Biomedical subjects

G Dandrifosse

Publications and source records attributed to G Dandrifosse.

At least 37 records · Page 2Linked to original sources

PubMed1996

Effects of a single dose of orally-administered spermine on the intestinal development of unweaned rats.

Investigations were undertaken to obtain information on the mechanism by which orally administered spermine induces postnatal maturation in the rat intestine. Suckling rats ingested one dose of spermine (8 mumol) then were sacrificed at different intervals. -A. Proximal and distal parts of the intestine were homogenised. -B. A modification of the Wieser's technique was used to isolate cell fractions from the proximal mucosa. Wet weight and length of intestine; protein content, DNA amount, disaccharidase activity, polyamine amounts in intestinal and cellular extracts were measured. Spermine ingestion induced two phases of events: first, a cellular desquamation then a new cell differentiation. In the isolated epithelial cells, two and four hours after spermine ingestion, modifications in lactase and maltase specific activity were recorded, as were variations in spermine, spermidine and putrescine content. These observations clarify the cellular and molecular events of the intestinal development occurring after spermine ingestion and open new research perspectives.

Administration, Oral↗

PubMed1996

Polyamine and intestinal properties in adult rats.

We questioned whether polyamines coming from the diet or produced by intestinal microflora or by intracellular metabolism influence intestinal functions. Therefore, we compared pathogen-free rats and germ-free rats receiving a diet with low polyamine content and either treated or not treated with difluoromethylornithine (DFMO) and/or methylglyoxal bis (guanylhydrazone) (MGBG). Wet weight, protein content, DNA content, sucrase (EC 3.2.1.48), maltase (EC 3.2.1.20) and lactase (EC 3.2.1.23) specific activities, amounts of putrescine, spermidine and spermine were measured in the mucosa of the proximal and distal intestine. Body weight was also determined. Rats without microflora had a higher specific activity of maltase and higher amounts of spermidine and spermine but lower lactase specific activity than pathogen-free animals; the low-polyamine diet given to germ-free rats had little effect on the functional variables measured (decrease of maltase and lactase specific activities) and did not modify the amounts of polyamines. DFMO and/or MGBG administered to germ-free rats receiving a low-polyamine diet induced modifications of most of the variables studied. Body weight and wet weight of proximal and distal intestine decreased, disaccharidase specific activities decreased, and amounts of polyamines changed according to the inhibitor used. Thus, our results showed that the deprivation of polyamine supply from microflora or from the diet failed, under our experimental conditions, to affect the intestinal properties analysed but exogenous and endogenous polyamine restriction altered general properties of the organism as well as intestinal functions.

Animals↗

PubMed1995

Validation of creatine, glycogen and L-(+)-lactate determination in biopsy samples of bovine Musculus diaphragma.

Whereas reliable measurements of diaphragmatic force and electrical activity are now available in calves, evidence that substrate contents in the bovine diaphragm can be accurately measured is still lacking. The purposes of the present study were therefore a) to describe and test the reliability of methods and procedures used for sampling, lyophilisation, extraction and dosage of muscular lactate, glycogen and creatine contents and b) to report the variation in their levels found along the bovine diaphragm and among individuals. The repeatability of the results yielded by a) assaying the extracts, b) processing and assaying the extracts and c) taking samples at different sites in the muscle was assessed. Neither assay, nor processing effects were significant (P < or = 0.05). Substrates were found to be homogeneously distributed within the two muscles studied. Substrate contents expressed per unit of muscle weight or total creatine were neither more or less variable than when expressed per unit of dry matter.

Animals↗

PubMed1994

Response of rat immature enterocytes to insulin: regulation by receptor binding and endoluminal polyamine uptake.

BACKGROUND/AIMS: The mechanism(s) by which insulin stimulates enzyme expression in rat immature enterocytes are unknown. The purpose of this study was to investigate these mechanism(s). METHODS: The effects of insulin or an antireceptor monoclonal antibody (RPN 538) were assessed on microvillous enzyme activities and the endoluminal uptake of [14C]spermine. Changes in de novo synthesis of polyamines were measured by mucosal ornithine decarboxylase activity. RESULTS: In sucklings (day 14), administration of insulin failed to induce intestinal ornithine decarboxylase activity, whereas in older rats (day 18 and 20), ornithine decarboxylase was enhanced by 2-2.5-fold. Immature enterocytes from sucklings, pretreated with alpha-difluoromethylornithine, remained sensitive to insulin and expressed enzyme activities at levels equal to controls. In response to insulin, the uptake of [14C]spermine and the mucosal concentrations of spermine and spermidine were increased by 30%, 13%, and 39%, respectively. Administration of RPN 538 had no effect on [14C]-spermine uptake, but it prevented the effects of endogenous insulin on enzyme expression. CONCLUSIONS: The enzymatic response of immature enterocytes to insulin is mediated by binding of the hormone to its receptor and is transduced into the cell without de novo synthesis of polyamines. The regulation by insulin of the endoluminal uptake of spermine could be critical for intestinal maturation.

Adrenalectomy↗

PubMed1994

Intestinal development in suckling rats: direct or indirect spermine action?

The present investigation addresses the question of whether spermine orally given to unweaned rats directly or indirectly exerts its effects on the intestinal brush border disaccharidases and if the adrenal gland secretions play a role in this phenomenon. The results showed that spermine, surgically placed in the lower part of the distal small intestine, induced sucrase, stimulated maltase-specific activity and decreased lactase-specific activity in both proximal and distal segments of the small intestine. Introduction of spermine into the lumen of the large intestine stimulated the specific activities of disaccharidases in the whole small intestine. Intraperitoneal injection had no effect except a slight reduction of lactase-specific activity in the distal intestine. Adrenalectomy prevented the oral effect of spermine on sucrase- and maltase-specific activity but not on lactase-specific activity. Addition of spermine to intestinal explants in organ cultures fails to reproduce any of these effects. It even reduced maltase-specific activity. These findings suggest that dietary polyamines have either direct and indirect effects on properties of rat immature intestine.

Adrenal Glands↗

PubMed1994

Spermine-induced precocious intestinal maturation in suckling rats: possible involvement of glucocorticoids.

The mechanism(s) involved in the spermine-induced precocious postnatal maturation of the intestine in the unweaned rat was examined. Spermine given orally to 11-day-old rats stimulated ACTH and corticosterone secretion. Maximum serum levels of ACTH and corticosterone were observed between 4 and 6 h after spermine ingestion and were five- and sevenfold greater respectively than those of control rats receiving saline alone. Intraperitoneal injection of the polyamine had no effect on corticosterone production. Repeated intraperitoneal administration of gastrin, cholecystokinin, glucagon(1-37) and secretin to 11-day-old rats had no effect on the specific activity of intestinal disaccharidases. These data indicate that (1) the hypophysial-adrenal axis is implicated in the postnatal development of the gastrointestinal tract induced by spermine and (2) spermine affects ACTH and corticosterone secretion indirectly, probably by stimulating the release of gastrointestinal hormone(s).

Administration, Oral↗

PubMed1993

Evolution of biochemical parameters characterizing the proximal small intestine after orally administered spermine in unweaned rats.

Important variations in intestinal biochemical characteristics were recorded after ingestion of a single dose of spermine (8 mumol 50 microliters-1 water) by rats which were 11 days old. Two phases of events were observed. During the first hours which follow spermine administration, we mainly noted: -a decrease in the weight of DNA and of intestine per cm, -a decrease in the specific activity of lactase and of maltase, -an increase in the spermine content. The second phase of events started about 30 h after spermine ingestion. We observed: 1. An increase in the weight of DNA and of intestine per cm; 2. The appearance of sucrase activity; 3. An increase in maltase specific activity; 4. An increase in spermidine content; 5. tendency to normalization of the spermine content. The epithelial cells of the proximal intestine were isolated in fractions from the top of the villi to the bottom of the crypts. Two hours after spermine administration, we noted: 1. An increase in the lactase specific activity of the epithelial cells located at the top of the vili; 2. A decrease in the activity of the cells situated at the lower part of the crypts; 3. An increase in the specific activity of maltase contained in the different categories of enterocytes, except in those from the bottom of the crypts; 4. An increase in the content of putrescine present in the epithelial cells of the whole axis excepted in the bottom of the crypts; 5. An increase in the spermidine and spermine content of all the cell fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1992

Polyamine concentration in rat milk and food, human milk, and infant formulas.

The polyamine concentration in rat milk and food, human milk, and infant formulas was estimated by HPLC. In rat milk, the concentration of putrescine and spermine was low (generally under 2.5 nmol.mL-1 for putrescine and under 1 nmol.mL-1 for spermine). The spermidine concentration was higher and seemed to increase during lactation. The rat food was richer in polyamines than the rat milk (about 150 times for putrescine and spermine, about 30 times for spermidine). We already proved that ingestion of spermine or spermidine can induce precocious maturation of the rat intestine. The present observations suggest that polyamines contained in rat food could play an important role in postnatal maturation of the rat intestine. The polyamine concentration of human milk was measured from 60 different mothers during a period extending from the 1st wk to the 6th mo of lactation. Great variation was observed. During the 1st mo of lactation, the general pattern was as follows: putrescine concentration generally varied little (from 1 to 3 nmol.mL-1), spermine and spermidine concentrations showed a similar pattern (the highest values appeared at the end of the 1st wk of suckling). After the 4th mo of lactation, putrescine concentration increased slightly, whereas spermine and spermidine concentration stayed almost stable. The concentrations of polyamines in 18 powdered milks for babies were estimated. Spermine and spermidine contents were lower than those in human milk. A protective effect of spermine or spermidine against alimentary allergies is suggested.

Animal Feed↗

PubMed1991

Effects of environmental temperature and exercise on the biochemical characteristics of hamster intestine.

The effects of increasing environmental temperature and of exercise on some biochemical characteristics of the intestinal mucosa were analyzed in hamsters to determine whether damage occurs to the intestine during exercise, because long-distance runners complain of cramp, diarrhea, or retrostaltic symptoms, especially when exercise is performed at high temperatures. Two sets of experiments were carried out on groups of five animals. First, one group stayed at rest at 20 degrees C while another group performed exercise for 30 min at the same temperature. Second, one group of animals remained at rest at 20 degrees C for 16 h, a second group was placed at 32 degrees C for the same period, and a third group was subjected to the latter treatment but in addition performed two 20-min exercises. The animals were killed immediately after the experiment. After the small bowel was removed, biopsies were taken for histological examination, and the remaining small bowel tissue was homogenized for biochemical analysis. During exercise performed at 20 degrees C or during exposure to 32 degrees C, the DNA weight (expressed as a function of the protein weight) increased; the specific activity of sucrase, leucine aminopeptidase, diamine oxidase, and maltase decreased; spermine and putrescine content generally decreased; and the weight of mucosal proteins per length of intestine did not vary significantly. When exercise was performed at 32 degrees C, we noted few modifications in the values of the intestinal parameters tested, i.e., changes in only the weight of mucosa expressed as a function of bowel length and, perhaps, the spermine or putrescine content.

Acclimatization↗

PubMed1990

Reversibility of spermine-induced intestinal maturation in the rat.

In the present investigation, the reversibility of spermine-induced precocious intestinal maturation was studied. Neonatal rats received either saline or spermine (4 mumol, twice daily) solution orally on the 11th and 12th postnatal day. They were killed on the 13th, 14th, 15th, 16th, and 17th postnatal days. After the small bowel was removed, it was either divided into three equal parts or prepared for electrophoretic analysis. Histological examination, protein content measurement, and disaccharidase activity estimation were performed on each part of the intestine. Spermine administration was shown to induce structural and mucosal enzyme changes characteristic of postnatal maturation. This phenomenon, which was generally clearly observed in 13- and 14-day-old rats, then became less apparent in 15- and 16-day-old animals. Differences were noted according to the segment of intestine or the biochemical parameter analyzed. When rats were 17 days old, no significant differences generally existed between control and spermine-treated rats. If the 140- to 150-kDa proteins, isolated by electrophoresis, are assumed to represent the subunits of the sucrase-isomaltase complex, the results obtained indicate that spermine induces a modification of the concentration of this complex. When compared to values obtained in adult rats, the concentration of the complex was approximately three times higher in spermine-treated 13-day-old rats, while no differences were found in spermine-treated 14-day-old rats. Further, similar concentrations were found in control and spermine-treated rats with an age of 17 days. These results suggest that spermine-induced precocious intestinal maturation is reversible when spermine treatment is stopped.

Animals↗

PubMed1989

Effect of methotrexate on the intestinal mucosa of PGE2-treated rats.

In the present study, we aimed to protect the intestinal mucosa from small bowel damage in methotrexate (MTX)-treated rats. The protective effect of prostaglandin E2 (PGE2) was investigated. Ileal integrity was evaluated making use of different biochemical parameters: content of sucrase and maltase activities, contents of DNA, proteins, AMPc, PGE2, putrescine (Put), spermine (Spm) and spermidine (Spd). Rats were orally administered 0.5 ml of NaCl solution (0.9%) containing or not containing 400 micrograms.ml-1 of PGE2 twice daily, during three or ten days. Half an hour after the 18th ingestion of PGE2, 0.5 ml of NaCl solution (0.9%) containing MTX (16 mg.ml-1) was injected intravenously. Rats were killed exactly 48 hours after this injection. MTX had no effect on the Put content, increased the AMPc content and decreased the contents of DNA, proteins, Spm, Spd, PGE2 and sucrase or maltase activity. PGE2 had no effect on the biochemical parameters we studied, except on the contents of DNA (10-day treatment) and of PGE2 (3- and 10-day treatment). When MTX was injected after PGE2 treatment, as compared with what was observed when MTX was used as reported above, we observed--an increase in spermine content after 3-day PGE2 treatment and- an increase in the contents of DNA, Spm, Spd and disaccharidase activity after 10-day PGE2 treatment. No other significant variation in the other biochemical parameters was recorded, whatever the duration of the PGE2 treatment. These results indicate that PGE2 could partially protect the intestinal mucosa against the biochemical effects of MTX. Other experimental conditions may need to be chosen in order to obtain a better cytoprotective effect of PGE.

Amine Oxidase (Copper-Containing)↗

PubMed1989

Evolution of some biochemical characteristics of the intestinal mucosa during the first postnatal weeks in C57 mice. Effects of thyroxine and putrescine.

In C57 mice, during the third week after birth, there is a rapid conversion of the intestinal epithelium from fetal to mature adult status. Some characteristics (lactase, maltase, diamine oxidase, and sucrase activity; putrescine, spermine and spermidine concentrations; mitotic index) have been analyzed for the proximal, middle, and distal parts of the intestine in mice of different ages: 8, 15, 19, and 60 days. The most important observations recorded were as follows: (a) sucrase- and maltase-specific activities as well as spermine and spermidine contents increased abruptly on the 19th postnatal day and then decreased; (b) decrease of lactase and diamine oxidase-specific activity was recorded between the 15th and 19th postnatal days, (c) later, diamine oxidase-specific activity increased, whereas putrescine content decreased in the proximal part of the intestine; and (d) mitotic index was not significantly different when estimated for the crypts on days 11 and 19. No similar variations of these biochemical parameters were observed over a period of 3 days when mice were injected with thyroxine on the 8th day or when mice received putrescine per os on the 9th day, as explained in the text. Only a slight but significant variation in sucrase- or maltase-specific activity with thyroxine and a variation of the lactase or DAO-specific activity of the distal part of the intestine with putrescine were recorded.

Amine Oxidase (Copper-Containing)↗

PubMed1988

Spermine and spermidine induce intestinal maturation in the rat.

In the present study, we aimed to induce precocious intestinal maturation in neonatal rats by the oral administration of polyamines. Groups of 5 rats received either saline, spermidine (10 mumol daily), or spermine (6 mumol daily) orally on the 12th, 13th, and 14th postnatal days. The rats were killed on the 15th postnatal day. After the small bowel was removed, a 1-cm distal ileal segment was removed for histologic examination and the remaining small bowel tissue was homogenized for further biochemical analysis. Polyamine administration was shown to induce structural and biochemical mucosal changes characteristic of postnatal maturation. Lactase, sucrase, and maltase specific activities (micromoles of substrate hydrolyzed per minute per gram of protein) were 80 +/- 10, 10 +/- 3, and 116 +/- 19 for the saline-treated rats; 51 +/- 7, 34 +/- 2, and 315 +/- 37 for the spermidine-treated rats; and 25 +/- 2, 46 +/- 5, and 419 +/- 63 for the spermine-treated rats, respectively. Similar results were obtained with rats, first treated with spermine (6 mumol) on the 7th postnatal day, receiving spermine (6 mumol) daily as described above and killed on the 10th postnatal day. Dose-response experiments performed as reported above in rats whose treatment began on the 12th postnatal day showed that the maturational effects of orally administered spermine are dose-dependent.

Age Factors↗

PubMed1987

Effect of prostaglandin E2 on the small intestine of indomethacin-treated rats.

In the present study, the protective effect of PGE2 on intestinal damage in indomethacin-treated adult rats was investigated. Ileal integrity was evaluated making use of different biochemical and histological parameters: activities of sucrase, maltase and diamine oxidase; concentrations of DNA, putrescine, spermidine and spermine; incorporation of 3H-thymidine into DNA; mitotic index and mucosal thickness. Results expressed per g of mucosal weight, showed that: maltase and diamine oxidase activities as well as DNA, spermidine and spermine concentrations decreased markedly in indomethacin-treated rats when compared to control rats; the decrease of maltase activity as well as DNA, spermidine and spermine concentration was less pronounced in PGE2-treated rats when compared to indomethacin-treated rats; 3H-thymidine incorporation into DNA and mitotic index values showed no significant variation in the course of different treatments; mucosal thickness increased strongly, in PGE2-protected rats. We suggest that PGE2 could protect the rat's intestinal mucosa against the effects of indomethacin through a trophic action on intestinal villi.

Amine Oxidase (Copper-Containing)↗

PubMed1985

Lactase insufficiency revisited.

The definition of "insufficient" small bowel lactase activity varies greatly among authors. The present study is aimed at redefining lactase insufficiency by comparing intestinal lactase activity and results of the lactose breath hydrogen test. Primary "insufficient" lactase activity was considered to be present when a child with a normal small bowel histology showed lactose malabsorption as measured by the lactose breath hydrogen test. The lactase activity of 22 "normal" children ranged from 0.77 to 4.57 U/g wet weight, while five children showed primary lactase insufficiency as defined above. Small bowel lactase activity in the latter patients was less than 0.74 U/g wet weight. Sucrase and maltase activities were similar in both groups of patients. We conclude that children with a normal small bowel histology should be considered to have primary lactase insufficiency when small bowel lactase activity is below 0.75 U/g wet weight.

Adolescent↗

PubMed1985

Serum diamine oxidase activity in acute gastroenteritis in children.

Serum diamine oxidase (DAO) activities were measured in 20 control patients and in 24 patients with gastroenteritis. Results (mean +/- SE) were as follows: 1) control patients (n = 20), 36.2 +/- 5.7 pmol h-1 ml-1; 2) gastroenteritis (acute phase) (n = 11), 31 +/- 4.9 pmol h-1 ml-1; 3) gastroenteritis (healing phase) (n = 21), 18 +/- 1.9 pmol h-1 ml-1. Patients with gastroenteritis in the healing phase had significantly lower DAO values when compared to control patients (p less than 0.001) and to gastroenteritis patients in the acute phase (p less than 0.05). In eight patients where both acute and healing phase values could be measured, a significant decrease between acute and healing phase was found (p less than 0.001). Patients with severe gastroenteritis tended to have lower DAO activity values than patients with moderate gastroenteritis (p = 0.10). Our results support the hypothesis that serum DAO activity is a marker of the total mass of functional enterocytes, the decrease of which during gastroenteritis is reflected in a decrease of serum DAO activity values.

Acute Disease↗

PubMed1984

Analysis of dansyl derivatives of di- and polyamines in mouse brain, human serum and duodenal biopsy specimens by high-performance liquid chromatography on a standard reversed-phase column.

The concentrations of putrescine, spermine and spermidine were measured in human serum, children's duodenal biopsy specimens and mouse brain homogenates by high-performance liquid chromatography. The chromatographic analysis was performed on dansyl derivatives of the polyamines using a reverse-phase system with an ion-pairing retention mechanism (heptane sulphonate). Capacity factors were determined at different concentrations of acetonitrile. Simple linear gradients were set up for fast (15 min) or routine (25 min) analysis. Three fluorescence detectors were compared for these determinations and their detection limits determined. The minimum detectable amount of polyamines was 25 fmol compared to 500 fmol with standard detectors. While samples prepared from tissues did not require a high sensitivity, a detector of better performance was needed to assay the polyamines in human serum.

Animals↗

PubMed1984

High-yield synthesis of a [3H]ethylenediamine ditetrodotoxin derivative.

[3H]Tetrodotoxin [( 3H]TTX) and a [3H]ethylenediamine derivative of TTX are the most widely used ligands for the study of the Na channel. The former ligand presents a low specific radioactivity (1 Ci/mmol) while the latter is highly labeled (30 Ci/mmol). However, its two-step synthesis, i.e., mild oxidation followed by coupling of [3H]ethylenediamine, has been described with a low overall yield of 1.7%. In this work, more favorable experimental conditions are defined for the limiting reaction, i.e., the oxidation step, using [14C]testosterone as a model molecule. Applied to the oxidation of tetrodotoxin, this procedure produces yield values of 30-50%, as determined by high-performance liquid chromatography. Moreover, two oxidized TTX molecules appear to be covalently linked to [3H]ethylenediamine, yielding a new labeled tetrodotoxin derivative with a specific radioactivity of 45 Ci/mmol and a dissociation constant of 0.6 nM for electroplax membranes.

Animals↗