28 research outputs found
Extensional orogenic collapse captured by strike-slip tectonics:
The late Paleozoic collision between Gondwana and Laurussia resulted in the polyphase deformation and
magmatism that characterizes the Iberian Massif of the Variscan orogen. In the Central Iberian Zone, initial con-
tinental thickening (D1; folding and thrusting) was followed by extensional orogenic collapse (D2) responsible
for the exhumation of high-grade rocks coeval to the emplacement of granitoids.
This study presents a tectonometamorphic analysis of the Trancoso-Pinhel region (Central Iberian Zone) to ex-
plain the processes in place during the transition froman extension-dominated state (D2) to a compression-dom-
inated one (D3).Wereveal the existence of low-dipping D2 extensional structures later affected by several pulses
of subhorizontal shortening, each of them typified by upright folds and strike-slip shearing (D3, D4 and D5, as
identified by superimposition of structures). The D2 Pinhel extensional shear zone separates a low-grade domain
from an underlying high-grade domain, and it contributed to the thermal reequilibration of the orogen by facil-
itating heat advection from lower parts of the crust, crustal thinning, decompression melting, and magma intru-
sion. Progressive lessening of the gravitational disequilibrium carried out by this D2 shear zone led to a switch
from subhorizontal extension to compression and the eventual cessation and capture of the Pinhel shear zone
by strike-slip tectonics during renewed crustal shortening. High-grade domains of the Pinhel shear zone were
folded together with low-grade domains to define the current upright folded structure of the Trancoso-Pinhel re-
gion, the D3 Tamames-Marofa-SĂĄtĂŁo synform. Newdating of syn-orogenic granitoids (SHRIMP U\\Pb zircon dat-
ing) intruding the Pinhel shear zone, together with the already published ages of early extensional fabrics
constrain the functioning of this shear zone to ca. 331â311 Ma, with maximum tectonomagmatic activity at ca.
321â317 Ma. The capture and apparent cessation of movement of the Pinhel shear zone occurred at ca. 317â
311 Ma
Strike-slip shear zones of the Iberian Massif: Are they coeval?
Strike-slip shear zones of the Variscan orogen are used to derive the evolution of paleostrain and discuss the kinematics of the waning stages
of the Gondwana-Laurussia collision during the amalgamation of Pangea. In the Iberian Massif, the recognition of three late Carboniferous
deformation events related to strike-slip tectonics (D3, D4, D5) in the Trancoso-Pinhel region (Portugal) reveals that late orogenic transcurrent
deformation was episodic and occurred in a short period of time (<15 m.y.). Early stages of strike-slip deformation included dextral and sinistral
shear zones and orogen-parallel upright folds (D3; ca. 311 Ma). These structures followed the development of extensional shear zones (D2) during
the tectonothermal reequilibration of the orogen. D3 structures were deflected and folded by the sinistral D4 Juzbado-Penalva do Castelo
shear zone, dated as ca. 309â305 Ma by SHRIMP (sensitive high-resolution ion microprobe) U-Pb zircon dating of synkinematic granitoids.
D3 and D4 structures were folded under east-west compression (D5) influenced by the strike-slip movement of the dextral Porto-Tomar shear
zone. Variscan movement along the Porto-Tomar shear zone started ca. 304 Ma (onset of the Buçaco basin and syn-D5 granites), but ceased
before ca. 295 Ma (age of the final closure of the Ibero-Armorican arc and crosscutting granites). The contrasting geometry, kinematics, and
timing of these strike-slip shear zones are explained by deformation partitioning upon a rheologically inhomogeneous crust with structural
and tectonothermal anisotropies generated during previous deformation. The convergence vector between Gondwana and Laurussia during
D3âD5 remained the same, and was equivalent to the vector that explains the previous tectonic record (D2) in central and northwestern Iberia
Peralkaline and alkaline magmatism of the Ossa-Morena Zone (SW Iberia): age, source and implications for the Paleozoic evolution of Gondwanan lithosphere
The Ossa-Morena zone in SW Iberia represents a section of the northern margin of West Gondwana that formed part of a Cordilleran-type
orogenic system during the Neoproterozoic (Cadomian orogeny). The crustal section in this zone preserves the record of rifting that led to
the opening of the Rheic Ocean in the early Paleozoic and the collision of Gondwana and Laurussia in the late Paleozoic (Variscan orogeny).
We present U-Pb zircon data from three alkaline to peralkaline syenites that intruded Neoproterozoic and Cambrian strata and give
crystallization ages ranging between ca. 490 Ma and 470 Ma. Lu/Hf isotopic data from these zircons give positive initial eHf values (0 †eHf(t) â€
+11.5) that approach the model values for the depleted mantle at the time of crystallization. This suggests that a significant proportion of the
magma was derived from the mantle, with limited mixing/assimilation with crustal-derived melts. Alkaline/peralkaline magmatic suites of
similar age and chemical composition intruded other sections of the northern margin of West Gondwana and along the boundaries of the
continental blocks that today make up Iberia. These blocks are further characterized by the presence of high-pressure metamorphic belts
that formed during accretion and subsequent collision of peri-Gondwanan domains against Laurussia during the Devonian and Carboniferous
(Variscan orogeny). Our U-Pb and Lu-Hf data set indicates that during the CambrianâOrdovician transition, lithosphere extension
reached a stage of narrow intracontinental rifting, where deeply sourced magmas, probably coming from the lower crust and/or the upper
mantle, intruded continental upper crust across various sections of previously stretched crust. We propose that necking of the Gondwana
lithosphere into several continental microblocks with fertile mantle beneath them compartmentalized extension (multiblock model), which
favored the onset of early Paleozoic peralkaline and alkaline magmas. The boundaries of microblocks represent zones of inherited crustal
weakness that were later reactivated during the late Paleozoic as major accretionary faults related to the amalgamation of Pangea during
the Variscan orogeny. Our dynamic model provides an explanation for the unusual spatial relationship between peralkaline and alkaline
igneous provinces (usually shallow in the crust) and the occurrence of high-pressure rocks. Our observations suggest that Cordilleran-type
orogens subjected to extension after long-lived subduction can develop wide continental platforms that feature multiple continental blocks.
In addition, the formation of sequenced high-pressure belts in collisional orogens can be explained as the ultimate consequence of multiple
necking events within continental lithosphere during previous collapse of a Cordilleran-type orogen
Tectonic evolution of Variscan Iberia: GondwanaâLaurussia
An integrated interpretation of the late Paleozoic structural and geochronological record of the Iberian Massif is
presented and discussed under the perspective of a Gondwana-Laurussia collision giving way to the Variscan
orogen. Compressional and extensional structures developed during the building of the Variscan orogenic crust
of Iberia are linked together into major tectonic events operating at lithosphere scale. A review of the
tectonometamorphic and magmatic evolution of the IberianMassif reveals backs and forths in the overall conver-
gence between Gondwana and Laurussia during theamalgamation of Pangea in late Paleozoic times. Stages dom-
inated by lithosphere compression are characterized by subduction, both oceanic and continental, development
of magmatic arcs, (over- and under-) thrusting of continental lithosphere, and folding. Variscan convergence re-
sulted in the eventual transference of a large allochthonous set of peri-Gondwanan terranes, the Iberian
Allochthon, onto the Gondwana mainland. The Iberian Allochthon bears the imprint of previous interaction be-
tween Gondwana and Laurussia, including their juxtaposition after the closure of the Rheic Ocean in Lower De-
vonian times. Stages governed by lithosphere extension are featured by the opening of two short-lived oceanic
basins that dissected previous Variscan orogenic crust, first in the Lower-Middle Devonian, following the closure
of the Rheic Ocean, and then in the early Carboniferous, following the emplacement of the peri-Gondwanan
allochthon. An additional, major intra-orogenic extensional event in the early-middle Carboniferous dismem-
bered the Iberian Allochthon into individual thrust stacks separated by extensional faults and domes. Lateral tec-
tonics played an important role through the Variscan orogenesis, especially during the creation of new tectonic
blocks separated by intracontinental strike-slip shear zones in the late stages of continental convergence
Identification of MRP4/ABCC4 as a target for reducing the proliferation of pancreatic ductal adenocarcinoma cells by modulating the cAMP efflux
Pancreatic cancer is one of the most lethal types of tumors with no effective therapy available; is currently the third leading cause of cancer in developed countries; and is predicted to become the second deadliest cancer in the United States by 2030. Due to the marginal benefits of current standard chemotherapy, the identification of new therapeutic targets is greatly required. Considering that cAMP pathway is commonly activated in pancreatic ductal adenocarcinoma (PDAC) and its premalignant lesions, we aim to investigate the multidrug resistance-associated protein 4 (MRP4)-dependent cAMP extrusion process as a cause of increased cell proliferation in human PDAC cell lines. Our results from in silico analysis indicate that MRP4 expression may influence PDAC patient outcome; thus, high MRP4 levels could be indicators of poor survival. In addition, we performed in vitro experiments and identified an association between higher MRP4 expression levels and more undifferentiated and malignant models of PDAC and cAMP extrusion capacity. We studied the antiproliferative effect and the overall cAMP response of three MRP4 inhibitors, probenecid, MK571, and ceefourin-1 in PDAC in vitro models. Moreover, MRP4-specific silencing in PANC-1 cells reduced cell proliferation (P, 0.05), whereas MRP4 overexpression in BxPC-3 cells significantly incremented their growth rate in culture (P, 0.05). MRP4 pharmacological inhibition or silencing abrogated cell proliferation through the activation of the cAMP/Epac/Rap1 signaling pathway. Also, extracellular cAMP reverted the antiproliferative effect of MRP4 blockade. Our data highlight the MRP4-dependent cAMP extrusion process as a key participant in cell proliferation, indicating that MRP4 could be an exploitable therapeutic target for PDAC.Fil: Carozzo, Alejandro Enrique. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Yaneff, AgustĂn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Gomez, Natalia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Di Siervi, NicolĂĄs. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Sahores, Ana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Diez, Federico Ruben. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Attorresi, Alejandra InĂ©s. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Instituto de InvestigaciĂłn en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Rodriguez Gonzalez, Angela Paola. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Monczor, Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Fernandez, Natalia Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; ArgentinaFil: Abba, MartĂn Carlos. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Shayo, Carina Claudia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental. FundaciĂłn de Instituto de BiologĂa y Medicina Experimental. Instituto de BiologĂa y Medicina Experimental; ArgentinaFil: Davio, Carlos Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones FarmacolĂłgicas. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de Investigaciones FarmacolĂłgicas; Argentin
Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study
Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.
Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.
Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05â2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001).
Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
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Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9â27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6â16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2â1.8), stage II (OR 1.6; 95% CI 1.4â1.9), and stage III or worse (OR 2.8; 95% CI 2.3â3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
The original version of this article unfortunately contained a mistake
Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9â27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6â16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2â1.8), stage II (OR 1.6; 95% CI 1.4â1.9), and stage III or worse (OR 2.8; 95% CI 2.3â3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTICâHF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTICâHF) trial. Here we describe the baseline characteristics of participants in GALACTICâHF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA)ââ„âII, EF â€35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokineticâguided dosing: 25, 37.5 or 50âmg bid). 8256 patients [male (79%), nonâwhite (22%), mean age 65âyears] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NTâproBNP 1971âpg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTICâHF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressureâ<â100âmmHg (n = 1127), estimated glomerular filtration rate <â30âmL/min/1.73 m2 (n = 528), and treated with sacubitrilâvalsartan at baseline (n = 1594).
Conclusions:
GALACTICâHF enrolled a wellâtreated, highârisk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation