Papers by Alejandro Martinez
Brain Research, 2020
Background: Activating point mutations of GNAS at codon 201 have been detected in approximately t... more Background: Activating point mutations of GNAS at codon 201 have been detected in approximately two thirds of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. Intraductal papillary neoplasms of the bile ducts (IPNBs) morphologically resemble pancreatic IPMNs. This study sought to assess the mutational status of GNAS at codon 201 in IPNBs. Methods: Thirty-four patients were included. DNA from microdissected IPNBs was subjected to a polymerase chain reaction and ligation method for the detection of GNAS mutations at codon 201 and of KRAS mutations at codon 12. Mutational status was compared with clinical and pathologic data. Results: The IPNBs had a median diameter of 3.5 cm and were located intrahepatically (n = 6), extrahepatically (n = 13), both intra-and extrahepatically (n = 4) or in the gallbladder (intracystic papillary neoplasms, n = 11). Most exhibited pancreatobiliary differentiation (n = 20), high-grade dysplasia (n = 26) and an associated adenocarcinoma (n = 20). Analysis of GNAS codon 201 identified only one mutant sample in a multifocal intestinal subtype intrahepatic IPNB with high-grade dysplasia. Six lesions harboured a KRAS codon 12 mutation. Conclusions: GNAS codon 201 mutations are uncommon in IPNBs, by contrast with pancreatic IPMNs. More comprehensive molecular profiling is needed to uncover the pathways involved in IPNB development.
1. En la presente memoria doctoral se purifico la 5'-nt mediante la extraccion secuencial del... more 1. En la presente memoria doctoral se purifico la 5'-nt mediante la extraccion secuencial del musculo esqueletico de raton. Se obtuvo una fraccion soluble rica en actividad ampasa. 2. Luego se purifico la 5'-nt del extracto, obteniendose tres preparaciones: nr=ampasa no retenida en la matriz con & nt-i= enzima eluida con beta gp; nt-ii = ampasa ligada a la matriz y liberada con amp. 3. La enzima se ha purificado unas 200 veces en nt-i, y 7800 en nt-ii. 4. Nt-ii reacciona con anticuerpos generados contra la ent de plasma seminal bovino. Las subunidades de 5'-nt de musculo presentan masas moleculares de 74, 65 y 52 kda. 5. La actividad ampasa es 5'-nucleotidasa, como lo demuestra su caracter glicoproteico, afinidad por amp, inhibicion por alfa, beta-metilenadenosina- 5'-difosfato, e interaccion con anticuerpos. 6. Los valores de los coeficientes de sedimentacion de las formas enzimaticas y su variacion con el detergente anadido al gradiente indican que la fraccion ...
Environmental Technology, 2020
Functionalized magnetite nanoparticles with Moringa oleifera with potent antibacterial action in ... more Functionalized magnetite nanoparticles with Moringa oleifera with potent antibacterial action in wastewater Contaminations by Staphylococcus aureus in food industry environments have been extended to industrial Effluent Treatment Plant (ETP).The methodologies used in ETP for bacterial removals andquality parametersadjustmentcommonly use products toxic to the environment, being mostly inefficient against virulent bacteria such as S. aureus. Seeds of Moringa oleifera Lam. (MO) have potential to be used in ETPas an alternative to harmful products, as it has both the ability to regulate the physicochemical parameters of water and has antibacterial action.Functionalization of MO with magnetite magnetic nanoparticles(Fe3O4) at nanoscale focusing on coagulation and flocculation of wastewater has been gaining prominence. Therefore, the present study evaluated the potential use of the magnetic coagulant MO-Fe3O4 in the elimination of S. aureus in synthetic dairy effluent; concomitantly sought to adjust thequalitylevelsof physicochemical parameters. MO-Fe3O4 added to synthetic dairy effluent at different concentrations amounted to 16 treatments, which were evaluated for removal of color, turbidity, UV254nm and S. aureus on the effluent surface and sludge after 30 min of sedimentation. The results confirmed the efficient elimination of S. aureus simultaneously with a significant reductionof the physicochemical values, with constant efficiency up to 30 min. Scanning electron microscopy images confirm the removal of S. aureus on the effluent surface and sludge. Thus, this study was able to present a natural coagulant capable of removebacteria and adjust the quality levels of the effluentafter 10 min of sedimentation, making this biotechnological innovation highly applicable to ETP.
Biotecnia, 2018
Vivimos una época que experimenta un crecimiento acelerado de la población y una fuerte industria... more Vivimos una época que experimenta un crecimiento acelerado de la población y una fuerte industrialización. La humanidad, en el afán de satisfacer sus múltiples necesidades, se ha supeditado tanto a tecnologías que dañan el medio ambiente como a la dependencia de compuestos xenobióticos. En consecuencia, serios problemas de contaminación que amenazan tanto la salud de los seres vivos como del ambiente se han suscitado. Como respuesta, la biotecnología ambiental a través de la biorremediación como una de sus aplicaciones, desempeña un rol clave en la remoción de contaminantes. Diferentes sistemas biológicos de remediación, que incluyen el uso de plantas, algas, bacterias y hongos, se han empleado con éxito para tratar ambientes contaminados de metales pesados, hidrocarburos, compuestos xenobióticos, y elementos radioactivos. Aunque la biorremediación no es una tecnología nueva, esta ha ido evolucionando y se ha posicionado como un factor sustancial, tanto en términos de eficiencia com...
Langmuir, 2020
Molecular information on the potential of europium complexes for local recognition of a nucleosid... more Molecular information on the potential of europium complexes for local recognition of a nucleoside-based drug by using nanostructured interfaces assembled as Langmuir-Blodgett films
Oxidative Medicine and Cellular Longevity, 2016
The protective effect of different polyphenols, catechin (Cat), quercetin (Qc) (flavonoids), gall... more The protective effect of different polyphenols, catechin (Cat), quercetin (Qc) (flavonoids), gallic acid (GA), caffeic acid (CfA), chlorogenic acid (ChA) (phenolic acids), and capsaicin (Cap), against H2O2-induced oxidative stress was evaluated in rat enterocytes using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy and Fourier Transform Infrared Microspectroscopy (FTIRM), and results were compared to standard lipid peroxidation techniques: conjugated dienes (CD) and Thiobarbituric Acid Reactive Substances (TBARS). Analysis of ATR-FTIR and FTIRM spectral data allowed the simultaneous evaluation of the effects of H2O2and polyphenols on lipid and protein oxidation. All polyphenols showed a protective effect against H2O2-induced oxidative stress in enterocytes, when administered before or after H2O2. Cat and capsaicin showed the highest protective effect, while phenolic acids had weaker effects and Qc presented a mild prooxidative effect (IR spectral pro...
Protein & Peptide Letters, 2016
Sulfur (S) is an essential macronutrient for all living organisms. A variety of organic and inorg... more Sulfur (S) is an essential macronutrient for all living organisms. A variety of organic and inorganic S species with oxidation states ranging from -2 to +6 exist. Today few spectroscopic and biochemical methods are used to investigate sulfur oxidation state and reactivity in biological samples. X-ray absorption near edge spectroscopy (XANES) is a very well suited spectroscopic technique to probe the oxidation state and the surrounding chemical environment of sulfur. Microspectroscopy beamlines, operating at almost all synchrotron facilities, allow the combination of XANES with X-ray fluorescence mapping (µXRF). Using this approach distribution maps of S in complex biological samples (intact parts of tissue, or individual cells) can be obtained using µXRF and its oxidation state can be probed in-situ (µXANES). Moreover, µXRF mapping at specific energies enables for chemical contrast of S at different oxidation states without the need of staining chemicals. This review introduces the basic concepts of synchrotron µXRF and µXANES and discusses the most recent applications in life science. Important methodological and technical issues will be discussed and results obtained in different complex biological samples will be presented.
Molecular and Cellular Biochemistry, 2015
The incidence of anxiety-related diseases is increasing these days, hence there is a need to unde... more The incidence of anxiety-related diseases is increasing these days, hence there is a need to understand the mechanisms that underlie its nature and consequences. It is known that limbic structures, mainly the prefrontal cortex and amygdala, are involved in the processing of anxiety, and that projections from prefrontal cortex and amygdala can induce activity of the hypothalamic-pituitary-adrenal axis with consequent cardiovascular changes, increase in oxygen consumption, and ROS production. The compensatory reaction can include increased antioxidant enzymes activities, overexpression of antioxidant enzymes, and genetic shifts that could include the activation of antioxidant genes. The main objective of this study was to evaluate the oxidant/antioxidant effect that chronic anxiogenic stress exposure can have in prefrontal cortex, amygdala, and hypothalamus by exposition to predator odor. Results showed (a) sensitization of the HPA axis response, (b) an enzymatic phase 1 and 2 antioxidant response to oxidative stress in amygdala, (c) an antioxidant stability without elevation of oxidative markers in prefrontal cortex, (d) an elevation in phase 1 antioxidant response in hypothalamus. Chronic exposure to predator odor has an impact in the metabolic REDOX state in amygdala, prefrontal cortex, and hypothalamus, with oxidative stress being prevalent in amygdala as this is the principal structure responsible for the management of anxiety.
Journal of venom research, 2014
The Northern black-tailed rattlesnake (Crotalus molossus molossus) venom is mainly hemotoxic, hem... more The Northern black-tailed rattlesnake (Crotalus molossus molossus) venom is mainly hemotoxic, hemorrhagic, and neurotoxic. Its effects in the central nervous system are unknown and only poorly described for all Viperidae species in general. This is why we are interested in describe the damage induced by C. m. molossus venom in rat brain, particularly in the area postrema capillaries. Four C. m. molossus venom doses were tested (0.02, 0.05, 0.10 and 0.20mg/kg) injected intramuscularly at the lower limb, incubated by 24 hours and the brains were harvested. Area postrema coronal sections were stained with Haematoxylin and Eosin, and examined to observe the venom effect in quantity of capillaries and porphology. Starting from the 0.10mg/kg treatment we observed lysed extravasated erythrocytes and also capillary breakdown, as a consequence of hemorrhages appearance. The number of capillaries decreased significantly in response to the venom dose increment. Hemorrhages could be caused by t...
Neuroimmunomodulation, 2015
Background: Chronic psychological distress can cause neuroinflammation, but the involvement of le... more Background: Chronic psychological distress can cause neuroinflammation, but the involvement of leukocytes in this inflammatory response remains unclear. The area postrema (AP) is considered a neural-immune interface because it lacks a blood-brain barrier and a site for leukocyte recruitment in neuroinflammatory conditions induced by immunological insults, but its role in chronic psychological distress has not been explored. Objective: To determine leukocyte recruitment to the AP after chronic psychological distress. Methods: Rats were exposed to cat odor for 5 consecutive days to induce distress, and, on the 6th day, their brains were dissected to perform immunohistofluorescence studies of the AP. Immune cells were identified and quantified with CD45 and CD11b markers. The distribution of neurons and immune cells was determined using TrkA and CD45 markers, respectively. Results: Distress induced a significant increase in CD45+ and CD11b+ cells in the AP. Three immunophenotypes were ...
Conditions of stress can originate from diverse stimuli including physical, chemical, antigenic a... more Conditions of stress can originate from diverse stimuli including physical, chemical, antigenic and psychological. The latter is processed in part via the hypothalamic pituitary adrenal (HPA) axis, with input from and communication between the amygdala (AM) and prefrontal cortex (PFC). The HPA axis generates an increase in circulating glucocorticoids, augmenting metabolism and, consequently, oxygen consumption, increasing the production of free radicals and reactive oxygen species (ROS). Exposure to predator odor as a model of non invasive acute stress was used to evaluate the hypothesis that psychogenic stress can modify enzymatic antioxidant responses. The activities of various enzymes, catalase (CAT), cytosolic and mitochon drial superoxide dismutase (Cu, Zn SOD and Mn SOD, respectively) and glutathione S transferase (GST), were determined in AM and PFC. Acute psychogenic stress inhibited CAT activity in the AM and PFC, and increased Mn SOD activity in the PFC. These results demonstrate that different responses can be elicited by the same stressor in two separate brain regions involved in processing emotional stimuli, and that changes in specific antioxidant enzymatic responses can be seen with exposure to acute psychogenic stress.
Plant Physiology and Biochemistry, 2009
The effect of cadmium (Cd) on both the absorption of important nutrients and the synthesis of low... more The effect of cadmium (Cd) on both the absorption of important nutrients and the synthesis of low molecular weight thiols (LMWTs) was investigated in corn plants. The inductively coupled plasmaoptical emission spectroscopy results demonstrated that the concentration of Cd in tissues (mainly in roots) increased as the concentration in the medium increased. In addition, the concentration of phosphorus increased in roots of Cd treated plants but remained at normal concentration in shoots. On the other hand, the uptake of sulfur (S) followed a similar trend as the Cd uptake. The concentration of S and the production of LMWT were found to increase significantly upon exposure to Cd. The results of the X-ray absorption spectroscopy analyses indicated that Cd within tissues was bound to S ligands with interatomic distances of 2.51-2.52 Å. These results confirm a strong linkage between S uptake and the production of LMWT upon exposure to Cd.
Journal of Nanomaterials, 2014
Magnetic nanoparticles (MNPs) have great potential in biomedical applications because of their ma... more Magnetic nanoparticles (MNPs) have great potential in biomedical applications because of their magnetic response offers the possibility to direct them to specific areas and target biological entities. Magnetic separation of biomolecules is one of the most important applications of MNPs because their versatility in detecting cancer biomarkers. However, the effectiveness of this method depends on many factors, including the type of functionalization onto MNPs. Therefore, in this study, magnetite nanoparticles have been developed in order to separate the 5′-nucleotidase enzyme (5eNT). The 5eNT is used as a bio-indicator for diagnosing diseases such as hepatic ischaemia, liver tumor, and hepatotoxic drugs damage. Magnetic nanoparticles were covered in a core/shell type with silica, aminosilane, and a double shell of silica-aminosilane. A ScFv (fragment antibody) and anti-CD73 antibody were attached to the coated nanoparticles in order to separate the enzyme. The magnetic separation of t...
Phycotoxins: Chemistry and Biochemistry
Maitotoxin (MTX) is the most potent (LD50 = 0.05 mg/kg, mouse ip injection) and largest (3422 D) ... more Maitotoxin (MTX) is the most potent (LD50 = 0.05 mg/kg, mouse ip injection) and largest (3422 D) nonpeptide marine toxin described (Yasumoto 2000). MTX increases cytosolic free calcium ([Ca2+]i) in all cell types tested by activating Ca2+ entrance. In contrast, MTX does not ...
Proceedings of the National Academy of Sciences, 2004
The yeast Saccharomyces cerevisiae was engineered to express the ρ1 subunit of the human γ-aminob... more The yeast Saccharomyces cerevisiae was engineered to express the ρ1 subunit of the human γ-aminobutyric acid ρ1 (GABAρ1) receptor. RNA that was isolated from several transformed yeast strains produced fully functional GABA receptors in Xenopus oocytes. The GABA currents elicited in the oocytes were fast, nondesensitizing chloride currents; and the order of agonist potency was GABA > β-alanine > glycine. Moreover, the receptors were resistant to bicuculline, strongly antagonized by (1,2,5,6 tetrahydropyridine-4-yl)methylphosphinic acid, and modulated by zinc and lanthanum. Thus, the GABA receptors expressed by the yeast mRNA retained all of the principal characteristics of receptors expressed by cRNA or native retina mRNAs. Western blot assays showed immunoreactivity in yeast plasma membrane preparations, and a ρ1-GFP fusion gene showed mostly intracellular distribution with a faint fluorescence toward the plasma membrane. In situ immunodetection of ρ1 in yeast demonstrated tha...
Plant Physiology and Biochemistry, 2007
Arsenite (As(III)) and arsenate (As(V)) uptake by peas was investigated using inductively coupled... more Arsenite (As(III)) and arsenate (As(V)) uptake by peas was investigated using inductively coupled plasma/optical emission spectroscopy (ICP-OES) at pH below 4 and at pH 5.8. Additionally, total amylolitic activity and alpha-amylase (1,4-alpha-d-glucan glucanohydrolase; EC 3.2.1.1) activity was assayed in plants exposed to arsenic treatments. At pH below 4, the uptake for As(III) and As(V) in roots was 137 and 124 mg As kg(-1) dry weight (d wt), respectively. Translocation of arsenic to the aerial part was relatively low ( approximately 5mg As kg(-1) d wt). The uptake for As(III) and As(V) in roots at pH 5.8 was about 43 and 30 mg As kg(-1) d wt, respectively, and translocation of As to the aerial part was not detectable. None of the arsenic treatments affected the total amylolitic activity in roots; however, the shoots from all treatments showed an increase in the total amylolitic activity. Alpha-amylase activity in the pea leaves was not significantly affected by arsenic treatments. X-ray absorption spectroscopy (XAS) studies showed a reduction of As(V) to As(III) in the roots. From linear combination X-ray absorption near edge structure (LC-XANES) fittings, it was determined that arsenic was present as a mixture of As(III) oxide and sulfide in pea roots.
Neuroscience Letters, 1997
The monoclonal antibody AE-1 raised against acetylcholinesterase (AChE) from human erythrocytes (... more The monoclonal antibody AE-1 raised against acetylcholinesterase (AChE) from human erythrocytes (HE) is shown to react with active asymmetric and tetrameric AChE components from rabbit muscle microsomes (RMM), and with tetrameric forms from human brain (HB) or fetal bovine serum (FBS). However, it failed to bind to AChE monomers from RMM or HB. The results of Western blot revealed that the determinant for AE-1 consisted of a conformational domain, not a primary sequence region, in the AChE subunit. The antibody recognized HE monomers and FBS dimers, but not FBS monomers. The formation of labile immunocomplexes between AE-1 and AChE subunits may explain the lack of interaction between the antibody and the monomers from non-erythrocyte sources.
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Papers by Alejandro Martinez