Multiplicity of cerebrospinal fluid functions: New challenges in health and disease

This review integrates eight aspects of cerebrospinal fluid (CSF) circulatory dynamics: formation rate, pressure, flow, volume, turnover rate, composition, recycling and reabsorption. Novel ways to modulate CSF formation emanate from recent analyses of choroid plexus transcription factors (E2F5), ion transporters (NaHCO3 cotransport), transport enzymes (isoforms of carbonic anhydrase), aquaporin 1 regulation, and plasticity of receptors for fluid-regulating neuropeptides. A greater appreciation of CSF pressure (CSFP) is being generated by fresh insights on peptidergic regulatory servomechanisms, the role of dysfunctional ependyma and circumventricular organs in causing congenital hydrocephalus, and the clinical use of algorithms to delineate CSFP waveforms for diagnostic and prognostic utility. Increasing attention focuses on CSF flow: how it impacts cerebral metabolism and hemodynamics, neural stem cell progression in the subventricular zone, and catabolite/peptide clearance from the CNS. The pathophysiological significance of changes in CSF volume is assessed from the respective viewpoints of hemodynamics (choroid plexus blood flow and pulsatility), hydrodynamics (choroidal hypo- and hypersecretion) and neuroendocrine factors (i.e., coordinated regulation by atrial natriuretic peptide, arginine vasopressin and basic fibroblast growth factor). In aging, normal pressure hydrocephalus and Alzheimer's disease, the expanding CSF space reduces the CSF turnover rate, thus compromising the CSF sink action to clear harmful metabolites (e.g., amyloid) from the CNS. Dwindling CSF dynamics greatly harms the interstitial environment of neurons. Accordingly the altered CSF composition in neurodegenerative diseases and senescence, because of adverse effects on neural processes and cognition, needs more effective clinical management. CSF recycling between subarachnoid space, brain and ventricles promotes interstitial fluid (ISF) convection with both trophic and excretory benefits. Finally, CSF reabsorption via multiple pathways (olfactory and spinal arachnoidal bulk flow) is likely complemented by fluid clearance across capillary walls (aquaporin 4) and arachnoid villi when CSFP and fluid retention are markedly elevated. A model is presented that links CSF and ISF homeostasis to coordinated fluxes of water and solutes at both the blood-CSF and blood-brain transport interfaces

Logging in: Perceptions of e-mail usage by university students in the Philippines

This study identifies the factors that influence the patterns and perceptions of e-mail usage among students in a Philippine university. The results indicate that the medium appears to be used primarily for social, rather than academic, purposes. The age of e-mail accounts, frequency and length of log-ins were found to be significantly related to students\u27 e-mail use. The analysis of perceptions of media appropriateness for various communication activities indicate some support for the hierarchy suggested by social presence and media richness theories. Email was highly ranked for exchanging information and for staying in touch. Novelty, access, and faculty issues related to using e-mail as a tool for discussion and feedback are discussed

Structural characterisation of the acyl CoA Diacylglycerol acyltransferase 1 (DGAT1) gene and association studies with milk traits in Assaf sheep breed

Because DGAT1 plays a fundamental role in triacylglycerol synthesis, existing SNPs in DGAT1 gene might provide important information in partially explaining, the variation of milk fat content in dairy sheep. Therefore, the main objective of this study was to sequence the complete ovine acyl CoAdiacylglycerol acyltransferase 1 (DGAT1)gene in order to identify polymorphisms and to look for its possible association with milk traits in Assaf sheep breed. Polymorphisms identification in the DGAT1gene was carried out in 50 individuals belonging to five sheep breeds reared in Spain Rasa Aragonesa (n=10), Manchega (n=10), Churra Tensina (n=10), Latxa (n=10) and Spanish Assaf (n=10). The association studies between polymorphisms, and milk traits were carried out using animals belonging to three flocks of Assaf breed (n=402). Four SNPs were detected, one in exon 1 (EU178818 g.358C>A), two in exon 17 (g.8522C>T and g.8539C>T), and one in intron 10 (g.7457C>A). The SNP in exon 1, g.358C>A, generates a non-conservative substitution at position p. Asp53Glu (GenBank ABW24130). The first SNP in exon 17 (g.8522C>T)causes an amino acid change at position p. Arg482Cys. The genotype frequencies were studied in a panel of 9 breed reared in Spain Ansotana (n=50), Latxa (n=36), Romanov (n=33), Rasa aragonesa (n=55), Churra (n=52), Churra tensina (n=57), Churra lebrijana (n=50), Manchega (n=48) and Assaf (n=402). All breeds were in Hardy-Weinberg equilibrium for all SNPs, except for the SNPs g.8522C>T and g.8539C>T SNPs which showed a deficit of heterozygous animals in Ansotana breed. This gene show low variability in a panel of 9 breeds reared in Spain. The only polymorphism not fixed in Assaf breed was the SNP g.8539C>T, and was used to test possible association with milk traits. The allelic frequency of the 8539C allele was 0.96, being 373 animals homozygous for the CC genotype and 29 heterozygous. The association studies showed that lactose, fatty acids C40, C161 c9, and the ratio n-6n-3 were affected by the SNP g.8539C>T. Animals carrying the CC genotype had greater lactose, C4:0 and C16:1 c9 contents and lower ratio of n-6:n-3 compare to the CT ones. Probably the SNP g.8539C>T, is not causative of the variation observed in the lactose content but might be in linkage disequilibrium with the causal mutation located in the same or other closer gene. © 2015 Elsevier B.V. All rights reserved

Young people's beliefs about intergenerational communication - An initial cross-cultural comparison

This article examines young people's perceptions of their conversations with older people (age 65-85) across nine cultures-five Eastern and four Western. Responses from more than 1,000 participants were entered into a cross-national factor analysis, which revealed four initial factors that underlie perceptions of intergenerational conversations. Elder nonaccommodation was when young participants reported that older people negatively stereotyped the young and did not attend to their communication needs. On the other hand, elder accommodation was when older people were perceived as supportive, attentive and generally encouraging to young people. A third factor was respect/obligation and a fourth factor labeled age-irrelevant positivity described a situation where young people felt conversations with much older people were emotionally positive and satisfying, age did not matter: Examining cross-cultural differences, some East versus West differences were observed, as might be expected, on the basis of simplistic accounts of Eastern collectivism versus Western individualism. However the results challenge commonsense notions of the status of old age in Eastern versus Western cultures. On some dimensions, participants from Korea, Japan, People's Republic of China, Hong Kong, and the Philippines appear to have relatively less positive perceptions of their conversations with older people than the Western cultures-the United States, Australia, New Zealand and Canada. But there was also evidence of considerable cultural variability, particularly among Eastern cultures-variability that has heretofore all too often been glossed over when global comparisons of East versus West are made. A range of explanations for these cultural differences is explored and implications for older people in these societies are also considered