Biochemical evaluation of the hepatobiliary system in dogs and cats

The causes and clinical signs of hepatobiliary involvement in disease are many and varied and often are not referable directly to this organ system. Laboratory investigation frequently is necessary to rule hepatic disease in or out, to assess the functional impact on the liver, and to decide whether hepatic disease is the patient's primary problem or a complication of something else. The selection and interpretation of laboratory tests to resolve these problems is based on an understanding of relevant functional anatomy and pathophysiology. The mainstay of such assessment is hepatic enzymology, which can detect active disease in both hepatocytes and the biliary system. The hepatocellular pattern of disease is characterized by increases in leakage enzymes such as SDH, GLDH, and ALT and the cholestatic pattern by increases in induced enzymes (ALP and GGT). In general, enzymology does not allow the intensity or functional effect of hepatobiliary disease to be assessed, and quite severe hepatopathies may have only minimal enzyme abnormalities. For this reason, the primary biochemical data base for ruling hepatobiliary disease in or out always should involve some screening tests of hepatic function, such as albumin, protein, bilirubin, glucose, or urea determinations; as well as urinalysis to search for bilirubinuria and urobilinogenuria in hyperbilirubinemic patients and for ammonium biurate crystals when hyperammonemia or hepatic encephalopathy is suspected. Because the liver synthesizes most clotting factors, evaluation of blood coagulation is indicated when surgery is contemplated on patients with liver disease or when bleeding is present. Paired pre- and post-prandial determinations of serum bile acids are the preferred method for assessment of hepatobiliary function in dogs and cats. However, the BSP clearance test continues to be useful in the functional assessment of the liver as long as the dye remains available to veterinarians. Clearance of BSP is delayed in hepatocellular, cholestatic, and portosystemic disease as well as by severe extrahepatic circulatory disturbances, In general, this functional test is less sensitive than serum bile acids or the ammonia tolerance test in the recognition of hepatic encephalopathy caused by portosystemic anomalies. The objectives of biochemical screening of the liver are to establish the type (hepatocellular, biliary, or mixed), duration (acute, chronic), and stage (aggressive, convalescent) of hepatobiliary disease and to assess functional status.(ABSTRACT TRUNCATED AT 400 WORDS)     

Protection of lambs against experimental pneumonic pasteurellosis by transfer of immune serum

Passive protection of specific pathogen-free lambs against experimental pasteurellosis was achieved using antisera from conventionally reared sheep which were either convalescent from experimental pneumonia or inoculated with Pasteurella haemolytica A2 vaccines. The complete immune sera, or immunoglobulin-rich fractions prepared from them, when administered separately or together provided 94-100% protection of recipients compared to control lambs. Antibodies to P. haemolytica in donor sera were quantified by anti-sodium salicylate extract (SSE) and anti-lipopolysaccharide (LPS) ELISA, bactericidal assay, cytotoxin neutralization and indirect haemagglutination. The anti-SSE ELISA titres correlated best with protective efficacy and could be used to measure antibody in recipient lambs immediately before challenge. The degree of protection was unaffected by prior infection with parainfluenza virus Type 3, suggesting that such exposure did not enhance exudation of circulating immunoglobulin into the respiratory tract. It was concluded that systemic humoral immunity alone can prevent pasteurellosis.     

Clinical pathology - the problem oriented approach to laboratory support in clinical veterinary medicine

An adequate diagnosis allows the development of specific treatment and preventive strategies for problems encountered in clinical practice. Such a diagnosis must sustain reasonable scientific challenge and needs to be founded on objective clinical and/or laboratory findings. The problem-oriented system optimises the chance of achieving this while making it possible to improve performance through self-assessment and through the development of a standard, rational, and comprehensive approach to the diagnosis of clinical problems. This system enhances the scientific aspects of veterinary diagnosis and is an effective means of incorporating laboratory support into clinical veterinary medicine.     

White liver disease in goats

Three field cases of ill-thrift, hepatic lipodystrophy and low tissue levels of vitamin B12 in young angora cross goats are reported. The cases meet the criteria for the diagnosis of white liver disease (WLD) described for sheep. The hypothesis that WLD is a metabolic consequence of cobalt/vit B12 deficiency in sheep and goats on a diet rich in propionate is developed, together with possible reasons for its occurrence in these species but not in cattle or red deer.     

Pancreatic endocrinopathies in ferrets.

Pancreatic endocrinopathies, especially insulinomas, are a common finding in ferrets. Surgical resection remains the treatment of choice for insulinomas because it can provide longer disease-free intervals and survival times. Because of the high rate of metastasis, owners should be advised that treatment is rarely curative and is aimed at controlling the clinical signs of hypoglycemia by stopping or slowing the progression of the insulinoma. Although less common, diabetes mellitus can occur in ferrets, but is often a postsurgical sequela to insulinoma resection. Current advancements in diabetes management can be applied to ferrets with diabetes mellitus.     

The basis of host recognition in Fusarium oxysporum f. sp. lycopersici

Filtrates from shake-cultures of Fusarium oxysporum f. sp. lycopersici race 1, concentrated to 20% of the original volume, caused cell death in tomato leaf protoplasts from near-isogenic lines corresponding to the compatible cultivar/race reactions of whole plants. Maximum activity was found in late log phase cultures on Czapek-Dox supplemented with 2% casamino acids. Selective toxicity was associated only with the protein fraction of the culture filtrate. LD₅₀ values for susceptible Ace and Moneycross to F. oxysporum f. sp. lycopersici race 1 culture filtrates were 1·92 and 0·36 μg protein ml⁻¹. Corresponding values for cvs Royal Ace and MM161, each containing the I-gene conferring resistance to race 1, were >350. Culture filtrates from F. oxysporum f. sp. lycopersici race 2 gave LD₅₀ values of 2·34 and 2·08 μg protein ml⁻¹ on cvs Ace and Royal Ace, both susceptible to race 2. The LD⁵⁰ of cv. Ace to a non-pathogenic isolate of F. xysporum f. sp. lycopersici was > 350. Culture filtrates from non-host formae of F. oxysporum were 9–149-fold less toxic on cv. Ace. Protoplasts from Pisum sativum, Lactuca sativa, Zea mays, Gossypium barbadense and Solanum melongena, all non-hosts of F. oxysporum f. sp. lycopersici, were 6–175 times less sensitive to F. oxysporum f. sp. lycopersici filtrates than susceptible tomato. The putative toxins lycomarasmin and fusaric acid showed no differential toxicity to I⁺ and I⁻ tomato protoplasts. The results are discussed in the wider context of host-pathogen interaction in which specificity is considered as the recognition of susceptibility by a proteinaceous toxic metabolite of the pathogen. This hypothesis is further extended to include the specificity of F. oxysporum formae and races.