Hepatic microvascular dysplasia in dogs: a retrospective study of 24 cases (1987-1995)

Hepatic microvascular dysplasia (HMD) is a disease involving a microscopic shunting of blood through the liver without the presence of a macroscopic portosystemic shunt (PSS). Data was collected from medical records and telephone conversations with referring veterinarians and owners of 24 dogs diagnosed with HMD. Criteria for diagnosis included histopathological evidence of microvascular dysplasia on hepatic biopsy as well as surgical exploration and a normal mesenteric portogram to rule out a macroscopic PSS. Dogs with HMD frequently have less severe clinical signs and a better long-term prognosis than do those with a PSS that are managed medically.     

Hypercalcemia in a dog: a challenging case

An 18-month-old, spayed female, mixed-breed dog was referred for investigation of persistent hypercalcemia. After extensive diagnostic evaluation, a tentative diagnosis of occult lymphosarcoma (LSA) was made and the dog was euthanized. At necropsy, infection with Heterobilharzia americana was diagnosed. In endemic areas, schistosomiasis should be included in the differential diagnosis of hypercalcemia, and a fecal examination should be performed in every dog with a hypercalcemia of unknown origin.     

Phenotypic characterisation of Phaeoacremonium and Phaeomoniella strains isolated from grapevines: enzyme production and virulence of extra-cellular filtrate on grapevine calluses

Extra-cellular enzyme production of different Phaeoacremonium spp. and Phaemoniella chlamydospora isolates were used to assay the possibility of inter-specific characterisation. Isolates of Phaeoacremonium aleophilum, Phaeoacremonium angustius, P. viticola and Ph. chlamydospora were grown on solid media and the activities of extra-cellular amylases, lipases, proteases, cellulases, xylanases, laccase, polygalacturonase, pectate lyase, lignin peroxidase, manganese peroxidase, urease and chitinase were assayed. Phaeoacremonium species showed activities of a larger number of enzymes and also enzyme activity was frequently higher suggesting that Phaeoacremonium can be more virulent. To assay if the produced extra-cellular enzymes could reflect the virulence capacity of the two genera, calluses of Vitis vinifera L. (cvs. Baga and Maria Gomes) and of a rootstock (R3309) were inoculated with filtrated culture liquid medium of three isolates of Ph. chlamydospora and one of P. angustius. Filtrates from all strains decreased callus growth and membrane integrity, while soluble protein content of calluses decreased with the strains CAP 054 and 1AS. P. angustius (CAP 054) induced the more severe symptoms in all genotypes. Water content decreased together with an increase of osmolality in both cultivars but not in rootstock suggesting that osmorregulatory capacity is more affected in cultivars. Data show that: (1) Phaeoacremonium and Phaeomoniella genera have different patterns of extra- cellular enzymatic production; (2) these fungi produce extra-cellular compound(s) that induce(s) senescence symptoms in plant cells inhibiting callus proliferation; (3) among the strains tested in plant calluses the most virulent isolate (CAP 054) also produced higher amounts of some extra-cellular enzymes; (5) rootstock calluses were less sensitive to inoculation than grapevine calluses.     

Clinical and anatomical features of lymphosarcoma in 118 cats

Objective To determine patients' characteristics and anatomical distribution of lesions in cats with lymphosarcoma. Design Prospective multi-institutional study of naturally occurring feline lymphosarcoma. Methods Veterinarians in Sydney were provided with free diagnostic laboratory services for suspect cases of feline lym-phosarcoma. Lymphosarcoma was diagnosed based on physical findings, radiographic and/or ultrasonographic images and results of cytological or histopathological examination. When owners were not interested in pursuing an antemortem diagnosis, suspect cases were collected for necropsy. Patients' characteristics and physical findings were recorded. A modified scheme for anatomical classification of lesions was devised including a ‘mixed’ category for cases which involved two or more anatomical forms. Results One hundred and eighteen cases were accrued over an 18 month period. The median age was 120 months and range 5 to 212 months. Age distribution was bimodal, with a small peak for cats less than 24 months, and a normal distribution centred on 97 to 120 months. Eighty cats were domestic crossbreds, 22 were Siamese or Oriental cats (including crosses), 6 were Burmese, 5 were purebred longhairs and the remaining 5 were one of a number of purebred shorthaired breeds. In comparison to 1017 consecutive cases admitted to our hospital for conditions other than lymphosarcoma, Siamese/Oriental cats were over-represented amongst lymphosarcoma cases (P = 0.0006). Male cats were also over-represented, accounting for 72 of 118 cases (P = 0.05). Abdominal lymphosarcoma was the most common anatomical form (43 cats), followed by mixed (39), nodal (20), mediastinal (9) and atypical (involving non-lymphoid organs, 7) forms. When analysed for specific organ involvement, 29 (25%) had mediastinal involvement, 71 (60%) had abdominal involvement including 60 (51%) with involvement of the intestinal tract and/or mesenteric lymph nodes and 36 (31%) with bilateral renal involvement, and 47 (40%) had peripheral lymph node involvement. No case of primary lymphoid leukaemia was identified. A noticeable subgroup of cats younger than 24 months had involvement of the anterior mediastinum with or without concurrent enlargement of cervical or axillary lymph nodes; Siamese/Oriental cats were over-represented in this subgroup. Among cases with nodal involvement, lymph nodes of the head and neck were frequently involved, mandibular nodes most commonly, followed by superficial cervical nodes. In seven cases a solitary node was affected. Conclusions Compared with similar surveys overseas, our cats were older and male cats were over-represented. There was a notable subgroup of young cats with mediastinal involvement. Siamese/Oriental cats were over-represented in this subgroup as well as in the larger population of cats with lymphosarcoma. Compared with overseas surveys, renal involvement, mixed cases and atypical cases (including nasal lymphosarcoma) were more common. A new subcategory of nodal lymphosarcoma, with involvement restricted to node(s) of head and neck, was identified.     

Lymphoid neoplasia in the koala

Objective Correlation of immunophenotype with history, anatomical and morphological features of lymphoid neoplasia in the koala.
Methods Routine necropsies were performed on 51 koalas with suspected lymphoid neoplasia between 1986 and 1997 in New South Wales and Queensland. Immuno-phenotyping was by an immunoperoxidase method utilising species cross-reactive antibodies raised against human lymphocytes and an antibody raised against koala IgG. Cases were classified according to organs and tissues affected and the morphological features of neoplastic cells.
Results Twenty-six (51%) of the cases were of the T cell immunophenotype, 12 (24%) were of B cell immunopheno-type and 13 (25%) did not stain. The age and sex of koalas did not correlate with immunophenotype (P = 0.686 and P = 1.000, respectively). Thirty-two cases were leukaemic and 36 had multiple organ involvement, probably reflecting presenta tion of koalas at advanced stages of disease. Abdominal tissue involvement was most common (44 cases), followed by nodal (32), atypical (21) and cervicomediastinal (14). The T cell immunophenotype was over-represented among the leukaemic cases (P = 0.013). Generally, the T cell immunophenotype predominated except for many affected atypical tissues. Neoplastic cells were mostly of medium nuclear size with round to oval nuclei. No correlations were found for cell morphology, mitotic index and immunopheno-type.
Conclusion The prognostic value of an immunopheno-typic, anatomical and morphological basis for the classifica tion of lymphoid neoplasia in the koala currently is limited by the need to detect these neoplasms at an early age, the requirement for freshly fixed tissues and the restricted range of available cross-reacting antibodies.     

Diversity among isolates of Actinobacillus equuli and related organisms as revealed by ribotyping

Objective The objective of this work was to examine the diversity within Australian isolates of Actinobacillus equuli and related organisms by the genotypic method of ribotyping.
Design Ribotyping, performed using the enzyme Hae III, was used to examine the diversity in 12 field isolates of A equuli (five being capable of fermenting L-arabinose), one field isolate of Pasteurella caballi and two unclassifiable field isolates. Isolates were obtained from Australian horses, except for three isolates of A equuli (one L-arabinose positive and two L-arabinose negative) which were obtained from horses and a pig in Africa. In addition, the type strains for A equuli and P caballi and a reference strain for Bisgaard Taxon 9 were included in the study.
Results The ribotype patterns were analysed by computerised cluster analysis, yielding five clusters (A to E). All five of the L-arabinose positive A equuli were assigned to cluster A, with all the other seven A equuli isolates (all L-arabinose negative) and the type strain being assigned to cluster B. One of the two unclassified isolates formed cluster C along with the reference strain for Bisgaard Taxon 9. The remaining unclassified isolate formed cluster D. Cluster E consisted of the field isolate and reference strain of P caballi .
Conclusion The results of this study indicate that A equuli is a diverse species, with L-arabinose positive isolates of A equuli being quite distinct from typical L-arabinose negative isolates. Ribotyping appears to be a useful tool in confirming the identity of A equuli -like organisms from horses.     

Snake bites recorded by veterinary practices in Australia

Objective To determine the extent of the snake bite problem in domestic animals, its regional significance and the effects of antivenom treatment.
Design A questionnaire was designed seeking information on the number and type of domestic animals referred, whether treated or untreated, type of snakes and management of the bite.
Procedure The survey form was sent to 10% of veterinary surgeons, selected at random throughout Australia.
Results The response of 106 veterinary surgeons revealed that snake bite in domestic animals is frequent, with an estimated 6200 cases reported annually. Bites were more prominent in rural (78%) than urban areas (22%) with brown, tiger and black snakes accounting for 76%, 13% and 6% of cases, respectively. Cats and dogs were the most frequently reported victims. Ninety-one percent of cats and 75% of dogs survived following the administration of antivenom whereas 66% of cats and 31% of dogs survived without antivenom. Overall, in 33% of cases antivenom was not used, and venom detection kits were used in only 1% of cases. A number of drugs were used in various combinations with or without antivenom and intravenous fluids in the treatment of animals with snake bite, but their role in reducing the severity of envenomations was not assessed.
Clinical implications Antivenom significantly improves the chances of survival of domestic animals bitten by snakes.     

Diabetes mellitus in a koala (Phascolarctos cinereus)

Objective To describe a case of diabetes mellitus in a koala (Phascolarctos cinereus).
Design A case report with controls.
Procedures We describe clinical and laboratory findings in a 6-year-old, free-living, female koala presented with traumatic injury and subsequently found to have polydipsia, hyperglycaemia and glucosuria. Over a 5 week period, serum biochemical analyses, haematological examinations, urinal-yses, measurement of serum insulin and fructosamine concentrations, necropsy, histopathological examination of a range of tissues and immunohistochemical examination of the pancreas for insulin-containing cells were done. For reference purposes, serum insulin and fructosamine concentrations were determined in four and two healthy koalas, respectively, and three healthy koalas pancreases were examined histo-logically and immunohistochemically.
Results The koala had persistent hyperglycaemia, hyperlipidaemia, hyponatraemia, hypochloraemia and glucosuria. Serum insulin concentration of the diabetic koala was only marginally smaller than that of healthy koalas, but all concentrations were smaller than reference concentrations in dogs and people. Fructosamine concentration did not allow the diabetic koala to be distinguished from healthy koalas and concentrations of all koala analytes were greater than expected for healthy dogs and people. Histopathological examination revealed extensive degeneration of pancreatic islet cells and fatty infiltration of hepatocytes. Immunoperoxidase staining revealed decreased or absent insulin in the b cells of the affected koala.
Conclusion Clinical signs, clinicopathological results and histopathological changes were consistent with diabetes mellitus. The pathogenesis of the condition could not be determined but may have been related to the administration of a parenteral corticosteroid preparation, the stress of capture or tissue damage and inflammation.