The enzyme‐linked immunosorbant assay (ELISA) was modified to (1) characterize antibodies raised in rabbits against UV‐irradiated single‐stranded DNA (UVssDNA) complexed with methylated BSA and (2) directly detect pyrimidine dimers in irradiated DNA. The antisera specifically bound to UVssDNA, UVpoly(dT) and to a limited extent to UVdsDNA and UVpoly(dC) immobilized on protamine sulfate coated microliter wells. Fifty percent of the maximum antibody binding was observed at a 1‐5000 dilution against UVssDNA. Binding to ssDNA and poly(dT) was observed only at much higher concentrations of antibody (1:500 dilution), whereas no binding to double stranded DNA (dsDNA) was observed. The extent of binding of the antibody was dependent on the dose of UV radiation to DNA, as well as, to the concentration of antigen immobilized on the plate. Specific binding to DNA irradiated with 5.0 J/m2 was detected with as little as 10 ng of DNA. The sensitivity was further extended to less than 1 J/m2 by using higher concentrations (100 ng) of UVssDNA. The ability of various irradiated molecules, DNA, homopolymers and linkers to act as inhibitors of antibody binding establish that the antigenic determinants are mainly thymine homodimers with lower affinity for cytosine dimers. Potential usefulness of the antibodies to directly quantitate pyrimidine dimers in cells exposed to UV radiation was determined by indirect immunofluorescence. Flow cytometric analysis of immunostained human lymphocytes irradiated with 254 nm radiation indicated that greater than 50% of the population had significantly higher fluorescent intensity than unirradiated control cells.

Studies have shown that nonsteroidal antiinflammatory drugs (NSAIDs) reduce the risk of and mortality from a variety of cancers. Although cyclooxygenase (COX)-dependent and -independent pathways may be involved, the mechanisms responsible for these effects remain unknown. In our study, we found that piroxicam inhibited cell growth in premalignant and malignant, but not normal, human oral epithelial cell lines in a concentration-and time-dependent manner. After 6 days of exposure, the concentration that inhibited growth by 50% was 181 and 211 M for premalignant and malignant cells, respectively. Piroxicam did not induce apoptosis. The growth inhibitory effect was COX and PGE 2 independent. Adding PGE 2

OPT clearance may be enhanced by TXL when the two agents are used in combination in patients. The Pt-DNA adduct level in peripheral WBC was found to be a good indicator for oxaliplatin exposure in patients, and should be further exploited for potential tumor drug exposure.

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A method is described for the isolation of large numbers of viable disaggregated cells from human tissues. This method combined the mechanical action of a Stomacher Model 80 Lab Blender, 0.1 mg/ml trypsin or 0.5 mg/ml collagenase, and 0.1 mM [ethylene bis(oxyethylenenitrolo)]-tetraacetic acid (EGTA). Tissue (0.2 to 1.0 g) obtained from human fetal intestine, kidney, liver, lung, and skin were separately minced into approximately 1-mm3 pieces. The pieces were placed in a sterile bag containing 60 ml of calcium- magnesium-free phosphate buffered saline, the appropriate enzyme (0.1 mg/ml trypsin or 0.5 mg/ml collagenase) plus 0.1 mM EGTA, and 0.1% methylcellulose. The bag was then placed into the blender and mixed at a low speed for 3 to 20 min at room temperature. After a single cell suspension was observed by phase contrast microscopy, 10 ml of bovine calf serum was added to the cell suspension to inactivate the proteolytic enzymes. At this time 130 ml of cold Hanks' balanced salts solution containing 5% bovine calf serum was added and the entire cell suspension passed through a tissue sieve (100 mesh, 140 micron) and the cells collected by centrifugation. These cells were then resuspended into the appropriate culture medium. In comparison to other methods for establishment of cell cultures from human tissues, the method described requires shorter incubation times with relatively low concentrations of proteolytic enzymes, and yields two- to three-fold greater number of cells per tissue with 86 to 93% viability. Also, depending on the cell type, 50 to 75% of the isolated cells attached to the culture vessel within 24 h. Variation of the time and concentration of digestive enzymes can be used to select different cell types for culture.