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Biomedical subjects

Y Ruckebusch

Publications and source records attributed to Y Ruckebusch.

At least 109 records · Page 6Linked to original sources
PubMed1981

Gastric pH changes associated with duodenal motility in fasted dogs.

1. The electrical activity of the antrum and duodenum was recorded from chronically implanted electrodes in six conscious dogs fitted with gastric and/or duodenal cannulae. Antral and duodenal pH were concomitantly registered using glass electrodes inserted through the respective cannula. 2. In dogs fasted for 18-24 h an alkalinization of the antrum of about 5 pH units lasting 15-30 min occurred regularly at 90-120 min intervals at the cessation of a period of antral spiking activity. This antral alkaline period was accompanied by the reflex of intestinal juice into the stomach, as determined by the presence of bile salts in gastric samples. 3. The antral pH rise was related to the development of a phase of regular spiking activity (RSA), or activity front, on the proximal duodenum concomitant with the motor quiescence of the antrum. The rise in pH disappeared after occlusion of the pylorus, which prevented the passage of duodenal contents into the antrum. 4. It is concluded that the mean antral pH value is 5.8 for half the recording time in fasted dogs, the causative factor of this alkalinization being the regurgitation of duodenal contents into the antrum while quiescent. Accordingly, more alkaline duodenal contents were observed during the occurrence of the RSA phase and the following gastro-duodenal quiescence; then the progressive acidification of the gastric and duodenal contents when the motility reappeared may be an inducing factor of a new RSA phase.

Action Potentials↗
PubMed1981

[Not Available].

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Animal Population Groups↗
PubMed1981

Effect of dietary fiber on gastrointestinal motility and jejunal transit time in dogs.

Strain gauge recordings of the motility of the antrum, duodenum, and jejunum were made in 10 dogs receiving a daily meal of canned food. Addition of 30 g of either wheat bran, cellulose, or guar gum increased the duration of the postprandial pattern of motility by 41-54% in the duodenum. Only cellulose and gum caused increases in the duration of the postprandial pattern of motility in the jejunum. The normal postprandial pattern of duodenojejunal contractions consisted of bursts of 4-10 rhythmic contractions. When bran or cellulose were added, the bursts were prolonged (12-15 contractions per burst) with 4-15 min intervals between bursts. In contrast, when gum was added, contractions occurred continuously at a rate of 7-8/min, but their amplitude was one-half that seen with the other fibers. The increased number of low amplitude contractions when gum was added caused the postprandial motility index to double. There was no change in the motility index when cellulose was added. Guar gum also increased the frequency of antral contractions by 129%, while bran and cellulose had no effect. Jejunal transit time and flow of digesta were measured in four dogs 2 h after the meal. Addition of bran or gum increased the transit time by 28% and 51%, respectively, but cellulose caused a 900% increase in transit time associated with a 50% reduction in the flow of digesta. Addition of different fibers causes different alterations in postprandial motility. Jejunal transit of digesta appears unrelated to the pattern of contractions.

Animals↗
PubMed1980

Motor profile of the ruminant colon: hard vs soft faeces production.

The spiral colon, despite its similarity in ovine and bovine species is only the site of pellet formation in sheep. This peculiarity is associated with a permanent and localized contractile activity of the ovine spiral colon instead of 5-min periods of continuous activity migrating slowly aborally in cattle.

Animals↗
PubMed1980

Colonic myoelectrical activity and propulsion in the dog.

Electrical spike activity was recorded on the colon of the dog. The duration of the bursts of the spike was used to divide the spike activity into two different types: long and short spike bursts (LSB and SSB). LSBs lasted from 7 (ascending) to 37 sec (descending) and SSBs lasted about 1 sec, independent of the site. These measurements were applied to colons of colostomized dogs for which the colonic transit time was negatively correlated to the LSBs expressed as percent of the time. The effects of high- and low-residue diets were tested. Intake of large amounts of dry food was associated with an increase of the LSB activity. A meat diet was accompanied with an increase of the SSB activity. These results suggest a propulsive effect for the LSBs stimulated by large amounts of colonic contents while the SSB activity may reflect some degree of emptiness.

Animals↗
PubMed1980

Origin of high slow-wave frequency in the dog colon.

Using intraparietal and intraluminal electrodes, duodenal and colonic electrical activities were simultaneously recorded in dogs under pentobarbital anaesthesia to study the temporal relationship between the slow-wave frequency of the colon and that of the proximal duodenum. The colonic electromyogram showed two distinct slow-wave frequencies, one in the range of 7-9 cycles/min, and the other in the range of 18-19 cycles/min. The latter was synchronized to that observed on the duodenum, and disappeared after removal of the entire duodenum and the proximal jejunum over 90 cm, from 8 to 98 cm from the pylorus. After transversally cutting the muscular layers of the duodenum at 8 cm from the pylorus, the high slow-wave frequency of the colon decreased to 16-16.5 cycles/min, similarly to that observed on the duodenum aborally to the section. When another section was performed 5 cm aborally to the first cutting level, the colonic slow-wave frequency was again synchronized to that of the duodenum observed aborally to the second section. Intraduodenal infusion of cold water decreased the amplitude of both the duodenal and the colonic slow-waves by 50 p. 100 and the frequency by 30 p. 100. Since all these experimental procedures did not affect the colonic slow-wave frequency at 7-9 cycles/min, and no temporal relationship was found between duodenal and colonic spiking activities, it was concluded that (i) the colonic slow-wave frequency at 18-19 cycles/min, recorded from both the intraparietal and the intraluminal electrodes in dog, was an "artefact" of duodenal activity acting as an electric dipole and (ii) that the only slow-wave frequency of 7-9 cycles/min was generated by the colon.

Action Potentials↗
PubMed1980

Effect of anthraquinone derivatives on canine and rat intestinal motility.

The effects on gastrointestinal motility of 3 senna preparations containing 18% oxidized Ca-sennosides, 60% Ca-sennosides, or pure sennosides A + B were tested in dogs and rats as measured by electromyography. Oral administration of the oxidized products in the fasted animal increased the activity of the small intestine within 2 h and reduced both caecal and colonic contractions for 24 h. Severe diarrhoea was present 4-6 h after administration and lasted for at least 1 day. Ca-sennosides had a similar, but weaker effect while pure sennosides affected motility only 6-10 h after oral administration. The intracolonic administration of the oxidized products resulted in an immediate reduction of colon motility for 7-8 h and diarrhoea was present within 40 min. Intracolonic Ca-sennosides and sennosides A + B induced only small changes in the intestinal motility, but diarrhoea also appeared. The results confirm that pure sennosides act predominantly on large intestine motility after their degradation by colonic microorganisms. Oxidized products are already effective in the upper gastrointestinal tract. The early action of Ca-sennosides requires further investigation. Side effects after oral senna treatment such as griping or nausea may be caused by motility changes induced by the presence of small amounts of oxidized products in the drug.

Animals↗
PubMed1980

Evaluation of colonic myoelectrical activity in health and functional disorders.

Electrical activity of the colon was investigated in six healthy volunteers and 22 patients presenting functional colonic disorders associated with pain, constipation, or diarrhoea. Myoelectrical activity during 10 hours, including two daily meals, was recorded from eight groups of nickel-chrome electrodes using a 1.5 m length probe introduced by the rectal route. Electromyograms of volunteers consisted of slow waves at two distinct rhythms, approximately 3 and 10 cycles per minute, during 16 to 28% of the recording time respectively for each site. Action potentials were also recorded as 11 to 80 short spike bursts (SSB) per hour lasting 1.5 to 3.5 s at any site and 20-26 long spike bursts (LSB) per hour, lasting 17 to 21 s, occurring in series of four to eight propagated bursts. Additional high-velocity propagated bursts were recorded during the three hour postprandial period. Three typical changes in spike activity patterns were detected: an increase by 170-420% of the number of SSB associated to a high spiking activity was recorded in 13 patients (group I), the absence of SSB, a low spiking activity level and only 3 to 8 LSB per hour (group II), in six patients; and the postprandial response was absent (group III) in three other investigated patients. Evidence for three groups of motor disturbances and their possible relation to clinical manifestations of functional disorders is presented.

Action Potentials↗
PubMed1980

Colonic myoelectrical activity in diarrhea and constipation.

The electrical activity of the colon was recorded during 10 hour sessions from 4 to 8 sets of electrodes carried on a 1.5 m probe in 11 control volunteers and in 35 patients with irritable bowel syndrome manifested by chronic constipation, diarrhea and/or pain. The patterns of electrical spiking activity were compared with that obtained from dogs with induced diarrhea or constipation. In both humans and dogs, two types of electrical activity were identified: short spike bursts (SSB) lasting 0.6 to 2.4 sec and long spike bursts (LSB) lasting 6.4 to 25 sec. The SSBs occurred at a maximum frequency of 13 per min. in man, while the LSB never exceeded 3 per min. Characteristic changes in the myoelectrical activity mainly coincided with disorders. In a group I containing 19 patients, most of them exhibiting constipation, the level of activity was 62% higher than in healthy subjects with an increase in the SSB hourly frequency of 170 to 420%. The colonic activity was similarly increased in constipated dogs. In a group II containing 11 patients suffering from soft feces or watery diarrhea, the LSB activity was significantly reduced. In a group III containing 5 patients, diffuse abdominal pain occurred after eating despite a reduction of the electromotor feeding responses and the absence of colonic postprandial rushes. The results indicate that the functional colonic disorders in man corresponded mainly to 3 specific patterns of myoelectrical activity, one of them (Group I) being reproduced in experimentally constipated dogs.

Action Potentials↗
PubMed1980

[Duality of the myoelectric activity of the colon in the animal].

The electrical activity of the different regions of the colon was recorded from chronically implanted electrodes in six different species. Two types of spiking activity were identified as common to all the species: short spike bursts (SSB), lasting less than 5 sec, occurring in series and localized at one electrode site, and long spike bursts (LSB) of more than 5 sec in duration and propagated over a colonic segment. No relationships were found between the anatomical or feeding peculiarity and the spiking activity of a species. Intense SSB activity was always associated with the formation of dried pellets. The propulsion of digesta seemed to be related to the LSB, their preponderance being associated to the shortest transit times.

Animals↗
PubMed1980

[Veterinary anesthesiology, a pharmacological model (author's transl)].

Different mechanisms are involved in drug interactions, especially between anesthetics and drug administrated before and during anesthesia: liver disease, bioavailability related to the route of administration, displacement of the protein-bound of the part, etc. Two peculiarities of veterinary anesthesiology were found useful to evaluate such drug interactions: changes in the frequency of the cyclic contraction of the reticulum (sheep) and decrease in the central body temperature (cat). These criteria were used in addition to electroencephalographic recordings to appreciate the inhibition of microsomal penthiobarbital metabolism by chloramphenicol, the effect of phenylbutazone on plasma-protein displacement and the non-bioavailability of chloramphenicol by the subcutaneous route.

Anesthesia↗
PubMed1979

Propagation of electrical spiking activity along the small intestine: intrinsic versus extrinsic neural influences.

1. The electrical activity of the small intestine of conscious dog, recorded by means of chronically implanted electrodes, was related to the transit time estimated by phenol red infusion and its propagation observed after a single or double transection and following either isolation or removal of a 50 cm jejunal loop. 2. In the fasted dog, the activity was characterized by the propagation of myoelectric complexes at a velocity of 4 cm/min during which the mean transit time averaged 13 min/m. About 2/3 of these complexes were seen to pass beyond a single section and anastomosis of the jejunum with a delay of 15 min. This number was reduced to 1/3 and the delay doubled when a second section was performed 50 cm distally. 3. In dog with an isolated jejunal loop, most of the myo-electric complexes were seen to pass from the proximal intestine to the loop and then to the intestine beyond the sit of anastomosis within 37 min. Some complexes however passed directly through the anastomosis within 30-32 min, affecting or not the loop. Others started on the loop and/or on the intestine beyond the anastomosis. Finally, the total number of complexes recorded on the distal jejunum was greater than on the duodenum, an effect which disappeared after removal of the isolated loop. 4. The propagation of the complexes occurred at a lower velocity after denervation of a jejunal segment in situ but was arrested in the case of an isolated-denervated jejunal loop. 5. It is concluded that continuity of structures in the bowel is essential for the propagation of a myo-electric complex which is stopped and replaced by another complex at the level of an anastomosis, the number os complexes reorganized beyond an anastomosis and their velocity of propagation depending upon both intrinsic and extrinsic neural influences.

Action Potentials↗
PubMed1979

Perinatal development of intestinal myoelectrical activity in dogs and sheep.

Both slow waves and bursts of spike potentials were recorded prior to birth in dogs and sheep. At 0l7-0.8 of term the slow-wave frequency of the jejunum did not exceed 12/min. It increased in a similar way during the last stage of fetal life in sheep and after birth in dogs. Adult values were attained 10-15 days after birth in the lamb but only by 40 days of age in the puppy. In both species, three stages of development of the spiking activity were identified. Stage 1, termed unorganized spiking activity, was converted in the fetal lamb at 0.8 of term to a fetal pattern (stage 2) characterized by cyclic 3- to 4-min periods of regular spiking occurring at 10- to 20-min intervals and propagated along a short intestinal segment. Stage 3, which corresponds to myoelectric complexes, occurred during the last 10 days of fetal life. In dogs, the fetal pattern (stage 2) was recorded from 5 days before to 15 days after birth. Stage 3 was seen in the 15-day-old neonate. The results suggest that the patterns of electrical activity seen in the last third of fetal life can be related to their function of mixing and absorbing but not expelling intestinal contents. They indicate that the electrical phenomena of the gastrointestinal tract are in accord with the overall greater maturity and independence of the newborn sheep compared to the dog.

Animals↗
PubMed1979

Diet and caecal motility in sheep.

The electrical activity of the caecum was recorded during periods of two months in 5 ewes receiving different diets. For a similar amount of dry matter ingested, the frequency of caecal contractions was diminished on concentrates with urea versus hay ad libitum but not on concentrates without urea. The frequency also decreased when the level of food intake on hay diet or on concentrates without urea diet was reduced. On a daily meal food intake, induced caecal hyperactivity occurred or hay and inhibition for concentrates with urea. The postprandial hyperactivity had a ruminal origin and was mediated by the vagus nerves. The inhibitory effects of urea were correlated with the ruminal production and ammonia and its diffusion into the abdominal cavity.

Ammonia↗