Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 93
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Crit Care Med ; 52(8): e421-e430, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39007578

RESUMEN

RATIONALE: Critically ill adults can develop stress-related mucosal damage from gastrointestinal hypoperfusion and reperfusion injury, predisposing them to clinically important stress-related upper gastrointestinal bleeding (UGIB). OBJECTIVES: The objective of this guideline was to develop evidence-based recommendations for the prevention of UGIB in adults in the ICU. DESIGN: A multiprofessional panel of 18 international experts from dietetics, critical care medicine, nursing, and pharmacy, and two methodologists developed evidence-based recommendations in alignment with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Conflict-of-interest policies were strictly followed during all phases of guideline development including task force selection and voting. METHODS: The panel members identified and formulated 13 Population, Intervention, Comparison, and Outcome questions. We conducted a systematic review for each question to identify the best available evidence, statistically analyzed the evidence, and then assessed the certainty of the evidence using the GRADE approach. We used the evidence-to-decision framework to formulate the recommendations. Good practice statements were included to provide additional guidance. RESULTS: The panel generated nine conditional recommendations and made four good practice statements. Factors that likely increase the risk for clinically important stress-related UGIB in critically ill adults include coagulopathy, shock, and chronic liver disease. There is no firm evidence for mechanical ventilation alone being a risk factor. Enteral nutrition probably reduces UGIB risk. All critically ill adults with factors that likely increase the risk for stress-related UGIB should receive either proton pump inhibitors or histamine-2 receptor antagonists, at low dosage regimens, to prevent UGIB. Prophylaxis should be discontinued when critical illness is no longer evident or the risk factor(s) is no longer present despite ongoing critical illness. Discontinuation of stress ulcer prophylaxis before transfer out of the ICU is necessary to prevent inappropriate prescribing. CONCLUSIONS: The guideline panel achieved consensus regarding the recommendations for the prevention of stress-related UGIB. These recommendations are intended for consideration along with the patient's existing clinical status.


Asunto(s)
Cuidados Críticos , Enfermedad Crítica , Hemorragia Gastrointestinal , Humanos , Hemorragia Gastrointestinal/prevención & control , Adulto , Cuidados Críticos/métodos , Cuidados Críticos/normas , Inhibidores de la Bomba de Protones/uso terapéutico , Estrés Psicológico/complicaciones , Estrés Psicológico/prevención & control , Antagonistas de los Receptores H2 de la Histamina/uso terapéutico , Medicina Basada en la Evidencia
2.
Crit Care Med ; 52(2): 314-330, 2024 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-38240510

RESUMEN

RATIONALE: Clinical deterioration of patients hospitalized outside the ICU is a source of potentially reversible morbidity and mortality. To address this, some acute care hospitals have implemented systems aimed at detecting and responding to such patients. OBJECTIVES: To provide evidence-based recommendations for hospital clinicians and administrators to optimize recognition and response to clinical deterioration in non-ICU patients. PANEL DESIGN: The 25-member panel included representatives from medicine, nursing, respiratory therapy, pharmacy, patient/family partners, and clinician-methodologists with expertise in developing evidence-based Clinical Practice Guidelines. METHODS: We generated actionable questions using the Population, Intervention, Control, and Outcomes (PICO) format and performed a systematic review of the literature to identify and synthesize the best available evidence. We used the Grading of Recommendations Assessment, Development, and Evaluation Approach to determine certainty in the evidence and to formulate recommendations and good practice statements (GPSs). RESULTS: The panel issued 10 statements on recognizing and responding to non-ICU patients with critical illness. Healthcare personnel and institutions should ensure that all vital sign acquisition is timely and accurate (GPS). We make no recommendation on the use of continuous vital sign monitoring among unselected patients. We suggest focused education for bedside clinicians in signs of clinical deterioration, and we also suggest that patient/family/care partners' concerns be included in decisions to obtain additional opinions and help (both conditional recommendations). We recommend hospital-wide deployment of a rapid response team or medical emergency team (RRT/MET) with explicit activation criteria (strong recommendation). We make no recommendation about RRT/MET professional composition or inclusion of palliative care members on the responding team but suggest that the skill set of responders should include eliciting patients' goals of care (conditional recommendation). Finally, quality improvement processes should be part of a rapid response system. CONCLUSIONS: The panel provided guidance to inform clinicians and administrators on effective processes to improve the care of patients at-risk for developing critical illness outside the ICU.


Asunto(s)
Deterioro Clínico , Cuidados Críticos , Humanos , Cuidados Críticos/normas , Enfermedad Crítica/terapia , Práctica Clínica Basada en la Evidencia , Unidades de Cuidados Intensivos
3.
Crit Care Med ; 52(2): 307-313, 2024 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-38240509

RESUMEN

RATIONALE: Clinical deterioration of patients hospitalized outside the ICU is a source of potentially reversible morbidity and mortality. To address this, some acute care facilities have implemented systems aimed at detecting and responding to such patients. OBJECTIVES: To provide evidence-based recommendations for hospital clinicians and administrators to optimize recognition and response to clinical deterioration in non-ICU patients. PANEL DESIGN: The 25-member panel included representatives from medicine, nursing, respiratory therapy, pharmacy, patient/family partners, and clinician-methodologists with expertise in developing evidence-based clinical practice guidelines. METHODS: We generated actionable questions using the Population, Intervention, Control, and Outcomes format and performed a systematic review of the literature to identify and synthesize the best available evidence. We used the Grading of Recommendations Assessment, Development, and Evaluation approach to determine certainty in the evidence and to formulate recommendations and good practice statements (GPSs). RESULTS: The panel issued 10 statements on recognizing and responding to non-ICU patients with critical illness. Healthcare personnel and institutions should ensure that all vital sign acquisition is timely and accurate (GPS). We make no recommendation on the use of continuous vital sign monitoring among "unselected" patients due to the absence of data regarding the benefit and the potential harms of false positive alarms, the risk of alarm fatigue, and cost. We suggest focused education for bedside clinicians in signs of clinical deterioration, and we also suggest that patient/family/care partners' concerns be included in decisions to obtain additional opinions and help (both conditional recommendations). We recommend hospital-wide deployment of a rapid response team or medical emergency team (RRT/MET) with explicit activation criteria (strong recommendation). We make no recommendation about RRT/MET professional composition or inclusion of palliative care members on the responding team but suggest that the skill set of responders should include eliciting patients' goals of care (conditional recommendation). Finally, quality improvement processes should be part of a rapid response system (GPS). CONCLUSIONS: The panel provided guidance to inform clinicians and administrators on effective processes to improve the care of patients at-risk for developing critical illness outside the ICU.


Asunto(s)
Deterioro Clínico , Cuidados Críticos , Humanos , Cuidados Críticos/normas , Enfermedad Crítica/terapia , Unidades de Cuidados Intensivos , Mejoramiento de la Calidad
4.
Nucleic Acids Res ; 50(7): 4042-4053, 2022 04 22.
Artículo en Inglés | MEDLINE | ID: mdl-35380691

RESUMEN

Mtr4 is a eukaryotic RNA helicase required for RNA decay by the nuclear exosome. Previous studies have shown how RNA en route to the exosome threads through the highly conserved helicase core of Mtr4. Mtr4 also contains an arch domain, although details of potential interactions between the arch and RNA have been elusive. To understand the interaction of Saccharomyces cerevisiae Mtr4 with various RNAs, we have characterized RNA binding in solution using hydrogen-deuterium exchange mass spectrometry, and affinity and unwinding assays. We have identified RNA interactions within the helicase core that are consistent with existing structures and do not vary between tRNA, single-stranded RNA and double-stranded RNA constructs. We have also identified novel RNA interactions with a region of the arch known as the fist or KOW. These interactions are important for RNA unwinding and vary in strength depending on RNA structure and length. They account for Mtr4 discrimination between different RNAs. These interactions further drive Mtr4 to adopt a closed conformation characterized by reduced dynamics of the arch arm and intra-domain contacts between the fist and helicase core.


Asunto(s)
ARN Helicasas DEAD-box/química , Proteínas de Saccharomyces cerevisiae/química , ARN Helicasas DEAD-box/metabolismo , ADN Helicasas/metabolismo , Deuterio/metabolismo , Medición de Intercambio de Deuterio , Espectrometría de Masas , ARN/genética , ARN/metabolismo , ARN Helicasas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
5.
Biochemistry ; 60(38): 2888-2901, 2021 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-34496202

RESUMEN

Conformational dynamics are important factors in the function of enzymes, including protein tyrosine phosphatases (PTPs). Crystal structures of PTPs first revealed the motion of a protein loop bearing a conserved catalytic aspartic acid, and subsequent nuclear magnetic resonance and computational analyses have shown the presence of motions, involved in catalysis and allostery, within and beyond the active site. The tyrosine phosphatase from the thermophilic and acidophilic Sulfolobus solfataricus (SsoPTP) displays motions of its acid loop together with dynamics of its phosphoryl-binding P-loop and the Q-loop, the first instance of such motions in a PTP. All three loops share the same exchange rate, implying their motions are coupled. Further evidence of conformational flexibility comes from mutagenesis, kinetics, and isotope effect data showing that E40 can function as an alternate general acid to protonate the leaving group when the conserved acid, D69, is mutated to asparagine. SsoPTP is not the first PTP to exhibit an alternate general acid (after VHZ and TkPTP), but E40 does not correspond to the sequence or structural location of the alternate general acids in those precedents. A high-resolution X-ray structure with the transition state analogue vanadate clarifies the role of the active site arginine R102, which varied in structures of substrates bound to a catalytically inactive mutant. The coordinated motions of all three functional loops in SsoPTP, together with the function of an alternate general acid, suggest that catalytically competent conformations are present in solution that have not yet been observed in crystal structures.


Asunto(s)
Proteínas Tirosina Fosfatasas/genética , Sulfolobus solfataricus/enzimología , Secuencia de Aminoácidos/genética , Catálisis , Dominio Catalítico/genética , Cristalografía por Rayos X/métodos , Humanos , Cinética , Modelos Moleculares , Movimiento (Física) , Fosforilación/genética , Conformación Proteica , Proteínas Tirosina Fosfatasas/metabolismo , Proteínas Tirosina Fosfatasas/ultraestructura , Sulfolobus solfataricus/química , Sulfolobus solfataricus/metabolismo
6.
Biol Chem ; 402(5): 605-616, 2021 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-33857361

RESUMEN

Mtr4 is a Ski2-like RNA helicase that plays a central role in RNA surveillance and degradation pathways as an activator of the RNA exosome. Multiple crystallographic and cryo-EM studies over the past 10 years have revealed important insight into the Mtr4 structure and interactions with protein and nucleic acid binding partners. These structures place Mtr4 at the center of a dynamic process that recruits RNA substrates and presents them to the exosome. In this review, we summarize the available Mtr4 structures and highlight gaps in our current understanding.


Asunto(s)
ARN Helicasas , Humanos , Modelos Moleculares , Conformación Proteica , ARN Helicasas/química , ARN Helicasas/metabolismo
8.
RNA Biol ; 16(10): 1438-1447, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31232162

RESUMEN

Prokaryotic CRISPR-Cas adaptive immune systems rely on small non-coding RNAs derived from CRISPR loci to recognize and destroy complementary nucleic acids. However, the mechanism of Type IV CRISPR RNA (crRNA) biogenesis is poorly understood. To dissect the mechanism of Type IV CRISPR RNA biogenesis, we determined the x-ray crystal structure of the putative Type IV CRISPR associated endoribonuclease Cas6 from Mahella australiensis (Ma Cas6-IV) and characterized its enzymatic activity with RNA cleavage assays. We show that Ma Cas6-IV specifically cleaves Type IV crRNA repeats at the 3' side of a predicted stem loop, with a metal-independent, single-turnover mechanism that relies on a histidine and a tyrosine located within the putative endonuclease active site. Structure and sequence alignments with Cas6 orthologs reveal that although Ma Cas6-IV shares little sequence homology with other Cas6 proteins, all share common structural features that bind distinct crRNA repeat sequences. This analysis of Type IV crRNA biogenesis provides a structural and biochemical framework for understanding the similarities and differences of crRNA biogenesis across multi-subunit Class 1 CRISPR immune systems.


Asunto(s)
Proteínas Asociadas a CRISPR/metabolismo , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , ARN/química , ARN/genética , Transcripción Genética , Secuencia de Aminoácidos , Proteínas Asociadas a CRISPR/química , Catálisis , Dominio Catalítico , Firmicutes/genética , Firmicutes/metabolismo , Orden Génico , Modelos Moleculares , Conformación Molecular , Conformación de Ácido Nucleico , Precursores del ARN , Relación Estructura-Actividad , Especificidad por Sustrato
9.
J Am Pharm Assoc (2003) ; 59(6): 872-879, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31474527

RESUMEN

OBJECTIVES: The purpose of this study was to demonstrate the feasibility of implementing a Clinical Laboratory Improvement Amendments-waived real-time polymerase chain reaction (PCR) molecular test into a community pharmacy setting as part of a collaborative influenza and group A Streptococcus (GAS) disease management program. SETTING AND PARTICIPANTS: Two community pharmacy sites in Tennessee. PRACTICE DESCRIPTION: Patients presenting to the pharmacy with symptoms consistent with influenza or GAS from November 1, 2016, to April 30, 2018. PRACTICE INNOVATION: Influenza and GAS management programs based on previously developed protocols occurred at 2 community pharmacies in Tennessee. Pharmacies used the Cobas Liat testing system (Roche Diagnostics). Based on test results and under a collaborative practice agreement, pharmacists dispensed prescription medications for patients with a positive test: oseltamivir for influenza and amoxicillin for GAS. Patients with negative tests were treated with over-the-counter (OTC) medications or referred. Patients testing negative for GAS were asked to consent to having a second throat swab sent for culture. EVALUATION: Number of patients tested, point-of-care test results, and treatment received. RESULTS: Two hundred and two patients received care at the 2 pharmacies (116 for influenza, 46 for GAS, and 43 for both). Sixty (38%) tested positive for influenza, with 51 receiving an antiviral prescription, and 16 (18%) tested positive and were treated for GAS. No patient testing negative for either or positive for influenza was dispensed an antibiotic. For patients consenting to a follow-up culture, all GAS cultures sent for confirmatory testing were negative. CONCLUSION: A protocol-driven community pharmacy-based disease management program using real-time PCR testing for influenza and GAS was able to offer appropriate treatment to patients without overuse of antibiotics.


Asunto(s)
Servicios Comunitarios de Farmacia/organización & administración , Gripe Humana/diagnóstico , Pruebas en el Punto de Atención , Infecciones Estreptocócicas/diagnóstico , Adolescente , Adulto , Antibacterianos/administración & dosificación , Antivirales/administración & dosificación , Niño , Preescolar , Femenino , Humanos , Gripe Humana/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Farmacéuticos/organización & administración , Faringitis/diagnóstico , Faringitis/tratamiento farmacológico , Faringitis/microbiología , Reacción en Cadena de la Polimerasa , Infecciones Estreptocócicas/tratamiento farmacológico , Streptococcus pyogenes/aislamiento & purificación , Tennessee , Adulto Joven
10.
Am J Dermatopathol ; 40(2): e25-e27, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28700373

RESUMEN

Cutaneous complications secondary to transcatheter arterial chemoembolization (TACE) are exceptionally rare and may occur because of nontarget embolization of terminal vessels supplying the skin. We present a patient who developed painful retiform purpura on the right flank shortly after TACE for treatment of hepatocellular carcinoma. Biopsy revealed intravascular tan to yellow amorphous spherical structures within the dermis, confirming the presence of foreign material within these vessels. The authors review the literature and discuss previous cases of skin lesions manifesting after TACE, as well as potential factors influencing the probability of cutaneous complications. Histopathologic findings described in similar cases are presented. Prophylactic measures and attempted treatments to reduce likelihood of long-term injury are also reviewed. An awareness that cutaneous injury is a rare, but potential complication of transcatheter arterial embolization, as well as an understanding of management options is important for any provider using this procedure.


Asunto(s)
Erupciones por Medicamentos/etiología , Biopsia , Carcinoma Hepatocelular/terapia , Quimioembolización Terapéutica/efectos adversos , Humanos , Neoplasias Hepáticas/terapia , Masculino , Persona de Mediana Edad
11.
Crit Care Med ; 50(7): e662-e663, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35726997
12.
Crit Care Med ; 45(12): 2089-2098, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28938251

RESUMEN

OBJECTIVE: To provide a narrative review of the latest concepts and understanding of the pathophysiology of critical illness-related corticosteroid insufficiency (CIRCI). PARTICIPANTS: A multi-specialty task force of international experts in critical care medicine and endocrinology and members of the Society of Critical Care Medicine and the European Society of Intensive Care Medicine. DATA SOURCES: Medline, Database of Abstracts of Reviews of Effects (DARE), Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Database of Systematic Reviews. RESULTS: Three major pathophysiologic events were considered to constitute CIRCI: dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, altered cortisol metabolism, and tissue resistance to glucocorticoids. The dysregulation of the HPA axis is complex, involving multidirectional crosstalk between the CRH/ACTH pathways, autonomic nervous system, vasopressinergic system, and immune system. Recent studies have demonstrated that plasma clearance of cortisol is markedly reduced during critical illness, explained by suppressed expression and activity of the primary cortisol-metabolizing enzymes in the liver and kidney. Despite the elevated cortisol levels during critical illness, tissue resistance to glucocorticoids is believed to occur due to insufficient glucocorticoid alpha-mediated anti-inflammatory activity. CONCLUSIONS: Novel insights into the pathophysiology of CIRCI add to the limitations of the current diagnostic tools to identify at-risk patients and may also impact how corticosteroids are used in patients with CIRCI.


Asunto(s)
Insuficiencia Suprarrenal/fisiopatología , Enfermedad Crítica , Hidrocortisona/metabolismo , Sistema Hipotálamo-Hipofisario/fisiopatología , Sistema Hipófiso-Suprarrenal/fisiopatología , Comités Consultivos , Cuidados Críticos , Citocinas/metabolismo , Humanos , Células Neuroendocrinas/fisiología , Receptores de Glucocorticoides/fisiología , Índice de Severidad de la Enfermedad , Transducción de Señal , Síndrome de Respuesta Inflamatoria Sistémica/fisiopatología
13.
Crit Care Med ; 45(12): 2078-2088, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28938253

RESUMEN

OBJECTIVE: To update the 2008 consensus statements for the diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI) in adult and pediatric patients. PARTICIPANTS: A multispecialty task force of 16 international experts in critical care medicine, endocrinology, and guideline methods, all of them members of the Society of Critical Care Medicine and/or the European Society of Intensive Care Medicine. DESIGN/METHODS: The recommendations were based on the summarized evidence from the 2008 document in addition to more recent findings from an updated systematic review of relevant studies from 2008 to 2017 and were formulated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. The strength of each recommendation was classified as strong or conditional, and the quality of evidence was rated from high to very low based on factors including the individual study design, the risk of bias, the consistency of the results, and the directness and precision of the evidence. Recommendation approval required the agreement of at least 80% of the task force members. RESULTS: The task force was unable to reach agreement on a single test that can reliably diagnose CIRCI, although delta cortisol (change in baseline cortisol at 60 min of < 9 µg/dL) after cosyntropin (250 µg) administration and a random plasma cortisol of < 10 µg/dL may be used by clinicians. We suggest against using plasma-free cortisol or salivary cortisol level over plasma total cortisol (conditional, very low quality of evidence). For treatment of specific conditions, we suggest using IV hydrocortisone < 400 mg/day for ≥ 3 days at full dose in patients with septic shock that is not responsive to fluid and moderate- to high-dose vasopressor therapy (conditional, low quality of evidence). We suggest not using corticosteroids in adult patients with sepsis without shock (conditional recommendation, moderate quality of evidence). We suggest the use of IV methylprednisolone 1 mg/kg/day in patients with early moderate to severe acute respiratory distress syndrome (PaO2/FiO2 < 200 and within 14 days of onset) (conditional, moderate quality of evidence). Corticosteroids are not suggested for patients with major trauma (conditional, low quality of evidence). CONCLUSIONS: Evidence-based recommendations for the use of corticosteroids in critically ill patients with sepsis and septic shock, acute respiratory distress syndrome, and major trauma have been developed by a multispecialty task force.


Asunto(s)
Corticoesteroides/uso terapéutico , Insuficiencia Suprarrenal/diagnóstico , Insuficiencia Suprarrenal/tratamiento farmacológico , Cuidados Críticos/normas , Enfermedad Crítica/terapia , Comités Consultivos , Humanos , Hidrocortisona/sangre , Guías de Práctica Clínica como Asunto , Síndrome de Dificultad Respiratoria/tratamiento farmacológico , Sepsis/tratamiento farmacológico , Índice de Severidad de la Enfermedad , Choque Séptico/tratamiento farmacológico , Heridas y Lesiones/tratamiento farmacológico
15.
J Antimicrob Chemother ; 71(7): 1772-85, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-26968880

RESUMEN

OBJECTIVES: The optimum trough concentration of voriconazole for clinical response and safety is controversial. The objective of this review was to determine the optimum trough concentration of voriconazole and evaluate its relationship with efficacy and safety. METHODS: MEDLINE, EMBASE, ClinicalTrials.gov, the Cochrane Library and three Chinese literature databases were searched. Observational studies that compared clinical outcomes below and above the trough concentration cut-off value were included. We set the trough concentration cut-off value for efficacy as 0.5, 1.0, 1.5, 2.0 and 3.0 mg/L and for safety as 3.0, 4.0, 5.0, 5.5 and 6.0 mg/L. The efficacy outcomes were invasive fungal infection-related mortality, all-cause mortality, rate of successful treatment and rate of prophylaxis failure. The safety outcomes included incidents of hepatotoxicity, neurotoxicity and visual disorders. RESULTS: A total of 21 studies involving 1158 patients were included. Compared with voriconazole trough concentrations of >0.5 mg/L, levels of <0.5 mg/L significantly decreased the rate of treatment success (risk ratio = 0.46, 95% CI 0.29-0.74). The incidence of hepatotoxicity was significantly increased with trough concentrations >3.0, >4.0, >5.5 and >6.0 mg/L. The incidence of neurotoxicity was significantly increased with trough concentrations >4.0 and >5.5 mg/L. CONCLUSIONS: A voriconazole level of 0.5 mg/L should be considered the lower threshold associated with efficacy. A trough concentration >3.0 mg/L is associated with increased hepatotoxicity, particularly for the Asian population, and >4.0 mg/L is associated with increased neurotoxicity.


Asunto(s)
Antifúngicos/sangre , Antifúngicos/uso terapéutico , Infecciones Fúngicas Invasoras/tratamiento farmacológico , Micosis/tratamiento farmacológico , Voriconazol/sangre , Voriconazol/uso terapéutico , Antifúngicos/efectos adversos , Monitoreo de Drogas , Humanos , Infecciones Fúngicas Invasoras/prevención & control , Hígado/efectos de los fármacos , Micosis/prevención & control , Sistema Nervioso/efectos de los fármacos , Resultado del Tratamiento , Voriconazol/efectos adversos
16.
Ecol Appl ; 26(7): 2044-2059, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27755743

RESUMEN

Forest policymakers and managers have long sought ways to evaluate the capability of forest landscapes to jointly produce timber, habitat, and other ecosystem services in response to forest management. Currently, carbon is of particular interest as policies for increasing carbon storage on federal lands are being proposed. However, a challenge in joint production analysis of forest management is adequately representing ecological conditions and processes that influence joint production relationships. We used simulation models of vegetation structure, forest sector carbon, and potential wildlife habitat to characterize landscape-level joint production possibilities for carbon storage, timber harvest, and habitat for seven wildlife species across a range of forest management regimes. We sought to (1) characterize the general relationships of production possibilities for combinations of carbon storage, timber, and habitat, and (2) identify management variables that most influence joint production relationships. Our 160 000-ha study landscape featured environmental conditions typical of forests in the Western Cascade Mountains of Oregon (USA). Our results indicate that managing forests for carbon storage involves trade-offs among timber harvest and habitat for focal wildlife species, depending on the disturbance interval and utilization intensity followed. Joint production possibilities for wildlife species varied in shape, ranging from competitive to complementary to compound, reflecting niche breadth and habitat component needs of species examined. Managing Pacific Northwest forests to store forest sector carbon can be roughly complementary with habitat for Northern Spotted Owl, Olive-sided Flycatcher, and red tree vole. However, managing forests to increase carbon storage potentially can be competitive with timber production and habitat for Pacific marten, Pileated Woodpecker, and Western Bluebird, depending on the disturbance interval and harvest intensity chosen. Our analysis suggests that joint production possibilities under forest management regimes currently typical on industrial forest lands (e.g., 40- to 80-yr rotations with some tree retention for wildlife) represent but a small fraction of joint production outcomes possible in the region. Although the theoretical boundaries of the production possibilities sets we developed are probably unachievable in the current management environment, they arguably define the long-term potential of managing forests to produce multiple ecosystem services within and across multiple forest ownerships.


Asunto(s)
Carbono/fisiología , Agricultura Forestal , Bosques , Animales , Animales Salvajes , Carbono/química , Simulación por Computador , Conservación de los Recursos Naturales , Monitoreo del Ambiente , Modelos Biológicos , Oregon
17.
For Ecol Manage ; 366: 193-207, 2016 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-27041818

RESUMEN

Forest carbon (C) density varies tremendously across space due to the inherent heterogeneity of forest ecosystems. Variation of forest C density is especially pronounced in mountainous terrain, where environmental gradients are compressed and vary at multiple spatial scales. Additionally, the influence of environmental gradients may vary with forest age and developmental stage, an important consideration as forest landscapes often have a diversity of stand ages from past management and other disturbance agents. Quantifying forest C density and its underlying environmental determinants in mountain terrain has remained challenging because many available data sources lack the spatial grain and ecological resolution needed at both stand and landscape scales. The objective of this study was to determine if environmental factors influencing aboveground live carbon (ALC) density differed between young versus old forests. We integrated aerial light detection and ranging (lidar) data with 702 field plots to map forest ALC density at a grain of 25 m across the H.J. Andrews Experimental Forest, a 6369 ha watershed in the Cascade Mountains of Oregon, USA. We used linear regressions, random forest ensemble learning (RF) and sequential autoregressive modeling (SAR) to reveal how mapped forest ALC density was related to climate, topography, soils, and past disturbance history (timber harvesting and wildfires). ALC increased with stand age in young managed forests, with much greater variation of ALC in relation to years since wildfire in old unmanaged forests. Timber harvesting was the most important driver of ALC across the entire watershed, despite occurring on only 23% of the landscape. More variation in forest ALC density was explained in models of young managed forests than in models of old unmanaged forests. Besides stand age, ALC density in young managed forests was driven by factors influencing site productivity, whereas variation in ALC density in old unmanaged forests was also affected by finer scale topographic conditions associated with sheltered sites. Past wildfires only had a small influence on current ALC density, which may be a result of long times since fire and/or prevalence of non-stand replacing fire. Our results indicate that forest ALC density depends on a suite of multi-scale environmental drivers mediated by complex mountain topography, and that these relationships are dependent on stand age. The high and context-dependent spatial variability of forest ALC density has implications for quantifying forest carbon stores, establishing upper bounds of potential carbon sequestration, and scaling field data to landscape and regional scales.

18.
Crit Care Med ; 43(12): 2527-34, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26457751

RESUMEN

OBJECTIVE: The purpose of this study is to determine the rate of prolonged empiric antibiotic therapy in adult ICUs in the United States. Our secondary objective is to examine the relationship between the prolonged empiric antibiotic therapy rate and certain ICU characteristics. DESIGN: Multicenter, prospective, observational, 72-hour snapshot study. SETTING: Sixty-seven ICUs from 32 hospitals in the United States. PATIENTS: Nine hundred ninety-eight patients admitted to the ICU between midnight on June 20, 2011, and June 21, 2011, were included in the study. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Antibiotic orders were categorized as prophylactic, definitive, empiric, or prolonged empiric antibiotic therapy. Prolonged empiric antibiotic therapy was defined as empiric antibiotics that continued for at least 72 hours in the absence of adjudicated infection. Standard definitions from the Centers for Disease Control and Prevention were used to determine infection. Prolonged empiric antibiotic therapy rate was determined as the ratio of the total number of empiric antibiotics continued for at least 72 hours divided by the total number of empiric antibiotics. Univariate analysis of factors associated with the ICU prolonged empiric antibiotic therapy rate was conducted using Student t test. A total of 660 unique antibiotics were prescribed as empiric therapy to 364 patients. Of the empiric antibiotics, 333 of 660 (50%) were continued for at least 72 hours in instances where Centers for Disease Control and Prevention infection criteria were not met. Suspected pneumonia accounted for approximately 60% of empiric antibiotic use. The most frequently prescribed empiric antibiotics were vancomycin and piperacillin/tazobactam. ICUs that utilized invasive techniques for the diagnosis of ventilator-associated pneumonia had lower rates of prolonged empiric antibiotic therapy than those that did not, 45.1% versus 59.5% (p = 0.03). No other institutional factor was significantly associated with prolonged empiric antibiotic therapy rate. CONCLUSIONS: Half of all empiric antibiotics ordered in critically ill patients are continued for at least 72 hours in absence of adjudicated infection. Additional studies are needed to confirm these findings and determine the risks and benefits of prolonged empiric therapy in the critically ill.


Asunto(s)
Antibacterianos/uso terapéutico , Enfermedad Crítica , Utilización de Medicamentos/estadística & datos numéricos , Unidades de Cuidados Intensivos/estadística & datos numéricos , Pautas de la Práctica en Medicina/estadística & datos numéricos , Anciano , Antibacterianos/administración & dosificación , Profilaxis Antibiótica/estadística & datos numéricos , Esquema de Medicación , Femenino , Adhesión a Directriz/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Neumonía Asociada al Ventilador/tratamiento farmacológico , Guías de Práctica Clínica como Asunto , Estudios Prospectivos , Estados Unidos/epidemiología
19.
J Intensive Care Med ; 30(4): 217-25, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-24362446

RESUMEN

PURPOSE: Determine the level of evidence supporting off-label gastrointestinal (GI) medication use and identify the medication class and indication whereby off-label use was most common. MATERIALS AND METHODS: This prospective, multicentered observational study evaluated all medication orders written in 37 intensive care units (ICUs) in the United States, over a 24-hour period. All medications classified as "GI" according to a national reference were identified. The class and indication whereby off-label use was most prominent were determined and the level of evidence was described. RESULTS: There were 774 orders from 363 patients and 63% (489 of 774) were considered off-label. Proton pump inhibitors (PPIs) accounted for most of the off-label usage (55% [271 of 489]), followed by laxatives (16% [77 of 489]) and histamine-2-receptor antagonists (H2RAs; 15% [71 of 489]). When prescribed, 99% (271 of 274) of PPIs, 99% (71 of 72) of H2RAs, and 79% (30 of 38) of promotility agents were off-label. Stress ulcer prophylaxis (100% [309 of 309]), GI bleeding (100% [18 of 18]), and gastric motility (88% [30 of 34]) were the most common off-label indications. The most common strength of recommendation and level of evidence for off-label use was indeterminate (58% [282 of 489]) and none (57% [280 of 489]), respectively. CONCLUSION: The PPIs are the most widely used off-label medications in the ICU. Stress ulcer prophylaxis is the most common indication. The level of evidence supporting off-label GI medication use is poor.


Asunto(s)
Fármacos Gastrointestinales/uso terapéutico , Unidades de Cuidados Intensivos/estadística & datos numéricos , Uso Fuera de lo Indicado/estadística & datos numéricos , Adulto , Hemorragia Gastrointestinal/tratamiento farmacológico , Motilidad Gastrointestinal , Antagonistas de los Receptores H2 de la Histamina/uso terapéutico , Humanos , Laxativos/uso terapéutico , Úlcera Péptica/prevención & control , Estudios Prospectivos , Inhibidores de la Bomba de Protones/uso terapéutico , Estrés Fisiológico
20.
Am J Respir Cell Mol Biol ; 50(4): 737-47, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24175906

RESUMEN

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive fibrotic destruction of normal lung architecture. Due to a lack of effective treatment options, new treatment approaches are needed. We previously identified transglutaminase (TG)2, a multifunctional protein expressed by human lung fibroblasts (HLFs), as a positive driver of fibrosis. TG2 catalyzes crosslinking of extracellular matrix proteins, enhances cell binding to fibronectin and integrin, and promotes fibronectin expression. We investigated whether the small electrophilic molecules 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) and 15-deoxy-delta-12,14-prostaglandin J2 (15d-PGJ2) inhibit the expression and profibrotic functions of TG2. CDDO and 15d-PGJ2 reduced expression of TG2 mRNA and protein in primary HLFs from control donors and donors with IPF. CDDO and 15d-PGJ2 also decreased the in vitro profibrotic effector functions of HLFs including collagen gel contraction and cell migration. The decrease in TG2 expression did not occur through activation of the peroxisome proliferator activated receptor γ or generation of reactive oxidative species. CDDO and 15d-PGJ2 inhibited the extracellular signal-regulated kinase pathway, resulting in the suppression of TG2 expression. This is the first study to show that small electrophilic compounds inhibit the expression and profibrotic effector functions of TG2, a key promoter of fibrosis. These studies identify new and important antifibrotic activities of these two small molecules, which could lead to new treatments for fibrotic lung disease.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Fibrosis Pulmonar Idiopática/enzimología , Pulmón/efectos de los fármacos , Ácido Oleanólico/análogos & derivados , Prostaglandina D2/análogos & derivados , Transglutaminasas/antagonistas & inhibidores , Estudios de Casos y Controles , Movimiento Celular/efectos de los fármacos , Forma de la Célula/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Inhibidores Enzimáticos/química , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Fibroblastos/efectos de los fármacos , Fibroblastos/enzimología , Fibroblastos/patología , Proteínas de Unión al GTP , Humanos , Fibrosis Pulmonar Idiopática/patología , Pulmón/enzimología , Pulmón/patología , Quinasas Quinasa Quinasa PAM/antagonistas & inhibidores , Quinasas Quinasa Quinasa PAM/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Terapia Molecular Dirigida , Ácido Oleanólico/química , Ácido Oleanólico/farmacología , Fosforilación , Prostaglandina D2/química , Prostaglandina D2/farmacología , Proteína Glutamina Gamma Glutamiltransferasa 2 , Inhibidores de Proteínas Quinasas/farmacología , Transglutaminasas/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA