Ricardo Brandt de Oliveira

Aging, Esophageal Motility, and Gastroesophageal Reflux

OBJECTIVES: To compare esophageal motility and gastroesophageal reflux characteristics in young, middle‐aged, and older healthy volunteers.

A novel biomagnetic method to study gastric antral contractions.

A novel non-invasive method to study the motion associated with gastric antral contractions is discussed. The method is based on magnetic flux changes detected by an a.c. biosusceptometer, produced by a magnetic test meal within the stomach. Measurements are made at the surface of the torso and are easy to perform. Simultaneous measurements were made with electrogastrography and scintigraphy showing remarkable coincidence. The effect of a drug on the amplitude of antral contractions was also assayed with the new method.

Treatment of diabetic gastroparesis with oral clonidine

Background/Aims: Clonidine, a specific alpha‐2‐adrenergic receptor agonist, has been suggested to improve symptoms of gastroparesis in diabetics with diarrhoea. The aim of this study was to investigate the effects of clonidine on gastric emptying and symptoms suggestive of gastroparesis in patients with long‐standing diabetes mellitus and evidence of autonomic neuropathy.

An AC biosusceptometer to study gastric emptying

A simple AC susceptometer was developed to study the gastric emptying when test meals labeled with 10% of a harmless magnetic tracer were ingested. The instrument allows the determination of T 1/2 of the stomach emptying with good precision compared to measurements with gamma camera and 99m Tc in the test meal.

Rat duodenum nitrergic-induced relaxations are cGMP-independent and apamin-sensitive

The effects of the K+ channel blockers, apamin, tetraethylammonium and 4-aminopyridine, upon the relaxations of the isolated rat proximal duodenum induced by nitregic nerve activation, nitric oxide (NO), the NO donor 3-morpholinosydnonimine (SIN-1) and Br-cyclic GMP were determined. The effects of the guanylate cyclase inhibitors, cystamine and N-methylhydroxylamine, on NO-, SIN-1- and nitrergic nerve-induced responses were also investigated. Apamin inhibited nitrergic nerve-, NO-and SIN-1-induced relaxations but did not affect those induced by Br-cGMP. Tetraethylammonium and 4-aminopyridine as well as cystamine and N-methylhydroxylamine failed to affect the relaxations caused by any of the agents tested. These findings indicate that, in the rat proximal duodenum, nitrergic nerve activation as well as exogenous nitric oxide cause relaxation through a cGMP-independent, apamin sensitive mechanism.

Non-antibiotic therapies for Helicobacter pylori infection.

Despite years of experience with Helicobacter pylori treatment, the ideal regimen for treating the infection has not been found. The most effective eradication treatment is the combination of a proton pump inhibitor with antibiotics, but 10–20% of the patients fail to obtain eradication of the infection. Antibiotic resistance is a major factor affecting the outcome of treatment. Non-antibiotic therapies, including phytomedicines, probiotics, and antioxidants, have been increasingly investigated as potential alternatives for the treatment of H. pylori. In this article, we review the non-antibiotic therapies for H. pylori infection.

Diminished retention of food in the proximal stomach correlates with increased acidic reflux in patients with gastroesophageal reflux disease and dyspeptic symptoms.

This work aimed at evaluating the intragastric distribution of food in patients with GERD and dyspepsia and its relationship to acidic reflux episodes. Gastric emptying and food retention in the proximal stomach were evaluated by scintigraphy in 12 healthy subjects and 19 patients with GERD and dyspepsia after a liquid test meal. Patients also underwent 24-hr esophageal pH monitoring, which included a 2-hr postprandial period following a similar test meal. Total gastric emptying was similar in patients and controls, whereas proximal gastric retention (AUCprox/AUCtot) was significantly decreased in patients (mean ± SD: 0.48 ± 0.07 vs. 0.56 ± 0.06; P = 0.02). Within the GERD–dyspepsia group, a significant negative correlation was found between proximal gastric retention and the number of acidic reflux episodes. We concluded that abnormally decreased retention of gastric contents in the proximal stomach after a liquid meal may contribute to the pathogenesis of acidic reflux episodes in patients with GERD and dyspepsia.

Decreased gastric tone and delayed gastric emptying precede neutrophil infiltration and mucosal lesion formation in indomethacin-induced gastric damage in rats.

Gastric antral dysmotility has been implicated in the pathogenesis of indomethacin-induced gastric damage, but the relationship between gastric motor abnormalities and mucosal lesions has not been extensively studied. We investigated whether changes in gastric tone and gastric retention correlate with mucosal lesions and neutrophil migration in indomethacin-induced gastric damage in rats. Indomethacin, either 5 or 20 mg/kg (INDO-5 and INDO-20), was instilled into the stomach, and then gastric damage, neutrophil migration, gastric tone and gastric retention were assessed 1 or 3 h later. Gastric damage was calculated as the sum of the lengths of all mucosal lesions, and neutrophil migration was measured by assaying myeloperoxidase activity. Gastric tone was determined by a plethysmometric method, and gastric retention of either saline or Sustacal was evaluated by a scintigraphic method. Gastric damage was detectable 3 h after either INDO-5 or INDO-20, but not after 1 h. Neutrophil migration was significantly higher 3 h after INDO-20 as compared with INDO-5 or control group, but not after 1 h. Values of gastric tone 1 and 3 h after either INDO-5 (1 h = 1.73+/-0.07 ml; 3 h = 1.87+/-0.03 ml) or INDO-20 (1 h = 1.70+/-0.02 ml; 3 h = 1.79+/-0.03 ml) were significantly lower than in controls (1 h = 1.48+/-0.05 ml; 3 h = 1.60+/-0.06 ml). Gastric retention of saline was higher 1 h after INDO-5 (58.9+/-3.3%) or INDO-20 (56.1+/-3.1%) compared to control (45.5+/-1.7%), but not after 3 h. There were no differences concerning gastric retention of Sustacal between the various groups. Indomethacin induced decreased gastric tone and delayed gastric emptying, which precede mucosal lesion and neutrophil infiltration. These results indicate that there is no relationship between these gastric motor abnormalities and mucosal lesion in indomethacin-induced gastropathy.

Measurement of gastric contraction activity in dogs by means of AC biosusceptometry

The mechanical nature of gastric contraction activity (GCA) plays an important role in gastrointestinal motility. The aim of this study was to detect GCA in anaesthetized dogs, using simultaneously the techniques of AC biosusceptometry (ACB) and manometry, analysing the characteristics of frequency and amplitude (motility index) of GCA, modified by drugs such as prostigmine and N-butyl-scopolamine. The ACB method is based on a differential transformer of magnetic flux and the magnetic tracer works as a changeable external nucleus. This magnetic tracer causes a modification in the magnetic flux, which is detected by the coils. The results obtained from the ACB showed a performance comparable to the manometry in measuring the modifications in the frequency and amplitude of the GCA. We concluded that this ACB technique, non-invasive and free of ionizing radiation, is an option for evaluating GCA and can be employed in future clinical studies.

Abnormal Intragastric Distribution of a Liquid Nutrient Meal in Patients with Diabetes Mellitus

Disordered gastric motility and emptying arewell known complications of diabetes mellitus (DM), butthe pattern of intragastric distribution of food has notbeen extensively studied in diabetics. We examined the partition of a liquid nutrient meal betweenthe proximal and distal stomach and the relationshipsbetween intragastric distribution of food and gastricemptying (GE) and the symptoms in DM patients with and without autonomic neuropathy (AN).Fourteen healthy volunteers and 20 DM patients (13 withAN; 9 with dyspepsia symptoms) ingested a liquidnutrient meal (250 ml; 437 kcal) labeled with[99mTc]phytate. Anterior and posterior serial images of thestomach were taken for 90 min with a gamma camera.Regions of interest for the proximal and the distalhalves of the stomach and for the total gastric areawere defined. Counts from each region along timeallowed estimation of GE and the proportion of activityretained in the proximal stomach after meal ingestion(initial) and throughout GE (mean). GE half-times in controls (median; range: 66 min; 29-90 min)were not significantly different from diabetics (76 min;5->150 min, P > 0.10), but abnormal GE was foundin 11 DM patients (seven delayed and four rapid). In DM patients, initial retention inthe proximal stomach (42%; 16-79% ) was significantlylower (P < 0.02) than in controls (55%; 44-71%). Meanretention in the proximal stomach throughout emptying also was significantly lower (P <0.05) in DM patients (43%; 18-58%) than in controls(51%; 32-69%). There were no differences betweensubgroups of patients with normal, delayed, or rapid gastric emptying regarding mean meal retentionin the proximal stomach. Patients with evidence of AN orwith dyspepsia symptoms had significantly decreasedretention of food in the proximal stomach throughout gastric emptying. We concluded that patientswith diabetes mellitus have abnormally decreasedretention of gastric contents in the proximal stomachafter a liquid meal, which seems to be related to the occurrence of autonomic neuropathy anddyspepsia symptoms, but not to disordered gastricemptying.