we detected 580 AFLP bands of which were polymerphic. The RAPD and AFLP techniques are powerful DNA fingerprinting methods for classification of Artemia species and strains.

Animals↗
PubMed2000

[Reactivation of denatured lysozyme with immobilized molecular chaperones GroE].

The molecular chaperones GroEL and GroES were expressed in recombinant E. coli and purified by anion exchange chromatography. The renaturation of the denatured lysozyme with the free and immobilized GroEL/ES or GroEL was studied. We show here that using free GroEL alone could reactive the denatured lysozyme up to a relative activity of over 90%. The immobilized GroEL was also effective for promoting lysozyme refolding. Moreover, the optimal temperature (i.e., 37 degrees C) and (pH(i.e., 6 to 8) for the immobilizde GroEL-facilitated lysozyme refolding operation were determined. Under the optimal condition, the activity of lysozyme could be recovered up to 85%. In addition, the immobilized GroEL was repeatedly used five times without loss of its renaturation ability, indicating its potentiality to be used in practical downstream bioprocesses.

Chaperonin 10↗
PubMed2000

Studies of MAL gene in human esophageal cancer by RNA in situ hybridization.

OBJECTIVE: To observe the expression of MAL gene mRNA in esophageal cancer tissue and adjacent epithelial mucosa. METHODS: Non-radioactive RNA in situ hybridization. RESULTS: MAL gene was expressed in all epithelia of 33 matched samples but only in 8 of esophageal cancer tissues. Differential expression between esophageal cancer tissues and adjacent epithelia was not related to clinical parameters. CONCLUSION: Down-regulation of MAL may be an important event in the development of esophageal cancer.

Down-Regulation↗
PubMed2000

Analysis of DYS19 and DYS287 polymorphisms in the Han population and three other ethnic groups of northeast China.

The allelic distribution of the Y-chromosome specific microsatellite DYS19 in the Han population and in the Daur, Oroqen and Ewenki ethnic groups (Northeast China) was analyzed by PCR and denatured polyacrylamide gel electrophoresis. The allelic distribution in the Han population group is as follows: A = 2.90%, B = 26.09%, C = 26.09%, D = 29.98%, E = 15.94%. This allelic distribution differs statistically significant from that observed in the three other ethnic groups (p < 0.05). Furthermore the polymorphism of the Y-chromosome specific Alu insert sequence DYS287 was tested in these four groups. However, no Alu sequence insert was found.

Alleles↗
PubMed2000

Analysis of polymorphic mitochondrial DNA in the Han population and three other ethnic groups of northeast China.

By means of the PCR-RFLP technique the polymorphism of a 465 fragment of mtDNA D loop was analyzed in 36 individuals of the Northeast Han, 30 individuals of the Daur, 32 individuals of the Oroqen and 30 individuals of the Ewenki. All these individuals were randomly selected and are healthy. 27 restriction patterns were obtained by assaying the RFLP fragments of the mtDNA D loop. The mean nucleid acid substitute frequencies at each site are the following: Northeast Han = 0.0291, Oroqen = 0.0477, Ewenki = 0.0563, Daur = 0.0541. The genetic relationship between these four populations was analyzed by the UPG cluster analysis.

Asian People↗
PubMed2000

[Expression of bcl-2 gene in relation to histologic type and grade, and prognosis of breast cancer].

OBJECTIVE: To ascertain whether bcl-2 gene expression is related to histologic type and grade, and prognosis of breast cancer and its prognosis. METHODS: Expression of bcl-2 protein was examined immunohistochemically in 85 cases of breast cancer patients with > or = 5 years of follow-up. RESULTS: Expression of bcl-2 protein was detectable in 68.2% of breast cancer specimens. It was not related to histologic type, but to histologic grade of the cancer. In grade I, bcl-2 was positive in 95.2% of the specimens which was significantly higher than that in grade II (64.6%) and grade III (25.0%)(P < 0.01). The positive rate of bcl-2 expression was 75.9% in patients who survived > or = 5 years as compared to that (51.6%) in patients survived < 5 years (P < 0.05). CONCLUSION: Expression of bcl-2 occurs more frequently in well differentiated breast cancer. It is associated with better prognosis of the patients.

Adult↗
PubMed2000

[Epidemiological analysis of extrapulmonary tuberculosis in Shanghai].

OBJECTIVES: To find out the epidemiological characteristics of extrapulmonary tuberculosis (TB) in Shanghai, and to explore value of this surveillance. METHODS: Distribution of extrapulmonary TB for sex, age and suffering site 1996-1999 were analyzed. In addition, its incidence trend and mortality were also investigated. All registered cases from ten urban districts of Shanghai were included. RESULTS: The new registration rates of extrapulmonary TB 1996-1999 were 4.65-5.78/100,000. The proportion of extrapulmonary TB to all TB was 9.7%-11.8%. The extrapulmonary TB accounted for 14.1%-17.6% of all death due to TB. The rankings of extrapulmonary TB were as follows: lymph node TB (38.3%), bone and joint TB (19.9%), urinary and genital TB (16.7%), intestine and peritoneum TB (9.1%), cerebral and nervous TB (6.4%). The sex ratio of male to female was 1 to 1.35. The new registration rates of extrapulmonary TB increased with age except that of cerebral and nervous TB was the highest in middle and young age group. CONCLUSIONS: Surveillance on extrapulmonary TB is an important part of TB surveillance, with significant value for TB control.

Age of Onset↗
PubMed2000

[The arboviruses of genus alphavirus family togaviridae were isolated from mosquitoes captured from Yantai].

OBJECTIVE: To isolate arbovirus from mosquitoes caught from Yantai. METHODS: The isolated viruses were tested for their physico- chemical properties, examined by electron microscopy and specific immuno-reactivity. RESULTS: Fifteen strains of virus were isolated from mosquitoes in 1994 from Yantai. Three of them were further assayed. The results showed that the viruses could multiply on C6/36 cell and produce typical cytopathogenic effect. The viruses couldn't cause regular sickness and death of suckling mice by intracerebral inoculation. The viruses were sensitive to ether, but resistant to 5, -Idu. One sample was examined with electron microscope, and spherical virus particles were observed. The diameter of the virus particles is about 55 +/- 2. 3nm. It did not react with the JBE virus and Bunyaviridae group specific immuno-ascitic fluids but cross-reacted with the group A Togaviridae specific immuno-ascitic fluid. CONCLUSIONS: The results showed that the viruses isolated from Yantai belong to alphavirus of togaviridae.

Animals↗
PubMed2000

[Distribution and transferring of carbon in kast soil system of peak forest depression in humid subtropical region].

Taking Guilin Yaji Karst Experiment Site as an exemple and with the methods of field monitoring and laboratory analysis, this paper studied the distribution and transferring of carbon in the karst soil system of peak forest depression in the humid subtropical region of China. The carbon pools in biomass, litters and soil organic matter(SOM) and their mobility as expressed by oxidizability and decomposition rate of SOM, the concentration of soil CO2 and the emission rate of CO2 from soil were investigated. The mobile carbon pool in the system supplied a rich source of CO2, which drived the karst process. When active karst process happened in Spring and Summer, over 60% of carbon in the output water was derived from soil CO2, as traced by delta 13 C distribution in the system. Therefore, owing to the carbon transfer in the pathway of air-plant-soil-water, karst process took place rather under soil-rock-water interface than under air-rock-water interface. Thus, the epigenetic karst process was driven and accelerated by soil as an interface of carbon environmental geochemistry.

Carbon↗
PubMed2000

[Gastric evacuation rate of black sea bream(Sparus macrocephalus)].

The gastric evacuation rate of black sea bream(Sparus macrocephalus) weighing 20-40 g was determined at 18 degrees C in laboratory. Three mathematical models were applied to simulate it. The result indicated that all of these three kinds of models fitted to the experiment data, while statistical analysis showed that the linear model was the best, whether the remained food in stomach was expressed by wet weight or dry weight. When the remained food in stomach was expressed by wet weight, the model was Y = 1.14 - 0.06 t(r2 = 0.82, p < 0.001), and by dry weight, it was Y = 1.36 - 0.07 t(r2 = 0.62, p < 0.001). The gastric evacuation rate of black sea bream was 6-7% of consumed food per hour at 18 degrees C.

Animals↗
PubMed2000

[Community characteristics of soil ciliated protozoan at Dapeng Peninsula].

With the qualitative and quantitative analysis, the community characteristics of soil ciliated protozoan sample from Dapeng Peninsula, Guangdong province was studied. The comunity consisted of 42 species of ciliates, including 4 new records in China. The major species were Cohnilembus vexillarius, Colpoda henneguy, Clopoda steinii, Histriculus muscorum, Gonostomum affine, Drepanomonas revolata, Leptopharynx costatus and Dileptus alpinus. Culturing the ciliated protozoan in laboratory showed that the species succession of domimant speies during the culture was from Gonostomum affine and Histriculus muscorum n the early stage to Cohnilembus vexillaria, and then to Colpoda spp. The difference of soil cliated communities between in Dapeng Peninsula and other regions was compared, and the possible factors affecting the difference were analyzed.

Animals↗
PubMed2000

[Assimilation efficiency of pacific oyster Crassortrea gigas].

The effects of body size, food density and its quality on assimilation efficiency of pacific oyster (Crassostrea gigas) were studied under artificial conditions in laboratory. The experimental results show that the filtration and ingestion rates of pacific oyster increased with its body size, which tallied with power function. The assimilation efficiency of pacific oyster was not significantly correlated with its body size, but correlated positively with the organic matter content of food and negatively with food density.

Animal Nutritional Physiological Phenomena↗
PubMed2000

[Environment capacity of eco-tourism resort].

The results of quantitative analysis on the amount of tourist, service-environment capacity, eco-environment capacity, and their relations in Five-finger Mountain eco-tourism resort indicate that the amount of tourist in common situation and in its extreme was 1918 and 2301 visitor-hour per day, and the service-environment capacity and eco-environment capacity were 6000 and 2400 visitor-hour per day, respectively. The eco-environment capacity was smaller than its service-environment capacity, and would become the first limiting factor to the increase of tourist amount, which was mainly due to the ecological fragility of resort, the lower resistance of biological communities to the disturbance, and the slower speed of ecosystem restoration after its being destroyed.

Ecosystem↗
PubMed2000

Chinese-made electrolytic detachable coil in the embolization of a dog aneurysmal model.

OBJECTIVE: To develop a Chinese-made electrolytic detachable coil (CEDC) that would allow patients to enjoy the benefit of electrolytic detachable coil without having to rely on the expensive Guglielmi detachable coil (GDC), and to test the safety and efficiency of CEDC. METHODS: Radiopacity of the marker of the CEDC was tested. The anti-strain force of coils and connection points were measured. In vitro and in vivo electrolyses were conducted. We produced 21 aneurysm models including lateral, bifurcation, and terminal aneurysm models, and embolized 18 models with CEDC. RESULTS: Radiopacity of the marker was satisfactory. Anti-strain of the coil and the connection point have shown the safety and efficiency of CEDC. Electrolysis in vitro and vivo, was similar to that of GDC. 83% of the aneurysm models were completely occluded. Coils were found to induce thrombosis in the aneurysm cavity, and could lead to a new endothelium over the entrance of the aneurysm, with organized tissue replacing thrombosis in 2 months. CONCLUSIONS: CEDC is as efficient and safe as GDC. The marker, the ability to induce thrombosis inside the sac and the growth of new endothelium over the orifice are very satisfactory.

Animals↗