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1.
N Engl J Med ; 390(18): 1663-1676, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38657265

RESUMEN

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis through ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of the erythroid-specific enhancer region of BCL11A in autologous CD34+ hematopoietic stem and progenitor cells (HSPCs). METHODS: We conducted an open-label, single-group, phase 3 study of exa-cel in patients 12 to 35 years of age with transfusion-dependent ß-thalassemia and a ß0/ß0, ß0/ß0-like, or non-ß0/ß0-like genotype. CD34+ HSPCs were edited by means of CRISPR-Cas9 with a guide mRNA. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was transfusion independence, defined as a weighted average hemoglobin level of 9 g per deciliter or higher without red-cell transfusion for at least 12 consecutive months. Total and fetal hemoglobin concentrations and safety were also assessed. RESULTS: A total of 52 patients with transfusion-dependent ß-thalassemia received exa-cel and were included in this prespecified interim analysis; the median follow-up was 20.4 months (range, 2.1 to 48.1). Neutrophils and platelets engrafted in each patient. Among the 35 patients with sufficient follow-up data for evaluation, transfusion independence occurred in 32 (91%; 95% confidence interval, 77 to 98; P<0.001 against the null hypothesis of a 50% response). During transfusion independence, the mean total hemoglobin level was 13.1 g per deciliter and the mean fetal hemoglobin level was 11.9 g per deciliter, and fetal hemoglobin had a pancellular distribution (≥94% of red cells). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No deaths or cancers occurred. CONCLUSIONS: Treatment with exa-cel, preceded by myeloablation, resulted in transfusion independence in 91% of patients with transfusion-dependent ß-thalassemia. (Supported by Vertex Pharmaceuticals and CRISPR Therapeutics; CLIMB THAL-111 ClinicalTrials.gov number, NCT03655678.).


Asunto(s)
Hemoglobina Fetal , Edición Génica , Trasplante de Células Madre Hematopoyéticas , Talasemia beta , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Adulto Joven , Antígenos CD34 , Talasemia beta/terapia , Talasemia beta/genética , Transfusión Sanguínea , Busulfano/uso terapéutico , Sistemas CRISPR-Cas , Hemoglobina Fetal/biosíntesis , Hemoglobina Fetal/genética , Edición Génica/métodos , Trasplante de Células Madre Hematopoyéticas/métodos , Células Madre Hematopoyéticas , Proteínas Represoras/genética , Acondicionamiento Pretrasplante , Trasplante Autólogo , Agonistas Mieloablativos/uso terapéutico , América del Norte , Europa (Continente)
2.
N Engl J Med ; 390(18): 1649-1662, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38661449

RESUMEN

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis by means of ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of BCL11A. METHODS: We conducted a phase 3, single-group, open-label study of exa-cel in patients 12 to 35 years of age with sickle cell disease who had had at least two severe vaso-occlusive crises in each of the 2 years before screening. CD34+ HSPCs were edited with the use of CRISPR-Cas9. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was freedom from severe vaso-occlusive crises for at least 12 consecutive months. A key secondary end point was freedom from inpatient hospitalization for severe vaso-occlusive crises for at least 12 consecutive months. The safety of exa-cel was also assessed. RESULTS: A total of 44 patients received exa-cel, and the median follow-up was 19.3 months (range, 0.8 to 48.1). Neutrophils and platelets engrafted in each patient. Of the 30 patients who had sufficient follow-up to be evaluated, 29 (97%; 95% confidence interval [CI], 83 to 100) were free from vaso-occlusive crises for at least 12 consecutive months, and all 30 (100%; 95% CI, 88 to 100) were free from hospitalizations for vaso-occlusive crises for at least 12 consecutive months (P<0.001 for both comparisons against the null hypothesis of a 50% response). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No cancers occurred. CONCLUSIONS: Treatment with exa-cel eliminated vaso-occlusive crises in 97% of patients with sickle cell disease for a period of 12 months or more. (CLIMB SCD-121; ClinicalTrials.gov number, NCT03745287.).


Asunto(s)
Anemia de Células Falciformes , Hemoglobina Fetal , Trasplante de Células Madre Hematopoyéticas , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Adulto Joven , Anemia de Células Falciformes/complicaciones , Anemia de Células Falciformes/genética , Anemia de Células Falciformes/terapia , Antígenos CD34 , Busulfano/uso terapéutico , Sistemas CRISPR-Cas , Hemoglobina Fetal/biosíntesis , Hemoglobina Fetal/genética , Edición Génica , Células Madre Hematopoyéticas , Proteínas Represoras , Acondicionamiento Pretrasplante , Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Agonistas Mieloablativos/uso terapéutico , Europa (Continente) , América del Norte
3.
Proc Natl Acad Sci U S A ; 120(12): e2212867120, 2023 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-36913594

RESUMEN

In 2004 through 2016, three studies in the national Midlife in the United States (MIDUS) project asked participants the open-ended question "What do you do to make life go well?". We use verbatim responses to this question to evaluate the relative importance of psychological traits and circumstances for predicting self-reported, subjective well-being. The use of an open-ended question allows us to test the hypothesis that psychological traits are more strongly associated with self-reported well-being than objective circumstances because psychological traits and well-being are similarly self-rated-meaning that they both ask respondents to decide how to place themselves on provided and unfamiliar survey scales. For this, we use automated zero-shot classification to score statements about well-being without training on existing survey measures, and we evaluate this scoring through subsequent hand-labeling. We then assess associations of this measure and closed-ended measures for health behaviors, socioeconomic circumstances, biomarkers for inflammation and glycemic control, and mortality risk over follow-up. Although the closed-ended measures were far more strongly associated with other multiple-choice self-ratings, including Big 5 personality traits, the closed- and open-ended measures were similarly associated with relatively objective indicators of health, wealth, and social connectedness. The findings suggest that psychological traits, when collected through self-ratings, predict subjective reports of well-being so strongly because of a measurement advantage-and that circumstance matters just as much when assessed using a fairer comparison.


Asunto(s)
Conductas Relacionadas con la Salud , Inflamación , Humanos , Estados Unidos , Encuestas y Cuestionarios , Autoinforme , Biomarcadores
4.
Proc Natl Acad Sci U S A ; 119(34): e2115900119, 2022 08 23.
Artículo en Inglés | MEDLINE | ID: mdl-35972960

RESUMEN

Following the 2020 general election, Republican elected officials, including then-President Donald Trump, promoted conspiracy theories claiming that Joe Biden's close victory in Georgia was fraudulent. Such conspiratorial claims could implicate participation in the Georgia Senate runoff election in different ways-signaling that voting doesn't matter, distracting from ongoing campaigns, stoking political anger at out-partisans, or providing rationalizations for (lack of) enthusiasm for voting during a transfer of power. Here, we evaluate the possibility of any on-average relationship with turnout by combining behavioral measures of engagement with election conspiracies online and administrative data on voter turnout for 40,000 Twitter users registered to vote in Georgia. We find small, limited associations. Liking or sharing messages opposed to conspiracy theories was associated with higher turnout than expected in the runoff election, and those who liked or shared tweets promoting fraud-related conspiracy theories were slightly less likely to vote.


Asunto(s)
Comunicación , Fraude , Política , Georgia , Humanos , Estudios Longitudinales
5.
Proc Natl Acad Sci U S A ; 119(4)2022 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-35046018

RESUMEN

Crisis motivates people to track news closely, and this increased engagement can expose individuals to politically sensitive information unrelated to the initial crisis. We use the case of the COVID-19 outbreak in China to examine how crisis affects information seeking in countries that normally exert significant control over access to media. The crisis spurred censorship circumvention and access to international news and political content on websites blocked in China. Once individuals circumvented censorship, they not only received more information about the crisis itself but also accessed unrelated information that the regime has long censored. Using comparisons to democratic and other authoritarian countries also affected by early outbreaks, the findings suggest that people blocked from accessing information most of the time might disproportionately and collectively access that long-hidden information during a crisis. Evaluations resulting from this access, negative or positive for a government, might draw on both current events and censored history.


Asunto(s)
Acceso a la Información , COVID-19/psicología , Conducta en la Búsqueda de Información/fisiología , Acceso a la Información/legislación & jurisprudencia , Acceso a la Información/psicología , COVID-19/epidemiología , China/epidemiología , Humanos , Sistemas Políticos , Política , SARS-CoV-2 , Medios de Comunicación Sociales/legislación & jurisprudencia , Medios de Comunicación Sociales/estadística & datos numéricos , Medios de Comunicación Sociales/tendencias
6.
N Engl J Med ; 384(14): 1323-1334, 2021 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-33826820

RESUMEN

BACKGROUND: Cold agglutinin disease is a rare autoimmune hemolytic anemia characterized by hemolysis that is caused by activation of the classic complement pathway. Sutimlimab, a humanized monoclonal antibody, selectively targets the C1s protein, a C1 complex serine protease responsible for activating this pathway. METHODS: We conducted a 26-week multicenter, open-label, single-group study to assess the efficacy and safety of intravenous sutimlimab in patients with cold agglutinin disease and a recent history of transfusion. The composite primary end point was a normalization of the hemoglobin level to 12 g or more per deciliter or an increase in the hemoglobin level of 2 g or more per deciliter from baseline, without red-cell transfusion or medications prohibited by the protocol. RESULTS: A total of 24 patients were enrolled and received at least one dose of sutimlimab; 13 patients (54%) met the criteria for the composite primary end point. The least-squares mean increase in hemoglobin level was 2.6 g per deciliter at the time of treatment assessment (weeks 23, 25, and 26). A mean hemoglobin level of more than 11 g per deciliter was maintained in patients from week 3 through the end of the study period. The mean bilirubin levels normalized by week 3. A total of 17 patients (71%) did not receive a transfusion from week 5 through week 26. Clinically meaningful reductions in fatigue were observed by week 1 and were maintained throughout the study. Activity in the classic complement pathway was rapidly inhibited, as assessed by a functional assay. Increased hemoglobin levels, reduced bilirubin levels, and reduced fatigue coincided with inhibition of the classic complement pathway. At least one adverse event occurred during the treatment period in 22 patients (92%). Seven patients (29%) had at least one serious adverse event, none of which were determined by the investigators to be related to sutimlimab. No meningococcal infections occurred. CONCLUSIONS: In patients with cold agglutinin disease who received sutimlimab, selective upstream inhibition of activity in the classic complement pathway rapidly halted hemolysis, increased hemoglobin levels, and reduced fatigue. (Funded by Sanofi; CARDINAL ClinicalTrials.gov number, NCT03347396.).


Asunto(s)
Anemia Hemolítica Autoinmune/tratamiento farmacológico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Complemento C1s/antagonistas & inhibidores , Anciano , Anciano de 80 o más Años , Anemia Hemolítica Autoinmune/sangre , Anemia Hemolítica Autoinmune/complicaciones , Anemia Hemolítica Autoinmune/terapia , Anticuerpos Monoclonales Humanizados/efectos adversos , Anticuerpos Monoclonales Humanizados/farmacología , Transfusión Sanguínea , Fatiga/tratamiento farmacológico , Fatiga/etiología , Femenino , Hemoglobinas/análisis , Hemólisis/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida
7.
Am J Hematol ; 99(3): 430-438, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38010293

RESUMEN

A growing number of gene therapy- and gene editing-based treatments for patients with sickle cell disease (SCD) are entering clinical trials. These treatments, designed to target the underlying cause of SCD, have the potential to provide functional cures, which until now were possible only through allogeneic hematopoietic stem cell transplant. However, as these novel approaches advance from early- to late-stage clinical trials, it is essential to identify physiologically and clinically relevant endpoints that can demonstrate the achievement of a functional cure for SCD. Here, we present an overview of the pathophysiology of SCD and current treatment options, review ongoing SCD clinical trials using gene therapy or gene editing approaches, and identify the most relevant endpoints for demonstrating the attainment of a functional cure for SCD.


Asunto(s)
Anemia de Células Falciformes , Trasplante de Células Madre Hematopoyéticas , Humanos , Edición Génica , Anemia de Células Falciformes/genética , Anemia de Células Falciformes/terapia , Terapia Genética
8.
Am J Hematol ; 99(3): 422-429, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38100154

RESUMEN

ß-thalassemia is a monogenic disease that results in varying degrees of anemia. In the most severe form, known as transfusion-dependent ß-thalassemia (TDT), the clinical hallmarks are ineffective erythropoiesis and a requirement of regular, life-long red blood cell transfusions, with the development of secondary clinical complications such as iron overload, end-organ damage, and a risk of early mortality. With the exception of allogeneic hematopoietic cell transplantation, current treatments for TDT address disease symptoms and not the underlying cause of disease. Recently, a growing number of gene addition and gene editing-based treatments for patients with TDT with the potential to provide a one-time functional cure have entered clinical trials. A key challenge in the design and evaluation of these trials is selecting endpoints to evaluate if these novel genetic therapies have a curative versus an ameliorative effect. Here, we present an overview of the pathophysiology of TDT, review emerging gene addition or gene editing therapeutic approaches for TDT currently in clinical trials, and identify a series of endpoints that can quantify therapeutic effects, including a curative outcome.


Asunto(s)
Talasemia beta , Humanos , Talasemia beta/genética , Talasemia beta/terapia , Edición Génica , Transfusión Sanguínea , Transfusión de Eritrocitos/efectos adversos , Terapia Genética/métodos
9.
Ann Hematol ; 101(10): 2169-2177, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35999387

RESUMEN

Patients with cold agglutinin disease (CAD) experience fatigue and poor quality of life. However, previous CAD-related studies have not explored patient-reported outcomes such as the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue. Sutimlimab, a C1s complement inhibitor, has been shown to halt haemolysis in CAD. Here, we present 26-weeks' patient-reported data from CARDINAL Part A (ClinicalTrials.gov, NCT03347396), which assessed efficacy and safety of sutimlimab in patients with CAD and recent history of transfusion. Aside from measuring changes in haemolytic markers, FACIT-Fatigue was measured at the treatment assessment timepoint (TAT; average of weeks 23, 25, and 26). Exploratory endpoints included the change in EuroQol 5-dimension 5-level questionnaire (EQ-5D-5L) and the 12-Item Short Form Health Survey (SF-12) at TAT, and Patient Global Impression of Change (PGIC), and Patient Global Impression of (fatigue) Severity (PGIS) at week 26. Mean (range) FACIT-Fatigue scores increased from 32.5 (14.0-47.0) at baseline (a score indicative of severe fatigue) to 44.3 (28.0-51.0) at TAT. Considerable improvements were reported for EQ-5D-5L at TAT, SF-12 scores at TAT, and PGIC and PGIS scores at week 26. Sutimlimab treatment resulted in sustained improvements in symptoms of fatigue and overall quality of life in patients with CAD. NCT03347396. Registered 20 November, 2017.


Asunto(s)
Anemia Hemolítica Autoinmune , Calidad de Vida , Anemia Hemolítica Autoinmune/tratamiento farmacológico , Anticuerpos Monoclonales Humanizados , Fatiga/etiología , Humanos , Medición de Resultados Informados por el Paciente , Resultado del Tratamiento
11.
Environ Sci Technol ; 53(19): 11102-11111, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31460753

RESUMEN

Biofilms, composed of periphyton, bacteria, and organic detritus, are the base of the food web in many streams and rivers. This media adsorbs and actively sequesters organic and inorganic contaminants from the water column. Here, we demonstrate the utility of using the contaminant concentrations in the biofilm matrix as an environmental media in source tracking and understanding biological impacts at higher trophic levels. Physical partitioning of polychlorinated biphenyl (PCB) and polybrominated diphenyl ether congeners is the dominant mode of uptake from water to biofilm and bioaccumulation factor: log Kow relationships suggest that PCB uptake is often near equilibrium between log Kow 5-7. We show that the concentrations of metals in biofilms are more effective at delineating and recording spatial and temporal differences in metal inputs than bed sediments and water samples. The burden of metals in the biofilm matrix explained adverse impacts and variability in periphyton metrics and ecological integrity in macroinvertebrates. This work provides new insights into the partitioning of organic chemicals onto biofilms and shows clear linkages between metals in the biofilm matrix and ecological health of invertebrates that depend on biofilms as a food source.


Asunto(s)
Bifenilos Policlorados , Contaminantes Químicos del Agua , Animales , Biopelículas , Monitoreo del Ambiente , Agua Dulce , Sedimentos Geológicos , Ríos
12.
Proc Natl Acad Sci U S A ; 113(46): 12980-12984, 2016 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-27799553

RESUMEN

Social interactions increasingly take place online. Friendships and other offline social ties have been repeatedly associated with human longevity, but online interactions might have different properties. Here, we reference 12 million social media profiles against California Department of Public Health vital records and use longitudinal statistical models to assess whether social media use is associated with longer life. The results show that receiving requests to connect as friends online is associated with reduced mortality but initiating friendships is not. Additionally, online behaviors that indicate face-to-face social activity (like posting photos) are associated with reduced mortality, but online-only behaviors (like sending messages) have a nonlinear relationship, where moderate use is associated with the lowest mortality. These results suggest that online social integration is linked to lower risk for a wide variety of critical health problems. Although this is an associational study, it may be an important step in understanding how, on a global scale, online social networks might be adapted to improve modern populations' social and physical health.


Asunto(s)
Relaciones Interpersonales , Mortalidad , Adulto , California/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Riesgo , Medios de Comunicación Sociales , Red Social
14.
Ecol Appl ; 27(7): 2155-2169, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28692788

RESUMEN

Research on lake eutrophication often identifies variables affecting amounts of phosphorus (P) and nitrogen (N) in lakes, but understanding factors influencing N:P ratios is important given its influence on species composition and toxin production by cyanobacteria. We sampled 80 shallow lakes in Minnesota (USA) for three years to assess effects of watershed size, proportion of watershed as both row crop and natural area, fish biomass, and lake alternative state (turbid vs. clear) on total N : total P (TN : TP), ammonium, total dissolved phosphorus (TDP), and seston stoichiometry. We also examined N:P stoichiometry in 20 additional lakes that shifted states during the study. Last, we assessed the importance of denitrification by measuring denitrification rates in sediment cores from a subset of 34 lakes, and by measuring seston δ15 N in four additional experimental lakes before and after they were experimentally manipulated from turbid to clear states. Results showed alternative state had the largest influence on overall N:P stoichiometry in these systems, as it had the strongest relationship with TN : TP, seston C:N:P, ammonium, and TDP. Turbid lakes had higher N at given levels of P than clear lakes, with TN and ammonium 2-fold and 1.4-fold higher in turbid lakes, respectively. In lakes that shifted states, TN was 3-fold higher in turbid lakes, while TP was only 2-fold higher, supporting the notion N is more responsive to state shifts than is P. Seston δ15 N increased after lakes shifted to clear states, suggesting higher denitrification rates may be important for reducing N levels in clear states, and potential denitrification rates in sediment cores were among the highest recorded in the literature. Overall, our results indicate lake state was a primary driver of N:P dynamics in shallow lakes, and lakes in clear states had much lower N at a given level of P relative to turbid lakes, likely due to higher denitrification rates. Shallow lakes are often managed for the clear-water state due to increased value as wildlife habitat. However, our results indicate lake state also influences N biogeochemistry, such that managing shallow lakes for the clear-water state may also mitigate excess N levels at a landscape scale.


Asunto(s)
Desnitrificación , Lagos/química , Nitrógeno/química , Fósforo/química , Animales , Biomasa , Eutrofización , Peces , Minnesota
15.
Br J Haematol ; 174(6): 970-82, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27291690

RESUMEN

Very Late Antigen-4 (VLA-4, α4ß1-integrin, ITGA4) orchestrates cell-cell and cell-endothelium adhesion. Given the proposed role of VLA-4 in sickle cell disease (SCD) pathophysiology, we evaluated the ability of the VLA-4 blocking antibody natalizumab to inhibit SCD blood cell adhesion. Natalizumab recognized surface VLA-4 on leucocytes and reticulocytes in whole blood from SCD subjects. SCD reticulocytes were positive for VLA-4, while VLA-4 staining of non-SCD reticulocytes was undetectable. Titrations with natalizumab revealed the presence of saturable levels of VLA-4 on both SCD reticulocytes and leucocytes similar to healthy subject leucocytes. Under physiological flow conditions, the adhesion of SCD whole blood cells and isolated SCD leucocytes to immobilized vascular cell adhesion molecule 1 (VCAM-1) was blocked by natalizumab in a dose-dependent manner, which correlated with cell surface receptor binding. Natalizumab also inhibited >50% of whole blood cell binding to TNF-α activated human umbilical vein endothelial cell monolayers under physiological flow at clinically relevant concentrations (10 to 100 µg/ml). This indicates that VLA-4 is the dominant receptor that drives SCD reticulocyte and mononuclear cell adhesion to VCAM-1 and that the VLA-4 adhesion to VCAM-1 is a significant contributor to SCD blood cell adhesion to endothelium. Thus, VLA-4 blockade may be beneficial in sickle cell disease.


Asunto(s)
Anemia de Células Falciformes/sangre , Adhesión Celular/efectos de los fármacos , Integrina alfa4beta1/antagonistas & inhibidores , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Natalizumab/farmacología , Reticulocitos/efectos de los fármacos , Reticulocitos/patología , Adolescente , Adulto , Anemia de Células Falciformes/diagnóstico , Anemia de Células Falciformes/tratamiento farmacológico , Biomarcadores , Membrana Celular/metabolismo , Niño , Preescolar , Simulación por Computador , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Femenino , Citometría de Flujo , Hemodinámica , Humanos , Inmunoglobulina G/química , Inmunoglobulina G/metabolismo , Inmunoglobulina G/farmacología , Lactante , Masculino , Persona de Mediana Edad , Natalizumab/química , Natalizumab/metabolismo , Unión Proteica , Multimerización de Proteína , Reticulocitos/metabolismo , Molécula 1 de Adhesión Celular Vascular/metabolismo , Adulto Joven
16.
Ecol Appl ; 26(8): 2660-2674, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27907264

RESUMEN

Ecological shifts in shallow lakes from clear-water macrophyte-dominated to turbid-water phytoplankton-dominated are generally thought of as rapid short-term transitions. Diatom remains in sediment records from shallow lakes in the Prairie Pothole Region of North America provide new evidence that the long-term ecological stability of these lakes is defined by the legacy of large regime shifts. We examine the modern and historical stability of 11 shallow lakes. Currently, four of the lakes are in a clear-water state, three are consistently turbid-water, and four have been observed to change state from year to year (transitional). Lake sediment records spanning the past 150-200 yr suggest that (1) the diatom assemblage is characteristic of either clear or turbid lakes, (2) prior to significant landscape alteration, all of the lakes existed in a regime of a stable clear-water state, (3) lakes that are currently classified as turbid or transitional have experienced one strong regime shift over the past 150-200 yr and have since remained in a regime where turbid-water predominates, and (4) top-down impacts to the lake food-web from fish introductions appear to be the dominant driver of strong regime shifts and not increased nutrient availability. Based on our findings we demonstrate a method that could be used by lake managers to identify lakes that have an ecological history close to the clear-turbid regime threshold; such lakes might more easily be returned to a clear-water state through biomanipulation. The unfortunate reality is that many of these lakes are now part of a managed landscape and will likely require continued intervention.


Asunto(s)
Cadena Alimentaria , Fitoplancton , Animales , Ecosistema , Lagos , América del Norte
17.
Arterioscler Thromb Vasc Biol ; 33(6): 1230-7, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23539221

RESUMEN

OBJECTIVE: Cocaine use is associated with arterial thrombosis, including myocardial infarction and stroke. Cocaine use results in increased plasma von Willebrand factor (VWF), accelerated atherosclerosis, and platelet-rich arterial thrombi, suggesting that cocaine activates the endothelium, promoting platelet-VWF interactions. APPROACH AND RESULTS: Human umbilical vein endothelial cells, brain microvasculature endothelial cells, or coronary artery endothelial cells were treated with cocaine or metabolites benzoylecgonine, cocaethylene, norcocaine, or ecgonine methylester. Supernatant VWF concentration and multimer structure were measured, and platelet-VWF strings formed on the endothelial surface under flow were quantified. Cocaine, benzoylecgonine, and cocaethylene induced endothelial VWF release, with the 2 metabolites being more potent than the parent molecule. Brain microvasculature endothelial cells were more sensitive to cocaine and metabolites than were human umbilical vein endothelial cells or coronary artery endothelial cells. Coronary artery endothelial cells released VWF into the supernatant but did not form VWF-platelet strings. Intracellular cAMP concentration was not increased after treatment with cocaine or its metabolites. CONCLUSIONS: Both cocaine and metabolites benzoylecgonine and cocaethylene induced endothelial VWF secretion, possibly explaining thrombotic risk after cocaine ingestion. VWF secretion is likely to vary between vascular beds, with brain endothelial cells being particularly sensitive. These results suggest that clinical management of cocaine-induced ischemia may benefit from therapies aimed at disrupting the VWF-platelet interaction.


Asunto(s)
Cocaína/análogos & derivados , Cocaína/farmacología , Células Endoteliales/efectos de los fármacos , Selectina-P/efectos de los fármacos , Factor de von Willebrand/efectos de los fármacos , Encéfalo/citología , Células Cultivadas , Vasos Coronarios/citología , Vasos Coronarios/efectos de los fármacos , Células Endoteliales/metabolismo , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Técnicas In Vitro , Selectina-P/metabolismo , Sensibilidad y Especificidad , Trombosis/fisiopatología , Factor de von Willebrand/metabolismo
18.
Blood ; 117(13): 3680-3, 2011 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-21300978

RESUMEN

Vaso-occlusion, hemolysis, and oxidative stress are hallmarks of sickle cell disease (SCD). This pathology is accompanied by systemic endothelial activation, rendering the endothelium more adhesive for blood cells, including sickle erythrocytes. Activated endothelial cells display or secrete several adhesive molecules, including von Willebrand factor (VWF). We assessed several VWF parameters in SCD patients at baseline: multimer pattern, antigen concentration (VWF:Ag), activation factor (VWF:AF), and total active VWF (VWF:TA). VWF:AF was determined using a llama nanobody (AU/VWFa-11) that detects a platelet-binding conformation of the A1 domain; VWF:TA was calculated by multiplying VWF:Ag by VWF:AF. SCD plasma contained elevated VWF:Ag and ultralarge VWF multimers. VWF:TA, a measure of total VWF reactivity, correlated closely with hemolysis, as determined by serum lactate dehydrogenase. ADAMTS13 activity and antigen were normal in all patients. These findings suggest an important role for hyperreactive VWF in SCD pathology and connect SCD to other microangiopathies, particularly thrombotic thrombocytopenic purpura.


Asunto(s)
Anemia de Células Falciformes/sangre , Anemia de Células Falciformes/patología , Hemólisis/fisiología , Factor de von Willebrand/metabolismo , Proteínas ADAM/sangre , Proteínas ADAM/metabolismo , Proteína ADAMTS13 , Adulto , Anemia de Células Falciformes/metabolismo , Análisis Químico de la Sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Peso Molecular , Complejos Multiproteicos/análisis , Complejos Multiproteicos/sangre , Complejos Multiproteicos/metabolismo , Plasma/química , Multimerización de Proteína , Adulto Joven , Factor de von Willebrand/análisis
19.
Proc Natl Acad Sci U S A ; 107(50): 21343-8, 2010 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-21149690

RESUMEN

Humans have altered natural patterns of fire for millennia, but the impact of human-set fires is thought to have been slight in wet closed-canopy forests. In the South Island of New Zealand, Polynesians (Maori), who arrived 700-800 calibrated years (cal y) ago, and then Europeans, who settled ∼150 cal y ago, used fire as a tool for forest clearance, but the structure and environmental consequences of these fires are poorly understood. High-resolution charcoal and pollen records from 16 lakes were analyzed to reconstruct the fire and vegetation history of the last 1,000 y. Diatom, chironomid, and element concentration data were examined to identify disturbance-related limnobiotic and biogeochemical changes within burned watersheds. At most sites, several high-severity fire events occurred within the first two centuries of Maori arrival and were often accompanied by a transformation in vegetation, slope stability, and lake chemistry. Proxies of past climate suggest that human activity alone, rather than unusually dry or warm conditions, was responsible for this increased fire activity. The transformation of scrub to grassland by Europeans in the mid-19th century triggered further, sometimes severe, watershed change, through additional fires, erosion, and the introduction of nonnative plant species. Alteration of natural disturbance regimes had lasting impacts, primarily because native forests had little or no previous history of fire and little resilience to the severity of burning. Anthropogenic burning in New Zealand highlights the vulnerability of closed-canopy forests to novel disturbance regimes and suggests that similar settings may be less resilient to climate-induced changes in the future.


Asunto(s)
Clima , Ecosistema , Incendios/historia , Geografía , Animales , Carbón Orgánico , Agua Dulce , Historia Antigua , Humanos , Nueva Zelanda
20.
Blood Adv ; 7(6): 987-996, 2023 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-35973190

RESUMEN

Chronic/refractory immune thrombocytopenia (ITP) is a rare and pathophysiologically heterogeneous disorder with variable responsiveness to available treatments. Sutimlimab, a first-in-class humanized monoclonal anti-C1s IgG4 antibody, selectively inhibits the classical pathway. This phase 1 study (NCT03275454) assessed the safety, efficacy, pharmacokinetics, and pharmacodynamics of biweekly sutimlimab in patients with chronic/refractory ITP with an inadequate response to ≥2 therapies (platelet count ≤ 30 × 109/L). Twelve patients (median age 42 years) received sutimlimab for a median of 20.5 weeks followed by a median 2-week washout period (part A). In part B, 7 of the 12 eligible patients received sutimlimab retreatment for a median of 113 weeks. In part A, the mean (standard deviation) platelet count increased from 25 × 109/L (17) to 54 × 109/L (60) 24 hours after starting sutimlimab, maintaining ≥50 × 109/L throughout part A. Five patients (42%) achieved durable platelet count responses (≥50 × 109/L in ≥50% of follow-up visits) and 4 achieved complete response (platelet count ≥100 × 109/L). The mean platelet count returned to baseline during washout and increased upon retreatment in part B. The mean platelet count improvements accompanied the rapid inhibition of the classical pathway. There were 74 treatment-emergent adverse events in part A (n = 10) and 70 in part B (n = 6). Five serious adverse events were observed; 1 event (migraine) was assessed by the investigator as related to sutimlimab. These results demonstrated that in some patients with ITP, autoantibodies activate the classical complement pathway, accelerating platelet destruction or impairing platelet production and contributing to treatment failure. Thus, C1s inhibition may be a safe and beneficial therapeutic approach for patients with chronic/refractory ITP.


Asunto(s)
Púrpura Trombocitopénica Idiopática , Humanos , Adulto , Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Vía Clásica del Complemento , Recuento de Plaquetas , Anticuerpos Monoclonales Humanizados/uso terapéutico
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