Fisiopatología de la sepsis por gram positivos

Las bacterias gram positivas vienen cobrando importancia como agentes etiológicos de la sepsis siendo algunos de principales representantes Staphylococcus aureus, las cepas de S.aureus meticilino resistentes (MRSA del inglés) y el Streptococcus pyogenes o también llamado Streptococcus del grupo A invasivo (GAS). Dado que en su estructura celular presentan diversas moléculas que pueden ser reconocidas como patrones moleculares asociados a patógenos (PAMPs) como son el peptidoglicano (PNG) el ácido teicoico (LTA), las lipoproteínas; y otras que activan directamente el sistema inmune adaptativo como son los Superantígenos; los pacientes infectados pueden exponerse de manera simultánea a una respuesta inmune amplifi cada de manera sinérgica entre todos estos tipos de antígenos, que a través de vías de señalización intracelular desencadenarán la transcripción de genes codifi cadores de citocinas pro infl amatorias como el TNFα, la IL-1β, la IL-6, el INFγ, IL-8, IL-18, IL-2, IL-12, IL-10 que darán lugar a muchas de las manifestaciones clínicas de la sepsis y se vienen asociando como predictores del pronóstico de esta junto a otros marcadores moleculares de la misma

Fisiopatología de la sepsis por bacterias gram negativas: bases moleculares

La sepsis constituye un complejo síndrome en el que a consecuencia de una respuesta anómala del huésped frente a una infección se desencadenan una serie de mecanismos fi siopatológicos celulares y moleculares que se traducirán en el daño multiorgánico del paciente y su respectivas manifestaciones clínicas. Las bacterias gram negativas, gracias al lipopolisacárido (LPS), principal constituyente de su membrana externa son reconocidas por moléculas como la proteína de unión al lipopolisacàrido (LBP) y por complejos de receptores de membrana celular en el huésped que reconocen su estructura antigénica como son el TLR4, el CD14 y la MD2, dando lugar, por medio de diferentes vías de señalización mieloide dependiente (MyD88) y mieloide independiente o TRIF, a la activación de una serie de kinasas que fi nalmente a través de vías de señalización intracelular como NF – kB, generarán cambios transcripcionales que inducirán la producción de citocinas pro infl amatorias, que explican el Síndrome de respuesta inflamatoria sistémica (SIRS) y las antinfl amatorias, que explican el síndrome de repuesta anti infl amatorio compensatorio (CARS), ambos constituyen las fases de la sepsis a través de los cuales pasa el paciente séptico en diferentes momentos del proceso. Todos estos procesos fisiopatológicos moleculares de la sepsis son los que darán como resultado cambios en el endotelio, la microvasculatura, el sistema del complemento, la coagulación y finalmente en cada uno de los órganos del paciente las diferentes manifestaciones clínicas que desde scores de valoración del paciente, como el SOFA, permiten identificar al paciente en sepsis, su pronóstico y directrices acerca del tratamiento. Es así como la comprensión de las bases fisiopatológicas moleculares de las sepsis por gram negativos constituyen hoy en día la base para su definición, la comprensión de la clínica y el punto de partida para mejoras terapéuticas en el manejo de la sepsis, traducida en la supervivencia del paciente

Efeitos da rega superficial e subsuperficial sobre a fisiologia e produção da variedade ‘Godello’ na Galiza, Noroeste de Espanha

Irrigation has been considered a controversial practice in European traditional viticulture due to potential alterations in the balance between vegetative growth and yield. In this regard, the influence of surface (DI) and subsurface (SDI) drip irrigation on physiological performance of the ‘Godello’ grapevine (Vitis vinifera L.) cultivar was compared with a non-irrigated control (R) over three consecutive growing seasons (2012- 2014) in NW Spain. Irrigation improved vine water status; R plants reached a minimum of midday leaf water potential of –1.5 MPa, whereas DI and SDI plants reached –1.3 MPa. Stomatal conductance was unaffected by irrigation as well as chlorophyll a fluorescence. However, photosynthetic pigments were present at higher concentrations in leaves from irrigated plants than in those from R plants in 2013. In addition, R plants showed higher values for the indicators of oxidative damage. No significant yield improvements were observed for irrigated plants, although the trend was to obtain slightly higher yields under irrigation in years with low rainfall amounts. This may not encourage growers to establish irrigation systems on their vineyards. However, these results may be important with the objectives of stabilizing yield from year to yearA rega tem sido considerada uma prática controversa na viticultura tradicional Europeia devido a potenciais alterações no equilíbrio entre crescimento vegetativo e rendimento. A este respeito, a influência da irrigação por gotejamento superficial (DI) e subsuperficial (SDI) sobre o desempenho fisiológico da variedade ‘Godello’ (Vitis vinifera L.) foi comparada com uma testemunha em condições de sequeiro (R) ao longo de três anos consecutivos (2012-2014) no noroeste de Espanha. A rega melhorou o estado hídrico da videira; as plantas do tratamento R atingiram potenciais hídricos foliares ao meio-dia de –1.5 MPa, comparativamente a um valor de –1.3 MPa para as plantas dos tratamentos DI e SDI. A conductância estomática e a fluorescência da clorofila a não foram afectadas pela rega. No entanto, os pigmentos fotossintéticos apresentaram maiores concentrações em folhas de plantas regadas quando se comparam com as plantas do tratamento R em 2013. Além disso, as plantas do tratamento R apresentaram valores superiores para os indicadores de danos oxidativos. Não foi detectado nenhum incremento do rendimento nas plantas regadas, embora se tenha observado uma tendência para obtenção de rendimentos ligeiramente mais elevados sob rega em anos com baixa pluviosidade. Tal poderá não encorajar aos viticultores a implementar sistemas de rega nas suas vinhas. No entanto, estes resultados podem ser importantes para a estabilização do rendimento de ano para anoThis research was supported by the Spanish Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Project nº RTA2011-00041-C02-00, with 80% FEDER funds. J.M. Mirás-Avalos and E.M. Martínez thank Xunta de Galicia for funding their contracts through the “Isidro Parga Pondal” and “Isabel Barreto” Programmes. E. Trigo-Córdoba thanks INIA for their PhD scholarship (FPI-INIA)S

Clinical and Genetic Spectrum of Stargardt Disease in Argentinean Patients

Purpose: To describe the clinical and molecular spectrum of Stargardt disease (STGD) in a cohort of Argentinean patients. Methods: This retrospective study included 132 subjects comprising 95 probands clinically diagnosed with STGD and relatives from 16 of them. Targeted next-generation sequencing of the coding and splicing regions of ABCA4 and other phenocopying genes (ELOVL4, PROM1, and CNGB3) was performed in 97 STGD patients. Results: We found two or more disease-causing variants in the ABCA4 gene in 69/95 (73%) probands, a single ABCA4 variant in 9/95 (9.5%) probands, and no ABCA4 variants in 17/95 (18%) probands. The final analysis identified 173 variants in ABCA4. Seventy-nine ABCA4 variants were unique, of which nine were novel. No significant findings were seen in the other evaluated genes. Conclusion: This study describes the phenotypic and genetic features of STGD1 in an Argentinean cohort. The mutations p.(Gly1961Glu) and p.(Arg1129Leu) were the most frequent, representing almost 20% of the mutated alleles. We also expanded the ABCA4 mutational spectrum with nine novel disease-causing variants, of which eight might be associated with South American natives.Fil: Mena, Marcela Daniela C. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Moresco, Angélica A.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Vidal, Sofía H.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Aguilar Cortes, Diana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Obregon, María G.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Fandiño, Adriana Cristina. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Sendoya, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Llera, Andrea Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Podhajcer, Osvaldo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentin

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC

Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1%of the total study area).Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forestmanagement, natural regeneration of second-growth forests provides a low-costmechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. © 2016 The Authors

Biodiversity recovery of Neotropical secondary forests

Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved

Vegetation structure, composition, and species richness across a 56-year chronosequence of dry tropical forest on Providencia Island, Colombia

We compared vegetation structure and species richness across a 56-yr chronosequence of six replicated age classes of dry tropical forest on the island of Providencia, Colombia, in the Southwest Caribbean. Stand age classes were determined using sequential, orthorectified panchromatic aerial photos acquired between 1944 and 1996 and Landsat 7 ETM + satellite imagery from 2000. Along the chronosequence we established 59 plots of 2 x 50 m (0.01 ha) to document changes in species richness, basal area, tree height, stem density, and sprouting ability. All woody trees and shrubs \u3e2.5 cm diameter at breast height (DBH) were censused and measured. Although woody species density reached a peak in stands from 32 to 56 yr old, rarefaction analysis showed that species richness increased linearly with stand age and was highest in stands 56 yr old or greater. Nonparametric, abundance-based estimators of species richness also showed positive and linear associations with age. Basal area and mean tree height were positively associated with age since abandonment, while sprouting ability showed a negative relationship. Our results indicate rapid recovery of woody species richness and structural characteristics along this tropical dry forest chronosequence

In vitro activity of ceftazidime-avibactam against Gram-negative strains in Chile 2015–2021

ABSTRACT: Objectives: Ceftazidime-avibactam (CAZ-AVI) combines ceftazidime and a reversible β-lactamase inhibitor that has shown activity against multidrug-resistant (MDR) Enterobacterales and P. aeruginosa. Using data from the Antimicrobial Testing Leadership and Surveillance program (ATLAS), this study examined the in vitro antimicrobial activity of CAZ-AVI and other antibiotics against Gram-negative bacteria collected from Chilean hospitals between 2015 and 2021. Methods: Clinical isolates of Enterobacterales and P. aeruginosa were collected from three medical centres in Chile. Blood, abdominal fluid, urine, soft tissues, and respiratory tract samples were obtained from infected patients. Minimum inhibitory concentrations using the broth microdilution method were determined for susceptibility testing, and the Clinical and Laboratory Standards Institute (CLSI) breakpoints were used for interpreting the results. Extended-spectrum β-lactamases (ESBL) and carbapenemase genes were also detected through polymerase chain reaction. Results: A total of 2600 Enterobacterales and 836 P. aeruginosa were analysed. CAZ-AVI was the antibiotic with the highest in vitro activity against Enterobacterales (99.72%). The incidence of carbapenem-resistant Enterobacterales (CRE) was 1.5% (n = 39), and the antibiotics with the best in vitro activity were tigecycline (92.31%), CAZ-AVI (88.57%), and amikacin (79.49%). CAZ-AVI was the antibiotic with the best activity against ESBL-producing Enterobacterales (99.34%) and MDR Enterobacterales (99.31%). For KPC-producing Enterobacterales, susceptibility to amikacin was 100%, whereas susceptibility to CAZ-AVI was 91.67%. Regarding MDR and difficult-to-treat resistance P. aeruginosa, 44.83% and 38.99% were susceptible to CAZ-AVI, respectively. Conclusion: CAZ-AVI shows excellent in vitro activity against Enterobacterales in general, CRE, ESBL-producing Enterobacterales, and KPC-producing Enterobacterales. CAZ-AVI is also an option against MDR P. aeruginosa