Perivascular wall tumour presenting as pastern mass in a Standardbred gelding

A 2-year-old Standardbred gelding was referred for a mass on the palmaromedial right front pastern which was accompanied by progressively worsening lameness. The mass was firm to palpation and covered by normal skin. Ultrasonographically, a smooth encapsulated mass was present, medial to the flexor tendons and palmar to the neurovascular bundle. Because of a poor prognosis for future athletic performance without surgical or chemotherapeutic intervention and economic constraints preventing further diagnostics and treatment, the horse was euthanised. Post-mortem magnetic resonance imaging, histopathology and immunohistochemistry revealed the mass to be a perivascular wall tumour, the first record of such a neoplasia in the horse.     

In vitro characterization andin vivo detection ofRigidoporus lignosus,the causal agent of white root disease inHevea brasiliensis,by ELISA techniques

The aim of these studies is to develop a method for early detection ofRigidopoms lignosus (Basidiomycete, Polyporaceae), the causative agent of white root disease of rubber tree. Two polyclonal sera were produced against soluble mycelial proteins of twoR. lignosus isolates, one from Africa (FCI2), the other from Asia (FID2). The specificity of the antisera was tested using isoelectric focusing (IEF)/Western-blot and DAS-ELISA. The two sera recognized all 20R. lignosus isolates from various geographical origins. The banding patterns obtained by Western-blot enabled a distinction to be made between isolates from Africa and those from Asia. In DAS-ELISA and Western-blot analyses, strong cross reactions were observed withR. ulmarius. Only slight reactions were observed in Western-blot analysis toR. lineatus andP. noxius, both causative agents of root rot inHevea. These cross reactions were not observed under our DAS-ELISA analysis conditions. Finally, no cross reactions were obtained with 9 otherPolyporaceae orHevea root pathogen species. The sensitivity threshold of the DAS-ELISA method was 5 ng ml^–1 ofR. lignosus protein. An initial approach to using the DAS-ELISA test for the detection ofR. lignosus in infected plants was carried out on artificially inoculated root samples. The DAS-ELISA protocol enabled detection ofR. lignosus in the root systems of diseased plants. Moreover, no cross reaction was observed with healthy plant extracts.     

Prognosis following surgical excision of canine cutaneous mast cell tumors with histopathologically tumor-free versus nontumor-free margins: a retrospective study of 31 cases

The purpose of this study was to determine if the presence of histopathologically tumor-free versus nontumor-free margins was prognostic for relapse or tumor-related death in dogs following surgical excision of single or multiple cutaneous mast cell tumors confined to the skin without evidence of metastasis to lymph nodes or other noncutaneous sites. Differences in tumor-related death or frequency of relapse between the two groups were not significant. Failure to achieve histopathological tumor-free margins frequently did not lead to local relapse. All tumor-related deaths occurred following local relapse. The lack of statistical support for an association between prognosis and histopathological tumor-free versus nontumor-free margins may be a result of small sample size.     

Trees and windbreaks in the Sahel: establishment,growth, nutritive,and calorific values

Tree and windbreak species considered for the Southern Sahelian Zone (SSZ) of West Africa have to be evaluated following multiple criteria such as fast establishment, shelter efficiency, production of feed for livestock, and firewood. An on-station experiment was conducted on a sandy soil in southwest Niger between 1988 and 1993 to assess the establishment, growth, nutritive, and calorific values of seven species considered for windbreaks:Andropogon gayanus, Bauhinia rufescens, Acacia holosericea, Acacia nilotica, Acacia senegal, Faidherbia albida, andAzadirachta indica. Mortality and stem diameter were monitored twice a year. From 20 months after planting (MAP) onwards, species were annually trimmed to 2 m height and to 1 m sidewards of the main stem. Fresh and dry weight of leaves, twigs, wood, and fruits were recorded. Leaves were analyzed for crude protein (CP) and metabolizable energy (ME) content. Wood was analyzed for its gross calorific value and its ash content. At 56 MAP, all species had less than 5% morality, except forA. holosericea, which had a mortality rate of 15.9%.A. indica andA. holosericea showed the highest stem diameter among species with 12.2 and 11.8 cm, respectively, at 56 MAP.A. senegal had the highest dry matter production with 22.3 t ha^–1 at 56 MAP, followed byA. indica (12.0 t ha^–1),A. holosericea (11.7 t ha^–1) andB. rufescens (11.2 t ha^–1), butA. holosericea was most productive at earlier harvests. OnlyA. senegal (6.4 t ha^–1) andA. indica (5.1 t ha^–1) had a significant wood production, whereasA. holosericea (5.7 t ha^–1) had the highest phyllodes production. Leaves ofA. senegal andA. indica had highest CP contents of 258 and 214 g kg^–1, respectively. The leaves of all species exceptA. gayanus had a higher CP:ME ratio than natural pasture in the region. The calorific values of firewood did not differ significantly among the species.A. nilotica, the species with one of the lowest firewood production, had the highest Fuelwood Value Index of 6.6. The choice of species for planting trees and windbreaks in the SSZ must be oriented along these criteria. Further research should be directed towards cost-benefit analyses, land tenure and property rights in combination with surveys on local knowledge of rural people.     

Impact of Endocrine‐Disrupting Chemicals on Reproductive Function in Zebrafish (Danio rerio)

The prevalence of endocrine‐disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex‐steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild‐type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure.     

The prevalence of itchmite, Psorergates ovis, among sheep flocks with a history of fleece derangement

An investigation of sheep flocks in the main sheep raising areas of New South Wales showed that the itchmite Psorergates ovis was frequently associated with fleece derangement. In 26 of the 41 flocks examined, P. ovis was the only ectoparasite detected. P. ovis and the sheep body louse Damalinia ovis, were found in 5 flocks. No external parasites were found on sheep examined from the 10 remaining flocks. The type of fleece derangement most frequently recorded was rubbing which in some cases was combined with areas of chewed fleece. Among flocks, there were positive relations between the prevalence of fleece derangement and prevalence of itchmite or scurf and between itchmite count and mean scurf score. Within flocks, itchmite infested sheep or sheep with scurf had higher prevalences of fleece derangement than sheep on which no mites or no scurf were found. Itchmite infested sheep had a higher prevalence of scurf than those with no detectable mite infestation. There were no significant differences in itchmite populations or fleece derangement between untreated flocks and flocks treated with synthetic pyrethroids, organophosphates or arsenic and rotenone.