Spectrofluorometric method for measuring tobacco smoke particulate matter on cigarette filters and Cambridge pads

Almost all cigarettes sold have a filter (United States, >98%; worldwide, >95%). In the last 25 years cigarette manufacturers have introduced diverse filters designed to reduce components in tobacco smoke. Today, there exists a need to establish assays to assess the efficacy of cigarette filters to retain total particulate matter (TPM), particularly unique filters of cigarettes that are being marketed as potential reduced exposure products (PREPs). We report the results of studies that were undertaken to test the hypothesis that a technique could be established for dissolving cigarette filters, and that the TPM in the fluid could be quantified by spectrofluorometry. Described here are procedures for assaying TPM on both Cambridge filter pads (glass fibres) of smoking machines and on cigarette filters (cellulose acetate fibres). The principle of the assays is based upon the observation that there exists a direct correlation between the amount of tobacco product emission TPM and fluorescence. In the absence of a tobacco tar or TPM standard, the fluorescent dye acridine orange was confirmed as a useful surrogate. Filters assayed included those of Kentucky reference cigarettes 2R4F and popular US brand cigarettes. The proposed assays are inexpensive, expedient, reproducible and amendable for large-scale studies.

Tobacco flakes on cigarette filters grow bacteria: a potential health risk to the smoker?

Bacterial growth from a single flake of tobacco was documented for cigarettes that had been purchased recently from local vendors and from cigarettes that had been stored for more than six years in a warehouse. In a novel tobacco flake assay, a pack of cigarettes was opened within the sterile environment of a laminar flow hood. A single flake of tobacco was collected randomly and aseptically from the middle of the cigarette column and placed onto the surface of a blood agar plate. The test cigarettes included eight different popular US brands, and these were from three different tobacco companies. After 24 hours of incubation at 37 degrees C, the plates showed bacterial growth for tobacco from all brands of cigarettes. Further, more than 90% of the individual tobacco flakes of a given brand grew bacteria. Likewise, bacteria grew from microparticulate tobacco that had been sieved from cigarettes. Tobacco flakes were observed lying loosely on the cut surface of the filter of cigarettes in newly opened packs, and bacteria grew from cigarette filters that had been touched to the surface of a blood agar plate. In conclusion, the results of these studies predict that diverse microbes and microbial toxins are carried by tobacco microparticulates that are released from the cigarette during smoking, and carried into mainstream smoke that is sucked deep into the lung.

Subcellular localization patterns and their relationship to photodynamic activity of pyropheophorbide-a derivatives

To determine if subcellular localization is important to photodynamic therapy (PDT) efficacy, an in vitro fluorescence microscopy study was conducted with a congeneric series of pyropheophorbide-a derivatives in human pharyngeal squamous cell carcinoma (FaDu) cells and murine radiation-induced fibrosarcoma (RIF) mutant cells. In the FaDu cells the octyl, decyl and dodecyl ether derivatives localized to the lysosomes at extracellular concentrations less than needed to produce a 50% cell kill (LD50). At extracellular concentrations equal or greater than the LD50 the compounds localized mainly to mitochondria. The propyl, pentyl, hexyl and heptyl ether derivatives localized mainly to the mitochondria at all concentrations studied. This suggested that mitochondria are a sensitive PDT target for these derivatives. Similar experiments were performed with two Photofrin-PDT resistant RIF cell lines, one of which was found to be resistant to hexyl ether derivative (C6) mediated-PDT and the other sensitive to C6-PDT relative to the parent line. At extracellular concentrations of C6 below the LD50 of each cell line, the mutants exhibited lysosomal localization. At concentrations above these values the patterns shifted to a mainly mitochondrial pattern. In these cell lines mitochondrial localization also correlated with PDT sensitivity. Localization to mitochondria or lysosomes appeared to be affected by the aggregation state of the congeners, all of which are highly aggregated in aqueous medium. Monomers apparently were the active fraction of these compounds because equalizing the extracellular monomer concentrations produced equivalent intracellular concentrations, photoxicity and localization patterns. Compounds that were mainly aggregates localized to the lysosomes where they were rendered less active. Mitochondria appear to be a sensitive target for pyropheophorbide-a-mediated photodamage, and the degree of aggregation seems to be a determinant of the localization site.