Investigation into the significance of task difficulty and divided allocation of resources on the glucose memory facilitation effect

RATIONALE: Memory for a list of 20 words can be enhanced by preceding learning with consumption of 25 g glucose rather than an equally sweet aspartame solution. In previous studies, participants performed a secondary hand-movement task during the list-learning phase. OBJECTIVE: The present placebo-controlled, double-blind study examined whether the additional cognitive load created by a secondary task is a crucial feature of the glucose memory facilitation effect. METHODS: The effect of glucose administration on word recall performance in healthy young participants was examined under conditions where the primary memory task and a secondary task were competing for cognitive resources (across a range of secondary tasks), and where task difficulty was increased but dual task-mediated competition for cognitive resources did not exist. Measures of non-verbal and working memory performance were also compared under the different glycaemic conditions (glucose versus aspartame drinks). RESULTS: In the present study, a beneficial effect of glucose on memory was detected after participants encoded a 20-word list while performing a secondary task, but not when participants encoded the list without a secondary task, nor when the 20 target words were intermixed with 20 non-target words (distinguished by gender of speaker). In addition, glucose significantly enhanced performance on spatial and working memory tasks. CONCLUSION: The data indicate that possible "depletion" of episodic memory capacity and/or glucose-mediated resources in the brain due to performing a concomitant cognitive task might be crucial to the demonstration of a glucose facilitation effect. Possible implications regarding underlying cognitive and physiological mechanisms are discussed in this article.     

Analysis of cytotoxic effects of silver nanoclusters on human peripheral blood mononuclear cells ‘in vitro’

The antimicrobial properties of silver nanoparticles (AgNPs) have made these particles one of the most used nanomaterials in consumer products. Therefore, an understanding of the interactions (unwanted toxicity) between nanoparticles and human cells is of significant interest. The aim of this study was to assess the in vitro cytotoxicity effects of silver nanoclusters (AgNC, < 2 nm diameter) on peripheral blood mononuclear cells (PBMC). Using flow cytometry and comet assay methods, we demonstrate that exposure of PBMC to AgNC induced intracellular reactive oxygen species (ROS) generation, DNA damage and apoptosis at 3, 6 and 12 h, with a dose‐dependent response (0.1, 1, 3, 5 and 30 µg ml^–1). Advanced electron microscopy imaging of complete and ultrathin‐sections of PBMC confirmed the cytotoxic effects and cell damage caused by AgNC. The present study showed that AgNC produced without coating agents induced significant cytotoxic effects on PBMC owing to their high aspect ratio and active surface area, even at much lower concentrations (<1 µg ml^–1) than those applied in previous studies, resembling what would occur under real exposure conditions to nanosilver‐functionalized consumer products. Copyright © 2015 John Wiley & Sons, Ltd.     

Vida PURA: A Cultural Adaptation of Screening and Brief Intervention to Reduce Unhealthy Drinking Among Latino Day Laborers

Background: Brief intervention is known to reduce drinking in primary care; however, because health care access is limited for Latino immigrants, traditional brief interventions are unlikely to reach this population. Methods: Using Barrera and Castro's framework, our study aims to culturally adapt a screening and brief intervention program to reduce unhealthy alcohol use among Latino day laborers, a particularly vulnerable group of Latino immigrant men. We conducted 18 interviews with Latino day laborers and 13 interviews with mental health and substance use providers that serve Latino immigrant men. Interviews were conducted until saturation of themes was reached. Themes from interviews were used to identify sources of mismatch between traditional screening and brief intervention in our target population. Results: Unhealthy alcohol use was common, culturally accepted, and helped relieve immigration-related stressors. Men had limited knowledge about how to change their behavior. Men preferred to receive information from trusted providers in Spanish. Men faced significant barriers to accessing health and social services but were open to receiving brief interventions in community settings. Findings were used to design Vida PURA, a preliminary adaptation design of brief intervention for Latino day laborers. Key adaptations include brief intervention at a day labor worker center provided by promotores trained to incorporate the social and cultural context of drinking for Latino immigrant men. Conclusions: Culturally adapted brief intervention may help reduce unhealthy drinking in this underserved population.     

Chronic gastric ulcer healing in rats subjected to selective and non-selective cyclooxygenase-2 inhibitors

The influence of different nonsteroidal anti-inflammatory drugs (NSAIDs) and of a proton pump inhibitor on the healing parameters of a chronic gastric ulcer was evaluated. Wistar rats were used after the induction of a chronic acetic acid ulcer. The animals were treated orally for 8 and 15 days, twice daily, with the conventional NSAID, piroxicam (0.35 mg/kg), the non-narcotic analgesic, metamizol (33 mg/kg), the selective cyclooxygenase-2 inhibitor, celecoxib (1.8 mg/kg) and the proton pump inhibitor, omeprazole (0.35 mg/kg). Macroscopic ulcer index, myeloperoxidase activity and prostaglandin E(2) content (both biochemical parameters were evaluated in ulcerated and in intact tissue) as well as histological and immunohistochemical evaluations were carried out at 8 and 15 days. Omeprazole accelerated ulcer healing at 8 and 15 days (P<0.05), while celecoxib delayed healing significantly at 15 days (P<0.01). At 8 days, the prostaglandin E2 content decreased with all NSAIDs at the ulcer site as well as in intact tissue. The same happened at 15 days except for celecoxib, which only diminished prostaglandins in intact mucosa. Immunohistochemistry showed differences in the location of cyclooxygenase-2 and -1. The highest cyclooxygenase-2 expression was found with piroxicam and the lowest expression was with celecoxib. CONCLUSIONS: Down-regulation of cyclooxygenase-2 expression as well as a possible involvement of the chemical structure of celecoxib, a 1,5-dirarylpirazole with a sulphonamide moiety, may account for the delay in ulcer healing.     

Prevalence of and factors associated with current asthma symptoms in school children aged 6–7 and 13–14 yr old in Bogotá, Colombia

This cross‐sectional study of children aged 6–7 years and adolescents aged 13–14 years in Bogotá, Colombia, assessed the prevalence of asthma symptoms and their associations with dietary, health, and behavioral habits. This study is part of the International Study of Asthma and Allergies in Childhood (ISAAC)‐phase III. Asthma prevalence among the children was assessed using a parental self‐administered written questionnaire (WQ), and among adolescents using a WQ together with a video questionnaire (VQ). Associations were estimated with bivariate and multivariate analysis. The study found that the 6–7 year age‐group were more likely to report current asthma symptoms than the 13–14 year age‐group (10.4% [WQ] vs. 8.6% [WQ] and 8.0% [VQ], respectively). Factors associated with current asthma symptoms among the 6–7 year age‐group included higher maternal education (OR = 1.7, [95% CI 1.2–2.6], p = 0.007), a cat in the home during the last year (OR = 1.5, [95% CI 1.0–2.3], p = 0.036), watching TV 1–2 hours/day (OR = 2.1, [95% CI 1.2–3.9], p = 0.013), and medication with acetaminophen in the first and most recent year of life (OR = 1.8, [95% CI 1.3–2.4], p < 0.001; OR = 2.2, [95% CI 1.7–2.8], p < 0.001, respectively) or antibiotics in the first year of life (OR = 1.9, [95% CI 1.4–2.5], p < 0.001). Among the 13–14 year age‐group, factors associated with current asthma symptoms included medication with acetaminophen during the last year (OR = 1.8, [95% CI 1.4–2.3], p < 0.001); cereal, milk, and fruit consumption 3 or more times weekly (OR = 1.5, [95% CI 1.1–1.9], p = 0.010; OR = 0.8, [95% CI 0.6–1.0], p = 0.046; OR = 0.6, [95% CI 0.4–1.0], p = 0.031, respectively). Overall, compared with that in other Latin American centers, asthma prevalence in Bogotá is close the lower estimates. However, associations with dietary, health, and behavioral habits need further study to assess their complex relationship with asthma.     

Human ESCs predisposition to karyotypic instability: Is a matter of culture adaptation or differential vulnerability among hESC lines due to inherent properties?

Background  

The use of human embryonic stem cells (hESCs) in research is increasing and hESCs hold the promise for many biological, clinical and toxicological studies. Human ESCs are expected to be chromosomally stable since karyotypic changes represent a pitfall for potential future applications. Recently, several studies have analysed the genomic stability of several hESC lines maintained after prolonged in vitro culture but controversial data has been reported. Here, we prompted to compare the chromosomal stability of three hESC lines maintained in the same laboratory using identical culture conditions and passaging methods.     

Removal and Accumulation of Cadmium and Lead by <Emphasis Type="Italic">Typha latifolia</Emphasis> Exposed to Single and Mixed Metal Solutions

We investigated the effect of Cd and Pb on the growth of the aquatic macrophyte Typha latifolia; the removal from the solution and the accumulation of these elements by the plant were also studied. Thus, small plants of T. latifolia, collected from a noncontaminated site, were exposed for 10 days to Cd and Pb, in a single solution or in mixture solutions, at two concentrations of the metals (5 and 7.5 mg/L). Our results showed that T. latifolia removed effectively Cd and Pb from solutions and was able to accumulate these metals in the roots and, to a lesser extent, in the leaves. Our findings suggested a synergistic effect of Cd and Pb with respect to the toxicity to T. latifolia. Additionally, Cd diminished the Pb absorption by T. latifolia. Our results confirmed, using scanning electron microscopy, the internalization of Cd and Pb in T. latifolia.     

Integration between the cranial boundaries of the nasopharynx and the upper cervical vertebrae in Homo and Pan

The nasopharynx is an important anatomical structure involved in respiration. Its bony boundaries, including the basicranium and upper cervical vertebrae, may be subject to selective pressures and constraints related to respiratory function. Here, we investigate phenotypic integration, or covariation, between the face, the basicranial boundaries of the nasopharynx, and the atlas and axis to understand constraints affecting these structures. We collected three-dimensional coordinate data from a sample of 80 humans and 44 chimpanzees, and used two-block partial least squares to assess RV (a multivariate generalization of Pearson's r²), r_PLS, the covariance ratio, and effect size for integration among structures. We find that integration is significant among some of these structures, and that integration between the basicranial nasopharynx and vertebrae and between the face and vertebrae is likely independent. We also find divergences in the pattern of integration between humans and chimpanzees suggesting greater constraints among the human face and nasopharynx, which we suggest are linked to divergent developmental trajectories in the two taxa. Evolutionary changes in human basicranial anatomy, coupled with human-like developmental trajectories, may have required that the face grow to compensate any variation in nasopharyngeal structure. However, we were unable to determine whether the nasopharynx or the face is more strongly integrated with the vertebrae, and therefore whether respiration or biomechanical considerations related to positional behavior may be more strongly tied to vertebral evolution. Future work should focus on greater sample sizes, soft tissue structures, and more diverse taxa to further clarify these findings.     

Gfap‐positive radial glial cells are an essential progenitor population for later‐born neurons and glia in the zebrafish spinal cord

Radial glial cells are presumptive neural stem cells (NSCs) in the developing nervous system. The direct requirement of radial glia for the generation of a diverse array of neuronal and glial subtypes, however, has not been tested. We employed two novel transgenic zebrafish lines and endogenous markers of NSCs and radial glia to show for the first time that radial glia are essential for neurogenesis during development. By using the gfap promoter to drive expression of nuclear localized mCherry we discerned two distinct radial glial‐derived cell types: a major nestin+/Sox2+ subtype with strong gfap promoter activity and a minor Sox2+ subtype lacking this activity. Fate mapping studies in this line indicate that gfap+ radial glia generate later‐born CoSA interneurons, secondary motorneurons, and oligodendroglia. In another transgenic line using the gfap promoter‐driven expression of the nitroreductase enzyme, we induced cell autonomous ablation of gfap+ radial glia and observed a reduction in their specific derived lineages, but not Blbp+ and Sox2+/gfap‐negative NSCs, which were retained and expanded at later larval stages. Moreover, we provide evidence supporting classical roles of radial glial in axon patterning, blood–brain barrier formation, and locomotion. Our results suggest that gfap+ radial glia represent the major NSC during late neurogenesis for specific lineages, and possess diverse roles to sustain the structure and function of the spinal cord. These new tools will both corroborate the predicted roles of astroglia and reveal novel roles related to development, physiology, and regeneration in the vertebrate nervous system. GLIA 2016;64:1170–1189