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Póster presentado en Bérgamo (Italia), en junio de 2009.

Consumption of soy foods has been weakly associated with reduced colon cancer risk. Colon cancer risk is influenced by estrogen exposure, although the mechanism through which this occurs is not defined. Conversion of estradiol (E2) to estrone (E1) may be protective in the colon. We hypothesized that dietary phytoestrogens, or E1, would reduce colon tumorigenesis via an estrogen receptor (ER)-dependent mechanism. Ovariectomized ERαKO or wild-type (WT) female mice were fed diets containing casein (Casein), soy protein without isoflavones (Soy-IF), soy protein + genistein (Soy+Gen), soy protein + NovaSoy (Soy+NSoy) or soy protein + estrone (Soy+E1) from weaning. Colon tumors were induced with azoxymethane. Tumor incidence was affected by diet but not genotype. Colon tumor incidence was lower in ERαKO and WT mice fed the Soy+E1 diet compared with those fed the casein or Soy-IF diets. Mice fed Soy+NSoy had a lower tumor incidence than mice fed casein, but not Soy-IF. Genistein did not affect tumor incidence. Soy protein, independently of phytoestrogens or E1, significantly reduced relative colon weight, tumor burden and multiplicity. Relative colon weight was lower (P = 0.008) in mice fed Soy+E1 than in the other soy-fed groups. Tumor incidence in this group was lower than in the casein and soy-IF-fed groups and tended to be lower than in the others (P = 0.020). Hence, soy protein and NSoy protect mice from colon cancer, and E1 further reduces colon tumorigenesis in mice, independently of ERα. 134 179 182 Cited By :64

Composites of two natural zeolites – clinoptilolite and phillipsite, and cationic surfactants (cetylpyridinium chloride and Arquad® 2HT-75) were tested for the removal of two emerging contaminants – ibuprofen and naproxen. For each zeolite-rich rock, two different modifications of the zeolitic surfaces were prepared (monolayer and bilayer surfactant coverage). The influence of the initial drug concentrations and contact time on adsorption of these drugs was followed in buffer solution. The Langmuir model showed the highest adsorption capacity for the composite characterized by a bilayered surfactant at the clinoptilolite surface: 19.7 mg/g and 16.1 mg/g for ibuprofen and naproxen, respectively. Also, to simulate real systems, drug adsorption isotherms were conducted in natural water (Grindstone creek water – Columbia, Missouri, USA) by using the best performing adsorbent; in this case, a slight decrease of drug adsorption was recorded. Kinetic runs were performed in distilled water as well as in the presence of ions such as sulfates and bicarbonates; also, in this case, the interfering agents defined an adsorption decrease for bilayer composites.

In this study, composites of the natural zeolites and cationic surfactants cetylpyridinium chloride and Arquad® 2HT-75 were used for removal of two emerging contaminants – diclofenac sodium and ketoprofen. Modifying a clinoptilolite- and a phillipsite-rich tuff, with surfactants with one or two hydrophobic tails, resulted in composites in monolayer and bilayer forms. The intention was to better evaluate interactions of composites with selected molecules. Starting materials and composites were characterized by ATR–FTIR and STA coupled with EGA. The adsorption capacities of the prepared sorbents were estimated by determination of adsorption isotherms and kinetic runs. Maximum adsorption capacity, obtained from the Langmuir model, showed that the best results were for the bilayer form of the composites up to 35 mg/g. Between the two surfactants, composites with cetylpyridinium chloride gave better results. Zeta potential measurements showed that the surfactants turned out to be unstable on the zeolite surface, the only exception being bilayers prepared using the two-tailed surfactant Arquad® 2HT-75. These results suggested possible applications of these composites for water treatment purposes.

In this study, organozeolites were prepared by treatment of the natural zeolites (clinoptilolite and phillipsite) with cetylpyridinium chloride (CP) equivalent to 50 and 100% of their external cation exchange capacities (ECEC). Organoclinoptilolites (ZCPs) and organophillipsites (PCPs) were characterized by FTIR spectroscopy, thermal analysis, determination of the point of zero charge and zeta potential. Adsorption of zearalenone (ZEN) by ZCPs and PCPs at pH 3 and 7 was investigated. Results showed that adsorption of ZEN increases with increasing amounts of CP at the zeolitic surfaces for both ZCPs and PCPs but the adsorption mechanism was different. Adsorption of ZEN by ZCPs followed a linear type of isotherm at pH 3 and 7 while ZEN adsorption by PCPs showed non linear (Langmuir and Freundlich) type of isotherm at both pH values. Different interactions between the ZEN molecule (or ion) and ZCPs and PCPs occurred: partition (linear isotherms) and adsorption in addition to partition (non linear isotherms), respectively. For the highest level of organic phase at the zeolitic surfaces, the maximum adsorbed amount of ZEN was 5.73 mg/g for organoclinoptilolite and 6.86 mg/g for organophillipsite at pH 3. Slightly higher adsorption: 6.98 mg/g for organoclinoptilolite and 7.54 mg/g for organophillipsite was achieved at pH 7. The results confirmed that CP ions at both zeolitic surfaces are responsible for ZEN adsorption and that organophillipsites are as effective in ZEN adsorption as organoclinoptilolites.