Role of endonucleases XPF and XPG in nucleotide excision repair of platinated DNA and cisplatin/oxaliplatin cytotoxicity

Resistance of tumor cells to platinum anticancer agents poses a major problem in cancer chemotherapy. One of the mechanisms associated with platinum-based drug resistance is the enhanced capacity of the cell to carry out nucleotide excision repair (NER) on platinum-damaged DNA. Endonucleases XPF and XPG are critical components of NER, responsible for excising the damaged DNA strand to remove the DNA lesion. Here, we investigated possible consequences of down-regulation of XPF and XPG gene expression in osteosarcoma cancer cells (U2OS) and the impact on cellular transcription and DNA repair. We further evaluated the sensitivity of such cells toward the platinum anticancer drugs cisplatin and oxaliplatin.National Cancer Institute (U.S.) (Grant Number CA034992.)National University of Singapore.German Academic Exchange Service (DAAD

Duration of light and the wings op the aphid macrosiphum solanifolii

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47501/1/427_2005_Article_BF02251943.pd

Pyrethrins Protect Pyrethrum Leaves Against Attack by Western Flower Thrips, Frankliniella occidentalis

Pyrethrins are active ingredients extracted from pyrethrum flowers (Tanacetum cinerariifolium), and are the most widely used botanical insecticide. However, several thrips species are commonly found on pyrethrum flowers in the field, and are the dominant insects found inside the flowers. Up to 80 % of western flower thrips (WFT, Frankliniella occidentalis) adults died within 3 days of initiating feeding on leaves of pyrethrum, leading us to evaluate the role of pyrethrins in the defense of pyrethrum leaves against WFT. The effects of pyrethrins on WFT survival, feeding behavior, and reproduction were measured both in vitro and in planta (infiltrated leaves). The lethal concentration value (LC50) for pyrethrins against WFT adults was 12.9 mg/ml, and pyrethrins at 0.1 % (w/v) and 1 % (w/v) had significantly negative effects on feeding, embryo development, and oviposition. About 20-70 % of WFT were killed within 2 days when they were fed chrysanthemum leaves containing 0.01-1 % pyrethrins. Chrysanthemum leaves containing 0.1 % or 1 % pyrethrins were significantly deterrent to WFT. In a no-choice assay, the reproduction of WFT was reduced significantly when the insects were fed leaves containing 0.1 % pyrethrins, and no eggs were found in leaves containing 1 % pyrethrins. Our results suggest that the natural concentrations of pyrethrins in the leaves may be responsible for the observed high mortality of WFT on pyrethrum

The value of endocervical curettage after conization for cervical intraepithelial neoplasia

The objective of this study is to assess the value of postcone endocervical curettage, after conization of cervical intraepithelial neoplasia or carcinoma as a predictive tool for residual lesions. This is a retrospective observational study. All data were obtained by the University Hospital of Zurich, Department of Gynaecology. One hundred fifty patients underwent hysterectomy within 12 months after conization and endocervical curettage from 1993 to 2006. To analyze the sensitivity, specificity, and the positive predictive value (PPV) and negative predictive value (NPV) of the endocervical curettage after conization, we used the Fisher exact test and χ(2) test. The main outcome measures are the sensitivity and specificity as well as the PPV and NPV of the postconization endocervical curettage. The endocervical curettage exhibited a sensitivity of 0.38, a specificity of 0.85, a PPV of 0.56, and an NPV of 0.73. Comparing patients younger than 50 years to women 50 years or older, endocervical curettage had a sensitivity of 0.35 and 0.44, a specificity of 0.83 and 0.94, a PPV of 0.46 and 0.88, and an NPV of 0.76 and 0.63, respectively. The endocervical curettage after conization of cervical intraepithelial neoplasia does not generally improve the prediction of residual lesions. However, in women 50 years or older, a higher specificity and PPV, 0.94 and 0.88, respectively, was observed. Therefore, this subgroup of patients may benefit from an endocervical curettage