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At least 1,423 records · Page 79Linked to original sources
PubMed1985

A simultaneous flow cytometric assay for c-myc oncoprotein and DNA in nuclei from paraffin embedded material.

A simultaneous flow cytometric assay for the c-myc oncoprotein and DNA in nuclei extracted from archival paraffin wax embedded clinical biopsies is presented. The nuclei were extracted by pepsin digestion after dewaxing 20 micron sections. The c-myc oncoprotein was probed with a mouse monoclonal antibody. This was raised against a synthetic peptide corresponding to a hydrophilic region of the protein predicted from the amino acid sequence. The technique is illustrated with biopsies from patients with testicular cancer and with benign and malignant neoplasms of the colon.

Antibodies, Monoclonal↗
PubMed1994

Comparison of flow cytometric DNA content analysis of fresh and formalin-fixed paraffin-embedded solid neoplasms.

In an attempt to compare results of fresh and fixed tissue flow cytometric DNA analysis we analyzed paraffin blocks of 87 solid tumors; 67 of these were DNA aneuploid and 20 were DNA euploid by fresh flow cytometric analysis. Forty-two aneuploid tumors and all diploid tumors were concordant (71.3% concordance), whereas 25 of 67 (37%) aneuploid tumors appeared diploid on fixed tissue analysis. Reasons for discordance included loss of small aneuploid peaks, merging of G1/G0 peaks of diploid and aneuploid stemlines giving a broad G1/G0 peak, and masking of near-tetraploid aneuploid peaks by the G2/M peak in fixed tissue. S-phase fraction could be determined in 51 of 67 (76%) aneuploid cases analyzed fresh and 29 of 42 (69%) concordant aneuploid cases analyzed from fixed tissues. All parameters were consistently higher in the fixed tissue: S-phase fraction (mean = 18.29% versus 12.82%), coefficient of variation of diploid G1/G0 peak (5.62% versus 2.11%), and DNA index (1.79 versus 1.69). We conclude that significant differences exist between flow cytometric data obtained from analysis of fresh versus fixed tissues and therefore prognostic correlations made on the basis of results of fixed tissue flow cytometric analysis may not necessarily parallel those of fresh tissue studies.

Aneuploidy↗
PubMed1981

Cellular localization of 2-[3H]deoxy-D-glucose from paraffin-embedded brains.

Results of experiments in which regional neuronal activity is revealed by a 2-[3H]deoxy-D-glucose (3H-2-DG)-paraffin section-emulsion autoradiography method are described. The trigeminal pathway of freely behaving mice was activated differentially by selective patterns of whisker removal. One hour after injection of concentrated 3H-2-DG, the animals were perfused systemically with a periodate/lysine/paraformaldehyde mixture (McLean, I. W., and P. K. Nakane (1974) J. Histochem. Cytochem. 22: 1077-1083), the brains were embedded in paraffin, and serial sections were taken and coated with emulsion for autoradiography. Diffusion of the isotope out of the tissue was assessed visually and by liquid scintillation counting. While substantial loss of 3H isotope into the embedding fluids (about 95%) was found, the scintillation counts and the autoradiograms showed good fixation of the isotope in situ, no evidence of isotope movement into the emulsion, and no gradients of diffusion in the sectioned material. Patterns of regional labeling were similar to those reported from brains prepared by conventional 2-[14C]deoxy-D-glucose (14C-2-DG) autoradiography; for instance, auditory and vestibular pathways in the brainstem were heavily and specifically labeled. Trigeminal structures associated with the intact (stimulated) whiskers were labeled relatively heavily, indicating that label uptake is specific with respect to neuronal activity. In the cortex, the patterns of label corresponded directly and precisely to those barrels known to receive inputs from the intact whiskers. Distribution of silver grains in the cortex and in the brainstem was correlated directly with neuronal profiles, including processes, some of which were identified by means of a Nissl counterstain. Clearly, this approach offers considerable technical advantages, in particular, the ease with which the histological material is prepared. The resolution of the autoradiograms and the quality of the histology are excellent.

Animals↗
PubMed2000

Mutation analysis of the p53 tumor suppressor gene using paraffin-embedded specimens of human transitional cell carcinomas by the direct sequencing method.

A very small quantity of DNA was extracted from paraffin sections of 25 bladder and 2 ureteral cancer cases, and exons 5-8 of the p53 gene were amplified by the polymerase chain reaction. Mutations were detected by direct sequencing, and their relationships to clinicopathological factors were assessed. Point mutations of the p53 gene were observed in 2 of 27 specimens of transitional cell carcinoma. One was a novel nonsense mutation. The prognosis of patients with p53 gene mutations was poorer than those of patients without mutations. Analysis of the data showed that assessment of the potential malignancy of bladder cancer, combined with a conventional pathological diagnosis, allows a more precise prognosis. Direct sequencing of tissue specimens enables swift prognostic evaluation and prompt decisions concerning treatment.

Adult↗
PubMed1993

DNA flow cytometry of fresh and paraffin-embedded tissue using cytokeratin staining.

DNA flow cytometry measurements were performed using cytokeratin as a second parameter to identify epithelial cells selectively in fresh and in archival paraffin samples of normal and adenocarcinoma tissues from breast and colon. Fresh specimens consisted of 22 adenocarcinomas of breast, 20 adenocarcinomas of colon, 16 control breast samples, and 13 control colon samples. Paraffin block specimens consisted of 22 adenocarcinomas of breast (the same as fresh samples), 20 adenocarcinomas of colon (the same as fresh samples), 37 control breast samples and 34 control colon samples. The average proportion of cytokeratin-positive cells per group ranged from 31 to 55% for fresh samples and from 14 to 34% for paraffin samples. For aneuploid cells populations of adenocarcinomas, which consist only of epithelial cells, the average percentage of cytokeratin-positive cells ranged from 60 to 72%. The technique gave satisfactory measurements of ploidy and of cell cycle data in both types of samples. Cell cycle measurements were less accurate than ploidy measurements in both types of samples, and multiple sampling will be required for adequate accuracy. The average S-phase fraction of cytokeratin-positive cells ranged from 6 to 15% for fresh specimens and from 11 to 20% for paraffin samples. Similar data were obtained for the proliferative index (G1 + S + G2 + M phases). The coefficients of variation were smaller for proliferative index than for S-phase fraction data, indicating greater accuracy. Paraffin data give higher cycling cell measurements than corresponding fresh data, so separate standardization of measurements may be required for fresh and for paraffin data.

Adenocarcinoma↗