RESUMEN
OBJECTIVE: To investigate the effectiveness of a multicomponent breastfeeding support intervention on breastfeeding prevalence at 3 months among women with a body mass index (BMI) >25 kg/m2. DESIGN: Multicentre multicomponent randomised controlled trial. SETTING: Four maternity centres in Ireland. POPULATION: A total of 225 primiparous women and their nominated support partners. Participants were aged 18 years and over, with BMI ≥25 kg/m2, carrying a singleton pregnancy and without contraindication for breastfeeding. METHODS: The intervention included an antenatal group breastfeeding education session for participants and their support partners, followed by a planned postnatal breastfeeding assessment and telephone support for up to 6 weeks by a lactation consultant. MAIN OUTCOME MEASURES: Any breastfeeding at 3 months postpartum. RESULTS: Any breastfeeding prevalence was 68.7% (n = 68) in the intervention group and 62.1% (n = 59) in the control group at 3 months postpartum (odds ratio 1.33, 95% confidence interval 0.72-2.46, p = 0.36). Any and exclusive breastfeeding rates did not significantly differ at any other time point. More women in the control group accessed support from private lactation consultants (intervention 23.5% [n = 12], control 45.3% [n = 24], p = 0.02). CONCLUSIONS: The control group had higher than expected breastfeeding rates, and the study found no evidence of effect on the primary outcome. Providing comprehensive education and support for women intending to breastfeed remains of paramount importance.
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Índice de Masa Corporal , Lactancia Materna , Humanos , Femenino , Lactancia Materna/estadística & datos numéricos , Adulto , Embarazo , Irlanda/epidemiología , Apoyo Social , Atención Posnatal/métodos , Educación del Paciente como Asunto/métodos , Recién NacidoRESUMEN
OBJECTIVE: To investigate if magnetic resonance imaging (MRI) is an accurate predictor for death or moderate-severe disability at 18-22 months of age among infants with neonatal encephalopathy in a trial of cooling initiated at 6-24 hours. STUDY DESIGN: Subgroup analysis of infants ≥36 weeks of gestation with moderate-severe neonatal encephalopathy randomized at 6-24 postnatal hours to hypothermia or usual care in a multicenter trial of late hypothermia. MRI scans were performed per each center's practice and interpreted by 2 central readers using the Eunice Kennedy Shriver National Institute of Child Health and Human Development injury score (6 levels, normal to hemispheric devastation). Neurodevelopmental outcomes were assessed at 18-22 months of age. RESULTS: Of 168 enrollees, 128 had an interpretable MRI and were seen in follow-up (n = 119) or died (n = 9). MRI findings were predominantly acute injury and did not differ by cooling treatment. At 18-22 months, death or severe disability occurred in 20.3%. No infant had moderate disability. Agreement between central readers was moderate (weighted kappa 0.56, 95% CI 0.45-0.67). The adjusted odds of death or severe disability increased 3.7-fold (95% CI 1.8-7.9) for each increment of injury score. The area under the curve for severe MRI patterns to predict death or severe disability was 0.77 and the positive and negative predictive values were 36% and 100%, respectively. CONCLUSIONS: MRI injury scores were associated with neurodevelopmental outcome at 18-22 months among infants in the Late Hypothermia Trial. However, the results suggest caution when using qualitative interpretations of MRI images to provide prognostic information to families following perinatal hypoxia-ischemia. TRIAL REGISTRATION: Clinicaltrials.gov: NCT00614744.
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Discapacidades del Desarrollo/diagnóstico por imagen , Hipoxia-Isquemia Encefálica/terapia , Imagen por Resonancia Magnética , Discapacidades del Desarrollo/etiología , Femenino , Humanos , Hipotermia Inducida/efectos adversos , Hipotermia Inducida/métodos , Hipoxia-Isquemia Encefálica/complicaciones , Hipoxia-Isquemia Encefálica/diagnóstico por imagen , Lactante , Recién Nacido , Recien Nacido Prematuro , Masculino , Valor Predictivo de las Pruebas , Índice de Severidad de la EnfermedadRESUMEN
To realize the full potential of emerging nucleic acid therapies, there is a need for effective delivery agents to transport cargo to cells of interest. Protein materials exhibit several unique properties, including biodegradability, biocompatibility, ease of functionalization via recombinant and chemical modifications, among other features, which establish a promising basis for therapeutic nucleic acid delivery systems. In this review, we highlight progress made in the use of non-viral protein-based nanoparticles for nucleic acid delivery in vitro and in vivo, while elaborating on key physicochemical properties that have enabled the use of these materials for nanoparticle formulation and drug delivery. To conclude, we comment on the prospects and unresolved challenges associated with the translation of protein-based nucleic acid delivery systems for therapeutic applications.
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Nanopartículas , Ácidos Nucleicos , Ácidos Nucleicos/uso terapéutico , Ácidos Nucleicos/química , Proteínas , Sistemas de Liberación de Medicamentos , Nanopartículas/químicaRESUMEN
Eukaryotic retroelements are generally divided into two classes: long terminal repeat (LTR) retrotransposons and non-LTR retrotransposons. A third class of eukaryotic retroelement, the Penelope-like elements (PLEs), has been well-characterized bioinformatically, but relatively little is known about the transposition mechanism of these elements. PLEs share some features with the R2 retrotransposon from Bombyx mori, which uses a target-primed reverse transcription (TPRT) mechanism, but their distinct phylogeny suggests PLEs may utilize a novel mechanism of mobilization. Using protein purified from E. coli, we report unique in vitro properties of a PLE from the green anole (Anolis carolinensis), revealing mechanistic aspects not shared by other retrotransposons. We found that reverse transcription is initiated at two adjacent sites within the transposon RNA that is not homologous to the cleaved DNA, a feature that is reflected in the genomic "tail" signature shared between and unique to PLEs. Our results for the first active PLE in vitro provide a starting point for understanding PLE mobilization and biology.
RESUMEN
Patients who have undergone hematopoietic stem cell transplantation (HSCT) in childhood have a higher risk of diastolic heart failure (HF). The rate of progression of diastolic dysfunction in aging pediatric patients is unknown and is more difficult to assess in young patients secondary to changes in diastolic indices as they grow. HSCT recipients at our center were previously found to have decline in diastolic function indices at 1 year after HSCT. This study provides follow-up of this cohort, using age-normalized z-scores to assess whether the decline in diastolic function noted at 1-year post-HSCT persists, worsens, or improves over time. Patients age <21 years who underwent HSCT at Boston Children's Hospital/Dana-Farber Cancer Center between 2005 and 2008 with ≥3 surveillance echocardiograms, including 1 performed pre-HSCT, were included. Diastolic measures included mitral inflow (E/A ratio) and Doppler tissue imaging of left ventricular lateral wall (LV lateral e'), LV septal wall (septal e') and right ventricular free wall (RV e'). Systolic function was measured by LV ejection fraction (LVEF). Normalization by age was done using z-scores, and >±2 SD was defined as abnormal in linear modeling of diastolic dysfunction and systolic dysfunction over time. In a subset of patients with adequate post-HSCT images of the entire left atrium (LA), LA volume and LA strain analyses also were performed. The study cohort comprised 61 patients (41% female; median age at HSCT, 10.7 years; median follow-up, 7.4 years). Diastolic index z-scores declined by -.045/year for LV lateral e', -.06/year for LV septal e', and -.14/year for RV e' (P < .01). The E/A ratio z-score increased by .034/year (P = .028). Linear modeling demonstrated that LV lateral e' and LV septal e' would become abnormal at 25 and 20 years post-HSCT, respectively, whereas RV e' would become abnormal sooner, at 12.6 years. LVEF z-score declined by -.04/year (P < .01) and was estimated to become abnormal at 40 years post-HSCT. Exposure to total body irradiation (TBI) was associated with worsening diastolic indices, lower LVEF (P ≤ .002), and decreased LA reservoir strain (42.0% versus 45.0%; P = .016) and conduit strain (-31.5% versus -35.1%; P = .029), although there was significant overlap between TBI and anthracycline exposure. Treatment with anthracyclines even at low doses (median, 150 mg/m2) was associated with declining LVEF but not with changes in diastolic indices. Long-term survivors of childhood HSCT exhibit declines in both LV and RV diastolic function indices. These results inform the rate of progression of LV and RV diastolic dysfunction indices over time in long-term survivors of pediatric HSCT. A significant association was observed between TBI and diastolic dysfunction and a decline in LVEF. Treatment with anthracyclines even at low doses was associated with a mild decline in LVEF. Our results can inform a lifespan perspective on disease management in this population, encourage clinicians and patients to be vigilant in following guideline-directed surveillance echocardiography, and inform anticipatory responses by clinicians as patients transition from pediatric care to adult care.
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Atrios Cardíacos , Trasplante de Células Madre Hematopoyéticas , Adulto , Humanos , Niño , Femenino , Adulto Joven , Masculino , Estudios de Seguimiento , Sobrevivientes , Trasplante de Células Madre Hematopoyéticas/efectos adversos , AntraciclinasRESUMEN
PURPOSE: This study examined the body composition, nutritional knowledge, behaviors, attitudes, and educational needs of senior schoolboy rugby players in Ireland. METHODS: Participants included 203 male rugby players age 15-18 yr competing at Senior School's Cup level in Leinster, Ireland. Estimation of body composition included measurement of height, weight, and percentage body fat (PBF; using bioelectrical impedance analysis, Tanita BC-418). Nutritional knowledge, behaviors, attitudes, and education needs were assessed by questionnaire. RESULTS: The range of PBF was 5.1-25.3%. Sixty-eight percent of the players in this study had a healthy PBF (10-20%), 32 (22%) were classified as underweight (<10% body fat), and 9.7% (n = 14) were overweight. Assessment of nutritional knowledge demonstrated poor knowledge of the foods required for refueling, appropriate use of sports drinks, and the role of protein in muscle formation. Alcohol consumption and dietary supplement use were reported by 87.7% and 64.5%, respectively. A perception that greater body size enhances sport performance did not predict dietary supplement use. Nutritional advice had been previously sought by 121 players from coaches (66.9%), magazines (42.1%), Web sites (38.8%), peers (35.5%), family (28.1%), sport organizations (16.5%), and health professionals (8.2%). Nutritional knowledge was no better in these players, nor did better nutritional knowledge correlate with positive dietary behaviors or attitudes. CONCLUSIONS: Most players had a healthy PBF. Despite a positive attitude toward nutrition, poor nutritional knowledge and dietary practices were observed in many players. Young athletes' nutritional knowledge and dietary practices may benefit from appropriate nutritional education.
Asunto(s)
Composición Corporal , Peso Corporal , Dieta , Fútbol Americano , Conocimientos, Actitudes y Práctica en Salud , Tejido Adiposo , Adolescente , Conducta del Adolescente , Consumo de Bebidas Alcohólicas , Rendimiento Atlético , Consejo , Suplementos Dietéticos/estadística & datos numéricos , Conducta Alimentaria , Conductas Relacionadas con la Salud , Educación en Salud , Humanos , Conducta en la Búsqueda de Información , Irlanda/epidemiología , Encuestas y CuestionariosRESUMEN
INTRODUCTION: Breastfeeding is associated with improved maternal and child outcomes. Women with a higher body mass index (BMI), who comprise about 50% of the population, are at increased risk of poorer breastfeeding practices and are a population who would benefit from breastfeeding. METHODS: This protocol is for a multi-centre, randomised controlled trial of perinatal breastfeeding support among primiparous women with a BMI >25 kg/m2, using a previously-tested, multi-component intervention. The primary outcome is any breastfeeding at 3 months. The intervention will support mothers and their partners and spans from late pregnancy to six weeks postpartum. Intervention components include group antenatal breastfeeding education, individual face-to-face education in the immediate postnatal period, professional support to six weeks' postpartum and weekly phone calls in the immediate postpartum period from an International Board Certified Lactation Consultant (IBCLC). The intervention will target attitudes towards breastfeeding, breastfeeding self-efficacy, and subjective norms around infant feeding with the aim to normalise the behaviour. RESULTS: We anticipate that the intervention will be well-accepted and feasible to carry out within four maternity units in the East of Ireland. Furthermore, essential formative qualitative work has been conducted to inform the intervention design and to ensure that it is contextually appropriate. CONCLUSION: The proposed intervention will be invaluable to policy-makers in providing insights into what specific interventions are effective in improving breastfeeding rates for women with a raised BMI.
RESUMEN
BACKGROUND: A common change that occurs with age in the central nervous system is an increase in microglial-associated inflammation. This is usually coupled with an increase in the concentration of the inflammatory cytokine interleukin-1beta (IL-1beta) in the hippocampus and an inhibition in long-term potentiation. OBJECTIVES: To assess the effects of a novel preparation of phospholipid nanoparticles incorporating phosphatidylglycerol, VP025, on inflammatory changes in hippocampus of aged and lipopolysaccharide (LPS)-treated rats. METHODS/RESULTS: We report that a possible initial target cell of the putative anti-inflammatory actions of VP025 may be macrophages, as VP025 is engulfed by, and has the capacity to alter the activity of, these cells. VP025 reversed the increase in IFN-gamma concentration in supernatant taken from peritoneal macrophages harvested from LPS-treated rats. In addition, markers of microglial activity, major histocompatibility complex class II (MHC II) mRNA expression, CD40 expression and IL-1beta concentration were increased, and CD200 expression was reduced, in the hippocampus of these rats. VP025 reversed changes in CD40, IL-1beta and CD200 in aged rats, and also restored long-term potentiation in aged and LPS-treated rats. CONCLUSIONS: We conclude that VP025 has the ability to modulate the activity of macrophage, microglia and neurons in response to stressors such as ageing and LPS treatment.
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Envejecimiento/fisiología , Antiinflamatorios/farmacología , Encefalitis/tratamiento farmacológico , Gliosis/tratamiento farmacológico , Microglía/efectos de los fármacos , Fosfatidilgliceroles/farmacología , Fosfolípidos/farmacología , Adulto , Animales , Antiinflamatorios/química , Encefalitis/inmunología , Encefalitis/fisiopatología , Gliosis/inducido químicamente , Gliosis/fisiopatología , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Hipocampo/fisiopatología , Humanos , Inmunomodulación/efectos de los fármacos , Inmunomodulación/fisiología , Interferón gamma/metabolismo , Interleucina-1beta/metabolismo , Potenciación a Largo Plazo/efectos de los fármacos , Potenciación a Largo Plazo/fisiología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , Trastornos de la Memoria/tratamiento farmacológico , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/fisiopatología , Microglía/fisiología , Nanopartículas/química , Vía Perforante/efectos de los fármacos , Vía Perforante/metabolismo , Vía Perforante/fisiopatología , Fagocitosis/efectos de los fármacos , Fagocitosis/fisiología , Fosfatidilgliceroles/química , Fosfolípidos/química , Ratas , Ratas Wistar , Células Tumorales Cultivadas , Factor de Necrosis Tumoral alfa/metabolismoAsunto(s)
Liderazgo , Partería/organización & administración , Rol de la Enfermera , Supervisión de Enfermería/organización & administración , Revisión por Expertos de la Atención de Salud/métodos , Gestión de la Calidad Total/organización & administración , Humanos , Relaciones Interprofesionales , Investigación en Administración de Enfermería , Medicina Estatal/organización & administración , Reino UnidoRESUMEN
BACKGROUND: Early onset neonatal sepsis (EOS, occurring in the first 72 hours of life) remains an important cause of illness and death among very low birth weight (VLBW) preterm infants. We previously reported a change in the distribution of pathogens associated with EOS from predominantly gram-positive to primarily gram-negative organisms. OBJECTIVE: To compare rates of EOS and pathogens associated with infection among VLBW infants born at centers of the National Institute of Child Health and Human Development (NICHD) Neonatal Research Network during 3 time periods: 1991-1993; 1998-2000; and 2002-2003. STUDY DESIGN: Prospectively collected data from the NICHD Neonatal Research Network VLBW registry were retrospectively reviewed. Rates of blood culture confirmed EOS, selected maternal and infant variables and pathogens associated with infection were compared between 2002-2003 and 2 previously published cohorts. RESULTS: During the past 13 years, overall rates of EOS have remained stable (15-19 per 1000 live births of infants 401-1500 g). More than one-half of early infections in the 2002-2003 cohort were caused by gram-negative organisms (53%), with Escherichia coli the most common organism (41%). Rates of group B streptococcal infections remain low (1.8 per 1000 live births). Between 1991-1993 and 1998-2000, there was a significant increase in rates of E. coli infections; but in 2002-2003, there was no significant change (7.0 per 1000 live births). Infants with EOS continue to be at significantly increased risk for death compared with uninfected infants. CONCLUSION: EOS remains an uncommon but important cause of morbidity and mortality among VLBW infants. Gram-negative organisms continue to be the predominant pathogens associated with EOS.
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Infecciones por Bacterias Gramnegativas , Enfermedades del Prematuro , Recién Nacido de muy Bajo Peso , Sepsis , Edad de Inicio , Femenino , Infecciones por Bacterias Gramnegativas/epidemiología , Infecciones por Bacterias Gramnegativas/microbiología , Infecciones por Bacterias Gramnegativas/mortalidad , Humanos , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/epidemiología , Enfermedades del Prematuro/microbiología , Enfermedades del Prematuro/mortalidad , Masculino , Sepsis/epidemiología , Sepsis/microbiología , Sepsis/mortalidadRESUMEN
Ipilimumab is a first-in-class immunological checkpoint blockade agent and monoclonal antibody against Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) that has demonstrated survival benefit and durable responses in patients with metastatic melanoma. To date, solid organ transplant recipients have been excluded from clinical trials with cancer immunotherapies on the basis of their concurrent treatment with immunosuppressive agents. We present the first case to our knowledge of a patient with advanced cutaneous melanoma receiving ipilimumab status post orthotopic liver transplantation with a partial response. Transaminitis was observed 4 months after administration of ipilimumab that resolved with close observation. No evidence of graft rejection has been observed to date. This case advocates for further investigation of the safety and efficacy of cancer immunotherapies in solid organ transplant recipients.
RESUMEN
Amyloid-beta (Abeta) peptides, the primary component of the amyloid plaques in Alzheimer's disease (AD), exert profound effects on neurons in vitro and negatively impact on neuronal function in vivo. One of the consequences of increased Abeta in the brain, either as a result of overexpression of the precursor amyloid precursor protein in transgenic mice, or injection into the brain is a decrease in one form of synaptic plasticity, long-term potentiation (LTP) in the hippocampus. Here we investigated the effect of infusion of Abeta for 28 days on LTP in dentate gyrus of rats and demonstrate that it was profoundly decreased compared with control-treated rats. We show that this effect is accompanied by increased activity of caspase 3, which is an indicator of cell stress. Significantly these changes were attenuated in animals which were pretreated with particles incorporating phosphatidylglycerol (VP025) and the evidence indicated that even when treatment was given 2 weeks after the start of the Abeta infusion, VP025 was capable of attenuating Abeta-induced changes. The evidence suggests that activation of caspase 3 was mediated by an Abeta-induced increase in sphingomyelinase, with the subsequent production of ceramide which is known to have a detrimental effect on neuronal function.
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Péptidos beta-Amiloides/administración & dosificación , Caspasa 3/efectos de los fármacos , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Péptidos beta-Amiloides/metabolismo , Animales , Caspasa 3/metabolismo , Estimulación Eléctrica , Hipocampo/fisiología , Potenciación a Largo Plazo/fisiología , Masculino , Ratas , Ratas WistarAsunto(s)
Anemia Ferropénica/dietoterapia , Educación del Paciente como Asunto , Administración Oral , Adolescente , Anemia Ferropénica/tratamiento farmacológico , Anemia Ferropénica/etiología , Modas Dietéticas , Suplementos Dietéticos , Femenino , Humanos , Hierro/uso terapéutico , Menstruación , Oligoelementos/uso terapéuticoRESUMEN
BACKGROUND: Whole-body hypothermia reduced the frequency of death or moderate/severe disabilities in neonates with hypoxic-ischemic encephalopathy in a randomized, controlled multicenter trial. OBJECTIVE: Our goal was to evaluate outcomes of safety and effectiveness of hypothermia in infants up to 18 to 22 months of age. DESIGN/METHODS: A priori outcomes were evaluated between hypothermia (n = 102) and control (n = 106) groups. RESULTS: Encephalopathy attributable to causes other than hypoxia-ischemia at birth was not noted. Inotropic support (hypothermia, 59% of infants; control, 56% of infants) was similar during the 72-hour study intervention period in both groups. Need for blood transfusions (hypothermia, 24%; control, 24%), platelet transfusions (hypothermia, 20%; control, 12%), and volume expanders (hypothermia, 54%; control, 49%) was similar in the 2 groups. Among infants with persistent pulmonary hypertension (hypothermia, 25%; control, 22%), nitric-oxide use (hypothermia, 68%; control, 57%) and placement on extracorporeal membrane oxygenation (hypothermia, 4%; control, 9%) was similar between the 2 groups. Non-central nervous system organ dysfunctions occurred with similar frequency in the hypothermia (74%) and control (73%) groups. Rehospitalization occurred among 27% of the infants in the hypothermia group and 42% of infants in the control group. At 18 months, the hypothermia group had 24 deaths, 19 severe disabilities, and 2 moderate disabilities, whereas the control group had 38 deaths, 25 severe disabilities, and 1 moderate disability. Growth parameters were similar between survivors. No adverse outcomes were noted among infants receiving hypothermia with transient reduction of temperature below a target of 33.5 degrees C at initiation of cooling. There was a trend in reduction of frequency of all outcomes in the hypothermia group compared with the control group in both moderate and severe encephalopathy categories. CONCLUSIONS: Although not powered to test these secondary outcomes, whole-body hypothermia in infants with encephalopathy was safe and was associated with a consistent trend for decreasing frequency of each of the components of disability.
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Temperatura Corporal/fisiología , Hipotermia Inducida/métodos , Hipoxia-Isquemia Encefálica/terapia , Evaluación de la Discapacidad , Estudios de Seguimiento , Humanos , Hipoxia-Isquemia Encefálica/mortalidad , Hipoxia-Isquemia Encefálica/fisiopatología , Lactante , Recién Nacido , Índice de Severidad de la Enfermedad , Tasa de Supervivencia/tendencias , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND: Erectile dysfunction (ED) may be one manifestation of a generalized vascular disorder characterized by endothelial dysfunction. Statin drugs may improve endothelial function, even before altering the lipid profile. OBJECTIVE: We sought to determine whether the addition of a statin with sildenafil would improve ED in men who initially responded poorly to sildenafil. METHODS: Men with moderate-to-severe ED despite an adequate sildenafil trial were enrolled in this randomized, double-blind, placebo-controlled pilot study. ED was defined using a validated self-administered questionnaire as a score of Asunto(s)
Anticolesterolemiantes/administración & dosificación
, Disfunción Eréctil/tratamiento farmacológico
, Ácidos Heptanoicos/administración & dosificación
, Erección Peniana/efectos de los fármacos
, Piperazinas/administración & dosificación
, Pirroles/administración & dosificación
, Adulto
, Anciano
, Atorvastatina
, LDL-Colesterol/metabolismo
, Relación Dosis-Respuesta a Droga
, Método Doble Ciego
, Quimioterapia Combinada
, Humanos
, Masculino
, Persona de Mediana Edad
, Proyectos Piloto
, Purinas
, Citrato de Sildenafil
, Sulfonas
, Resultado del Tratamiento
RESUMEN
Heart rate (HR), blood pressure (BP) and autonomic nervous system (ANS) activity vary diurnally, with a reduction in HR and BP, and a shift to vagal dominance during the dark phase. However, the cause of these changes, particularly the relative influence of sleep and circadian mechanisms, remains uncertain. The present study assessed the effect of sleep onset on HR, BP, high frequency (HF) component of heart rate variability (HRV), low frequency/high frequency (LF/HF) ratio and pre-ejection period (PEP). Sleep onset was dissociated from circadian influences by having subjects go to sleep at two different circadian phases, their normal time of sleep onset (normal sleep onset, NSO), and after a delay of 3 h (delayed sleep onset, DSO). The assumption was that changes caused by sleep onset would occur in association with sleep onset, irrespective of its timing, while circadian effects would have a consistent circadian phase and be independent of when sleep onset occurred. Thirteen and 17 subjects were run in the NSO and DSO conditions, respectively. Following a 1-h adaptation period, data collection began 2 h before subjects' normal time of sleep onset and continued until morning awakening. The lights were turned out after 2 h in the NSO condition and 5 h in the DSO condition. Subjects were required to maintain a supine position throughout the experimental sessions. The night-time decrease in HR was found to be due to both sleep onset and a circadian influence, with the circadian component being more prominent. In contrast, the fall in BP was largely due to a sleep onset effect. Increased vagal activity, as reflected in the HF component and a shift to vagal dominance in the LF/HF ratio, appeared to be primarily a function of the sleep system, while sympathetic activity, as assessed by PEP, reflected a circadian influence.