A MYELOGRAPHIC TECHNIQUE FOR AVIAN SPECIES

A post-mortem myelogram was used to diagnose a vertebral fracture in a Red-tailed Hawk ( Buteo jamaicenis ). This diagnosis led the authors to believe that myelography would be useful in live birds. In a pilot study using live adult female chickens (Gallus domesticus) , mammalian myelographic techniques were modified for avian anatomic differences. A thoracolumbar puncture site was used rather than the lumbar or cisternal site which is commonly used in mammals. The volume of contrast medium needed to produce a diagnostic myelogram in birds(0.8–1.2 ml/kg) was found to be approximately four times that needed in mammals. A 25 gauge spinal needle was used rather than a 23 gauge needle. Myelograms of diagnostic quality were obtained with normal subject recovery. Seizures, the most common post-myelographic complication in mammals, were not observed in any of the birds studied. Avian myelography was found to be a cost effective and humane technique with potential application to avian practice.     

A screening test for subclinical liver disease in horses affected by pyrrolizidine alkaloid toxicosis

Objective: To evaluate various biochemical tests as indicators of subclinical liver disease in horses exposed to pyrrolizidine alkaloid toxicosis.
Design: A clinical pathology field study.
Animals: Twenty-two clinically normal horses from four properties in the Kimberley region of Western Australia.
Procedure: Serum samples from each horse were assayed for gamma glutamyltransferase, alkaline phosphatase and aspartate aminotransferase activities, and for serum bile acid concentration, albumin and total protein. Serum protein electrophoresis was performed and their amino acid profiles determined. Bromosulphophihalein halfclearance times were measured. Horses were then subjected to a single liver biopsy. Results were analysed by, variance of group means, the Fisher-Irwin exact test, and by sensitivity and specificity calculation.
Results: Horses were classified into 2 groups, of 10 unaffected and 12 subclinically affected, on the basis of liver histology. Significant differences between the unaffected and subclinical groups were observed for gamma glutamyltransferase and alkaline phosphatase activities (P < 0.01). Gamma glutamyltransferase had sufficient sensitivity (75%) and specificity (90%) to function as a primary screening test for subclinical liver disease in horses exposed to pyrrolizidine alkaloids. Alkaline phosphatase was useful, but with lower sensitivity (58%).
Conclusion: Serum gamma glutamyltransferase activity is a useful screening test for detecting subclinical liver disease in horses exposed to pyrrolizidine alkaloids under field conditions in northern Australia.     

Diffusion kinetics of samarium and neodymium in garnet, and a method for determining cooling rates of rocks

Experimental determinations of the diffusion coefficients of samarium and neodymium in almandine garnet and theoretical considerations show that one cannot assign a sufficiently restricted range of closure temperature, TC, to the samarium-neodymium decay system in garnet for the purpose of constraining the cooling rate. However, it is shown that the samarium-neodymium cooling age of garnet can be used to calculate both cooling rate and TC if the temperature and age at the peak metamorphic conditions are known.     

Comparison of methods used to diagnose generalized inflammatory disease in manatees (Trichechus manatus latirostris).

Manatees (Trichechus manatus latirostris) are afflicted with inflammatory and infectious disease secondary to human interaction, such as boat strike and entanglement, as well as "cold stress syndrome" and pneumonia. White-blood-cell count and fever, primary indicators of systemic inflammation in most species, are insensitive in diagnosing inflammatory disease in manatees. Acute phase-response proteins, such as haptoglobin and serum amyloid A, have proven to be sensitive measures of inflammation/infection in domestic large animal species. This study assessed diagnosis of generalized inflammatory disease by different methods including total white-blood-cell count, albumin: globulin ratio, gel electrophoresis analysis, C-reactive protein, alpha, acid glycoprotein, haptoglobin, fibrinogen, and serum amyloid A. Samples were collected from 71 apparently healthy and 27 diseased animals during diagnostic medical examination. Serum amyloid A, measured by ELISA, followed by albumin:globulin ratio, measured by plasma gel electrophoresis, were most sensitive in diagnosing inflammatory disease, with diagnostic sensitivity and specificity of approximately 90%. The reference interval for serum amyloid A is <10-50 microg/ml with an equivocal interval of 51-70 microg/ml. The reference interval for albumin:globulin ratio by plasma gel electrophoresis is 0.7-1.1. Albumin: globulin ratio, calculated using biochemical techniques, was not accurate due to overestimation of albumin by bromcresol green dye-binding methodology. Albumin:globulin ratio, measured by serum gel electrophoresis, has a low sensitivity of 15% due to the lack of fibrinogen in the sample. Haptoglobin, measured by hemoglobin titration, had a reference interval of 0.4-2.4 mg/ml, a diagnostic sensitivity of 60%, and a diagnostic specificity of 93%. The haptoglobin assay is significantly affected by hemolysis. Fibrinogen, measured by heat precipitation, has a reference interval of 100-400 mg/dl, a diagnostic sensitivity of 40%, and a diagnostic specificity of 95%.     

ASVCP guidelines: allowable total error guidelines for biochemistry

As all laboratory equipment ages and contains components that may degrade with time, initial and periodically scheduled performance assessment is required to verify accurate and precise results over the life of the instrument. As veterinary patients may present to general practitioners and then to referral hospitals (both of which may each perform in‐clinic laboratory analyses using different instruments), and given that general practitioners may send samples to reference laboratories, there is a need for comparability of results across instruments and methods. Allowable total error (TE_a) is a simple comparative quality concept used to define acceptable analytical performance. These guidelines are recommendations for determination and interpretation of TE_a for commonly measured biochemical analytes in cats, dogs, and horses for equipment commonly used in veterinary diagnostic medicine. TE_a values recommended herein are aimed at all veterinary settings, both private in‐clinic laboratories using point‐of‐care analyzers and larger reference laboratories using more complex equipment. They represent the largest TEa possible without generating laboratory variation that would impact clinical decision making. TE_a can be used for (1) assessment of an individual instrument's analytical performance, which is of benefit if one uses this information during instrument selection or assessment of in‐clinic instrument performance, (2) Quality Control validation, and (3) as a measure of agreement or comparability of results from different laboratories (eg, between the in‐clinic analyzer and the reference laboratory). These guidelines define a straightforward approach to assessment of instrument analytical performance.     

ASVCP reference interval guidelines: determination of de novo reference intervals in veterinary species and other related topics

Reference intervals (RI) are an integral component of laboratory diagnostic testing and clinical decision‐making and represent estimated distributions of reference values (RV) from healthy populations of comparable individuals. Because decisions to pursue diagnoses or initiate treatment are often based on values falling outside RI, the collection and analysis of RV should be approached with diligence. This report is a condensation of the ASVCP 2011 consensus guidelines for determination of de novo RI in veterinary species, which mirror the 2008 Clinical Laboratory and Standards Institute (CLSI) recommendations, but with language and examples specific to veterinary species. Newer topics include robust methods for calculating RI from small sample sizes and procedures for outlier detection adapted to data quality. Because collecting sufficient reference samples is challenging, this document also provides recommendations for determining multicenter RI and for transference and validation of RI from other sources (eg, manufacturers). Advice for use and interpretation of subject‐based RI is included, as these RI are an alternative to population‐based RI when sample size or inter‐individual variation is high. Finally, generation of decision limits, which distinguish between populations according to a predefined query (eg, diseased or non‐diseased), is described. Adoption of these guidelines by the entire veterinary community will improve communication and dissemination of expected clinical laboratory values in a variety of animal species and will provide a template for publications on RI. This and other reports from the Quality Assurance and Laboratory Standards (QALS) committee are intended to promote quality laboratory practices in laboratories serving both clinical and research veterinarians.     

Clinical chemistry of companion avian species: a review

Birds have evolved alternate physiologic strategies to contend with dehydration, starvation, malnutrition, and reproduction. Basic anatomic and functional differences between birds and mammals impact clinical chemistry values and their evaluation. Interpretation of the results of standard biochemical analyses, including BUN, alanine aminotransferase, aspartate aminotransferase, creatine kinase, gamma glutamyltransferase, bilirubin, ammonia, alkaline phosphatase, cholesterol, bile acids, glucose, albumin, globulins, calcium, phosphorus, prealbumin (transthyretin), fibrinogen, iron, and ferritin, is reviewed and discussed in relation to these physiological differences. The use and interpretation of alternative analytes appropriate for avian species, such as uric acid, biliverdin, glutamate dehydrogenase, and galactose clearance, also are reviewed. Normal avian urine and appropriate use of urinalysis, an integral part of laboratory diagnosis in mammalian species that frequently is omitted from avian diagnostic protocols, is discussed.