Increased mean arterial pressure and aldosterone-to-renin ratio in Persian cats with polycystic kidney disease

Polycystic kidney disease (PKD) in Persian cats has been increasingly reported and compared to human autosomal dominant polycystic kidney disease (ADPKD) in the last decade. In cats, however, few studies have dealt with the occurrence and hormonal determinants of hypertension, one of the most common extrarenal manifestations of ADPKD in humans. The purpose of this study was to compare Persian cats >4 years old with PKD to unaffected control cats with regard to blood pressure (BP), plasma renin activity (PRA), serum aldosterone concentration, plasma atrial natriuretic peptide (ANP) concentration, and aldosterone-to-renin ratio (ARR). Three gender- and age-matched groups were studied, each consisting of 7 cats: (1) a control group without cysts, (2) a group with mild PKD, and (3) a group with severe PKD (multiple cysts and renal enlargement). Mild renal insufficiency was found in only 1 of 14 cats with PKD. Cats with PKD had a higher mean arterial pressure (P = .04) and more often had a high ARR (P = .047) than did control cats. Tendencies toward higher diastolic and systolic arterial pressures (DAPs and SAPs, respectively) and lower PRAs were observed in cats with PKD compared to controls (.05 < P < or = .1). No significant differences were found between the groups in serum aldosterone and plasma ANP concentrations. None of the cats had echocardiographic evidence of cardiac hypertrophy. In conclusion, cats with PKD had a minor increase in mean arterial pressure compared to control cats, and half of the cats had a high ARR.     

Analysing land-cover changes in relation to environmental variables in Hesse,Germany

Land-use and land-cover changes affect ecological landscape functions and processes. Hence, landscape ecologists have a central interest in a comprehensive understanding of such changes. Our study focuses on the relationships between environmental conditions and agricultural land-cover changes. We present a method to (i) characterise the major spatial-temporal processes of land-cover changes, (ii) identify the correlations between environmental attributes and land-cover changes and (iii) derive potential environmental drivers of land-cover changes in a German marginal rural landscape. The method was applied to study land-cover dynamics from 1945 to 1998 in the districts of Erda, Steinbrücken and Eibelshausen, situated in the marginal rural landscape of the Lahn-Dill Highlands, Germany. We employed land-cover data gained by the interpretation of multi-temporal aerial photographs. Various environmental variables were introduced into the analyses. We identified physical landscape attributes (elevation, slope, aspect, available water capacity and soil texture) and structural landscape dimensions (patch size, patch shape and distance between patch and nearest settlement). With the aid of GIS, K-means partitioning and canonical correspondence analysis, we investigated land-cover trajectory types, land-cover transitions at individual time intervals and their relationships to these environmental variables. Our results show that, between 1945 and 1998, land-cover changes correlated with the physical attributes of the underlying landscape. On the other hand, the structural landscape dimensions correlated with land cover only in periods of minor land-cover changes (1972–98). Greater diversity of physical landscape attributes is correlated with greater land-cover dynamics. Besides the important influence of socio-economic factors, land-cover changes in the study areas took place within the relatively stable physical constraints of the underlying landscape.This revised version was published online in May 2005 with corrections to the Cover Date.     

Serum-haptoglobin concentration in Danish slaughter pigs of different health status

A cross-sectional study was conducted with 617 finishing pigs aged 10–25 weeks in 11 commercial herds of different health statuses as defined by the Danish monitoring program for specific-pathogen-free (SPF) herds. A standard clinical examination was performed and a blood sample was obtained from each pig for determination of haptoglobin concentration in serum.

Pigs aged 10–14, 15–19 and 20–25 weeks in conventional herds had higher haptoglobin concentrations than high-health SPF (SPF-x) pigs of the same age. There was no significant difference between SPF-x pigs of different ages. Conventional pigs aged 15–19 and 20–25 weeks had higher haptoglobin concentrations than conventional pigs aged 10–14 weeks. Herd influenced the haptoglobin concentration. Lame pigs and pigs with tail or ear bite had elevated haptoglobin concentrations. No significant effect of respiratory symptoms or umbilical hernia was found.     

High prevalence of treponemes in bovine digital dermatitis-a molecular epidemiology

To validate the epidemiology of Treponema spp. associated with digital dermatitis (DD) a large number of DD samples (n=56) were examined by DNA-DNA dot blot analyses using oligonucleotide probes specific for phylogenetic group I-VII of oral treponemes and DD-associated phylotypes DDKL-4, DDKL-12 and DDKL-20 as well as for T. brennaborense and T. socranskii. Positive hybridisation results were obtained for phylogenetic groups I, II and IV and phylotypes DDKL-4 and DDKL-12. While phylotype DDKL-4 was detected in 100% of the samples treponemes belonging to phylogenetic group TRE I, TRE II and TRE IV were prevalent in nearly 80% of the samples and phylotype DDKL-12 was detected in 66.1% of the samples. Analysis of Treponema groups present concurrently in the same sample revealed that a combination of TRE I-TRE II-TRE IV-DDKL-4 was most prevalent and could be detected in up to 71% of the samples. These data indicate that this combination of different Treponema spp. seems to be the most important one in the pathogenesis of DD. In contrast, T. brennaborense originally isolated from DD material this treponeme was not detected in any of the samples clearly indicating that this species is not absolutely associated with DD and therefore may represent only an incidental treponeme. Fluorescence in situ hybridisation (FISH) obviously highlights the invasive character of DD-associated treponemes. Mainly treponemes belonging to phylogenetic group TRE I and phylotype DDKL-4 were detected in high numbers compared to the total number of bacteria and also in deeper layers of the epithelium at the transition of unaffected and affected tissue. Our results confirm a high prevalence and diversity of Treponema spp. in DD lesions. In addition, our data indicate that certain combinations of Treponema spp. are detected much more frequently than others. Furthermore, Treponema spp. appears at the interface between healthy and diseased tissue underlining their importance for the pathogenesis of DD.     

Topography of the casein micelle surface by surface plasmon resonance (SPR) using a selection of specific monoclonal antibodies

Several theoretical models of the casein micelle structure have been proposed in the past, but the exact organization of the four individual caseins (α(s1), α(s2), β, and κ) within this supramolecular structure remains unknown. The present study aims at determining the topography of the casein micelle surface by following the interaction between 44 monoclonal antibodies specific for different epitopes of α(s1)-, α(s2)-, β-, and κ-casein and the casein micelle in real time and no labeling using a surface plasmon resonance (SPR)-based biosensor. Although the four individual caseins were found to be accessible for antibody binding, data confirmed that the C-terminal extremity of κ-casein was highly accessible and located at the periphery of the structure. When casein micelles were submitted to proteolysis, the C-terminal extremity of κ-casein was rapidly hydrolyzed. Disintegration of the micellar structure resulted in an increased access for antibodies to hydrophobic areas of α(s1)- and α(s2)-casein.     

Response of soil microflora to changes in nematode abundance — evidence for large scale effects in grassland soil+

The effect of increasing nematode abundance on microbial biomass and activity in a temperate grassland soil was investigated in a microcosm experiment. The experiment lasted for 33 days. The natural nematode diversity, as well as relevant aspects of the spatial heterogeneity of the soil microhabitat in a 80 m² sampling area were maintained in the microcosms. No correlation was found between nematode abundance and microbial biomass (CFE) or ergosterol content (as a measure of active fungal biomass). However, a doubling of nematode abundance reduced CO₂ production by 11 % and increased bacterial substrate utilization (BIOLOG) by 18 %. A possible explanation is that fungal activity was strongly reduced at higher nematode density, overcompensating the simultaneous increase in bacterial activity. The results show that the nematode community in a grassland soil is capable of causing a considerable shift in soil microbial activities towards an increased bacterial metabolism, overriding the spatial heterogeneity of the soil habitat and the taxonomic diversity of the community itself, and thereby producing functional effects relevant at spatial scales that far exceed the activity domains of the organisms involved.     

Development to Term of Fused and Partially Enucleated Mouse Two-Cell Embryos

Contents: After the blastomeres of mouse two-cell embryos were fused by electric pulses within the zona pellucida, one nucleus of the fusion products was removed following the enucleation method described by McGrath and Solter (1983a, 1983b). 38% (196/520) of the fused embryos were enucleated successfully when Whitten's medium was used as enucleation medium and 434 of 1007 (43%) of the embryos when M 2 was used. 30% (47/159) of the partially enucleated embryos cleaved during their in vitro cultivation but only 3% developed to the morula or blasto cyst stage. 20 young (17%) were born after the transfer of 120 fused and partially enucleated two-cell embryos to 8 pseudopregnant recipients. It was shown that fused and partially enucleated two-cell embryos are able to survive and are able to reach adulthood, although their developmental rate is significantly lower than that of control embryos .
Here we report experiments for the examination of the developmental capacity of two-cell mouse embryos partially enucleated after fusion .     

Critically appraising studies reporting assessing diagnostic tests.

Studies that report the sensitivity and specificity of diagnostic tests are susceptible to flaws that can introduce bias and lead to incorrect estimates. This article uses the quality assessment of diagnostic accuracy studies checklist to describe how to appraise a study reporting diagnostic test comparisons critically. The article also contains a glossary of terms that are useful in discussions about diagnostic tests.     

Parasite population dynamics in pigs infected with Trichuris suis and Oesophagostomum dentatum

The aim of the present study was to investigate the population dynamics and potential interactions between Trichuris suis and Oesophagostomum dentatum in experimentally co-infected pigs, by quantification of parasite parameters such as egg excretion, worm recovery and worm location. Forty-eight helminth naïve pigs were allocated into four groups. Group O was inoculated with 20 O. dentatum L₃/kg/day and Group T with 10 T. suis eggs/kg/day. Group OT was inoculated with both 20 O. dentatum L₃/kg/day and 10 T. suis eggs/kg/day, while Group C was kept as an uninfected control group. All inoculations were trickle infections administered twice weekly and were continued until slaughter. Faecal samples were collected from the rectum of all pigs at day 0, and twice weekly from 2 to 9 weeks post first infection (wpi). Six pigs from each group were necropsied 5 wpi and the remaining 6 pigs from each group were necropsied 10 wpi. The faecal egg counts (FEC) and total worm burdens of O. dentatum were dramatically influenced by the presence of T. suis, with significantly lower mean FECs and worm burdens at 5 and 10 wpi compared to single infected pigs. Furthermore, in the presence of T. suis we found that O. dentatum was located more posteriorly in the gut. The changes in the Trichuris population were less prominent, but faecal egg counts, worm counts 5 wpi (57% recovered vs. 39%) and the proportion of infected animals at 10 wpi were higher in Group OT compared to Group T. The location of T. suis was unaffected by the presence of O. dentatum. These results indicate an antagonistic interaction between T. suis and O. dentatum which is dominated by T. suis.