Orf virus infection causes a contagious pustular dermatitis characterized by extensive vascular changes that have been linked to a virally encoded vascular endothelial growth factor (VEGF). The VEGF ...genes of different strains of orf virus can vary extensively in amino acid sequence. Functional analyses of two major variant VEGF proteins derived from orf virus strains, NZ2 and NZ7, have revealed quantitative differences in biological activities and receptor binding specificities suggesting that these viral VEGFs could have different roles in the pathology of orf virus infection. In this study, we show that both orf virus strains express equivalent levels of the viral VEGF variants and during infection of sheep skin induce comparable levels of vascularization, edema, epidermal rete ridge and scab formation. Recombinants of orf virus NZ2 and NZ7 strains in which the variant VEGF genes were disrupted showed markedly reduced vascular changes and evidence of partially attenuated viral growth. These results demonstrate that despite substantial differences in sequence and biological activity
in vitro, these virally expressed virulence factors are functionally equivalent in their natural host, contributing equally to orf virus pathology.
Though commercial production of polychlorinated biphenyls was banned in the United States in 1977, exposure continues due to their environmental persistence. Several studies have examined the ...association between environmental polychlorinated biphenyl exposure and modulations of the secondary sex ratio, with conflicting results.
Our objective was to evaluate the association between maternal preconceptional occupational polychlorinated biphenyl exposure and the secondary sex ratio.
We examined primipara singleton births of 2595 women, who worked in three capacitor plants at least one year during the period polychlorinated biphenyls were used. Cumulative estimated maternal occupational polychlorinated biphenyl exposure at the time of the infant's conception was calculated from plant-specific job-exposure matrices. A logistic regression analysis was used to evaluate the association between maternal polychlorinated biphenyl exposure and male sex at birth (yes/no).
Maternal body mass index at age 20, smoking status, and race did not vary between those occupationally exposed and those unexposed before the child's conception. Polychlorinated biphenyl-exposed mothers were, however, more likely to have used oral contraceptives and to have been older at the birth of their first child than non-occupationally exposed women. Among 1506 infants liveborn to polychlorinated biphenyl-exposed primiparous women, 49.8% were male; compared to 49.9% among those not exposed (n = 1089). Multivariate analyses controlling for mother's age and year of birth found no significant association between the odds of a male birth and mother's cumulative estimated polychlorinated biphenyl exposure to time of conception.
Based on these data, we find no evidence of altered sex ratio among children born to primiparous polychlorinated biphenyl-exposed female workers.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Atmospheric carbon dioxide concentration (CO2) is increasing, which increases leaf-scale photosynthesis and intrinsic water-use efficiency. These direct responses have the potential to increase plant ...growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of CO2 increase and thus climate change. However, ecosystem CO2-responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a CO2-driven terrestrial carbon sink can appear contradictory. In this work, we synthesise theory and broad, multi-disciplinary evidence for the effects of increasing CO2 (iCO2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre-industry. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2-responses are high in comparison with experiments and theory. Plant mortality and soil carbon iCO2-responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.
The purpose of this clinical study is to determine whether the rate of fracture healing and fracture union, repaired with a locked device, will be as good as or better than standard nonlocking ...bicortical fixation in distal femoral fractures.
Institutional review board-approved, multicenter prospective randomized controlled trial.
Seven level 1 trauma centers across Canada.
Fifty-two patients with distal femoral fractures (AO/OTA 33A1 to 33C2) were enrolled in the randomized trial. Twelve AO/OTA 33C3 fractures were excluded from the randomized trial but followed up as a nonrandomized cohort.
Patients were treated through a standardized minimally invasive approach. Fractures were randomized 1:1 to treatment with the locked Less Invasive Stabilization System (LISS; Synthes, Paoli, PA) or the dynamic condylar screw (DCS). The nonrandomized cohort was treated at the surgeon's discretion.
Primary outcomes were time to radiological union and number of delayed/nonunions at 12 months. Secondary outcomes were postoperative function and complications.
Fifty-two patients were randomized including 34 women and 18 men. The mean age was 59 years. Twenty-eight patients were treated with the LISS and 24 with the DCS. There was no statistically significant difference between the LISS and the DCS in terms of the number of fractures healed, time to union, or functional scores. Complications and revisions were more common in the LISS group. There were 7 reoperations in the LISS group and one in the DCS group. Only 52% of the LISS group healed without intervention by 12 months compared with 91% in the DCS group.
There was no advantage to the locking plate design in the management of distal femoral fractures in this study. The higher cost of the locking plates, challenges in technique, and lack of superiority have led the authors to discontinue the use of this lateral unicortical locking device in favor of other devices that allow locked or nonlocked bicortical fixation, articular compression, and bridging of the comminuted fracture segments. The cost-effective treatment for a subgroup or periarticular fractures may be a fixed-angle nonlocked device in patients with reasonable bone quality.
Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
Observations of the Lyman limit in 19 QSOs Smith, Malcolm G.; Carswell, R. F.; Whelan, J. A. J. ...
Monthly notices of the Royal Astronomical Society,
07/1981, Letnik:
195, Številka:
3
Journal Article
Recenzirano
Odprti dostop
From direct spectroscopic observations of the Lyman-limit region in 32 QSOs, 19 of which are described here, we find that the covering factor for large absorbing clouds in the emission region is ...likely to be $\epsilon\lesssim 0.15$. Under these circumstances, it is unlikely that the mechanism for explaining the low Lyα/Hβ emission-line intensity ratios in QSOs involves significant suppression of Lyα.
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