Gastric emptying of liquids in rats submitted to acute myocardial infarction

Gastric Emptying (GE) is food transition from the stomach to the upper small intestine. Haemodynamics changes modify gastric emptying and the gastroduodenal motor activity. Myocardial Infarction is a pathological condition in which there are haemodynamics changes. Therefore, the objective of the present investigation was to study the effect of acute myocardial infarction on rat gastric emptying of an isosmotic and inert liquid meal. We conducted a study involving male Wistar rats (varying in body weight from 220 g to 250 g), that were allowed to habituate in a laboratory environment and then divided into 3 groups: group INF, rats in which the myocardial infarction was produced by left anterior coronary artery ligation; group SH, rats in which the myocardial infarction was simulated without ligating the anterior coronary artery; and group NA, rats which were not given any anesthesia or surgical procedures. After group constitution, animals were fasted with access to water ad libitum. 24 hours later, the Gastric Retention (GR) of 1.5 ml/100 g animal weight of a test meal of 0.9% NaCl plus the marker phenol red was evaluated. GE was indirectly evaluated in conscious animals, through determining the percentage of gastric retention (% GR) of a test meal, measured 10 minutes after orogastric infusion. Results of the present study showed that animals from the INF group presented GR (median=48.0%), significantly higher than the NA group (30.6%) and SH group (36.6%). No statistical difference in GR was observed between the SH and NA groups. Infarcted area, expressed in percentages, in animals of the INF group was 51.3+/-4.7% (mean SEM, N=17) which not presented correlation with results of GR of the same group (r=-0.05). From a caloric viewpoint, the results suggested that acute myocardial infarct in rats induce delay of the gastric emptying of an isosmotic and inert liquid meal.     

Gastric emptying of solids but not liquids is decreased in rats with chronic renal failure

Severe gastric complications occur in uremic patients, yet few studies have addressed the effect of chronic renal failure (RF) on gastric physiology. In the present study, we investigated: (1) the effect of RF on gastric emptying of liquids and solids in awake rats, (2) the motor function in the gastric corpus, and (3) the role of nitric oxide in any alterations in gastric motor function in uremic rats. RF was induced by partial kidney infarction. RF had no effect on gastric emptying of liquids but significantly inhibited gastric emptying of solids by 68%.N-Nitro-l-arginine, an inhibitor of nitric oxide (NO) synthesis, had no effect on the reduced gastric emptying of solids in RF rats. RF rats showed an altered pattern of gastric motility compared to sham-operated rats. These data suggest that RF induced an inhibition of gastric emptying of solids, but not liquids. However, NO does not seem to play a role in this inhibition.This work was supported by NIH grant DDK 41004 (H.E.R.) and the CURE/UCLA Digestive Disease Core Center DDK 41031 (Animal and Gastrointestinal Blood Flow Cores). E.Q. was the recipient of a Fogarty International Fellowship Award (NIH 1 FO5 TWO4443-01) and a grant from the Conserja de Education, Cultura y Deportes of the Canary Islands Autonomous Government. J.B. was supported by a grant from Fondacio La Caixa, Spain.     

Gastric secretion and emptying of liquids in reflux esophagitis

We have investigated the gastric secretory activity and the emptying half-time of a liquid meal in 17 selected patients with reflux esophagitis compared to 10 controls. The basal acid output and the basal and maximal secretory volume were higher in the patient group (P<0.05,P=0.05, andP<0.01, respectively), while the maximal acid output and the basal and maximal acid concentration were not different in the two groups. The gastric emptying half-time of a liquid meal was higher in the patient group (P<0.001). Our results show that gastric function may be altered in reflux esophagitis patients and suggest particularly that a delayed emptying of liquids may play a role in the pathogenesis of the disease in some patients.     

Gastric emptying in rats with chronic gastric fistulas

A technic for studying gastric emptying using phenol red test meals in rats with chronic gastric fistulas was shown to yield valid and reproducible data. This method has the advantage of utilizing a chronic, unanesthetized, unrestrained animal, which may also be used to study gastric secretion. The test meal technic described here is a more sensitive detector of anticholinergic inhibition of gastric motor activity than either intragastric balloon recordings or gastric emptying methods using pellets rather than a liquid meal.     

Gastric emptying in patients with chronic renal failure receiving hemodialysis

Patients with renal failure requiring hemodialysis often suffer from nausea and vomiting. Gastric emptying has not been studied in these patients. To determine whether an abnormality of gastric emptying might account for symptoms in these patients, two groups of ten patients each were selected, one group with symptoms of nausea and vomiting and another without symptoms. Autonomic function was assessed in all patients. Fluid and solid gastric emptying rates were quantified utilizing a dual radionuclide technique. Half-emptying times for fluid and solid test meals were not statistically different from previous standards derived using the same methods in a normal population. Patients with chronic renal failure receiving hemodialysis have no demonstrable abnormality in gastric emptying, whether symptomatic or not.     

阿托伐他汀对肾功能不全大鼠造影剂诱导的急性肾小管损伤的保护作用

目的探讨非离子低渗造影剂碘海醇对轻度肾功能不全大鼠肾小管的急性损伤作用,以及不同剂量的阿托伐他汀对肾小管损伤的保护作用。方法 36只轻度肾功能不全模型大鼠随机分为模型组、碘海醇组、阿托伐他汀小剂量组(小剂量组)、阿托伐他汀大剂量组(大剂量组),每组9只。另选9只为假手术组。注射后24、72h、7d每组监测血尿素、肌酐、尿液中肾损伤分子1(KIM-1)、N-乙酰-β-D-氨基葡萄糖苷酶(NAG)水平,HE染色观察肾小管结构变化,并计算肾小管损伤危险评分,TUNEL染色检测肾小管细胞凋亡率。结果与模型组比较,碘海醇组72h尿素、各时间点肌酐、KIM-1、NAG、肾小管损伤危险评分、细胞凋亡率明显升高(P<0.05,P<0.01);与碘海醇组比较,大剂量组24h、7d肌酐明显降低(P<0.05),各时间点KIM-1、NAG、肾小管损伤危险评分、细胞凋亡率明显降低(P<0.01)。结论在肾功能不全基础上注射低渗造影剂碘海醇能够对肾小管产生急性损伤作用,造影剂注射前连续给予阿托伐他汀能减轻该损伤,并且大剂量阿托伐他汀该保护作用更强。     

Gastric emptying of liquids and solids in the portal hypertensive rat

The effects of portal hypertension on gastric motor function were investigated using the rat staged portal vein ligation model. Gastric emptying of liquids and solids was studied separately following meals labeled with 51Cr or 99Tc by whole stomach scintillation counting. Portal hypertension was consistently established in experimental rats (splenic pulp pressure: mean +/- SEM, portal hypertension versus control, 16.8 +/- 0.7 vs 11.8 +/- 0.7 mm Hg, P less than 0.0001). Although liquids were emptied in an exponential manner and solids in a linear fashion, gastric emptying of both meals was more rapid in the experimental rats. Ten minutes after the liquid meal, more than 50% of the meal had emptied from the stomachs of portal hypertensive rats while only one third of the meal had cleared in the control group (P less than 0.02). Gastric emptying of the solid meal was significantly accelerated in experimental rats at 60 and 120 min (percent meal remaining: portal hypertension versus control, 41.9 +/- 4.0 vs 55.4 +/- 3.5 and 21.5 +/- 4.9 vs 32.6 +/- 4.3, P less than 0.05). Stomachs of portal hypertensive animals were heavier (P less than 0.009) and histologic examination revealed submucosal edema. Thus, a possible mechanism of the disrupted gastric motor function in portal hypertension is decreased gastric wall compliance secondary to edema.     

Gastric emptying for liquids and solids after distal gastrectomy with Billroth-I reconstruction

BACKGROUND/AIMS: Although distal gastrectomy followed by Billroth-I reconstruction has been a standard surgical procedure for over 100 years, gastric emptying of liquid and solids after this procedure remains poorly understood, despite its contribution to postgastrectomy complications such as dumping syndrome and reflux esophagitis. A simple way to standardize measurement and generate normal values is needed. This study proposed a new, accurate and easy method, "dual phase method", for gastric emptying after distal gastrectomy. METHODOLOGY: Liquid- and solid-phase gastric emptying were measured using a combined test consisting of acetaminophen and sulfamethizole capsule ingestion, respectively. Data from 12 patients (B-I group) who had undergone distal gastrectomy with D2 lymph node dissection and truncal vagotomy followed by Billroth-I reconstruction were compared with those from 14 healthy volunteers (control group). RESULTS: A two-factor repeated measures ANOVA (analysis of variance) demonstrated a highly significant difference in the sequential changes in the serum acetaminophen concentration after ingestion between the two groups (p<0.0001). On the other hand, the sequential changes in the serum sulfamethizole concentration after ingestion was similar in the two groups (p=0.91). CONCLUSIONS: Gastric emptying of liquids is rapid after distal gastrectomy followed by Billroth-I reconstruction. However, emptying of solids is unchanged. The data obtained in this study can be a point of reference for comparing gastric emptying following gastrectomy.     

Gastric emptying and small intestinal mucosal injury in rats.

A technique was developed to produce small intestinal mucosal injury in vivo by perfusing the mid-small intestine of rats with HCl, NaOH, FeSO4, and AgNO3. Three hours following injury, gastric emptying and small intestinal transit were measured by examining the gastrointestinal distribution of a non-absorbable radioisotope which had been placed in the stomach for 1 hour. There was a strong association between the villus injury produced by various concentrations of the injurious agents and the degree of gastric retention. Necrosis of villus tips, as produced by AgNO3, was sufficient to cause marked gastric retention. Injury to the small intestinal mucosa of one parabiotic rat did not produce gastric retention in the partner. It is concluded that injury to small intestinal villi is sufficient to induce gastric retention and that the effect is most likely nerve-mediated.     

Gastric emptying of liquids in normal subjects and patients with healed duodenal ulcer disease

We have characterized the dose-response of inhibition of gastric emptying by acid, glucose, and fat in duodenal ulcer (DU) patients and normals (N) matched by age and sex. Gastric emptying was measured by the George technique while intragastric pH was maintained constant by intragastric titration. Acid, glucose, and fat inhibited gastric emptying in a dose-dependent fashion in both groups. DU patients emptied all three types of meals faster than normals, but differences were only seen at the lower doses of glucose or with the less potent doses of acid and fat. With low concentrations of glucose and at all concentrations of acid, DU patients emptied the meals faster than normals only in the first 5 min; but with fat the differences persisted throughout the 30-min test. Differences in gastric emptying of liquid meals in DU patients vs normals are small, and they occur with nutrient as well as acid meals. The variable responses obtained with the different concentrations may explain the inconsistencies found by other workers.     

Gastric emptying of liquids after highly selective vagotomy for duodenal ulcer

In a group of clinical patients with duodenal ulcer submitted to highly selective vagotomy, gastric emptying studies were performed pre-operatively and 2 weeks and 6 months after surgery. A standard liquid meal labeled with radioactive technetium was used for scanning. In this group of duodenal ulcer patients, no abnormal emptying was noted prior to surgery as compared with controls. After highly selective vagotomy, the gastric emptying time for liquids was statistically shorter as compared with preoperative values. It is concluded that highly selective vagotomy may be the operative treatment of choice for duodenal ulcer patients with respect to acid secretion, but that it alters gastric motility and emptying significantly.     

Gastric emptying of liquid in children suffering from acute rotaviral gastroenteritis.

Nausea and vomiting commonly occur in children suffering from rotaviral diarrhoea. Gastric emptying was studied in 10 children (age six to 12 months) suffering from acute diarrhoea caused by rotavirus using a dye dilution double sampling technique. The test meal was 5% dextrose in water and this test was repeated 12 weeks after recovery. The median (range) of the percentages of the liquid meal remaining in the stomach at 5, 10, 20, 40, and 60 minutes after instillation of the meal were 82 (79-90), 70 (61-86), 51 (38-76), 26 (14-53), and 13 (2-35) respectively in the acute stage, whereas after the recovery period the values were 76 (70-79), 58 (49-63), 33 (24-40), 11 (2-26), and 3 (0-7). The differences were statistically significant. The half time of gastric emptying (t1/2) was 19.5 (14-30) minutes in acute stage, and 13.1 (10-15) minutes during follow up (p less than 0.01). Rotaviral gastroenteritis is accompanied by abnormal gastric motor function, as manifested by delayed emptying of a liquid meal.     

Gastric emptying in chronic renal failure patients on hemodialysis

We studied gastric emptying of solid food, using a radionuclide technique, in 18 patients with chronic renal failure patients on hemodialysis: nine with nausea and vomiting or postprandial bloating and nine without. Both groups were compared with a group of normal subjects. Gastric emptying was consistent with a linear elimination in all groups. The regression coefficients of the symptomatic, asymptomatic, and control groups were -0.48 +/- 0.1%, -0.5 +/- 0.14%, and -0.58 +/- 0.15% min, respectively. These were not statistically different. Half-emptying times were 116.4 +/- 7.1 min, 97.8 +/- 13.7 min, and 98.7 +/- 5.6 min, respectively. These also were not statistically different. Values of percentage retention at 2.5 hours for the same groups were 31.6 +/- 5, 24.8 +/- 6.4, and 18.6 +/- 4.4, respectively, again with no statistical difference. Patients with chronic renal failure on hemodialysis, symptomatic or asymptomatic, have no obvious impairment of gastric emptying of solids.     

Gastric emptying of oral rehydration solutions in acute cholera

Gastric emptying of rice powder electrolyte solution and of glucose electrolyte solution was measured by a marker dilution double sampling technique in 14 and in 16 adult patients respectively after intravenous rehydration during an attack of acute cholera. Six patients who received rice powder electrolyte solution and seven who received glucose electrolyte solution re-attended for a repeat study with the same test meal 16 days later, when fully recovered from cholera. No differences in gastric emptying patterns of the two electrolyte solutions were observed, either in the acute or in the recovered patients. Similarly, gastric emptying of both solutions was rapid during acute cholera and comparable to that observed in recovered patients. This study indicates that gastric emptying is not impaired in acute cholera and that the rate of emptying of oral rehydration solutions is adequate to account for their observed clinical efficacy in fast purging patients with acute cholera.     

Gastric emptying in marathon runners.

Radionuclide gastric emptying studies using 99m-Tc human serum albumin egg omelette have been carried out in 10 long distance runners at rest and during a 90 minute run at sustained speed. Resting values are compared with controls comprising 10 sedentary subjects. Runners show a significantly accelerated basal gastric emptying (runners t 1/2 = 67.7 (5.9) min; sedentaries t 1/2 = 85.3 (4.5) min, p less than 0.001). The exercise had no significant effect on gastric emptying in these trained subjects (exercise t 1/2 = 66.8 (5.9) min, p = NS), suggesting adaptation to exercise.     

Gastric emptying of solids in man.

The influence of the type and size of solid particles on their emptying from the stomach was studied using isotopically labelled chicken liver and inert particles in normal subjects and in patients who had undergone gastric surgery. In normal subjects, initial emptying of the liver was slower than that of inert particles both for large liver cubes (1 cm) and small cubes (0.3 cm). Liver emptying subsequently accelerated to be faster than emptying of the inert particles. Overall emptying of the liver given as small cubes was faster than large cubes; 50% emptied in 50 minutes and 70 minutes respectively. In the postoperative subjects, emptying of the liver and of the inert particles was identical. The findings are consistent with the hypothesis that solid foods such as liver are ground down and 'liquified' by the action of gastric peristalsis before being discharged to the duodenum. Ingested particle size appears to influence the rapidity of this process, which should be distinguished from the propulsive function of the stomach where small solid particles are concerned.     

Gastric acid secretion and gastric emptying of liquids in 99 male duodenal ulcer patients

Gastric acid hypersecretion and accelerated gastric emptying are commonly considered as possible determinants of duodenal ulcer, but the relative frequencies of these gastric dysfunctions have never been evaluated in a homogeneous group of patients. We studied basal and pentagastrin-stimulated gastric acid secretion and gastric emptying of a radiolabeled caloric liquid meal in 99 consecutive male patients with endoscopically proven, active, uncomplicated duodenal ulcers. Compared to matched healthy subjects, ulcer patients presented increased basal and stimulated acid secretion (P<0.001).Sixty-nine patients had peak acid output values above the 95% confidence limits of the control population (14.2–30.6 meq/hr).Cigarette smoking was correlated with gastric acid hypersecretion. No significant difference was found between duodenal ulcer patients and controls in mean gastric emptying times. Ulcer patients showed a greater variance of gastric acid secretion and emptying values than healthy subjects. This reflects varied gastrointestinal function among ulcer patients. No significant correlation was found between gastric acid output and gastric emptying times. These findings suggest that gastric acid hypersecretion, but not accelerated gastric emptying of liquids, play a relevant role in the pathogenesis of duodenal ulcer.