Evaluation of metabolic reactivity in macrophages from mice with chronic sodium arsenite intake and experimental carcinogenesis.

 Arsenic is carcinogenic to human beings, and environmental exposure to arsenic is a public health issue that affects large populations around the world. Thus, studies are needed to determine the mode of action of arsenic and to prevent harmful effects that arise from arsenic intake. In particular, knowledge of the effects of arsenic exposure in individuals who are undergoing a carcinogenesis process is lacking.

Effect of Sodium Arsenite on Mouse Skin Carcinogenesis.

Arsenic is carcinogenic in human beings, and environmental exposure to arsenic is a public health issue that affects large populations worldwide. Thus, studies are needed to determine the mode of action of arsenic and prevent harmful effects arising from arsenic intake. The present study assessed the influence of sodium arsenite (As(3+)) on potentially carcinogenic processes that are either pre-existing or concomitant with chronic intake of water containing As(3+).

Phosphorylation and subcellular localization of p27Kip1 regulated by hydrogen peroxide modulation in cancer cells.

The Cyclin-dependent kinase inhibitor 1B (p27Kip1) is a key protein in the decision between proliferation and cell cycle exit. Quiescent cells show nuclear p27Kip1, but this protein is exported to the cytoplasm in response to proliferating signals. We recently reported that catalase treatment increases the levels of p27Kip1 in vitro and in vivo in a murine model.

H2O2 scavenging inhibits G1/S transition by increasing nuclear levels of p27KIP1.

The aim of the present study was to evaluate cell cycle regulation by scavenging H(2)O(2) in tumor cells. A significant arrest in the G1 phase of the cell cycle was demonstrated in CH72-T4 carcinoma cells exposed to catalase, associated with a decrease in cyclin D1 and an increase in the CDK inhibitory protein p27(KIP1). Moreover, we found a differential intracellular distribution of p27(KIP1), which remained in the nucleus after catalase treatment.

Oxidative metabolism of lung macrophages exposed to sodium arsenite.

Arsenic pollution has become increasingly severe. It occurs as the result of geological processes and different human activities. Arsenic toxicity at the respiratory level occurs mainly by inhalation of products of coal combustion.

Kinetics of MTT-formazan exocytosis in phagocytic and non-phagocytic cells.

MTT is taken up by cells by endocytosis and reduced to formazan in the endosomal/lysosomal compartment. Formazan is deposited intracellularly as blue granules and is later exocytosed as needle-like formazan crystals. The present study involves an analysis of the pattern of exocytosis of MTT in different cell types showing clearcut differences in the response that can be associated to their ability to phagocytose.

Cell-based quantitative evaluation of the MTT assay.

Objective: To analyze the bioreduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) on a per cell basis and evaluate its modulation as a function of different stages of cell metabolism.

Study Design: Following MTT bioreduction, total optical density (TOD), cell area and specific activity (TOD/area) of V79 cells and cultured macrophages were recorded for individual cells by means of digital image analysis. The effect of different serum (0-10% vol/vol) or genistein (0-100 microM) concentrations was used to modulate the MTT-specific activity response.