1,606 research outputs found

    The value of hippocampal and temporal horn volumes and rates of change in predicting future conversion to AD.

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    Hippocampal pathology occurs early in Alzheimer disease (AD), and atrophy, measured by volumes and volume changes, may predict which subjects will develop AD. Measures of the temporal horn (TH), which is situated adjacent to the hippocampus, may also indicate early changes in AD. Previous studies suggest that these metrics can predict conversion from amnestic mild cognitive impairment (MCI) to AD with conversion and volume change measured concurrently. However, the ability of these metrics to predict future conversion has not been investigated. We compared the abilities of hippocampal, TH, and global measures to predict future conversion from MCI to AD. TH, hippocampi, whole brain, and ventricles were measured using baseline and 12-month scans. Boundary shift integral was used to measure the rate of change. We investigated the prediction of conversion between 12 and 24 months in subjects classified as MCI from baseline to 12 months. All measures were predictive of future conversion. Local and global rates of change were similarly predictive of conversion. There was evidence that the TH expansion rate is more predictive than the hippocampal atrophy rate (P=0.023) and that the TH expansion rate is more predictive than the TH volume (P=0.036). Prodromal atrophy rates may be useful predictors of future conversion to sporadic AD from amnestic MCI

    Automatic online motor control is intact in Parkinson’s disease with and without perceptual awareness

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    In the double-step paradigm, healthy human participants automatically correct reaching movements when targets are displaced. Motor deficits are prominent in Parkinson’s disease (PD) patients. In the lone investigation of online motor correction in PD using the double-step task, a recent study found that PD patients performed unconscious adjustments appropriately but seemed impaired for consciously-perceived modifications. Conscious perception of target movement was achieved by linking displacement to movement onset. PD-related bradykinesia disproportionately prolonged preparatory phases for movements to original target locations for patients, potentially accounting for deficits. Eliminating this confound in a double-step task, we evaluated the effect of conscious awareness of trajectory change on online motor corrections in PD. On and off dopaminergic therapy, PD patients (n = 14) and healthy controls (n = 14) reached to peripheral visual targets that remained stationary or unexpectedly moved during an initial saccade. Saccade latencies in PD are comparable to controls’. Hence, target displacements occurred at equal times across groups. Target jump size affected conscious awareness, confirmed in an independent target displacement judgment task. Small jumps were subliminal, but large target displacements were consciously perceived. Contrary to the previous result, PD patients performed online motor corrections normally and automatically, irrespective of conscious perception. Patients evidenced equivalent movement durations for jump and stay trials, and trajectories for patients and controls were identical, irrespective of conscious perception. Dopaminergic therapy had no effect on performance. In summary, online motor control is intact in PD, unaffected by conscious perceptual awareness. The basal ganglia are not implicated in online corrective responses

    Carcass Gain, Efficiency, and Profitability of Steers at Extended Days on Feed

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    Steers were individually fed for 22 and 44 days longer than the industry average marketing point of 0.5” backfat to determine carcass- based gain, efficiency, and deposition changes throughout the feeding period (142, 163, and 184 days on feed). Premiums and discounts for yield grade, quality grade, and overweight carcasses were applied to determine profitability. Feeding steers for 22 and 44 days longer increased carcass weight, quality grade, and yield grade 4 and 5s. Steers fed 44 days longer had increased total revenue and profit per head despite a decrease in live gain and efficiency

    A methodology for composing well-defined character descriptions.

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    Taxonomy has been described as “the science of documenting biodiversity”, which involves collecting, naming, describing, identifying and classifying specimens of organisms (Keogh, 1995). Descriptions are the fundamental information units used in the process of constructing classifications and communicating taxonomic concepts. The quality of stored description data is limited by the lack of a formal model and methodology for composing specimen descriptions, and by the absence of an agreed defined terminology. This impedes the communication, interpretation and reuse of original descriptions. This paper describes a novel approach to composing and recording taxonomic descriptions of botanical specimens. An underlying model for creating character descriptions is presented together with a process for creating an ontology of defined terms, which will be used to compose these description elements. It is hoped that these developments will facilitate the unambiguous interpretation of descriptions and enhance the taxonomic process

    A methodology for composing well-defined character descriptions.

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    Taxonomy has been described as “the science of documenting biodiversity”, which involves collecting, naming, describing, identifying and classifying specimens of organisms (Keogh, 1995). Descriptions are the fundamental information units used in the process of constructing classifications and communicating taxonomic concepts. The quality of stored description data is limited by the lack of a formal model and methodology for composing specimen descriptions, and by the absence of an agreed defined terminology. This impedes the communication, interpretation and reuse of original descriptions. This paper describes a novel approach to composing and recording taxonomic descriptions of botanical specimens. An underlying model for creating character descriptions is presented together with a process for creating an ontology of defined terms, which will be used to compose these description elements. It is hoped that these developments will facilitate the unambiguous interpretation of descriptions and enhance the taxonomic process

    What's in a virus? Folk understandings of hepatitis C infection and infectiousness among injecting drug users in Kings Cross, Sydney

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    BACKGROUND: To explore folk understandings of blood borne virus infection and infectiousness among injecting drug users in Kings Cross, Sydney. METHODS: Observational fieldwork was conducted in Kings Cross over a four month period. In-depth interviews with 24 current injectors and 4 key informants recruited from King Cross were undertaken. RESULTS: Hepatitis C (HCV) generated different meanings from HIV. HIV was considered "the dreaded" and generated fear of infection and dire disease progression. Whereas HCV was considered non-desirable but less threatening than HIV. The risks of transmitting HCV through sharing injecting paraphernalia was poorly understood. Some believed HCV infection was linked to poor hygiene and dirty water. Jaundice was mistakenly thought to indicate HCV infection and was used to gauge infectiousness. Many were confused about their current hepatitis C serostatus. Some participants thought they had a "dormant antibody" or that they had a "mild case" of infection. Participants were unsure what this meant for their own health or for their potential to infect others. CONCLUSION: Participants displayed confusion about transmission risks for hepatitis C, conflating blood awareness and hygiene health promotion messages. Participants' reliance on the symptom of jaundice to gauge serostatus places them at risk of transmitting and contracting HCV. Participants were confused about what a positive HCV diagnosis meant for their own health and their ability to infect others. Education is needed to debunk misconceptions about jaundice and clarify medical terms such as 'antibody' at the time of diagnosis. Further clarification of messages about injecting hygiene and blood awareness are also required

    Exposure-based Interventions for the management of individuals with high levels of needle fear across the lifespan: a clinical practice guideline and call for further research

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    Needle fear typically begins in childhood and represents an important health-related issue across the lifespan. Individuals who are highly fearful of needles frequently avoid health care. Although guidance exists for managing needle pain and fear during procedures, the most highly fearful may refuse or abstain from such procedures. The purpose of a clinical practice guideline (CPG) is to provide actionable instruction on the management of a particular health concern; this guidance emerges from a systematic process. Using evidence from a rigorous systematic review interpreted by an expert panel, this CPG provides recommendations on exposure-based interventions for high levels of needle fear in children and adults. The AGREE-II, GRADE, and Cochrane methodologies were used. Exposure-based interventions were included. The included evidence was very low quality on average. Strong recommendations include the following. In vivo (live/in person) exposure-based therapy is recommended (vs. no treatment) for children seven years and older and adults with high levels of needle fear. Non-in vivo (imaginal, computer-based) exposure (vs. no treatment) is recommended for individuals (over seven years of age) who are unwilling to undergo in vivo exposure. Although there were no included trials which examined children \u3c 7 years, exposure-based interventions are discussed as good clinical practice. Implementation considerations are discussed and clinical tools are provided. Utilization of these recommended practices may lead to improved health outcomes due to better health care compliance. Research on the understanding and treatment of high levels of needle fear is urgently needed; specific recommendations are provided
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