Biomedical subjects

Qian Xu

Publications and source records attributed to Qian Xu.

40 records · Page 3Linked to original sources

PubMed2003

[The expression of cytochrome P450 1A1 of endothelial cells induced by benzo(a)pyrene].

OBJECTIVE: To explore the effect of benzo(a)pyrene (BaP) on the expression and the activities of cytochrome P450 1A1 (CYP1A1) of porcine aortic endothelial cells. METHODS: Porcine aortic endothelial cells were cultured in vitro, and treated with different concentrations of BaP (0, 0.5, 1.0, 5.0, 10.0 micro mol/L) for 24 hours, CYP1A1 expression was determined by Western blot and immunohistochemistry. At the same time, the ethoxyresorufin-o-deethylase (EROD) activities were measured by spectrofluorometer. RESULTS: By Western blot, the expression of CYP1A1 of control cells was not found, but the expression of CYP1A1 of cells treated with BaP was found; By immunohistochemistry, only part of endothelial cells treated with BaP had positive expression of CYP1A1. The peak activities of EROD induced by BaP was at the concentration of 0.5 - 1.0 micro mol/L. CONCLUSION: BaP could induce part of endothelial cells to synthesize CYP1A1. BaP of 0.5 - 1.0 micro mol/L could induce peak activities of EROD.

Animals↗

PubMed2002

[Difference in lymphocyte heat shock protein 71 (HSP71) expression in soldiers of armed police forces from different climatic zones].

OBJECTIVE: To analyze the difference between basal and heat-inducible levels of lymphocyte heat shock protein 71 (HSP71) expression in soldiers from Beijing, Zhengzhou and Guangzhou. METHODS: Flow cytometry and Comet assay were used to detect the level of HSP71 and DNA damage respectively. RESULTS: Comet assay showed that there was no significant DNA damage before and after heat stress at 41 degrees C for 1 h, and also no difference found among the 3 climatic zones(P > 0.05). HSP71 of all soldiers in the 3 zones elevated after stress (P < 0.05). The basal and heat-inducible levels of HSP71 in Beijing soldiers(845.87 +/- 135.60 and 1254. 47 +/- 239.05 mean fluorescence intensity respectively) were higher than those in Guangzhou soldiers(702.73 +/- 184.70 and 861.72 +/- 225.12 mean fluorescence intensity respectively) (P < 0.05). CONCLUSION: The differences of lymphocyte HSP71 expression before and after heat stress among the soldiers from Beijing, Zhengzhou and Guangzhou suggest that basal and heat-inducible levels of lymphocyte HSP71 expression may be considered as a valuable index to evaluate heat tolerance of soldiers in different climatic zones.

Climate↗

PubMedDate not supplied

Quantitative assessment of the infection rate of the entomophthoraceous fungus, Zoophthora anhuiensis against the green peach aphid Myzus persicae.

A two-step method was developed to quantitatively assess the infection rate of the entomophthoraceous fungus, Zoophthora anhuiensis (Li) Humber, on the green peach aphid, Myzus persicae (Sulzer). Firstly, a standard time-dose-mortality relationship, established by modeling data from bioassay 1 at varying conidial dosages (0.4 - 10.4 conidia/mm2) of Z. anhuiensis F97028, was used to yield an estimate of expected mortality probability at a given dosage. Secondly, bioassay 2 was conducted by simultaneously exposing six < or = 4-day-old nymphal colonies to a shower of Z. anhuiensis conidia at each of four dosages (resulting from exposures of 0.3 - 8.0 min). Subsequently, the colonies were separately immersed in a 0.1% chlorothalonil solution for 0.5 min to disinfect all surviving conidia on the host integument from 1 - 12 h after exposure under temperature treatments of 15 and 20 degrees C, respectively. The infection rate during a specific period from the end of the exposure to the immersion was then estimated as the ratio of the observed mortality over the expected mortality probability at a particular dosage. The results showed that the infection of M. persicae from Z. anhuiensis was highly rapid with little difference between aphid colonies maintained at 15 and 20 degrees C before being immersed in the fungicidal solution after exposure. The first 6-hour period after exposure was most crucial to successful infection of the fungus with the infection rate greatly depending on conidial dosages. It took < or = 1 h to infect > 50% of the aphids at a dosage of > 1.5 conida/mm2 and > 90% at > 50 conidia/mm2.

Animals↗

PubMedDate not supplied

[Beneficial effect of maternity leave on delivery].

OBJECTIVE: To identify the contribution of the duration of the prenatal maternity leave on term delivery. METHOD: Characteristics of the prenatal maternity leave and delivery among 363 working women who had delivered a full-term infant at 1 of 4 hospitals in Montreal during 1996 were studied. RESULTS: The presence of an intervention or complication during delivery was observed in 68.9% of the participants. The average duration of the prenatal maternity leave was about 8 weeks (SD = 7). The adjusted risk of a difficult delivery decreased significantly with the duration of the prenatal maternity leave (OR = 0.96; 95% CI: 0.93-0.99). CONCLUSION: The duration of the maternity leave before delivery is associated with an easier term delivery for working women.

Adolescent↗