Endoscopic transesophageal vs. thoracoscopic removal of mediastinal lymph nodes: a prospective randomized trial in a long term animal survival model.

BACKGROUND AND STUDY AIMS: In cases where biopsies remain inconclusive, removal of mediastinal lymph nodes for further analysis requires surgical means. Natural orifice transluminal endoscopic surgery (NOTES) procedures allow incision/closure of the gut wall, which might enable endoscopic excision of pre-marked nodes. The aims of the current study were to investigate the feasibility, safety, and reproducibility of lymph node generation in an animal model to enable endoscopic ultrasound-guided (EUS) lymph node removal (ELR) using transesophageal NOTES access/closure and to compare this procedure with thoracoscopic lymph node removal (TLR) in a randomized long term survival animal study. PATIENTS AND METHODS: Lymph node creation using graphite injection was performed in 12 pigs. After randomization into ELR and TLR groups, lymph nodes were marked with newly developed anchors under EUS guidance and removed using either ELR or TLR. ELR included incision of the esophageal wall and closure after lymph node removal. The main outcome measures were success in lymph node generation, technical success of lymph node removal, complications, and comparability of ELR and TLR. RESULTS: Generation of lymph nodes proved successful in all animals in 46/48 sites injected (96 %). Anchors were placed through the selected nodes in a mean of 9.4 minutes. TLR and ELR were successful in all cases. One bleeding occurred during esophageal incision in ELR, which was stopped endoscopically. After lymph node removal, endoscopic suturing of the incision took a mean of 18 minutes. Procedure time was longer for ELR than TLR (mean 48 vs. 42 minutes). All animals survived the procedures. Autopsy after 4 weeks showed two thoracic wall abscesses in the TLR group and none in the ELR group.  Microscopic analysis revealed well healed esophageal scars. CONCLUSION: ELR proved to be feasible in this limited sample size and complications were not observed more frequently in this group than in the TLR group.

Randomized comparative long-term survival study of endoscopic and thoracoscopic esophageal wall repair after NOTES mediastinoscopy in healthy and compromised animals.

BACKGROUND AND STUDY AIMS: Natural orifice transluminal endoscopic surgery (NOTES) has not yet been widely adopted because of lack of suitable equipment and fear of possible serious complications, especially in the mediastinum. We compared endoscopic with thoracoscopic esophageal wall repair after full-thickness esophageal wall incision (FTEI) and NOTES mediastinoscopy in healthy versus compromised animals. METHODS: After FTEI for mediastinoscopy, 24 pigs (12 healthy, 12 compromised) were randomly allocated to endoscopic or thoracoscopic repair (each arm of each group, n = 6). They were kept alive for 3 months after endoscopic closure with prototype T-anchor suturing or thoracoscopic repair. RESULTS: FTEI and mediastinoscopy were uneventful in all as was the initial repair of the incision (mean repair times: thoracoscopic 65 +/- 3.2 minutes, endoscopic 52 +/- 5.1 minutes; P < 0.0005). Post procedure, all 12 healthy pigs thrived with no complications or deaths. Two compromised animals died during the preparation period, and had to be replaced. In the compromised group, during endoscopic repair, 2 / 6 pigs suffered from gastric reflux into esophagus and mediastinum; the repair was completed and the pigs kept alive; one subsequently died of mediastinitis, and in the other, autopsy showed a gastric abscess in the lower mediastinum. Regarding the compromised thoracoscopic subgroup, one animal died from mediastinitis and all had abscesses at or near the incision sites. CONCLUSION: Transesophageal mediastinoscopy could be performed equally well as the transthoracic procedure, both in healthy and compromised animals. However, on follow-up, the compromised animals had worse outcomes, with more complications and two deaths (17 %), one in each arm.

Beyond NOTES: randomized controlled study of different methods of flexible endoscopic hemostasis of artificially induced hemorrhage, via NOTES access to the peritoneal cavity.

BACKGROUND AND STUDY AIM: Significant hemorrhage is a likely complication during natural orifice transluminal endoscopic surgery (NOTES) procedures. We tested three different prototype devices (involving endoscopic suturing, monopolar forceps, and forced argon plasma coagulation [FAPC]) for treatment of acute bleeding in a survival animal model. METHOD: Using transgastric access (TGA) or transvaginal access (TVA), the endoscope was introduced into the peritoneal cavity and the first side-branch of the gastroepiploic artery (1aGE) was cut before the different hemostatic methods were applied. RESULTS: Sutures could not be placed quickly enough before vision was inhibited. With monopolar forceps via TGA, the time to control bleeding was 10 - 140 s (mean 58 +/- 41 s) and with TVA it was 25 - 115 s (mean 57 +/- 26 s) (P = 0.54). It was not possible to stop the bleeding in 4/6 animals with TGA access and in 3/6 with TVA, and FAPC was needed to entirely stop it, taking a further 10 - 280 s (TGA mean 126 +/- 90 s, 34 - 242 s; TVA mean 152 +/- 61 s; P = 0.42). Using FAPC with TGA took 4 - 72 s (mean 28 +/- 20 s) to stop the bleeding, and 16 - 41 s (mean 24 +/- 9.4 s) with TVA ( P = 0.64). As the FAPC technique was relatively so much better, additional treatment of bleeding from the main gastroepiploic artery (aGe) was added in four cases for each method of access; this was successful but took significantly longer, with TGA at 10 - 260 s and with TVA at 30 - 172 s (means 98 +/- 82, 117 +/- 54 s, respectively; not significant). CONCLUSION: Regarding the three methods tested, the new prototype FAPC device allowed hemostasis of notable bleeding from a major vessel even more quickly than forceps coagulation of a bleeding side branch. More studies are needed to further explore this potentially very valuable tool.

Pathogenesis and immunopathology of systemic and nervous canine distemper.

Canine distemper is a worldwide occurring infectious disease of dogs, caused by a morbillivirus, closely related to measles and rinderpest virus. The natural host range comprises predominantly carnivores. Canine distemper virus (CDV), an enveloped, negative-sense RNA virus, infects different cell types, including epithelial, mesenchymal, neuroendocrine and hematopoietic cells of various organs and tissues. CDV infection of dogs is characterized by a systemic and/or nervous clinical course and viral persistence in selected organs including the central nervous system (CNS) and lymphoid tissue. Main manifestations include respiratory and gastrointestinal signs, immunosuppression and demyelinating leukoencephalomyelitis (DL). Impaired immune function, associated with depletion of lymphoid organs, consists of a viremia-associated loss of lymphocytes, especially of CD4+ T cells, due to lymphoid cell apoptosis in the early phase. After clearance of the virus from the peripheral blood an assumed diminished antigen presentation and altered lymphocyte maturation cause an ongoing immunosuppression despite repopulation of lymphoid organs. The early phase of DL is a sequel of a direct virus-mediated damage and infiltrating CD8+ cytotoxic T cells associated with an up-regulation of pro-inflammatory cytokines such as interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-alpha and IL-12 and a lacking response of immunomodulatory cytokines such as IL-10 and transforming growth factor (TGF)-beta. A CD4+-mediated delayed type hypersensitivity and cytotoxic CD8+ T cells contribute to myelin loss in the chronic phase. Additionally, up-regulation of interferon-gamma and IL-1 may occur in advanced lesions. Moreover, an altered balance between matrix metalloproteinases and their inhibitors seems to play a pivotal role for the pathogenesis of DL. Summarized, DL represents a biphasic disease process consisting of an initial direct virus-mediated process and immune-mediated plaque progression. Immunosuppression is due to early virus-mediated lymphocytolysis followed by still poorly understood mechanisms affecting antigen presentation and lymphocyte maturation.

Predominance of Granular Cell Tumours among Testicular Tumours of Rabbits (Oryctolagus cuniculi f. dom.).

Testicular neoplasms are reported rarely in pet and laboratory rabbits (Oryctolagus cuniculi f. dom.), with interstitial cell tumours being the most commonly described testicular neoplasm. In this retrospective study, paraffin wax-embedded testicles with neoplastic changes from 52 rabbits were investigated. Five out of 52 animals exhibited more than one tumour type, resulting in a total of 57 tumours. Granular cell tumours were the most prevalent neoplasm with 36 examples (63%) out of the 57 testicular tumours. Interstitial cell tumours, Sertoli cell tumours and seminomas occurred less frequently. Granular cell tumours of the testis are rare in rabbits. Histological similarities between granular cell and interstitial cell (Leydig cell) tumours in haematoxylin and eosin-stained tissue sections may lead to misdiagnoses. The periodic acid-Schiff reaction or immunohistochemistry for periaxin and S100 protein, as well as ultrastructural analysis, are useful methods to confirm the diagnosis.

Urethral fistula after resection of a penile fibropapilloma in a Holstein Friesian bull.

INTRODUCTION: A 2-year-old Holstein Friesian bull with a penile tumour was referred to the University of Veterinary Medicine Hannover, Foundation, Germany, where the tumour was resected and diagnosed as a fibropapilloma. A urethral fistula was diagnosed eight days postoperatively and was present nine months later, although the bull had normal copulation behaviour and satisfactory fertility. Surgical removal of fibropapillomas in close proximity to the urethra is an effective treatment. A urethral fistula, which may occur as a postsurgical complication, did not have an adverse effect on copulation capacity and fertility of the bull.

INTRODUCTION: Un taureau Holstein Frisian de 2 ans atteint d'une tumeur du pénis a été référé à l'Université de médecine vétérinaire de Hanovre, Fondation, en Allemagne, où la tumeur a été réséquée et diagnostiquée comme un fibropapillome. Une fistule urétrale a été diagnostiquée huit jours après l'opération et était présente neuf mois plus tard, bien que le taureau ait eu un comportement de copulation normal et une fertilité satisfaisante. L'ablation chirurgicale des fibropapillomes à proximité immédiate de l'urètre constitue un traitement efficace. Une fistule urétrale, qui peut survenir comme complication post-chirurgicale, n'a pas eu d'effet négatif sur la capacité de copulation et la fertilité du taureau.

Listeria monocytogenes septicaemia and concurrent clostridial infection in an adult alpaca (Lama pacos).

A 10-year-old alpaca with a history of anorexia, weight loss and diarrhoea was humanely destroyed and shown to have a multifocal necrotizing hepatitis, splenitis and colitis, as well as an ulcerative to diphtheroid ileitis. Immunohistochemical examination revealed Listeria monocytogenes antigen in the liver and ileum. In addition, L. monocytogenes and Listeria sp.-specific gene fragments were detected by the polymerase chain reaction. L. monocytogenes was isolated from liver and small intestine and Clostridium perfringens type A with beta(2) toxin was found in the small intestine. It is suggested that the infection with C. perfringens type A facilitated the systemic spread of L. monocytogenes.

Atypical Cowpox Virus Infection in a Series of Cats.

Within 4 weeks, five cats with skin lesions affecting the hindlimbs and mainly consisting of oedema, hyperaemia and plaque-like alterations were presented to the same veterinary clinic. The cats were suffering from lameness, trauma, renal insufficiency or complicated tail amputation. Although the lesions seemed unusual for a poxvirus infection, microscopical examination of biopsy samples or specimens taken during necropsy examination revealed ballooning degeneration of keratinocytes with eosinophilic, cytoplasmic inclusion bodies indicative of an orthopoxvirus infection. Cowpox virus infection was verified using immunohistochemistry and virus isolation. Molecular analysis revealed identical haemagglutinin gene sequences in four cases and spatiotemporal circumstances in some cases pointed to hospital-acquired transmission. Unusual manifestations of feline cowpox may have an unexpected risk for human infection.

An Egyptian HPAI H5N1 isolate from clade 2.2.1.2 is highly pathogenic in an experimentally infected domestic duck breed (Sudani duck).

The highly pathogenic avian influenza (HPAI) H5N1 viruses continue to cause major problems in poultry and can, although rarely, cause human infection. Being enzootic in domestic poultry, Egyptian isolates are continuously evolving, and novel clades vary in their pathogenicity in avian hosts. Considering the importance of domestic ducks as natural hosts of HPAI H5N1 viruses and their likelihood of physical contact with other avian hosts and humans, it is of utmost importance to characterize the pathogenicity of newly emerged HPAI strains in the domestic duck. The most recently identified Egyptian clade 2.2.1.2 HPAI H5N1 viruses have been isolated from naturally infected pigeons, turkeys and humans. However, essentially nothing is known about their pathogenicity in domestic ducks. We therefore characterized the pathogenicity of an Egyptian HPAI H5N1 isolate A/chicken/Faquos/amn12/2011 (clade 2.2.1.2) in Sudani duck, a domestic duck breed commonly reared in Egypt. While viral transcription (HA mRNA) was highest in lung, heart and kidney peaking between 40 and 48 hpi, lower levels were detected in brain. Weight loss of infected ducks started at 16 hpi and persisted until 120 hpi. The first severe clinical signs were noted by 32 hpi and peaked in severity at 72 and 96 hpi. Haematological analyses showed a decline in total leucocytes, granulocytes, platelets and granulocyte/lymphocyte ratio, but lymphocytosis. Upon necropsy, lesions were obvious in heart, liver, spleen and pancreas and consisted mainly of necrosis and petechial haemorrhage. Histologically, lungs were the most severely affected organs, whereas brain only showed mild neuronal degeneration and gliosis at 48 hpi despite obvious neurological clinical signs. Taken together, our results provide first evidence that this HPAI H5N1 isolate (clade 2.2.1.2) is highly pathogenic to Sudani ducks and highlight the importance of this breed as potential reservoir and disseminator of HPAI strains from this clade.

Skeletal muscle hypoplasia represents the only significant lesion in peripheral organs of ruminants infected with Schmallenberg virus during gestation.

Schmallenberg virus (SBV), an arbovirus within the family Bunyaviridae, represents a ruminant pathogen that has caused epidemic abortion and birth of malformed or stillborn animals in many European countries since August 2011. Histological and immunohistochemical analysis of peripheral tissues of SBV-infected animals, including lymphoid tissues, endocrine organs and tissues of the gastrointestinal, urogenital and respiratory system, were analyzed in order to elucidate the occurrence of SBV-associated changes and the presence of viral antigens and RNA. Twenty calves and 12 lambs as well as age-matched controls were included in this study. Significant muscular hypoplasia with fatty replacement was noted in affected calves and lambs. In addition, hepatocellular degeneration with lymphohistiocytic inflammation, interstitial fibrosis and biliary hyperplasia was detected in calves. All animals lacked SBV-positive cells in the peripheral organs. These observations resemble those found in Akabane virus- and Cache Valley virus-infected animals and support the occurrence of few residual lesions in peripheral organs following SBV infection.

Vaginal canine transmissible venereal tumour associated with intra-tumoural Leishmania spp. amastigotes in an asymptomatic female dog.

A 2-year-old female boxer dog was presented with a vaginal serosanguineous discharge not associated with oestrus. There was a friable mass occupying the upper caudal part of the vagina. Cytological and histological examination revealed a monomorphic population of neoplastic round cells consistent with canine transmissible venereal tumour (TVT). In addition, Leishmania spp. amastigotes were found within the neoplastic tissue. In order to characterize whether the amastigotes were present inside macrophages and/or neoplastic cells, a co-localization study using cell- and pathogen-specific markers was performed. To detect Leishmania spp. a 5.8S ribosomal RNA (rRNA) parasite-specific sequence was used for in-situ hybridization and Mac387 was used as a macrophage marker for immunohistochemistry. Leishmania spp. rRNA was detected inside Mac387(+) macrophages and within the cytoplasm of some neoplastic cells. DNA isolation and polymerase chain reaction using specific primers and sequencing analysis identified the organism as Leishmania infantum (syn. Leishmania chagasi). This is the first report describing infection of tumour cells by L. infantum in a genital TVT from an asymptomatic bitch. Transplantation of Leishmania-laden neoplastic cells could represent an alternative route of venereal transmission of leishmaniasis among dogs.

Peripheral primitive neuroectodermal tumour in a dog.

A 1-year-old German shepherd dog was presented with paraparesis quickly progressing to paraplegia. Magnetic resonance imaging revealed a large mass beneath the thoracolumbar vertebral column infiltrating the spinal canal and resulting in severe extradural compression of the spinal cord. Microscopically, this comprised a cell-rich unencapsulated tumour supported by fine bands of a fibrovascular stroma and occasionally forming primitive rosettes. Immunohistochemistry showed the tumour cells to express synaptophysin and neuron-specific enolase. Ultrastructurally, the neoplastic cells had low to moderate numbers of intracytoplasmic neurosecretory granules. A peripheral primitive neuroectodermal tumour was diagnosed. This is a rare embryonal tumour of neural origin that may have arisen from adrenal medulla, autonomic ganglia or peripheral nerves.

Systemic adenovirus infection in Bearded Dragons (Pogona vitticeps): histological, ultrastructural and molecular findings.

Three Inland Bearded Dragons (Pogona vitticeps) from two breeding groups were humanely destroyed following a period of anorexia. Two of the animals were 8-months old and related and one animal was approximately 2-weeks old. Necropsy examination revealed poor bodily condition but no other gross abnormalities. Microscopically there was non-suppurative hepatitis and interstitial nephritis. Multiple large, amphophilic, intranuclear inclusion bodies were present within hepatocytes and epithelial cells of the bile ducts, renal tubules, small and large intestinal mucosa, pancreatic acini and oral mucous membranes. Transmission electron microscopy (TEM) demonstrated that the inclusions comprised viral particles with morphology consistent with an adenovirus. A fragment of the adenoviral polymerase gene was amplified, sequenced and compared with other reptilian adenoviral sequences.