Energy-environmental benefits and economic feasibility of anaerobic codigestion of Iberian pig slaughterhouse and tomato industry wastes in Extremadura (Spain).

Anaerobic digestion of Iberian pig slaughterhouse and tomato industry wastes, as well as codigestion operations from such residues, are reported to achieve 54-80% reduction in Chemical Oxygen Demand and 6-19 N m(3)/m(3) substrate methane production. Furthermore, 0.79-0.88 m(3)water/m(3) substrate is seen to be recovered after the above mentioned operations, which might be used as irrigation water, and 0.12-0.21 m(3)agricultural amendment/m(3) substrate with 91-98% moisture content. The present paper also reports on the economic feasibility of both an anaerobic codigestion plant operating with 60% slaughterhouse wastes/40% tomato industry wastes (optimal ratio obtained in previous laboratory-scaled experiments), and an anaerobic digestion plant for Iberian pig slaughterhouse waste. Payback times are reported as 14.86 and 3.73 years, respectively.

[Cardiac surgery in the elderly: comparison of medium-term clinical outcomes in octogenarians and the elderly from 75 to 79 years]. / Cirugía cardiaca en el anciano: comparación de resultados a medio plazo entre octogenarios y ancianos de 75 a 79 años.

INTRODUCTION AND OBJECTIVES: The age of patients undergoing cardiac surgery has increased in recent years. Our aims were to investigate the medium-term clinical outcomes of surgery in octogenarians and to compare them with outcomes in other elderly individuals of a less advanced age. METHODS: We investigated early mortality, the incidence of postoperative complications, medium-term survival and factors associated with these parameters in 589 consecutive elderly patients undergoing surgery: 140 were octogenarians aged 80-87 years (group I) while 449 were aged between 75 and 79 years (group II). RESULTS: The two groups were similar. There was no difference in mortality (10.0% in group I vs. 10.9% in group II) or in the incidence of postoperative complications (22% in group I vs. 30% in group II). Emergency surgery, combined surgery and pulmonary hypertension were all independent predictors of mortality and of major postoperative complications. The 5-year survival rate was 79% in group I and 65% in group II (P=.832) and the cardiac event-free survival rate was 75% in group I and 64% in group II (P=.959). Overall, 97% of patients in both groups were in functional class I or II. The additive EuroSCORE and preoperative atrial fibrillation were both associated with increased mortality during follow-up. Being an octogenarian was not a predictor (hazard ratio=0.78; 95% confidence interval, 0.51-1.21; P=.373). CONCLUSIONS: In selected octogenarians, cardiac surgery gives similar results to those obtained in other elderly individuals of a less advanced age. The medium-term survival rate and quality of life are good. Pulmonary hypertension, emergency surgery and combined surgery all increased risk in these patients.

Cirugía cardiaca en el anciano: comparación de resultados a medio plazo entre octogenarios y ancianos de 75 a 79 años / Cardiac Surgery in the Elderly: Comparison of Medium-Term Clinical Outcomes in Octogenarians and the Elderly From 75 to 79 Years

Introducción y objetivos. La edad de los pacientessometidos a cirugía cardiaca se ha incrementado en losúltimos años. Pretendemos conocer los resultados a medioplazo de la cirugía en octogenarios, comparándoloscon los de otros ancianos de menos edad.Métodos. Analizamos la mortalidad precoz, la incidenciade complicaciones postoperatorias, la supervivencia amedio plazo y los factores asociados a éstas de 589 ancianos consecutivos sometidos a cirugía: 140 octogenarios entre 80 y 87 años (grupo I) y 449 entre 75 y 70 años (grupo II).Resultados. Ambos grupos fueron homogéneos. Nohubo diferencias en la mortalidad (I, 10%; II, 10,9%) e incidencia de complicaciones postoperatorias (I, 22%; II,30%). La cirugía de emergencia, la combinada y la hipertensión pulmonar se asociaron de manera independiente a la mortalidad y al desarrollo de complicaciones mayores. La supervivencia a 5 años fue del 79% (I) y el 65% (II) (p = 0,832) y la supervivencia libre de evento cardiaco fue del 75% (I) y el 64% (II) respectivamente (p = 0,959). El 97% de los pacientes de ambos grupos se encontraban en clase funcional I-II. El EuroSCORE aditivo y la fibrilaciónauricular preoperatoria se asociaron a una mayormortalidad en el seguimiento. Ser octogenario no fuepredictor (hazard ratio = 0,78; intervalo de confianza del 95%, 0,51-1,21; p = 0,373).Conclusiones. La cirugía cardiaca en octogenarios seleccionados ofrece resultados similares a los de otros ancianos más jóvenes, con una buena supervivencia y calidad de vida a medio plazo. La hipertensión pulmonar, la cirugía de emergencia y la combinada conllevan un riesgo elevado en estos pacientes

Introduction and objectives. The age of patientsundergoing cardiac surgery has increased in recentyears. Our aims were to investigate the medium-termclinical outcomes of surgery in octogenarians and tocompare them with outcomes in other elderly individualsof a less advanced age.Methods. We investigated early mortality, the incidenceof postoperative complications, medium-term survival andfactors associated with these parameters in 589consecutive elderly patients undergoing surgery: 140were octogenarians aged 80-87 years (group I) while 449were aged between 75 and 79 years (group II).Results. The two groups were similar. There was nodifference in mortality (10.0% in group I vs. 10.9% in group II) or in the incidence of postoperative complications (22% in group I vs. 30% in group II). Emergency surgery, combined surgery and pulmonary hypertension were all independent predictors of mortality and of major postoperative complications. The 5-year survival rate was 79% in group I and 65% in group II (P=.832) and the cardiac event-free survival rate was 75% in group I and 64% in group II (P=.959). Overall, 97% of patients in both groups were in functional class I or II. The additive EuroSCORE and preoperative atrial fibrillation were both associated with increased mortality during follow-up. Being an octogenarian was not a predictor (hazard ratio=0.78; 95% confidence interval, 0.51—1.21; P=.373).Conclusions. In selected octogenarians, cardiacsurgery gives similar results to those obtained in otherelderly individuals of a less advanced age. The mediumterm survival rate and quality of life are good. Pulmonary hypertension, emergency surgery and combined surgery all increased risk in these patients

[Replacement therapy with protein C for meningococcal sepsis and fulminant purpura in pediatric patients]. / Tratamiento sustitutivo con proteína C en sepsis meningocócica y púrpura fulminante en pacientes pediátricos.

Disseminated intravascular coagulation as associated to sepsis contributes to the development of clinical multiple organ failure by extensive thrombosis in microcirculation vessels. This condition commonly manifests itself in severe meningococcal sepsis. On the skin, its clinical manifestation is extensive purpura with necrotic lesions that usually progress to serious distal ischemia and may call for amputation. A common denominator in these events regarding hemostasis is a depletion of so-called natural anticoagulant proteins, particularly protein C. According to clinical observations replacement therapy with human plasma-derived protein C concentrates has been associated with significantly improved clinical outcome in patients with meningococcal sepsis and fulminant purpura. This paper reports a case of acquired protein C deficiency in a girl with meningococcal sepsis, fulminant purpura, disseminated intravascular coagulation, and septic shock. Fresh plasma therapy was intended to increase consumption coagulopathy-depleted coagulation factors and to provide small amounts of protein C. The inability to restore protein C concentrations above 30%, and the presence of severe thrombopenia in the setting of disseminated intravascular coagulation led to the onset of replacement therapy using a human protein C concentrate (Ceprotin), which increased plasma protein C concentrations and contributed to revert the existing hypercoagulability status. Finally, evidence available in the literature regarding fulminant meningococcal sepsis management using human protein C concentrates and recombinant activated protein C is discussed.

Total sleep deprivation increases extracellular serotonin in the rat hippocampus.

Sleep deprivation exerts antidepressant effects after only one night of deprivation, demonstrating that a rapid antidepressant response is possible. In this report we tested the hypothesis that total sleep deprivation induces an increase in extracellular serotonin (5-HT) levels in the hippocampus, a structure that has been proposed repeatedly to play a role in the pathophysiology of depression. Sleep deprivation was performed using the disk-over-water method. Extracellular levels of 5-HT were determined in 3 h periods with microdialysis and measured by high performance liquid chromatography coupled with electrochemical detection. Sleep deprivation induced an increase in 5-HT levels during the sleep deprivation day. During an additional sleep recovery day, 5-HT remained elevated even though rats displayed normal amounts of sleep. Stimulus control rats, which had been allowed to sleep, did not experience a significant increased in 5-HT levels, though they were exposed to a stressful situation similar to slee-deprived rats. These results are consistent with a role of 5-HT in the antidepressant effects of sleep deprivation.

Performance of quantitative ultrasound in the discrimination of prevalent osteoporotic fractures in a bone metabolic unit.

There is a growing interest in ultrasound evaluation of bone status as an alternative to the measurement with dual X-ray absorptiometry (DXA), due to its low cost, portability, and nonionizing radiation. The aim of our study was to investigate the relation among DXA, QUS, clinical, anthropometric, and lifestyle factors, and to determine QUS cutoff values in order to discriminate fractures in patients referred to the Bone Metabolic Unit at an Endocrinology Service. We studied 300 patients (281 females and 19 males; age 58 +/- 11 years) referred for evaluation of osteoporosis. In all cases we determined basic anthropometric parameters, a clinical history including previous osteoporotic fractures and risk factors for osteoporosis, and QUS parameters in calcaneus (Hologic Sahara), and BMD in lumbar spine (LS) and femoral neck (FN), by DXA (Hologic QDR 1000). Using the WHO densitometric criteria, 37, 46.7, and 16.3% of our population were osteoporotic, osteopenic, and normal, respectively. A QUI T-score

Performance of COLIA1 polymorphism and bone turnover markers to identify postmenopausal women with prevalent vertebral fractures.

Some studies have suggested that bone turnover markers (BTM) and collagen type I alpha 1 gene (COLIA1) may be useful in the prediction of rates of future bone loss, and may therefore provide information about fracture risk. Our study aimed to examine the association of the COLIA1 genotype with the risk of vertebral fracture and to investigate the predictive value of this genetic factor in comparison with bone mineral density (BMD) and BTM, in ambulatory postmenopausal Spanish women. We determined the COLIA1 polymorphism by polymerase chain reaction, BMD by dual-energy X-ray absorptiometry and BTM in 43 postmenopausal women with prevalent vertebral fracture and a control group of 101 postmenopausal women without fracture. There was a significant overrepresentation of the 'T' allele in fractured women ( p = 0.029). BTM exhibited no differences between women with or without fractures or COLIA1 genotype groups. After adjusting for all other variables, the osteoporosis densitometric criteria variable was the most strongly associated with fracture (OR = 5 [1.8-13.3]) followed by COLIA1 (OR = 2.1 [1-4.3] per copy of the 'T' allele). Our study shows that COLIA1 is associated with prevalent vertebral fracture independently of bone mass, and the performance of this genetic factor to assess prevalent vertebral fracture is better than bone turnover markers.

Shock anafilático por hidatidosis en el postoperatorio inmediato / Anaphylactic shock of hydatidosis during recovery from surgery

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Relation between vitamin D insufficiency, bone density, and bone metabolism in healthy postmenopausal women.

Although only few postmenopausal women exhibit biochemical signs of hypovitaminosis D, vitamin D insufficiency has been shown to have adverse effects on bone metabolism and could be an important risk factor for osteoporosis and fracture. We determined serum levels of 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone (iPTH), bone turnover markers, dietary calcium intake, and bone mineral density (BMD; measured by dual X-ray absorptiometry) in 161 consecutive ambulatory women, healthy except for osteoporosis, referred to a bone metabolic unit. The prevalence of vitamin D insufficiency [25(OH)D < or = 15 ng/ml] was 39.1%. 25(OH)D was lower in the osteoporotic subjects (15.7 +/- 5.3 ng/ml vs. 21.8 +/- 9.7 ng/ml; p < 0.001). After controlling for all other variables, lumbar spine (LS) BMD was found to be significantly associated with 25(OH)D, body mass index (BMI), and years after menopause (YSM) (R2 = 0.253; p < 0.001). For femoral neck (FN), significant independent predictors of BMD were YSM, BMI, iPTH, and 25(OH)D (R2 = 0.368; p < 0.001). The probability of meeting osteoporosis densitometric criteria was higher in the vitamin D insufficiency group (odds ratio [OR], 4.17, 1.83-9.48) after adjusting by YSM, BMI, iPTH, and dietary calcium intake. Our study shows that vitamin D insufficiency in an otherwise healthy postmenopausal population is a common risk factor for osteoporosis associated with increased bone remodeling and low bone mass.

[Clinical results of double versus single mammary artery myocardiac revascularization: 15 years of follow-up]. / Resultados clínicos de la revascularización miocárdica con doble arteria mamaria frente a única: 15 años de seguimiento.

INTRODUCTION: Use of the left internal mammary artery to bypass the left anterior descending coronary artery reduces cardiac events and increases survival. However, there is some controversy as to the benefits of using both mammary arteries. OBJECTIVES: To assess the long-term outcome of the use of both mammary arteries in comparison with the use of only one. PATIENTS AND METHOD: A retrospective cohort study with a mean follow-up of 9.0 +/- 4.2 years was performed including 108 patients consecutively revascularized using both mammary arteries (II) and 108 patients randomly chosen in whom one mammary artery (I) was used for this purpose. RESULTS: Both groups were similar. There were no differences between the groups in operative morbidity or mortality. The survival at 10 years was similar (II: 84.61 +/- 4%; I: 85.18 +/- 3.8%), whereas recurrence of angina (II: 29.63 +/- 5.3%; I: 47.55 +/- 5.6%) (p = 0.012), the requirement for percutaneous angioplasty (II: 3.98 +/- 2%; I: 12.99 +/- 4.1%) (p = 0.009) and cardiologic events (II: 33.48 +/- 5.5%; I: 48.48 +/- 5.5%)(p = 0.022) were all lower in the group in which both mammary arteries were used. In the multivariate analysis, the use of both mammary arteries was an independent protective factor against angina recurrence (RR = 0.55), angioplasty (RR = 0.18) and cardiologic event (RR = 0.60). CONCLUSIONS: The use of both mammary arteries for revascularization does not increase operative morbidity. Since this procedure acts as an independent factor against angina recurrence, angioplasty and cardiologic event

The contribution of IGF-I to skeletal integrity in postmenopausal women.

OBJECTIVES: The pathogenic role of the decline in serum concentrations of IGF-I in postmenopausal osteoporosis is not fully elucidated. We investigated the associations among IGF-I, bone mineral density (BMD), ultrasound parameters and prevalence of vertebral fractures in postmenopausal women. DESIGN: A cross-sectional study. PATIENTS: One hundred and fifty-four ambulatory postmenopausal women (61 +/- 7 years) referred for osteoporosis screening. MEASUREMENTS: IGF-I was measured by radioimmunoassay and BMD using dual-energy X-ray absorptiometry. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) at calcaneus were measured by a quantitative ultrasound system. RESULTS: IGF-I was significantly lower in osteoporotic subjects and correlated positively with BMD, BUA and SOS. After adjusting for age, years since menopause and body mass index, IGF-I accounted for 8.5% of the variance at lumbar spine BMD, 4.6% at femoral neck and 7.1% at calcaneal BUA. BUA was associated with IGF-I independently of BMD. IGF-I was lower in women with vertebral fractures (91 +/- 39 microg/l vs. 114 +/- 44 microg/l; P = 0.003). The osteoporosis densitometric criteria (t-score < or = -2.5 SD) was the most strongly independent associated variable with prevalent vertebral fractures [odds ratio (OR): 3.3 (1.4-7.6)], followed by IGF-I levels below 75th percentile [OR: 3 (1-8.8)]. CONCLUSIONS: Our study shows that IGF-I is strongly associated with bone mineral density and reflects aspects of bone quality. The contribution of IGF-I to skeletal integrity in postmenopausal women is clinically relevant.

Utilidad de los marcadores de remodelado óseo / Utility of bone remodelling markers

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Evolución de la masa ósea en una mujer con hiperprolactinemia / Bone mass changes in a woman with increased prolactinemia

Presentamos el caso clínico de una mujer de 31 años de edad que fue diagnosticada de osteoporosis secundaria a hiperprolactinemia producida por un macroadenoma hipofisario resistente a tratamiento y la evolución de la masa ósea antes y después de tratamiento con terapia hormonal sustitutiva. (AU)

[Usefulness of bone densitometry in the evaluation of primary hyperparathyroidism]. / Utilidad de la densitometría ósea en la evaluación del hiperparatiroidismo primario.

BACKGROUND: In recent years, the clinical profile of primary hyperparathyroidism (PH) is predominantly characterized by mild or asymptomatic forms. In this context, the effects of the PH on bone metabolism reach a growing importance in the adoption of therapeutic decisions. PATIENTS AND METHODS: 116 patients with PH were studied, 95 women (25 premenopausal, 70 postmenopausal) and 21 males. In all cases parathyroidectomy criteria were evaluated. Bone mineral density (BMD) was determined in 71 patients in lumbar spine (LS) and femoral neck by dual-X-Ray absorptiometry (DXA) and the influence of this measurement in the decision of surgical treatment was analyzed. RESULTS: The patients with PH showed a significant reduction of BMD at all sites (p < 0.001) and 71.8% met osteoporosis densitometric criteria. The most frequent parathyroidectomy criteria was the presence of specific clinical manifestations (51.7%) followed by decrease of the BMD in LS (49.3%). The probability of meeting criteria for surgical treatment was significantly higher in patients in which BMD was measured (odds ratio: 3.09 [1.03-9.22]; p = 0.036). CONCLUSIONS: In its current presentation, PH presents a significant decrease of bone mass. The systematic performance of bone densitometry has a decisive influence in its appropriate management.

Influencia de la U.D.A. en la evolución del postoperatorio tras toracotomía / Influence of A.P.U. on the postoperative evolution after thoracotomy

Introducción: La incidencia de dolor moderado-severo en el postoperatorio continua siendo elevada a pesar de los conocimientos epidemiológicos, farmacológicos y técnicos actuales. El control de dicho dolor debe realizarse por el bienestar del paciente, por disminuir las complicaciones postoperatorias y por una ahorro en estancias hospitalarias y coste del proceso .Objetivos: Valorar la eficacia de una unidad de dolor agudo (U.D.A.) sobre el alivio del dolor tras toracotomía, valorando morbilidad y tiempo de estancia postoperatoria, y comparándola con los resultados del tratamiento analgésico consistente en AINE intravenoso programado + narcótico a demanda.Material y métodos: Se ha realizado un estudio re t rospectivo sobre 44 historias clínicas de pacientes sometidos a lobectomías o neumectomías en los años 1991-1992, 22 de los cuales recibieron como terapia analgésica metamizol magnésico intravenoso cada 6 horas + meperidina subcutánea (a demanda) y los otros 22 tratamiento específico pautado por la unidad de dolor agudo (U.D.A.) del Hospital Vi rgen de la Arrixaca de Murcia, consistente en narcóticos (morfina o fentanilo) más anestésicos locales (bupivacaína) vía epidural de forma continua asociados a AINE (metamizol magnésico) en perfusión intravenosa. Se registraron además de los datos demográficos, diagnóstico y tipo de intervención, duración de la intervención, narcóticos intraoperatorios, tiempo de estancia en reanimación, el tiempo de estancia postoperatoria en planta y las complicaciones postoperatorias reflejadas en la historia clínica (dolor, fieb re, disnea, atelectasias y exitus). El resto de complicaciones aparecidas se clasificaron como "otras". Se ha calculado el coste en UPAs (Unidad Ponderada de Asistencia), que representa el coste medio de un enfermo un día en planta .Estadísticamente, la comparación de grupos en cuanto a variables cuantitativas se ha realizado mediante un análisis de varianza complementado con contrastes de pares de medias mediante el test de la T-Student. La relación entre variables cualitativas se ha realizado mediante análisis de tablas de contingencia con el test de la 2 de Pearson complementado con el análisis de residuos, con el fin de detectar el sentido de la asociación o dependencia. La re l ación entre variables cuantitativas se ha establecido mediante análisis de correlación lineal entre pares de variables. Las diferencias las consideramos significativas para p<0,05.Resultados: Los resultados muestran unos datos demográficos y quirúrgicos similares. Dentro de las complicaciones se observa una mayor proporción de pacientes con dolor (p<0,001), atelectasias (p<0,001), exitus (p<0,01) y otras complicaciones (p<0,01) entre los pacientes que recibieron tratamiento analgésico convencional. El tiempo medio de estancia postoperatoria disminuyó significativamente en los pacientes tratados por la U.D.A., pasando de 13 + 1,82 a 9,64 + 2,04 días (p< 0,05). Al traducir estos datos de estancia a UPAs, también se aprecia una disminución similar del coste medio de las intervenciones (p< 0,05).Conclusiones: Como conclusión podemos afirmar que el tratamiento adecuado del dolor postoperatorio disminuye la morbilidad postoperatoria, el tiempo medio de estancia y el coste medio de las intervenciones (AU)

Personality disorders among medically refractory epileptic patients.

DSM-III-R personality disorders were assessed in 52 medically refractory epileptic patients. Twenty-one percent of patients met threshold criteria for an Axis II disorder. Dependent and avoidant personality disorders were the most common diagnoses. Epileptic aura was positively correlated with the presence of personality disorders. These results support previous studies that have demonstrated an increased rate of dependency and social isolation in epileptic patients. This increase may be related to disrupted psychosocial functioning as a consequence of having epilepsy, to disrupted neuronal function in central nervous system structures as a consequence of repeated epileptiform discharge or to some combination of the two.

In vivo microdialysis measures of extracellular serotonin in the rat hippocampus during sleep-wakefulness.

We investigated extracellular 5-hydroxytryptamine (5-HT) levels in rat hippocampus during different stages of the sleep-waking cycle using in vivo microdialysis. The extracellular 5-HT level was highest in active waking (AW) and, when compared to AW, 5-HT level was progressively lower in quiet waking (QW; 78%), quiet sleep (QS; 50%) and REM (which we termed active sleep (AS); 40%). Functional implications of AS related-decreased 5-HT in the hippocampus are discussed.

Methimazole-induced aplastic anemia in third exposure: successful treatment with recombinant human granulocyte colony-stimulating factor.

The major adverse reactions of antithyroid drugs are hematologic; aplastic anemia (AA) is one of the rarest and most severe complications. Use of recombinant human hemopoietic colony-stimulating factor was reported to be of benefit in patients who developed agranulocytosis, although there is still some doubt regarding the efficacy in AA. We present a case of a 58-year-old female patient with Graves' disease who developed AA in the third exposure to methimazole (MMI). The withdrawal of MMI and early treatment with 5 microg/kg per day recombinant human granulocyte colony-stimulating factor (G-CSF) for 9 days, allowed a favorable recovery of peripheral blood cell count. We conclude that the use of hemopoietic colony stimulating factors might be a suitable means to achieve the correction of severe thionamide-induced hematologic adverse reactions.

Effects of excitation of sensory pathways on the membrane potential of cat masseter motoneurons before and during cholinergically induced motor atonia.

Electrical stimulation of the nucleus pontis oralis during wakefulness enhances somatic reflex activity; identical stimuli during the motor atonia of active (rapid eye movement) sleep induces reflex suppression. This phenomenon, which is called reticular response-reversal, is based upon the generation of excitatory postsynaptic potential activity in motoneurons during wakefulness and inhibitory postsynaptic potential activity during the motor atonia of active sleep. In the present study, instead of utilizing artificial electrical stimulation to directly excite brainstem structures, we sought to examine the effects on motoneurons of activation of sensory pathways by exogenously applied stimuli (auditory) and by stimulation of a peripheral (sciatic) nerve. Accordingly, we examined the synaptic response of masseter motoneurons prior to and during cholinergically induced motor atonia in a pharmacological model of active sleep-specific motor atonia, the alpha-chloralose-anesthetized cat, to two different types of afferent input, one of which has been previously demonstrated to elicit excitatory motor responses during wakefulness. Following the pontine injection of carbachol, auditory stimuli (95 dB clicks) elicited a hyperpolarizing potential in masseter motoneurons. Similar responses were obtained upon stimulation of the sciatic nerve. Responses of this nature were never seen prior to the injection of carbachol. Thus, stimulation of two different afferent pathways (auditory and somatosensory) that produce excitatory motor responses during wakefulness instead, during motor atonia, results in the inhibition of masseter motoneurons. The switching of the net result of the synaptic response from one of potential motor excitation to primarily inhibition in response to the activation of sensory pathways was comparable to the phenomenon of reticular response-reversal. This is the first report to examine the synaptic mechanisms whereby exogenously or peripherally applied stimuli that elicit motor excitation during wakefulness instead elicit inhibitory motor responses during the motor atonia of active sleep. Thus, not only are motoneurons tonically inhibited during active sleep, but the selective elicitation of inhibitory motor responses indicates that this inhibition can be phasically increased in response to sensory stimuli, possibly in order to maintain the state of active sleep. The data provided the foundation for the hypothesis that, during naturally occurring active sleep, there is a change in the control of motor systems so that motor suppression occurs in response to stimuli that would otherwise, if present during other behavioral states, result in the facilitation of motor activity.