Percentage Of S-phase Fraction Research Articles

Effect of isothermal microwave exposure on the cell cycle

In cell biology, it has been known that microwave (MW) has non-thermal effect on cell cycle or cell proliferation. Recently, the next generation microwave heating apparatus (NGMW), which uses semiconductor with digital technology, has been developed. It is much easier to control power of MW, compared to conventional MW. We used this machine to examine the non-thermal effect on cell cycle. When HL-60 human leukemic cells were exposed to 20 or 40 Watts of MW at 37 or 42oC for 30 minutes, percentage of S-phase fraction in DNA histogram, analyzed by flow cytometry, increased dramatically (p = 0.026). When the same experiments were done using Propidium iodide (PI) and MIB-1 double staining, cycling cells increased significantly (p = 0.005). It is suggested that MW has non-thermal effect on cell cycle.

Flow cytometric cell cycle analysis of two subpopulations of porcine granulosa cells.

Two types of granulosa cells from 120 individual follicles (forty follicles in particular stages of development) were analysed by DNA flow cytometry to determine the percentage of cells with degraded DNA (apoptosis) and the cell cycle analysis. The distribution of cells in the cell cycle (G1, S, G2/M) was studied to show relation to location within a follicle and follicular development. Isolated granulosa cells were scraped from the vesicle walls with rounded-tip ophthalmological tweezers and separated into weakly-associated (AGc) and tightly-bound (MGc) according to Ford (1991) and Duda (1997). Granulosa cells after fixation in 70% ethanol and staining with propidium iodide (PI) were analysed. At least 20,000 events were collected in each specimen. The S-phase fraction (SPF) and apoptosis were calculated using the ModFit LT programme for the cell cycle analysis (Verity Software House Inc., USA). In AGc a population with degraded DNA was found, containing less fluorescence than the G1/G0 peak as shown in the DNA histograms. The percentage of apoptotic AGc ranged from 39.29 in small, to 58.9 in medium and was significantly higher than in large follicles (26.13%; p < 0.05). The percentage of apoptotic MGc was significantly lower than in the AGc (p < 0.05) and was equal to 3.78 in small, 0.10 in medium and 0.08% in large follicles. There are no significant statistical differences between the mean percentage of SPF in MGc of small and medium follicles (4.94, 7.25%). However, SPF was significantly lower in large follicles (1.31%). The number of SPF in AGc decreased during follicular development (35.92, 26.98, and 19.62%). Our data indicate lack of apoptotic cell death in MGc which seem to be more differentiated, and lose their mitotic potential. In AGc however, which are undifferentiated and undergo numerous mitosis, apoptosis was observed.

Relationship between interleukin-1-alpha concentration in tumors and cell growth in gastric cancer, determined using flow cytometry.

BACKGROUND: Interleukin-1-alpha (IL-1alpha) produced by tumor cells stimulates the proliferation or the growth of several cancer cell lines. The aim of this study was to clarify the relationship between growth activity evaluated by DNA analysis and the concentration of tumor-derived IL-1alpha in gastric cancers in clinical cases.METHODS: We measured the concentration of IL-1alpha in homogenized tumor samples obtained from 49 patients with gastric cancer, using an enzyme-linked immunosorbent assay, and we analyzed the cellular DNA content of paraffin-embedded tumor sections using flow cytometry.RESULTS: Both the IL-1alpha concentration and the percentage of S-phase fraction were significantly correlated with liver metastasis, histologic type, pattern of tumor infiltration, quantity of stroma, and venous invasion. A good correlation was found between IL-1alpha concentration in tumors and the percentage of S-phase fraction ( R = 0.604, P < 0.0001).CONCLUSION: IL-1alpha may be related to the stimulation of cell growth of gastric cancer in clinical cases.

Clinical application of flow cytometry for DNA analysis of solid tumors.

Recent developments of flow cytometry (FCM) technology which make multiple correlative biological measurements on normal and neoplastic cells is affecting areas of diagnostic pathology as well as research fields, and a general understanding of FCM techniques is essential for pathologists. Today, FCM DNA measurements of tumors also becomes routine in the clinical and/or pathological laboratory for aid in cancer diagnosis and cancer treatment. It can also contribute to diagnosis of tumors as a supplemental method to conventional histopathology, and DNA ploidy and the percentage of S-phase fraction are considered as complementary prognostic parameters independent of the stage of disease. This article reviews clinical applications of flow cytometry focusing on the DNA measurements of solid tumors, and related practical issues, such as the methodology for nuclear DNA measurement, interpretation of DNA histograms and the relationship of DNA ploidy and S-phase fraction to clinical and pathological features of human solid tumors.