Development of an ELISA to detect circulating anti-asparaginase antibodies in dogs with lymphoid neoplasia treated with Escherichia coli l-asparaginase.

Resistance to Escherichia coli l-asparaginase in canine lymphoma occurs frequently with repeated administration, a phenomenon often attributed, without substantiation, to the induction of neutralizing antibodies. To test the hypothesis that treated dogs develop antibodies against the drug, we created an enzyme-linked immunosorbent assay (ELISA) to measure plasma anti-asparaginase immunoglobulin G responses. Using samples from dogs that had received multiple doses, specific reactivity against l-asparaginase was demonstrated, while naïve patients' samples were negative. The optimized ELISA appeared sensitive, with endpoint titers >1 600 000 in positive control dogs. Intra- and inter-assay coefficients of variation were 3.6 and 14.5%. The assay was supported by the observation that ELISA-positive plasma could immunoprecipitate asparaginase activity. When clinical patients were evaluated, 3/10 dogs developed titers after a single injection; with repeated administration, 4/7 dogs were positive. l-asparaginase antibodies showed reduced binding to the PEGylated drug formulation. The ELISA should prove useful in investigating the potential correlation of antibody responses with resistance.

A necropsy-based descriptive study of dairy cow deaths on a Colorado dairy.

Increasing levels of dairy cow mortality pose a challenge to the US dairy industry. The industry's current understanding of dairy cow mortality is reliant upon descriptions largely based on producer or veterinary assumptions regarding cause of death without the benefit of detailed postmortem evaluations. A thorough necropsy is a superior tool for establishing a cause of death, except for cases involving euthanasia for traumatic accidents or severe locomotor disorders. Information provided from a necropsy examination would be most valuable if it were categorized and combined with cow health information in a complete postmortem evaluation designed to guide future management decisions. The objective of this study was to describe dairy cow deaths on a Colorado dairy over a 1-yr period and explore classification systems for necropsy findings that might inform management actions aimed at reducing dairy cow mortality. Throughout the study period a thorough necropsy examination was performed on every cow that died. Based upon this examination each death was characterized by a proximate cause (i.e., the most likely immediate cause of the death). Each proximate cause of death was then categorized using 3 alternate schemes founded on generalized etiologic principles and influenced by previous clinical history and treatments. These schemes included the broad categories commonly used for classifying findings within a review of literature related to dairy cow mortality, a diagnostic scheme used within the problem-oriented veterinary medical record, and an analysis focusing on the primary physiologic system derangement for each death. A total of 2,067 cows were enrolled during the study period of which 1,468 cows freshened, 507 cows were sold, and 94 cows died, resulting in a mortality risk of 6.4 deaths per 100 lactations at risk. The distribution of deaths by parity was significantly different from the herd distribution at the end of study with the largest percentage of death present in parity > or =4. Postmortem findings attributable to a specific cause of death were present for all but 4 of the 94 deaths. Assignment of the proximate causes of death to categories within the 3 alternate schemes provided a means for classifying necropsy findings and causes of death with different levels of detail. Creating categories with more selective groupings may provide a means for capturing specifics related to deaths that can be used to guide management decisions.

Use of matrix metalloproteinases 2 and 9 and white blood cell counts in monitoring the treatment and predicting the survival of horses with septic arthritis.

Thirty-nine samples of synovial fluid were collected from the joints of 32 horses with suspected septic arthritis and 39 samples were collected from horses euthanased for non-orthopaedic conditions. The white blood cell counts (WBCC) were determined and the pro and active forms of matrix metalloproteinases (MMPs) 2 and 9 were measured by gelatin zymography and image analysis in each sample. The initial measurements of the ratio of proMMP9:proMMp2 and WBCC were good prognostic indicators of the survival of the horses. There was no significant relationship between the interval between the injury and the horse being referred for treatment and either the WBCC or the levels of MMP2 and MMP9 initially, and no evidence that this interval significantly affected the chances of the horses surviving.

Modified frontonasal sinus flap surgery in standing horses: surgical findings and outcomes of 60 cases.

REASONS FOR PERFORMING STUDY: Previous studies of sinus surgery on standing horses have been based on techniques which utilise powered hand bone saws and preserve the bone flap, which was thought to be essential for a good cosmetic result. This report describes a simplified technique applied to the standing horse where the sinus flap construction used a large skull trephine and where the bone flap is necessarily discarded. OBJECTIVES: To assess whether the modified standing frontonasal flap (SFF) surgery offers an effective method to investigate and/or treat sinunasal disorders in the horse. METHODS: The case records of 60 horses subjected to modified SFF surgery were reviewed to analyse the efficacy of the technique when applied to a range of sinunasal disorders in terms of diagnosis, surgical findings, complications and long-term outcomes, including cosmetic effect. RESULTS: Resolution of clinical signs was achieved in 54 out of 60 horses, and for the remainder the SFF technique proved useful on a diagnostic basis. The cosmetic result was, in the opinion of the owners, excellent or satisfactory in 48 of 56 (86%) horses. CONCLUSIONS: The modified SFF technique was found to be practicable and provided satisfactory exposure of the sinus contents for diagnosis and removal of diseased tissue in a range of disorders. An acceptable cosmetic result can be obtained in the majority of horses despite rejection of the disc of overlying bone. Apart from avoiding the risks associated with general anaesthesia, the advantages of the modified SFF sugery are: a reduction of haemorrhage in the standing horse; reduced mucosal engorgement; straightforward anatomical orientation; a comfortable working height; and reduced surgery time. A sound knowledge of the functional anatomy of the area is a prerequisite before embarking on any form of sinunasal surgery. Complications are infrequent and usually transient. POTENTIAL RELEVANCE: The modified SFF technique is a valuable alternative to other invasive methods of sinunasal surgery.

Rupture of the flexor tendons of a horse secondary to a non-responsive digital sheath sepsis.

A 12-year-old hunter gelding became severely lame as a result of a laceration to the sheath of the digital flexor tendons of its left hindlimb, but there was no apparent damage to the tendons. The injury became chronically infected with Pseudomonas and Streptococcus species and Escherichia coli which did not respond to antibiotic treatment, and the horse remained lame. A postmortem examination revealed that the tendons had ruptured.

Treatment of laryngeal hemiplegia in horses by prosthetic laryngoplasty, ventriculectomy and vocal cordectomy.

The medical records of 80 horses treated for left laryngeal hemiplegia by prosthetic laryngoplasty, ventriculectomy and vocal cordectomy were examined, first to compare the subjective and objective success rates for groups of horses of different ages and used for different purposes, and secondly, to compare the efficacy of including vocal cordectomy in the surgical protocol with published success rates for laryngoplasty and ventriculectomy alone. Subjectively, 70 per cent of the horses were said to have had a successful surgical outcome. The success rate for thoroughbred racehorses (66 per cent) was lower than for other breeds (90 per cent) on the basis of a subjective assessment by owners and trainers. Thoroughbreds two years old or younger had a success rate of 69 per cent, but older thoroughbreds had a success rate of 61 per cent. Of the 17 horses for which an objective performance index could be calculated, 10 (59 per cent) had an improved performance postoperatively. There was a nearly significant association between the objective and subjective assessments (P=0.078). Six of 69 horses (8.7 per cent) continued to make a respiratory noise after surgery. The subjective assessment of success did not appear to correlate with the objective measure of success used in this study and age had no apparent association with a successful surgical outcome. Inclusion of a vocal cordectomy in the surgical protocol may be more important in the eradication of postoperative respiratory noise than in improving clinical success rates.