Preparation of tissues for DNA flow cytometric analysis

Esophageal metastasis from a peripheral lung carcinoma masquerading as a primary esophageal tumor

A 65-year-old man presented with progressive dysphagia, which proved to be the first clinical manifestation of a peripheral lung carcinoma (secondary to a submucosal metastasis in the esophagus). The lung tumor, hidden by the diaphragm on chest x-ray, was not suspected until a thoracotomy was done. Although dysphagia is known to be the first manifestation of bronchogenic carcinomas, such presentation in a case of a peripheral lung carcinoma has not been well described. This case is reported with a review of the literature for cases with dysphagia secondary to a metastatic tumor in the esophagus.

Cytofluorometric analysis for estrogen receptors using fluorescent estrogen probes

Estrogen receptor (ER) analysis of breast cancer tissue has been shown to be very useful in predicting which patients will respond to hormone therapy and have a better prognosis. The ER assay is, however, tedious and time consuming. Measurement of ER by flow cytometry would be rapid and based on either an average fluorescence-E2 probe intensity per cell or the percentage of the ER+ cells per cell suspension. Analysis of E2 modified structures for relative binding affinity to the ER determined by competition studies and for fluorescence uptake into cell suspensions determined by flow cytometry was performed. Lack of high affinity to the ER and purity of the compound were major problems for the fluorescein-labeled estrogen probes. Base hydrolysis of the ester linkage in fluorescein-E2 compounds demonstrated by HPLC very little estradiol derivative in the parent compounds compared to total components present. A second type of fluoresceinated estrogen which has a peptide bond between the steroid and the chromophore was also tested. It was less contaminated but was unable to get into the cell and showed no binding activity to the ER. A pure plant fluorescent estrogen, coumestrol, has Ka of 6 X 10(8) M-1 for the ER and is a single component as determined by HPLC. Specific fluorescent uptake of coumestrol was performed on ER+ and ER- viable cell suspensions. When these coumestrol-cell suspensions were excited at 350-360 nm and the blue emission was measured using flow cytometry, the result was a fluorescence uptake that was not highly displaceable by excess nonfluorescence E2 probes.(ABSTRACT TRUNCATED AT 250 WORDS)

Preparation and stability of sixteen murine tissues and organs for flow cytometric cell cycle analysis

Three different technical protocols were used to prepare samples for flow cytometric (FCM) analysis. Each protocol developed worked best for only certain organs. Protocol I involved mincing small pieces of fresh tissue in the propidium iodide (PI) staining solution and filtering through packed glass wool. The organs that were prepared by protocol I were: submandibular gland, urinary bladder, liver, thymus, bone marrow, spleen, lung, kidney and testis. Protocol II involved exposure of the organ to 0.5% acetic acid for 48 h prior to mincing in the PI. The organs that were prepared by protocol II were: uterus, rectum, colon, ileum, and heart. Protocol III utilized an exposure to 0.5% acetic acid, pepsinization, and then staining with PI. The tissues that were prepared by protocol III were the epithelium of the anterior surface of the cornea and the epithelium of the surface of the tongue. A total of 16 different organs and tissues were successfully prepared. For each organ, averaged DNA histograms were analyzed by nonparametric and parametric programs and the results (phase fractions) are presented in tabular form. Several of the organs used came from animals exposed to 1.0 mg/kg vincristine (VC) for 5-6 h to test the capability of the different protocols to detect the enlargement of the G2 + M compartment by the accumulation of VC-arrested mitotic figures. The stability of the many different sample preparations was tested by comparing averaged DNA histograms obtained on the day of sample preparation to averaged DNA histograms of the same set of samples after storage at 4 degrees C, with or without fixation in 10% phosphate-buffered formalin, for days to weeks. After staining with propidium iodide, fixation of the sample with a final concentration of 2-3% phosphate-buffered formalin, was the procedure adopted to assure sample stability. The demonstration of sample stability permits sample preparation to occur at one site followed by transport of the samples to the FCM laboratory at another geographical location. The major findings of this work were a) technical protocols were developed which resulted in acceptable nuclear suspensions for FCM from 16 different murine organs or tissues, b) the stability of these samples can be assured by fixing the PI stained nuclear suspension with formalin, and c) each different protocol was capable of detecting and preserving at least some of the mitotic figures arrested and collected by vincristine.

Cytologically malignant squamous-cell carcinoma arising in a verrucous carcinoma of the penis

A case of verrucous carcinoma with a focus of cytologically malignant squamous-cell carcinoma is presented. This usually occurs following radiation therapy of the verrucous carcinoma, but may rarely occur de novo, as in this case. The potential usefulness of fine-needle aspiration in detecting focal anaplasia in verrucous carcinoma is discussed. This technique may be especially useful if the lesion is to be destroyed cryosurgically.

Long-term storage of samples for flow cytometric DNA analysis

A simple procedure for long-term storage of cells for flow cytometric DNA analysis was developed and tested. The cells were stored as single cells or fine-needle aspirates suspended in a citrate buffer with dimethylsulfoxide (DMSO), or as small blocks of tissue from solid tumors. The cells were stored for up to one year by freezing at -80 degrees C. Statistical analysis of the results showed no change in the fractions of cells in the cell cycle phases as determined by deconvolution of the DNA-histograms. It was found that in addition to the intrinsic sample variation from the parameter estimation by deconvolution, there was significant intraday and interday variation. Hence the most accurate results are obtained if different aliquots of a sample are measured on different days rather than on the same day. Use of the storage method thus has the potential of increasing the accuracy of the analysis. The storage method makes sample collection independent of immediate subsequent analysis. This has enabled us to perform large internally controlled experiments, involving more samples than can be analyzed in one day, to examine tumor samples from different hospitals and to utilize fully the capacity of our flow cytometer. The method was a prerequisite for developing an accurate standardization procedure for DNA content determination.

Polyploid nuclei in human artery wall smooth muscle cells

Although polyploid nuclei have long been known to be present in many adult human tissues, the ploidy of smooth muscle cells in human artery wall has never been determined. We measured DNA content in individual smooth muscle cell nuclei of artery wall specimens by two means: Feulgen microdensitometry and flow microfluorimetry. A significant percentage of nuclei were polyploid; most of these were tetraploid, although higher levels were also found. The frequency of polyploidy varied with age from less than 1% at birth to a mean of 7% in adult aortic, carotid, and iliac vessels. Atherosclerotic plaques had a lower tetraploid content than the underlying media, whereas normal intima was similar to the corresponding media. The increase in frequency of hyperploid smooth muscle cell nuclei correlates with the normal growth, development, and aging of human artery wall. We suggest that the regular existence of a subset of polyploid smooth muscle cells may indicate an important functional role for this phenotype.

RNA and DNA content of isolated cell nuclei measured by multiparameter flow cytometry

Nuclei were isolated from various cell types including Chinese hamster ovary (CHO) and L1210 leukemia cell lines, primary cultures of fibroblasts, nonstimulated and stimulated human lymphocytes and mouse liver cells, by using different isolation techniques. The isolated nuclei were subsequently stained with acridine orange (AO) and their fluorescence was measured by flow cytometry. Various procedures designed to stain DNA versus RNA differentially with AO were tested, and the staining of isolated nuclei was compared with that of whole cells. Control incubations with RNase and DNase were performed to estimate in whole cells and in nuclei the contribution of DNA and RNA to the fluorescence intensity at the respective wavelength bands of maximum emission for DNA (F530) and RNA (F greater than 600). Depending on the cell type, 10-20% of total cell RNase-sensitive F greater than 600 is localized in the nuclei. The RNase-resistant portion of F greater than 600 of isolated nuclei represents the stainability of DNA. Suppression of cell proliferation in subconfluent cultures results in a decrease in both whole cell and in nuclear RNA content. Nonstimulated lymphocyte nuclei have considerably lower RNA content than nuclei from lymphocytes stimulated by pokeweed mitogen. Two subpopulations of nuclei having the same (2C) DNA content but differing in RNA content, are present in mouse liver; the cells entering S phase originate from the high RNA population.

Evidence that a critical threshold of DNA polymerase-alpha activity may be required for the initiation of DNA synthesis in mammalian cell heterokaryons

The specific activity of DNA polymerase (90% alpha) was determined in nine "neoplastoid" cell lines (Martin and Sprague, 1973) and in three different strains of HDF (human diploid fibroblast-like cells), all examined in logarithmic phases of growth. This was compared to the ability of each cell type to "rescue" (reinitiate DNA synthesis in) senescent HDF cells subsequent to polyethylene glycol-mediated cell fusions. A sharp "threshold" value of DNA polymerase activity was observed below which reinitiation of DNA synthesis in heterokaryons with senescent HDF does not occur. This threshold was especially obvious when the specific activity of DNA polymerase (p moles dTTP incorporated per mg protein or per cell) was divided by the percent of S-phase cells present in each culture as determined by flow microfluorometry. Our results indicate that the specific activity of DNA polymerase-alpha (or some other factor tightly coregulated with it) in "recessive" cell types (those unable to rescue senescent cells) is only about two times this theoretical "threshold" value, and that fusion of recessive cell types to senescent HDF cells reduces the specific activity in the heterokaryon to below this minimum, thus preventing the cells from entering S phase.

Modulation of glucocorticoid hormone receptor levels in chicken lymphoid tissue following treatment with androgens in vivo

Lymphatic tissues are highly sensitive to androgens and androgens are thought to contribute to sex differences in the immune response. In this study we have examined the effects of androgens on cytosolic glucocorticoid receptor levels in lymphoid tissues. The immature chick was chosen for our experimental model because it allows the separate evaluation of the bursa of Fabricius (primarily B-cells) compared to the thymus (primary T-cells). Treatment with dihydrotestosterone (a potent androgen in chicks) for 3-12 days in vivo reduced the cytosolic glucocorticoid (triamcinolone acetonide-[3H]) receptors in bursa tissue to approximately 42% of control levels after 5 days and less than or equal to 5% of control levels after 7 days of treatment. The chick thymus tissues were still approximately 92% of control triamcinolone acetonide receptor levels after 5 days of androgen treatments. However the thymus levels had dropped to less than or equal to 5% of control values after 12 treatment days. Thus a difference in the rate of decrease in the bursa of Fabricius compared to the thymus was indicated. The blastogenesis index (BI), a measurement of the percentage of cells progressing through the cell cycle, was figured using fluorescent DNA staining with diamidino phenylindole followed by flow cytometry analysis. After 3, 5, or 7 days of androgen treatment, the bursa of Fabricius from dihydrotestosterone treated chicks (2 mg/day/chick) had a mean BI = 11.17 (+/- 3.07 SD) which was significantly lower than the bursa of Fabricius from control chicks which showed a mean BI = 27.33 (+/- 3.42 SD). The thymus from dihydrotestosterone treated chicks had a mean BI = 19.57 (+/- 2.19 SD) which was slightly but not significantly higher than the control thymus CI = 17.38 (+/- 0.89 SD). In summary, androgen treatment in vivo induced a decrease in the cytosolic glucocorticoid hormone receptor levels in both the chick thymus and bursa of Fabricius tissues while decreasing the blastogenesis index in the bursa cells but not in the thymus cells.

Flow cytometric measurement of ploidy and proliferative activity of carcinomas of the oropharyngeal mucosa

The most important indicator of ploidy and cell cycle stage in ortho- and pathologic tissues is the nuclear DNA content. To study this parameter of malignancy in squamous carcinomas of the oral, pharyngeal, or laryngeal mucosa we analyzed DNA histograms by aid of flow cytophotometry after using pepsin digestion of tumor specimens for cell dispersal and fluorochromation with combined ethidium bromide and mithramycin. In 30 of 36 tumor tissue specimens aneuploid states of nuclear DNA content (83%) were recognized, in some cases only by comparing tumor cells with admixed diploid human reference cells. All but two tumors (with hypodiploid DNA pattern) exhibited hyperdiploid stem line abnormalities, one specimen even exhibited them with triclonal DNA distribution pattern. The degree of ploidy (DNA index), defined as the ratio of peak modal channel number for the G1/0 proportion of tumor cells to that of normal cells, ranged from 0.59 to 3.24 (mean 1.58). Cell cycle analysis of untreated squamous carcinomas, calculated by the relative DNA distribution pattern in histograms, also offered a considerable variation in proliferative activity.

Smooth muscle cell hypertrophy versus hyperplasia in hypertension

Arteries of hypertensive animals have a greater mass of smooth muscle than those of normotensive controls. We examined the contribution of smooth muscle cell hypertrophy and hyperplasia to this increase in mass. Cell size measurements obtained by (i) image analysis of enzyme-dispersed cells, (ii) morphometric evaluation of tissue sections, and (iii) biochemical measures of protein/cell and actin/cell ratios on isolated cells showed that average cell size was greater in spontaneously hypertensive rats than in normotensive Wistar-Kyoto and Sprague-Dawley controls. Average DNA/cell ratios were also increased in spontaneously hypertensive rats while protein/DNA ratios were not different. Analysis of nuclear DNA content of individual cells by flow microfluorimetry and Feulgen-DNA microdensitometry measurements showed that greater than 20% of spontaneously hypertensive rats cells were polyploid while less than 10% of control cells were polyploid. Estimates of cell number per centimeter of aortic length, based on ploidy and DNA content, show no difference between control and hypertensive rats. Thus, smooth muscle hypertrophy alone accounts for the increased mass of smooth muscle in aortas of spontaneously hypertensive rats. Furthermore, this cellular hypertrophy is accompanied by a change in nuclear ploidy. This nuclear response in hypertension may represent a fixed change related to the establishment of a chronic hypertensive state.

An immunofluorescence method for monitoring DNA synthesis by flow cytometry

An immunofluorescence method for monitoring DNA synthesis in single cells has been developed for flow cytometry. With antiserum which is specific for 5-bromodeoxyuridine (BrdUrd) and a second fluorescent label, BrdUrd-incorporation pulses of 30 min are detectable. The fluorescence intensity of the incorporated BrdUrd, as determined by immunofluorescence, is related to the amount of BrdUrd incorporated, as shown by isotopic methods and cell sorting. Thus, the technique may be applicable to determining rates of replication per cell. Multiple samples of as few as 1 X 10(5) cells can be fixed, hydrolyzed and treated with the anti-BrdUrd antiserum. Nuclear-bound IgG is localized by fluorescein-labeled avidin-D. Since the technique uses whole cells, other parameters such as light scatter and DNA content can be simultaneously monitored so that cohorts of "labeled" cells can be followed through the cell cycle.