71 research outputs found

    Cognitive dysfunction in naturally occurring canine idiopathic epilepsy

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    Globally, epilepsy is a common serious brain disorder. In addition to seizure activity, epilepsy is associated with cognitive impairments including static cognitive impairments present at onset, progressive seizure-induced impairments and co-morbid dementia. Epilepsy occurs naturally in domestic dogs but its impact on canine cognition has yet to be studied, despite canine cognitive dysfunction (CCD) recognised as a spontaneous model of dementia. Here we use data from a psychometrically validated tool, the canine cognitive dysfunction rating (CCDR) scale, to compare cognitive dysfunction in dogs diagnosed with idiopathic epilepsy (IE) with controls while accounting for age. An online cross-sectional study resulted in a sample of 4051 dogs, of which n = 286 had been diagnosed with IE. Four factors were significantly associated with a diagnosis of CCD (above the diagnostic cut-off of CCDR ≥50): (i) epilepsy diagnosis: dogs with epilepsy were at higher risk; (ii) age: older dogs were at higher risk; (iii) weight: lighter dogs (kg) were at higher risk; (iv) training history: dogs with more exposure to training activities were at lower risk. Impairments in memory were most common in dogs with IE, but progression of impairments was not observed compared to controls. A significant interaction between epilepsy and age was identified, with IE dogs exhibiting a higher risk of CCD at a young age, while control dogs followed the expected pattern of low-risk throughout middle age, with risk increasing exponentially in geriatric years. Within the IE sub-population, dogs with a history of cluster seizures and high seizure frequency had higher CCDR scores. The age of onset, nature and progression of cognitive impairment in the current IE dogs appear divergent from those classically seen in CCD. Longitudinal monitoring of cognitive function from seizure onset is required to further characterise these impairments

    A biosynthetic pathway to isovaleryl-CoA in myxobacteria: the involvement of the mevalonate pathway

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    A biosynthetic shunt pathway branching from the mevalonate pathway and providing starter units for branched-chain fatty acid and secondary metabolite biosynthesis has been identified in strains of the myxobacterium Stigmatella aurantiaca. This pathway is upregulated when the branched-chain alpha-keto acid dehydrogenase gene (bkd) is inactivated, thus impairing the normal branched-chain amino acid degradation process. We previously proposed that, in this pathway, isovaleryl-CoA is derived from 3,3-dimethylacrylyl-CoA (DMA-CoA). Here we show that DMA-CoA is an isomerization product of 3-methylbut-3-enoyl-CoA (3MB-CoA). This compound is directly derived from 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) by a decarboxylation/ dehydration reaction resembling the conversion of mevalonate 5-diphosphate to isopentenyl diphosphate. Incubation of cell-free extracts of a bkd mutant with HMG-CoA gave product(s) with the molecular mass of 3MB-CoA or DMA-CoA. The shunt pathway most likely also operates reversibly and provides an alternative source for the monomers of isoprenoid biosynthesis in myxobacteria that utilize L-leucine as precursor

    Impact of prior or concomitant seasonal influenza vaccination on MF59-adjuvanted H1N1v vaccine (Focetria) in adult and elderly subjects

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    Background: When H1N1v vaccines become widely available, most elderly subjects will have already received their seasonal influenza vaccination. Adults seeking H1N1v vaccination may be offered seasonal vaccine as well. We investigated prior seasonal vaccination in adult and elderly subjects, and concomitant vaccination with seasonal vaccine in adults, on the tolerability and immunogenicity of the Novartis MF59-adjuvanted H1N1v vaccine, Focetria \uae. Methods: A total of 264 adult (four groups) and 154 elderly (three groups) subjects were enrolled. The licensure study cohorts for plain (Agrippal \uae) and MF59-adjuvanted (Fluad \uae) 2009-2010 seasonal vaccines were invited to receive Focetria 3 months later, with seasonal vaccine-na\uefve controls, and adults who received Focteria and seasonal vaccine concomitantly. Immunogenicity of all vaccines was assessed by haemagglutination inhibition on Days 1 and 22, safety and reactogenicity were monitored using patient diaries. Results: All adult and elderly groups met all the European CHMP licensing criteria for H1N1v, as did adults receiving concomitant seasonal vaccine for the three seasonal strains. Vaccines were generally well tolerated, causing no SAEs, and profiles typical of MF59-adjuvanted vaccines. Reactions were mainly mild or moderate and transient, and unaffected by prior or concomitant seasonal vaccination except for elderly subjects previously given MF59-adjuvanted seasonal vaccine, whose reaction rates to Focetria were about half those seen in groups receiving their first MF59 vaccine. Conclusion: One dose of MF59-adjuvanted H1N1v vaccine met the licensure criteria for adult and elderly subjects 3 months after seasonal vaccination, or concomitantly with seasonal vaccine in adults, without impacting the tolerability or immunogenicity of either vaccine, thus facilitating mass influenza immunisation campaigns

    In vitro reconstitution of the myxochelin biosynthetic machinery of Stigmatella aurantiaca Sg a15: Biochemical characterization of a reductive release mechanism from nonribosomal peptide synthetases

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    Microorganisms produce iron-chelating compounds to sequester the iron essential for growth from the environment. Many of these compounds are biosynthesized by nonribosomal peptide synthetases, some in cooperation with polyketide synthases. Myxochelins are produced by the myxobacterium Stigmatella aurantiaca Sg a15, and the corresponding gene cluster was cloned recently. We have undertaken to express heterologously the myxochelin biosynthetic machinery in Escherichia coli. To activate the involved proteins posttranslationally, they were coexpressed with the phosphopantetheinyltransferase MtaA from the myxothiazol biosynthetic gene cluster. Phosphopantetheinylation of the carrier proteins could be verified by protein mass analysis. Six active domains in proteins MxcE, MxcF, and MxcG are capable of assembling myxochelin from ATP, NAD(P)H, lysine, and 2,3-dihydroxybenzoic acid in vitro. This fact demonstrates that the condensation domain of MxcG performs two condensation reactions, creating the aryl-capped α-amide and the aryl-capped γ-amide of the molecule. A previously unknown type of reductive release is performed by the reduction domain of MxcG, which alternatively uses NADPH and NADH to set free the peptidyl-carrier protein-bound thioester as an aldehyde and further reduces it to the alcohol structure that can be found in myxochelin A. This type of reductive release seems to be a general mechanism in polyketide and nonribosomal peptide biosynthesis, because several systems with C-terminal similarity to the reductase domain of MxcG can be found in the databases. Alternatively, the aldehyde can be transaminated, giving rise to a terminal amine
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