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Biomedical subjects

F Andre

Publications and source records attributed to F Andre.

49 records · Page 3Linked to original sources
PubMed1983

Evidence for anaphylactic reactions in peptic ulcer and varioliform gastritis.

The theory of an allergic participation in the pathogenesis of gastric erosions occurring in varioliform gastritis and in peptic ulcer was tested in humans. Biopsies were obtained from the edges of gastric and duodenal ulcers and from the erosion edges of varioliform gastritis as well as from surrounding duodenal, antral and fundic mucosae. Intracellular immunofluorescence staining was used to identify mucosal plasma cells. The lesion edges were characterized by a marked increase of IgE cells. These features justify new therapeutic orientations.

Anaphylaxis↗
PubMed1979

Measurement of glycoprotein content and cell kinetics in preulcerous gastric mucosa.

In an attempt to evaluate the role of gastric mucosal defense factors in ulcerogenesis, we measured the levels of glycoproteins in the mucosa as well as mucosal cell turnover in the preulcerous phase and compared these parameters to the normal mucosa in the same animal. Ovalbumin-presensitized Praomys (Mastomys) natalensis were challenged in the gastric wall with ovalbumin and a gastric ulcer developed at the challenge site 3 days later as a result of a mucosal anaphylactic reaction. This model enabled us to study the events occurring at the site of a future ulceration. Gas-liquid chromatographic determination of mucosal glycoproteins showed that the normal and preulcerous mucosae had similar levels. Cell turnover, determined by [3H]thymidine incorporation, was stimulated as a result of the preulcerous anaphylactic reaction at 24 hours postchallenge whereas at 48 hours the values were not different from those obtained in controls. These results suggest that the pathogenesis of anaphylactic gastric ulcer involves a change in cell turnover but no changes in the production of gastric mucus.

Anaphylaxis↗
PubMed1978

Prevention of experimental anaphylactic ulcer by antigen prefeeding.

Studies were performed in animals to establish whether antigen prefeeding could present homocytotropic antibody synthesis and the induction of gastric ulcer resulting from mucosal anaphylaxis. A single digestive exposure to 1 or 10 mg ovalbumin induced a state of specific immunologic tolerance. Inhibition of the formation of specific reagins was shown by the study of mast cell degranulation. Tolerant animals presented a reduced incidence of gastric ulcer after subsequent mucosal challenge. These results are important for the development of methods of prevention and treatment of allergic diseases.

Anaphylaxis↗
PubMed1975

[Purification of human gastric glycoprotein and a study of its carbohydrate components (author's transl)].

Mucus was extracted from human gastric mucosa by homogenization in distilled water. The crude extract was purified from plasma, salivary and tissue contaminants by different steps involving chromatography on Sepharose 6B, Sepharose 2B and immunosorbents. The native glycoprotein so prepared was found to be immunologically pure; it migrated as a single band in acrylamide agarose gel electrophoresis at pH 8.6 and 3.5. The molecule exhibits blood group acitivity, contains 0.71 per cent sialic acid but no sulphate. The carbohydrate moiety contains glucosamine, galactosamine, fucose, galatose and mannose in the molar proportions 3: 1.95: 2.92:4.53:0.05.

Chromatography, Gel↗
PubMedDate not supplied

Analysis of beta-agonists in urine and tissues by capillary gas chromatography-mass spectrometry: in vivo study of salbutamol disposition in calves.

The fate of salbutamol sulphate given orally has been investigated in calves. The urinary excretion rate and the tissue distribution of this beta-agonistic drug were studied by capillary gas chromatography coupled to low resolution mass spectrometry (GC-LRMS) under electron impact (EI) ionization mode, using an hexadeuterated salbutamol analogue as the internal standard. The parent drug and metabolites were extracted via solid phase extraction (SPE) mixed-phase-containing disposable columns and analysed as their trimethylsilyl derivatives. A more efficient clean-up had to be carried out for tissue samples. An acidic precipitation followed by a liquid-liquid extraction were therefore performed before the SPE. Moreover, the problem of tissue digestion was elucidated by means of an ultrasonic probe. Samples were also analysed before and after enzymic hydrolysis using purified beta-glucuronidase and a mixture of beta-glucuronidase and arylsulphatase, to obtain evidence of phase II conjugation mechanisms. Both free salbutamol and conjugated metabolites were detected in urine and tissue samples. Except for liver or kidney, salbutamol was rapidly cleared from most tissues after a withdrawal period. The possible excretion of some phase I metabolites was also investigated, using further analyses under positive chemical ionization LRMS and high resolution mass spectrometry (HRMS).

Adrenergic beta-Agonists↗
PubMedDate not supplied

Digestive permeability to different-sized molecules and to sodium cromoglycate in food allergy.

Intestinal absorption of mannitol (used as a marker of normal monomer passage) and intestinal absorption of lactulose (used as a marker of macromolecule exclusion) were measured in 15 healthy subjects and in 20 patients with food allergy. When studied in the fasting state, there was no apparent difference in the absorption of mannitol between control subjects and allergic patients although the absorption of lactulose was more marked, but not significantly, in the latter group. Ingestion of an allergen by these patients led to a significant increase in the absorption of lactulose (intestinal passage increased by a factor of two). Administration of 300 mg cromoglycate 1/4 hour before the provocation test completely averted abnormal intestinal permeability. Digestive absorption of cromoglycate was also studied in the same 15 control subjects and 20 allergic patients. The peak plasma concentration and area under the curve were significantly greater in healthy subjects when the study was carried out in the fasting state. The application of an oral provocation test with an allergen also significantly increased the plasma concentration of cromoglycate in allergic patients. Contact between an allergen and the digestive tract in allergic patients therefore leads to an increased intestinal absorption of macromolecules but also to cromoglycate passage, which inhibits allergic reactions.

Adolescent↗