Hemangiosarcoma in cats: 53 cases (1992-2002)

OBJECTIVE: To characterize the biological behavior and prognostic factors associated with hemangiosarcoma in cats. DESIGN: Retrospective case series. ANIMALS: 53 cats with hemangiosarcoma. PROCEDURES: Data were retrieved from a state veterinary diagnostic laboratory, 3 veterinary colleges, and a private practice. RESULTS: Cutaneous and subcutaneous tumor locations were more common than visceral (abdominal and thoracic) and oral locations. Surgical excision was the primary treatment in 47 cats. Tumor-free surgical margins were more likely in cutaneous than subcutaneous lesions and were associated with longer survival times. Local recurrence was observed in 6 of 12 cats with subcutaneous lesions for which follow-up was available. Metastatic disease was detected in 5 of 13 cats with adequate staging at initial diagnosis. A sixth cat had pulmonary metastases at the time of euthanasia. In 4 of 10 cats with visceral hemangiosarcoma, the diagnosis was made at necropsy or they were euthanized at the time of diagnosis. Adjuvant therapy was uncommonly used. Eighteen of the 21 known deaths or euthanasias were tumor-related. Higher mitotic counts (> 3 in 10 hpfs) were associated with shorter survival times. CONCLUSIONS AND CLINICAL RELEVANCE: Subcutaneous hemangiosarcoma was more biologically aggressive than the cutaneous form and was more likely to recur locally and result in euthanasia or death of the cat. Metastatic potential of the cutaneous and subcutaneous forms may be greater than previously reported. Visceral hemangiosarcoma is associated with a grave prognosis.     

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.     

Phosphorus Dynamics in a Luvic Phaeozem After 50 Years of Different P Fertilization

After 50 years of differentiated P fertilization great differences in plant-available P contents between the treatments were measured. However, yield and P uptake varied marginally and only in few plant species these parameters changed significantly. Investigations of P availability, P release and P sorption in different soil depths should show, which phosphorus fractions are important for P supply of agricultural plants in a Luvic Phaeozem. This information can be used for the improvement of fertilization recommendations. A significant decrease in DL-soluble P content in P0 and P15 treatments down to a soil depth of 60cm was measured. Diffusible P content was substantially higher in the P45 treatment in comparison to P0 and P15. Subsoil seems to be an important additional P source. Plant species have a significant influence on phosphorus dynamic. High P sorption in the investigated Luvic Phaeozem, which could not be reduced by excessive P fertilization, may be one of the reasons for low fertilization efficiency in this trial.     

Evaluation of effects of transgenic Bt maize on microarthropods in a European multi-site experiment

The effects of maize expressing the Bacillus thuringiensis Cry1Ab protein (Bt maize) on soil microarthropods were assessed in the field at four European locations (two in Denmark and two in France) that differ in their climatic conditions or soil properties. Each site was considered as a separate experiment, with separate statistical comparison. Effects of farming practices using Bt maize were compared with conventional farming practices using near-isogenic non-Bt maize and also (at some of the sites) other conventional varieties. Furthermore, at one field site (Foulum, Denmark), the effects of Bt crops were studied in both conventional tillage and reduced tillage contexts. At another field site (Askov, Denmark), Bt maize effects were also compared to the effects of the chemical insecticide dimethoate. Moreover, at three of the field sites (all except Narbons, France), the possibility of a localised Bt effect around the rhizosphere compared to the bulk soil was assessed by sampling within and between maize rows. There were some significant negative effects of Bt maize on microarthropods in soils with a high clay content. Significant differences of the same magnitude also occurred between different conventional varieties of maize, but the effect of dimethoate appeared clearly greater than Bt effects. It is thus debatable if the Bt maize effect is an effect of the Bt toxin or just an effect of the maize variety. Based on the results, it can be concluded that the effect of Bt maize on soil microarthropods was small and within the normal variation expected in conventional agricultural systems.     

Soil evaporation under different types of land use in southern African savanna ecosystems

For dryland ecosystems, soil evaporation is a major factor of the soil water balance. Often handled in one term with transpiration, little is known quantitatively about evaporation and impacts of soil and vegetation on it. On 12 plots at three sites in Angola, Namibia, and Botswana, potential and actual evaporation was measured using microlysimeters and parameterized. Dependencies on micrometeorological, soil, and site properties were statistically examined. In simulation runs with SWAP, the microlysimeter measurements were tried to be reproduced. Measured potential evaporation rates varied from 3.0 mm d^–1 to 8.6 mm d^–1. The evaporational parameter β ranged between 0.9 mm^1/2 and 4.3 mm^1/2. Evaporation was found to be strongly impacted by vegetation and land use, increasing from homogeneous bush areas over heterogeneous, more open woodlands to sparsely covered dryland agricultures. Correlations of evaporation variables with temperature, humidity, shading, topsoil water content, pF, bulk density, texture, and C content were found. Relationships were non‐explicit, which could be achieved by combining different factors. The simulation showed satisfying results with small deviations, confirming the model's general ability to depict the process. The application of the Boesten‐Stroosnijder‐model in combination with the used methods showed to be very useful to express evaporational properties, yet further research is necessary to improve consistency. A basis for evaporation prediction from known plot and soil characteristics and temporal and spatial up‐scaling could be given.     

Mojave desert tortoise (Gopherus agassizii) thermal ecology and reproductive success along a rainfall cline

Desert resource environments (e.g. microclimates, food) are tied to limited, highly localized rainfall regimes which generate microgeographic variation in the life histories of inhabitants. Typically, enhanced growth rates, reproduction and survivorship are observed in response to increased resource availability in a variety of desert plants and short‐lived animals. We examined the thermal ecology and reproduction of US federally threatened Mojave desert tortoises (Gopherus agassizii), long‐lived and large‐bodied ectotherms, at opposite ends of a 250‐m elevation‐related rainfall cline within Ivanpah Valley in the eastern Mojave Desert, California, USA. Biophysical operative environments in both the upper‐elevation, “Cima,” and the lower‐elevation, “Pumphouse,” plots corresponded with daily and seasonal patterns of incident solar radiation. Cima received 22% more rainfall and contained greater perennial vegetative cover, which conferred 5°C‐cooler daytime shaded temperatures. In a monitored average rainfall year, Cima tortoises had longer potential activity periods by up to several hours and greater ephemeral forage. Enhanced resource availability in Cima was associated with larger‐bodied females producing larger eggs, while still producing the same number of eggs as Pumphouse females. However, reproductive success was lower in Cima because 90% of eggs were depredated versus 11% in Pumphouse, indicating that predatory interactions produced counter‐gradient variation in reproductive success across the rainfall cline. Land‐use impacts on deserts (e.g. solar energy generation) are increasing rapidly, and conservation strategies designed to protect and recover threatened desert inhabitants, such as desert tortoises, should incorporate these strong ecosystem‐level responses to regional resource variation in assessments of habitat for prospective development and mitigation efforts.     

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.