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Biomedical subjects

G Devroede

Publications and source records attributed to G Devroede.

At least 55 records · Page 3Linked to original sources
PubMed1977

Correlation of variations in intraluminal pressure and potential differences in the perfused colen.

To investigate the nature of variations in the large intestine potential differences, a continuous perfusion of isotonic saline was carried out in the colon of 14 rats. Intraluminal pressure and potential differences between the lumen and the peritoneal cavity were continuously and simultaneously recorded, while impedance of the system and respiration were also constantly monitored. To obtain a quantitative evaluation of the data, Fast Fouier Transform was performed on the signals and their derivatives which were auto- and cross-correlated. While there was no obvious relation between pressure and potential in the unperfused colon, there was clear visual qualirative evidence that, during steady state conditions of perfusion, an increase in intraluminal pressure was accompanied by a decrease in potential differences, while impedance of the recording system remained unchanged. Computer analysis disclosed four narrow ranges of stable frequencies for both pressure and potential. They were centred around 0-3, 1-75, 10-7, and 75 cycles per minute, the latter being synchronous with respiration. It is concluded that the variations of potential differences recorded during perfusion, a well-know phenomenon, are not electrical artefacts: the fast rhythm is probably induced by respiration, which increases intracolonic pressure and that, in turn, reduces the absolute value of potential differences, which remain negative mucosa versus serosa. The slower rhythms are synchronous for pressure and potential. Mechanisms responsible for the decrease in potential related to the increase in pressure remain unknown.

Animals↗
PubMed1977

Effects of saline infusion and acute metabolic acidosis and alkalosis on water and electrolyte transport in the human colon.

Both the kidney and colon secrete bicarbonate and transport water and electrolytes. The respective contributions of these two organs to acid-base and electrolyte balance in normal man has thus been studied in eight healthy male volunteers who underwent simultaneous renal clearance studies, and colonic perfusion with a 0.9% saline or 7.2% mannitol solution, during metabolic alkalosis and acidosis, extracellular volume expansion, and control conditions. There was no influence of these acid-base conditions on electrolyte transport in the colon. In the urine, preferential loss of chloride over sodium averaged 81, 143 (P less than 0.001), and 141 (P less than 0.05) muequiv./min, during control, metabolic acidosis, and extracellular volume expansion conditions, respectively. During alkalosis more sodium than chloride was lost (146 muequiv./min) (P less than 0.001). Colonic pH averaged 7.41 during saline and 6.75 (P less than 0.005) during mannitol perfusion. Titratable acid was not produced in the colon during saline perfusion, and averaged 18 muequiv./min during mannitol perfusion. Urinary titratable acid increased from 19 to 25 muequiv./min (P less than 0.01) during volume expansion. With saline perfusion, bicarbonate secretion rate in the colon rose from 249 muequiv./min during control conditions to 289 muequiv./min during metabolic alkalosis (P less than 0.05). More bicarbonate was excreted in the urine during alkalosis when mannitol was introduced in the colon (243 muequiv./min) than when saline was perfused (152 muequiv./min) (P less than 0.05). This study indicates that the response of the human colon is trivial compared with that of the kidney during acute changes in acid-base balance.

Acid-Base Equilibrium↗
PubMed1976

Manometric assessment of continence after surgery for imperforate anus.

Of 49 children with imperforate anus, 23 underwent an abdominoperineal procedure for a high and seven for a low maliformation, 17 had a perineoplasty for a low and two for a high malformation. In each subject, rectal and anal sphincteric resting pressures were studied at least 1 yr after surgery. Of 30 subjects who had undergone an abdominoperineal procedure, eight were continent in contrast to 15 out of 19 patients who had had a perineoplasty (p less than 0.001). In patients who had undergone an abdominoperineal procedure, the rectal motility was of the colonic type, with waves of higher amplitude and lower frequency (p less than 0.01) than in the normal rectum in 23 cases and in most of these, peristalsis was recorded down to the anal margin. Incontinence was most frequently associated with abnormally short anal resistance, low anal pressure, reduced sensibility, weak voluntary contraction and absence of rectoanal inhibitory reflex. In the group of patients who underwent perineoplasty, continence was associated with normal mechanical parameters and normal physiologic behavior of the anal sphincter.

Adolescent↗
PubMed1976

Relationship between viscoelastic properties of the rectum and anal pressure in man.

Viscoelastic properties of the rectal wall and anal sphincter pressure were studied simultaneously in 25 normal children. During rectal distension for 60 s, with varying volumes of air, the rectal pressure varied as the sum of two exponential functions of the time plus an asymptotic constant. A rectoanal inhibitory reflex was elicited during these distensions. The exponential decrease of the rectal pressure corresponded exactly to the return of the upper anal canal pressure to the resting value in some subjects. In others, the upper anal canal remained relaxed as long as the rectal ampulla was distended, except with smaller volumes. The results obtained may be explained by an analogical rheological linear model.

Anal Canal↗
PubMed1976

Intraluminal pressures during perfusion of the human colon in situ.

Nine healthy human volunteers underwent colonic perfusion and recording of the intraluminal pressure simultaneously in the right, transverse, and left colon. Isotonic saline was infused into the caecum at various flow rates from 10 to 30 ml per min. During colonic perfusions, pressure waves were simple and distorted only by respiratory artifacts. Their amplitude was large (10 to 44 cm of H2O), of long duration (8 to 68 sec), and of low frequency (0.2 to 1.8 wave per min). The frequency of the waves was very stable and this stability was uninfluenced by the site of recording and the rate of perfusion. A pressure wave in the right colon was always followed within 3 sec by a wave in the transverse and left colon. The frequency and amplitude of the waves increased in all subjects and at all rates of perfusion from right to left colon (P less than 0.001). The wave frequency increased with the perfusion flow rate (P less than 0.001). The relationship between the perfusion flow rate and the waves amplitude was curvilinear (P less than 0.01). It is concluded that in the human colon perfused in situ there is a gradient of motility preventing aboral propulsion. This study suggests that during perfusion, liquids are trapped in the right colon. Data on transport of water and electrolytes, obtained from whole colon perfusion, may in fact reflect events occurring in the proximal part of the large bowel.

Adolescent↗
PubMed1976

Computer-aided diagnosis of gastroenterologic diseases in Sherbrooke: preliminary report.

To assess the diagnostic accuracy of a computer-aided-diagnosis system when implemented in different parts of the world, an automated system, which had established its reliability in Leeds, England, was transferred to Sherbrooke, Quebec. In this preliminary study two retrospective series, comprising 104 patients with acute abdominal pain and 101 patients with dyspepsia, were drawn from the files of the Centre Hospitalier Universitaire in Sherbrooke. The history and physical-examination sheet was analyzed, coded and tested against the Leeds data base on a WANG 2200 computer, and the results were compared with the final Sherbrooke pathologic diagnosis. Overall the computer made a correct diagnosis in 78.8% of cases of acute abdominal pain and 70% of cases of dyspepsia. Computer diagnoses of appendicitis were correct in 97% of cases and the system recognized 91% of the actual appendicitis cases. Similar figures for cholecystitis were 91% and for peptic ulcer, 87%. However, the "pick-up" rate by the computer of pancreatitis was only 25%. It is concluded that geographical differences in disease presentation will probably not impair the validity of the computer method used in this study. A comparison of various diagnostic methods and levels of competence will await a prospective trial of this method.

Abdomen↗
PubMed1976

The genesis of bowel sounds: influence of viscus and gastrointestinal content.

This study was undertaken to try to solve the controversy about the influence of gastrointestinal contents on the genesis of bowel sounds, and to probe the respective importance of the various abdominal viscera. Eleven healthy volunteers were intubated by mouth with a multiple-lumen tube. Bowel sounds were recorded for 10 min when the tube was in the stomach, the upper jejunum, and the cecum, while it was left intact in situ, or perfused with isotonic saline (15 ml per min), or with an equal (7.5 ml per min of each) mixture of isotonic saline and air. Using a previously developed method, a computer analysis was made of the recording without any human intervention during the treatment of data. An analysis of variance demonstrated that the effect of perfusion varied according to site, with 46% of counted sounds while the tube was in the stomach, 32% in the jejunum, and 22% in the colon (P less than 0.05). There were two types of sounds: some exceeded in amplitude a preset threshold, and thus were picked up by the computer, but their average absolute value for 20 msec remained inferior to another preset threshold. Their number was kept in memory (NS--sounds having an amplitude exceeding a threshold S1, expressed in number per 10 min). A second type of sounds also exceeded the present threshold but their average absolute value for 20 msec also exceeded another preset threshold. Their number (NE--sounds having an amplitude exceeding the thershold S1 but having also a 20-msec average amplitude above another threshold S2, expressed in number per 10 min) was also memorized. The latter group was composed of two types of sounds: some had a limited spectrum of low frequency (100 Hz) and were of high amplitude and short (congruent to 5 msec) duration (NE1); some others had a higher and more dispersed frequency centered around 300 Hz (NE2). Fifty per cent of high energy (NE) sounds appeared while the tube was in the stomach, 30% in the colon, and 20% in the jejunum (P less than 0.005). Short and high amplitude sounds (NE1) were counted more often (43%) when it was in the colon than in the stomach (38%) and the jejunum (19%) (P less than 0.025), and this was confirmed (P less than 0.005) by a study of the ratio of NE1/NE. On the contrary, higher frequency sounds (NE2) were present more often when the tube was in the stomach (59%) than in the jejunum (24%) and in the colon (17%) (P less than 0.005). There was no influence of the presence of the unperfused tube on the genesis of bowel sounds in different sites (P greater than 0.05). In the stomach and the colon perfusion of the air/saline mixture increased the number of sounds (P less than 0.025) and all types of sounds in the stomach (P less than 0.025), whereas in the jejunum it was the perfusion of saline which increased them (P less than 0.025). It is concluded that the stomach is the most active site of production of bowel sounds, followed by the colon and then the small bowel, that sounds differ in different sites, and that all this is influenced by viscus content.

Cecum↗
PubMed1975

Crohn's disease of the vulva.

Three patients with Crohn's disease primarily involving the large intestine had unusual abscesses of the vulvar area. At biopsy, the abscesses had classic features of the primary disease and were clearly separated from the intestinal tract. There was no fistula in the anal canal, and the perineum between the vulvar abscess and the anus was normal. One of the patients also had an early lesion of Crohn's disease in the sigmoid. The lesion appeared as a small erythematous spot without ulceration. Biopsy revealed a typical granuloma under an intact mucosa. It is concluded that Crohn's disease is not confined to the gastrointestinal tract, and that early lesions of the disease within the gastrointestinal tract are submucosal rather than mucosal.

Abscess↗