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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]

Background and design: In this study, we aimed to identify whether there was an association of insulin resistance and metabolic syndrome with androgenetic alopecia (AGA) in reproductive women. Materials and methods: We investigated insulin resistance and metabolic syndrome, which is known to be associated with insulin-resistance, in 55 females with AGA (Ludwig I and above) who were under 45 years of age and 50 age-matched woman without AGA. We used homeostasis model assessment (HOMA) index and quantitative insulin sensitivity check index (QUICKI) to identify insulin resistance. The cut-off value for HOMA was accepted as 2.7. The diagnosis of metabolic syndrome was established using the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria. Results: Serum fasting blood glucose levels were significantly higher in females with AGA than in controls (p<0.05). According to HOMA index, insulin resistance was determined in 11 of 55 (20%) patients in the AGA group, whereas it was identified in only 6 of 50 (12%) controls. The difference between the two groups was not statistically significant (p>0.05). The two groups were also compared for the levels of QUICKI. The mean levels of QUICKI in patient control groups were 0.36±0.04 and 0.36±0.03, respectively. The difference between the groups was not statistically significant (p>0.05). Finally, when the two groups were assessed according to the NCEP ATP III-criteria, metabolic syndrome was identified in 5 out of the 55 (9.1%) patients in the AGA group whereas none of participants had metabolic syndrome in control group. The difference between these groups was not statistically significant (p>0.05). Conclusion: In our study, it was shown that there was no significant relationship of insulin resistance and metabolic syndrome with AGA in women. (Turkderm 2015; 49: 134-8) [ABSTRACT FROM AUTHOR]

A hair follicle is the primary unit that produces a single outgrowing visible hair shaft. All hair follicles have a regeneration cycle consisting growth, destruction and resting phase, all of which are controlled by several intrinsic and extrinsic mechanisms. All hair forming cell populations arise from hair follicle stem cells that are located in bulge and hair germ. Epithelial progenitors themselves surround a core cluster of mesenchymal cells, the dermal papilla, which is thought to provide signals to coordinate hair growth. The exchange of molecular cues between epithelial and mesenchymal compartments begins during embryogenesis, when hair follicles are first formed. After initial hair follicle formation and a prolonged period of growth, follicles undergo cycles of destruction and regeneration throughout life. For new hair re-growth, signal exchange between dermal papilla cells and stem/progenitor cells is thought to occur in a process that is reminiscent of embryonic hair follicle formation. Many diverse developmental programs require coordinated mesenchymal-epithelial interactions for completion, and studies of hair growth provide an exquisite system in which to study the complexities of this universally important process. The purpose of this mini review is to provide a short glance at the growth cycle of the hair and to present the conceptual data regarding the hair homeostasis. [ABSTRACT FROM AUTHOR]

A hair follicle is the primary unit that produces a single outgrowing visible hair shaft. All hair follicles have a regeneration cycle consisting growth, destruction and resting phase, all of which are controlled by several intrinsic and extrinsic mechanisms. All hair forming cell populations arise from hair follicle stem cells that are located in bulge and hair germ. Epithelial progenitors themselves surround a core cluster of mesenchymal cells, the dermal papilla, which is thought to provide signals to coordinate hair growth. The exchange of molecular cues between epithelial and mesenchymal compartments begins during embryogenesis, when hair follicles are first formed. After initial hair follicle formation and a prolonged period of growth, follicles undergo cycles of destruction and regeneration throughout life. For new hair re-growth, signal exchange between dermal papilla cells and stem/progenitor cells is thought to occur in a process that is reminiscent of embryonic hair follicle formation. Many diverse developmental programs require coordinated mesenchymal-epithelial interactions for completion, and studies of hair growth provide an exquisite system in which to study the complexities of this universally important process. The purpose of this mini review is to provide a short glance at the growth cycle of the hair and to present the conceptual data regarding the hair homeostasis. [ABSTRACT FROM AUTHOR]

Insulin resistance can be broadly defined as a subnormal biological response to endogenous or exogenous insulin. This definition may pertain to many biological actions of insulin in many tissues of the body. Insulin is essential for normal growth and development; and for normal homeostasis of glucose, fat and protein metabolism. Understanding the signaling patways involved in insülin action could lead to a beter understanding of the pathophysiology of insulin resistance associated with type 2 diabetes and metabolic syndrome, and the development of cardiovascular diseases. Insulin resistance has an important role in the pathogenesis of the type 2 diabetes. Insulin resistance has been shown to be associated with prevalent atherosclerosis and endothelial dysfunction. Thus the recognition of insulin resistance seems to have clinical relevance in identifying subjects at high risk for type 2 diabetes and/ or cardiovascular disease. Understanding the signaling pathways involved in insulin action could lead to a better understanding of the pathophysiology of insulin resistance associated with type 2 diabetes and metabolic syndrome, and cardiovascular diseases. [ABSTRACT FROM AUTHOR]