Safety evaluation of food contact paper and board using chemical tests and in vitro bioassays: role of known and unknown substances.

In vitro toxicological tests have been proposed as an approach to complement the chemical safety assessment of food contact materials, particularly those with a complex or unknown chemical composition such as paper and board. Among the concerns raised regarding the applicability of in vitro tests are the effects of interference of the extractables on the outcome of the cytotoxicity and genotoxicity tests applied and the role of known compounds present in chemically complex materials, such as paper and board, either as constituents or contaminants. To answer these questions, a series of experiments were performed to assess the role of natural substances (wood extracts, resin acids), some additives (diisopropylnaphthalene, phthalates, acrylamide, fluorescent whitening agents) and contaminants (2,4-diaminotoluene, benzo[a]pyrene) in the toxicological profile of paper and board. These substances were individually tested or used to spike actual paper and board extracts. The toxic concentrations of diisopropylnaphthalenes and phthalates were compared with those actually detected in paper and board extracts showing conspicuous toxicity. According to the results of the spiking experiments, the extracts did not affect the toxicity of tested chemicals nor was there any significant metabolic interference in the cases where two compounds were used in tests involving xenobiotic metabolism by the target cells. While the identified substances apparently have a role in the cytotoxicity of some of the project samples, their presence does not explain the total toxicological profile of the extracts. In conclusion, in vitro toxicological testing can have a role in the safety assessment of chemically complex materials in detecting potentially harmful activities not predictable by chemical analysis alone.

Test procedures for obtaining representative extracts suitable for reliable in vitro toxicity assessment of paper and board intended for food contact.

This paper describes the use of a suite of extraction procedures applicable to the assessment of the in vitro toxicity of paper/board samples intended for food-contact applications. The sample is extracted with ethanol, water, or exposed to modified polyphenylene oxide (Tenax) for fatty, non-fatty and dry food applications, respectively. The water extracts are directly suitable for safety assessment using in vitro bioassays. The ethanol extracts of the paper/board and of the exposed Tenax require pre-concentration to give acceptable sensitivity. This is because the in vitro bioassays can tolerate only a small percentage of added organic solvent before the solvent itself inhibits. The extraction procedures have been selected such that they mimic the foreseeable conditions of use with foods and that they are also fully compatible with the battery of in vitro biological assays for the safety assessment of the total migrate. The application of the extraction protocols is illustrated by the results for one of the many paper/board samples provided by the BIOSAFEPAPER project industrial platform members. The assessment indicated that this sample should not be considered as suitable for use with fatty foodstuffs but was suitable for dry and non-fatty foods. Information subsequently received from the manufacturer revealed that this was a non-food-grade product included in the project to test the capabilities of the bioassay procedures. The selection criteria for the test conditions and the suite of methods developed have been prepared in Comité Européen de Normalisation (CEN) format and is currently being progressed by CEN/TC172 as a European Standard.

The BIOSAFEPAPER project for in vitro toxicity assessments: preparation, detailed chemical characterisation and testing of extracts from paper and board samples.

Nineteen food contact papers and boards and one non-food contact board were extracted following test protocols developed within European Union funded project BIOSAFEPAPER. The extraction media were either hot or cold water, 95% ethanol or Tenax, according to the end use of the sample. The extractable dry matter content of the samples varied from 1200 to 11,800 mg/kg (0.8-35.5 mg/dm2). According to GC-MS the main substances extracted into water were pulp-derived natural products such as fatty acids, resin acids, natural wood sterols and alkanols. Substances extracted into ethanol particularly, were diisopropylnaphthalenes, alkanes and phthalic acid esters. The non-food contact board showed the greatest number and highest concentrations of GC-MS detectable compounds. The extracts were subjected to a battery of in vitro toxicity tests measuring both acute and sublethal cytotoxicity and genotoxic effects. None of the water or Tenax extracts was positive in cytotoxicity or genotoxicity assays. The ethanol extract of the non-food contact board gave a positive response in the genotoxicity assays, and all four ethanol extracts gave positive response(s) in the cytotoxicity assays to some extent. These responses could not be pinpointed to any specific compound, although there appeared a correlation between the total amount of extractables and toxicity.

Assessment of the genotoxicity of the rat carcinogen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) in rat liver epithelial cells in vitro.

3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a disinfection by-product in chlorinated drinking water, is a multisite carcinogen in rats. One main target organ is the liver. The mechanism of the tumorigenicity was evaluated by testing the genotoxicity of MX in rat liver epithelial cell line cells. In the studies, the single cell gel/Comet assay and the hypoxanthine phosphoribosyl transferase locus assay to 6-thioguanine resistance were used. MX induced a dose-related genotoxic response in the comet assay. The lowest effective concentration was 120 microM when the exposure was in medium plus supplements and 3.75 microM when the exposure was in phosphate-buffered salt solution. MX also increased the frequency of TG(r) mutants, when the cells were treated in phosphate-buffered salt solution, at a concentration range of 2.3-9.2 microM. The present results show for the first time that MX causes DNA damage and gene mutations in rat liver epithelial cells, the target cells of MX's tumorigenicity in rats. We have earlier shown that MX also inhibits gap junctional intercellular communication in the same cells. The genotoxic effects were induced starting at about 60 times higher concentration, in identical exposure conditions, compared with the lowest concentration of MX causing the tumor promoter effect.

Estrogenic effects of toremifene and tamoxifen in postmenopausal breast cancer patients.

Intrinsic estrogenicities of the selective estrogen receptor modulators (SERMs) toremifene 60 mg daily or 200 mg daily and tamoxifen 20 mg daily (TOR60, TOR200 and TAM20) were compared in a randomized clinical study in postmenopausal women with advanced breast cancer. The study was open label in three parallel groups. Variables for analysis were serum follicle stimulating hormone (FSH), luteinizing hormone (LH), sex hormone binding globulin (SHBG), estradiol (E2), antithrombin III (AT III), aspartate aminotransferase (ASAT) and vaginal cytology. Clinical efficacy and safety have been reported earlier. A total of 648 patients were randomized (221 to TOR60, 212 to TOR200 and 215 to TAM20). Sera were available for the analysis from 148, 165 and 156 and for vaginal cytology from 98, 93 and 86 patients, respectively. All treatment regimens showed tissue-specific and dose-dependent estrogen agonist effect. In the primary measure of in vivo estrogenicity, effect on hypothalamus-pituitary-axis, all three treatment regimens decreased serum FSH (p < 0.001). TOR200 was more potent than the two other treatments (p < 0.05), but surprisingly, TAM20 was more estrogenic than TOR60 (p < 0.001). As could be expected in postmenopausal women, the treatments had no effect on mean serum E2 concentrations and decrease of serum LH was similar to that of FSH. Estrogenic effect on the liver was seen as dose-dependent increase of SHBG with statistically significant differences between the treatment groups (p < 0.001). Trends of transient ASAT elevations in TOR200 group (p = 0.07) and in all treatment groups AT III decrease (p = 0.1) were seen in the beginning of the treatment. TOR60 or TAM20 did not have an effect on mean ASAT values, and AT III decreased in TAM20 group more than in the two other groups (p = 0.1 compared to TOR60 and p < 0.05 compared to TOR200). Estrogenic effects on vaginal superficial cells were higher in TOR60 and TOR200 groups when compared to TAM20 (p < 0.05). Toremifene and tamoxifen had tissue-specific and partially dose-dependent estrogenic effects in hypothalamus-pituitary-axis, in the liver and in the vaginal epithelium of postmenopausal women. In some tissues tamoxifen 20 may be more estrogenic than toremifene 60 mg/day.

Dose-dependent hormonal effects of toremifene in postmenopausal breast cancer patients.

PURPOSE: The purpose of the study was to compare hormonal effects of three toremifene doses, 20 mg (TOR20), 40 mg (TOR40) and 60 mg (TOR60) administered daily, in postmenopausal women with advanced breast cancer. METHODS: The study was randomized and open label in three parallel groups. Biochemical variables were identified as the serum concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH) and sex hormone binding globulin (SHBG). The changes were compared with objective clinical responses and to progression-free time. Adverse reactions and liver function test (aspartate aminotransferase, ASAT) were assessed for safety. RESULTS: A total of 260 patients were randomly grouped (90 to TOR20, 81 to TOR40 and 89 to TOR60). Of these patients 29, 29 and 22 completed at least 3 months of treatment and the results were analyzed for biochemical variables. All treatments had intrinsic estrogen agonist activity by decreasing of serum FSH and LH and by increasing of SHBG during the first 3 months (P < 0.01). Dose TOR20 showed slightly longer times to exert maximum estrogenic effects than did the two higher doses. No increases in liver function tests were seen in any of the groups. Objective response rates were 24.4, 39.5 and 32.6% (P = 0.01) and median times-to-progression were 206, 189 and 196 days in TOR20, TOR40 and TOR60, respectively (P = 0.913). Fewer responses were observed in the TOR20 group than in TOR40 (P = 0.05). Adverse events were reported in 19, 23 and 30 patients in the treatment groups (P = 0.20). The most frequently reported events were hot flushes and nausea. These were mostly mild or moderate, and only 1.5% of treatments was discontinued due to toxicity. CONCLUSIONS: Toremifene doses of 40 and 60 mg daily were effective and safe treatments of breast cancer in postmenopausal women, and no differences in their biochemical or clinical effects were seen. Toremifene at 20 mg/day had similar but slightly less potent antiestrogenic and estrogenic effects than the two higher doses.

No consistent pattern of mutations in p53 and ras genes in liver tumors of rat treated with the drinking water mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX).

The frequency of point mutations in p53 (exons 4-7) and in Ki-ras, Ha-ras, and N-ras (exons 1 and 2) and the expression of p53 protein were evaluated in the liver tumors of Wistar rats of a 104-week carcinogenicity study on 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a chlorine disinfection by-product in drinking water. Mutations were analyzed in 16 hepatocellular adenomas, 7 hepatocellular carcinomas, 23 cholangiomas, and 2 cholangiocarcinomas of the MX-treated animals and one hepatocellular carcinoma and cholangiocarcinoma in control animals using PCR-SSCP (polymerase chain reaction-single-strand conformation polymorphism) or PCR-TGGE (temperature gradient gel electrophoresis) and direct sequencing. The expression of the p53 protein (wild-type and mutated protein) was detected by immunohistochemistry (CM5 antibody). The expression of p53 and that of the proliferating cell nuclear antigen (PCNA, 19 A2) were also evaluated in livers of female animals exposed to MX for 1 week, 3 weeks, or 18 weeks. Altogether, four mutations were found in p53 in three tumors, in two hepatocellular adenomas, and one cholangiocarcinoma, all in females receiving the highest MX dose (6. 6 mg/kg/day) of the study. Three of the mutations were G:C --> A:T transitions and one was an A:T --> T:A transversion. The mutations were scattered at different codons and positions of the codon. One hepatocellular adenoma contained two p53 mutations. All cholangiomas and cholangiocarcinomas, but no hepatocellular adenomas and carcinomas, overexpressed the p53 protein. MX treatment did not induce p53 expression at any age in the liver or alter the expression of the PCNA in the liver of younger animals. The p53 protein was overexpressed in hyperplastic bile ducts in aged rats but not in bile ducts of younger rats (up to 24 weeks). No mutations were observed in either Ki-ras, Ha-ras, or N-ras of the liver tumors. These data suggest that point mutations in p53, Ki-ras, Ha-ras, and N-ras are not involved in the MX-induced liver carcinogenesis in rats.

Selegiline as the primary treatment of Parkinson's disease--a long-term double-blind study.

INTRODUCTION: To assess the therapeutic efficacy of selegiline combined with levodopa in the long-term treatment of Parkinson's disease (PD). MATERIAL AND METHODS: A randomized, prospective, double-blind study on 44 patients with PD needing levodopa therapy after the initial double-blind treatment with placebo or selegiline was carried out. The patients were followed-up for 5 years under combination therapy. RESULTS: Selegiline induced a significant (P < 0.001) slowing in the need to increase the daily levodopa dose in order to compensate for the progression of the disease. After 5 years of combination therapy the mean dose of levodopa was on average 320 mg lower in the selegiline group (405 +/- 59 mg vs 725 +/- 78 mg). The difference in the levodopa doses between the two groups increased along with follow-up time, as also the ratio of the levodopa doses (placebo/selegiline group). The number of daily levodopa doses needed to compensate for the occurrence of motor fluctuations was significantly lower in the selegiline group. The parkinsonian disability did not differ between the two groups because the clinical condition was kept as optimal as possible by adjusting the levodopa dosage. Nine patients in the placebo group needed initiation of additional dopaminergic therapy in comparison to one in the selegiline group (P = 0.004). During the 5-year follow-up period 11 patients were withdrawn from the selegiline group, 7 due to adverse events. There was no difference in mortality between the two groups. CONCLUSIONS: Selegiline therapy offers beneficial long-term effets in the treatment of PD.