Biomedical subjects
Publications and source records attributed to F J Martín-Gil.
Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez's, the Prestige's spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens , a bacterium promising for bioremediation.
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OBJECTIVES: We have contributed to the Design Validation Protocol of the new Abbott AxSYM Testosterone assay with a study on reference values and methods comparison. DESIGN AND METHODS: For reference values a population of 45 women and 30 men was tested. In methods comparison, 132 samples for the AxSYM vs. ACS-180, and 30 for the AxSYM vs. Elecsys were used. Pearson and intraclass concordance coefficients and Passing-Bablock test were performed for overall group, men and women. RESULTS: Reference values were 0.9-3.1 (females) and 1.0-30.2 nmol/L (males). Globally, a good agreement between methods in both the AxSYM vs. ACS-180 (slope: 0.88, y-intercept: 0.67, r = 0.961) and the AxSYM vs. Elecsys (slope: 1.08, y-intercept: 0.31, r = 0.935) studies was found. Slightly worse results were observed for women. CONCLUSIONS: The reference range of testosterone by the AxSYM system matches with those published for other methods. An acceptable agreement between the AxSYM Testosterone assay and both a classical (ACS-180) and a more recent (Elecsys) methodology was observed.
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OBJECTIVE/HYPOTHESIS: The objective of this study was to evaluate the morphological and microchemical changes that affect sclerotic stapes in otospongiosis and van der Hoeve syndrome. METHODS: A scanning electron microscope equipped with an energy-dispersive x-ray analyzer was used in the experiments. RESULTS: In otosclerosis, focal lesions are poorly mineralized, with low calcium salt and reduced calcium-to-phosphorus (Ca/P) ratio (1.9:1). This finding correlates with a spongiotic type of lesion and indicates unstable mineralization with possible change from hydroxyapatite to calcium triphosphate. In van der Hoeve syndrome the presence of magnesium in stapes suggests osteoclastic function stimulation. The osteoclasts secrete many protons, causing an acidified microenvironment. Brushite is formed, and Ca/P ratio decreases in comparison with that of control patients (2.0:1 vs. 2.6:1).
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Vermillion has been shown to be useful in preserving human bones from 5000 years ago. Remarkably well-preserved human bones have been found in the dolmenic burial 'La Velilla' in Osorno (Palencia, Spain), carefully covered by pulverized cinnabar (vermillion) which ensured their preservation even in non-favorable climatic conditions. We believe the red powder was deliberately deposited for preservative use because no cinnabar mine is to be found within 160 km, because of the large amount (hundreds of kilograms) used, and because its composition, red mercuric sulphide, is similar to that of preparations used in technical embalming. This finding pushes back the data of the use of mercury ore for preservation by four millennia in South America, and by at least one millennium in the Old World. Chemical and thermal analyses of vermillion in La Velilla have demonstrated its great purity and shown that the cinnabar was pulverized and washed (but not heated), producing a bright red-orange tone.
Differential scanning calorimetry (DSC) was used to investigate the thermal stability and behaviour of the lipopolysaccharides (LPS) of the outer membrane of Gram-negative bacteria and their lipid portion. DSC curves of LPS show thermal features between 200 and 129 degrees C (depolymerization) and between -13 and -36 degrees C (cooling phase transition). Both effects were related to the relative strength of the linkage types in the O-chain structure and to their capacity for intermolecular hydrogen bonding. DSC curves of lipids A show endotherm peaks between 40 and 24 degrees C, around 15 degrees C and between -23 and -4 degrees C. Based on these effects, strong differences in thermal behaviour can be observed between that of Brucella and Vibrio cholerae on the one hand, and that of Escherichia coli and Shigella flexneri on the other. Fluidity of the acyl chains and lyotropism, which are important parameters in expression of biological activities, are discussed using the above data. To explain some properties, fluidity could be related to the temperature of the gel<==>liquid crystalline (beta<==>alpha) phase transition, which occurs at physiological temperature. Nevertheless, fluidity could be related to temperature of the previous thermal effect (between 6 and 20 degrees C), for which a softening or partial melting of the sample has been evidenced. The thermal effect measured between -23 degrees C and -4 degrees C indicates a greatly reduced water concentration of lipid A from Brucella, thus explaining its early fusion process and its activity by means of hydrophobic interactions.
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BACKGROUND: Practical applications to enhance the productivity of agriculture by using plants with improved resistance to pathogens are expected to increase in the near future. Although tomato has been widely investigated for breeding purposes, there have been no studies on tomato allergenicity after plant hormones treatments. METHODS: Prick by prick tests were carried out with different tomato samples (fruits grown under biological conditions without addition of chemical products, and treated with ethylene and salicylic acid) in eight patients with ages between 12 and 27 years who suffered from anaphylaxis episodes after eating raw tomatoes. An immunoblot experiment with the different tomato extracts was performed using sera from these eight patients and controls. RESULTS: The wheals obtained in prick tests were significantly higher with the extracts of tomato treated with ethylene and SAA (chi(2) = 31.3, p < 0.0001) and the patients who presented higher wheal diameters in skin tests were those who had more severe episodes of anaphylaxis. Neither the protein stain nor the IgE immunodetection patterns clearly varied between the untreated and the hormone-treated samples. CONCLUSIONS: In the case of anaphylaxis induced by tomato, the treatment with plant hormones induced a higher cutaneous response than with non-treated tomato, but the "in vitro" response was similar.
The present work constitutes an entirely novel contribution in the scope of microbiology and especially in taxonomy, introducing thermolysis curves as a rapid method of characterization of fungal polysaccharides and bacterial lipopolysaccharides. The thermal analysis techniques applied were thermogravimetry and derivative thermogravimetry (TG-DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Each thermogram of a sample is represented by one or a few temperatures and, in DSC, by complementary enthalpy data. The temperatures of the thermograms from structurally unknown polysaccharides are compared with those used as references, and thus, information on their composition, linkage types, and anomeric configuration can be deduced. The situation is more complicated for bacterial lipopolysaccharides, but in whatever mode, a structural estimation is always possible. In the course of the development and validation of the thermal method, structural findings on relative stabilities of linkage types (valuable in carbohydrate research) have been recognized and are therefore also described in this work.