853 research outputs found
Evaluation of alternative solvents in common amide coupling reactions : replacement of dichloromethane and N,N-dimethylformamide
A range of alternative solvents have been evaluated within amidation reactions employing common coupling reagents with a view to identifying suitable replacements for dichloromethane and N,N-dimethylformamid
Visual distraction in cytopathology: should we be concerned?
Visual distraction in cytopathology has not been previously investigated as a source of diagnostic error, presumably because the viewing field of a conventional light microscope is considered large enough to minimise interference from peripheral visual stimuli. Virtual microscopy, which involves the examination of digitised images of pathology specimens on computer screens, is beginning to challenge the central role of light microscopy as a diagnostic tool in cytopathology. The relatively narrow visual angle offered by virtual microscopy makes it conceivable that users of these systems are more vulnerable to visual interference.
Using a variant of a visual distraction paradigm (the Eriksen flanker task), the aim of the study was to determine whether the accuracy and speed of interpreting cells on a central target screen is affected by images of cells and text displayed on neighbouring monitors under realistic reading room conditions
Bi-allelic JAM2 Variants Lead to Early-Onset Recessive Primary Familial Brain Calcification.
Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder characterized by a combination of neurological, psychiatric, and cognitive decline associated with calcium deposition on brain imaging. To date, mutations in five genes have been linked to PFBC. However, more than 50% of individuals affected by PFBC have no molecular diagnosis. We report four unrelated families presenting with initial learning difficulties and seizures and later psychiatric symptoms, cerebellar ataxia, extrapyramidal signs, and extensive calcifications on brain imaging. Through a combination of homozygosity mapping and exome sequencing, we mapped this phenotype to chromosome 21q21.3 and identified bi-allelic variants in JAM2. JAM2 encodes for the junctional-adhesion-molecule-2, a key tight-junction protein in blood-brain-barrier permeability. We show that JAM2 variants lead to reduction of JAM2 mRNA expression and absence of JAM2 protein in patient's fibroblasts, consistent with a loss-of-function mechanism. We show that the human phenotype is replicated in the jam2 complete knockout mouse (jam2 KO). Furthermore, neuropathology of jam2 KO mouse showed prominent vacuolation in the cerebral cortex, thalamus, and cerebellum and particularly widespread vacuolation in the midbrain with reactive astrogliosis and neuronal density reduction. The regions of the human brain affected on neuroimaging are similar to the affected brain areas in the myorg PFBC null mouse. Along with JAM3 and OCLN, JAM2 is the third tight-junction gene in which bi-allelic variants are associated with brain calcification, suggesting that defective cell-to-cell adhesion and dysfunction of the movement of solutes through the paracellular spaces in the neurovascular unit is a key mechanism in CNS calcification
How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?
This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1).For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace changes in gene expression during cold acclimation that lead to an increase in cold tolerance. We used an RNA-Seq approach to investigate this in two species of the Drosophila virilis group. We found that the majority of genes that are differentially expressed during cold acclimation differ between the two species. Despite this, the biological processes associated with the differentially expressed genes were broadly similar in the two species. These included: metabolism, cell membrane composition, and circadian rhythms, which are largely consistent with previous work on cold acclimation/cold tolerance. In addition, we also found evidence of the involvement of the rhodopsin pathway in cold acclimation, a pathway that has been recently linked to thermotaxis. Interestingly, we found no evidence of differential expression of stress genes implying that long-term cold acclimation and short-term stress response may have a different physiological basis.PostprintPeer reviewe
Contemporary Pastoralism in the Dhofar Mountains of Oman
In the Dhofar Mountains of Oman stakeholders are concerned about the social and ecological sustainability of pastoralism. In this study we used interviews with pastoralists to examine the prevailing drivers of pastoralism and how they are changing. We find that people are committed to pastoralism for sociocultural reasons, but also that this commitment is under pressure because of husbandry costs and changing values. We find that capital investment in feedstuff enables pastoralists to overcome the density-dependent regulation of livestock populations. However, high production costs deter investment in marketing and commercialization, and there is little offtake of local livestock. Our study reveals how pastoral values, passed down within households, motivate pastoralism in the face of high husbandry costs, modernization and social change
Differential effects of Atomoxetine on executive functioning and lexical decision in Attention-Deficit/Hyperactivity Disorder and Reading Disorder
Objective: The effects of a promising pharmacological treatment for attention-deficit/hyperactivity disorder (ADHD), atomoxetine, were studied on executive functions in both ADHD and reading disorder (RD) because earlier research demonstrated an overlap in executive functioning deficits in both disorders. In addition, the effects of atomoxetine were explored on lexical decision.
Methods: Sixteen children with ADHD, 20 children with ADHD + RD, 21 children with RD, and 26 normal controls were enrolled in a randomized placebo-controlled crossover study. Children were measured on visuospatial working memory, inhibition, and lexical decision on the day of randomization and following two 28-day medication periods.
Results: Children with ADHD + RD showed improved visuospatial working memory performance and, to a lesser extent, improved inhibition following atomoxetine treatment compared to placebo. No differential effects of atomoxetine were found for lexical decision in comparison to placebo. In addition, no effects of atomoxetine were demonstrated in the ADHD and RD groups.
Conclusion: Atomoxetine improved visuospatial working memory and to a lesser degree inhibition in children with ADHD + RD, which suggests differential developmental pathways for co-morbid ADHD + RD as compared to ADHD and RD alone
Disparities in Healthcare Utilisation Rates for Aboriginal and Non-Aboriginal Albertan Residents, 1997-2006: A Population Database Study
Background: It is widely recognised that significant discrepancies exist between the health of indigenous and nonindigenous
populations. Whilst the reasons are incompletely defined, one potential cause is that indigenous communities
do not access healthcare to the same extent. We investigated healthcare utilisation rates in the Canadian Aboriginal
population to elucidate the contribution of this fundamental social determinant for health to such disparities.
Methods: Healthcare utilisation data over a nine-year period were analysed for a cohort of nearly two million individuals to
determine the rates at which Aboriginal and non-Aboriginal populations utilised two specialties (Cardiology and
Ophthalmology) in Alberta, Canada. Unadjusted and adjusted healthcare utilisation rates obtained by mixed linear and
Poisson regressions, respectively, were compared amongst three population groups - federally registered Aboriginals,
individuals receiving welfare, and other Albertans.
Results: Healthcare utilisation rates for Aboriginals were substantially lower than those of non-Aboriginals and welfare
recipients at each time point and subspecialty studied [e.g. During 2005/06, unadjusted Cardiology utilisation rates were
0.28% (Aboriginal, n = 97,080), 0.93% (non-Aboriginal, n = 1,720,041) and 1.37% (Welfare, n = 52,514), p = ,0.001]. The age
distribution of the Aboriginal population was markedly different [2.7%$65 years of age, non-Aboriginal 10.7%], and
comparable utilisation rates were obtained after adjustment for fiscal year and estimated life expectancy [Cardiology:
Incidence Rate Ratio 0.66, Ophthalmology: IRR 0.85].
Discussion: The analysis revealed that Aboriginal people utilised subspecialty healthcare at a consistently lower rate than
either comparatively economically disadvantaged groups or the general population. Notably, the differences were relatively
invariant between the major provincial centres and over a nine year period. Addressing the causes of these discrepancies is
essential for reducing marked health disparities, and so improving the health of Aboriginal people
Different Modes of Retrovirus Restriction by Human APOBEC3A and APOBEC3G In Vivo
The apolipoprotein B editing complex 3 (A3) cytidine deaminases are among the most highly evolutionarily selected retroviral restriction factors, both in terms of gene copy number and sequence diversity. Primate genomes encode seven A3 genes, and while A3F and 3G are widely recognized as important in the restriction of HIV, the role of the other genes, particularly A3A, is not as clear. Indeed, since human cells can express multiple A3 genes, and because of the lack of an experimentally tractable model, it is difficult to dissect the individual contribution of each gene to virus restriction in vivo. To overcome this problem, we generated human A3A and A3G transgenic mice on a mouse A3 knockout background. Using these mice, we demonstrate that both A3A and A3G restrict infection by murine retroviruses but by different mechanisms: A3G was packaged into virions and caused extensive deamination of the retrovirus genomes while A3A was not packaged and instead restricted infection when expressed in target cells. Additionally, we show that a murine leukemia virus engineered to express HIV Vif overcame the A3G-mediated restriction, thereby creating a novel model for studying the interaction between these proteins. We have thus developed an in vivo system for understanding how human A3 proteins use different modes of restriction, as well as a means for testing therapies that disrupt HIV Vif-A3G interactions.United States. Public Health Service (Grant R01-AI-085015)United States. Public Health Service (Grant T32-CA115299 )United States. Public Health Service (Grant F32-AI100512
Two antagonistic response regulators control Pseudomonas aeruginosa polarization during mechanotaxis.
The opportunistic pathogen Pseudomonas aeruginosa adapts to solid surfaces to enhance virulence and infect its host. Type IV pili (T4P), long and thin filaments that power surface-specific twitching motility, allow single cells to sense surfaces and control their direction of movement. T4P distribution is polarized to the sensing pole by the chemotaxis-like Chp system via a local positive feedback loop. However, how the initial spatially resolved mechanical signal is translated into T4P polarity is incompletely understood. Here, we demonstrate that the two Chp response regulators PilG and PilH enable dynamic cell polarization by antagonistically regulating T4P extension. By precisely quantifying the localization of fluorescent protein fusions, we show that phosphorylation of PilG by the histidine kinase ChpA controls PilG polarization. Although PilH is not strictly required for twitching reversals, it becomes activated upon phosphorylation and breaks the local positive feedback mechanism established by PilG, allowing forward-twitching cells to reverse. Chp thus uses a main output response regulator, PilG, to resolve mechanical signals in space and employs a second regulator, PilH, to break and respond when the signal changes. By identifying the molecular functions of two response regulators that dynamically control cell polarization, our work provides a rationale for the diversity of architectures often found in non-canonical chemotaxis systems
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