The occurrence of congenital heart defects in an inbred herd of pigs in Australia

OBJECTIVE: To report on the first case of congenital heart defects in pigs in Australia. DESIGN: Retrospective analysis of case records from an inbred herd of "Westran" pigs at the University of Sydney, between January 2001 and December 2004. Detailed gross and histological examination of 15 hearts from pigs that had died or were euthanased in 2004. CASE DETAILS: The necropsy records from a population of 471 pigs that had died (106 pigs) or were euthanased for research purposes (365 pigs) were analysed and the incidence of heart defects recorded, together with basic demographic data. No attempts were made to diagnose the condition in live pigs. RESULTS: Congenital heart defects were diagnosed in 6.4% of pigs but this is likely to be an underestimate of the incidence of the deformity. Eighteen pigs died on the farm as a result of the defect, and 12 pigs were diagnosed with the defect as an incidental finding. The most common abnormality seen at necropsy was a sac-like dilatation on the right lateral surface of the right atrium. This was associated with secondary deformity and hypoplasia of the adjacent left ventricle, interventricular region and part of the right ventricle. All hearts showed atrial septal defects of varying size. CONCLUSION: This is the first reported case of congenital heart defects in pigs in Australia, and one of less than five reported cases of atrial septal defects in pigs in the world. The authors conclude that there may be an element of genetic predisposition to the malformation, since it has only been reported in this inbred line of pigs.     

Iron catalysts for selective anti-Markovnikov alkene hydrosilylation using tertiary silanes

Alkene hydrosilylation, the addition of a silicon hydride (Si-H) across a carbon-carbon double bond, is one of the largest-scale industrial applications of homogeneous catalysis and is used in the commercial production of numerous consumer goods. For decades, precious metals, principally compounds of platinum and rhodium, have been used as catalysts for this reaction class. Despite their widespread application, limitations such as high and volatile catalyst costs and competing side reactions have persisted. Here, we report that well-characterized molecular iron coordination compounds promote the selective anti-Markovnikov addition of sterically hindered, tertiary silanes to alkenes under mild conditions. These Earth-abundant base-metal catalysts, coordinated by optimized bis(imino)pyridine ligands, show promise for industrial application.     

Progress of the comparative MHC Committee and a summary of the Comparative MHC Workshops held at the 32nd ISAG, Edinburgh and the 9th IVIS, Tokyo, 2010

The comparative MHC Nomenclature Committee was formed following a recommendation by the International Society for Animal Genetics (ISAG) at its meeting in G?ttingen, Germany in 2002. The committee subsequently became affiliated to VIC, the Veterinary Immunology Committee of IUIS; the International Union of Immunological Societies, which is the umbrella organization for immunology societies worldwide. The committee currently fulfils three roles: (1) to establish guidelines for MHC nomenclature in species outside of human and mouse, (2) to facilitate the development of databases which provide a source of validated MHC sequences with official nomenclatures for associated species (immuno-polymorphism database IPD-MHC) and (3) to facilitate scientific discussion on comparative aspects of MHC biology. The committee currently comprises individuals representing a range of species nomenclature committees. This report summarises progress the committee has made in addressing its core objectives as well as the principal outputs from the Comparative MHC Workshops held at the 32nd International Society for Animal Genetics (ISAG) conference in Edinburgh, UK in July 2010 as well as in August 2010 at the 9th International Veterinary Immunology Symposium (IVIS) in Tokyo, Japan. Additional data from posters and presentations at related workshops focussing on aspects of MHC biology are also included where appropriate.     

Risk factors associated with extended spectrum beta-lactamase Escherichia coli (CTX-M) on dairy farms in North West England and North Wales

This study investigated the potential spread of CTX-M-14 Escherichia coli from a known ESBL E. coli positive farm and risk factors for the presence of CTX-M E. coli on dairy farms. Between November 2009 and March 2010, 65 farms in North West England and North Wales were visited and animals sampled for E. coli producing CTX-M ESBLs. Seventeen of these were known to have received animals from a known ESBL E. coli positive 'index' farm since 2005 (linked farms). The prevalence of CTX-M E. coli in the population of linked farms was 58.8% (10/17; CI(95%) 32.9-81.6%) and in the randomly selected control population was 35.4% (17/48; CI(95%) 22.2-50.5%). There was no significant (p>0.05) linkage for the detection of any CTX-M E. coli or specifically a CTX-M-14 E. coli to the index farm. Group 1 (CTX-M-15, CTX-M-55, CTX-M-1, CTX-M-32), group 2 (CTX-M-2) and group 9 (CTX-M-14, CTX-M-14B, CTX-M-27) CTX-M E. coli were identified on the study farms. Molecular analysis revealed that three plasmids from linked farms had similar sizes (95kbp), replicon type (IncK) and backbone genes as that from the index farm. Logistic regression analysis revealed that farms that had used a 3rd or 4th generation cephalosporin (ceftiofur, cefoperazone and cefquinome) in livestock in the last 12months were nearly 4times more likely to have ESBL E. coli present (p=0.037; OR=3.93). There was no significant association between presence of CTX-M E. coli and the use of any 1st or 2nd generation cephalosporins. Several other risk factors for the presence of CTX-M E. coli were identified, such as storage of slurry in a pit, operating an open herd policy and infrequent cleaning of calf feeding equipment.     

Prednisolone therapy for atopic dermatitis is less effective in dogs with lower pretreatment serum 25-hydroxyvitamin D concentrations

Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured in 20 dogs with atopic dermatitis prior to treatment with a standard therapeutic dosage of prednisolone (0.93-1.06 mg/kg) every other day for 5 weeks after 7 days of treatment with the same dosage once daily. The severity of their physical signs was scored before and 6 weeks after prednisolone treatment by the canine atopic dermatitis extent and severity index version 3 (CADESI-03) and the Edinburgh Pruritus Scale (EPS). The 20 dogs with atopic dermatitis that were treated with prednisolone did not have significantly lower serum concentrations of 25(OH)D than a group of 36 healthy dogs, and the physical severity of the atopic dermatitis was not correlated to pretreatment serum 25(OH)D concentrations. However, dogs which had a marked improvement of their physical signs, defined by a post-treatment EPS score of 0 and/or an 85% reduction in CADESI-03 score, had significantly higher pretreatment serum 25(OH)D concentrations than dogs with a suboptimal response (P = 0.003 and P = 0.03, respectively). Serum 25(OH)D concentrations were also measured in a previously published cohort of atopic dogs that were treated with ciclosporin. This cohort of dogs was recruited in a similar time frame to the prednisolone-treated dogs, and all samples were handled in the same way. In contrast to the prednisolone-treated dogs, there was no significant difference in 25(OH)D concentrations in dogs that responded optimally to ciclosporin compared with suboptimal responders. Additional studies are required to establish whether vitamin D has a synergistic therapeutic effect with prednisolone in dogs with atopic dermatitis.     

Characterization of the origin and body of the normal equine rear suspensory ligament using ultrasonography, magnetic resonance imaging, and histology

The suspensory ligament is difficult to image accurately, partly because it contains ligamentous fibers, as well as noncollagenous adipose and muscle tissue in the normal horse. Our hypothesis was that magnetic resonance (MR) imaging would be more accurate than ultrasonography in identifying the size of the suspensory ligament and the presence and size of noncollagenous tissues within the ligament. Eleven horses were used for ultrasonographic and MR imaging and histologic evaluation of the rear suspensory ligament. The origin and body of the normal suspensory ligament had a heterogenous appearance on MR images with two separate islands of mixed signal intensity evident throughout its otherwise hypointense cross-sectional area. Histologically, there were isolated islands of muscle, adipose, loose connective tissue and dense collagenous partitions, organized in two separate bundles that extended through the full length of the suspensory ligament origin and body to the level of its bifurcation. Comparison of MR images with corresponding histologic sections confirmed that islands of heterogenous signal intensity in normal suspensory ligaments correlated well with these bundles. Using ultrasonography, it was impossible to distinguish these islands from surrounding dense collagenous tissue consistently. MR imaging determined the cross-sectional area of the suspensory ligament more accurately than ultrasonography. Based upon these results, MR imaging is superior to ultrasonography for assessment of the suspensory ligament. The appearance associated with normal ligament anatomy needs to be understood before MR signal variation can be considered as indicative of disease in the suspensory ligament.     

Prednisolone is associated with an increase in serum insulin but not serum fructosamine concentrations in dogs with atopic dermatitis

The aim of this study was to assess the effects of a standard therapeutic protocol of prednisolone (Pred) on glucose homeostasis in atopic dogs and compare it with previously published data for ciclosporin A (CsA). The central aim of the study was to assess and compare the effects of standard therapeutic protocols of prednisolone (Pred) and ciclosporin A (CsA) on glucose homeostasis in dogs with atopic dermatitis (CAD). Both treatments significantly reduced the physical signs of CAD, as determined by the canine atopic dermatitis extent and severity index version 3 (CADESI-03) and the Edinburgh Pruritus Scale (EPS). Post-treatment plasma glucose concentrations were not significantly different in the two groups, but serum insulin concentrations were significantly higher following Pred therapy (P<0.05). Serum fructosamine concentrations were not significantly different pre- and post-treatment with Pred, although previous studies had shown that CsA treatment increased fructosamine concentrations (P<0.005). The two treatment groups were recruited in a similar timeframe, were numerically matched and there were no differences in CADESI-03 and EPS scores between the CsA and Pred groups either before or after treatment. Thus, both CsA and Pred treatment were associated with mild disturbances in glucose metabolism, but only CsA therapy resulted in a significant increase in fructosamine concentrations. This information may be relevant to clinicians when considering therapeutic options for dogs with atopic dermatitis which already have impaired glucose homeostasis.     

Does Shrub Removal Increase Groundwater Recharge in Southwestern Texas Semiarid Rangelands?

Evapotranspiration (ET) is a key component limiting groundwater recharge past the root zone in semiarid regions. Vegetation management may alter groundwater recharge if ET is altered due to changes in vegetation type or cover. This study quantifies changes in groundwater recharge following vegetation cover change from native woodland to pasture in a semiarid region of southwest Texas. The Carrizo–Wilcox aquifer is a valuable groundwater resource in this area, where overuse by dependent farming practices has lowered aquifer levels significantly in the last 85 yr. Combining data from short-term (30 mo) monitoring of the changes in soil moisture and long-term (5–30 yr) changes in total soil chloride indicated deep drainage increased slightly where land had been cleared of vegetation. Annual recharge rates below rooting depths (standardized to 155 cm) averaged only 0.72 ±  mm · yr^-1 (mean ± SE) in areas not cleared of woody vegetation, as estimated by chloride mass balance. Upon clearing, 72% of the total chloride naturally occurring in the soil profile was flushed away within 30 yr, leading to an estimated 2.59 ±  mm · yr^-1 additional recharge. Deep soil moisture in recently cleared land increased by up to 17% during the growing season of wet years (double the average rainfall) but did not increase in dry or normal precipitation years, providing supporting evidence that more water penetrated below the roots under certain environmental conditions. These results demonstrate that brush management can increase recharge by modest, but measurable, amounts depending on site-specific soil characteristics and degree of reduction in vegetation.