Classification of Dutch and German avian reoviruses by sequencing the sigma C protein

We have amplified, cloned and sequenced (part of) the open reading frame of the S1 segment encoding the sigma C protein of avian reoviruses isolated from chickens with different disease conditions in Germany and The Netherlands during 1980 up to 2000. These avian reoviruses were analysed phylogenetically and compared with sequences of avian reoviruses in the Genbank database. The avian reoviruses could be grouped in 5 different genotyping clusters and this classification was identical when the sequences were compared of the 5' end, the 3' end or the whole open reading frame of the sigma C protein. Therefore sequencing of either part of the gene encoding the sigma C protein seems to be reliable for classification. We were unable to identify a correlation between sigma C sequences of the avian reoviruses and the disease condition they were isolated from. The sequences found in The Netherlands and in Germany are, like those in Taiwan, more dispersed than the known avian reovirus sigma C sequences in the USA and Australia. We did not establish temporal or geographic differences in the avian reoviruses studied.     

Hypofractionated radiation therapy for the treatment of malignant melanoma and squamous cell carcinoma in dogs and cats

This study describes the experience with hypofractionated radiation therapy of squamous cell carcinoma and melanoma in dogs and cats. A total dose of 32-48 Gray (Gy) was delivered once a week in 8 Gy fractions. 34 animals in which a complete surgical excision was impossible were treated. There was no tumor detectable macroscopically in 14 patients at the beginning of radiation therapy. In 20 animals the median volume of the tumor was 9.9 cm3. The median survival times and the local tumor control of squamous cell carcinoma of the oral and nasal cavities and of the body are comparable to results which were reached with a Monday-Wednesday-Friday scheme. For the treatment of Melanoma the hypofractionated radiation therapy is first choice. There are no significant side effects. Late side effects did not occur. 88% of the owners are satisfied with this kind of treatment and would choose it again.     

Trend analysis of Trichinella in a red fox population from a low endemic area using a validated artificial digestion and sequential sieving technique

Freezing of fox carcasses to minimize professional hazard of infection with Echinococcus multilocularis is recommended in endemic areas, but this could influence the detection of Trichinella larvae in the same host species. A method based on artificial digestion of frozen fox muscle, combined with larva isolation by a sequential sieving method (SSM), was validated using naturally infected foxes from Latvia. The validated SSM was used to detect dead Trichinella muscle larvae (ML) in frozen muscle samples of 369 red foxes from the Netherlands, of which one fox was positive (0.067 larvae per gram). This result was compared with historical Trichinella findings in Dutch red foxes. Molecular analysis using 5S PCR showed that both T. britovi and T. nativa were present in the Latvian foxes, without mixed infections. Of 96 non-frozen T. britovi ML, 94% was successfully sequenced, whereas this was the case for only 8.3% of 72 frozen T. britovi ML. The single Trichinella sp. larva that was recovered from the positive Dutch fox did not yield PCR product, probably due to severe freeze-damage. In conclusion, the SSM presented in this study is a fast and effective method to detect dead Trichinella larvae in frozen meat. We showed that the Trichinella prevalence in Dutch red fox was 0.27% (95% CI 0.065-1.5%), in contrast to 3.9% in the same study area fifteen years ago. Moreover, this study demonstrated that the efficacy of 5S PCR for identification of Trichinella britovi single larvae from frozen meat is not more than 8.3%.     

Influence of cropping on the content,composition and dynamics of organic residue in the soil of the plough layer

Organic residue (OR) forms the undecomposed part of soil organic matter (SOM). The majority of it originates from plant remains, but to a certain extent it may also be derived from manure and from the remains of heterotrophic soil organisms. The OR content and dynamics are influenced by management practices (crop rotation, tillage, manuring). The main objective of this work was to study the effect of cropping on the content, fractional composition (coarse and fine fragments) and annual turnover of nonhumified SOM or OR in arable Podzoluvisol in the conditions of south Estonia and to evaluate the role of OR in the humus status of soil. Using the soil-coring method, the OR content and composition and underground phytomass (UGP) as a source of OR in the plough layer were studied. The soil cores (252) were taken during 1991–1992 from three long-term field trials cropped with wheat, barley, rye, potatoes and short-term clover-grass mixtures. The sample plots selected from field trials were tilled conventionally and fertilized according to normal Estonian soil management practice (with a mean rate of N₈₀P₂₃K₄₀ kg ha^-1 year^-1). The average OR content in arable soil ranged from 1.0 to 1.6 g ash-free dry matter (DM_af) kg^-1 soil. The greatest amount of UGP (2.85 g DM_af kg^-1), as a source of OR in soil, was estimated for the 2-year clovergrass mixture. Soil organic carbon accumulated in the composition of OR forms 5.7% of the total organic carbon pool of the plough layer. In regular cropping systems the OR content and pool seem to fluctuate within limits determined by the pedoecological conditions of the soil.     

Dynamic plant uptake model applied for drip irrigation of an insecticide to pepper fruit plants

BACKGROUND: Drip application of insecticides is an effective way to deliver the chemical to the plant that avoids off‐site movement via spray drift and minimizes applicator exposure. The aim of this paper is to present a cascade model for the uptake of pesticide into plants following drip irrigation, its application for a soil‐applied insecticide and a sensitivity analysis of the model parameters. RESULTS: The model predicted the measured increase and decline of residues following two soil applications of an insecticide to peppers, with an absolute error between model and measurement ranging from 0.002 to 0.034 mg kg fw^?1. Maximum measured concentrations in pepper fruit were approximately 0.22 mg kg fw^?1. Temperature was the most sensitive component for predicting the peak and final concentration in pepper fruit, through its influence on soil and plant degradation rates. CONCLUSION: Repeated simulations of pulse inputs with the cascade model adequately describe soil pesticide applications to an actual cropped system and reasonably mimic it. The model has the potential to be used for the optimization of practical features, such as application rates and waiting times between applications and before harvest, through the integrated accounting of soil, plant and environmental influences. Copyright © 2011 Society of Chemical Industry     

Liming and reacidification reactions of a forest lake ecosystem,lake Lysevatten,in SW Sweden

Long-term monitoring, 1973 to 1987, of reactions to liming and reacidification of a forest lake ecosystem near the Swedish west coast is reported in this study. Treatment of Lake Lysevatten with a slag product of limestone in 1974 resulted in neutralization and a positive alkalinity. Prolonged dissolution proceeded for about 7 yr whereby 86% dissolved. During 1984–86 Lake Lysevatten approached maximum reacidification with high Al concentrations and an affected biota. Asellus aquaticus L. decreased and dominance within chironomid groups approached preliming conditions. However, the most obvious biological change was the development of the filamentous algal genus Mougeotia and increased growth of Sphagnum. Populations of both plants increased notably when pH declined to about 5. Our study suggests that extensive reacidification (pH < 6.0) of limed lakes should be avoided by successive treatments to prevent development of destabilized lake ecosystems.     

Genotyping of Mycoplasma gallisepticum and M. synoviae by Amplified Fragment Length Polymorphism (AFLP) analysis and digitalized Random Amplified Polymorphic DNA (RAPD) analysis

Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the cause of considerable economic losses in the poultry industry. Molecular differentiation of avian Mycoplasma strains may be helpful in tracing infections and in the evaluation of implemented intervention strategies. Amplified Fragment Length Polymorphism (AFLP) has shown to be a powerful typing technique but the application for poultry Mycoplasma strains is very limited. The aim of this study was to evaluate the reproducibility and discriminatory power of AFLP HindIII/HhaI and AFLP BglII/Mfel for the inter- and intraspecies differentiation of avian mycoplasmas and to compare these test characteristics with digitalized Random Amplified Polymorphic DNA (RAPD) analysis. The reproducibility of RAPD, AFLP HindIII/HhaI and AFLP BglII/Mfel was 50-100, 97-98 and 86-99%, respectively. RAPD and both AFLP enzyme combinations were able to differentiate between five avian Mycoplasma species. For AFLP, five MG and four MS clusters could be identified. The phylogenetic tree for both enzyme combinations was comparable. For RAPD, four MG clusters could be identified. For MS, however, due to the poor reproducibility of the RAPD technique, no clear genogroups could be identified. On basis of the results of this study it can be concluded that AFLP is a powerful technique for the genotyping of avian mycoplasmas and that, although AFLP HindIII/HhaI generated patterns with less fragments, the final results showed homologous results.     

Cauda equina compression syndrome (CECS): retrospective study of surgical treatment with partial dorsal laminectomy in 86 dogs with lumbosacral stenosis

We report our results of partial lumbosacral laminectomy for treatment of canine Cauda equina Compression Syndrome due to a lumbosacral stenosis. Opposite to conventional techniques of dorsal laminectomy, only widening of the Spatium interarcuale is performed. This is achieved by exstirpation of the Lig. flavum and partial dorsal laminectomy of the first sacral segment. The Proc. spinosi and integrity of facet joints are fully maintained by this technique. In 96.5% of 86 dogs treated with this method relief of dorsal pressure and permanent rapid regression of clinical symptoms was achieved. In two cases recurrence of clinical symptoms was observed during follow up and one case showed no improvement at all. In conclusion partial dorsal laminectomy is a minimal invasive technique for treatment of Cauda equina compression syndrome expressed by pain reaction accompanied by minor neurological deficits caused by lumbosacral stenosis. Maintained spinal stability allows short reconvalescence and the unrestricted use of dogs immediately post operation.