Improving the experience of birth in poor communities.
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Biomedical subjects
Publications and source records attributed to Qian Xu.
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Myxococcus xanthus fibril exopolysaccharide (EPS), essential for the social gliding motility and development of this bacterium, is regulated by the Dif chemotaxis-like pathway. DifA, an MCP homolog, is proposed to mediate signal input to the Dif pathway. However, DifA lacks a prominent periplasmic domain, which in classical chemoreceptors is responsible for signal perception and for initiating transmembrane signaling. To investigate the signaling properties of DifA, we constructed a NarX-DifA (NafA) chimera from the sensory module of Escherichia coli NarX and the signaling module of M. xanthus DifA. We report here the first functional chimeric signal transducer constructed using genes from organisms in two different phylogenetic subdivisions. When expressed in M. xanthus, NafA restored fruiting body formation, EPS production, and S-motility to difA mutants in the presence of nitrate. Studies with various double mutants indicate that NafA requires the downstream Dif proteins to function. We propose that signal inputs to the Dif pathway and transmembrane signaling by DifA are essential for the regulation of EPS production in M. xanthus. Despite the apparent structural differences, DifA appears to share similar transmembrane signaling mechanisms with enteric sensor kinases and chemoreceptors.
STUDY OBJECTIVES: To examine the unique impact of financial difficulties as measured by a lack of money for basic needs on the occurrence of health problems between the ages of 17 and 29 months, controlling for mother's level of education and neonatal health problems. DESIGN AND PARTICIPANTS: Analyses were performed on the 29 month data of the Quebec longitudinal study of child development. This longitudinal study followed up a birth cohort annually. Interviews were conducted in the home with the mother in 98.8% of cases. This information was supplemented with data from birth records. At 29 months, the response rate was 94.2% of the initial sample (n = 1946). The main outcome measures were mothers' report of acute health problems, asthma episodes, and hospitalisation as well as growth delay and a composite index of health problems (acute problems, asthma attack, growth delay). MAIN RESULTS: Children raised in a family experiencing a serious lack of money for basic needs during the preceding year were more likely to be reported by their mothers as presenting acute health problems, a growth delay, two or more health problems, and to have been hospitalised for the first time within the past few months as compared with babies living in a family not experiencing a lack of money for basic needs regardless of the mother's level of education and of neonatal health problems. CONCLUSION: Financial difficulties as measured by a lack of money for basic needs have a significant and unique impact on toddlers' health.
BACKGROUND & OBJECTIVE: Chemokine receptors express on many tumor cells, and closely correlate with migration and metastasis of tumor cells. This study was to investigate expressions of chemokine(C-X-C) receptor 4 (CXCR4) and chemokine (C-X-C motif) ligand 12 (CXCL12) in human ovarian epithelial tumor cells, and their effects on migration of tumor cells. METHODS: Expression of CXCR4 mRNA and protein in 15 specimens of epithelial ovarian cancer tissue, ovarian cancer cell line CAOV3, endothelial cell line HUVEC, and 10 specimens of normal ovary tissue were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot. Expression of CXCL12 mRNA in retroperitoneal lymph nodes, and smooth muscle of fallopian tube from the same 15 epithelial ovarian cancer patients was tested by RT-PCR, quantity of CXCL12 in ascites of 15 patients was assayed using ELISA. Boyden Transwells was used to analyze effects of CXCL12, and cancerous ascites on chemotaxis of CAOV3, and HUVEC cells. RESULTS: (1) Expression levels of CXCR4 mRNA in ovary cancer tissues, CAOV3 cells, and HUVEC cells were 2.30+/-1.12, 1.89+/-1.20, and 1.68+/-1.11, respectively; those of CXCR4 protein were 1.35+/-0.14, 1.86+/-0.34, and 1.96+/-0.23, respectively; CXCR4 mRNA and protein can't be detected in normal ovarian tissues. (2) In 15 ovarian cancer patients, concentrations of CXCL12 in ascites were 632-9 326 pg/ml, and CXCL12 mRNA level in retroperitoneal lymph nodes was 1.14+/-0.87, CXCL12 mRNA can't be detected in smooth muscle of fallopian tube. (3) Recombinant human CXCL12 induced migration of CAOV3, and HUVEC cells, the chemotactic indices (CI) were 3.9+/-1.2, and 4.1+/-1.6, significantly higher than those of control (1.0+/-0.4, and 1.1+/-0.7) (P<0.05)u cancerous ascites induced migration of CAOV3 cells with CI of 1.9+/-0.8, significantly higher than that of control (P<0.05). CONCLUSION: CXCR4 and CXCL12 may play roles in metastasis of epithelial ovarian cancer by promoting migration of tumor cells and endothelial cells.
OBJECTIVE: To investigate the expression of human telomerase reverse transcriptase (hTERT) mRNA and protein in cervix cancer, cervical intraepithelial neoplasia (CIN) and normal cervix. METHODS: Expression of hTERT mRNA and the other two subunits of telomerase, human telomerase RNA component (hTR), human telomerase-associated protein (hTP1) was determined by RT-PCR in 3 cervix cancer cell lines, 2 diploid cell lines, 38 cases of cervix cancer, 16 cases of CIN and 20 cases of normal cervix. Telomerase activity was also examined by telomeric repeat amplification protocol enzyme-linked immunosorbent assay (TRAP-ELISA). Expression of hTERT protein was detected in all the cell lines and 101 cases of paraffinized cervix tissue sections. RESULTS: hTERT mRNA expression was detected in all of the three cervix cancer cell lines, 81.6% of cervix cancer, 37.5% of CIN, 5.0% of normal cervix, while in neither of the two diploid cell lines. The other two subunits of telomerase were prevalently expressed in all of the cell lines and most cervix tissues. There was a strong correlation between hTERT mRNA expression and telomerase activity. Immunostaining also revealed that hTERT protein was expressed in all three cervix cancer cell lines, 65.5% of cervix cancer, 28.0% of CIN and 4.8% of normal cervix. CONCLUSION: Up-regulation of hTERT may play an important role in the development of CIN and cervix cancer, hTERT could be used as an early diagnostic biomarker for cervix cancer.
CD44+ CD29+ and CD44- CD29+ bone marrow mesenchymal stem cells (BMSCs) were isolated from bone marrow of BALB/C male donor mouse by adherence selecting in DMEM media with low glucose and 20% fetal bovine serum. Then P5 cells were injected into the liver remnants of hepatectomined female mouse. Simultaneous assays were performed on the injected liver lobe and other liver lobe for detecting the Y-chromosome by fluorescence in situ hybridization and for defecting the albumin or cytokeratin 18 (CK18) by fluorescence immunoassays. Both Y chromosome and albumin (or CK18) positive cell could be detected at 5 days and 14 days after transplantation. At 14 days after transplantation, the liver weight in transplanted mouse was higher than that in model mouse. These results suggest that BMSCs could be induced to differentiate into hepatocytes and participate in the regeneration of liver.
A high performance liquid chromatographic method with fluorescence detection for the determination of chloramphenicol (CAP) residues in milk was developed. Although CAP itself is non-fluorescent the aromatic nitro group of CAP could be reduced to aromatic primary amino group and fluorescamine can be used as a selective reagent for primary amines. Therefore, the CAP was derivatized with fluorescamine prior to injection in this project. The HPLC method was performed on a Diamond C18 column (250 mm x 4.6 mm i. d., 4.0 microm) with the mobile phase composed of sodium acetate buffer (0.02 mol/L, pH 6.0) -acetonitrile-tetrahydrofuran (76: 16: 8, v/v/v). The flow rate of the mobile phase was set at 1.0 mL/min, and the column was maintained at 40 degrees C. Analytes were detected by a fluorescence detector at 410 nm excitation and 508 nm emission wavelength. The standard curve was linear in the range from 0.4 microg/L to 800 microg/L. The limit of detection (LOD) was 0.2 microg/L, and the limit of quantitation (LOQ) was 0.4 microg/L. Overall recoveries were between 66.6% and 92.8% with relative standard deviations between 4.5% and 9.4%. The procedure provides a rapid, reliable and sensitive method for the determination of CAP in milk.
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AIM: To investigate the early diagnostic methods of bacterial and fungal infection in patients with chronic cholestatic hepatitis B. METHODS: One hundred and one adult in-patients with chronic hepatitis B were studied and divided into 3 groups: direct bilirubin (DBil)/total bilirubin (TBil) > or = 0.5, without bacterial and fungal infection (group A, n=38); DBil/TBil <0.5, without bacterial and fungal infection (group B, n=23); DBil/TBil> or = 0.5, with bacterial or fungal infection (group C, n=40). The serum biochemical index and pulse rate were analyzed. RESULTS: Level of TBil, DBil, alkaline phosphatase (ALP) and DBil/ALP in group A increased compared with that in group B. The level of ALP in group C decreased compared with that in group A, whereas the level of TBil, DBil and DBil/ALP increased (ALP: 156+/-43, 199+/-68, respectively, P<0.05; TBil: 370+/-227, 220+/-206, respectively, P<0.01; DBil: 214+/-143, 146+/-136, respectively, P<0.01; DBil/ALP: 1.65+/-1.05, 0.78+/-0.70, respectively, P<0.001). The level of DBil and infection affected DBil/ALP. Independent of the effect of DBil, infection caused DBil/ALP to rise (P<0.05). The pulse rate in group A decreased compared with that in group B (63.7+/-6.4, 77.7+/-11.4, respectively, P<0.001), and the pulse rate in group C increased compared with that in group A (81.2+/-12.2, 63.7+/-6.4, respectively, P<0.001). The equation (infection=0.218 pusle rate +1.064 DBil/ALP -16.361), with total accuracy of 85.5%, was obtained from stepwise logistic regression. Pulse rate (> or =80/min) and DBil/ALP (> or =1.0) were used to screen infection. The sensitivity was 62.5% and 64.7% respectively, and the specificity was 100% and 82.8% respectively. CONCLUSION: Bacterial and fungal infection deteriorate jaundice and increase pulse rate, decrease serum ALP and increase DBil/ALP. Pulse rate, DBil/ALP and the equation (infection=0.218 pusle rate+1.064 DBil/ALP-16.361) are helpful to early diagnosis of bacterial and fungal infection in patients with chronic cholestatic hepatitis B.
OBJECTIVE: To explore heat shock protein 70 (HSP70) expression of A549 cells and its role in DNA damage caused by benzo(a)pyrene (BaP). METHODS: Human adenocarcinoma A549 cells were cultured in vitro, exposed by different concentrations of BaP (0, 1.25, 2.50, 5.00, 10.00 micro mol/L) for 6 hours, or 10 micro mol/L of BaP for different time (0, 4, 8, 12, 16, 24 and 48 h). Then HSP70 expression and DNA damage were detected using Western-blot and single cell gel electrophoresis (SCGE) assay respectively, and the relationship between HSP70 expression and DNA damage was further analyzed. RESULTS: The integral optical densities of HSP70 in A549 cells treated with 1.25, 2.50, 5.00 and 10.00 micro mol/L BaP for 6 h (49.63 +/- 1.30, 45.72 +/- 1.03, 40.53 +/- 0.95, 37.50 +/- 1.20 respectively) were lower than that of the control cells (59.43 +/- 1.17) (P < 0.05). When A549 cells were exposed to 10 micro mol/L BaP for 4, 8, 12, 16 h, the integral optical densities of HSP70 were 33.33 +/- 0.80, 29.23 +/- 0.91, 12.51 +/- 0.96, 9.50 +/- 1.25 respectively, and there was an increasing tendency of the expression of HSP70 for 24 - 48 h (20.06 +/- 1.38, 24.51 +/- 1.39), however, all were different from that in control group (56.59 +/- 0.85) (P < 0.05). DNA damage scores in 10(6) A549 cells treated with 2.50, 5.00 and 10.00 micro mol/L BaP for 6 h (23,718 +/- 2,938, 30,128 +/- 2,937, 44,231 +/- 3,846) were significantly higher than that of the control cell (9,615 +/- 1,923) (P < 0.05). When A549 cells were exposed to 10 micro mol/L BaP for 4, 8, 12, 16, 24, 48 h, DNA damage scores (16,667 +/- 4,003, 38,461 +/- 1,924, 5,615 +/- 3,847, 76,282 +/- 2,937, 7,513 +/- 1,110 and 58,975 +/- 9,487) were also higher than that of control group (P < 0.05). There was a negative correlation between DNA damage and the expression of HSP70 when A549 cells were exposed to different concentrations of BaP. CONCLUSION: HSP70 might enhance intracellular defenses against DNA damage induced by BaP.
OBJECTIVE: To investigate the effects of mitogen activated protein kinase (MAPK) signal transduction pathways on heat shock protein 70 (HSP70) gene expression in endothelial cells exposed to benzo(a)pryene (BaP). METHODS: Porcine aortic endothelial cells were pre-treated or by PD98059 (10 micro mol/L) or SB203580 (20 micro mol/L) for 1 hour, then treated with different concentrations of BaP (0, 0.1, 0.5, 1.0, 5.0 and 10.0 micro mol/L) for 24 hours respectively;Expression levels of three phosphorylated MAPKs [extracellular signal regulated protein kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38] and HSP70 were determined by Western-blot. RESULTS: The three phosphorylated MAPKs expressional levels especially p-ERK1 had different extents of changes with dose-response relationship under BaP exposure. BaP inhibited the expression of HSP70, which significantly decreased in medium and high dose group (>or= 1.0 micro mol/L) but did not decrease in control group (P < 0.05). Although the inhibitor of ERK (PD98059) could partly weaken the inhibited effects of BaP on HSP70 expression, HSP70 expression levels of endothelial cells pre-treated with PD98059 were still significantly lower than that of control cells (P < 0.05). CONCLUSION: ERK1 pathway might play some roles in HSP70 gene expression in endothelial cells exposed to BaP, and other unknown signal pathways might also have some effects on this process.
OBJECTIVE: To study the mechanism of topotecan (TPT) resistance in ovarian cancer cell line. METHODS: A TPT-resistant ovarian cancer cell line A2780/TPT established in this laboratory was used in this study. Intracellular rhodamine fluorescence intensity of the TPT-resistant cells and parental cells were measured by flow cytometry. The gene expression of membrane protein transporter such as transporter P-glycoprotein (P-gp), multidrug resistance associated protein (MRP), breast cancer resistance protein (BCRP) was evaluated by RT-PCR. The antisense-phosphorothioate oligonucleotide (ASODN) including a translation initiation site of BCRP mRNA was transferred into resistant cells by liposome. RESULTS: Intracellular rhodamine fluorescence intensity of the resistant cells was 31.19% of that in the parental cells (P < 0.01). No expression of P-gp was demonstrated, and that of MRP was very weak in the TPT-resistant cells (relative expression value = 0.057). BCRP was overexpressed in the TPT-resistant cells (relative expression = 0.66), but not in the parental cells. Transfer of ASODN into resistant cells resulted in a 59.42% reduction of BCRP gene expression (P < 0.05) and an obviously increased intracellular rhodamine fluorescence intensity from 5.42 to 16.63 (P < 0.05). CONCLUSION: The overexpression of BCRP which mediated drug efflux may play an important role in the induction of TPT-resistance in ovarian cancer.
OBJECTIVE: To study the pattern of polymorphism expression of heat-shock protein 70 (HSP70) family in A549 cell line treated with different concentrations of benzo(a)pyrene (BaP) and its probable biological effect. METHOD: Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) was used for the HSP70 expression analysis. RESULTS: 2D-PAGE showed that when A549 cells were exposed to different concentrations of BaP (0.1, 1.0, 5.0, 10.0 micromol/L) for 24, 48 h respectively, the HSP72 in A549 gradually declined as BaP concentrations increased [the integral OD (IOD)] for 24 h were: 150.36 +/- 26.03, 98.57 +/- 13.34, 64.92 +/- 15.03, 34.65 +/- 19.10, 32.92 +/- 18.71 respectively, for 48 h: 126.85 +/- 17.41, 106.19 +/- 15.32, 73.64 +/- 21.02, 35.18 +/- 11.95, 16.27 +/- 9.35 respectively), while the IOD of HSP73 did not show any remarkable change (24 h: 102.29 +/- 21.24, 87.71 +/- 18.70, 71.19 +/- 14.08, 71.87 +/- 15.16, 72.78 +/- 17.31 respectively; 48 h: 86.66 +/- 16.86, 75.67 +/- 10.61, 66.83 +/- 12.63, 67.29 +/- 10.26, 91.37 +/- 13.68 respectively). CONCLUSION: BaP can inhibit HSP72 expression and with certain dose-effect relationship, but cannot affect HSP73 expression.
BACKGROUND: Few population-based studies have analyzed the link between poverty and infant morbidity. In this study, we wanted to determine whether inadequate income itself has an impact on infant health. METHODS: We interviewed 2223 mothers of 5-month-old children participating in the 1998 phase of the Quebec Longitudinal Study of Child Development to determine their infant's health and the sociodemographic characteristics of the household (including household income, breast-feeding and the smoking habits of the mother). Data on the health of the infants at birth were taken from medical records. We examined the effects of household income using Statistics Canada definitions of sufficient (above the low-income threshold), moderately inadequate (between 60% and 99% of the low-income threshold) and inadequate (below 60% of the low-income threshold) income on the mother's assessment of her child's overall health, her report of her infant's chronic health problems and her report of the number of times, if any, her child had been admitted to hospital since birth. In the analysis, we controlled for factors known to affect infant health: infant characteristics and neonatal health problems, the mother's level of education, the presence or absence of a partner, the duration of breast-feeding and the mother's smoking status. RESULTS: Compared with infants in households with sufficient incomes, those in households with lower incomes were more likely to be judged by their mothers to be in less than excellent health (moderately inadequate incomes: adjusted odds ratio [OR] 1.5, 95% confidence interval [CI] 1.1-2.1; very inadequate incomes: adjusted OR 1.8, 95% CI 1.3-2.6). Infants in households with moderately inadequate incomes were more likely to have been admitted to hospital (adjusted OR 1.8, 95% CI 1.2-2.6) than those in households with sufficient incomes, but the same was not true of infants in households with very inadequate incomes (adjusted OR 0.7, 95% CI 0.4-1.2). Household income did not significantly affect the likelihood of an infant having chronic health problems. INTERPRETATION: Less than sufficient household incomes are associated with poorer overall health and higher hospital admission rates among infants in the first 5 months of life, even after adjustment for factors known to affect infant health, including the mother's level of education.
Myosin V is an unconventional myosin that transports cargo such as vesicles, melanosomes, or mRNA on actin filaments. It is a two-headed myosin with an unusually long neck that has six IQ motifs complexed with calmodulin. In vitro studies have shown that myosin V moves processively on actin, taking multiple 36-nm steps that coincide with the helical repeat of actin. This allows the molecule to "walk" across the top of an actin filament, a feature necessary for moving large vesicles along an actin filament bound to the cytoskeleton. The extended neck length of the two heads is thought to be critical for taking 36-nm steps for processive movements. To test this hypothesis we have expressed myosin V heavy meromyosin-like fragments containing 6IQ motifs, as well as ones that shorten (2IQ, 4IQ) or lengthen (8IQ) the neck region or alter the spacing between 3rd and 4th IQ motifs. The step size was proportional to neck length for the 2IQ, 4IQ, 6IQ, and 8IQ molecules, but the molecule with the altered spacing took shorter than expected steps. Total internal reflection fluorescence microscopy was used to determine whether the heavy meromyosin IQ molecules were capable of processive movements on actin. At saturating ATP concentrations, all molecules except for the 2IQ mutant moved processively on actin. When the ATP concentration was lowered to 10 microm or less, the 2IQ mutant demonstrated some processive movements but with reduced run lengths compared with the other mutants. Its weak processivity was also confirmed by actin landing assays.
In order to investigate the relationship between proliferative activities and heat stress protein 70(HSP70) expression of porcine aortic endothelial cells(ECs) treated by benzo(a) pryene in vitro, porcine aortic endothelial cells were cultured in vitro, treated by different concentration of BaP(0, 0.5, 1, 10, 20 mumol/L) for 24 hours. Then, the proliferative activities and HSP70 expression of endothelial cells were determined by MTT and Western-blot respectively. The results showed that along with the rise of concentration of BaP, proliferative activities of porcine aortic endothelial cells decreased. There are not significantly difference of expression of HSP70 between and control and low-exposed cultures(0.5 mumol/L), but decreased at intermedieate and high concentration(1, 10, 20 mumol/L). It was suggested that BaP restrained proliferative activities of porcine aortic endothelial cells, which may be related to the inhibition of HSP70 expression by BaP.
OBJECTIVE: To study the role of T lymphoma invasion/metastasis gene 1 (Tiam1) and protein in ovarian tumor cells. METHODS: Expressions of Tiam1 mRNA, Rac1 mRNA, and Tiam1 protein in four ovarian tumor cells A2780, Caov3, Skov3, and SW626 were studied by using RT-PCR and Western blot, respectively. The cell migration ability was analyzed by in vitro invasion assay. RESULTS: Expressions of Tiam1 mRNA and protein, as well as Rac1 mRNA were detected in all four ovarian tumor cells. There was a strong direct correlation between the levels of Tiam1 and Rac1 mRNA expression and migration potentials of all four ovarian cancer cells in vitro experiments. The increased expressions of Tiam1 mRNA were coincident with those of Rac1 mRNA, with a parallel relationship (P = 0.003, r = 0.874). Levels of Rac1 mRNA expression were significantly correlated with the potentials of tumor cell migration (P = 0.042, r = 0.814). CONCLUSION: Tiam1-Rac1 signaling pathway plays a positive role in assessing tumor cell invasion and metastasis and provides a new target for gene therapy of ovarian cancer.
BACKGROUND & OBJECTIVE: Breast cancer resistance protein (BCRP) was overexpressed in topotecan (TPT)-selected human ovarian cancer cell line A2780/TPT, strongly suggesting BCRP to be responsible for the drug-resistance of ovarian cancer. The current study was designed to investigate the reversal effect of BCRP antisense oligonucleotide (ASODN) on topotecan- resistant A2780/TPT cells. METHODS: The antisense-phosphorothioate oligonucleotide including the translation initiation site of BCRP mRNA was artificially synthesized, and the sense oligonucleotide (SODN) corresponding to the ASODN was also synthesized as control. Lipofect-2000 (LF) was used for the transfer of either ASODN or SODN into A2780/TPT cells. The changes of BCRP mRNA expression, intracellular fluorescence intensity of rhodamine and resistance index to topotecan of in vitro transfected A2780/TPT cells were detected respectively by reverse transcription-polymerase chain reaction (RT-PCR),flow cytometry (FCM),and methyl thiazolyl tetrazolium (MTT) assay. RESULTS: The transfer of ASODN/LF into A2780/TPT cells resulted in:(1)a 59.42% reduction of BCRP mRNA level (P< 0.05); (2)an obviously increased intracellular rhodamine fluorescence intensity from 5.42 to 16.63(P< 0.05); (3)a decreased resistance index to topotecan from 25 to 5 indicating sensitivity to topotecan in A2780/TPT cells recovered, as compared with non-transfected cell. But after transfecting SODN, no significant change could be measured. CONCLUSION: ASODN transfection may partly reverse BCRP-mediated drug- resistance of ovarian cancer cells.