J Mansell

Texas A&M University, College Station, Texas, United States

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Publications (25)41.37 Total impact

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    ABSTRACT: Changes in the microbial populations on the skin of animals have traditionally been evaluated using conventional microbiology techniques. The sequencing of bacterial 16S rRNA genes has revealed that the human skin is inhabited by a highly diverse and variable microbiome that had previously not been demonstrated by culture-based methods. The goals of this study were to describe the microbiome inhabiting different areas of the canine skin, and to compare the skin microbiome of healthy and allergic dogs. DNA extracted from superficial skin swabs from healthy (n = 12) and allergic dogs (n = 6) from different regions of haired skin and mucosal surfaces were used for 454-pyrosequencing of the 16S rRNA gene. Principal coordinates analysis revealed clustering for the different skin sites across all dogs, with some mucosal sites and the perianal regions clustering separately from the haired skin sites. The rarefaction analysis revealed high individual variability between samples collected from healthy dogs and between the different skin sites. Higher species richness and microbial diversity were observed in the samples from haired skin when compared to mucosal surfaces or mucocutaneous junctions. In all examined regions, the most abundant phylum and family identified in the different regions of skin and mucosal surfaces were Proteobacteria and Oxalobacteriaceae. The skin of allergic dogs had lower species richness when compared to the healthy dogs. The allergic dogs had lower proportions of the Betaproteobacteria Ralstonia spp. when compared to the healthy dogs. The study demonstrates that the skin of dogs is inhabited by much more rich and diverse microbial communities than previously thought using culture-based methods. Our sequence data reveal high individual variability between samples collected from different patients. Differences in species richness was also seen between healthy and allergic dogs, with allergic dogs having lower species richness when compared to healthy dogs.
    PLoS ONE 01/2014; 9(1):e83197. · 3.53 Impact Factor
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    ABSTRACT: Due to their ability to release inflammatory mediators, such as histamine, mast cells are potentially important in gastrointestinal disease. The purpose of this study was to measure N-methylhistamine (NMH), a histamine metabolite, in fecal and urine samples from dogs with chronic gastrointestinal disease. Fecal and urinary NMH concentrations were compared between dogs with chronic gastrointestinal disease and control dogs, and/or to control ranges. Correlation between fecal and urinary NMH concentrations, serum C-reactive protein (CRP) concentration, the clinical disease activity index (CCECAI), and gastrointestinal mucosal mast cell numbers (where available) in dogs with gastrointestinal disease was evaluated. Seven of 16 dogs with gastrointestinal disease had increased urinary or fecal NMH concentrations, but there was no correlation between NMH concentrations and the CCECAI or mucosal mast cells numbers. Urinary NMH concentrations were positively associated with histological grading and serum CRP concentrations. The lack of correlation between NMH concentrations and the CCECAI suggests that NMH may not be a good marker for clinical disease activity in dogs as determined by the CCECAI. Based on their association with severity of intestinal mucosal inflammation, urinary NMH concentrations may potentially have clinical utility as a marker of intestinal inflammation in certain groups of dogs with chronic gastrointestinal disease, but future studies in a larger number of dogs are necessary to further characterize the role of mast cell-mediated inflammation in dogs with chronic gastrointestinal disease.
    The Veterinary Journal. 01/2014;
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    ABSTRACT: Significant interobserver variability in the diagnostic interpretation of endoscopic gastrointestinal (GI) specimens exists even with the use of World Small Animal Veterinary Association (WSAVA) standardization criteria. Chi-square analyses compared the extent of pathologists' agreement for microarchitectural features of inflammation in endoscopic specimens obtained from 253 animals of the original WSAVA study. Patterns of agreement between pathologists were classified as broad (3/4 pathologists agreed), dichotomous (2/4 pathologists agreed), or divergent (no agreement between pathologists). The simplified model for GI inflammation was based on those parameters for which the pathologists had either broad or minimally divergent opinions of histopathologic significance. In this model, the parameters chosen were as follows: gastric parameters (intraepithelial lymphocytes [IELs], lamina propria [LP] infiltrates, and mucosal fibrosis), duodenal parameters (villus atrophy, epithelial injury, IELs, crypt changes, and LP infiltrates), and colonic parameters (epithelial injury, crypt dilation, fibrosis, LP infiltrates, and goblet cell depletion). Preliminary data using this simplified model showed excellent correlation between pathologists in defining the presence and extent of GI inflammation in dogs.
    Veterinary Pathology 11/2013; · 1.93 Impact Factor
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    ABSTRACT: BACKGROUND: Limited data exist regarding influence of endoscopic forceps on duodenal mucosal biopsy quality and adequacy for histologic examination/assessment in dogs. HYPOTHESIS/OBJECTIVES: Hypothesizing that larger forceps would procure superior specimens, we evaluated effect of 6 disposable forceps on duodenal biopsy weight, depth, crush artifact, and adequacy for histologic examination/assessment. ANIMALS: Seventeen healthy adult dogs. METHODS: Prospective study. Two operators each obtained 4 duodenal specimens from each dog with each forceps. Lightest sample discarded. One pathologist evaluated blindly other 3 specimens. A total of 612 specimens evaluated. Results analyzed by one-way ANOVA of forceps effects with dog as blocking factor. Posthoc pairwise comparisons examined with Tukey's test when indicated. RESULTS: Biopsies performed with large capacity forceps heavier (10.56 ± 0.90 and 11.6 ± 0.62 mg (mean ± SD) versus 5.55 ± 0.53 to 8.61 ± 0.49; P < .0001) and adequacy for histologic examination/assessment superior to standard oval and 'pediatric' (scores 2.52 ± 0.41 and 2.58 ± 0.37 versus 2.08 ± 0.33 and 2.14 ± 0.29; P < .0001). No statistically significant difference in depth scores. Large capacity forceps with spike associated with less crush artifact than all smaller forceps (scores 1.19 ± 0.16 versus 1.38 ± 0.21 to 1.52 ± 0.21; P < .0001). In same size forceps, presence of spike had no effect on crush artifact and adequacy for histologic examination/assessment (P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Large capacity forceps are superior, providing higher quality and greater numbers of samples achieving adequacy for histologic examination/assessment. Choice of endoscopic biopsy forceps for duodenal samples influences sample volume and diagnostic utility.
    Journal of Veterinary Internal Medicine 04/2013; · 2.06 Impact Factor
  • Journal of the American Veterinary Medical Association 01/2013; 242(1):43-5. · 1.72 Impact Factor
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    ABSTRACT: Cutaneous toxoplasmosis has been previously reported in human beings, rarely reported in cats, and reported in 1 dog with systemic toxoplasmosis. The present report describes 2 cases of cutaneous toxoplasmosis in 2 dogs treated with immunosuppressive therapy. One of the dogs developed generalized cutaneous pustules and pruritus, and the other dog only had a single subcutaneous nodule. Microscopically, skin biopsies showed moderate to severe pyogranulomatous and necrotizing dermatitis and panniculitis, with multifocal vasculitis and vascular thrombosis. Single or aggregates of protozoal tachyzoites were mostly intracytoplasmic and occasionally extracellular. The etiology was confirmed in both cases by immunohistochemistry and by polymerase chain reaction assays, which were followed by nucleic acid sequencing. Both patients were treated with clindamycin. The dog with generalized lesions developed pulmonary and neurological signs and was euthanized. The dog with a single nodule recovered completely with no remission of cutaneous lesions.
    Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 05/2012; 24(3):636-40. · 1.18 Impact Factor
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    ABSTRACT: The schistosome Heterobilharzia americana infects dogs, raccoons, and other mammals in the southeastern United States. Migration of eggs into the liver results in parasitic granulomas with varying degrees of fibrosis and inflammation. Recently, hepatic parasitic granulomas in horses were shown to be caused by H. americana infection. In the present study, samples of liver from 11 of 12 horses with hepatic granulomas identified at necropsy (n = 11) or surgical biopsy (n = 1) were used for DNA extraction, polymerase chain reaction amplification and sequencing using primers specific for a portion of the H. americana small subunit ribosomal RNA gene. A polymerase chain reaction amplicon of the correct size was produced from the extracted DNA in 8 of the 11 horses. Amplicons from 5 of the 8 positive horses were sequenced and had 100% identity with H. americana. In all but 2 of the 12 horses, Heterobilharzia was not responsible for the primary clinical disease, and the hepatic granulomas were considered an incidental finding.
    Veterinary Pathology 01/2012; 49(3):552-6. · 1.93 Impact Factor
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    ABSTRACT: Endoscopic duodenal biopsies are relatively convenient, minimally invasive tests for infiltrative intestinal disorders of cats. Ileal endoscopic biopsies might not be performed because of technical difficulty and effort required to prepare the colon. It is not known whether or not histopathology of feline duodenal and ileal biopsies for detection of inflammatory bowel disease (IBD) and small cell lymphoma (SC-LSA) provides comparable results. To evaluate the agreement between endoscopic biopsies of duodenum and ileum in cats with IBD and SC-LSA. Seventy client-owned cats with gastrointestinal disease and adequate duodenal and ileal tissue biopsies obtained endoscopically. Retrospective study: Search of medical records of cats with enteropathy and endoscopy. Samples were blinded and re-evaluated by single pathologist (JM) for quality, number of biopsies, and diagnosis according to WSAVA standards. Agreement of IBD and SC-LSA diagnoses among biopsy sites assessed using Cohen's Kappa. Eighteen of 70 cats (26%) were diagnosed with SC-LSA in duodenum, ileum, or both. Of these 18 cats, 7 (39%) were diagnosed with only duodenal SC-LSA, 8 (44%) were diagnosed with only ileal SC-LSA, and 3 (17%) had SC-LSA in both duodenum and ileum. There was poor agreement on diagnosis between duodenal and ileal biopsies (kappa = 0.23). Although review by a single pathologist remains a limitation of this study, results suggest that there is a population of cats in which diagnosis of SC-LSA can be found only by evaluation of ileal biopsies. Clinicians should consider performing both upper and lower GI endoscopic biopsies in cats with infiltrative small bowel disease.
    Journal of Veterinary Internal Medicine 11/2011; 25(6):1253-7. · 2.06 Impact Factor
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    ABSTRACT: Mycotic meningoencephalitis in dogs may manifest as a primary disease of the central nervous system or as a part of disseminated infection. Fungi belonging to the genus Bipolaris are saprophytic plant pathogens and can cause disease in humans. The authors report a case of Bipolaris infection in a dog with granulomatous meningoencephalitis, nephritis, and vasculitis. The clinical and histological features resembled those of the more common aspergillosis, thus warranting confirmation by molecular methods. Polymerase chain reaction and sequence analysis identified Bipolaris from the brain lesion, indicating its involvement in the disease. To the authors' knowledge, this is the first reported case of meningoencephalitis caused by this fungus in a domestic animal.
    Veterinary Pathology 05/2011; 48(3):754-7. · 1.93 Impact Factor
  • Michael Willard, Joanne Mansell
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    ABSTRACT: There has been increasing awareness that the severity of histopathologic lesions does not always correlate with the severity of clinical signs. Several grading systems for gastrointestinal histopathologic lesions have been generated, but there has been no widespread acceptance of one system. The World Small Animal Veterinary Association sponsored a gastrointestinal study group that produced a template of histologic changes in the gastrointestinal tract of the feline and canine in an attempt to generate widespread acceptance of a grading system. This article outlines the progress, pitfalls, and challenges in correlating histopathologic changes in the gastrointestinal tract with clinical activity.
    Veterinary Clinics of North America Small Animal Practice 03/2011; 41(2):457-63. · 1.43 Impact Factor
  • A M Arenas-Gamboa, J Mansell
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    ABSTRACT: Haemangiosarcomas (HSAs) are malignant tumours of endothelial cell origin. Epithelioid HSA is a variant of the histologically conventional HSA that has little or no morphological evidence of a vascular origin and has been reported rarely in domestic animals. The following report documents six cases of equine epithelioid HSA occurring in the ocular tissues of horses with a mean age of 19.8 years at the time of diagnosis. Microscopically, all of the lesions consisted of solid sheets or cords of epithelioid cells with rare narrow clefts or small spaces containing erythrocytes that were often the only feature indicating a vascular origin. On immunohistochemistry, the neoplastic cells expressed vimentin, CD31 and factor VIII-related antigen, but not cytokeratin, indicating an endothelial nature.
    Journal of comparative pathology 01/2011; 144(4):328-33. · 1.73 Impact Factor
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    ABSTRACT: A 6-year-old castrated male ferret presented with multiple black and tan proliferative skin lesions. Histologically, the lesions were characterized by multifocal plaques of irregular epidermal hyperplasia and full-thickness dysplasia, with loss of normal epithelial stratification, loss of nuclear polarity, and rare eosinophilic intranuclear inclusion bodies in the superficial layers of the epidermis. Immunohistochemical staining with a monoclonal antibody against papillomaviruses was strongly immunoreactive. Ultrastructurally, large numbers of hexagonal viral particles approximately 50 nm were observed within the nuclei of dysplastic superficial keratinocytes. To the authors' knowledge, this is the first report of a ferret multicentric squamous cell carcinoma in situ associated with papillomavirus.
    Veterinary Pathology 05/2010; 47(5):964-8. · 1.93 Impact Factor
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    Journal of Veterinary Internal Medicine 01/2010; 24(1):10-26. · 2.06 Impact Factor
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    ABSTRACT: Prior studies failed to detect significant association between hypoalbuminemia and small intestinal lesions. Use of pictorial templates will enhance consistency of interpathologist interpretation and identification of intestinal lesions associated with hypoalbuminemia. Tissues from 62 dogs and 25 cats examined as clinical cases at 7 referral veterinary practices in 4 countries. Retrospective, observational study. Histopathology slides from sequential cases undergoing endoscopic biopsy were examined by 4 pathologists by pictorial templates. Changes for 9 microscopic features were recorded as normal, mild, moderate or severe, and 2- and 4-point scales were tested for consistency of interpretation. Logistic regression models determined odds ratios (OR) of histologic lesions being associated with hypoalbuminemia while kappa statistics determined agreement between pathologists on histologic lesions. There was poor agreement (kappa = -0.013 to 0.3) between pathologists, and institution of origin of slides had effect (kappa = 1.0 for 3 of 4 lesions on slides from Institution 5) on agreement between pathologists on selected histologic features. Using 2 point as opposed to 4-point grading scale increased agreement between pathologists (maximum kappa = 0.69 using 4-point scale versus maximum kappa = 1.0 using 2-point scale). Significant association (P = .019- .04; 95% OR = 3.14-10.84) between lacteal dilation and hypoalbuminemia was found by 3 pathologists. Substantial inconsistency between pathologists remains despite use of pictorial template because of differences in slide processing. Distinguishing between mild and moderate lesions might be important source of the disagreement among pathologists.
    Journal of Veterinary Internal Medicine 11/2009; 24(1):84-9. · 2.06 Impact Factor
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    ABSTRACT: The quality of histopathology slides of endoscopic biopsies from different laboratories varies, but the effect of biopsy quality on outcome is unknown. The ability to demonstrate a histologic lesion in the stomach or duodenum of a dog or cat is affected by the quality of endoscopic biopsy samples submitted. More endoscopic samples are needed to find a lesion in poor-quality tissue specimens. Tissues from 99 dogs and 51 cats were examined as clinical cases at 8 veterinary institutions or practices in 5 countries. Histopathology slides from sequential cases that underwent endoscopic biopsy were submitted by participating institutions. Quality of the histologic section of tissue (inadequate, marginal, adequate), type of lesion (lymphangiectasia, crypt lesion, villus blunting, cellular infiltrate), and severity of lesion (normal, mild, moderate, severe) were determined. Sensitivity of different quality tissue samples for finding different lesions was determined. Fewer samples were required from dogs for diagnosis as the quality of the sample improved from inadequate to marginal to adequate. Duodenal lesions in cats displayed the same trend except for moderate duodenal infiltrates for which quality of tissue sample made no difference. Gastric lesions in dogs and mild gastric lesions in cats had the same trend, whereas the number of tissue samples needed to diagnose moderately severe gastric lesions in cats was not affected by the quality of tissue sample. The quality of endoscopically obtained tissue samples has a profound effect on their sensitivity for identifying certain lesions, and there are differences between biopsies of canine and feline tissues.
    Journal of Veterinary Internal Medicine 08/2008; 22(5):1084-9. · 2.06 Impact Factor
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    ABSTRACT: Dermatomyositis (DM) is a canine and human inflammatory disease of the skin and muscle that is thought to be autoimmune in nature. In dogs, DM occurs most often in the rough collie and Shetland sheepdog. Characteristic skin lesions typically develop on the face, ears, tail, and distal extremities. The severity of lesions varies and is thought to increase with stressful stimuli. Previous studies in the collie suggest that DM is inherited in an autosomal dominant fashion with incomplete penetrance. The work presented here concerns gene transcripts profiling and immunobiology of DM in the Shetland sheepdog. Gene transcript profiles were generated for affected and normal skin using a canine-specific oligonucleotide array having 49,929 probe sets. Two-hundred and eight-five gene transcripts, many of which are involved in immune function, were found to be differentially regulated in these tissues. Also reported are Western blot, immunohistochemistry, and immunofluorescence analyses which showed that staining patterns with sera from normal and affected dogs are quite similar. While our work suggests that canine DM is a disease that may be immune mediated, it did not detect the production of specific disease-associated autoantibodies.
    Veterinary Dermatology 05/2008; 19(2):52-8. · 2.02 Impact Factor
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    ABSTRACT: The characterization of inflammatory change in endoscopic biopsy samples of the gastrointestinal mucosa is an increasingly important component in the diagnosis and management of canine and feline gastrointestinal disease. Interpretation has hitherto been limited by the lack of standard criteria that define morphological and inflammatory features, and the absence of such standardization has made it difficult, if not impossible, to compare results of retrospective or prospective studies. The World Small Animal Veterinary Association (WSAVA) Gastrointestinal Standardization Group was established, in part, to develop endoscopic and microscopical standards in small animal gastroenterology. This monograph presents a standardized pictorial and textual template of the major histopathological changes that occur in inflammatory disease of the canine and feline gastric body, gastric antrum, duodenum and colon. Additionally, a series of standard histopathological reporting forms is proposed, to encourage evaluation of biopsy samples in a systematic fashion. The Standardization Group believes that the international acceptance of these standard templates will advance the study of gastrointestinal disease in individual small companion animals as well as investigations that compare populations of animals.
    Journal of Comparative Pathology 01/2008; 138 Suppl 1:S1-43. · 1.38 Impact Factor
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    ABSTRACT: Liposarcomas are rare neoplasms in domestic animals, but have been reported to occur in many species. In humans, liposarcoma is one of the most common malignant mesenchymal tumors. Classification of liposarcomas in humans has been well established and categorization by type can be of prognostic value; no such unique classification scheme has been established for liposarcomas in animals. Liposarcoma of the head and neck in humans are uncommon, and are rarely reported in the nasal cavity, sinuses, and nasopharynx. To our knowledge, a liposarcoma has never been reported in the nasal cavity of a domestic animal. In this report we describe a liposarcoma that developed in the nasal cavity of a cow, with local invasion into the oral cavity.
    Veterinary Pathology 10/2006; 43(5):793-7. · 1.93 Impact Factor
  • Jason B Osterstock, Joanne L Mansell, Allen J Roussel
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    ABSTRACT: Prototheca spp are achlorophyllic saprophytic algae found in wastewater, sewage, agricultural waste, and possibly elsewhere in the environment. Infections with these organisms have been reported in cattle, humans, and dogs; affected cattle commonly develop mastitis. A 5-year-old Brahman-cross bull was evaluated because of a history of diarrhea and weight loss. The history and physical examination and clinicopathologic findings were similar to those associated with granulomatous enteritis caused by Mycobacterium avium subsp paratuberculosis (Johne's disease), which is the most common protein-losing enteropathy of cattle. However, diagnostic tests for paratuberculosis yielded negative results. Biopsy specimens from the ileum, jejunum, and ileocecal lymph node were collected for histologic examination and preparation of tissue impression smears; Prototheca-like organisms were identified. Because of the poor prognosis associated with this infection and the lack of safe and economical therapeutic agents for cattle, the owner decided to euthanatize the bull. Infection with Prototheca organisms was confirmed postmortem. As this case illustrates, protothecosis may be a cause of granulomatous enteritis in cattle.
    Journal of the American Veterinary Medical Association 12/2005; 227(9):1476-9, 1418. · 1.72 Impact Factor
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    ABSTRACT: A 13-year-old neutered male Jack Russell Terrier (Parson Russell Terrier) was presented to the Texas Veterinary Medical Center with a history of lethargy, depression, vomiting, and fever. The dog had mildly regenerative anemia, severe thrombocytopenia and low antithrombin activity. Marked splenomegaly was found on physical examination and imaging studies, and malignant round cell neoplasia and marked extramedullary hematopoiesis were diagnosed on aspirates of the spleen. The dog underwent exploratory laporatomy and splenectomy. Because of a rapid decline in clinical condition postsurgery, the dog was euthanized. Splenic and hepatic biopsies were submitted for histopathologic evaluation. A neoplastic population of round cells was found throughout the splenic parenchyma and within hepatic sinusoids. The neoplastic cells stained strongly positive for CD3 (T-cell marker) and were negative for CD79a (B-cell marker) and lysozyme (histiocytic marker). A diagnosis of T-cell lymphoma was confirmed by assessment of T-cell clonality using canine-specific polymerase chain reaction-based techniques. Although expression of the gammadelta T-cell receptor was not evaluated, this case shares many similarities with a rare syndrome in humans known as hepatosplenic gammadelta T-cell lymphoma.
    Veterinary Clinical Pathology 02/2004; 33(2):105-10. · 1.29 Impact Factor