From gastric inflammation to gastric cancer

The majority of gastric adenocarcinomas are related to chronic inflammation induced by Helicobacter pylori infection. For intestinal-type gastric cancer, a multistep process of mucosal alterations leading from gastritis via glandular atrophy, intestinal metaplasia and dysplasia to invasive carcinoma is well recognized. Ongoing clinical studies focus on a 'point of no return'. It is defined as a situation when certain alterations are no longer reversible by H. pylori eradication and progression to gastric cancer may continue. H. pylori affects the mucosal as well as the systemic immune response by secretion of cytokines and the recruitment of distinct inflammatory cells. The immune response is characterized by a balance between a Th1-dominated response and the recruitment of antigen-specific regulatory T cells that allow the bacteria to persist in human gastric mucosa. Besides immune-mediated effects, H. pylori induces cellular alterations as well as genetic alterations in genes that are essential for the epigenetic integrity and mucosal homeostasis. These genetic alterations during gastric cancer development are in focus of intensive research and should ultimately allow the identification of risk factors involved in gastric carcinogenesis. The detection of individuals at high risk for gastric cancer would help to design appropriate strategies for prevention and surveillance.     

Control of gastric emptying by gastric tone

During ingestion of food, the stomach relaxes to accommodate the meal and, subsequently, a progressive gastric contraction parallels gastric emptying. Intestinal nutrients trigger feedback relaxatory mechanisms that regulate gastric tone and, hence, the nutrient load delivered into the small intestine. This regulation of gastric tone is mediated, at least in part, via the vagus. Defective gastric tone is associated with impaired gastric emptying, as seen in patients with postsurgical gastroparesis. However, increased intragastric pressure, corresponding with defective gastric accommodation, induces abdominal symptoms, but does not alter the gastric emptying pattern. These data indicate that gastric emptying is controlled by complementary mechanisms: gastric tone exerts an emptying force, but gastric outlet resistance is also an important regulator.     

胃起搏对胃动力紊乱犬胃排空及胃肌电活动的影响

目的　研究胃起搏对胃动力紊乱犬胃排空及胃电参数的影响。方法　采用双侧迷走神经干切断术联合应用胰高血糖素建立胃动力紊乱犬模型 ;采用 4导联胃肠电系统微机分析仪记录胃肠浆膜肌电活动 ;99mTc 植酸钠标记的半固体试餐 ,单光子计算机断层显像技术 (SPECT)检测胃半排空时间(GEt1/ 2 ) ;采用适宜起搏参数从胃体、胃窦在腹部投影部位输入起搏信号驱动胃电节律。结果　迷走神经干切断术后犬的GEt1/ 2 为 (79.4 2± 1.91)min ,较术前 (5 6 .35± 2 .99)min明显延迟 (P <0 .0 0 1) ,但行胃起搏治疗后GEt1/ 2 为 (6 4 .94± 1.75 )min ,较治疗前明显加快 (P <0 .0 0 1) ;胃起搏治疗前迷走神经干切断犬餐后的胃电频率为 (0 .0 81± 0 .0 0 7)Hz、胃电幅度为 (2 .32± 0 .35 )mV、慢波的传播速度为 (4 .0 6± 0 .4 0 )cm/s ,均较正常对照犬显著降低 [(0 .0 90± 0 .0 0 6 )Hz ,(4 .2 5± 0 .12 )mV ,(6 .92± 0 .2 4 )cm/s,(P <0 .0 5 ) ],治疗后其餐后胃电频率 (0 .0 92± 0 .0 0 5 )Hz、胃电幅度 (3.97± 0 .19)mV和慢波的传播速度 (5 .5 7± 0 .4 8)cm/s均明显高于治疗前 (P <0 .0 5 )。结论　采用适宜起搏参数输入起搏信号可完全触发胃电慢波 ,改善胃电参数 ,纠正药物导致的异常胃电节律 ,加速胃排空 ,恢     

Observations on benign gastric ulcer simulating gastric carcinoma

We have re-evaluated over-diagnosed cases which were first diagnosed, pre-operatively, as gastric cancer yet later confirmed as benign lesion (excavated lesion, in particular) in the post-operative histological examination of resected stomachs. We have experienced a total number of 1,358 cases which, being detected through mass survey, were diagnosed as cancer and, consequently, operated upon. On the other hand, 61 benign cases were misdiagnosed as cancer, 28 cases being protruded lesions and 33 cases excavated lesions. Among the misdiagnosed cases of excavated lesions, 27 cases were gastric ulcers or their scars, the remaining 6 cases being gastritis or gastric erosion. In 22 out of 33 cases of misdiagnosis, the wrong diagnosis was made by relying solely upon X-ray and endoscopy. Even after the addition of cytology, there were still 9 cases of misdiagnosis. Since, however, biopsy was introduced, there have been only 2 cases of wrong diagnosis. We may safely say that through these findings the absolute necessity of biopsy for the attainment of an accurate diagnosis of early gastric cancer has been sufficiently attested.     

The relationship between gastric microbiota and gastric disease

Traditionally, the stomach was believed to be a sterile organ unsuitable for microbiota growth. However, the discovery of H. pylori subverted this conception. With the development of molecular techniques, an abundance of microbiota of great diversity was found in the stomach. In addition, various lines of evidence suggest that the gastric microbiota plays a critical role in the development and progression of the gastric disease.The gastrointestinal microbiome plays an important role in various physiologic and pathologic processes.     

胃微生态与胃癌的研究进展

胃微生态平衡是人体健康的重要前提,幽门螺杆菌(Helicobacter pylori,Hp)是目前已发现的与胃癌相关的关键病原体之一,普遍存在于人胃黏膜上皮。Hp感染可引起胃内其他菌群的改变,还可引起长期慢性的胃黏膜损伤,导致一系列胃黏膜上皮恶性进展和胃癌的发生。本文就胃微生态与Hp感染的关系、Hp感染在胃癌发生中的作用、胃内其他菌群在胃癌发生中的作用及微生态制剂在胃癌治疗的作用进行综述。进一步揭示Hp感染对胃微生态平衡的影响,胃微生态平衡和Hp感染在胃癌发生发展中的作用及微生态制剂在胃癌治疗中的意义。     

Human gastric myoelectric activity and gastric emptying following gastric surgery and with pacing.

Postoperative gastric myoelectric activity, gastric emptying, and clinical course were correlated in 17 patients at high risk of developing gastroparesis after gastric surgery. In addition, an attempt was made to pace the stomach with an electrical stimulus and determine the effect of pacing on early postoperative gastric emptying. Gastric dysrhythmias (bradygastria, slow wave frequency < 2 cycles/min; tachygastria, slow wave frequency > 4 cycles/min) persisted beyond the first postoperative day in 6 patients (35%). Delayed gastric emptying was identified by a radionuclide meal in 15 patients (88%), but symptoms of gastroparesis developed in only 6 of 15 (40%). Patients with postoperative gastroparesis had more frequent dysrhythmias than asymptomatic patients (67% vs. 18%), but these differences were not significant, although we cannot exclude a type II statistical error. Gastric rhythm was entrained in 10 of 16 patients (63%). Pacing increased the gastric slow wave frequency (3.1 vs. 4.1 cycles/min; P < 0.01) but did not improve gastric emptying (gastric retention at 60 minutes, 86% +/- 6% for control and 90% +/- 2% for paced). In conclusion, gastric dysrhythmias do not appear to play a major role in the development of postsurgical gastroparesis. Although gastric rhythm could be entrained in the majority of patients, pacing did not improve gastric emptying overall.     

Pedunculated gastric carcinoma demonstrating a gastric foveolar phenotype

We report a case of gastric cancer complicated with very well differentiated adenocarcinoma containing signet ring cells. An endoscopic examination revealed a pedunculated polyp in the fornix of the stomach. A surgical operation was performed and the pathological findings showed very well differentiated adenocarcinoma mimicking gastric foveolae with a poorly differentiated component containing signet ring cells. This is the first case of pedunculated gastric cancer complicated with very well differentiated adenocarcinoma containing signet ring cells and also demonstrating a gastric foveolar phenotype.     

Relationship between gastric mucosal hemodynamics and gastric motility

Continuous measurement of gastric mucosal hemodynamics (the index of mucosal hemoglobin concentration, the index of oxygen saturation and blood flow) in rats showed oscillatory changes. The mechanism of the oscillations was investigated using a probe specially designed for simultaneous measurement of hemodynamics and intragastric pressure. A hemodynamics-measuring probe for either reflectance spectrophotometry or laser-Doppler flowmetry was tied to a pressure microtransducer, inserted through an incision in the forestomach, and brought into gentle contact with the corpus mucosa. Synchronous oscillatory changes (4-6 cycles/min) in hemodynamics and motility were observed in the resting state (mean blood pressure: 120 mmHg). During moderate hemorrhagic hypotension (mean: 81 mmHg), oscillations in the hemodynamics increased in both amplitude and frequency, while motility remained constant. Oscillations in the hemodynamics were also affected by fluctuations in blood pressure and by topical application of norepinephrine to the corpus serosa. In water-immersion restraint rats, changes in the oscillations in the hemodynamics and motility were virtually synchronous; frequency decreased and amplitude increased. These findings suggest that oscillatory changes in gastric mucosal hemodynamics are regulated not only by gastric motility but also by arteriolar vasomotion of the gastric wall.     

Endoscopy,gastric ulcer,and gastric cancer

The practice of following benign-appearing gastric ulcers until healing was critically evaluated in a retrospective manner by reviewing all gastric ulcers that were followed with serial endoscopy and all gastric cancers diagnosed at the University of Alabama at Birmingham. The stated purpose of following ulcers to healing is to detect those gastric cancers that may be masquerading as benign ulcer and were not correctly diagnosed at initial endoscopy. Over a five-year period, 148 gastric ulcers were followed with serial endoscopy and in no case was an unsuspected carcinoma found at follow-up endoscopy. In addition, of 67 gastric cancers diagnosed between 1979 and 1986, 62 were suspected of being malignant by the endoscopist at initial examination for an accuracy of 92%. The accuracy rate based solely on biopsy and/or brush cytology was 94%. When endoscopic and biopsy and/or cytology impressions were combined, only one case of gastric carcinoma was not suspected. The overall accuracy was 99%. These results suggest that if either the endoscopic impression or the biopsy and cytology is suspicious for malignancy, then follow-up endoscopy until healing should be done. On the other hand, if, at the initial examination, the ulcer appears benign and biopsy plus cytology are negative, then serial endoscopy has a low benefit relative to its cost.     

The role of gastric microbiota in gastric cancer

ABSTRACT

Gastric cancer represents one of the leading causes of cancer deaths worldwide. Helicobacter pylori (H. pylori) infection is the strongest risk factor associated with gastric cancer. Due to new molecular techniques allowing greater identification of stomach microbes, investigators are beginning to examine the role that bacteria other than H. pylori play in gastric cancer development. Recently, researchers have investigated how the composition of the gastric microbiota varies among individuals with various stages of gastric disease. Specific microbes residing in the stomach have been preferentially associated with gastric cancer patients compared to individuals with a healthy gastric mucosa. Studies conducted on the insulin-gastrin (INS-GAS) transgenic mouse model have provided additional insight into the association between the gastric microbiota and gastric cancer. The purpose of this article is to review the current state of literature on the relationship between the gastric microbiota and gastric cancer based on clinical studies performed to date.     

Relationship between gastric mucosal hemodynamics and gastric motility

Continuous measurement of gastric mucosal hemodynamics (the index of mucosal hemoglobin concentration, the index of oxygen saturation and blood flow) in rats showed oscillatory changes. The mechanism of the oscillations was investigated using a probe specially designed for simultaneous measurement of hemodynamics and intragastric pressure. A hemodynamics-measuring probe for either reflectance spectrophotometry or laser-Doppler flowmetry was tied to a pressure microtransducer, inserted through an incision in the forestomach, and brought into gentle contact with the corpus mucosa. Synchronous oscillatory changes (4-6 cycles/min) in hemodynamics and motility were observed in the resting state (mean blood pressure: 120 mmHg). During moderate hemorrhagic hypotension (mean: 81 mmHg), oscillations in the hemodynamics increased in both amplitude and frequency, while motility remained constant. Oscillations in the hemodynamics were also affected by fluctuations in blood pressure and by topical application of norepinephrine to the corpus serosa. In water-immersion restraint rats, changes in the oscillations in the hemodynamics and motility were virtually synchronous; frequency decreased and amplitude increased. These findings suggest that oscillatory changes in gastric mucosal hemodynamics are regulated not only by gastric motility but also by arteriolar vasomotion of the gastric wall.