Piroxicam and meloxicam ameliorate hepatic oxidative stress and protein carbonylation in Kupffer and sinusoidal endothelial cells promoted by ischemia-reperfusion injury.

The present study was aimed to assess the effect of protein carbonylation (PC) in hepatic cells and effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on indicators of tissue damage induced by liver ischemia-reperfusion injury (LIRI). Warm ischemia was performed by partial vascular occlusion during 90 min in Wistar rats. In serum, we determined the catalytic activity of Alanine Aminotransferase, Aspartate Aminotransferase, Lacticate Dehydrogenase, and Ornithine Carbamoyltransferase. In liver samples, we studied cellular alterations by means of histologic studies, lipid peroxidation, PC by immunohistochemistry, apoptosis and reactive oxygen species in bile by electron paramagnetic resonance. Based on PC data, sinusoidal endothelial cells (SEC) and Kupffer cells (KC) were the first to exhibit LIRI-associated oxidative damage and prior to parenchymal cells. Administration of piroxicam or meloxicam during the pre-ischemic period produced a highly significant decrease in all studied injury indicators. No significant differences were revealed between the protective action of the two drugs. The data shown here suggest the potential use of NSAIDs such as piroxicam or meloxicam in minimizing ischemic event-caused damage in liver. We also propose that PC may be employed as an adequate tool to assess tissue damage after oxidative stress.

Actividad antimicrobiana de bacterias marinas aisladas del Golfo de México / Antimicrobial activity of marine bacteria isolated from Gulf of Mexico

Currently there is a need for new antibiotics with an alternative mode of action and new chemical structures. Bacterial pathogens are gradually becoming more resistant to conventional antibiotics, generating an emergence of infectious diseases and they are becoming a great problem in the field of public health. In this study, seven different isolated bacteria were obtained from offshore seawater and sediment of the Gulf of Mexico from Campeche, Mexico. They were substance producers which inhibit growth of human pathogens like Staphylococcus aureus and Pseudomonas aeruginosa and one of them was a polymer producer on peptone and glucose culture. They were characterized phenotipically by means of morphological techniques and physiologically by conventional tests. Four of them were Gram-positive bacteria and the Scanning Electron Microscope analysis revealed their size between 0.6 – 1.5 µm. One of seven marine strains, Gram negative, yellow pigmented, slightly curved rods, was identified as Pseudoalteromonas sp. on the analysis of the gen16S rRNA sequence.

Hoy en día existe la necesidad de encontrar antibióticos con nuevas estructuras químicas y modos de acción alternativos. Se ha observado que bacterias patógenas comunes progresivamente desarrollan resistencia al tratamiento con antibióticos tradicionales, surgiendo y resurgiendo enfermedades infecciosas que generan un gran problema en salud pública. En este estudio, se obtuvieron siete colonias bacterianas pigmentadas de agua de mar y de sedimento marino procedente de las costas de Campeche, México. Las colonias aisladas produjeron sustancias que inhibieron el crecimiento de bacterias patógenas a humanos como Staphylococcus aureus and Pseudomonas aeruginosa. Las bacterias marinas fueron caracterizadas fenotípicamente de acuerdo a su morfología microscópica y por pruebas fisiológicas convencionales. Cuatro de los aislados resultaron ser bacterias Gram positivas y las otras tres fueron Gram negativas. Cuando se observaron por microscopía electrónica de barrido, su tamaño aproximado fue entre 0,6 – 1,5 µm. Uno de los aislados fue una colonia amarilla con bacilos cortos Gram negativos y ligeramente curvos, identificado por la secuencia del gen16S rRNA como Pseudoalteromonas sp.

A review of actin binding proteins: new perspectives.

Actin binding proteins (ABPs) have been considered components of the cytoskeleton, which gives structure and allows mobility of the cell. The complex dynamic properties of the actin cytoskeleton are regulated at multiple levels by a variety of proteins that control actin polymerization, severing of actin filaments and cross-linking of actin filaments into networks, which may be used by molecular motors. Proteins that cross-link F-actin are important for the maintenance of the viscoelastic properties of the cytoplasm and for the integrity of plasma membrane-associated macromolecules. Most of these F-actin cross-linking proteins have an actin-binding domain homologous to calponin. In addition, some of them have been considered scaffolds. Through the years, several research groups have found different proteins that interact with ABPs; however, the effect of these interactions on ABPs remains mostly unknown. In addition to organize the cytoskeletal structure, recent data indicate that ABPs can also migrate to the nucleus. This fact is in agreement and could be relevant to the recently found role that actin might play in nuclear function. Recent data and analysis of published results have also indicated that scaffold proteins like filamin A (FLNa) may be processed by proteolysis and that the degradation products generated by this reaction may play a role as signaling molecules, integrating nuclear and cytosolic pathways. Some of the relevant information in this area is reviewed here.

Filamina plaquetaria: una proteína del citoesqueleto integradora de la función celular / Platelet filamin: a cytoskeletal protein involved in cell signal integration and function

Activation of cellular receptors by diverse stimuli induces dramatic changes in shape and function to respond to the new circumstances of the cell. This modified behavior depends on the reorganization of the peripheral actin meshwork. An outstanding example of these processes can be found in platelets, from which much of the information available on cytoskeletal function has been obtained. Among the many actin-crosslinking proteins like spectrin, fimbrin or alpha actinin, filamin a (FLNa) emerges as the one with the highest potential in initiating the polimerization of actin filaments (F-actin) during the formation of tridimensional actin gels. FLNa also links actin filaments to the cytosolic domain of many membrane glycoproteins in platelets through its C-terminal region. In addition to participating in cell shape changes, FLNa is a scaffoldding protein that recruits numerous proteins involved in a completely different set of functions, including signal transduction, gene transcription regulation, and receptor translocation; however, the physiological role of FLNa in these processes has remained elusive. The purpose of the present communication is to briefly describe the characteristics of the macromolecules able to interact with FLNa and to discuss a possible role of FLNa during the transduction of signals from those molecular elements in platelets.

Calcineurin dephosphorylates the C-terminal region of filamin in an important regulatory site: a possible mechanism for filamin mobilization and cell signaling.

Filamin is a phosphoprotein that organizes actin filaments into networks. We report that a purified C-terminal recombinant region of filamin is a suitable substrate for calcineurin in vitro. Furthermore, 1 microM cyclosporin A (CsA), a specific calcineurin inhibitor, reduced the dephosphorylation of the recombinant fragment in 293FT cells. Mutagenesis analysis showed that a dephosphorylation step occurred in Ser 2152, which was previously shown to provide resistance to calpain cleavage when endogenous PKA is activated. In contrast, phosphorylation of Ser 2152 was recently reported to be necessary for membrane dynamic changes. In this regard, we found that CsA protects filamin in platelets from calpain degradation. Results could be combined with available information in a single model, assuming that some of the peptide fragments released by calcineurin-regulated calpain action could mediate actions in downstream pathways, which may help to resolve the controversies reported on the role of filamin phosphorylation in actin dynamics.

[Platelet filamin: a cytoskeletal protein involved in cell signal integration and function]. / Filamina plaquetaria: una proteína del citoesqueleto integradora de la función celular.

Activation of cellular receptors by diverse stimuli induces dramatic changes in shape and function to respond to the new circumstances of the cell. This modified behavior depends on the reorganization of the peripheral actin meshwork. An outstanding example of these processes can be found in platelets, from which much of the information available on cytoskeletal function has been obtained. Among the many actin-crosslinking proteins like spectrin, fimbrin or alpha actinin, filamin a (FLNa) emerges as the one with the highest potential in initiating the polimerization of actin filaments (F-actin) during the formation of tridimensional actin gels. FLNa also links actin filaments to the cytosolic domain of many membrane glycoproteins in platelets through its C-terminal region. In addition to participating in cell shape changes, FLNa is a scaffoldding protein that recruits numerous proteins involved in a completely different set of functions, including signal transduction, gene transcription regulation, and receptor translocation; however, the physiological role of FLNa in these processes has remained elusive. The purpose of the present communication is to briefly describe the characteristics of the macromolecules able to interact with FLNa and to discuss a possible role of FLNa during the transduction of signals from those molecular elements in platelets.

Trypanosoma cruzi isolates from Mexican and Guatemalan acute and chronic chagasic cardiopathy patients belong to Trypanosoma cruzi I.

Trypanosoma cruzi is classified into two major groups named T. cruzi I and T. cruzi II. In the present work we analyzed 16 stocks isolated from human cases and four isolated from triatomines from diverse geographical origins (Mexico and Guatemala). From human cases four were acute cases, six indeterminates, and six from chronic chagasic cardiophatic patients with diagnosis of dilated cardiomyopathy established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest X-radiography and impaired contracting ventricle and different degree conduction/rhythm aberrations. DNA samples were analyzed based on mini-exon (ME) polymorphism, using a pool of three oligonucleotide for the amplification of specific intergenic region of T. cruzi ME gene. All the Mexican and Guatemalan isolates regardless their host or vector origin generated a 350 bp amplification product. In conclusion T. cruzi I is dominant in Mexico and Guatemala even in acute and chronic chagasic cardiopathy patients. To our knowledge, this is the first study describing predominance of T. cruzi I in human infection for North and Central America.

Trypanosoma cruzi isolates from Mexican and Guatemalan acute and chronic chagasic cardiopathy patients belong to Trypanosoma cruzi I

Trypanosoma cruzi is classified into two major groups named T. cruzi I and T. cruzi II. In the present work we analyzed 16 stocks isolated from human cases and four isolated from triatomines from diverse geographical origins (Mexico and Guatemala). From human cases four were acute cases, six indeterminates, and six from chronic chagasic cardiophatic patients with diagnosis of dilated cardiomyopathy established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest X-radiography and impaired contracting ventricle and different degree conduction/rhythm aberrations. DNA samples were analyzed based on mini-exon (ME) polymorphism, using a pool of three oligonucleotide for the amplification of specific intergenic region of T. cruzi ME gene. All the Mexican and Guatemalan isolates regardless their host or vector origin generated a 350 bp amplification product. In conclusion T. cruzi I is dominant in Mexico and Guatemala even in acute and chronic chagasic cardiopathy patients. To our knowledge, this is the first study describing predominance of T. cruzi I in human infection for North and Central America.

In situ determination of a PKA phosphorylation site in the C-terminal region of filamin.

A C-terminal region of human endothelial actin-binding protein-280 (ABP-280 or ABP, non-muscle filamin) was subcloned and efficiently expressed in a mammalian cells system as indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting analysis. As predicted by the aminoacid sequence, the fragment, a 79 kD peptide (residues 1671-2361, plus 3.9 kD from an N-terminal fusion peptide included in the expression plasmid), contained the two potential cAMP-dependent protein kinase (PKA) phosphorylation sites (serine 2152 and threonine 2336) predicted to be present in this region of the molecule. Incubation of cells in the presence of cAMP-elevating agents enhanced 32P uptake into the fragment. Site-directed mutagenesis analysis indicated that serine 2152 is the unique substrate in the C-terminal region of ABP for endogenously activated PKA. The functional implications of phosphorylation of this residue, which belongs to a serine-proline motif, are discussed in terms of the role of filamin in cytoskeleton reorganization.

[Phosphorylation of tau and Alzheimer's disease]. / Fosforilación de tau y enfermedad de Alzheimer.

Tau is an important component of neuronal cytosqueleton; the protein stabilizas microtubules, maintains cell shape and axonal transport mechanisms. However, for unknown reasons tau experiments important postranslation modifications including enhanced phosphorilation due to unbalanced activity between kinases and phosphatases, affecting its normal biological function. Under these circumstances tau begins to aggregate into neurofibrillary tangles (NFTS) complexes which are pathological hallmarks of Alzheimer's disease together with senile plaques. This review is mainly concerned with the role that different kinase play into the regulation of tau structure and function.

Fosforilación de tau y enfermedad de Alzheimer / Phosphorylation of Tau and Alzheimer's Disease

Tau forma parte importante del citoesqueleto en neuronas; estabilizando microtúbulos, manteniendo la forma celular y como via de transporte axonal. Sin embargo, por mecanismos desconocidos, tau sufre modificaciones importantes como son fosforilación anormal debida a la actividad desequilibrada de varias cinasas y fosfatasas, afectando su función biológica normal. Bajo estas circunstancias tau comienza a agregarse originando complejos proteicos denominados desarreglos neurofibrilares (NFTS) que son hallazgos histopatológicos característicos de la enfermedad de Alzheimer junto con las placas seniles. Esta revisión esta enfocada principalmente a describir la estructura de tau y la participación de diferentes cinasas en su regulación.

Tau is an important component of neuronal cytosqueleton; the protein stabilizas microtubules, maintains cell shape and axonal transport mechanisms. Howevwe, for unknown reasons tau experiments important postranslation modifications including enhanced phosphorylation due to unbalanced activity between kinases and phosphatases, affecting its normal biological function. Under these circumstances tau begins to aggregate into neurofibrillary tangles (NFTS) complexes which are pathological hallmarks of Alzheimer's disease together with senile plaques. This review is mainly concerned with the role that different kinase play into the regulation of tau structure and function.

[Gene therapy in cardiology]. / Terapia del gen en cardiología.

The modification of genetic material of living cells for therapeutic purposes have been regarded by many as an unrealized promise. However, recent successful achievements in the field have contributed to vanish this perception and have reopened the possibility to use gene therapy as a medical intervention in humans. In the case of cardiovascular diseases, and despite its high prevalence, the number of approved human gene therapy protocols has remained low. This may be due, at least in part, to the availability of effective alternative therapies for some of the most common vasculopathies. However, recent advances in the understanding of the genetic and molecular bases of the cardiovascular system have opened the possibility to introduce gene therapy in the management of a great variety of cardiovascular disorders. The purpose of this communication is to briefly summarize the progress in this area.

Superoxide dismutase activity of the Salicylate-Iron complex

Background. Scavenging of superoxide radical by salicylate-iron complex was studied to determine whether or not the salicylate-iron complex was able to catalyze the dismutation of superoxide radicals, the result perhaps yielding an explanation of the antioxidant and anti-inflammatory properties of the drug. Methods. the scavenging was studied with an assay that generates Oú- 2 without the intervention of metal ions. Results. Results indicated that, in the presence of iron, salicylate was able to bring about the catalytic dismutation of the superoxide radiacal. The rate of superoxide removal was dependent on both the concentration of iron and the salicylate:iron molar ratio. Conclusions. these results may help to explain the interaction of nonsteroidal anti-inflammatory drugs with free radicals and the anti-inflammatory properties of these agents, inasmuch as accumulating evidence indicates that much of the injury observed during inflammatory disorders may be mediated by oxidative stress frequently induced by iron-dependent reactions

Captopril and Glutathione inhibit the superoxide dismutase activity of Hg(II)

El propósito de este estudio fue determinar si el captopril, un inhibidor de la enzima convertidora de angiotensina, y el glutatión podían reaccionar con iones mercúricos y así modificar la dismutación catalítica del superóxido llevada a cabo por este metal. Con un ensayo que genera radicales superóxido, sin la intervención de iones matálicos, concentraciones crecientes de ambos reactivos inhibieron de manera progresiva la dismutación del superóxico llevada a cabo por el mercurio. La inhibición máxima se observó con una relación molar de captopril (glutation): Hg (II) =1. Estos resultados pueden ayudar a explicar el efecto protector y/o antioxidante de los compuestos con tioles durante la intoxicación con mercurio

Bases moleculares de la hipertension arterial inducida por cadmio / Molecular basis of the cadmium induced by arterial hypertension

Con el fin de esclarecer los mecanismos bioquímicos involucrados en el establecimiento de la enfermedad hipertensiva inducida por el cadmio, en este trabajo se estudió el efecto del metal sobre diversas funciones mitocondriales, a saber: transporte de calcio y producción de energía. La presencia de cadmio en el medio inhibe ambas funciones debido a la unión de este metal a los grupos sulfhidrilo presentes en las proteínas de las cuales dependen estos procesos. En base a estos resultados es posible proponer un esquema en el cual el cadmio produce de manera directa un efecto de vasoconstricción renal el cual a su vez explica otros mecanismos que aparecen durante la enfermedad hipertensiva