Multispecies mass mortality in the Beagle Channel associated with paralytic shellfish toxins.

The Beagle Channel is a Subantarctic semi-estuarine environment at the southern tip of South America, where intoxication events associated with harmful algal blooms have been reported since 1886, including a world record in toxicity due to Alexandrium catenella in 1992. Toxic algae affect public health and ecosystem services, particularly mussel aquaculture and fisheries management. During the austral summer of 2022, an intense bloom of A. catenella (5 × 104 cells L-1) occurred in the Beagle Channel, leading to the second most toxic event in the area, with mussel toxicity reaching 197,266 µg STXeq kg-1. This event was synchronous with the mortality of marine organisms from different trophic levels and terrestrial fauna, i.e., two Fuegian red foxes and a southern caracara. Stomach content and liver samples from dead kelp gulls (Larus dominicanus), Magellanic penguins (Spheniscus magellanicus), papua penguins (Pygoscelis papua), and imperial cormorants (Leucocarbo atriceps), presented variable paralytic shellfish toxins (PST) levels (up to 3427 µg STXeq kg-1) as measured by high performance liquid chromatography (HPLC), suggesting that deaths were associated with high PST toxicity level. The different toxin profiles found in phytoplankton, zooplankton, squat lobsters (Grimothea gregaria), Fuegian sprat (Sprattus fuegensis), and seabirds evidenced possible toxin transformation along the food web and the possible transfer vectors. The unexpected detection of PST in terrestrial fauna (up to 2707 µg STXeq kg-1) suggested intoxication by scavenging on squat lobsters, which had high toxicity (26,663 µg STXeq kg-1). PST trace levels were also detected in a liver sample of a dead false killer whale (Pseudorca crassidens), an oceanic odontocete stranded on the coast during the bloom. Overall, our results denote the exceptional nature of the toxic, multispecies mortality event and that toxins may propagate to several levels of the food web in this Subantarctic environment.

The environmental performance of different pork production scenarios: a life cycle assessment study.

In order to evaluate the environmental performance generated by a "semi-technified" pig farm, as well as the comparison of different pig production scenarios, pig feed and animal production subsystems were evaluated considering both: (a) origin of feed ingredients and (b) variations in pig weight. Life cycle assessment methodology was used to evaluate the environmental performance, establishing 1 market pig as the functional unit (FU). Three ingredient origin distances (400, 950, and 1800 km) and three slaughter weights (110, 100, and 90 kg) were considered for the simulation analysis and comparison. The feed production subsystem was the main generator of environmental impacts, mainly caused by the cultivation of sorghum and the production of fat. The origin of the inputs represented the main increase in environmental impact for the feed production subsystem, mainly in the Fossil Depletion category, with a fivefold increase by acquiring inputs from 900 km and a ninefold increase at a distance of 1800 km. Producing lighter pigs resulted in the best environmental alternative, given the resultant 11% reduction in environmental impact.

The -174G/C and -572G/C interleukin 6 promoter gene polymorphisms in mexican patients with rheumatoid arthritis: a case-control study.

OBJECTIVE: There is a lack of information about the genotype frequencies of IL-6 -174G/C and -572G/C polymorphisms in Mexicans with rheumatoid arthritis (RA). Therefore, the aim of this study was to evaluate the association of the IL-6 -174G/C and -572G/C polymorphisms in Mexican mestizo with RA. METHODS: We included 137 patients with RA and 102 healthy controls. Patients were assessed for clinical characteristics. IL-6 -174G/C and -572G/C polymorphisms were genotyped using PCR-RFLP analysis. Allele and genotype frequencies and the Hardy-Weinberg equilibrium were computed. Odds ratios (ORs) were computed to identify the risk for RA associated with the presence of GG genotype in comparison with the GC or CC genotypes. RESULTS: The genotype -174GG occurred at a higher frequency in cases and controls (77.4% versus 78.4%, P = 0.845). We found similar results for the genotype -572GG (54% in patients versus 60.8% in controls, P = 0.295). CONCLUSIONS: This is the first study to evaluate the association of -174G/C and -572G/C polymorphisms of the IL-6 gene with RA in Mexican mestizo patients. These two polymorphisms were not associated with RA in the studied sample. Additional studies are required to evaluate if these IL-6 polymorphisms have relevance to the development of more severe disease.

Synthesis, characterization and electrochemical properties of iron-zirconia solid solution nanoparticles prepared using a sol-gel technique.

The range of compositions and temperatures at which single-phase tetragonal and monoclinic Fe-containing zirconia nanoparticles are stable is reported. Both types of iron-doped zirconia particles were synthesized by annealing dried gels FexZr1-xO2, with nominal compositions in the range 0 ≤ x ≤ 0.15, over the range of temperatures between 400 °C and 1300 °C. Monophasic crystalline specimens of Fe-ZrO2 solid solutions were characterized by different techniques including X-ray powder diffraction (XRD), infrared and Raman spectroscopies (IR and Raman), and transmission electron microscopy (TEM). Energy gaps were estimated from diffuse reflectance ultraviolet-visible spectra (DRUV-Vis) and compared with those obtained from electrochemical data. Upon increasing the amount of iron in both types of iron-containing zirconia-based structures the energy gaps slightly lowered. The electrochemical properties of those solid solutions obtained using the voltammetry of microparticles (VPM) technique indicated the presence of a small portion of iron as Fe(2+) in both types of crystalline Fe-doped ZrO2. Electrochemical data suggest that the monoclinic solid solutions provide a particularly high accessibility for promoting catalytic processes such as electrochemical oxygen reduction.

Prescription for antiresorptive therapy in Mexican patients with rheumatoid arthritis: is it time to reevaluate the strategies for osteoporosis prevention?

Glucocorticoids are frequently used in rheumatoid arthritis (RA) in order to alleviate symptoms of joint inflammation, retard erosions and to treat extra-articular manifestations, although these drugs may increase the risk of bone mineral loss and osteoporotic fractures. To date, in Mexico there are no studies that identify the frequency of patients with RA with corticosteroids, receiving therapy for osteoporosis. Therefore, we evaluated the prevalence and factors related to the prescription of antiresorptives in 520 Mexican patients with RA. We used a multivariate model to identify variables associated with antiresorptives prescription. We identified that although 79% of patients were under treatment with glucocorticoids, only 13% received antiresorptive agents as preventive therapy for osteoporosis. The multivariate analysis identified that higher proportions of antiresorptive drugs prescriptions were associated with female patients (OR 11.40, 95% CI: 1.5-84.3, P = 0.02), an age of 40 years or more (OR 3.22, 95% CI: 1.3-8.3, P = 0.02) and to consume a lower number of cointerventions with other drugs (OR 1.09, 95% CI: 1.0-1.2, P = 0.03). Corticosteroid treatment was not associated with the prescription of antiresorptives (P = 0.31). In conclusion, a low proportion of Mexicans with RA receive antiresorptive therapy independently regardless of whether they consume or not chronically corticosteroids. Additional strategies should be evaluated to encourage the prevention and early treatment for osteoporosis in patients with RA.

Ageing affects nitric oxide synthase, cyclooxygenase and oxidative stress enzymes expression differently in mesenteric resistance arteries.

1 Our aim was to study the role of nitric oxide (NO) and arachidonic acid pathways in the alpha(1)-adrenoceptor-mediated vasoconstriction in mesenteric resistance arteries from 3--4 and 22 to 23-month-old Sprague-Dawley rats. 2 The expression of NO synthase (NOS), cyclooxygenase (COX) isoforms, soluble guanylate cyclase, superoxide dismutase and the NAD(P)H oxidase subunits p22(phox) and p 47(phox) were determined. 3 The N(G)-nitro-l-arginine methyl ester, a non-selective NOS inhibitor, shifted to the left but indomethacin and NS 398, non-selective and selective COX-2 inhibitors, shifted to the right the concentration-response curve for the vasoconstriction by phenylephrine in both age groups. 4 Ageing up-regulated endothelial NOS and p22(phox) expression but did not modify COX, soluble guanylate cyclase, superoxide dismutase and p 47(phox) expression. 5 These data suggest that the observed enhancement of eNOS protein expression could constitute a compensatory mechanism to counter-regulate a chronic loss of NO possibly through increased superoxide anion production from NAD(P)H oxidase induced by age.

Manipulation of gold nanoparticles in liquid environments using scanning force microscopy

Precise and controlled manipulation of individual gold nanoparticles (deposited on a Si/SiO2 surface) in liquid environments using the tip of a scanning force microscope is reported for the first time. Experiments were performed in deionized water and in ethanol as a prototype for an organic solvent. Analysis of the amplitude signal of the cantilever before and during manipulation reveals that the particles are pushed across the surface, similar to the manipulation of nanoparticles in air.

Reactivity of indole derivatives towards oxygenated radicals.

The reactivity of a series of indole derivatives was assessed in the following systems: (i) oxidation of the indole derivatives induced by the thermolysis of 2,2'-azobis-(2-amidinopropane) (ABAP); (ii) oxidation of cumene induced by the thermolysis of 2,2'-azobis-(2-methyl propionitrile) (AIBN); (iii) lysozyme inactivation induced by the thermolysis of ABAP and (iv) brain homogenate autoxidation. In systems (ii) to (iv), addition of the indole derivatives decreases the rate of the process. The data obtained indicate that common factors (i.e., oxidation potential and presence of N-H bonds) control the reactivity of the indole derivatives in the four systems considered. However, in the brain homogenate autoxidation, hydrophobicity is an additional factor that affects the efficiency of antioxidants, as illustrated by Q1/2 values (the concentration of additive required to decrease the autoxidation rate to one half that observed in the absence of additive) of 0.1 mM and much greater than 8 mM for 3-methylindole and tryptophan, respectively.