Alan R Doster

Publications of Alan R Doster

• Inflammatory mammary carcinoma with metastasis to the brain and distant organs in a spayed Shih Tzu dog.

  Authors: Jong-Hyuk Kim, Keum-Soon Im, Na-Hyun Kim, Seung-Ki Chon, Alan R Doster, Jung-Hyang Sur

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 09/2011; 23(5):1079-82.

  Inflammatory mammary carcinoma (IMC) is a specific type of rare, very aggressive, and highly metastatic mammary cancer in both human beings and dogs. A 10-year-old female spayed Shih Tzu dog wasInflammatory mammary carcinoma (IMC) is a specific type of rare, very aggressive, and highly metastatic mammary cancer in both human beings and dogs. A 10-year-old female spayed Shih Tzu dog was diagnosed with secondary IMC. At necropsy, brain metastasis of mammary neoplastic cells was observed in tissues of the cerebrum and cerebellum. Metastases were also found in other distant organs such as heart, lung, liver, spleen, and inguinal lymph node. There is limited data about the metastasis of IMC and its pattern. The current report of IMC with brain metastases contributes to the understanding of metastatic IMC.

• Distribution and characterization of IL-10-secreting cells in lymphoid tissues of PCV2-infected pigs.

  Authors: Alan R Doster, Sakthivel Subramaniam, Ji Young Yhee, Byung Joon Kwon, Chi Ho Yu, So Young Kwon, Fernando A Osorio, Jung Hyang Sur

  Journal of veterinary science. 09/2010; 11(3):177-83.

  Distribution and characterization of interlukin-10 (IL-10)-secreting cells in lymphoid tissues of pigs naturally infected with porcine circovirus type 2 (PCV2) were evaluated in accordance with PCV2Distribution and characterization of interlukin-10 (IL-10)-secreting cells in lymphoid tissues of pigs naturally infected with porcine circovirus type 2 (PCV2) were evaluated in accordance with PCV2 antigen detection. After screening a total of 56 pigs showing the symptoms of postweaning multisystemic wasting syndrome (PMWS), 15 pigs were PCV2 positive and 5 pigs, which showed stronger positive signals over multiples tissues were further investigated. This study showed that in PCV2-infected lymphoid tissues, particularly mandibular lymph node, spleen and tonsil, IL-10 expression was mainly localized in T-cell rich areas but rarely in B cell rich areas. IL-10 was highly expressed in bystander cells but rarely in PCV2-infected cells. Elevated IL-10 expression was predominantly associated with T cells, but rarely with B cells or with macrophages. The results of this study provide evidence for the role of IL-10 in chronic PCV2 infection and its relation to PCV2 antigen in affected tissues. Constantly elevated levels of IL-10 lead to immunosuppression in persistent and chronic viral infections. The increased IL-10 expression observed in PCV2 infection in this study suggests that IL-10-mediated immunosuppression may play an important role in the pathogenesis and maintenance of naturally occurring PCV2 infection.

• Bovine atypical interstitial pneumonia.

  Authors: Alan R Doster

  The Veterinary clinics of North America. Food animal practice. 07/2010; 26(2):395-407.

  Bovine atypical interstitial pneumonia (AIP) is a multifaceted disease with several known causes or clinical presentations. Multiple causal agents and management practices have been associated withBovine atypical interstitial pneumonia (AIP) is a multifaceted disease with several known causes or clinical presentations. Multiple causal agents and management practices have been associated with development of the condition. The sporadic incidence and development of disease in a variety of circumstances argues against a common infectious agent, although cases of AIP are often complicated with bacterial, viral, or mycoplasmal organisms. Lesions develop and progress as a basic response of the lung to injury. Metabolic activation of naturally occurring xenobiotic compounds such as 3-methyl indole, perilla ketone, and 4-ipomeanol produce a clinical syndrome that is indistinguishable from naturally occurring AIP. Pulmonary injury is mediated by formation and activation of intermediate electrophilic compounds that covalently bind to cellular proteins and nucleic acids and ultimately cause cell death. Clara cells (nonciliated bronchiolar) and type I alveolar epithelial cells are primarily responsible for metabolism and activation of these naturally occurring xenobiotics.

• First record of pseudorabies in feral Swine in nebraska.

  Authors: Sam Wilson, Alan R Doster, Justin D Hoffman, Scott E Hygnstrom

  Journal of wildlife diseases. 08/2009; 45(3):874-6.

  In 2007, two new populations of feral swine were discovered in Nance and Valley counties, Nebraska, USA. Necropsies and serologic testing was done on two individuals from the Nance County herd.In 2007, two new populations of feral swine were discovered in Nance and Valley counties, Nebraska, USA. Necropsies and serologic testing was done on two individuals from the Nance County herd. Results indicated that a lactating sow had positive antibodies for pseudorabies virus (PRV). Investigations conducted by Nebraska Game and Parks Commission Law Enforcement division confirmed that the infected individual was transported illegally to Nebraska, USA, from Texas, USA. All domestic swine herds located within an 8 km radius of the infected individual tested negative for antibodies to PRV. Our results provide a clear example of how diseases can spread because of anthropogenic activities and highlight the need for disease surveillance and monitoring in the import of invasive species.

• Characterization of a Helicobacter hepaticus putA mutant strain in host colonization and oxidative stress.

  Authors: Navasona Krishnan, Alan R Doster, Gerald E Duhamel, Donald F Becker

  Infection and immunity. 08/2008; 76(7):3037-44.

  Helicobacter hepaticus is a gram-negative, spiral-shaped microaerophilic bacterium associated with chronic intestinal infection leading to hepatitis and colonic and hepatic carcinomas in susceptibleHelicobacter hepaticus is a gram-negative, spiral-shaped microaerophilic bacterium associated with chronic intestinal infection leading to hepatitis and colonic and hepatic carcinomas in susceptible strains of mice. In the closely related human pathogen Helicobacter pylori, L-proline is a preferred respiratory substrate and is found at significantly high levels in the gastric juice of infected patients. A previous study of the proline catabolic PutA flavoenzymes from H. pylori and H. hepaticus revealed that Helicobacter PutA generates reactive oxygen species during proline oxidation by transferring electrons from reduced flavin to molecular oxygen. We further explored the preference for proline as a respiratory substrate and the potential impact of proline metabolism on the redox environment in Helicobacter species during host infection by disrupting the putA gene in H. hepaticus. The resulting putA knockout mutant strain was characterized by oxidative stress analysis and mouse infection studies. The putA mutant strain of H. hepaticus exhibited increased proline levels and resistance to oxidative stress relative to that of the wild-type strain, consistent with proline's role as an antioxidant. The significant increase in stress resistance was attributed to higher proline content, as no upregulation of antioxidant genes was observed for the putA mutant strain. The wild-type and putA mutant H. hepaticus strains displayed similar levels of infection in mice, but in mice challenged with the putA mutant strain, significantly reduced inflammation was observed, suggesting a role for proline metabolism in H. hepaticus pathogenicity in vivo.

• Hematogenous metastasis of embryonal rhabdomyosarcoma originating from skeletal muscle in a young dog.

  Authors: Ji-Young Yhee, Dae-Hyun Kim, Du-Na Hwang, Chang-Taek Moon, Chi-Ho Yu, Hwi-Yool Kim, Alan R Doster, Jung-Hyang Sur

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 04/2008; 20(2):243-6.

  An 8-month-old, intact male Golden Retriever with a history of left forelimb lameness for 2 months was presented to the Veterinary Medical Teaching Hospital of Konkuk University (Seoul, Korea).An 8-month-old, intact male Golden Retriever with a history of left forelimb lameness for 2 months was presented to the Veterinary Medical Teaching Hospital of Konkuk University (Seoul, Korea). Results of a physical examination revealed a mass in the left axillary region. A thoracic radiography showed an osteolytic lesion in the scapula and the presence of a soft tissue density from the thoracic wall to the scapula. A computerized tomography revealed a mass invading into the scapula, and small nodules in the lung that suggested metastasis. At necropsy, a pale-yellow, irregular, firm, 8 x 10 x 5 cm mass extended from axillary region and destroyed the scapular. In addition, small nodules were noted in the lung. On microscopic examination, the mass consisted of round-to-oval cells, with eccentrically located hyperchromatic nuclei and eosinophilic cytoplasm in fibromyxoid stroma. Tumor cells were observed in blood vessels in the primary mass. Tumor cells strongly expressed vimentin, desmin, and myoglobin. In phosphotungstic acid-hematoxylin staining, cross-striations were detected in rhabdomyoblasts. In periodic acid-Schiff reaction, only a few cells were detected. The diagnosis was primary rhabdomyosarcoma of the appendicular muscle of a young dog. The tumor presumably originated in the skeletal muscle of the limb, invaded into the adjacent scapular bone, and metastasized to the lung.

• Clinical, histopathological and immunohistochemical findings in a case of megakaryoblastic leukemia in a dog.

  Authors: Hee-Myung Park, Alan R Doster, Roksana E Tashbaeva, Young-Mee Lee, Young S Lyoo, Sang Jin Lee, Hee-Jung Kim, Jung-Hyang Sur

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 06/2006; 18(3):287-91.

  The clinical, hematological, and histopathologic features of megakaryoblastic leukemia (M7) were investigated in a 10-year-old female Shih-Tzu dog. Megakaryoblastic leukemia was diagnosed usingThe clinical, hematological, and histopathologic features of megakaryoblastic leukemia (M7) were investigated in a 10-year-old female Shih-Tzu dog. Megakaryoblastic leukemia was diagnosed using anti-human platelet glycoprotein (GP IIIa) and anti-human von Willebrand factor (vWF) antibodies. The expression of CD antigen on megakaryoblasts was also assessed using a CD79a monoclonal antibody. Immunological markers allowed visualization of neoplastic megakaryocytes. Antibodies against platelet GP IIIa were demonstrated to be the most useful for the diagnosis of megakaryoblastic leukemia of paraffin-embedded canine tissues. Hematological and histological data coupled with immunohistochemical reactivity for platelet GP IIIa, vWF, and CD79a antigen in blast cells confirmed a diagnosis of M7 megakaryoblastic leukemia.

• Duration of infection and proportion of pigs persistently infected with porcine reproductive and respiratory syndrome virus.

  Authors: Robert W Wills, Alan R Doster, Judith A Galeota, Jung-Hyang Sur, Fernando A Osorio

  Journal of clinical microbiology. 02/2003; 41(1):58-62.

  Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) persistence in individual pigs is essential to the development of successful control programs. The objectivesUnderstanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) persistence in individual pigs is essential to the development of successful control programs. The objectives of this study were to investigate the proportion of inoculated pigs that become persistently infected with PRRSV and the duration of their infection. Additionally, different diagnostic techniques that detect persistent infections were compared. Twenty-eight 35-day-old pigs were inoculated with PRRSV. Serum and tonsil biopsy samples were collected on days 0, 7, 14, and 28 and then approximately monthly thereafter until day 251 postinoculation (p.i.). Tonsil, lymph node, and lung samples were collected following euthanasia on day 251 p.i. Virus was isolated from serum and tonsil biopsy samples that had been collected through days 28 and 56 p.i., respectively. Viral RNA was detected by reverse transcription (RT)-PCR in serum and tonsil biopsy samples that had been collected through day 251 p.i., although no serum samples collected from days 84 to 196 p.i. were positive and the presence of infectious PRRSV was not detected by swine bioassay of tissue samples collected at necropsy. The results confirmed that RT-PCR is more sensitive than virus isolation in identifying PRRSV-infected pigs. Six pigs that were persistently infected through days 225 or 251 p.i. remained seropositive throughout the study, although one pig had an enzyme-linked immunosorbent assay sample-to-positive ratio that was only slightly above the cutoff value of 0.40. Twenty of 28 tonsil biopsy samples collected on day 84 p.i. were positive by RT-PCR compared to only 1 positive biopsy sample out of 28 collected on day 119 p.i. The study's results indicate that most pigs clear PRRSV within 3 to 4 months, but that some may remain persistently infected for several months.