Absorption enhancement, structural changes in tight junctions and cytotoxicity caused by palmitoyl carnitine in Caco-2 and IEC-18 cells.

Palmitoyl carnitine chloride (PCC) has been shown to be an effective enhancer of intestinal transport of hydrophilic molecules. The exact mechanism by which the epithelial barrier function is decreased is not clear. In an attempt to elucidate the mechanism of action of PCC, we studied the relationship among absorption enhancement, cell viability and tight junction protein localization in the human colonic Caco-2 cell line and the rat small intestinal cell line IEC-18.

Detection of DNA adducts in basal and non-basal cells of the hamster trachea exposed to benzo(a)pyrene in organ culture.

DNA adducts were quantified in hamster tracheas exposed to benzo(a)pyrene (BP) in organ culture, in basal as well as in non-basal cells, by in situ detection with an adduct-specific rabbit antiserum (W2/01) and with a mouse monoclonal antibody against human cytokeratins 5 and 8 (RCK102) to identify hamster trachea basal cells. Recognition by W2/01 of the adduct of (+)-anti-7,8-dihydroxy-9,10-epoxide of BP (BP-diolepoxide; BPDE) to deoxyguanosine (dG) was checked on human white blood cells (WBCs) exposed to BP together with 3-methylcholanthrene (3MC)-induced rat-liver microsomes. By comparison with the adduct levels determined by 32P post-labeling, a lower detection limit of about 1 adduct per 10(6) nucleotides could be deduced.

Detection of benzo[a]pyrene-DNA adducts in cultured cells treated with benzo[a]pyrene diol-epoxide by quantitative immunofluorescence microscopy and 32P-postlabelling; immunofluorescence analysis of benzo[a]pyrene-DNA adducts in bronchial cells from smoking individuals.

Monoclonal antibodies were raised against the reaction product of benzo[a]pyrene diol-epoxide (BPDE) and deoxyguanosine-5'-monophosphate. The antibodies were used for detection of DNA adducts in situ in BPDE-treated cultured human fibroblasts by immunofluorescence microscopy. Analogue-digital conversion of the fluorescence signal and further image processing allowed measurement of the immunospecific fluorescence in the nuclei of these cells.