Biomedical subjects

C A Reis

Publications and source records attributed to C A Reis.

23 records · Page 2Linked to original sources

PubMed1998

Development and characterization of an antibody directed to an alpha-N-acetyl-D-galactosamine glycosylated MUC2 peptide.

In an attempt to raise anti-Tn antibodies, an alpha-N-acetyl-D-galactosamine glycosylated peptide based on the tandem repeat of the intestinal mucin MUC2 was used as an immunogen. The MUC2 peptide (PTTTPISTTTMVTPTPTPTC) was glycosylated in vitro using concentrated alpha-N-acetylgalactosaminyltransferases activity from porcine submaxillary glands which resulted in the incorporation of 8-9 mol of Ga/NAc. Rabbits and mice developed specific anti-MUC2-GalNAc glycopeptide antibodies and no detectable anti-Tn antibodies. Anti-glycopeptide antibodies did not show reactivity with the unglycosylated MUC2 peptide or with other GalNAc glycosylated peptides. A mouse monoclonal antibody (PMH1) representative of the observed immune response was generated and its immunohistological reactivity analysed in normal tissues. PMH1 reacted similarly to other anti-MUC2 peptide antibodies. However, in some cells the staining was not restricted to the supranuclear area but extended to the entire cytoplasm. In addition, PMH1 reacted with purified colonic mucin by Western blot analysis suggesting that PMH1 reacted with some glycoforms of MUC2. The present work presents a useful approach for development of anti-mucin antibodies directed to different glycoforms of individual mucins.

Animals↗

PubMed1998

Characterization of a panel of monoclonal antibodies using GalNAc glycosylated peptides and recombinant MUC1.

A panel of 56 murine monoclonal antibodies submitted to the ISOBM TD-4 (MUC1) Workshop was analysed for reactivity against nonglycosylated and in vitro GalNAc glycosylated peptides. Twenty-six antibodies reacted with nonglycosylated MUC1 peptides containing 3-5 tandem repeats. The reactivities of most of the antibodies were not affected by GalNAc glycosylation of the peptides. Antibody #147 (decoded as BCP9) reactivity was inhibited when 3 mol of GalNAc per repeat were incorporated in the peptide (at sites T in GVTSA and ST in GSTAP), whereas the reactivity with GalNAc glycosylated peptides with 2 mol of GalNAc per repeat (sites T in GVTSA and T in GSTAP) was unaffected. This is in agreement with the epitope defined as GSTAP.

Acetylgalactosamine↗

PubMed1997

Immunohistochemical study of MUC5AC expression in human gastric carcinomas using a novel monoclonal antibody.

In order to investigate the expression of MUC5AC mucin in normal gastric mucosa and gastric carcinomas, we produced 3 monoclonal antibodies (MAbs) using a MUC5AC synthetic peptide. The immunohistochemical study was performed using one of these MAbs (CLH2) which reacted with the different designs of peptides based on the MUC5AC tandem repeat and with native and deglycosylated mucin extracted from gastric tissues. CLH2 immunoreactivity was restricted to foveolar and mucopeptic neck cells in normal gastric mucosa. No reactivity was observed in type-I intestinal metaplasia. Out of 66 gastric carcinomas, 42 (63.6%) expressed MUC5AC. Most diffuse carcinomas were positive (83.3%), whereas only 59.3% of intestinal and 40.0% of atypical carcinomas expressed MUC5AC (p < 0.05). Gastric carcinomas with mixed pattern showed immunoreactivity in diffuse areas and decreased immunoreactivity in intestinal areas. Every early gastric carcinoma expressed MUC5AC, in contrast to 58.6% of advanced carcinomas (p < 0.05). A trend toward decreased immunoreactivity was observed in deep areas of advanced carcinomas in comparison with the respective superficial areas. Taking together the specific staining of foveolar and mucopeptic neck cells and the absence of immunoreactivity in intestinal metaplasia, we conclude that MUC5AC expression may be used as a marker of gastric differentiation. This assumption is further supported by the finding of MUC5AC immunoreactivity in most diffuse carcinomas, which usually display morphologic and histochemical signs of gastric differentiation. The expression of MUC5AC in early gastric carcinomas, regardless of their histologic type, suggests that all gastric carcinomas retain at least some cells with a gastric phenotype during the first steps of neoplastic development.

Amino Acid Sequence↗

PubMed1997

Loss of a novel mucin-like epithelial glycoprotein in oral and cervical squamous cell carcinomas.

Stratified squamous epithelia of oral and cervical mucosa express high levels of simple mucin-type O-linked carbohydrates, and these are known to undergo structural changes in relation to epithelial differentiation and neoplastic transformation. O-glycans in these epithelia are associated with the cell membrane, but the identity of the carrier molecule(s) remains largely unknown. We report here the identification of a membrane-bound M(r) 200,000-250,000 glycoprotein (gp230) that is expressed in stratified squamous epithelia of the oral cavity. Western blot analysis identified gp230 as a major carrier of simple-mucin type carbohydrate antigens in buccal nonkeratinized mucosal epithelium, suggesting that it may represent a mucin-like molecule. A monoclonal antibody PANH4 defining a protein epitope of gp230 was generated. The PANH4 epitope was localized by immunohistology to suprabasal cell layers of buccal epithelium and was also found in larynx, esophagus, vagina, and exocervix, but not in epidermis. Data showed that gp230 was distinct from MUC1 or CD44. It is interesting that in most cases gp230 was not expressed in squamous cell carcinomas of buccal and cervical mucosa. A few moderately differentiated carcinomas, mainly from cervix, expressed the gp230 epitope. The results suggest that a membrane-bound mucin-like molecule, gp230, is associated with the differentiated phenotype of normal mucosal stratified squamous epithelia and that expression of gp230 generally is lost in severe oral epithelial dysplasia and squamous cell carcinomas of oral and cervical mucosa.

Adult↗

PubMed1995

Poisoning due to illegal use of carbamates as a rodenticide in Rio de Janeiro.

Carbamate insecticides (mainly aldicarb) are illegally commercialized as rat poisons and commonly used by the population of Rio de Janeiro for this purpose. A retrospective study concerning 189 cases (80 men, 109 women) of carbamate poisoning referred to the Poison Control Center of Rio de Janeiro throughout 1993 is described. The causes of carbamate poisoning were suicide attempts (65%) and accidental ingestions (35%). The main signs and symptoms found (86%) were those related to the SLUDGE syndrome (increased salivation, lacrimation, urinary incontinence, diarrhea, gastrointestinal cramping and emesis) which were more commonly seen in adults than in children. Despite treatment with atropine, the case-fatality was 4%. It is concluded that there is a widespread risk of carbamate poisoning in Rio de Janeiro due to its clandestine use as a rodenticide. Effective measures by the government authorities should be implemented to stamp out the illicit commercialization of these compounds.

Adolescent↗