Search PubMed⌕ Search

Biomedical subjects

R Troncone

Publications and source records attributed to R Troncone.

At least 73 records · Page 4Linked to original sources
PubMed1996

In vitro activities of A-gliadin-related synthetic peptides: damaging effect on the atrophic coeliac mucosa and activation of mucosal immune response in the treated coeliac mucosa.

BACKGROUND: Gliadin amino acid sequence(s) responsible for toxicity in susceptible individuals have not been fully elucidated. Previous in vitro studies have suggested the presence of active sequences in the NH(2)-terminal part of the A-gliadin molecule. In this paper the in vitro activity of A-gliadin synthetic peptides 31-55, 31-43, and 44-55 has been investigated. METHODS: Organ culture of jejunal mucosa from untreated and treated coeliac patients was used. In the first system enterocyte height was used as a measure of peptide toxicity; in the second system evidence of activated mucosal cell-mediated immune response was sought. RESULTS: Peptides 31-55 and 31-43 were active on untreated coeliac mucosa at a concentration of 0.5 mg/ml and peptide 44-55 only at a concentration of 3 mg/ml. In in vitro-cultured treated coeliac mucosa peptides 31-55 and 31-43 at 1 mg/ml and peptide 44-55 at 3 mg/ml were able to induce enhanced epithelial expression of HLA-DR and 4F2 molecules and the appearance of CD25 positive cells. CONCLUSIONS: Our results suggest that 31-43 and 44-55 A-gliadin peptides are both active, even if to different extents. In vitro systems remain essential tools to screen material to be subsequently tested in vivo.

Amino Acid Sequence↗
PubMed1996

Diagnostic value of various serum antibodies detected by diverse methods in childhood celiac disease.

The diagnostic performances of antiendomysium IgA detected on monkey esophagus and human umbilical cord smooth muscle, of antireticulin IgA, and of antigliadin IgA and IgG were calculated in 74 children with celiac disease (CD) or other gastrointestinal disorders. We also compared four methods for gliadin antibody detection. With a diagnostic specificity of 100%, diagnostic sensitivity was 94% for antireticulin IgA, 93% for antiendomysium IgA when detected on human umbilical cord smooth muscle, and 97% when detected on monkey esophagus. The diagnostic sensitivity for gliadin antibody was highest with an ELISA procedure, followed by fluorogenic detection (94% for IgG, 91% for IgA, 97% with IgA and IgG combined). Because of its high diagnostic sensitivity and ease and speed of use, the combined antigliadin IgG and IgA antibody assay is suitable for screening large groups of patients. In IgG- or IgA-positive cases, the more demanding and more specific antiendomysium IgA evaluation is required to confirm suspected CD.

Animals↗
PubMed1995

Endomysial antibodies as unreliable markers for slight dietary transgressions in adolescents with celiac disease.

Adolescents with celiac disease often fail to adhere to a strict gluten-free diet. The value of endomysial antibodies in assessing the dietary compliance of such adolescents has been assessed in 23 patients divided into four groups according to their daily gluten intake. Serum endomysial antibodies were absent in all subjects on a gluten-free diet and consistently present in those ingesting > 2 g/day of gluten. Only one of six and three of six teenagers with celiac disease with an intake of < 0.5 and 0.5-2 g/day, respectively, had endomysial antibodies in their serum, despite the presence in three of six and five of six of significant changes in the mucosal architecture, as shown by computerized morphometry of jejunal biopsies. In conclusion, endomysial antibodies cannot be considered a valid marker for slight dietary transgressions.

Adolescent↗
PubMed1995

Metabolic alkalosis due to the use of an oligoantigenic diet in infancy.

A 7-month-old boy on an oligoantigenic diet because of multiple food intolerances presented with anorexia, failure to gain weight and severe hypochloremic metabolic alkalosis with hyperreninemia. Clinical symptoms and biochemical abnormalities disappeared after adequate dietary supplementation with potassium and sodium chloride. This case emphasizes that minimal daily mineral requirements must be provided in infant diets, and highlights the risk of nutritional deficiencies inherent in the prolonged use of oligoantigenic diets not adequately supplemented.

Alkalosis↗
PubMed1995

Latent coeliac disease in Italy. The SIGEP Working Group on Latent Coeliac Disease. Italian Society for Paediatric Gastroenterology and Hepatology.

The term latent coeliac disease applies to patients who have a normal jejunal biopsy while taking a normal diet and, at some other time, before or since, have had a flat jejunal biopsy recovering on a gluten-free diet. Nineteen such patients were identified after a multicentre search conducted under the auspices of the Italian Society for Paediatric Gastroenterology and Hepatology (SIGEP). Serological data and histological material suitable for morphometric analysis were available from 10 and 8 patients, respectively, while they were on a gluten-containing diet. Neither gliadin antibodies nor increased density of intraepithelial lymphocytes are obligate markers of latent coeliac disease; endomysial antibodies are likely to be best predictors of evolution towards villous atrophy. Prospective studies are needed to allow a more precise definition of latent coeliac patient features.

Adolescent↗
PubMed1995

Differentiation of cows' milk intolerance and gastro-oesophageal reflux.

The aim of this study was to compare a non-invasive test of small bowel permeability with a more invasive approach involving endoscopy, mucosal biopsy, and oesophageal pH monitoring for rapidly differentiating gastro-oesophageal reflux (GOR) and cows' milk intolerance in 25 infants with persistent vomiting. Each subject underwent a cellobiose/mannitol permeability study, upper gastrointestinal endoscopy with oesophageal and small bowel biopsies, and a 24 hour pH study. Reflux disease and/or cows' milk intolerance was responsible for vomiting in 24 (96%) of the subjects. Sixteen (64%) of the infants had GOR alone, four (16%) had GOR and cows' milk intolerance, and four (16%) had cows' milk intolerance alone. Morphometric analysis of small bowel biopsies was abnormal in 19% of the patients with GOR alone and in 67% with cows' milk intolerance with or without GOR. The permeability test was abnormal in only 6% of the patients with GOR but in 100% with GOR and cows' milk intolerance and in 100% with cows' milk intolerance alone. The non-invasive permeability study aimed at rapid determination of cows' milk intolerance should pre-empt a more invasive approach in the evaluation of infants with persistent vomiting.

Cellobiose↗
PubMed1995

Cellobiose/mannitol sugar permeability test in children in relation to jejunal morphometry.

The ability of the sugar permeability test to detect minor degrees of mucosal damage is uncertain, particularly in children. This paper reviews experience with the cellobiose/mannitol test at a referral centre of paediatric gastroenterology, relating the results of intestinal permeability to the jejunal morphometry. Two hundred patients underwent the cellobiose/mannitol test at the same time as jejunal biopsy; morphometric analysis of the biopsy specimens was performed by a computerized image analysis system. Increased sugar permeability was revealed in 89%, 80%, 67% and 18% of subjects with subtotal villous atrophy, severe partial villous atrophy, mild partial villous atrophy and normal histological picture, respectively. Nevertheless, once the patients with the most severe changes in their mucosal architecture had been excluded, there was no statistically significant correlation between cellobiose/mannitol ratio and villous and crypt length, villous/crypt ratio and intraepithelial lymphocytes density. The cellobiose/mannitol test is a good indicator of severe mucosal damage; it does not discriminate subjects with minor degrees of mucosal abnormalities, but may give useful indications on the functional state of the jejunal mucosa.

Adolescent↗
PubMed1994

Increased intestinal sugar permeability after challenge in children with cow's milk allergy or intolerance.

The diagnosis of cow's milk allergy or intolerance (CMAI) is based on clinical improvement on exclusion diet and relapse after challenge with milk. The aim of this work was to investigate the value of the cellobiose/mannitol (C/M) sugar permeability test, performed before and after cow's milk challenge, as a tool for the diagnosis of CMAI. Thirty-two patients underwent milk challenge at a median age of 13 months (range 3-84 months). A dual sugar (C/M) permeability test with an iso-osmolar solution was performed before and 24 h after challenge. Of the 10 patients who developed symptoms after challenge, nine showed increased postchallenge C/M ratio, whereas such an increase was observed in only one of the 22 nonrelapsed subjects. The postchallenge C/M ratio increase in relapsed subjects is to be attributed to both higher cellobiose and lower mannitol urinary excretion. These results suggest the use of the sugar permeability test, in addition to clinical observation, as an aid in the evaluation of provocation tests in infants with suspected CMAI.

Animals↗
PubMed1994

Effects of gluten enriched diet on the small intestinal mucosa of normal mice and mice with graft versus host reaction.

This study looked at the effect of extra dietary gluten on the intestinal architecture of both normal mice and those with an ongoing mucosal delayed hypersensitivity reaction. BDF1 normal mice and mice in which a graft v host reaction (GvHR) had been induced, both weaned on gluten free diet, were allocated for three weeks to three different dietary regimens: gluten free, 'normal' (3.6% gluten), and gluten enriched (15.8% gluten). In normal mice receiving the gluten containing diet, shorter villi, deeper crypts, and higher crypt cell production rate were noted when compared with those receiving gluten free diet: these changes were more pronounced in those receiving the gluten enriched diet. GvHR mice showed shorter villi and an increase in both crypt length and crypt cell production rate when compared with normal mice, but the presence of gluten in their diet did not produce additional damage. Both in normal and in GvHR mice receiving gluten containing diet there were no signs of systemic (cell mediated or humoral) or mucosal immune reactions (raised intraepithelial lymphocyte counts or enhanced epithelial Ia expression) to gliadin. In conclusion, increasing the dietary gluten content produces significant changes in the mucosal architecture of normal mice; mice with GvHR enteropathy do not show additional damage resulting from dietary gluten.

Animals↗
PubMed1994

Immunologic and intestinal permeability tests as predictors of relapse during gluten challenge in childhood coeliac disease.

Fifteen children with an initial diagnosis of coeliac disease underwent gluten challenge either because they had never had a jejunal biopsy or because they had had one during the first 2 years of life. The challenge was preceded by a biopsy; clinical symptoms, the cellobiose/mannitol permeability test, and gliadin and endomysial antibody measurement were used to determine the timing of the confirmatory biopsy: it was performed if one test result was repeatedly abnormal or two results were concomitantly abnormal. Gliadin antibodies increased early (already 7 days after the reintroduction of gluten to the diet), but in many cases they returned to normal values thereafter. Increased intestinal permeability to sugars and even more positivity of endomysial antibody were good predictors of histologic relapse. The sequential use of laboratory tests during gluten challenge may significantly shorten its duration.

Autoantibodies↗
PubMed1992

Gliadin induced changes in the expression of MHC-class II antigens by human small intestinal epithelium. Organ culture studies with coeliac disease mucosa.

Jejunal biopsies from 16 treated coeliac disease patients and from nine controls were cultured with and without a peptic-tryptic digest of gliadin. Cultures with a peptic-tryptic digest of maize prolamins were also undertaken. Frozen sections of baseline and cultured mucosa were stained by immunofluorescence with an anti-HLA-DR monoclonal antibody. Before culture the villous epithelium from both controls and treated coeliac disease expressed DR molecules while the crypt epithelium did not. When biopsies from treated coeliac disease were cultured with gliadin the expression of DR was enhanced in the crypt epithelium in eight of 14 cultures and in 11 of 14 was reduced or absent on the villous epithelium. No change was observed in control cultures. We conclude that gliadin is capable of inducing HLA-DR on the crypt epithelium of in vitro cultured coeliac disease mucosa, providing indirect evidence that gliadin may activate cell mediated immune mechanisms within the small bowel mucosa. This model could prove useful in identifying the immunogenic sequence(s) of gliadins and related prolamins.

Celiac Disease↗
PubMed1992

Antigliadin antibody, D-xylose, and cellobiose/mannitol permeability tests as indicators of mucosal damage in children with coeliac disease.

A dual sugar (cellobiose/mannitol) permeability test using an iso-osmolar solution was performed, to compare its ability to predict small-bowel mucosal damage in children affected by coeliac disease with the determination of serum levels of D-xylose and antigliadin antibody. Eighty-three children (67 on gluten-containing diet and 16 on gluten-free diet) were investigated. The D-xylose and the serum antigliadin antibody test predicted accurately 70% and 78% of the small-bowel biopsy results, respectively, whereas the cellobiose-mannitol permeability test predicted 93%. These data confirm the superiority of the permeability test over the D-xylose test, although the former cannot be advocated as a substitute for jejunal biopsy. Our results suggest a complementary use of the permeability test and the antigliadin antibody measurement as screening tests for coeliac disease before applying more invasive procedures.

Adult↗
PubMed1991

Impaired intestinal function in symptomatic HIV infection.

A longitudinal (10-22 month) evaluation of intestinal symptoms and function was performed in five children with symptomatic human immunodeficiency virus (HIV) infection. All received cotrimoxazole, ketoconazole, and immunoglobulins. A search for enteric pathogens and intestinal function tests were repeatedly performed in all patients. Mild episodes of diarrhea were observed in two children. One had cow's milk protein intolerance. Giardia lamblia was found in an asymptomatic carrier. Evidence for impaired intestinal function was found in all patients. These consisted of positive D-xylose and iron oral loads, increased steatorrhea, increased fecal excretion of alpha 1-antitrypsin, abnormal intestinal permeability, and increased food antibody levels. Our results suggest that severe diarrhea may be uncommon in children with HIV infection receiving antimicrobial prophylaxis, but that the intestinal function is frequently, and often markedly, impaired.

Antibodies↗
PubMed1991

Animal model of gluten induced enteropathy in mice.

The aim of our experiments was to produce a local T cell mediated immune response to gliadin in the mouse small intestine as a possible animal model of gluten sensitive enteropathy, coeliac disease. BALB/c and BDF1 mice were immunised systemically with gliadin in complete Freund's adjuvant. The jejunal mucosa was challenged by feeding a gluten containing diet, and villus and crypt lengths, crypt cell production rate, and intraepithelial lymphocyte counts were determined to assess mucosal cell mediated immunity. In some animals permeability and local immunity were modulated by concurrent intestinal anaphylaxis or a graft versus host reaction. There were no changes in the jejunal mucosa of BALB/c mice fed a gluten containing diet after having been parenterally immunized. When, however, mice were parenterally immunised with gliadin, fed a gluten containing diet, rendered hypersensitive to helminth antigen by infection with the nematode parasite Nippostrongylus brasiliensis, and challenged intravenously to produce intestinal anaphylaxis crypt cell production rate was significantly higher than in ovalbumin immunized controls at 12 days after parasite challenge. Finally, graft versus host reaction was induced in BDF1 mice that had been parenterally immunised with gliadin and were on a gluten containing diet. Two weeks later these mice had significantly longer crypts and a higher crypt cell production rate and intraepithelial lymphocyte count than control, unimmunized mice with graft versus host reaction. We conclude that active immunization with gliadin does not in itself produce intestinal cell mediated immunity to gliadin contained in the diet, or enteropathy. Additional factors, such as those occurring during intestinal anaphylaxis (increase intestinal permeability), or during graft versus host reaction (enhanced antigen presentation), seem to be necessary for the full expression of a jejunal mucosal reaction.

Anaphylaxis↗
PubMed1991

Compliance of adolescents with coeliac disease with a gluten free diet.

A cohort of 123 patients with coeliac disease, diagnosed in the first three years of life and followed up for at least 10 years, was reevaluated during the teenage period in terms of compliance with the diet and clinical state. Mucosal structure and lymphocytes were assessed in small intestinal biopsy specimens obtained from 36 subjects, by computerised image analysis. Of these adolescents with coeliac disease, 65% were adhering to a strict gluten free diet, 11.4% were on a gluten free diet but with occasional gluten intake, and 23.6% were on a gluten containing diet. Clinical symptoms occurred more frequently in patients on a gluten containing diet, but not in patients on a semi-strict diet. Occasional intake of small amounts (0.06-2 g/day) of gluten did not produce increased concentrations of antigliadin antibodies but resulted in an appreciably increased crypt epithelial volume and expanded crypt intraepithelial lymphocyte population.

Adolescent↗