What is the origin of ulcerative colitis? Still more questions than answers

Despite more than a century of existence as a clinical entity, the true origin of ulcerative colitis still remains elusive. Several factors probably contribute to the development of this condition. Recently discovered technologies have clarified the role of bacterial species, which may account for intestinal dysbiosis, as a factor triggering ulcerative colitis. Genetic susceptibility together with abnormal innate immunoreactivity probably comprise the essential prerequisites for the initiation and perpetuation of ulcerative colitis. Although the genetic background has been more clearly recognised in patients with Crohn's disease than in those with ulcerative colitis, some candidate loci associated with ulcerative colitis have also been intensively studied. Additionally, environmental factors may interfere with inherent predispositions to ulcerative colitis, and either suppress or reinforce them. Whatever the origin, the search for the aetiology of ulcerative colitis must have the same goal: the improvement of treatment and the quality of life in patients with ulcerative colitis.     

Haemophilus influenzae type b meningitis: how much better is prevention than cure?

Haemophilus influenzae type b (Hib) is a major cause of meningitis and pneumonia in children. In Papua New Guinea (PNG) more than 20% of Hib are now resistant to chloramphenicol, and resistant Hib meningitis treated with chloramphenicol results in certain death or severe brain injury. Third-generation cephalosporins are a therapeutic option but are very expensive, while the Haemophilus influenzae type b conjugate vaccine would provide effective prevention. In a province of 380,000 people, using ceftriaxone as standard treatment for meningitis in all health facilities would only save an estimated 8 more lives per year than using chloramphenicol, and cost US dollars 1514 per additional life saved. Introduction of Hib vaccine would save, each year, 61 more lives than using chloramphenicol and 53 more lives than using ceftriaxone for meningitis treatment. The cost of a vaccination strategy for Hib meningitis would be US dollars 1216 for each of the 61 additional lives saved. Hib vaccine would be by far the most effective intervention to reduce mortality and severe neurological disability from Hib meningitis in PNG. Nationwide introduction of Hib vaccine is urgently needed, as antibiotics are now less effective in this disease than ever before.     

Active learning for clinical text classification: is it better than random sampling?

Objective

This study explores active learning algorithms as a way to reduce the requirements for large training sets in medical text classification tasks.

Design

Three existing active learning algorithms (distance-based (DIST), diversity-based (DIV), and a combination of both (CMB)) were used to classify text from five datasets. The performance of these algorithms was compared to that of passive learning on the five datasets. We then conducted a novel investigation of the interaction between dataset characteristics and the performance results.

Measurements

Classification accuracy and area under receiver operating characteristics (ROC) curves for each algorithm at different sample sizes were generated. The performance of active learning algorithms was compared with that of passive learning using a weighted mean of paired differences. To determine why the performance varies on different datasets, we measured the diversity and uncertainty of each dataset using relative entropy and correlated the results with the performance differences.

Results

The DIST and CMB algorithms performed better than passive learning. With a statistical significance level set at 0.05, DIST outperformed passive learning in all five datasets, while CMB was found to be better than passive learning in four datasets. We found strong correlations between the dataset diversity and the DIV performance, as well as the dataset uncertainty and the performance of the DIST algorithm.

Conclusion

For medical text classification, appropriate active learning algorithms can yield performance comparable to that of passive learning with considerably smaller training sets. In particular, our results suggest that DIV performs better on data with higher diversity and DIST on data with lower uncertainty.     

Reasons Why Laypeople Make Better Administrators

In the 1990s in the United States, physicians took a greater interest in the organization and the management of the health care system. Managed care has taken away the decision making process on many patients and doctors are trying to become administrators to get control back. Many believe this is a positive outcome since they have an understanding of the clinical processes. But if they are to become hospital administrators, they need     

亡羊补牢犹未为晚--从"马加爵案"反思大学生心理教育

从“马加爵案”了解到当今大学生的心理现状及其表现,深入剖析了当今大学生产生心理问题的原因并谈论了从学校、家庭、社会等3方面解决的方法和对策。     

小心无大错？

据本周一篇综述估计，在美国，CT扫描与所有肿瘤的相关危险因子大约为2％。伦敦自由记者Zosia Kmietowicz质疑私人诊所日渐红火的CT筛查是否真正安全可靠     

酶标仪步进进板测定的精密度优于连续进板测定

目的 :比较酶标仪步进进板测定和连续进板测定的精密度。方法 :用两种进板方式分别重复测定不同浓度的重铬酸钾溶液的吸光度值 ,计算标准差 ( s)和变异系数 ( CV)。结果 :步进进板测定的标准差和变异系数都小于连续进板测定 ,变异系数都有随着溶液浓度的增高而减小的趋势 ,标准差逐渐增大。结论 :步进进板测定的精密度明显高于连续进板测定。     

糖尿病眼底病防治指南

糖尿病已成为我国主要的公共卫生问题．1970年我国成年人中糖尿病患病率不足1.0％．二十多年来糖尿病患病率增加了近4倍．目前我国大量无症状的糖尿病病人未被发现．已确诊的患者．估计约有60％血糖控制很差．糖尿病控制越差．视网膜病变的发生率越高．视力丧失的危险性越大。因此．对糖尿病的严重危害性必须有足够的认识．对糖尿病视网膜病变的防治要以预防为主．做到早期发现．早期诊治．早期康复。本篇糖尿病眼底病防治指南正是本着这个精神．简要地．提纲擎领地阐述了糖尿病视网膜病变防治原则．希望对从事糖尿病视网膜病变治疗保健的医务人员．以及对糖尿病或糖尿病视网膜病变的患者能够有所帮助．[编者按]     

涎腺辐射损伤的防治

涎腺辐射损伤是头颈部肿瘤放疗最常见的并发症和后遗症,其发生率高。涎腺辐射损伤导致唾液分泌量锐减,出现口腔干燥症,给患者造成极大痛苦,严重地影响患者的生存质量,是放疗中急待解决的问题。目前尚无完全有效的预防和治疗方法,多采取对症治疗。本文就涎腺辐射损伤的发病机制及防治予以综述。     

心脏性猝死的防治

1　 定义心脏性猝死 (ｓｕｄｄｅｎｃａｒｄｉａｃｄｅａｔｈ ,ＳＣＤ)是指由于心脏原因而引起的突发性自然死亡 ,从先兆症状到出现生物学死亡发生在 1ｈ以内。猝死发生前可以有或没有心脏病表现 ,特征是其发生不可预测、发生的时间和发生的地点不可预知。心脏性猝死定义中最关键的词是“自然性”、“突然性”和“不可预知性”。由于看问题的方法和角度不同 ,临床医生、流行病学家、病理学家们对猝死的定义从来就没有统一过 ,但这并不妨碍我们对疾病认识和进行有效地防治。从临床角度讲 ,心脏性猝死经历 4个阶段 ,即先兆症状、起病、心脏骤…