Hypofractionnement en radiothérapie : l’éternel retour

Hypofractionation is not a new idea in radiotherapy. The use of a few high-dose fractions has been proposed by some pioneers of our specialty in the early years of the 20th century. Hypofractionation then reappeared several times in the next decades, based on successive radiobiological concepts, a number of them having been shown to be wrong. The nominal single dose (NSD), for example, so fashionable in the 1970's, dramatically underestimated the late toxicity of the high-dose fractions. Consequently, the NSD was directly responsible for a significant increase of the incidence and of the severity of late complications in large cohorts of patients. The linear-quadratic model (LQ) unequivocally improved our understanding of fractionation sensitivity, but one has to keep in mind its limitations, both in the areas of low and high doses per fraction. For more than a decade, prostate cancer has been the subject of fierce discussions about its sensitivity to fractionation. A number of studies have suggested an unusually low (for a malignant tumor) alpha/beta ratio. However, the available data do not allow a precise evaluation of this ratio; “very low” (1.5 Gy), with an advantage of hypofractionation in terms of local control? Or simply “low” (3–4 Gy), only allowing a reduction of the total number of fractions (with a dose adequately reduced)? While waiting for complementary data, it is advised to remain very careful when modifying the classical schemes towards hypofractionation.     

Evaluation of extraction parameters for total oxalate determination in spinach using Design of Experiment analysis

The interaction of pH, temperature and time on the acid extraction of total oxalates from homogenised fresh stems and leaves of spinach (Spinacia oleracea L.) were investigated. The extractions were carried out using HCl solutions between pH 0.93 and 5.81 and temperatures ranging from 25 to 95 °C. The extraction times ranged from 15 to 120 min. The released oxalate was measured using a standard HPLC method. A Design of Experiments (DOE) method using Design Expert DX9 was used to determine the optimum extraction parameters. Increasing the extraction time from 15 to 120 min had no significant effect while increasing the extraction temperature from 25 to 95 °C significantly (P < 0.01) increased the recovery of total oxalates. Reducing the pH of the extraction solutions from 5.81 to 0.93 significantly (P < 0.001) increased the total amount of oxalate extracted. There was no significant correlation between the pH of the extraction solutions and the extraction temperatures. The highest amount of extracted oxalate content in this experiment (856.57 mg/100 g FW) was obtained using an HCl solution of pH 0.93 (0.1 M HCl) at 95 °C.     

厦门市手足口病流行特征分析及发病趋势预测方法研究

目的研究厦门市手足口病的流行特征并探讨季节性时间序列(seasonal autoregressive integrated moving average,SARIMA)模型拟合厦门市手足口病发病趋势预测的可行性。方法选取2011—2013年6家医院报告的手足口病10 540例,利用SPSS19.0对厦门市手足口病的发病情况进行流行病学分析,通过取自然对数、差分等方法对手足口病月发病数序列进行平稳化,然后进行模型参数的估计、检验,最优模型的筛选,最后进行预测分析。计量资料采用χ2检验,P0.05为差异有统计学意义。结果 2011—2013年厦门市手足口病的年平均发病率为97.37/10万,4—7月和9月有两个发病高峰,病例主要分布于5岁以下儿童,占所有病例数的93.85%;病原构成以其他肠道病毒为主,占42.9%,其次为肠道病毒71型(enteriovirus 71,EV71)占39.7%,柯萨奇病毒A6(coxsackie virus A6,Cox A6)仅占17.3%;SARIMA(0,1,0)(1,1,0)12较好地拟合了厦门市手足口病的月发病数据,预测效果良好。结论厦门市手足口病的发病率较高,可以用SARIMA模型进行短期预测,进而指导各项防控措施。     

纤支镜灌洗用于重症肺部感染治疗疗效分析

目的：分析在对重症肺部感染患者实施治疗的过程中纤支镜灌洗的临床治疗疗效。方法选择2013年6月～2015年6月收治的接受重症肺部感染治疗的患者98例为实验研究的对象，按照随机单双法将患者分为观察组（n＝49）和对照组（n＝49），观察组患者运用纤支镜灌洗进行治疗，对照组患者运用常规的治疗方法实施治疗，对比分析两组患者的临床治疗效果。结果观察组患者治疗有效率和致病菌株清除率分别为95．9％、89．5％；对照组患者治疗有效率和致病菌株清除率分别为87．8％、41．4％，观察组患者治疗有效率、致病菌株清除率以及平均住院时间和平均退热时间等均明显优于对照组，差异具有统计学意义（ P＜0．05）。结论在常规治疗的基础上运用纤支镜灌洗对重症肺部感染患者实施治疗可以提高临床治疗的效果和致病菌株的清除率，缩短了患者的平均住院时间和平均退热时间，改善了患者各项临床症状和体征，是一种效果理想且显著的治疗方法，值得临床推广。     

Glutathione S-transferase A1 (GSTA1) release,an early indicator of acute hepatic injury in mice

Three acute hepatic injury models (a CCl₄-induced model, APAP-induced model and ethanol-induced model) in mice were used to study the importance of GSTA1 in acute hepatic injury by comparison with a standard enzyme marker, alanine aminotransferase (ALT). GSTA1 release was demonstrated to be an earlier and more sensitive indicator of hepatotoxicity than was ALT. Significant increases in GSTA1 were detected at 2 h after CCl₄ exposure, while ALT was undetected at this time. GSTA1 was also a more sensitive indicator of hepatotoxicity than ALT after 6 h. In the APAP and ethanol models, GSTA1 was markedly increased earlier than ALT, at 2 h post exposure. The release of GSTA1 was significantly increased at a dose of 12.5 mg/kg (CCl₄ model), 100 mg/kg (APAP model) and 10 ml/kg (ethanol model), the lowest exposure concentration for each model. In contrast, AST release was not statistically significant. These results suggest that GSTA1 can be detected at low concentrations during the early stages of acute hepatic injury and that GSTA1 is a more sensitive and more accurate indicator than ALT.     

How Individuals Feel About the Past,Present, and Future Bears Little Relation to Alcohol-Related Problems,Anxiety, and Depression: A Person-Centered Analysis in a University Sample

Previous studies using bivariate or correlational analyses have established a relationship between alcohol use, symptoms of anxiety and depression, and scores on a range of temporal psychology measures. Temporal psychology measures variously assess the cognitive or affective (or in some cases, both) engagement with the past, present, and future. Although developed and validated in adolescents, recent research has suggested that the Time Attitudes Scale is internally consistent and reliable in adults also. The present study is the first to apply a person-centered approach to assessing the relationship between scores on the Time Attitudes Scale and symptoms of anxiety, depression, and alcohol-related problems in adults. Participants were recruited from a University in England. Results support the validity and internal consistency of the Time Attitudes Scale. Meaningful time attitudes profiles emerged, however, taking the sample size into account, the only substantive finding showed that those with a negative time attitudes profile scored higher on depressive symptomatology than those with a positive profile. While elsewhere, Zimbardo Time Perspective Inventory scores have been shown to be meaningfully related to anxiety, depression and alcohol use, the present study questions the degree to which the affective dimension of temporal psychology is driving that relationship.