| human sleep/wake regulation. | the present paper gives a short overview on what is known about human sleep/wake regulation and focuses on two main component, the homeostatic component and the circadian. the homeostatic components increases sleep need exponentially as a function of prior wakefulness whereas the circadian component is a consequence of the 24-hour physiological rhythm facilitating sleep during the night and counteracting sleep during the day. normally, these components interact, in an additive way. this interact ... | 1997 | 9248514 |
| the hepatic perisinusoidal stellate cell. | hepatic stellate cell (also referred to as ito cell, fat-storing cell, perisinusoidal cell, lipocyte) is one of the sinusoid-constituent cells that play multiple roles in liver pathophysiology. although identification of the stellate cell had taken about 100 years because of the misconception caused by the discoverer von kupffer, wake made a great contribution to the "re" discovery of the cell in 1971. establishment of the isolation of hepatic non-parenchymal cells from rats by knook has made it ... | 1997 | 9302568 |
| chlamydia screening practices of primary-care providers -- wake county, north carolina, 1996. | genital chlamydial infection is the most commonly reported infectious disease in the united states, and the prevalence of chlamydia trachomatis genital infections in sexually active adolescents is 5%-15%, regardless of socioeconomic status. although chlamydial infections frequently are asymptomatic in women, untreated infections can cause extensive inflammation and scarring of the female reproductive tract. in addition, chlamydial infections may facilitate human immunodeficiency virus transmissi ... | 1997 | 9310215 |
| human time perception in temporal isolation: effects of illumination intensity. | living in isolation from time cues under relatively high and low light intensities for a total (on average) of 24 days, 18 subjects estimated the passage of time by "producing" short (10 to 120 seconds) and long (1h) intervals throughout the experiments. the 1h productions were independent of light intensity and highly positively correlated with the duration of wake times. the short-interval productions were markedly increased under high light intensity. in a subsample of 6 subjects, the interac ... | 1997 | 9360025 |
| complex effects of melatonin on human circadian rhythms in constant dim light. | in humans, the pineal hormone melatonin can phase shift a number of circadian rhythms (e.g., "fatigue", endogenous melatonin, core body temperature) together with the timing of prolactin secretion. it is uncertain, however, whether melatonin can fully entrain all human circadian rhythms. in this study, the authors investigated the effects of daily melatonin administration on sighted individuals kept in continuous very dim light. a total of 10 normal, healthy males were maintained in two separate ... | 1997 | 9376645 |
| melatonin and the circadian regulation of sleep initiation, consolidation, structure, and the sleep eeg. | the endogenous circadian rhythm of melatonin, driven by the suprachiasmatic nucleus, exhibits a close association with the endogenous circadian component of the sleep propensity rhythm and the endogenous circadian component of the variation in electroencephalogram (eeg) oscillations such as sleep spindles and slow waves. this association is maintained even when the sleep-wake cycle is desynchronized from the endogenous circadian rhythm of melatonin. administration of melatonin during the day inc ... | 1997 | 9406038 |
| sleep-disordered breathing and hypertension: past lessons, future directions. | that obstructive sleep apnea syndrome is an independent risk factor for the development of hypertension was established in the 1970s, and recent works on large samples have confirmed this fact. investigations of the mechanisms that may lead to the development of hypertension with sleep-disordered breathing will allow not only confirmation of the relationship but also creation of better treatment. there is a multigenic basis of blood pressure regulation, and genetic factors play a role in the dev ... | 1997 | 9406332 |
| design and construction of a long-term continuous video-eeg monitoring unit for simultaneous recording of multiple small animals. | in recent years several new rat models of human limbic/mesial temporal lobe epilepsy have been described [1,2,4-7,11,15-17]. unlike earlier models such as kindling in which the seizures are induced by an exogenous stimulus, these new models are characterized by seizures that occur spontaneously at random intervals. although the spontaneity of the seizures makes these models more like human epilepsy, documentation of these seizures by direct observation is highly inefficient, and sub-behavioral e ... | 1997 | 9438076 |
| [melatonin--a natural hypnotic?]. | the hypnogenic effects of melatonin are well documented in human pharmacological studies in normal volunteers after daytime parenteral and oral administration of pharmacological, supraphysiological and physiological doses. the findings after evening administration are not so unequivocal. from the clinical point of view, melatonin proved effective in double-blind, placebo-controlled trials in 2 types of sleep disorder: 1) as a chronobiotic in circadian rhythm sleep disorders such as jet lag-syndr ... | 1997 | 9441514 |
| hazard assessment of boric acid in toys. | boric acid (h3bo3) has been used in a wide variety of applications--medication, pesticides, and household products. reports of child poisoning by h3bo3 were common in the clinical literature before 1975. however, a decline in its use as a bacteriostatic agent coupled with increased regulatory control has almost eliminated poisonings by accidental ingestion. schedule i (part i, item 8) of the hazardous products act of canada, proclaimed in the late 1960s, followed in the wake of concerns about ac ... | 1997 | 9441917 |
| variation of electroencephalographic activity during non-rapid eye movement and rapid eye movement sleep with phase of circadian melatonin rhythm in humans. | 1. the circadian pacemaker regulates the timing, structure and consolidation of human sleep. the extent to which this pacemaker affects electroencephalographic (eeg) activity during sleep remains unclear. 2. to investigate this, a total of 1.22 million power spectra were computed from eegs recorded in seven men (total, 146 sleep episodes; 9 h 20 min each) who participated in a one-month-long protocol in which the sleep-wake cycle was desynchronized from the rhythm of plasma melatonin, which is d ... | 1997 | 9457658 |
| dynamics of the human eeg during prolonged wakefulness: evidence for frequency-specific circadian and homeostatic influences. | the electroencephalogram (eeg) of nine healthy individuals was recorded at half-hourly intervals during approximately 40 h of sustained wakefulness in a constant routine protocol. eeg power density in the 0.75-9.0 hz range exhibited a global increasing trend, and a local trough in the evening, centered approximately 6 h prior to the temperature minimum. the former could be attributed to a wake-dependent influence, and the latter to a circadian influence. power density in the 9.25-12.0 hz band sh ... | 1997 | 9469671 |
| an interpretation of the internal desynchronizations based on dynamics of the two-process model. | daan's two-process model is known to be one of the most powerful models, covering various situations from free-running to sleep deprivation. in this study, bifurcation properties of the model dynamics are clarified using a circle map. in addition, the two-process model is applied to simulate the two distinct patterns (the period-prolonged: i and the period-shortened: ii) of sleep-wake cycles during internal desynchronizations. we propose the novel interpretation that types i and ii could be rega ... | 1997 | 9470379 |
| [electrophysiologic study in a patient presenting with expanding cerebral lacunae]. | a 42-year-old man was affected with multiple cerebral lesions suggesting expanding lacunae. he had suffered for about 15 years of headaches and blurred vision. neurological examination showed a parinaud syndrome and a skew deviation. magnetic resonance imaging showed an enlargement of the third and lateral ventricles and multiple intraparenchymatous lesions with a signal similar to that of the cerebrospinal fluid. these lesions were located in the mesencephalon and right thalamic region. importa ... | 1997 | 9488973 |
| the effect of microgravity on testicular androgen secretion. | spaceflight causes a number of physiological changes in the human body. most would consider space travel to be a stressful event even for well-trained astronauts. should this be true, pituitary gonadotrophins (mainly lh) and testicular androgens, like testosterone (t), should decrease inflight in male astronauts. we therefore hypothesized that lowered testicular androgen levels might occur in men during spaceflight, due to stress-dependent lowered lh concentrations. | 1998 | 9491251 |
| seasonal and diurnal patterns of human illumination under natural conditions. | little is known about the natural pattern of seasonal and diurnal illumination to which normal people are exposed, especially in northern latitudes. in this study, ambient illumination of normal volunteers living at a latitude of 45 degrees 31' n was recorded with ambulatory photosensors worn for 5 to 6 days in winter and summer. results from 12 normal subjects (6 men, 6 women) aged 18 to 35 years were included in the analyses. the mean daily duration of time awake was similar in both seasons: 1 ... | 1998 | 9493715 |
| light and plasma melatonin rhythm in humans. | plasma melatonin rhythm in humans was investigated: its stability, relationship to the sleep-wake rhythm, and response to light. the so-called day-to-day variation of reference phases of plasma melatonin rhythm was within 1.4 h when blood was sampled at 1-hour intervals. therefore, a change in phase beyond this value is regarded as a phase shift of melatonin rhythm in individuals. plasma melatonin rhythm was spontaneously desynchronized from the sleep-wake rhythm and probably regulated by the co ... | 1997 | 9500670 |
| follicle-stimulating hormone is secreted more irregularly than luteinizing hormone in both humans and sheep. | recently introduced statistical tools capable of discerning differences between the pattern of luteinizing hormone (lh) secretion and that of follicle-stimulating hormone (fsh) could be valuable in understanding ovulation and menopause, and ultimately in making diagnostic decisions and treating infertility and polycystic ovary syndrome. we assessed the validity and scope of the hypothesis that fsh is secreted more irregularly than lh in ewes and fertile women. we compared secretory irregularity ... | 1998 | 9502773 |
| [effects of melatonin on circadian time keeping system]. | this paper is intended to provide an overview of a physiological role of melatonin (mlt) in sleep-wake regulation. in human mlt studies, mlt has significantly increased sleepiness and fatigue during the daytime but not at night, which indicates time-dependent sleep-promoting effect of mlt. op the other hand, mlt is known to have phase-shifting effect of biological clock. phase response curve (prc) for mlt administration was introduced in human studies. successful melatonin treatments for circadi ... | 1998 | 9503826 |
| [mutual connection between sleep-wake rhythm and other circadian rhythms]. | the desynchronaization between sleep-wakefulness rhythm and other biological rhythms such as rectal temperature rhythm and melatonin rhythm is the most unique characteristics for human circadian rhythms. based on the findings of desynchronaization, a multi-oscillator hypothesis has been advanced for the human circadian clock. three kind of the hypotheses such as wever, kronauer and two-process model were introduced in this article. according to the multi-oscillator hypothesis, one clock regulate ... | 1998 | 9503828 |
| [mathematical modeling of sleep-wake rhythms]. | so far, sleep researches have been improved by tight collaborations between behavioral and modeling studies. from the novel point of view, we developed the thermoregulatory model of sleep control, which reproduces the well-known features of human sleep-waking cycles. the biphasic daily pattern of sleepiness and the resulting behavior during sleep deprivation are mechanistically interpreted by reducing them into the behavior of the model elements. in addition, a physiological mechanism underlying ... | 1998 | 9503858 |
| aging, rhythms of physical performance, and adjustment to changes in the sleep-activity cycle. | shiftwork causes disturbances of the normal sleep-wake cycle and circadian rhythm. there is concern that aging workers have more problems than younger counterparts when the human body clock is disrupted. this review considers issues relating to aging, the circadian body clock, and adjustment to altered sleep-wake schedules. | 1997 | 9538354 |
| review of neural network applications in sleep research. | to find a better automated sleep-wake staging system for human analyses of numerous polygraphic records is an interesting challenge in sleep research. over the last few decades, many automated systems have been developed but none are universally applicable. improvements in computer technology coupled with artificial neural networks based systems (connectionist models) are responsible for new data processing approaches. despite extensive use of connectionist models in biological data processing, ... | 1998 | 9543484 |
| a parallelism between human body temperature and performance independent of the endogenous circadian pacemaker. | a battery of performance tests involving manual dexterity, serial search, and verbal reasoning was given about seven times per day to 2 healthy young male subjects (22 and 25 years of age) involved in separate forced desynchrony studies, each involving several months of temporal isolation. in these studies, the period lengths (denoted t) of the imposed day lengths (sleep/wake and light/dark cycles) were 25.8 and 26.0 h for the 2 subjects. for each subject, the endogenous circadian pacemaker (ecp ... | 1998 | 9554573 |
| circadian parameters as individual characteristics. | human circadian rhythms that are free running in temporal isolation can show an extreme variability of the sleep-wake cycle without the subject being aware of it. this is due mainly to a systematic adjustment of certain circadian time structures to the varying length of the "day": the perception of long time intervals in the range of 1 h and the intervals between meals have a strong positive correlation with the duration of wake time alpha, in contrast to the amount of hourly locomotor activity ... | 1998 | 9554574 |
| integrating the actions of melatonin on human physiology. | melatonin has a diverse range of physiological effects in humans. reported effects include modulation of the sleep-wake, thermoregulatory, cognitive, cardiovascular and immune systems. while integrating these broad-ranging effects is difficult when current paradigms are used, the diverse effects of melatonin on human physiology may be better understood by shifting our theoretical perspective. traditionally, research has treated melatonin as a classical hormone for which a defined effect in physi ... | 1998 | 9556095 |
| effects of exposure to alcohol in mother's milk on infant sleep. | to test the hypothesis that exposure to alcohol in breast milk affects infants' sleep and activity levels in the short term. | 1998 | 9565435 |
| citrobacter freundii empyema in a patient with occult pulmonary histoplasmosis. | the genus citrobacter includes three species of organisms that are uncommonly associated with human infection. when they are pathogenic, there are usually one or more associated respiratory, urinary, skin-soft tissue, and central nervous system infections and neonatal sepsis. these infections occur in the wake of significant systemic illness or complicate antibiotic usage. rarely, infection has been associated with active tuberculosis. the authors report a case of citrobacter freundii empyema in ... | 1998 | 9587088 |
| joint nasa-esa-dara study. part three: circadian rhythms and activity-rest cycle under different co2 concentrations. | during manned space missions, the actual concentration of carbon dioxide (co2) is frequently elevated to a degree that may affect human functioning and productivity. therefore, a ground-based international study was performed that tested various psychological and physiological functions under the condition of two different levels of co2. thus, a specific experiment aimed at the influence of enhanced co2-concentrations on the sleep-wake cycle and the circadian system. | 1998 | 9591622 |
| endocrinological and polysomnographic findings in kleine-levin syndrome: no evidence for hypothalamic and circadian dysfunction. | five subjects--four men, ages 17-28, and one woman, age 30--with kleine-levin syndrome were investigated during symptomatic (sp) and asymptomatic (asp) periods. investigations comprised medical history, mri, polysomnography, 24-hour hormone profile of human growth hormone, melatonin, tsh, cortisol and fsh (in the woman only) assessed every 2 hours, actimetry, and sleep logs. medical history confirmed presence of the three symptoms diagnostic of of typical kleine-levin syndrome: hypersomnia, exce ... | 1998 | 9595606 |
| genetic and environmental influences on prolactin secretion during wake and during sleep. | to delineate the contributions of genetic and environmental factors in the regulation of human prolactin (prl) secretion, the 24-h profile of plasma prl was obtained at 15-min intervals in 10 pairs of monozygotic and 10 pairs of dizygotic twins. sleep was monitored polygraphically. prl secretory rates were derived from plasma concentrations by deconvolution. diurnal (24-h) variations were quantified by a regression curve to define nadir, acrophase, and amplitude. pulses of prl secretion were ide ... | 1998 | 9612250 |
| disturbances in hormonal profiles of night workers during their usual sleep and work times. | in a previous study, the authors reported that the 24-h rhythms of pituitary and adrenal hormones--that is, thyrotropin (tsh), prolactin (prl), growth hormone, and cortisol--adapted only partially in a group of permanent night workers. however, the real impact of circadian rhythm alterations on the health and well-being of subjects is still unclear. in this study, the authors focus on an ergonomic field and address questions of adaptation of these hormones during the usual day sleep time (0700-1 ... | 1998 | 9615284 |
| influence of cedar essence on spontaneous activity and sleep of rats and human daytime nap. | we investigated whether exposure to the odor of extracted cedar essence (ce) has (i) an influence on spontaneous activity and sleep-wake states of rats and (ii) a sleep-promoting effect on human daytime nap after taking an ordinary night's sleep. in rats exposed to ce, spontaneous activities and amount of wake were significantly decreased, while the amount of non-rapid eye movement (nrem) sleep was significantly increased. in human daytime nap, nrem sleep stage 2 latency was significantly shorte ... | 1998 | 9628112 |
| evaluation of human activities and sleep-wake identification using wrist actigraphy. | the purpose of this study is to investigate the count-characteristics of wrist actigraphy in basic human activities and to discuss the agreement of sleep-wake identification between polysomnography (psg) and wrist actigraphy during nocturnal sleep. there was a distinct distribution of actigraphy counts over the studied activities. the evaluation of sleep-wake scoring using the wrist actigraphy agreed 96.9% with the polysomnographic scoring during nocturnal sleep. | 1998 | 9628125 |
| free-running of plasma melatonin rhythm prior to full manifestation of a non-24 hour sleep-wake syndrome. | a long-term observation of a sighted man who developed a non-24 h sleep-wake syndrome is reported. a partial entrainment was observed first, whereby the sleep-wake rhythm was entrained by the day-night alternation whereas the circadian rhythm in plasma melatonin was free-running. two years later, the sleep-wake rhythm of this subject started to free-run together with the melatonin rhythm. oral administration of melatonin for 2 weeks improved the entrainability of both rhythms but failed to entra ... | 1998 | 9628187 |
| transmission of multidrug-resistant human immunodeficiency virus--the wake-up call. | | 1998 | 9682050 |
| plasma melatonin rhythm is maintained in human african trypanosomiasis. | in human african trypanosomiasis (sleeping sickness), sleep and wake episodes are sporadically distributed throughout the day and the night. plasma melatonin, sleep-wakefulness and rectal temperature rhythms were studied in 9 congolese patients suffering from sleeping sickness compared to 6 healthy controls submitted to the same light/dark regime. the circadian distribution of the sleep-wake cycle was disturbed in relation to the severity of the disease. as controls, patients maintained a very d ... | 1998 | 9695940 |
| chronic insomnia and activity of the stress system: a preliminary study. | the aim of this study was to assess whether there is an association between chronic insomnia and the activity of the stress system. fifteen young adult insomniacs (<40 years) were studied. after an adaptation night, each subject was recorded in the sleep laboratory for three consecutive nights. during this period, 24-hour urine specimens were collected for measurements of urinary free cortisol (ufc), catecholamines, and growth hormone (gh). the 24-hour ufc levels were positively correlated with ... | 1998 | 9720852 |
| scoring of sleep and wakefulness by behavioral analysis from video recordings in rhesus monkeys: comparison with conventional eeg analysis. | extensive work on sleep-wake cycles in non-human primates has been carried out using conventional eeg scoring. in this study, simultaneous somnopolygrams and video recordings at 1 frame/s were performed on 6 adult rhesus monkeys (macaca mulatta) during a 24 h period. wakefulness, nrem sleep and rem sleep were scored by analysis of animal behavior from video data, using characteristic criteria for each state of vigilance. results were then compared with those of conventional eeg scoring. values o ... | 1998 | 9743278 |
| [are active neurons a better defense against aging in alzheimer's disease?]. | this article deals with the question whether metabolic activity of neurons interferes with their survival during brain aging and alzheimer's disease (ad). this 'use it or lose it' concept assumes that active neurons have a better chance to survive these conditions. we have monitored activity changes in human hypothalamic nuclei, that show differential survival patterns in aging and ad. the size of the golgi apparatus (ga) was measured in e.g. the nucleus basalis of meynert (nbm), that is severel ... | 1998 | 9746932 |
| [wake disorders. i. primary wake disorders]. | primary wake disorders encompass various conditions of excessive daytime sleepiness and/or increased nighttime sleep, of unknown origin beginning most often in adolescence and of chronic or recurrent natural history. the best known of these conditions is narcolepsy associating two major clinical features, irresistible episodes of sleep, sleep onset rem periods and an almost constant association with hla dr2-dq1. the prevalence of the condition is close to the one of multiple sclerosis but positi ... | 1998 | 9773032 |
| interrelations between sleep and the somatotropic axis. | in the human as in other mammals, growth hormone (gh) is secreted as a series of pulses. in normal young adults, a major secretory episode occurs shortly after sleep onset, in temporal association with the first period of slow-wave (sw) sleep. in men, approximately 70% of the daily gh output occurs during early sleep throughout adulthood. in women, the contribution of sleep-dependent gh release to the daily output is lower and more variable. studies involving shifts of the sleep-wake cycle have ... | 1998 | 9779515 |
| human perception of short and long time intervals: its correlation with body temperature and the duration of wake time. | time estimation was studied in seven human subjects during prolonged sojourn is isolation from time cues. they wore rectal temperature probes throughout the experiments, and during wakefulness recorded each time they thought one hour had passed. at the end of each of these subjective hours they produced a subjective 5 or 10 sec interval. the produced intervals on the 1-h task were not related to body temperature but were correlated with and proportional to the duration of waketime in all subject ... | 1998 | 9783235 |
| [interhemispheric relationships at various stages of the sleep-wake cycle in man]. | | 1998 | 9798321 |
| involvement of igf2 and h19 imprinting in choriocarcinoma development. | complete hydatidiform mole is an abnormal pregnancy characterized by grossly swollen villi in the absence of a fetus (kajii and ohama 1997, wake et al., 1978, jacobs et al., 1980). it is well known that this abnormal pregnancy product is androgenetic in origin. the entire genome of the molar conceptus is paternally derived. the majority of moles result from fertilization of an empty egg by haploid sperm. the paternally derived haploid set then duplicated without cytokinesis and restores diploidy ... | 1998 | 9833609 |
| postexposure prophylaxis after nonoccupational hiv exposure: clinical, ethical, and policy considerations. | in the wake of recent breakthroughs in antiviral therapies and centers for disease control and prevention (cdc) recommendations advocating occupational postexposure prophylaxis (pep), health care workers are increasingly receiving inquiries about pep following exposures to the human immunodeficiency virus (hiv) through sex and injection drug use. the probability of hiv transmission by certain sexual or injection drug exposures is of the same order of magnitude as percutaneous occupational exposu ... | 1998 | 9842953 |
| dampening of the cortisol response to handling at 3 months in human infants and its relation to sleep, circadian cortisol activity, and behavioral distress. | the decrease in responsiveness of the hypothalamic-pituitary-adrenocortical (hpa) system is marked over the first months of life. seventy-eight healthy infants (44 girls), 7 to 15 weeks old, were given a laboratory mock physical examination. salivary cortisol samples were collected pre- and postexamination and at home. behavioral state during the examination and home sleep/wake activity were measured. subjects younger than 11 weeks showed an increase in pre- to postexamination cortisol, while ol ... | 1998 | 9846236 |
| altered circadian melatonin secretion patterns in relation to sleep in patients with chronic sleep-wake rhythm disorders. | human well-being depends on the entrainment of endogenous circadian rhythms of biological functions and the sleep-wake rhythm. although the incidence of otherwise healthy subjects with chronically altered sleep-wake rhythms is rather low, the investigation of these patients provides new sights into circadian entrainment mechanisms. we therefore examined the circadian rhythm of circulating melatonin and the sleep-wake rhythm in five patients with chronic sleep-wake rhythm disorders and ten age-ma ... | 1998 | 9885989 |
| [heinrich von kleist and the true nature of man]. | in short-stories, novels and plays, the artist's interpretation of human nature may render the reader valuable insights into the basics of human behaviour. this article is a discussion of a short-story about a fictitious earthquake in chile, written in 1807 by heinrich von kleist (1777-1811). the writer shows how feelings of warmth, friendliness and solidarity come out when a catastrophe reduces the relative importance of man-made rules and regulations. but more sombre sides of human nature also ... | 1998 | 9914759 |
| reactive oligoarthritis in a patient with clostridium difficile pseudomembranous colitis. review of the literature. | a 57-year-old man developed oligoarthritis of the right sacroiliac joint, knee and elbow in the wake of clostridium difficile pseudomembranous colitis. he was hla b27-positive and had a history of reiter's syndrome. his joint manifestations resolved after a course of nonsteroidal antiinflammatory drug therapy and injection of the right knee with triamcinolone acetonide. clostridium difficile should be recognized as a rare cause of reactive arthritis. | 1998 | 9923050 |
| mu- and delta-opioid receptor densities in respiratory-related brainstem regions of neonatal swine. | the piglet displays similar postnatal development in respiration and sleep-wake behavior to the human. to shed light on the possible influence of opioid systems on these functions, this study assessed the density of mu- and delta-opioid receptors in brainstems of 2-3 and 5-7 (young), 14-17 (intermediate) and 20-21 (older) day-old piglets, using quantitative autoradiography. serial 10 microns sections from fresh-frozen brains were incubated with either mu-(125i-dago) or delta-(125i-dpdpe) opioid ... | 1999 | 9974154 |
| are we dependent upon coffee and caffeine? a review on human and animal data. | caffeine is the most widely used psychoactive substance and has been considered occasionally as a drug of abuse. the present paper reviews available data on caffeine dependence, tolerance, reinforcement and withdrawal. after sudden caffeine cessation, withdrawal symptoms develop in a small portion of the population but are moderate and transient. tolerance to caffeine-induced stimulation of locomotor activity has been shown in animals. in humans, tolerance to some subjective effects of caffeine ... | 1999 | 10073894 |
| [biologic rhythms: their changes in night-shift workers]. | environmental stress: environmental cycles, such as the light-dark cycle, provide information used by the biological clock in the hypothalamus to synchronize the biological systems and maintain the organism's internal cohesion. in persons whose work schedules include night hours (approximately 20% of the working population in france) the sleep-wake cycles are not in phase with these environmental cycles. biological rhythms: what effect does the conflicting information perceived by night-shift wo ... | 1999 | 10076605 |
| insulin-like growth factor-1 (igf-1)-induced inhibition of growth hormone secretion is associated with sleep suppression. | the hypothalamic growth hormone (gh)-releasing hormone (ghrh) promotes non-rapid eye movement sleep (nrems). insulin-like growth factor-1 (igf-1) acts as a negative feedback in the somatotropic axis inhibiting ghrh and stimulating somatostatin. to determine whether this feedback alters sleep, rats and rabbits were injected intracerebroventricularly (i.c.v.) with igf-1 (5.0 and 0.25 microgram, respectively) and the sleep-wake activity was studied. compared to baseline (i.c.v. injection of physiol ... | 1999 | 10082812 |
| refractory arthropathy after intravesical bacillus calmette-guérin therapy. usefulness of isoniazide. | arthritis associated with bacillus calmette-guérin immunotherapy usually responds dramatically to nonsteroidal antiinflammatory drug therapy. isoniazid is generally reserved for other complications such as granulomatous hepatitis. | 1999 | 10084171 |
| the fatigue experience for women with human immunodeficiency virus. | to examine fatigue as a symptom experienced by women with human immunodeficiency virus (hiv). | 1999 | 10102547 |
| modelling and exploring human sleep with event history analysis. | in this paper we propose the use of statistical models of event history analysis for investigating human sleep. these models provide appropriate tools for statistical evaluation when sleep data are recorded continuously over time or on a fine time grid, and are classified into sleep stages such as rem and nonrem as defined by rechtschaffen and kales (1968). in contrast to conventional statistical procedures, event history analysis makes full use of the information contained in sleep data, and ca ... | 1999 | 10188133 |
| effects of granulocyte colony-stimulating factor on night sleep in humans. | numerous animal studies suggest that cytokines such as interleukin-1beta (il-1beta) and tumor necrosis factor-alpha (tnf-alpha) mediate increased sleep amount and intensity observed during infection and are, moreover, involved in physiological sleep regulation. in humans the role of cytokines in sleep-wake regulation is largely unknown. in a single-blind, placebo-controlled study, we investigated the effects of granulocyte colony-stimulating factor (g-csf, 300 microgram sc) on the plasma levels ... | 1999 | 10198397 |
| age-related changes in sleep in the rat. | human sleep in old age is characterized by a number of changes, including reductions in sleep efficiency, amounts of visually scored slow-wave and rem sleep, and amplitude of the diurnal sleep/wake rhythm. in older rats, some, but not all, of these traits have been reported, including a decrease in the mean duration of sleep bouts, an increase in the number of sleep bouts, and a modest reduction of rem sleep. studies of the diurnal rhythm of total sleep have had varied results. there are, howeve ... | 1999 | 10201059 |
| periodic fatigue symptoms due to desynchronization in a patient with non-24-h sleep-wake syndrome. | a 43-year-old man complaining of recurrent fatigue symptoms and sleep disorders occurring periodically every 4 weeks was studied. using a wrist worn actigraphy and an ambulatory rectal temperature monitoring apparatus, his sleep-wake cycle and rectal temperature were measured continuously for 4 months, while diagnostic evaluation and therapeutic interventions were conducted. it was found that after he gave up an attempt to keep to a 24-h-day, a free-running sleep wake pattern appeared but his fa ... | 1998 | 10215008 |
| interhemispheric differences in awake and sleep human eeg: a comparison between non-linear and spectral measures. | interhemispheric differences in the eeg of nine healthy right-handed human subjects (c3 vs. c4 derivations) were investigated during resting wake with closed eyes (ce) and sleep stages i, ii, iii, iv and rem. the harmonic power spectral density within the eeg main spectral bands, the fractal (dr) and the correlation (d2) dimension as well as the largest lyapunov exponent (lambda1) of both hemispheres were compared. in addition, the relationships between non-linear and spectral measures were anal ... | 1999 | 10218905 |
| ultradian and circadian rhythms of sleep-wake and food-intake behavior during early infancy. | the early development of sleep-wake and food-intake rhythms in human infants is reviewed. the development of a 24 h day-night rhythm contains two observable developmental processes: the alterations in the periodic structure of behavior (decreased ultradian, increased circadian components) and the process of synchronization to external time (entrainment). the authors present the results of their studies involving 26 german children and compare them with previous investigations. in their research, ... | 1999 | 10219486 |
| cyclooxygenase-2: molecular biology, pharmacology, and neurobiology. | in the nervous system, prostanoids are well recognized as mediators in a variety of processes, including fever generation, modulation of the stress response, sleep/wake cycle, control of cerebral blood flow, and hyperalgesia. two isoforms of cyclooxygenase (cox), the enzyme that catalyzes the conversion of arachidonic acid to prostanoids, are now recognized: a constitutively expressed cox-1 and a highly regulated cox-2. new molecular and pharmacologic tools have provided a better understanding o ... | 1999 | 10223523 |
| leptin prevents respiratory depression in obesity. | human obesity leads to an increase in respiratory demands. as obesity becomes more pronounced some individuals are unable to compensate, leading to elevated arterial carbon dioxide levels (paco2), alveolar hypoventilation, and increased cardiorespiratory morbidity and mortality (pickwickian syndrome). the mechanisms that link obesity and hypoventilation are unknown, but thought to involve depression of central respiratory control mechanisms. here we report that obese c57bl/6j-lepob mice, which l ... | 1999 | 10228114 |
| the development of circadian rhythms in a human infant. | this study examines the ontogeny and interaction of circadian rhythms of sleep, wake, temperature, melatonin, and feeding in the human newborn, and the influence of photic and non-photic factors on the initiation of entrainment. | 1999 | 10341380 |
| nocturnal sleep and daytime sleepiness in normal subjects with hla-dqb1*0602. | narcolepsy, a neurological disorder characterized by excessive daytime sleepiness and abnormal rem sleep, is known to be tightly associated with the human leukocyte antigen (hla) dq allele dqb1*0602. in this study, we have explored the possibility that normal subjects carrying this hla allele (25% of the general population) could display subclinical rem sleep abnormalities and increased daytime sleepiness. data from 525 middle-aged adults enrolled in the wisconsin sleep cohort study were used fo ... | 1999 | 10341385 |
| circadian regulation of human sleep and age-related changes in its timing, consolidation and eeg characteristics. | the light-entrainable circadian pacemaker located in the suprachiasmatic nucleus of the hypothalamus regulates the timing and consolidation of sleep by generating a paradoxical rhythm of sleep propensity; the circadian drive for wakefulness peaks at the end of the day spent awake, ie close to the onset of melatonin secretion at 21.00-22.00 h and the circadian drive for sleep crests shortly before habitual waking-up time. with advancing age, ie after early adulthood, sleep consolidation declines, ... | 1999 | 10344586 |
| a circle map model of human circadian rhythms. | peculiar relationships between the sleep-wake cycle and temperature rhythm have been found during free-run situations, i.e. internal synchronization, internal desynchronization and phase trapping. the periods of both rhythms and the phase relationships between them could well characterize the above behavioral states. in this paper, firstly, our mathematical interpretations for them are proposed. according to these interpretations, a new circadian system model is developed. our model consists of ... | 1999 | 10354911 |
| [biologic rhythms. nyctemeral variation in man]. | corticotropic axis: the nycthemeral pattern of cortisol is a good marker of the circadian clock. cortisol levels fluctuate between a peak level, observed in the early hours of the morning, and a minimal level around midnight. this variability is considerably reduced or even abolished in cushing s syndrome. thyreotropic axis: the nycthemeral pattern of tsh secretion is dependent on both the circadian clock and sleep (which inhibits hormone secretion). the moment of the evening rise is a reliable ... | 1999 | 10360195 |
| genetic factors in human sleep disorders with special reference to norrie disease, prader-willi syndrome and moebius syndrome. | sleep-wake problems are common in specific inborn errors of metabolism and structure of the central nervous system. psychological factors, behavioural difficulties, metabolic disturbances, and widespread rather than focal damage to the nervous system are present in many of these diseases and all influence the sleep-wake cycle. however, a number of conditions cause relatively focal damage to the neuroanatomical substrate of sleeping and waking. these include fatal familial insomnia, with involvem ... | 1999 | 10389102 |
| human insulin gene insertion in mice. effects on the sleep-wake cycle? | recently, insulin synthesis and the presence of an insulin receptor have been demonstrated in the brain. intracerebroventricular infusion of insulin causes a selective increase in the amount of slow-wave sleep. in the present study, the sleep-wake cycle of transgenic mice, with or without habenular neuronal expression of the human insulin gene, was studied to investigate the possible role of brain insulin as a sleep modulator. slow-wave sleep duration was increased in those mice expressing human ... | 1999 | 10389109 |
| automated sleep staging systems in rats. | one of the major inconveniences encountered in sleep studies is the time consuming labor involved in equating visual analysis of physiological recordings (eeg, emg, eog, ...) to an appropriate state of vigilance. the explosion of computer technology is responsible for the emergence of several automated sleep-wake staging systems to supplement human analysis. conversely to human sleep analysis, rat sleep is characterized by the absence of consensus about numerous elements constituting the sleep-w ... | 1999 | 10389657 |
| the relationship between new variant creutzfeldt-jakob disease and bovine spongiform encephalopathy. | creutzfeldt-jakob disease (cjd) has been transmitted in the laboratory and also by iatrogenic accident. however, research has failed to find evidence that its most common form (sporadic cjd) is a natural infection and, in particular, that there is a causal link with scrapie. bovine spongiform encephalopathy (bse) probably resulted from scrapie infection in cattle food. in the wake of the bse epidemic, a novel clinico-pathological form of cjd has been recognized: new variant cjd (nvcjd). this pap ... | 1999 | 10394138 |
| effects of light on human circadian rhythms. | blind subjects with defective retinal processing provide a good model to study the effects of light (or absence of light) on the human circadian system. the circadian rhythms (melatonin, cortisol, timing of sleep/wake) of individuals with different degrees of light perception (n = 67) have been studied. blind subjects with some degree of light perception (lp) mainly have normally entrained circadian rhythms, whereas subjects with no conscious light perception (npl) are more likely to exhibit dis ... | 1999 | 10420432 |
| [familial fatal insomnia: a human prion disease which opens the door to a greater understanding of the thalamus]. | in 1986, lugaresi [1] described fatal familial insomnia (ffi), an inherited prion disease, characterised by untreatable insomnia and dysautonomia. the most severe neuropathological changes have been found in the mediodorsal (md) and anterior (a) thalamic nuclei. the data lead to think that the thalamus could play an important role in the wake-sleep cycle and other vegetative and endocrine circadian activities, specially md and a. | 1997 | 10420962 |
| determination of the d- and l-enantiomers of modafinil in human plasma utilizing liquid-liquid extraction and high-performance liquid chromatography. | modafinil, dl-2-[(diphenylmethyl)sulfinyl]acetamide (provigil), which is chiral at its sulfur atom, is a novel wake-promoting agent currently being developed as the racemate in the united states by cephalon, inc. in order to characterize the pharmacokinetic properties of each enantiomer, a stereospecific high-performance liquid chromatography (hplc) method has been developed for simultaneous determination of d- and l-modafinil in human plasma. the analytes are extracted from plasma into a mixtur ... | 1999 | 10437666 |
| forced desynchrony of circadian rhythms of body temperature and activity in rats. | the daily rhythm in body temperature is thought to be the result of the direct effects of activity and the effects of an endogenous circadian clock. forced desynchrony (fd) is a tool used in human circadian rhythm research to disentangle endogenous and activity-related effects on daily rhythms. in the present study, we applied an fd protocol to rats. we subjected 8 rats for 5 days to a 20 h forced activity cycle consisting of 10 h of forced wakefulness and 10 h for rest and sleep. the procedure ... | 1999 | 10442237 |
| is sleeping sickness a circadian disorder? the serotonergic hypothesis. | patients with human african trypanosomiasis (hat, sleeping sickness), due to the inoculation of trypanosoma brucei gambiense or rhodesiense by the tsetse fly, are "sleepy by day and restless by night." the first 24 h polysomnographic recording (electroencephalogram [eeg], electromyogram [emg], electrooculogram [eog]), showing a disappearance of the 24 h rhythmicity of sleep and wakefulness, was performed in 1988. thereafter, our team recorded 18 patients and 6 control volunteers at bed rest duri ... | 1999 | 10442241 |
| new findings in pharmacological effects induced by antihistamines: from pet studies to knock-out mice. | antihistamines are efficacious drugs to be used for the symptomatic relief of allergic diseases. the safety issue of antihistamines is of central importance because of their widespread use in current medical practice. to better understand the pharmacological effects of antihistamines on the central nervous system (cns), we used two kinds of new methods, positron emission tomography (pet) and gene targeting regarding on histamine h1 receptors. the histamine h1 receptor occupancy was examined in y ... | 1999 | 10444209 |
| linear demasking techniques are unreliable for estimating the circadian phase of ambulatory temperature data. | clinical investigators often use ambulatory temperature monitoring to assess the endogenous phase and amplitude of an individual's circadian pacemaker for diagnostic and research purposes. however, an individual's daily schedule includes changes in levels of activity, in posture, and in sleep-wake state, all of which are known to have masking or evoked effects on core body temperature (cbt) data. to compensate for or to correct these masking effects, many investigators have developed "demasking" ... | 1999 | 10447306 |
| reciprocal modulation of somatosensory evoked n20m primary response and high-frequency oscillations by interference stimulation. | we examined whether the inverse relation between somatic evoked n20m primary response and high-frequency oscillations during a wake-sleep cycle (hashimoto, i., mashiko, t., imada, t., somatic evoked high-frequency magnetic oscillations reflect activity of inhibitory interneurons in the human somatosensory cortex, electroenceph clin neurophysiol 1996;100:189-203) holds for interference stimulation. | 1999 | 10454280 |
| linear automatic detection of eye movements during the transition between wake and sleep. | slow eye movement (sem) are a sensitive indicator of lowered consciousness or drowsiness in man. a new computerized method for detection of sem was introduced. a linear regression analysis was applied in each moving window for approximation to the tangent line on the electro-oculogram curve. the results revealed that sem were more frequent and their duration was shorter at stage wake than at sleep stages 1 and 2. the method was practically suitable for objective detection and measurement of sem. | 1999 | 10459682 |
| familial advanced sleep-phase syndrome: a short-period circadian rhythm variant in humans. | biological circadian clocks oscillate with an approximately 24-hour period, are ubiquitous, and presumably confer a selective advantage by anticipating the transitions between day and night. the circadian rhythms of sleep, melatonin secretion and body core temperature are thought to be generated by the suprachiasmatic nucleus of the hypothalamus, the anatomic locus of the mammalian circadian clock. autosomal semi-dominant mutations in rodents with fast or slow biological clocks (that is, short o ... | 1999 | 10470086 |
| alleic variants of human melatonin 1a receptor: function and prevalence in subjects with circadian rhythm sleep disorders. | the human melatonin 1a (hmella) receptor gene was screened for mutations using genomic dna samples from patients with circadian rhythm sleep disorders and control subjects by single strand conformational polymorphism analysis (sscp). we found seven mutations, two of which predict amino acid changes r54w and a157v, respectively. the prevalence of the r54w variant and that of the a157v variant were several times more common in non-24-h sleep-wake syndrome subjects than among control subjects, alth ... | 1999 | 10471411 |
| reversal of the sleep/wake cycle disorder of sleeping sickness after trypanosomicide treatment. | to determine whether the circadian disruption of the sleep/wake cycle observed in sleeping sickness, human african trypanosomiasis (hat), can be reversed after trypanosomicide treatment, 10 congolese patients infected by trypanosoma brucei gambiense underwent 24-h polysomnographic recordings before treatment with melarsoprol and after each of three weekly treatment sessions. polysomnography consisted of a continuous recording of the electroencephalogram, electromyogram and electro-oculogram on a ... | 1999 | 10476010 |
| effects of humid heat exposure on human sleep stages and body temperature. | the objective of this study was to confirm the effect of humid heat exposure on sleep stages and body temperature. seven healthy male volunteers with a mean age of 22.7+/-1.63, served as the subjects. the experiments were carried out under four different conditions of room temperature and relative humidity: 29 degrees c rh 50% (29/50), 29 degrees c rh 75% (29/75), 35 degrees c rh 50% (35/50), and 35 degrees c rh 75% (35/75). the subjects wearing only shorts slept from 23:00 to 7:00 on a bed, whi ... | 1999 | 10505822 |
| time-on-task decrements in "steer clear" performance of patients with sleep apnea and narcolepsy. | loss of attention with time-on-task reflects the increasing instability of the waking state during performance in experimentally induced sleepiness. to determine whether patients with disorders of excessive sleepiness also displayed time-on-task decrements indicative of wake state instability, visual sustained attention performance on "steer clear," a computerized simple rt driving simulation task, was compared among 31 patients with untreated sleep apnea, 16 patients with narcolepsy, and 14 hea ... | 1999 | 10505827 |
| novel path to activation of vascular smooth muscle cells: up-regulation of gp130 creates an autocrine activation loop by il-6 and its soluble receptor. | this study describes a novel path to the activation of smooth muscle cells (smc) by the il-6/soluble il-6 receptor (sil-6r) system. human vascular smc constitutively express only scant amounts of il-6r and so do not respond to stimulation with this cytokine. we show that smc also do not constitutively express appreciable levels of gp130, which would render them sensitive to transsignaling by the il-6/sil-6r complex. because gp130 is generally believed not to be subject to regulation, smc would t ... | 1999 | 10510402 |
| sleep disturbances in children with human immunodeficiency virus infection. | to describe the sleep patterns and level of fatigue in children and adolescents (6-18 years of age) with hiv infection, compared with ethnic-, gender-, and age-matched healthy children in the home setting. | 1999 | 10545588 |
| circadian and sleep-dependent regulation of hormone release in humans. | daily oscillations characterize the release of nearly every hormone. the circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, generates circadian, approximately 24-hour rhythms in many physiologic functions. however, the observed hormonal oscillations do not simply reflect the output of this internal clock. instead, daily hormonal profiles are the product of a complex interaction between the output of the circadian pacemaker, periodic changes in behavior, light exposu ... | 1999 | 10548874 |
| twenty-four-hour pattern of intraocular pressure in the aging population. | to characterize the 24-hour pattern of intraocular pressure (iop) in a sample of the aging human population. | 1999 | 10549652 |
| impact of yellow fever on the developing world. | yellow fever (yf) has remained a disease of public health importance since it was first described in the fifteenth century. at different periods in human history, yf has caused untold hardship and indescribable misery among populations in the americas, europe, and africa. it brought economic disaster in its wake, constituting a stumbling block to development. yellow fever is an arboviral infection with three epidemiological transmission cycles between monkeys, mosquitoes, and humans. it is an ac ... | 1999 | 10582093 |
| a model-based interpretation of the biphasic daily pattern of sleepiness. | we developed a thermoregulatory model of sleep control based on the hypothesis that non-rapid eye-movement sleep participates in homeostatic thermoregulation. this model successfully reproduced several qualitative features of human sleep/wake cycles during entrained as well as the internally desynchronized states. among the reproduced features, generation mechanisms of the biphasic sleepiness distribution are studied here in the light of the model structure. harmonic analysis is employed for thi ... | 1999 | 10592016 |
| two circadian rhythms in the human electroencephalogram during wakefulness. | the influence of the circadian pacemaker and of the duration of time awake on the electroencephalogram (eeg) was investigated in 19 humans during approximately 40 h of sustained wakefulness. two circadian rhythms in spectral power density were educed. the first rhythm was centered in the theta band (4.25-8.0 hz) and exhibited a minimum approximately 1 h after the onset of melatonin secretion. the second rhythm was centered in the high-frequency alpha band (10.25-13.0 hz) and exhibited a minimum ... | 1999 | 10600925 |
| after-effect of entrainment on the period of human circadian system. | the purpose of the present study is to examine changes of the circadian period in humans during temporal isolation, where the circadian rhythm is free-running. twelve young males each spent 22 d alone in a temporal isolation room. rectal temperature was continuously recorded and plasma melatonin was measured on day 3 (d3) and from days 10 to 13 (d10-d13). the light intensity in the room was less than 100 lx during the waking period. the free-run period of temperature rhythm from d3 to d10 (24.75 ... | 1999 | 10603426 |
| short-term memory, alertness and performance: a reappraisal of their relationship to body temperature. | previous studies have led to the beliefs: (1) that short-term memory is best during the night when the body temperature is at its nadir, and (2) that the circadian rhythms of short-term memory and subjective alertness are driven by oscillators independent from each other and from the body temperature cycle. unfortunately, these conclusions, which would have major implications for understanding the organization of the human circadian timing system, are largely based on field and laboratory studi ... | 1992 | 10607021 |
| the relationship between circadian and hemicircadian components of human endogenous temperature rhythms. | a review of constant routine data from normative and phase-shifted subjects shows that the hemicircadian and circadian components of fitted temperature data are only weakly linked. in these data sets, on average, hemicircadian amplitude is one-third of the circadian amplitude and the hemicircadian minimum occurs 1.7 h earlier than the circadian minimum. however, their variations about these means are largely independent. in addition the hemicircadian component was much less affected by bright li ... | 1992 | 10607031 |
| circasemidian sleep propensity and the phase-amplitude maintenance model of human sleep/wake regulation. | evidence for circasemidian sleep/wake regulation is briefly reviewed with respect to protocols used to quantify sleep propensity. existing models of sleep/wake regulation are examined in view of their ability to accommodate data which demonstrate an afternoon sleep period. finally, a modelling approach is briefly outlined which emphasizes the maintenance of the phase and amplitude characteristics of the circadian rhythm of body (and brain) temperature and predicts the circasemidian phenomena. | 1992 | 10607032 |
| forced splitting of human sleep in free-running rhythms. | the assumption of polyphasic sleep/wake regulation is based on the occurrence of nap-sleep at specific phase positions in the circadian cycle. further support would be the split of the normal long major sleep episode into shorter components. evidence for this hypothesis comes from the discovery of bimodal distribution in sleep duration. an experimental approach to test this hypothesis has been carried out by restricting sleep duration in free-running rhythms. the outcome was a biphasic distribut ... | 1992 | 10607035 |
| diurnal sleep/wake-related immune functions during the menstrual cycle of healthy young women. | animal and human studies have related the sleeping/waking brain to the immune system. because women are more susceptible to certain immunological illnesses, and sex steroids regulate immune functions, it was investigated whether the diurnal sleep/wake pattern of aspects of cellular immune functions and interleukin-1 (il-1) and il-2-like activities differed during low and high progesterone phases of the menstrual cycle. eleven healthy women, mean age 24 y, were assessed over 24 h with serial veno ... | 1995 | 10607154 |