Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 117
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
BMC Neurol ; 24(1): 12, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38166710

RESUMEN

BACKGROUND: The purpose of this study was to examine the impact of ARC on levetiracetam concentrations during the first week following acute TBI. The hypothesis was levetiracetam concentrations are significantly lower in TBI patients with augmented renal clearance (ARC) compared to those with normal renal clearance. METHODS: This is a prospective cohort pharmacokinetic study of adults with moderate to severe TBI treated with levetiracetam during the first week after injury. Serial blood collections were performed daily for analysis of levetiracetam, cystatin C, and 12-hr creatinine clearance (CrCl) determinations. Patients were divided into two cohorts: with (CrCl ≥130 ml/min/1.73 m2) and without ARC. RESULTS: Twenty-two patients with moderate to severe TBI were included. The population consisted primarily of young male patients with severe TBI (mean age 40 years old, 68% male, median admission GCS 4). Each received levetiracetam 1000 mg IV every 12 h for the study period. ARC was present in 77.3% of patients, with significantly lower levetiracetam concentrations in ARC patients and below the conservative therapeutic range (< 6mcg/mL) for all study days. In patients without ARC, the serum concentrations were also below the expected range on all but two study days (Days 4 and 5). Four of the 22 (18.2%) patients exhibited seizure activity during the study period (two of these patients exhibited ARC). Cystatin C concentrations were significantly lower in patients with ARC, though the mean for all patients was within the typical normal range. CONCLUSIONS: ARC has a high prevalence in patients with moderate to severe TBI. Levetiracetam concentrations after standard dosing were low in all TBI patients, but significantly lower in patients with ARC. This study highlights the need to consider personalized drug dosing in TBI patients irrespective of the presence of ARC. CLINICAL TRIAL REGISTRATION: This study was registered at cliicaltrials.gov (NCT02437838) Registered on 08/05/2015, https://clinicaltrials.gov/ct2/show/NCT02437838 .


Asunto(s)
Lesiones Traumáticas del Encéfalo , Cistatina C , Adulto , Humanos , Masculino , Femenino , Levetiracetam/uso terapéutico , Estudios Prospectivos , Lesiones Traumáticas del Encéfalo/complicaciones , Lesiones Traumáticas del Encéfalo/tratamiento farmacológico
2.
Neurocrit Care ; 40(1): 262-271, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37322326

RESUMEN

BACKGROUND: Dual antiplatelet therapy (DAPT) is commonly employed for neuroendovascular stenting due to the significant risk of thromboembolism. Clopidogrel and aspirin are most often selected as initial DAPTs; however, there is limited literature available to support guidance of DAPT in this setting. The objective of this study was to evaluate safety and efficacy in patients whose final regimen included either DAPT with aspirin and clopidogrel (DAPT-C) or DAPT with aspirin and ticagrelor (DAPT-T). METHODS: This was a multicenter, retrospective cohort of patients who underwent neuroendovascular stenting and received DAPT between July 1, 2017, and October 31, 2020. Study participants were allocated into groups based on discharge DAPT regimen. The primary outcome was incidence of stent thrombosis at 3-6 months on DAPT-C versus DAPT-T, as defined by the presence of thrombus on imaging or new onset stroke. Secondary outcomes included major and minor bleeding and death within 3-6 months after the procedure. RESULTS: Five hundred and seventy patients were screened across 12 sites. Of those, 486 were included (DAPT-C n = 360, DAPT-T n = 126). There was no difference in the primary outcome of stent thrombosis between the DAPT-C and DAPT-T groups (8% vs. 8%, p = 0.97) and no difference in any of the secondary safety outcomes. CONCLUSIONS: Using DAPT-C or DAPT-T regimens in a broad population of neuroendovascular stenting procedures appears to have similar safety and efficacy profiles. Further prospective evaluation is warranted to streamline the practice of DAPT selection and monitoring to determine the impact on clinical outcomes.


Asunto(s)
Inhibidores de Agregación Plaquetaria , Trombosis , Humanos , Clopidogrel/uso terapéutico , Ticagrelor/uso terapéutico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Estudios Retrospectivos , Aspirina/uso terapéutico , Stents/efectos adversos , Trombosis/tratamiento farmacológico , Resultado del Tratamiento
3.
Circulation ; 141(21): 1681-1689, 2020 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-32264698

RESUMEN

BACKGROUND: Since the approval of the oral factor Xa inhibitors, there have been concerns regarding the ability to neutralize their anticoagulant effects after intracranial hemorrhage (ICH). Multiple guidelines suggest using prothrombin complex concentrates (PCCs) in these patients on the basis of research that includes a limited number of patients with ICH. Given this, we aimed to evaluate the safety and efficacy of PCCs for factor Xa inhibitor-related ICH in a large, multicenter cohort of patients. METHODS: This was a multicenter, retrospective, observational cohort study of patients with apixaban- or rivaroxaban-related ICH who received PCCs between January 1, 2015, and March 1, 2019. The study had 2 primary analysis groups: safety and hemostatic efficacy. The safety analysis evaluated all patients meeting inclusion criteria for the occurrence of a thrombotic event, which were censored at hospital discharge or 30 days after PCC administration. Patients with intracerebral, subarachnoid, or subdural hemorrhages who had at least 1 follow-up image within 24 hours of PCC administration were assessed for hemostatic efficacy. The primary efficacy outcome was the percentage of patients with excellent or good hemostasis on the basis of the modified Sarode criteria. Secondary outcomes included an evaluation of in-hospital mortality, length of stay, infusion-related reactions, and thrombotic event occurrence during multiple predefined periods. RESULTS: A total of 663 patients were included and assessed for safety outcomes. Of these, 433 patients met criteria for hemostatic efficacy evaluation. We observed excellent or good hemostasis in 354 patients (81.8% [95% CI, 77.9-85.2]). Twenty-five (3.8%) patients had a total of 26 thrombotic events, of which 22 occurred in the first 14 days after PCC administration. One patient had documentation of an infusion-related reaction. For the full cohort of patients, in-hospital mortality was 19.0%, and the median intensive care unit and hospital lengths of stay were 2.0 and 6.0 days, respectively. CONCLUSIONS: Administration of PCCs after apixaban- and rivaroxaban-related ICH provided a high rate of excellent or good hemostasis (81.8%) coupled with a 3.8% thrombosis rate. Randomized, controlled trials evaluating the clinical efficacy of PCCs in patients with factor Xa inhibitor-related ICH are needed.


Asunto(s)
Factores de Coagulación Sanguínea/uso terapéutico , Inhibidores del Factor Xa/efectos adversos , Hematoma Subdural/tratamiento farmacológico , Hemostasis/efectos de los fármacos , Hemostáticos/uso terapéutico , Pirazoles/efectos adversos , Piridonas/efectos adversos , Rivaroxabán/efectos adversos , Hemorragia Subaracnoidea/tratamiento farmacológico , Anciano , Factores de Coagulación Sanguínea/efectos adversos , Femenino , Hematoma Subdural/inducido químicamente , Hematoma Subdural/diagnóstico por imagen , Hematoma Subdural/mortalidad , Hemostáticos/efectos adversos , Mortalidad Hospitalaria , Humanos , Trombosis Intracraneal/inducido químicamente , Tiempo de Internación , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Hemorragia Subaracnoidea/inducido químicamente , Hemorragia Subaracnoidea/diagnóstico por imagen , Hemorragia Subaracnoidea/mortalidad , Factores de Tiempo , Resultado del Tratamiento , Estados Unidos
4.
J Neurophysiol ; 126(6): 1903-1924, 2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34669505

RESUMEN

Studies elucidating modulation of microcircuit activity in isolated nervous systems have revealed numerous insights regarding neural circuit flexibility, but this approach limits the link between experimental results and behavioral context. To bridge this gap, we studied feeding behavior-linked modulation of microcircuit activity in the isolated stomatogastric nervous system (STNS) of male Cancer borealis crabs. Specifically, we removed hemolymph from a crab that was unfed for ≥24 h ("unfed" hemolymph) or fed 15 min to 2 h before hemolymph removal ("fed" hemolymph). After feeding, the first significant foregut emptying occurred >1 h later and complete emptying required ≥6 h. We applied the unfed or fed hemolymph to the stomatogastric ganglion (STG) in an isolated STNS preparation from a separate, unfed crab to determine its influence on the VCN (ventral cardiac neuron)-triggered gastric mill (chewing) and pyloric (filtering of chewed food) rhythms. Unfed hemolymph had little influence on these rhythms, but fed hemolymph from each examined time-point (15 min, 1 h, or 2 h after feeding) slowed one or both rhythms without weakening circuit neuron activity. There were also distinct parameter changes associated with each time-point. One change unique to the 1-h time-point (i.e., reduced activity of one circuit neuron during the transition from the gastric mill retraction to protraction phase) suggested that the fed hemolymph also enhanced the influence of a projection neuron that innervates the STG from a ganglion isolated from the applied hemolymph. Hemolymph thus provides a feeding state-dependent modulation of the two feeding-related motor patterns in the C. borealis STG.NEW & NOTEWORTHY Little is known about behavior-linked modulation of microcircuit activity. We show that the VCN-triggered gastric mill (chewing) and pyloric (food filtering) rhythms in the isolated crab Cancer borealis stomatogastric nervous system were changed by applying hemolymph from recently fed but not unfed crabs. This included some distinct parameter changes during each examined post-fed hemolymph time-point. These results suggest the presence of feeding-related changes in circulating hormones that regulate consummatory microcircuit activity.


Asunto(s)
Generadores de Patrones Centrales/fisiología , Fenómenos Fisiológicos del Sistema Digestivo , Molleja No Aviar/fisiología , Hemolinfa/fisiología , Periodicidad , Animales , Conducta Animal , Braquiuros , Conducta Alimentaria , Ganglios de Invertebrados , Masculino
5.
Am J Emerg Med ; 47: 90-94, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33794475

RESUMEN

BACKGROUND & PURPOSE: Alteplase is the standard of care for early pharmacologic thrombolysis after acute ischemic stroke (AIS). Alteplase is also considered a high-alert medication and is fraught with potential for error. We sought to describe the difference in medication error rates in in patients receiving alteplase for acute ischemic stroke from regional hospitals compared to patients receiving alteplase at the Comprehensive Stroke Center. METHODS: This was a retrospective cohort comparison of patients who were greater than 18 years old that received intravenous alteplase for the treatment of AIS from June 2015 to June 2018. Several institution specific databases were utilized to obtain pertinent data. A standardized taxonomy was utilized to classify medication errors. Patients were excluded if they received any fibrinolytic other than alteplase or if alteplase was used for a non-stroke indication. Two cohorts (from regional hospitals or the Comprehensive Stroke Center (CSC)) were compared. RESULTS: A total of 676 patients received alteplase during the study period (34% from the CSC and 66% from regional hospitals). There were 133 (19.8%) errors identified. Ten errors (1.6%) occurred at the CSC and 123 (18.2%) errors occurred at regional hospitals. More patients who had an error with alteplase administration (12.7%) experienced a hemorrhagic conversion compared to those with no error in administration (7.2%, p= 0.04). CONCLUSION: The error rate of alteplase infusion for ischemic stroke is high, particularly in patients from referring centers. Errors may be associated with adverse events. Further education and administration safeguards should be implemented to decrease the risk of medication errors.


Asunto(s)
Fibrinolíticos/administración & dosificación , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Errores de Medicación/estadística & datos numéricos , Activador de Tejido Plasminógeno/administración & dosificación , Administración Intravenosa , Adulto , Anciano , Anciano de 80 o más Años , Bases de Datos Factuales , Femenino , Fibrinolíticos/efectos adversos , Hospitales Especializados/estadística & datos numéricos , Humanos , Accidente Cerebrovascular Isquémico/epidemiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Terapia Trombolítica/métodos , Activador de Tejido Plasminógeno/efectos adversos
6.
Neurocrit Care ; 34(2): 593-607, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32794143

RESUMEN

Alcohol withdrawal syndrome (AWS) can range from mild jittery movements, nausea, sweating to more severe symptoms such as seizure and death. Severe AWS can worsen cognitive function, increase hospital length of stay, and in-hospital mortality and morbidity. Due to a lack of reliable history of present illness in many patients with neurological injury as well as similarities in clinical presentation of AWS and some commonly encountered neurological syndromes, the true incidence of AWS in neurocritical care patients remains unknown. This review discusses challenges in the assessment and treatment of AWS in patients with neurological injury, including the utility of different scoring systems such as the Clinical Institute Withdrawal Assessment and the Minnesota Detoxification Scale as well as the reliability of admission alcohol levels in predicting AWS. Treatment strategies such as symptom-based versus fixed dose benzodiazepine therapy and alternative agents such as baclofen, carbamazepine, dexmedetomidine, gabapentin, phenobarbital, ketamine, propofol, and valproic acid are also discussed. Finally, a treatment algorithm considering the neurocritical care patient is proposed to help guide therapy in this setting.


Asunto(s)
Alcoholismo , Síndrome de Abstinencia a Sustancias , Benzodiazepinas , Humanos , Hipnóticos y Sedantes/uso terapéutico , Reproducibilidad de los Resultados , Estudios Retrospectivos , Síndrome de Abstinencia a Sustancias/tratamiento farmacológico , Síndrome de Abstinencia a Sustancias/terapia
7.
Neurocrit Care ; 35(1): 130-138, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33219462

RESUMEN

BACKGROUND/OBJECTIVE: Inactivated four-factor prothrombin complex concentrate (I4F-PCC, Kcentra®) has become an important agent for the urgent or emergent reversal of bleeding associated with vitamin K antagonists such as warfarin. There is recognized inter-institutional variability with the use of I4F-PCC, especially as it relates to dosing practices. We sought to characterize variations in I4F-PCC dosing practices and their impact on patient outcomes and describe overall real-world clinical practice surrounding I4F-PCC utilization in the context of the management of warfarin-related intracranial hemorrhage (ICH). METHODS: This is a multicenter retrospective pragmatic registry study of adult patients admitted at a participating study site between January 1, 2014, and December 31, 2015, who received I4F-PCC for reversal of warfarin-related ICH. Practices around warfarin-related ICH reversal in context of I4F-PCC utilization are described, including repeat I4F-PCC dosing, adjunctive reversal agents, and dose rounding policies (i.e., rounding doses to nearest vial size vs preparing exact/unrounded doses). All research was approved by local human investigation committees at each institution. RESULTS: Seventeen institutions contributed data on 528 patients to this registry. These institutions were primarily urban centers (74%), located in the southeast USA (47%), with Level 1 Trauma designation (79%), and with Comprehensive Stroke Center designation (74%). Most patients included in the study had sustained a non-traumatic ICH (68%), had a median admission GCS of 14 (IQR 7-15), and were receiving warfarin for atrial fibrillation (57.4%). There was substantial time latency between baseline INR and I4F-PCC (median 2.4 h, IQR 1.4-4.5 h). Most patients received adjunctive reversal agents, including vitamin K (89.5%) and fresh frozen plasma (FFP) (31.9%). A smaller proportion (6.0%) of patients received repeat I4F-PCC dosing. The median ICU length of stay (LOS) was 3 days (IQR 2-7 days), median hospital LOS was 6 days (IQR 3-12 days), and overall mortality rate was 28.8%. For institutions rounding doses to the nearest vial size, the first post-I4F-PCC dose INR was statistically but not clinically significantly lower than for institutions without vial size dose rounding, with comparable degrees of INR reduction from baseline. No differences were observed between dose rounding cohorts in adverse effects, ICU or hospital LOS, modified Rankin score at discharge, or mortality rates. CONCLUSIONS: Most patients received single doses of I4F-PCC, with adjunctive reversal agents and rounding doses to vial size. The time difference from baseline INR to factor product administration is a potential opportunity for process improvement in the management of warfarin-related ICH.


Asunto(s)
Anticoagulantes , Warfarina , Adulto , Anticoagulantes/efectos adversos , Factores de Coagulación Sanguínea , Humanos , Relación Normalizada Internacional , Hemorragias Intracraneales/inducido químicamente , Hemorragias Intracraneales/tratamiento farmacológico , Estudios Retrospectivos , Warfarina/efectos adversos
8.
Neurocrit Care ; 35(1): 39-45, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33150575

RESUMEN

BACKGROUND/OBJECTIVE: Stress-related mucosal bleeding (SRMB) occurs in approximately 2-4% of critically ill patients. Patients with aneurysmal subarachnoid hemorrhage (aSAH) have a (diffuse) space-occupying lesion, are critically ill, often require mechanical ventilation, and frequently receive anticoagulation or antiplatelet therapy after aneurysm embolization, all of which may be risk factors for SRMB. However, no studies have evaluated SRMB in patients with aSAH. Aims of the study were to determine the incidence of SRMB in aSAH patients, evaluate the effect of acid suppression on SRMB, and identify specific risk factors for SRMB. METHODS: This was a multicenter, retrospective, observational study conducted across 17 centers. Each center reviewed up to 50 of the most recent cases of aSAH. Patients with length of stay (LOS) < 48 h or active GI bleeding on admission were excluded. Variables related to demographics, aSAH severity, gastrointestinal (GI) bleeding, provision of SRMB prophylaxis, adverse events, intensive care unit (ICU), and hospital LOS were collected for the first 21 days of admission or until hospital discharge, whichever came first. Descriptive statistics were used to analyze the data. A multivariate logistic regression modeling was utilized to examine the relationship between specific risk factors and the incidence of clinically important GI bleeding in patients with aSAH. RESULTS: A total of 627 patients were included. The overall incidence of clinically important GI bleeding was 4.9%. Of the patients with clinically important GI bleeding, 19 (61%) received pharmacologic prophylaxis prior to evidence of GI bleeding, while 12 (39%) were not on pharmacologic prophylaxis at the onset of GI bleeding. Patients who received an acid suppressant agent were less likely to experience GI bleeding than patients who did not receive pharmacologic prophylaxis prior to evidence of bleeding (OR 0.39, 95% CI 0.18-0.83). The multivariate regression analysis identified any instance of elevated intracranial pressure, creatinine clearance < 60 ml/min and the incidence of cerebral vasospasm as specific risk factors associated with GI bleeding. Cerebral vasospasm has not previously been described as a risk for GI bleeding (OR 2.5 95% CI 1.09-5.79). CONCLUSIONS: Clinically important GI bleeding occurred in 4.9% of patients with aSAH, similar to the general critical care population. Risk factors associated with GI bleeding were prolonged mechanical ventilation (> 48 h), creatinine clearance < 60 ml/min, presence of coagulopathy, elevation of intracranial pressure, and cerebral vasospasm. Further prospective research is needed to confirm this observation within this patient population.


Asunto(s)
Embolización Terapéutica , Hemorragia Subaracnoidea , Vasoespasmo Intracraneal , Hemorragia Gastrointestinal/epidemiología , Hemorragia Gastrointestinal/etiología , Hemorragia Gastrointestinal/terapia , Humanos , Estudios Retrospectivos , Factores de Riesgo , Hemorragia Subaracnoidea/complicaciones , Hemorragia Subaracnoidea/epidemiología , Hemorragia Subaracnoidea/terapia
9.
J Exp Biol ; 223(Pt 20)2020 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-32820029

RESUMEN

Neuronal inputs to microcircuits are often present as multiple copies of apparently equivalent neurons. Thus far, however, little is known regarding the relative influence on microcircuit output of activating all or only some copies of such an input. We examine this issue in the crab (Cancer borealis) stomatogastric ganglion, where the gastric mill (chewing) microcircuit is activated by modulatory commissural neuron 1 (MCN1), a bilaterally paired modulatory projection neuron. Both MCN1s contain the same co-transmitters, influence the same gastric mill microcircuit neurons, can drive the biphasic gastric mill rhythm, and are co-activated by all identified MCN1-activating pathways. Here, we determine whether the gastric mill microcircuit response is equivalent when stimulating one or both MCN1s under conditions where the pair are matched to collectively fire at the same overall rate and pattern as single MCN1 stimulation. The dual MCN1 stimulations elicited more consistently coordinated rhythms, and these rhythms exhibited longer phases and cycle periods. These different outcomes from single and dual MCN1 stimulation may have resulted from the relatively modest, and equivalent, firing rate of the gastric mill neuron LG (lateral gastric) during each matched set of stimulations. The LG neuron-mediated, ionotropic inhibition of the MCN1 axon terminals is the trigger for the transition from the retraction to protraction phase. This LG neuron influence on MCN1 was more effective during the dual stimulations, where each MCN1 firing rate was half that occurring during the matched single stimulations. Thus, equivalent individual- and co-activation of a class of modulatory projection neurons does not necessarily drive equivalent microcircuit output.


Asunto(s)
Braquiuros , Ganglios de Invertebrados , Potenciales de Acción , Animales , Interneuronas , Red Nerviosa , Neuronas , Periodicidad
10.
Neurocrit Care ; 32(3): 647-666, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32227294

RESUMEN

BACKGROUND: Acute treatment of cerebral edema and elevated intracranial pressure is a common issue in patients with neurological injury. Practical recommendations regarding selection and monitoring of therapies for initial management of cerebral edema for optimal efficacy and safety are generally lacking. This guideline evaluates the role of hyperosmolar agents (mannitol, HTS), corticosteroids, and selected non-pharmacologic therapies in the acute treatment of cerebral edema. Clinicians must be able to select appropriate therapies for initial cerebral edema management based on available evidence while balancing efficacy and safety. METHODS: The Neurocritical Care Society recruited experts in neurocritical care, nursing, and pharmacy to create a panel in 2017. The group generated 16 clinical questions related to initial management of cerebral edema in various neurological insults using the PICO format. A research librarian executed a comprehensive literature search through July 2018. The panel screened the identified articles for inclusion related to each specific PICO question and abstracted necessary information for pertinent publications. The panel used GRADE methodology to categorize the quality of evidence as high, moderate, low, or very low based on their confidence that the findings of each publication approximate the true effect of the therapy. RESULTS: The panel generated recommendations regarding initial management of cerebral edema in neurocritical care patients with subarachnoid hemorrhage, traumatic brain injury, acute ischemic stroke, intracerebral hemorrhage, bacterial meningitis, and hepatic encephalopathy. CONCLUSION: The available evidence suggests hyperosmolar therapy may be helpful in reducing ICP elevations or cerebral edema in patients with SAH, TBI, AIS, ICH, and HE, although neurological outcomes do not appear to be affected. Corticosteroids appear to be helpful in reducing cerebral edema in patients with bacterial meningitis, but not ICH. Differences in therapeutic response and safety may exist between HTS and mannitol. The use of these agents in these critical clinical situations merits close monitoring for adverse effects. There is a dire need for high-quality research to better inform clinicians of the best options for individualized care of patients with cerebral edema.


Asunto(s)
Edema Encefálico/terapia , Diuréticos Osmóticos/uso terapéutico , Glucocorticoides/uso terapéutico , Hipertensión Intracraneal/terapia , Manitol/uso terapéutico , Solución Salina Hipertónica/uso terapéutico , Edema Encefálico/etiología , Lesiones Traumáticas del Encéfalo/complicaciones , Hemorragia Cerebral/complicaciones , Derivaciones del Líquido Cefalorraquídeo/métodos , Cuidados Críticos , Servicios Médicos de Urgencia , Encefalopatía Hepática/complicaciones , Humanos , Hipertensión Intracraneal/etiología , Accidente Cerebrovascular Isquémico/complicaciones , Meningitis Bacterianas/complicaciones , Posicionamiento del Paciente/métodos , Sociedades Médicas , Hemorragia Subaracnoidea/complicaciones
11.
J Biol Chem ; 293(22): 8521-8529, 2018 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-29622678

RESUMEN

Platelets are recruited to sites of vascular injury, where they are activated and aggregate to form a hemostatic plug. This process requires the activation of the small GTPase Rap1B by its cognate guanine nucleotide exchange factor CalDAG-GEFI. Studies on platelet function suggest that CalDAG-GEFI activity is regulated by changes in cytosolic calcium, but the exact molecular mechanism is poorly understood. Here we show that purified CalDAG-GEFI is autoinhibited and directly regulated by calcium. Substitutions of putative calcium-binding residues within the canonical EF hands of CalDAG-GEFI diminish its capacity to activate Rap1B. Structural differences between active (WT) and inactive (EF hand variant) CalDAG-GEFI protein were determined by hydrogen-deuterium exchange MS. The highest differential rates of deuterium uptake in WT over EF hand variant CalDAG-GEFI were observed in regions within the catalytic Cdc25 domain and a putative autoinhibitory linker connecting the Cdc25 and EF hand domains. Exchange activity in the EF hand variant was fully restored by an additional substitution, valine 406 to glutamate, which is thought to disrupt the interface between the autoinhibitory linker and the Cdc25 domain. Overall, our results suggest a model for how CalDAG-GEFI remains in an autoinhibited state when levels of cytosolic calcium in resting platelets are low. In response to cellular stimulation, calcium mobilization and binding to the EF hands causes conformational rearrangements within CalDAG-GEFI, including the autoinhibitory linker that frees the catalytic surface of CalDAG-GEFI to engage and activate Rap1B. The data from this study are the first evidence linking CalDAG-GEFI activity directly to calcium.


Asunto(s)
Plaquetas/efectos de los fármacos , Calcio/farmacología , Motivos EF Hand , Factores de Intercambio de Guanina Nucleótido/antagonistas & inhibidores , Agregación Plaquetaria , Conformación Proteica/efectos de los fármacos , Proteínas de Unión al GTP rap/metabolismo , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/metabolismo , Humanos , Modelos Moleculares , Transducción de Señal , Proteínas de Unión al GTP rap/genética
12.
J Neurophysiol ; 121(3): 950-972, 2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-30649961

RESUMEN

Microcircuit modulation by peptides is well established, but the cellular/synaptic mechanisms whereby identified neurons with identified peptide transmitters modulate microcircuits remain unknown for most systems. Here, we describe the distribution of GYRKPPFNGSIFamide (Gly1-SIFamide) immunoreactivity (Gly1-SIFamide-IR) in the stomatogastric nervous system (STNS) of the crab Cancer borealis and the Gly1-SIFamide actions on the two feeding-related circuits in the stomatogastric ganglion (STG). Gly1-SIFamide-IR localized to somata in the paired commissural ganglia (CoGs), two axons in the nerves connecting each CoG with the STG, and the CoG and STG neuropil. We identified one Gly1-SIFamide-IR projection neuron innervating the STG as the previously identified modulatory commissural neuron 5 (MCN5). Brief (~10 s) MCN5 stimulation excites some pyloric circuit neurons. We now find that bath applying Gly1-SIFamide to the isolated STG also enhanced pyloric rhythm activity and activated an imperfectly coordinated gastric mill rhythm that included unusually prolonged bursts in two circuit neurons [inferior cardiac (IC), lateral posterior gastric (LPG)]. Furthermore, longer duration (>30 s) MCN5 stimulation activated a Gly1-SIFamide-like gastric mill rhythm, including prolonged IC and LPG bursting. The prolonged LPG bursting decreased the coincidence of its activity with neurons to which it is electrically coupled. We also identified local circuit feedback onto the MCN5 axon terminals, which may contribute to some distinctions between the responses to MCN5 stimulation and Gly1-SIFamide application. Thus, MCN5 adds to the few identified projection neurons that modulate a well-defined circuit at least partly via an identified neuropeptide transmitter and provides an opportunity to study peptide regulation of electrical coupled neurons in a functional context. NEW & NOTEWORTHY Limited insight exists regarding how identified peptidergic neurons modulate microcircuits. We show that the modulatory projection neuron modulatory commissural neuron 5 (MCN5) is peptidergic, containing Gly1-SIFamide. MCN5 and Gly1-SIFamide elicit similar output from two well-defined motor circuits. Their distinct actions may result partly from circuit feedback onto the MCN5 axon terminals. Their similar actions include eliciting divergent activity patterns in normally coactive, electrically coupled neurons, providing an opportunity to examine peptide modulation of electrically coupled neurons in a functional context.


Asunto(s)
Axones/fisiología , Ganglios de Invertebrados/fisiología , Contracción Muscular , Neuropéptidos/farmacología , Píloro/inervación , Potenciales de Acción , Animales , Axones/efectos de los fármacos , Braquiuros , Retroalimentación Fisiológica , Ganglios de Invertebrados/citología , Ganglios de Invertebrados/efectos de los fármacos , Periodicidad , Píloro/fisiología
14.
Neurocrit Care ; 30(3): 609-616, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30446934

RESUMEN

BACKGROUND: Central nervous system (CNS) infections are particularly prevalent in the adult neurocritical care patient population and are associated with significant morbidity and mortality. Factors relevant to the nature of CNS infections pose significant challenges to clinicians treating afflicted patients. Intraventricular (IVT) administration of antibiotics may offer several benefits over systemic therapy; however, the outcomes and current practices of such treatments are poorly described in the literature. OBJECTIVE: To describe current practices and outcomes of patients receiving intraventricular antibiotic treatment for CNS infections in neurological intensive care units of academic medical centers nationwide. METHODS: A retrospective cohort study was conducted on patients admitted to intensive care units who received IVT antibiotic treatment at participating centers in the USA between January 01, 2003, and December 31, 2013. Clinical and laboratory parameters, microbiology, surgical and antimicrobial management, and treatment outcomes were collected and described. RESULTS: Of the 105 patients included, all received systemic antimicrobial therapy along with at least one dose of IVT antimicrobial agents. Intraventricular vancomycin was used in 52.4% of patients. The average dose was 12.2 mg/day for a median duration of 5 days. Intraventricular aminoglycosides were used in 47.5% of the patients, either alone or in combination with IVT vancomycin. The average dose of gentamicin/tobramycin was 6.7 mg/day with a median duration of 6 days. Overall mortality was 18.1%. Cerebrospinal fluid (CSF) culture sterilization occurred in 88.4% of the patients with a rate of recurrence or persistence of positive cultures of 9.5%. CONCLUSION: Intraventricular antimicrobial agents resulted in a high CSF sterilization rate. Contemporary use of this route typically results in a treatment duration of less than a week. Prospective studies are needed to establish the optimal patient population, as well as the efficacy and safety of this route of administration.


Asunto(s)
Antibacterianos/administración & dosificación , Ventriculitis Cerebral/tratamiento farmacológico , Líquido Cefalorraquídeo/efectos de los fármacos , Líquido Cefalorraquídeo/microbiología , Cuidados Críticos/estadística & datos numéricos , Meningitis/tratamiento farmacológico , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Adulto , Anciano , Aminoglicósidos/administración & dosificación , Ventriculitis Cerebral/líquido cefalorraquídeo , Femenino , Gentamicinas/administración & dosificación , Humanos , Inyecciones Intraventriculares , Unidades de Cuidados Intensivos/estadística & datos numéricos , Masculino , Meningitis/líquido cefalorraquídeo , Persona de Mediana Edad , Estudios Retrospectivos , Tobramicina/administración & dosificación , Vancomicina/administración & dosificación
15.
Crit Care Nurs Q ; 42(2): 148-164, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30807339

RESUMEN

Acute blood pressure control after a cerebrovascular event is integral in the immediate care of these patients to preserve perfusion to ischemic areas and prevent intracerebral bleeding. The majority of patients with ischemic stroke or intracerebral hemorrhage (ICH) present with preexisting hypertension and therefore require a treatment plan after the acute phase. The presence of chronic hypertension after ICH has often been discussed as a modifiable risk factor for recurrent events. Clinical evidence is relatively lacking for clinicians to understand the extent of blood pressure lowering and the optimal agents to use in this setting. Limited data exist describing the long-term management of hypertension in patients after cerebrovascular events. This review provides nurses with a summary of the available literature on long-term blood pressure management to minimize the risk of secondary ICH and ischemic stroke. It focuses on oral antihypertensive medications available in the United States that may be utilized to manage chronic hypertension immediately after the postacute phase of care to lower blood pressure and to improve long-term outcomes.


Asunto(s)
Antihipertensivos/administración & dosificación , Presión Sanguínea/efectos de los fármacos , Hemorragia Cerebral/tratamiento farmacológico , Hipertensión/tratamiento farmacológico , Antihipertensivos/farmacología , Humanos , Factores de Riesgo , Accidente Cerebrovascular/prevención & control
16.
J Stroke Cerebrovasc Dis ; 28(11): 104313, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31405792

RESUMEN

BACKGROUND: Fever occurs in the majority of subarachnoid hemorrhage (SAH) patients. Nearly 50% of SAH patients have noninfectious fevers. Data are lacking describing the effects of fever burden in the SAH patient population. METHODS: This was a single-center, retrospective observational cohort study in patients more or equal to 18 years of age with a diagnosis of nontraumatic SAH admitted to an ICU between January 1, 2010 and September 1, 2015. Exclusion criteria were SAH secondary to trauma or admission for more than 48 hours. Temperature measurements, demographic data, and other pertinent information were collected from Day 0 to Day 13. Daily fever burden was calculated for each patient by calculating an area under the curve. RESULTS: A total of 194 subjects were included. The mean study period maximum temperature (Tmax) for all 194 patients was 40.8 ± 0.83°C. The mean overall fever burden for all 194 patients was 89.2 ± 99.59°C h more than 37°C. The overall fever burden peaked on day 5 and declined thereafter. Fever burden, Tmax, and length of stay in the hospital were all significantly associated with receipt of antibiotics. Only Tmax was associated with poor outcome. The 31 patients who had fever but no identified cause of infection received 1000 doses of antibiotics or 32.25 doses per patient. CONCLUSION: Fever is common in SAH patients and is associated with antibiotic use, infection, vasospasm, and poor outcome. Some SAH patients may receive antibiotics unnecessarily for noninfectious fever. Clinicians should consider using site-specific parameters related to infection rather than systemic symptoms such as fever to evaluate infection in SAH patients.


Asunto(s)
Antibacterianos/uso terapéutico , Regulación de la Temperatura Corporal/efectos de los fármacos , Fiebre/tratamiento farmacológico , Prescripción Inadecuada , Hemorragia Subaracnoidea/complicaciones , Programas de Optimización del Uso de los Antimicrobianos , Femenino , Fiebre/microbiología , Fiebre/fisiopatología , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Factores de Tiempo , Resultado del Tratamiento
17.
Hosp Pharm ; 54(4): 246-249, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31320774

RESUMEN

Background: Preceptor development is a focus of pharmacy residency programs across the country. Graduation from residency into the role of preceptor can be a challenge, as it is one of many transitions junior practitioners make in their early careers. Literature in recent years has brought attention to the need to establish preceptor development programs that adequately allow newer preceptors to develop their skills in experiential education, for both pharmacy residents and students. Furthermore, many preceptor development programs as implemented are often didactic in nature, and include readings, webinars, and other passive learning regarding the art of precepting. Objective: Given the need to develop a preceptor development program in our service line that met the needs of preceptors-in-training and full preceptors, we offer a description of our preceptor development program in the intensive care unit. Methods: We focused on active development of preceptor skills for multiple layers of resident and student learners. In addition, this model incorporated instructing, modeling, coaching, and facilitating, as the relationship between full preceptor and preceptor-in-training evolved. It also offered the opportunity for real-time feedback and discussion on precepting performance. Conclusions: We describe our coprecepting model as an opportunity that succeeded for us in helping to transition our preceptors-in-training to full preceptors. It met the needs of our department, staff, and patients, and we believe it has the potential to be valuable as a tool extrapolated to the preceptor development programs of other institutions.

18.
Blood ; 128(9): 1282-9, 2016 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-27235135

RESUMEN

In addition to mutations in ITG2B or ITGB3 genes that cause defective αIIbß3 expression and/or function in Glanzmann's thrombasthenia patients, platelet dysfunction can be a result of genetic variability in proteins that mediate inside-out activation of αIIbß3 The RASGRP2 gene is strongly expressed in platelets and neutrophils, where its encoded protein CalDAG-GEFI facilitates the activation of Rap1 and subsequent activation of integrins. We used next-generation sequencing (NGS) and whole-exome sequencing (WES) to identify 2 novel function-disrupting mutations in RASGRP2 that account for bleeding diathesis and platelet dysfunction in 2 unrelated families. By using a panel of 71 genes, we identified a homozygous change (c.1142C>T) in exon 10 of RASGRP2 in a 9-year-old child of Chinese origin (family 1). This variant led to a p.Ser381Phe substitution in the CDC25 catalytic domain of CalDAG-GEFI. In 2 Spanish siblings from family 2, WES identified a nonsense homozygous variation (c.337C>T) (p.Arg113X) in exon 5 of RASGRP2 CalDAG-GEFI expression was markedly reduced in platelets from all patients, and by using a novel in vitro assay, we found that the nucleotide exchange activity was dramatically reduced in CalDAG-GEFI p.Ser381Phe. Platelets from homozygous patients exhibited agonist-specific defects in αIIbß3 integrin activation and aggregation. In contrast, α- and δ-granule secretion, platelet spreading, and clot retraction were not markedly affected. Integrin activation in the patients' neutrophils was also impaired. These patients are the first cases of a CalDAG-GEFI deficiency due to homozygous RASGRP2 mutations that are linked to defects in both leukocyte and platelet integrin activation.


Asunto(s)
Plaquetas/metabolismo , Exones , Factores de Intercambio de Guanina Nucleótido , Mutación Missense , Activación Plaquetaria/genética , Trombastenia , Proteínas de Unión al GTP rap1/metabolismo , Sustitución de Aminoácidos , Plaquetas/patología , Niño , Activación Enzimática/genética , Femenino , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Integrina beta3/genética , Integrina beta3/metabolismo , Masculino , Persona de Mediana Edad , Glicoproteína IIb de Membrana Plaquetaria/genética , Glicoproteína IIb de Membrana Plaquetaria/metabolismo , Vesículas Secretoras/genética , Vesículas Secretoras/metabolismo , Trombastenia/genética , Trombastenia/metabolismo , Trombastenia/patología
19.
Platelets ; 29(1): 84-86, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28726538

RESUMEN

Congenital platelet function disorders are often the result of defects in critical signal transduction pathways required for platelet adhesion and clot formation. Mutations affecting RASGRP2, the gene encoding the Rap GTPase activator, CalDAG-GEFI, give rise to a novel, and rare, group of platelet signal transduction abnormalities. We here report platelet function studies for two brothers (P1 and P2) expressing a novel variant of RASGRP2, CalDAG-GEFI(p.Gly305Asp). P1 and P2 have a lifelong history of bleeding with severe epistaxis successfully treated with platelet transfusions or rFVIIa. Other bleedings include extended hemorrhage from minor wounds. Platelet counts and plasma coagulation were normal, as was αIIbß3 and GPIb expression on the platelet surface. Aggregation of patients' platelets was significantly impaired in response to select agonists including ADP, epinephrine, collagen, and calcium ionophore A23187. Integrin αIIbß3 activation and granule release were also impaired. CalDAG-GEFI protein expression was markedly reduced but not absent. Homology modeling places the Gly305Asp substitution at the GEF-Rap1 interface, suggesting that the mutant protein has very limited catalytic activity. In summary, we here describe a novel mutation in RASGRP2 that affects both expression and function of CalDAG-GEFI and that causes impaired platelet adhesive function and significant bleeding in humans.


Asunto(s)
Trastornos de las Plaquetas Sanguíneas/sangre , Trastornos de las Plaquetas Sanguíneas/genética , Plaquetas/metabolismo , Factores de Intercambio de Guanina Nucleótido/genética , Hemorragia/etiología , Biomarcadores , Trastornos de las Plaquetas Sanguíneas/complicaciones , Niño , Índices de Eritrocitos , Factores de Intercambio de Guanina Nucleótido/química , Factores de Intercambio de Guanina Nucleótido/metabolismo , Hemorragia/diagnóstico , Humanos , Masculino , Modelos Moleculares , Linaje , Fenotipo , Agregación Plaquetaria/genética , Recuento de Plaquetas , Conformación Proteica , Transducción de Señal
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA