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1.
J Infect ; 87(5): 392-402, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37690669

RESUMEN

OBJECTIVES: To evaluate the efficacy and safety of molnupiravir for intra-household post-exposure prophylaxis (PEP) of COVID-19. METHODS: MOVe-AHEAD was a randomized, controlled, double-blind, phase 3 trial comparing molnupiravir (800 mg twice daily for 5 days) with placebo. Eligible participants were adult, unvaccinated, asymptomatic household contacts of patients with laboratory-confirmed COVID-19. The primary efficacy endpoint was the incidence of COVID-19 through day 14 in modified intention-to-treat (MITT) participants (those who received ≥1 dose of study intervention) without detectable SARS-CoV-2 at baseline, termed the MITT-VN population. Superiority of molnupiravir was prespecified as a stratified one-sided p-value of <0.0249 for the treatment difference in this endpoint. RESULTS: The MITT population comprised 763 participants randomized to molnupiravir and 764 to placebo; 83.6% had anti-SARS-CoV-2 antibodies at baseline. In the MITT-VN population, COVID-19 rates through day 14 were 6.5% with molnupiravir and 8.5% with placebo (one-sided p-value: 0.0848). In the molnupiravir arm, 25/35 of confirmed COVID-19 events (71.4%) occurred after completion of treatment (versus 17/49 [34.7%] for placebo). Adverse event rates were low and similar between molnupiravir and placebo. CONCLUSIONS: Molnupiravir was well-tolerated but did not meet the prespecified superiority criterion, possibly influenced in part by the high pre-existing immunity in the trial population.

3.
Am J Emerg Med ; 68: 119-123, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36972634

RESUMEN

BACKGROUND: ß-lactam antibiotics are amongst the most commonly prescribed medications in the Emergency Department (ED) due to their role in empiric sepsis therapy; however, inferior therapeutic options are often utilized due to a reported allergy; penicillin (PCN) being most frequent. In the United States, 10% of the population endorses an allergic reaction to PCN while <1% experience IgE-mediated reactions. This study aimed to evaluate the frequency and outcome of patients in the ED whose PCN allergies were challenged with ß-lactam antibiotics. METHODS: We conducted a retrospective chart review of patients in the ED at an academic medical center aged ≥18, and who received a ß-lactam despite a reported PCN allergy between January 2015 and December 2019. Patients who did not receive a ß-lactam or did not report a PCN allergy prior to administration were excluded. The primary outcome was the frequency of IgE-mediated reactions in response to ß-lactam administration. A secondary outcome assessed the frequency of continuation of ß-lactams upon admission from the ED. RESULTS: 819 patients were included (66% female) with prior reported PCN reactions: hives (22.5%), rash (15.4%), swelling (6.2%), anaphylaxis (3.5%), other (12.1%), or undocumented on medical electronic record (40.3%). No patients experienced an IgE-mediated reaction to the ß-lactam administered in the ED. Previously reported allergies had no effect on the continuation of ß-lactams when admitted or discharged (OR: 1, 95% CI: 0.7-1.44). Patients who had a history of an IgE-mediated penicillin allergy were frequently continued (77%) on a ß-lactam after leaving the ED via admission or discharge. CONCLUSION: ß-lactam administration in patients with previously reported PCN allergies did not result in any IgE-mediated reactions nor in an increase in adverse reactions. Our data contributes to the body of evidence that supports the administration of ß-lactams to patients with documented PCN allergies.


Asunto(s)
Hipersensibilidad a las Drogas , Urticaria , Humanos , Femenino , Masculino , Antibacterianos/efectos adversos , Estudios Retrospectivos , Penicilinas/efectos adversos , beta-Lactamas/efectos adversos , Hipersensibilidad a las Drogas/epidemiología , Hipersensibilidad a las Drogas/etiología , Monobactamas , Urticaria/tratamiento farmacológico , Servicio de Urgencia en Hospital , Inmunoglobulina E
4.
Sci Adv ; 8(32): eabq1700, 2022 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-35947667

RESUMEN

The size and shape of semiconductor nanocrystals govern their optical and electronic properties. Liquid cell transmission electron microscopy (LCTEM) is an emerging tool that can directly visualize nanoscale chemical transformations and therefore inform the precise synthesis of nanostructures with desired functions. However, it remains difficult to controllably investigate the reactions of semiconductor nanocrystals with LCTEM, because of the highly reactive environment formed by radiolysis of liquid. Here, we harness the radiolysis processes and report the single-particle etching trajectories of prototypical semiconductor nanomaterials with well-defined crystalline facets. Lead selenide nanocubes represent an isotropic structure that retains the cubic shape during etching via a layer-by-layer mechanism. The anisotropic arrow-shaped cadmium selenide nanorods have polar facets terminated by either cadmium or selenium atoms, and the transformation trajectory is driven by etching the selenium-terminated facets. LCTEM trajectories reveal how nanoscale shape transformations of semiconductors are governed by the reactivity of specific facets in liquid environments.

5.
Lancet Infect Dis ; 22(5): 611-621, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35286843

RESUMEN

BACKGROUND: Non-antiviral therapeutic options are required for the treatment of hospitalised patients with COVID-19. CD24Fc is an immunomodulator with potential to reduce the exaggerated inflammatory response to tissue injuries. We aimed to evaluate the safety and efficacy of CD24Fc in hospitalised adults with COVID-19 receiving oxygen support. METHODS: We conducted a randomised, double-blind, placebo-controlled, phase 3 study at nine medical centres in the USA. Hospitalised patients (age ≥18 years) with confirmed SARS-CoV-2 infection who were receiving oxygen support and standard of care were randomly assigned (1:1) by site-stratified block randomisation to receive a single intravenous infusion of CD24Fc 480 mg or placebo. The study funder, investigators, and patients were masked to treatment group assignment. The primary endpoint was time to clinical improvement over 28 days, defined as time that elapsed between a baseline National Institute of Allergy and Infectious Diseases ordinal scale score of 2-4 and reaching a score of 5 or higher or hospital discharge. The prespecified primary interim analysis was done when 146 participants reached the time to clinical improvement endpoint. Efficacy was assessed in the intention-to-treat population. Safety was assessed in the as-treated population. This study is registered with ClinicalTrials.gov, NCT04317040. FINDINGS: Between April 24 and Sept 22, 2020, 243 hospitalised patients were assessed for eligibility and 234 were enrolled and randomly assigned to receive CD24Fc (n=116) or placebo (n=118). The prespecified interim analysis was done when 146 participants reached the time to clinical improvement endpoint among 197 randomised participants. In the interim analysis, the 28-day clinical improvement rate was 82% (81 of 99) for CD24Fc versus 66% (65 of 98) for placebo; median time to clinical improvement was 6·0 days (95% CI 5·0-8·0) in the CD24Fc group versus 10·0 days (7·0-15·0) in the placebo group (hazard ratio [HR] 1·61, 95% CI 1·16-2·23; log-rank p=0·0028, which crossed the prespecified efficacy boundary [α=0·0147]). 37 participants were randomly assigned after the interim analysis data cutoff date; among the 234 randomised participants, median time to clinical improvement was 6·0 days (95% CI 5·0-9·0) in the CD24Fc group versus 10·5 days (7·0-15·0) in the placebo group (HR 1·40, 95% CI 1·02-1·92; log-rank p=0·037). The proportion of participants with disease progression within 28 days was 19% (22 of 116) in the CD24Fc group versus 31% (36 of 118) in the placebo group (HR 0·56, 95% CI 0·33-0·95; unadjusted p=0·031). The incidences of adverse events and serious adverse events were similar in both groups. No treatment-related adverse events were observed. INTERPRETATION: CD24Fc is generally well tolerated and accelerates clinical improvement of hospitalised patients with COVID-19 who are receiving oxygen support. These data suggest that targeting inflammation in response to tissue injuries might provide a therapeutic option for patients hospitalised with COVID-19. FUNDING: Merck & Co, National Cancer Institute, OncoImmune.


Asunto(s)
Tratamiento Farmacológico de COVID-19 , Adolescente , Adulto , Método Doble Ciego , Humanos , Factores Inmunológicos/efectos adversos , Oxígeno , SARS-CoV-2 , Resultado del Tratamiento
6.
Pharmacotherapy ; 42(3): 268-271, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35075683

RESUMEN

We report a 50-year-old Caucasian male with a complicated past medical history who developed extensive polymicrobial osteomyelitis, including a carbapenem-resistant Acinetobacter baumannii (CRAB). In order to streamline therapy, the patient received compassionate use cefiderocol for 6 weeks which was well tolerated. In addition, the patient's infection was considered cured at end of treatment. Few cases on the use of prolonged cefiderocol for treatment of osteomyelitis due to CRAB have been published. Our patient did not report adverse reactions, nor did he develop laboratory abnormalities which were assessed throughout and at the end of the 6-week course.


Asunto(s)
Acinetobacter baumannii , Osteomielitis , Antibacterianos/uso terapéutico , Carbapenémicos/uso terapéutico , Cefalosporinas , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Osteomielitis/tratamiento farmacológico , Cefiderocol
8.
Nano Lett ; 21(9): 3731-3737, 2021 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-33719451

RESUMEN

Maintaining fast charging capability at low temperatures represents a significant challenge for supercapacitors. The performance of conventional porous carbon electrodes often deteriorates quickly with the decrease of temperature due to sluggish ion and charge transport. Here we fabricate a 3D-printed multiscale porous carbon aerogel (3D-MCA) via a unique combination of chemical methods and the direct ink writing technique. 3D-MCA has an open porous structure with a large surface area of ∼1750 m2 g-1. At -70 °C, the symmetric device achieves outstanding capacitance of 148.6 F g-1 at 5 mV s-1. Significantly, it retains a capacitance of 71.4 F g-1 at a high scan rate of 200 mV s-1, which is 6.5 times higher than the non-3D printed MCA. These values rank among the best results reported for low temperature supercapacitors. These impressive results highlight the essential role of open porous structures for preserving capacitive performance at ultralow temperatures.

9.
Am J Ther ; 28(1): e14-e18, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-31714256

RESUMEN

BACKGROUND: Aztreonam is not a preferred empiric antibiotic because of variable susceptibilities compared with alternative agents. In addition, it has no Gram-positive activity, necessitating coadministration with vancomycin when used empirically, and is more costly when compared with other Gram-negative active agents. Aztreonam is often given to patients with a reported penicillin allergy without further investigation into the reaction or other relevant allergy information. STUDY QUESTION: How frequently is aztreonam being used inappropriately? STUDY DESIGN: We conducted a retrospective chart review at an academic medical center to assess the appropriateness of our aztreonam use. MEASURES AND OUTCOMES: Our primary outcome was frequency of appropriate aztreonam use, based on a true IgE-mediated allergy reported for each patient. We evaluated whether the patients had tolerated a beta-lactam in the past, and what the reported allergic reaction was. RESULTS: We included 165 patients and found that 46.7% of our aztreonam use was inappropriate, based on previous use of a beta-lactam, or no documentation of an IgE-mediated response. Of the patients with a documented beta-lactam allergy, 63 (38.2%) patients had no allergy manifestation listed, and 37 (22.4%) patients had a non-IgE-mediated allergy manifestation. Of the total population, 61 (37%) patients had tolerated a beta-lactam in the past. CONCLUSIONS: Aztreonam should be avoided, except in the case of a true IgE-mediated allergic reaction. Our goal was to reduce the inappropriate use of aztreonam at our institution by one or more of the following: educating providers, reviewing aztreonam orders, requiring answering of order questions, or requiring an indication for use. Penicillin skin testing and desensitization are options as well.


Asunto(s)
Aztreonam , Hipersensibilidad a las Drogas , Antibacterianos/efectos adversos , Aztreonam/efectos adversos , Hipersensibilidad a las Drogas/tratamiento farmacológico , Hipersensibilidad a las Drogas/epidemiología , Hipersensibilidad a las Drogas/etiología , Humanos , Penicilinas , Estudios Retrospectivos , beta-Lactamas
10.
Am J Epidemiol ; 188(8): 1569-1577, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31063192

RESUMEN

Effect estimates from randomized trials and observational studies might not be directly comparable because of differences in study design, other than randomization, and in data analysis. We propose a 3-step procedure to facilitate meaningful comparisons of effect estimates from randomized trials and observational studies: 1) harmonization of the study protocols (eligibility criteria, treatment strategies, outcome, start and end of follow-up, causal contrast) so that the studies target the same causal effect, 2) harmonization of the data analysis to estimate the causal effect, and 3) sensitivity analyses to investigate the impact of discrepancies that could not be accounted for in the harmonization process. To illustrate our approach, we compared estimates of the effect of immediate with deferred initiation of antiretroviral therapy in individuals positive for the human immunodeficiency virus from the Strategic Timing of Antiretroviral Therapy (START) randomized trial and the observational HIV-CAUSAL Collaboration.


Asunto(s)
Antirretrovirales/uso terapéutico , Métodos Epidemiológicos , Infecciones por VIH/tratamiento farmacológico , Estudios Observacionales como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad
11.
Transpl Infect Dis ; 20(6): e12995, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30199584

RESUMEN

INTRODUCTION: Left ventricular assist device (LVAD) infections are common, and the consequences of LVAD infections on orthotopic heart transplantation (OHT) outcomes are not well described. AIMS: The aim of this study was to describe clinical characteristics and evaluate risk factors for developing LVAD infections, and examine outcomes of LVAD-specific infections (VSI) after OHT. METHODS: We retrospectively investigated the records of 74 consecutive patients at two institutions who had undergone LVAD placement and subsequent OHT between January 2007 and December 2012. RESULTS: Forty-six of 74 (62%) LVAD recipients who underwent OHT had pre-transplant infections, and 18 (24%) had LVAD-specific infection (VSI), of which 71% were caused by gram-negative organisms. Of pre-transplant non-LVAD infections, Clostridium difficile infection (CDI) was the most common (26%) followed by urinary tract infection (UTI, 16%) and pneumonia (PNA 15%). Univariate analysis comparing subjects with VSI to those without VSI showed a significant association with time spent outside the hospital prior to transplantation (median 231.8 days vs 142.2 days, P < 0.03) and total time between VAD placement and OHT (244.0 days and 150.5 days, P < 0.002). Logistic regression was performed and significant predictors for VAD-related infection were age and the presence of diabetes, with type of device as an effect modifier. Six months post-OHT survival was not significantly affected by the presence of VSI prior to transplant. There was a trend toward an association between the presence of any infection and post-transplant rejection (P < 0.09). There were 10 post-transplant deaths by 6 months. Of these deaths, 4/10 (40%) were cardiopulmonary and 6/10 (60%) were related to infections. CONCLUSIONS: Advanced age and presence of diabetes were predictors of VSI, as well as type of VAD device, although device choice is likely affected by many clinical factors including age and comorbidities, as well as institution-specific preferences. VSI was not associated with a decrease in 6-month post-OHT survival. However, infections remain the major causes of death by 6 months post-transplant. Certain infections are associated with an increased risk of rejection, which merits further investigation.


Asunto(s)
Rechazo de Injerto/epidemiología , Insuficiencia Cardíaca/cirugía , Trasplante de Corazón/efectos adversos , Corazón Auxiliar/efectos adversos , Infecciones/epidemiología , Complicaciones Posoperatorias/epidemiología , Adulto , Factores de Edad , Diabetes Mellitus/epidemiología , Femenino , Humanos , Infecciones/microbiología , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia , Resultado del Tratamiento
12.
Clin Infect Dis ; 65(9): 1542-1550, 2017 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-29020184

RESUMEN

BACKGROUND: Patients with human immunodeficiency virus (HIV) and/or chronic hepatitis C virus (HCV) infection may be prescribed statins as treatment for metabolic/cardiovascular disease, but it remains unclear if the risk of acute liver injury (ALI) is increased for statin initiators compared to nonusers in groups classified by HIV/HCV status. METHODS: We conducted a cohort study to compare rates of ALI in statin initiators vs nonusers among 7686 HIV/HCV-coinfected, 8155 HCV-monoinfected, 17739 HIV-monoinfected, and 36604 uninfected persons in the Veterans Aging Cohort Study (2000-2012). We determined development of (1) liver aminotransferases >200 U/L, (2) severe ALI (coagulopathy with hyperbilirubinemia), and (3) death, all within 18 months. Cox regression was used to determine propensity score-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of outcomes in statin initiators compared to nonusers across the groups. RESULTS: Among HIV/HCV-coinfected patients, statin initiators had lower risks of aminotransferase levels >200 U/L (HR, 0.66 [95% CI, .53-.83]), severe ALI (HR, 0.23 [95% CI, .12-.46]), and death (HR, 0.36 [95% CI, .28-.46]) compared with statin nonusers. In the setting of chronic HCV alone, statin initiators had reduced risks of aminotransferase elevations (HR, 0.57 [95% CI, .45-.72]), severe ALI (HR, 0.15 [95% CI, .06-.37]), and death (HR, 0.42 [95% CI, .32-.54]) than nonusers. Among HIV-monoinfected patients, statin initiators had lower risks of aminotransferase increases (HR, 0.52 [95% CI, .40-.66]), severe ALI (HR, 0.26 [95% CI, .13-.55]), and death (HR, 0.19 [95% CI, .16-.23]) compared with nonusers. Results were similar among uninfected persons. CONCLUSIONS: Regardless of HIV and/or chronic HCV status, statin initiators had a lower risk of ALI and death within 18 months compared with statin nonusers.


Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/epidemiología , Infecciones por VIH/epidemiología , Hepatitis C Crónica/epidemiología , Inhibidores de Hidroximetilglutaril-CoA Reductasas/efectos adversos , Enfermedad Hepática Inducida por Sustancias y Drogas/mortalidad , Femenino , Infecciones por VIH/complicaciones , Hepatitis C Crónica/complicaciones , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo
13.
Antivir Ther ; 21(2): 175-80, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26308882

RESUMEN

Very high baseline HIV-1 RNA viral loads require potent and robust antiretroviral regimens to achieve virological suppression. The coformulated single tablet regimen of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF) is recommended by the US Department of Health and Human Services for the treatment of HIV-1 in treatment-naive adults and adolescents regardless of baseline CD4(+) T-cell count and viral load. We report two cases of HIV-infected, treatment-naive patients, with baseline HIV-1 RNA viral loads >1,000,000 copies/ml who were initiated on the single tablet regimen EVG/COBI/FTC/TDF, but failed to attain viral load suppression and developed resistance to the components of EVG/COBI/FTC/TDF.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Combinación Elvitegravir, Cobicistat, Emtricitabina y Fumarato de Tenofovir Disoproxil/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , VIH-1/genética , ARN Viral/sangre , Carga Viral , Fármacos Anti-VIH/administración & dosificación , Combinación Elvitegravir, Cobicistat, Emtricitabina y Fumarato de Tenofovir Disoproxil/administración & dosificación , Femenino , Infecciones por VIH/sangre , Infecciones por VIH/virología , Humanos , Masculino , Persona de Mediana Edad
14.
Ann Epidemiol ; 24(6): 418-23, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24703196

RESUMEN

PURPOSE: Few population-based studies have estimated the number of persons diagnosed with chronic hepatitis B (CHB) infection in the United States. Our objective was to estimate the prevalence of diagnosed CHB infection among persons enrolled in the U.S. Medicaid programs of California, Florida, New York, Ohio, and Pennsylvania between 2000 and 2007. As part of our analyses, we confirmed the accuracy of CHB diagnoses within the Medicaid database. METHODS: CHB infection was defined by the presence of two outpatients CHB diagnoses recorded more than 6 months apart. Two clinicians reviewed the medical records of a random sample of patients who met this definition to confirm the diagnosis, which enabled calculation of the positive predictive value (PPV). The period prevalence of diagnosed CHB infection among Medicaid enrollees with at least 6 months of membership from 2000 to 2007 was then estimated, adjusting for both the PPV and estimated sensitivity of our definition of CHB infection. RESULTS: The definition of CHB infection accurately identified clinician-confirmed cases (PPV, 96.3%; 95% confidence interval [CI], 87.3-99.5). Using this definition, 31,046 cases of CHB were diagnosed among 31,358,010 eligible Medicaid members from the five states (prevalence, 9.9 [95% CI, 9.8-10.0] per 10,000). Adjusting for the PPV and estimated sensitivity of our CHB definition, the prevalence of diagnosed CHB infection was 15.6 (95% CI, 15.4-15.7) per 10,000. CONCLUSIONS: Two outpatient CHB diagnoses recorded more than 6 months apart validly identified clinician-confirmed CHB. The prevalence of diagnosed CHB infection among U.S. Medicaid enrollees was 15.6 per 10,000.


Asunto(s)
Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Hepatitis B Crónica/diagnóstico , Hepatitis B Crónica/epidemiología , Tamizaje Masivo/estadística & datos numéricos , Medicaid/estadística & datos numéricos , Adulto , Anciano , Intervalos de Confianza , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Prevalencia , Estudios Retrospectivos , Factores de Riesgo , Factores Socioeconómicos , Estados Unidos/epidemiología , Adulto Joven
15.
J Hepatol ; 61(2): 210-8, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24713185

RESUMEN

BACKGROUND & AIMS: Chronic hepatitis B (CHB) infection is associated with reduced bone mineral density, but its association with fractures is unknown. Our objectives were to determine whether untreated or treated CHB-infected persons are at increased risk for hip fracture compared to uninfected persons. METHODS: We conducted a cohort study among 18,796 untreated CHB-infected, 7777 treated CHB-infected, and 979,751 randomly sampled uninfected persons within the U.S. Medicaid populations of California, Florida, New York, Ohio, and Pennsylvania (1999-2007). CHB infection was defined by two CHB diagnoses recorded >6 months apart and was classified as treated if a diagnosis was recorded and antiviral therapy was dispensed. After propensity score matching of CHB-infected and uninfected persons, Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) of incident hip fracture in: (1) untreated CHB-infected vs. uninfected, and (2) treated CHB-infected vs. uninfected patients. RESULTS: Untreated CHB-infected patients of black race had a higher rate of hip fracture than uninfected black persons (HR, 2.55 [95% CI, 1.42-4.58]). Compared to uninfected persons, relative hazards of hip fracture were increased for untreated white (HR, 1.26 [95% CI, 0.98-1.62]) and Hispanic (HR, 1.36 [95% CI, 0.77-2.40]) CHB-infected patients, and treated black (HR, 3.09 [95% CI, 0.59-16.22]) and white (HR, 1.90 [95% CI, 0.81-4.47]) CHB-infected patients, but these associations were not statistically significant. CONCLUSIONS: Among U.S. Medicaid enrollees, untreated CHB-infected patients of black race had a higher risk of hip fracture than uninfected black persons.


Asunto(s)
Hepatitis B Crónica/complicaciones , Fracturas de Cadera/etiología , Adulto , Anciano , Estudios de Cohortes , Femenino , Hepatitis B Crónica/tratamiento farmacológico , Fracturas de Cadera/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Riesgo
16.
Cereb Cortex ; 18(4): 904-14, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17675369

RESUMEN

Two studies were performed that compared a "Paired" condition in which participants studied paired associates with a "Generated" condition in which participants completed word fragments to produce paired associates. In both tasks, participants were responsible for memory of the material either studied or generated. The experiments revealed significant differences between the responses of a predefined prefrontal region and a predefined parietal region. The parietal region responded more in the Generated condition than the Paired condition, whereas there was no difference in the prefrontal region. On the other hand, the prefrontal region responded to the delay between study and test in both the Paired and Generated conditions, whereas the parietal region only responded to delay in the Generated condition. This pattern of results is consistent with the hypothesis that the parietal region is responsive to changes in problem representation and the prefrontal region to retrieval operations. An information-processing model embodying these assumptions was fit to the blood oxygen level-dependent responses in these regions.


Asunto(s)
Aprendizaje por Asociación/fisiología , Imagen por Resonancia Magnética , Modelos Neurológicos , Lóbulo Parietal/fisiología , Corteza Prefrontal/fisiología , Adolescente , Adulto , Femenino , Giro del Cíngulo/fisiología , Humanos , Masculino , Recuerdo Mental/fisiología , Corteza Motora/fisiología , Lóbulo Occipital/fisiología , Tiempo de Reacción/fisiología
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