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Search Results: 1 - 10 of 183192 matches for " Mark E Viney "
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Immunological Responses Elicited by Different Infection Regimes with Strongyloides ratti
Steve Paterson, Clare Wilkes, Colin Bleay, Mark E. Viney
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002509
Abstract: Nematode infections are a ubiquitous feature of vertebrate life. In nature, such nematode infections are acquired by continued exposure to infective stages over a prolonged period of time. By contrast, experimental laboratory infections are typically induced by the administration of a single (and often large) dose of infective stages. Previous work has shown that the size of an infection dose can have significant effects on anti-nematode immune responses. Here we investigated the effect of different infection regimes of Strongyloides ratti, comparing single and repeated dose infections, on the host immune response that was elicited. We considered and compared infections of the same size, but administered in different ways. We considered infection size in two ways: the maximum dose of worms administered and the cumulative worm exposure time. We found that both infection regimes resulted in Th2-type immune response, characterised by IL4 and IL13 produced by S. ratti stimulated mesenteric lymph node cells, anti-S. ratti IgG1 and intestinal rat mast cell protease II (RMCPII) production. We observed some small quantitative immunological differences between different infection regimes, in which the concentration of IL4, IL13, anti-S. ratti IgG1 and IgG2a and RMCPII were affected. However, these differences were quantitatively relatively modest compared with the temporal dynamics of the anti-S. ratti immune response as a whole.
Quantitative genetic analysis of life-history traits of Caenorhabditis elegans in stressful environments
Simon C Harvey, Alison Shorto, Mark E Viney
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-15
Abstract: We found that lines of C. elegans vary in their phenotypic plasticity of dauer larva development, i.e. there is variation in the likelihood of developing into a dauer larva for the same environmental change. There was also variation in how lifetime fecundity and the rate of reproduction changed under conditions of environmental stress. These traits were related, such that lines that are highly plastic for dauer larva development also maintain a high population growth rate when stressed. We identified quantitative trait loci (QTL) on two chromosomes that control the dauer larva development and population size phenotypes. The QTLs affecting the dauer larva development and population size phenotypes on chromosome II are closely linked, but are genetically separable. This chromosome II QTL controlling dauer larva development does not encompass any loci previously identified to control dauer larva development. This chromosome II region contains many predicted 7-transmembrane receptors. Such proteins are often involved in information transduction, which is clearly relevant to the control of dauer larva development.C. elegans alters both its larval development and adult reproductive strategy in response to environmental stress. Together the phenotypic and genotypic data suggest that these two major life-history traits are co-ordinated responses to environmental stress and that they are, at least in part, controlled by the same genomic regions.Organisms live in environments that vary both spatially and temporally. In such variable environments there are different ways to maximise fitness. Life-history traits can either be robust to environmental change (a buffered or canalised trait) or they can be variable in an environmentally-dependent manner (a phenotypically plastic trait). Phenotypic plasticity of a trait can be manifest as a continuous phenotypic range across an environmental gradient, such as the variation in Drosophila melanogaster body size metrics across temperat
Quantitative genetic analysis of life-history traits of Caenorhabditis elegans in stressful environments
Simon C Harvey, Alison Shorto, Mark E Viney
BMC Evolutionary Biology , 2009, DOI: 10.1186/1471-2148-9-96
Abstract: In Figure 1 of [1] the plotted data were inverted. The correct Figure is shown below. The text and statistical analyses in [1] are correct.
Natural variation in gene expression in the early development of dauer larvae of Caenorhabditis elegans
Simon C Harvey, Gary LA Barker, Alison Shorto, Mark E Viney
BMC Genomics , 2009, DOI: 10.1186/1471-2164-10-325
Abstract: There were substantial transcriptional differences between four C. elegans lines under the same environmental conditions. The expression of approximately 2,000 genes differed between genetically different lines, with each line showing a largely line-specific transcriptional profile. The expression of genes that are markers of larval moulting suggested that the lines may be developing at different rates. The expression of a total of 89 genes was putatively affected by dauer larva or non-dauer larva-inducing conditions. Among the upstream regions of these genes there was an over-representation of DAF-16-binding motifs.Under the same environmental conditions genetically different lines of C. elegans had substantial transcriptional differences. This variation may be due to differences in the developmental rates of the lines. Different environmental conditions had a rather smaller effect on transcription. The preponderance of DAF-16-binding motifs upstream of these genes was consistent with these genes playing a key role in the decision between development into dauer or into non-dauer larvae. There was little overlap between the genes whose expression was affected by environmental conditions and previously identified loci involved in the plasticity of dauer larva development.Developmental decisions and processes can be controlled transcriptionally. The free-living nematode Caenorhabditis elegans makes a developmental decision between different larval fates. This decision is based on the 'suitability' of the environment for growth and reproduction. Under 'favourable' conditions, second stage larvae (L2) develop via two larval stages (L3, L4) into reproductive adults [1,2]. However, under 'unfavourable' conditions, L2s form a developmentally arrested L3 stage, the so-called dauer larva. Dauer larvae are environmentally resistant, have a specialised metabolism and are comparatively long-lived [2]. Overall, dauer larvae are transcriptionally repressed compared with actively
A microarray analysis of gene expression in the free-living stages of the parasitic nematode Strongyloides ratti
Fiona J Thompson, Gary LA Barker, Louise Hughes, Clare P Wilkes, Jane Coghill, Mark E Viney
BMC Genomics , 2006, DOI: 10.1186/1471-2164-7-157
Abstract: We have constructed an S. ratti cDNA microarray and used it to interrogate changes in gene expression during the free-living phase of the S. ratti life-cycle. We have found very extensive differences in gene expression between first-stage larvae (L1) passed in faeces and infective L3s preparing to infect hosts. In L1 stages there was comparatively greater expression of genes involved in growth. We have also compared gene expression in L2 stages destined to develop directly into infective L3s with those destined to develop indirectly into free-living adults. This revealed relatively small differences in gene expression. We find little evidence for the conservation of transcription profiles between S. ratti and S. stercoralis or C. elegans.This is the first multi-gene study of gene expression in S. ratti. This has shown that robust data can be generated, with consistent measures of expression within computationally determined clusters and contigs. We find inconsistencies between EST representation data and microarray hybridization data in the identification of genes with stage-specific expression and highly expressed genes. Many of the genes whose expression is significantly different between L1 and iL3s stages are unknown beyond alignments to predicted genes. This highlights the forthcoming challenge in actually determining the role of these genes in the life of S. ratti.Parasitic nematodes have complex life-cycles that are affected and controlled by factors both within and outwith their hosts. In the genus Strongyloides, the life-cycle, unusually, includes both an obligate female-only parasitic generation and a facultative dioecious adult free-living generation. In recent years there has been an increasingly detailed understanding of the factors that affect the development of the free-living phase of this life-cycle, particularly for the parasites of rats, S. ratti [1].S. ratti parasitic females lie embedded in the mucosa of the small intestine of their host. These
Comparison of the Distal Gut Microbiota from People and Animals in Africa
Richard J. Ellis, Kenneth D. Bruce, Claire Jenkins, J. Russell Stothard, Lilly Ajarova, Lawrence Mugisha, Mark E. Viney
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054783
Abstract: The gut microbiota plays a key role in the maintenance of healthy gut function as well as many other aspects of health. High-throughput sequence analyses have revealed the composition of the gut microbiota, showing that there is a core signature to the human gut microbiota, as well as variation in its composition between people. The gut microbiota of animals is also being investigated. We are interested in the relationship between bacterial taxa of the human gut microbiota and those in the gut microbiota of domestic and semi-wild animals. While it is clear that some human gut bacterial pathogens come from animals (showing that human – animal transmission occurs), the extent to which the usually non-pathogenic commensal taxa are shared between humans and animals has not been explored. To investigate this we compared the distal gut microbiota of humans, cattle and semi-captive chimpanzees in communities that are geographically sympatric in Uganda. The gut microbiotas of these three host species could be distinguished by the different proportions of bacterial taxa present. We defined multiple operational taxonomic units (OTUs) by sequence similarity and found evidence that some OTUs were common between human, cattle and chimpanzees, with the largest number of shared OTUs occurring between chimpanzees and humans, as might be expected with their close physiological similarity. These results show the potential for the sharing of usually commensal bacterial taxa between humans and other animals. This suggests that further investigation of this phenomenon is needed to fully understand how it drives the composition of human and animal gut microbiotas.
Understanding the individual with Alzheimer’s disease: Can socioemotional selectivity theory guide us?  [PDF]
Ruth E. Mark
Advances in Alzheimer's Disease (AAD) , 2012, DOI: 10.4236/aad.2012.13010
Abstract: Individuals often get lost behind the diagnosis of Alzheimer’s disease (AD) while widespread differences between these patients are morecommon than similarities. Socioemotional Selectivity Theory (SST) suggests that as we age our goals change from future-oriented (acquiringnew information) to present-oriented (enhancing the emotional, especially positive, meaning of encounters). The goal of the current article is to examine whether the principles of SST might also apply for people with AD. Some aspects of SST are found especially in the early stages of AD when awareness is often intact and cognitive impairment is relatively limited. This review has clinical significance for the treatment of AD because it focuses on what is important to the individual rather than treating patients as a homogenous group. It also highlights the importance of social networks and emphasizes the role of the proxy in AD care. Lastly, it suggests that if those with AD (like the healthy elderly) have a positivity bias then positive emotional stimuli/wording/instructions could usefully be employed in their daily treatment. I suggest that SST may be a useful starting point when attempting to address what matters to individuals with AD and conclude by providing a few suggestions for future studies.
What Is “African Bioethics” as Used by Sub-Saharan African Authors: An Argumentative Literature Review of Articles on African Bioethics  [PDF]
Albert Mark E. Coleman
Open Journal of Philosophy (OJPP) , 2017, DOI: 10.4236/ojpp.2017.71003
The term “African bioethics” is more often used by some Sub-Saharan African (SSA) authors to denote an African framework of resolving pertinent moral dilemmas arising in the interface of human persons with biomedical sciences, as juxtaposed against what is deemed “Western bioethics paradigms/theories, considered otherwise as a form of “moral/ethical imperialism”; and considered foreign to SSA tradition(s). This article is a literature review of articles on African bioethics to clarify what actually is meant epistemologically by African bioethics vis a vis, Western bioethics, as well as ascertain whether African bioethics as used by SSA authors is wishful thinking, yet to be realised in actuality.
Contact trans-scleral laser cyclophotocoagulation treatment for refractory glaucomas in the Indian population
Gupta Viney,Agarwal Harish
Indian Journal of Ophthalmology , 2000,
Abstract: Purpose: This study aimed to evaluate the clinical efficacy of contact diode trans-scleral cyclophotocoagulation (TSCPC) for treatment of refractory glaucomas. Method: Fifty two eyes of 52 patients, (post-penetrating keratoplasty glaucoma: 16 eyes; adherent leucoma with secondary glaucoma: 8 eyes; aphakic glaucoma: 6 eyes; neovascular glaucoma: 6 eyes; narrow angle glaucoma: 6 eyes; and other secondary glaucomas: 10 eyes) were followed up from 3.5 -18 months (average 12 months) after TSCPC. The treatment parameters using the contact G probe were - energy: 3-4J; area: 40 spots spread over 360°; site: 1.2-1.5 mm posterior to limbus. Retreatments (22 eyes; 42%) were given whenever intraocular pressure (IOP) exceeded 22 mmHg despite maximum tolerable topical therapy. Results: IOP decreased from a baseline of 44.7 (± 7.3) mmHg to 15 (± 3.7) mmHg at first week and was 15.2 ± (8.2) mmHg at the last follow up. Successful control of IOP (<22mmHg) occurred in 30 (58%) eyes after a single treatment and in 48 (92%) eyes following retreatment. Complications included reduction in visual acuity from light perception (LP) only to no light perception (NLP) in two eyes and phthisis bulbi in one eye. Conclusion: Contact trans-scleral diode laser cyclophotocoagulation is effective in lowering IOP in eyes with intractable glaucoma with few side effects in Indian subjects.
Open angle glaucoma as a manifestation of Waardenburg′s syndrome.
Gupta Viney,Aggarwal Harish
Indian Journal of Ophthalmology , 2000,
Abstract: Waardenburg′s syndrome is a rare, autosomal dominant disorder, with several clinical signs, each with variable penetrance. We report this case of Waardenburg′s syndrome with bilateral open-angle glaucoma with unique gonioscopic findings.
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