Ultrasonographic characteristics of soft tissue tumours in dogs

Objective   To identify and describe the ultrasonographic features of soft tissue tumours in dogs.
Procedure   Superficial soft tissue tumours of various histological types, including mast cell tumours (MCTs) and soft tissue sarcomas (STSs), were evaluated. Ultrasound was used to visualise internal characteristics of the tumour, including vascularity. Tumours were categorised according to size, shape, margin definition, tissue plane mobility, echogenicity, echotexture, acoustic shadowing or enhancement and vessel distribution. Objective measurements of intratumoural blood flow included velocities and maximal perfused cross-sectional area (fractional area). Logistic regression models incorporating a variety of data were used in an attempt to predict the histopathological type of tumours.
Results   The logistic regression model defined by the parameters echotexture, margin definition and presence of subcapsular vessels was highly predictive of MCTs (> 73%; P = 0.024). Several other trends, including a larger size for STSs and less vascularity for both MCTs and STSs, were observed, but did not reach statistical significance.
Conclusion   This preliminary study has shown the potential diagnostic value of ultrasound in differentiating soft tissue tumours. However, at present, ultrasound cannot replace biopsy and histopathological evaluation for tumour diagnosis.     

Associations between Neospora caninum specific antibodies in serum and milk in two dairy herds in Scotland

The study evaluated the use of the Mastazyme ELISA for quantification of Neospora caninum (N. caninum) specific IgG in bovine milk and examined the relationship between serum and milk antibodies in two dairy herds. The serum and milk antibodies both had bimodal distributions in each herd. This was mainly due to between cow variation: in both herds, approximately two thirds of cows were either clearly and consistently seropositive or seronegative for N. caninum with one third consistently near the threshold. Milk and serum N. caninum IgG were strongly related. This relationship was modelled using a linear mixed model including a polynomial term for serum, the effect of herd, and between and within cow variance components. The latter gave a significantly better fit to the data than a model that allowed for a different relationship for the positive and negative (according to the serum test) groups of observations. The sensitivity and specificity (based on serum percentage positivity (pp)) of the milk antibody was determined for different milk pp thresholds. In spite of the differences between the relationship of milk to serum seen for the two herds, for those estimates with sufficient precision, sensitivity and specificity greater than 0.73 for both herds were obtained using single thresholds of 14 and 15.5 for milk pp in both herds based on, as our gold standard, serum antibody pp thresholds of 22.5 and 25, respectively. If milk antibody is to be used for detecting persistently infected cows, the higher threshold of 15.5 may be suitable while for epidemiological screening 14 would be preferable. Further validation in a greater number of herds is required, but our results suggest that this test may prove to be a useful adjunct to serum N. caninum IgG assays in the monitoring of N. caninum infection as part of herd health programmes and epidemiological studies.     

Toward a systems approach to understanding plant cell walls

One of the defining features of plants is a body plan based on the physical properties of cell walls. Structural analyses of the polysaccharide components, combined with high-resolution imaging, have provided the basis for much of the current understanding of cell walls. The application of genetic methods has begun to provide new insights into how walls are made, how they are controlled, and how they function. However, progress in integrating biophysical, developmental, and genetic information into a useful model will require a system-based approach.     

Farmers'' opinions on welfare, health and production practices in extensive hill sheep flocks in Great Britain

Despite large numbers of hill sheep reared in the UK, little is known about how hill farmers react to health challenges in their flocks. This paper addresses this lack of knowledge of sheep health management practices and presents farmers' opinions and concerns, particularly regarding ectoparasite control. Focus groups and interviews with UK hill sheep farmers were carried out to collect information on management practices, health concerns, in addition to incidence and impacts of six major ectoparasites (ticks, lice, sheep scab mite, blowfly, keds and headfly), to determine how they viewed the effects of ectoparasites and their control on production practices.

We conclude that despite variations between hill sheep farm conditions and levels of input, similar health concerns and ectoparasite issues were found across different hill sheep farming areas of the UK. Farm labour was also an important issue and most farmers would prefer more labour to be available to effectively manage ectoparasites in their flocks. Finally, there was variation in farmers' opinions of the impact of ectoparasite species on welfare and productivity. This variation in opinion can be related to a trend in their past experience of ectoparasites, but no relationships were found with the animal health treatments farmers use, the number of animals in their flock or variation in the type of grazing land available.     

Sea-level fingerprinting as a direct test for the source of global meltwater pulse IA

The ice reservoir that served as the source for the meltwater pulse IA remains enigmatic and controversial. We show that each of the melting scenarios that have been proposed for the event produces a distinct variation, or fingerprint, in the global distribution of meltwater. We compare sea-level fingerprints associated with various melting scenarios to existing sea-level records from Barbados and the Sunda Shelf and conclude that the southern Laurentide Ice Sheet could not have been the sole source of the meltwater pulse, whereas a substantial contribution from the Antarctic Ice Sheet is consistent with these records.     

Effects of changing spatial scale on the analysis of landscape pattern

The purpose of this study was to observe the effects of changing the grain (the first level of spatial resolution possible with a given data set) and extent (the total area of the study) of landscape data on observed spatial patterns and to identify some general rules for comparing measures obtained at different scales. Simple random maps, maps with contagion (i.e., clusters of the same land cover type), and actual landscape data from USGS land use (LUDA) data maps were used in the analyses. Landscape patterns were compared using indices measuring diversity (H), dominance (D) and contagion (C). Rare land cover types were lost as grain became coarser. This loss could be predicted analytically for random maps with two land cover types, and it was observed in actual landscapes as grain was increased experimentally. However, the rate of loss was influenced by the spatial pattern. Land cover types that were clumped disappeared slowly or were retained with increasing grain, whereas cover types that were dispersed were lost rapidly. The diversity index decreased linearly with increasing grain size, but dominance and contagion did not show a linear relationship. The indices D and C increased with increasing extent, but H exhibited a variable response. The indices were sensitive to the number (m) of cover types observed in the data set and the fraction of the landscape occupied by each cover type (P _k); both m and P _kvaried with grain and extent. Qualitative and quantitative changes in measurements across spatial scales will differ depending on how scale is defined. Characterizing the relationships between ecological measurements and the grain or extent of the data may make it possible to predict or correct for the loss of information with changes in spatial scale.     

Cobalt deficiency in sheep and diagnostic reference ranges

Abstract

Extract

In the last 2 years, two papers have been published suggesting that current New Zealand reference criteria for diagnosing cobalt deficiency should be reviewed (Grace et al 2003), and they are conservatively high and lead to the over-diagnosis of vitamin B₁₂ deficiency and ill-thriftiness in sheep (Gruner et al 2004). The comments refer to reference ranges cited by animal health diagnostic laboratories. These reference ranges were derived from the paper by Clark et al (1989 Clark, RG, Wright, DF, Millar, KR and Rowland, JD. 1989. Reference curves to diagnose cobalt deficiency in sheep using liver and serum vitamin B₁₂ levels.. New Zealand Veterinary Journal, 37: 7–11. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), which reviewed data from published and unpublished weight gain response trials preceding that date. The review included all published trials in New Zealand and as many unpublished trials that the authors could obtain. They involved serum vitamin B12 data from 54 trials and liver vitamin B₁₂ data from 21 trials. It was stated that more data from trials conducted in autumn were required to reliably determine an autumn response curve. In addition, it was envisaged that as other trial data became available the reference curves could be upgraded (Clark et al 1985 Clark, RG, Wright, DF and Millar, KR. 1985. A proposed new approach and protocol to defining mineral deficiencies using reference curves. Cobalt deficiency in young sheep is used as a model.. New Zealand Veterinary Journal, 33: 1–5. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]).