Comparison of absorption measurements of DNA stain content by utilizing video and scanning image cytometers

Fluorescence array detector for large-field quantitative fluorescence cytometry

A prototypic fluorescence array detector (FAD) has been designed and constructed which is capable of quantifying single-cell fluorescence emissions from a statistically significant population of cell-sized objects (over 10(3)) on a solid substrate. The system is comprised of a cryogenically cooled CCD, 50 mW air-cooled argon ion laser, and optics that image a large (1 x 1 cm) field at 1:1 (no magnification). The CCD is effectively treated as a two-dimensional array of 2.7 x 10(5) independent 20 x 20 microns photodetectors, with each cell-sized object imaged across only a few CCD pixels. Algorithms have been developed for focusing, image segmentation, shading correction, and noise rejection; performance data for the FAD with fluorescent calibration beads are presented. The FAD is a simple alternative to microscope-based imaging cytometry, allowing large-field imaging without a scanning stage.

Evidence for altered cell-cycle traverse of the non-modal cells of the heteroploid MCa-11 line

Classic stem cell theory states that the growth of heteroploid cell populations is due to the proliferation of 'main stemline' cells with modal DNA content and chromosome number. Cells with non-modal DNA content and chromosome number are thought to be blocked and/or destroyed at mitosis. To test this, we studied two chromosomally stable cell populations (mouse bone marrow and WCHE-5 cells) and one heteroploid, chromosomally diverse cell line (MCa-11). The heteroploid MCa-11 cells showed significant [3H]dT labelling for cells with DNA contents below the modal G0/G1 peak and above the modal G2 peaks (P < 0.001). This was consistent with the presence of cells with the non-modal DNA content that were engaged in replicative DNA synthesis. A percentage labelled mitosis analysis showed that MCa-11 cells with non-modal DNA content and chromosome number were able to complete mitosis, although with prolonged pre-karyokinetic time. These results suggest that many non-modal cells present in heteroploid cell populations are capable of continued proliferation.

A comparison of flow cytometric and absorption cytometric DNA values as prognostic indicators for pancreatic carcinoma

BACKGROUND

The DNA content of 30 adenocarcinomas of the head of the pancreas was measured by flow and absorption cytometric analysis.

METHODS

Each of the patients in this study had curative pancreatoduodenectomy. The absorption cytometric measurements were done in a research laboratory, and the flow cytometric measurements were performed in a commercial laboratory. The DNA measurements were done on nuclei disaggregated from pancreatic cancer tissue blocks without the examiner knowing whether the patient had survived.

RESULTS

Twenty-one of the 30 cancers were found to be aneuploid by absorption cytometric analysis, whereas only 1 of the 30 cancers was aneuploid by flow cytometric analysis. This difference was statistically significant (P < 0.001).

CONCLUSIONS

Univariate and multivariate analyses showed that the absorption cytometric DNA measurements were stronger prognostic determinants for patient survival than were the flow cytometric DNA measurements, indicating that some caution may be warranted in the interpretation of commercially obtained DNA distributions of pancreatic carcinomas.

Non-random distribution of abnormal mitoses in heteroploid cell lines

We have performed absorption-cytometric DNA measurements of the DNA contents of the G0/G1, G2, metaphase, and telophase cells of the heteroploid MCa-11 and HL-60 lines, as well as the WCHE-5 line which has a narrowly restricted number of chromosomes. We found that morphologically unbalanced mitoses occurred much more frequently in telophase-cell pairs of the heteroploid MCa-11 and HL-60 lines than in those of the chromosomally stable WCHE-5 line. Furthermore, the morphologically unbalanced mitoses represented unequal segregation of DNA into each of the daughter telophase nuclei. Such mitotic segregation errors (MSE) occurred almost exclusively in telophase cells with DNA contents which were above, or below, the DNA content of the modal telophase population. The net effect of these non-random, unblanced divisions of heteroploid cells with non-modal DNA contents is to produce one daughter cell with a DNA content that tends to return to the modal DNA content peak.