5,721 research outputs found
Sending Your Grandparents to University Increases Cognitive Reserve: The Tasmanian Healthy Brain Project.
Increasing an individual’s level of cognitive reserve (CR) has been suggested as a nonpharmacological
approach to reducing the risk for Alzheimer’s disease. We examined changes in CR in older
adults participating over 4 years in the Tasmanian Healthy Brain Project. Method: A sample of 459
healthy older adults between 50 and 79 years of age underwent a comprehensive annual assessment of
current CR, neuropsychological function, and psychosocial factors over a 4-year period. The intervention
group of 359 older adults (M � 59.61 years, SD � 6.67) having completed a minimum of 12 months
part-time university study were compared against a control reference group of 100 adults (M � 62.49
years, SD � 6.24) who did not engage in further education. Results: Growth mixture modeling
demonstrated that 44.3% of the control sample showed no change in CR, whereas 92.5% of the further
education participants displayed a significant linear increase in CR over the 4 years of the study. These
results indicate that older adults engaging in high-level mental stimulation display an increase in CR over
a 4-year period. Conclusion: Increasing mental activity in older adulthood may be a viable strategy to
improve cognitive function and offset cognitive decline associated with normal aging
The hand of Homo naledi
A nearly complete right hand of an adult hominin was recovered from the Rising Star cave system, South Africa. Based on associated hominin material, the bones of this hand are attributed to Homo naledi. This hand reveals a long, robust thumb and derived wrist morphology that is shared with Neandertals and modern humans, and considered adaptive for intensified manual manipulation. However, the finger bones are longer and more curved than in most australopiths, indicating frequent use of the hand during life for strong grasping during locomotor climbing and suspension. These markedly curved digits in combination with an otherwise human-like wrist and palm indicate a significant degree of climbing, despite the derived nature of many aspects of the hand and other regions of the postcranial skeleton in H. naledi
Pharmacokinetics of Antituberculosis Drugs in HIV-Positive and HIV-Negative Adults in Malawi
Limited data address the impact of HIV co-infection on the pharmacokinetics of anti-tuberculosis drugs in Sub-Saharan Africa. 47 Malawian adults underwent rich pharmacokinetic sampling at 0-0.5-1-2-3-4-6-8 and 24 hours post-dose. 51% were male; mean age was 34 years. 65% were HIV-positive with a mean CD4 count of 268 cells/μL. Anti-tuberculosis drugs were administered as fixed-dose combinations (rifampicin150mg/isoniazid75mg/pyrazinamide400mg/ethambutol275mg) according to recommended weight bands. Plasma drug concentrations were determined by high-performance liquid chromatography (rifampicin and pyrazinamide) or liquid chromatography-mass spectrometry (isoniazid and ethambutol). Data were analysed by non-compartmental methods and analysis of variance of log-transformed summary parameters. Pharmacokinetic parameters were: rifampicin Cmax 4.129 (2.474-5.596)μg/mL, AUC0-24 21.32 (13.57-28.60)μg/mL*h, half-life 2.45 (1.86-3.08)h; isoniazid Cmax 3.97 (2.979-4.544)μg/mL, AUC0-24 22.5 (14.75-34.59)μg/mL*h, half-life 3.93 (3.18-4.73)h.; pyrazinamide Cmax 34.21 (30.00-41.60)μg/mL, AUC0-24 386.6 (320.0-463.7)μg/mL*h, half-life 6.821 (5.71-8.042)h; ethambutol Cmax 2.278 (1.694-3.098)μg/mL, AUC0-24 20.41 (16.18-26.27)μg/mL*h, half-life 7.507 (6.517-8.696)h. Isoniazid PK data analysis suggested that around two-thirds were slow acetylators. Dose, weight and weight-adjusted dose were not significant predictors of PK exposure probably due to weight-banded dosing. In this first pharmacokinetic study of tuberculosis drugs in Malawian adults, measures of pharmacokinetic exposure were comparable with other studies for all first line drugs except for rifampicin, for which Cmax and AUC0-24 were notably lower. Contrary to some earlier observations, HIV status did not significantly affect AUC of any of the drugs. Increasing the dose of rifampicin could be beneficial in African adults, irrespective of HIV status. Current co-trimoxazole prophylaxis was associated with an increase in half-life of isoniazid of 41% (p=0.022). Possible competitive interactions between isoniazid and sulphamethoxazole mediated by the N-acetyltransferase pathway should therefore be explored further
Synthesis and Oligonucleotide Incorporation of Fluorescent Cytosine Analogue tC: a Promising Nucleic Acid Probe
The tricyclic cytosine, tC, is a fluorescent base analogue with excellent properties for investigating intrinsic characteristics of nucleic acid as well as interactions between nucleic acids and other molecules. Its unique fluorescence properties and insignificant influence on overall structure and dynamics of nucleic acid after incorporation makes tC particularly interesting in fluorescence resonance energy transfer and anisotropy measurements. We here describe a straightforward synthesis of the standard monomer form of tC for DNA solid-phase synthesis, the tC phosphoramidite, and its subsequent incorporation into oligonucleotides. The total synthesis of the tC phosphoramidite takes approximately 8 days and its incorporation and the subsequent oligonucleotide purification an additional day
Systematic Three-Dimensional Coculture Rapidly Recapitulates Interactions between Human Neurons and Astrocytes
© 2017 The Authors Human astrocytes network with neurons in dynamic ways that are still poorly defined. Our ability to model this relationship is hampered by the lack of relevant and convenient tools to recapitulate this complex interaction. To address this barrier, we have devised efficient coculture systems utilizing 3D organoid-like spheres, termed asteroids, containing pre-differentiated human pluripotent stem cell (hPSC)-derived astrocytes (hAstros) combined with neurons generated from hPSC-derived neural stem cells (hNeurons) or directly induced via Neurogenin 2 overexpression (iNeurons). Our systematic methods rapidly produce structurally complex hAstros and synapses in high-density coculture with iNeurons in precise numbers, allowing for improved studies of neural circuit function, disease modeling, and drug screening. We conclude that these bioengineered neural circuit model systems are reliable and scalable tools to accurately study aspects of human astrocyte-neuron functional properties while being easily accessible for cell-type-specific manipulations and observations. In this article, Krencik and colleagues show that high-density cocultures of pre-differentiated human astrocytes with induced neurons, from pluripotent stem cells, elicit mature characteristics by 3–5 weeks. This provides a faster and more defined alternative method to organoid cultures for investigating human neural circuit function.This work has been supported by the Paul G. Allen Family Foundation Award, SFARI Award 345471, NIMH ( R01MH099595-01 ), That Man May See, NIH-NEI ( EY002162 ) Core Grant for Vision Research, and the Research to Prevent Blindness Unrestricted Grant
Lessons from dynamic cadaver and invasive bone pin studies: do we know how the foot really moves during gait?
Background: This paper provides a summary of a Keynote lecture delivered at the 2009 Australasian Podiatry Conference. The aim of the paper is to review recent research that has adopted dynamic cadaver and invasive kinematics research approaches to better understand foot
and ankle kinematics during gait. It is not intended to systematically cover all literature related to foot and ankle kinematics (such as research using surface mounted markers). Since the paper is based on a keynote presentation its focuses on the authors own experiences and work in the main, drawing on the work of others where appropriate
Methods: Two approaches to the problem of accessing and measuring the kinematics of individual anatomical structures in the foot have been taken, (i) static and dynamic cadaver models, and (ii) invasive in-vivo research. Cadaver models offer the advantage that there is complete access to all the tissues of the foot, but the cadaver must be manipulated and loaded in a manner which replicates how the foot would have performed when in-vivo. The key value of invasive in-vivo foot kinematics research is the validity of the description of foot kinematics, but the key difficulty is how generalisable this data is to the wider population.
Results: Through these techniques a great deal has been learnt. We better understand the valuable contribution mid and forefoot joints make to foot biomechanics, and how the ankle and subtalar joints can have almost comparable roles. Variation between people in foot kinematics is high and
normal. This includes variation in how specific joints move and how combinations of joints move. The foot continues to demonstrate its flexibility in enabling us to get from A to B via a large number of different kinematic solutions.
Conclusion: Rather than continue to apply a poorly founded model of foot type whose basis is to make all feet meet criteria for the mechanical 'ideal' or 'normal' foot, we should embrace variation between feet and identify it as an opportunity to develop patient-specific clinical models of foot function
One size does not fit all - stroke survivor's views on group self-management interventions
INTRODUCTION: Stroke is the main cause of complex disability in the UK. Many stroke survivors feel abandoned when rehabilitation ends and more than half are left with long-term unmet needs. There is now emerging interest in whether group self-management programs (SMP) specifically for stroke survivors could help. However, more work is required to understand the acceptability of group SMPs to stroke survivors and the factors of concern that could impact efficacy. PURPOSE: The purpose of this study is to explore stroke survivor's views on (1) possible benefits of a group SMP, (2) possible challenges of a group SMP, and (3) when/where to implement a SMP in an individual's stroke journey. METHOD: Fourteen stroke survivors took part in semi-structured interviews, which were analyzed using an inductive thematic approach. RESULTS: Three main themes were identified in the data: (1) a space to share support, (2) it is not a one size fits all problem, and (3) how is it all going to happen? CONCLUSION: A varied group of stroke survivors can provide valuable insight and ideas about how group SMP's should be constructed. To the best of our knowledge, this is the first patient engagement study that explores group SMPs for stroke. In future work, researchers may find it helpful to consider the findings from this study to inform the design of group SMPs. Implications for Rehabilitation There is interest in whether unmet needs after stroke could be addressed through a group self-management program (SMP). Stroke survivors can provide valuable insight and ideas about how group SMPs should be constructed. Group SMPs should carefully consider: how to create a safe space in which stroke survivors feel comfortable, the impact of the facilitators, tailoring the group to the individual, the presence of carers, and the emotional impact of a group SMP
Effectiveness and cost-effectiveness of traditional and new partner notification technologies for curable sexually transmitted infections: observational study, systematic reviews and mathematical modelling.
BACKGROUND: Partner notification is essential to the comprehensive case management of sexually transmitted infections. Systematic reviews and mathematical modelling can be used to synthesise information about the effects of new interventions to enhance the outcomes of partner notification. OBJECTIVE: To study the effectiveness and cost-effectiveness of traditional and new partner notification technologies for curable sexually transmitted infections (STIs). DESIGN: Secondary data analysis of clinical audit data; systematic reviews of randomised controlled trials (MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials) published from 1 January 1966 to 31 August 2012 and of studies of health-related quality of life (HRQL) [MEDLINE, EMBASE, ISI Web of Knowledge, NHS Economic Evaluation Database (NHS EED), Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA)] published from 1 January 1980 to 31 December 2011; static models of clinical effectiveness and cost-effectiveness; and dynamic modelling studies to improve parameter estimation and examine effectiveness. SETTING: General population and genitourinary medicine clinic attenders. PARTICIPANTS: Heterosexual women and men. INTERVENTIONS: Traditional partner notification by patient or provider referral, and new partner notification by expedited partner therapy (EPT) or its UK equivalent, accelerated partner therapy (APT). MAIN OUTCOME MEASURES: Population prevalence; index case reinfection; and partners treated per index case. RESULTS: Enhanced partner therapy reduced reinfection in index cases with curable STIs more than simple patient referral [risk ratio (RR) 0.71; 95% confidence interval (CI) 0.56 to 0.89]. There are no randomised trials of APT. The median number of partners treated for chlamydia per index case in UK clinics was 0.60. The number of partners needed to treat to interrupt transmission of chlamydia was lower for casual than for regular partners. In dynamic model simulations, >10% of partners are chlamydia positive with look-back periods of up to 18 months. In the presence of a chlamydia screening programme that reduces population prevalence, treatment of current partners achieves most of the additional reduction in prevalence attributable to partner notification. Dynamic model simulations show that cotesting and treatment for chlamydia and gonorrhoea reduce the prevalence of both STIs. APT has a limited additional effect on prevalence but reduces the rate of index case reinfection. Published quality-adjusted life-year (QALY) weights were of insufficient quality to be used in a cost-effectiveness study of partner notification in this project. Using an intermediate outcome of cost per infection diagnosed, doubling the efficacy of partner notification from 0.4 to 0.8 partners treated per index case was more cost-effective than increasing chlamydia screening coverage. CONCLUSIONS: There is evidence to support the improved clinical effectiveness of EPT in reducing index case reinfection. In a general heterosexual population, partner notification identifies new infected cases but the impact on chlamydia prevalence is limited. Partner notification to notify casual partners might have a greater impact than for regular partners in genitourinary clinic populations. Recommendations for future research are (1) to conduct randomised controlled trials using biological outcomes of the effectiveness of APT and of methods to increase testing for human immunodeficiency virus (HIV) and STIs after APT; (2) collection of HRQL data should be a priority to determine QALYs associated with the sequelae of curable STIs; and (3) standardised parameter sets for curable STIs should be developed for mathematical models of STI transmission that are used for policy-making. FUNDING: The National Institute for Health Research Health Technology Assessment programme
HIV non-B subtype distribution: emerging trends and risk factors for imported and local infections newly diagnosed in South Australia
Monitoring HIV subtype distribution is important for understanding transmission dynamics. Subtype B has
historically been dominant in Australia, but in recent years new clades have appeared. Since 2000, clade data
have been collected as part of HIV surveillance in South Australia. The aim of this study was to evaluate the
prevalence of and risk factors for HIV-1 non-B subtypes. The study population was composed of newly diagnosed,
genotyped HIV subjects in South Australia between 2000 and 2010. We analyzed time trends and subtype
patterns in this cohort; notification data were aggregated into three time periods (2000–2003, 2004–2006, and
2007–2010). Main outcome measures were number of new non-B infections by year, exposure route, and other
demographic characteristics. There were 513 new HIV diagnoses; 425 had information on subtype. The majority
(262/425) were in men who have sex with men (MSM), predominantly subtype B and acquired in Australia.
Infections acquired in Australia decreased from 77% (2000–2003) to 64% (2007–2010) ( p = 0.007) and correspondingly
the proportion of subtype B declined from 85% to 68% ( p = 0.002). Non-B infections were predominantly
(83%) heterosexual contacts, mostly acquired overseas (74%). The majority (68%) of non-B patients
were born outside of Australia. There was a non-significant increase from 1.6% to 4.2% in the proportion of
locally transmitted non-B cases (p = 0.3). Three non-B subtypes and two circulating recombinant forms (CRFs)
were identified: CRF_AE (n = 41), C (n = 36), CRF_AG (n = 13), A (n = 9), and D (n = 2). There has been a substantial
increase over the past decade in diagnosed non-B infections, primarily through cases acquired overseas
Are mice good models for human neuromuscular disease? Comparing muscle excursions in walking between mice and humans
The mouse is one of the most widely used animal models to study neuromuscular diseases and test new therapeutic strategies. However, findings from successful pre-clinical studies using mouse models frequently fail to translate to humans due to various factors. Differences in muscle function between the two species could be crucial but often have been overlooked. The purpose of this study was to evaluate and compare muscle excursions in walking between mice and humans
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