RESUMEN
RATIONALE: Early-onset adolescent depression is related to poor prognosis and a range of psychiatric and medical comorbidities later in life, making the identification of a priori risk factors for depression highly important. Increasingly, dysregulated levels of immune and neuroendocrine markers, such as C-reactive protein (CRP) and cortisol, have been demonstrated as both precursors to and consequences of depression. However, longitudinal research with adolescent populations is limited and demonstrates mixed immuno-endocrine-depression links. OBJECTIVE: This study explored the putative bidirectional relationship between salivary measures of cortisol (Cort) and CRP, including the novel Cort:CRP ratio and depression. METHODS: Participants from the randomized control trial 'Sleep and Education: learning New Skills Early' (SENSE) Study were 122 adolescents at risk for depression (73 females) aged 12-16 years (M = 12.71 years, SD = 1.01 years) assessed at baseline (T1), post-intervention (T2), and a two-year follow-up (T3). RESULTS: Logistic regression results demonstrated that adolescents with higher T1 Cort:CRPmorn ratio levels were two-fold more likely to develop a first-onset depressive disorder from T2 to T3 as compared to adolescents with lower Cort:CRPmorn ratio levels, ß = 0.73, t (36) = 2.15, p = .04, OR = 2.08. This effect was not moderated by treatment condition (ß = -1.38, t (13) = -1.33, p = .20) and did not change when controlling for known risk factors for depression, including sex, age, body-mass index, socio-economic status, T1 anxiety disorder, nor T1 sleep disturbance, anxiety, or depressive symptoms (ß = 0.91, t (31) = 2.14, p = .04). CONCLUSION: Results highlight potential immuno-endocrine dysregulation as an underlying risk factor for adolescent first-onset depression, and may inform the development of targeted, preventative biobehavioral treatment strategies for youth depression.
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Proteína C-Reactiva , Hidrocortisona , Adolescente , Ansiedad , Biomarcadores , Depresión/diagnóstico , Depresión/epidemiología , Femenino , HumanosRESUMEN
Inflammatory markers including C-Reactive Protein (CRP) are increasingly used within research and clinical settings. Yet, varying methodologies for cleaning immunoassay data with out of range (OOR) samples may alter characteristic levels of CRP, thereby obscuring interpretation and reliability. This study investigated the influence of eight immunoassay OOR data treatment techniques on salivary CRP (sCRP) samples from at-risk adolescents. Participants from the 'Sleep and Education: learning New Skills Early' (SENSE) Study were 86 adolescents at-risk for depression (50 female), aged 14.29 years (SD = 1.04). ANOVA results showed no statistically significant differences in average morning (F(7, 590) = 1.24, p = .28) and evening (F(7, 599)=1.29, p = .25) values produced by each OOR data cleaning technique. However, varying techniques produced differences in the magnitude of Pearson's correlations between consecutive saliva samples (r's between 0.27-0.78), and influenced the significance of a sCRP diurnal pattern; two techniques produced statistically higher morning than evening sCRP levels (t(85) = 2.70, p = .01 and t(85) = 2.67, p = .01), whereas six techniques failed to find statistical differences between morning and evening sCRP levels (p's >.05). Varying techniques also produced statistically divergent associations between sCRP and age and depressive symptoms. Results from this study provide evidence for the temporal stability of sCRP among adolescents, show winsorization as an effective OOR data management technique, and highlight the influence of methodological decisions in cleaning salivary biomarker data and the need for consistency within the field.
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Exactitud de los Datos , Inmunoensayo/métodos , Reproducibilidad de los Resultados , Adolescente , Factores de Edad , Biomarcadores/metabolismo , Proteína C-Reactiva/análisis , Proteína C-Reactiva/metabolismo , Depresión/metabolismo , Femenino , Humanos , Inflamación/metabolismo , Masculino , Proyectos de Investigación , Saliva/químicaRESUMEN
OBJECTIVE: To determine pregnancy outcome in women with atrial switch repair for transposition of the great arteries (TGA) and to compare follow up with a control group of childless women with the same repair. DESIGN: Retrospective cohort study. SETTING: Tertiary care medical centre. POPULATION: About 21 patients compared with 15 controls. METHODS: Review of records from joint cardiac-obstetric clinic 1993-2013. MAIN OUTCOME MEASURES: Occurrence of cardiovascular events: maternal death, heart failure, arrhythmia, thromboembolic events, worsening systemic ventricular function, worsening tricuspid valve regurgitation and newly detected baffle problems. RESULTS: There were 34 pregnancies in 21 women. Mean follow up was 100 months. No deaths or recurrence occurred. Events (few arrhythmias, thromboembolic events and baffle issues) were common in both groups: 13 (62%) patients and eight (53%) controls (P = 0.736). Worsening of ventricular function was similar in both groups: six (29%) patients and four (27%) controls (P = 0.899). Worsening tricuspid regurgitation was more common in patients [11 (52%)] than controls (0)] (P < 0.001). Labour was induced in 76% cases: 32% for cardiac deterioration, 37% to control timing of delivery, and 26% for intrauterine growth restriction. Delivery was vaginal in 84% cases. Median gestational age was 37 (30-40) weeks, median birthweight 2525 g (1460-3530). In all, 38% babies were premature and 38% were small-for-gestational-age. CONCLUSIONS: Cardiac events after atrial repair for TGA are equally common in pregnant women and non-pregnant controls, although worsening tricuspid regurgitation occurs more frequently in pregnancy. Induction of labour is to be expected but vaginal delivery is achievable in most cases. Infants are likely to be premature and small-for-gestational-age. TWEETABLE ABSTRACT: Pregnancy in atrial repair for TGA: cardiac events similar to controls, prematurity and small babies likely.
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Operación de Switch Arterial , Complicaciones Posoperatorias , Complicaciones del Embarazo/etiología , Transposición de los Grandes Vasos/cirugía , Adulto , Operación de Switch Arterial/métodos , Estudios de Casos y Controles , Femenino , Estudios de Seguimiento , Humanos , Recién Nacido , Recién Nacido Pequeño para la Edad Gestacional , Complicaciones Posoperatorias/epidemiología , Embarazo , Complicaciones del Embarazo/epidemiología , Estudios RetrospectivosRESUMEN
PURPOSE: A growing literature supports the association between insomnia and cardiovascular risk. Since only few studies have provided empirical evidence of hyper-activation of the cardiovascular system in insomniacs, the aim of the present study was to analyze cardiac autonomic responses in primary insomnia. METHODS: Impedance cardiography and heart rate variability (HRV) measures were assessed in 9 insomniacs and 9 good sleepers during a night of polysomnographic recording. RESULTS: Insomniacs were found to be characterized by a constant sympathetic hyper-activation which was maintained all night, as suggested by a faster pre-ejection period (PEP) compared to good sleepers. In addition, only insomniacs showed a strong reduction in heart rate in the transition from wake to sleep. Both groups exhibited a reduction in cardiac output and sympathovagal balance, i.e., reductions in low-frequency/high-frequency ratio and increases in high-frequency normalized units of HRV, across the night. In addition, in our sample, a high physiological sympathetic activation (fast PEP) at night was found to be directly associated with low quality of sleep. CONCLUSIONS: These preliminary findings suggest that a constant cardiac sympathetic hyper-activation throughout the night is a main feature of primary insomnia. Our evidences support the association between insomnia and increased risk for cardiovascular diseases.
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Trastornos del Inicio y del Mantenimiento del Sueño/fisiopatología , Sistema Nervioso Simpático/fisiopatología , Adulto , Cardiografía de Impedancia , Enfermedades Cardiovasculares/fisiopatología , Electrocardiografía , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Polisomnografía , Factores de Riesgo , Sueño/fisiología , Adulto JovenRESUMEN
The management of anticoagulation in pregnant women with mechanical heart valves is complex. The maternal and fetal outcomes of 32 pregnancies in 15 women on three different anticoagulation regimens were compared. Anticoagulation with low-molecular-weight heparin (n=4), warfarin (n=22) and combination therapy (n=6) resulted in adverse maternal events in four (100%), three (50%) and three (14%) women, and resulted in fetal losses in one (25%), 17(77%) and three (50%) pregnancies, respectively. Whereas the rate of fetal loss in the warfarin group was high, all women in the LMWH and half of those in the combination group had serious adverse maternal events, including valve thrombosis, maternal death and postpartum haemorrhage.
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Anticoagulantes/administración & dosificación , Anticoagulantes/efectos adversos , Prótesis Valvulares Cardíacas , Heparina de Bajo-Peso-Molecular/efectos adversos , Complicaciones Cardiovasculares del Embarazo/tratamiento farmacológico , Warfarina/efectos adversos , Adulto , Muerte Súbita/etiología , Quimioterapia Combinada , Femenino , Muerte Fetal/inducido químicamente , Heparina de Bajo-Peso-Molecular/administración & dosificación , Humanos , Hemorragia Posparto/inducido químicamente , Embarazo , Resultado del Embarazo , Estudios Retrospectivos , Factores de Riesgo , Trombosis/inducido químicamente , Warfarina/administración & dosificación , Adulto JovenRESUMEN
STUDY OBJECTIVES: To quantitatively assess autonomic cardiovascular control in normal young adults following exposure to repetitive acoustically-induced arousals from sleep. DESIGN: Respiration, R-R interval (RRI) and noninvasive measurements of continuous arterial blood pressure were monitored in subjects during the transition from relaxed wakefulness to stable Stage 2 sleep. These measurements were made under undisturbed conditions or conditions in which transient arousals were induced repetitively by acoustic stimulation. A mathematical model was used to partition the fluctuations in RRI into a component ("RSA") correlated with respiration and a component ("A representing baroreflex control of heart rate. The magnitudes and forms of each component before and after exposure to repetitive arousals were compared SETTING: Sleep disorders laboratory in a university setting. PATIENTS OR PARTICIPANTS: Ten healthy young adults (5 male, 5 female) with an average age of 20.4 +/- 2.0 y and mean body-mass index of 23.8 +/- 2.9 kg/m2. INTERVENTIONS: Each subject participated in multiple sleep studies consisting of 4 conditions with 2 nights in each condition. The first condition consisted of undisturbed sleep (control), while in the other 3 conditions, the subjects were aroused from sleep by repetitive auditory stimuli applied continuously over a duration of 50 minutes, with periodicities of 30 seconds, 1 minute, and 2 minutes of sleep. MEASUREMENTS AND RESULTS: Exposure to repetitive arousal (RA) did not alter mean heart rate or blood pressure. However, ABR and RSA gains estimated using the model, increased from the onset of Stage 1 sleep to the start of stable Stage 2 sleep under the control condition, but remained unchanged in all RA conditions. There were also significant increases in low-frequency oscillations of systolic blood pressure in the RA conditions versus no change in the control condition. CONCLUSIONS: Exposure to RA over durations approximating an hour produces cumulative effects on autonomic control that are subtle and can only be detected when advanced signal processing methods are employed. More specifically, the increases in ABR and RSA gains that accompany increasing sleep depth in normal sleep are prevented from occurring.
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Nivel de Alerta/fisiología , Sistema Nervioso Autónomo/fisiología , Frecuencia Cardíaca/fisiología , Mecánica Respiratoria/fisiología , Fases del Sueño/fisiología , Vigilia/fisiología , Estimulación Acústica/métodos , Adulto , Barorreflejo/fisiología , Presión Sanguínea/fisiología , Femenino , Humanos , Masculino , Modelos Biológicos , Polisomnografía , Valores de Referencia , Sueño REM/fisiologíaRESUMEN
The calibre of the upper airway is thought to be dependant upon its passive anatomy/collapsibility and the activation of pharyngeal dilator muscles. During awake periods, the more collapsible upper airway in obstructive sleep apnoea (OSA) increases the dilator muscle activity through a negative-pressure reflex. A direct correlation between the critical closing pressure (P(crit)), as a measure of anatomy/collapsability and electromyogram (EMG) activity of genioglossus EMG (GG-EMG) and tensor palatini EMG (TP-EMG), was hypothesised. The relationship between these indices and pharyngeal resistance (R(phar)) was also examined. The study involved eight males with a mean age of 48 (interquartile range 46-52) yrs with OSA, and an apnoea/hypopnoea index of 75 (65-101).hr(-1) on two nights breathing normally and on nasal continuous positive airway pressure (nCPAP). The P(crit )was measured during nonrapid eye movement sleep on nCPAP using brief, incremental reductions in mask pressure. GG-EMG and TP-EMG were measured breath-by-breath, awake, during sleep onset and on nCPAP. R(phar) was measured using airway pressures and flow. Wakeful GG-EMG, early sleep TP-EMG and the sleep decrement in TP-EMG were directly related to P(crit). Muscle activation was negatively correlated with R(phar) for TP-EMG awake and GG-EMG early in sleep. In conclusion these results confirm that dilator muscle activation is directly related to airway narrowing and reduces resistance across patients with obstructive sleep apnoea.
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Músculos Palatinos/fisiopatología , Músculos Respiratorios/fisiopatología , Síndromes de la Apnea del Sueño/fisiopatología , Resistencia de las Vías Respiratorias/fisiología , Índice de Masa Corporal , Presión de las Vías Aéreas Positiva Contínua , Electromiografía , Humanos , Masculino , Persona de Mediana Edad , Síndromes de la Apnea del Sueño/terapia , Estadísticas no ParamétricasRESUMEN
OBJECTIVES: To compare the cost-effectiveness of alternative management methods of first-trimester miscarriage. DESIGN: Economic evaluation conducted alongside a large randomised controlled trial (the MIST trial). SETTING: Early pregnancy assessment units of seven participating hospitals in southern England. SAMPLE: A total of 1200 women with a confirmed pregnancy of less than 13 weeks of gestation with a diagnosis of incomplete miscarriage or missed miscarriage. METHODS: Random allocation to expectant management, medical management or surgical management. Collection of health service and broader resource use data, unit costs for each resource item and clinical outcomes. MAIN OUTCOME MEASURES: Costs (pounds, 2001-02 prices) to the health service, social services, women, carers and wider society during the first 8 weeks postrandomisation. Cost-effectiveness estimates, expressed in terms of incremental cost per gynaecological infection prevented; cost-effectiveness acceptability curves presented at alternative willingness-to-pay thresholds for preventing gynaecological infection. RESULTS: There was no significant difference in the incidence of gynaecological infection between groups. The net societal cost per woman was estimated at 1086.20 pounds in the expectant group, 1410.40 pounds in the medical group and 1585.30 pounds in the surgical group. Expectant management had a 97.8% probability of being the most cost-effective management method at a willingness-to-pay threshold of 10,000 pounds for preventing one gynaecological infection, while medical management had a 2.2% probability of being the most cost-effective management method. Expectant management retained the highest probability of being the most cost-effective management method at all willingness-to-pay thresholds of less than 70,000 pounds for preventing one gynaecological infection. CONCLUSIONS: Expectant and medical management of first-trimester miscarriage possess significant economic advantages over traditional surgical management.
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Aborto Espontáneo/economía , Aborto Espontáneo/terapia , Análisis Costo-Beneficio , Inglaterra , Femenino , Costos de la Atención en Salud , Humanos , Embarazo , Primer Trimestre del Embarazo , Atención Prenatal/economía , Atención Prenatal/estadística & datos numéricosRESUMEN
OBJECTIVE: To ascertain whether a clinically important difference exists in the incidence of gynaecological infection between surgical management and expectant or medical management of miscarriage. DESIGN: Randomised controlled trial comparing medical and expectant management with surgical management of first trimester miscarriage. SETTING: Early pregnancy assessment units of seven hospitals in the United Kingdom. PARTICIPANTS: Women of less than 13 weeks' gestation, with a diagnosis of early fetal demise or incomplete miscarriage. INTERVENTIONS: Expectant management (no specific intervention); medical management (vaginal dose of misoprostol preceded, for women with early fetal demise, by oral mifepristone 24-48 hours earlier); surgical management (surgical evacuation). MAIN OUTCOME MEASURES: Confirmed gynaecological infection at 14 days and eight weeks; need for unplanned admission or surgical intervention. RESULTS: 1200 women were recruited: 399 to expectant management, 398 to medical management, and 403 to surgical management. No differences were found in the incidence of confirmed infection within 14 days between the expectant group (3%) and the surgical group (3%) (risk difference 0.2%, 95% confidence interval - 2.2% to 2.7%) or between the medical group (2%) and the surgical group (0.7%, - 1.6% to 3.1%). Compared with the surgical group, the number of unplanned hospital admissions was significantly higher in both the expectant group (risk difference - 41%, - 47% to - 36%) and the medical group (- 10%, - 15% to - 6%). Similarly, when compared with the surgical group, the number of women who had an unplanned surgical curettage was significantly higher in the expectant group (risk difference - 39%, - 44% to - 34%) and the medical group (- 30%, - 35% to - 25%). CONCLUSIONS: The incidence of gynaecological infection after surgical, expectant, and medical management of first trimester miscarriage is low (2-3%), and no evidence exists of a difference by the method of management. However, significantly more unplanned admissions and unplanned surgical curettage occurred after expectant management and medical management than after surgical management. TRIAL REGISTRATION NATIONAL RESEARCH REGISTER: N0467011677/N0467073587.
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Aborto Espontáneo/terapia , Complicaciones Infecciosas del Embarazo/terapia , Actividades Cotidianas , Dilatación y Legrado Uterino/estadística & datos numéricos , Femenino , Humanos , Hemorragia Posparto/etiología , Embarazo , Resultado del Embarazo , Primer Trimestre del Embarazo , Factores de Riesgo , Ausencia por EnfermedadRESUMEN
Blood pressure (BP) and heart rate (HR) are influenced by the sleep-wake cycle, with relatively abrupt falls occurring in association with sleep onset (SO). However, the pattern and rate of fall in BP and HR during SO and the processes that contribute to the fall in these variables have not been fully identified. Continuous BP and HR recordings were collected beginning 1 h before lights out (LO) until the end of the first non-rapid eye movement sleep period in 21 young, healthy participants maintained in a supine position. Five consecutive phases were defined: 1) the 30 min of wakefulness before LO; 2) LO to stage 1 sleep; 3) stage 1 to stage 2 sleep; 4) stage 2 sleep to the last microarousal before stable sleep; and 5) the first 30 min of undisturbed stable sleep. The data were analyzed on a beat-by-beat basis and reported as 2-min periods for phases 1 and 5 and 10% epochs for phases 2, 3, and 4 (as participants had variable time periods in these phases). The level of baroreflex (BR) activity was assessed by the sequence technique and an autoregressive multivariate model. Furthermore, during phases 3 and 4, the BP and HR responses to arousal from sleep were determined. There were substantial falls in BP and HR after LO before the initial onset of theta;-activity (phase 3) and again after the onset of stable sleep after the cessation of spontaneous arousals. During phases 3 and 4 when there were repeated arousals from sleep, the fall in both variables was retarded. Furthermore, both the rate and magnitude of the fall in BP were negatively associated with the number of arousals during phases 3 and 4. There was a small increase in the sensitivity of the BR and indirect evidence of a substantial fall in its set point.
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Nivel de Alerta/fisiología , Barorreflejo/fisiología , Presión Sanguínea/fisiología , Diagnóstico por Computador/métodos , Frecuencia Cardíaca/fisiología , Fases del Sueño/fisiología , Adaptación Fisiológica/fisiología , Adolescente , Adulto , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Polisomnografía/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Estadística como AsuntoRESUMEN
A previous study found that the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting. In this study, we examine (1) whether the cumulative effects of arousal can lead to significant changes in autonomic control and (2) how the frequency of arousals affect the magnitude of these effects. Ten healthy subjects were aroused from sleep every 30 seconds, 1 minute and 2 minutes of sleep for an hour. EEG, ABP, ECG and respiration were recorded, and the impulse responses of respiratory sinus arrhythmia (h(RSA)) and arterial baroreflex (h(RSA)) before and after 50 minutes of repetitive arousal were quantified by using a minimal closed loop cardiovascular model. We found that the low frequency baroreflex gain decreased after exposure to repetitive arousals of 2 minutes periodicity but remained unchanged in the control and other arousal conditions.
RESUMEN
We describe the management of an 83-year-old woman who presented with upper airway obstruction due to angioedema of the tongue. Following definitive airway management, investigation showed a diagnosis of acquired C1 esterase inhibitor deficiency (acquired angioedema) that was considered to be subsequent to haematological malignancy. Resolution of the macroglossia followed treatment with C1 esterase inhibitor concentrate, but the patient failed to wean from ventilatory support and died in the Intensive Care Unit. This case report highlights the potential for acquired angioedema to cause upper airway obstruction. The various treatment modalities for acquired C1 esterase inhibitor deficiency are summarized.
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Obstrucción de las Vías Aéreas/etiología , Angioedema/complicaciones , Proteínas Inactivadoras del Complemento 1/deficiencia , Macroglosia/complicaciones , Anciano , Anciano de 80 o más Años , Angioedema/etiología , Proteínas Inactivadoras del Complemento 1/uso terapéutico , Resultado Fatal , Femenino , Humanos , Trastornos Linfoproliferativos/complicaciones , Macroglosia/tratamiento farmacológico , Macroglosia/enzimologíaRESUMEN
The sensitivity and specificity of four self-report measures of disordered sleep - the Sleep Impairment Index (SII), the Sleep Disorders Questionnaire (SDQ), the Dysfunctional Beliefs and Attitudes About Sleep Scale (DBAS) and the Sleep-Wake Activity Inventory (SWAI) - were compared in subjects with insomnia and normal sleep. Nineteen young adult subjects met DSM-IV criteria for primary insomnia and another 19 were normal control subjects. Discriminatory characteristics of each measure were assessed using receiver operator characteristic curve analyses. Discriminatory power was maximised for each measure to produce cut-scores applicable for identification of individuals with insomnia. The DBAS, SII and SDQ psychiatric DIMS subscale were found to correlate, and discriminated well between the two groups. The SWAI nocturnal sleep subscale was not found to be an accurate discriminator. The results suggest differences in the measures in their ability to detect insomnia, and offer guidelines as to the optimal use of test scores to identify young adults suspected of insomnia.
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Trastornos del Inicio y del Mantenimiento del Sueño/diagnóstico , Adulto , Actitud Frente a la Salud , Trastorno Depresivo/diagnóstico , Trastorno Depresivo/psicología , Electroencefalografía , Electrooculografía , Femenino , Humanos , Masculino , Registros Médicos , Escalas de Valoración Psiquiátrica , Curva ROC , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Trastornos del Inicio y del Mantenimiento del Sueño/etiología , Encuestas y CuestionariosRESUMEN
Arousal from sleep is associated with elevated cardiac and respiratory activity. It is unclear whether this occurs because of homeostatic mechanisms or a reflex activation response associated with arousal. Cardiorespiratory activity was measured during spontaneous arousals from sleep in subjects breathing passively on a ventilator. Under such conditions, homeostatic mechanisms are eliminated. Ventilation, end-tidal PCO2, mask pressure, diaphragmatic electromyograph, heart rate, and blood pressure were measured in four normal subjects under two conditions: assisted ventilation and a normal ventilation control condition. In the control condition, there was a normal, sleep-related fall in ventilation and rise in end-tidal PCO2. Subsequently, at an arousal, there was an increase in respiratory and cardiac activity. In the ventilator condition, a vigorous cardiorespiratory response to a spontaneous arousal from sleep remained. These results indicate that sleep-related respiratory stimuli are not necessary for the occurrence of elevated cardiorespiratory activity at an arousal from sleep and are consistent with the hypothesis that such activity is at least in part due to a reflex activation response.
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Nivel de Alerta/fisiología , Corazón/fisiología , Mecánica Respiratoria/fisiología , Sueño/fisiología , Adulto , Presión Sanguínea/fisiología , Dióxido de Carbono/sangre , Electroencefalografía , Electromiografía , Electrooculografía , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Respiración Artificial , Pruebas de Función Respiratoria , Vigilia/fisiologíaRESUMEN
STUDY OBJECTIVES: To determine whether the cortical response to mid-inspiratory occlusions can be used as a model of the cortical response to obstructive events during sleep; and to determine whether the vertex sharp wave (VSW) and K-complex are exclusive contributors to the N350 and N550 components respectively of the stage 2 sleep event-related potential. DESIGN: Two types of respiratory stimuli were used to elicit evoked potential responses during stage 2 NREM sleep. These were mid-inspiratory occlusions and complete breath obstructions. Trials were grouped according to the type of phasic response elicited; isolated K-complex (KC), VSW associated with a K-complex (VSW/KC), isolated VSW, and no evoked response (other). Evoked responses were averaged separately within these categories. SETTING: Data were collected in the University of Melbourne Sleep Laboratory. PARTICIPANTS: Six young healthy male adults. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Data were recorded from 29 scalp sites referenced to linked ears. Mask pressure (Pm) and airflow were also recorded. Intra-thoracic pressure, as indicated by Pm, reached a more negative level following complete obstructions than brief occlusions. However, both types of respiratory stimuli elicited the two late latency components. Although latency varied across the two respiratory conditions in a manner consistent with the intra-thoracic pressure rise time differences, the elicitation characteristics and topographic distribution of these components did not vary across the two types of stimuli. In addition, an N350 was only present in the average for those categories that included VSWs, while an N550 was only present in those categories that contained K-complexes. CONCLUSIONS: Mid-inspiratory occlusions can be used as a model of obstructive events. VSWs contribute exclusively to the N350 component, while K-complexes contribute exclusively to the N550 component.
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Potenciales Evocados/fisiología , Apnea Obstructiva del Sueño/diagnóstico , Sueño REM/fisiología , Adulto , Electroencefalografía , Humanos , Masculino , Índice de Severidad de la Enfermedad , Fases del Sueño/fisiología , Factores de TiempoRESUMEN
A prospective panel study was conducted to measure seasonality of mood in a random community sample in Melbourne, Australia (N = 245). Based on research into the structure of human mood, it was predicted that a lowering of mood in winter relative to summer would be observed in positive affect (PA) and behavioral engagement (BE), but not negative affect (NA). These variables were measured across summer and winter for 3 years. Consistent with the majority of research in the Northern Hemisphere, analyses on the entire sample found evidence of a small prospective season effect on the BE scale (explaining 2.1% of variance in BE scores). Also, as expected, no season effect was seen on the NA scale. In the entire sample, the season effect was not significant for PA, but joint factor analysis of the BE, PA, and NA scales confirmed that the season effect seen in the BE scale was largely due to items that were pure measures of PA. Winter pattern seasonality was both reliable across measures and significantly more marked among the subgroup of respondents who self-identified winter pattern of mood on the Seasonal Pattern Assessment Questionnaire.
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Afecto , Estaciones del Año , Conducta , Fenómenos Cronobiológicos , Femenino , Humanos , Estudios Longitudinales , Masculino , Estudios Prospectivos , Trastorno Afectivo Estacional/psicología , Encuestas y Cuestionarios , VictoriaRESUMEN
While there is a developing understanding of the influence of sleep on cardiovascular autonomic activity in humans, there remain unresolved issues. In particular, the effect of time within the sleep period, independent of sleep stage, has not been investigated. Further, the influence of sleep on central sympathetic nervous system (SNS) activity is uncertain because results using the major method applicable to humans, the low frequency (LF) component of heart rate variability (HRV), have been contradictory, and because the method itself is open to criticism. Sleep and cardiac activity were measured in 14 young healthy subjects on three nights. Data was analysed in 2-min epochs. All epochs meeting specified criteria were identified, beginning 2 h before, until 7 h after, sleep onset. Epoch values were allocated to 30-min bins and during sleep were also classified into stage 2, slow wave sleep (SWS) and rapid eye movement (REM) sleep. The measures of cardiac activity were heart rate (HR), blood pressure (BP), high frequency (HF) and LF components of HRV and pre-ejection period (PEP). During non-rapid eye movement (NREM) sleep autonomic balance shifted from sympathetic to parasympathetic dominance, although this appeared to be more because of a shift in parasympathetic nervous system (PNS) activity. Autonomic balance during REM was in general similar to wakefulness. For BP and the HF and LF components the change occurred abruptly at sleep onset and was then constant over time within each stage of sleep, indicating that any change in autonomic balance over the sleep period is a consequence of the changing distribution of sleep stages. Two variables, HR and PEP, did show time effects reflecting a circadian influence over HR and perhaps time asleep affecting PEP. While both the LF component and PEP showed changes consistent with reduced sympathetic tone during sleep, their pattern of change over time differed.
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Presión Sanguínea/fisiología , Frecuencia Cardíaca/fisiología , Fases del Sueño/fisiología , Nervio Vago/fisiología , Adolescente , Adulto , Sistema Nervioso Autónomo/fisiología , Electroencefalografía , Electromiografía , Electrooculografía , Femenino , Humanos , Masculino , Posición Supina , Factores de Tiempo , Vigilia/fisiologíaRESUMEN
Arousals from sleep can be associated with increases in blood pressure (BP). However, it is uncertain whether this is due to a direct effect of arousals on BP, or is secondary to respiratory stimuli present at the time of the arousal. Cheyne-Stokes respiration (CSR) in patients with congestive heart failure (CHF) provides unique conditions that may allow these two possibilities to be distinguished. In CSR, the apnea-hyperpnea cycle can be dissociated from arousals because when CSR occurs during wakefulness, it does so in the absence of arousals, and when it occurs during sleep, arousals occur either at the termination of apnea (early arousals) or several breaths after the onset of hyperpnea (late arousals). We therefore measured BP during wakefulness and non-rapid eye movement (NREM) sleep in eight patients with CHF and CSR. During wakefulness, CSR was associated with wide fluctuations in systolic BP (mean +/- SD, 11.3 +/- 6.0 mm Hg) synchronous with the apnea-hyperpnea cycle, in the absence of arousals. Similar fluctuations in BP were observed during CSR with early arousals (13. 7 +/- 7.0 mm Hg) in NREM sleep. However, late arousals during CSR were associated with a small, but significant additional effect on systolic BP (14.2 +/- 7.1 mm Hg, p < 0.05). Furthermore, the degree of BP increase following arousals was directly related to the associated increase in ventilation (r = 0.70, p < 0.05). We conclude that BP fluctuations during CSR in patients with CHF are primarily related to oscillations in ventilation during the CSR cycle and can occur in the absence of arousals. Arousals augment these BP oscillations, but only when they occur late in hyperpnea.