Abnormal exhaled ethane concentrations in scleroderma

Abstract

Scleroderma (systemic sclerosis) is a chronic multisystem autoimmune disease in which oxidative stress is suspected to play a role in the pathophysiology. Therefore, it was postulated that patients with scleroderma would have abnormally high breath ethane concentrations, which is a volatile product of free-radical-mediated lipid peroxidation, compared with a group of controls. There was a significant difference (p<0.05) between the mean exhaled ethane concentration of 5.27 pmol ml^–1 CO₂ (SEM=0.76) in the scleroderma patients (n=36) versus the mean exhaled concentration of 2.72 pmol ml^?1 CO₂ (SEM=0.71) in a group of healthy controls (n=21). Within the scleroderma group, those subjects taking a calcium channel blocker had lower ethane concentrations compared with patients who were not taking these drugs (p=0.05). There was a significant inverse association between lung diffusion capacity for carbon monoxide (per cent of predicted) and ethane concentration (b=?2.8, p=0.026, CI=?5.2 to ?0.35). These data support the presence of increased oxidative stress among patients with scleroderma that is detected by measuring breath ethane concentrations.     

Ecosystem-Service Tradeoffs Associated with Switching from Annual to Perennial Energy Crops in Riparian Zones of the US Midwest

Integration of energy crops into agricultural landscapes could promote sustainability if they are placed in ways that foster multiple ecosystem services and mitigate ecosystem disservices from existing crops. We conducted a modeling study to investigate how replacing annual energy crops with perennial energy crops along Wisconsin waterways could affect a variety of provisioning and regulating ecosystem services. We found that a switch from continuous corn production to perennial-grass production decreased annual income provisioning by 75%, although it increased annual energy provisioning by 33%, decreased annual phosphorous loading to surface water by 29%, increased below-ground carbon sequestration by 30%, decreased annual nitrous oxide emissions by 84%, increased an index of pollinator abundance by an average of 11%, and increased an index of biocontrol potential by an average of 6%. We expressed the tradeoffs between income provisioning and other ecosystem services as benefit-cost ratios. Benefit-cost ratios averaged 12.06 GJ of additional net energy, 0.84 kg of avoided phosphorus pollution, 18.97 Mg of sequestered carbon, and 1.99 kg of avoided nitrous oxide emissions for every $1,000 reduction in income. These ratios varied spatially, from 2- to 70-fold depending on the ecosystem service. Benefit-cost ratios for different ecosystem services were generally correlated within watersheds, suggesting the presence of hotspots – watersheds where increases in multiple ecosystem services would come at lower-than-average opportunity costs. When assessing the monetary value of ecosystem services relative to existing conservation programs and environmental markets, the overall value of enhanced services associated with adoption of perennial energy crops was far lower than the opportunity cost. However, when we monitized services using estimates for the social costs of pollution, the value of enhanced services far exceeded the opportunity cost. This disparity between recoverable costs and social value represents a fundamental challenge to expansion of perennial energy crops and sustainable agricultural landscapes.     

Assimilation without groups?

In “Origins and Destinations”, Luthra, Soehl and Waldinger aim at “extending the canon” in research on immigrant integration. They do so by studying group and individual level characteristics across a large number of origin groups, thereby replacing group labels with theoretically relevant variables at the group level. In this review, three challenges in this endeavour are discussed: First of all, the analyses do not allow to disentangle the impact of group and individual level characteristics for all variables alike. Secondly, a primary data collection more tailored to the specifics of their conceptual framework is needed. This would many conclusions about how contexts of emigration and immigration truly matter above and beyond individual characteristic on a more solid ground. And third, the authors’ aim to abandon the use of origin group categories in empirical research on immigrant integration may come at a price.     

Structural and biochemical characterization of Rv2140c,a phosphatidylethanolamine-binding protein from Mycobacterium tuberculosis

Rv2140c is one of many conserved Mycobacterium tuberculosis proteins for which no molecular function has been identified. We have determined a high-resolution crystal structure of the Rv2140c gene product, which reveals a dimeric complex that shares strong structural homology with the phosphatidylethanolamine-binding family of proteins. Rv2140c forms low-millimolar interactions with a selection of soluble phosphatidylethanolamine analogs, indicating that it has a role in lipid metabolism. Furthermore, the small molecule locostatin binds to the Rv2140c ligand-binding site and also inhibits the growth of the model organism Mycobacterium smegmatis.     

Backbone and sidechain 1H, 13C and 15N resonance assignments of the RGS domain from human RGS14

We have assigned ¹H, ¹⁵N and ¹³C resonances of the RGS domain from the human RGS14 protein, a multi-domain member of the RGS (Regulators of G-protein signalling) family of proteins, important in the down-regulation of specific G-protein signalling pathways.     

Can environmental flows moderate riparian invasions? The influence of seedling morphology and density on scour losses in experimental floods

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Majority of RNA which co-purifies with unactivated rat hepatic glucocorticoid-receptor complexes is nonspecific and not receptor-associated.

Molybdate-stabilized, unactivated rat hepatic glucocorticoid-receptor complexes were purified by a three-step procedure which includes affinity chromatography, gel filtration and anion exchange chromatography. Following elution of unactivated steroid-receptor complexes from the final DEAE-cellulose column, RNA which remained bound to the anion exchange resin was eluted with 1 M KCl. This RNA was small and heterogeneous in size. Equivalent amounts of RNA were detected after a mock purification which was devoid of receptors, suggesting that the presence of this RNA is not dependent on that of receptors. Both a [32P]DNA complementary to the RNA eluted from DEAE-cellulose and a [32P]DNA probe synthesized from total rat liver RNA gave similar results when hybridized to total rat liver RNA. These data indicated that the RNA which co-purified with unactivated receptors through the first two steps was very similar to total RNA in overall composition. Virtually identical hybridization patterns were also detected when end-labeled probes generated from the DEAE-cellulose eluted RNA or total liver RNA were hybridized to total genomic rat DNA, suggesting that the RNA eluted from the anion exchange resin is not specific or unique. Although these results do not exclude the possibility that there could be specific RNA species associated with the unactivated glucocorticoid receptor, they do indicate that the majority of the RNA eluted from DEAE-cellulose following elution of receptor complexes appears indistinguishable from total rat liver RNA and can be detected in parallel mock purifications.     

Juvenile hormone-like substances can induce vitellogenesis in the tick Ornithodoros moubata (Acarina: Argasidae)

Topical application of different juvenile hormone analogs (JHA) or of a mixture of stereoisomers of insect juvenile hormone (JH) 1 and 3 to fed virgin female Ornithodoros moubata immediately after feeding induced vitellogenesis and egg-laying in up to 70% of treated females. In controls only 13.7% oviposited. The eggs were sterile, with abnormal shape, but their number versus the weight of engorged females was normal or sometimes greater than in mated females. However, preoviposition period was longer than in mated females.

It was more difficult to induce egg-laying by similar topical applications 100 days after feeding of virgin females. A maximum of 58% of ovipositing females was obtained with a very high dosage of JH mixture (500 fig). Injection of this mixture into the females was more potent; 15 to 50 fig induced oviposition in about 60% of the females. The preoviposition period was also longer than in control females.

Our results suggest the presence of a JH-like substance which is involved in the hormonal control of vitellogenesis. However, since natural isomers of JH were much less efficient than isomeric mixtures or JHA, we suppose that the natural tick hormone does not correspond to JH, but rather to a JH-like substance.     

Ecdysteroids in females and eggs of the Ixodid tick Amblyomma hebraeum

Summary

A mated Amblyomma hebraeum female will engorge on a host for about 8 days before detaching and beginning the maturation of its single egg batch which is laid during a period of about 30 days. The feeding period is characterized by an important synthesis of endocuticular material occurring before the rapid feeding phase. This latter phase, correlated with an enormous weight uptake, shows an increase of ecdysteroid levels measured in the whole animal by RIA. However, the hemolymphatic levels of ecdysteroids remain very low (12 pg 20-hydroxyecdysone equivalent (20-OH-E eq.) per μ1. Within 4 days after detachment, the salivary glands degenerate. Ecdysteroid levels in the whole animal continue to increase, reaching high values (about 500 ng 20-OH-E eq./tick) at the moment of oviposition which begins 10–14 days after dropping. During the same period, hemolymphatic ecdysteroid levels increase, rising to a peak (600 pg 20-OH-E eq./μ1) 1 day prior to the beginning of oviposition. Then, the levels decrease and stabilize around 250 pg 20-OH-E eq./μl during egg-laying. Freshly laid eggs contain large amounts of ecdysteroids (2744 pg 20-OH-E eq./mg).

20-Hydroxyecdysone and ecdysone have been found to be the major free ecdysteroids in hemolymph, ovaries and eggs (verified by the HPLC-RIA technique and GC-MF of silylated HPLC fractions). Helix juice (or esterase) labile ecdysteroid conjugates do not seem to be present to any noticeable extent in hemolymph, ovaries and eggs.