Shared genetic mechanisms underlying association between sleep disturbances and depressive symptoms.

OBJECTIVES: Polygenic scores (PGS) for sleep disturbances and depressive symptoms in an epidemiological cohort were contrasted. The overlap between genes assigned to variants that compose the PGS predictions was tested to explore the shared genetic bases of sleep problems and depressive symptoms. METHODS: PGS analysis was performed on the São Paulo Epidemiologic Sleep Study (EPISONO, N = 1042), an adult epidemiological sample. A genome wide association study (GWAS) for depression grounded the PGS calculations for Beck Depression Index (BDI), while insomnia GWAS based the PGS for Insomnia Severity Index (ISI) and Pittsburg Sleep Quality Index (PSQI). Pearson's correlation was applied to contrast PGS and clinical scores. Fisher's Exact and Benjamin-Hochberg tests were used to verify the overlaps between PGS-associated genes and the pathways enriched among their intersections. RESULTS: All PGS models were significant when individuals were divided as cases or controls according to BDI (R2 = 1.2%, p = 0.00026), PSQI (R2 = 3.3%, p = 0.007) and ISI (R2 = 3.4%, p = 0.021) scales. When clinical scales were used as continuous variables, the PGS models for BDI (R2 = 1.5%, p = 0.0004) and PSQI scores (R2 = 3.3%, p = 0.0057) reached statistical significance. PSQI and BDI scores were correlated, and the same observation was applied to their PGS. Genes assigned to variants that compose the best-fit PGS predictions for sleep quality and depressive symptoms were significantly overlapped. Pathways enriched among the intersect genes are related to synapse function. CONCLUSIONS: The genetic bases of sleep quality and depressive symptoms are correlated; their implicated genes are significantly overlapped and converge on neural pathways. This data suggests that sleep complaints accompanying depressive symptoms are not secondary issues, but part of the core mental illness.

Standardization for obtaining blood viscosity: A systematic review.

INTRODUCTION: There is evidence to suggest that blood viscosity (BV) is involved in several pathological processes. In this review, we evaluated the different methods of BV acquisition, analyzing the sample storage time, the storage temperature, the acquisition time, the acquisition temperature, sample volume, and shear rates, in order to standardize this technique. METHODS: We selected 50 articles with methods of obtaining BV, evaluating pathologies through BV, comparing rheological equipment, monitoring, and regulating BV. RESULTS AND CONCLUSION: Measurements should be obtained as soon as possible, to reduce hemorheological changes. It is necessary to refrigerate them at 4°C when the storage time is long. The acquisition time is related to the equipment used. BV measurements at 37°C will represent the real BV in vivo more faithfully. In order to understand the BV phenomena, the shear rates must be between 0.1 and 1000 s-1. There is a wide variety of equipment available for measuring the BV.

Rate of cognitive decline in relation to sex after 60 years-of-age: a systematic review.

Some studies have shown differences in specific cognitive ability domains between the sexes at 60 years-of-age. However is important to analyze whether the rate of cognitive decline is also similar between the sexes after this age. The present study examined previously published literature to investigate whether cognitive decline is distinct between men and women after the age of 60 years. A systematic review was carried out with the PubMed, LILACS and PsycINFO databases (2001-2011) using the following search terms: aging, aged, cognitive function, mild cognitive impairment, mental health and cognition. We analyzed longitudinal research that used neuropsychological tests for evaluating cognitive function, showed results separated by sex and that excluded participants with dementia. Elderly women showed better performance in tests of episodic memory, whereas elderly men had a better visuospatial ability. Only one study detected distinct rates of cognitive decline in specific tests between the sexes. Despite differences observed in some domains, most of the studies showed that this rate is similar between the sexes until the age of 80 years. It is unclear whether sex influences the rate of cognitive decline after the age of 80 years. The present review observed that sex does not determine the rate of cognitive decline between 60 and 80 years-of-age. The contextual and cultural factors that involve men and women might determine a distinct decline between them, rather than sex alone.

The effects of long-term administration of guarana on the cognition of normal, elderly volunteers

Paulina cupana (guarana) is a Brazilian plant given great prestige in popular medicine, for example as being a potent stimulator of brain functions. The authors assessed the effects of the long-term administration of guarana on the cognition of normal, elderly volunteers. Forty-five volunteers were studied, with a randon distribution in three experimental groups: placebo (n=15), caffeine (n=15), and guarana (n=15), in a double-blind study. There were no significant cognitive alterations in these volunteers.