Ethmoid Turbinates Research Articles

Dissecting the role of the HA1-226 leucine residue in the fitness and airborne transmission of an A(H9N2) avian influenza virus.

Although the capacity for human-like receptor binding is a key prerequisite for non-human origin influenza A virus (IAV) to become airborne transmissible in mammalian hosts, the underlying molecular basis is not well understood. In this study, we investigated a naturally occurring substitution (leucine to glutamine) at residue 226 in the HA of an avian-origin A(H9N2) virus and assessed the impact on virus replication and airborne transmission in the ferret model. We demonstrate that the enhanced airborne transmission associated with the HA1-L226 virus was mainly due to the increased infectivity of the virus. Interestingly, we found that, unlike most sites in the ferret respiratory tract, ferret ethmoid turbinate lined with olfactory epithelium favors replication of the AL/39-HA1-L226Q virus, suggesting that this site may serve as a unique niche for IAV with avian-like receptor binding specificity to potentially allow the virus to spread to extrapulmonary tissues and to facilitate adaptation of the virus to human hosts.

Differences in normal nasal computed tomography findings in different dog breeds

Background: Computed tomography (CT) is the gold standard for diagnosing canine nasal diseases. However, it cannot easily detect minor abnormalities in inflammatory diseases because they are not accompanied by obvious morphological changes. Aim: The present study aimed to compare the differences in normal CT findings of turbinate structure and mucosa between breeds in order to establish criteria for CT diagnosis of inflammatory diseases of the nasal cavity. Methods: CT data from 77 dogs of five breeds without nasal diseases were retrospectively studied. The nasal air percentage, which reflects the volume of the nasal turbinate structure and mucosa, was measured. The nasal turbinate mucosa was measured for contrast enhancement reflecting blood flow. Measurements were performed in the ventral and ethmoid turbinate regions. Comparisons were made between breeds and sections. Results: The air percentage in the ventral and ethmoid turbinate regions was significantly different between breeds. Contrast enhancement was significantly different between breeds only in the ethmoid turbinate. Moreover, different breeds had different correlations between body weight, age, nose length, and air percentage. Conclusion: In this study, reference values for normal CT findings of the nasal structure and mucosa were obtained, taking into account the breed, measurement section, and patient factors. The results showed that the volume of the turbinate structure and contrast enhancement of nasal mucosa differed depending on the breed. The measured values also differed depending on the cross-sections and patient factors.

Domestic cat nose functions as a highly efficient coiled parallel gas chromatograph.

The peripheral structures of mammalian sensory organs often serve to support their functionality, such as alignment of hair cells to the mechanical properties of the inner ear. Here, we examined the structure-function relationship for mammalian olfaction by creating an anatomically accurate computational nasal model for the domestic cat (Felis catus) based on high resolution microCT and sequential histological sections. Our results showed a distinct separation of respiratory and olfactory flow regimes, featuring a high-speed dorsal medial stream that increases odor delivery speed and efficiency to the ethmoid olfactory region without compromising the filtration and conditioning purpose of the nose. These results corroborated previous findings in other mammalian species, which implicates a common theme to deal with the physical size limitation of the head that confines the nasal airway from increasing in length infinitely as a straight tube. We thus hypothesized that these ethmoid olfactory channels function as parallel coiled chromatograph channels, and further showed that the theoretical plate number, a widely-used indicator of gas chromatograph efficiency, is more than 100 times higher in the cat nose than an "amphibian-like" straight channel fitting the similar skull space, at restful breathing state. The parallel feature also reduces airflow speed within each coil, which is critical to achieve the high plate number, while feeding collectively from the high-speed dorsal medial stream so that total odor sampling speed is not sacrificed. The occurrence of ethmoid turbinates is an important step in the evolution of mammalian species that correlates to their expansive olfactory function and brain development. Our findings reveal novel mechanisms on how such structure may facilitate better olfactory performance, furthering our understanding of the successful adaptation of mammalian species, including F. catus, a popular pet, to diverse environments.

Strategies of vascularization of the ethmoid labyrinth in selected even-toed ungulates (Artiodactyla) and carnivores (Carnivora).

The anatomy of the nasal cavity and its structures, as well as other elements building a scaffold for olfactory organs, differs significantly among various groups of mammals. Understanding anatomical conditions of quality of olfaction are being studied worldwide and is a complex problem. Among many studies regarding bone and epithelial structures of turbinates and connected anatomical structures, few studies describe the vascularization of turbinates. Ethmoid turbinates are above all covered in olfactory epithelium containing branched axons that receive olfactory stimuli and as olfactory nerves penetrate the cribriform lamina of the ethmoid bone conveying information from smell receptors to the brain. Differences in vascularization of the cribriform plate and turbinates may add crucial information complementing studies regarding the olfactory organ's bone and soft tissue structures. In the study, we describe the vascularization of the cribriform plate of the ethmoid bone of 54 Artiodactyla and Carnivora.

Technique of flat-mount immunostaining for mapping the olfactory epithelium and counting the olfactory sensory neurons.

The pathophysiology underlying olfactory dysfunction is still poorly understood, and more efficient biomolecular tools are necessary to explore this aspect. Immunohistochemistry (IHC) on cross sections is one of the major tools to study the olfactory epithelium (OE), but does not allow reliable counting of olfactory sensory neurons (OSNs) or cartography of the OE. In this study, we want to present an easy immunostaining technique to compensate for these defects of IHC. Using the rat model, we first validated and pre-screened the key OSN markers by IHC on cross sections of the OE. Tuj-1, OMP, DCX, PGP9.5, and N-cadherin were selected for immunostaining on flat-mounted OE because of their staining of OSN dendrites. A simple technique for immunostaining on flat-mounted septal OE was developed: fixation of the isolated septum mucosa in 0.5% paraformaldehyde (PFA) preceded by pretreatment of the rat head in 1% PFA for 1 hour. This technique allowed us to correctly reveal the olfactory areas using all the 5 selected markers on septum mucosa. By combining the mature OSN marker (OMP) and an immature OSN marker (Tuj-1), we quantified the mature (OMP+, Tuj-1-), immature (OMP-, Tuj-1+), transitory (OMP+, Tuj-1+) and total OSN density on septal OE. They were respectively 42080 ± 11820, 49384 ± 7134, 14448 ± 5865 and 105912 ± 13899 cells per mm2 (mean ± SD). Finally, the same immunostaining technique described above was performed with Tuj-1 for OE cartography on ethmoid turbinates without flat-mount.

Clinical and mycological investigations of post-COVID-19 acute invasive fungal sinusitis.

An increased incidence of acute invasive fungal sinusitis associated with the recent COVID-19 pandemic has been observed, which is considered a public health concern. This study aims to detect the incidence, risk factors, causative agents, clinical presentations, outcomes, and susceptibility rate of various antifungals. In this cross-sectional cohort study, a total of 30 patients showing acute invasive fungal rhinosinusitis following a COVID-19 infection were investigated. Histopathological biopsies, culture identification, and molecular confirmation of the causative agents were conducted. The demographic data, risk factors, clinical presentations, treatment regimen and its outcomes, and efficacy of antifungals were listed and analyzed. A total of 30 cases with a mean age of 59.6 ± 11.9 years were included. Diabetes mellitus was the most recorded comorbidity with a rate of 86.7%, whereas most of the patients received corticosteroids. The mycological examination confirmed the existence of Mucor (Rhizopus oryzae) and Aspergillus (Aspergillus niger) in 96.7% and 3.3% of the cases, respectively. Various stages of sinonasal involvement (ethmoid, maxillary, sphenoid, and inferior turbinate) represented 100%, 83.3%, 66.7%, and 86.7% of the cases, respectively. Headache and facial pain, ophthalmoplegia, visual loss, and blindness represented 100%, 66.7%, 90%, and 53.3% of the cases, respectively. All the cases were simultaneously treated with surgical debridement and amphotericin B. Moreover, R. oryzae was susceptible to it, whereas A. niger was sensitive to voriconazole, resulting in a survival rate of 86.7% (26/30). The R. oryzae and A. niger isolates were proven to be sensitive to acetic acid, ethyl alcohol, formalin, and isopropyl alcohol. In patients with COVID-19, the diagnosis of acute invasive fungal sinusitis and prompt treatment with antifungal medicine and surgical debridement are important in achieving better outcomes and survival rates. 4.

Enzootic nasal adenocarcinoma in sheep: An update

Enzootic nasal adenocarcinoma of sheep (ENAS) is a contagious tumor of the ethmoid turbinate mucosa. The disease occurs naturally in all continents except Australia and New Zealand. Similar disease has been described in goats. ENAS is aetiologically associated with enzootic nasal tumor virus 1 (ENTV-1) a type Beta retrovirus and closely related to jaagsiekte sheep retrovirus (JSRV) and enzootic nasal adenocarcinoma virus of goats (ENTV-2). Clinical signs include continuous nasal discharge, respiratory distress, exophtalmus and skull deformations. The tumors have been classified histologically as low grade adenocarcinoma. ENTV-1 can be demonstrated in tumors by immunohistochemistry using several antisera developed against JSRV antigens which cross-react with ENTV-1 ones. ENTV-1 shares a oncogenic mechanisms with JSRV and ENTV-2 and active replication of the virus is required because oncogenic proprieties are associated with env gene products. Information about immune reactions in relation to ENTV-1 is scarce and controversial. Some early studies indicated absence of immune reaction although more recent studies have detected the presence of neutralizing antibodies in sheep with tumors and in contact sheep. However, the sensitivity and specificity of these tests are very low to be used in field studies. Several specific PRC techniques are available to detect viral genome in tissues and tumors. ENTV-1 can be detected in nasal secretion but is rarely found out of the tumor. The utility of PCR tests in control or eradication plans is discussed.

First detection and genotypic analysis of goat enzootic nasal tumor virus 2 in Chongqing, China.

Enzootic nasal adenocarcinoma (ENA) of goats, characterized by transformation of epithelial cells of the ethmoid turbinates, is caused by enzootic nasal tumor virus 2 (ENTV-2). ENTV-2 belongs to the genus Betaretrovirus and has extended its distribution globally with a high prevalence; however, the genetic diversity and genotypic distribution for ENTV-2 have not been analyzed systematically due to the limited availability of sequence data. In this study, an infection by ENTV-2 was detected by RT-PCR in Chongqing in July 2018, and the complete sequence of one strain (CQ1) was determined. Phylogenetic analysis indicated a high degree of genetic heterogeneity among ENTV-2 sequences, with the existence of two main lineages. Lineage 1 and 2 were composed of ENTV-2 from China and the UK, respectively. Although CQ1 was closely related to recent ENTV-2 strains collected in the neighboring provinces of Chongqing (Shaanxi and Sichuan), it formed a separate sublineage of lineage 1 (sublineage 1.3). This report will enhance our understanding of the epidemiology of ENTV-2 in China.

Clinical and pathological findings of enzootic nasal adenocarcinoma of goat

The enzootic nasal tumor (ENT), a contagious tumor, is raised from the secretory epithelial cells of the ethmoid turbinate in animal which is caused by ENT virus type (ENTV) 2. The aim of this study is to investigate the clinical, radiological, and histopathological features of ENT or nasal adenocarcinoma in Lori-Bakhtiari breeds of goat. The affected goats showed respiratory nasal problems, continuous nasal exudate, and death resulted from progressive respiratory distress and anorexia. Dorsomedial radiographs of the skull region showed the mass in the right caudal paranasal sinus region deformation of bone in the near ethmoidal part. At necropsy, after dissection of the cranium through sagittal dorsomedial section, the presences of large unilateral tumor sessile masses with white, shiny, and soft like a gelatin form appearances were found. Acinar and papillary patterns were the most common histopathological finding in proliferated glands. The neoplastic cells were cuboidal or columnar with round or oval nuclei with very low mitotic index. This type of carcinoma originates from the serous gland cells in ethmoidal turbinate.

P.1.g.032 - The application of TCM to the treatment of psychiatry diseases: in vitro anti-oxidation and anti-inflammatory effect of Free and Easy Wanderer

Following inhalation, manganese travels along the olfactory nerve from the olfactory epithelium (OE) to the olfactory bulb (OB). Occupational exposure to inhaled manganese is associated with changes in olfactory function. This pilot study evaluated two related hypotheses: (a) intranasal manganese administration increases OE and OB manganese concentrations; and (b) intranasal manganese exposure impairs performance of previously trained rats on a go-no-go olfactory discrimination (OD) task. Male Fischer 344 rats were trained to either lever press (“go”) in response to a positive conditioned stimulus (CS+: vanillin) or to do nothing (“no go”) when a negative conditioned stimulus (CS−: amyl acetate) was present. Following odor training, rats were randomly assigned to either a manganese (200 mM MnCl2) or 0.9% saline treatment group (n = 4–5 rats/group). Administration of either saline or manganese was performed on isoflurane-anesthetized rats as 40 μL bilateral intranasal instillations. Rats were retested 48 h later using the vanillin/amyl acetate OD task, then euthanized, followed by collection of the OE and OB. Manganese concentrations in tissue samples were analyzed by ICP-MS. An additional cohort of rats (n = 3–4/group) was instilled similarly with saline or manganese and nasal and OB pathology assessed 48 h later. Manganese-exposed rats had increased manganese levels in both the OE and OB and decreased performance in the OD task when compared with control animals. Histopathological evaluation of the caudal nasal cavity showed moderate, acute to subacute suppurative inflammation of the olfactory epithelium and submucosa of the ethmoid turbinates and mild suppurative exudate in the nasal sinuses in animals given manganese. No histologic changes were evident in the OB. The nasal instillation and OD procedures developed in this study are useful methods to assess manganese – induced olfactory deficits.

Olfactory toxicity in rats following manganese chloride nasal instillation: A pilot study

Following inhalation, manganese travels along the olfactory nerve from the olfactory epithelium (OE) to the olfactory bulb (OB). Occupational exposure to inhaled manganese is associated with changes in olfactory function. This pilot study evaluated two related hypotheses: (a) intranasal manganese administration increases OE and OB manganese concentrations; and (b) intranasal manganese exposure impairs performance of previously trained rats on a go-no-go olfactory discrimination (OD) task. Male Fischer 344 rats were trained to either lever press (“go”) in response to a positive conditioned stimulus (CS+: vanillin) or to do nothing (“no go”) when a negative conditioned stimulus (CS−: amyl acetate) was present. Following odor training, rats were randomly assigned to either a manganese (200mM MnCl2) or 0.9% saline treatment group (n=4–5 rats/group). Administration of either saline or manganese was performed on isoflurane-anesthetized rats as 40μL bilateral intranasal instillations. Rats were retested 48h later using the vanillin/amyl acetate OD task, then euthanized, followed by collection of the OE and OB. Manganese concentrations in tissue samples were analyzed by ICP-MS. An additional cohort of rats (n=3–4/group) was instilled similarly with saline or manganese and nasal and OB pathology assessed 48h later. Manganese-exposed rats had increased manganese levels in both the OE and OB and decreased performance in the OD task when compared with control animals. Histopathological evaluation of the caudal nasal cavity showed moderate, acute to subacute suppurative inflammation of the olfactory epithelium and submucosa of the ethmoid turbinates and mild suppurative exudate in the nasal sinuses in animals given manganese. No histologic changes were evident in the OB. The nasal instillation and OD procedures developed in this study are useful methods to assess manganese – induced olfactory deficits.

Full-length genome sequence analysis of enzootic nasal tumor virus isolated from goats in China

BackgroundEnzootic nasal tumor virus (ENTV) is a betaretrovirus of sheep (ENTV-1) and goats (ENTV-2) associated with neoplastic transformation of epithelial cells of the ethmoid turbinate. Confirmation of the role of ENTV in the pathogenesis of enzootic nasal adenocarcinoma (ENA) has yet to be resolved due to the inability to culture the virus. Very little is known about the prevalence of this disease, particularly in China.MethodsTo evaluate the genetic diversity of ENTV-2 from Shaanxi province of China, the complete genome sequence of four isolates from Shaanxi province was determined by RT-PCR. These sequences were analyzed to evaluate their genetic relatedness with other small ruminant betaretroviruses. Phylogenetic analyses based on the gag gene and env gene were performed.ResultsThe ENTV-2-Shaanxi1 genome shared 97.0% sequence identity with ENTV-2-SC (accession number HM104174.1), and 89.6% sequence identity with the ENTV-2 sequences (accession number AY197548.1). ENTV-2 is closely related to the ENTV-1 and jaagsiekte retrovirus (JSRV). The main sequence differences between these viruses reside in LTR, two small regions of Gag, Orf-x, and the transmembrane (TM) region of Env. A stretch of 6 consecutive proline residues exists in VR1 of the ENTV-2-Shaanxi1 ~ 4 isolates. All the ENTV-2-Shaanxi isolates have the YXXM motif in the cytoplasmic tail of the Env. Phylogenetic analysis by nucleotide sequences showed that ENTV-2-Shaanxi1 ~ 4 isolates were closest related to two ENTV-2 isolates published in NCBI, especially with ENTV-2-SC strain.ConclusionsThis finding indicates that ENA most likely was introduced to Shaanxi province by the movement of contaminated goats from other areas in China. This study adds to understand the circulation, variation and distribution of ENTV-2, and may prove beneficial in future control or eradication programmes.

How to Expose the Entire Sella Floor With Minimal Manipulation During an Endoscopic Endonasal Transsphenoidal Approach.

A method of opening the posterior ethmoid air cells with minimal manipulation is important for adequate exposure of the sella floor and minimal nasal morbidity. Between February 2009 and August 2016, 373 patients with skull-base tumors underwent surgery via endoscopic endonasal transsphenoidal approach with the 2-nostrils/4-hands technique using this technique. A linear incision was made laterally toward one-third of the superior turbinate along the superior border of the sphenoid sinus ostium. Then, the superior turbinate mucosa was fully elevated to expose the superior turbinate bone. This allowed us to expose the entire sella floor and adjacent vital structures, such as the optic and carotid protuberances, medial and lateral opticocarotid recesses, planum sphenoidale, and clivus, leaving the superior turbinate and surrounding nasal mucosa intact. This technique could improve the manipulability of surgical instruments and increase the accessibility of the parasellar region. This approach better conserves the nasal mucosa, posterior ethmoid, and superior and supreme turbinates and more efficiently exposes skull-base tumors than traditional methods with pathology of the anterior cranial fossa and parasellar region. This technique also prevents the drilling procedure from damaging the surrounding nasal mucosa, including the exfoliated and laterally preserved posterior sphenoid mucosa.

Construction of a molecular clone of ovine enzootic nasal tumor virus.

BackgroundEnzootic nasal tumor virus (ENTV-1) is an ovine betaretrovirus that has been linked to enzootic nasal adenocarcinoma (ENA), a contagious tumor of the ethmoid turbinates of sheep. Transmission experiments performed using virus isolated from cell free nasal tumor homogenates suggest that ENTV-1 is the causative agent of ENA; however, this etiological relationship has not been conclusively proven due to the fact that the virus cannot be propagated in vitro nor is there an infectious molecular clone of the virus.MethodsHere we report construction of a molecular clone of ENTV-1 and demonstrate that transfection of this molecular clone into HEK 293T cells produces mature virus particles.ResultsAnalysis of recombinant virus particles derived from the initial molecular clone revealed a defect in the proteolytic processing of Gag; however, this defect could be corrected by co-expression of the Gag-Pro-Pol polyprotein from the highly related Jaagsiekte sheep retrovirus (JSRV) suggesting that the polyprotein cleavage sites in the ENTV-1 molecular clone were functional. Mutagenesis of the molecular clone to correct amino acid variants identified within the pro gene did not restore proteolytic processing; whereas deletion of one proline residue from a polyproline tract located in variable region 1 (VR1) of the matrix resulted in production of CA protein of the mature (cleaved) size strongly suggesting that normal virion morphogenesis and polyprotein cleavage took place. Finally, electron microscopy revealed the presence of spherical virus particles with an eccentric capsid and an average diameter of about 100 nm.ConclusionIn summary, we have constructed the first molecular clone of ENTV-1 from which mature virus particles can be produced. Future experiments using virus produced from this molecular clone can now be conducted to fulfill Koch’s postulates and demonstrate that ENTV-1 is necessary and sufficient to induce ENA in sheep.

Seroconversion of sheep experimentally infected with enzootic nasal tumor virus.

BackgroundEnzootic nasal tumor virus (ENTV-1) is an exogenous betaretrovirus of sheep that transforms epithelial cells lining the ethmoid turbinates leading to a disease called enzootic nasal adenocarcinoma (ENA). A unique feature of ENA is the apparent absence of a specific humoral immune response to the virus, despite the highly productive infection in nasal tumors. The sheep genome contains approximately 27 copies of endogenous ovine betaretroviral sequences (enJSRVs) and expression of enJSRVs in the ovine placenta and uterine endometrium throughout gestation is thought to induce immunological tolerance to exogenous ovine betaretroviruses, a factor that may influence the likelihood of exogenous ENTV infection and disease outcome. Nevertheless, we recently demonstrated the presence of neutralizing antibodies directed against the ENTV-1 envelope glycoprotein in sheep naturally exposed to ENTV-1.FindingsHere, we employed an ENTV-1 envelope glycoprotein surface subunit specific ELISA and a virus neutralization assay to monitor serum antibody responses to ENTV-1 in a group of lambs experimentally infected with ENTV-1 virus containing filtered ENA tumor homogenate. Seroconversion and development of neutralizing antibodies was detected in one of six experimentally infected lambs.ConclusionsOur results demonstrate that sheep can respond immunologically and seroconvert following ENTV-1 infection suggesting that anti-viral immune responses may play a role in the development of ENA.

Nasal Adenocarcinoma in a Horse with Metastasis to Lung, Liver, and Bone and Review of Metastasis in Nine Horses with Sinonasal Tumors

Sinonasal neoplasia metastasizing to distant organs is rare in horses. This case report describes the clinical and imaging findings of a horse with sinonasal neoplasia, which had metastasized to the lung, liver, and humerus. Additionally, the prevalence of sinonasal neoplasia and their incidence of distant metastasis among horses that presented to the Oregon State University Veterinary Teaching Hospital (OSU-VTH) were estimated. Of 5,558 equine patients who presented to the OSU-VTH in the last nine years, 1.4% were diagnosed with sinonasal disease and 10.3% of these cases had sinonasal neoplasia with only one having confirmed distant metastasis. This case was an eleven-year-old quarter horse which was evaluated due to a history of a right forelimb lameness of three weeks duration. Two and a half months later he presented again, this time for unilateral epistaxis and persistent right forelimb lameness. Radiography of the right elbow noted an increasingly irregular, periosteal response and osteolytic lesion of the right distal humeral condyle. At the time of the second presentation, nasosinal endoscopy identified a lobulated mass in the region of the ethmoid turbinates. Histopathology of this mass revealed an adenocarcinoma of nasal origin with metastasis to the lung, liver, and right humerus.

Histological and lectin histochemical studies on the olfactory mucosae of the Korean roe deer, Capreolus pygargus.

The morphological features of the olfactory mucosae of Korean roe deer, Capreolus pygargus, were histologically studied using the ethmoid turbinates containing the olfactory mucosae from six roe deer (male, 2-3 years old). The ethmoid turbinates were embedded in paraffin, and histochemically evaluated in terms of the mucosal characteristics. Lectin histochemistry was performed to investigate the carbohydrate-binding specificity on the olfactory mucosa. Lectins, including Triticum vulgaris wheat germ agglutinin (WGA), Ulex europaeus agglutinin I (UEA-I), and soybean agglutinin (SBA) were used for the N-acetylglucosamine, fucose and N-acetylgalactosamine carbohydrate groups, respectively. Histologically, the olfactory mucosa, positioned mainly in the caudal roof of the nasal cavity, consisted of the olfactory epithelium and the lamina propria. The olfactory epithelium consisted of protein gene product (PGP) 9.5-positive olfactory receptor cells, galectin-3-positive supporting cells and basal cells. Bowman's glands in the lamina propria were stained by both the periodic acid Schiff reagent and alcian blue (pH 2.5). Two types of lectin, WGA and SBA, were labeled in free border, receptor cells, supporting cells and Bowman's glands, with the exception of basal cells, while UEA-I was labeled in free border, supporting cells and Bowman's glands, but not in receptor cells and basal cells, suggesting that carbohydrate terminals on the olfactory mucosae of roe deer vary depending on cell type. This is the first morphological study of the olfactory mucosa of the Korean roe deer to evaluate carbohydrate terminals in the olfactory mucosae.

Effect of brachycephalic, mesaticephalic, and dolichocephalic head conformations on olfactory bulb angle and orientation in dogs as determined by use of in vivo magnetic resonance imaging

To determine the effect of head conformation (brachycephalic, mesaticephalic, and dolichocephalic) on olfactory bulb angle and orientation in dogs by use of in vivo MRI. 40 client-owned dogs undergoing MRI for diagnosis of conditions that did not affect skull conformation or olfactory bulb anatomy. For each dog, 2 head conformation indices were calculated. Olfactory bulb angle and an index of olfactory bulb orientation relative to the rest of the CNS were determined by use of measurements obtained from sagittal T2-weighted MRI images. A significant negative correlation was found between olfactory bulb angle and values of both head conformation indices. Ventral orientation of olfactory bulbs was significantly correlated with high head conformation index values (ie, brachycephalic head conformation). Low olfactory bulb angles and ventral olfactory bulb orientations were associated with brachycephalia. Positioning of the olfactory bulbs, cribriform plate, and ethmoid turbinates was related. Indices of olfactory bulb angle and orientation may be useful for identification of dogs with extremely brachycephalic head conformations. Such information may be used by breeders to reduce the incidence or severity of brachycephalic-associated diseases.

Enzootic Nasal Tumour of Goats in Greece

ENZOOTIC NASAL TUMOUR OF GOATS IN GREECE P. Loukopoulos, N.D. Giadinis, V. Psychas, C.I. Dovas and E. Kaldrymidou Faculty of Veterinary Medicine, Aristotle University, Greece Introduction: The enzootic nasal tumour (ENT) of goats arises from secretory epithelial cells of the ethmoid turbinate and follows infection by ENTV-2, an exogenous retrovirus. The geographical distribution of the disease is believed to be wide, but this has not been studied comprehensively. Materials and Methods: Intranasal tumours of goats that were included in the study were retrieved from the archives or were recruited as part of an ongoing prospective study. The tumours were examined grossly and microscopically and a selected number of tumour samples was analyzed by PCR and sequencing. Results: Fifty-four intranasal tumours were examined, the first of which was initially examined in 1984. Although no metastases were observed, a small number of cases were locally aggressive. Histologically, most cases were low-grade adenocarcinomas. The cases originated from four geographical regions in Greece (Thrace, Macedonia, Thessaly and central Greece). PCR detected ENTV-2 proviral DNA within the tumours examined. Sequencing and phylogenetic analysis demonstrated clustering of these isolates with the ENTV-2 prototypes in a branch distinct from ENTV-1, JSRV and SERV representatives. Conclusions: ENT of goats is present and appears to have widespread geographical distribution in Greece. Further examination and monitoring of the disease status is warranted. P1

Full-length genome sequence analysis of enzootic nasal tumor virus reveals an unusually high degree of genetic stability

Enzootic nasal tumor virus (ENTV) is a betaretrovirus of sheep (ENTV-1) and goats (ENTV-2) associated with neoplastic transformation of epithelial cells of the ethmoid turbinate. Confirmation of the role of ENTV in the pathogenesis of enzootic nasal adenocarcinoma (ENA) has yet to be resolved due to the lack of an infectious molecular clone and the inability to culture the virus. Very little is known about the prevalence of this disease, particularly in North America, and only one full-length sequence is available for each of ENTV-1 and ENTV-2. In order to understand the molecular evolution of ENTV-1, the full-length genome sequence of ten ENTV-1 proviruses derived from clinical samples of ENA isolated from conventionally reared sheep in Canada and the United States was determined. The North American ENTV-1 (ENTV-1 NA) genomes shared greater than 96% sequence identity with the European ENTV-1 sequence (ENTV-1 EU). Most of the amino acid differences were found in Orf-x, which in the corresponding ENTV-1 EU genome is truncated by 44 amino acids. Apart from Orf-x, the long terminal repeat (LTR) is where the majority of differences between ENTV-1 NA and ENTV-1 EU reside. Overall, there was an unusually high degree of amino acid conservation among the isolates suggesting that ENTV-1 is under stabilizing selection and K a/ K s ratios calculated for each of the viral genes support this hypothesis. The unusually high degree of genetic stability of the ENTV-1 genome enabled us to develop a hemi-nested PCR assay for detection of ENTV-1 in clinical samples. Additionally, multiple nasal tumor cell clones were established and while most had lost the provirus by passage 5; one polyclonal line retained the provirus and attempts are being made to culture these cells. These tumor cells, the first of their kind, may provide a system for studying ENTV-1 in vitro. This work represents an important step in the study of ENTV and sets the foundation for the construction of an infectious molecular clone of ENTV-1.