Processed Meat and Colorectal Cancer: A Review of Epidemiologic and Experimental Evidence

Processed meat intake may be involved in the etiology of colorectal cancer, a major cause of death in affluent countries. The epidemiologic studies published to date conclude that the excess risk in the highest category of processed meat-eaters is comprised between 20 and 50% compared with non-eaters. In addition, the excess risk per gram of intake is clearly higher than that of fresh red meat. Several hypotheses, which are mainly based on studies carried out on red meat, may explain why processed meat intake is linked to cancer risk. Those that have been tested experimentally are (i) that high-fat diets could promote carcinogenesis via insulin resistance or fecal bile acids; (ii) that cooking meat at a high temperature forms carcinogenic heterocyclic amines and polycyclic aromatic hydrocarbons; (iii) that carcinogenic N-nitroso compounds are formed in meat and endogenously; (iv) that heme iron in red meat can promote carcinogenesis because it increases cell proliferation in the mucosa, through lipoperoxidation and/or cytotoxicity of fecal water. Nitrosation might increase the toxicity of heme in cured products. Solving this puzzle is a challenge that would permit to reduce cancer load by changing the processes rather than by banning processed meat

Beef meat promotion of dimethylhydrazine-induced colorectal carcinogenesis biomarkers is suppressed by dietary calcium

Red meat consumption is associated with increased risk of colorectal cancer. We have previously shown that haemin, Hb and red meat promote carcinogen-induced preneoplastic lesions: aberrant crypt foci (ACF) and mucin-depleted foci (MDF) in rats. We have also shown that dietary calcium, antioxidant mix and olive oil inhibit haemin-induced ACF promotion, and normalize faecal lipoperoxides and cytotoxicity. Here we tested if these strategies are effective also against red meat promotion in dimethylhydrazine-induced rats. Three diets with 60% beef meat were supplemented with calcium phosphate (33 g/kg), antioxidant agents (rutin and butylated hydroxyanisole, 0•05% each) and olive oil (5 %). ACF, MDF, faecal water cytotoxicity, thiobarbituric acid reactive substances (TBARS) and urinary 1,4-dihydroxynonane mercapturic acid (DHN-MA) were measured. Beef meat diet increased the number of ACF (þ30 %) and MDF (þ100 %) (P,0•001), which confirms our previous findings. Promotion was associated with increased faecal water TBARs ( £ 4) and cytotoxicity ( £ 2), and urinary DHN-MA excretion ( £ 15). Calcium fully inhibited beef meat-induced ACF and MDF promotion, and normalized faecal TBARS and cytotoxicity, but did not reduce urinary DHN-MA. Unexpectedly, high-calcium control diet-fed rats had more MDF and ACF in the colon than low-calcium control diet-fed rats. Antioxidant mix and olive oil did not normalize beef meat promotion nor biochemical factors. The results confirm that haem causes promotion of colon carcinogenesis by red meat. They suggest that calcium can reduce colorectal cancer risk in meat-eaters. The results support the concept that toxicity associated with the excess of a useful nutrient may be prevented by another nutrient

Characterization and digital restauration of XIV-XV centuries written parchments by means of non-destructive techniques. Three case studies

Parchment is the primary writing medium of the majority of documents with cultural importance. Unfortunately, this material suffers of several mechanisms of degradation that affect its chemical-physical structure and the readability of text. Due to the unique and delicate character of these objects, the use of nondestructive techniques is mandatory. In this work, three partially degraded handwritten parchments dating back to the XIV-XV centuries were analyzed by means of X-ray fluorescence spectroscopy, µ-ATR Fourier transform infrared spectroscopy, and reflectance and UV-induced fluorescence spectroscopy. 'e elemental and molecular results provided the identification of the inks, pigments, and superficial treatments. In particular, all manuscripts have been written with iron gall inks, while the capital letters have been realized with cinnabar and azurite. Furthermore, multispectral UV fluorescence imaging and multispectral VIS-NIR imaging proved to be a good approach for the digital restoration of manuscripts that suffer from the loss of inked areas or from the presence of brown spotting. Indeed, using ultraviolet radiation and collecting the images at different spectral ranges is possible to enhance the readability of the text, while by illuminating with visible light and by collecting the images at longer wavelengths, the hiding effect of brown spots can be attenuated

Characterization and digital restauration of XIV-XV centuries written parchments by means of non-destructive techniques. Three case studies

Parchment is the primary writing medium of the majority of documents with cultural importance. Unfortunately, this material suffers of several mechanisms of degradation that affect its chemical-physical structure and the readability of text. Due to the unique and delicate character of these objects, the use of nondestructive techniques is mandatory. In this work, three partially degraded handwritten parchments dating back to the XIV-XV centuries were analyzed by means of X-ray fluorescence spectroscopy, µ-ATR Fourier transform infrared spectroscopy, and reflectance and UV-induced fluorescence spectroscopy. 'e elemental and molecular results provided the identification of the inks, pigments, and superficial treatments. In particular, all manuscripts have been written with iron gall inks, while the capital letters have been realized with cinnabar and azurite. Furthermore, multispectral UV fluorescence imaging and multispectral VIS-NIR imaging proved to be a good approach for the digital restoration of manuscripts that suffer from the loss of inked areas or from the presence of brown spotting. Indeed, using ultraviolet radiation and collecting the images at different spectral ranges is possible to enhance the readability of the text, while by illuminating with visible light and by collecting the images at longer wavelengths, the hiding effect of brown spots can be attenuated

A Cation-π Interaction Discriminates among Sodium Channels That Are Either Sensitive or Resistant to Tetrodotoxin Block

Voltage-gated sodium channels control the upstroke of the action potential in excitable cells of nerve and muscle tissue, making them ideal targets for exogenous toxins that aim to squelch electrical excitability. One such toxin, tetrodotoxin (TTX), blocks sodium channels with nanomolar affinity only when an aromatic Phe or Tyr residue is present at a specific location in the external vestibule of the ion-conducting pore. To test whether TTX is attracted to Tyr401 of NaV1.4 through a cation-{pi} interaction, this aromatic residue was replaced with fluorinated derivatives of Phe using in vivo nonsense suppression. Consistent with a cation-{pi} interaction, increased fluorination of Phe401, which reduces the negative electrostatic potential on the aromatic face, caused a monotonic increase in the inhibitory constant for block. Trifluorination of the aromatic ring decreased TTX affinity by ~50-fold, a reduction similar to that caused by replacement with the comparably hydrophobic residue Leu. Furthermore, we show that an energetically equivalent cation-{pi} interaction underlies both use-dependent and tonic block by TTX. Our results are supported by high level ab initio quantum mechanical calculations applied to a model of TTX binding to benzene. Our analysis suggests that the aromatic side chain faces the permeation pathway where it orients TTX optimally and interacts with permeant ions. These results are the first of their kind to show the incorporation of unnatural amino acids into a voltage-gated sodium channel and demonstrate that a cation-{pi} interaction is responsible for the obligate nature of an aromatic at this position in TTX-sensitive sodium channels

Low frequency geomagnetic field fluctuations at cap and low latitude during October 29-31, 2003

On October-November 2003 complex interplanetary structures, originated by a series of solar eruptions, hit the Earth, triggering violent Sun-Earth connection events. In this paper we analyze the low frequency geomagnetic field fluctuations detected on the ground during Oct. 29-31, 2003, a time period characterized by extremely high solar wind speed values and by out-of-ecliptic interplanetary magnetic field orientation for intervals of several hours. We analyze geomagnetic field measurements at four high latitude stations located in the polar cap, three in the southern and one in the northern hemisphere. From a comparison with simultaneous measurements at low latitude, we address the question of the global character of the observed phenomena. The results show, for selected time intervals, the occurrence of simultaneous fluctuations at all the stations, with high coherence even between high and low latitude; it is interesting that these fluctuations are detected during open magnetospheric conditions, when the high latitude stations are situated well within the polar cap, i.e. far from closed field lines

Improved photocatalytic properties of doped titanium-based nanometric oxides

Photocatalysis is considered one of the most promising technologies for applications in the environmental field especially in the abatement of water-soluble organic pollutants. In this field, titanium dioxide nanoparticles have drawn much attention recently; however, the use of this oxide presents some limitation since it allows to obtain high photoresponse and degradation efficiency only under UV light irradiation, that represents the 3 to 4% of the solar radiation, so preventing its environmental large-scale applications under diffuse daylight. In this work the photocatalytic efficiencyoftitanium-based oxides systems containing alkaline earth metals such as barium and strontium, prepared by a simple sol-gel method was investigated, evaluating the degradation of methylene blue as model compound under UV and visible light irradiation. The results were compared with those obtained with Degussa P25 titanium dioxide. The achieved degradation percentage of methylene blue are very promising showing that under visible light irradiation it is possible to obtain a maximum dye removal percentage ~ 50 % higher than that obtained with the Degussa P25

The Earth’s passage of coronal mass ejecta on October 29-31, 2003: ULF geomagnetic field fluttuations at very high latitude

We study ULF geomagnetic field fluctuations detected on October 29-31, 2003, when the Earth’s arrival of solar wind CMEs produced major geomagnetic storms; these solar wind structures are characterized by extremely high plasma speed and long-duration intervals with northward interplanetary magnetic field. The analyzed geomagnetic field data are from four high latitude stations (three in Antarctica), located deep in the polar cap. The analysis is extended also to low latitude European stations, in order to discriminate between local and global magnetospheric phenomena