Lower oesophageal sphincter response to pentagastrin in chagasic patients with megaoesophagus and megacolon.

Intraluminal manometric studies were performed in 14 chagasic patients with megaoesophagus, 10 chagasic patients with megacolon, and 15 control subjects. Basal lower oesophageal sphincter pressure was 20.27+/-1.16 mmHg (mean+/-SEM) in controls as compared wtih 15.16+/-1.53 mmHg in chagasics with megaoesophagus and 14.38+/-1.50 mmHg in chagasics with megacolon. Dose-response studies to intravenous pentagastrin showed that the chagasic patients exhibited a lower sensitivity to the stimulant than did the controls, as demonstrated by shifting of the dose-response curve to the right and higher individual values of the dose for half maximal contraction (D50). No difference was noted between the calculated maximal contraction (Vmax) of oesophageal sphincter of controls and chagasics. These data are compatible with the hypothesis of an interaction between pentagastrin and cholinergic nervous excitation on oesophageal sphincteric smooth muscle.     

Gallbladder motor function in chagasic patients with megacolon and/or megaesophagus

Gallbladder motor function was evaluated in 21 Chagasic patients with megacolon and/or megaesophagus and the results were compared with those obtained in 19 control subjects. Gallbladder contraction was evaluated by the radiologic method after the application of two different stimuli: an exogenous one consisting of intravenous injection of cholecystokinin octapeptide at the dose of 30 ng/kg over a period of 1 min, radiologic evaluation was performed before and 5, 10, 15 and 20 min after the stimulus; an endogenous one produced by standardised intraduodenal instillation of a lipid emulsion, radiologic evaluation was performed before and 3, 5, 10, 15, 20, 25 and 30 min after the beginning of intraduodenal infusion. The gallbladder of the Chagasic patients was found to be hypersensitive to both stimuli, since it contracted in a statistically more intense manner, with contraction starting earlier and lasting longer than among the controls. This difference in contracting behavior suggests impairment of the inhibitory intrinsic innervation of the gallbladder.     

Incidence of diverticular disease of the large bowel in non-chagasic and chagasic individuals with and without megacolon

To study the frequency of association between two common colonic disease in our midst, chagasic megacolon and diverticular disease, we reviewed the barium enemas of 243 patients aged more than 35 years. Diverticula were detected in 22 (21.6%) of the 102 non-chagasic individuals, in 10 (35.7%) of 20 chagasics without megacolon, and in 14 (12.4%) of the 113 chagasics with megacolon. There was a statistically significant difference between the two chagasic groups, but not between each one of them and the non-chagasic group. The incidence of diverticula in the sigmoid colon of the non-chagasic group was significantly higher than in the sigmoid colon of the other two groups studied. Among the patients with association of megacolon and diverticular disease, the diverticula were always located in the nondilated portions of the large bowel. It is suggested that totally unfavorable conditions for the genesis and/or maintenance of diverticula exist in the dilated colon of chagasic patients.     

Prevalence of rectoanal inhibitory reflex in chagasic megacolon

BACKGROUND: Rectoanal inhibitory reflex is not always evident in patients with chagasic megacolon. This may be due to insufficient volumes of air used during insufflation for the manometric examination. AIMS: To identify the volume of air necessary to induce rectoanal inhibitory reflex in patients with chagasic megacolon and to observe its prevalence in these individuals. METHODS: Rectoanal inhibitory reflex in 39 patient with chagasic megacolon was studied by means of anorectal manometry using the balloon method. The balloon was insufflated using sequential volumes up to 300 mL to induce reflex. RESULTS: Rectoanal inhibitory reflex was identified in 43.6% of the patients using a mean volume of 196 mL of insufflated air (standard error = 13.5). CONCLUSION: Rectoanal inhibitory reflex can be induced in patients with chagasic megacolon when greater volumes of air are used.     

Relation between mast cells concentration and serotonin expression in chagasic megacolon development

Chagas’ disease is still reaching about 10 million people in the world. In South America, one of the most severe forms of this disease is the megacolon, characterized by severe constipation, dilated sigmoid colon and rectum and severe malnutrition. Previous data suggested that mast cells and serotonin (5‐hydroxytryptamine [5‐HT]) expression could be involved in intestinal homeostasis control, avoiding the chagasic megacolon development. The aim at this study was to characterize the presence of mast cells and expression of serotonin in chagasic patients with and without megacolon and evaluate the relation between mast cells, serotonin and megacolon development. Our results demonstrated that patients without megacolon feature a large amount of serotonin and few mast cells, while patients with megacolon feature low serotonin expression and a lot of mast cells. We believe that serotonin may be involved in the inflammatory process control, triggered by mast cells, and the presence of this substance in large quantities of the intestine could represent a mechanism of megacolon prevention.     

Preponderance of inhibitory versus excitatory intramuscular nerve fibres in human chagasic megacolon

Introduction

Megacolon, chronic dilation of a colonic segment, is a frequent sign of Chagas disease. It is accompanied by an extensive neuron loss which, as shown recently, results in a partial, selective survival of nitrergic myenteric neurons. Here, we focused on the balance of intramuscular excitatory (choline acetyltransferase [ChAT]-immunoreactive) and inhibitory (neuronal nitric oxide synthase [NOS]- as well as vasoactive intestinal peptide [VIP]-immunoreactive) nerve fibres.

Materials and methods

From surgically removed megacolonic segments of seven patients, three sets of cryosections (from non-dilated oral, megacolonic and non-dilated anal parts) were immunhistochemically triple-stained for ChAT, NOS and VIP. Separate area measurements of nerve profiles within the circular and longitudinal muscle layers, respectively, were compared with those of seven non-chagasic control patients. Additionally, wholemounts from the same regions were stained for NOS, VIP and neurofilaments (NF).

Results

The intramuscular nerve fibre density was significantly reduced in all three chagasic segments. The proportions of inhibitory (NOS only, VIP only, or NOS/VIP-coimmunoreactive) intramuscular nerves were 68?%/58?% (circular/longitudinal muscle, respectively) in the controls and increased to 75?%/69?% (oral parts), 84?%/76?% (megacolonic) and 87?%/94?% (anal) in chagasic specimens. In the myenteric plexus, NF-positive neurons co-staining for NOS and VIP also increased proportionally. The almost complete lack of dendritic structures in ganglia of chagasic specimens hampered morphological identification.

Discussion and conclusion

We suggest that preponderance of inhibitory, intramuscular nerve fibres may be one factor explaining the chronic dilation. Since the nerve fibre imbalance is most pronounced in the anal, non-dilated segment, other components of the motor apparatus (musculature, interstitial cells, submucosal neurons) have to be considered.     

Rectosigmoidectomy with ileal loop interposition: a new surgical method for the treatment of chagasic megacolon

PURPOSE: Chagasic megacolon occurs frequently in central Brazil. There are several surgical techniques for the treatment of megacolon and no consensus on which one is the best. Our goal is to present a new surgical treatment for chagasic megacolon. METHODS: One hundred forty-seven patients with chagasic megacolon were submitted to surgical treatment between January 1985 and December 1995. Fourteen patients were lost to follow-up because they could not be reached. Patients were evaluated preoperatively and submitted to rectosigmoidectomy with interposition of an isoperistaltic segment of ileum between the descending colon and the rectum. RESULTS: There were three deaths in the postoperative period, two because of complications caused by septic peritonitis and one because of hypovolemic shock. Major complications occurred in 5.4 percent of the cases: four dehiscences at the ileocolic anastomosis and two at the ileorectal anastomosis. Minor complications corresponding to 3.1 percent of the total included two with abdominal wall infection, one with a temporary infection, and one with a cardiac arrhythmia. Four patients (3.1 percent) had recurrence of constipation. CONCLUSION: Rectosigmoidectomy with interposition of an ileal segment is a new therapeutic option for chagasic megacolon that has several advantages in relation to the other techniques because of its ease of execution, lack of complications such as those seen in pull-through procedures, and a low recurrence rate.     

Esophageal cancer in patient with chagasic megaesophagus

BACKGROUND: Megaesophagus constitutes a public health problem in our country since it affects individuals in the most productive phase of their lives. During the development of the disease, people suffering from it may present association with esophageal cancer. AIM: To analyze the clinical and epidemiological aspects of patients with megaesophagus and esophageal cancer. METHODS: Twenty patients with megaesophagus and cancer (group 1) and 20 patients with esophageal cancer (group 2) were retrospectively analyzed. Demographic data, habits (alcoholism and smoking), tumor histological type, lesion location, cellular differentiation, staging, treatment and survival were assessed. RESULTS: No difference was observed between the groups in relation to age, sex, lesion location, tumor histological type, cellular differentiation, staging or survival. As regards habits, the association of alcoholism with smoking was observed in a larger number of patients with esophageal cancer without the megaesophagus antecedent. CONCLUSION: The clinical characteristics of patients with megaesophagus and cancer do not differ from those of patients with malignant esophageal neoplasia, particularly as regards the unfavorable prognosis with the instituted treatment. Patients with megaesophagus may present esophageal tumor at any part of the organ.     

Valsalva maneuver in chagasic patients with documented past medical history of acute chagasic myocarditis

BACKGROUND: We studied the heart rate responses to the Valsalva maneuver in eight patients with documented past medical history of acute Chagas' disease. METHODS: Four patients were studied 8-21 months after the acute episode and four, 58-68 months thereafter (age 25+/-8.65 years M+/-S.D.). Seventeen healthy subjects of similar age were included as controls (age 27+/-7.5 years, P=NS). RESULTS: Baseline heart rate was higher in chagasic patients (88+/-15 beats/min) compared to controls (69.8+/-9.8, P=0.001). Maximum heart rate at phase II of the maneuver was also higher (114+/-16.3 vs. 101.5+/-9.9, P=0.02). Minimum heart rate at phase IV was, however, not different (57.4+/-10.4 vs. 63.3+/-7.3 P=NS). The magnitude of the absolute negative change at phase IV was larger in the chagasic patients, although, not different (-50.8+/-13.8 vs. -44+/-13.8, P=NS). The Valsalva index was 1.81+/-0.26 in the chagasic patients and 1.82+/-0.42 in the controls (P=NS). Minimum heart rate at phase IV correlated neither with the baseline heart rate (r=-0.28, P=NS) nor with the Valsalva index (r=-0.40, P=NS). The magnitude of the absolute negative change during phase IV correlated with, both, the baseline heart rate (r=-0.80, P<0.01) and the Valsalva index (r=-0.95, P<0.0001). The higher baseline high rate influenced the magnitude of the negative heart rate change, but not the minimum heart rate reached at phase IV. CONCLUSIONS: Chagasic patients with proven past medical history of acute Chagas' disease had unimpaired heart responses to the Valsalva maneuver.