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Biomedical subjects

D Pettijohn

Publications and source records attributed to D Pettijohn.

8 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↗
PubMed1980

Expression of genes coding for non-histone chromosomal proteins in human-Chinese hamster cell hybrids. An electrophoretic analysis.

The non-histone chromosomal (NHC) proteins of several human and hamster cell lines as well as human-hamster cell hybrids were investigated by one- and two-dimensional gel electrophoresis. In each type of human cell, over 90% of the 230 most prominent NHC proteins were indistinguishable electrophoretically from the NHC proteins of the hamster cells. Of the roughly 10% which were distinct, 11 of the proteins may be human-specific, since they were found in each type of human cell examined. The NHC proteins in seven different stable human-hamster cell lines, which, in total, contained markers for 21 of the 24 human chromosomes, were electrophoretically indistinguishable from those of the parental hamster cell line, with the exception of a single protein in one hybrid line. It is concluded that many of the genes coding for the apparently human-specific NHC proteins are not expressed in these hybrid cells. The single exception to this appeared to be a gene coding for a protein of roughly 300,000 daltons. This protein was synthesized in one of the hybrids, as well as in each type of human cell. Since the NHC proteins of the hybrid and hamster cells were virtually identical, there was no evidence for the expression of genes coding for NHC proteins characteristic of the differentiated state of the parental human cells.

Animals↗
PubMed1975

Analysis by isopycnic centrifugation of isolated nucleoids of Escherichia coli.

The isolated, formaldehyde-fixed nucleoid of E. coli has been analyzed by isopycnic centrifugation in CsCl density gradients. The membrane-free nucleoid bands at a density of 1.69 +/- 0.02 g/cm3. The membrane-associated nucleoid bands at a density of 1.46 +/- 0.02 g/cm3. Both species sediment to equilibrium as nearly monodisperse bands in CsCl, suggesting that the nucleoid components of DNA, RNA and protein are present in relatively constant ratios. These ratios are constant regardless of the position of the nucleoids in the heterogeneous sedimentation profile of a preparative sucrose gradient. The fixed nucleoids remain condensed during isopycnic centrifugation and there is no detectable loss of RNA from the nucleoid.

Bacterial Proteins↗