Primary cutaneous extragenital canine transmissible venereal tumour with Leishmania‐laden neoplastic cells: a further suggestion of histiocytic origin?

The clinical signs and histopathological features of a primary extragenital canine transmissible venereal tumour (TVT) are described. Three subcutaneous round alopecic nodules were located on the anterior and caudal dorsal region and in the ventral area of the neck. Cytologically, tumour cells were intermediate in size with a moderate amount of cytoplasm, and the nuclei were immature with finely reticular chromatin. The cytoplasm was lightly to heavily basophilic and contained distinct small vacuoles at the periphery. On the basis of these characteristics, a diagnosis of TVT was made and confirmed by histological and ultrastructural investigations. Leishmania amastigotes were detected in the cytoplasm of macrophages and neoplastic cells of the tumoral mass. The presence of the parasite within neoplastic cells is consistent with a histiocytic origin of TVT.     

Control of canine leptospirosis in Europe: time for a change?

Changes in the formulation of the Leptospira components of dog vaccines are being considered in Europe, following changes in North America. This article discusses the options for change and recommends the continued inclusion of serovars Icterohaemorrhagiae and Canicola plus the inclusion of serovars Bratislava and Grippotyphosa (for mainland Europe only). If other serovars, such as Pomona, are to be considered in the future, then there is a need for additional clinical, cultural and serological studies across Europe to support their inclusion.     

A novel NF-κB inhibitor improves glucocorticoid sensitivity of canine neoplastic lymphoid cells by up-regulating expression of glucocorticoid receptors

Lymphoid neoplasms including lymphoma and leukemia are one of the most life-threatening disorders in dogs. Many lymphoid malignancies are well-treated with glucocorticoid (GC); however, GC resistance sometimes develops and its mechanism remains uncertain. Since constitutive activation of nuclear factor-κB (NF-κB) has been reported to play roles in lymphoid malignancies, we examined whether inhibition of NF-κB activity with a synthetic inhibitor IMD-0354 affected GC sensitivity of canine neoplastic lymphoid cells, CL-1 and GL-1. Dexamethasone failed to inhibit proliferation of these cells, in which low expression of glucocorticoid receptors (GR) was identified. In the presence of IMD-0354, GR expressions in CL-1 and GL-1 were increased, consequently dexamethasone inhibited their proliferation. These results indicated that GR expression might be down-regulated by spontaneous activation of NF-κB, resulting in GC resistance. Taken together, interference of NF-κB activity may have the synergistic effect in combination chemotherapy with GC for treatment against lymphoid malignancies.     

Expression of 14-3-3 σ protein in normal and neoplastic canine mammary gland

14-3-3 σ protein is a negative cell cycle regulator, with both reduced and elevated levels associated with cancer in humans. This study assessed the expression of this protein in canine mammary tissues using immunohistochemistry and Western blotting. 14-3-3 σ was detected in 97% of the mammary tissue samples examined and was found in both myoepithelial (MECs) and epithelial (ECs) cells. Expression levels were elevated and reduced in neoplastic ECs and MECs, respectively (P < 0.001). Intense expression of 14-3-3 σ was detected in neoplastic ECs infiltrating blood vessels and lymph nodes and suggests a possible role for this protein in the malignant transformation of mammary neoplasms. Moreover, double immunostaining for 14-3-3 σ and the MEC – specific marker p63, confirmed that 14-3-3 σ is a highly sensitive marker of MECs since all p63 – positive cells were also positive for 14-3-3 σ. However, this protein is not exclusive to MECs as ECs also labelled positively.     

Bartonellosis in cats: a role in uveitis?

Bartonellosis has been widely studied in human and veterinary medicine over the past two decades. Despite this fact, it remains an enigmatic disease in many ways. The causative bacteria, Bartonella spp, are transmitted to cats by fleas and thus the prevalence in cat populations, particularly in temperate climates, is high. Most cats, whether infected naturally or experimentally, remain asymptomatic. Thus, correlating the presence of the organism to clinical disease, including uveitis, in cats has been difficult. This review summarizes what is known of the transmission and pathogenesis of Bartonella spp in cats, the possible role of the organism in feline ocular disease, as well methods of diagnosis and treatment.     

Antiproliferative effect of α-mangostin on canine osteosarcoma cells

Osteosarcoma is the most frequently diagnosed primary bone tumor in dog. Since chemotherapeutics are quite limited due to high cost and severe toxicity, therefore, the ultimate goal is to discover cost-effective therapeutics with less toxicity. We have studied the effect of α-mangostin, a xanthone derivative isolated from pericarp of mangosteen (Garcinia mangostana Linn.) in canine osteosarcoma, D-17 cells. The results showed that α-mangostin induced antiproliferation with IC(50) at 15 μg/ml. Hoechst 33342 nuclear staining and nucleosomal DNA-gel electrophoresis revealed that α-mangostin could induce nuclear condensation and fragmentation, typically seen in apoptosis. Cell cycle analysis demonstrated that α-mangostin induced sub-G1 peak. In addition, α-mangostin also induced membrane flipping of the phosphatidylserine and the loss of mitochondrial membrane potential in D-17 cells. In conclusion, α-mangostin, induced apoptotic cell death against canine osteosarcoma D-17 cells, could be a potential candidate for preventive and therapeutic application for bone cancer treatment in dogs.     

Delayed embolization of an Amplatz® canine duct occluder in a dog

A 5-year old, 5.8 kg, castrated male Pomeranian was diagnosed with a type IIa patent ductus arteriosus (PDA) with a minimal ductal diameter of 3.5 mm and ampulla width of 7.1 mm based on angiographic assessment. A 6 mm Amplatz^® Canine Duct Occluder (ACDO) was deployed within the PDA. Once deployed, the device assumed it's native shape and back-and-forth maneuvering was performed with the delivery cable to assess device stability. Device position and complete occlusion were confirmed with both angiography and transesophageal echocardiography prior to and after release of the device. The device location was confirmed within the ductus arteriosus by echocardiography prior to discharge. The dog was discharged with instructions for strict activity restriction. Two days after discharge, the dog was left unsupervised in the backyard and shortly afterwards was found coughing with severe respiratory distress. The dog was evaluated at an emergency hospital and thoracic radiographs documented embolization of the ACDO to the main pulmonary artery along with a severe alveolar pattern throughout the right lung fields. Shortly after obtaining thoracic radiographs, the dog experienced cardiopulmonary arrest with unsuccessful resuscitation. This case describes a possible complication of transcatheter PDA occlusion with an ACDO, which has not been previously reported. An incident report, or catalog of adverse events with these devices, may prove useful in identifying additional fatal complications that others may have encountered, but are not reported in the literature. The report of this complication emphasizes the importance of strict activity restriction after device placement in dogs.     

Zinc metabolism--a factor in canine aggression?

In order to test the hypothesis of zinc-deficiency as a factor in canine aggression, we examined sera of dangerously aggressive dogs and of behaviourally normal (non-aggressive) dogs for their zinc-contents. The results showed distinctly higher zinc-concentrations (mean +/- SD) in aggressive dogs (1.69 +/- 0.49 micrograms/ml) than in normal non aggressive dogs (0.76 +/- 0.16 microgram/ml).     

Characterization of β-catenin expression in canine osteosarcoma

Osteosarcoma (OSA) is the most frequently occurring malignant primary bone tumour in dogs and children and arises from cells of the osteoblast lineage. Inappropriate Wnt signalling activity has been implicated in human OSA. Altered expression of β-catenin, an integral member of the Wnt signalling pathway, has been associated with numerous human cancers, including OSA. In this study, 30 of the 37 primary canine OSA tissues and 2 of the 3 metastatic OSAs were positive for β-catenin expression as determined by immunohistochemistry, whereas 2 normal bones stained negative for β-catenin. No mutations were identified in exon 3 of β-catenin in the three OSA cases in which DNA sequencing was performed. Finally, there was no relationship between β-catenin expression and overall survival time or disease-free interval. Our results indicate β-catenin is frequently expressed within the cytoplasm of neoplastic cells in canine OSA but contains no detectable mutations in exon 3, similar to human OSA.     

Rearrangement patterns of the canine TCRγ locus in a distinct group of T cell lymphomas

The T cell antigen receptor chains are assembled through a rearrangement process that combines variable (V), diversity (D) and joining (J) region genes. Recently, the entire canine T cell receptor γ (TRG) locus was described. It is arranged in 8 cassettes with up to 3 V genes, 2 J genes and 1 C gene each. However, no data is available beyond the level of sequence analysis. The objective of this study was to identify rearranged genes of the canine TRG locus through experimental analysis and to assess gene usage and patterns of rearrangement in a series of canine T cell lymphomas. Rearranged genes were identified through computational analysis of recombination signal sequences (RSSs), a gene's potential to generate a polyclonal smear, and through sequencing of clonal rearrangements in a series of T cell lymphomas. Out of a total of 32 Vγ and Jγ genes, 21 genes were found to rearrange, 8 genes were considered not rearranged and 3 genes were suspected to rearrange but their status could not be determined definitely. Rearrangements of the canine TRG locus were assessed in a group of canine T cell lymphomas as well as 3 neoplastic T cell lines. An average of 4.6 rearrangements per lymphoma was found suggesting that canine T cells routinely rearrange multiple cassettes per allele. The most commonly rearranged Vγ genes belonged to subgroups Vγ2, Vγ3, and Vγ7. Genes in cassettes 2 and 3 preferentially rearranged within their respective cassettes, while Vγ genes in cassette 7 rearranged to a Jγ gene in cassette 8. There was a strong preference for Vγ2 genes to rearrange to a 3' Jγ gene and for Vγ3 and Vγ7 genes to rearrange to a 5' Jγ gene. This rearrangement pattern coincided with the conservation of the spacer sequence between V and J gene subgroups rather than the topologic location of genes. These data show that highly divergent spacer sequences allow for equally efficient recombination and suggest that spacer sequences can mediate compatibility between V and J genes.     

A history of canine parvovirus in Australia: what can we learn?

Canine parvovirus (CPV) has been reported throughout the world since the late 1970s. Published information was reviewed to draw insights into the epidemiology, pathogenesis, diagnosis, treatment and outcomes of CPV disease in Australia and the role of scientific research on CPV occurrence, with key research discoveries and knowledge gaps identified. Australian researchers contributed substantially to early findings, including the first reported cases of parvoviral myocarditis, investigations into disease aetiopathogenesis, host and environmental risk factors and links between CPV and feline panleukopenia. Two of the world's first CPV serological surveys were conducted in Australia and a 1980 national veterinary survey of Australian and New Zealand dogs revealed 6824 suspected CPV cases and 1058 deaths. In 2010, an Australian national disease surveillance system was launched; 4940 CPV cases were reported between 2009 and 2014, although underreporting was likely. A 2017 study estimated national incidence to be 4.12 cases per 1000 dogs, and an annual case load of 20,110 based on 4219 CPV case reports in a survey of all Australian veterinary clinics, with a 23.5% response rate. CPV disease risk factors identified included socioeconomic disadvantage, geographical location (rural/remote), season (summer) and rainfall (recent rain and longer dry periods both increasing risk). Age <16 weeks was identified as a risk factor for vaccination failure. Important knowledge gaps exist regarding national canine and feline demographic and CPV case data, vaccination coverage and population immunity, CPV transmission between owned dogs and other carnivore populations in Australia and the most effective methods to control epizootics.     

Endothelial cells and angiogenesis in the horse in health and disease—A review

The cardiovascular system is the first functional organ in the embryo, and its blood vessels form a widespread conductive network within the organism. Blood vessels develop de novo, by the differentiation of endothelial progenitor cells (vasculogenesis) or by angiogenesis, which is the formation of new blood vessels from existing ones. This review presents an overview of the current knowledge on physiological and pathological angiogenesis in the horse including studies on equine endothelial cells. Principal study fields in equine angiogenesis research were identified: equine endothelial progenitor cells; equine endothelial cells and angiogenesis (heterogeneity, markers and assessment); endothelial regulatory molecules in equine angiogenesis; angiogenesis research in equine reproduction (ovary, uterus, placenta and conceptus, testis); angiogenesis research in pathological conditions (tumours, ocular pathologies, equine wound healing, musculoskeletal system and laminitis). The review also includes a table that summarizes in vitro studies on equine endothelial cells, either describing the isolation procedure or using previously isolated endothelial cells. A particular challenge of the review was that results published are fragmentary and sometimes even contradictory, raising more questions than they answer. In conclusion, angiogenesis is a major factor in several diseases frequently occurring in horses, but relatively few studies focus on angiogenesis in the horse. The challenge for the future is therefore to continue exploring new therapeutic angiogenesis strategies for horses to fill in the missing pieces of the puzzle.