Periodontal status and pathogenic bacteria after gastric bypass: a cohort study.

AIM: The aim this study was to evaluate the influence of gastric bypass surgery (GBS) on periodontal disease and quantify the periodontopathogenic bacteria in patients undergoing this surgery. MATERIAL AND METHODS: This prospective study was composed of 50 patients who underwent bariatric surgery and the data collection was performed in three periods pre-operative, 6 (6M) and 12 months (12 M) postoperative. The oral clinical examination to assess periodontal disease; gingival fluid sample collection for quantification of the periodontopathogenic bacteria Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Prevotella intermedia using q-PCR; body mass index (BMI) and for collection of the individual's health-related data from medical files. RESULTS: There was a significant reduction in serum C-reactive protein (CRP) and glucose levels after surgery. The mean probing pocket depth (PPD) and clinical attachment level (CAL) increased significantly in the postoperative period of 6 months (p = 0.001). In the same period, the amount of P. gingivalis increased (p = 0.028) and the other bacteria decreased slightly (p > 0.050). In the presence of P. gingivalis, T. forsythia, T. denticola and P. intermedia, a poor periodontal condition was observed. CONCLUSION: The periodontal disease increased in severity and P. gingivalis increased after GBS. A systemic inflammation resolution due to bariatric surgery in obese subjects does not seem to affect the course of periodontal disease.

Impact of bariatric surgery on oral health conditions: 6-months cohort study.

OBJECTIVES: We evaluate oral health conditions before and after bariatric surgery. METHODS: The sample was composed of 59 patients who had undergone Roux-en-Y gastric bypass (RYGB). Salivary flow, periodontal pocket depth and dental wear were evaluated before and after 6 months of surgery. Body mass index (BMI), C-reactive protein (CRP) and glucose levels were obtained from the patient's medical files. A t-test was used for dependent samples. RESULTS: The mean BMI decreased from 49.31 ± 8.76 to 35.52 ± 8.12 kg/m(2) in 6 months after surgery (P < 0.000). Before surgery, 67% of patients had high levels of CRP and 38% higher blood glucose levels and after surgery there were significant reductions in these levels (P < 0.001). Salivary flow ranged from 0.84 to 0.95 ml/min. There was increased prevalence of periodontal pockets (P = 0.022) and mean pocket depth increased to about 0.5 mm (P < 0.001). The percentage of surfaces with dental wear in dentine was significantly higher after bariatric surgery (P = 0.002), while dental wear in enamel decreased (P = 0.019). CONCLUSIONS: Bariatric surgery may improve systemic conditions. However, it had a negative impact on oral health conditions because of an increase in periodontal disease and dental wear.

Early identification of infectious complications in bariatric surgery by the determination of peritoneal and systemic cytokines.

BACKGROUND: Obesity has become a global epidemic and bariatric surgery is one of the therapeutic tools to deal with it. Postoperative complications can occur, such as staple line dehiscence and anastomotic leaks, leading to increased patient mortality. The diagnosis of these complications is frequently difficult. The objective of the present study was to determine whether peritoneal and systemic cytokines could early detect those complications. METHODS: All patients who underwent open Roux-en-Y gastric bypass from February 2007 to August 2008 were prospectively evaluated. Blood and peritoneal effluent from the drain were collected for the determination of cytokine levels. We also evaluated the clinical signs and the leukograms of the patients. RESULTS: A total of 107 obese patients were studied. Ninety patients had no complications; 17 had at least one infectious complication which include five cases of staple line dehiscence. Until the third postoperative day, the vital signs and the leukogram did not predict the onset of infectious complications, but the cytokines (interleukin-1beta and interleukin-6) were early markers of these complications. CONCLUSION: Cytokines are good predictors of poor postoperative evolution in bariatric surgery since peritoneal cytokines diagnose better these infectious complications even before changes in blood count and before the occurrence of clinical manifestations.

Intestinal bacterial overgrowth after Roux-en-Y gastric bypass.

The aim of the present study was to report the occurrence of serious subnutrition, associated to intestinal bacterial overgrowth, in two patients submitted to bariatric surgery. Two female patients (body mass index, 49 and 50 kg/m(2), respectively) were submitted to Y-en-Roux gastric bypass. The first patient evolved a 52% loss of body weight within 21 months after surgery; the other, a 34% loss of initial body weight within 15 months after surgery, results corresponding, respectively, to 62 and 45 kg weight losses. However, both patients reported asthenia, hair fallout, and edema, and one also reported diarrhea, but none was feverish. Their respective albuminemias were of 24 and 23 g/l. A respiratory hydrogen test suggested bacterial hyperproliferation. Thirty days after ciprofloxacin and tetracyclin treatments, they showed improved albumin levels and nutritional states, both confirmed by results of hydrogen breath tests. Bacterial overgrowth is an important complication that can compromise clinical evolution of patients submitted to intestinal surgery like gastroplasty with Y-Roux anastomosis. In cases of clinical suspicion or a confirmed diagnosis, adequate antibiotics, sometimes requiring to be cyclically repeated, should be administered.

Treatment of gastrogastric fistula after Roux-en-Y gastric bypass: surgery combined with gastroscopy.

A 53-year-old male who had previously undergone an open gastric bypass (Capella-Fobi) developed a gastrogastric fistula during the late postoperative course. Because he regained weight and had a stomal ulcer difficult to control, it was decided to submit him to revisional surgery. At laparotomy, a retrogastric approach plus gastroscopy permitted easy identification and closure of the fistula. The patient is doing well and losing weight after this reoperation.

Weight loss after bariatric surgery and periodontal changes: a 12-month prospective study.

BACKGROUND: Several longitudinal studies have explored the association of obesity and weight gain with periodontal disease. However, the effect of weight loss on periodontal tissues remains unclear. OBJECTIVE: To explore whether weight loss after bariatric surgery was associated with changes in periodontal measures over 12 months. SETTING: Two public hospitals in São Paulo, Brazil. METHODS: We used data from 110 morbidly obese patients (body mass index [BMI]>40 kg/m2 or≥35 kg/m2 with co-morbid conditions) who underwent bariatric surgery between April 2011 and March 2013. Data on demographic factors, BMI, smoking habits, and glucose levels were extracted from medical records preoperatively and after 6 and 12 months postsurgery. A full-mouth periodontal examination was conducted by trained examiners to assess probing pocket depth, clinical attachment loss, and bleeding on probing (BOP) at baseline and 6 and 12 months after surgery. Data were analyzed using linear mixed-effects models. RESULTS: BMI was not significantly related to the proportion of sites with BOP at baseline, but it was negatively associated with the rate of change in the proportion of sites with BOP. The greater the BMI loss, the higher the proportion of sites with BOP, particularly 6 months after surgery. However, BMI was not associated with baseline probing pocket depth and clinical attachment loss or rates of changes in these periodontal outcomes. CONCLUSION: The findings suggest that weight loss was associated with increased gingival bleeding, showing a peak at 6 months after bariatric surgery. Periodontal pocketing and attachment loss remained unchanged during the study period.

Duodenum inclusion in alimentary transit for preventing or correcting nutritional deficiencies resulting from Roux-en-y gastric bypass in obesity treatment.

Nutritional and metabolic complications can develop after Roux-en-Y gastric bypass (RYGB) when there is an exaggerated response to the anatomical and functional changes or when there is inadequate nutritional supplementation. Severe malnutrition is rare, but deficiencies of vitamin B12, iron, calcium and thiamin, metabolic bone disease and gallstones are common after RYGB. Shortage of vitamin B12, iron, calcium and also cholelithiasis are caused at least partially by excluding the duodenum and proximal jejunum from food transit. We designed a new procedure, with the maintenance of the duodenum and proximal jejunum in the gastrointestinal transit through interposition of jejunal loop, as a primary operation to prevent such deficiencies or as corrective surgery for severe malnutrition after RYGB with failure in responding to conservative treatment. Complicações nutricionais e metabólicas podem se desenvolver após a derivação gástrica em Y de Roux (DGYR) quando há uma resposta exagerada às mudanças anatômicas e funcionais ou quando há suplementação nutricional inadequada. A desnutrição grave é rara, mas deficiências de vitamina B12, ferro, cálcio e tiamina, doença óssea metabólica e cálculos biliares são comuns após a DGYR. Dessas deficiências mencionadas, a de vitamina B12, de ferro, de cálcio e também a colelitíase, são causadas, ao menos parcialmente, pela exclusão do duodeno e jejuno proximal. Um novo procedimento com a manutenção do duodeno e do jejuno proximal no trânsito gastrointestinal, mediante interposição de alça jejunal, foi idealizado como operação primária para prevenir essas deficiências ou como cirurgia corretiva de desnutrição grave após DGYR com falha na resposta a exaustivas tentativas de tratamento conservador.

A new revisional surgery for severe protein-calorie malnutrition after Roux-en-Y gastric bypass: successful duodenojejunal reconstruction using jejunal interposition.

Roux-en-Y gastric bypass (RYGB) may result in nutritional deficiencies, mainly involving micronutrients, and occasionally protein-calorie malnutrition (PCM) because of the resulting anatomic and functional changes. Failure of conservative PCM treatment may be an indication for corrective surgery, where the technique may vary according to the surgical cause of the malnutrition. In this study, we present the results of the reconnection of the duodenum and the proximal jejunum to the alimentary tract for the treatment of severe PCM caused by malabsorption after RYGB.

Presence of Serum Ferritin before and after Bariatric Surgery: Analysis in Dentate and Edentulous Patients.

Society has changed its own lifestyle, specially its eating habits and physical activities, leading to excessive weight and a sedentary behavior, which has contributed to obesity increase. Bariatric surgery is the most effective treatment to obesity, allowing weight loss and its maintenance. However, it has been related high levels of iron deficiency after surgery. A person's nutritional status might be affected by total or partial tooth loss. The aim of this longitudinal prospective cohort study was to evaluate the levels of serum ferritin before and after bariatric surgery and to identify if there is a relation with tooth loss. The sample was composed of 50 patients selected and assisted at Amaral Carvalho Hospital, located in Jaú city, Brazil. The use and necessity of prosthesis, dental absence or presence, and serum ferritin dosage were evaluated. Student's t test, Univariate analysis, Chi-square and Odds Ratio were adopted (p<0.05). There was no significant difference regarding the serum ferritin levels between dentate and edentulous patients prior to surgery (p = 0.436). After surgery, the serum ferritin levels were higher in edentulous patients (prosthesis users) when compared to the pre-surgical levels, and the post-surgical levels presented significant difference regarding the dentate patients (p = 0.024). It can be concluded that rehabilitated patients in postoperative period showed better levels of serum ferritin after surgical intervention.

Effect of preoperative endoscopic decompression on malignant biliary obstruction and postoperative infection.

BACKGROUND/AIMS: The role of preoperative biliary drainage as an adjunct in patients undergoing surgical resection for malignant biliary obstruction is controversial. The objective of the present study was to evaluate the effects of preoperative endoscopic biliary drainage and its possible association with postoperative infection in patients presenting neoplastic obstructive jaundice. METHODOLOGY: The medical records of 53 patients presenting periampullary neoplasia were reviewed. In all of these patients, bile was obtained intraoperatively by puncture. Among the 53 patients, 14 had been submitted to preoperative endoscopic drainage (Group I) and 39 had undergone surgery without decompression (Group II). For statistical analysis, the level of significance was set at 5%. RESULTS: Bile culture was positive in 13 (92.8%) of the patients in Group I, a significantly higher incidence than that observed in group II, in which 16 (41%) of the patients presented positive cultures (p=0.001). There was no significant difference in general postoperative morbidity between groups (64.2% for group I vs. 46% for group II) or mortality (0% vs. 7.6%, respectively). When infective complications (cholangitis, pneumonia, wall infection) were analyzed separately, a higher incidence, although without significance, was found in Group I than in Group II (50% vs. 28.2%, respectively; p=0.1913). CONCLUSIONS: The presence of an endoscopic biliary drain provokes bacterial colonization, possibly due to the combination of residual cholestasis and duodenal reflux to the bile duct, raising concerns about the possible appearance of infective complications during the postoperative period.

[Is the mitochondrial respiratory activity a good parameter for hepatic ischemia and reperfusion injury?]. / A atividade respiratória mitocondrial é um bom parâmetro para a lesão por isquemia e reperfusão hepática?

BACKGROUND: Mitochondrial respiratory activity is associated with hepatic ischemia/reperfusion injury. AIM: To determine in vitro whether hepatic ischemia/reperfusion injury may be detected regardless mitochondrial respiratory activity. MATERIAL AND METHODS: Twenty-four heartworm-free mongrel dogs of either sex were randomized in the following groups: control, sham-operated dogs; I60, dogs subjected to 60 min of liver ischemia; I30/R60, dogs subjected to 30 min of ischemia e 60 min of reperfusion of liver; I45/R120 animals subjected to 45 min of ischemia and 120 min of reperfusion of liver. Blood and liver samples were taken after surgery to be processed. Mitochondrial respiratory activity was measured with a Clark-type oxygen electrode and mitochondrial membrane potential was calculated. lactic dehydrogenase, aspartate amino transferase and alanine aminotrasferase activities were determinated using laboratory kits, and malondialdehyde content in liver samples was estimated. RESULTS: The group I45/R120 showed increases of serum aminotransferase, lactic dehydrogenase and malondialdehyde in liver samples. Whereas no changes were registered in mitochondrial respiratory activities and mitochondrial membrane potential, a tendency of decrease in the rate of active respiration (state 3) could be observed. CONCLUSION: Under the conditions of this study, the results suggest the data from mitochondrial respiratory activity could show no significance difference among groups in hepatic ischemia/reperfusion injury. Hepatic ischemia reperfusion injury can be detected regardless mitochondrial respiratory activity.

Assessment of Oral Conditions and Quality of Life in Morbid Obese and Normal Weight Individuals: A Cross-Sectional Study.

The aim of this study was to identify the impact of oral disease on the quality of life of morbid obese and normal weight individuals. Cohort was composed of 100 morbid-obese and 50 normal-weight subjects. Dental caries, community periodontal index, gingival bleeding on probing (BOP), calculus, probing pocket depth, clinical attachment level, dental wear, stimulated salivary flow, and salivary pH were used to evaluate oral diseases. Socioeconomic and the oral impacts on daily performances (OIDP) questionnaires showed the quality of life in both groups. Unpaired Student, Fisher's Exact, Chi-Square, Mann-Whitney, and Multiple Regression tests were used (p<0.05). Obese showed lower socio-economic level than control group, but no differences were found considering OIDP. No significant differences were observed between groups considering the number of absent teeth, bruxism, difficult mastication, calculus, initial caries lesion, and caries. However, saliva flow was low, and the salivary pH was changed in the obese group. Enamel wear was lower and dentine wear was higher in obese. More BOP, insertion loss, and periodontal pocket, especially the deeper ones, were found in obese subjects. The regression model showed gender, smoking, salivary pH, socio-economic level, periodontal pocket, and periodontal insertion loss significantly associated to obesity. However, both OIDP and BOP did not show significant contribution to the model. The quality of life of morbid obese was more negatively influenced by oral disease and socio-economic factors than in normal weight subjects.

Effects on growth after portal hypertension induced in young rats.

BACKGROUND: Physical growth retardation in children with hypertension portal was observed regardless of schistosomiasis. It has been suggested that the shunt of portal blood through portosystemic collateral vessels would result in metabolic consequences that would lead to the physical growth deficit observed. AIM: Study the effects of hypertension portal in the growth of young rats. METHODS: The growth of 20 young rats, divided in the groups hypertension portal, n = 10, 103 +/- 3.7 g and sham operation n = 10, 102.6 +/- 3.4 g was evaluated throughout 5 weeks and the following parameters were under observation: quality of diet offered, diet ingestion, weight increase and urinary creatinine within 24 hours. At the end of the experiment, blood was taken for biochemical tests, prothrombin time and hematocrit and hypertension portal was measured. RESULTS/CONCLUSIONS: Rats with hypertension portal induced at early stages of their lives present growth delay in the first week after surgery recovering their growth rhythm in the next weeks, catching up with the sham animals. Differences related to urinary creatinine excretion, biochemical tests and hematocrit were not observed. Such results are evidence against the hypothesis that the hypertension portal induced in early stages of rats lives would cause delay in their growth.

Anemia and iron deficiency before and after bariatric surgery.

BACKGROUND: Iron deficiency and anemia are changes often associated with obesity. Bariatric surgery is responsible for increasing the iron loss and reducing its absorption. The objective of this study was to evaluate anemia and iron deficiency before and after bariatric surgery and to relate them to possible predisposing factors. METHODS: A retrospective study was conducted on obese patients submitted to open Roux-en-Y gastric bypass, in which clinical and laboratory data were obtained up to 48 months postoperatively. Patients were divided into groups according to the presence or absence of anemia and to the presence or absence of iron deficiency (even without anemia), and all data were compared between these groups. RESULTS: Preoperatively, 21.5% of patients had anemia and 20% had iron deficiency. The number of patients with anemia did not vary through the 4 years of the study, but ferritin levels significantly decreased with time (P<.01). Younger patients and patients with greater weight loss had a higher incidence of anemia. Female gender was a variable associated with a greater incidence of iron deficiency. CONCLUSIONS: Anemia and iron deficiency are frequent in obese patients and must be treated before surgery. Medical and nutritional surveillance is important in the postoperative period of bariatric surgery. Management of each condition must be directed at correcting the 2 major sources of iron deficiency and anemia: food intolerance (mostly meat intolerance) and losses (frequently due to menstruation). These are the factors more related to iron deficient anemia.

[Body perception and bariatric surgery: the ideal and the possible]. / Percepção corporal e cirurgia bariátrica: o ideal e o possível.

BACKGROUND: Bariatric surgery helps significantly in weight loss. Little is known whether the change in body shape and size is enough to meet the expectations created preoperatively. AIM: To evaluate the different perceptions of body size and shape before and after bariatric surgery. METHOD: A total of 423 patients were evaluated by Nine-figure Outline Scale. Of these, 32% were pre-surgery (PreS), 20% were evaluated between 10 and 12 months after surgery (PO-1), 13% between 18 and 24 months (PO-2), 15% between 30 and 36 months (PO-3) and 20% after 42 months of operation (PO-4). Groups were compared using one-way analysis of variance. RESULTS: When choosing figures that represented a man and a woman of normal size, no differences were observed between groups. Regarding the choice of figures representing the own size, differences were observed between groups PreS and all other groups (p<0.001), and PreS chosen larger figures. In choosing figures that represented a size that believed they could achieve, PreS differed from the PO-1, PO-2 and PO-3 (p <0.001), showing a tendency to choose larger silhouettes after surgery. When choosing figures that represented a size that would like to have PO-4 differed from PO-1 and PO-2 (p <0.05), showing that in the PO-4 there was a tendency to choose larger figures. CONCLUSION: The body perception seems to comply with own body size, even after weight loss. As longer postoperative period, the participants were more aware of the real possibilities of weight loss. There were signs of dissatisfaction with the body size and shape, mainly in the PO-1 and PO-2, which can lead to frustration and little use of the benefits of the surgery for health and quality of life.

Evaluation of oral health status and salivary flow rate in obese patients after bariatric surgery.

OBJECTIVES: The aim of this study was to identify the prevalence of dental caries, periodontal diseases and tooth wear in bariatric patients, and relate the oral health conditions to saliva flow. METHODS: Fifty-two patients who had undergone bariatric surgery (Roux-en-Y gastric bypass) and 50 severely obese patients indicated for bariatric surgery were submitted to clinical examinations with regard to dental caries (DMFT index), periodontal condition (CPI index), dental wear (DWI index - Dental wear index) and saliva flow. The data were statistically analyzed by the Student's-t, Mann-Whitney, Spearman Correlation and Chi-square (χ(2)) tests at 5% significance level. RESULTS: The DMFT index was 16.11±5.19 in the surgical group and 16.06±6.29 in the control group (P>.05). The mean CPI was 3.05±0.84 for the operated group and 2.66±1.25 for the obese patients with no significant difference between them (P>.05). There was statistically significant difference between the groups for the presence of periodontal pockets (P=.021). All the patients presented some degree of tooth wear, however, with no significant difference between the two groups (P=.82). The mean saliva flow values of the surgical group and control group were 0.64±0.46 mL/min and 0.66±0.49 mL/min, respectively. There was no significant difference in saliva flow and all oral conditions analyzed (P>.05). CONCLUSION: The prevalence of oral diseases was similar in severely obese patients who were candidates for bariatric surgery and in patients who had been submitted to bariatric surgery. Nevertheless, there was higher prevalence of periodontal pockets in the operated group.

Low educational status, smoking, and multidisciplinary team experience predict hospital length of stay after bariatric surgery.

OBJECTIVE: The objective of the present study was to identify new risk factors associated with longer hospitalization following bariatric surgery. METHODS: Patient clinical, social, and biochemical data in addition to multidisciplinary team experience were analyzed in a cohort that included all patients undergoing bariatric surgery at our hospital. The primary outcome was length of hospital stay (LOS). Mortality was recorded to validate the obesity surgery mortality risk score (OS-MRS). RESULTS: This study included 299 sequential patients, 41 ± 10 years of age, and BMI of 50 ± 8 kg/m(2) who underwent bariatric surgery. Two thirds (196) of patients were hypertensive, a third (86) were diabetic and a third (91) were current or former smokers. Overall, LOS was 8 ± 5 days. The predictors of a longer LOS were smoking (P < 0.05) and less multidisciplinary team experience (P < 0.05). Looking at only the last three years of data, LOS was 6 ± 5 days, and the predictors of a longer LOS were low educational attainment (P < 0.02) and smoking (P < 0.01) but not team experience. The global mortality was 2.6%, with the OS-MRS identifying a high-risk group. CONCLUSION: Excluding the initial learning phase, longer LOS independent predictors were patient low educational attainment and smoking. These predictors can help guide care to reduce complications.

Daily vitamin supplementation and hypovitaminosis after obesity surgery.

OBJECTIVE: The objective of this study was to determine whether constant daily vitamin supplementation would be sufficient to prevent possible vitamin deficiencies in obese patients undergoing bariatric surgery. METHODS: The study was conducted on 58 men and women (mean age 41 ± 10 y) who underwent Roux-en-Y gastric bypass RYGB and were assessed preoperatively and at 3, 6, and 12 mo after surgery. During the postoperative period, the patients received a multivitamin-mineral supplement on a daily basis. RESULTS: Serum ß-carotene and vitamin C were lower starting from the third postoperative month and continued to be low after 12 mo, and vitamin A was decreased by the sixth month and increased by 12 mo. Vitamin B12 levels were stable up to 6 mo but were decreased by 12 mo. Folic acid levels increased from the third month and remained higher throughout follow-up. One year after surgery there were 19% and 21% increases in the number of patients with vitamin A and vitamin C deficiency, respectively, and a 4% decreased of patients with folic acid deficiency. CONCLUSION: Weight loss and improvement in patients' general condition followed surgery, but serum levels of some vitamins were decreased despite the use of a vitamin-mineral supplement. These patients need continuous follow-up and individualized prescription of supplementation after the surgical procedure to prevent and treat vitamin deficiencies.

Prospective and randomized comparison of two techniques of staple line reinforcement during open Roux-en-Y gastric bypass: oversewing and bioabsorbable Seamguard®.

AIMS: Surgical staple line dehiscence usually leads to severe complications. Several techniques and materials have been used to reinforce this stapling and thus reduce the related complications. The objective was to compare safety of two types of anastomotic reinforcement in open gastric bypass. METHODS: A prospective, randomized study comparing an extraluminal suture, fibrin glue, and a nonpermanent buttressing material, Seamguard®, for staple line reinforcement. Fibrin glue was excluded from the study and analysis after two leaks, requiring surgical reintervention, antibiotic therapy, and prolonged patient hospitalization. RESULTS: Twenty patients were assigned to the suture and Seamguard reinforcement groups. The groups were similar in terms of preoperative characteristics. No staple line dehiscence occurred in the two groups, whereas two cases of dehiscence occurred in the fibrin glue group. No mortality occurred and surgical time was statistically similar for both techniques. Seamguard made the surgery more expensive. CONCLUSION: In our service, staple line reinforcement in open bariatric surgery with oversewing or Seamguard was considered to be safe. Seamguard application was considered to be easier than oversewing, but more expensive.

Histological, biochemical and pharmacological characterization of the gastric muscular layer in Chagas disease.

PURPOSE: To assess in vitro the correlation between the number of neurons and the sensitivity to cholinergic drugs and acetylcholinesterase activity in chagasic patients. METHODS: A 3 x 1 cm strip of the muscle layer of the anterior part of the stomach, always close to the angular incisure, was removed from 10 chronic chagasic patients (6 men) submitted to megaesophagus or megacolon surgery and from 10 non-chagasic patients (4 men) submitted to other types of surgery (control group), aged on average 52.3 and 50.1 years, respectively, for histological and pharmacological studies. The action of cholinergic drugs was investigated in isolated preparations according to the superfusion method of Ferreira and Costa, and acetylcholinesterase activity was determined by the method of Ellman. For neuron count, the strips were cut into 8 µm sections according to the method standardized by Alcântara. RESULTS: There was a difference in number of neurons between the chagasic (5,6) and control (7,3) groups. Acetylcholinesterase activity, in moles of hydrolyzed substrate per minute per gram tissue, was reduced in chagasic patients (4,32) compared to the controls (7,30). No hypersensitivity of the gastric musculature to cholinergic drugs was detected, with a reduced maximum response to carbachol and betanechol in the chagasic group. CONCLUSIONS: The reduction of neurons in the myenteric plexus of the stomach of chronic chagasic patients can be demonstrated even in the absence of clinical chagasic gastropathy. The hypersensitivity of the gastric musculature to cholinergic drugs probably depends on intense denervation. The reduced acetylcholinesterase activity demonstrates the involvement of the cholinergic innervation in the stomach of chronic chagasic patients. There was no correlation between number of neurons, sensitivity to cholinergic drugs and acetylcholinesterase activity in the gastric musculature of chagasic and non-chagasic patients.