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P Poitras

Publications and source records attributed to P Poitras.

66 records · Page 4Linked to original sources
PubMed1980

Motilin-independent ectopic fronts of the interdigestive myoelectric complex in dogs.

We have studied in four conscious dogs the relationship between circulating concentrations of motilin and the activity front (phase III) of the interdigestive myoelectric complex. During fasting, cyclic peaks of motilin secretion were concomitant in every instance with the initiation of activity fronts that began in the stomach or duodenum. When somatostatin was administered at doses of 5, 2.5, or 0.625 microgram x kg-1 x h-1 for 3 h, motilin concentrations were stabilized at lowered levels and no activity fronts occurred in the duodenum. Somatostatin also inhibited the stimulatory effects of exogenous motilin on the entire small intestine. During somatostatin infusion, however, ectopic fronts began in the jejunum and were propagated to the cecum despite low motilin concentration. After a 100-g meat meal, the cyclic increase of motilin was interrupted and no activity fronts were observed in the duodenum, but ectopic fronts started lower in the small intestine. Our study supports the hypothesis that motilin induces activity fronts in the canine duodenum, but it shows that ectopic fronts are not controlled by motilin.

Action Potentials↗
PubMed1979

Chronic non-specific ulcerative duodenojejunoileitis: report of four cases.

Four patients with chronic non-specific ulcerative duodenojejunoileitis (CNSUDJI) are reported. The clinical picture included abdominal pain, fever, and a malabsorption syndrome. Main rediological findings were diffuse narrowing of the jejunal loops with total effacement of the mucosal folds. Multiple peroral biopsies of the small intestine showed various degrees of mucosal abnormalities from total villous atrophy to normal villi, but ulcerations were diagnosed only by operative full thickness biopsies or resection of the small bowel. The ulcerative process was associated with well-documented coeliac disease in two patients: in one of them it occurred as a fatal complication involving also the colon, three years after the start of a gluten free diet, while the disease was in full clinical and histological remission. In the other case, coeliac disease was revealed by obstructive symptoms due to stenosing ulcerations; five months after surgical resection of the stenosis, institution of a gluten free diet induced a dramatic improvement. In the two other patients ulcerations were not associated with coeliac disease: one of them had a patchy villous atrophy and resisted a gluten free diet and total parenteral nutrition; she was improved by and dependent upon steroids but finally died. The last patient had normal villous height; ulcerations were located exclusively along the mesenteric border of the small bowel; he had a low-grade protracted evolution resisting any form of therapy and developed a peripheral neuropathy of unknown aetiology. On the basis of our cases and of a review of the literature the discussion focuses on the difficulty in diagnosing CNSUDJI, its relationship with coeliac disease, and its management and prognosis.

Adult↗
PubMedDate not supplied

Cholinergic regulation of motilin release from isolated canine intestinal cells.

An in vitro model was developed to study the regulation of motilin release from its endocrine-producing cell. Enzymatically dispersed cells from canine duodenojejunal mucosa were separated by centrifugal counterflow elutriation to enrich motilin content. From the motilin-enriched cell preparation, the release of motilin was determined under stimulation with various agents. Carbachol dose-dependently stimulated the release of motilin from its producing cell. Bombesin, morphine, and erythromycin, recognized stimulants for motilin release in vivo, failed to influence the secretion of motilin in vitro. Serotonin, GIP, CCK, pentagastrin, cisapride, neosynephrine, isoproterenol, or muscimol were also ineffective in the in vitro model. The response to carbachol was abolished by atropine but was not affected by somatostatin, serotonin, secretin, CCK, or GIP. These results suggest that muscarinic receptors are present on the motilin cell membrane and that acetylcholine is a major regulator of motilin release.

Acetylcholine↗
PubMedDate not supplied

Role of second messengers in the release of motilin from isolated canine intestinal cells.

We examined the intracellular mechanisms for the release of motilin in a preparation of mucosal cells obtained from dog duodenum. Enzymatically dispersed cells were separated by counterflow elutriation to enrich motilin content. Postreceptor activation process was studied by comparing the release of motilin obtained with exogenous analogues or stimulants of the various intracellular signal pathways. Dibutyryl cyclic adenosine monosphate (10(-3) M) and forskolin (10(-5) M) induced a moderate response in motilin secretion. Phorbol ester beta-phorphol-12-myristate-13-acetate and phospholipase C were potent stimulants of motilin release. Raising intracellular calcium concentration by calcium ionophore A23187 or increasing calcium content in the incubation milieu failed to modify the secretion of motilin. Analogues of 8-bromoguanosine-3'5' cyclic monosphosphate were ineffective. Therefore, the motilin cell was very sensitive to protein kinase C activators and appeared moderately responsive to a stimulation of the adenylate cyclase pathway.

Animals↗
PubMedDate not supplied

Motilin levels in term neonates who have passed meconium prior to birth.

Motilin levels were measured by radioimmunoassay from umbilical cord blood obtained at birth from 38 term neonates (median gestational age 40 weeks, range 39-42 weeks). Birth weights of these neonates ranged from 2,840 to 4,593 G (median 3,600 G). Forty-two percent (16/38) of these neonates passed antenatal meconium. The median motilin level was 177 fmol/ml in those neonates who passed antenatal meconium and 111.5 fmol/ml in those neonates who did not pass meconium prior to birth (p less than 0.01). Although fetal distress has been found to be associated with elevated motilin levels at birth, such an association was not found in this study. These data support an association between elevated motilin levels at birth and antenatal meconium passage.

Female↗
PubMedDate not supplied

Gastrointestinal symptoms and masticatory dysfunction.

One hundred and forty-two female patients consulting a prosthodontic clinic for masticatory disturbances and suffering from mandibular ridge atrophy were systematically interrogated for the presence of digestive symptoms. Eight-five subjects (60% of the studied population) reported current digestive complaints; 32 had abdominal pain (burning sensation, bloating or cramps), 12 presented stool transit alteration (constipation or diarrhoea) and 41 reported both abdominal pain and stool transit abnormalities. A prospective evaluation of the digestive symptoms was obtained following surgical reconstruction of the atrophic mandibular ridge and insertion of functional dental prostheses to correct masticatory dysfunction. One year after jaw surgery, 62 of 73 patients (85%) initially complaining of abdominal pain reported symptomatic improvement of their condition, while a marked amelioration in stool habits was noted in 34 of 53 patients (64%) initially suffering intestinal transit alteration. The high incidence of digestive complaints in our patients with dental deficits and the improvement of these symptoms after jaw reconstruction support a case for masticatory failure in the development of digestive symptoms.

Abdominal Pain↗