2,648 research outputs found
Diagnosing Sporadic Creutzfeldt-Jakob Disease by the Detection of Abnormal Prion Protein in Patient Urine
IMPORTANCE: Creutzfeldt-Jakob disease (CJD) is a fatal neurodegenerative disorder associated with the accumulation of infectious abnormal prion protein through a mechanism of templated misfolding. A recent report has described the detection of abnormal prion protein in the urine of patients with variant CJD (vCJD) using protein misfolding by cyclic amplification, which was apparently absent in the more common sporadic form of CJD (sCJD). A noninvasive diagnostic test could improve early diagnosis of sCJD and, by screening donations, mitigate the potential risks of prion transmission through human urine–derived pharmaceuticals. Here, we describe the adaptation of the direct detection assay, developed originally as a blood test for vCJD, for the detection of disease-associated prion protein in urine samples from patients with sCJD.
OBJECTIVE: To determine the feasibility of sCJD diagnosis by adaptation of an established vCJD diagnostic blood test to urine.
DESIGN, SETTINGS AND PARTICIPANTS: This retrospective, cross-sectional study included anonymized urine samples from healthy nonneurological control individuals (n = 91), patients with non-prion neurodegenerative diseases (n = 34), and patients with prion disease (n = 37) of which 20 had sCJD. Urine samples obtained during the Medical Research Council PRION-1 Trial, the National Prion Monitoring Cohort Study, and/or referred to the National Prion Clinic or Dementia Research Centre at the National Hospital for Neurology and Neurosurgery in the United Kingdom.
MAIN OUTCOMES AND MEASURES: Presence of sCJD infection determined by an assay that captures, enriches, and detects disease-associated prion protein isoforms.
RESULTS: A total of 162 samples were analyzed, composed of 91 normal control individuals (51 male, 33 female, and 7 not recorded), 34 neurological disease control individuals (19 male and 15 female), and 37 with prion disease (22 male and 15 female). The assay’s specificity for prion disease was 100% (95% CI, 97%-100%), with no false-positive reactions from 125 control individuals, including 34 from a range of neurodegenerative diseases. In contrast to a previous study, which used a different method, sensitivity to vCJD infection was low (7.7%; 95% CI, 0.2%-36%), with only 1 of 13 patients with positive test results, while sensitivity to sCJD was unexpectedly high at 40% (95% CI, 19%-64%).
CONCLUSIONS AND RELEVANCE: We determined 40% of sCJD urine sample results as positive. To our knowledge, this is the first demonstration of an assay that can detect sCJD infection in urine or any target analyte outside of the central nervous system. Urine detection could allow the development of rapid, molecular diagnostics for sCJD and has implications for other neurodegenerative diseases where disease-related assemblies of misfolded proteins might also be present in urine
Numerical Methods for the QCD Overlap Operator: I. Sign-Function and Error Bounds
The numerical and computational aspects of the overlap formalism in lattice
quantum chromodynamics are extremely demanding due to a matrix-vector product
that involves the sign function of the hermitian Wilson matrix. In this paper
we investigate several methods to compute the product of the matrix
sign-function with a vector, in particular Lanczos based methods and partial
fraction expansion methods. Our goal is two-fold: we give realistic comparisons
between known methods together with novel approaches and we present error
bounds which allow to guarantee a given accuracy when terminating the Lanczos
method and the multishift-CG solver, applied within the partial fraction
expansion methods.Comment: 30 pages, 2 figure
Differential expression of synaptophysin and synaptoporin during pre- and postnatal development of the hippocampal network
The closely related synaptic vesicle membrane proteins synaptophysin and synaptoporin are abundant in the hippocampal formation of the adult rat. But the prenatal hippocampal formation contains only synaptophysin, which is first detected at embryonic day 17 (E17) in perikarya and axons of the pyramidal neurons. At E21 synaptophysin immunoreactivity extends into the apical dendrites of these cells and in newly formed terminals contacting these dendrites. The transient presence of synaptophysin in axons and dendrites suggests a functional involvement of synaptophysin in fibre outgrowth of developing pyramidal neurons. Synaptoporin expression parallels the formation of dentate granule cell synaptic contacts with pyramidal neurons: the amount of hippocampal synaptoporin, determined in immunoblots and by synaptoporin immunostaining of developing mossy fibre terminals, increases during the first postnatal week. Moreover, in the adult, synaptoporin is found exclusively in the mossy fibre terminals present in the hilar region of the dentate gyrus and the regio inferior of the cornu ammonis. In contrast, synaptophysin is present in all synaptic fields of the hippocampal formation, including the mossy fibre terminals, where it colocalizes with synaptoporin in the same boutons. Our data indicate that granule neuron terminals differ from all other terminals of the hippocampal formation by the presence of both synaptoporin and synaptophysin. This difference, observed in the earliest synaptic contacts in the postnatal hippocampus and persisting into adult life, suggests distinct functions of synaptoporin in these nerve terminals
Addressing Inequity to Achieve the Maternal and Child Health Millennium Development Goals: Looking Beyond Averages.
Inequity in access to and use of child and maternal health interventions is impeding progress towards the maternal and child health Millennium Development Goals. This study explores the potential health gains and equity impact if a set of priority interventions for mothers and under fives were scaled up to reach national universal coverage targets for MDGs in Tanzania. We used the Lives Saved Tool (LiST) to estimate potential reductions in maternal and child mortality and the number of lives saved across wealth quintiles and between rural and urban settings. High impact maternal and child health interventions were modelled for a five-year scale up, by linking intervention coverage, effectiveness and cause of mortality using data from Tanzania. Concentration curves were drawn and the concentration index estimated to measure the equity impact of the scale up. In the poorest population quintiles in Tanzania, the lives of more than twice as many mothers and under-fives were likely to be saved, compared to the richest quintile. Scaling up coverage to equal levels across quintiles would reduce inequality in maternal and child mortality from a pro rich concentration index of -0.11 (maternal) and -0.12 (children) to a more equitable concentration index of -0,03 and -0.03 respectively. In rural areas, there would likely be an eight times greater reduction in maternal deaths than in urban areas and a five times greater reduction in child deaths than in urban areas. Scaling up priority maternal and child health interventions to equal levels would potentially save far more lives in the poorest populations, and would accelerate equitable progress towards maternal and child health MDGs
The UK Infrared Telescope M33 monitoring project. II. The star formation history in the central square kiloparsec
We have conducted a near-infrared monitoring campaign at the UK InfraRed
Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). The main
aim was to identify stars in the very final stage of their evolution, and for
which the luminosity is more directly related to the birth mass than the more
numerous less-evolved giant stars that continue to increase in luminosity. In
this second paper of the series, we construct the birth mass function and hence
derive the star formation history. The star formation rate has varied between
~0.002 and 0.007 M yr^-1 kpc^-2. We give evidence of two epochs of a
star formation rate enhanced by a factor of a few -- one that happened \geq 6
Gyr ago and produced \geq 80% of the total mass in stars, and one around 250
Myr ago that lasted ~ 200 Myr and formed \leq 6% of the mass in stars. We
construct radial and azimuthal distributions in the image plane and in the
galaxy plane for populations associated with old first-ascent red giant branch
(RGB) stars, intermediate-age Asymptotic Giant Branch (AGB) stars and young
(massive) blue and red supergiants. We find that the RGB stars follow a
spheroidal distribution, while younger stars follow a flat-disc distribution.
The intermediate-age population displays signs of a pseudo-bulge or possibly a
bar. The inner spiral arm pattern as recorded in mid-19^th-century drawings is
confirmed. We interpret our findings as evidence for an old, pressure-supported
component and a younger disc formed 6 Gyr ago, with an accretion event
occurring 250 Myr ago giving rise to the compact nucleus in M33. Our study
provides support for recent Padova stellar evolution models except that
super-AGB stars likely reach low temperatures and thus high mass-loss rates,
supporting the super-AGB nature of the progenitors of dust-enshrouded
supernovae such as SN2008S.Comment: Accepted for publication in MNRA
Dust, pulsation, chromospheres and their role in driving mass loss from red giants in Galactic globular clusters
Context: Mass loss from red giants in old globular clusters affects the
horizontal branch (HB) morphology and post-HB stellar evolution including the
production of ultraviolet-bright stars, dredge up of nucleosynthesis products
and replenishment of the intra-cluster medium. Studies of mass loss in globular
clusters also allows one to investigate the metallicity dependence of the mass
loss from cool, low-mass stars down to very low metallicities.
Aims: We present an analysis of new VLT/UVES spectra of 47 red giants in the
Galactic globular clusters 47 Tuc (NGC 104), NGC 362, omega Cen (NGC 5139), NGC
6388, M54 (NGC 6715) and M15 (NGC 7078). The spectra cover the wavelength
region 6100-9900A at a resolving power of R = 110,000. Some of these stars are
known to exhibit mid-infrared excess emission indicative of circumstellar dust.
Our aim is to detect signatures of mass loss, identify the mechanism(s)
responsible for such outflows, and measure the mass-loss rates.
Methods: We determine for each star its effective temperature, luminosity,
radius and escape velocity. We analyse the H-alpha and near-infrared calcium
triplet lines for evidence of outflows, pulsation and chromospheric activity,
and present a simple model for estimating mass-loss rates from the H-alpha line
profile. We compare our results with a variety of other, independent methods.
Results: We argue that a chromosphere persists in Galactic globular cluster
giants and controls the mass-loss rate to late-K/early-M spectral types, where
pulsation becomes strong enough to drive shock waves at luminosities above the
RGB tip. This transition may be metallicity-dependent. We find mass-loss rates
of ~10^-7 to 10^-5 solar masses per year, largely independent of metallicity.Comment: 23 pages, 17 figures, accepted for publication in Astronomy and
Astrophysic
Abdominal Subcutaneous Adipose Tissue: A Protective Fat Depot?
OBJECTIVE: Obesity is associated with increased metabolic and cardiovascular risk. The ectopic fat hypothesis suggests that subcutaneous fat may be protective, but this theory has yet to be fully explored. RESEARCH DESIGN AND METHODS: Participants from the Framingham Heart Study (n = 3,001, 48.5% women) were stratified by visceral adipose tissue (VAT) into sex-specific tertiles. Within these tertiles, age-adjusted abdominal subcutaneous adipose tissue (SAT) tertiles were examined in relation to cardiometabolic risk factors. RESULTS: In the lowest VAT tertile, risk factor prevalence was low, although systolic blood pressure in women and rates of high triglycerides, impaired fasting glucose, hypertension, and the metabolic syndrome in men increased with increasing SAT tertile (all P < 0.04). In contrast, in the top VAT tertile, lower triglycerides were observed in men with increasing SAT (64.4% high triglycerides in SAT tertile 1 vs. 52.7% in SAT tertile 3, P = 0.03). Similar observations were made for women, although results were not statistically significant (50.6% high triglycerides in SAT tertile 1 vs. 41.0% in tertile 3, P = 0.10). Results in the highest VAT tertile were notable for a lack of increase in the prevalence of low HDL in men and women and in rates of impaired fasting glucose in men with increasing subcutaneous fat, despite sizable differences in BMI across SAT tertiles (27.1 to 36.3 kg/m [women]; 28.1 to 35.7 kg/m [men]). CONCLUSIONS: Although adiposity increases the absolute risk of metabolic and cardiovascular disease, abdominal subcutaneous fat is not associated with a linear increase in the prevalence of all risk factors among the obese, most notably, high triglycerides
Impacts of organic and conventional crop management on diversity and activity of free-living nitrogen fixing bacteria and total bacteria are subsidiary to temporal effects
A three year field study (2007-2009) of the diversity and numbers of the total and metabolically active free-living diazotophic bacteria and total bacterial communities in organic and conventionally managed agricultural soil was conducted at the Nafferton Factorial Systems Comparison (NFSC) study, in northeast England. The result demonstrated that there was no consistent effect of either organic or conventional soil management across the three years on the diversity or quantity of either diazotrophic or total bacterial communities. However, ordination analyses carried out on data from each individual year showed that factors associated with the different fertility management measures including availability of nitrogen species, organic carbon and pH, did exert significant effects on the structure of both diazotrophic and total bacterial communities. It appeared that the dominant drivers of qualitative and quantitative changes in both communities were annual and seasonal effects. Moreover, regression analyses showed activity of both communities was significantly affected by soil temperature and climatic conditions. The diazotrophic community showed no significant change in diversity across the three years, however, the total bacterial community significantly increased in diversity year on year. Diversity was always greatest during March for both diazotrophic and total bacterial communities. Quantitative analyses using qPCR of each community indicated that metabolically active diazotrophs were highest in year 1 but the population significantly declined in year 2 before recovering somewhat in the final year. The total bacterial population in contrast increased significantly each year. Seasonal effects were less consistent in this quantitative study
High prevalence of chronic kidney disease in Iran: a large population-based study
<p>Abstract</p> <p>Background</p> <p>Chronic kidney disease (CKD) is a global public health threat, associated with an alarming increase in morbidity and mortality. The importance is the worldwide increase in its incidence and prevalence.</p> <p>Methods</p> <p>In this cross-sectional study, we estimate the prevalence and determine the associated factors of chronic kidney disease in a representative sample of 10063 participants aged over 20 years, in Tehran, Iran. Chronic kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m2. Glomerular filtration rate was estimated from abbreviated prediction equation provided by the Modification of Diet in Renal Disease study (MDRD).</p> <p>Results</p> <p>Overall prevalence of CKD with the abbreviated MDRD equation was 18.9% (95% confidence interval (CI) 18.2, 20.6). Age adjusted prevalence of CKD was 14.9% (95%CI 14.2, 15.6). Factors associated to CKD include age(years)(odds ratio(OR) 1.1, 95% CI 1.0 to 1.2), female gender (OR 3.1, 95% CI 2.6, 3.7), BMI (BMI 25 to <30 OR 1.5, 95% CI 1.3, 1.8 and BMI ≥ 30 OR 1.6, 95% CI 1.3, 2.0), high waist circumference (OR 1.2, 95% CI 1.1, 1.4), hypertension (OR 1.2, 95% CI 1.1, 1.4), and dyslipidemia (OR 1.3, 95% CI 1.1, 1.5).</p> <p>Conclusion</p> <p>CKD with its high prevalence poses a definite health threat in Iran.</p
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