Dose-response-models and their implications for quantitative risk assessment for Campylobacter infections     

Stellbrink E  Dahms S 《Berliner und Münchener tier?rztliche Wochenschrift》2004,117(5-6):207-213

For some time now there have been several projects dealing with the assessment of campylobacteriosis risks for consumers. Dose-response relationships form a crucial part of such assessments, as they specify disease probabilities depending on different microbial concentrations in foods. Evaluation of such models, however, is difficult because of problems to find data on which reliable assumptions could be based. Ongoing risk analyses for Campylobacter mainly refer to a single administration study with human volunteers published by Black et al. (1988). However, whether results from this study can be transferred to target populations envisaged in risk assessments remains questionable for several reasons. In this paper some alternative dose-response models, their fit to the data of Black et al., and risk estimates resulting in a fictitious scenario are discussed and compared. Depending on the dose-response model assumed risk estimates can differ remarkably. Therefore it is hardly possible to make reliable quantifications of risks in reality, however, it can be determined how much they may vary assuming different scenarios.  相似文献   

The role of aquaporin 4 in the brain     

Iacovetta C  Rudloff E  Kirby R 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2012,41(1):32-44

Emerging evidence suggests that aquaporin (AQP) 4 water channels play an important role in water homeostasis in the brain. These water channels are most abundant in the cell membrane of astrocytes, but are also present within ependymal cell membranes and in osmosensory areas of the hypothalamus. Water transport through AQP4 depends on concentration gradients across the membrane, but the rate of transport is determined by the capacity of astrocytes to up- and down-regulate AQP4 numbers, their location within the membrane, and the overall permeability of the channel. Other functions of brain AQP4 involve potassium uptake and release by astrocytes, migration of glial cells, glial scarring, and astrocyte-to-astrocyte cell communication. AQP water channels are involved in formation and control of edema in the brain and in multiple disease processes in the brain, such as seizures and tumors. There is abundant scientific literature on AQP4 describing its structure, function, location, and role in water homeostasis and edema in the brain. Investigation of AQP expression in the canine and feline brain should be pursued so that clinically relevant comparisons between findings in mice, rats, and people and animal patients can be made.  相似文献   

Comparing silvopastoral systems and prospects in eight regions of the world   总被引：1，自引：1，他引：0  

Frederick Cubbage  Gustavo Balmelli  Adriana Bussoni  Elke Noellemeyer  Anibal N. Pachas  Hugo Fassola  Luis Colcombet  Belén Rossner  Gregory Frey  Francis Dube  Marcio Lopes de Silva  Hayley Stevenson  James Hamilton  William Hubbard 《Agroforestry Systems》2012,86(3):303-314

Silvopasture systems combine trees, forage, and livestock in a variety of different species and management regimes, depending on the biophysical, economic, cultural, and market factors in a region. We describe and compare actual farm practices and current research trials of silvopastoral systems in eight regions within seven countries of the world: Misiones and Corrientes provinces, Argentina; La Pampa province, Argentina; northwestern Minas Gerais, Brazil; the Aysén region of Patagonia, Chile; the North Island of New Zealand; the Southeast United States; Paraguay; and Uruguay. Some countries use native trees and existing forests; some use plantations, particularly of exotic species. Natural forest silvopasture systems generally add livestock in extensive systems, to capture the benefits of shade, forage, and income diversification without much added inputs. Plantation forest systems are more purposive and intensive, with more focus on joint production and profits, for small owners, large ranches, and timber companies. Trends suggest that more active management of both natural and planted silvopastoral systems will be required to enhance joint production of timber and livestock, achieve income diversification and reduce financial risk, make more profit, improve environmental benefits, and realize more resilience to adapt to climate change.  相似文献   

Immunoproteomic analyses of outer membrane antigens of Actinobacillus pleuropneumoniae grown under iron-restricted conditions     

Chung JW  Küster-Schöck E  Gibbs BF  Jacques M  Coulton JW 《Veterinary microbiology》2012,159(1-2):187-194

Actinobacillus pleuropneumoniae, a bacterial pathogen of swine and agent of porcine pneumonia, causes a highly infectious disease of economic importance in the pig industry. Commercial vaccines for A. pleuropneumoniae include whole-cell bacterins and second generation subunit vaccines but they only confer partial protective immunity. Our search for new vaccine candidates identified antigens that are expressed during conditions that mimic infection; the outer membrane (OM) proteome of A. pleuropneumoniae serotype 5b was examined under iron restriction. Quantitative profiling by 2D-DiGE technology revealed that iron restriction induced expression of previously described transferrin binding proteins (TbpA, TbpB) plus four lipoproteins including spermidine/putrescine binding periplasmic protein 1 precursor (PotD2). Immunoproteomic analyses with antisera from na?ve animals and from infected pigs were able to differentiate antigens within the OM proteome that were specifically recognized during A. pleuropneumoniae infection. Immunoblots of iron-restricted profiles detected PotD2, heme-binding protein A (HbpA), and capsule polysaccharide export protein (CpxD) as well as surface antigens TbpA, TbpB, and OmlA. These data identify OM proteins that demonstrate immunogenicity and upregulation under conditions mimicking infection, providing emphasis on lipoproteins as an important class of antigens to exploit for vaccine development for A. pleuropneumoniae.  相似文献   

Comparative evaluation of live marker vaccine candidates "CP7_E2alf" and "flc11" along with C-strain "Riems" after oral vaccination     

Blome S  Aebischer A  Lange E  Hofmann M  Leifer I  Loeffen W  Koenen F  Beer M 《Veterinary microbiology》2012,158(1-2):42-59

Due to the tremendous socio-economic impact of classical swine fever (CSF) outbreaks, emergency vaccination scenarios are continuously under discussion. Unfortunately, all currently available vaccines show restrictions either in terms of marker capacities or immunogenicity. Recent research efforts were therefore directed at the design of new modified live marker vaccines. Among the most promising candidates the chimeric pestiviruses "CP7_E2alf" and "flc11" were identified. Within an international research project, these candidates were comparatively tested in challenge experiments after a single oral vaccination. Challenge infection was carried out with highly virulent CSF virus strain "Koslov", 14 or 21 days post vaccination (dpv), respectively. Safety, efficacy, and marker potential were addressed. All assessments were done in comparison with the conventional "gold standard" C-strain "Riems" vaccine. In addition to the challenge trials, multiple vaccinations with both candidates were performed to further assess their marker vaccine potential. All vaccines were safe and yielded full protection upon challenge 21 days post vaccination. Neither serological nor virological investigations showed major differences among the three vaccines. Whereas CP7_E2alf also provided clinical protection upon challenge at 14 days post vaccination, only 50% of animals vaccinated with flc11, and 83% vaccinated with C-strain "Riems" survived challenge at this time point. No marked differences were seen in protected animals. Despite the fact that all multiple-vaccinated animals stayed sero-negative in the accompanying marker test, the discriminatory assay remains a weak point due to delayed or inexistent detection of some of the vaccinated and subsequently infected animals. Nevertheless, the potential as live marker vaccines could be confirmed for both vaccine candidates. Future efforts will therefore be directed at the licensing of "Cp7_E2alf" as the first live marker vaccine for CSF.  相似文献   

Pharmacokinetics of dexamethasone after intravenous and intramuscular administration in broiler chickens     

Anneleen Watteyn  Heidi Wyns  Elke Plessers  Elisa Russo  Siegrid De Baere  Patrick De Backer  Siska Croubels 《Veterinary journal (London, England : 1997)》2013,195(2):216-220

The aim of this study was to determine the pharmacokinetics of dexamethasone in broiler chickens. Dexamethasone sodium phosphate (0.3 mg/kg bodyweight) was injected IV or IM and blood samples were collected at 0, 0.25, 0.5, 0.75, 1, 2, 4, 6, 8, 10, 12 and 24 h after administration. Dexamethasone in the plasma samples was measured using a liquid chromatography–tandem mass spectrometry method and the pharmacokinetics analysed according to a one-compartmental model.The maximum plasma concentration after IM administration occurred at 0.37 h. The elimination half-life for dexamethasone was 0.46 h and 0.70 h following IV and IM administration, respectively, which was shorter than other species, while the clearance (1.26 L/h kg) was higher than has been reported for other species (<0.5 L/h kg). The volume of distribution (～1 L/kg) was similar to values reported for other species and the bioavailability of dexamethasone after IM administration was 100%. The results from this study will be useful in investigating whether inflammatory disease may affect the pharmacokinetic parameters of dexamethasone in chickens.  相似文献   

Statistical comparison of a new rheological method for defining changes in mash consistency during mashing with the established Rapid Visco Analyser     

Birgit Schnitzenbaumer  Elke K. ArendtJean Titze 《Journal of Cereal Science》2013

The determination of mash consistency proved to be difficult but is of great importance particularly with regard to process and quality control. Therefore, the aim of this study was to develop a new rheological method for precisely determining changes in mash consistency occurring during the mashing process. For that purpose, five mashes with various levels of unmalted oats (0–40%) have been analyzed using a Physica MCR rheometer equipped with a paddle-shaped rotor enabling mash particles to be kept in suspension throughout the rheological measurement. For validating this new method, a statistical comparison with the established Rapid Visco Analyser (RVA) has been carried out. For this purpose, the mash consistency curves have been described by regression functions with the aim to determine characteristic curve points mathematically correct. As a result, the start and end point of starch gelatinization/liquefaction have been well-defined. By calculating the coefficients of determination, good to very good linear correlations between respective curve values and adjunct levels have been found for both methods (MCR and RVA). By calculating the repeatability, however, it has been revealed that the precision of the MCR method is significantly better than that of the RVA method.  相似文献   

<Emphasis Type="Italic">Achromobacter insolitus</Emphasis> and <Emphasis Type="Italic">Zoogloea ramigera</Emphasis> associated with wheat plants (<Emphasis Type="Italic">Triticum aestivum</Emphasis>)     

Valéria Marino Rodrigues Sala  Elke Jurandy Bran Nogueira Cardoso  Fabiana Fantinatti Garboggini  Neusa de Lima Nogueira  Adriana Parada Dias da Silveira 《Biology and Fertility of Soils》2008,44(8):1107-1112

This study reports for the first time the presence of diazotrophic bacteria belonging to the genera Achromobacter and Zoogloea associated with wheat plants. These bacterial strains were identified by the analysis of 16S rDNA sequences. The bacterium IAC-AT-8 was identified as Azospirillum brasiliense, whereas isolates IAC-HT-11 and IAC-HT-12 were identified as Achromobacter insolitus and Zoogloea ramigera, respectively. A greenhouse experiment involving a non-sterilized soil was carried out with the aim to study the endophytic feature of these strains. After 40 days from inoculation, all the strains were in the inner of roots, but they were not detected in soil. In order to assess the location inside wheat plants, an experiment was conducted under axenic conditions. Fifteen days after inoculation, preparations of inoculated plants were observed by the scanning electron microscope, using the cryofracture technique, and by the transmission electron microscope. It was observed that all isolates were present on the external part of the roots and in the inner part at the elongation region, in cortex cells, but not in the endodermis or in the vascular bundle region. No colonizing bacterial cells were observed in wheat leaves.  相似文献   

Intraocular pressure in the smallest primate aging model: the gray mouse lemur          下载免费PDF全文

Marko Dubicanac  Marine Joly  Julia Strüve  Ingo Nolte  Nadine Mestre‐Francés  Jean‐Michel Verdier  Elke Zimmermann 《Veterinary ophthalmology》2018,21(3):319-327

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Textural Comparisons of Gluten‐Free and Wheat‐Based Doughs,Batters, and Breads     

Michelle M. Moore  Tilman J. Schober  Peter Dockery  Elke K. Arendt 《Cereal Chemistry》2004,81(5):567-575

Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.  相似文献