Design of clinical trials for chronic diseases: implications for periodontal disease

In order to make effective use of the statistical theory of design of clinical trials for chronic diseases such as periodontal disease, certain issues must be considered. Any clinical trial requires that the disease definition be well-specified; that patient eligibility be explicit; that the observation times be explicit; that the duration and endpoint of therapy be specified; that the duration of subsequent followup observation be specified; and that the unit of observation (e.g., tooth, set of teeth, patient) be defined. In a chronic disease, the potential biases that can readily be introduced by self-selection of patients who enter the trial and/or who return for subsequent observation become more important, because subjects are required to remain on treatment and/or observation for prolonged periods. Further, the cyclical nature of some chronic diseases may require special attention to baseline definitions of active disease and disease outcome. These issues are illustrated with examples from clinical trials of hypertension, breast cancer screening, and Polycythemia Vera. Implications for periodontal disease are discussed.     

改良泪道探通术治疗新生儿泪囊炎

新牛儿泪囊是婴幼儿常见病，作者应用自制的泪道探通冲洗针对28例新生儿泪囊炎进行了泪道探通冲洗治疗观察．疗效满意．报告如下。     

Neonatal necrotizing enterocolitis

PURPOSE: A retrospective, 12-year review of neonatal necrotizing enterocolitis was undertaken at a county hospital, with emphasis on presentation signs and symptoms. METHODS: Eighty-two patients with presence of intramural air were included in the study. The following signs and symptoms were studied: evidence of respiratory distress, use of umbilical catheters, white blood cell count and temperature at presentation, time interval from birth to diagnosis and time interval from diagnosis to operative intervention, presence of intramural air, air in biliary tree or free air, changes in abdominal girth, and presence of occult or gross blood in stools. Comparison was done among infants who had surgical or medical treatment, premature and full-term infants, and infants who had neonatal necrotizing enterocolitis less than or more than 20 days after birth. RESULTS: Eleven patients had a fatal outcome, with an overall survival of 87 percent. Sixty-four patients were treated medically and 18 had operative treatment. Mortality of the surgically treated group was 44 percent. Neonates who had surgical intervention had a left shift of the white blood cell count more commonly present, and all had documented abdominal distention. There were 62 premature and 20 full-term neonates in the group. Full-term neonates developed neonatal necrotizing enterocolitis earlier after birth (5.3 days compared with 15.3 days in the premature neonate group). Full-term neonates had a better prognosis in our series. Presentation of symptoms more than 20 days after birth did not change outcome. CONCLUSION: Our results reflect the experience of a community-based hospital. Clinical acumen remains the cornerstone of diagnosis and management.     

脐带缠绕与新生儿窒息及分娩方式

目的 探讨脐带缠绕与新生儿窒息及分娩方式的关系。方法 回顾性分析2001年5月于2002年4月脐带缠绕246例，与同期分娩的无脐带缠绕者800例进行对照性研究。结果 脐带缠绕组新生儿窒息和剖宫产率高于对照组，差异有显著性（P＜0．05，P＜0．01）；脐带越长，脐带缠绕率越高；脐带长度正常，新生儿窒息率低，脐带过长及过短，新生儿窒息率高；脐带缠绕周数越多，新生儿窒息率越高，差异有显著性（P＜0．01）。结论 脐带缠绕与脐带长度有关，脐带缠绕可导致新生儿窒息，故对脐带缠绕者应加强产前诊断及产时监护。     

A simple method for screening assessment of acute toxicity of chemicals

We proposed a simple method for screening assessment of acute oral and dermal toxicity using only three rats and mice of each sex at each dose level. Animals were first treated with chemicals at a dose of 2000 mg/kg and were carefully observed for compound-related morbidity and mortality. If none of the animals died, the following toxicity tests were suspended. If some of the animals died, toxicity tests at doses of 200 and 20 mg/kg were performed. The approximate LD₅₀ values calculated by this method showed little difference between two separate laboratories and were in good agreement with LD₅₀ values reported in the literature. Our toxicological data also showed that LD₅₀ values were about 2–2.5 times the MNLD (maximum non lethal dose) in acute oral and dermal toxicity. This meant that a chemical could be regarded as having an LD₅₀ of about 4000 mg/kg or higher when there was no mortality at the dose of 2000 mg/kg. A chemical with such low toxicity would not require further testing for lethal effects. Therefore, this simple method combining the fixed-dose procedure with the limit test is suitable for determination of approximate LD₅₀ values of chemicals and for screening for necessity for classical full LD₅₀ test using many animals.This work was supported by a grant from Ministry of Health and Welfare in Japan (No. 467 and 511)     

新生儿呕吐性疾病的消化道造影研究

目的:研究新生儿呕吐性疾病的造影技术,探讨其影像特征。方法:对比剂引入方式采用吸吮法和插胃管抽液后再注入对比剂两种方法;选用对比剂有6 0 %～80 % (W/V)的硫酸钡混悬液30～4 0ml或30 %泛影葡胺30ml;采用不同体位多轴位观察摄片,并对5 4例造影表现进行分析。结果:5 4例新生儿消化道造影均满足诊断要求,其中先天性幽门狭窄11例(19 6 % ) ,胃食管反流34例(6 3 0 % ) ,环形胰腺9例(16 .7% )。经手术治疗2 0例均与术前X线诊断相一致。结论:传统的上消化道造影是诊断新生儿呕吐病因的有效方法,熟练掌握造影技术和特有的造影征像能够及时地明确诊断。     

新生儿窒息124例临床分析

目的探讨预防新生儿窒息的措施，以降低新生儿窒息的发生率。方法收集我院124例新生儿窒息的临床资料，分析发病的相关高危因素。结果窒息的相关因素依次为：早产因素34例居首位，占27．4％；羊水过少占14．5％；胎位异常占10．5％；产程异常占9．7％；脐带因素（缠绕、脱垂及过短）占8．9％；巨大儿占8．9％；胎盘早剥及前置胎盘占6．5％；妊娠高血压综合征占5．6％；宫内生长迟缓（IUGR）占3．2％。结论加大孕产妇分级管理的力度，加强孕期保健和产前检查，适时纠正臀位，尽量减少早产，及早发现和正确处理胎儿宫内窘迫，是降低新生儿重度窒息的有效措施。