Cross-talk elimination in determination of gross α and gross β activities using a low-background α/β gas-flow proportional counter / 中国辐射卫生

Objective To explore cross-talk elimination method in the determination of gross α and gross β activities using a low-background α/β gas-flow proportional counter. Methods A CLB-104 low-background α/β gas-flow proportional counter was used in this study. First, the α threshold was increased to eliminate the cross-talk counting caused by β particles in the α channel. Then, the α-β anticoincidence threshold was reduced to eliminate the cross-talk counting induced by low-energy α particles in the β channel, and β counts were corrected to eliminate the counts induced by internal convention electrons in the β channel. Finally, gross α and gross β activities of non-saline water samples with different activity levels were determined and compared with gross α and gross β activities of the same samples determined on a BH1227 low-background α/β solid scintillation counter, in order to verify effectiveness of the cross-talk elimination method. Results By eliminating the cross-talk counts of β particles in the α channel and the cross-talk counts of α particles in the β channel, and deducting the counts of internal convention electrons in the β channel, the gross α and gross β activities of the same samples determined by CLB-104 were consistent with the values determined by BH1227. Conclusion Cross-talk counts induced by low-energy α particles or β particles can be eliminated by threshold adjustment, and the counts caused by internal convention electrons in the β channel can be eliminated by correction.

Prevalence and Molecular Characterization of Echinococcus granulosus Sensu Stricto in Northern Xinjiang, China

Echinococcus granulosus is an important zoonotic parasite globally causing cystic echinococcosis (CE) in humans and animals. In this study, prevalence of CE and variation of cox1 gene sequence were analyzed with isolates E. granulosus collected from different areas in northern Xinjiang, China. The survey showed that 3.5% of sheep and 4.1% of cattle were infected with CE. Fragment of cox1 was amplified from all the positive sheep and cattle samples by PCR. In addition, 26 positive samples across the 4 areas were included. The isolates were all E. granulosus sensu stricto (s.s.) containing 15 haplotypes (Hap1-15), and clustered into 2 genotypes, G1 (90.1%, 91/101) and G3 (9.9%, 10/101). Hap1 was the most common haplotype (48.5%, 49/101). Hap9 were found in humans samples, indicating that sheep and cattle reservoir human CE. It is indicate that E. granulosus may impact on control of CE in livestock and humans in the region.

Evaluation of COBIO XS automated urine sediment analyzer in screening urinary tract infection / 国际检验医学杂志

Objective To evaluate the clinical application of COBIO XS automated urine sediment analyzer for screening urinary tract infection(UTI) .Methods Midstream urine samples were collected from 182 patients with suspected UTI .White blood cell counts(WBC) and bacteria counts(BACT) were determined by COBIO XS automated urine sediment analyzer .By comparing with quantitative urine culture as the golden standard of UTI .The area under the ROC curve(AUC) was constructed to evaluate the dis‐criminative power of variables to predict UTI .Results The positive rate of urine culture was 30 .8% .The isolated rate of Esche‐richia coli ,Enterococcus species and proteus species were 53 .6% ,16 .1% ,10 .7% ,respectively .ROC curve analysis showed that AUC was 0 .808(95% CI 0 .710-0 .867) for WBC and 0 .899(95% CI 0 .797 -0 .923) for BACT .The best cutoff value for WBC was 50/μL ,sensitivity was 89 .0% ,specificity was 83 .8% ,positive predictive value was 86 .3% and negative predictive value was 93 .7% .The best cutoff value for BACT was 110/μL ,sensitivity was 82 .5% ,specificity was 85 .6% ,positive predictive value was 78 .5% and negative predictive value was 88 .0% .Conclusion COBIO XS analyzer is adopted to conduct rapid and reliable a screen‐ing tool for UTI .

Molecular mechanism of metastasis in breast adenocarcinoma regulated by xCT / 军事医学

Objective To investigate the mechanism of xCT on tumor metastasis in breast cancer cell MDA-MB-231. Methods Wound scratch assay and Transwell assay were performed to evaluate the effect of disruption and knockdown of xCT on cell migration and cell invasion in breast cancer cell MDA-MB-231 .Western Blot and RT-PCR were used to detect the expression levels of autophagy and EMT related markers in breast cancer cell MDA-MB-231 after treatment with sulfasalazine (SASP), an inhibitor of xCT activity and SLC7A11-RNAi.Results Both the scratch assay and the transwell migration assay showed that inhibition of xCT reduced the motility of MDA-MB-231 .The expression level of autophagy related protein LC3-Ⅱ/LC3-Ⅰwas elevated, the protein level of transcription factor Snail was down-regulated, while the mRNA level of Snail did not change in xCT inhibited MDA-MB-231 cells compared with MDA-MB-231 cells.Epithelial marker E-cadherin was up-regulated but mesenchymal marker Vimentin was down-regulated when xCT was deficient.Con-clusion Our current studies show that xCT is an endogenous regulator of tumor growth and metastasis in MDA -MB-231 and the expression level of xCT determines the phenotypes of MDA-MB-231 cells in invasion and migration in vitro.Inhibition of xCT can activate autophagy , induce the degradation of Snail ,and attenuate the EMT process in highly metastatic MDA-MB-231 cells.