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Biomedical subjects

X Lü

Publications and source records attributed to X Lü.

At least 19 recordsLinked to original sources
PubMed2001

Genotype and allele frequency of the 27-bp tandem repeat polymorphism in the endothelial nitric oxide synthase gene in Chinese population.

Genotype and allele frequency of the polymorphic 27-bp repeat, a variable number of tandem repeats (VNTR) located in intron 4 of the endothelial nitric oxide synthase gene, were analyzed in 316 healthy Chinese individuals. Four genotypes, namely 6/5-repeats heterozygous, 5/5-repeats homozygous, 5/4-repeats heterozygous and 4/4-repeats homozygous, were identified. Both observed genotype and allele frequencies of this VNTR in Chinese were similar to those of Japanese, while the 4/4-repeats genotype differed significantly from that of Caucasians in Spain, and all ones did from those of African-American in United States.

Alleles↗
PubMed2001

[Expression of recombinant human Flt3 ligand in Escherichia coli and its purification and characterization].

OBJECTIVE: To establish a highly efficient expression system of recombinant human Flt3 ligand (rhFL) in E. coli and a suitable purification method of the expressed products. METHOD: Human FL encoding cDNA was introduced into pProEXHT plasmid to express a 6 x His-FL fusion protein in E. coli. The fusion protein expressed in inclusion body was isolated, solubilized and refolded, and then purified by chromatography on a metal-chelating affinity column (MCAC). Its activity was detected by stimulating the proliferation of CD(34)(+) cells. RESULT: The amount of rhFL expressed was about 15% of total bacterial proteins and the purity of rhFL was 90% after MCAC. The combination of rhFL, granulocyte colony-stimulating factor and erythropoietin could stimulate CD(34)(+) cells to a 400 fold expansion. CONCLUSION: The purified rhFL had a potent activity to stimulate hematopoietic stem cells to expanse in vitro.

Cell Proliferation↗
PubMed2001

[Study on apoptosis of human gastric adenocarcinoma cell SGC-7901 induced by aining in vitro and the cell cycle].

OBJECTIVE: To study the inducing apoptosis effect of Aining on human gastric adenocarcinoma cell in vitro. METHODS: Agarose gel electrophoresis (AGE) and flow cytometry (FMC) techniques were adopted to study the inducing apoptosis effect of Ainging on the human gastric adenocarcinoma cell. RESULTS: The human gastric adenocarcinoma cell's DNA was digested into fragments which gave rise to a characteristic "DNA Ladder" on agarose gel electrophoresis, while the percentage of apoptotic cells was 43.5%. But the blank group had neither DNA ladder, nor apoptotic peak. Cell cycle analysis showed that the proliferation index was 33.7% after the human gastric adenocarcinoma cells treated with Aining, and there was no cell phase specialty. CONCLUSION: Aining can induce human gastric adenocarcinoma cell apoptosis in vitro.

Adenocarcinoma↗
PubMed2001

[Culture and identify the endothelial cells of human umbilical vein].

In order to improve the routine culture method for vascular endothelial cells, endothelial cells of vein from newborn umbilical cord were successfully isolated with combined using 0.1% collagenase and 0.25% trypsin (1:1). The endothelial cells were further abrated by mechanical method. The composition of culture medium was simplified by not adding vascular endothelial cell growth factor and heparin. The cultured cells were verified as vascular endothelial cells by morphology, ultramicromorphology and immunohistochemistry.

Cell Culture Techniques↗
PubMed2001

[Study of quinolones resistance in Escherichia coli, Staphylococcus aureus and Pseudomonas areuginosa].

OBJECTIVE: To investigate the factors of quinolone-resistance mediating in Escherichia coli(E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas areuginosa(P. areuginosa) and examine the characteristic changes and quinolones resistance of these bacteria after exposing them to quinolones, dye-materials, and ultraviolet respectively. METHODS: The agar plate inoculating on surface and tube broth two-fold dilution methods were adopted. RESULTS: Quinolone-resistance was mainly mediated by repeated exposure of the bacteria to low level concentration of quinolone. No quinolone-resistance was found after exposure of the bacteria to ultra-violet and dye materials such as Ethidium bromide and Acry-orange. Among the three kinds of bacteria, E. coli tended to have stable high level of quinolone- resistance(MICs > or = 256 mg/L). S. aureus acquired mediate level of quinolone-resistance(MICs < or = 32 mg/L). P. aeruginosa acquired a high but not stable level(MICs > or = 256 mg/L) of resistance. These bacteria were cultured in the concentration of 1/2 x MIC, 1 x MIC, 2 x MIC, 4 x MIC, 5 x MIC ciprofloxacin, and were compared with those cultured in the same concentration of sparfloxacin and cefotaxime. After being affected by ciprofloxacin, the E. coli underwent apparent morphologic changes, such as becoming wider(2-3 times), longer(10-30 times), thread-like, and fewer in number. These changes were consistent with the increase of quinolone concentrations. The morphologic changes in P. aeruginosa and S. aureus were not so obvious as those in E. coli. Sparfloxacin and cefotaxime mainly led to the decrease in the numbers of bacteria. When the concentration of Sparfloxacin and cefotaxime were 4 x MICs, the changes of P. aeruginosa and S. aureus were less obvious. CONCLUSION: The bacteria's quinolone-resistance is mainly induced by the quinolone itself. The quinolone-resistance is more likely occur in E. coli than in P. aeruginosa and S. aureus. After exposure of the bacteria to ciprofloxacin, E. coli might have most apparent morphologic changes and occurrence resistance.

Anti-Infective Agents↗
PubMed2001

[The preparation of norA gene probe in Staphylococcus aureus].

OBJECTIVE: To prepare norA gene probe for studies on the mechanism of resistance to fluoroquinolones mediated by norA gene in S. aureus. METHODS: The Dig-labeled norA gene probe was made by PCR. RESULTS: This method is simple and feasible. We have got a lot of probes in a short time. The sensitivity of norA gene probe is high; the probe is secure, easy to use and can be stored for a long time. CONCLUSION: The probe is applicable to further studies on the mechanism of resistance to fluoroquinolones mediated by norA in S. aureus.

Anti-Infective Agents↗
PubMed2001

[The HVR genotypes and their relationship with the resistance of methicillin-resistant staphylococci].

OBJECTIVE: To investigate the HVR-PCR genotype of methicillin-resistant Staphylococci in local hospitals and compare it with the antibiograms, with aview to selecting effective antibacterial agents, moreover, to discuss preliminarily its role in molecular epidemiology. METHODS: The minimal inhibitory concentrations(MICs) of 86 MRSA, 10 MRSE(Mc'S. epidemidis), 5 MSSE(Mc'S. epidemidis), 8 MRSH(Mc'S. haemolyticus) and 5 MSSH(Mc'S. haemolyticus) clinical isolates collected from 4 local hospitals were tested by serial two-fold agar dilution method; their DNA were extracted by moved basic lytic method, whose polymerase chain reaction(PCR) products amplified, based on the size of mec-associated hypervariable region(HVR) were analyzed by PAG vertical and agarose gel electrophoresis. RESULTS: MRSA, MRSE and MRSH were grouped into 4, 3 and 2 HVR genotypes respectively according to the size of the PCR products. The PCR products amplified from 9 of 10 MRSE isolates were the same as the products amplified from MRSA isolates. MRSA strains in this study were mainly HVR genotypes A and D, which accounted for 52.32% and 39.53%; Genotypes B and C were the most multi-drug resistant, but genotype D was multi-sensitive. The I genotype of MRSE was multi-drug resistant, but its genotype III was multi-drug sensitive. The genotype a of MRSH was more resistant than genotype b. CONCLUSION: These results suggest that HVR-PCR genotype method is an easy and fast method for epidemiological investigation of nosocomial infections caused by MRSA, and it is helpful for clinical selection of antibacterial agents. This method can compare the mec determinants of MRSA and Mc'CNSt isolates and hence to search for the origin of the mec determinant.

Complementarity Determining Regions↗
PubMed2001

National survey on prevalence of cancer pain.

OBJECTIVE: To collect nationwide basic data about cancer related pain. METHODS: Sixty cancer patients in each province were randomly selected to participate in this survey. The subjects represented all stages of cancer, tumor sites, and different demographic characteristics. Two self-designed structured questionnaires including reasons, types of pain and pain management were used by patients and physicians respectively. Subjects were asked to report whether he/she had experienced any type of cancer related pain and filled out the equivalent questionnaire. The severity of pain was assessed by using "visual analogue scale". Original data input and analysis were using EPI-INFO software package. RESULTS: The result showed that 61.6% (958/1555) of patients had different types of cancer related pain. Majority of pain (85.1%) were caused by advanced cancer. The major reasons (64.4%) for poor management or impedimental factors of pain care are due to patient including over-concern on opioid analgesic addiction, reluctance to report pain or refused to use opioid analgesic until at times when pain is intolerable; 26.8% belonged to physician's reasons including fear to cause addiction on opioid and lack of knowledge about cancer pain management; 16.2% are due to lack of different kinds of opioid analgesic for use and 16.1% belonged to drug regulation. CONCLUSIONS: The results showed that majority of patients (61.6%) had different types of cancer related pain. In most of patients, cancer pain was relieved when they were treated. The major reason for under-treatment or impeded factors for effective relief of cancer pain was fear of opioid addiction by both medical professionals and patients.

Adolescent↗
PubMed2001

The tree shrew apolipoprotein C-I cDNA: sequence and its expression.

A rabbit anti-serum to tree shrew apolipoprotein C-I (apo C-I) was used to screen an expression cDNA library constructed by us from tree shrew (TS) liver tissue. Two apo C-I cDNA clones were obtained. The longer one consists of 380 nucleotides, including 21 bp and 95 bp at the 5' and 3' end of the non-translated regions respectively, and a 264-bp fragment in an open reading frame encoding 88 amino acids prepropeptide which contains 26 amino acids of signal peptide and a mature protein (62 amino acids). Comparing the amino-acid sequence deduced from this cDNA with those of the published mammalian apo C-Is reveals that it shared some structural similarity with rat, mouse and dog apo C-I, but it had 5 more amino acids than that of human and baboon. The expression of apo C-I mRNA in 8 different tissues were also assayed with Northern blot. The results demonstrated that liver had the highest expression, intestine had much less expression and no expression in other tissues, which is much different from human and other species. This study has laid down a good foundation for further studying on the function and the stucture of tree shrew apo C-I gene.

Amino Acid Sequence↗
PubMed2001

[The hygienic examination and quality research of Chinese crude drug scorpion].

We selected the method of hygienic test to determinate the infection of colibacilli, salmonelli, mixed bacteria, mould fungus and yeasts on Chinese crude drug scorpion from 29 commerical samples in different storaged period, habitats and commerical standard. The results showed there were not colibacilli and salmonelli in all 29 samples, but infectious mixed bacteria rate is 100%, which is 2.1 times more than salty scorpion in 29 tested samples, and the infectious fungi rate is 72.4%. The fungi of salty scorpion is 15% more than fresh scorpion. The quantity of infected yeasts on salty scorpion is much more than scorpion. There are 4 species of fungi such as Alternaria neesex Wallroth, Aspergillus fumigatus Fresenius, Nocarcia sp. and Tricophyton violaceum Sabouraud. Because of infectious pathogenic bacteria rate is so high, we suggest to increase the item of hygienic test to control the quality of crude drug scorpion and strengthen the administration of commerical drugs, so as to reduce the contaminative condition.

Animals↗
PubMed2000

[Wear study of dental restoration materials with a new study-system in vitro].

OBJECTIVE: To investigate abrasive wear of composite resins in vitro. METHODS: A chewing simulator was used to perform the abrasive wear of four composite resins in vitro and an accurate three-dimensional laser-scanning system was used to measure the abrasion los of the materials. RESULTS: According to worn volumes, the order of five materials is: Enamel < Targis Dentin < Dentacolor < Artglass < Vita Zeta. According to the worn-depthest-points, the order of five materials is: Enamel < Targis Dentin < Artglass < Dentacolor < Vita Zeta. CONCLUSION: Targis Dentin shows no significant difference on ware resistance from human enamel, while three other composite resins are poorer than human enamel. This system in vitro is effective, accurate, quick and economical.

Composite Resins↗
PubMed2000

[Study on uptake of fluoroquinolones by Staphylococcus aureus].

This study aimed to investigate the mechanism of Staphylococcus aureus' resistance to fluoroquinolones. The uptake of lomefloxacin, ofloxacin by Staphylococcus aureus and the effect of CCCP on the uptake were studied by the fluorescence method. The uptake of lomefloxacin, ofloxacin by sensitive organisms is higher than that by resistant organisms; CCCP had different influences on different organisms, but no significant difference between the effects of CCCP on sensitive strains and on resistant strains was noted. The uptake of lomefloxacin, ofloxacin by SA2-16 was much lower than that by SA2-16's parent, and after the addition of CCCP, the uptake of both quinolones by SA2-16 increased rapidly, but the concentration did not reach its parent's concentration in stable condition. These results indicate that the decreasing of the uptake of fluoroquinolones is one of the mechanisms responsible for Staphylococcus aureus to resistance fluoroquinolones, and as a mechanism of resistance to drugs, it plays different roles in different strains.

Anti-Infective Agents↗
PubMed1999

Aberrant positioning of trophoblast and lymphocytes in the feto-maternal interface with pre-eclampsia.

Pregnancy represents the growth of an allograft where fetal trophoblast cells evade immune rejection and invade maternal tissue. There should be a balance between fetal trophoblast and maternal immune-responsive cells and alterations in the proportion of these cells may relate to pregnancy disorders. To test this, the decidual tissue of placental bed biopsies was examined and trophoblast cells and lymphocytes were quantified morphometrically; spiral arteries were classified as unchanged, transformed or affected by acute atherosis. Normal pregnancy (n=19) was characterized by the transformation of about one half of all spiral arteries within the placental bed. We found that 40% of all lymphocytes were CD56+ uterine NK cells and 60%, CD3+ T-lymphocytes; about 30% of these were CD8+ T cells. Intrauterine growth retardation in the context of preeclampsia (n=15) was accompanied by reduced trophoblast numbers within smaller and more tortuous arteries and an increase in the proportion of CD56+ uterine NK cells and CD8+ T lymphocytes in the decidua (70% of all CD3+ cells). In the case of pre-eclampsia without fetal growth retardation (n=14) no increase in CD56+ uterine NK cells was seen, while CD8+ T lymphocytes were significantly increased compared with the normal level (50% of all CD3+ cells). Fetal growth retardation is associated with poor transformation of spiral arteries and characterized by an increase of uterine NK cells. Symptoms of pre-eclampsia are independently associated with an increase in the cytotoxic T subset of decidual lymphocytes. Pre-eclampsia and related fetal growth retardation are seemingly caused by an enhancement of the maternal cytotoxic defence against the fetal allograft.

Arteries↗
PubMed1999

[Application of in vitro micronucleus tests using L5178Y mouse lymphoma and WTK1 human lymphoblastoid cell lines to antimutagenicity assay].

In the in vitro micronucleus (MN) tests using L5178Y mouse lymphoma and WTK1 human lymphoblastoid cell lines, 2 well-known antimutagens, Vitamin C (Vc) and the sodium and copper salt of chlorophyll (Chl), were tested to evaluate their ability to inhibit the mutagenicity of mitomycin C(MMC). Three kinds of treatment were designed, namely the simultaneous treatment with Vc (or Chl) and MMC, the use of Vc (or Chl) before the use of MMC, and the use of Vc (or Chl) after the use of MMC. The results showed that Vc and Chl had no MN inductivity in the two cell lines; that simultaneous treatment with Vc and MMC and pre-treatment with Vc effectively reduced MMC-induced MN cell frequencies; and that simultaneous treatment and pre-treatment with Chl at dose level of 0.12 mg/ml, significantly reduced MMC-induced MN cell frequencies of L5178Y cells. The antimutagenic effect of Chl on WTK1 cells was found in simultaneous and pre-treatment at dose levels of 0.12 and 0.06 mg/ml.

Animals↗
PubMed1999

[Simultaneous determination of gibberellins A1 and A3 in foxtail millet seedlings by high performance liquid chromatography].

Gibberellin A1(GA1) and Gibberellin A3(GA3) in millet seedlings were simultaneously determined by HPLC on a Zorbax-ODS-C18 (4.6 mm x 250 mm, 10 microns) column, using a mobile phase consisting of V (0.02 mol/L phosphate buffer solution, pH 4.0):V(methanol) = 2.2:1, a flow rate of 0.8 mL/min and a UV detection at 210 nm. GA1 and GA3 were separated completely in 10 min. Correlation coefficients for linear equations were 0.9986 and 0.9978, recoveries were 102.54% and 99.59%, respectively. Two normal cultivars and their dwarf-mutants were determined by this method. The results showed that both GA1 and GA3 were discovered in foxtail millet seedling, and endogenous mass ratio of GA1 and GA3 in foxtail millet dwarf-mutants were significantly lower than those in normal cultivars, and the concentrations of endogenous GA1 and GA3 were important factors for plant-height.

English Abstract↗
PubMed1998

Targeted lymph-node immunization with whole inactivated simian immunodeficiency virus (SIV) or envelope and core subunit antigen vaccines does not reliably protect rhesus macaques from vaginal challenge with SIVmac251.

OBJECTIVE: Sexual transmission of HIV is the most common route of HIV transmission throughout the world. To prevent sexually transmitted HIV infection, a vaccine is urgently needed. A previous report demonstrated the targeted immunization of the iliac lymph nodes with simian immunodeficiency virus (SIV) subunits protects rhesus macaques from rectal challenge with SIV. We sought to determine whether this immunization strategy could protect rhesus macaques from vaginal challenge with SIV. DESIGN: Macaques were immunized with either whole-killed SIV or envelope and core subunit antigen vaccines. Using three independent groups, with three macaques in each group, macaques were immunized by the targeted iliac lymph-node (TILN) route, injecting the vaccine close to the iliac lymph nodes that drain the genital tract. RESULTS: The TILN immunization procedure induced high-titer SIV-specific immunoglobulin (Ig) G antibodies in serum in all animals and anti-SIV IgG and IgA antibodies in the cervicovaginal secretions of most animals. After a series of three or four TILN immunizations, the animals were intravaginally challenged with SIVmac251. All animals became virus isolation-positive, except one animal immunized with SIV p27 and gp120. This animal was virus isolation-negative but SIV DNA proviral sequences were detected in peripheral blood mononuclear cells. CONCLUSIONS: In this series of studies, reliable protection from vaginal transmission of SIV was not achieved by the TILN immunization procedure.

Animals↗