Der Einfluß von Dieselkraftstoff auf die Aggregatstabilität,den Plastizitätsindex und das Scherverhalten unterschiedlicher Bodenmaterialien

The effect of Diesel fuel on stability of aggregates, plasticity index and shear strength of two soil materials The influence of Diesel fuel contamination on mechanical properties of soil are investigated with regard to the retreatment of materials after a cleaning process. Following aspects are examined in laboratory tests: waterstability of aggregates, plasticity index and shear strength parameter. The used soil materials are mixed samples of a Luvisol (=Bt) and a tidal influenced alluvial clay sediment of a Gley (=Klei). The aggregate stability of Bt material is rising at increasing Diesel fuel contaminations due to a hydrophob effect on the surfaces of the aggregates. This influence cannot be shown for clay material. On the other hand the plasticity index shows a decrease for low Diesel fuel contaminations, because the Diesel fuel acts directly to the particle surfaces. At increasing contaminations these effects are overlayed by increasing viscosity and shear strength of water and Diesel fuel phases or emulsions. The increase in stability of aggregates is not evident in a shear box test. The Diesel fuel shows no influence to angle of internal friction for both investigated materials. On the other hand there is an effect to the cohesion. This phenomenon could be explicated with above mentioned increase in cohesion due to an increase in shear strength and viscosity of a two phase system.     

The additional costs of segregated transport to slaughter to decrease Salmonella prevalence in pork--a simulation study

A stochastic simulation model was used to assess the additional costs related to segregated transport to slaughter. This control measure was assumed to be implemented within a producers' association to decrease Salmonella prevalence in pork. Calculations were based on the additional shipments caused by the separate transport of low- and high-prevalence herds and on the additional transport distance caused by changed routing. The results showed that there is not necessarily a considerable increase in the number of shipments due to herd status separation for transport. The percentage of shipments changed due to segregated transport varied between 43% and 69% depending on the threshold prevalence. The additional costs per slaughtered pig varied between 0.07€/pig and 0.58€/pig under the given assumptions. Costs were governed by the percentage of changed shipments and the additional distance of a changed shipment. Due to the fact that the percentage of changed shipments is related to the distribution of herd prevalence within the producers' association, there is no cost-effective threshold in general. Different producers' associations incur different costs caused by segregated transport to slaughter at the same threshold prevalence. The current study supports producers' associations in evaluating the additional costs of segregated transport for their members.     

Assessing individual sow risk factors for coliform mastitis: a case-control study

In order to investigate sow-specific risk factors associated with coliform mastitis, a case-control study was performed over the course of 28 months. Data of three farms were collected under production conditions. Sows suffering from coliform mastitis after farrowing served as cases, and healthy half- or full-sib sows from the same farm served as controls. Individual sow characteristics and the seasonal influence were analysed by conditional logistic regression. The final multivariate model identified four risk factors: the risk of suffering from coliform mastitis increased with a higher number of piglets born alive and stillborn piglets. Gilts had an increased risk for the disease, and birth intervention was also associated with a higher prevalence of mastitis. Birth induction and season had no significant influence on the occurrence of coliform mastitis. The time during and soon after farrowing is a very sensitive period in pig production demanding great attention by the farmer. With respect to the economic losses, monitoring of potentially endangered sows as well as detailed documentation and selection of disease cases are of particular importance when coping with coliform mastitis.     

Comparison of virulence gene profiles of Escherichia coli isolates from sows with coliform mastitis and healthy sows

Coliform mastitis (CM) is not only a serious economical and animal welfare touching problem in dairy cattle, but also in sows after farrowing. Due to this disease, the essential adequate supply with colostrum for the growth and the health of the piglets is not ensured. Besides other influencing factors, Escherichia (E.) coli is of great importance as a causative agent of this multifactorial disease. In this study, E. coli isolates from milk samples of healthy and CM-affected sows were examined for the presence of virulence genes associated with extraintestinal E. coli strains, enterotoxigenic E. coli and other pathogenic E. coli. The isolated E. coli harbored mainly virulence genes of extraintestinal E. coli strains (especially fimC, ompA, traT, hra, kpsMTII, iroN). The virulence gene spectrum for both samples from CM-affected and healthy sows did not differ significantly. Particular virulence gene profiles of E. coli isolates from diseased sows were not detected. This study provides novel insights into the role of E. coli in association with mastitis in sows since it is the first time E. coli isolates from CM-affected sows' milk were analysed for virulence genes. Because there were no differences in the prevalence of E. coli and their virulence-associated genes between healthy and diseased sows, other causative factors seem to have greater influence on the pathogenesis of porcine CM.     

Genetic approach for the fast discovery of phenazine producing bacteria

A fast and efficient approach was established to identify bacteria possessing the potential to biosynthesize phenazines, which are of special interest regarding their antimicrobial activities. Sequences of phzE genes, which are part of the phenazine biosynthetic pathway, were used to design one universal primer system and to analyze the ability of bacteria to produce phenazine. Diverse bacteria from different marine habitats and belonging to six major phylogenetic lines were investigated. Bacteria exhibiting phzE gene fragments affiliated to Firmicutes, Alpha- and Gammaproteobacteria, and Actinobacteria. Thus, these are the first primers for amplifying gene fragments from Firmicutes and Alphaproteobacteria. The genetic potential for phenazine production was shown for four type strains belonging to the genera Streptomyces and Pseudomonas as well as for 13 environmental isolates from marine habitats. For the first time, the genetic ability of phenazine biosynthesis was verified by analyzing the metabolite pattern of all PCR-positive strains via HPLC-UV/MS. Phenazine production was demonstrated for the type strains known to produce endophenazines, 2-hydroxy-phenazine, phenazine-1-carboxylic acid, phenazine-1,6-dicarboxylic acid, and chlororaphin as well as for members of marine Actinobacteria. Interestingly, a number of unidentified phenazines possibly represent new phenazine structures.     

Assessment of left atrial appendage flow velocity and its relation to spontaneous echocardiographic contrast in 89 cats with myocardial disease

The hypotheses of this prospective study were that (1) left atrial appendage (LAA) blood flow velocities can be recorded in cats with myocardial disease by transthoracic Doppler echocardiography, (2) LA enlargement, LA mechanical dysfunction, and left ventricular (LV) diastolic abnormalities are associated with decreased LAA flow velocities, and (3) low LAA flow velocities predict the appearance of spontaneous echocardiographic contrast in cats with cardiomyopathy. Transthoracic 2-dimensional, M-mode, and Doppler echocardiographic studies were performed in 89 cats with hypertrophic, restrictive, dilated, or unclassified cardiomyopathy or with hyperthyroid heart disease. Maximal LAA flow velocity (LAAmax) was decreased (P < .001) in cats with cardiomyopathy (median, 0.28 m/s; range, 0.08-1.35) compared to normal cats. Associated with decreased LAA flow velocities were increased LA size, decreased LA function, increased severity of LV diastolic dysfunction, and the presence of congestive heart failure. Multivariate logistic regression analysis detected an LAAmax <0.20 m/s as the only independent variable to predict LA spontaneous echocardiographic contrast (odds ratio, 30.1; 95% confidence interval [CI], 4.1 222.3; P < .001). Receiver operating characteristic analysis performed to predict spontaneous echocardiographic contrast indicated an area under the curve of 0.88 (95% CI, 0.80-0.95; P < .001) with sensitivities of 100 and 74% and specificities of 69 and 83% for LAAmax <0.25 and <0.20 m/s, respectively. Thus, low LAA flow velocities identified a subgroup of patients at increased risk of spontaneous echocardiographic contrast and possible thromboembolism. These findings may have important clinical implications for anticoagulation therapy and prognostication in cats with cardiomyopathy.     

The secretory pattern and source of immunoreactive prolactin in pregnant African (Loxodonta africana) and Asian (Elephas maximus) elephants

The objective of the present study was to define the secretion of prolactin (PRL) in pregnant African and Asian elephants. Levels of immunoreactive (ir-) PRL in serum and placental homogenates were measured by a heterologous radioimmunoassay (RIA) based on an ovine and human RIA system, and the localization of ir-PRL in the placenta was detected by immunohistochemistry using anti-human PRL. Circulating ir-PRL clearly showed a biphasic pattern during pregnancy in African and Asian elephants. Serum levels of ir-PRL started to increase from the 4 - 6th month of gestation and reached the first peak level around the 11-14th month. A second peak of circulating ir-PRL levels was observed around the 18-20th month of gestation followed by an abrupt decline after parturition. In contrast, in a case of abortion of an African elephant, the second peak of ir-PRL was not observed, and the levels remained low for about four months until parturition. The weight of the fetus delivered at the 17th month of gestation was 23.5 kg, which was quite small compared with normal fetuses in previous reports. Ir-PRL was detected in placental homogenates, and immunolocalization was observed in trophoblasts in both the African and Asian elephants, indicating that the placenta is the source of ir-PRL during pregnancy in elephants. The present results clearly demonstrated that circulating ir-PRL shows a biphasic pattern during normal pregnancy and that the placenta appears to be an important source of circulating ir-PRL during pregnancy in both African and Asian elephants.     

An immunohistochemical study of the role of matrix metalloproteinases and their tissue inhibitors in chronic mitral valvular disease (valvular endocardiosis) in dogs

While the pathogenesis of chronic valvular disease (CVD) in dogs remains unclear, alterations in the activity of specific metalloproteinase enzymes and their inhibitors within the valve stroma are suspected of having a role. This study describes the immunohistochemical distribution pattern of matrix metalloproteinase (MMP) types 2, 9 and 14 and their tissue inhibitors, termed tissue inhibitors of metalloproteinase (TIMP), types 2 and 3, in normal canine mitral valves (MVs) (n=10) and in dogs with mild (n=7), moderate (n=14) and severe (n=9) CVD. In normal MVs, MMP-2 and -14, and TIMP-2 were expressed in isolated stromal cells. Tissue inhibitor of metalloproteinase-3 exhibited moderate intracellular and mild extracellular expression. With increasing severity of CVD, the expression of MMP-2 decreased. The number of stromal cells expressing MMP-14 increased, predominantly in the margins of the nodular lesions. Tissue inhibitor of metalloproteinase-2 and -3 expression increased both intra- and extracellularly. Matrix metalloproteinase-9 was not detected in normal or diseased valves. In conclusion, CVD was characterised by alterations in the distribution and intensity of valvular MMP and TIMP expression, suggesting that depressed catabolism and the accumulation of extracellular matrix components within affected valves contributes to their structural alteration and consequent loss of function.