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Rabbits are popular pets in the urban environment of Hong Kong, ranking third behind cats and dogs. Here we describe the frequency of neoplastic and non-neoplastic lesions in biopsies from pet rabbits submitted to the CityU Veterinary Diagnostic Laboratory between 2019 and 2022, comprising 247 tissue samples from 243 rabbits collected by veterinarians in 19 veterinary clinics. Among the 243 rabbits, there were 128 females (65 spayed), 114 males (54 castrated); sex information was not provided for 1 rabbit. The rabbit breeds included 45 Lionhead, 35 Dwarf, 14 Lop, 11 Dwarf Lop, 5 French Lop, 3 Angora, 2 Dutch, 2 Holland Lop, and 1 each of Netherland Dwarf, Velveteen, Mini Lop, and New Zealand White. The mean ages of rabbits with neoplastic and non-neoplastic lesions were 7.1 and 5.7 y, respectively. The most common neoplastic lesions were adenocarcinoma (26.4%), trichoblastoma (21.4%), sarcoma (9.4%), and thymoma (8.2%). The most common non-neoplastic lesion was uterine cystic endometrial hyperplasia (14.8%), followed by dermal abscess formation in the ventral abdomen or skin of the head (12.5%). Although a broad spectrum of other lesions was described, our findings in biopsies from pet rabbits in Hong Kong are consistent with those in other jurisdictions., Competing Interests: Declaration of conflicting interestThe authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: Polyacrylamide hydrogel (4% PAHG) is an inert viscoelastic supplement used to manage osteoarthritis in horses. Even with a prolonged clinical effect, horses may be administered multiple doses during their performance career. The effect of the serial 4% PAHG treatments is not known. The objectives of this study were to evaluate the clinical, histologic, and synovial fluid biomarker effects following serial administration of 4% PAHG in normal equine fetlock joints., Animals: 8 healthy horses., Methods: In a blinded, controlled in vivo study, horses received serial intra-articular injections of 4% PAHG (Noltrex Vet; Nucleus ProVets LLC) and contralateral 0.9% saline control on days 0, 45, 90, and 135. Treatment and control joints were randomly assigned. Synovial fluid was collected before administration of 4% PAHG or 0.9% saline on day 0 and at study completion for cellular and biomarker evaluation. Serial physical and lameness examinations were performed throughout the study. On day 240, gross examination and harvest of cartilage and synovial membrane for histology were completed., Results: There were no histologic changes in articular cartilage or synovial fluid biomarkers. The 4% PAHG was seen on the surface of the synovium in 5 of 8 treated joints 105 days after the last treatment. There are minimal effects following serial injections of 4% PAHG on normal joints in horses following administration at 0, 45, 90, and 135 days, with final evaluation on day 240., Clinical Relevance: Serial administration of intra-articular 4% PAHG in horses may provide long-term joint lubrication with no detrimental effects.

Septic arthritis is considered a medical emergency. Disease following bacterial colonization can lead to significant morbidity and mortality and requires costly treatment. Antimicrobial properties of regenerative therapies, including mesenchymal stromal cells and platelet products, have been researched extensively in human medicine. Although fewer studies have been conducted in veterinary species, they have shown promising results. The purpose of this study was to evaluate bacterial suppression by equine platelet lysate (EPL) and adipose-derived mesenchymal stromal cells (ASCs) in vitro . We hypothesized that both products would significantly inhibit the growth of Staphylococcus aureus and Escherichia coli . Pooled blood from 10 horses was used for production of EPL. Mesenchymal stromal cells were isolated from adipose tissue harvested from the gluteal region of 3 horses. The study evaluated 3 treatment groups: 10 × EPL, 1.6 million ASCs, and a control, using an incomplete unbalanced block design with repeated measurements. Optical density readings and colony-forming units/mL were calculated at 0, 3, 6, 9, 12, 18, and 24 hours. Decreased bacterial growth was seen at multiple time points for the S. aureus -ASC and S. aureus -EPL treatments, supporting our hypothesis. Increased bacterial growth was noticed in the E. coli -EPL group, with no difference in the E. coli -ASC treatment, which opposed our hypothesis. A clear conclusion of antimicrobial effects of EPL and ASCs cannot be made from this in vitro study. Although it appears that ASCs have a significant effect on decreasing the growth of S. aureus , further studies are needed to explore these effects, particularly in Gram-positive bacteria., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Ehrlichia ruminantium , a tick-borne rickettsial, causes heartwater in ruminants resulting from vascular damage. Severity of heartwater varies greatly in ruminant species and breeds, age of animals and for diverse geographic E . ruminantium strains. E. ruminantium and a tick vector, Amblyomma variegatum , originating from Africa, are well established in certain Caribbean islands two centuries ago. Besides the possibility of introduction of heartwater through African exotic animal importation, presence of the pathogen, and the tick vector in the Caribbean pose a high risk to ruminants in the USA and other western hemisphere countries. Scientific evidence supporting the heartwater threat to nonendemic regions, however, is lacking. We describe the first infection study in sheep reared in the USA with seven E. ruminantium strains. All infected sheep exhibited clinical signs characteristic of subacute to subclinical disease, which included labored breathing, depression, coughing, and nasal discharges. Gross and microscopic lesions consistent with heartwater disease including edema and hemorrhage were observed in several organs. Pathogen-specific IgG antibody response was detected in animals infected with all seven strains, while molecular analysis confirmed the pathogen presence only when infected with in vitro cultures. This is the first infection study demonstrating severe heartwater in sheep reared in North America.

Background: Percutaneous microwave ablation is clinically used for inoperable lung tumour treatment. Delivery of microwave ablation applicators to tumour sites within lung parenchyma under virtual bronchoscopy guidance may enable ablation with reduced risk of pneumothorax, providing a minimally invasive treatment of early-stage tumours, which are increasingly detected with computed tomography (CT) screening. The objective of this study was to integrate a custom microwave ablation platform, incorporating a flexible applicator, with a clinically established virtual bronchoscopy guidance system, and to assess technical feasibility for safely creating localised thermal ablations in porcine lungs in vivo ., Methods: Pre-ablation CTs of normal pigs were acquired to create a virtual model of the lungs, including airways and significant blood vessels. Virtual bronchoscopy-guided microwave ablation procedures were performed with 24-32 W power (at the applicator distal tip) delivered for 5-10 mins. A total of eight ablations were performed in three pigs. Post-treatment CT images were acquired to assess the extent of damage and ablation zones were further evaluated with viability stains and histopathologic analysis., Results: The flexible microwave applicators were delivered to ablation sites within lung parenchyma 5-24 mm from the airway wall via a tunnel created under virtual bronchoscopy guidance. No pneumothorax or significant airway bleeding was observed. The ablation short axis observed on gross pathology ranged 16.5-23.5 mm and 14-26 mm on CT imaging., Conclusion: We have demonstrated the technical feasibility for safely delivering microwave ablation in the lung parenchyma under virtual bronchoscopic guidance in an in vivo porcine lung model., Competing Interests: Conflict of interest: J. Sebek reports grant from the Czech Ministry of Education, Youth and Sports, during the conduct of the study. Conflict of interest: S. Kramer has nothing to disclose. Conflict of interest: R. Rocha has nothing to disclose. Conflict of interest: K-C. Yu has nothing to disclose. Conflict of interest: R. Bortel reports grants from the Czech Ministry of Education, Youth and Sports, during the conduct of the study. Conflict of interest: W.L. Beard has nothing to disclose. Conflict of interest: D.S. Biller has nothing to disclose. Conflict of interest: D.S. Hodgson has nothing to disclose. Conflict of interest: C.K. Ganta has nothing to disclose. Conflict of interest: H. Wibovo has nothing to disclose. Conflict of interest: J. Yee has nothing to disclose. Conflict of interest: R. Myers has nothing to disclose. Conflict of interest: S. Lam has nothing to disclose. Conflict of interest: P. Prakash reports grants from the National Institutes of Health during the conduct of the study; and grants from Hologic, Inc., and the National Institutes of Health, outside the submitted work. In addition, P. Prakash has a patent US 62/450,916 pending and within the past 12 months, in addition to the active grants listed above, has received grants from Neurent Medical, Ltd. and Broncus Medical, Inc., for projects unrelated to this work. These projects are now completed and no longer active., (Copyright ©ERS 2020.)

Ehrlichia chaffeensis , a tick-transmitted obligate intracellular rickettsial agent, causes human monocytic ehrlichiosis. In recent reports, we described substantial advances in developing random and targeted gene disruption methods to investigate the functions of E. chaffeensis genes. We reported earlier that the Himar1 transposon-based random mutagenesis is a valuable tool in defining E. chaffeensis genes critical for its persistent growth in vivo in reservoir and incidental hosts. The method also aided in extending studies focused on vaccine development and immunity. Here, we describe the generation and mapping of 55 new mutations. To define the critical nature of the bacterial genes, infection experiments were carried out in the canine host with pools of mutant organisms. Infection evaluation in the physiologically relevant host by molecular assays and by xenodiagnoses allowed the identification of many proteins critical for the pathogen's persistent in vivo growth. Genes encoding proteins involved in biotin biosynthesis, protein synthesis and fatty acid biosynthesis, DNA repair, electron transfer, and a component of a multidrug resistance (MDR) efflux pump were concluded to be essential for the pathogen's in vivo growth. Three known immunodominant membrane proteins, i.e., two 28-kDa outer membrane proteins (P28/OMP) and a 120-kDa surface protein, were also recognized as necessary for the pathogen's obligate intracellular life cycle. The discovery of many E. chaffeensis proteins crucial for its continuous in vivo growth will serve as a major resource for investigations aimed at defining pathogenesis and developing novel therapeutics for this and related pathogens of the rickettsial family Anaplasmataceae ., (Copyright © 2020 Wang et al.)

Purpose: To experimentally characterize a microwave (MW) ablation applicator designed to produce directional ablation zones., Materials and Methods: Using a 14-gauge, 2.45-GHz side-firing MW ablation applicator, 36 ex vivo bovine liver ablations were performed. Ablations were performed at 60 W, 80 W, and 100 W for 3, 5, and 10 minutes (n = 4 per combination). Ablation zone forward and backward depth and width were measured and directivity was calculated as the ratio of forward to backward depth. Thirteen in vivo ablations were performed in 2 domestic swine with the applicator either inserted into the liver (80 W, 5 min, n = 3; 100 W, 5 min, n = 3; 100 W, 10 min, n = 2) or placed on the surface of the liver with a nontarget tissue placed on the back side of the applicator (80 W, 5 min, n = 5). The animals were immediately euthanized after the procedure; the livers were harvested and sectioned perpendicular to the axis of the applicator. In vivo ablation zones were measured following viability staining and assessed on histopathology., Results: Mean ex vivo ablation forward depth was 8.3-15.5 mm. No backward heating was observed at 60 W, 3-5 minutes; directivity was 4.7-11.0 for the other power and time combinations. In vivo ablation forward depth was 10.3-11.5 mm, and directivity was 11.5-16.1. No visible or microscopic thermal damage to nontarget tissues in direct contact with the back side of the applicator was observed., Conclusions: The side-firing MW ablation applicator can create directional ablation zones in ex vivo and in vivo tissues., (Copyright © 2020 SIR. Published by Elsevier Inc. All rights reserved.)

Physical activity is associated with diminished risk of several cancers, and preclinical studies suggest exercise training may alter tumor cell growth in certain tissue(s) (e.g., adipose). From moderate-intensity exercise-trained rats versus sedentary controls, we hypothesized 1) there will be a decreased prostate cancer cell viability and migration in vitro and, within the prostate, a reduced 5α-reductase 2 (5αR2) and increased caspase-3 expression, and 2) that exercise training in tumor-bearing (TB) animals will demonstrate a reduced tumor cell viability in prostate-conditioned media. Serum and prostate were harvested from sedentary or exercise-trained (treadmill running, 10-11 weeks) immune-competent (Copenhagen; n = 20) and -deficient (Nude; n = 18) rats. AT-1 and PC-3 prostate cancer cells were grown in one or more of the following: serum-supplemented media (SSM), SSM from TB rats (SSM-TB), prostate-conditioned media (PCM) or PCM from TB rats (PCM-TB) for 24-96 h under normoxic (18.6% O 2 ) or hypoxic (5% O 2 ) conditions. Under normoxic condition, there was a decreased AT-1 cell viability in SSM and PCM from the exercise-trained (ET) immune-competent rats, but no difference in PC-3 cell viability in SSM and PCM from ET Nude rats versus the sedentary (SED) group, or in SSM-TB from ET-TB Nude rats versus the SED-TB group. However, there was a decreased PC-3 cell viability in the PCM-TB of the ET-TB group versus SED-TB group. PC-3 cell viability in all conditioned media types was not altered between groups with hypoxia. In the prostate, exercise training did not alter 5αR2 expression levels, but increased caspase-3 expression levels. In conclusion, prior exercise status reduced prostate cancer cell viability in the serum and prostate of trained rats but did not modify several other key prostate tumor cell growth characteristics (e.g., migration, cell cycle except in S phase of PC-3 cells in PCM-TB). Importantly, once the tumor was established, exercise training reduced tumor cell viability in the surrounding prostate, which may help explain the reduced severity of the disease in patients that exercise., Competing Interests: None.

Objective: To investigate the feasibility and efficacy of localized, subtotal, cortical-sparing microwave thermal ablation (MTA) as a potential curative management for primary aldosteronism. The study investigated with equal importance the selected ablation of small volumes of adrenal cortex while sparing adjacent cortex. Method: An in-vivo study was carried out in swine ( n  = 8) where MTA was applied under direct visualization, to the adrenal glands at 45 W or 70 W for 60 s, using a lateral, side-firing probe and a non-penetrative approach. Animals were survived for 48 h post-procedurally. Animals were investigated for markers of histological, immunohistochemical and biochemical evidence of adrenal function and adrenal damage by assessing samples drawn intra-operatively and at the time of euthanasia. Results: Selected MTA (70 W for 60 s) successfully ablated small adrenocortical volumes (∼0.8 cm 3 ) characterized by coagulative necrosis and abnormal expression of functional markers (CYP11B1 and CYP17). Non-ablated, adjacent cortex was not affected and preserved normal expression of functional markers, without increased expression of markers of heat damage (HSP-70 and HMGB-1). Limited adrenal medullary damage was demonstrated histologically, clinically and biochemically. Conclusion: MTA offers potential as an efficient methodology for delivering targeted subtotal cortical-sparing adrenal ablation. Image-guided targeted MTA may also represent a safe future modality for curative management of PA, in the setting of both unilateral and bilateral disease.

Ehrlichia chaffeensis is an obligate intracellular bacterium belonging to the order, Rickettsiales and is a frequent cause of severe and fatal tick-borne infection in people in North America. The reservoir host for E. chaffeensis is the white-tailed deer, while humans and dogs are regarded as common incidental hosts. In dogs, we and others have shown that E. chaffeensis establishes a chronic infection that persists for several weeks to months, while promoting the development of Th1 and Th17 cellular responses and pathogen-specific humoral immunity. We demonstrate here that vaccination with a live, attenuated clone of E. chaffeensis bearing a targeted mutation in the Ech_0230 gene neither promotes the development of long-lived cellular or humoral immunity, nor confers protection against secondary wild-type E. chaffeensis challenge. In dogs, a population of mature CD4 + CD8 + double-positive (DP) T cells exists in the periphery that shares similarities with the DP T cell populations that have been described in humans and swine. Little is known about the function of these cells, particularly in the context of infectious diseases. Here, we demonstrate that canine DP T cells expand significantly in response to E. chaffeensis infection. Using in vitro antigen recall assays, we further demonstrate that canine DP T cells undergo clonal expansion, produce IFNγ and IL-17, and upregulate expression of granzyme B and granulysin. Together, our results demonstrate that DP T cells accumulate in the host during E. chaffeensis infection, and suggest that alternative lymphocyte populations may participate in the immune response to tick-borne infections in the incidental host.

The rostral ventrolateral medulla (RVLM) is an area of the brain stem that contains diverse neural substrates that are involved in systems critical for physiological function. There is evidence that aging affects some neural substrates within the RVLM, although age-related changes in RVLM molecular mechanisms are not well established. The goal of the present study was to characterize the transcriptomic profile of the aging RVLM and to test the hypothesis that aging is associated with altered gene expression in the RVLM, with an emphasis on immune system associated gene transcripts. RVLM tissue punches from young, middle-aged, and aged F344 rats were analyzed with Agilent's whole rat genome microarray. The RVLM gene expression profile varied with age, and an association between chronological age and specific RVLM gene expression patterns was observed [ P < 0.05, false discovery rate (FDR) < 0.3]. Functional analysis of RVLM microarray data via gene ontology profiling and pathway analysis identified upregulation of genes associated with immune- and stress-related responses and downregulation of genes associated with lipid biosynthesis and neurotransmission in aged compared with middle-aged and young rats. Differentially expressed genes associated with the complement system and microglial cells were further validated by quantitative PCR with separate RVLM samples ( P < 0.05, FDR < 0.1). The present results have identified age-related changes in the transcriptomic profile of the RVLM, modifications that may provide the molecular backdrop for understanding age-dependent changes in physiological regulation.

Dogs acquire infections with the Anaplasmataceae family pathogens, E. canis, E. chaffeensis, E. ewingii, A. platys and A. phagocytophilum mostly during summer months when ticks are actively feeding on animals. These pathogens are also identified as causing diseases in people. Despite the long history of tick-borne diseases in dogs, much remains to be defined pertaining to the clinical and pathological outcomes of infections with these pathogens. In the current study, we performed experimental infections in dogs with E. canis, E. chaffeensis, A. platys and A. phagocytophilum. Animals were monitored for 42 days to evaluate infection-specific clinical, hematological and pathological differences. All four pathogens caused systemic persistent infections detectible throughout the 6 weeks of infection assessment. Fever was frequently detected in animals infected with E. canis, E. chaffeensis, and A. platys, but not in dogs infected with A. phagocytophilum. Hematological differences were evident in all four infected groups, although significant overlap existed between the groups. A marked reduction in packed cell volume that correlated with reduced erythrocytes and hemoglobin was observed only in E. canis infected animals. A decline in platelet numbers was common with E. canis, A. platys and A. phagocytophilum infections. Histopathological lesions in lung, liver and spleen were observed in all four groups of infected dogs; infection with E. canis had the highest pathological scores, followed by E. chaffeensis, then A. platys and A. phagocytophilum. All four pathogens induced IgG responses starting on day 7 post infection, which was predominantly comprised of IgG2 subclass antibodies. This is the first detailed investigation comparing the infection progression and host responses in dogs after inoculation with four pathogens belonging to the Anaplasmataceae family. The study revealed a significant overlap in clinical, hematological and pathological changes resulting from the infections.