Applying the adverse outcome pathway concept for assessing non-monotonic dose responses: biphasic effect of bis(2-ethylhexyl) phthalate (DEHP) on testosterone levels

Male reproduction is one of the primary health endpoints identified in rodent studies for some phthalates, such as DEHP (Bis(2-ethylhexyl) phthalate), DBP (Dibutyl phthalate), and BBP (Benzyl butyl phthalate). The reduction in testosterone level was used as an intermediate key event for grouping some phthalates and to establish a reference point for risk assessment. Phthalates, and specifically DEHP, are one of the chemicals for which the greatest number of non-monotonic dose responses (NMDRs) are observed. These NMDRs cover different endpoints and situations, often including testosterone levels. The presence of NMDR has been the subject of some debate within the area of chemical risk assessment, which is traditionally anchored around driving health-based guidance values for apical endpoints that typically follow a clear monotonic dose-response. The consequence of NMDR for chemical risk assessment has recently received considerable attention amongst regulatory agencies, which confirmed its relevance particularly for receptor-mediated effects. The present review explores the relationship between DEHP exposure and testosterone levels, investigating the biological plausibility of the observed NMDRs. The Adverse Outcome Pathway (AOP) concept is applied to integrate NMDRs into Key Event Relationships (KERs) for exploring a mechanistic understanding of initial key events and possibly associated reproductive and non-reproductive adverse outcomes.

[Retrospective cohort study of rituximab biosimilar (Rixathon®) adverse events in adult hematology and pediatric nephrology]

The purpose of this study was to describe rituximab biosimilar safety in adult hematology and pediatric nephrology units. Adverse events were classified using the Common Terminology Criteria for Adverse Events (CTCAE) classification. Fifty adult patients were enrolled for a total of 126 cures and 11 pediatric patients for a total of 24 biosimilar cures. Among adults, three infusion-related reactions of biosimilar occurred : a bronchospasm, a reaction at the injection site and emesis. Among children, infusion-related reactions were: a bronchospasm, an injection site reaction, an emesis, and diarrhea. For adults, the most common adverse events included neutropenia (13.5 %) with 9 severe grade 3/4 cases, anemia (8.7 %), grade 1 thrombocytopenia (6.3 %), asthenia (2.4 %), infection (2.4 %), and chills (1.6 %). For children, a case of severe grade 4 neutropenia, a fever and conjunctivitis were observed. Results of this study show a confident safety profile of rituximab biosimilar in adults and children in «real life».

Simultaneous determination of methanol, acetaldehyde, acetone, and ethanol in human blood by gas chromatography with flame ionization detection

BACKGROUND

Methanol, acetaldehyde, acetone, and ethanol, which are commonly used as biomarkers of several diseases, in acute intoxications, and forensic settings, can be detected and quantified in biological fluids. Gas chromatography (GC)-mass spectrometry techniques are complex, require highly trained personnel and expensive materials. Gas chromatographic determinations of ethanol, methanol, and acetone have been reported in one study with suboptimal accuracy. Our objective was to improve the assessment of these compounds in human blood using GC with flame ionization detection.

METHODS

An amount of 50 µl of blood was diluted with 300 µl of sterile water, 40 µl of 10% sodium tungstate, and 20 µl of 1% sulphuric acid. After centrifugation, 1 µl of the supernatant was injected into the gas chromatograph. We used a dimethylpolysiloxane capillary column of 30 m × 0.25 mm × 0.25 µm.

RESULTS

We observed linear correlations from 7.5 to 240 mg/l for methanol, acetaldehyde, and acetone and from 75 to 2400 mg/l for ethanol. Precision at concentrations 15, 60, and 120 mg/l for methanol, acetaldehyde, and acetone and 150, 600, and 1200 mg/ml for ethanol were 0.8-6.9%. Ranges of accuracy were 94.7-98.9% for methanol, 91.2-97.4% for acetaldehyde, 96.1-98.7% for acetone, and 105.5-111.6% for ethanol. Limits of detection were 0.80 mg/l for methanol, 0.61 mg/l for acetaldehyde, 0.58 mg/l for acetone, and 0.53 mg/l for ethanol.

CONCLUSION

This method is suitable for routine clinical and forensic practices.

Preliminary risk analysis applied to the transmission of Creutzfeldt-Jakob disease

Transmissible spongiform encephalopathy (TSE) is a degenerative disease of the central nervous system. As yet, there is no human screening test and no effective treatment. This disease is invariably fatal. General preventive measures are therefore essential. The objective of this study is to analyze and address on a prioritized basis the risks relating to the transmission of Creutzfeldt-Jakob disease during surgical operations by means of a preliminary risk analysis (PRA). The PRA produces 63 scenarios with maximum risk relating to operational and legal dangers. The study recommends a number of courses of action, such as training and internal controls, in order to reduce the risks identified. A procedure has been drawn up and assessed for each action. This PRA makes it possible to target and significantly reduce the potential dangers for transmission of Creutzfeldt-Jakob disease through the use of medical instruments.

Map of risks for the implementation of radio-frequency identification: application of ancillaries in the University Hospital Jean Verdier

Ancillaries are surgical instruments, such as orthopedical instruments set for reconstruction of knee (a mounting arm...) used to implant or extract prosthesis. Their management involves the departments of sterilization and surgery as well as the suppliers. Such a long circuit exposes the instruments to potential risk hazards like a lack of traceability as the suspicion of Creutzfeldt-Jakob. In order to reduce the risk of errors we will propose the implementation of radio-frequency identification (RFID) to trace the ancillaries during each step of the supply chain. The objective of our study is to analyze and to map the risks associated with RFID implementation. A preliminary analysis of risks (APR) is conducted to map out the hazards for the implementation of RFID. The APR identifies 162 scenarios with a maximum risk connected to environment and technology. To reduce the risks identified, 22 courses of action are proposed, such as audits, training, and internal controls. For each action, a procedure has been designed and evaluated. This preliminary analysis of risks allows targeting the potential dangers for the RFID implementation applied to ancillaries and reduces them significantly.

Association between folate, vitamin B(6) and vitamin B(12) intake and depression in the SUN cohort study

BACKGROUND

An association between low blood levels of folate, vitamins B(6) and B(12) and a higher prevalence of depressive symptoms has been reported in several epidemiological studies. The present study aimed to assess the association between folate, vitamins B(6) and B(12) intake and depresion prevalence in the SUN cohort study.

METHODS

The study comprised a cross-sectional analysis of 9670 participants. A validated semi-quantitative food frequency questionnaire was used to ascertain vitamin intake. The association between the baseline intake of folate, vitamins B(6) and B(12) categorised in quintiles and the prevalence of depression was assessed. The analyses were repeated after stratifying by smoking habits, alcohol intake, physical activity and personality traits.

RESULTS

Among women, odds ratios (OR) [95% confidence interval (CI)] for the third to fifth quintile for vitamin B(12) intake were 0.58 (0.41-0.84), 0.56 (0.38-0.82) and 0.68 (0.45-1.04), respectively. Among those men with a low level of anxiety and current smokers, a significant positive association between low folate intake and the prevalence of depression was found. The OR (95% CI) for the first quintile of intake was 2.85 (1.49-5.45) and 2.18 (1.08-4.38), respectively, compared to the upper quintiles of intake (Q2-Q5) considered as a group.

CONCLUSION

Low folate intake was associated with depression among currently smoking men and men with low anxiety levels. Low intake of vitamin B(12) was associated with depression among women. No significant associations were found for vitamin B(6) intake.

Evaluation of certain food additives and contaminants

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to recommending acceptable daily intakes (ADIs) and to preparing specifications for identity and purity. The Committee also evaluated the risk posed by two food contaminants, with the aim of advising on risk management options for the purpose of public health protection. The first part of the report contains a general discussion of the principles governing the toxicological evaluation and assessment of intake of food additives (in particular flavouring agents) and contaminants. A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food additives (acidified sodium chlorite, asparaginase from Aspergillus oryzae expressed in Aspergillus oryzae, carrageenan and processed Eucheuma seaweed, cyclotetraglucose and cyclotetraglucose syrup, isoamylase from Pseudomonas amyloderamosa, magnesium sulfate, phospholipase A1 from Fusarium venenatum expressed in Aspergillus oryzae, sodium iron(III) ethylenediaminetetraacetic acid (EDTA) and steviol glycosides); eight groups of related flavouring agents (linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; aliphatic acyclic and alicyclic terpenoid tertiary alcohols and structurally related substances; simple aliphatic and aromatic sulfides and thiols; aliphatic acyclic dials, trials and related substances; aliphatic acetals; sulfur-containing heterocyclic compounds; aliphatic and aromatic amines and amides; and aliphatic alicyclic linear alpha, beta -unsaturated di- and trienals and related alcohols, acids and esters); and two food contaminants (aflatoxin and ochratoxin A). Specifications for the following food additives were revised: maltol and ethyl maltol, nisin preparation, pectins, polyvinyl alcohol, and sucrose esters of fatty acids. Specifications for the following flavouring agents were revised: maltol and ethyl maltol, maltyl isobutyrate, 3-acetyl-2,5-dimethylfuran and 2,4,5-trimethyl-delta-oxazoline (Nos 1482, 1506 and 1559), and monomenthyl glutarate (No. 1414), as well as the method of assay for the sodium salts of certain flavouring agents. Annexed to the report are tables summarizing the Committee's recommendations for intakes and toxicological evaluations of the food additives and contaminants considered.

Approaches to the risk assessment of genotoxic carcinogens in food: A critical appraisal

The present paper examines the particular difficulties presented by low levels of food-borne DNA-reactive genotoxic carcinogens, some of which may be difficult to eliminate completely from the diet, and proposes a structured approach for the evaluation of such compounds. While the ALARA approach is widely applicable to all substances in food that are both carcinogenic and genotoxic, it does not take carcinogenic potency into account and, therefore, does not permit prioritisation based on potential risk or concern. In the absence of carcinogenicity dose-response data, an assessment based on comparison with an appropriate threshold of toxicological concern may be possible. When carcinogenicity data from animal bioassays are available, a useful analysis is achieved by the calculation of margins of exposure (MOEs), which can be used to compare animal potency data with human exposure scenarios. Two reference points on the dose-response relationship that can be used for MOE calculation were examined; the T25 value, which is derived from linear extrapolation, and the BMDL10, which is derived from mathematical modelling of the dose-response data. The above approaches were applied to selected food-borne genotoxic carcinogens. The proposed approach is applicable to all substances in food that are DNA-reactive genotoxic carcinogens and enables the formulation of appropriate semi-quantitative advice to risk managers.

Risk assessment of substances that are both genotoxic and carcinogenic

The European Food Safety Authority (EFSA) and the World Health Organization (WHO), with the support of the International Life Sciences Institute, European Branch (ILSI Europe), organized an international conference on 16-18 November 2005 to discuss how regulatory and advisory bodies evaluate the potential risks of the presence in food of substances that are both genotoxic and carcinogenic. The objectives of the conference were to discuss the possible approaches for risk assessment of such substances, how the approaches may be interpreted and whether they meet the needs of risk managers. ALARA (as low as reasonably achievable) provides advice based solely on hazard identification and does not take into account either potency or human exposure. The use of quantitative low-dose extrapolation of dose-response data from an animal bioassay raises numerous scientific uncertainties related to the selection of mathematical models and extrapolation down to levels of human exposure. There was consensus that the margin of exposure (MOE) was the preferred approach because it is based on the available animal dose-response data, without extrapolation, and on human exposures. The MOE can be used for prioritisation of risk management actions but the conference recognised that it is difficult to interpret it in terms of health risk.

Oxidative stress related DNA adducts in the liver of female rats fed with sunflower-, rapeseed-, olive- or coconut oil supplemented diets

Both animal and epidemiological studies support an effect of fatty acid composition in the diet on cancer development, in particular on colon cancer. We investigated the modulating effect of supplementation of the diet of female F344 rats with sunflower-, rapeseed-, olive-, or coconut oil on the formation of the promutagenic, exocyclic DNA adducts in the liver, an organ where major metabolism of fatty acids takes place. 1,N(6)-ethenodeoxyadenosine (etheno-dA), 3,N(4)-ethenodeoxycytidine (etheno-dC) and 1,N(2)-propandodeoxyguanosine from 4-hydroxy-2-nonenal (HNE-dGp) were determined as markers for DNA-damage derived from lipid peroxidation products and markers for oxidative stress. 8-Oxo-deoxyguanosine (8-Oxo-dG) was also measured as direct oxidative stress marker. The body weight of the rats was not influenced by the four diets containing the different vegetable oils during the 4-week feeding period. Highest adduct levels of etheno-dC (430 +/- 181 adducts/10(9) parent bases), HNE-dGp (617 +/- 96 adducts/10(9) parent bases) and 8-Oxo-dG (37,400 +/- 12,200 adducts/10(9) parent bases) were seen in rats on sunflower oil diet (highest linoleic acid content). Highest adducts levels of etheno-dA (133 +/- 113 adducts/10(9) parent bases) were found in coconut oil diet (lowest content of linoleic acid). Weakly positive correlations between linoleic acid content in the four diet groups were only observed for levels of HNE-dGp and 8-Oxo-dG. Neither the diet based on olive oil (which contains mainly oleic acid) nor the diet based on rapeseed oil (containing alpha-linolenic acid) exerted any significant protective effect against oxidative DNA damage. Our results indicate that a high linoleic acid diet may contribute to oxidative stress in the liver of female rats leading to a marginal increase in oxidative DNA-damage.

Interactions médicamenteuses dans une population âgée

OBJECTIVE

To assess the nature and the number of potential adverse drug interactions by analysis of outpatient prescriptions for elderly patients, of medications taken during the week before hospitalization in a general surgery department.

METHOD

The study of 56 patients older than 65 years was conducted from November 2002 through February 2003. The outpatient prescriptions corresponding to medications taken during the 7 days before admission were analyzed by a pharmacy resident, who used data-processing tools and databases.

RESULTS

Most patients (83%) knew the reason for their prescription. Thirteen (28%) reported using over-the-counter medication. Only 89% of the patients reported complete compliance with the prescription. The average age of the patients was 72.1 +/- 6.3 years and the median was 71 years [65-91]; 43% were women and 57% men. The 257 lines of prescriptions analyzed averaged 5.7 +/- 2.6 drugs (range: 2-10) per prescription. The average number of possible interactions was 3.1 +/- 2.8 per prescription for a total of 89 listed potential interactions. The levels observed were 3 warnings (3%), 37 precautions (42%) and 49 possible adverse interactions (55%). No contraindication was noted. The drugs mentioned most often were benzodiazepines, diuretics, conversion enzyme inhibitors, angiotensin II inhibitors, and beta-blockers. The potential risks most often found were hypotension, depression of the central nervous system, hypoglycemia and acute renal failure. The drug interactions were mainly due to the accumulation of the effects of separate drug classes. Deterioration in renal function was often noted as plasma concentration of the second drug increased.

DISCUSSION

This exploratory study shows the reality of the iatrogenic risk for elderly patients. This analysis of outpatient prescriptions is consistent with findings in the literature. Analysis of interactions is conducted on a pairwise basis. It is thus difficult to envisage the consequences of the association of 5 or more drugs in patients with complex illnesses and diminished physiological and metabolic capacity. Patient files kept by the pharmacist could provide information about individual combinations ofthe prescription and over-the-counter drugs.

Stability of doxorubicin combined with RadioselectanR, a contrast agent, for chemoembolization

OBJECTIVE

To assess the stability of doxorubicin combined with Radioselectan.

METHODS

Solutions of doxorubicin 5 mg/mL were prepared from commercially available 50 mg powder with 10 mL of Radioselectan. They were stored in glass syringes at 4, 25 and 45 degrees C. The concentrations of doxorubicin were determined using a stability-indicating high-performance liquid chromatography method. The initial and final pHs of solutions were compared. The times (t90) needed for doxorubicin to fall to 90% of its initial concentration were calculated by a linear regression analysis.

RESULTS

The t90 [95% confidence limits] were 79 [75-83], 56 [53-59] and 22 [21-23] hours for the solutions stored at 4, 25 and 40 degrees C respectively. The initial pH of the solutions stored at 4, 25 and 40 degrees C were 6.52, 6.50 and 6.51 respectively. The final pH of solutions stored at 25 and 40 degrees C decreased significantly by 0.3 and 0.9 respectively. No change of pH solution stored at 4 degrees C was observed.

CONCLUSION

Doxorubicin combined with Radioselectan stored at room temperature is stable for 48 h.

Human exposure and internal dose assessments of acrylamide in food

This review provides a framework contributing to the risk assessment of acrylamide in food. It is based on the outcome of the ILSI Europe FOSIE process, a risk assessment framework for chemicals in foods and adds to the overall framework by focusing especially on exposure assessment and internal dose assessment of acrylamide in food. Since the finding that acrylamide is formed in food during heat processing and preparation of food, much effort has been (and still is being) put into understanding its mechanism of formation, on developing analytical methods and determination of levels in food, and on evaluation of its toxicity and potential toxicity and potential human health consequences. Although several exposure estimations have been proposed, a systematic review of key information relevant to exposure assessment is currently lacking. The European and North American branches of the International Life Sciences Institute, ILSI, discussed critical aspects of exposure assessment, parameters influencing the outcome of exposure assessment and summarised data relevant to the acrylamide exposure assessment to aid the risk characterisation process. This paper reviews the data on acrylamide levels in food including its formation and analytical methods, the determination of human consumption patterns, dietary intake of the general population, estimation of maximum intake levels and identification of groups of potentially high intakes. Possible options and consequences of mitigation efforts to reduce exposure are discussed. Furthermore the association of intake levels with biomarkers of exposure and internal dose, considering aspects of bioavailability, is reviewed, and a physiologically-based toxicokinetic (PBTK) model is described that provides a good description of the kinetics of acrylamide in the rat. Each of the sections concludes with a summary of remaining gaps and uncertainties.

[Fast diagnostic tests in the management of group A beta-heamolytic streptococcal pharyngitis]

OBJECTIVE

Routine clinical diagnosis of Streptococcus pyogenes in pharyngitis is not always easy. The use in common practice of rapid diagnosis test (RDT), might offer a best control of the antibiotic treatments. The aim of this study is to present seven rapid diagnosis tests, to assess their feasibility and finally to determine the bacteriological correlation.

METHOD

We propose to compare the results obtained with seven RDT, and to assess their interest in medical diagnosis for group A streptococcus pharyngitis. A prospective study was conducted for three months, a RDT was performed for children (n=75) between eight and fourteen years old presenting acute pharyngitis. Several throat sampling were performed to order cultures.

RESULTS

The group A streptococcus was isolated in 33% (n=25) of throat sampling. Comparing cultures results, and for all studied tests, we obtained comparable performances with manufacturer data, specificity upper than 94% and sensitivity upper than 88%.

CONCLUSION

All assessed RDT may offer to physicians a decision-making tool for rapid diagnosis. However, because of its complexity, the agglutination test can be used only in pathology laboratories.

Structure-based thresholds of toxicological concern (TTC): guidance for application to substances present at low levels in the diet

The threshold of toxicological concern (TTC) is a pragmatic risk assessment tool that is based on the principle of establishing a human exposure threshold value for all chemicals, below which there is a very low probability of an appreciable risk to human health. The concept that there are levels of exposure that do not cause adverse effects is inherent in setting acceptable daily intakes (ADIs) for chemicals with known toxicological profiles. The TTC principle extends this concept by proposing that a de minimis value can be identified for many chemicals, in the absence of a full toxicity database, based on their chemical structures and the known toxicity of chemicals which share similar structural characteristics. The establishment and application of widely accepted TTC values would benefit consumers, industry and regulators. By avoiding unnecessary toxicity testing and safety evaluations when human intakes are below such a threshold, application of the TTC approach would focus limited resources of time, cost, animal use and expertise on the testing and evaluation of substances with the greatest potential to pose risks to human health and thereby contribute to a reduction in the use of animals. An Expert Group of the European branch of the International Life Sciences Institute-ILSI Europe-has examined the TTC principle for its wider applicability in food safety evaluation. The Expert Group examined metabolism and accumulation, structural alerts, endocrine disrupting chemicals and specific endpoints, such as neurotoxicity, teratogenicity, developmental toxicity, allergenicity and immunotoxicity, and determined whether such properties or endpoints had to be taken into consideration specifically in a step-wise approach. The Expert Group concluded that the TTC principle can be applied for low concentrations in food of chemicals that lack toxicity data, provided that there is a sound intake estimate. The use of a decision tree to apply the TTC principle is proposed, and this paper describes the step-wise process in detail. Proteins, heavy metals and polyhalogenated-dibenzodioxins and related compounds were excluded from this approach. When assessing a chemical, a review of prior knowledge and context of use should always precede the use of the TTC decision tree. The initial step is the identification and evaluation of possible genotoxic and/or high potency carcinogens. Following this step, non-genotoxic substances are evaluated in a sequence of steps related to the concerns that would be associated with increasing intakes. For organophosphates a TTC of 18microg per person per day (0.3 microg/kg bw/day) is proposed, and when the compound is not an OP, the TTC values for the Cramer structural classes III, II and I, with their respective TTC levels (e.g. 1800, 540 and 90 microg per person per day; or 30, 9 and 1.5 microg/kg bw /day), would be applied sequentially. All other endpoints or properties were shown to have a distribution of no observed effect levels (NOELs) similar to the distribution of NOELs for general toxicity endpoints in Cramer classes I, II and III. The document was discussed with a wider audience during a workshop held in March 2003 (see list of workshop participants).

Study of the toxicity of a new lipid complex formulation of amphotericin B

OBJECTIVES

The aim of this study was to evaluate the toxicity of a new lipid complex formulation of amphotericin B (LC-AmB) produced by a simple process.

METHODS

Toxicity was evaluated after daily administration for 21 consecutive days in female CD1 mice. Doses of LC-AmB up to 20 mg/kg were used, and compared with Fungizone at 0.5 mg/kg and Abelcet at 10 mg/kg. Acute toxicity after a single bolus injection was also determined, as well as the haemolytic activity and toxicity to mouse macrophages in vitro.

RESULTS

LC-AmB reduced both the haemolytic activity of amphotericin B and its toxicity towards mouse peritoneal macrophages. Its acute toxicity (LD50 > 200 mg/kg in CD1 mice) was similar to that in the literature for the least toxic lipid formulations of amphotericin B. The relative liver weight increased slightly in mice treated daily with a dose of 20 mg/kg LC-AmB, as did the kidney weight in this group and the group treated with Fungizone. There was also a dose-dependent decrease in the haematocrit with all formulations. All treatments caused significant increases in transaminase levels. Total hepatic CYP 450 was slightly but not significantly increased in the groups treated with 20 mg/kg LC-AmB, Abelcet and Fungizone. However, expression of some isoforms of CYP 450 was reduced, the most marked being the hepatic CYP 3A1 after treatment with 20 mg/kg LC-AmB, Abelcet and Fungizone. The effects on hepatic function are probably related to accumulation in organs rich in phagocytic cells.

CONCLUSION

LC-AmB did not induce any new toxicity compared with Abelcet and Fungizone.

Stability of fludrocortisone acetate solutions prepared from tablets and powder

To assess the stability of fludrocortisone acetate oral solutions prepared from tablets and powder at three temperatures over a 60-days period. Solutions of fludrocortisone acetate 40 microg/ml were prepared from commercially available 0.05-mg tablets and powder in ethanol 17% v/v. They stored in an amber glass prescription bottles at +4, +23 and +40 degrees C shielded from light. The concentrations of fludrocortisone acetate were determined in duplicate by high-performance liquid chromatography at 0, 1, 7, 14, 30, 50 and 60 days. The initial and final pH of solutions were compared. The recovery of fludrocortisone acetate from tablets was determined. The times (t(90)) needed for fludrocortisone acetate to fall to 90% of it's initial concentration were calculated by a linear regression analysis to allow the determination of the expired dates. The recovery of fludrocortisone acetate from tablets was 78 +/- 3%. The t(90) expressed with 95% confidence limits were 2 +/- 1 and 22 +/- 3 days for the solutions prepared from tablets and stored at +23 and +4 degrees C, respectively, whereas t(90) were 11 +/- 2 days and at least 60 days for the solutions prepared with the powder and stored at +23 and +4 degrees C, respectively. No color or odour changes were observed during the study period. The initial pH of the solutions prepared from tablets and powder were 7.7 and 6.9, respectively. No change of pH values was observed at the end of the 60 days. Significant degradation of fludrocortisone acetate occurred in formulations stored at +23 degrees C. Fludrocortisone acetate 40 microg/ml solutions prepared from tablets and powder were stable 19 days and at least 60 days, respectively, when stored at +4 degrees C. The solution prepared from powder is the best in term of stability and final concentration which is independent on the fludrocortisone acetate recovery.

Hazard characterisation of chemicals in food and diet. dose response, mechanisms and extrapolation issues

Hazard characterisation of low molecular weight chemicals in food and diet generally use a no-observed-adverse-effect level (NOAEL) or a benchmark dose as the starting point. For hazards that are considered not to have thresholds for their mode of action, low-dose extrapolation and other modelling approaches may be applied. The default position is that rodents are good models for humans. However, some chemicals cause species-specific toxicity syndromes. Information on quantitative species differences is used to modify the default uncertainty factors applied to extrapolate from experimental animals to humans. A central theme for extrapolation is unravelling the mode of action for the critical effects observed. Food can be considered as an extremely complex and variable chemical mixture. Interactions among low molecular weight chemicals are expected to be rare given that the exposure levels generally are far below their NOAELs. Hazard characterisation of micronutrients must consider that adverse effects may arise from intakes that are too low (deficiency) as well as too high (toxicity). Interactions between different nutrients may complicate such hazard characterisations. The principle of substantial equivalence can be applied to guide the hazard identification and hazard characterisation of macronutrients and whole foods. Macronutrients and whole foods must be evaluated on a case-by-case basis and cannot follow a routine assessment protocol.

Differences in interleukins' patterns between dysthymia and major depression

We assessed whether cytokine production-interleukin (IL)-1beta, IL-6 and tumour necrosis factor-alpha (TNFalpha)-is affected in depressed patients, dysthymia (Dt) and major depression (MD), and its association with various parameters of severity and clinical course. We found a possible different pattern of interleukin production between Dt and MD.

Occurrence of heterocyclic aromatic amines in the Swiss diet: analytical method, exposure estimation and risk assessment

A total of 86 meat samples, prepared in restaurants or homes, ready to eat (including poultry and fish) and 16 commercial samples such as bouillon (cubes) were analysed for heterocyclic aromatic amines (HAA). The analytical method consisted of an acidic extraction, clean-up on a cation exchange cartridge followed by an analogous HPLC step to recover the following HAA: IQ, MeIQ, MeIQx, 4,8-DiMeIQx, PhIP and 7,8-DiMeIQx. The HAA containing HPLC-fractions were collected, the HAA identified and quantified using two RP-HPLC-systems of different retention properties (UV-detection). The limit of quantitation was in the range of 0.2-0.4 ng/g and the relative repeatability 6-15%. The recovery of PhIP was lower than for the other HAA analysed (less than 80%) and a correction factor was applied. No significant differences of the HAA-concentration were found in samples from homes and restaurants, half of the total samples contained HAA at the following frequencies: PhIP and MeIQx 33% (each), 4,8-DiMeIQx 11% and MeIQ 4%; 7,8-DiMeIQx and IQ were not detected. The frequencies in commercial products were for MeIQx 31%, 7,8-DiMeIQx 19%, IQ 13% and PhIP 6%; MeIQ and 4,8-DiMeIQx were not found. Based on these data, the average exposure of Swiss adults to HAA was estimated to be 5 ng/kg body mass per day, commercial products contributing less than 10%. The theoretical excess cancer risk due to this intake was estimated on the base of the carcinogenic potency of the HAA in long-term animal experiments by linear extrapolation. The resulting risk in the order of 10(-4) at the maximum is discussed in terms of Swiss epidemiological data.

[Drugs and drug abusers]

DRUG ABUSERS: Drugs are widely used by toxicomaniacs to reproduce drug effects. Drug abusers generally start with psychotrops, but other abuse drug classes. Toxicomanic behavior leads to addictive practices that are difficult to control. BARBITURATES: Both the oral and intravenous routes are used. The expected result is a state of ecstasy with a feeling of comfort. Intoxication may cause respiratory depression. Barbiturates induce physical and psychic dependence. Abuse is not widespread with this class of drugs. BENZODIAZEPINES: Drug abuses widely use benzodiazepines orally or intravenously. They search for a flash effect, with sedation and a feeling of comfort. All benzodiazepines induce physical and psychic dependence. Death may result from combinations leading to respiratory depression. Flunitrazepam is the most widely abused benzodiazepine in France. It induces serious neuropsychic disorders. ANTIDEPRESSANTS: Few are used, mostly at high doses. OPIATES: Administration gives the same effect as heroine injection. Opiates induce physical and psychic dependence. The adverse effects are similar to those of morphine with a higher risk of respiratory depression. AMPHETAMINES: Few are used, either orally or intravenously. They induce a flash with excitation, euphoria, and a period of invincibility. This is followed by a period of depression with risk of suicide. Psychic dependence is high. ANTICHOLINERGIC ANTIPARKINSONIANS: These drugs are well known to abusers for their hallucinatory effect. They induce atropinic adverse effects and physical and psychic dependence. GAMMA-HYDROXYBUTYRATE: This anesthetic is used for its euphoria and sedation effects. It may induce falling sickness or coma, with a risk of respiratory depression. KETAMINE: Administered via the intranasal route, ketamine induces a state of indifference. Death has been observed. ANABOLIC AND ANDROGENIC STEROIDS: These drugs are used for their physical and psychic stimulating effect. They induce potentially dangerous adverse effects such as cardiovascular, hepatic, neurological and psychiatric disorders. Clinical signs of addiction and weaning are observed. OTHERS: Several other drug classes are used by abusers, including analgics, beta-adrenergic agents, nasal vasoconstrictors and corticosteroids.

Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans

The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng 3H-labeled OTA (3.8 microCi). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T1/2 about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes.

5-Hydroxymethylfurfural: assessment of mutagenicity, DNA-damaging potential and reactivity towards cellular glutathione

5-(hydroxymethyl)-2-furfural (HMF), a common product of the Maillard reaction, occurs in many foods in high concentrations, sometimes exceeding 1 g/kg (in certain dried fruits and caramel products). The toxicological relevance of this exposure has not yet been clarified. Induction of aberrant colonic crypt foci had been reported for HMF, in vitro studies on genotoxicity/mutagenicity have given controversial results. To elucidate the toxic potential of HMF, cytotoxicity (trypan blue exclusion), growth inhibition (SRB assay), mutagenicity (HPRT assay), DNA damage (single-cell gel electrophoresis) and depletion of cellular glutathione were investigated in mammalian cells. Genotoxicity (SOS repair) was monitored in Salmonella typhimurium (umu assay). HMF induced moderate cytotoxicity in V79 cells (LC(50): 115 mM, 1 hr incubation) and in Caco-2 cells (LC(50): 118 mM, 1 hr incubation). Growth inhibition was monitored following 24 hr of incubation (V79, IC(50): 6.4 mM). DNA damage was detectable neither in these cell lines nor in primary rat hepatocytes up to the cytotoxic threshold concentration (75% absolute viability). Likewise, in primary human colon cells, obtained from biopsy material, DNA damage was not measurable. At 120 mM, already exhibiting some reduction in cell viability, HMF was weakly mutagenic at the hprt-locus in V79 cells (mutants/10(6) cells: HMF 120 mM: 16 vs control: 3). Intracelluar glutathione was depleted by HMF (>/=50 mM) in V79 cells, in the human colon adenocarcinoma cell line Caco-2 and in primary rat hepatocytes down to approximately 30% of control (120 mM). Genotoxicity was observed with HMF in the umu assay without external activation (16 mM: 185 rel. umu units, %, P<0.001). The genotoxic potential was not altered by addition of rat liver microsomes. By comparison, the natural flavour constituent (E)-2-hexenal (HEX) was already cytotoxic, mutagenic and depleted glutathione at about 1000-fold lower concentrations. It induced DNA damage in mammalian cells (200-400 microM). These results suggest that HMF does not pose a serious health risk, even though the highest concentrations in specific foods approach the biologically effective concentration range in cell systems.

[Drug interactions with methadone]

PHARMACOKINETICS PHARMACODYNAMICS: Methadone is metabolized by cytochrome P450 enzymes in the liver microsomes and binds selectively to mu opiate receptors. Drugs metabolized by these enzymes or mu receptor competitors can modify the action of methadone. Genetic polymorphism influences plasma concentrations of the active levo enantiomer and thus clinical efficacy. ANTITUBERCULOSIS DRUGS: Rifampicin lowers methadome plasma levels so dose must be adapted. Rifabutin does not affect methadone kinetics. ANTI-EPILEPSY DRUGS: Phenytoin lowers blood levels of methadone by about 50% in 3 to 4 days. Other anti-epilepsy enzyme inducers (phenobarbital, carbamazepine) increase methadone metabolism. ANTI-VIRAL DRUGS: The area under the curve of plasma concentrations of zidovudine in presence of methadone increase by 43%, increasing the risk of undesirable effects. PSYCHOTROPES: Plasma levels of methadone increase by 20 to 100% in the presence of fluvoxamine. The benzodiazepine-methadone combination can be fatal due to respiratory depression. OTHER DRUGS: Brupenophine is a methadone agonist at the dose of 1 and 2 mg. Chronic alcoholism reduces the area under the curve while acute alcoholism increases it. Pure morphine agonists raise a major risk of respiratory depression while partial agonists favor the development of withdrawal symptoms.

Population pharmacokinetics of methotrexate in the guinea pig

The population pharmacokinetics of an antitumoral and antiinflammatory agent, methotrexate (MTX), a folic acid antagonist, was studied in guinea pigs. Animals received an acute intraperitoneal injection of 0.25, 1 or 5 mg/kg MTX. Blood sampling was carried out for 12 hrs. after MTX administration and plasma drug concentrations were measured by fluorescence polarization immunoassay. The pharmacokinetic (PK) parameters were computed using the bayesian population model. MTX reached the level of detection at 3 hrs. for the animals injected with the lowest dose (0.25 mg/kg), at 3.5 hrs. for those animals which had the intermediate dose (1 mg/kg) and more than 6 hrs. for animals having received the highest dose (5 mg/kg). Each kinetic parameter (half life, total clearance - CLt, volume of distribution at steady state - VDSS, mean residence time - MRT - and area under curve - AUC) didn't show any significant difference between doses. MTX kinetic was linear for the first two doses (0.25 and 1 mg/kg MTX) and non-linear thereafter. MTX presented a one compartment distribution.

Occurrence of emodin, chrysophanol and physcion in vegetables, herbs and liquors. Genotoxicity and anti-genotoxicity of the anthraquinones and of the whole plants

1,8-Dihydroxyanthraquinones, present in laxatives, fungi imperfecti, Chinese herbs and possibly vegetables, are in debate as human carcinogens. We screened a variety of vegetables (cabbage lettuce, beans, peas), some herbs and herbal-flavoured liquors for their content of the 'free' anthraquinones emodin, chrysophanol and physcion. For qualitative and quantitative analysis, reversed-phase HPLC (RP-LC), gas chromatography-mass spectrometry (GC-MS) and RP-LC-MS were used. The vegetables showed a large batch-to-batch variability, from 0.04 to 3.6, 5.9 and 36 mg total anthraquinone per kg fresh weight in peas, cabbage lettuce, and beans, respectively. Physcion predominated in all vegetables. In the herbs grape vine leaves, couch grass root and plantain herb, anthraquinones were above the limit of detection. Contents ranged below 1 mg/kg (dry weight). All three anthraquinones were also found in seven of 11 herbal-flavoured liquors, in a range of 0.05 mg/kg to 7.6 mg/kg. The genotoxicity of the analysed anthraquinones was investigated in the comet assay, the micronucleus test and the mutation assay in mouse lymphoma L5178Y tk+/- cells. Emodin was genotoxic, whereas chrysophanol and physcion showed no effects. Complete vegetable extract on its own did not show any effect in the micronucleus test. A lettuce extract completely abolished the induction of micronuclei by the genotoxic anthraquinone danthron. Taking into consideration the measured concentrations of anthraquinones, estimated daily intakes, the genotoxic potency, as well as protective effects of the food matrix, the analysed constituents do not represent a high priority genotoxic risk in a balanced human diet.

Selected phenolic compounds in cultivated plants: ecologic functions, health implications, and modulation by pesticides

Phenolic compounds are widely distributed in the plant kingdom. Plant tissues may contain up to several grams per kilogram. External stimuli such as microbial infections, ultraviolet radiation, and chemical stressors induce their synthesis. The phenolic compounds resveratrol, flavonoids, and furanocoumarins have many ecologic functions and affect human health. Ecologic functions include defense against microbial pathogens and herbivorous animals. Phenolic compounds may have both beneficial and toxic effects on human health. Effects on low-density lipoproteins and aggregation of platelets are beneficial because they reduce the risk of coronary heart disease. Mutagenic, cancerogenic, and phototoxic effects are risk factors of human health. The synthesis of phenolic compounds in plants can be modulated by the application of herbicides and, to a lesser extent, insecticides and fungicides. The effects on ecosystem functioning and human health are complex and cannot be predicted with great certainty. The consequences of the combined natural and pesticide-induced modulating effects for ecologic functions and human health should be further evaluated.

The role of alpha2u-globulin in ochratoxin A induced renal toxicity and tumors in F344 rats

The mycotoxin ochratoxin A (OTA) was shown to be a potent kidney carcinogen in rats demonstrating a marked sex difference in the response. Compared to female rats, male rats had a 10-fold higher incidence of kidney carcinomas. The objective of this study was to investigate whether this sex difference in tumor response is due to an exacerbation of effect resulting from the interaction of the male rat specific urinary protein alpha2u-globulin (alpha2u) with OTA. Male and female rats were treated by oral gavage with OTA (1 mg/kg per day), D-limonene (dL; 1650 mg/kg per day) as a positive control or corn oil for 7 consecutive days. OTA induced severe renal lesions predominantly in the P3 region of the proximal tubules. The lesions consisted of necrotic cells and cell exfoliations. No hyaline droplets were found in the P2 segment following OTA treatment, whereas dL induced the expected accumulation of droplets. The results suggest that OTA induced kidney lesions are in all characteristic points different from the known alpha2u-nephropathy induced by dL. Based on these experiments the male rat specific protein alpha2u does not seem to be involved in the mechanism(s) leading to the high tumor incidence observed in OTA exposed male rats.

Determination of cisapride and norcisapride in human plasma using high-performance liquid chromatography with ultraviolet detection

A simple, rapid and reproducible high-performance liquid chromatographic assay for cisapride and norcisapride in human plasma is described. Samples of plasma (150 microl) were extracted using a C18 solid-phase cartridge. Regenerated tubes were eluted with 1.0 ml of methanol, dried, redissolved in 150 microl of methanol and injected. Chromatography was performed at room temperature by pumping acetonitrile-methanol-0.015 M phosphate buffer pH 2.2-2.3 (680:194:126, v/v/v) at 0.8 ml/min through a C18 reversed-phase column. Cisapride, norcisapride and internal standard were detected by absorbance at 276 nm and were eluted at 4.3, 5.3 and 8.1 min, respectively. Calibration plots in plasma were linear (r>0.998) from 10 to 150 ng/ml. Intraday precisions for cisapride and norcisapride were 3.3% and 5.4%, respectively. Interday precisions for cisapride and norcisapride were 9.6% and 9.0%, respectively. Drugs used which might be coadministered were tested for interference.

Dose response for the stimulation of cell division by caffeic acid in forestomach and kidney of the male F344 rat

Caffeic acid (CA, 3,4-dihydroxycinnamic acid), at 2% in the diet, had been shown to be carcinogenic in forestomach and kidney of F344 rats and B6C3F1 mice. Based on its occurrence in coffee and numerous foods and using a linear interpolation for cancer incidence between dose 0 and 2%, the cancer risk in humans would be considerable. In both target organs, tumor formation was preceded by hyperplasia, which could represent the main mechanism of carcinogenic action. The dose-response relationship for this effect was investigated in male F344 rats after 4-week feeding with CA at different dietary concentrations (0, 0.05, 0.14, 0.40, and 1.64%). Cells in S-phase of DNA replication were visualized by immunohistochemical analysis of incorporated 5-bromo-2'-deoxyuridine (BrdU), 2 hr after intraperitoneal injection. In the forestomach, both the total number of epithelial cells per millimeter section length and the unit length labeling index of BrdU-positive cells (ULLI) were increased, about 2.5-fold, at 0.40 and 1.64%. The lowest concentration (0.05%) had no effect. At 0.14%, both variables were decreased by about one-third. In the kidney, the labeling index in proximal tubular cells also indicated a J-shaped (or U-shaped) dose response with a 1. 8-fold increase at 1.64%. In the glandular stomach and in the liver, which are not target organs, no dose-related effect was seen. The data show a good correlation between the organ specificity for cancer induction and stimulation of cell division. With respect to the dose-response relationship and the corresponding extrapolation of the animal tumor data to a human cancer risk, a linear extrapolation appears not to be appropriate.

Dexamethasone and flumethasone residues in milk of intramuscularly dosed cows

A field study was performed to assess the level of drug residues in milk after therapeutic application of highly potent synthetic glucocorticoids. Dexamethasone was tested either as a crystalline suspension or as a combination of sodium phosphate and phenylpropionate esters. Intramuscular injection of these preparations in lactating dairy cows (60 micrograms dexamethasone/kg body wt) yielded drug residues in milk of up to 8.4 ng/mL 12 h after treatment. These dexamethasone residues fell to below 1.0 ng/mL within 3 days after treatment. Intramuscular injection of an aqueous flumethasone preparation (13.5 micrograms/kg body wt) produced drug residues in milk in the range of 0.7-1.2 ng/mL 12 h after treatment, whereas flumethasone was below the detection limit of 0.23 ng/mL 2 days after administration. These results indicate that toxicologically significant residues may arise transiently in the milk during the first 2-3 days after intramuscular injection of synthetic glucocorticoids. Urine from the same animals contained 5- to 50-fold higher glucocorticoid concentrations than the corresponding milk samples. Thus, urine analysis appears to be an effective method to monitor the use of synthetic glucocorticoids in food producing animals.

Rapid determination of O- and P-cresol isomers in urine from workers exposed to toluene by high-performance liquid chromatography using a graphitized carbon column

A simple and rapid procedure is described that permits the simultaneous determination of o- and p-cresol in urine of workers of other individuals exposed to toluene. The urine samples are enzymatically hydrolysed and analysed by high-performance liquid-chromatography with a detection limit of 0.2 mg/L, one fifth of the biological threshold limit value for o-cresol (1 mg/g), a specific marker of toluene exposure. A graphitized carbon column Hybercarb-S, that exhibits an excellent selectivity for aromatic positional isomers, was used with 1% phosphoric acid-acetonitrile (70:30, v/v) as mobile phase and a detection wavelength of 271 nm. The overall accuracy for o-cresol determination was 4.5% at 5 mg/L and 8% at 0.5 mg/L. The cresol isomers were sufficiently resolved from endogenous materials to avoid the need for any extraction step, and the method appears suitable for monitoring workers accurately under the permissible level of exposure for occupational medicine purpose.

The occurrence of ochratoxin A in coffee

Ochratoxin A (OA) is a nephrotoxic and nephrocarcinogenic mycotoxin which is predominantly produced by the two ubiquitous fungal genera, Aspergillus and Penicillium. OA is found in foodstuffs, predominantly in cereals but also in coffee beans. Inconsistent results have been published regarding the influence of roasting on the OA content in roasted beans and the transfer into the coffee brew. In the present study an HPLC method was used for the detection of OA in green and roasted coffee beans as well as in the coffee brew. For qualitative confirmation and quantification of low OA levels in roasted coffee beans and coffee brew an additional clean-up step by immunoaffinity column was applied before HPLC analysis. In green coffee beans OA was detected in 13 out of 25 commercial samples analysed (detection limit, 0.5 micrograms OA/kg). Roasting (250 degrees C, 150 sec) of naturally contaminated green beans or beans inoculated with A. ochraceus resulted only in a small reduction in the OA level. OA was also found to be eluted into the brew. Of 40 coffee brews prepared from commercially available samples OA was detected in 18 brews by HPLC and/or additional immunoaffinity column clean-up in the range of 0.4 to 7.8 micrograms OA/kg equivalent ground coffee. Our preliminary results suggest, therefore, that regular coffee consumption may contribute to exposure of humans to OA.

Cell-cycle and ploidy analysis in bone marrow and liver cells of rats after long-term consumption of irradiated wheat

Rats were fed for 4 or 90 days either with 70% freshly irradiated wheat (0.25, 0.75 or 2.25 kGy) and 30% complementary feed or with a control diet. None of the parameters examined (food consumption, body weight, haematological analysis, histopathological inspection of thymus, lung, liver, spleen and kidney, DNA analysis of bone marrow cells and nuclei from liver cells by flow cytometry) showed any statistically significant association with the feeding regimen. Minor changes in ploidy of liver cells and cell cycling of bone marrow cells were detectable (wheat-irradiation dose-dependent increase in G2/M-phase bone marrow cells up to 0.6%, decrease of 8C nuclei up to 1.1% in liver cells). From the pattern of alterations observed in our study, radiolytic by-products of wheat irradiation with a spindle poison-like activity can be excluded. Polyploid cells do not accumulate within the 90-day feeding period. The minor effects on cell cycle and ploidy observed are qualitatively comparable with the effects seen after food restriction in animal studies. It is suggested that an altered composition of fatty acids (the components of wheat most sensitive to irradiation) is responsible for these marginal effects. Our findings may explain the earlier findings of Bhaskaram and Sadasivan (American Journal of Clinical Nutrition 1975, 28, 130-135) who reported an increase in the number of polyploid cells in the lymphocytes of malnourished children fed irradiated wheat. The most likely mechanisms for such an effect are adaptive, constitutively regulated processes, similar to those which respond to food restriction. It is concluded that the consumption of irradiated wheat does not, therefore, pose any health risk to humans.

The relative importance of mutagens and carcinogens in the diet

Known mutagens and carcinogens in the diet were compiled and the risk of cancer was estimated on the basis of average exposure levels in Switzerland and carcinogenic potencies from rodent bioassays. The analysis showed that, except for alcohol, the sum of all known dietary carcinogens could only explain a few percent of the cancer deaths attributed by epidemiologists to dietary factors. The discrepancy was explained by a "carcinogenicity" of excess macronutrients. This hypothesis was based on an evaluation of dietary restriction experiments in rats and mice, where a dramatic reducing effect on spontaneous tumour formation was seen. From these experiments, a "carcinogenic potency" was deduced for food in excess (TD50 approximately 16 g/kg per day). Overnutrition in Switzerland was converted into excess food intake and the cancer risk estimated on the basis of the TD50 value. The resulting risk of 60,000 cases per one million lives would allow to explain by overnutrition almost all "diet-related" cancer deaths in humans.

Chemical carcinogens and overnutrition in diet-related cancer

The intake of known dietary carcinogens was compiled and the cancer risk was estimated on the basis of carcinogenic potencies in animals as derived from the Carcinogenic Potency Database by Gold and co-workers. The total cancer risk was compared with the number of cancer cases attributed by epidemiologists to dietary factors (one-third of all cancer cases, i.e. approximately 80,000 per one million lives). Except for alcohol, the known dietary carcinogens could not account for more than a few hundred cancer cases. This was seen both with the DNA-reactive carcinogens (heterocyclic aromatic amines, polycyclic aromatic hydrocarbons, N-nitroso compounds, estragole, aflatoxin B1, ethyl carbamate, to name the most important factors) as well as with those carcinogens which have not been shown to react with DNA (e.g. caffeic acid and the carcinogenic metals arsenic and cadmium). Residues and contaminants turned out to be negligible. Among the various possibilities to explain the discrepancy we investigated the role of overnutrition. Dietary restriction in animals is well known for its strong reducing effect on spontaneous tumor formation. These data can be used to derive a carcinogenic potency for excess macronutrients: the tumor incidence seen with the restricted animals is taken as a control value and the increased tumor incidence in the animals fed ad libitum is attributed to the additional feed intake. For excess standard diet in rats, a carcinogenic potency TD50 of 16 g/kg/day was deduced from a recent study. Overnutrition in Switzerland, estimated to be 5.5 kcal/kg/day, was converted to excess food (1.9 g/kg/day) and the cancer incidence was calculated. The result, 60,000 cancer cases per one million lives, is provocatively close to the number of cases not explained by the known dietary chemical carcinogens. Mechanistic studies will be required to test our hypothesis and investigate the role of different types of macronutrients in overnutrition.

The potential genotoxicity of sorbates: effects on cell cycle in vitro in V79 cells and somatic mutations in Drosophila

Sodium sorbate, potassium sorbate and an oxidation product of sodium sorbate, 4,5-epoxy-2-hexenoic acid, were tested for their genotoxic potential in cultured V79 Chinese hamster cells and in somatic cells of Drosophila melanogaster (wing spot test, SMART). In Drosophila only the epoxide showed a weak genotoxic effect. In V79 cells, freshly prepared sodium sorbate solutions at the highest concentrations only (2.5 mg/ml, 24 hr exposure) arrested mitosis at the G2/M cell cycle phase and potassium sorbate (2.5 mg/ml) had no effect. This arrest was reversible after a 24-hr recovery interval. Sodium sorbate solutions stored for up to 208 days were cytotoxic at 2.5 mg/ml, induced cell cycle arrest in the G2/M phase and increased cellular protein content, indicating an action similar to spindle poisoning and a chemical stress reaction (adaptation processes, modification of transcription). Potassium sorbate solutions stored for 28 days were also cytotoxic. With 4,5-epoxy-2-hexenoic acid at concentrations up to 0.01 mg/ml no effects were seen. At higher concentrations (at least 0.1 mg/ml) cell killing was observed, which probably resulted from unphysiologically lowered pH in the culture medium. Overall, the results are interpreted as an indication of a weak genotoxic potential of stored sodium sorbate solutions. Thus, sorbic acid and its potassium salt at the concentrations used for food preservation can still be considered as safe for human consumption.

Genotoxicity and cell transformation studies with sorbates in Syrian hamster embryo fibroblasts

Sorbic acid, sodium sorbate and potassium sorbate were tested for their genotoxic potential in the Syrian hamster embryo (SHE) fibroblast micronucleus assay and the SHE cell transformation test in vitro. Sorbic acid and potassium sorbate showed no activity in either test system. When freshly prepared sodium sorbate solutions were used, no genotoxic or cell-transforming activity was detected. However, sodium sorbate as stored solution, which previously had been heated and sonicated to facilitate solubilization, yielded a positive response in both test systems. It is concluded that oxidation products of sodium sorbate that possess genotoxic and cell-transforming properties are formed under conditions of heating, sonication and storage.

Lack of mutagenicity of ochratoxin A and B, citrinin, patulin and cnestine in Salmonella typhimurium TA102

The Aspergillus mycotoxins ochratoxin A and B, citrinin and patulin as well as combinations of ochratoxin A and citrinin did not induce reverse mutations in Salmonella typhimurium strain TA102. Therefore there is no indication for the induction of oxidative damage or crosslinks. The same is true for cnestine, a compound extracted from the plant Cnestis glabra.

Dietary intake and risk assessment of phototoxic furocoumarins in humans

The question of whether the furocoumarin content of vegetables is sufficient to induce phototoxic skin reactions after ultraviolet irradiation was examined in two experiments with four human volunteers. In a first experiment, 300 g of celery roots (total phototoxic furocoumarin content 28.2 micrograms/g) was ingested. No skin reactions were observed after UVA exposure (1.5-9 J/cm2), and the blood levels of the furocoumarins--psoralen, 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP)--were below the analytical detection limit of 2 ng/ml. To investigate the phototoxic effects of a mixture of the two most important furocoumarins in vegetables, after gastro-intestinal uptake, 8-MOP and 5-MOP (15 mg each) were ingested separately in a 50% alcoholic solution. A strong and persistent erythema was induced in three out of the four subjects (UVA dose: 3-25 J/cm2). The blood levels immediately before UVA irradiation varied between 14 and 114 ng/ml (8-MOP), and 17 and 70 ng/ml (5-MOP). In the subject who did not show phototoxicity, the blood levels remained at trace levels (3 ng/ml). Two subjects were also tested with a mixture of 10 mg 8-MOP plus 10 mg 5-MOP; in one subject the mixture induced pigmentation only, while in the other a mild-to-medium erythema was induced. The blood levels of the furocoumarins in the two subjects were similar (12-15 ng/ml for 8-MOP and 5-MOP). It is concluded that in humans the phototoxic threshold dose of furocoumarin mixtures is of the order of 10 mg 8-MOP plus 10 mg 5-MOP, which is equivalent to about 15 mg 8-MOP per person (blood levels of 8-MOP and 5-MOP at 30 min after ingestion of about 10-15 ng/ml each). This phototoxic threshold dose was not reached by the consumption of celery roots and other conventional vegetables under normal dietary habits (experimental intake of 2-8 mg per subject of the potentially phototoxic furocoumarin mixture). However, the safety factor between the possible actual intake of furocoumarins and the phototoxic threshold dose is about 2-10, which is relatively small.