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Biomedical subjects

J F Grenier

Publications and source records attributed to J F Grenier.

At least 19 recordsLinked to original sources
PubMed1992

Variations of magnesium, iron, copper and zinc during the colonic wound healing process: experimental study on rabbits.

The role of trace elements in the wound-healing process is still controversial. Their variations within a normal colonic wound healing have never been studied. An experimental study on rabbits was designed to study magnesium, iron, copper and zinc variations in blood, normal colonic walls and colonic anastomoses on each of the first 7 postoperative days. No major variations of Mg could be observed. Fe decreased in blood as well as in colonic walls and anastomoses. Cu increased in blood, whereas it decreased in colonic walls and anastomoses. Zn decreased in blood, whereas it increased in colonic walls without significant changes in anastomoses. The role of Fe seemed to be rather difficult to understand. Plasma mobilization seems to explain the local use of Zn, while early tissue release with further return in blood occurred for Cu. The importance of a well-balanced nutritional status is underlined to prevent and correct the variations of trace elements in the postoperative course.

Anastomosis, Surgical↗
PubMed1991

Autonomous telemetric capsule to explore the small bowel.

An intestinal telemetric capsule has been developed to study the small bowel in man. It consists of a cylinder (11 mm in diameter and 39 mm in length) containing a location detector, a radiotransmitter, a lithium battery and an interchangeable tip. After having been swallowed by the patient, the capsule passes through the whole gut and is recovered in the stools. During the transit through the small bowel, the information provided by the radiotransmitter allows continuous monitoring of the distance covered from the pylorus, the direction and the velocity of progression. Moreover, according to the type of interchangeable tip, it is possible, by remote control, to sample 0.5 ml of intraluminal fluid for subsequent analysis or to release 1 ml of any liquid substance in a precisely determined place for pharmacological studies. The main originality of the capsule is its ability to transmit its precise location inside the small bowel.

Gastrointestinal Motility↗
PubMed1991

[Intestinal absorption of insulin with a new telemetric shuttle in dogs].

Telemetric shuttles for the in vivo investigation of the gastrointestinal tract have been available for sometime. We describe herein the use of a new shuttle model whose original features include: a) continuous, real time transmission of its location in the small bowel and accurate measurement of the gut length, b) controlled release of 1 ml of a given substance at any chosen site, allowing detailed investigation of intestinal absorption at different levels of the small bowel under physiological conditions. Small bowel length was measured in dogs using the shuttle and was later compared to the actual small gut length measured in the same animals at laparotomy. The telemetric measurements appeared to closely match the direct operative measurements. Insulin absorption from the canine small bowel was then investigated releasing different dosages of insulin together with the pancreatic enzyme inhibitors Soybean and Aprotinine and a surfactant (5-methoxysalicylate). By adjusting the dose of insulin released, the type of adjuvant substance delivered with it and the site of release in the small bowel, we have been able to precisely define the conditions of insulin absorption. Insulin as such is exclusively absorbed in the ileum when released in doses of 500 IU or higher and mixed with aprotinine. For absorption to take place the solution delivered by the shuttle needs to have the correct pH and natremic concentration.

Animals↗
PubMed1990

Long-duration stress. Immediate and late effects on small and large bowel motility in rat.

No extensive information exists in literature concerning the late or residual effects of stress on motility of small bowel and colon. Moreover, the duration and magnitude of the intestinal motor response to stress are still ignored. Therefore, the aim of our work was to determine, in rat, the effect of long-duration stress induced by restraint on the motility of small bowel and colon. Observations were made during physical restraint and 60 h later. Bipolar electrodes were implanted on the gastrointestinal serosa from the pylorus to the sigmoid colon in male Wistar rats. Electromyographic (EMG) recordings were made during fasting state, and a control EMG recording session was performed during 12 hr, followed by a 12-hr recording during restraint stress. After a 60-hr resting period, another EMG recording session was performed during 3 hr. During stress in the pylorus and small bowel, the recurrence of migrating myoelectrical complexes (MMCs) was immediately interrupted and replaced by a continuous and irregular activity. The motility index (number of spike bursts/10 min) was augmented rapidly on the jejunum and ileum, but it increased only gradually on the pylorus. Only on the transverse colon were the number of spike bursts/hour and their relative duration increased after 7 hr of physical restraint. In contrast, the sigmoid colon displayed a gradual decrease in the relative duration of contractile activity during the first 6-7 hr of stress. At 60 hr after stress in the pylorus and small bowel, a normal control motor activity was restored (MMC, motility index) on the jejunum and on the ileum, but the motility index on the pylorus was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Improvement in the healing of colonic anastomoses by vitamin B5 and C supplements. Experimental study in the rabbit].

To study the effects of vitamins B5 and C on the healing process of colonic anastomoses, 3 groups of 20 rabbits were given daily either placebo (group A), or vitamin B5 (100 mg/kg: group B) or vitamin C (100 mg/kg: group C). After 8 days of supplementation, via a midline incision and under general anaesthesia, 2 colonic segments were removed, and the continuity was restored. On the 3rd post-operative day, the rabbits were killed and the anastomoses were removed. Mechanical properties of both normal colon and anastomoses were determined by using bursting pressure tests, number of burst anastomoses, fibroblast count, hydroxyproline concentration and determination by microanalysis of trace element content: Mg, P, S, Ca, Fe, Cu, Zn and Mn. Vitamin B5 (p = 0.03) and vitamin C (p less than 0.01) both decreased the number of burst anastomoses. Furthermore the required bursting pressure values were higher with vitamin C (p = 0.01) than in controls. Both vitamins restored normal Zn levels at the anastomotic site, whereas these levels decreased on the 3rd post-operative day during the normal healing process of colonic anastomosis. Moreover, vitamins B5 and C increased Fe, Cu and Mn levels, which are intimately all involved in collagen synthesis. Vitamins B5 and C enhance the colonic wound healing process in the rabbit, acting together in synergy in vivo as well as in vitro, as previously demonstrated.

Anastomosis, Surgical↗
PubMed1990

[Difference in the action of prostaglandin E2 (PGE2) on longitudinal circular muscle contractions of the colon. Experimental study in dogs].

The effect of prostaglandin E2 (PgE2) on the circular and longitudinal contractions of the canine colon was studied in chronic conditions. A mechanical transducer developed in our laboratory and implanted on the canine colon collected simultaneously and separately the variations of length in two perpendicular directions. The recordings started at the 6 postoperative day. The colonic motility was recorded two hours before (as control period) and two hours after the intravenous injection of PgE2 at three different doses: 0.1-1.0 and 10 micrograms/kg. PgE2, at the three doses, induced, progressively over time, a significant decrease in duration and amplitude of the circular contractions, while the amplitude of longitudinal contractions remained unchanged. 10 micrograms/kg of PgE2 immediately induced a significant increase in the duration of longitudinal contractions followed by a decrease in this value during the 2nd hour after PgE2 administration. Each dose of PgE2 shortened the period of recurrence of longitudinal contractions, inducing rapid or immediate bursts of contractions. This effect was moderate or absent for the circular contractions. It is concluded, that PgE2 has different actions on circular and longitudinal contractions of the colon. According to the dose used, it induces hypokinesia (relaxation) in the circular muscle and premature strong contractions in the longitudinal motor activity.

Animals↗
PubMed1979

An automated continuous flow procedure for the determination of enterokinase.

A continuous flow method has been developed for the automatic determination of enterokinase in rat small intesstine mucosa and/or luminal content. Trypsinogen was first hydrolysed by enterokinase under conditions which minimize autocatalytic activation. L-benzoyl-arginine paranitroanilide was then added and split to paranitroaniline by the trypsin so formed. Liberated paranitroalinine was diazotized and converted by the Bratton-Marshall reagent (N-naphthyl ethylene diamine) to an azodye, with maximum absorption at 550 nm. This method of determination was found to be six times more sensitive than the direct p-nitroaniline determination method. 36 determinations can be made hourly.

Animals↗
PubMed1979

Intestinal brush border enzymes and chronic alcohol ingestion.

The effect of graded (5, 10, 20, and 50%) chronic ethanol administration on the intestinal brush border enzymic activities has been investigated in the rat at three levels of the intestinal tract (duodenum, jejunum, ileum). Ethanol has been administered for 8, 15, 30, and 90 days. A 30% to 50% decrease of sucrase and alkaline phosphatase results, showing that the effect of alcohol appears in the first 8 days of intoxication is not reversible after 8 days of an alcohol-free diet. The effect of ethanol is not limited to disaccharidases. Impairment of alkaline phosphatase, peptidases and also enterokinases is observed. The decrease is more marked in the duodenum and jujunum than the ileum. The decrease of enzymic activity is generally maximal after 30 days of intoxication. There is then little further deterioration or even significant improvement. At the 30th day of ethanol administration, a clearcut dose-response relationship has been established. The results obtained suggest that ethanol exerts an effect on the intestinal mucosa which is not directly correlated to morphological villus changes.

Alcoholism↗
PubMed1979

[Vasoactive intestinal peptide (VIP) in the Verner-Morrison syndrome (author's transl)].

An early diagnosis of the Verner-Morrison syndrome will greatly enhance the chances of curative resection. There is a striking need for a simple diagnostic test. A number of suggestions have been made for the presumed hormone mediator of this syndrome. Numerous reports have led to a wide acceptance that vasoactive intestinal peptide (VIP) is the responsible mediator for the pharmacologic actions of this peptide are similar to the physiological characteristics noted in the watery diarrhea syndrome. A raised plasma VIP concentration, on the other hand, would suggest the presence of a tumour. These observations argue for the radioimmunoassay measurement of plasma VIP in a patient with the watery diarrhea syndrome.

Adenoma, Islet Cell↗
PubMed1979

[Islet cell transplantation and diabetes (author's transl)].

It is now apparent that transplantation of islet cells is biologically feasible in experimental animals utilizing adult neonatal or fetal islet cells and employing many different sites for implantation of the islet cells. It is reasonable to expect that with successful acquisition of new basic information in immunology, endocrinology, metabolism and developmental biology islet cell transplantation should be used as a therapeutic approach to human diabetes.

Animals↗
PubMed1979

Developmental pattern of rat intestinal brush-border enzymic proteins along the villus--crypt axis.

At various postnatal stages, intestinal epithelial cells were isolated sequentially from villus tip to crypt base by successive EDTA treatments. According to the localization of marker enzymic activities, isolated cells were pooled into three cell compartments: villus (V), lower villus and upper crypt (VC) and crypt (C). Purified brush-border-membrane proteins were separated by 7.5%-polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. Enzymic activities could be assigned to some protein bands: maltase/glucoamylase (protein band 3), sucrase-isomaltase (protein bands 3 and 6), lactase (protein band 5) and alkaline phosphatase (region of protein bands 8 and 9). The findings suggest the following. (1) Sucrase-isomaltase activities appeared in compartment C at 17 days with a simultaneous increase of the pre-existing protein band 3 and appearance of a well-defined protein band in position 6; the enzymic complex remained still present in the crypt cells until adulthood. From the day 21 onwards, sucrase-isomaltase was detected in compartments VC and V. (2) Lactase was only present in the three cell compartments until day 21; at this developmental stage its activity completely disappeared from compartment C, in spite of the persistence of a weak protein band. (3) Alkaline phosphatase activity could be detected as a single peak corresponding to protein band 9 in all three cell compartments until day 21; thereafter it was replaced by two peaks of activity showing a less precise correlation with the well-defined protein bands 8 and 9. In the crypt cells of the adult rat, however, the preweaning situation, which was regularly observed, is an unexpected phenomenon. (4) Maltase and glucoamylase did not display any marked qualitative or quantitative modifications either along the villus-crypt axis or during the period of postnatal development studied. Evidence is given from the present data that each brush-border enzyme investigated has a specific developmental pattern.

Age Factors↗
PubMed1979

Computer program for intestinal spike bursts recognition.

A FORTRAN program has been developed for locating intestinal spike bursts and for estimating their strength. Tested against human scanning, the reliability rate was 92% and the misrecognition rate was 2.5%. This program was applied to the automatisation of the Migrating Myoelectric Complex analysis. A first method computed the percentage of Basic Electrical Rhythm (BER) cycles with superimposed spike bursts. A second one was based on the evaluation of spike bursts strength.

Animals↗
PubMed1979

In vivo exploration of the tensile strength of the abdominal wall after repair with different prosthetic materials. Experimental study in the rat.

The problem of parietal herniation seems to be a simple mechanical one for which there should be a safe method of repair. In the present study, the bursting strength of abdominal wounds was explored by mechanical investigation and the repair process evaluated at a cellular level by quantitative microscopy. Both methods of investigation show that mesh materials have advantages over nonporous cloth materials in the repair of large defects of the abdominal wall.

Abdominal Muscles↗
PubMed1979

Turnover studies of human intestinal brush border membrane glycoproteins in organ culture.

Turnover in organ culture of human small intestinal membrane glycoproteins was measured by the pulse-chase technique, using 14C-glucosamine, 14C-fucose or 14C-leucine as tracers. Apparently, low degradation rates were found for the major high-molecular-weight proteins which co-migrated on SDS-polyacrylamide gels with maltase-glucoamylase, lactase-phlorizin-hydrolase and sucrase-isomaltase enzymic activities. In contrast, an unidentified glycoprotein appearing on gels next to alkaline phosphatase exhibited a higher degradation rate with an apparent half-life of about 30 h, this being similar to the half-life of total glycoprotein as measured in mucosal homogenates. The results obtained with the pulse-chase technique were confirmed by double isotope experiments using 14C-leucine and 3H-leucine as tracers. These findings indicate that in organ culture there is a low basic turnover of human intestinal membrane glycoproteins which co-migrate on gels with known glycosidase enzymic activities.

Cell Membrane↗
PubMed1979

Chick embryo pancreatic transplants reverse experimental diabetes of rats.

The effectiveness of xenogeneic embryonic tissue in the treatment of experimental diabetes has been investigated in rats. The splenic lobes (80) of 15- to 18-d-old chick embryos, composed almost exclusively of endocrine tissue, were implanted directly into the hepatic parenchyma of the rat recipient. The biochemical and metabolic changes in the recipients suggest that embryonic transplants of 15-d-old chick pancreases were able to significantly improve, for a prolonged period of time (18 mo), the diabetic state of nonimmunosuppressed rats. None of the recipients of 18-d-old embryos splenic lobes exhibited a long-term improvement of the diabetic state after transplantation. The complete destruction of the pancreatic B cells of the recipients was assessed by: (a) immunocytochemical investigations of the recipient's pancreas, (b) measurement of insulin in the liver and pancreas of the recipients and (c) in situ vascular perfusion of their pancreas submitted to high glucose challenge. The results suggest that pancreatic tissue of the 15-d-old embryos is immunologically immature lacking one or several lymphocyte subsets implicated in the afferent lood of "non-self" recognition.

Animals↗
PubMed1979

Effects of oral and parenteral corticosteroids on intestinal villous morphology and brush border enzymes in the rat.

The effects of corticosteroid have been studied in rats submitted to oral administration of prednisone (5 mg. per kg. per day) during 8, 15, 30, and 90 days. The results were compared to those obtained after parenteral administration of hydrocortisone acetate (50 mg. per kg. per day intramuscularly). The morphometric changes of the villus-crypt axis and the brush border enzymic content of the mucosa (sucrase, enterokinase, alkaline phosphatase, and aminopeptidase) were the parameters investigated at the duodenal, jejunal, and ileal levels. Oral administration of prednisone resulted in a significant increase of the duodenal villous height at the 15th (+ 13 per cent, p less than 0.01), 30th (+ 33 per cent, p less than 0.001), and 90th day (+ 56 per cent, p less than 0.001), whereas in the jejunum a constant decrease of the villous height was noted. Parenteral hydrocortisone administration did not affect intestinal morphology. Effects of oral corticosteroids on the microvillous enzymic activities were related to both intestinal level and duration of corticoids administration: (1) in the duodenum increase of sucrase, alkaline phosphatase, and aminopeptidase during 30 days followed by normalization at the 90th day, (2) an initial increase of sucrase, alkaline phosphatase, and aminopeptidase limited to the first 8 days in the jejunum, and (3) a significant rise of alkaline phosphatase (greater than 100 per cent, p less than 0.001) and enterokinase (greater than 100 per cent, p less than 0.001) in the ileum at the 15th day of treatment. Parenteral corticosteroid administration was associated with a significant increase of both sucrase and enterokinase activities. The present study suggests that: (1) Corticosteroids exert a direct effect on the intestinal morphology varying with the intestinal level and duration of treatment. (2) No correlation could be established between anatomic and functional changes. (3) Oral corticosteroids exert an enhancing effect of the brush border enzymic activities, even in the adult mucosa and particularly at the ileal level where they stimulate significantly the enterokinase mucosal activity. (4) Parenteral corticosteroids exert a more specific effect limited to sucrase and enterokinase enhancement.

Administration, Oral↗