Biomedical subjects

X Cui

Publications and source records attributed to X Cui.

At least 73 records · Page 4Linked to original sources

PubMed2000

[Inhibition of growth and metastasis of human giant cell carcinoma of the lung by transfection of antisense VEGF121 cDNA].

OBJECTIVE: To explore the effects of blocking the VEGF/VEGF receptor paracrine pathway on growth and metastasis of human lung carcinoma cell line PG and to evaluate its potential application in gene therapy of cancer. METHODS: The eukaryotic expression vectors bearing either sense-VEGF121 cDNA or antisense-VEGF121 cDNA was constructed and transfected into PG cells. In vitro and in vivo tests such as Northern blotting hybridization, Western blotting immunochemistry analysis, as well as xenografting in nude mice were used to analyze the effect of antisense-VEGF. RESULTS: The transfectants stably expressing antisense VEGF121 were observed to produce markedly reduced 3.3 kb VEGF mRNA and 45 KD, 41 KD, 32KD VEGF proteins. When xenografted s.c. into nude mice, growth and metastasis of the antisense-VEGF transfected cell lines were greatly inhibited when compared with control cells. CONCLUSION: Antisense VEGF gene significantly inhibited tumor growth and metastasis and may provide an experimental example for the development of antiangiogenic gene therapy.

Animals↗

PubMed2000

[Mobilization of autologous peripheral blood stem cells by chemotherapy and recombinant granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF)].

OBJECTIVE: To observe the efficacy of chemotherapy and recombinant granulocyte colony-stimulating factor (G-CSF, Glycosylated) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in autologous peripheral blood stem cells (APBSC) mobilization. METHODS: The mobilization regimen: CBP 350 mg/m(2) intravenously injected at day 1, Vp16 350 mg/m(2) intravenously injected from day 1 to day 3. G-CSF and GM-CSF 5 microg x kg(-1) x d(-1) each, subcutaneously injected and DXM 5 mg/d intramuscularly injected, from the day of white blood cell (WBC) recovery to (2.4 - 6.4) x 10(9)/L from nadir to the day before the end of APBSC harvesting. APBSC harvesting started when WBC > 20.0 x 10(9)/L and ended when accumulated mononuclear cells (MNC) > 5 x 10(8)/kg. CFU-GM assay and CD(34)(+) cells counting of the APBSC were performed. RESULTS: Twenty cases underwent APBSC mobilization. APBSC harvest began at day 22.15 +/- 3.66 for two successive days. Accumulated MNC was (5.93 +/- 1.62) x 10(8)/kg, CD(34)(+) cells (23.10 +/- 11.53) x 10(6)/kg and CFU-GM (3.44 +/- 2.85) x 10(5)/kg. No severe toxicity was observed. Hematopoiesis was well reconstituted in 8 patients received single and in 1 patient received double APBSC transplantations. CONCLUSION: Chemotherapy combined with G-CSF + GM-CSF was a safe and highly effective method for APBSC mobilization.

Adult↗

PubMed1999

Anaerobic microbes: oxygen detoxification without superoxide dismutase.

Superoxide reductase from the hyperthermophilic anaerobe Pyrococcus furiosus uses electrons from reduced nicotinamide adenine dinucleotide phosphate, by way of rubredoxin and an oxidoreductase, to reduce superoxide to hydrogen peroxide, which is then reduced to water by peroxidases. Unlike superoxide dismutase, the enzyme that protects aerobes from the toxic effects of oxygen, SOR does not catalyze the production of oxygen from superoxide and therefore confers a selective advantage on anaerobes. Superoxide reductase and associated proteins are catalytically active 80 degrees C below the optimum growth temperature (100 degrees C) of P. furiosus, conditions under which the organism is likely to be exposed to oxygen.

Acetylation↗

PubMed1999

The XRCC2 and XRCC3 repair genes are required for chromosome stability in mammalian cells.

The irs1 and irs1SF hamster cell lines are mutated for the XRCC2 and XRCC3 genes, respectively. Both show heightened sensitivity to ionizing radiation and particularly to the DNA cross-linking chemical mitomycin C (MMC). Frequencies of spontaneous chromosomal aberration have previously been reported to be higher in these two cell lines than in parental, wild-type cell lines. Microcell-mediated chromosome transfer was used to introduce complementing or non-complementing human chromosomes into each cell line. irs1 cells received human chromosome 7 (which contains the human XRCC2 gene) or, as a control, human chromosome 4. irs1SF cells received human chromosome 14 (which contains the XRCC3 gene) or human chromosome 7. For each set of hybrid cell lines, clones carrying the complementing human chromosome recovered MMC resistance to near-wild-type levels, while control clones carrying noncomplementing chromosomes remained sensitive to MMC. Fluorescence in situ hybridization with a human-specific probe revealed that the human chromosome in complemented clones remained intact in almost all cells even after extended passage. However, the human chromosome in noncomplemented clones frequently underwent chromosome rearrangements including breaks, deletions, and translocations. Chromosome aberrations accumulated slowly in the noncomplemented clones over subsequent passages, with some particular deletions and unbalanced translocations persistently transmitted throughout individual subclones. Our results indicate that the XRCC2 and XRCC3 genes, which are now considered members of the RAD51 gene family, play essential roles in maintaining chromosome stability during cell division. This may reflect roles in DNA repair, possibly via homologous recombination.

Animals↗

PubMed1999

Decreased p27(Kip1) expression and cyclin D1 overexpression, alone and in combination, influence recurrence and survival of patients with resectable extrahepatic bile duct carcinoma.

This study was undertaken to identify potential abnormalities of p27(Kip1) and cyclin D1 expression in extrahepatic bile duct carcinomas and to assess the prognostic significance of p27(Kip1) and cyclin D1 levels for patients with this disease. Decreased p27(Kip1) expression (<50% nuclei staining) and cyclin D1 overexpression (>5% nuclei staining) was observed immunohistochemically in 19 (56%) and 23 (68%) of the 34 tumors examined, respectively. Both decreased p27(Kip1) and cyclin D1 overexpression were associated with relapse (P =.0005 for p27(Kip1) and P =.0004 for cyclin D1). Kaplan-Meier curves showed that both decreased p27(Kip1) and cyclin D1 overexpression correlate significantly with shortened survival rates (for p27(Kip1), P =.0419 and P =.002 for overall and disease-free survival; for cyclin D1, P =.0392 and P =.0021 for overall and disease-free survival). Cox regression model analyses identified decreased p27(Kip1) and cyclin D1 overexpression as independent markers predicting death from relapse (P =.0371, risk ratio: 3.891 for p27(Kip1); P =.0429, risk ratio: 8.31 for cyclin D1). Decreased p27(Kip1) was associated with cyclin D1 overexpression (P =.0202), and coincident abnormalities of the 2 proteins occurred in 16 of the 34 (47%) tumors, indicating that extrahepatic bile duct carcinoma progression may require synchronous dysfunction of p27(Kip1) and cyclin D1 in about half of patients. Patients with tumors showing coincident abnormalities of p27(Kip1) and cyclin D1 showed even more frequent recurrence than patients with an alteration in only 1 of the 2 proteins. In conclusion, decreased p27(Kip1) expression and cyclin D1 overexpression, alone and in combination, predict poor prognosis in patients with resectable extrahepatic bile duct carcinoma.

Aged↗

PubMed1999

In vitro expansion of a multipotent population of human neural progenitor cells.

The isolation and expansion of human neural progenitor cells have important potential clinical applications, because these cells may be used as graft material in cell therapies to regenerate tissue and/or function in patients with central nervous system (CNS) disorders. This paper describes a continuously dividing multipotent population of progenitor cells in the human embryonic forebrain that can be propagated in vitro. These cells can be maintained and expanded using a serum-free defined medium containing basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF), and epidermal growth factor (EGF). Using these three factors, the cell cultures expand and remain multipotent for at least 1 year in vitro. This period of expansion results in a 10(7)-fold increase of this heterogeneous population of cells. Upon differentiation, they form neurons, astrocytes, and oligodendrocytes, the three main phenotypes in the CNS. Moreover, GABA-immunoreactive and tyrosine hydroxylase-immunoreactive neurons can be identified. These results demonstrate the feasibility of long-term in vitro expansion of human neural progenitor cells. The advantages of such a population of neural precursors for allogeneic transplantation include the ability to provide an expandable, well-characterized, defined cell source which can form specific neuronal or glial subtypes.

Brain↗

PubMed1999

Immunofluorescent evidence of the platelet-activating factor receptor on human spermatozoa.

OBJECTIVE: To determine the presence of the platelet-activating factor (PAF) receptor on human spermatozoa. DESIGN: Prospective analysis. SETTING: University-based reproductive biology laboratory. PATIENT(S): Spermatozoa obtained from men undergoing routine semen analysis. INTERVENTION(S): Spermatozoa (n = 10) were exposed to PAF, sheep anti-PAF antibody, and fluorescein isothiocyanate-conjugated rabbit antisheep antibody, and then evaluated by fluorescent microscopy. MAIN OUTCOME MEASURE(S): Assessment of fluorescent intensity at four locations on the spermatozoa (tail, midpiece, proximal head, and acrosome region). RESULT(S): Immunofluorescence demonstrated the presence of the PAF receptor on human spermatozoa. The PAF receptor was most prevalent at two sites on the spermatozoa: the midpiece and the proximal head. CONCLUSION(S): The PAF receptor is present on human spermatozoa. Platelet-activating factor may affect the motility of spermatozoa through a receptor-mediated mechanism at the midpiece and/or proximal head.

Fluorescent Antibody Technique↗

PubMed1999

Electron transfer between ferrocene-modified Au/octadecanethiol/lipid BLM electrode and redox couples in solution.

Bilayers incorporated with ferrocene consisting of self-assembled octadecanethiol and lipid monolayer on gold substrates were fabricated. Its electrochemical behaviors in solutions containing different redox couples were investigated by cyclic voltammetry and ac impedance. The transmembrane electron transfer reaction across octadecanethiol self-assembled film and an adsorbed phospholipid layer mediated by ferrocene have been observed in the solution of Fe(CN)6(3-/4-). The formal potential difference between mediator in bilayer lipid membrane (BLM) and redox couple in solution has a great impact on the transmembrane electron transfer behavior. The ferrocene-modified BLM electrodes might be useful for constructing a bilayer-based electrochemical current rectifying device.

Algorithms↗

PubMed1999

Unmodified supported thiol/lipid bilayers: studies of structural disorder and conducting mechanism by cyclic voltammetry and AC impedance.

Supported thiol/lipid bilayer assembly, one of the most spectacular bilayer systems in recent years, has provided a good model to study biomembranes because of its high mechanical stability. In this work, the structural and conducting property of unmodified Au supported octadecanethiol/phosphatidylcholine bilayers were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The forming process of bilayer was monitored by capacitance plane plot. The normalized membrane capacitance of supported bilayer is 0.52 microF cm(-2). Kinetically controlled voltammograms determined by Butler-Volmer equation were obtained for both thiol monolayer and thiol/lipid bilayer in linear sweep voltammetry. Results of EIS experiment indicate that collapsed sites and pinhole defects exist in thiol monolayer and lipid monolayer, respectively. The difference between the values of experimental and theoretical standard electron transfer rate constant indicates that the conducting mechanism of Au supported thiol monolayer is electron tunneling at collapsed sites. The conducting mechanism of Au supported thiol/lipid bilayer is attributed as the following: the electroactive species could diffuse through pinholes in the lipid monolayer and reach collapsed sites in thiol monolayer, where electron transfer occurs via a tunneling process. The fractional coverage of the lipid monolayer measure by EIS experiments is about 0.98 or higher.

Electrochemistry↗

PubMed1999

Inactivating mutations and overexpression of BCL10, a caspase recruitment domain-containing gene, in MALT lymphoma with t(1;14)(p22;q32).

Mucosa-associated lymphoid tissue (MALT) lymphomas most frequently involve the gastrointestinal tract and are the most common subset of extranodal non-Hodgkin lymphoma (NHL). Here we describe overexpression of BCL10, a novel apoptotic signalling gene that encodes an amino-terminal caspase recruitment domain (CARD), in MALT lymphomas due to the recurrent t(1;14)(p22;q32). BCL10 cDNAs from t(1;14)-positive MALT tumours contained a variety of mutations, most resulting in truncations either in or carboxy terminal to the CARD. Wild-type BCL10 activated NF-kappaB but induced apoptosis of MCF7 and 293 cells. CARD-truncation mutants were unable to induce cell death or activate NF-kappaB, whereas mutants with C-terminal truncations retained NF-kappaB activation but did not induce apoptosis. Mutant BCL10 overexpression might have a twofold lymphomagenic effect: loss of BCL10 pro-apoptosis may confer a survival advantage to MALT B-cells, and constitutive NF-kappaB activation may provide both anti-apoptotic and proliferative signals mediated via its transcriptional targets.

Adaptor Proteins, Signal Transducing↗

PubMed1999

Immunogold labeling of rosette terminal cellulose-synthesizing complexes in the vascular plant vigna angularis

The catalytic subunit of cellulose synthase is shown to be associated with the putative cellulose-synthesizing complex (rosette terminal complex [TC]) in vascular plants. The catalytic subunit domain of cotton cellulose synthase was cloned using a primer based on a rice expressed sequence tag (D41261) from which a specific primer was constructed to run a polymerase chain reaction that used a cDNA library from 24 days postanthesis cotton fibers as a template. The catalytic region of cotton cellulose synthase was expressed in Escherichia coli, and polyclonal antisera were produced. Colloidal gold coupled to goat anti-rabbit secondary antibodies provided a tag for visualization of the catalytic region of cellulose synthase during transmission electron microscopy. With a freeze-fracture replica labeling technique, the antibodies specifically localized to rosette TCs in the plasma membrane on the P-fracture face. Antibodies did not specifically label any structures on the E-fracture face. Significantly, a greater number of immune probes labeled the rosette TCs (i.e., gold particles were 20 nm or closer to the edge of the rosette TC) than did preimmune probes. These experiments confirm the long-held hypothesis that cellulose synthase is a component of the rosette TC in vascular plants, proving that the enzyme complex resides within the structure first described by freeze fracture in 1980. In addition, this study provides independent proof that the CelA gene is in fact one of the genes for cellulose synthase in vascular plants.

Journal Article↗

PubMed1999

Effect of Escherichia coli cytotoxic necrotizing factor 1 on repair of human bladder cell monolayers in vitro.

We hypothesized that Escherichia coli cytotoxic necrotizing factor 1 (CNF1) might impair migration or proliferation of bladder cells and could potentially interfere with repair of the bladder epithelium. Using experimentally wounded human T24 bladder epithelial cell monolayers as an in vitro model, we found that both the number of T24 cells and the maximum distance they migrated into wounded regions was significantly decreased by bacterial extracts containing E. coli CNF1.

Bacterial Toxins↗

PubMed1999

Orally administered Panax ginseng extract decreases platelet adhesiveness in 66% hepatectomized rats.

The effect of oral administration of Panax ginseng extract (GE) on platelet adhesiveness was examined in 66% hepatectomized rats. A significant decrease in platelet adhesiveness was obtained when 125 mg/kg/day GE was administered for 6 days before and after hepatectomy. The total cholesterol concentration in the serum was also decreased by GE administration. Food intake was unaffected by GE administration. Serum parameters indicating liver and kidney function were unchanged after GE administration except for lipid metabolic parameters. Because enhanced platelet adhesiveness and hyperlipidemia induces atherosclerosis, these results suggest that orally administered GE is capable of improving the atherosclerotic condition associated with hepatectomy.

Animals↗

PubMed1999

Effects of lu-duo-wei capsule on prolonging life span of housefly and Drosophila melanogaster.

Lu-Duo-Wei capsule is a product of Chinese medicine having high efficacy in scavenging superoxide and hydroxyl radicals. It contains antioxidants, which may increase longevity, but whether Lu-Duo-Wei capsule has such an effect is unknown. In this study, supplementing the basic diet with Lu-Duo-Wei resulted in prolonging the life span of houseflies and fruit flies. Moreover, the effect of prolonging the life span of houseflies by Lu-Duo-Wei was significantly higher than that of tea polyphenol. The result not only confirms our previous report but also supports the free radical theory of aging.

Animals↗

PubMed1999

[Role of endothelin and nitric oxide in early gut ischemia].

OBJECTIVE: Inadequate perfusion in splanchnic organs and especially in the gut during acute burn period has been reported in many conventionally "successfully" resuscitated patients, but the mechanisms still remain unclear and its early preventive measures need to be further studied. The aim of this study is to evaluate the role of endothelin and nitric oxide in gut ischemia. METHODS: Eighteen male pigs were randomly assigned to one of the three groups: group C, a sham burn group that was subjected to all surgical procedures except burn; group B, sustained 30% TBSA cutaneous thermal burn; Group N, NO donor (C87-3754) was given intravenously (0.0125 mg.kg-1.min-1) at the beginning of resuscitation. RESULTS: In group B, PVF decreased rapidly after burn, and did not recover in the observation period (72 h), ET levels in portal blood and intestinal tissue elevated contrary to the changes in NO. In group N, PVF was higher than in group B. CONCLUSION: 1. Changes in ET and NO may influence the protal blood flow. 2. NO donor was proved to be beneficial in improving GI tissue perfusion by releasing NO.

Animals↗

PubMed1999

[Surgical treatment of gastric cancer in stage T1/T2: an reevaluation of the clinical significance of early gastric cancer].

OBJECTIVE: To evaluate the clinical significance of early gastric cancer by means of an analysis of the results of surgical treatment of gastric cancer in stage T1/T2. METHODS: A retrospective review and survival analysis of 132 patients with stage T1/T2 stomach cancer treated from 1983 through 1993 was performed. RESULTS: The average tumor size, lymph node involvement, postoperative recurrence and survival rate were significantly different between gastric cancer in stage T1 and T2. It was true of both groups of patients that the survival rate of patients with and without lymph node involvement was significantly different. However, the survival rate of patients in stage T2 but without lymph node involvement was not significantly different as compared to that of patients in stage T1. CONCLUSION: For stage T1 stomach cancer, because of possible lymph node involvemnt, local mucosal excision of tumor is not recommended. For stage T2 stomach cancer without lymph node metastasis, it can be regarded as cancer still in its early stage when postoperative adjunct therapy is to be given.

Adult↗

PubMed1999

[Isolation and characterization of human prostate cancer cell subclones with different metastatic potential].

OBJECTIVE: To isolate and characterize cancer cell subclones with different metastatic potential from human metastatic prostate cancer cell line (PC-3M). METHODS: Using limited dilution, in vitro growth, Matrigel invasion assay, soft agar cloning and in vivo tumorigenicity and spontaneous metastasis assay in nude mice, were isolated and characterized four subclones with different metastatic potential. RESULTS: Four subclones derived from PC-3M were 1E8, 2E7, 2B6, 2B4. Each subclone exhibited a different metastatic potential when inoculated into nude mice. Among these subclones, 1E8 expressed as the highly metastatic phenotype, with 100% metastasis frequency 5 weeks after subcutaneous inoculation into nude mice, whereas 2B4 was not metastatic. In vitro 1E8 was found to be the most highly invasive cell line in Matrigel invasive assay (98 +/- 24) and had the most clones in soft agar cloning assay (265 +/- 39) while 2B4 was found to have the least invasive abilities (12 +/- 4) and the least clones (137 +/- 14). CONCLUSION: Successful establishment of these subclones with different metastatic potential may be valuable for further study on the molecular mechanisms of cancer metastasis and cloning of cancer metastasis-related genes.

Animals↗

PubMed1999

[Analysis of the vestiges of farm chemicals for Panax notoginseng].

The vestiges of farm chemicals in Panax notoginseng plants and medicinal materials from main production areas in Wenshan District was analyzed in this study. The result showed that the samples from the places contained hexachloro-cyclohexane and DDT. And the vestiges of hexachloro-cyclohexane was about 0.016-0.101 mg/kg, that of DDT was about 0.15-0.143 mg/kg. The content of Cu, Zn, Pb, Cd was lower than national standard of P. R. C.

China↗