ABSTRACT
Pelvic radiotherapy is a way for treatment of most pelvic tumors, of which the pelvic insufficiency fracture (PIF) is a long-term complication. In this review, research progress of pelvic insufficiency fracture is summarized and discussed. The pathogenesis of PIF is mainly about inhibition of osteoblasts and the risk factors of PIF include old age, postmenopausal status, absence of hormonal replacement therapy, high number of births, smoking history, low body mass index (BMI), concurrent rheumatoid arthritis, concurrent diabetes mellitus, intracavitary brachytherapy of the high dose rate (HDR-ICBT), high dose of radiotherapy, etc. Effective drugs for prevention or treatment of PIF have not been found yet. Delayed diagnosis and misdiagnosis of PIF can cause serious consequences. As a result, further studies are needed to guide clinical work.
ABSTRACT
Objective To observe the effect of PIF1 knockdown on cell growth and cell cycle arrest induced by ionizing radiation.Methods HeLa cell lines that consistently down-regulated PIF1 were prepared by the lentivirus granules interfering technology and confirmed by real-time PCR and Western blotting.The effect of down-regulation of PIF1 on cell growth and cell cycle arrest induced by ionizing radiation was evaluated by cell counting and flow cytometry.Results HeLa cell lines consistently down-regulating PIF1 were established.The growth of HeLa that down-regulated PIF1 was inhibited greatly after 4 Gy of γ-ray irradiation.There was little cell proliferation until the 5th day post 4 Gy γ-ray.Moreover, the S phase block and G2/M phase block of PIF1 knock-downed cell lines were significantly delayed after 8 Gy γ-ray irradiation.Conclusion Knockdown of PIF1 can significantly enhance the radiation sensitivity and delayes the S phase block and G 2 /M phase block induced by ionizing radiation.
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This study was aimed to confirm animal model and evaluating indicators of the chronic obstructive pulmonary disease combined with pulmonary interstitial fibrosis (PIF-COPD). PIF-COPD rats were induced by intratracheal administration of Bleomycin(BLM, 6 mg·kg-1) and cigarette smoke stimulation for 47 days. After that, the lung function and index were measured. Changes of pathomorphism of lung were observed with hematoxylin-eosin staining. Collagen protein I and III were determined by Sirius red staining. The protein antibody microarray chip was employed for serum cytokine expression pattern measurement. The results showed that in the lung function testing, the central airway resistance, tissue damping, dynamic elasticity of model rats increased significantly and the dynamic compliance reduced significantly. The lung index of model rats increased significantly (compared with the control group, P < 0.01). The pathological tests showed that lung tissues of model rats showed emphysema and fibration with inflammatory infiltration, and content of collagen type I and III increasing significantly. The contents of MMP-8, TIMP-1, IL-10, IL-13, PDGF-AA, Beta-NGF of model rats serum increased obviously compared with the control group and RAGE reduced compared with the normal control. It was concluded that rats which were induced by intratracheal administration of BLM (6 mg·kg-1) and cigarette smoke stimulation for 47 days can be used as animal model establishment of PIF-COPD. The respiratory function and serum levels of MMP-8, TIMP-1, IL-13, PDGF and NGF can be used as evaluating indicators of PIF-COPD model.
ABSTRACT
Baculoviruses produce two viral phenotypes, the budded virus (BV) and the occlusion-derived virus (ODV). ODVs are released from occlusion bodies in the midgut where they initiate a primary infection. Due to the lack of an in vitro system, the molecular mechanism of ODV infection is still unclear. Here we present data demonstrating that Helicoverpa armigera nucleopolyhedrovirus (HearNPV) ODV infected cultured Hz-AM1 cells in a pH dependent manner. The optimal pH for ODV infection was 8.5, which is same to that in the microvilli of midgut epithelial cells, the ODV native infection sites. Antibodies neutralization analysis indicated that four HearNPV oral infection essential genes p74, pif-1, pif-2 and pif-3 are also essential for HearNPV ODV infection in vitro. Thus, HearNPV-HzAM1 system can be used to analyze the mechanism of ODV entry.
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Objective To establish a new method for assessing the effects of environmental factors on human health.Methods Based on the environment part of the frame for comparative risk assessment(CRA) of WHO,the frame and index system for environmental contamination risk assessment which accorded with the situation in China was developed.With the prevalence of different exposure level,RR and the choice of counterfactual scenario,the potential impact fraction(PIF) was estimated.Then an example on the study of liver cancer related with water pollution was used to show the new frame.In this example,the contaminated water was regarded as the environmental factor,incidence of liver cancer was regarded as variable of health,and the analysis was performed with spatial interpolation,counterfactual analysis and CRA theory.Results The quantity of COD of river water in this area was estimated with ordinary Kriging interpolation,and the accumulated exposure of COD was calculated with the trend of annual COD,and the number of population exposed to COD was estimated at same time.In accordance with the different level of pollution and the RR relate to liver cancer,the trend with monotonically increasing showed.At same time,the values of PIF illuminated that 75.72% in male and 66.39% in female would avoid death for liver cancer if the level of contaminated water could be reduced to the level of the control areas.Conclusion The frame includes CRA,spatial analysis and counterfactual analysis is a good approach to assess the health effects of environmental factors.
ABSTRACT
Objective To elucidate physiological functions of human PIF1 helicase at the molecular level,purify N-terminal truncated PIF1 helicase,PIF1△N,and assay its biochemical properties.Methods The N-terminal cDNA sequence of PIF1 helicase was amplified by PCR using the Hela cell cDNA library as template.The cDNA with a histidine tag at the N-terminus was inserted into the pET20b vector to produce recombinant plasmid.The recombinant PIF1△N was successfully expressed by co-transforming a plasmid encoding rare rRNA.At 4 ℃ through a series of affinity column the recombinant PIF1△N protein was purified by fast protein liquid chromatograph.The biochemical activity of PIF1△N was assayed.Results The cDNA fragment of human PIF1 from 540～1 923 was cloned from Hela cDNA library,and the recombinant PIF1△N protein was successfully overexpressed in E.coli.The purification procedure of PIF1△N protein was established and its biochemical activity was identified.Conclusion N-terminal truncated PIF1 helicase,PIF1△N,has ATPase activity,which is DNA and Mg2+ dependent.