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Sleep and wakefulness are multifactorial, complex and well-regulated physiological processes that occur in all living things. Environmental and genetic factors that affect sleep and wakefulness can change the cycle determined by the circadian rhythm and the duration and intensity of daily brain activity. Considering the necessity of good sleep for health, it is clear that defining the factors that regulate the spontaneous sleepwake cycle is important for the prevention, diagnosis and treatment of many sleep disorders. The facts that the extracellular concentration of adenosine which is defined as an endogenous sleep factor increases during long-term wakefulness, especially in the cortex and basal forebrain, and decreases during sleep, and in addition, caffeine, which is frequently consumed in daily life, acts via this molecule, indicate that it is a molecule that should be considered in the homeostasis of sleep. In this review, studies examining the regulation of the sequential sleepwake cycle and the role of adenosine in this regulation are summarized. [ABSTRACT FROM AUTHOR]

Aim: To determine the relationship of leptin with vitamin D and parathormone (PTH) levels in postmenopausal women who have no osteoporosis and to evaluate the effect of these three parameters on bone mineral dansity and bone homeostasis. Methods: Sixty-eight postmenopausal patients with no osteoporosis, who attended the general internal medicine, geriatric and endocrinology outpatient clinics between November 2013 and June 2014, were included in the study. The patients were divided into two groups according to vitamin D levels. Results: Group 1 consisted of 27 patients with low vitamin D levels and group 2 consisted of 41 patients with normal vitamin D levels. Two groups were similar in terms of age, age of menopause and body mass index (BMI). The mean PTH level and the mean leptin level in group 1 were statistically significantly higher than in group 2 (p= 0.01; p=0.01, respectively). There was no significant correlation between leptin and PTH in group 1 (r=0.16, p=0.4), however, a positive correlation was observed in group 2 (r=0.46, p=0.002). We found a significant positive correlation between leptin and BMI in both groups (r=0.40, p< 0.01). No significant correlation was found between leptin and vitamin D in both groups. Conclusion: In our study, the high leptin levels in postmenapasaul women having low vitamin D levels without osteoporosis or obesity may suggest the role of leptin in the prevention of osteoporosis. [ABSTRACT FROM AUTHOR]

Sleep is a physiologically active process and the function of cognitive processes is known for a long time. It is also known that sleep has a crucial role in two distinct phases of memory. The first one is the information encoding phase which is prior to the learning process; and the second one is the consolidation phase which is related with the persistency of new information after learning occurs. Consolidation is thought as a function of evolutionarily preserved sleep for many forms of memory. The aim of this review is to get together the main study findings which investigating the relationship between the micro and macro structures of sleep and declarative memory processes. Firstly, definition of sleep is given, and then the specific role of sleep in declarative memory consolidation process is explained. In this context, the projected active system consolidation and synaptic homeostasis hypothesis are explicated. The study results investigating the effects of sleep deprivation on declarative memory and information processing phases are summarized. Finally, the role of sleep spindle and slow wave activity on memory processes, which make up the microstructure of sleep, is discussed. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of continuous positive airway pressure (CPAP) treatment on metabolic syndrome and insuline resistance in patients with obstructive sleep apnea syndrome (OSAS). Materials and Methods: This study evaluated retrospectively with 30 patients who received OSAS diagnosis following polysomnography between the years January 2016 - January 2017, whose Respiratory Disturbance Index were above 15, and who were between the ages of 18-78, having no diabetes, chronic liver and kidney disease, malignancy and mental retardation. The anthropometric measures and blood values of these patients before the CPAP treatment and 3 months afterwards were evaluated in their controls. The effect of CPAP treatment on metabolic syndrome and insulin resistance assessed by homeostatic model assessment index was investigated Results: It has been observed that the body mass index (BMI) decreases significantly following the CPAP treatment. No significant changes were found in the anthropometric measurements including the neck circumference, waist circumference, hip circumference, and waist/hip ratios as well as insulin resistance and metabolic syndrome parameters (before of treatment BMI: 31.33±5.58, post treatment BMI: 30.83±7.13, p=0.03). The ESS evaluating the subjective daytime sleepiness following the CPAP treatment has decreased significantly. Conclusion: Although this study didn't improve insulin resistance with assessed homeostatic model assessment, and metabolic syndrome, a significant improvement in BMI and ESS was demonstrated in post treatment. Long-term studies with more cases and with high compliance are needed to demonstrate the effects of CPAP treatment on metabolic syndrome in OSAS patients. [ABSTRACT FROM AUTHOR]