Animal Models of Barrett's Esophagus and Esophageal Adenocarcinoma–Past,Present, and Future

Esophageal adenocarcinoma is the fastest rising cancer in the United States. It develops from long‐standing gastroesophageal reflux disease which affects >20% of the general population. It carries a very poor prognosis with 5‐year survival <20%. The disease is known to sequentially progress from reflux esophagitis to a metaplastic precursor, Barrett''s esophagus and then onto dysplasia and esophageal adenocarcinoma. However, only few patients with reflux develop Barrett''s esophagus and only a minority of these turn malignant. The reason for this heterogeneity in clinical progression is unknown. To improve patient management, molecular changes which facilitate disease progression must be identified. Animal models can provide a comprehensive functional and anatomic platform for such a study. Rats and mice have been the most widely studied but disease homology with humans has been questioned. No animal model naturally simulates the inflammation to adenocarcinoma progression as in humans, with all models requiring surgical bypass or destruction of existing antireflux mechanisms. Valuable properties of individual models could be utilized to holistically evaluate disease progression. In this review paper, we critically examined the current animal models of Barrett''s esophagus, their differences and homologies with human disease and how they have shaped our current understanding of Barrett''s carcinogenesis.     

Barrett食管及相关并发症的X线探讨

目的:通过16例经内窥镜及病理证实为Barrett食管的钡餐检查表现,初步探讨Barrett食管及其并发症放射学检查的意义。方法:回顾性分析16例Barrett食管的内窥镜和气钡检查的记录及表现,着重探讨气钡检查的X线表现。结果:食管内窥镜和组织学检查全部病例均有炎症改变,其他可见胃食管反流、食管溃疡和食管腺癌。放射学钡餐检查结果:Barrett食管炎4例,Barrett食管溃疡7例,Barrett食管癌5例。结论:Barrett食管及其并发症至今无明确放射学征象,改进对“Z”线的检查技术和方法,有可能提高其发现率。钡餐发现胃食管反流、食管裂孔疝同时并发食管炎、食管溃疡及食管癌者均应考虑到本症的可能。     

MEBO治疗口腔、咽、食管烧伤临床观察

目的:探讨口腔、咽、食管烧伤的治疗方法。方法:对2000年3月-2005年12月,采取口服湿润烧伤膏(MEBO)治疗的25例患者进行回顾性资料总结。结果:25例病人均治愈,无创面感染、食管狭窄、腹泻等并发症。结论:MEBO对口腔、咽、食管等上消化道部位黏膜烧伤疗效确切,方法简单易行。     

人食管不典型增生上皮与原位癌的计算机纹理分析研究

采用计算机图象纹理分析和相关点阵检测技术,对人食管正常粘膜、不典型增生上皮及原位癌的不同纹理特征进行了观察。观察样品为常规病理切片,用计算机图象分析系统检测了组织的纹理特征。对受检图象建立了三种灰色分层关系矩阵,同时计算了8种纹理测度。结果显示,在重度不典型增生上皮和原位癌之间,其纹理测度和相关点阵检测数据均有显著性差异(P<0.05)。全部测量数据经计算机多元逐步判别分析,其正判率达90%以上。本研究结果表明,计算机纹理分析方法可正确地判别食管癌前病变和原位癌的组织结构异型性。提示本技术在食管癌的早期诊断方面具有肯定的实用性价值。     

食管高密度异物(鱼刺)的CT诊断

目的探讨CT在食管异物诊断中的应用价值方法食管异物10例(均为鱼刺),均行常规CT平扫,必要时加CT薄层扫描,再将CT征象与手术及内镜结果比较结果10例食管异物(鱼刺)均为CT所显示,呈大小、形态不一的稍高或高密度影,其中合并食管出血2例,黏膜下血肿1例,脓肿3例及脓胸1例结论常规CT扫描及薄层扫描在食管异物检查中具有重要意义     

Infusion manometry and detection of sphincteric function of crural diaphragm

The principles of infusion manometry in the measurement of lower esophageal sphincter (LES) pressure were laid down in the mid-1960s by L.D. Harris and his coworkers. Dodds and his colleagues were largely responsible for the improvements and advent of the low-compliance manometry. Using side-hole manometry, it is possible to detect accurate LES pressure that correlates with the strength of the antireflux barrier. The LES pressure as measured by the side-hole manometry, shows respiration-induced pressure oscillations. These pressure oscillations were initially thought to be due to the influence of abdominal and thoracic pressures on the LES. However, it was later pointed out that these pressure oscillations were due to the relative motion of the point pressure sensor (side hole of the manometric catheter) and the LES during respiration. Recent studies suggest that active contraction of the crural diaphragm during inspiration is responsible for the pressure oscillations observed in the cat LES pressure tracings. The use of the sleeve device in the measurement of LES pressure during contraction of the diaphragm has been described recently. Using the principles of manometry and sleeve device, it is now possible to identify two lower esophageal sphincters: the smooth muscle LES, traditionally known as the LES, and crural diaphragm, which we have referred to as the external lower esophageal sphincter. The purpose of the following paper is to summarize the general principles of the infusion manometry in the measurement of intraluminal pressure, specifically the LES pressure. The recently developed technique of detection of the sphincteric function of the crural diaphragm by the sleeve device will be discussed. In the last paragraph the limitations of manometry in detection of the muscular contractile activity are described.     

食管内支架置入术并发症分析及防治

目的：分析食管内钛镍记忆合金支架置入术并发症的可能原因及防治方法。方法：共52例病人，食管癌、贲门癌29例，食管胃吻合口狭窄21例，自发性食管破裂2例，共置入各种钛镍记忆合金支架54枚。随访观察3～36个月。结果：内支架置入全部成功，术后患吞咽困难症状均改善。术后出现的并发症包括支架移位3例，支架堵塞9例。吸入性肺炎3例，呕血7例，残余漏2例，疼痛和异物感24例，严重返流症状5例。经过相应的治疗，除2例大呕血患外，其余并发症均得到纠正。结论：虽然食管内钛镍记忆合金支架置入术后有不可忽视的并发症，但经过相应治疗，一般均可纠正，它是治疗食管恶性狭窄和自发性食管破裂有效的方法。     

Cancer risk due to occupational exposure to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) demonstrate carcinogenic activity in animal models. Although some epidemiologic studies have implicated PAHs as risk factors for human cancer, the evidence reported to date has not been consistent. The purpose of this report is to describe the associations between occupational exposure to PAHs in the workplace and each of 14 types of cancer. A population-based, case-control study was carried out in Montreal to investigate associations between a large variety of environmental and occupational exposures on the one hand, and several types of cancer on the other. A detailed job history was obtained from each subject along with information on a number of potential confounders. Each job history was reviewed by a team of experts, who used this information to construct a corresponding history of occupational exposures. Among the PAH exposures considered were benzo(a)pyrene (B(a)P) and five categories of PAHs defined on the basis of the source material, namely, wood, petroleum, coal, other sources, and any source. Altogether, 3,730 cancer patients and 533 population controls were interviewed and their job exposure histories coded. For each of 14 types of cancer analyzed, three control groups were available: other cancer patients, population controls, and the pooled set of cancer and population controls. The associations between 14 cancer types and 6 PAH exposures were analyzed using logistic regression methods. For most types of cancer evaluated, there was no evidence of excess risk due to PAHs at the levels encountered in the occupations in which PAH exposure has been prevalent in the Montreal area. For a few cancer sites–the esophagus, the pancreas, and the prostate gland–there were suggestions of excess risk; these observations are noteworthy hypotheses for further investigation. For lung cancer, there appeared to be an increased risk due to PAHs among nonsmokers and light smokers, but not among heavy smokers.     

Influence of acetylcholine on neuronal activity of monkey amygdala during bar press feeding behavior

Single neuron activity in the monkey amygdala was investigated during cue signalled conditioned bar press feeding behavior and the effects of electrophoretically applied acetylcholine (ACh) and atropine were analyzed. ACh increased the firing rate of one third of the neurons tested; these excitatory responses were inhibited by the muscarinic receptor antagonist atropine. No characteristic location of ACh-sensitive neurons was found, cells were diffusely distributed throughout the amygdala. Activity of ACh-sensitive neurons did not correlate with any particular event during the bar press feeding task. However, continuous application of ACh at low current intensity during the task significantly enhanced the task-related excitatory firing patterns, or markedly attenuated the inhibitory responses. Continuous application of atropine elicited or enhanced inhibitory response patterns. These results suggest that the cholinergic system of the monkey amygdala facilitates neuronal excitation but attenuates inhibition related to various phases of feeding behavior, such as to cue recognition, food aquisition and rewarding process.     

Response of lower esophageal contractility to changing concentrations of halothane or isoflurane: A multicenter study

A multiple-center study was performed to determine the relationship between lower esophageal contractility, clinical signs, and anesthetic concentration as expressed by minimum alveolar concentration (MAC). One hundred four American Society of Anesthesiologists Class I through III patients were exposed to isoflurane (with and without nitrous oxide) or halothane in concentrations of 0.5, 1.0, and 1.5 MAC. Heart rate and systolic blood pressure were continuously monitored. Both the amplitude and frequency of spontaneous and provoked lower esophageal contractions were measured in situ by using a 24-F probe equipped with provoking and measuring balloons. Combined results demonstrated statistically significant correlations (P<0.001) between lower esophageal contractility and MAC. Spontaneous lower esophageal contractions decreased from 1.10±0.12 (SEM) contractions per minute (0.5 MAC) to 0.42±0.05 (1 MAC) to 0.18±0.05 (1.5 MAC). Provoked lower esophageal contractility values decreased from 45±4 mm Hg (0.5 MAC) to 29±3 (1 MAC) to 19±2 (1.5 MAC). Heart rate changes did not correlate with MAC, and systolic blood pressure correlated in only one of three centers. Intracenter and intercenter analyses failed to demonstrate a significant relationship between lower esophageal contractility and heart rate or systolic blood pressure. No intracenter differences in either amplitude or frequency of lower esophageal contractions were observed, despite differences in volatile agents, induction techniques and agents, patient populations, and duration of anesthesia. Our studies indicate that lower esophageal contractility may be an indicator of anesthetic depth as reflected by MAC, but further studies are needed to quantify the effects of surgical stimulus, intravenous anesthetics, vasodilators, anticholinergics, calcium channel blockers, beta-adrenergic agonists, and the presence of a nasogastric tube.