Modulation of Functional Phosphorylation Sites by Basic Residues in the Unique Domain of c-Src.

In contrast to the well-studied canonical regulatory mechanisms, the way by which the recently discovered Src N-terminal regulatory element (SNRE) modulates Src activity is not yet well understood. Phosphorylation of serine and threonine residues modulates the charge distribution along the disordered region of the SNRE and may affect a fuzzy complex with the SH3 domain that is believed to act as an information transduction element. The pre-existing positively charged sites can interact with the newly introduced phosphate groups by modulating their acidity, introducing local conformational restrictions, or by coupling various phosphosites into a functional unit. In this paper, we use pH-dependent NMR measurements combined with single point mutations to identify the interactions of basic residues with physiologically important phosphorylated residues and to characterize the effect of these interactions in neighbor residues, thus providing insight into the electrostatic network in the isolated disordered regions and in the entire SNRE. From a methodological point of view, the linear relationships observed between the mutation-induced pKa changes of the phosphate groups of phosphoserine and phosphothreonine and the pH-induced chemical shifts of the NH groups of these residues provide a very convenient alternative to identify interacting phosphate groups without the need to introduce point mutations on specific basic residues.

Anesthetic considerations in patients with implantable devices and chronic pain surgery / Consideraciones anestésicas en pacientes con dispositivos implantables y para cirugía de dolor crónico

Abstract The use of advanced invasive techniques for the control of chronic pain in patients with multiple comorbidities is becoming increasingly common. Neuromodulation offers a new management alternative involving the infusion of one or more drugs into the epidural or intrathecal space through a fully implantable infusion pump. It also involves spinal stimulation, a minimally invasive technique in which electrodes are positioned in the epidural space and connected to a pulse generator that is implanted subcutaneously and generates pulses designed to suppress the noxious stimulus. This article will describe the anesthetic considerations in cases of implantable drug delivery systems, and spinal and peripheral nerve stimulation devices. Additionally, patients with electrical or drug neuromodulation devices may present to anesthetic practice for surgical indications unrelated to their chronic pain pathology. Hence the importance of being familiar with the basic components of these devices, how they work, what drugs they use and the potential associated complications in the perioperative context, in order to ensure proper management and patient safety.

Resumen Cada vez es más común el empleo de técnicas invasivas avanzadas para el control del dolor crónico en paciente con múltiples comorbilidades. La neuro-modulación ofrece una nueva alternativa de manejo, que involucra la infusión de uno o más medicamentos en el espacio epidural o intratecal a través de una bomba de infusión totalmente implantable. También incluye la estimulación espinal, una técnica mínimamente invasiva que consiste en el posicionamiento de electrodos en el espacio epidural, conectados a un generador de pulso que se implanta subcutáneo y genera pulsos que buscan suprimir el estímulo nocivo. En este artículo se hará la descripción de las consideraciones anestésicas que se deben tener con sistemas de liberación de medicamentos implantables, dispositivos de estimulación medular y de nervio periférico. Adicionalmente, pueden aparecer pacientes portadores de dispositivos de neuromodulación eléctrica o medicamentosa que deben recibir anestesia para someterse a cirugía por razones diferentes a su patología de dolor crónico y deben conocerse sus implicaciones anestésicas. Por lo anterior, es importante conocer y estar familiarizados con los componentes básicos de dichos dispositivos: funcionamiento, medicamentos que utilizan y las potenciales complicaciones que se puedan tener con estos en el contexto perioperatorio, para garantizar un manejo adecuado y la seguridad del paciente.

Phytochemical Screening and Antioxidant Activity of Seven Native Species Growing in the Forests of Southern Chilean Patagonia.

The genus Nothofagus is one of the most abundant in the subantarctic Patagonian forests. Five species inhabit these ecosystems, three evergreen (Nothofagus betuloides, Nothofagus dombeyi, and Nothofagus nitida) and two deciduous (Nothofagus pumilio and Nothofagus antarctica). This is the first report on the levels of secondary metabolites and the antioxidant capacity of Patagonian tree species growing in natural environments. The aim of this work was to carry out a phytochemical screening, to determine the antioxidant capacity, the sun protection factor, and the α-glucosidase and tyrosinase inhibitory activity of foliar extracts of the five previous species. Besides, Aristotelia chilensis and Berberis microphylla, two species of Patagonian shrubs growing in the same forests, were used as reference. N. dombeyi was the Nothofagus with the best antioxidant capacity. B. microphylla differed from all studied species. Moreover, the Nothofagus was split into two groups. N. betuloides and N. dombeyi are the most similar species to A. chilensis. The α-glucosidase was completely inhibited by all studied extracts. Furthermore, N. antarctica, N.pumilio, and N. nitida inhibited about 70% of the tyrosinase activity. All the results found in this study for the species of the genus Nothofagus support further research on their potential beneficial properties for human health.

Inadequate prediction of postoperative complications in breast cancer surgery: An evaluation of the ACS Surgical Risk Calculator.

BACKGROUND: The American College of Surgeon (ACS) Surgical Risk Calculator is an online tool that helps surgeons estimate the risk of postoperative complications for numerous surgical procedures across several surgical specialties. METHODS: We evaluated the predictive performance of the calculator in 385 cancer patients undergoing breast surgery. Calculator-predicted complication rates were compared with observed complication rates; calculator performance was evaluated using calibration and discrimination analyses. RESULTS: The mean calculator-predicted rates for any complication (4.1%) and serious complication (3.2%) were significantly lower than the observed rates (11.2% and 5.2%, respectively). The area under the curve was 0.617 for any complication and 0.682 for serious complications. p Values for the Hosmer-Lemeshow test were significant (<.05) for both outcomes. Brier scores were 0.102 for any complication and 0.048 for serious complication. CONCLUSIONS: The ACS risk calculator is not an ideal tool for predicting individual risk of complications following breast surgery in a Mexican cohort. The most valuable use of the calculator may reside in its role as an aid for patient-led surgery planning. The possibility of introducing breast surgery-specific data could improve the performance of the calculator. Furthermore, a disease-specific calculator could provide more accurate predictions and include complications more frequently found in breast cancer surgery.

Synthesis, conformational analysis, and cytotoxicity of conformationally constrained aplidine and tamandarin A analogues incorporating a spirolactam beta-turn mimetic.

With the aim of studying the contribution of the beta II turn conformation at the side chain of didemnins to the bioactive conformation responsible for their antitumoral activity, conformationally restricted analogues of aplidine and tamandarin A, where the side chain dipeptide Pro8-N-Me-d-Leu7 is replaced with the spirolactam beta II turn mimetic (5R)-7-[(1R)-1-carbonyl-3-methylbutyl]-6-oxo-1,7-diazaspiro[4.4]nonane, were prepared. Additionally, restricted analogues, where the aplidine (pyruvyl9) or tamandarin A [(S)-Lac9] acyl groups are replaced with the isobutyryl, Boc, and 2-methylacryloyl groups, were also prepared. These structural modifications were detrimental to cytotoxic activity, leading to a decrease of 1-2 orders of magnitude with respect to that exhibited by aplidine and tamandarin A. The conformational analysis of one of these spirolactam aplidine analogues, by NMR and molecular modeling methods, showed that the conformational restriction caused by the spirolactam does not produce significant changes in the overall conformation of aplidine, apart from preferentially stabilizing the trans rotamer at the pyruvyl9-spirolactam amide bond, whereas in aplidine both cis and trans rotamers at the pyruvyl9-Pro8 amide bond are more or less equally stabilized. These results seem to indicate a preference for the cis form at that amide bond in the bioactive conformation of aplidine. The significant influence of this cis/trans isomerism upon the cytotoxicity suggests a possible participation of a peptidylprolyl cis/trans isomerase in the mechanism of action of aplidine.

Analysis of conformational equilibria in aplidine using selective excitation 2D NMR spectroscopy and molecular mechanics/dynamics calculations.

Aplidine (dehydrodidemnin B), a natural product with potent antitumor activity currently in multicenter phase II clinical trials, exists in DMSO as a mixture of four slowly interconverting conformations in a ratio of 47:33:13:7. NMR spectroscopy shows that these arise as a consequence of cis/trans isomerization about the NMe-Leu(7)-Pro(8) and Pro(8)-Pyr amide bonds of the molecule's side chain. Two major conformations account for 47% and 33% of the total population, a ratio of 60:40 between the two. They correspond to the cis- and trans-isomers, respectively, about the Pro(8)-Pyr amide bond. Two minor conformers arise as a consequence of similar isomerism about the Pro(8)-Pyr amide bond, but in structures in which the NMe-Leu(7)-Pro(8) amide bond is cis rather than trans. These account for approximately 13% and 7% of the total population, corresponding to a ratio of 65:35 cis/trans, respectively. Molecular dynamics simulations show that the three-dimensional structures of all four conformational isomers are similar in the macrocycle and that all are essentially unchanged with respect to the macrocycle of didemnin B. Significant differences in the conformation of the molecule's side chain are, however, observed between major and minor pairs. Analysis of hydrogen-bonding patterns shows that each major conformer exhibits a beta-turn like structure and is stabilized by hydrogen bonding between a different carbonyl group of the pyruvyl unit of the molecule's side chain and the NH of the Thr(6) residue. The minor isomers have a cis-amide bond between the NMe-Leu(7) and Pro(8) residues that obliges the side chain to adopt an extended disposition where hydrogen bonding to the macrocycle is absent. These results suggest that the ability of the molecule's side chain to adopt a beta-turn-like conformation may not be a prerequisite for biological activity in the didemnins and that conformations having an extended side-chain may play a role in the biological activity of aplidine.

Consideraciones de la respuesta inmunológica ocular en la cisticercosis: reporte de dos casos / Immunologic responses in ocular cysticercosis: report of 2 cases

Se presentan 2 casos clínicos de cisticercosis ocular en donde se empleó diagnóstico inmunológico con la prueba de ELISA, la cual resultó altamente positiva en el humor acuoso de ambos pacientes, pero en sólo uno positiva en el suero