Toxoplasma gondii infection impairs the colonic motility of rats due to loss of myenteric neurons.

BACKGROUND: Toxoplasma gondii infection causes intestinal inflammation and diarrhea indicating possible intestinal motor dysfunction. Anatomical studies have shown alterations in the colonic myenteric plexus, but it is unknown whether this impacts motility and therefore whether motility is a target for treatment. We determined whether colonic coordinated movements are compromised by toxoplasmic infection and how it is associated with anatomical changes. METHODS: Male Wistar rats were evaluated at 6, 12, 24, 48, and 72 hours and 30 days postinfection (dpi) and controls. Infected rats received orally 5 × 103 sporulated oocysts of strain ME-49 (genotype II) of T gondii. The colon was collected for anatomical analysis (including the myenteric plexus immunolabeled with HuC/D, nNOS, and ChAT) and motility analysis in vitro (conventional manometry). Fecal output was measured daily. KEY RESULTS: At 12 hours postinfection, T gondii caused hypertrophy of the muscularis externa layer of the distal colon. There was loss of total, nitrergic, and cholinergic myenteric neurons in the proximal colon at 30 day postinfection (dpi); however, only loss of cholinergic neurons was found in the distal colon. Contractile complexes in the middle and distal colon were longer in duration in infected animals, which was associated with slower migration of the colonic motor complex. However, gastrointestinal transit time and fecal pellet output remained unchanged during the T gondii infection. CONCLUSIONS AND INFERENCES: Toxoplasma gondii caused myenteric neuronal loss in the proximal and distal colon and altered the motility pattern in the middle and distal colon to a more propulsive phenotype.

Progesterone, estrogen and pregnancy do not decrease colon myoelectric activity in rats: an in vivo study.

BACKGROUND: Progesterone, estrogen and the hormonal complex of pregnancy have been responsible for some degree of colon hypomotility in human pregnancy. OBJECTIVE: To find out if estrogen, progesterone and the hormonal complex of pregnancy decrease colon myoelectric activity. METHODS: The study was performed in 37 healthy female rats in which electrodes were implanted on the serosa of the proximal ascendent, distal ascendent, transverse, and descendent colon. We analyzed the records of colon myoelectric activity in vivo in five groups: control, ovariectomized, ovariectomized and treated with estrogen, ovariectomized and treated with progesterone, and pregnant rats. RESULTS: We found a great variation in myoelectric activity in all groups studied. The mean of electric activity did not show statistical difference among the five groups, but pregnant rats had a statistically significant higher duration of maximum electric activity in all distances from the cecocolon junction. CONCLUSION: Pregnant rats had a statistically higher duration of maximum electric activity. If we could transpose these results to humans, this increase in duration of colon myoelectric activity could explain, in part, the slight constipation that some pregnant women have.

Patterns of small intestinal motor activity during intraluminal infusion of elementary diets in dogs.

During continuous intraintestinal infusion of elementary diets, periodic fluctuation of the frequency of contractions has been observed. This study sought to characterize the temporospatial organization of this pattern and the influence of cholinergic input. Studies were performed on unanesthetized dogs with a duodenal cannula. Motor activity was recorded by means of infused catheters and external transducers. Nutrients were infused continuously at the duodenum and jejunal levels. Studies were repeated after administration of atropine. Six to 14 periodic variations of frequency of contractions during 10 basal infusion experiments were observed in random order. During duodenal infusion, atropine significantly increased the number of these events, associated with a synchronous pattern. Frequency and amplitude of contractions during jejunal infusion were significantly lower compared to duodenal infusion. Cyclic pattern elicited by nutrient infusion is related to a cholinergic mechanism; changes depend on the level of infusion.

Electrogastrography in patients with Chagas' disease.

Electrogastrograghy (EGG) was performed in 33 patients with Chagas' disease and in 15 healthy volunteers-control group. The EGG was performed in two different periods: in fasting and postprandial. The EGG was submitted to a continuous spectral analysis. The following parameters were evaluated: % dominant frequency in spectral bands: normogastria (2-4 cpm), bradygastria (1-2 cpm), tachygastria (4-10 cpm) and duod/resp (10-15 cpm). EGG was considered normal if normogastria > 65% in both EGG periods. The chagasic group showed % normogastria significantly lower (basal, P < 0.01), % bradygastria (basal, P = 0.01) and % tachygastria (basal and postprandial, P =.001) significantly higher than the control group. EGG was normal in 14/15 (93%) in control group x 16/33 (53%) in chagasic group (P < 0.05). It was concluded that: 1) the prevalence of gastric dysrhythmias was higher in chagasic patients than in comparison to a control group 2) gastric dysrhythmias may be considered one of the abnormalities presented in the chagasic gastropathy.

Postprandial symptoms in dysmotility-like functional dyspepsia are not related to disturbances of gastric myoelectrical activity.

Gastric dysrhythmias, such as tachy- or bradygastria, have been reported in patients with functional dyspepsia (FD), but their role in symptom production is uncertain. It is also not known whether gastric dysrhythmias in these patients can be elicited by physiological gastric distension with a meal. We investigated the relationships between symptoms after ingestion of different volumes of water following a test meal and gastric dysrhythmias in FD patients. Fourteen patients with dysmotility-like FD and 13 healthy volunteers underwent paired electrogastrography (EGG) studies. Fasted subjects ingested 150 ml of yoghurt with either 150 ml (low volume) or 300 ml (high volume) water in random order. Fasting and fed EGGs with monitoring of symptoms were performed in both studies. Ten FD patients (71.4%) reported upper abdominal discomfort and bloating after the low volume meal, but only one (7.1%) presented an abnormal EGG (dominant frequency in the 2-4-cpm range: 58%). Following the high volume meal, 7 patients (50%) had symptoms, but none had EGG abnormalities. No significant differences were found between FD patients and controls for any of the EGG variables, in any test. In FD patients with postprandial symptoms, the percentage of the EGG dominant frequency in the normal range (median, 84.6%; range, 76.0-100.0%) was similar (P>0.20) to that in those without symptoms (88.5%; 75.0-100.0%). We conclude that disturbances of gastric myoelectrical activity are unlikely to play a role in the origin of postprandial upper abdominal discomfort and bloating in dysmotility-like FD.

Canine small bowel motor activity in response to intraduodenal infusion of nutrient mixtures of increasing caloric load in dogs.

The effect of nutrients on small intestinal motility is controversial. Our aim was to analyze the effect of intraduodenal infusion of mixtures of nutrients of increasing caloric load, on intestinal motility. Studies were performed in dogs with a duodenal cannula. Isosmolar infusions of saline, 0.5, 2, and 4 kcal/min were performed and motility recorded by means of infused catheters. Nonstatistically significant differences were observed between frequency of contractions during infusion of 0.5 (4.1 +/- 1.6 cpm) and 2 kcal/min (5.3 +/- 1.5 cpm) compared to control (4.3 +/- 1.9 cpm). With 4 kcal/min a significant decrease of frequency (2.7 +/- 0.9 cpm) was observed. A similar finding was observed for amplitude of contrations. With 0.5 kcal/min fasting cyclic activity was still present, but the numbers of phase III were significantly reduced, associated with an increased duration of phase II. With higher caloric loads cyclic fasting activity was replaced by marked variations of frequency, following a cyclic pattern. A lower threshold for mechanisms switching the fasting to fed state was observed, compared to those controlling frequency and amplitude.

Gastric myoelectrical activity in neonates of different gestational ages by means of electrogastrography.

PURPOSE: to describe the patterns of the gastric myoelectrical activity, pre-and postprandially, in clinically stable neonates of different gestational ages, during their first two weeks of life by means of Electrogastrography. PATIENTS AND METHODS: Electrogastrography was recorded in forty-five clinically stable neonates of different gestational ages (group I: 15 neonates of > 37 weeks, group II: 15 premature neonates of 32-37 weeks; Group III: 15 premature neonates of 28-31 weeks) receiving intermittent enteral feedings during their first two weeks of life. Electrogastrography recordings were performed for 1 hour pre-and postprandially. The Electrogastrography signal was recorded using the portable MicroDigitrapper Electrogastrography recording device and after motion artifacts were deleted, the remaining Electrogastrography data were submitted to quantitative analysis based on the "Running Spectrum Analysis". RESULTS: The percentages of normogastria, pre-and postprandially were greater than the percentages of gastric dysrythmias in all three studied groups. Furthermore, all neonates had the mean values of the Electrogastrography dominant frequency predominantly within the normogastria range, in both periods analyzed. There were no significant differences in the relative change of the Electrogastrography dominant power among the groups. CONCLUSION: This study demonstrates that the Electrogastrography patterns are similar between premature and full term neonates during the pre-and postprandial periods. The results of this study also indicate that the gastric myoelectrical activity in premature and full term neonates is immature, as compared to that described for older neonates, children and adults.

Gastric myoelectrical activity in neonates of different gestational ages by means of electrogastrography

PURPOSE: to describe the patterns of the gastric myoelectrical activity, pre-and postprandially, in clinically stable neonates of different gestational ages, during their first two weeks of life by means of Electrogastrography. PATIENTS AND METHODS: Electrogastrography was recorded in forty-five clinically stable neonates of different gestational ages (group I: 15 neonates of > 37 weeks, group II: 15 premature neonates of 32-37 weeks; Group III: 15 premature neonates of 28-31 weeks) receiving intermittent enteral feedings during their first two weeks of life. Electrogastrography recordings were performed for 1 hour pre-and postprandially. The Electrogastrography signal was recorded using the portable MicroDigitrapper Electrogastrography recording device and after motion artifacts were deleted, the remaining Electrogastrography data were submitted to quantitative analysis based on the "Running Spectrum Analysis". RESULTS: The percentages of normogastria, pre-and postprandially were greater than the percentages of gastric dysrythmias in all three studied groups. Furthermore, all neonates had the mean values of the Electrogastrography dominant frequency predominantly within the normogastria range, in both periods analyzed. There were no significant differences in the relative change of the Electrogastrography dominant power among the groups. CONCLUSION: This study demonstrates that the Electrogastrography patterns are similar between premature and full term neonates during the pre-and postprandial periods. The results of this study also indicate that the gastric myoelectrical activity in premature and full term neonates is immature, as compared to that described for older neonates, children and adults

Alterations of intestinal motor responses to various stimuli after Nippostrongylus brasiliensis infection in rats: role of mast cells.

Nippostrongylus brasiliensis infection induces jejunal mastocytosis associated with enteric nerve remodelling in rats. The aim of this study was to evaluate the intestinal motility responses to meals and to neurotransmitters involved in the control of gut motility (acetylcholine (carbachol), substance P and neurokinin A) in both control and N. brasiliensis-infected rats 30 days post-infection. All rats were equipped with NiCr electrodes in the jejunum to record myoelectrical activity. The duration of disruption of the jejunal migrating myoelectrical complexes (MMC) induced by the different stimuli was determined. Meal ingestion and substance P administration disrupted the MMC pattern for similar durations in the two groups. Carbachol and neurokinin A induced a significantly longer MMC disruption in post-infected rats than in controls (125 +/- 8.3 vs. 70 +/- 6 min for carbachol 100 microg kg-1 and 51 +/- 4 vs. 40 +/- 2 for neurokinin A 50 microg kg-1). The enhanced motor response in postinfected rats was reduced by previous mast cell stabilization with ketotifen or mast cell degranulation with compound BrX 537 A. In conclusion, the increased intestinal motor reactivity to carbachol and neurokinin A in post-N. brasiliensis-infected rats depends upon intestinal mast cell hyperplasia and degranulation.

Effects of small bowel exclusion on intestinal myoelectrical activity pattern: comparison between innervated and denervated (transplanted) Thiry-Vella loops in rats.

Small bowel transplantation (SBT) leads to several changes in normal intestinal physiology with special reference to lymphatic disruption and graft denervation. Intestinal myoelectrical activity (MA) has been studied in different conditions, but little is known about MA in excluded bowel segments without the influence of nutrients. We performed this study to evaluate the effects of bowel exclusion on MA pattern. Fifteen Wistar rats were divided into two groups: five were used as donors and five as recipients for SBT; the remaining five underwent isolation of a jejunal segment as Thiry-Vella loop (TVL). On the 20th postoperative day, four bipolar electrodes were implanted in the small bowel of each rat: proximally and distally on the transplanted and the native intestine (SBT group); proximally and distally on the TVL and across the jejunal anastomosis (TVL group). On the 30th postoperative day, MA was recorded for 30 min after a 12 h fast. MA pattern was not altered by the exclusion of innervated jejunal segments (TVLs) with maintenance of high amplitude and migrating myoelectric complex (MMC) occurrence independent of MA in the continuity bowel. The characteristic regular spiking activity was not observed in transplanted grafts and MA analysis showed slow waves containing superimposed irregular spiking activity.

Estudo do padräo mioelétrico do cólon esquerdo em pacientes portadores de esquistossomose mansônica na forma hepatoesplênica

O granuloma esquistossomótico determina lesSes anatomopatológicas a nível dos plexos mioentéricos e submucoso do trato gastrointestinal, secundárias a reaçSes imunológicas. Essas lesSes podem produzir alteraçSes da motilidade intestinal. O objetivo deste estudo foi determinar o padrÝo da atividade mioelétrica do cólon esquerdo em pacientes esquistossomóticos, na forma hepato-esplênica. Foram utilizados dezessete pacientes, sendo doze esquistossomóticos e cinco do grupo controle, submetidos a histerectomia. Eletrodos bipolares cobertos por Téflon (fio de marcapasso) foram implantados a nível da tênia anterior do cólon esquerdo, em número de três pares, distando cinco centímetros (cm) um do outro, estando o último eletrodo a vinte cm da reflexÝo peritoneal. Após a recuperaçÝo do íleo paralítico pós-operatório, iniciou-se o processo da coleta de dados . Foi utilizado um sistema de aquisiçÝo de dados (DATA Q Série 200), que capta frequencia entre 0,02 a 10 Hz. Antes de serem registrados na placa de aquisiçÝo de dados, os sinais foram amplificados com um ganho de 1000 vezes, e armazenados em disquetes, utilizando-se um software de aquisiçÝo (WINDAQ 200), que roda no ambiente WINDOWS. As frequências situadas abaixo de 0,3 Hz sÝo selecionadas para a Atividade Elétrica de Controle (AEC) e as frequências entre 0,7 e 10Hz selecionadas para a Atividade Elétrica de resposta (AER). Os resultados obtidos evidenciaram uma AEC com predomínio da baixa frequencia nos dois grupos de pacientes esquistossomóticos apresentou uma AEC estatisticamente menor, quando comparado com o grupo controle (p=0,009). A AER de curta duraçÝo também apresentou uma diferença estatísticamente significativa (p=0,037). Ou seja, o grupo de pacientes esquistossomóticos apresentaram uma média de 96,56 contraçSes por hora, enquanto que os pacientes do grupo controle apresentaram em média 128,83 contraçSes por hora. NÝo houve diferenças relacionadas à duraçÝo da AER de curta duraçÝo. A AER de longa duraçÝo nÝo apresentou diferença estatisticamente significativa, tanto em relaçÝo ao número, quanto à duraçÝo, assim como nÝo houve diferenças relacionadas ao "cluster". O autor conclui que os pacientes portadores de esquistossomose hepatoesplênica apresentam uma AEC e uma AER de curta duraçÝo menores do que o grupo controle, nÝo havendo diferenças no que tange à AER de longa duraçÝo e o número e duraçÝo dos "cluster"

Abnormalities of the interdigestive migrating motor complex in a patient with carcinoid syndrome.

Intraluminal pressures of the gastric antrum, duodenum and jejunum were recorded for 206 min after a 12 h fast in a patient with carcinoid syndrome due to neoplasia of enterochromaffin cells of the ileum and with hepatic metastases. The most conspicuous alteration was a tachyrrhythmia of 16 waves/min predominating in the activity fronts of both duodenum and jejunum. Periods of 11-12 waves/min frequency appeared irregularly and the simultaneous occurrence of frequencies of 11 waves/min and 16 waves/min was also recorded. The gastric antrum was fully quiescent throughout the study. The alterations observed are presumed to be produced by substances secreted by the carcinoid tumor.

[Effect of casein on the temporo-spatial organization++ of the contractile activity of the small intestine in the dog]. / Efecto de la caseína en la organización temporo-espacial de la actividad contráctil en el intestino delgado del perro.

Some observations in man and experimental animals have demonstrated that casein decreases intestinal transit speed. However, its effects on intestinal motility have not been studied previously in a systematic fashion. The aim of this work was to study the temporospatial distribution of small bowel motility before and after the administration of calcium caseinate. Studies were performed in fasting dogs using 6 catheters perfused with a pneumo-hydraulic system. After the administration of 300 ml of a 10% solution of calcium caseinate, a global decrease in motor activity was observed, specially of grouped propulsive contractions, they were reduced in 64.9 to 19.5%. On the contrary, a significative increase, in 1.4 to 22%, of individual wave, non propulsive motor activity was observed. These quantitative changes in contractions, specially in their organization and temporo-spatial distribution, may be responsible for the decrease in intestinal transit after the administration of casein.

Effect of early feeding on maturation of the preterm infant's small intestine.

To determine the response of the preterm infant's intestine to entire feedings at different postnatal ages, we recorded results of manometry of the gastroduodenum and determined fasting plasma concentrations of gastrin, gastric inhibitory peptide, neurotensin, and peptide YY three times in each of two groups: 27 preterm infants were randomly assigned to receive hypocaloric enteral nutrition on postnatal days 3 to 5 (early feeding) or on days 10 to 14 (late feeding). Initial observations (study 1) were performed by the fifth postnatal day; study 2 was performed on days 10 to 14, and study 3 on days 24 to 28. Early-fed infants received hypocaloric feedings immediately after study 1; late-fed infants did not receive enteral feedings until the completion of study 2. Although motor activity and fasting gastrointestinal peptide concentrations did not differ between groups at study 1, at study 2 early-fed infants had significantly more mature motor patterns than did babies not being fed. Early-fed infants also had significantly higher plasma concentrations of gastrin and gastric inhibitory peptide than did late-fed infants; neurotensin and peptide YY values were similar in both groups. By the time of study 3, when late-fed infants had also received enteral feedings, gut development was not different in the two groups. However, early-fed infants were able to tolerate full oral nutrition sooner, had fewer days of feeding intolerance, and had shorter hospital stays. Thus the provision of early hypocaloric nutrition was associated with earlier nutrition of preterm infants' intestinal function and resulted in improved feeding tolerance. These findings support the use of early feedings in preterm infants.