Multifocal discrete osteolysis in a horse with silicate associated osteoporosis.

Silicate associated osteoporosis (SAO) was diagnosed post mortem in an adult horse with the shortest documented exposure to cytotoxic silicates of 2 years. The horse was evaluated for a 6-months history of progressive back tenderness and acute onset of lameness. The horse had a marked (4/5) [American Association of Equine Practitioners scale] left forelimb lameness, moderate (2/5) hindlimb ataxia and weakness, and cervical pain upon palpation. Physical examination did not reveal clinical skeletal deformities or respiratory compromise. Radiographs revealed widespread, discrete, sharply delineated, osteolytic lesions in the skull, vertebral column, ribs, scapulae and middle phalanx (P2) of the left forelimb and a diffuse bronchointerstitial lung pattern. The presumptive clinical diagnosis was widespread, metastatic osteolytic neoplasia. Due to the poor quality of life and grave prognosis, the horse was humanely euthanised. Post mortem examination revealed pulmonary silicosis in the lungs and hilar lymph nodes and osteolytic lesions with numerous, large osteoclasts and disorganised bone remodeling both consistent with SAO. SAO should be included as a differential diagnosis for horses with widespread, multifocal, discrete osteolysis and history of exposure to endemic regions with possible cytotoxic silicate inhalation. Exposure time of 2 years is potentially sufficient to develop SAO.

Evaluation of P16 expression in canine appendicular osteosarcoma.

BACKGROUND: Osteosarcoma (OSA) is a common malignant bone tumor of large breed dogs that occurs at predictable anatomic sites. At the time of initial diagnosis, most affected dogs have occult pulmonary metastases. Even with aggressive surgical treatment combined with chemotherapy, the majority of dogs diagnosed with OSA live less than 1 year from the time of diagnosis. The ability to identify canine OSA cases most responsive to treatment is needed. In humans, OSA is also an aggressive tumor that is histologically and molecularly similar to canine OSA. The expression of the tumor suppressor gene product P16 by human OSA tissue has been linked to a favorable response to chemotherapy. RESULTS: We identified an antibody that binds canine P16 and developed a canine OSA tissue microarray in order to test the hypothesis that P16 expression by canine OSA tissue is predictive of clinical outcome following amputation and chemotherapy. Although statistical significance was not reached, a trend was identified between the lack of canine OSA P16 expression and a shorter disease free interval. CONCLUSIONS: The identification of a molecular marker for canine OSA is an important goal and the results reported here justify a larger study.

Nasal Cavity Masses Resembling Chondro-osseous Respiratory Epithelial Adenomatoid Hamartomas in 3 Dogs.

Chondro-osseous respiratory epithelial adenomatoid hamartomas (COREAHs) are rare tumors in the nasal cavity of people, which have not been described in other species. COREAHs in people are minimally invasive and rarely recur following excision. Histologically, these tumors are composed of disorganized, mature, nasal turbinate tissue that is organized into polypoid growths. These growths are lined by respiratory epithelium, contain glandular elements, and are organized around central cores of chondro-osseous matrix. This report describes 3 cases of dogs with nasal tumors that have histomorphology similar to that of COREAH in people. The tumors were all identified within the nasal cavity and were associated with regional bony lysis of the turbinates and surrounding skull bones, a feature that has not been reported in COREAH in people. There was no evidence of metastasis or extension beyond the nasal cavity in any of the 3 cases.

Chytridiomycosis in dwarf African frogs Hymenochirus curtipes.

Chytridiomycosis, resulting from an infection with the fungal agent Batrachochytrium dendrobatidis (Bd), has resulted in widespread population declines in both wild and captive amphibians. The dwarf African frog (DAF) Hymenochirus curtipes is native to central Africa and is commonly sold throughout North America as an aquarium pet species. Here we document fatal chytridiomycosis resulting from cutaneous Bd infections in DAF purchased directly from a pet store and from a historical lethal epizootic occurring at an aquaculture facility in central California, USA, more than 25 yr ago. Histological lesions and PCR-amplified sequence data were consistent with the etiology of Bd. The potential epidemiological relevance of this infection in DAF is discussed.

Common and emerging infectious diseases in the animal shelter.

The beneficial role that animal shelters play is unquestionable. An estimated 3 to 4 million animals are cared for or placed in homes each year, and most shelters promote public health and support responsible pet ownership. It is, nonetheless, inevitable that shelters are prime examples of anthropogenic biological instability: even well-run shelters often house transient, displaced, and mixed populations of animals. Many of these animals have received minimal to no prior health care, and some have a history of scavenging or predation to survive. Overcrowding and poor shelter conditions further magnify these inherent risks to create individual, intraspecies, and interspecies stress and provide an environment conducive to exposure to numerous potentially collaborative pathogens. All of these factors can contribute to the evolution and emergence of new pathogens or to alterations in virulence of endemic pathogens. While it is not possible to effectively anticipate the timing or the pathogen type in emergence events, their sites of origin are less enigmatic, and pathologists and diagnosticians who work with sheltered animal populations have recognized several such events in the past decade. This article first considers the contribution of the shelter environment to canine and feline disease. This is followed by summaries of recent research on the pathogenesis of common shelter pathogens, as well as research that has led to the discovery of novel or emerging diseases and the methods that are used for their diagnosis and discovery. For the infectious agents that commonly affect sheltered dogs and cats, including canine distemper virus, canine influenza virus, Streptococcus spp, parvoviruses, feline herpesvirus, feline caliciviruses, and feline infectious peritonitis virus, we present familiar as well as newly recognized lesions associated with infection. Preliminary studies on recently discovered viruses like canine circovirus, canine bocavirus, and feline norovirus indicate that these pathogens can cause or contribute to canine and feline disease.

Pharmacokinetics and pharmacodynamics of suberoylanilide hydroxamic acid in cats.

Suberoylanilide hydroxamic acid (SAHA), or vorinostat, is a histone deacetylase inhibitor approved for use as chemotherapy for lymphoma in humans. The goal of this study was to establish pharmacological parameters of SAHA in cats. Our interest in treating cats with SAHA is twofold: as an anticancer chemotherapeutic and as antilatency therapy for feline retroviral infections. Relying solely on data from studies in other animals would be inappropriate as SAHA is partially metabolized by glucuronidation, which is absent in feline metabolism. SAHA was administered to cats intravenously (2 mg/kg) or orally (250 mg/m², ~17 mg/kg) in a cross-over study design. Clinically, SAHA was well tolerated at these dosages as no abnormalities were noted following administration. The pharmacokinetics of SAHA in cats was found to be similar to that of dogs, but the overall serum drug exposure was much less than that of humans at an equivalent dose. The pharmacodynamic effect of an increase in acetylated histone proteins in blood was detected after both routes of administration. An increased oral dose of 60 mg SAHA/kg administered to one animal resulted in a surprisingly modest increase in peak drug concentration, suggesting possible saturation of absorption kinetics. This study provides a foundation for future studies of the clinical efficacy of SAHA in treating feline disease.

Sex differences in blood flow restricted isotonic knee extensions to fatigue.

AIM: It has been shown that females have greater muscular endurance than males and that this advantage is eliminated when blood flow is restricted. It is unknown if sex differences in dynamic endurance exist during low-load blood flow restricted (BFR) resistance exercise. The purpose of this study was to investigate sex differences in quadriceps femoris fatigability during isotonic knee extension exercise coupled with a blood flow restriction. METHODS: Ten males and ten females completed three sets of low-load isotonic knee extension exercises (20% of peak torque) to volitional failure under two conditions: blood flow restricted (BFR) and non-restricted free flow (FF). The number of repetitions, exercise volume, post-exercise strength loss and surface electromyography (EMG) were measured. RESULTS: Females performed more repetitions than males in the FF (252±37 vs. 112±17 repetitions; P<0.01) and BFR conditions (165±29 vs. 79±8 repetitions; P<0.01). Both sexes performed ~30% fewer repetitions during the BFR condition. MVC torque decreased approximately 37% following both conditions (P<0.01) and EMG activity increased (P<0.05) during the exercise bouts. CONCLUSION: Similar fatigue characteristics were evident in FF and BFR conditions for both sexes, and females demonstrated greater endurance, as determined by the number of repetitions completed, in both conditions. It may be beneficial to increase the relative exercise load for females in order to decrease the time under BFR.

Immunopathogenesis of canine chronic ulcerative stomatitis.

Canine Chronic Ulcerative Stomatitis is a spontaneously occurring inflammatory disease of the oral mucosa. An immune-mediated pathogenesis is suspected though not yet proven. We have recently reported on the clinical and histologic features, and identification of select leukocyte cell populations within the lesion. A clinical and histologic similarity to oral lichen planus of people was proposed. In the present study, these initial observations are extended by examining lesions from 24 dogs with clinical evidence of chronic ulcerative stomatitis. Because dogs with chronic ulcerative stomatitis often have concurrent periodontal disease, we wondered if dental plaque/biofilm may be a common instigator of inflammation in both lesions. We hypothesized that dogs with chronic ulcerative stomatitis would exhibit a spectrum of pathologic changes and phenotype of infiltrating leukocytes that would inform lesion pathogenesis and that these changes would differ from inflammatory phenotypes in periodontitis. Previously we identified chronic ulcerative stomatitis lesions to be rich in FoxP3+ and IL17+ cells. As such, we suspect that these leukocytes play an important role in lesion pathogenesis. The current study confirms the presence of moderate to large numbers of FoxP3+ T cells and IL17+ cells in all ulcerative stomatitis lesions using confocal immunofluorescence. Interestingly, the majority of IL17+ cells were determined to be non-T cells and IL17+ cell frequencies were negatively correlated with severity on the clinical scoring system. Three histologic subtypes of ulcerative stomatitis were determined; lichenoid, deep stomatitis and granulomatous. Periodontitis lesions, like stomatitis lesions, were B cell and plasma cell rich, but otherwise differed from the stomatitis lesions. Direct immunofluorescence results did not support an autoantibody-mediated autoimmune disease process. This investigation contributes to the body of literature regarding leukocyte involvement in canine idiopathic inflammatory disease pathogenesis.

The nucleoside analog GS-441524 strongly inhibits feline infectious peritonitis (FIP) virus in tissue culture and experimental cat infection studies.

Feline infectious peritonitis (FIP) is a common and highly lethal coronavirus disease of domestic cats. Recent studies of diseases caused by several RNA viruses in people and other species indicate that antiviral therapy may be effective against FIP in cats. The small molecule nucleoside analog GS-441524 is a molecular precursor to a pharmacologically active nucleoside triphosphate molecule. These analogs act as an alternative substrate and RNA-chain terminator of viral RNA dependent RNA polymerase. We determined that GS-441524 was non-toxic in feline cells at concentrations as high as 100 uM and effectively inhibited FIPV replication in cultured CRFK cells and in naturally infected feline peritoneal macrophages at concentrations as low as 1 uM. We determined the pharmacokinetics of GS-441524 in cats in vivo and established a dosage that would sustain effective blood levels for 24 h. In an experimental FIPV infection of cats, GS-441524 treatment caused a rapid reversal of disease signs and return to normality with as little as two weeks of treatment in 10/10 cats and with no apparent toxicity.

Peripheral and central immune cell reservoirs in tissues from asymptomatic cats chronically infected with feline immunodeficiency virus.

Feline immunodeficiency virus (FIV) infection in cats results in life-long viral persistence and progressive immunopathology. We have previously described a cohort of experimentally infected cats demonstrating a progressive decline of peripheral blood CD4+ T-cell over six years in the face of apparent peripheral viral latency. More recently we reported findings from this same cohort that revealed popliteal lymph node tissue as sites for ongoing viral replication suggesting that tissue reservoirs are important in FIV immunopathogenesis during the late asymptomatic phase of infection. Results reported herein characterize important tissue reservoirs of active viral replication during the late asymptomatic phase by examining biopsied specimens of spleen, mesenteric lymph node (MLN), and intestine from FIV-infected and uninfected control cats. Peripheral blood collected coincident with harvest of tissues demonstrated severe CD4+ T-cell depletion, undetectable plasma viral gag RNA and rarely detectable peripheral blood mononuclear cell (PBMC)-associated viral RNA (vRNA) by real-time PCR. However, vRNA was detectable in all three tissue sites from three of four FIV-infected cats despite the absence of detectable vRNA in plasma. A novel in situ hybridization assay identified B cell lymphoid follicular domains as microanatomical foci of ongoing FIV replication. Additionally, we demonstrated that CD4+ leukocyte depletion in tissues, and CD4+ and CD21+ leukocytes as important cellular reservoirs of ongoing replication. These findings revealed that tissue reservoirs support foci of ongoing viral replication, in spite of highly restricted viral replication in blood. Lentiviral eradication strategies will need address tissue viral reservoirs.

Viral Reservoirs in Lymph Nodes of FIV-Infected Progressor and Long-Term Non-Progressor Cats during the Asymptomatic Phase.

BACKGROUND: Examination of a cohort of cats experimentally infected with feline immunodeficiency virus (FIV) for 5.75 years revealed detectable proviral DNA in peripheral blood mononuclear cells (PBMCs) harvested during the asymptomatic phase, undetectable plasma viral RNA (FIV gag), and rarely detectable cell-associated viral RNA. Despite apparent viral latency in peripheral CD4+ T cells, circulating CD4+ T cell numbers progressively declined in progressor animals. The aim of this study was to explore this dichotomy of peripheral blood viral latency in the face of progressive immunopathology. The viral replication status, cellular immunophenotypes, and histopathologic features were compared between popliteal lymph nodes (PLNs) and peripheral blood. Also, we identified and further characterized one of the FIV-infected cats identified as a long-term non-progressor (LTNP). RESULTS: PLN-derived leukocytes from FIV-infected cats during the chronic asymptomatic phase demonstrated active viral gag transcription and FIV protein translation as determined by real-time RT-PCR, Western blot and in situ immunohistochemistry, whereas viral RNA in blood leukocytes was either undetectable or intermittently detectable and viral protein was not detected. Active transcription of viral RNA was detectable in PLN-derived CD4+ and CD21+ leukocytes. Replication competent provirus was reactivated ex vivo from PLN-derived leukocytes from three of four FIV-infected cats. Progressor cats showed a persistent and dramatically decreased proportion and absolute count of CD4+ T cells in blood, and a decreased proportion of CD4+ T cells in PLNs. A single long-term non-progressor (LTNP) cat persistently demonstrated an absolute peripheral blood CD4+ T cell count indistinguishable from uninfected animals, a lower proviral load in unfractionated blood and PLN leukocytes, and very low amounts of viral RNA in the PLN. CONCLUSION: Collectively our data indicates that PLNs harbor important reservoirs of ongoing viral replication during the asymptomatic phase of infection, in spite of undetectable viral activity in peripheral blood. A thorough understanding of tissue-based lentiviral reservoirs is fundamental to medical interventions to eliminate virus or prolong the asymptomatic phase of FIV infection.

Cartilage immunoprivilege depends on donor source and lesion location.

The ability to repair damaged cartilage is a major goal of musculoskeletal tissue engineering. Allogeneic (same species, different individual) or xenogeneic (different species) sources can provide an attractive source of chondrocytes for cartilage tissue engineering, since autologous (same individual) cells are scarce. Immune rejection of non-autologous hyaline articular cartilage has seldom been considered due to the popular notion of "cartilage immunoprivilege". The objective of this study was to determine the suitability of allogeneic and xenogeneic engineered neocartilage tissue for cartilage repair. To address this, scaffold-free tissue engineered articular cartilage of syngeneic (same genetic background), allogeneic, and xenogeneic origin were implanted into two different locations of the rabbit knee (n=3 per group/location). Xenogeneic engineered cartilage and control xenogeneic chondral explants provoked profound innate inflammatory and adaptive cellular responses, regardless of transplant location. Cytological quantification of immune cells showed that, while allogeneic neocartilage elicited an immune response in the patella, negligible responses were observed when implanted into the trochlea; instead the responses were comparable to microfracture-treated empty defect controls. Allogeneic neocartilage survived within the trochlea implant site and demonstrated graft integration into the underlying bone. In conclusion, the knee joint cartilage does not represent an immune privileged site, strongly rejecting xenogeneic but not allogeneic chondrocytes in a location-dependent fashion. This difference in location-dependent survival of allogeneic tissue may be associated with proximity to the synovium. STATEMENT OF SIGNIFICANCE: Through a series of in vivo studies this research demonstrates that articular cartilage is not fully immunoprivileged. In addition, we now show that anatomical location of the defect, even within the same joint compartment, strongly influences the degree of the resultant immune response. This is one of the first investigations to show that (1) immune tolerance to allogeneic tissue engineered cartilage and (2) subsequent implant survival are dependent on the implant location and proximity to the synovium.

Effect of immunosuppressive drug regime on cardiovascular risk profile following kidney transplantation.

We have previously studied cardiovascular risk markers apolipoprotein (a) (apo(a)) and plasma fibrinogen in 146 control, 60 haemodialysis (HD), 53 continuous ambulatory peritoneal dialysis (CAPD) and 66 renal transplant subjects. Fibrinogen concentration was higher in all 3 renal replacement groups compared to controls. Apo(a) was higher in the CAPD group only. We have now restudied those dialysis patients (24 HD, 16 CAPD) who have since undergone transplantation. Fibrinogen concentration remained elevated in CAPD patients (mean (SE) 3.9 (0.17) vs. 3.77 (0.20) grams/l) and increased in HD patients (2.88 (0.16) vs. 3.72 (0.13) grams/l, P < 0.0001). Apo(a) fell in both groups (CAPD, geometric mean 287 vs. 151 U/l, P = 0.008; HD, 230 vs. 179 U/l, P = 0.013). Fibrinogen concentration was higher in the recent group compared to the original group (3.74 (0.11) vs. 3.19 (0.12) grams/l, P = 0.001). None of the 66 original patients received cyclosporin (cyA) compared to 35 of the 40 in the present study. In this recent group, patients maintained on prednisolone and azathioprine alone had significantly lower fibrinogen levels than those receiving cyA. Furthermore, the fall in apo(a) was smaller (31% vs. 74%) and the increase in apolipoprotein B (apo B) greater (0.55 (0.15) vs. 0.18 (0.05) grams/l, P = 0.014) in cyA-treated patients. CyA may have an adverse effect on cardiovascular risk profile in renal transplant recipients.

Increased serum apolipoprotein(a) in patients with chronic renal failure treated with continuous ambulatory peritoneal dialysis.

Patients with end-stage renal failure (ESRF) on renal replacement therapy are at significantly increased risk of cardiovascular disease. To determine whether altered concentrations of apolipoprotein(a) (apo(a)), the plasminogen-like protein moiety of the atherogenic particle lipoprotein(a), contributed to this increased risk, apo(a) concentrations were measured in 48 non-diabetic patients with ESRF treated by continuous ambulatory peritoneal dialysis (CAPD) therapy and compared with 65 controls. Apo(a) concentration was increased in CAPD patients compared to controls (geometric mean 419 units/l versus 137 units/l; ratio of means 3.06 (95% CI 1.95-4.80). We conclude that CAPD patients have increased apo(a) concentrations which may contribute to their increased risk of cardiovascular disease.

Renal replacement therapy in multiple myeloma and systemic amyloidosis.

Renal failure frequently complicates both multiple myeloma and systemic amyloidosis. Renal replacement therapy (RRT) may be poorly tolerated and its role in such patients is not clearly defined. Of fifty patients (26 males and 24 females) referred to a single centre because of renal failure associated with multiple myeloma or systemic amyloidosis 37 progressed to end-stage renal failure and 30 of these patients received RRT. Nine patients have been treated by CAPD, 13 by haemodialysis, and 8 patients have required both forms of dialysis. Overall one year and two year survival rates were 66% and 57% respectively. The median duration on RRT was 7.5 months (range 1-96 months) with a 51% one year, and a 46% two year survival rate. Of 7 patients with amyloidosis who underwent renal transplantation, 3 died within 6 months of transplantation. Undiagnosed cardiac involvement contributed to this early mortality. We conclude that renal replacement therapy is appropriate for some patients with multiple myeloma and systemic amyloidosis who develop endstage renal failure. Careful assessment and selection of patients is necessary prior to renal transplantation.

Oral papillary squamous cell carcinoma in twelve dogs.

Papillary squamous cell carcinoma (PSCC) is a distinct histological subtype of oral squamous cell carcinoma (SCC), described in both dogs and man. In dogs, PSCC has long been considered a malignant oral tumour of very young animals, but it has recently been reported to occur in adult dogs as well. The aim of this study was to describe the major clinicopathological characteristics of canine oral PSCC (COPSCC). Twelve dogs diagnosed with COPSCC were included in this retrospective study (1990-2012). The majority (75%) of the dogs were >6 years of age (median age 9 years). All tumours were derived from the gingiva of dentate jaws, with 66.7% affecting the rostral aspects of the jaws. The gross appearance of the lesions varied, with one having an intraosseous component only. The majority (91.7%) of the tumours were advanced lesions (T2 and T3), but no local or distant metastases were noted. Microscopically, two patterns were seen: (1) invasion of bone forming a cup-shaped indentation in the bone or a deeply cavitating cyst within the bone (cavitating pattern), (2) histologically malignant growth, but lack of apparent bone invasion (non-cavitating pattern). The microscopical appearance corresponded to imaging findings in a majority of cases, with cavitating forms presenting with a cyst-like pattern of bone loss or an expansile mass on imaging and non-cavitating forms showing an infiltrative pattern of bone destruction on imaging. These features suggest two distinct biological behaviours of COPSCC.

Ganglioneuroma of the brachial plexus in two cockatiels (Nymphicus hollandicus).

Ganglioneuroma involving the brachial plexus, paraspinal ganglia, and cervical-thoracic spinal cord was diagnosed in 2 adult cockatiels (Nymphicus hollandicus). Both birds had a chronic 1-year history of ataxia and perching difficulty. At necropsy, each bird had a unilateral, firm, gelatinous white to tan multilobular mass at the thoracic inlet expanding and partially obliterating the brachial plexus and cervical spinal cord. Histologically, the masses were characterized by a locally infiltrative neoplasm comprised of spindloid cells forming streams and sheets with interspersed distinct neuron cell bodies consistent with ganglion cells. The spindloid cell population was immunohistochemically positive for neurofilament protein in one of the birds.

Shrinkage of dog lobes during air-drying fixation.

Air-drying of canine lung lobes, distended at a constant pressure corresponding to 50% of lobar total lung capacity, resulted in a volume shrinkage of 35.8%. To examine associated changes in shape of the lobes, the shrinkage of three orthogonal directions (x, y, and z) was quantitated by measuring the change in length per unit length (strain; epsilon) of straight lines between pleural markers. Epsilon x = 0.14, epsilon y = 0.22, and epsilon z = 0.12. This inequality of strains indicated that moderate shape changes occurred. The direction of the largest strain component (epsilon y) corresponded to a direction normal to the largest projected surface area of the lobe.

Models of the pressure-volume relationship of the human lung.

The static pressure-volume (PV) curve from TLC to RV of 11 human subjects was fitted by a hyperbolic-sigmoid model: P = k1/(VM--V)+k2/(Vm--V)+k3, where VM and Vm are the upper and lower asymptotes respectively, and k1, k2, k3 are shape constants. Least-squares nonlinear regression was used to evaluate the constants for the individual and mean data. Average SD of residuals was 0.57 cm H2O and average reduction of residual variance was 99.93%. In spite of substantial differences between PV curves, the latter can be modelled accurately. For the mean PV curve, values for VM, Vm and k1, k2, k3 were 110% VC, -4.34% VC, 260 cm H2O/% VC, 50.5 cm H2O/% VC and 3.13 cm H2O respectively. Unlike previously proposed models, the above includes data below FRC. It describes the truly linear portion of the PV curve at and above FRC. The lower inflection point is accomodated at different lung volumes. When used in a compartmental analysis of a homogeneous lung exposed to a constant pleural pressure gradient, it predicts sequential emptying of dependent and nondependent lung regions consistent with that observed experimentally.

Stress at the pleural surface.

The transmission of forces between the visceral and parietal pleural is modelled as being mediated by two distinct pathways: (a) a contact pressure (Pcon) acting on an area of contact (Acon) and (2) a pleural liquid pressure (Pliq) acting on the area of liquid anfractuosities (Aliq). Summation of the forces yields a new equation relating pleural surface pressure (Ppl) to Pcon, Acon, Pliq, and Aliq. A complete solution of the equation is restricted by present limitations on measurement technology. However, assuming that the volume of pleural liquid is constant during tidal breathing, analysis of the model explains the findings that tidal swings in Pliq (deltaPliq) are sometimes greater than tidal swings in Ppl (deltaPpl). It also predicts that the influence of a change of lung elastic recoil on Pliq may be different in magnitude than its effect on Ppl. Therefore deltaPliq is not necessarily equivalent to deltaPpl.