Persistent 24-h variations of urinary 6-hydroxy melatonin sulphate and cortisol in Antarctica

Bright light (2000-3000 lux) of sufficient intensity to suppress human melatonin secretion, acts as a strong zeitgeber in the entrainment of circadian rhythms in man. In polar conditions, light of this intensity is not experienced for several weeks during the winter. The entrainment of human circadian rhythms, in particular that of melatonin, is clearly of interest in these circumstances. Urinary 6-hydroxy melatonin sulphate (aMT6s) is a good index of melatonin secretion in man. In a limited study of seven male volunteers living on an Antarctic base the overall 24-h rhythm of aMT6s excretion was maintained at four different times of year (spring, summer, autumn and winter) and no significant seasonal effects were noted. Cortisol excretion, appeared to be markedly affected by the season although other factors such as social and environmental stress cannot be discounted. These observations suggest that in the absence of a strong light-dark cycle melatonin production may be entrained by other factors.     

Persistent 24-h variations of urinary 6-hydroxy melatonin sulphate and cortisol in Antarctica

Summary Bright light (2000–3000 lux) of sufficient intensity to suppress human melatonin secretion, acts as a strong zeitgeber in the entrainment of circadian rhythms in man. In polar conditions, light of this intensity is not experienced for several weeks during the winter. The entrainment of human circadian rhythms, in particular that of melatonin, is clearly of interest in these circumstances. Urinary 6-hydroxy melatonin sulphate (aMT6s) is a good index of melatonin secretion in man. In a limited study of seven male volunteers living on an Antarctic base the overall 24-h rhythm of aMT6s excretion was maintained at four different times of year (spring, summer, autumn and winter) and no significant seasonal effects were noted. Cortisol excretion, appeared to be markedly affected by the season although other factors such as social and environmental stress cannot be discounted. These observations suggest that in the absence of a strong light-dark cycle melatonin production may be entrained by other factors.     

Arousal deficit shown in aged rat's quantitative EEG and ameliorative action of pramiracetam compared to piracetam

The basal EEG profile of the aged Fisher-344 rat was consistently different from that of the young rat, showing dominant high voltage slow-wave components. These slow waves were present in both the frontal cerebral cortex and dorsal hippocampus. Absent or greatly attenuated in the aged rat's hippocampal EEG was rhythmic theta activity, which was always dominant in the young awake rat's hippocampus. These EEG differences were clearly apparent only under basal test conditions, i.e., following habituation to the test situation. Pramiracetam sulfate acted strongly to normalize the aged rat's EEG, while the action of piracetam was weak and appeared to undergo tolerance development.     

Arousal deficit shown in aged rat's quantitative EEG and ameliorative action of pramiracetam compared to piracetam

Summary The basal EEG profile of the aged Fisher-344 rat was consistently different from that of the young rat, showing dominant high voltage slow-wave components. These slow waves were present in both the frontal cerebral cortex and dorsal hippocampus. Absent or greatly attenuated in the aged rat's hippocampal EEG was rhythmic theta activity, which was always dominant in the young awake rat's hippocampus. These EEG differences were clearly apparent only under basal test conditions, i.e, following habituation to the test situation. Pramiracetam sulfate acted strongly to normalize the aged rat's EEG, while the action of piracetam was weak and appeared to undergo tolerance development.     

Deficiency of fibrinolytic enzyme activities in the serum of patients with Alzheimer-type dementia

Previously we reported that there is a kallikrein deficiency in the cerebral tissue of patients with Alzheimer-type dementia. The present study was performed to investigate protease changes in the serum of these patients. The results showed that the kallikrein activity was normal, but that the activities of plasmin and urokinase were significantly low. The present findings indicate a derangement in the clotting and fibrinolytic systems in Alzheimer patients.     

Deficiency of fibrinolytic enzyme activities in the serum of patients with Alzheimer-type dementia.

Previously we reported that there is a kallikrein deficiency in the cerebral tissue of patients with Alzheimer-type dementia. The present study was performed to investigate protease changes in the serum of these patients. The results showed that the kallikrein activity was normal, but that the activities of plasmin and urokinase were significantly low. The present findings indicate a derangement in the clotting and fibrinolytic systems in Alzheimer patients.     

Human slow wave sleep: A review and appraisal of recent findings,with implications for sleep functions,and psychiatric illness

Recent findings concerning human slow wave sleep (hSWS-stages 3+4; delta EEG activity) are critically reviewed. Areas covered include the significance of the first hSWS cycle; hSWS in extended sleep; relationship between hSWS, prior wakefulness and sleep loss; hSWS influence on sleep length; problems with hSWS deprivation; influence of the circadian rhythm; individual differences in hSWS, especially, age, gender and constitutional variables such as physical fitness and body composition. Transient increases in hSWS can be produced by increasing both the quality and quantity of prior wakefulness, with an underlying mechanism perhaps relating to the waking level of brain metabolism. Whilst there may also be thermoregulatory influences on hSWS, hypotheses that energy conservation and brain cooling are major roles for hSWS are debatable. hSWS seems to offer some form of cerebral recovery, with the prefrontal cortex being particularly implicated. The hSWS characteristics of certain forms of major psychiatric disorders may well endorse this prefrontal link.     

Human slow wave sleep: a review and appraisal of recent findings, with implications for sleep functions, and psychiatric illness.

Recent findings concerning human slow wave sleep (hSWS-stages 3 + 4; delta EEG activity) are critically reviewed. Areas covered include the significance of the first hSWS cycle; hSWS in extended sleep; relationship between hSWS, prior wakefulness and sleep loss; hSWS influence on sleep length; problems with hSWS deprivation; influence of the circadian rhythm; individual differences in hSWS, especially, age, gender and constitutional variables such as physical fitness and body composition. Transient increases in hSWS can be produced by increasing both the quality and quantity of prior wakefulness, with an underlying mechanism perhaps relating to the waking level of brain metabolism. Whilst there may also be thermoregulatory influences on hSWS, hypotheses that energy conservation and brain cooling are major roles for hSWS are debatable. hSWS seems to offer some form of cerebral recovery, with the prefrontal cortex being particularly implicated. The hSWS characteristics of certain forms of major psychiatric disorders may well endorse this prefrontal link.     

Sex differences in human circadian rhythms: Intrinsic periods and sleep fractions

Summary The period of freerunning circadian rhythms is significantly shorter and the fraction of sleep is significantly larger in human females than in males, as long as the rhythms run internally synchronized. The sex difference in the period could be a property either of the whole circadian system or of only one of the oscillators in a multi-oscillator system. The sex difference in the sleep fraction could be a fixed property of the sleep-wake rhythm or could depend on interactions in the multi-oscillator system. To investigate these questions, a sample of 33 long-term experiments, in which the rhythms ran internally synchronized in one section and internally desynchronized in another section, were analyzed. The periods of rhythms in rectal temperature were different in females and males during internal synchronization, but became identical during internal desynchronization. In contrast, sex differences in sleep-wake periods were more pronounced when the rhythms were desynchronized than when they were internally synchronized. This result provides evidence that the sex difference in periodicity is a property only of the sleep-wake rhythm; the intrinsic periods of temperature rhythms are identical in females and males, whereas those of sleep-wake rhythms are distinctly shorter in females than in males. In the state of internal synchronization, the joint period is a compromise between the intrinsic periods of the rhythms involved, and therefore it shows a small but significant sex difference. Moreover, the transition from internally synchronized to desynchronized rhythms is combined with a highly significant reduction in the sleep fraction, which is considerably greater in females than in males. These results suggest that the occurrence of internal desynchronization strongly affects the sleep-wake rhythm, and that the influence of rhythm disorders is considerably greater in females than in males.     

Diurnal change in stature: effects of sleep deprivation in young men and middle-aged men

Sleep deprivation was associated with decreased stature and it blunted the normal 24-h rhythm in young and in middle-aged men. Loss in stature was regained during the first recovery night of sleep. The 24-h rhythm in height is not an endogenous circadian rhythm but depends upon the periods of recumbency over the sleep/wake cycle.     

Diurnal change in stature: effects of sleep deprivation in young men and middle-aged men

Summary Sleep deprivation was associated with decreased stature and it blunted the normal 24-h rhythm in young and in middle-aged men. Loss in stature was regained during the first recovery night of sleep. The 24-h rhythm in height is not an endogenous circadian rhythm but depends upon the periods of recumbency over the sleep/wake cycle.Acknowledgments. The first author was a Medical Research Council scholar; the second was supported by the Scottish Hospital Endowments Research Trust.     

Spectrum of Aeromonas and Plesiomonas infections in patients with cancer and AIDS

The spectrum of infection with Aeromonas and Plesiomonas included gastroenteritis, bacteremia, biliary tract infection, perirectal infection, and disseminated disease. Most patients (86%) with bacteremia were neutropenic (less than 500 PMN/mm3). Colonization of stools and sputum also occurred. Therapy with aminoglycosides, beta-lactams, trimethoprim/sulfamethoxazole, and the newer quinolones was effective in patients with AIDS and cancer.     

Hepatocellular iron-containing deposits in relatives of patients with latent idiopathic hemochromatosis: a qualitative and quantitative approach.

The quantitative and qualitative study in electron microscopy of hepatic fragments taken in apparently healthy collaterals of idiopathic hemochromatosis, shows the presence of siderosis, undetectable by Perls reaction comparatively with normal liver samples.     

CD24 interacts with and promotes the activity of c-src within lipid rafts in breast cancer cells, thereby increasing integrin-dependent adhesion

Expression of the glycosylphosphatidylinositol-anchored membrane protein CD24 correlates with a poor prognosis for many human cancers, and in experimental tumors can promote metastasis. However, the mechanism by which CD24 contributes to tumor progression remains unclear. Here we report that in MTLy breast cancer cells CD24 interacts with and augments the kinase activity of c-src, a protein strongly implicated in promoting invasion and metastasis. This occurs within and is dependent upon intact lipid rafts. CD24-augmented c-src kinase activity increased formation of focal adhesion complexes, accelerated phosphorylation of FAK and paxillin and consequently enhanced integrin-mediated adhesion. Loss and gain of function approaches showed that c-src activity is necessary and sufficient to mediate the effects of CD24 on integrin-dependent adhesion and cell spreading, as well as on invasion. Together these results indicate that c-src is a CD24-activated mediator that promotes integrin-mediated adhesion and invasion, and suggest a mechanism by which CD24 might contribute to tumor progression through stimulating the activity of c-src or another member of the Src family.