457 research outputs found
Virtual geological outcrops - fieldwork and analysis made less exhaustive?
For geologists studying outcrops in the field, there is an ever‐increasing need for the acquisition of accurate and comprehensive data, whatever their purpose. Fortunately, this need is mirrored by an expanding range of digital data capturing technologies that provide the possibility of examining geological outcrops in minute detail from the desktop. Although difficult technologically, there is also a need to combine differing datasets into a single, accurate, digital model that will allow field geologists to place their data in a wider context. This paper examines the techniques available, and highlights new Light Detection and Ranging (LIDAR) technology which should prove to be a unifying technique, being able to combine images and local coordinates on‐site
A genetic investigation of the muscle and neuronal channelopathies: from Sanger to next-generation sequencing
The neurological channelopathies are a group of hereditary, episodic and frequently debilitating diseases often caused by dysfunction of voltage-gated ion channels. This thesis reports genetic studies of carefully clinically characterised patient cohorts with different episodic neurological and neuromuscular disorders including paroxysmal dyskinesias, episodic ataxia, periodic paralysis and episodic rhabdomyolysis. Genetic and clinical heterogeneity has in the past, using traditional Sanger sequencing methods, made genetic diagnosis difficult and time consuming. This has led to many patients and families being undiagnosed. Here, different sequencing technologies were employed to define the genetic architecture in the paroxysmal disorders. Initially, Sanger sequencing was employed to screen the three known paroxysmal dyskinesia genes in a large cohort of paroxysmal movement disorder patients and smaller mixed episodic phenotype cohort. A genetic diagnosis was achieved in 39% and 13% of the cohorts respectively, and the genetic and phenotypic overlap was highlighted. Subsequently, next-generation sequencing panels were developed, for the first time in our laboratory. Small custom-designed amplicon-based panels were used for the skeletal muscle and neuronal channelopathies. They offered considerable clinical and practical benefit over traditional Sanger sequencing and revealed further phenotypic overlap, however there were still problems to overcome with incomplete coverage. Large custom and non-custom pull-down panels were used to investigate patients with recurrent rhabdomyolysis patients. The contribution of genetic abnormalities was determined, and it was concluded that while the contribution of the RYR1 was substantial, it was minimal for the classic voltage-gated ion channels SCN4A and CACNA1S Lastly, whole-exome sequencing was applied to two large undiagnosed possible channelopathy families. One family was found to indeed harbour a channelopathy mutation, whilst the other did not. Overall, next-generation sequencing proved to be a more thorough and efficient method for channelopathy genetic diagnosis and several novel findings throughout the thesis expanded the current knowledge within the field
Rhabdomyolysis: a genetic perspective
Rhabdomyolysis (RM) is a clinical emergency characterized by fulminant skeletal muscle damage and release of intracellular muscle components into the blood stream leading to myoglobinuria and, in severe cases, acute renal failure. Apart from trauma, a wide range of causes have been reported including drug abuse and infections. Underlying genetic disorders are also a cause of RM and can often pose a diagnostic challenge, considering their marked heterogeneity and comparative rarity.In this paper we review the range of rare genetic defects known to be associated with RM. Each gene has been reviewed for the following: clinical phenotype, typical triggers for RM and recommended diagnostic approach. The purpose of this review is to highlight the most important features associated with specific genetic defects in order to aid the diagnosis of patients presenting with hereditary causes of recurrent RM
Protein profiles in Tc1 mice implicate novel pathway perturbations in the Down syndrome brain
Tc1 mouse model of Down syndrome (DS) is functionally trisomic for ∼120 human chromosome 21 (HSA21) classical protein-coding genes. Tc1 mice display features relevant to the DS phenotype, including abnormalities in learning and memory and synaptic plasticity. To determine the molecular basis for the phenotypic features, the levels of 90 phosphorylation-specific and phosphorylation-independent proteins were measured by Reverse Phase Protein Arrays in hippocampus and cortex, and 64 in cerebellum, of Tc1 mice and littermate controls. Abnormal levels of proteins involved in MAP kinase, mTOR, GSK3B and neuregulin signaling were identified in trisomic mice. In addition, altered correlations among the levels of N-methyl-D-aspartate (NMDA) receptor subunits and the HSA21 proteins amyloid beta (A4) precursor protein (APP) and TIAM1, and between immediate early gene (IEG) proteins and the HSA21 protein superoxide dismutase-1 (SOD1) were found in the hippocampus of Tc1 mice, suggesting altered stoichiometry among these sets of functionally interacting proteins. Protein abnormalities in Tc1 mice were compared with the results of a similar analysis of Ts65Dn mice, a DS mouse model that is trisomic for orthologs of 50 genes trisomic in the Tc1 plus an additional 38 HSA21 orthologs. While there are similarities, abnormalities unique to the Tc1 include increased levels of the S100B calcium-binding protein, mTOR proteins RAPTOR and P70S6, the AMP-kinase catalytic subunit AMPKA, the IEG proteins FBJ murine osteosarcoma viral oncogene homolog (CFOS) and activity-regulated cytoskeleton-associated protein (ARC), and the neuregulin 1 receptor ERBB4. These data identify novel perturbations, relevant to neurological function and to some seen in Alzheimer's disease, that may occur in the DS brain, potentially contributing to phenotypic features and influencing drug responses
Evaluation of a Bayesian inference network for ligand-based virtual screening
Background
Bayesian inference networks enable the computation of the probability that an event will occur. They have been used previously to rank textual documents in order of decreasing relevance to a user-defined query. Here, we modify the approach to enable a Bayesian inference network to be used for chemical similarity searching, where a database is ranked in order of decreasing probability of bioactivity.
Results
Bayesian inference networks were implemented using two different types of network and four different types of belief function. Experiments with the MDDR and WOMBAT databases show that a Bayesian inference network can be used to provide effective ligand-based screening, especially when the active molecules being sought have a high degree of structural homogeneity; in such cases, the network substantially out-performs a conventional, Tanimoto-based similarity searching system. However, the effectiveness of the network is much less when structurally heterogeneous sets of actives are being sought.
Conclusion
A Bayesian inference network provides an interesting alternative to existing tools for ligand-based virtual screening
A Geographically-Restricted but Prevalent Mycobacterium tuberculosis Strain Identified in the West Midlands Region of the UK between 1995 and 2008
Background: We describe the identification of, and risk factors for, the single most prevalent Mycobacterium tuberculosis strain in the West Midlands region of the UK.Methodology/Principal Findings: Prospective 15-locus MIRU-VNTR genotyping of all M. tuberculosis isolates in the West Midlands between 2004 and 2008 was undertaken. Two retrospective epidemiological investigations were also undertaken using univariable and multivariable logistic regression analysis. The first study of all TB patients in the West Midlands between 2004 and 2008 identified a single prevalent strain in each of the study years (total 155/3,056 (5%) isolates). This prevalent MIRU-VNTR profile (32333 2432515314 434443183) remained clustered after typing with an additional 9-loci MIRU-VNTR and spoligotyping. The majority of these patients (122/155, 79%) resided in three major cities located within a 40 km radius. From the apparent geographical restriction, we have named this the "Mercian" strain. A multivariate analysis of all TB patients in the West Midlands identified that infection with a Mercian strain was significantly associated with being UK-born (OR = 9.03, 95% CI = 4.56-17.87, p 65 years old (OR = 0.25, 95% CI = 0.09-0.67, p < 0.01). A second more detailed investigation analyzed a cohort of 82 patients resident in Wolverhampton between 2003 and 2006. A significant association with being born in the UK remained after a multivariate analysis (OR = 9.68, 95% CI = 2.00-46.78, p < 0.01) and excess alcohol intake and cannabis use (OR = 6.26, 95% CI = 1.45-27.02, p = .01) were observed as social risk factors for infection.Conclusions/Significance: The continued consistent presence of the Mercian strain suggests ongoing community transmission. Whilst significant associations have been found, there may be other common risk factors yet to be identified. Future investigations should focus on targeting the relevant risk groups and elucidating the biological factors that mediate continued transmission of this strain
Slow and fast diffusion in a lead sulphate gravity separation process
A model for the growth of lead sulphate particles in a gravity separation system
from the crystal glassware industry is presented. The lead sulphate particles are an undesirable
byproduct, and thus the model is used to ascertain the optimal system temperature configuration
such that particle extraction is maximised. The model describes the evolution of a single,
spherical particle due to the mass flux of lead particles from a surrounding acid solution. We
divide the concentration field into two separate regions. Specifically, a relatively small boundary
layer region around the particle is characterised by fast diffusion, and is thus considered quasistatic.
In contrast, diffusion in the far-field is slower, and hence assumed to be time-dependent.
The final system consisting of two nonlinear, coupled ordinary differential equations for the
particle radius and lead concentration, is integrated numerically
The need for biochemical testing in beta‐enolase deficiency in the genomic era
Glycogen storage disease type XIII (GSDXIII) is a very rare inherited metabolic myopathy characterized by autosomal‐recessive mutations in the ENO3 gene resulting in muscle β‐enolase deficiency, an enzymatic defect of the distal part of glycolysis. Enzyme kinetic studies of two patients presenting with exertion intolerance and recurrent rhabdomyolysis are reported. Next generation sequencing confirmed patient 1 was homozygous for p.E187K in ENO3, while patient 2 was homozygous for p.C357Y. ENO3 variants pathogenicity was confirmed by functional studies in skeletal muscle. p.E187K caused extremely low total enolase activity. p.C357Y was associated with a higher level of residual activity but kinetic studies showed a lower maximum work rate (Vmax). This study illustrates that GSDXIII may be caused by either null mutations leading to β‐enolase deficiency or by mutations that alter the enzyme's kinetic profile. This study highlights the importance of carrying out functional studies as part of the diagnostic process following the identification of variants with next generation sequencing
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