Melatonin is a neurohormone secreted mainly by the pineal gland that controls circadian rhythm, which is primarily regulated by light. Although melatonin levels are known to be altered in individuals with sleep disorders, melatonin also has modulatory effects on other body systems, including the skeletal and immune systems. In addition, melatonin has been shown to interfere with carbohydrate and lipid metabolism and to have significant antioxidant effects, both directly and via its metabolites. Melatonin levels vary throughout human life and are known to decrease with age but the effects of declining melatonin levels are poorly understood. In women, this age-related decrease in melatonin levels coincides with the menopause. This review aims to summarize the impact of altered melatonin levels in aging women and the outcomes of exogenous replacement therapies.
P-wave duration is prolonged in the second trimester, and resumes a plateau thereafter. Maximum QTc interval, Tp-e interval and Tp-e/QT ratio are increased in the late pregnancy. Although these indices are altered during the course of pregnancy, they all remain in the normal ranges.
Abstract:Objective: C-reactive protein (CRP) is a well-known marker of infl ammation and infection in clinical practice. This study is designed to evaluate CRP levels in diff erent phases of menstrual cycle, which might end up with misleading conclusions especially when used for cardiovascular risk assessment. Methods: Twenty-seven women were eligible for the cross-sectional study. Venous blood samples from each participant were collected twice during the menstrual cycle. The fi rst sampling was held at 2nd to 5th days of the menstrual cycle for FSH, estradiol, CRP, and sedimentation, and the second was done at 21st to 24th days of the menstrual cycle for measurement of progesterone, CRP, and sedimentation values. Results: CRP values were signifi cantly higher in the early follicular phase compared to luteal phase (1.8 mg/L [0.3-7.67] vs. 0.7 mg/L [0.1-8.3], p < 0.001, respectively). In both phases of the menstrual cycle, sedimentation rate was similar (12.1 ± 6.7 vs. 12.3 ± 7.7; p = 0.717, respectively). Conclusions: CRP levels in early follicular phase of the menstrual cycle (menstruation) are signifi cantly higher than CRP levels in luteal phase of the same cycle. In reproductive age women, detection of CRP for cardiovascular risk assessment during menstruation might not be appropriate.
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