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Biomedical subjects

P Forget

Publications and source records attributed to P Forget.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Modifications of the binding properties of the human VIP receptor of IGR39 cells by sulfhydryl reagents.

The effects of specific sulfhydryl reagents, N-ethylmaleimide (NEM), p-chloromercuribenzoic acid (PCMB) and 5-5'-dithiobis(2-nitrobenzoic acid) (DTNB), were tested on the vasoactive intestinal peptide (VIP) receptor binding capacity of the human superficial melanoma-derived IGR39 cells. On intact cell monolayers NEM and PCMB inhibit the specific [125I]VIP binding in a time and dose-dependent manner while DTNB has no effect at any concentration tested. Inhibitory effects of NEM and PCMB on high and low affinity VIP receptor are not identical. With NEM-treated cells, only low affinity sites remained accessible to the ligand. Their affinity constant is not modified. With PCMB-treated cells, the binding capacity of high affinity sites is reduced by 56% while the binding capacity of low affinity sites is not significantly affected. For both types of binding sites, the affinity constants remain in the same range of that of untreated cells. On cells made permeable by lysophosphatidylcholine, DTNB is able to inhibit the specific [125I]VIP binding in a time and dose-dependent manner. The three sulfhydryl reagents stabilize the preformed [125I]VIP receptor complex whose dissociation in the presence of native VIP is significantly reduced. Labeling of free SH groups with tritiated NEM after preincubation of cells with DTNB and VIP made possible the characterization of reacting SH groups which probably belong to the receptor. Taken together, these data allow us to define three classes of sulfhydryl groups. In addition, it is shown that high and low affinity sites have different sensibility to sulfhydryl reagents.

Alkylation↗
PubMed1991

Effect of inhibiting N-glycosylation or oligosaccharide processing on vasoactive intestinal peptide receptor binding activity and structure.

We used inhibitors of four steps of the glycosylation pathway to examine the contribution of carbohydrate moieties to the ligand-binding activity, cell-surface expression and apparent molecular mass of the human vasoactive intestinal peptide (VIP) receptor. Human melanoma IGR 39 cells, incubated for 60 h with the inhibitors tunicamycin, castanospermine, swainsonine or deoxymannojirimycin, under conditions where cell viability and protein synthesis were not affected, expressed VIP receptor species with different VIP-binding properties. The most pronounced effects on VIP binding were obtained with tunicamycin and deoxymannojirimycin, which respectively caused 80% and 67% inhibition. Treatment with either swainsonine or castanospermine resulted in only a 25-32% decrease in VIP specific binding. Based on Scatchard analyses of data from competition experiments, the decrease in VIP-binding activity in either swainsonine- or deoxymannojirimycin-treated cells was due to a decrease in ligand affinity; the cell-surface number of VIP-binding sites remained unchanged. In contrast, tunicamycin and castanospermine caused decreases in the cell-surface number of functional VIP receptors without affecting affinity. Besides, the drug-treated cells produced VIP-binding proteins with different molecular masses and endoglycosidase H (Endo H) sensitivities. When compared with their counterpart synthesized in control cells, VIP-binding proteins produced by deoxymannojirimycin- or swainsonine-treated cells were smaller in size and exhibited the expected sensitivity to Endo H. No modification in the apparent molecular mass was observed in the presence of either castanospermine or tunicamycin. In addition, after Endo F digestion, all of the deglycosylated proteins migrated with the same electrophoretic mobility. Finally, processing in the presence of castanospermine led to an Endo H-resistant receptor species which showed an unexpected neuraminidase-sensitivity, indicating that, as in control cells, these receptors carry V-linked oligosaccharides with terminal sialic acid residues.

1-Deoxynojirimycin↗
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

Usefulness of random fecal alpha 1-antitrypsin and chymotrypsin determinations in children.

Random fecal chymotrypsin activity and fecal alpha 1-antitrypsin (FA-1-AT) concentrations were determined in 11 children with cystic fibrosis, 5 children with Crohn's disease, 9 children with chronic aspecific diarrhea, 85 children with acute gastroenteritis, and 54 control children. Cystic fibrosis patients showed only very low fecal chymotrypsin values that did not overlap with values obtained in patients with either acute or chronic diarrhea. When compared with our control group, a significant increase of FA-1-AT concentrations was found only in children with Crohn's disease. Normal values were found in all patients with either chronic aspecific diarrhea or cystic fibrosis, while 12 of 85 children with acute gastroenteritis showed FA-1-AT concentrations above the 95th percentile of control children. We conclude that diarrhea (either acute or chronic) does not significantly decrease the clinical usefulness of fecal chymotrypsin activity measurements in the diagnosis of pancreatic insufficiency, while acute (gastroenteritis) but not chronic (chronic aspecific diarrhea, cystic fibrosis) diarrhea can give rise to protein losing and FA-1-AT concentrations similar to those found in Crohn's disease.

Adolescent↗
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↗
PubMed1988

Increased intestinal permeability to (51 Cr) EDTA is correlated with IgA immune complex-plasma levels in children with IgA-associated nephropathies.

Intestinal permeability was investigated in 10 normal young adults, in 11 control children and in 9 children presenting with either Berger disease (4 cases) or Henoch-Schönlein nephritis (5 cases), making use of (51 Cr) EDTA as a probe molecule. All subjects exhibited a normal creatinine clearance at the time of testing. After oral administration of (51 Cr) EDTA, 24-hour urine radioactivity was measured and results were expressed in percentage of the oral dose administered. Means and SD were 2.35% +/- 0.77, 2.51% +/- 0.70, and 5.10% +/- 2.35 for normal adults, control children and patients with IgA-associated nephropathies, respectively. The differences of permeability between controls and patients were statistically significant (p less than 0.01). In addition, a significant, direct, linear correlation has been established between the percentage of (51 Cr) EDTA excreted in 24-hour urine and IgA immune complex-plasma levels. Our results therefore support the hypothesis that increased gut permeability could play a role in the pathogenesis of IgA-associated nephropathies.

Adolescent↗
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)↗
PubMed1986

Is the macroscopic aspect of the esophagus at endoscopy indicative of reflux esophagitis?

Gastroesophageal reflux was looked for in 51 children with chronic obstructive respiratory disease (CORD) using prolonged pH monitoring. An index of reflux aggressivity dependent on both duration and acidity of refluxed material was calculated. This index was significantly related to the macroscopic endoscopic findings, patients with an elevated acidity index having more severe "endoscopic esophagitis" than patients with a normal acidity index. We conclude that the finding of normal, erythematous or destructive esophagitis at endoscopy has at least some clinical relevance.

Adolescent↗
PubMed1986

Serum diamine oxidase in the neonate.

Serum diamine oxidase (DAO) activities were measured in 9 pregnant women and in 33 neonates during the 1st week of life. The radiometric method was used. Very high values were found in the mothers (mean +/- SE: 720 +/- 143 pmol ml-1 h-1). Neonates showed significantly elevated values (mean +/- SE: 178 +/- 54 pmol ml-1 h-1) on the 1st postnatal day when compared to the 7th day values (mean +/- SE: 27 +/- 5.7 pmol ml-1 h-1). Serial determinations showed a progressive decline from day 1 to day 7 after birth. We suggest the high serum DAO levels in neonates during the first days of life are due to leakage of placental enzyme into the circulation either at birth or during fetal life. Consequently, serum DAO cannot be used as a marker of small bowel functional integrity in the 1st postnatal week.

Amine Oxidase (Copper-Containing)↗
PubMed1985

Cow's milk protein allergy and gastro-oesophageal reflux.

Evidence for cow's milk allergy was looked for prospectively in 15 children with recurrent vomiting. Whereas radiological examination showed gastro-oesophageal reflux to be present in all patients, 3 out of 15 children presented an enteropathy associated with an increased number of IgE plasmocytes in small intestinal biopsy tissue. These three patients did not improve with conventional medical therapy but a striking improvement occurred within 24 h on a cow's milk-free diet. We conclude that diagnostic confusion between gastro-oesophageal reflux and cow's milk allergy can occur and that the presence of IgE plasmocytes in small intestinal biopsy tissue indicates IgE-mediated cow's milk protein allergy. All cases of "intractable" gastro-oesophageal reflux should be suspected of cow's milk allergy and investigated accordingly.

Animals↗
PubMed1985

Permeability of the small intestine to [51Cr]EDTA in children with acute gastroenteritis or eczema.

Increased gut permeability to macromolecules is thought to be an important factor in the development of food hypersensitivity. The latter can develop in the course of acute gastroenteritis and could play a role in infantile eczema. We studied gut permeability in 10 normal adults, 11 control children, 7 children with acute gastroenteritis, and 8 patients with infantile eczema, making use of [51Cr]EDTA as probe molecule. [51Cr]EDTA was given orally (50-100 microCi); 24-h urinary excretion of [51Cr]EDTA was measured and expressed as a percentage of the oral dose. Mean and standard error were 2.35 +/- 0.24, 2.51 +/- 0.21, 9.96 +/- 3.44, and 10.90 +/- 2.05 in normal adults, control children, and gastroenteritis and eczema patients, respectively. Differences between controls and either gastroenteritis (p less than 0.001) or eczema (p less than 0.001) patients are significant. Our results support the hypothesis that increased gut permeability could play a role in food hypersensitivity.

Acute Disease↗
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↗