Artículos en prensa
URI permanente para esta colección
Examinar
Envíos recientes
Ítem Acceso Abierto Draft genome sequence of Janthinobacterium lividum strain MTR reveals its mechanism of capnophilic behavior(BioMed Central Ltd., 2015) Valdes, N.; Soto, P.; Cottet, L.; Alarcon, P.; Gonzalez, A.; Castillo, A.; Corsini, G.; Tello, M.Janthinobacterium lividum is a Gram-negative bacterium able to produce violacein, a pigment with antimicrobial and antitumor properties. Janthinobacterium lividum colonizes the skin of some amphibians and confers protection against fungal pathogens. The mechanisms underlying this association are not well understood. In order to identify the advantages for the bacterium to colonize amphibian skin we sequenced Janthinobacterium lividum strain MTR, a strain isolated from Cajón del Maipo, Chile. The strain has capnophilic behavior, with growth favored by high concentrations (5 %) of carbon dioxide. Its genome is 6,535,606 bp in size, with 5,362 coding sequences and a G + C content of 62.37 %. The presence of genes encoding for products that participate in the carbon fixation pathways (dark CAM pathways), and the entire set of genes encoding for the enzymes of the glyoxylate cycle may explain the capnophilic behavior and allow us to propose that the CO2 secreted by the skin of amphibians is the signal molecule that guides colonization by Janthinobacterium lividum. © 2015 Valdes et al.Ítem Acceso Abierto Cone beam computed tomography (CBCT) as a tool for the analysis of nonhuman skeletal remains in a medico-legal setting(Elsevier Ireland Ltd., 2016) Lucena, J.; Mora, E.; Rodriguez, L.; Muñoz, M.; Cantin, M.G.; Fonseca, G.M.To confirm the nature and forensic significance of questioned skeletal material submitted a medico-legal setting is a relatively common procedure, although not without difficulties when the remains are fragmented or burned. Different methodologies have been described for this purpose, many of them invasive, time and money consuming or dependent on the availability of the analytical instrument. We present a case in which skeletal material with unusual conditions of preservation and curious discovery was sent to a medico-legal setting to determine its human/nonhuman origin. A combined strategy of imagenological procedures (macroscopic, radiographic and cone beam computed tomography - CBCT-technology) was performed as non-invasive and rapid methods to assess the nonhuman nature of the material, specifically of pig (Sus scrofa) origin. This hypothesis was later confirmed by DNA analysis. CBCT data sets provide accurate three-dimensional reconstructions, which demonstrate its reliable use as a forensic tool. © 2016 Elsevier Ireland Ltd.Ítem Acceso Abierto Using autonomous search for solving constraint satisfaction problems via new modern approaches(Elsevier, 2016) Soto, R.; Crawford, B.; Olivares, R.; Galleguillos, C.; Castro, C.; Johnson, F.; Paredes, F.; Norero, E.Constraint Programming is a powerful paradigm which allows the resolution of many complex problems, such as scheduling, planning, and configuration. These problems are defined by a set of variables and a set of constraints. Each variable has non-empty domain of possible value and each constraint involves some subset of the variables and specifies the allowable combinations of values for that subset. The resolution of these problems is carried out by a constraint satisfaction solver which explores a search tree of potential solutions. This exploration is controlled by the enumeration strategy, which is responsible for choosing the order in which variables and values are selected to generate the potential solution. There exist different ways to perform this selection, and depending on the quality of this decision, the efficiency of the solving process may dramatically vary. Autonomous search is a particular case of adaptive systems that aims at improving its solving performance by adapting itself to the problem at hand without manual configuration of an expert user. The goal is to improve their solving performance by modifying and adjusting themselves, either by self-adaptation or by supervised adaptation. This approach has been effectively applied to different optimization and satisfaction techniques such as constraint programming, metaheuristics, and SAT. In this paper, we present a new Autonomous Search approach for constraint programming based on four modern bio-inspired metaheuristics. The goal of those metaheuristics is to optimize the self-tuning phase of the constraint programming search process. We illustrate promising results, where the proposed approach is able to efficiently solve several well-known constraint satisfaction problems. © 2016 Elsevier B.V.Ítem Acceso Abierto Metabolic and inflammatory adaptation of reactive astrocytes: role of PPARs(Humana Press Inc., 2016) Iglesias, J.; Morales, L.; Barreto, G.E.Astrocyte-mediated inflammation is associated with degenerative pathologies such as Alzheimer’s and Parkinson’s diseases and multiple sclerosis. The acute inflammation and morphological and metabolic changes that astrocytes develop after the insult are known as reactive astroglia or astrogliosis that is an important response to protect and repair the lesion. Astrocytes optimize their metabolism to produce lactate, glutamate, and ketone bodies in order to provide energy to the neurons that are deprived of nutrients upon insult. Firstly, we review the basis of inflammation and morphological changes of the different cell population implicated in reactive gliosis. Next, we discuss the more active metabolic pathways in healthy astrocytes and explain the metabolic response of astrocytes to the insult in different pathologies and which metabolic alterations generate complications in these diseases. We emphasize the role of peroxisome proliferator-activated receptors isotypes in the inflammatory and metabolic adaptation of astrogliosis developed in ischemia or neurodegenerative diseases. Based on results reported in astrocytes and other cells, we resume and hypothesize the effect of peroxisome proliferator-activated receptor (PPAR) activation with ligands on different metabolic pathways in order to supply energy to the neurons. The activation of selective PPAR isotype activity may serve as an input to better understand the role played by these receptors on the metabolic and inflammatory compensation of astrogliosis and might represent an opportunity to develop new therapeutic strategies against traumatic brain injuries and neurodegenerative diseases. © 2016 Springer Science+Business Media New YorkÍtem Acceso Abierto Determination of the temperature causing a nociceptive response in the tail of albino BALB/c mice(Spanish Society of Neurology, 2018) Aguirre Siancas, E.E.; Lam Figueroa, N.M.; Delgado Rios, J.C.; Crispín Huamaní, L.J.; Alarcón Velásquez, L.Introduction: Designs for determining nociceptive response in rodents are of great use in neurology and experimental neuroscience. Immersing mice's tails in warm water is one of the most widely used procedures to evaluate this response; however, a wide range of temperatures are used in different studies. Knowing the temperature that produces a powerful nociceptive response in the tail of BALB/c mice is extremely useful. Methods: Eight 2-month-old male BALB/c mice were used. A 14-cm high beaker was filled with water up to 13 cm. The animals’ tails were immersed in the container with a starting temperature of 36 °C. The water temperature was raised in 1 °C increments until we identified the temperatures that produced nociceptive responses. That response was determined by counting the time taken before the mouse shook its tail to remove it from the water. Results: Six of the 8 mice began shaking their tails at the temperature of 51 °C. All animals removed their tails from the water at the temperatures of 54 °C, 55 °C, and 56 °C, taking a mean time of 8.54, 7.99, and 5.33 seconds, respectively. ANOVA applied to the response times for each of the 3 temperatures indicated revealed a value of F=2.8 (P=.123). Conclusions: The response time was statistically similar for the temperatures of 54 °C, 55 °C, and 56 °C; however, the data were less dispersed for the latter temperature. © 2018 Sociedad Española de NeurologíaÍtem Acceso Abierto Cyclic fatigue resistance of heat-treated nickel-titanium instruments after immersion in sodium hypochlorite and/or sterilization(Elsevier Inc., 2018) Pedullà, E.; Benites, A.; La Rosa, G.M.; Plotino, G.; Grande N.M.; Rapisarda, E.; Generali, L.Introduction: The purpose of this study was to assess the effects of sodium hypochlorite (NaOCl) immersion and sterilization on the cyclic fatigue resistance of heat-treated nickel-titanium (NiTi) rotary instruments. Methods: Two hundred ten new 25/.06 Twisted Files (TFs; SybronEndo, Orange, CA) and Hyflex CM (Coltene Whaledent, Cuyahoga Falls, OH) files were divided into 7 groups (n = 15) for each brand. Group 1 (control group) included new instruments that were not immersed in NaOCl or subjected to autoclave sterilization. Groups 2 and 3 were composed of instruments dynamically immersed for 3 minutes in 5% NaOCl solution 1 and 3 times, respectively. Groups 4 and 5 consisted of instruments only autoclaved 1 and 3 times, respectively. Groups 6 and 7 recruited instruments that received a cycle of both immersion in NaOCl and sterilization 1 and 3 times, respectively. Instruments were subsequently subjected to a fatigue test. The surface morphology of fractured instruments was studied by field-emission scanning electron microscopy and x-ray energy-dispersive spectrometric (EDS) analyses. The means and standard deviations of the number of cycles to failure (NCF) were calculated and statistically analyzed using 2-way analysis of variance (P < .05). Results: Comparison among groups indicated no significant difference of NCF (P > .05) except for the groups of TFs sterilized 3 times without and with immersion in NaOCl (P < .05). HyFlex CM files exhibited higher cyclic fatigue resistance than TFs when files were sterilized 3 times, independently from immersion in NaOCl (P < .05). EDS analysis showed the presence of an oxide-rich layer on the Hyflex CM files' external surface. No morphologic or chemical differences were found between files of the same brand subjected to different treatments. Conclusions: Repeated cycles of sterilization did not influence the cyclic fatigue of NiTi files except for TFs, which showed a significant decrease of flexural resistance after 3 cycles of sterilization. Immersion in NaOCl did not reduce significantly the cyclic fatigue resistance of all heat-treated NiTi files tested. © 2018 American Association of Endodontists.Ítem Acceso Abierto Cryopreservation of Peruvian Paso horse spermatozoa: Dimethylacetamide preserved an optimal sperm function compared to dimethyl sulfoxide, ethylene glycol and glycerol(Blackwell Publishing Ltd, 2016) Santiani, A.; Evangelista-Vargas, S.; Vargas, S.; Gallo, S.; Ruiz, L.; Orozco, V.; Rosemberg, M.The objective was to evaluate the effect of different cryoprotectant agents in the cryopreservation of Peruvian Paso horse semen. Twenty semen samples were collected from five Peruvian Paso horse stallions. Each sample was divided into 12 parts to form the groups: dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol (GLY), at 3%, 4% and 5%. Samples were frozen using a rate-controlled freezer. Sperm parameters evaluated were motility and viability/acrosomal status. After thawing, progressive motility in DMA group was higher (p < .05) than in DMSO, EG and GLY groups. Similarly, viable acrosome-intact spermatozoa were higher (p < .05) using DMA in comparison with DMSO. No differences were found when comparing concentrations for any of the cryoprotectant agents. In conclusion, DMA seems to be a good cryoprotectant agent for the cryopreservation of Peruvian Paso horse stallion semen. © 2016 Blackwell Verlag GmbH.Ítem Acceso Abierto Ischemic stroke and six genetic variants in CRP, EPHX2, FGA, and NOTCH3 genes: a meta-analysis(W.B. Saunders, 2016) González-Giraldo Y.; Barreto, G.E.; Fava, C.; Forero, D.A.Background: Ischemic stroke (IS) is a leading cause of death and disability worldwide. As genetic heritability for IS is estimated at about 35%-40%, the identification of genetic variants associated with IS risk is of great importance. The main objective of this study was to carry out a meta-analysis for polymorphisms in CRP, EPHX2, FGA, and NOTCH3 genes and the risk for IS. Methods: Literature search for 6 candidate polymorphisms and IS was conducted using HuGE Navigator, PubMed, and Google Scholar databases. Meta-Analyst program was used to calculate pooled odds ratios (ORs) with a random effects model. Results: Twenty-five published studies for 6 candidate polymorphisms were included: CRP-rs1800947 (5 studies), CRP-rs1205 (3 studies), EPHX2-rs751141 (5 studies), FGA-rs6050 (6 studies), NOTCH3-rs3815188 (3 studies), and NOTCH3-rs1043994 (3 studies), for a total number of 7,825 IS cases and 56,532 control subjects. We did not find significant pooled ORs (P values > .05) for any of the genetic variants evaluated in this work. Conclusions: Our meta-analysis results did not show significant associations between these 6 polymorphisms in 4 candidate genes and IS, despite the functional role of some of these single nucleotide polymorphisms (e.g., rs6050 in FGA gene). Future studies are needed to identify additional main genetic risk factors for IS in different populations. © 2016 National Stroke Association.Ítem Acceso Abierto Traducción, adaptación cultural y validación del Salt Knowledge Questionnaire al idioma español [Translation, cultural adaptation and validation of the Salt Knowledge Questionnaire to the Spanish language](Ediciones Doyma, S.L., 2017) Quinteros-Reyes, C.; Marcionelli-Sandhaus, T.; Mayta-Tristán, P.Introduction: In order to reduce salt consumption in Spanish speaking countries it is necessary to know the level of salt knowledge in the population. However, there are no tools in Spanish to measure salt knowledge, but the only valid tool of measurement is the 'Salt Knowledge Questionnaire' (SKQ) developed in Australia, in English. Materials and methods: A validation study was conducted in three phases: (Phase. 1) Translation of the original Australian version into Spanish; (Phase. 2) Cultural adaptation based on a Spanish-speaking population such as Peru and following criteria used in the development of the original questionnaire which was evaluated by a panel of experts; (Phase. 3) Construct validity by comparing the scores of three groups (experts, medical students and non-experts) and reliability by performing a test retest. Results: The translation of the SKQ into Spanish maintained a semantic equivalence with the original questionnaire and a panel of experts accepted the cultural adaptation. The SKQ enables discrimination between those who know and those who do not because differences of scores were found between the group of experts, students and non-experts (P <. .001). A good overall internal consistency of the instrument was found (KR20 = 0.69) and a good overall intraclass correlation (0.79) and no test variations in test-retest (P >. .05). Conclusions: The SKQ questionnaire in Spanish is valid, reliable and is a suitable first tool to measure knowledge about salt in the Spanish language. It is considered possible to adapt it culturally to the Spanish-speaking country that wishes to use it. © 2017 SEH-LELHA.Ítem Acceso Abierto First Latin American clinical practice guidelines for the treatment of systemic lupus erythematosus: Latin American Group for the Study of Lupus (GLADEL, Grupo Latino Americano de Estudio del Lupus)-Pan-American League of Associations of Rheumatology (PANLAR)(BMJ Publishing Group, 2018) Pons-Estel, B.A.; Bonfa, E.; Soriano, E.R.; Betancur, G.V.; Alarcón, G.S.Systemic lupus erythematosus (SLE), a complex and heterogeneous autoimmune disease, represents a significant challenge for both diagnosis and treatment. Patients with SLE in Latin America face special problems that should be considered when therapeutic guidelines are developed. The objective of the study is to develop clinical practice guidelines for Latin American patients with lupus. Two independent teams (rheumatologists with experience in lupus management and methodologists) had an initial meeting in Panama City, Panama, in April 2016. They selected a list of questions for the clinical problems most commonly seen in Latin American patients with SLE. These were addressed with the best available evidence and summarised in a standardised format following the Grading of Recommendations Assessment, Development and Evaluation approach. All preliminary findings were discussed in a second face-to-face meeting in Washington, DC, in November 2016. As a result, nine organ/system sections are presented with the main findings; an 'overarching' treatment approach was added. Special emphasis was made on regional implementation issues. Best pharmacologic options were examined for musculoskeletal, mucocutaneous, kidney, cardiac, pulmonary, neuropsychiatric, haematological manifestations and the antiphospholipid syndrome. The roles of main therapeutic options (ie, glucocorticoids, antimalarials, immunosuppressant agents, therapeutic plasma exchange, belimumab, rituximab, abatacept, low-dose aspirin and anticoagulants) were summarised in each section. In all cases, benefits and harms, certainty of the evidence, values and preferences, feasibility, acceptability and equity issues were considered to produce a recommendation with special focus on ethnic and socioeconomic aspects. Guidelines for Latin American patients with lupus have been developed and could be used in similar settings. © Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.Ítem Acceso Abierto Detection of intracellular reactive oxygen species (superoxide anion and hydrogen peroxide) and lipid peroxidation during cryopreservation of alpaca spermatozoa(Blackwell Publishing Ltd, 2017) Evangelista-Vargas, S.; Santiani, A.Contents: The objective of this study was to detect changes in intracellular reactive oxygen species (superoxide anion and hydrogen peroxide) production and lipid peroxidation during cryopreservation of alpaca spermatozoa. Twelve alpaca semen samples were conventionally cryopreserved. Intracellular superoxide anion and hydrogen peroxide were evaluated by fluorescence microscopy using dihydroethidium (DHE)/YO-PRO-1 and dichlorofluorescein diacetate (H2DCFDA)/propidium iodide (PI), respectively. Evaluations were performed during cooling curve at (1) 25°C, (2) 15°C, (3) 5°C/0 min, (4) 5°C/15 min, (5) 5°C/30 min and (6) after freezing/thawing. Evaluation of lipid peroxidation by measuring malondialdehyde (MDA) was performed at 25°C, 5°C/30 min and after thawing. Maximum percentages of total spermatozoa producing superoxide anion and hydrogen peroxide were found at 5°C/30 min (62.8 ± 6.3% and 30.5 ± 5.6%, respectively), and these results were higher (p < .05) than initial (25°C: 10.8 ± 3.8% and 6.8 ± 0.7%, respectively) and after thawing (29.8 ± 9.5% and 7.5 ± 1.8%, respectively) values. However, considering only viable spermatozoa, production of superoxide anion and hydrogen peroxide during overall stabilization at 5°C (>76% and >91%, respectively) and after thawing (74.9 ± 5.0% and 78.9 ± 2.2%, respectively) was higher (p < .05) than initial values at 25°C (38.7 ± 3.1% and 53.6 ± 2.0%, respectively). Lipid peroxidation at 25°C, 5°C/30 min, and post-thawing were 346.5 ± 99.8, 401.1 ± 64.8 and 527.7 ± 142.8 ng/ml MDA, respectively. These results showed that high percentage of viable alpaca spermatozoa produces intracellular reactive species oxygen (ROS) during the cryopreservation process of alpaca semen. © 2017 Blackwell Verlag GmbH.Ítem Acceso Abierto Factors predictive of high disease activity early in the course of SLE in patients from a Latin-American cohort(W.B. Saunders, 2017) Pimentel-Quiroz, V.R.; Ugarte-Gil, M.F.; Pons-Estel, G.J.; Soriano, E.R.; Saurit V.; Sato, E.I.; Lavras Costallat, L.T.; Molina J.F.; Iglesias-Gamarra, A.; Reyes-Llerena, G.; Neira O.J.; Barile L.A.; Silveira, L.H.; Segami, M.I.; Chacón-Díaz, R.; Wojdyla, D.; Alarcón, G.S.; Pons-Estel, B.A.Aims: To determine the factors predictive of disease activity early in the course of SLE (baseline visit). Methods: Patients from GLADEL, a multi-national, multi-ethnic, Latin-American lupus cohort were included. Disease activity was evaluated at baseline with the SLEDAI score. Demographic characteristics (age at diagnosis, gender, ethnicity, marital status, educational level, medical coverage and socioeconomic status) were assessed. Disease duration was defined as the time between the fourth ACR criterion and baseline. Time to criteria accrual was defined as the interval between the first and fourth ACR criterion. Use of glucocorticoids was recorded as the highest dose received before the baseline visit. Antimalarials and immunosuppressive drugs were recorded as use or not use. Univariable and multivariable analysis were performed. Model selection was based on backward elimination. Results: One thousand two hundred sixty-eight patients were included; 1136 (89.6%) of them were female. Mean age at diagnosis was 29.2 (SD: 12.3) years. Five hundred sixty-five (44.6%) were Mestizo, 539 (42.5%) were Caucasians and 164 (12.9%) were African-Latin-Americans. The mean SLEDAI at baseline was 10.9 (SD: 8.4). Longer time between first and fourth ACR criterion, medical coverage, a dose of prednisone between 15 and 60. mg/d, and the use of antimalarials were factors protective of disease activity, while Mestizo and African-Latin-American ethnicities were predictive factors. Conclusions: Mestizo and African-Latin-American ethnicities were predictive whereas antimalarial use, medical coverage, and longer time to criteria accrual were protective of higher disease activity early in the disease course. © 2017 Elsevier Inc.Ítem Acceso Abierto Effect of a salt-reduction strategy on blood pressure and acceptability among customers of a food concessionaire in Lima, Peru(Blackwell Publishing Ltd, 2018) Reynoso-Marreros, I.A.; Piñarreta-Cornejo, P.K.; Mayta-Tristán, P.; Bernabé-Ortiz, A.Aim: Limited information exists regarding the implementation of salt reduction strategies on collective food services, such as restaurants and food concessionaires. The present study aimed to assess the effect of a salt reduction strategy on blood pressure levels and food acceptability among customers of a food concessionaire. Methods: A quasi-experimental study with two phases was conducted. In the pre-intervention phase, the amount of salt used in food preparation was determined. In the intervention phase, a reduction of 20% in salt added to food preparations was implemented. Four hedonic tests and two blood pressure measurements were performed before and after the intervention implementation using standardised techniques. In addition, an evaluation of uneaten food was conducted daily on all customers' plates. Mixed linear regression models were generated to assess the effect of the intervention on blood pressure and acceptability. Results: A total of 71 workers were evaluated, mean age of 37.5 years, 57.8% females, who consumed the food of the concessionaire, on average, 4.4 (SD: 0.7) days per week. Systolic and diastolic blood pressure were reduced by 3.1 (P<0.001) and 2.9 (P<0.001) mmHg at the end of the study, respectively. The results of the hedonic tests and the uneaten food before and after the intervention did not vary significantly. Conclusions: The reduction of 20% of salt added to food from a concessionaire had a positive impact on the reduction of customers' blood pressure without reducing food acceptability. This strategy could be implemented in other contexts. © 2018 Dietitians Association of Australia.Ítem Acceso Abierto Laparoscopic surgery in nonparasitic cysts of the liver: results observed in a series of consecutive cases(Lippincott Williams and Wilkins, 2016) Manterola, C.; Otzen, T.The purpose of this study was to report the results of laparoscopic treatment of nonparasitic cysts of the liver (NPCL) in terms of postoperative morbidity (POM) and recurrence. Prospective case series of patients operated on for NPCL at the Clínica Mayor in Temuco, Chile (2008 to 2015). The preoperative study consisted of general examinations, abdominal ultrasound or computed tomographic scan. The outcome variable was POM. Other variables of interest were surgical time, need for conversion, hospital stay, mortality, and recurrence. In the study period, 41 patients with NPCL underwent surgery. Median age of the series was 58 years, and 75.6% of the cases were female. The median ultrasound diameter of the lesions was 10 cm and surgical time was 50 minutes. All patients underwent a cystectomy. There was no conversion, no record of POM, mortality or recurrence. The treatment applied in this series of NPCL is associated with an adequate postoperative evolution. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.