Extreme neutrophilic leucocytosis and intrathoracic mass in a Fox Terrier

Extract

An 8-year-old female Fox Terrier was presented for acute anorexia and depression. A haemogram revealed extreme neutrophilic leucocytosis (136×10⁹/L neutrophils). By Day 4, the neutrophilia was more marked (214×10⁹/L segmented; 23×10⁹/L band). Imaging revealed a cranial mediastinal mass, pleural effusion and small pneumothorax. Needle aspiration of the mass showed cells resembling malignant histiocytes against a background of mature neutrophils. On Day 7, the mass was surgically removed. Histologically, it revealed a malignancy suggestive of histiocytic sarcoma intensely infiltrated with neutrophils. Immunocyto-chemical investigations are pending. Post-operatively, the dog's appetite and demeanour improved but breathing was laboured, and neutrophilia persisted (300×10⁹/L on Day 14). The dog was humanely killed on Day 14; post mortem examination revealed no distant metastases. This dog's illness is strongly reminiscent of a rare human condition, inflammatory malignant fibrous his-tiocytoma with leukaemoid reaction (IMFH-LR). In IMFH-LR, neoplastic cells produce cytokines that attract neutrophils to the tumour. Other cytokines stimulate the bone marrow to produce extreme neutrophilia. Although paraneoplastic neutrophilia has previously been described in dogs, this is an extreme example and the condition has not previously been associated with histiocytic or intrathoracic malignancies.     

Reduced risk of acute poisoning in Australian cattle from used motor oils after introduction of lead-free petrol

Lead (Pb) poisoning of cattle has been relatively common in Australia and sump oil has been identified as an important cause of Pb toxicity for cattle because they seem to have a tendency to drink it. Lead-free petrol has been available in Australia since 1975, so the aim of this study was to assess the current risk to cattle from drinking used automotive oils. Sump or gear box oil was collected from 56 vehicles being serviced. The low levels of Pb found suggest that the removal of leaded petrol from the Australian market as a public health measure has benefited cattle by eliminating the risk of acute poisoning from used engine oil.     

Effects of drug residues in the faeces of cattle treated with injectable formulations of ivermectin and moxidectin on larvae of the bush fly, Musca vetustissima and the house fly, Musca domestica

Objective: To assess the toxicity of residues of ivermectin and moxidectin in cattle faeces collected at intervals after treatment.
Design: Replicated bioassays of faeces using larvae of the bush fly, Musca vetustissima and the house fly, Musca domestica .
Animals: Two groups of five Murray Grey x Aberdeen Angus steers were treated with injectable formulations of ivermectin and moxidectin respectively. A third group was used as an untreated control.
Procedure: Newly emerged fly larvae were reared in the dung of treated animals.
Results: Drug residues in faeces collected 3 to 35 days after treatment with an injectable formulation of moxidectin had no significant effect on the survival of larvae of M vetustissima . Similarly, faeces dropped up to seven days after treatment caused no significant reduction in larval survival in M domestica . In day 2 dung, residues of moxidectin delayed development of M vetustissima larvae, but had no effect on their survival. In contrast, ivermectin-treated steers, produced dung that inhibited larval development of both M vetustissima and M domestica for 7 to 14 days after treatment. Significant reductions in survival of M vetustissima larvae occurred in dung collected on days 21 and 28 after treatment, but by day 35 survival did not differ from that in control dung.
Conclusion: Excreted faecal residues of moxidectin are relatively innocuous to larvae of both M vetustissima and M domestica . Those of ivermectin inhibit survival for 7 to 14 days after treatment and are likely to have adverse effects on non-target organisms.     

Melting of (Mg,Fe)2SiO4 at the Core-Mantle Boundary of the Earth

The lower mantle of the Earth is believed to be largely composed of (Mg,Fe)O (magnesiowustite) and (Mg,Fe)SiO3 (perovskite). Radiative temperatures of single-crystal olivine [(Mg0.9,Fe0.1)2SiO4] decreased abruptly from 7040 +/- 315 to 4300 +/- 270 kelvin upon shock compression above 80 gigapascals. The data indicate that an upper bound to the solidus of the magnesiowustite and perovskite assemblage at 4300 +/- 270 kelvin is 130 +/- 3 gigapascals. These conditions correspond to those for partial melting at the base of the mantle, as has been suggested occurs within the ultralow-velocity zone beneath the central Pacific.     

Finding the mutation responsible for inherited rickets in Corriedale sheep

Inherited rickets of Corriedale sheep is of simple autosomal recessive inheritance. The gross and histological lesions include segmental thickening of physes, persistence of hypertrophic chondrocytes at sites of endochondral ossification, excessive osteoclastic resorption, microfractures and wide unmineralised osteoid seams lining trabeculae and filling secondary osteons. Initial testing revealed concentrations of 25-hydroxyvitamin D₃ were normal, but those of 1,25-dihydroxyvitamin D₃ were increased in serum of affected sheep, suggesting a defect in the vitamin D receptor. However, in vitro studies on cultured skin fibroblasts revealed normal binding and function of the vitamin D receptor.

A genome-wide association study was conducted using the Illumina OvineSNP50 BeadChip. A homozygous region of 199 consecutive single-nucleotide polymorphism loci was identified in affected sheep, covering a region of 10 megabase pairs on ovine chromosome 6. Of the 91 candidate genes in this region, dentin matrix protein 1 gene (dmp1) was considered the most likely as it is known to play critical roles in osteocyte maturation and mineral metabolism. Sequencing of DNA from carriers showed a nonsense mutation 253T/C in dmp1. This T/C transition introduced a stop codon (R145X) that could truncate C-terminal amino acids. Using PCR restriction fragment length polymorphism for this mutation, genotyping showed that all affected sheep were “TT” genotypes, and phenotypically normal sheep were either “CT” or “CC”. These findings suggest that a mutation in dmp1 is responsible for inherited rickets of Corriedale sheep. A simple diagnostic test is currently being designed to identify carriers with the defective “T” alleles.     

Necrotising fasciitis associated with Escherichia coli in a dog

CASE HISTORY: Lameness and limb pain associated with a laceration in the inner thigh of a Border Collie dog progressed over 4 days to extensive necrosis of the full-thickness of skin and subcutaneous (S/C) tissue. A successful outcome was achieved using surgical debridement and intensive supportive care, followed by limited local closure, axial pattern flap development, and free skin grafting.

CLINICAL FINDINGS: Clinical findings included severe pain, depression, pyrexia and hypoalbuminaemia, and full-thickness loss of skin from the caudal thigh to the hock. Histopathologically, debrided tissue showed extensive necrosis of the dermis, adipose and muscle tissues, and the presence of numerous Gram-negative rods. Escherichia coli was cultured from deep tissue samples.

DIAGNOSIS: Necrotising fasciitis (NF) associated with E. coli infection.

CLINICAL RELEVANCE: NF associated with E. coli has not been previously reported in dogs. The importance of early diagnosis and surgical debridement is noted and the relevant medical literature is reviewed.     

Suspected inherited rickets in Corriedale sheep

A suspected inherited form of rickets was diagnosed in Corriedale sheep on a commercial sheep farm in Marlborough. Affected lambs were normal at birth but showed a reduced growth rate and a range of skeletal abnormalities, including both varus and valgus deformities and a characteristic dip in the shoulder region. Up to 20 affected lambs had been born on the property over the last two seasons. Skeletal lesions in affected lambs included swollen costochondral junctions, moderate to marked thickening of physes in long bones, and collapse of weakened subchondral bone, particularly in the proximal humerus. These lesions, together with the microscopic changes, strongly suggested a diagnosis of rickets. Affected lambs were hypocalcaemic and hypophosphataemic, consistent with a deficiency of vitamin D.

Vitamin D assays revealed significantly higher 1,25(OH) vitamin D concentrations in affected lambs than in controls, suggesting a defect in the vitamin D receptor as the likely mechanism. DNA testing revealed that 4/10 Corriedale rams used during the previous season had sired affected lambs. Studies aimed at confirming the genetic nature of the disease and the mechanism are continuing at Massey University.