| phenotypic effects of leptin in an ectotherm: a new tool to study the evolution of life histories and endothermy? | leptin is a hormone that regulates energy expenditure and body mass in mammals, and it has attracted considerable attention because of its potential in treating human obesity. comprehensive data from both pathological and non-pathological systems strongly support a role for leptin in regulating energy metabolism, in thermoregulation and in regulating the onset of puberty. we report here that daily injections of recombinant murine leptin in fence lizards (sceloporus undulatus) produce phenotypic ... | 2000 | 10607539 |
| life after the oig gainsharing advisory bulletin. considering alternatives in the wake of the controversial opinion. | | 1999 | 10623051 |
| thermoregulatory model of sleep control: losing the heat memory. | thermoregulatory mechanisms were hypothesized to provide primary control of non-rapid-eye-movement sleep (nrem). on the basis of this hypothesis, we incorporated the thermoregulatory feedback loops mediated by the "heat memory," heat load, and loss processes associated with sleep-wake cycles, which were modulated by two circadian oscillators. in addition, hypnogenic warm-sensitive neurons (hwsns) were assumed to integrate thermoregulation and nrem control. the heat memory described above could b ... | 1999 | 10643752 |
| commentary: models of sleep regulation: successes and continuing challenges. | quantitative models have been developed to describe salient aspects of human sleep regulation. the two-process model of sleep regulation and the thermoregulatory model of sleep control highlight the interaction between sleep homeostasis and circadian rhythmicity and the association between sleep and temperature regulation, respectively. these models have been successful and inspiring, but continuing progress remains dependent on rigorous testing of some of their basic assumptions. whereas it has ... | 1999 | 10643754 |
| pharmacogenetics becomes pharmacogenomics: wake up and get ready. | | 1999 | 10671638 |
| diurnal preference, sleep habits, circadian sleep propensity and melatonin rhythm in healthy human subjects. | after 24-h sleep deprivation, 33 healthy young subjects entered the 10/20 min ultra-short sleep-wake schedule for 26 h. melatonin rhythm was hourly assessed simultaneously. results indicated that morning preference was significantly correlated with habitual sleep onset (r=-0.41, p=0.04), habitual sleep offset (r=-0.52, p=0.002), melatonin peak time (r=-0.36, p=0.04), and sleep propensity onset time (r=-0.36, p=0.04). the intervals between habitual sleep mid-point and melatonin peak time and betw ... | 2000 | 10675795 |
| endocrine activity during sleep. | almost all functions of humans are subject to cyclic changes and are governed by the nervous system. most rhythms are driven by an internal biological clock located in the hypothalamic suprachiasmatic nucleus (scn) and can be synchronized by external signals such as light-dark cycles. homeostatic activities such as body temperature, blood volume, water balance and sleep, are rhythmic. likewise, most hormones are secreted in a rhythmic fashion. both sleep and circadian effects interact to produce ... | 2000 | 10689633 |
| mammalian dna mismatch repair. | dna mismatch repair (mmr) is one of multiple replication, repair, and recombination processes that are required to maintain genomic stability in prokaryotes and eukaryotes. in the wake of the discoveries that hereditary nonpolyposis colorectal cancer (hnpcc) and other human cancers are associated with mutations in mmr genes, intensive efforts are under way to elucidate the biochemical functions of mammalian muts and mutl homologs, and the consequences of defects in these genes. genetic studies i ... | 1999 | 10690417 |
| [the characteristics of the electrodermal activity during changes in the level of human wakefulness]. | the wake-drowsiness transition during the performance of a monotonous psychomotor test was studied using polygraphic recording, with particular emphasis on changes in the electrodermal activity (eda) and occurrence of electrodermal reactions (edr). it was found that decrease in wakefulness was accompanied by a drop of the eda. the edr gradually disappeared for several minutes and did not reappear without activation; their dependence on sex and individual features of a subject significantly incre ... | 1999 | 10693272 |
| wakes and spokes: new motion-induced brightness illusions. | under certain conditions, high-contrast moving figures induce adjacent illusory regions, 'wakes' and 'spokes', which have contrast polarity opposite the inducing figures. in this paper we document properties of these novel phenomena. when the illusions are induced by a moving bar, spokes appear on the side of the bar closer to fixation and connect the bar to the fixation point, regardless of the momentary position of the bar or whether it is moving to the left or to the right. although spokes of ... | 1999 | 10694971 |
| genetic polymorphisms of human melatonin 1b receptor gene in circadian rhythm sleep disorders and controls. | recent studies suggest that melatonin 1b (mel1b) receptor, as well as melatonin 1a (mel1a) receptor, is involved in the modulation of circadian rhythms in mammals. mutational analysis was performed in the entire coding region of the human mel1b receptor gene using genomic dna from sleep disorder subjects. we have identified two missense mutations, g24e and l66f. however, neither is likely to be associated with sleep disorders in our study population. one of the subjects with non-24-h sleep-wake ... | 2000 | 10696804 |
| sleep stage-related changes in sympathetic sudomotor and vasomotor skin responses in man. | the aim of the study was to evaluate the characteristics of the spontaneous and evoked sympathetic skin responses (ssr) during sleep and wakefulness in comparison with the skin vasomotor responses (svr). | 2000 | 10699403 |
| the ageing of the low-frequency water disturbances caused by swimming goldfish and its possible relevance to prey detection. | wakes caused by swimming goldfish (carassius auratus) were measured with a particle image velocimetry system and analyzed using a cross-correlation technique. particle velocities in a horizontal plane (size of measuring plane 24 cmx32 cm or 20 cmx27 cm) were determined, and the vorticity in the plane was derived from these data. the wake behind a swimming goldfish can show a clear vortex structure for at least 30 s. particle velocities significantly higher than background noise could still be de ... | 2000 | 10708639 |
| the significance of tryptophan in infant nutrition. | in the newborn, tryptophan (trp) and its metabolites are essential to brain maturation and to the development of neurobehavioral regulations of food intake, satiation and sleep-wake-rhythm. due to the high trp concentration in human milk in relation to the total of neutral amino acids, the blood-brain transfer of tryptophan as a precursor of its metabolites serotonin and melatonin is optimal. in contrast, commercial infant formulas are lower in trp and higher in neutral amino acid levels resulti ... | 1999 | 10721122 |
| molecular mechanisms of sleep-wake regulation: a role of prostaglandin d2. | prostaglandin (pg) d2 is a major prostanoid in the brains of rats and other mammals, including humans. when pgd synthase (pgds), the enzyme that produces pgd2 in the brain, was inhibited by the intracerebroventricular infusion of its selective inhibitors, i.e. tetravalent selenium compounds, the amount of sleep decreased both time and dose dependently. the amount of sleep of transgenic mice, in which the human pgds gene had been incorporated, increased several fold under appropriate conditions. ... | 2000 | 10724461 |
| post-mortem orthopantomography--an aid in screening for identification purposes. | ante-mortem orthopantomograms may be of great value in the identification of human remains. this x-ray technique provides an overall view of the teeth and jaws and thus of numerous individual structural characteristics within a short time. standardised post-mortem orthopantomography has previously not been feasible in the forensic practice. the present study shows how orthopantomography can be applied to identification procedures. the reproduction of ante-mortem x-ray conditions is implemented h ... | 2000 | 10741478 |
| dose-dependent effects of endotoxin on human sleep. | the role of the central nervous system in the host response to infection and inflammation and modulation of these responses by the hypothalamic-pituitary-adrenal system are well established. in animals, activation of host defense mechanisms increases non-rapid eye movement (nrem) sleep amount and intensity, which, in turn, are thought to support host defense, or the body's ability to defend itself against challenges to its immune system. in humans, the evidence is conflicting. therefore, we inve ... | 2000 | 10749783 |
| pathophysiology of human circadian rhythms. | the 24 h profiles of hormonal secretions represent a good model for the study of the human circadian system. diurnal hormonal variations generally reflect the modulation of ultradian or pulsatile release at 1-2 h intervals by signals occurring at nearly 24 h periods and result from the interaction of an internal timekeeping system--or circadian clock--with the sleep-wake homeostasis and various environmental factors, including the light-dark cycle, periodic changes in activity levels and the mea ... | 2000 | 10752069 |
| the scientific basis for visible particle inspection. | the following paper was presented at the 1999 pda international conference in tokyo, japan february 24, 1999. the paper was written in response to the recent well-publicized incidents in japan in which the presence of visible particulates in injectable products was observed. these incidents should be considered a wake-up call to all concerned with injectable pharmaceutical products. the overview of visible particle inspection presented at the tokyo pda meeting is reprinted here as a reminder tha ... | 1999 | 10754727 |
| helicobacter infection in dogs and cats: facts and fiction. | the discovery of the spiral bacterium helicobacter pylori and its causative role in gastric disease in humans has brought a dramatic change to gastroenterology. although spiral bacteria have been known for more than a century to infect the stomachs of dogs and cats, recent research has been conducted mainly in the wake of interest in h. pylori. h. pylori has not been found in dogs and only very rarely in cats and zoonotic risk is minimal. a variety of other helicobacter spp. can infect the stoma ... | 2000 | 10772482 |
| understanding circadian rhythmicity in neurospora crassa: from behavior to genes and back again. | circadian clocks have been described in organisms ranging in complexity from unicells to mammals, in which they function to control daily rhythms in cellular activities and behavior. the significance of a detailed understanding of the clock can be appreciated by its ubiquity and its established involvement in human physiology, including endocrine function, sleep/wake cycles, psychiatric illness, and drug tolerances and effectiveness. because the clock in all organisms is assembled within the cel ... | 2000 | 10779395 |
| prostaglandin d synthase gene is involved in the regulation of non-rapid eye movement sleep. | to examine the function of prostaglandin (pg) d synthase (pgds) gene, as well as endogenously produced pgd(2) in sleep regulation in vivo, we generated transgenic (tg) mice that overexpress human pgds gene to study their sleep behavior. although no difference was observed in the sleep/wake patterns between wild-type and tg mice, a striking time-dependent increase in non-rapid eye movement (nrem), but not in rapid eye movement (rem), sleep was observed in two independent lines of tg mice after st ... | 2000 | 10781097 |
| sleep duration, illumination, and activity patterns in a population sample: effects of gender and ethnicity. | current knowledge of the population's sleep durations emanates primarily from questionnaires and laboratory studies. using actillumes, we investigated whether self-reported sleep durations were indicative of a population decline in sleep duration. we also explored illumination and activity patterns. | 2000 | 10807965 |
| hormonal and pharmacological manipulation of the circadian clock: recent developments and future strategies. | the mammalian circadian oscillator, located in the suprachiasmatic nuclei of the anterior hypothalamus, serves as the principal source of rhythmic temporal information for virtually all physiologic processes in the organism, including the alternating expression of sleep and wakefulness. recent studies, in both animal models and human subjects, have demonstrated the important modulation of sleep and wakefulness mediated by the circadian clock. independent of other factors, notably prior sleep-wak ... | 2000 | 10809190 |
| daily hunger sensation monitoring as a tool for investigating human circadian synchronization. | this study investigates within-day hunger sensation (hs) variability in clinically healthy subjects adapted to living in antarctica (chsala), as compared to their coeval subjects living in their mother country. the aim is to detect how the orectic stimulus behaves in those environmental conditions and occupational schemes, in order to investigate the individual synchronization to sleep-wake alternation and meal time schedule. hs was estimated via a self-rating score of its intensity on a visual ... | 2000 | 10840653 |
| contribution of circadian physiology and sleep homeostasis to age-related changes in human sleep. | the circadian pacemaker and sleep homeostasis play pivotal roles in vigilance state control. it has been hypothesized that age-related changes in the human circadian pacemaker, as well as sleep homeostatic mechanisms, contribute to the hallmarks of age-related changes in sleep, that is, earlier wake time and reduced sleep consolidation. assessments of circadian parameters in healthy young (approximately 20-30 years old) and older people (approximately 65-75 years old)--in the absence of the conf ... | 2000 | 10841208 |
| sexual orientation and the sleep-wake cycle: a preliminary investigation. | the sleep-wake cycle as a function of sexual orientation was investigated. male and female, heterosexual and homosexual subjects completed a sexual-orientation questionnaire and four sets of recording sheets of activities for a 16-day period. mean sleep duration was calculated from the record sheets using waking-up and going-to-sleep times. it was predicted that homosexual males and females would awake earlier, go to sleep later, and thus have shorter sleep duration compared to heterosexuals. th ... | 2000 | 10842721 |
| [psychiatric presentation of human african trypanosomiasis: overview of diagnostic pitfalls, interest of difluoromethylornithine treatment and contribution of magnetic resonance imaging]. | we report a case of a western african man, residing in france for 4 years, who developed human african trypanosomiasis (hat) caused by trypanosoma brucei gambiense. diagnosis was made at a late stage of the disease. the disease was misdiagnosed and untreated for several years because the clinical presentation was limited to psychiatric disorders and biological confirmation was difficult. polysomnographic recordings demonstrated typical alterations of hat. difluoromethylornithine was effective in ... | 2000 | 10844370 |
| individual differences in the phase and amplitude of the human circadian temperature rhythm: with an emphasis on morningness-eveningness. | we studied the relationship between the phase and the amplitude of the circadian temperature rhythm using questionnaires that measure individual differences in personality variables, variables that relate to circadian rhythms, age and sex. the ambulatory core body temperature of 101 young men and 71 young women was recorded continuously over 6 days. the temperature minimum (tmin) and amplitude (tamp) were derived by fitting a complex cosine curve to each day's data for each subject. participants ... | 2000 | 10849238 |
| chronic oral administration of cg-3703, a thyrotropin releasing hormone analog, increases wake and decreases cataplexy in canine narcolepsy. | the effects on cataplexy and daytime sleep of acute and chronic oral administration of cg-3703, a potent trh analog were assessed in canine narcolepsy. cg-3703 was found to be orally active and to reduce cataplexy (0.25 to 16 mg/kg) and sleep (8 and 16 mg/kg) in a dose-dependent manner. two-week oral administration of cg-3703 (16 mg/kg) significantly reduced cataplexy and daytime sleep. the anticataplectic effects of cg-3703 were not associated with changes in general behavior, heart rate, blood ... | 2000 | 10869884 |
| identification of mu-class glutathione transferases m2-2 and m3-3 as cytosolic prostaglandin e synthases in the human brain. | cytosolic prostaglandin (pg) e synthase was purified from human brain cortex. the n-terminal amino acid sequence, pmtlgyxnirgl, was identical to that of the human mu-class glutathione transferase (gst) m2 subunit. complementary dnas for human gstm2, gstm3, and gstm4 subunits were cloned, and recombinant proteins were expressed as homodimers in escherichia coli. the recombinant gstm2-2 and 3-3 catalyzed the conversion of pgh2 to pge2 at the rates of 282 and 923 nmol/min/mg of protein, respectivel ... | 2000 | 10905636 |
| implementing the integration of component services for reproductive health. | in the wake of the 1994 international conference on population and development in cairo, considerable activity has occurred both in national policymaking for reproductive health and in research on the implementation of the cairo program of action. this report considers how effectively a key component of the cairo agenda--integration of the management of sexually transmitted infections, including human immunodeficiency virus, with maternal and child health-family planning services--has been imple ... | 2000 | 10907280 |
| narcolepsy in children: a practical guide to its diagnosis, treatment and follow-up. | narcolepsy is a neurological syndrome characterised by daytime somnolence and cataplexy which often begins in childhood. failing to recognise the condition may lead to mislabelling a child as lazy or depressed. the diagnostic criteria for narcolepsy vary with age. in children 8 years and older a multiple sleep latency test with an average latency of less than 8 minutes, and 2 or more sleep onset rem episodes supports the diagnosis. human leucocyte antigen (hla) marker dqbeta1 -0602 has been asso ... | 2000 | 10937454 |
| [sleep disorders associated to prion diseases]. | introduction: description of sleep disorders associated to human prion diseases. development: the recent advances on pathology, genetics and immunocytochemistry are an outstanding contribution to the knowledge of transmissible spongiform encephalopathies and identification of possible new variants. despite decades of research, human prion diseases have remained enigmatic in many aspects. among these, the intricate connection between infectivity and genetics, genotype-phenotype correlation, patho ... | 2000 | 10951672 |
| developing circadian rhythmicity. | circadian rhythms are endogenously generated rhythms with a period length of about 24-hours. evidence gathered over the past decade indicates that the circadian timing system develops prenatally, and the suprachiasmatic nuclei, the site of a circadian clock, is present by midgestation in human and nonhuman primates. recent evidence also shows that the circadian system of primate infants is responsive to light at very premature stages and that low intensity lighting can regulate the developing cl ... | 2000 | 10975429 |
| human genetic susceptibility to tuberculosis. | recent advances in the understanding of human susceptibility to tuberculosis have resulted from the application of molecular techniques to answer mechanistic questions on genetic regulation of host defense. | 2000 | 10976382 |
| the influence of isolation on psychological and physiological variables. | human behavior is temporally organized by an endogenous "biological clock," and the alternation between activity and rest is an integral part of this system. like all other biological functions, the system is only capable of adapting to external stimuli to a limited (and recognizable) extent. | 2000 | 10993308 |
| linking 600-hz "spikelike" eeg/meg wavelets ("sigma-bursts") to cellular substrates: concepts and caveats. | somatosensory evoked human eeg and magnetoencephalographic (meg) responses comprise a brief burst of low-amplitude, high-frequency (approximately 600 hz) spikelike wavelets ("sigma-bursts") superimposed on the primary cortical response (e.g., the n20 to electrical median nerve stimulation). the recent surge of interest in these macroscopic sigma-burst responses is energized by the prospect of monitoring noninvasively, highly synchronized and rapidly repeating population spikes generated in the h ... | 2000 | 11012041 |
| the hypocretins: excitatory neuromodulatory peptides for multiple homeostatic systems, including sleep and feeding. | the hypocretins are two neuropeptides of related sequence that are produced from a common precursor whose expression is restricted to 1, 100 large neurons of the rat dorsal-lateral hypothalamus. the hypocretins have been detected immunohistochemically in secretory vesicles at synapses of fibers that project to areas within the posterior hypothalamus that are implicated in feeding behaviors and hormone secretion and diverse targets in other brain regions and in the spinal cord, including several ... | 2000 | 11020209 |
| diurnal variation in the p300 component of human cognitive event-related potential. | diurnal variation in the p300 component of the human cognitive event-related potential (erp) was examined. the p300 component is considered to be a measure of neuroelectric activity related to cognitive functions such as attention allocation and information processing. nine diurnally active healthy male subjects whose sleep-wake rhythms were synchronized prior to the experiment were studied. the p300 components oral temperature, heart rate, left- and right-hand grip strength, reaction time, subj ... | 2000 | 11023214 |
| interleukin-1beta induces cyclooxygenase-2 and prostaglandin e(2) synthesis in human neuroblastoma cells: involvement of p38 mitogen-activated protein kinase and nuclear factor-kappab. | prostaglandins (pgs), which are generated by the enzymatic activity of cyclooxygenase (cox)-1 and -2, modulate several functions in the cns such as the generation of fever, the sleep/wake cycle, and the perception of pain. moreover, the neuronal induction of cox-2 has been linked to neuroinflammatory aspects of alzheimer's disease (ad). the regulation of cox expression in neuronal cells is only partly understood and has been mainly linked to synaptic activity. in pathophysiological situations, h ... | 2000 | 11032891 |
| rapid-eye-movement sleep involves the memory-conversion circuits in a brain model. | people can remember the content of a dream in rapid eye movement (rem) sleep but cannot do so in slow-wave sleep. according to a brain model, memory is stored in encoding synapses as presynaptic axonal 'on-off' patterns and modulating synapses help encoding synapses convert short-term memory into long-term memory. these lead to the hypothesis that rem sleep involves modulating synapses of the memory-conversion circuits including the anterior nuclei and dorsomedial nuclei of the thalamus. cortica ... | 2000 | 11058419 |
| a benzodiazepine hypnotic facilitates adaptation of circadian rhythms and sleep-wake homeostasis to an eight hour delay shift simulating westward jet lag. | to determine whether appropriately timed administration of a short-acting benzodiazepine hypnotic, which has proven effective in an animal model of jet lag, also facilitates adaptation of circadian rhythmicity and sleep-wake homeostasis in a human model of jet lag. | 2000 | 11083601 |
| effects of lateral preoptic area application of orexin-a on sleep-wakefulness. | deficiency of orexin, a newly discovered hypothalamic peptide, is thought to lead to abnormal sleepiness and cataplexy in both human narcolepsy and animal models of the disease. as the poa contains extensive orexin terminals and is established as a sleep/arousal regulatory site, we evaluated a hypothesis that this site is a target for the arousal-inducing effects of orexin. orexin-a was microinjected into lateral preoptic area (ipoa) and the effects on sleep-wakefulness and brain temperature wer ... | 2000 | 11095491 |
| epithelial-mesenchymal transformation is the mechanism for fusion of the craniofacial primordia involved in morphogenesis of the chicken lip. | we have previously demonstrated that epithelial-mesenchymal transformation (emt) brings about tgf beta 3-induced confluence of craniofacial primordia that derive from the maxillary processes and give rise to the avian palate. the upper lip of the chick embryo forms by confluence of primordia also derived from the maxillary processes, but in this case, they fuse with the intermaxillary segment of the nasofrontal process. here, we ask whether the bilateral epithelial seams formed when these primor ... | 2000 | 11112334 |
| [neurological interpretation of dreams] . | cerebral cortical activity is constant throughout the entire human life, but substantially changes during the different phases of the sleep-wake cycle (wakefulness, non-rem sleep and rem sleep), as well as in relation to available information. in particular, perception of the environment is closely linked to the wake-state, while during sleep perception turns to the internal domain or endogenous cerebral activity. external and internal information are mutually exclusive. during wakefulness a neu ... | 2000 | 11143502 |
| cortical oscillations in human medial temporal lobe during wakefulness and all-night sleep. | we have recorded human medial temporal lobe electrocorticogram during wakefulness and natural sleep in epileptic patients with subdural electrodes. from these recordings, we have found gamma (30-150 hz) [neuroscience 90 (1999) 1149] and beta-1 (10-20 hz) [neuroreport 10 (1999) 3055] activities during wakefulness in human medial temporal lobe. in this paper, we will report changes of these frequencies across wake and natural sleep. electrocorticograms during wake, slow wave sleep and rapid eye mo ... | 2001 | 11164805 |
| modulation of the promoter region of prepro-hypocretin by alpha-interferon. | hypocretins 1 and 2 (also called orexins a and b, respectively) are hypothalamic neuropeptides that have recently been shown to be involved in the sleep disorder narcolepsy and possibly in the normal regulation of sleep and wake functions. these two peptides are derived from a single precursor molecule called prepro-hypocretin, also known as prepro-orexin. we have cloned a 450 bp fragment from the 5'-flanking region of the human prepro-hypocretin gene and demonstrated that this fragment has prom ... | 2001 | 11179675 |
| seasonal changes in human sleep-wake rhythm in antarctica and japan. | the subjects were eight men of the japanese antarctic research expedition (average age 35.8 years), and 10 healthy people living around kofu, japan (28.9 years). they completed a sleep log for 12 to 18 months, and the sleep-wake state was scored in 10-min epochs. q24 values calculated by chi2 periodgram were low in the antarctic midwinter. this means that there was difficulty in synchronizing to a 24-h period in the antarctic midwinter. in antarctica, sleep onset and offset times were delayed mo ... | 2000 | 11186114 |
| the suprachiasmatic nucleus projects to posterior hypothalamic arousal systems. | the suprachiasmatic nucleus (scn) temporally organizes behavior in part by sustaining arousal during the wake period of the sleep/wake cycle to consolidate adaptive waking behavior. in this study, we demonstrate direct projections from the scn, in both the rat and the human brains, to perikarya and proximal dendrites of two groups of posterior hypothalamic neurons with axonal projections that suggest they are important in the regulation of arousal, one producing hypocretins (hct) and the other m ... | 2001 | 11209963 |
| charcot-marie-tooth disease and sleep apnoea syndrome: a family study. | charcot-marie-tooth (cmt) disease is a genetically heterogeneous group of hereditary motor and sensory polyneuropathies in which sleep apnoea has rarely been reported and no causal relation shown. we looked for an association between the most common subtype of cmt disease (cmt1a) and sleep apnoea syndrome. | 2001 | 11214130 |
| evidence from the waking electroencephalogram that short sleepers live under higher homeostatic sleep pressure than long sleepers. | we used the waking electroencephalogram to study the homeostatic sleep regulatory process in human short sleepers and long sleepers. after sleeping according to their habitual schedule, nine short sleepers (sleep duration < 6 h) and eight long sleepers (> 9 h) were recorded half-hourly during approximately 40 h of wakefulness in a constant routine protocol. within the frequency range of 0.25-20.0 hz, spectral power density in the 5.25-9.0 and 17.25-18.0 hz ranges was higher in short sleepers tha ... | 2001 | 11226688 |
| human melatonin regulation is not mediated by the three cone photopic visual system. | the aim of this study was to test if the three cone photopic visual system is the primary ocular photoreceptor input for human circadian regulation by determining the effects of different wavelengths on light-induced melatonin suppression. healthy subjects with stable sleeping patterns (wake-up time 7:30 am +/- 12 min) and normal color vision were exposed at night to full-field 505 nm or 555 nm monochromatic stimuli or darkness for 90 min. plasma collected before and after exposures was quantifi ... | 2001 | 11232036 |
| prenatal nicotine alters vigilance states and achr gene expression in the neonatal rat: implications for sids. | maternal smoking is a major risk factor for sudden infant death syndrome (sids). the mechanisms by which cigarette smoke predisposes infants to sids are not known. we examined the effects of prenatal nicotine exposure on sleep/wake ontogenesis and central cholinergic receptor gene expression in the neonatal rat. prenatal nicotine exposure transiently increased sleep continuity and accelerated sleep/wake ontogeny in the neonatal rat. prenatal nicotine also upregulated nicotinic and muscarinic cho ... | 2001 | 11247836 |
| bovine spongiform encephalopathy and variant creutzfeldt-jakob disease: background, evolution, and current concerns. | the epidemic of bovine spongiform encephalopathy (bse) in the united kingdom, which began in 1986 and has affected nearly 200,000 cattle, is waning to a conclusion, but leaves in its wake an outbreak of human creutzfeldt-jakob disease, most probably resulting from the consumption of beef products contaminated by central nervous system tissue. although averaging only 10-15 cases a year since its first appearance in 1994, its future magnitude and geographic distribution (in countries that have imp ... | 2001 | 11266289 |
| experimental immunomodulation, sleep, and sleepiness in humans. | infection, inflammation, and autoimmune processes are accompanied by serious disturbances of well-being, psychosocial functioning, cognitive performance, and behavior. here we review those studies that have investigated the effects of experimental immunomodulation on sleep and sleepiness in humans. in most of these studies bacterial endotoxin was injected intravenously to model numerous aspects of infection including the release of inflammatory cytokines. these studies show that human sleep-wake ... | 2000 | 11268376 |
| neural plasticity and cognitive development. | it has been well documented that the effects of early occurring brain injury are often attenuated relative to later occurring injury. the traditional neuropsychological account of these observations is that, although the developing neural system normally proceeds along a well-specified maturational course, it has a transient capacity for plastic reorganization that can be recruited in the wake of injury. this characterization of early neural plasticity is limited and fails to capture the much mo ... | 2000 | 11280966 |
| decreased nocturnal levels of prolactin and growth hormone in women with fibromyalgia. | fibromyalgia (fm) is a complex syndrome, primarily of women, characterized by chronic pain, fatigue, and sleep disturbance. altered function of the somatotropic axis has been documented in patients with fm, but little is known about nocturnal levels of prl. as part of a laboratory study of sleep patterns in fm, we measured the serum concentrations of gh and prl hourly from 2000--0700 h in a sample of 25 women with fm (mean, 46.9 +/- 7.6 yr) and in 21 control women (mean, 42.6 +/- 8.1 yr). the me ... | 2001 | 11297602 |
| low-amplitude propagated contractile waves: a relevant propulsive mechanism of human colon. | human colonic motility is still poorly understood, especially as far as concerns its propulsive function. available data refer almost exclusively to the forceful propulsive activity, which is recognized as high-amplitude propagated contractions, the manometric equivalent of mass movements. by contrast, information on less vigorous propulsive contractions is still lacking. | 2001 | 11303973 |
| association of structural polymorphisms in the human period3 gene with delayed sleep phase syndrome. | recent progress in biological clock research has facilitated genetic analysis of circadian rhythm sleep disorders, such as delayed sleep phase syndrome (dsps) and non-24-h sleep-wake syndrome (n-24). we analyzed the human period3 (hper3) gene, one of the human homologs of the drosophila clock-gene period (per), as a possible candidate for rhythm disorder susceptibility. all of the coding exons in the hper3 gene were screened for polymorphisms by a pcr-based strategy using genomic dna samples fro ... | 2001 | 11306557 |
| societal response to hurricane mitch and intra- versus intergenerational equity issues: whose norms should apply? | late in the 1998 hurricane season, central america was slammed by a devastating hurricane. honduras, nicaragua. el salvador, guatemala, and belize were greatly impacted by hurricane mitch, one of the deadliest storms to affect the region in the past 200 years. the economies of each of these countries were badly affected. in the case of honduras-at the time the fourth-poorest country in latin america-its president suggested that 50 years of progress had been wiped out by the floods and mudslides ... | 2000 | 11314736 |
| sleep and sleep-wake cycle in an 81-year-old patient with de novo ultra-rapid cycling bipolar disorder. | this is a case report of an 81-year-old man who developed de novo bipolar disorder with ultrarapid cycling at the age of 80. mood was self-rated daily over a period of ten weeks; in addition, polysomnographic and motor activity recordings were performed during a drug-free baseline period. both depressive and hypomanic episodes had an average duration of about 30 hours; the affective cycle was thus independent from the sleep-wake cycle. when mood shifts occurred during nighttime, sleep was differ ... | 2001 | 11315515 |
| behavioural-genetic perspectives on personality function. | in the wake of the recent announcements that the human genome has been mapped, efforts to identify the genetic loci underlying personality function will grow and intensify. much research has already been done in this area, but it has for the most part been limited to classical biometrical approaches designed to determine if personality has a heritable basis. these so-called "heritability" studies estimate how much of the individual differences in personality are attributable to genetic differenc ... | 2001 | 11320677 |
| defining the states of consciousness. | consciousness remains an elusive concept due to the difficulty to define what has been regarded for many years as a subjective experience, therefore irrelevant for scientific study. recent development in this field of research has allowed to provide some new insight to a possible way to define consciousness. going through the extensive literature in this domain, several perspectives are proposed to define this concept. (1) consciousness and attention may not reflect the same process. (2) conscio ... | 2001 | 11323082 |
| on-line detection of sleep-wake states and application to produce intermittent hypoxia only in sleep in rats. | sleep-disordered breathing is associated with adverse clinical consequences such as daytime sleepiness and hypertension. the mechanisms behind these associations have been studied in animal models, especially rats, but intermittent stimuli such as hypoxia have been applied without reference to sleep-wake states. to determine mechanisms underlying the adverse physiological consequences of stimuli associated with sleep-disordered breathing requires criteria for detection of sleep-wake states on-li ... | 2001 | 11356775 |
| environmental pesticide exposure in honduras following hurricane mitch. | to investigate whether environmental contamination occurred in the wake of hurricane mitch (30-31 october 1998), we conducted a population-based cross-sectional household survey in the barrio of istoca, department of choluteca, honduras. the goals were to evaluate chemical contamination of potable water and the extent of human exposure to chemicals as a result of extensive flooding. | 2003 | 11357206 |
| hospital agrees to adopt policies in wake of patient's lawsuit. | the george washington university medical center has agreed to change its policies following a complaint by a patient that he was denied open-heart surgery due to his hiv-positive status. ronald flowers filed a suit after two surgeons, david alyono and benjamin aaron, recommended anticoagulant treatment instead of surgery. flowers had the surgery performed elsewhere. the justice department intervened in the case and reached an agreement with the hospital that will prohibit doctors from denying tr ... | 1998 | 11365243 |
| complex sound processing during human rem sleep by recovering information from long-term memory as revealed by the mismatch negativity (mmn). | perceptual learning is thought to be the result of neural changes that take place over a period of several hours or days, allowing information to be transferred to long-term memory. evidence suggests that contents of long-term memory may improve attentive and pre-attentive sensory processing. therefore, it is plausible to hypothesize that learning-induced neural changes that develop during wakefulness could improve automatic information processing during human rem sleep. the mmn, an objective me ... | 2001 | 11368962 |
| mouse model for morningness/eveningness. | human morning/evening preferences has recently been reported to be associated with polymorphism of the 3' flanking region of the clock gene, which was the first identified mammalian circadian clock gene. we recorded body temperature, spontaneous activity, electroencephalogram and electromyogram for 48 h in mice with jcl:icr genetic background and homozygous for the clock mutation (cl/cl on jcl:icr). in both wild-type and cl/cl on jcl:icr, body temperature, activity, wake and sleep were completel ... | 2001 | 11388430 |
| predicting behavioral changes associated with age-related cognitive impairment in dogs. | to monitor the progression of age-related behavioral changes in dogs during a period of 6 to 18 months and to determine whether signs of dysfunction in any of 4 behavioral categories can be used to predict further impairment. | 2001 | 11394832 |
| human aging and melatonin. clinical relevance. | melatonin is a hormone produced mainly by the pineal gland and secreted primarily at night, when it reaches levels 10 times higher than those present in the daytime. the highest melatonin levels are found in children younger than 4 yr; thereafter melatonin levels begin to decline with age. as a chronobiotic, melatonin acts on sleep by phase-advancing or delaying the sleep--wake cycle so that sleep onset occurs earlier or later than usual. beneficial effects of melatonin have been observed in del ... | 2001 | 11404053 |
| phase-advance shifts of human circadian pacemaker are accelerated by daytime physical exercise. | effects of forced sleep-wake schedules with and without physical exercise were examined on the human circadian pacemaker under dim light conditions. subjects spent 15 days in an isolation facility separately without knowing the time of day and followed a forced sleep-wake schedule of a 23 h 40-min period for 12 cycles, and physical exercise was imposed twice per waking period for 2 h each with bicycle- or rowing-type ergometers. as a result, plasma melatonin rhythm was significantly phase advanc ... | 2001 | 11404294 |
| mastering the value chain. an interview with mark levin of millennium pharmaceuticals. interview by david champion. | as today's business leaders are all too aware, a new scientific or technological break-through can quickly transform an industry's competitive landscape. the upheaval is often traumatic for the companies involved, forcing them to rethink their strategies and redefine their boundaries. but an industry in flux also creates vast opportunities. to seize them, companies must see how the current upheavals will affect the future distribution of profits--and then reinvent themselves to capitalize on the ... | 2001 | 11408971 |
| drug discovery in the wake of genomics. | | 2001 | 11434347 |
| familial advanced sleep phase syndrome. | the circadian rhythms of sleep propensity and melatonin secretion are regulated by a central circadian clock, the suprachiasmatic nucleus of the hypothalamus. the most common types of sleep disorders attributed to an alteration of the circadian clock system are the sleep/wake cycle phase disorders, such as delayed sleep phase syndrome and advanced sleep phase syndrome (asps). advanced sleep phase syndrome is characterized by the complaint of persistent early evening sleep onset and early morning ... | 2001 | 11448298 |
| [sleeping sickness, a reemerging sickness]. | human african trypanosomiasis (tha) has reappeared in most intertropical countries of black africa and an estimated 400,000 new cases are reported every year. genetic tests which now make possible the differentiation of morphologically similar trypanosome subspecies showed that a large variety of game and domestic animals act as reservoir hosts of trypanosoma brucei gambiense, thus making it even more difficult to fight the disease. the detection of cases and their treatment are absolutely neces ... | 2000 | 11471250 |
| naturally occurring benzodiazepines may codetermine chronotypes. | determinants of individual differences in sleep-wake cycles and vigilance are being recognized as major factors of influence in both physical and mental health. alterations of an accustomed circadian sleep-wake rhythm are commonly seen in the early stages of the majority of psychiatric disorders and, by themselves, predispose to significant morbidity even in the absence of an underlying illness. while it is well known that disruptions of sleep respond favourably to benzodiazepines, agents which ... | 2001 | 11478424 |
| physician satisfaction with two order entry systems. | in the wake of the institute of medicine report, to err is human: building a safer health system (lt kohn, jm corrigan, ms donaldson, eds; washington, dc: national academy press, 1999), numerous advisory panels are advocating widespread implementation of physician order entry as a means to reduce errors and improve patient safety. successful implementation of an order entry system requires that attention be given to the user interface. the authors assessed physician satisfaction with the user in ... | 2001 | 11522770 |
| effects of restraint and cabin environment on skin temperature, sleep-wake, feeding and drinking circadian rhythms in macaca mulatta during spacelab flight simulation. | exposure to a weightless environment such as in spaceflight, leads to a number of physiological responses to assure the survival of an organism in this new environment. however, the real effect of microgravity itself has not been clearly established yet. considering the environmental and operational characteristics of a spaceflight, and as it has been shown in previous flights, the use of animals, and more particularly the non-human primates, takes on importance in understanding the mechanisms ... | 1994 | 11538769 |
| sleep-wake cycles in rhesus monkeys during spacelab flight simulations. | neurophysiological data has been obtained in orbital flight from various non-human primates. aboard russian satellites during both bion and biocosmos missions, impairments in duration and organization of the states of vigilance were observed in rhesus monkeys during flight: increase in nocturnal awakening, decrease of rapid eye movements-sleep (rem-sleep). it was assumed that weightlessness played a role in these changes. the former "rhesus project", a joint program between cnes and nasa, was ... | 1995 | 11538931 |
| evolution of sleep and wakefulness organization in macaca mulatta during spacelab flight simulation. | nasa and cnes agencies planned to perform neurophysiological studies aboard spacelab using rhesus monkeys as human models. the present study was conducted to assess the influence of restraint and confinement conditions on the circadian sleep-wake rhythm before an actual flight. three experimental 18-day flight simulations were performed on 6 adult macaca mulatta, chair-restrained in a high-fidelity mock-up of the spacelab compartment. wakefulness, non-rem sleep and rem-sleep were determined by a ... | 1997 | 11541867 |
| human sleep-wake cycles in the high arctic: effects of unusual photoperiodicity in a natural setting. | studies of human circadian rhythms are typically conducted in artificial environments that are low in ecological validity. in the current study, six subjects and the field director lived in temporal isolation in a completely natural environment with constant daylight (a high arctic research camp) for six weeks. detailed daily sleep logs were kept. in keeping with past findings, five of the six subjects developed a free-running sleep-wake cycle longer than 24 hours. unlike past results, the isola ... | 1995 | 11542647 |
| sleep-wake differences in scaling behavior of the human heartbeat: analysis of terrestrial and long-term space flight data. | we compare scaling properties of the cardiac dynamics during sleep and wake periods for healthy individuals, cosmonauts during orbital flight, and subjects with severe heart disease. for all three groups, we find a greater degree of anticorrelation in the heartbeat fluctuations during sleep compared to wake periods. the sleep-wake difference in the scaling exponents for the three groups is comparable to the difference between healthy and diseased individuals. the observed scaling differences are ... | 1999 | 11542917 |
| evidence for a biological dawn and dusk in the human circadian timing system. | 1. because individuals differ in the phase angle at which their circadian rhythms are entrained to external time cues, averaging group data relative to clock time sometimes obscures abrupt changes that are characteristic of waveforms of the rhythms in individuals. such changes may have important implications for the temporal organization of human circadian physiology. 2. to control for variance in phase angle of entrainment, we used dual internal reference points--onset and offset of the nocturn ... | 2001 | 11559786 |
| history, heterogeneity, developmental biology, and functions of quiescent hepatic stellate cells. | in 1876, von kupffer described liver sternzellen (star-shaped cells). the functions of these cells remained enigmatic for 75 years until ito observed lipid-containing perisinusoidal cells in human liver. in 1971, wake demonstrated that the sternzellen of von kupffer and the fat-storing cells described by ito were identical. wake also established that these cells were important sites of vitamin a storage. soon thereafter, kent and popper demonstrated that the stellate cells were intimately linked ... | 2001 | 11586463 |
| autoantibodies to pancreatic hsp60 precede the development of glucose intolerance in patients with cystic fibrosis. | persons expressing the genetic disease cystic fibrosis (cf) suffer from a high risk of developing impaired glucose tolerance and diabetes. the development of diabetes in cf has been attributed, in the past, to the destruction of pancreatic islets and their resident beta-cells secondary to the destruction of the surrounding tissue by mechanical clogging of the pancreatic exocrine ducts. however, the discovery that autoimmunity to the 60-kda heat shock protein (hsp60) may cause type i diabetes in ... | 2001 | 11591125 |
| bloodborne pathogens: updating sharps safety. | osha's new compliance directive was a wake-up call telling healthcare employers they must use safer technology and safer work practices. | 2001 | 11602984 |
| predictors of incidence and prevalence of green tobacco sickness among latino farmworkers in north carolina, usa. | the characteristics of some populations make epidemiological measurement extremely difficult. the objective of this study is to identify risk factors that explain variation among incidence densities and proportions of one occupational illness, green tobacco sickness, within one such special population, latino migrant and seasonal farmworkers in the united states. | 2001 | 11604438 |
| neuroimmunologic aspects of sleep and sleep loss. | the complex and intimate interactions between the sleep and immune systems have been the focus of study for several years. immune factors, particularly the interleukins, regulate sleep and in turn are altered by sleep and sleep deprivation. the sleep-wake cycle likewise regulates normal functioning of the immune system. although a large number of studies have focused on the relationship between the immune system and sleep, relatively few studies have examined the effects of sleep deprivation on ... | 2001 | 11607924 |
| new rules for new drugs: the challenge of aids to the regulatory process. | | 1990 | 11650413 |
| uk drug trials: row over student trial. | the british medicines commission has undertaken an urgent review of arrangements for testing new drugs on healthy volunteers in the wake of charges that one company, charterhouse clinical research unit ltd., was using london students in toxicity tests of an antitumor drug without having informed the volunteers' physicians of the risks involved and without plans for long-term monitoring of the participants' health. under current british law, drug studies with healthy volunteers are regarded as a ... | 1984 | 11653526 |
| sequence variation and disease in the wake of the draft human genome. | the sequencing phase of the human genome project will soon be over. in its wake, repertoires of sequence polymorphisms among the human population are being sampled and a battery of functional genomics projects, from gene and protein expression studies to whole proteome interaction experiments, are generating vast quantities of data. now that the data, or the means to generate data, are available it is the application of this information in enhancing our understanding of biology that represents t ... | 2001 | 11673403 |
| state monitoring activities related to pfiesteria-like organisms. | in response to potential threats to human health and fish populations, six states along the east coast of the united states initiated monitoring programs related to pfiesteria-like organisms in 1998. these actions were taken in the wake of toxic outbreaks of pfiesteria piscicida steidinger & burkholder in maryland during 1997 and previous outbreaks in north carolina. the monitoring programs have two major purposes. the first, rapid response, is to ensure public safety by responding immediately t ... | 2001 | 11677180 |
| comparison of the effect of fatty alcohols on the permeation of melatonin between porcine and human skin. | melatonin (mt) is a hormone secreted by the pineal gland that plays an important role in the regulation of the circadian sleep-wake cycle. it would be advantageous to administer mt using a transdermal delivery system for the treatment of sleep disorders such as delayed sleep syndrome, jet lag in travelers, cosmonauts and shift workers. the porcine skin has been found to have similar morphological and functional characteristics as human skin. the elastic fibres in the dermis, enzyme pattern of th ... | 2001 | 11689256 |
| intrinsic near-24-h pacemaker period determines limits of circadian entrainment to a weak synchronizer in humans. | endogenous circadian clocks are robust regulators of physiology and behavior. synchronization or entrainment of biological clocks to environmental time is adaptive and important for physiological homeostasis and for the proper timing of species-specific behaviors. we studied subjects in the laboratory for up to 55 days each to determine the ability to entrain the human clock to a weak circadian synchronizing stimulus [scheduled activity-rest cycle in very dim (approximately 1.5 lux in the angle ... | 2001 | 11717461 |
| mechanisms and clinical significance of circadian rhythms in children. | circadian rhythms are endogenously generated rhythms with a period length of about 24 hours. a biologic clock in the hypothalamic suprachiasmatic nuclei is responsible for the generation of circadian rhythms. notable examples of the circadian rhythms include the sleep-wake cycle and rhythms in hormone production. abnormalities of the circadian system include biologic clock lesions that result in arrhythmic behavior and irregular sleep patterns. abnormalities of the circadian system also occur wh ... | 2001 | 11717562 |
| the effect of prone positioning on intraocular pressure in anesthetized patients. | ocular perfusion pressure is commonly defined as mean arterial pressure minus intraocular pressure (iop). changes in mean arterial pressure or iop can affect ocular perfusion pressure. iop has not been studied in this context in the prone anesthetized patient. | 2001 | 11748391 |
| neural basis and biological function of masking by light in mammals: suppression of melatonin and locomotor activity. | light influences mammalian circadian rhythms in two different ways: (1) it entrains endogenous oscillators (clocks), which regulate physiology and behavior; and (2) it affects directly and often immediately physiology and behavior (these effects are also referred to as masking). masking effects of light on pineal melatonin, locomotor activity, and the sleep-wake cycle in mammals and man are reviewed. they seem to represent a universal response in this group. the review reveals that the mechanism ... | 2001 | 11763983 |
| retinal circadian rhythms in humans. | circadian rhythms in the retina may reflect intrinsic rhythms in the eye. previous reports on circadian variability in electrophysiological human retinal measures have been scanty, and the results have been somewhat inconsistent. we studied the circadian variation of the electrooculography (eog), electroretinography (erg), and visual threshold (vth) in subjects undergoing a 36h testing period. we used an ultrashort sleep-wake cycle to balance effects of sleep and light-dark across circadian cycl ... | 2001 | 11777083 |
| sleep-waking discharge patterns of neurons recorded in the rat perifornical lateral hypothalamic area. | the perifornical lateral hypothalamic area (pf-lha) has been implicated in the control of several waking behaviours, including feeding, motor activity and arousal. several cell types are located in the pf-lha, including projection neurons that contain the hypocretin peptides (also known as orexins). recent findings suggest that hypocretin neurons are involved in sleep-wake regulation. loss of hypocretin neurons in the human disorder narcolepsy is associated with excessive somnolence, cataplexy a ... | 2002 | 11790824 |