2,893 research outputs found
Detection of high levels of congenital transmission of toxoplasma gondii in natural urban populations of mus domesticus
The relative importance of different transmission routes of Toxoplasma gondii has been a matter for debate. This ubiquitous parasite is generally thought to be transmitted by infective oocysts excreted by the definitive host, the cat. Ingestion of undercooked meat has also been considered an important route of transmission in many mammals while congenital transmission has generally been considered relatively rare. Experimental studies demonstrate the ability of T. gondii to be transmitted congenitally, but few studies have investigated the frequency of this transmission route in natural populations. We use PCR amplification of the SAG1 gene to investigate the frequency of congenital transmission in a wild population of mice (Mus domesticus) and show that congenital transmission is occurring in 75% of pregnancies in this population. Furthermore, for infected pregnant mice, transmission occurs to at least one foetus in 100% of cases while variable penetrance of congenital infection is observed. These high levels of congenital transmission in this wild population of mice, taken together with other recent data on congenital transmission in sheep, suggests that this phenomenon might be more widespread than previously thought
Kinematic determinants of early acceleration in field sport athletes
Acceleration performance is important for field sport athletes that require a high level of repeat sprint ability. Although acceleration is widely trained for, there is little evidence outlining which kinematic factors delineate between good and poor acceleration. The aim of this study was to investigate the kinematic differences between individuals with fast and slow acceleration. Twenty field sport athletes were tested for sprint ability over the first three steps of a 15m sprint. Subjects were filmed at high speed to determine a range of lower body kinematic measures. For data analysis, subjects were then divided into relatively fast (n = 10) and slow (n = 10) groups based on their horizontal velocity. Groups were then compared across kinematic measures, including stride length and frequency, to determine whether they accounted for observed differences in sprint velocity. The results showed the fast group had significantly lower (∼11-13%) left and right foot contact times (p < .05), and an increased stride frequency (∼9%), as compared to the slow group. Knee extension was also significantly different between groups (p < .05). There was no difference found in stride length. It was concluded that those subjects who are relatively fast in early acceleration achieve this through reduced ground contact times resulting in an improved stride frequency. Training for improved acceleration should be directed towards using coaching instructions and drills that specifically train such movement adaptations. ©Journal of Sports Science and Medicine (2003)
The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations
Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4·4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18·9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues
The relationship between lower body stiffness and injury incidence in female netballers
© 2017 Informa UK Limited, trading as Taylor & Francis Group. The aim of this study was to provide contemporary information on injury rates in an elite and sub-elite netball population and to explore the relationship between lower body stiffness and lower body injuries. One elite and two sub-elite teams of female netballers (n = 29) performed the vertical hop test to assess active lower body stiffness (Kvert) and myometry to assess quasi-static stiffness. Lower body injuries were monitored via self-reporting and liaison with physiotherapists. Twelve lower body non-contact injuries were sustained by 10 players, equating to 11.29 lower body injuries per 1,000 exposure hours. The most commonly injured sites were the calf (33%) and ankle (25%). No significant differences between Kvert of injured and non-injured players were reported, however, injured elite players recorded significantly higher season mean quasi-static stiffness in the soleus (p = 0.037) and Achilles (p = 0.004) than non-injured elite players. Elite and sub-elite netball players recorded a higher injury incidence than previous reports of injuries in recreational netballers. Within the constraints of the study, relatively high stiffness of the soleus and Achilles appears to be related to lower body non-contact injury incidence in female netballers, particularly at the elite level. These results provide a basis for development of injury prevention strategies
Ventral striatum activity in response to reward: differences between bipolar I and II disorders.
addresses: MRC Center for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, UK. [email protected]: PMCID: PMC3640293types: Journal Article; Research Support, Non-U.S. Gov'tThis is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/3.0/ and http://creativecommons.org/licenses/by-nc/3.0/legalcode.Copyright © 2013 by the American Psychiatric AssociationThe official published article is available online at http://ajp.psychiatryonline.org/article.aspx?articleid=1676088Little is known about the neurobiology of bipolar II disorder. While bipolar I disorder is associated with abnormally elevated activity in response to reward in the ventral striatum, a key component of reward circuitry, no studies have compared reward circuitry function in bipolar I and bipolar II disorders. Furthermore, associations among reward circuitry activity, reward sensitivity, and striatal volume remain underexplored in bipolar and healthy individuals. The authors examined reward activity in the ventral striatum in participants with bipolar I and II disorders and healthy individuals, the relationships between ventral striatal activity and reward sensitivity across all participants, and between-group differences in striatal gray matter volume and relationships with ventral striatal activity across all participants
A Java Program for LRE-Based Real-Time qPCR that Enables Large-Scale Absolute Quantification
Background: Linear regression of efficiency (LRE) introduced a new paradigm for real-time qPCR that enables large-scale absolute quantification by eliminating the need for standard curves. Developed through the application of sigmoidal mathematics to SYBR Green I-based assays, target quantity is derived directly from fluorescence readings within the central region of an amplification profile. However, a major challenge of implementing LRE quantification is the labor intensive nature of the analysis. Findings: Utilizing the extensive resources that are available for developing Java-based software, the LRE Analyzer was written using the NetBeans IDE, and is built on top of the modular architecture and windowing system provided by the NetBeans Platform. This fully featured desktop application determines the number of target molecules within a sample with little or no intervention by the user, in addition to providing extensive database capabilities. MS Excel is used to import data, allowing LRE quantification to be conducted with any real-time PCR instrument that provides access to the raw fluorescence readings. An extensive help set also provides an in-depth introduction to LRE, in addition to guidelines on how to implement LRE quantification. Conclusions: The LRE Analyzer provides the automated analysis and data storage capabilities required by large-scale qPCR projects wanting to exploit the many advantages of absolute quantification. Foremost is the universal perspective afforded by absolute quantification, which among other attributes, provides the ability to directly compare quantitative data produced by different assays and/or instruments. Furthermore, absolute quantification has important implications for gene expression profiling in that it provides the foundation for comparing transcript quantities produced by any gene with any other gene, within and between samples
The Thalamus and Brainstem Act As Key Hubs in Alterations of Human Brain Network Connectivity Induced by Mild Propofol Sedation
Despite their routine use during surgical procedures, no consensus has yet been reached on the precise mechanisms by which hypnotic anesthetic agents produce their effects. Molecular, animal and human studies have suggested disruption of thalamocortical communication as a key component of anesthetic action at the brain systems level. Here, we used the anesthetic agent, propofol, to modulate consciousness and to evaluate differences in the interactions of remote neural networks during altered consciousness. We investigated the effects of propofol, at a dose that produced mild sedation without loss of consciousness, on spontaneous cerebral activity of 15 healthy volunteers using functional magnetic resonance imaging (fMRI), exploiting oscillations (<0.1 Hz) in blood oxygenation level-dependent signal across functionally connected brain regions. We considered the data as a graph, or complex network of nodes and links, and used eigenvector centrality (EC) to characterize brain network properties. The EC mapping of fMRI data in healthy humans under propofol mild sedation demonstrated a decrease of centrality of the thalamus versus an increase of centrality within the pons of the brainstem, highlighting the important role of these two structures in regulating consciousness. Specifically, the decrease of thalamus centrality results from its disconnection from a widespread set of cortical and subcortical regions, while the increase of brainstem centrality may be a consequence of its increased influence, in the mildly sedated state, over a few highly central cortical regions key to the default mode network such as the posterior and anterior cingulate cortices
Improved FPT algorithms for weighted independent set in bull-free graphs
Very recently, Thomass\'e, Trotignon and Vuskovic [WG 2014] have given an FPT
algorithm for Weighted Independent Set in bull-free graphs parameterized by the
weight of the solution, running in time . In this article
we improve this running time to . As a byproduct, we also
improve the previous Turing-kernel for this problem from to .
Furthermore, for the subclass of bull-free graphs without holes of length at
most for , we speed up the running time to . As grows, this running time is
asymptotically tight in terms of , since we prove that for each integer , Weighted Independent Set cannot be solved in time in the class of -free graphs unless the
ETH fails.Comment: 15 page
Mitochondrial content is preserved throughout disease progression in the mdx mouse model of Duchenne muscular dystrophy, regardless of taurine supplementation
Mitochondrial dysfunction is a pathological feature of Duchenne muscular dystrophy (DMD), a debilitating and fatal neuromuscular disorder characterized by progressive muscle wasting and weakness. Mitochondria are a source of cellular ATP involved in Ca2+ regulation and apoptotic signaling. Ameliorating aberrant mitochondrial function has therapeutic potential for reducing DMD disease severity. The dystrophic mdx mouse exhibits peak muscle damage at 21–28 days, which stabilizes after 8 wk. The amino acid taurine is implicated in mitochondrial health and function, with endogenous concentrations low when measured during the cycle of peak muscle damage in mdx mice. Using whole soleus and extensor digitorum longus (EDL) muscle homogenates from 28- and 70-day mdx mice, we found that there was no change in native state mitochondrial complexes using blue native-PAGE. NADH:ubiquinone oxidotreductase subunit-A9 (NDUFA9) protein abundance was lower in soleus muscle of 28- and 70-day mdx mice and EDL muscle of 70-day mdx mice compared with same muscles in WT (C57/BL10ScSn) animals. There were age-dependent increases in both NDUFA9 protein abundance and citrate synthase activity in soleus muscles of mdx and wild-type mice. There was no change in abundances of mitochondrial dynamics proteins mitofusin 2 (Mfn2) and mitochondrial dynamics protein 49 (MiD49). Taurine administration essentially did not affect any measurements of mitochondria. Collectively, these findings suggest mitochondrial content and dynamics are not reduced in the mdx mouse regardless of disease severity. We also elucidate that taurine affords no significant benefit to mitochondrial content or dynamics in the mdx mouse at either 28 or 70 days. </jats:p
A novel TBP-TAF complex on RNA Polymerase II-transcribed snRNA genes
Initiation of transcription of most human genes transcribed by RNA polymerase II (RNAP II) requires the formation of a preinitiation complex comprising TFIIA, B, D, E, F, H and RNAP II. The general transcription factor TFIID is composed of the TATA-binding protein and up to 13 TBP-associated factors. During transcription of snRNA genes, RNAP II does not appear to make the transition to long-range productive elongation, as happens during transcription of protein-coding genes. In addition, recognition of the snRNA gene-type specific 3′ box RNA processing element requires initiation from an snRNA gene promoter. These characteristics may, at least in part, be driven by factors recruited to the promoter. For example, differences in the complement of TAFs might result in differential recruitment of elongation and RNA processing factors. As precedent, it already has been shown that the promoters of some protein-coding genes do not recruit all the TAFs found in TFIID. Although TAF5 has been shown to be associated with RNAP II-transcribed snRNA genes, the full complement of TAFs associated with these genes has remained unclear. Here we show, using a ChIP and siRNA-mediated approach, that the TBP/TAF complex on snRNA genes differs from that found on protein-coding genes. Interestingly, the largest TAF, TAF1, and the core TAFs, TAF10 and TAF4, are not detected on snRNA genes. We propose that this snRNA gene-specific TAF subset plays a key role in gene type-specific control of expression
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