Veterinary Clinical Sciences - Research Publications
Now showing items 1-12 of 259
Synergistic functions of E2F7 and E2F8 are critical to suppress stress-induced skin cancer.
(Springer Science and Business Media LLC, 2017-02-09)
E2F transcription factors are important regulators of the cell cycle, and unrestrained activation of E2F-dependent transcription is considered to be an important driver of tumor formation and progression. Although highly expressed in normal skin and skin cancer, the role of the atypical E2Fs, E2F7 and E2F8, in keratinocyte homeostasis, regeneration and tumorigenesis is unknown. Surprisingly, keratinocyte-specific deletion of E2F7 and E2F8 in mice did not interfere with skin development and wound healing. However, the rate for successful isolation and establishment of E2f7/8-deficient primary keratinocyte cultures was much higher than for wild-type keratinocytes. Moreover, E2f7/8-deficient primary keratinocytes proliferate more efficiently under stress conditions, such as low/high confluence or DNA damage. Application of in vivo stress using the DMBA/TPA skin carcinogenesis protocol revealed that combined inactivation of E2f7/8 enhanced tumorigenesis and accelerated malignant progression. Loss of atypical E2Fs resulted in increased expression of E2F target genes, including E2f1. Additional loss of E2f1 did not rescue, but worsened skin tumorigenesis. We show that loss of E2F7/8 triggers apoptosis via induction of E2F1 in response to stress, indicating that the tumor-promoting effect of E2F7/8 inactivation can be partially compensated via E2F1-dependent apoptosis. Importantly, E2F7/8 repressed a large set of E2F target genes that are highly expressed in human patients with skin cancer. Together, our studies demonstrate that atypical E2Fs act as tumor suppressors, most likely via transcriptional repression of cell cycle genes in response to stress.
Atypical E2Fs inhibit tumor angiogenesis.
(Springer Science and Business Media LLC, 2018-01-11)
Atypical E2F transcription factors (E2F7 and E2F8) function as key regulators of cell cycle progression and their inactivation leads to spontaneous cancer formation in mice. However, the mechanism of the tumor suppressor functions of E2F7/8 remain obscure. In this study we discovered that atypical E2Fs control tumor angiogenesis, one of the hallmarks of cancer. We genetically inactivated atypical E2Fs in epithelial and mesenchymal neoplasm and analyzed blood vessel formation in three different animal models of cancer. Tumor formation was either induced by application of 7,12-Dimethylbenz(a)anthracene/12-O-Tetradecanoylphorbol-13-acetate or by Myc/Ras overexpression. To our surprise, atypical E2Fs suppressed tumor angiogenesis in all three cancer models, which is in a sharp contrast to previous findings showing that atypical E2Fs promote angiogenesis during fetal development in mice and zebrafish. Real-time imaging in zebrafish displayed that fluorescent-labeled blood vessels showed enhanced intratumoral branching in xenografted E2f7/8-deficient neoplasms compared with E2f7/8-proficient neoplasms. DLL4 expression, a key negative inhibitor of vascular branching, was decreased in E2f7/8-deficient neoplastic cells, indicating that E2F7/8 might inhibit intratumoral vessel branching via induction of DLL4.
Evaluation of haemoparasite and Sarcocystis infections in Australian wild deer
Wild animals are natural reservoir hosts for a variety of pathogens that can be transmitted to other wildlife, livestock, other domestic animals, and humans. Wild deer (family Cervidae) in Europe, Asia, and North and South America have been reported to be infected with gastrointestinal and vector-borne parasites. In Australia, wild deer populations have expanded considerably in recent years, yet there is little information regarding which pathogens are present and whether these pathogens pose biosecurity threats to humans, wildlife, livestock, or other domestic animals. To address this knowledge gap, PCR-based screening for five parasitic genera was conducted in blood samples (n = 243) sourced from chital deer (Axis axis), fallow deer (Dama dama), rusa deer (Rusa timorensis) and sambar deer (Rusa unicolor) sampled in eastern Australia. These blood samples were tested for the presence of DNA from Plasmodium spp., Trypanosoma spp., Babesia spp., Theileria spp. and Sarcocystis spp. Further, the presence of antibodies against Babesia bovis was investigated in serum samples (n = 105) by immunofluorescence. In this study, neither parasite DNA nor antibodies were detected for any of the five genera investigated. These results indicate that wild deer are not currently host reservoirs for Plasmodium, Trypanosoma, Babesia, Theileria or Sarcocystis parasites in eastern Australia. We conclude that in eastern Australia, wild deer do not currently play a significant role in the transmission of these parasites. This survey represents the first large-scale molecular study of its type in Australian wild deer and provides important baseline information about the parasitic infection status of these animals. The expanding populations of wild deer throughout Australia warrant similar surveys in other parts of the country and surveillance efforts to continually assess the level of threat wild deer could pose to humans, wildlife, livestock and other domestic animals.
Longitudinal Survey of Fecal Microbiota in Healthy Dogs Administered a Commercial Probiotic
(FRONTIERS MEDIA SA, 2021-06-21)
The aim of this longitudinal microbiome study was to investigate the effects of a commercially available veterinary synbiotic product (Blackmore's® Paw DigestiCare 60™) on the fecal microbiome of healthy dogs using 16S rRNA gene microbial profiling. Fifteen healthy, privately-owned dogs participated in a 2-week trial administration of the product. Fecal samples were collected at different time points, including baseline (prior to treatment), during administration and after discontinuation of product. Large intra- and inter-individual variation was observed throughout the study, but microbiome composition at higher phylogenetic levels, alpha and beta diversity were not significantly altered after 2 weeks of probiotic administration, suggesting an absence of probiotic impact on microbial diversity. Administration of the synbiotic preparation did, however, result in transient increases in probiotic species from Enterococacceae and Streptococacceae families as well as an increase in Fusobacteria; with the fecal microbiota partially reverting to its baseline state 3-weeks after cessation of probiotic administration.
Sensory and Physical Characteristics of M. biceps femoris from Older Cows Using Ginger Powder (Zingibain) and Sous Vide Cooking
This study aimed to evaluate the sensory and physical characteristics of zingibain-injected meat combined with sous vide cooking. M. biceps femoris (BF; n = 12) acquired from 6-7 year old Angus cows were cooked using the sous vide method at 65 °C, for 8 h or 12 h, either with ginger powder (GP) injected in a 2 g/L solution in water (treatment) or un-injected (control). The sensory attributes included flavour, juiciness, tenderness, and physicochemical characteristics were Warner-Bratzler shear (WBSF), hardness, total water content (TWC), cooking loss (CL) and collagen content. A significant improvement in tenderness with injection treatment and cooking time was observed, as evaluated through trained sensory panellists, and reduced WBSF and hardness (p < 0.05 for all). The flavour of the meat was not affected by injection treatment or cooking time (p > 0.05), but juiciness and TWC were reduced with longer cooking times (p < 0.01 for both). Soluble collagen increased with injection treatment and cooking time (both p < 0.05). Moderate to high correlations were found between sensory and physical measurements for tenderness and juiciness. The longer cooking time (12 h) with GP injection treatment caused over tenderization of the meat. The soft texture associated with over-tenderization may be suitable for some specialised consumer markets, for instance, the elderly population with chewing difficulties. Improving the eating quality of low-quality meat from old animals through sous vide cooking and the use of ginger proteases may increase the acceptability of lower value beef, potentially enhancing the commercial value of carcasses typically produced in the beef industry.
Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats.
(Springer Science and Business Media LLC, 2021-05-14)
In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development's (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security.
Molecular Epidemiology and Characterization of Picobirnavirus in Wild Deer and Cattle from Australia: Evidence of Genogroup I and II in the Upper Respiratory Tract
Picobirnaviruses (PBVs) have been detected in several species of animals worldwide; however, data pertaining to their presence in Australian wild and domestic animals are limited. Although PBVs are mostly found in faecal samples, their detection in blood and respiratory tract samples raises questions concerning their tropism and pathogenicity. We report here PBV detection in wild deer and cattle from southeastern Australia. Through metagenomics, the presence of PBV genogroups I (GI) and II (GII) were detected in deer serum and plasma. Molecular epidemiology studies targeting the partial RNA-dependent RNA polymerase gene were performed in a wide range of specimens (serum, faeces, spleen, lung, nasal swabs, and trachea) collected from wild deer and cattle, with PCR amplification obtained in all specimen types except lung and spleen. Our results reveal the predominance of GI and concomitant detection of both genogroups in wild deer and cattle. In concordance with other studies, the detected GI sequences displayed high genetic diversity, however in contrast, GII sequences clustered into three distinct clades. Detection of both genogroups in the upper respiratory tract (trachea and nasal swab) of deer in the present study gives more evidence about the respiratory tract tropism of PBV. Although much remains unknown about the epidemiology and tropism of PBVs, our study suggests a wide distribution of these viruses in southeastern Australia.
ACVIM consensus statement on pancreatitis in cats
BACKGROUND: Pancreatitis in cats, although commonly diagnosed, still presents many diagnostic and management challenges. OBJECTIVE: To summarize the current literature as it relates to etiology, pathogenesis, diagnosis, and management of pancreatitis in cats and to arrive at clinically relevant suggestions for veterinary clinicians that are based on evidence, and where such evidence is lacking, based on consensus of experts in the field. ANIMALS: None. METHODS: A panel of 8 experts in the field (5 internists, 1 radiologist, 1 clinical pathologist, and 1 anatomic pathologist), with support from a librarian, was formed to assess and summarize evidence in the peer reviewed literature and complement it with consensus clinical recommendations. RESULTS: There was little literature on the etiology and pathogenesis of spontaneous pancreatitis in cats, but there was much in the literature about the disease in humans, along with some experimental evidence in cats and nonfeline species. Most evidence was in the area of diagnosis of pancreatitis in cats, which was summarized carefully. In contrast, there was little evidence on the management of pancreatitis in cats. CONCLUSIONS AND CLINICAL IMPORTANCE: Pancreatitis is amenable to antemortem diagnosis by integrating all clinical and diagnostic information available, and recognizing that acute pancreatitis is far easier to diagnose than chronic pancreatitis. Although both forms of pancreatitis can be managed successfully in many cats, management measures are far less clearly defined for chronic pancreatitis.
Unique cytologic and histologic features of a suspected cutaneous xanthoma in a dog
A 4-year-old spayed female American Staffordshire Terrier presented to the U-Vet Animal Hospital, Werribee, Australia, with a cutaneous mass that had been slowly growing over 12 months. Cytologic evaluation showed cohesive to individualized, vacuolated spindled cells often arranged in a perivascular pattern. The mass was completely excised, and the histopathologic examination demonstrated sheets of vacuolated spindled to round cells expanding the full thickness of the dermis. The cells demonstrated both Iba1 and CD18 antibody binding, leading to an initial interpretation of histiocytic sarcoma. Given the discordance with the clinical presentation, further immunohistochemistry (IHC) was performed. The cells demonstrated strong CD204 antibody binding and did not bind E-cadherin antibody, consistent with a dermal macrophage origin. Ki-67 antibody binding was regionally variable from <5% to 25%, with more regions that had low Ki-67 expression. A fasted serum biochemistry panel revealed hypertriglyceridemia and persistent hypercholesterolemia. Based on clinical, microscopic, biochemical, and IHC results, the final interpretation was an indolent dermal histiocytic proliferation of macrophage origin, with a preference for cutaneous xanthoma or reactive dermal fibrohistiocytoma.
Breed is associated with the ABCB1-1 Delta mutation in Australian dogs
OBJECTIVE: The ABCB1 gene encodes P-glycoprotein (P-gp), a cellular membrane pump. One functional mutation that leads to expression of a less functional form of P-gp, ABCB1-1Δ, has been described in dogs. Individuals with this mutation can have severe adverse reactions to common veterinary pharmaceuticals that are known substrates of this pump. We investigated the detection of this mutation in samples submitted to two Australian diagnostic laboratories. METHODS: A total of 4842 dogs across 27 breeds were tested for the ABCB1-1Δ mutation from buccal swabs or EDTA blood using standard PCR, multiplex PCR, or genotyping chip. Statistical analysis was applied to determine the proportions and odds ratios of the ABCB1-1Δ mutation in herding breeds compared with non-herding breeds. RESULTS: The ABCB1-1Δ mutation was detected in nine breeds. The most commonly affected breeds were collies, Australian shepherds, white Swiss shepherds, and Shetland sheepdogs. Of 32 dogs in 18 non-herding breeds tested, one cocker spaniel and one labradoodle were positive for the mutation, both heterozygous. CONCLUSION: The most frequently affected breeds for ABCB1-1Δ mutation are the collie, Australian shepherd, white Swiss shepherd and Shetland sheepdog. As the mutation is associated with an increased incidence of adverse reactions to commonly used pharmaceuticals, veterinarians need to be aware of the breeds at most risk of carrying this mutation and consider testing these individuals prior to administering these medications.