304 research outputs found
Methylene tetrahydrofolate reductase, transforming growth factor-ÎČ1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis
AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-ÎČ1 (TGF-ÎČ1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-ÎČ1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population
Polimorfismos dos genes metilenotetrahidrofolato redutase, fator de crescimento transformador ÎČ1 e linfotoxinaâα e susceptibilidade Ă artrite reumatoide
ResumoAntecedentesA artrite reumatoide Ă© uma doença autoimune amplamente prevalente com sugerida predisposição genĂ©tica.ObjetivosDetectar o padrĂŁo de polimorfismo dos genes metilenotetrahidrofolato redutase (MTHFR C677T e A1298C), fator de crescimento transformador ÎČ1 (TGFâÎČ1 T869C) e linfotoxinaâα (LTâα A252G) em pacientes com artrite reumatoide e correlacionar esses padrĂ”es com a atividade da doença e os nĂveis sĂ©ricos de fator de necrose tumoral alfa (TNFâα), fator ativador de linfĂłcitos B (BAFF) e osteopontina.MĂ©todosForam genotipados 194 indivĂduos â 90 controles e 104 com artrite reumatoide â Ă procura de polimorfismos dos genes MTHFR C677T e A1298C, TGFâÎČ1 T869C e LTâα A252G com uma metodologia baseada na PCRâRFLP. Mensuraramâse tambĂ©m os nĂveis sĂ©ricos de TNFâα, osteopontina e BAFF com kits de Elisa.ResultadosO genĂłtipo CT e o alelo T do MTHFR C677T e o genĂłtipo GG e alelo G do LTâα A252G estĂŁo associados ao risco de AR e a nĂveis mais elevados da citocina prĂłâinflamatĂłria TNFâα em pacientes com artrite reumatoide.ConclusĂŁoOs achados do presente estudo sugerem que hĂĄ associação entre os polimorfismos dos genes MTHFR C677T e LTâα A252G e um risco aumentado de AR nessa amostra da população egĂpcia.AbstractBackgroundRheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition.ObjectivesThe aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677T and A1298C), transforming growth factorâÎČ1 (TGFâÎČ1 T869C) and lymphotoxinâα (LTâα A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factorâalpha (TNFâα), BâCell Activating Factor (BAFF), and osteopontin.MethodsA total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677T and A1298C, TGFâÎČ1 T869C and LTâα A252G polymorphisms using a methodology based on PCRâRFLP. Also serum levels of TNFâα, osteopontin and BAFF were measured by ELISA kits.ResultsThe CT genotype and T allele of MTHFR C677T and GG genotype and G allele of LTâα A252G are associated with the risk of RA and with higher levels of the proâinflammatory cytokine, TNFâα in patients with rheumatoid arthritis.ConclusionOur findings suggest that there is association between MTHFR C677T and LTâα A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population
The Pearson-Readhead Survey of Compact Extragalactic Radio Sources From Space. II. Analysis of Source Properties
We have performed a multi-dimensional correlation analysis on the observed
properties of a statistically complete core-selected sample of compact
radio-loud active galactic nuclei, based on data from the VLBI Space Observing
Programme (Paper I) and previously published studies. Our sample is drawn from
the well-studied Pearson-Readhead (PR) survey, and is ideally suited for
investigating the general effects of relativistic beaming in compact radio
sources. In addition to confirming many previously known correlations, we have
discovered several new trends that lend additional support to the beaming
model. These trends suggest that the most highly beamed sources in
core-selected samples tend to have a) high optical polarizations; b) large
pc/kpc-scale jet misalignments; c) prominent VLBI core components; d)
one-sided, core, or halo radio morphology on kiloparsec scales; e) narrow
emission line equivalent widths; and f) a strong tendency for intraday
variability at radio wavelengths. We have used higher resolution space and
ground-based VLBI maps to confirm the bi-modality of the jet misalignment
distribution for the PR survey, and find that the sources with aligned parsec-
and kiloparsec-scale jets generally have arcsecond-scale radio emission on both
sides of the core. The aligned sources also have broader emission line widths.
We find evidence that the BL Lacertae objects in the PR survey are all highly
beamed, and have very similar properties to the high-optically polarized
quasars, with the exception of smaller redshifts. A cluster analysis on our
data shows that after partialing out the effects of redshift, the luminosities
of our sample objects in various wave bands are generally well-correlated with
each other, but not with other source properties.Comment: 21 pages, 10 figures. Accepted for publication in the Astrophysical
Journal. Part I can be found at astro-ph/010227
Measuring the brightness temperature distribution of extragalactic radio sources with space VLBI
We have used VSOP space very long baseline interferometry observations to
measure the brightness temperature distribution of a well-defined sub-set of
the Pearson-Readhead sample of extragalactic radio sources. VLBI which is
restricted to Earth-diameter baselines is not generally sensitive to emitting
regions with brightness temperatures greater than approximately K,
coincidentally close to theoretical estimates of brightness temperature limits,
K. We find that a significant proportion of our sample have
brightness temperatures greater than K; many have unresolved
components on the longest baselines, and some remain completely unresolved.
These observations begin to bridge the gap between the extended jets seen with
ground-based VLBI and the microarcsecond structures inferred from intraday
variability, evidenced here by the discovery of a relationship between intraday
variability and VSOP-measured brightness temperature, likely due to the effects
of relativistic beaming. Also, lower limits on jet Lorentz factors, estimated
from space VLBI observations, are starting to challenge numerical simulations
that predict low Lorentz factor jets.Comment: 4 pages + 1 figure, ApJ letters, accepte
Discovery of the Galaxy Proximity Effect and Implications for Measurements of the Ionizing Background Radiation at Low Redshifts
We present an analysis of galaxy and QSO absorption line pairs toward 24 QSOs
at redshifts between z~0.2 and 1 in an effort to establish the relationship
between galaxies and absorption lines in physical proximity to QSOs. We
demonstrate the existence of a galaxy proximity effect, in that galaxies in the
vicinities of QSOs do not show the same incidence and extent of gaseous
envelopes as galaxies far from QSOs. We show that the galaxy proximity effect
exists to galaxy-QSO velocity separations of ~ 3000 km/s, much larger than the
size of a typical cluster (~ 1000 km/s), i.e. it is more comparable to the
scale of the sphere of influence of QSO ionizing radiation rather than the
scale of galaxy-QSO clustering. This indicates that the QSO ionizing radiation
rather than some dynamical effect from the cluster environment is responsible
for the galaxy proximity effect. We combine previous findings that (1) many or
most Lya absorption lines arise in extended galaxy envelopes, and (2) galaxies
cluster around QSOs to show that the magnitude of the Lya forest proximity
effect is underestimated. Consequently, determinations of the UV ionizing
background intensity using the proximity effect are likely overestimated. We
use the galaxy-QSO cross-correlation function measured from our data to
estimate the magnitude of this overestimate and find that it could be as high
as a factor of 20 at z<1. This can have strong implications for models of the
origin and evolution of the ionizing background, and may indicate that QSOs
produce sufficient ionizing flux at all redshifts to account for the entire
background radiation field.Comment: 26 pages, 3 figures, to appear in ApJ, October 20, 200
Cross-species complementation reveals conserved functions for EARLY FLOWERING 3 between monocots and dicots
Plant responses to the environment are shaped by external stimuli and internal signaling pathways. In both the model plant Arabidopsis thaliana (Arabidopsis) and crop species, circadian clock factors are critical for growth, flowering, and circadian rhythms. Outside of Arabidopsis, however, little is known about the molecular function of clock gene products. Therefore, we sought to compare the function of Brachypodium distachyon (Brachypodium) and Setaria viridis (Setaria) orthologs of EARLY FLOWERING 3, a key clock gene in Arabidopsis. To identify both cycling genes and putative ELF3 functional orthologs in Setaria, a circadian RNA-seq dataset and online query tool (Diel Explorer) were generated to explore expression profiles of Setaria genes under circadian conditions. The function of ELF3 orthologs from Arabidopsis, Brachypodium, and Setaria was tested for complementation of an elf3 mutation in Arabidopsis. We find that both monocot orthologs were capable of rescuing hypocotyl elongation, flowering time, and arrhythmic clock phenotypes. Using affinity purification and mass spectrometry, our data indicate that BdELF3 and SvELF3 could be integrated into similar complexes in vivo as AtELF3. Thus, we find that, despite 180 million years of separation, BdELF3 and SvELF3 can functionally complement loss of ELF3 at the molecular and physiological level
Electrical transport between epitaxial manganites and carbon nanotubes
The possibility of performing spintronics at the molecular level may be
realized in devices that combine fully spin polarized oxides such as manganites
with carbon nanotubes. However, it is not clear whether electrical transport
between such different material systems is viable. Here we show that the room
temperature conductance of manganite-nanotube-manganite devices is only half
the value recorded in similar palladium-nanotube-palladium devices.
Interestingly, the former shows a pseudogap in the conductivity below the
relatively high temperature of 200 K. Our results suggest the possibility of
new spintronics heterostructures that exploit fully spin polarized sources and
drains
Safely managed hygiene : a risk-based assessment of handwashing water quality
Sustainable Development Goal (SDG) Indicator 6.2.1 requires household handwashing facilities to have soap and water, but there are no guidelines for handwashing water quality. In contrast, drinking water quality guidelines are defined: water must be "free from contamination" to be defined as "safely managed" (SDG Indicator 6.1.1). We modeled the hypothesized mechanism of infection due to contaminated handwashing water to inform risk-based guidelines for microbial quality of handwashing water. We defined two scenarios that should not occur: (1) if handwashing caused fecal contamination, indicated using Escherichia coli, on a person's hands to increase rather than decrease and (2) if hand-to-mouth contacts following handwashing caused an infection risk greater than an acceptable threshold. We found water containing <1000 E. coli colony-forming units (CFU) per 100 mL removes E. coli from hands with>99.9% probability. However, for the annual probability of infection to be <1:1000, handwashing water must contain <2 Ă 10; -6; focus-forming units of rotavirus, <1 Ă 10; -4; CFU of Vibrio cholerae, and <9 Ă 10; -6; Cryptosporidium oocysts per 100 mL. Our model suggests that handwashing with nonpotable water will generally reduce fecal contamination on hands but may be unable to lower the annual probability of infection risks from hand-to-mouth contacts below 1:1000
Estimating Surface Area in Early Hominins
Height and weight-based methods of estimating surface area have played an important role in the development of the current consensus regarding the role of thermoregulation in human evolution. However, such methods may not be reliable when applied to early hominins because their limb proportions differ markedly from those of humans. Here, we report a study in which this possibility was evaluated by comparing surface area estimates generated with the best-known height and weight-based method to estimates generated with a method that is sensitive to proportional differences. We found that the two methods yield indistinguishable estimates when applied to taxa whose limb proportions are similar to those of humans, but significantly different results when applied to taxa whose proportions differ from those of humans. We also found that the discrepancy between the estimates generated by the two methods is almost entirely attributable to inter-taxa differences in limb proportions. One corollary of these findings is that we need to reassess hypotheses about the role of thermoregulation in human evolution that have been developed with the aid of height and weight-based methods of estimating body surface area. Another is that we need to use other methods in future work on fossil hominin body surface areas
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