Biomedical subjects

R McCombs

Publications and source records attributed to R McCombs.

4 recordsLinked to original sources

PubMed1997

Decrease in Le(x) expression in esophageal adenocarcinomas arising in Barrett's epithelium.

Fifty esophageal adenocarcinomas were investigated for their expression of Le(a), Le(x), and Le(a)-Le(x). Among the 50 adenocarcinomas, 17 cases developed in Barrett's epithelium. Those 17 differed from the other 33 cases by expressing much less Le(x). Fifty-nine percent of Barrett's adenocarcinomas were Le(x) negative compared with 24% of the non-Barrett's carcinomas. All Barrett's adenocarcinomas showed less than 50% Le(x) whereas 50% of non-Barrett's carcinomas showed between 50 and 100% expression. The statistical correlation coefficient for this association was P < 0.001. Normal gastric cardia epithelium showed the same Le(x) expression in both groups. In the Barrett group, Le(x) expression decreased from normal through intestinal metaplasia and dysplasia to adenocarcinoma. This progression was not seen in the non-Barrett group. Loss of Le(x) expression may prove useful in following patients with Barrett's epithelium in evaluating progression toward a malignant process. No difference in expression of Le(a) and Le(a)-Le(x) was found between Barrett's and non-Barrett's carcinomas.

Adenocarcinoma↗

PubMed1996

Cell-cell interactions influence oligosaccharide modifications on mucins and other large glycoproteins.

Intratumoral phenotypic diversity is well documented with regard to tumor associated carbohydrate antigens (TACA). The factors which control the expression of these cell-surface oligosaccharides on different cells of the same tumor are not understood. We investigated the expression of a panel of mucin associated oligosaccharides in cell lines growing at different surface densities (number of cells per cm2 of growth flask). Results show that the apparent expression of extended Lea-Lex, Lea and Lex, sialyl Lea, Tn and sialyl Tn varies with density of growth by an invasive human squamous cell lung carcinoma cell line (NU6-1), a benign variant (NE-18) and the human lung epithelial cell line BEAS-2B. The results indicate that one of the factors influencing the apparent expression of mucin-associated oligosaccharides is cell-cell interactions.

Antibodies, Monoclonal↗

PubMed1966

Correlation between infectivity and physical virus particles in human cytomegalovirus.

Benyesh-Melnick, Matilda (Baylor University College of Medicine, Houston, Tex.), Fern Probstmeyer, Robert McCombs, Jean P. Brunschwig, and Vladimir Vonka. Correlation between infectivity and physical virus particles in human cyto-megalovirus. J. Bacteriol. 92:1555-1561. 1966.-Infectivity titers [measured as plaque-forming units (PFU)] and particle counts by the sedimentation pseudo-replication technique were determined for crude, unpurified, intracellular preparations of two different strains of human cytomegalovirus. Unlike the high particle-infectivity ratio of 10(6) to 10(8) previously reported for these viruses, the number of total particles per PFU ranged from 160 to 490 with strain AD-169 and from 176 to 1,050 for strain C-87. Interpretation of particle-PFU ratios of intracellular cytomegalovirus in terms of particle morphology is not conclusive at this time. The number of enveloped forms found varied between 0 and 34% of the total particles counted. However, the true proportion is probably greater, because envelopes were found to be destroyed by the enzyme treatment used in preparing the specimens for examination in the electron microscope. The number of full particles found ranged between 4 and 31% of the total particles counted. The particle per PFU ratio of extracellular virus was found to be three- to fivefold lower than that of intracellular virus.

Cytomegalovirus↗

PubMedDate not supplied

Oligosaccharide Le(a)-Le(x): a cell surface marker for carcinomas derived from embryonic endoderm.

An immunohistochemical evaluation of Le(a)-Le(x) expression by adenocarcinomas of the biliary tree, pancreas, colon and stomach was undertaken as examples of epithelial tumors derived from embryonic endoderm. This complements previous studies showing that Lea-Lex was present on the cell surface of non-small cell lung carcinomas, some non-lung carcinomas, and is a prognostic marker for squamous cell lung carcinomas. All of the tumor specimen evaluated were positive and no expression of Le(a)-Le(x) was detected in derivatives of neural, connective or muscle tissues. These findings indicate that it could be informative to examine the biological significance of Le(a)-Le(x) not only in carcinogenesis but during embryogenesis, as well.

Adenocarcinoma↗