E-cadherin gene mutations provide a genetic basis for the phenotypic divergence of mixed gastric carcinomas.

Inactivation of the E-cadherin gene has been described previously in gastric carcinomas. In the present study, we investigated the alterations of the E-cadherin gene in gastric carcinomas and analyzed the relationship between such alterations and the histotypes of the tumors. We performed PCR/single-strain conformation polymorphism mutation screening and loss of heterozygosity analysis of the E-cadherin gene in a series of 26 gastric carcinomas, including 10 "pure" intestinal, 10 "pure" diffuse, and 6 mixed gastric carcinomas, the latter with intestinal and diffuse components.

Differential expression of mucins and trefoil peptides in native epithelium, Barrett's metaplasia and squamous cell carcinoma of the oesophagus.

Background And Aims: In humans, trefoil peptides (TFF peptides) and some mucins have been reported to be expressed in a cell-specific manner at mucosal surfaces of normal gastrointestinal tissues. Neoplastic conditions cause characteristic changes of these expression patterns. To study such patterns in Barrett's metaplasia and squamous cell carcinoma of the oesophagus (SCC), the distribution of MUC1, MUC2, MUC5AC and the three TFF peptides (TFF1, TFF2 and TFF3) was investigated.

Geographic distribution of vacA allelic types of Helicobacter pylori.

Background & Aims: Distinct allelic types of Helicobacter pylori vacA have been defined. The geographic distribution of vacA alleles and cagA was assessed in this study.

Methods: A total of 735 cultures from patients in 24 countries were analyzed by polymerase chain reaction and reverse hybridization on a line probe assay (LiPA).

Intestinal metaplasia of human stomach displays distinct patterns of mucin (MUC1, MUC2, MUC5AC, and MUC6) expression.

Intestinal metaplasia is a well-established premalignant condition of the stomach that is characterized by mucin carbohydrate modifications defined by histochemical methods. The purpose of the present study was to see whether the expression of mucin core proteins was modified in the different types of intestinal metaplasia and to evaluate the putative usefulness of mucins as "molecular markers" in this setting. We used a panel of monoclonal antibodies with well-defined specificities to MUC1, MUC2, MUC5AC, and MUC6 to characterize the expression pattern of mucins.

A family of human beta3-galactosyltransferases. Characterization of four members of a UDP-galactose:beta-N-acetyl-glucosamine/beta-nacetyl-galactosamine beta-1,3-galactosyltransferase family.

BLAST analysis of expressed sequence tags (ESTs) using the coding sequence of a human UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase, designated beta3Gal-T1, revealed no ESTs with identical sequences but a large number with similarity. Three different sets of overlapping ESTs with sequence similarities to beta3Gal-T1 were compiled, and complete coding regions of these genes were obtained. Expression of two of these genes in the Baculo virus system showed that one represented a UDP-galactose:beta-N-acetyl-glucosamine beta-1, 3-galactosyltransferase (beta3Gal-T2) with similar kinetic properties as beta3Gal-T1.

Gastric inflammatory myofibroblastic proliferation in children.

Gastric inflammatory myofibroblastic proliferation (IMP) is an extremely rare entity in children, which to our knowledge has only been mentioned in case reports. We describe the ninth pediatric case and review the literature concerning the etiology, clinical and laboratory features, pathology, treatment, and outcome. There has been a predominance in preschool females.

Typing of Helicobacter pylori vacA gene and detection of cagA gene by PCR and reverse hybridization.

The present report describes an analysis of two virulence genes of Helicobacter pylori. Parts of the cagA gene, as well as parts from the signal (s) and middle (m) regions of the mosaic vacA gene, were amplified with biotin-labelled PCR primers and the products were subsequently analyzed by a single-step reverse hybridization line probe assay (LiPA). This assay comprises a strip containing multiple specific probes for the vacA s region (sla, slb, and s2 alleles), the vacA m region (ml and m2 alleles), and the cagA gene.

Dimeric sialyl-Le(x) expression in gastric carcinoma correlates with venous invasion and poor outcome.

Background & Aims: High expression of sialyl-Le(x) in tumors of different organs correlates with hematogenous metastasis and adverse outcome. Dimeric sialyl-Le(x) expression in gastric carcinoma was evaluated, and its prognostic significance within this setting was determined.

Methods: Dimeric sialyl-Le(x) immunohistochemical expression in 97 gastric carcinomas was analyzed using the FH6 monoclonal antibody.

Determination of the replication error phenotype in human tumors without the requirement for matching normal DNA by analysis of mononucleotide repeat microsatellites.

Microsatellite instability (MI) characterizing tumors with replication errors (RER+ tumors) was first described in colorectal tumors from hereditary non-polyposis colorectal cancer (HNPCC) patients as well as in sporadic cases. It has also been observed in subgroups of extracolonic sporadic tumors, but there is no consensus as to the number of microsatellite loci to examine, and the threshold percentage of unstable loci required to classify a tumor as RER+. We have recently shown that BAT-26, a mononucleotide repeat microsatellite, was quasi-monomorphic in DNA from normal individuals and from colorectal RER- samples, and showed important size variations in RER+ samples.

Expression pattern of gastrointestinal markers in native colorectal epithelium, lesions, and carcinomas.

Three small peptides with a typical cysteine-rich domain (TFF or P-domain) display a specific folding structure (trefoil); they are abundantly expressed on mucosal surfaces of normal and neoplastic gastrointestinal tissues. This epithelial location coincides with mucin secretion and, although not proven beyond doubt, this association is suggestive of their function in maintenance of surface integrity. Using normal colon epithelium, premalignant lesions and tumor samples and specific antibodies we studied expression of these peptides in colorectal carcinomas.

[Family education, a model for allergy prevention].

It is frequent the lack of family adherence toward the therapeutic measures of the allergic diseases. The incidence in the therapeutic non compliance of the asthmatic patients vary from 20 to 80%. In the last decades, the symptomatic expression of the atopic diseases (AD) in the infancy, and in the adolescence of Venezuelans has been transformed into a health care problem, with an inaccessible therapeutic cost for the state and the family.

pS2 protein expression in gastric carcinoma. An immunohistochemical and immunoradiometric study.

The aim of this study was to examine the prevalence of pS2 expression in gastric carcinoma and to determine its prognostic significance. We analysed pS2 protein expression in 50 gastric carcinomas and respective adjacent mucosas by immunohistochemistry and immunoradiometric assay (IRMA). pS2 was consistently expressed in superficial and foveolar epithelium of non-neoplastic mucosa and in 66.

Pattern of pS2 protein expression in premalignant and malignant lesions of gastric mucosa.

The aim of this study was to evaluate the pattern of pS2 protein expression in premalignant and malignant lesions of gastric epithelium. We analysed, by immunohistochemistry, the pS2 expression in six samples of normal gastric mucosa, 18 cases of chronic atrophic gastritis with intestinal metaplasia (IM), 10 hyperplastic polyps, 11 adenomatous polyps and 50 gastric carcinomas, together with the respective samples of adjacent non-neoplastic mucosa. pS2 is expressed throughout foveolar and superficial epithelium of normal gastric mucosa and this pattern is retained in chronic atrophic gastritis out of IM lesions.

Human trefoil peptides: genomic structure in 21q22.3 and coordinated expression.

Trefoil peptides are small secretory proteins characterized by three intrachain disulfide bonds forming the trefoil motif or P-domain. They are abundantly expressed on mucosal surfaces, especially of the gastrointestinal tract. In pathological conditions such as ulcers, metaplasia and neoplasia, their expression is upregulated.

Allele loss in human gastric carcinomas - relation to tumor progression and differentiation.

The sequence of genetic changes associated with the development of gastric carcinoma remains unclarified despite the numerous genetic and chromosomal abnormalities that have been implicated so far in this process. We investigated the frequency and pattern of allele loss in 68 gastric carcinomas, with the aim of identifying genetic changes putatively involved in the histologic differentiation and/or progression of gastric cancer. Allele loss was investigated using 12 RFLP and 11 microsatellite markers localized at 22 different loci from 9 autosomal chromosomes.