2,908 research outputs found
Murine lymphoid procoagulant activity induced by bacterial lipopolysaccharide and immune complexes is a monocyte prothrombinase
Murine lymphoid cells respond rapidly to bacterial lipopolysaccharide or antigen-antibody complexes to initiate or accelerate the blood coagulation pathways. The monocyte or macrophage has been identified as the cellular source, although lymphocyte collaboration is required for the rapid induction of the procoagulant response. This procoagulant activity is identified in the present study as a direct prothrombin activator, i.e., a prothrombinase. Studies with plasmas deficient in single coagulation factors demonstrate that the induced murine procoagulant activity effector molecule does not require factors XII, VIII, VII, X, or V, but does require prothrombin to transform fibrinogen to fibrin. This enzyme(s) produces limited proteolysis of prothrombin to yield thrombin or thrombinlike products that are functionally capable of converting fibrinogen to fibrin. The prothrombinase is undetectable in freshly isolated Murine lymphoid cells respond rapidly to bacterial lipopolysaccharide or antigen-antibody complexes to initiate or accelerate the blood coagulation pathways. The monocyte or macrophage has been identified as the cellular source, although lymphocyte collaboration is required for the rapid induction of the procoagulant response. This procoagulant activity is identified in the present study as a direct prothrombin activator, i.e., a prothrombinase. Studies with plasmas deficient in single coagulation factors demonstrate that the induced murine procoagulant activity effector molecule does not require factors XII, VIII, VII, X, or V, but does require prothrombin to transform fibrinogen to fibrin. This enzyme(s) produces limited proteolysis of prothrombin to yield thrombin or thrombinlike products that are functionally capable of converting fibrinogen to fibrin. The prothrombinase is undetectable in freshly isolate
Membrane-containing virus particles exhibit the mechanics of a composite material for genome protection
The protection of the viral genome during extracellular transport is an absolute requirement for virus survival and replication. In addition to the almost universal proteinaceous capsids, certain viruses add a membrane layer that encloses their double-stranded (ds) DNA genome within the protein shell. Using the membrane-containing enterobacterial virus PRD1 as a prototype, and a combination of nanoindentation assays by atomic force microscopy and finite element modelling, we show that PRD1 provides a greater stability against mechanical stress than that achieved by the majority of dsDNA icosahedral viruses that lack a membrane. We propose that the combination of a stiff and brittle proteinaceous shell coupled with a soft and compliant membrane vesicle yields a tough composite nanomaterial well-suited to protect the viral DNA during extracellular transport
Ultrastructural pathology of nephropathies with organized deposits: a case series
Renal organized or structured deposits are much less frequent than those with usual type immunocomplex deposits and are encountered in a wide variety of primary and systemic disorders. It has been suggested that immunoglobulins (Igs) are responsible for organized deposits. We report 5 cases who have been diagnosed and treated in our hospital. Patients were aged 52 to 72 years, three of them were males and had variable degree of renal function, from normal serum creatinine to uraemia. Proteinuria was detected in all patients while monoclonal component was present only in the serum of one subject. Ultrastructural analysis of renal specimens revealed organized deposits. Diagnoses that were made are the following: membranoproliferative glomerulonephritis with finger print, immunotactoid glomerulopathy, membranoproliferative glomerulonephritis with arched deposits, primary amyloidosis and light chain deposition disease. In systemic disorders ultrastructural pathology could be particularly valuable for correct deposits classification, precise localization and pattern of deposition of Igs
Acute and Chronic Effects of Particles on Hospital Admissions in New-England
Background: Many studies have reported significant associations between exposure to and hospital admissions, but all have focused on the effects of short-term exposure. In addition all these studies have relied on a limited number of monitors in their study regions, which introduces exposure error, and excludes rural and suburban populations from locations in which monitors are not available, reducing generalizability and potentially creating selection bias. Methods Using our novel prediction models for exposure combining land use regression with physical measurements (satellite aerosol optical depth) we investigated both the long and short term effects of exposures on hospital admissions across New-England for all residents aged 65 and older. We performed separate Poisson regression analysis for each admission type: all respiratory, cardiovascular disease (CVD), stroke and diabetes. Daily admission counts in each zip code were regressed against long and short-term exposure, temperature, socio-economic data and a spline of time to control for seasonal trends in baseline risk. Results: We observed associations between both short-term and long-term exposure to and hospitalization for all of the outcomes examined. In example, for respiratory diseases, for every10-µg/m increase in short-term exposure there is a 0.70 percent increase in admissions (CI = 0.35 to 0.52) while concurrently for every10-µg/m increase in long-term exposure there is a 4.22 percent increase in admissions (CI = 1.06 to 4.75). Conclusions: As with mortality studies, chronic exposure to particles is associated with substantially larger increases in hospital admissions than acute exposure and both can be detected simultaneously using our exposure models
Determining the best method for first-line assessment of neonatal blood glucose levels
Objective: To evaluate and compare the accuracy and performance of two electrochemical glucose meters. To determine the user acceptability of these glucose meters and the ABL 620 Blood Gas Analyser (Radiometer, Copenhagen, Denmark) with an electrochemical glucose oxidase electrode for use in a Level 2 special care baby unit
Statistically derived contributions of diverse human influences to twentieth-century temperature changes
The warming of the climate system is unequivocal as evidenced by an increase in global temperatures by 0.8 °C over the past century. However, the attribution of the observed warming to human activities remains less clear, particularly because of the apparent slow-down in warming since the late 1990s. Here we analyse radiative forcing and temperature time series with state-of-the-art statistical methods to address this question without climate model simulations. We show that long-term trends in total radiative forcing and temperatures have largely been determined by atmospheric greenhouse gas concentrations, and modulated by other radiative factors. We identify a pronounced increase in the growth rates of both temperatures and radiative forcing around 1960, which marks the onset of sustained global warming. Our analyses also reveal a contribution of human interventions to two periods when global warming slowed down. Our statistical analysis suggests that the reduction in the emissions of ozone-depleting substances under the Montreal Protocol, as well as a reduction in methane emissions, contributed to the lower rate of warming since the 1990s. Furthermore, we identify a contribution from the two world wars and the Great Depression to the documented cooling in the mid-twentieth century, through lower carbon dioxide emissions. We conclude that reductions in greenhouse gas emissions are effective in slowing the rate of warming in the short term.F.E. acknowledges financial support from the Consejo Nacional de Ciencia y Tecnologia (http://www.conacyt.gob.mx) under grant CONACYT-310026, as well as from PASPA DGAPA of the Universidad Nacional Autonoma de Mexico. (CONACYT-310026 - Consejo Nacional de Ciencia y Tecnologia; PASPA DGAPA of the Universidad Nacional Autonoma de Mexico
Particulate air pollution and survival in a COPD cohort
<p>Abstract</p> <p>Background</p> <p>Several studies have shown cross-sectional associations between long term exposure to particulate air pollution and survival in general population or convenience cohorts. Less is known about susceptibility, or year to year changes in exposure. We investigated whether particles were associated with survival in a cohort of persons with COPD in 34 US cities, eliminating the usual cross-sectional exposure and treating PM<sub>10 </sub>as a within city time varying exposure.</p> <p>Methods</p> <p>Using hospital discharge data, we constructed a cohort of persons discharged alive with chronic obstructive pulmonary disease using Medicare data between 1985 and 1999. 12-month averages of PM<sub>10 </sub>were merged to the individual annual follow up in each city. We applied Cox's proportional hazard regression model in each city, with adjustment for individual risk factors.</p> <p>Results</p> <p>We found significant associations in the survival analyses for single year and multiple lag exposures, with a hazard ratio for mortality for an increase of 10 μg/m<sup>3 </sup>PM<sub>10 </sub>over the previous 4 years of 1.22 (95% CI: 1.17–1.27).</p> <p>Conclusion</p> <p>Persons discharged alive for COPD have substantial mortality risks associated with exposure to particles. The risk is evident for exposure in the previous year, and higher in a 4 year distributed lag model. These risks are significantly greater than seen in time series analyses.</p
Socioeconomic considerations in the health of urban areas
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45780/1/11524_2006_Article_BF02345090.pd
Disorder Effects on Exciton-Polariton Condensates
The impact of a random disorder potential on the dynamical properties of Bose
Einstein condensates is a very wide research field. In microcavities, these
studies are even more crucial than in the condensates of cold atoms, since
random disorder is naturally present in the semiconductor structures. In this
chapter, we consider a stable condensate, defined by a chemical potential,
propagating in a random disorder potential, like a liquid flowing through a
capillary. We analyze the interplay between the kinetic energy, the
localization energy, and the interaction between particles in 1D and 2D
polariton condensates. The finite life time of polaritons is taken into account
as well. In the first part, we remind the results of [G. Malpuech et al. Phys.
Rev. Lett. 98, 206402 (2007).] where we considered the case of a static
condensate. In that case, the condensate forms either a glassy insulating phase
at low polariton density (strong localization), or a superfluid phase above the
percolation threshold. We also show the calculation of the first order spatial
coherence of the condensate versus the condensate density. In the second part,
we consider the case of a propagating non-interacting condensate which is
always localized because of Anderson localization. The localization length is
calculated in the Born approximation. The impact of the finite polariton life
time is taken into account as well. In the last section we consider the case of
a propagating interacting condensate where the three regimes of strong
localization, Anderson localization, and superfluid behavior are accessible.
The localization length is calculated versus the system parameters. The
localization length is strongly modified with respect to the non-interacting
case. It is infinite in the superfluid regime whereas it is strongly reduced if
the fluid flows with a supersonic velocity.Comment: chapter for a book "Exciton Polaritons in Microcavities: New
Frontiers" by Springer (2012), the original publication is available at
http://www.springerlink.co
Low-level environmental lead exposure in childhood and adult intellectual function: a follow-up study
<p>Abstract</p> <p>Background</p> <p>Early life lead exposure might be a risk factor for neurocognitive impairment in adulthood.</p> <p>Objectives</p> <p>We sought to assess the relationship between early life environmental lead exposure and intellectual function in adulthood. We also attempted to identify which time period blood-lead concentrations are most predictive of adult outcome.</p> <p>Methods</p> <p>We recruited adults in the Boston area who had participated as newborns and young children in a prospective cohort study that examined the relationship between lead exposure and childhood intellectual function. IQ was measured using the Wechsler Abbreviated Scale of Intelligence (WASI). The association between lead concentrations and IQ scores was examined using linear regression.</p> <p>Results</p> <p>Forty-three adults participated in neuropsychological testing. Childhood blood-lead concentration (mean of the blood-lead concentrations at ages 4 and 10 years) had the strongest relationship with Full-Scale IQ (β = -1.89 ± 0.70, p = 0.01). Full-scale IQ was also significantly related to blood-lead concentration at age 6 months (β = -1.66 ± 0.75, p = 0.03), 4 years (β = -0.90 ± 0.41, p = 0.03) and 10 years (β = -1.95 ± 0.80, p = 0.02). Adjusting for maternal IQ altered the significance of the regression coefficient.</p> <p>Conclusions</p> <p>Our study suggests that lead exposure in childhood predicts intellectual functioning in young adulthood. Our results also suggest that school-age lead exposure may represent a period of increased susceptibility. Given the small sample size, however, the potentially confounding effects of maternal IQ cannot be excluded and should be evaluated in a larger study.</p
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