Progressive ataxia associated with degenerative thoracic myelopathy in Merino sheep

A neurological disorder in Merino sheep, characterised clinically by progressive posterior ataxia and microscopically by Wallerian degeneration in thoracic segments of the spinal cord, is described. Animals of both sexes were affected, with the earliest onset of disease being at 5 months of age. Most affected animals died before 2 years of age. The clinical, pathological and epidemiological features suggest that this degenerative thoracic myelopathy is a previously unrecognised entity differing from other reported causes of ataxia in sheep in Australia.     

Evaluation of B-lymphocyte levels and functions in gnotobiotic dogs.

Quantitative and qualitative aspects of B-lymphocyte functions in gnotobiotic dogs and conventional dogs were determined. Using 3 different methods to identify B-cells by surface markers and 3 different methods to measure immunoglobulins (eg, serum electorphoresis, immunoelectrophoresis, and radial immunodiffusion), it was determined that gnotobiotic dogs were B-cell deficient. Related studies, however, indicate that the capacity to develop humoral immune responses was unimpaired. It is presumed that lack of immunogenic stimulation within the gnotobiotic isolation units accounts for this observation.     

Comparison of Thoroughbred Growth Data to Body Weights Predicted by the NRC

The National Research Council (NRC) recently published a method for calculating expected body weight (BW) in growing horses. The objective of this study was to compare foal BW data obtained from commercial Thoroughbred (TB) farms with BW estimates obtained using the 2007 NRC equation. A total of 9,589 observations on 885 growing TB horses were obtained. Data were sorted by age, and a subset was used for statistical analysis. Comparisons between actual BW and 2007 NRC-predicted BW at each month (0–18 months of age) were made using paired t-tests. The 2007 NRC closely predicted BW of growing TB horses at birth and between 6 and 9 months of age (within 3 kg). However, the equation underestimated BW between 1 and 5 months of age (by as much as 10 kg) and overestimated BW between 10 and 13 months of age (by as much as 9 kg). The 2007 NRC also underestimated BW by as much as 9 kg between 15 and 16 months of age. In the current study, the 2007 NRC equation did not precisely predict BW of horses at all ages. The 2007 NRC equation predicts that daily gain will decrease over time, whereas foals in the current study had an increase in daily gain between 12 and 14 months of age. Foals in the current study were raised in pasture-based management systems in which variations in forage availability and quality could have resulted in fluctuations in growth rate.     

Tumour angiogenesis,anti‐angiogenic therapy and chemotherapeutic resistance

In order for a tumour to continue to grow and disseminate, it must acquire a new blood supply. Neovascularisation can be enacted by a number of different mechanisms. This dependence of tumour progression on an augmented vascular supply has been exploited by the development of anti‐angiogenic drugs, which are designed to inhibit new blood vessel formation or disrupt existing tumour‐associated vasculature, both leading to ischaemic–hypoxic tumour cell death. However, the clinical benefits of these therapeutic approaches are frequently variable and often transient, the neoplasm sometimes being able to use other neovascularisation mechanisms to maintain its blood supply and thus evade the current anti‐angiogenic therapy. Tumours may also develop a more malignant phenotype following this treatment. Clinical outcomes may be improved by simultaneously inhibiting different angiogenic pathways, abetted by more effective drug delivery regimens such as metronomic chemotherapy and the concurrent use of other antitumour modalities.     

Detection of Toxoplasma gondii DNA in Fresh and Frozen Semen from Rams in Brazil

The aim of this study was to estimate the prevalence of genomic DNA of Toxoplasma gondii in semen samples from commercial rams in artificial insemination centres in Brazil, as well as in fresh semen from rams in the northeast of Brazil. In total, 108 semen samples were obtained from artificial insemination centres, and genomic DNA of T. gondii was detected in 24 of 108 (22.2%). The prevalence of antibodies anti‐Toxoplasma gondii among sheep on rural properties was 9.2% (10/109), and 100% of the semen samples of these animals were positive in the PCR for T. gondii DNA. The molecular identity was confirmed through sequencing, which indicated 99.9% similarity with the T. gondii DNA sequences stored in the GenBank. This study reports the first occurrence of T. gondii DNA in the semen of rams, which came from artificial insemination centres in Brazil, as well as the occurrence of T. gondii DNA in the fresh semen of naturally infected rams in the northeast of Brazil.