This paper addresses the effects of gaseous nitric acid (HNO3) and ozone (O3), two important air pollutants, on six lichen species with different morphological, ecological, and biological ...characteristics. The treatment chambers were set up in a factorial design consisting of control chambers, chambers fumigated with HNO3, with O3, and with HNO3 and O3, together. Each species showed a different sensitivity to the fumigations, reflecting the physiological variation among species. Our results clearly indicate that HNO3 is a strong phytotoxin to many lichens, and that O3 alone has little effect on the measured parameters. The combined fumigation effects of HNO3 and O3 were not significantly different from HNO3 alone.
► We fumigated 6 lichen species with factorial combinations of nitric acid (HNO3) and ozone (O3). ► Some species were highly sensitive to HNO3 while others were tolerant. ► No species responded significantly to O3. ► The combined fumigation effects of HNO3 and O3 were not significantly different from HNO3 alone. ► HNO3 may play an important role in lichen community composition in areas with high HNO3 pollution.
Nitric acid can be highly toxic to lichens through several physiological mechanisms. Ozone is relatively non-toxic to fumigated lichens.
Professional dancers represent a unique patient population in the setting of hip arthroplasty, given the high degree of hip strength and mobility required by their profession. We sought to determine ...the clinical outcomes and ability to return to professional dance after total hip arthroplasty (THA) or hip resurfacing arthroplasty (HRA).
Active professional dancers who underwent primary THA or HRA at a single institution with minimum one-year follow-up were included in the study. Primary outcomes included the rate of return to professional dance, three patient-reported outcome measures (PROMs) (modified Harris Hip Score (mHHS), Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), and Lower Extremity Activity Scale (LEAS)), and postoperative complications.
A total of 49 hips in 39 patients (mean age 56 years (SD 13); 80% female (n = 39)) were included. Mean follow-up was 4.9 years (SD 5.1). Of these 49 hips, 37 THAs and 12 HRAs were performed. In all, 96% of hips returned to professional dance activities postoperatively. With regard to PROMs, there were statistically significant improvements in mHHS, HOOS-JR, and LEAS from baseline to ≥ one year postoperatively. There were complications in 7/49 hips postoperatively (14%), five of which required revision surgery (10%). There were no revisions for instability after the index procedure. Two complications (5.4%) occurred in hips that underwent THA compared with five (42%) after HRA (p = 0.007), though the difference by procedure was not significantly different when including only contemporary implant designs (p = 0.334).
Active professional dancers experienced significant improvements in functional outcome scores after THA or HRA, with a 96% rate of return to professional dance. However, the revision rate at short- to mid-term follow-up highlights the challenges of performing hip arthroplasty in this demanding patient population. Further investigation is required to determine the results of THA versus HRA using contemporary implant designs in these patients.
Epiphytic lichen communities are highly sensitive to excess nitrogen (N), which causes the replacement of native floras by N-tolerant, "weedy" eutrophic species. This shift is commonly used as the ...indicator of ecosystem "harm" in studies developing empirical critical levels (CLE) for ammonia (NH
3
) and critical loads (CLO) for N. To be most effective, empirical CLE and/or CLO must firmly link lichen response to causal pollutant(s), which is difficult to accomplish in field studies in part because the high cost of N measurements limits their use. For this case study we synthesized an unprecedented array of atmospheric N measurements across 22 long-term monitoring sites in the Los Angeles Basin, California, USA: gas concentrations of NH
3
, nitric acid (HNO
3
), nitrogen dioxide, and ozone (
n
= 10 sites); N deposition in throughfall (
n
= 8 sites); modeled estimates of eight different forms of N (
n
= 22 sites); and nitrate deposition accumulated on oak twigs (
n
= 22 sites). We sampled lichens on black oak (
Quercus kelloggii
Newb.), and scored plots using two indices of eutroph (N tolerant species) abundance to characterize the community-level response to N. Our results contradict two common assertions about the lichen-N response: (1) that eutrophs respond specifically to NH
3
and (2) that the response necessarily depends upon the increased pH of lichen substrates. Eutroph abundance related significantly but weakly to NH
3
(
r
2
= 0.48). Total N deposition as measured in canopy throughfall was by far the best predictor of eutroph abundance (
r
2
= 0.94), indicating that eutrophs respond to multiple forms of N. Most N variables had significant correlations to eutroph abundance (
r
2
= 0.36-0.62) as well as to each other (
r
2
= 0.61-0.98), demonstrating the risk of mistaken causality in CLE/CLO field studies that lack sufficient calibration data. Our data furthermore suggest that eutroph abundance is primarily driven by N inputs, not substrate pH, at least at the high-pH values found in the basin (4.8-6.1). Eutroph abundance correlated negatively with trunk bark pH (
r
2
= 0.43), exactly the opposite of virtually all previous studies of eutroph behavior. This correlation probably results because HNO
3
dominates N deposition in our study region.
A passive sampler for collection of gaseous nitric acid (HNO
3) and nitrous acid (HNO
2) is based on a diffusion of ambient air through Teflon membrane and absorption of the pollutants on Nylasorb ...nylon filter. The sampler is simple in design, easy to make, inexpensive and resistant to harsh weather conditions. The sampler has been calibrated against honeycomb denuder systems in ambient southern California air and in controlled HNO
3 exposures. It is more precise than the old open-face HNO
3 sampler. It can measure wide ranges of ambient HNO
2 and HNO
3 concentrations for extended periods of time and can be used for regional-scale monitoring of the pollutants.
Natural ecosystems globally are often subject to multiple human disturbances that are difficult to restore. A restoration experiment was done in an urban fragment of native coastal sage scrub ...vegetation in Riverside, California that has been subject to frequent fire, high anthropogenic nitrogen deposition, and invasion by Mediterranean annual weeds. Hand cultivation and grass‐specific herbicide were both successful in controlling exotic annual grasses and promoting establishment of seeded coastal sage scrub vegetation. There was no native seedbank left at this site after some 30 years of conversion to annual grassland, and the only native plants that germinated were the seeded shrubs, with the exception of one native summer annual. The city green‐waste mulch used in this study (C:N of 39:1) caused short‐term N immobilization but did not result in decreased grass density or increased native shrub establishment. Seeding native shrubs was successful in a wet year in this Mediterranean‐type climate but was unsuccessful in a dry year. An accidental spring fire did not burn first‐year shrubs, although adjacent plots dominated by annual grass did burn. The shrubs continued to exclude exotic grasses into the second growing season, suggesting that successful shrub establishment may reduce the frequency of the fire return interval.
The deposition of nitrogenous pollutants has serious implications for ecosystem function and stability. Research in temperate ecosystems has indicated a wide range of ecological responses, yet very ...little is known about arid ecosystems. In this study, measurements of atmospheric and soil concentrations of the plant-available NO
-
3 and NH
+
4 were evaluated to identify a potential gradient in nitrogen (N) deposition. The evaluations were conducted in coastal sage scrub, a semi-arid vegetation type native to the lower elevations of southern California.
The summer atmospheric concentrations of nitrate (NO
-
3) and ammonium (NH
+
4) were determined at five locations on the Perris Plain of southern California. The atmospheric influences varied from direct interception of pollution generated in the Los Angeles Basin at the northern end of the gradient to a site 70
km south lacking any direct Los Angeles influence. The summer atmospheric concentrations of NO
-
3 varied more than three-fold along the gradient. Ammonium concentrations followed a similar pattern, but the gradient was less steep. Winter concentrations were very low for both compounds. The summer soil surface NO
-
3 concentrations were near the detection limits at low pollution sites but in the range of 50–60
μg
N
g
-1 soil under highly polluted conditions. Wet deposition was found to be a minor contributor of plant-available N, suggesting that dry deposition may be a consequential source of plant-available N.
The detection of significant changes in inorganic, plant-available N in the upper layer of soils is enhanced by the unique environmental conditions and vegetation of southern California. This study suggests that the coastal sage scrub ecosystem is experiencing significant changes in N fertility that may contribute to changes in plant species composition. The data also show that this semi-arid ecosystem provides a unique opportunity to assess many physical, chemical and biological responses to dry deposition alone.
Epstein–Barr virus (EBV) encodes for several enzymes that are involved in viral DNA replication. There is evidence that some viral proteins, by themselves, can induce immune dysregulation that may ...contribute to the pathophysiology of the virus infection. In this study, we focused on the EBV-encoded deoxyuridine triphosphate nucleotidohydrolase (dUTPase) and present the first evidence that the dUTPase is able to induce immune dysregulation in vitro as demonstrated by the inhibition of the replication of stimulated peripheral blood mononuclear cells (PBMCs) and the upregulation of several proinflammatory cytokines including TNF-α, IL-1β, IL-8, IL-6, and IL-10 produced by unstimulated PBMCs treated with purified EBV-encoded dUTPase. Depletion of CD14-positive cells (monocytes) eliminated the cytokine profile induced by EBV dUTPase treatment. The data support the hypothesis that at least one protein of the EBV early antigen complex can induce immune dysregulation and may be involved in the pathophysiology of EBV-associated disease.
Frameworks for limiting ecosystem exposure to excess nutrients and acidity require accurate and complete deposition budgets of reactive nitrogen (Nr). While much progress has been made in developing ...total Nr deposition budgets for the U.S., current budgets remain limited by key data and knowledge gaps. Analysis of National Atmospheric Deposition Program Total Deposition (NADP/TDep) data illustrates several aspects of current Nr deposition that motivate additional research. Averaged across the continental U.S., dry deposition contributes slightly more (55%) to total deposition than wet deposition and is the dominant process (>90%) over broad areas of the Southwest and other arid regions of the West. Lack of dry deposition measurements imposes a reliance on models, resulting in a much higher degree of uncertainty relative to wet deposition which is routinely measured. As nitrogen oxide (NOx) emissions continue to decline, reduced forms of inorganic nitrogen (NHx = NH3 + NH4+) now contribute >50% of total Nr deposition over large areas of the U.S. Expanded monitoring and additional process-level research are needed to better understand NHx deposition, its contribution to total Nr deposition budgets, and the processes by which reduced N deposits to ecosystems. Urban and suburban areas are hotspots where routine monitoring of oxidized and reduced Nr deposition is needed. Finally, deposition budgets have incomplete information about the speciation of atmospheric nitrogen; monitoring networks do not capture important forms of Nr such as organic nitrogen. Building on these themes, we detail the state of the science of Nr deposition budgets in the U.S. and highlight research priorities to improve deposition budgets in terms of monitoring and flux measurements, leaf- to regional-scale modeling, source apportionment, and characterization of deposition trends and patterns.
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•Deposition budgets for inorganic nitrogen have improved over the last decade in the U.S.•Important data and knowledge gaps in monitoring and modeling of total nitrogen deposition remain.•Expanded monitoring of deposition in agricultural and urban areas is needed.•Monitoring of organic N deposition and improvement of organic N in atmospheric models is needed.•Land use specific modeled deposition estimates are needed for critical load assessments.
Antibodies to several Epstein–Barr virus (EBV)-encoded enzymes are observed in patients with different EBV-associated diseases. The reason for these antibody patterns and the role these proteins ...might play in the pathophysiology of disease, separate from their role in virus replication, is unknown. In this series of studies, we found that purified EBV deoxyuridine triphosphate nucleotidohydrolase (dUTPase) can inhibit the replication of human peripheral blood mononuclear cells in vitro and upregulate the production of TNF-α, IL-1β, IL-6, IL-8, and IL-10. It also enhanced the ability of natural killer cells to lyse target cells. The EBV dUTPase also significantly inhibited the replication of mitogen-stimulated lymphocytes and the synthesis of IFN-γ by cells isolated from lymph nodes and spleens obtained from mice inoculated with the protein. It also produced sickness behaviors known to be induced by some of the cytokines that were studied in the in vitro experiments. These symptoms include an increase in body temperature, a decrease in body mass and in physical activity. The data provide a new perspective on how an early nonstructural EBV-encoded protein can cause immune dysregulation and produce clinical symptoms observed in patients with chronic fatigue syndrome (CFS) separate from its role in virus replication and may serve as a new approach to help identify one of the etiological agents for CFS. The data also provide additional insight into the pathophysiology of EBV infection, inflammation, and cancer.
In vitro studies as well as clinical trials indicate that the cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) enhance the ability ...of neutrophils (polymorphonuclear leukocytes) to eliminate microbial organisms. Toll-like receptor (TLR) proteins, homologs of the Drosophila protein Toll, have been found on the surface of mammalian cells and are important in the responses of macrophages to bacterial, viral, and fungal antigens. TLR4 is critical for the response to lipopolysaccharide (LPS) of gram-negative bacteria, while TLR2 is important for response to gram-positive bacteria, bacterial peptides, and yeast zymosan. We demonstrate that TLR2, but very little TLR4, is present on the surface of human neutrophils. In addition we demonstrate that GM-CSF and G-CSF dramatically up-regulate TLR2 and CD14 surface expression. GM-CSF treatment also up-regulates TLR2 and CD14 mRNA levels in neutrophils. In addition to increasing receptor expression, GM-CSF treatment enhanced the interleukin 8 (IL-8) secretion and superoxide priming responses of neutrophils to stimulation with TLR2 ligands, including zymosan, peptidoglycan, and lipoarabinomannan. The human monocyte response to crude bacterial LPS is composed of a TLR4-specific response to the pure LPS component and a TLR2-dependent response to associated lipopeptides. The removal of TLR2 lipopeptide components from LPS by phenol re-extraction substantially reduced both the IL-8 and superoxide response of the stimulated neutrophils, indicating that, unlike monocytes, the neutrophil response is preferentially directed to TLR2 ligands. Thus, our studies demonstrate that GM-CSF dramatically enhances the functional response of neutrophils to TLR2 ligands, including LPS-associated lipopeptides.
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