Recommendations for the Conduct of Acute Inhalation Limit Tests

This paper reviews the scientific issues related to exposureconcentrations and particle sizes used in acute inhalation limittests. The current United States Environmental Protection Agency(USEPA) recommended exposure concentration for such tests is5 mg/liter, while this level is very high, it is often achievable.On the other hand, its toxicological relevance is questionable.The USEPA recommendation that 25% of the particle distributionbe less than 1 µm is a more difficult issue to address.Physical laws for aerosol particle generation and behavior limitthe minimum size of particles in an exposure atmosphere at aconcentration of 5 mg/liter. Particle size also influences depositionsite in the respiratory tract. Since damage to any region ofthe respiratory tract can produce lethality, and it is not possibleto predict, a priori, the most responsive region of the tractor the most harmful particle size of an untested agent, acutelimit testing should employ particles in a size range that depositsthroughout the entire rodent respiratory tract. Particles between1 and 4 µm mass median aerodynamic diameter (MMAD) arewell suited for such studies. It is, therefore, recommendedthat the limit test concentration should be the highest concentration(up to 5 mg/liter) that can be achieved while still maintaininga particle size distribution having an MMAD between 1 and 4µm.     

胃癌中P16与MDM2的免疫组化研究

目的 :检测胃肿瘤及正常胃组织中P16与MDM2的表达 ,探讨其在肿瘤凋亡中的相互关系。方法 :采用免疫组织化学方法 (SABC法 )。结果 :胃癌中P16阳性率为 69% ,MDM2阳性率为 75 % ,它们与正常胃组织及良性胃肿瘤相比差异均有显著性 (P <0 .0 5 )。结论 :在胃癌的细胞凋亡中 ,P16与MDM2均发挥了其各自对细胞凋亡的作用 ,为临床胃癌的组织学检测提供了理论依据 ,同时也支持胃癌的发生是多基因协同作用的过程     

光动力诱导前部缺血性视神经病变的血浆内皮素-1浓度变化的实验研究

目的观察通过光动力方法诱导鼠前部缺血性视神经病变模型(rAION)与正常鼠的血浆内皮素-1(ET-1)的浓度变化,探讨不同时间段血浆ET-1水平及与rAION水肿的关系,观察血浆ET-1的浓度变化与临床表现是否有同一性。方法依据光动力方法诱导rAION模型,应用SD雄性大鼠40只,随机分为2组:正常对照组20只和模型组20只,模型组再按照不同时间段分组各4只,造模后大鼠自由进食饮水,按第1天、第3天、第5天、第7天、第14天等时间段处死大鼠,心脏采血,离心后分离血浆,通过放射免疫法(RIA)测定血浆ET-1的浓度变化。结果对照组与模型组之间血浆ET-1值有统计学意义(P<0.05);模型组第1天、第3天、第5天、第7天、第14天时间段血浆ET-1值不同时间组之间差别有统计学意义(P<0.05)。结论 SD大鼠造模后血浆ET-l水平短期升高,第7天达到高峰,随后有所下降,但持续在一个高水平。血浆ET-1早期高表达可能是导致缺血性视神经病变视盘水肿增加的一个原因。血浆ET-1的浓度变化与临床表现具有同一性。     

Role of endoscopy in the bariatric surgery of patients

Obesity is an increasingly serious health problem in nearly all Western countries.It represents an important risk factor for several gastrointestinal diseases,such as gastroesophageal reflux disease,erosive esophagitis,hiatal hernia,Barrett’s esophagus,esophageal adenocarcinoma,Helicobacter pylori infection,colorectal polyps and cancer,non-alcoholic fatty liver disease,cirrhosis,and hepatocellular carcinoma.Surgery is the most effective treatment to date,resulting in sustainable and significant weight loss,along with the resolution of metabolic comorbidities in up to 80%of cases.Many of these conditions can be clinically relevant and have a significant impact on patients undergoing bariatric surgery.There is evidence that the chosen procedure might be changed if specific pathological upper gastrointestinal findings,such as large hiatal hernia or Barrett’s esophagus,are detected preoperatively.The value of a routine endoscopy before bariatric surgery in asymptomatic patients(screening esophagogastroduodenoscopy)remains controversial.The common indications for endoscopy in the postoperative bariatric patient include the evaluation of symptoms,the management of complications,and the evaluation of weight loss failure.It is of critical importance for the endoscopist to be familiar with the postoperative anatomy and to work in close collaboration with bariatric surgery colleagues in order to maximize the outcome and safety of endoscopy in this setting.The purpose of this article is to review the role of the endoscopist in a multidisciplinary obesity center as it pertains to the preoperative and postoperative management of bariatric surgery patients.