Exposure data for cosmetic products: facial cleanser, hair conditioner, and eye shadow.

Reliable exposure information for cosmetic and other personal care products and ingredients is needed in order to conduct safety assessments. Essential information includes both the amount of product applied, and the frequency of use. To obtain current data, a study to assess consumer use practices was undertaken. Three widely used types of cosmetic products - facial cleanser, hair conditioner, and eye shadow - were included in the study. Three hundred and sixty women, ages 18-69 years, who regularly use the products of interest, were recruited nationwide within the US. Subjects were provided with a new container of the brand of product they normally use and kept diaries and recorded detailed daily usage information over a two week period. Products were weighed at the start and completion of the study in order to determine the total amount of product used. Statistical analyses of the data were conducted to derive summary distributions of use patterns. The mean and median usage per application, respectively, for the three product types were: facial cleanser, 2.57 g and 2.11 g; hair conditioner, 13.13 g and 10.21 g; and eye shadow, 0.03 g and 0.009 g. The mean and median usage per day for the three product types was: facial cleanser, 4.06 g and 3.25 g; hair conditioner, 13.77 g and 10.62 g; and eye shadow, 0.04 g and 0.010 g. The mean number of applications per day for facial cleanser, hair conditioner, and eye shadow was 1.6, 1.1, and 1.2, respectively. This study provides an estimate of current exposure information for commonly used products which will be useful for risk assessment purposes.

Mutagens and modulator of mutagenesis in fried ground beef.

It is now well documented that bacterial mutagens form in proteinaceous foods during cooking at moderate temperatures. Three heterocyclic amine mutagens have been identified by Sugimura and coworkers in fish and beef cooked under moderate heating conditions (T. Sugimura and S. Sato, Cancer Res. (Suppl.), 43: 2415s-2421s, 1983). The distribution of these known mutagens in commercial bacteriological-medium grade and food-grade beef extract, and in fried ground beef, is discussed. Of the known mutagens, we have been able to confirm only that 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline is present in fried ground beef. Deficiencies in currently used mutagen extraction procedures are addressed. It is likely that there are many mutagens in fried ground beef that are yet to be identified. Fried ground beef (and raw beef) also contains an activity which modulates bacterial mutagenesis apparently by interacting with rat liver microsomes which are added to metabolically activate promutagens. The modulator activity has been partially purified and either inhibits, enhances, or has no effect on promutagen activation depending on the promutagen under study and the pretreatment of the rat from which the microsomal fraction was obtained.

Characterization of human uroepithelial cells immortalized in vitro by simian virus 40.

Normal human uroepithelial cells (HUC) were transformed with simian virus 40 (SV40) in vitro. SV40-transformed HUC (SV-HUC) were selected by their ability to survive senescence which normally occurs in HUC between passages 4 and 6. At passage 6, 100% of SV-HUC stained positive for SV40 T-antigen. The epithelial nature of SV-HUC was confirmed by positive staining for human cytoplasmic keratins in all cells. SV-HUC have altered growth characteristics compared to HUC including the capacity to grow on plastic, independent of a collagen-gel substrate; loss of the dependence on medium supplements for optimal growth, loss of the dependence on feeder cells for growth at clonal density, and an apparently unlimited lifespan in culture (greater than 2 years). Although SV-HUC have an increased percentage of viable cells and increased saturation density compared to HUC, the generation time of SV-HUC during log phase is similar to that of HUC. Cultures of SV-HUC are epithelial in appearance and show some morphological heterogeneity in cell size and shape. At the ultrastructural level, SV-HUC have numerous alterations such as, irregularly shaped nuclei and nucleoli, pleomorphic microvilli, and the lack of a glycocalyx on the cell surface. In addition, SV-HUC does not stratify in culture, suggesting an inability to differentiate. Unlike HUC, SV-HUC are capable of growth in soft agarose, a property which increased with serial passage. Yet, through at least P50, SV-HUC remained nontumorigenic as determined by the inability to form tumors in athymic nude mice. This cell line of human epithelial origin may be suitable for studying the conversion of cells to tumorigenicity by subsequent treatment with another oncogenic agent.

Percutaneous penetration of diethanolamine through human skin in vitro: application from cosmetic vehicles.

Concern has been raised over the safety of diethanolamine (DEA) which may be present as a minor component of alkanolamide ingredients of cosmetic formulations. Skin penetration data were therefore generated for a range of typical formulations under in-use conditions. Seven rinse-off formulations (A-E, G and H), a leave-on emulsion (F), representing prototype cosmetic formulations and containing representative levels of DEA were prepared. Target levels of DEA were attained by inclusion of DEA as either (14)C-DEA or a combination of (14)C-DEA and unlabeled DEA. Skin permeation and distribution were evaluated using human skin in vitro, static diffusion cells and phosphate buffered saline (pH 7.4) as the receptor phase. At least 12 replicate epidermal membranes were prepared from a minimum of four donors for each test group. Receptor phase samples were taken at appropriate time intervals. At the end of the test period, radioactivity remaining on the skin surface and on the diffusion cell donor cap was determined before the skin samples were tape-stripped. The remaining tissue was solubilized and radioactivity determined. Permeation was very low from all vehicles applied under in-use conditions (range 1-48 ng/cm(2) over 24 h). Comparison was also made between permeation and distribution of DEA from an infinite dose of a simple aqueous solution and the leave-on formulation (F) through paired samples of fresh and frozen full thickness skin from the same donors. When applied as an infinite dose in aqueous solution DEA permeation at 24 h was greater through frozen than through fresh skin. From the leave-on formulation, permeation was similar and very low for both fresh and frozen skin. Recovery of DEA after application of the aqueous solution to fresh human skin and subsequent aqueous and organic extraction of the epidermal and dermal tissue indicated that the majority (>98%) of DEA was in the aqueous extract, suggesting that DEA was in the free state and not associated with the lipid fraction. These data provide a basis for the estimation of the potential systemic exposure and safety margins for DEA in representative cosmetic formulations.

Exposure data for cosmetic products: lipstick, body lotion, and face cream.

Accurate exposure information for cosmetic products and ingredients is needed in order to conduct safety assessments. Essential information includes both the amount of cosmetic product applied, and the frequency of use. To obtain current data, a study to assess consumer use practices was undertaken. The study included three widely used cosmetic product types: lipstick, body lotion, and face cream. Three hundred and sixty women, ages 19-65 years, who regularly use the products of interest, were recruited at ten different geographical locations within the US. The number of recruits was chosen to ensure a minimum of 300 completes per product type. Subjects were provided with prototype test products, and kept diaries and recorded detailed daily usage information over a two week period. Products were weighed at the start and completion of the study in order to determine the total amount of product used. Statistical analysis of the data was conducted to derive summary distribution of use patterns. The mean and median usage per application, respectively, for the three products was: face cream, 1.22 g and 0.84 g; lipstick, 10 mg and 5 mg; and body lotion, 4.42 g and 3.45 g. The mean and median usage per day for the three products was: face cream, 2.05 g and 1.53 g; lipstick, 24 mg and 13 mg; and body lotion, 8.70 g and 7.63 g. The mean number of applications per day for face cream and lipstick was 1.77 and 2.35, respectively. For body lotion, the mean number of applications per day was dependent on body area, and was 2.12, 1.52, 1.11, 0.95, 0.43, 0.26, and 0.40 for hands, arms, legs, feet, neck and throat, back, and other body areas, respectively. The effect of product preference on use practices was also investigated. This study provides current cosmetic exposure information for commonly used products which will be useful for risk assessment purposes.

Promutagen activation by freshly isolated and cryopreserved rat hepatocytes.

The metabolic activation of promutagens by freshly isolated and cryopreserved rat hepatocytes was compared using the Chinese hamster ovary/hypoxanthine-guanine phosphoribosyltransferase assay (CHO/HGPRT). Cryopreserved rat hepatocytes were equivalent to freshly isolated hepatocytes in their ability to metabolize dimethylbenz(a)anthracene (DMBA) and dimethylnitrosamine (DMN) to active mutagens. Similar dose-response curves were observed using either freshly isolated or cryopreserved hepatocytes as activating systems after treatment with DMBA (0.1-1 micrograms/ml) and DMN (0.075-0.6 mg/ml). Our results suggest that cryopreserved hepatocytes are similar to freshly isolated hepatocytes as an experimental system for studies on promutagen activation.

Clonal growth of normal human uroepithelial cells.

We report the development of culture conditions which routinely support clonal growth of normal human uroepithelial cells (HUC). Secondary cultures seeded at clonal densities and grown under conditions described herein have a colony-forming efficiency (CFE) and colony size that will be useful for in vitro experiments. Primary cultures were dispersed to single cells and seeded in a supplemented Ham's F12 medium containing 1% fetal bovine serum together with 3 X 10(5) lethally irradiated Swiss 3T3 feeder cells on plastic substrates preequilibrated with F12 medium containing 5 or 10% serum. Using these conditions, the average CFE was 16.1 +/- 2.5%. A cloning efficiency of 4.9 +/- 1.5% was obtained under the same conditions in serum-free F12+ when supplemented with a mixture of trace elements or 0.1 mM ethanolamine. The epithelial nature of the cloned cells was confirmed by morphology and by positive immunofluorescent staining for human epithelial keratin proteins. To make this system useful for mutagenesis experiments, a clone of Swiss 3T3 feeder cells resistant to 5 micrograms/ml 6-thioguanine (6TG) was derived from the parental cell line. This 6-TG-resistant Swiss 3T3 clone supports HUC clonal growth with a CFE of 17.9 +/- 2.0% CFE. We also report clonal growth of HUC without feeder cells using supplemented MCDB 170 medium containing 70 micrograms/ml bovine pituitary extract. The average cloning efficiency using these conditions was 5.7 +/- 1.7%.

Effect of glutathione levels, sulfate levels, and metabolic inhibitors on covalent binding of 2-amino-3-methylimidazo[4,5-f]quinoline and 2-acetylaminofluorene to cell macromolecules in primary monolayer cultures of adult rat hepatocytes.

The covalent binding of radiolabeled 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-acetylaminofluorene (AAF) to cell macromolecules was studied using primary monolayer cultures of adult rat hepatocytes. A time course for covalent binding was determined, and revealed similar levels of binding for both chemicals. Inhibition of glutathione synthesis by L-buthionine sulfoximine (1 mM) enhanced binding of both AAF and IQ with a greater increase observed for IQ. Addition of excess glutathione (10 mM) to the medium resulted in a slight decrease in IQ but not AAF binding. Addition of the P-450 inhibitor, 2-[2,4-dichloro-6-phenyl)-phenoxy]ethylamine (DPEA, 0.1 mM), resulted in almost total (94%) inhibition of IQ binding, with a lesser effect (42%) on AAF. Methimazole (1 mM), a competitive substrate of the flavin-containing monooxygenase, had no effect on the binding of either compound. Pentachlorophenol, an inhibitor of sulfate conjugation, decreased AAF binding substantially but produced a much smaller decrease in IQ binding. Addition of excess sulfate did not change the binding levels of either IQ or AAF. Cell density had little effect on IQ or AAF binding levels.

Quantitative assessments of the cytotoxicity of bladder carcinogens towards cultured normal human uroepithelial cells.

Chemical carcinogens are known to exert cytotoxic effects on cells. The survival of cultured human uroepithelial cells (HUC) after exposure to several important classes of human and experimental animal bladder carcinogens has been quantitatively assessed in vitro using reduction in cell number and/or colony forming efficiency as the endpoint(s). Cells were treated with different carcinogens or various metabolites of a procarcinogen and the responses were analyzed with respect to the cell type used and to the donor source of the cells. The cytotoxic responses of HUC to the stable bladder procarcinogens tested [4-aminobiphenyl (ABP), 4-nitrobiphenyl, N-[4-(5-nitro-2-furyl)-2-thiazole]formamide and 2-amino-4-(5-nitro-2-furyl)thiazole] were dependent on both the concentration of chemical used and the duration of exposure. The survival of HUC after exposure to several metabolites of ABP differed. The N-hydroxylated derivatives of ABP (N-hydroxy-4-amino-biphenyl and N-hydroxy-4-acetylaminobiphenyl) were considerably more cytotoxic toward HUC than ABP or 4-acetylaminobiphenyl. The survival of HUC from different individuals after treatment with the direct acting carcinogen N-nitro-N-methylurea was very similar. In contrast, the survival of HUC from different donors varied considerably after treatment with the procarcinogen 3-methylcholanthrene which requires metabolic activation. However, significant heterogeneity in the survival of HUC from five donors after exposure to the human bladder procarcinogen ABP was not observed in this study. Cultures of normal human fibroblasts from four donors showed an unexpected heterogeneous response to the cytotoxic effects of ABP. These results demonstrate that many variables affect the cytotoxic response of normal cells to bladder carcinogens.

Optimization of cryopreservation procedures for rat and human hepatocytes.

1. Rat hepatocytes were cryopreserved using a number of procedures and the viability, attachment, and metabolic activity of the cryopreserved cells were compared to freshly isolated hepatocytes. Several cryopreservation agents (dimethylsulphoxide [DMSO], glycerol, polyvinylpyrrolidone [PVP], dextrans), and combinations of these agents, were examined. Other variables tested included the freezing rate, thawing rate, and the concentration of serum in the freezing medium. 2. Recovery of viable attached cells was optimal using DMSO at concentrations of 10% or higher, a slow stepwise cooling procedure, and a quick thaw. The concentration of serum in the freezing medium (0% to 90%) did not affect cryopreservation results. Using this procedure the recovery of viable hepatocytes was 70%. 3. Levels of hepatocyte ethoxycoumarin-O-deethylase (ECOD) activity did not change following cryopreservation. The rate of decline of ECOD activity with time in culture was similar in freshly isolated and cryopreserved hepatocytes. 4. Hepatocytes isolated from three human livers were cryopreserved and recovered with viabilities similar to those obtained with the rat. A preliminary experiment also showed no loss of metabolic activity in human hepatocytes following cryopreservation.

Growth kinetics and differentiation in vitro of normal human uroepithelial cells on collagen gel substrates in defined medium.

Conditions have been described for the selective growth, serial cultivation, and postconfluent morphological differentiation in vitro of normal adult human uroepithelial cells (HUC) on collagen gel substrates in a serum-free medium without the deliberate addition of undefined components and without a requirement for a polypeptide growth factor. The culture medium used (F12) was the standard Ham's F12 medium (0.3 mM calcium) supplemented with 1 microgram/ml hydrocortisone, 5 micrograms/ml transferrin, 10 micrograms/ml insulin, 0.1 mM nonessential amino acids, 2.0 mM L-glutamine, 2.7 mg/ml D-glucose, 10(-4) M ethanolamine or 10(-4) M phosphoethanolamine, and 5 X 10(-8) M selenium. HUC grown in F12 on Type I collagen gel substrates had a generation time of 33 hours and could be serially passed 3-5 times during log phase of growth (20-25 population doublings) before spontaneously senescing. Transmission electron microscopy showed that cultures of HUC grown entirely in serum-free F12 on collagen gel substrates morphologically differentiate postconfluence to resemble in some respects the stratified uroepithelium in vivo, although neither a basal lamina nor an asymmetric unit membrane develop. The addition of epidermal growth factor (EGF) to the F12 did not improve either the growth rate or the lifespan in vitro of HUC. In contrast, the addition of fetal bovine serum (FBS) to F12 was mitogenic to HUC in a dose-dependent manner in the concentration range 0.01-1.00% (4-400 micrograms/ml protein), but higher concentrations of FBS did not improve growth further. The generation time of HUC in 1% FBS-F12 decreased to 21 hours, and the potential population doublings in vitro increased to 31-36. Small amounts (140 micrograms/ml) of bovine pituitary extract (BPE) were similarly mitogenic to HUC in F12. Altering the calcium concentration in the standard Ham's F12 medium (0.3 mM), however, did not improve the growth of HUC in serum-containing or serum-free medium. Higher calcium concentrations (0.30-0.90 mM) were neither mitogenic nor inhibitory to HUC growth, but resulted in decreasing viability of HUC in growing cultures, suggesting an accelerating rate of cellular differentiation. In contrast HUC in low calcium, serum-free F12 (0.1 mM) failed to stratify and morphologically differentiate even in postconfluent cultures. This failure of HUC to differentiate in low calcium F12 medium did not confer a long-term growth advantage.(ABSTRACT TRUNCATED AT 400 WORDS)

Neoplastic transformation of SV40-immortalized human urinary tract epithelial cells by in vitro exposure to 3-methylcholanthrene.

Normal human urinary tract epithelial cells (HUC) were neoplastically transformed in vitro using a step-wise strategy. First, a partially transformed non-virus-producing cell line was obtained after infection of HUC with simian virus 40 (SV40). This cell line (SV-HUC-1) was demonstrated to be clonal in origin, as 100% of cells contained at least five of seven marker chromosomes. Marker chromosomes were formed by balanced translocations resulting in a 'pseudodiploid' cell line. SV-HUC-1 showed altered growth properties in vitro (e.g. anchorage independent growth) but failed to form tumors in athymic nude mice, even after 3 years in culture (80 passages). In the studies reported here, SV-HUC-1 at early passages (P15-P19) were exposed to 3-methylcholanthrene (MCA) in three separate experiments. After a six-week post-treatment period of cell culture, cells were inoculated s.c. into athymic nude mice. In all experiments, MCA-treated SV-HUC-1 formed carcinomas in mice usually with a latent period of 5-8 weeks. These carcinomas showed heterogeneity with respect to histopathologies and growth properties in the mice and karyotypes. All the tumors retained SV-HUC-1 chromosome markers, but each independent transformant was aneuploid and contained unique new marker chromosomes. Chromosomes usually altered in tumor cells included numbers 3, 5, 6, 9, 11 and 13. Mutations in the ras family of cellular proto-oncogenes resulting in altered mobility of the p21 protein product were not detected in six cell lines established from independently derived tumors. It is not yet known whether other cellular proto-oncogenes are activated in these tumorigenic transformants. Neither control SV-HUC-1 (which were not exposed to MCA), nor early passage HUC exposed to MCA formed tumors when inoculated into mice. Thus, the tumorigenic transformation of HUC resulted from the combined actions of SV40 and MCA.