Radiation signature on exposed cells: Relevance in dose estimation

The radiation is considered as a double edged sword, as its beneficial and detrimental effects have been demonstrated. The potential benefits are being exploited to its maximum by adopting safe handling of radionuclide stipulated by the regulatory agencies. While the occupational workers are monitored by personnel monitoring devices, for general publics, it is not a regular practice. However, it can be achieved by using biomarkers with a potential for the radiation triage and medical management. An ideal biomarker to adopt in those situations should be rapid, specific, sensitive, reproducible, and able to categorize the nature of exposure and could provide a reliable dose estimation irrespective of the time of the exposures. Since cytogenetic markers shown to have many advantages relatively than other markers, the origins of various chromosomal abnormalities induced by ionizing radiations along with dose-response curves generated in the laboratory are presented. Current status of the gold standard dicentric chromosome assay, micronucleus assay, translocation measurement by fluorescence in-situ hybridization and an emerging protein marker the γ-H2AX assay are discussed with our laboratory data. With the wide choice of methods, an appropriate assay can be employed based on the net.     

Can sonographers reliably identify anatomic features associated with Down syndrome in fetuses?

To standardize femur measurement for the identification of fetuses at risk for Down syndrome, sonographers of varying professional experience and background measured the femurs of 20 Down syndrome fetuses and 709 normal control fetuses. A regression analysis performed to compare biparietal diameter to femur length on the 709 control fetuses yielded the following formula: expected femur length = -9.3105 + 0.9028.biparietal diameter. A ratio of measured-to-expected femur length of 0.91 or lower indicated Down syndrome with a sensitivity of 40%, a specificity of 95%, and a positive predictive value of 3.1%. Eight of the 20 fetuses with Down syndrome (40%) also had a thickened nuchal fold (6 mm or larger). If the nuchal fold findings had been considered with the femur length findings, two more of the fetuses with Down syndrome would have been identified, yielding a sensitivity of 45% and a positive predictive value of 4.3%. Because these measurements were made by eight sonographers rather than a single experienced sonologist, these results could be achieved in most ultrasound laboratories where measurements are done primarily by sonographers.     

竹叶椒化学成分的研究

自芸香科花椒属植物竹叶椒Zanthoxylum planispinum Sieb. et Zucc根的石油醚提取物中分离得到三种结晶。经物理常数测定,光谱(IR.NMR和MS)及X-射线单晶衍射分析,确定了化合物Ⅲ的绝对构型为(1R,2R,5R,6S)-2-(3′,4′-二甲氧基苯基)-6-(3″,4″-亚甲二氧苯基)双骈四氢呋喃,是一个新化合物,命名为竹叶椒脂素(L-planinin)。化合物Ⅰ为β-香木脂醇(β-amyrin),化合物Ⅱ为L-细辛脂素(L-asarinin),这三种化合物均系首次从本植物中分离得到。     

Hepatitis C infection among drug users attending general practice

Background The prevalence of hepatitis C (HCV) infection among injection drug users is high and addiction-related care is increasingly being provided by GPs in Ireland. Aims To determine the prevalence and associated factors of HCV infection among injecting drug users attending general practice. Methods The records of 571 patients attending 42 general practices in the Eastern Regional Health Authority (ERHA) area for methadone maintenance treatment were reviewed. Results The HCV status was recorded in 380 cases (67%). Of these, 193 had a test performed by their GP, 74 had been tested by another service and 113 had no evidence of being tested, but HCV status was recorded based on information provided by the patient himself. A total of 276 cases were identified as being HCV positive (prevalence 73%), with no difference in prevalence between the three sources of information (p=0.12). A history of injecting drug use was the major determinant of testing for HCV. Conclusions While a large proportion of drug users attending GPs for methadone maintenance treatment are known to be HCV positive, a considerable number have not been tested. Barriers to testing need to be explored to facilitate comprehensive screening.     

一叶萩碱全合成的研究

以1,4-环己二酮为原料经与哌啶缩合、还原、乙酸汞环合、碱催化分子内缩合等11步反应完成了一叶萩碱的全合成。合成品的熔点及光谱数据与天然一叶萩碱的熔点及光谱数据一致。     

蝙蝠葛苏林碱的抗致心律失常性迟后除极

应用标准微电极技术，探讨蝙蝠葛苏林碱(Ds)对豚鼠心室乳头肌迟后除极(DAD)和触发活动(TA)的影响。DS 50 um01.L^-1可消除哇巴因和咖啡因引起的TA，抑制异丙肾上腺素诱发TA。使低K⁺高Ca²⁺、苯肾上腺素诱导TA的发生率分别由 100，75％降低到9.1及22.2％，显著抑制上述因素诱发的DAD。表明Ds对DAD和TA有良好的抑制作用。