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Biomedical subjects

Hui Li

Publications and source records attributed to Hui Li.

At least 127 records · Page 7Linked to original sources

[Serum organochlorines pesticides level of non-occupational exposure women and risk of breast cancer:a case-control study].

OBJECTIVE: To describe exposure level of organochlorines pesticides residues in non-occupational exposure population in China and testify the hypothesis that organochlorine pesticides exposure may be the risk factor to human breast cancer. METHODS: A case-control study based on community was designed. 90 new diagnostic breast cancer patients from the Second Hospital of Sichuan Province, and 136 health women from community, who settled down in the same district as case were enrolled. The risk factors of breast cancer were investigated by a questionnaire. GC-ECD was used to measure the serum level of Organochlorines pesticide residues. The adjusted odds rations (OR) of organochlorines pesticides residues to breast cancer were evaluated by logistic regression model. RESULTS: 8 organochlorines pesticide residues including p, p'-DDT, p, p'-DDE, o, p'-DDT, p, p'-DDD and alpha, beta, gamma, delta-HCHs (hexachlorocyclohexane) could be detected in serum of cases and controls. The detecting rates of beta-HCH, p, p'-DDE and p, p'-DDT respectively were 91.2%, 92.1% and 91.2%. There were no significant differences of serum level of organochlorines pesticides residues between cases and controls (P > 0.05). After adjusting confounding factors, serum p,p'-DDT, p,p'-DDD, and delta-HCH level were positively related to the risk of breast cancer (adjusted OR > 2, P < 0.05) . High serum p,p'-DDT,p,p'-DDD and beta-HCH level were positively correlated to premenopausal women (adjusted ORs respectively were 3.59, 5.70 and 3.06, P < 0.05). CONCLUSION: Organochlorines pesticides resides, including DDTs and HCHs, may increase women's risk of breast cancer, particularly in premenopausal women in China.

Adult↗

[Determination of trace lead in water samples and salt samples by graphite furnace atomic absorption spectrometry after cloud point extraction].

A method was developed for the determination of trace lead in water samples and salt samples by GFAAS after cloud point extraction. The parameters of extraction system such as pH, the concentrations of the extractant and the surfactant, and the time for cloud point extraction were optimized. Under the optimized conditions, the detection limits of lead were 0.000 5 microg x g(-1) for salt, and 0.01 microg x L(-1) for water, respectively. The proposed method was applied to the determination of lead in water samples and salt samples, and satisfactory results were obtained.

Lead↗

Regulating effects of novel CpG chitosan-nanoparticles on immune responses of mice to porcine paratyphoid vaccines.

OBJECTIVE: To study the regulating effects of a novel CpG oligodeoxynuleotide and the synergistic effect of chitosan-nanoparticles (CNP) with CpG on immune responses of mice, which were used to develop a novel immunoadjuvant to boost immune response to conventional vaccines. METHODS: A novel CpG ODN containing 11 CpG motifs was synthesized and its bioactivities to stimulate the proliferation of lymphocytes of pig in vitro were detected. Then it was entrapped with CNP prepared in our laboratory by the method of ionic cross linkage, and immunized Kunming mice were co-inoculated with paratyphoid vaccine. The peripheral blood was collected weekly from the tail vein of inoculated mice to detect the contents of IgG, IgA, IgM, and specific antibody against salmonella as well as the levels of interleukin-2 (IL2), IL-4, and IL-6 by SABC-ELISA assay. The numbers of leucocytes, monocytes, granuloytes, and lymphocytes were calculated separately using the routine method. The experimental mice were orally challenged with virulent salmonella 35 days after inoculation. RESULTS: This CpG ODN could remarkably provoke the proliferation of lymphocytes of pig in vitro in contrast with the control (P < 0.05). Compared with those of the control, immunoglobulins, including IgG, IgA, IgM, and specific antibodies to paratyphoid vaccine, increased significantly in sera from the CpG or CpG-CNP-vaccinated mice (P < 0.05). IL-2, IL-4, and IL-6 increased remarkably in sera from immunized mice (P < 0.05). The leucocytes, monocytes, granuloytes, and lymphocytes of the mice immunized with CpG or CpG-CNP were also increased in number (P < 0.05). After the challenge, these immunity values were elevated in the mice vaccinated with CpG or CpG-CNP. The immunized mice all survived, while the control mice fell ill with evident lesions with diffuse hemorrhage in stomach, small intestine, and peritoneum. CONCLUSIONS: CpG ODN entrapped with CNP is a promising effective immunoadjuvant for vaccination, which promotes humoral and cellular immune responses, enhances immunity and resistance against salmonella by co-administration with paratyphoid vaccine.

Adjuvants, Immunologic↗

[HPLC determination of acteoside in Radix Rehmanniae].

OBJECTIVE: To develop an HPLC method for the determination of acteoside in Radix Rehmanniae. METHOD: The chromatographic conditions were as follows: Polaris C18(4.6 mm x 250 mm, 5 microm) column, a mobile phase in gradient mode composed of acetonitrile 0.1% acetic acid solution, a flow rate of 1.0 mL x min(-1), and 334 nm as the detection wavelength. RESULT: Acteoside showed good linear relationship at the range of 10-500 microg x mL(-1) (r = 0.9990). The average recovery was 100.1%, RS D 3.7%. CONCLUSION: The proposed method promised to be applicable for the quality control of Radix Rehmanniae.

Chromatography, High Pressure Liquid↗

[Polymorphisms of the DNA repair genes XRCC1 and XPC: relationship to pancreatic cancer risk].

OBJECTIVE: To determine whether genetic polymorphisms in XRCC1 and XPC are associated with risk of pancreatic cancer. METHODS: A case-control study was conducted in 101 incident cases with pancreatic cancer and 337 controls (matched for age, sex and ethnicity) to investigate whether genetic polymorphisms in DNA repair genes XRCC1 (Arg194Trp and Arg399Gln) and XPC (an intronic biallelic poly (AT) insertion/deletion polymorphism, XPC-PAT) were associated with risk of pancreatic cancer. The odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated by unconditional logistic regression models and adjusted for potential confounding factors. RESULTS: There was a small, non-significant decrease in risk for pancreatic cancer in those carrying Gln/Gln genotype at XRCC1 Arg399Gln site (OR 0.64, 95% CI 0.21 - 1.66, P = 0.30) compared with those having Arg/Arg genotypes. And the XRCC1 Arg194Trp polymorphism was not significantly associated with risk of pancreatic cancer. For XPC-PAT polymorphism, 5.0% of cases and 13.4% of controls were homozygous for the variant allele (PAT+/+), resulting in an OR of 0.30 (95% CI 0.10 - 0.76, P = 0.02), which suggested that the PAT +/+ genotype might have protective effect against pancreatic carcinogenesis. CONCLUSIONS: This study suggest that XPC-PAT polymorphisms may contribute to the risk of pancreatic cancer in our study population.

Adult↗

[Sol-gel preparation of ultrathin nano-hydroxyapatite coating and its characterization].

Present study used dip-coating techniques to fabricate ultrathin nano-HA coating on titanium in organic sol-gel of Ca (NO3)2. 4H2O and PO(CH3)3 and inorganic sol-gel of Ca (NO3)2. 4H2O and (NH4)2HPO4. Scanning electron microscope (SEM) and grazing-incidence X-ray diffraction (XRD) were used to observe the morphology and distribution of crystallite size (D) and lattice strain (epsilon) of ultrathin nano-HA coating. After heated at 400 degrees C, the apatite structure of coatings on titanium began to appear. At heating temperature of 400 degrees C-600 degrees C, the effect of heating temperature on D and epsilon of both coatings was obvious. Precursor types significantly affected the particle diameters of nano-HA coatings, which were 25-40 nm for organic sol-gel and about 100 nm for inorganic sol. The thickness of ultrathin nano-HA coatings was 2.5 microm for organic sol-gel and 5 microm for inorganic sol and morphology of interfaces between coating and titanium was intact and homogenous.

Coated Materials, Biocompatible↗

[The effect of Xuezhikang on ventricular diastolic function in hypertension].

OBJECTIVE: To investigate whether statins have effect on diastolic function of both left and right ventricles in hypertensive patients. METHODS: This is a randomized, mono-blind, placebo-controlled study. 120 systemic hypertensive (HT) patients with normal or slightly elevated cholesterol were randomized to placebo or Xuezhikang (1200 mg/d) for 24 weeks. Extended-release nifedipine was administrated to the HT patients. 30 healthy volunteers served as controls. Plasma were obtained at baseline and 24 weeks after Xuezhikang therapy. Cholesterol and carboxy-terminal peptide of procollagen type I (PIP) were measured. Early diastolic velocity (Em) and late diastolic velocity (Am) were obtained from right atrioventricular ring and left atrioventricular ring with pulsed wave tissue Doppler imaging. RESULTS: The levels of plasma PIP were higher in HT patients. After 24 weeks, the levels of plasma LDL-C, TC and PIP were significantly lower in Xuezhikang group than those in placebo group; Systolic and diastolic pressure were decreased both in placebo group and Xuezhikang group meanwhile pulse pressure was decreased and Em/Am ratio at left atrioventricular ring was higher in Xuezhikang group as compared with those in placebo group. CONCLUSION: In systemic hypertensive patients, Xuezhikang exerts a beneficial effect on diastolic function of left ventricule via controlling blood pressure, lowering blood lipid and inhibiting myocardial fibrosis.

Aged↗

Annular arrangement and collaborative actions of four domains of protein-disulfide isomerase: a small angle X-ray scattering study in solution.

We presented for the first time a small angle x-ray scattering study of intact protein-disulfide isomerase (PDI) in solution. The restored model revealed that PDI is a short and roughly elliptical cylinder with a molecular mass of 69 kDa and dimensions of 105 x 65 x 40 A, and the four thioredoxin-fold domains in the order a-b-b'-a' are arranged in an annular fashion. Atomic force microscope imaging also supported the finding that PDI appears as an approximately flat elliptical cylinder. A PDI species with apparent molecular mass of 116 kDa measured by using size-exclusion chromatography, previously assumed to be a dimer, was determined to exist mainly as a monomer by using analytical ultracentrifugation. The C-terminal fragment 441-491 contributed to the anomalous molecular mass determination of PDI by size-exclusion chromatography. The annular model of PDI accounted for the cooperative properties of the four domains in both the isomerase and chaperone functions of PDI.

Crystallography, X-Ray↗

Contractile ring-independent localization of DdINCENP, a protein important for spindle stability and cytokinesis.

Dictyostelium DdINCENP is a chromosomal passenger protein associated with centromeres, the spindle midzone, and poles during mitosis and the cleavage furrow during cytokinesis. Disruption of the single DdINCENP gene revealed important roles for this protein in mitosis and cytokinesis. DdINCENP null cells lack a robust spindle midzone and are hypersensitive to microtubule-depolymerizing drugs, suggesting that their spindles may not be stable. Furthermore DdCP224, a protein homologous to the microtubule-stabilizing protein TOGp/XMAP215, was absent from the spindle midzone of DdINCENP null cells. Overexpression of DdCP224 rescued the weak spindle midzone defect of DdINCENP null cells. Although not required for the localization of the myosin II contractile ring and subsequent formation of a cleavage furrow, DdINCENP is important for the abscission of daughter cells at the end of cytokinesis. Finally, we show that the localization of DdINCENP at the cleavage furrow is modulated by myosin II but it occurs by a mechanism different from that controlling the formation of the contractile ring.

Animals↗

Very fast empirical prediction and rationalization of protein pKa values.

A very fast empirical method is presented for structure-based protein pKa prediction and rationalization. The desolvation effects and intra-protein interactions, which cause variations in pKa values of protein ionizable groups, are empirically related to the positions and chemical nature of the groups proximate to the pKa sites. A computer program is written to automatically predict pKa values based on these empirical relationships within a couple of seconds. Unusual pKa values at buried active sites, which are among the most interesting protein pKa values, are predicted very well with the empirical method. A test on 233 carboxyl, 12 cysteine, 45 histidine, and 24 lysine pKa values in various proteins shows a root-mean-square deviation (RMSD) of 0.89 from experimental values. Removal of the 29 pKa values that are upper or lower limits results in an RMSD = 0.79 for the remaining 285 pKa values.

Amino Acids↗

Spectroscopic study of carbaryl sorption on smectite from aqueous suspension.

Sorption of carbaryl (1-naphthyl-N-methyl-carbamate) from aqueous suspension to smectite was studied using Fourier transform infrared (FTIR), high-performance liquid chromatography (HPLC) (for batch sorption), and quantum chemical methods. The amount of carbaryl sorbed was strongly dependent on the surface-charge density of the smectite with more sorption occurring on the two "low" surface-charge density smectites (SHCa-1 and SWy-2) compared to that of the high surface-charge SAz-1 smectite. In addition, the amount of carbaryl sorbed was strongly dependent on the nature of the exchangeable cation and followed the order of Ba approximately Cs approximately Ca > Mg approximately K > Na approximately Li for SWy-2. A similartrend was found for hectorite (SHCa-1) of Cs > Ba > Ca > K approximately Mg > Na approximately Li. Using the shift of the carbonyl stretching band as an indicator of the strength of interaction between carbaryl and the exchangeable cation, the observed order was Mg > Ca > Ba approximately K > Na > Cs. The position of the carbonyl stretching band shifted to lower wavenumbers with increasing ionic potential of the exchangeable cation. Density functional theory predicted a cation-induced lengthening of the C=O bond, resulting from the carbonyl group interacting directly with the exchangeable cation in support of the spectroscopic observations. Further evidence was provided by a concomitant shift in the opposite direction by several vibrational bands in the 1355-1375 cm(-1) region assigned to stretching bands of the carbamate N-Ccarbonyl and Oether-Ccarbonyl bonds. These data indicate that carbaryl sorption is due, in part, to site-specific interactions between the carbamate functional group and exchangeable cations, as evidenced by the FTIR data. However, these data suggest that hydrophobic interactions also contribute to the overall amount of carbaryl sorbed. For example, the FTIR data indicated thatthe weakest interaction occurred when Cs+ was the exchangeable cation. In contrast, the highest amount of carbaryl sorption was observed on Cs-exchanged smectite. Of all the cations studied, Cs has the lowest enthalpy of hydration. It is suggested that this low hydration energy provides the carbaryl with greater access to the hydrophobic regions of the siloxane surface.

Carbaryl↗

Rerouting lipoprotein nanoparticles to selected alternate receptors for the targeted delivery of cancer diagnostic and therapeutic agents.

We report that a lipoprotein-based nanoplatform generated by conjugating tumor-homing molecules to the protein components of naturally occurring lipoproteins reroutes them from their normal lipoprotein receptors to other selected cancer-associated receptors. Multiple copies of these targeting moieties may be attached to the same nanoparticle, or a variety of different targeting moieties can be attached. Such a diverse set of tumor-homing molecules could be used to create a variety of conjugated lipoproteins as multifunctional, biocompatible nanoplatforms with a broad application to both cancer imaging and treatment. The same principle can be applied to imaging and treatment of other diseases and for monitoring specific tissues. To validate this concept, we prepared a low-density lipoprotein (LDL)-based folate receptor (FR)-targeted agent by conjugating folic acid to the Lys residues of the apolipoprotein B (apoB)-100 protein. To demonstrate the ability of the lipoprotein-based nanoplatform to deliver surface-loaded and core-loaded payloads, the particles were labeled either with the optical reporter 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine that was intercalated in the phospholipid monolayer or with the lipophilic photodynamic therapy agent, tetra-t-butyl-silicon phthalocyanine bisoleate, that was reconstituted into the lipid core. Cellular localization of the labeled LDL was monitored by confocal microscopy and flow cytometry in FR-overexpressing KB cells, in FR-nonexpressing CHO and HT-1080 cells, and in LDL receptor-overexpressing HepG2 cells. These studies demonstrate that the folic acid conjugation to the Lys side-chain amino groups blocks binding to the normal LDL receptor and reroutes the resulting conjugate to cancer cells through their FRs.

Animals↗

[Dendritic cells reduce the number and function of CD4+CD25+ cells in cytokine-induced killer cells].

OBJECTIVE: To investigate the influence of dendritic cells (DCs) on the prevalence and function of regulatory T cells (Tregs) in cytokine induced killer (CIK) cells. METHODS: The blood samples of 20 patients with solid tumors were collected. The peripheral mononuclear cells (PBMCs) were isolated. CIK cells were added into the culture fluid without CD(4)(+)CD(25)(+)T cells (CIK-Treg(del) cells) and the culture fluid of regular PBMCs respectively, and the proliferation and cytotoxicity of the CIK cells were detected by BrdU method and with the cells of human lung carcinoma, breast carcinoma, colon carcinoma, and lymphoma as target cells respectively. CD(4)(+)CD(25)(+)T cells were added into another culture fluid of CIK-Treg(del) cells at the proportions of 20:1, 10:1, and 5:1 respectively, then the proliferation and cytotoxicity of the CIK cells were detected as described above. Flow cytometry was used to detect the surface markers of CIK cells. To identify the influence of DCs on the anti-tumor activity of CIK, PBMCs were isolated from the patients with solid tumor to culture the DCs and CIK cells. Dendritic cells were harvested on day 7 and co-cultured with the CIK cells (DC+CIK cells). The frequency of Tregs in CIK was determined by flow cytometry. The cytotoxicity was examined by LDH assay. The levels of TGF-beta, IL-10, IFN-gamma, IL-2, and IL-6 were analyzed by ELISA. RESULTS: The rates of the main effector cells in CIK cells (CD(3)(+)CD(56)(+) cells) were 17% +/- 5% and 28% +/- 5% in the regular CIK cells and CIK-Treg(del) cells respectively. LDH method showed that the cytotoxicity towards tumor cells of the CIK-Treg(del) cells The rates of the main effector cells in CIK cells (CD(3)(+)CD(56)(+) cells) were 17% +/- 5% and 28% +/- 5% in the regular CIK cells and CIK-Treg(del) cells respectively. LDH method showed that the cytotoxicity towards tumor cells of the CIK-Treg(del) cells was higher than that of the regular CIK cells (P < 0.05), however, after the addition of selected cells, the cytotoxicity of the CIK-Treg(del) cells decreased. Flow cytometry showed that the proportions of CD(4)(+)CD(25)(+) Treg cells in the CIK cells and DC-CIK cells were 13% +/- 5% and 10% +/- 4% respectively (t = 3.977, P = 0.001). After the DC induction the cytotoxicity of CIK cells was significantly higher than that of the regular CIK cells. ELISA showed that after DC induction the levels of TGF-beta and IL-10 of the DC+CIK group were significantly lower than those of the regular CIK cells (t = 2.136, P = 0.046; and t = 2.965, P = 0.008), and the level of IFN-gamma was significantly higher in the DC+CIK group (t = 2.220, P = 0.039). CONCLUSION: CD(4)(+)CD(25)(+) regulatory T cells inhibit the anti-tumor activity of CIK cells. The interaction between CIK cells and DCs is sufficient for the blockage of the properties of regulatory T cells. CIK cells have the desirable properties for immunotherapy approaches, especially after co-culture with DCs.

CD4-Positive T-Lymphocytes↗

Control of slow myosin heavy chain 2 gene expression by glycogen synthase kinase activity in skeletal muscle fibers.

Skeletal muscle fiber type and expression of slow muscle fiber type specific genes are regulated by fiber type specific cell signaling events initiated by innervation. In avian muscle fibers, expression of the slow myosin heavy chain 2 (MyHC2) gene defines fast versus slow muscle fiber types, and its expression is dependent on the transcription factor, nuclear factor of activated T cells (NFAT). Glycogen synthase kinase 3 (GSK3) phosphorylates NFAT and inhibits its transactivating potential. We report here that expression of the slow MyHC2 gene is dependent on GSK3 activity. Inhibition of GSK3 activity by SB216763 or LiCl induced expression of the slow MyHC2 gene in non-innervated medial adductor (MA) muscle fibers and in innervated fast pectoralis major (PM) muscle fibers. Innervation of MA and PM muscle fibers did not significantly alter GSK3 activity. However, inhibition of GSK3 activity increased NFAT-mediated transcriptional activity, required for full activation of the slow MyHC2 gene, and overexpression of GSK3 reduced NFAT-mediated transcription. Inhibition of GSK3 activity was sufficient to induce slow MyHC2 gene expression in non-innervated MA muscle fibers but not in non-innervated PM muscle fibers, suggesting that fiber type specific mechanisms differentially regulate slow MyHC2 gene expression in innervated muscle fibers.

Animals↗

Hydroxyl-radical-dependent DNA damage by ambient particulate matter from contrasting sampling locations.

Exposure to ambient particulate matter (PM) has been reported to be associated with increased respiratory, cardiovascular, and malignant lung disease. Previously we have shown that PM can induce oxidative DNA damage in A549 human lung epithelial cells. The aims of the present study were to investigate the variability of the DNA-damaging properties of PM sampled at different locations and times and to relate the observed effects to the hydroxyl-radical (OH)-generating activities of these samples. Weekly samples of coarse (10-2.5 microm) and fine (<2.5 microm) PM from four sites (Nordrheim Westfalen, Germany) were analyzed for hydrogen-peroxide-dependent OH formation using electron paramagnetic resonance and formation of 8-hydroxydeoxyguanosine (8-OHdG) in calf thymus DNA using an immuno-dot-blot assay. DNA strand breakage by fine PM in A549 human lung epithelial cells was quantified using the alkaline comet assay. Both PM size distribution fractions elicited OH generation and 8-OHdG formations in calf thymus DNA. Significantly higher OH generation was observed for PM sampled at urban/industrial locations and for coarse PM. Samples of fine PM also caused DNA strand breakage in A549 cells and this damage could be prevented using the hydroxyl-radical scavengers 5,5-dimethyl-1-pyrroline-N-oxide and dimethyl sulfoxide. The observed DNA strand breakage appeared to correlate with the hydroxyl-radical-generating capacities of the PM samples but with different profiles for rural versus urban/industrial samples. In conclusion, when considered at equal mass, OH formation of PM shows considerable variability with regard to the sampling location and time and is correlated with its ability to cause DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗

The effect of endogenous formaldehyde on the rat aorta endothelial cells.

Previous studies have demonstrated endogenous formaldehyde (FA) may be involved in endothelial damage, and may be a potential factor of vulnerability of atherosclerosis. However, the mechanism has not been characterized. The present studies examined DNA-protein cross-links (DPC) formation in rat aorta endothelial cells (RAECs) treated with formaldehyde, hydrogen peroxide (H2O2), or formaldehyde with equal molar concentration of H2O2, which is produced with formaldehyde in the body at the same time. Using a K+/SDS precipitation assay for DPC determination, concentration-dependent increases in DPC formation were observed 1.5 h after treatment of RAECs with 0.01-2mM FA, H2O2, or FA with equal molar concentration of H2O2. Time-dependent increases in DPC formation were also observed at 0.5-4 h time point after treatment of RAECs with 0.05 and 0.1mM FA, or 0.1mM FA with H2O2. The DPC levels reduced after treatment with FA and equal molar concentration of H2O2, compared with treatment with FA alone. FA may be less cytotoxic, as FA alone did not affect the cell viability even treating for 4h, until the treatment concentration reached 2mM. However, H2O2, and FA with H2O2 induced significant decreases of cell viability. These studies suggest that FA and H2O2 may injure endothelial cells synergistically, and low concentration of FA (0.05-0.1) may contribute to the endothelial injury in the body during aging.

Animals↗

[Clinical analysis of operation combined chemotherapy for stage IIIa non-small cell lung cancer].

OBJECTIVE: To study the therapeutic result of operation combined chemotherapy for stage IIIa non-small cell lung cancer. METHODS: From January 2000 to December 2003, the data of 83 cases with stage IIIa non-small cell lung cancer undergoing operation combined chemotherapy and 33 cases with stage IIIa non-small cell lung cancer undergoing non-operative therapy were retrospectively analyzed. The median survival time and the 1-, 2-, 3- year survival rates of the two groups were compared by the Kaplan-Meier method. RESULTS: The median survival time of the operation group was 20.3 months, and the 1-, 2-, 3- year survival rates were 85%, 70%, and 35% respectively. The median survival time of the non-operation group was 14.5 months and the 1-, 2-, 3- year survival rates were 75%, 33%, and 15% respectively. CONCLUSION: The therapeutic result of the operation combined chemotherapy for the stage IIIa non-small cell lung cancer is better than that of the non-operative therapy obviously.

Adult↗