Predicting Recovery from Acidic Deposition: Applying a Modified TAF (Tracking and Analysis Framework) Model to Maine (USA) High Elevation Lakes

We adapted a reduced-form model, built to predict the aquatic effects of alternative nitrogen and sulfur emissions scenarios on Adirondack lakes, New York, for use on high elevation lakes of Maine (HELM), USA. The Tracking and Analysis Framework (TAF) model was originally designed to evaluate the biotic, economic, and health effects of acid deposition. The TAF model developed in our study was used to assess the biotic effects of different levels of sulfate deposition resulting from alternative emissions scenarios. The aquatic portion of the model is based on a lumped-parameter watershed chemistry model, MAGIC (Model of Acidification of Groundwater in Catchments). The original TAF model was built by calibrating MAGIC to 33 lakes in the Adirondack Mountains. We calibrated MAGIC to 78 HELM lakes, and built reduced-form models from these MAGIC predictions. We evaluated TAF predictions of acid neutralizing capacity (ANC), a fish acid stress index (ASI), and the probability of fish presence in 2030 for four different SO₂ emissions-reduction scenarios. The most dramatic emissions reduction scenario produced only modest increases in mean ANC (16.8 μeq/L ± 7.9 μeq/L) and slight increases in mean predicted probability of presence of acid-sensitive fish (0.07± 0.09) across all lakes. However, a small number of lakes were predicted to have more substantial increases in ANC and improvements in other conditions for acid-sensitive fish. Our results reflect the reality that many of the high elevation lakes of Maine historically had low ANC and that some were even acidic in pre-industrial times. Thus, ’recovery’ for most of the high elevation lakes of Maine will be modest under any scenario of reduced acidic deposition.     

Litterfall Mercury in Two Forested Watersheds at Acadia National Park, Maine, USA

Litterfall can be an important flux of mercury (Hg) to soils in forested landscapes, yet typically the only available data to evaluate Hg deposition is from precipitation Hg monitoring. Litterfall was collected at 39 sampling sites in two small research watersheds, in 2003 and 2004, and analyzed for total Hg. Four vegetation classes were designated in this study as hardwoods, softwoods, mixed and scrub. The mean litter Hg concentration in softwoods (58.8 ± 3.3 ng Hg g^?1 was significantly greater than in mixed (41.7 ± 2.8 ng Hg g^?1 and scrub (40.6 ± 2.7 ng Hg g^?1, and significantly lower than in hardwoods (31.6 ± 2.6 ng Hg g^?1. In contrast, the mean weighted litter Hg flux was not significantly different among vegetation classes. The lack of a significant difference in litter Hg flux between hardwoods and softwoods was attributable to the large autumnal hardwood litter Hg flux being balanced by the higher softwood litter Hg concentrations, along with the higher chronic litterfall flux throughout the winter and spring in softwoods. The estimated annual deposition of Hg via litterfall in Hadlock Brook watershed (10.1 μg m^?2 and Cadillac Brook watershed (10.0 μg m^?2 was greater than precipitation Hg deposition and similar to or greater than the magnitude of Hg deposition via throughfall. These results demonstrate that litterfall Hg flux to forested landscapes can be at least as important as precipitation Hg inputs.     

Influence of toltrazuril treatment on parasitological parameters and health performance of piglets in the field--an Austrian experience

Porcine coccidiosis caused by Isospora suis is one of the leading causes of neonatal diarrhea in suckling piglets. Currently the only registered drug for metaphylaxis is toltrazuril. To evaluate the effect of treatment on piglets from 7 Austrian farms without and 8 Austrian farms with toltrazuril application we examined oocyst excretion (including determination of oocysts per gram of feces; OPG), diarrhea (fecal score FS 1-4 with 3 and 4 being diarrhea), and general health (health score HS 1-4 with 3 and 4 describing poor health). Both groups included farms with different levels of hygiene. Samples from 265 litters without treatment, comprising 1588 individual samples, and 1548 samples from 258 treated litters were taken twice (around the 14th and the 21st day of life, respectively), examined by autofluorescence and, if positive, by McMaster counting. In both groups animals had less diarrhea and lower health scores during the second sampling but the treated piglets were always significantly healthier and had less diarrhea. The percentage of weaned piglets was higher in treated animals although this was not significant (p=0.052). In the first round of sampling 17.8% of the individual samples from untreated piglets were positive for oocysts (with a maximum prevalence on the 12-15th day of life) while in the treated piglets only 0.4% shed oocysts p<0.001). At the second sampling only 2.1% of the untreated animals and none of treated piglets excreted I. suis (p=0.083). Positive animals shed up to 8 × 10(3)OPG. There was an increased risk for infected piglets to develop diarrhea (odds ratio, OR 4.73) and poor health (OR 5.05) in untreated piglets, and poor hygiene without disinfection was identified as a risk factor for poor health (OR 1.90), diarrhea (OR 1.42) and oocyst excretion (OR 1.73). The risk of poor health (OR 2.89) and diarrhea (OR 1.44) was also increased for piglets under poor hygienic conditions receiving toltrazuril, so both metaphylaxis of coccidiosis and good hygiene are necessary to effectively control neonatal diarrhea. The costs of treatment are considerably lower than the estimated financial production losses. Therefore, treatment is recommended for farms where clinical coccidiosis is diagnosed.     

Effect of antecedent soil moisture conditions on emissions and isotopologue distribution of N2O during denitrification

The present study determined the influence of initial moisture conditions on the production and consumption of nitrous oxide (N₂O) during denitrification and on the isotopic fingerprint of soil-emitted N₂O. Sieved arable soil was pre-incubated at two different moisture contents: pre-wet at 75% and pre-dry at 20% water-filled pore space. After wetting to 90% water-filled pore space the soils were amended with glucose (400 kg C ha⁻¹) and KNO₃ (80 kg N ha⁻¹) and incubated for 10 days under a He/O₂-atmosphere. Antecedent moisture conditions affected denitrification. N₂ + N₂O fluxes and the N₂O-to-N₂ ratio were higher in soils which were pre-incubated under dry conditions, probably because mobilization of organic C during the pre-treatment enhanced denitrification. Gaseous N fluxes showed similar time patterns of production and reduction of N₂O in both treatments, where N₂O fluxes were initially increasing and maximised 3-4 days after fertilizer application, and N₂ fluxes were delayed by 1-2 days. Time courses of δ¹⁵N^bulk-N₂O and δ¹⁸O-N₂O exhibited in both treatments increasing trends until maximum N₂ fluxes occurred, reflecting isotope fractionation during intense NO₃⁻ reduction. Later this trend slowed down in the pre-dry treatment, while δ¹⁸O-N₂O was constant and δ¹⁵N^bulk-N₂O decreased in the pre-wet treatment. We explain these time patterns by non-homogenous distribution of NO₃⁻ and denitrification activity, resulting from application of NO₃⁻ and glucose to the surface of the soil. We assume that several process zones were thus created, which affected differently the isotopic signature of N₂O and the N₂O and N₂ fluxes during the different stages of the process. We modelled the δ¹⁵N^bulk-N₂O using process rates and associated fractionation factors for the pre-treated soils, which confirmed our hypothesis. The site preference (SP) initially decreased while N₂O reduction was absent, which we could not explain by the N-flux pattern. During the subsequent increase in N₂ flux, SP and δ¹⁸O-N₂O increased concurrently, confirming that this isotope pattern is indicative for N₂O reduction to N₂. The possible effect of the antecedent moisture conditions of the soil on N₂O emissions was shown to be important.     

Modeling the effects of estradiol and progesterone on the acute phase proinflammatory axis: variability in tumor necrosis factor-α, nitric oxide, and xanthine oxidase responses to endotoxin challenge in steers

The severity of host response in some diseases differs between sexes, and this dimorphism has been attributed to the immunomodulating effects of reproductive steroid hormones. In females, susceptibility to disease stress has been associated with reproductive status and attributed to prevailing progesterone (P4) or estrogen concentrations during different estrous cycle phases. Our objective was to clarify and define the effect of P4 or 17β-estradiol (E2) on the acute proinflammatory component of the innate immune system by administering these hormones to steers and evaluating initial and tolerance-associated concentration patterns of circulating proinflammatory immune response mediators after two consecutive lipopolysaccharide (LPS) challenges (LPS1 and LPS2, 6 d apart; 2.5 μg/kg BW, intravenously, Escherichia coli 055:B5). Plasma concentrations of the proinflammatory initiation cytokine tumor necrosis factor-α (TNF-α), nitrate+nitrite [NO(x), estimate of nitric oxide (NO) production], haptoglobin (HG; acute phase protein) and plasma xanthine oxidase activity (mediator of superoxide production) were measured. Crossbred steers (392 ± 7 kg) were fed a forage-concentrate diet (15% CP) to appetite and assigned to control (C; n = 7), P4 (n = 8), or E2 (n = 5) treatment. Jugular blood samples were obtained at 0, 1, 2, 3, 4, 7, and 24 h relative to each of the two LPS injections. For each proinflammatory biomarker, the area under the time by concentration curve (AUC) was used to evaluate and compare responses to the LPS challenge. Treatment with E2 disrupted LPS tolerance as observed in augmented plasma TNF-α (P < 0.01) and NO(x) (P < 0.01) responses to LPS2. Compared with C, P4 treatment decreased plasma NO(x) AUC after LPS2 (P < 0.05) and tended to reduce TNF-α AUC after LPS1 (P = 0.08). Plasma xanthine oxidase activity AUC was increased (P < 0.01) over C by E2 treatment after both LPS1 and LPS2. HG response to LPS1 within 24 h was not affected by any treatment. However, 6 d after LPS1 plasma HG concentration remained higher (P < 0.01) in steers treated with E2 than with C or P4. Results indicate that in cattle, P4 and E2, respectively, attenuate or amplify the response to LPS challenge at several points critical to the regulation of the progression of the proinflammatory cascade.     

Plasma concentrations of thyroid hormone in steers treated with Synovex-S and 3,5,3'-triiodothyronine.

This experiment examined the effect of daily administration of 3,5,3'-triiodothyronine (T3) on plasma profiles of T3, thyroxine (T4), 3,3',5'-triiodothyronine (reverse T3; rT3) and thyrotropin (TSH) in beef steers in which protein accretion was increased by using implants of Synovex-S (SYN). Twenty-four Angus-Hereford steers (302 +/- 16 kg) were individually fed a diet of a corn-based concentrate and silage mixture for 56 d at equal energy intake per steer (ME/unit BW.75). A 2 x 2 factorial arrangement of treatments was used in which treatments were SYN ear implants (200 mg of progesterone and 20 mg of estradiol benzoate) or no implants and s.c. injections of T3 in polyethylene glycol (2 micrograms of T3/kg BW every 48 h) or no injections of T3. Blood samples were collected every 2 wk. Plasma T3 concentration during the experimental period was increased in T3-treated steers (3.0 +/- .1 vs 2.2 +/- .1 ng/mL, P < .01) and was decreased in SYN-implanted steers (2.4 +/- .1 vs 2.7 +/- .1 ng/mL, P < .01). Plasma T4 and rT3 concentrations were reduced (22 +/- 4 vs 75 +/- 2 and .04 +/- .01 vs .12 +/- .01 ng/mL, respectively, P < .01) in T3-treated steers. Concurrently, plasma TSH concentration was decreased in T3-treated steers (.37 +/- .01 vs .51 +/- .02 ng/mL, P < .02). Synovex-S increased BW gain (21.0%, P < .01) and protein gain (35.6%, P < .01) compared with that of nonimplanted steers. Body weight gain and protein gain were not affected by treatment with T3.(ABSTRACT TRUNCATED AT 250 WORDS)     

The ECVP/ESVP summer school in veterinary pathology: high-standard, structured training for young veterinary pathologists

This article describes the ECVP/ESVP Summer School in Veterinary Pathology, a new annual two-week European training facility established by the European College of Veterinary Pathologists (ECVP) in collaboration with the European Society of Veterinary Pathology (ESVP). The aim of the Summer Schools is to provide Europe-wide, harmonized, top-standard theoretical and practical post-graduate training for veterinarians specializing in veterinary pathology. In particular, it aims to support trainees in veterinary pathology in their individual preparation for the ECVP certifying examination. Ultimately, it aims to provide young pathologists with the skills and knowledge necessary to participate in international, high-quality research and the tools for applying international standards to their own research and for independent study for the ECVP certifying examination, even if they do not work in comparable academic environments and do not have the same level of local support and training. The ECVP/ESVP Summer Schools take place in European countries, with local organization from a university department of veterinary pathology. Each event comprises modules provided by internationally recognized specialists in their specific fields of expertise on different organ systems, diseases of specific species, specific techniques, and specific topics relevant to pathology, forming a cycle of four events to cover all major topics. Every two years a mock exam is organized as a tool to monitor individual progress in preparing for the ECVP certifying examination.     

Modeling growth factor activity during proinflammatory stress: methodological considerations in assessing cytokine modulation of IGF binding proteins released by cultured bovine kidney epithelial cells

The present research was conducted to model potential mechanisms through which IGFBPs might be affected by a key proinflammatory response initiating cytokine tumor necrosis factor (TNF-)-. Madin–Darby bovine kidney epithelial (MDBK) cells, known to release IGFBPs in response to several stimuli, were grown under several conditions and challenged with forskolin (F) or recombinant TNF- for 24 h. Forskolin increased IGFBP-3 gene expression and media content of BP-3 protein. TNF- increased basal and augmented F-mediated IGFBP-3 gene expression. However, TNF- effects on the measurable media content of IGFBPs were influenced by culture conditions; in the absence of added protease inhibitors (PIs) or sufficient media albumin concentration (high BSA, 1 mg/ml), the effect of TNF- was to decrease (P < 0.02) measurable IGFBPs. In the presence of PI and high BSA, media IGFBP-3 levels were shown to be increased by TNF- consistent with the gene expression data. Changes in media IGFBP-3 protease activity were examined further to explain the observed effects of TNF- on production and destruction of IGFBPs in media. When recombinant human IGFBP-3 (500 ng/ml) was added to PI-free, low BSA 100 μg/ml) media from TNF-treated MDBK cells, less than 10% of the BP-3 was recognizable by Western blot in 30 min; conversely, inclusion of High BSA and PI in media resulted in attenuation of the protease effect on the IGFBPs. The data suggest that the MDBK model of cellular response to proinflammatory stimulus is affected by culture conditions and that TNF- affects media content of IGFBPs through effects on IGFBP gene expression coupled with degradation of IGFBPs via enhanced proteolytic enzyme release.     

Analysis of systematic and genetic effects on the prevalence of primary cataract, persistent pupillary membrane and distichiasis in the two color variants of English Cocker Spaniels in Germany

Genetic parameters were estimated for prevalences of primary cataract (CAT), persistent pupillary membrane (PPM) and distichiasis (DIST) in 615 single-colored and 617 multi-colored English Cocker Spaniels (ECS) bred in the German kennel club for Spaniels (Jagdspaniel-Klub e.V.). CAT or CAT diagnosed in dogs up to three and a half years of age (early-onset cataract, CAT-early) and CAT diagnosed in dogs over three and a half years of age (late-onset cataract, CAT-late), PPM and DIST were included as binary traits in multivariate genetic analyses. Heritabilities on the underlying liability scale were 0.15 for CAT, 0.34 for CAT-early, 0.13 for CAT-late, 0.46 for PPM, and 0.62 for DIST in single-colored ECS and 0.06 for CAT, 0.13 for CAT-early, 0.14 for CAT-late, 0.10 for PPM, and 0.61 for DIST in multi-colored ECS. There were indications for a different genetic basis of CAT-early and CAT-late in single-colored ECS as genetic correlations were close to zero. In multi-colored ECS, a similar tendency for CAT-early and CAT-late could be observed.     

The implementation of the broth microdilution method to determine bacterial susceptibility to antimicrobial agents

The determination of quantitative data (minimal inhibitory concentrations [MIC values]) using the broth microdilution method is considered the method of choice for in-vitro susceptibility testing of bacterial pathogens. For the inoculation of microtiter plates used in the broth microdilution method, an inoculation density of 5x10(5) CFU/ml has to be achieved according to the CLSI standard. In this study, it was shown that the requested CFU/ml corresponded to an optical density of 0.00027 of a bacterial suspension determined in a spectrophotometer at 625 nm (OD625).The comparison of susceptibility data of clinical isolates determined by agar disk diffusion and, in parallel, by broth microdilution confirmed the comparability of both methods. For most antibiotics the frequency of "very major errors" was below 10%. However, a higher frequency of errors was observed for combinations of antimicrobial agents and bacteria for which no valid breakpoints are available. The comparative testing of cephalothin showed a frequency of"very major errors" of 20.3% for staphylococci and 18.4% for Enterobacteriaceae; for apramycin the frequency of "major errors"was found to be 46.0% for Enterobacteriaceae. The reference strains as recommended in the CLSI Standard M31-S1 should be used for quality assurance.