Haematopoiesis radioprotection in Balb/c mice by an aqueous mycelium extract from the Basidiomycete Pleurotus ostreatus mushroom.

The study examined the radioprotective activity of an aqueous extract from Pleurotus ostreatus mycelium administered to Balb/c mice. Male mice were whole-body irradiated on day 0 ((60)Co, at 0.43 Gy/min) and divided into two groups. The extract was administered intraperitoneally to one group (100 mg/kg) on days - 10 to - 6 and - 2 to +1 with respect to the irradiation. The irradiated-control group was injected with saline solution; non-irradiated mice were used as negative controls. The radioprotective effect was evident by increases in bone marrow cellularity (5.1 × 10(6)/femur vs. 1.1 × 10(6)/femur in saline-control mice, p < 0.05), leucocyte counts (10.5 × 10(9)/L vs. 4.5 × 10(9)/L, p < 0.05), and spleen cellularity (11.2 × 10(7)/spleen vs. 6.2 × 10(7)/spleen, p < 0.05). The extract stimulated macrophage phagocytic activity as judged by a faster rate of carbon clearance in terms of absorbance ratios (1.62 vs. 2.01, p < 0.05). Therefore, this extract may be a candidate therapeutic agent with radioprotective activity for haematopoiesis damage, particularly to cells involved in immune function.

Sanitary Risks Connected to the Consumption of Infusion from Senna rotundifolia L. Contaminated with Lead and Cadmium in Cotonou (Benin).

This study carried out an assessment of sanitary risks connected to the consumption of Senna rotundifolia Linn. contaminated with lead and cadmium. This plant was collected and analyzed by atomic absorption spectrophotometry. The results revealed a contamination of plants from markets of Dantokpa, Vossa, and Godomey with heavy metals. Senna from Vossa was higher in cadmium and lead levels (Pb: 2.733 mg/kg ± 0.356 mg/kg; Cd: 0.58 mg/kg ± 0.044 mg/kg) compared to the two other places (Pb: 1.825 mg/kg ± 0.133 mg/kg, Cd: 0.062 mg/kg ± 0.015 mg/kg and Pb: 1.902 mg/kg ± 0.265 mg/kg, Cd: 0.328 mg/kg ± 0.024 mg/kg), respectively, for Dantokpa and Godomey. In terms of risk assessment through the consumption of Senna, the values recorded for lead were nine times higher with children and six times higher with adults than the daily permissive intake (Pb: 3.376 × 10(-2) mg/kg/day for children and 2.105 × 10(-2) mg/kg/day for adults versus 3.6 × 10(-3) mg/kg/day for DPI). With respect to cadmium, there was no significant difference between the recorded values and the DPI (Cd: 1 × 14 10(-3) mg/ kg/day for children and Cd: 0.71 × 10(-3) mg/ kg/day for adults versus Cd: 1 × 10(-3) mg/kg/day for adults). This exposure of the population to lead and cadmium through the consumption of antimalarial healing plants could pose public health problems.

Bacterial-based additives for the production of artificial snow: what are the risks to human health?

For around two decades, artificial snow has been used by numerous winter sports resorts to ensure good snow cover at low altitude areas or more generally, to lengthen the skiing season. Biological additives derived from certain bacteria are regularly used to make artificial snow. However, the use of these additives has raised doubts concerning the potential impact on human health and the environment. In this context, the French health authorities have requested the French Agency for Environmental and Occupational Health Safety (Afsset) to assess the health risks resulting from the use of such additives. The health risk assessment was based on a review of the scientific literature, supplemented by professional consultations and expertise. Biological or chemical hazards from additives derived from the ice nucleation active bacterium Pseudomonas syringae were characterised. Potential health hazards to humans were considered in terms of infectious, toxic and allergenic capacities with respect to human populations liable to be exposed and the means of possible exposure. Taking into account these data, a qualitative risk assessment was carried out, according to four exposure scenarios, involving the different populations exposed, and the conditions and routes of exposure. It was concluded that certain health risks can exist for specific categories of professional workers (mainly snowmakers during additive mixing and dilution tank cleaning steps, with risks estimated to be negligible to low if workers comply with safety precautions). P. syringae does not present any pathogenic capacity to humans and that the level of its endotoxins found in artificial snow do not represent a danger beyond that of exposure to P. syringae endotoxins naturally present in snow. However, the risk of possible allergy in some particularly sensitive individuals cannot be excluded. Another important conclusion of this study concerns use of poor microbiological water quality to make artificial snow.

Domoic acid induces direct DNA damage and apoptosis in Caco-2 cells: recent advances.

Domoic acid (DA) is a neurotoxin produced by sea-water phytoplankton. Shellfish feeding on the phytoplankton can bioconcentrate DA, leading to a potentially serious health hazard for people consuming the contaminated shellfish. DA is the principal toxin responsible for amnesic shellfish poisoning (ASP). The toxic mechanism of DA is believed to be mediated at the level of the mitochondria, where uncoupling of oxidative phosphorylation decreases membrane permeability, causing cell swelling and ultimately lysis. Literature is poor concerning data on the possible genotoxicity and cytotoxicity of DA. In the present study, we have evaluated the cytotoxicity and genotoxicity of DA on a human colorectal adenocarcinoma cell line (Caco-2). Our results clearly demonstrate that DA decreased cell viability (IC(50) about 70 ng/mL), induced direct DNA damage from 15 ng/mL, and apoptosis in Caco-2 cells at 100 ng/mL. This apoptosis is likely bax-dependent and occurred only at high concentrations of DA, while lower concentrations upregulated both bax and bcl-2 at an apparent constant ratio until a sudden decrease of bcl-2 at 100 ng/mL and increase of bax.

Cytogenetic analysis of tannery workers in Morocco.

This study investigated the possible genetic effects in blood lymphocytes of tannery workers from Morocco being professionally exposed to multiple chemical agents. It was shown that the frequencies of cells with chromosome aberrations and micronuclei were significantly increased in the lymphocytes of the workers compared with the frequencies found in an unexposed control population.

Anticancer effect of a new benzophenanthridine isolated from Zanthoxylum madagascariense (Rutaceline).

Fractionation of the cyclohexane extract from the stem bark powder of Zanthoxylum madagascariense led to the isolation of a new benzophenanthridine-type alkaloid, hydrochloride of 2,3-methylendioxy-8-hydroxy- 7-methoxy-benzo[C]phenanthridine (Rutaceline), characterized on the basis of its spectral data. Rutaceline was evaluated for its antiproliferative capacity on the human colorectal adenocarcinoma (Caco-2) and the African green monkey kidney (Vero) cell lines. The 50% inhibition of cell growth (IC50) obtained after 24 h incubation was similar for both cells lines (110-115 microg/ml, i.e. 269-281 microM), but at 48 h the IC50 value for the Caco-2 cells was lower than for the Vero cells (20 microg/lml, i.e. 49 microM versus 90 microg/ml, i.e. 220 microM) indicating a higher cell growth inhibitory effect on the colon adenocarcinoma cells. At the respective IC50 concentrations, Rutaceline did not significantly induce apoptosis but induced cell cycle arrest in the GO/G1 phase, as well as a decrease of cells in S phase. Rutaceline also induced DNA fragmentation in both cell lines, as revealed by agarose gel electrophoresis, and a dose-dependent clastogenic effect in both cell lines as revealed by the Comet assay.

Co-occurrence of aflatoxin B1, fumonisin B1, ochratoxin A and zearalenone in cereals and peanuts from Côte d'Ivoire.

This survey examined 30 samples of rice (n = 10), maize (n = 10) and peanuts (n = 10) from Côte d'Ivoire for aflatoxin B1, fumonisin B1 and zearalenone using immunoassays, and ochratoxin A using a validated HPLC method with fluorescence detection. In Côte d'Ivoire, as in other countries, several mycotoxins are present in the same commodities. These mycotoxins are from different structural families: aflatoxin B1, fumonisin B1, zearalenone and ochratoxin A, normally produced by fungal species from Aspergillus, Penicillium and Fusarium genera. Some samples contained four mycotoxins (86%). Four peanuts samples did not show ochratoxin A (14%), whereas they contained aflatoxin B1 concentrations above the EU regulatory limits. Concentrations of ochratoxin A, zearalenone and fumonisin B1 were low and may not cause problems per se; however, fears remain that the tolerable daily intake may be exceeded due to eating habits and synergistic effects could be important with the combination of several mycotoxins. Investigations in this direction are underway, together with isolation and characterization of the fungal species involved.

Preliminary survey of ochratoxin A in millet, maize, rice and peanuts in Côte d'Ivoire from 1998 to 2002.

In a preliminary study, samples of millet (n =33) maize (n=41), rice (n=10) and peanuts (n=10) from Côte d'Ivoire were analysed for ochratoxin A (OTA) by HPLC with fluorimetric detection, followed by confirmation by cleavage of the OTA molecule using carboxypeptidase with HPLC separation and fluorimetric quantification of the released ochratoxin alpha (OTh). With the exception of four samples of peanuts, all samples showed OTA contamination, ranging from 3 to 1738 microg/kg. All cereals were contaminated and the OTA concentrations were in the range of 17-204 microg/kg for millet, 3-1738 microg/kg for maize, 9-92 microg/kg for rice and 0.6-64 microg/kg for peanuts, depending on the year of harvest. Most of the samples would not be accepted according to the EU regulatory limits for this mycotoxin. Following this survey, research for other mycotoxins and the evaluation of the exposure of the population is underway.

Comparative study of cytotoxicity and oxidative stress induced by deoxynivalenol, zearalenone or fumonisin B1 in human intestinal cell line Caco-2.

Fusarium species infestations of cereals crops occur worldwide. Fusarium toxins such as, deoxynivalenol (DON), zearalenone (ZEN) and fumonisin B1 (FB1) have been shown to cause diverse toxic effects in animals and also suspected of disease causation in humans. From the literature and mechanistic point of view, DON binds to the ribosomal peptidyl-transferase and inhibits protein synthesis specifically and DNA synthesis consequently. ZEN known to be genotoxic, binds to 17-beta-estradiol receptors, induces lipid peroxidation, cell death and inhibits protein and DNA synthesis. FB1 disrupts sphingolipid metabolism, induces lipid peroxidation altering the cell membrane and causing cell death. We intended to compare DON, ZEN and FB1 (1-150 microM) cytotoxic effect and the pathways leading to cell death and related to oxidative stress and macromolecules syntheses in a human intestinal cell line in order to tentatively classify them according to their respective potential toxicity. The comparison reveals that all three mycotoxins bear, at variable degree, the capability of inducing lipid peroxidation (MDA production) and could be classified above 10 microM in decreasing potency order FB1>DON>ZEN. This effect seems to be related to their common target that is the mitochondria as revealed by MTT test and seemingly not related to sphingoids accumulation concerning FB1. DON and ZEN also adversely affect lysosomes in contrast to FB1. The three mycotoxins inhibit protein synthesis with respective IC50 of 5, 8.8 and 19 microM for DON, FB1 and ZEN confirming that protein synthesis is a specific target of DON. DNA synthesis is inhibited by DON, ZEN and FB1 with respective IC50 of 1.7, 10 and 20 microM. However at higher concentrations DNA synthesis seems to be restored for FB1 and DON suggesting a promoter activity. Altogether the potency of the three mycotoxins in macromolecules inhibition is DON>ZEN>FB1 in Caco-2 cells. It appears then that FB1 acts rather through lipid peroxidation while DON affects rather DNA and protein synthesis.