Evaluation of the Local Immune Response to Hydatid Cysts in Sheep Liver

In order to characterize the inflammatory phenotype of livers of sheep naturally infected by cystic echinococcosis, 100 sheep livers have been macroscopically assessed for the presence of hydatid cysts and sampled for histopathological and molecular analysis. According to gross and microscopic examination, livers were subsequently classified into three groups: normal liver (Group A), liver with the presence of fertile hydatid cysts (Group B), and liver with the presence of sterile hydatid cysts (Group C). Immunohistochemical analyses were accomplished using primary antibodies anti-Iba1, anti-CD3, anti-CD20, anti-TGF-β, and anti-MMP9. Finally, real-time PCR was performed in order to estimate the concentration levels of tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), interleukin (IL)-12, IL-10, and TGF-β. Immunohistochemical analysis showed a diffuse immunolabelling of mononuclear cells for Iba-1 and TGF-β and a higher amount of CD20+ B cells compared to CD3+ T cells in both Groups B and C. The expression levels of Th-1-like immune cytokines TNF-α, INF-γ, and IL-12 did not show significant statistical differences. However, we found a significant increase in expression levels of Th-2 immune cytokines TGF-β and IL-10 in Groups B and C compared to Group A. Taken together, our findings suggest that macrophages have a predominant role in the local immune response to cystic echinococcosis. Moreover, we can speculate that Th2 immunity may be dominant, corroborating the idea that B cells are decisively essential in the control of the immune response during parasitic infection and that the immunomodulatory role of IL-10 and TGF-β may ensure the persistence of the parasite within the host.

Identification of vacuolar autophagic aggregates in the skeletal muscles of inbred C57BL/6NCrl mice

A comprehensive pathological analysis of inbred strains is essential to define strain-specific spontaneous lesions and to understand whether a specific phenotype results from experimental intervention or reflects a naturally occurring disease. This study aimed to report and describe a novel condition affecting the skeletal muscles of an inbred C57BL/6NCrl mouse colony characterised by large sarcoplasmic vacuoles in the muscle fibres of male mice in the subsarcolemmal spaces and the intermyofibrillary network. There was no muscle weakness, loss of ambulation or cardiac/respiratory involvement. Post-mortem evaluation and histological analysis excluded the presence of pathological accumulations or lesions in other tissues and organs. Changes were seen in fibre size, with many hypotrophic and some slightly hypertrophic fibres. Histological, immunohistochemical and molecular analyses of the vacuolar content revealed dysregulation of the autophagy machinery while ruling out a morphologically similar condition marked by the accumulation of tubular aggregates.

Reproducibility and Feasibility of Classification and National Guidelines for Histological Diagnosis of Canine Mammary Gland Tumours: A Multi-Institutional Ring Study

Simple Summary

Tumours of the mammary gland are common in humans, as in canine species. They are very heterogenous with numerous morphological variants and different biologic behaviours. In the last few decades, several efforts have been made to classify these tumours histologically and establish the level of malignancy by using histologic grading systems. However, reproducibility and diagnostic agreement of such classification and grading have been only rarely assessed. In this study, we tested the variability in diagnoses performed by 15 pathologists using the same classification and grading system. Prior to the study, pathologists agreed on guidelines regarding how to apply these systems. Pathologists worked blindly on 36 digital histologic slides of canine mammary tumours. The agreement was statistically analysed using Cohen’s kappa coefficient that, when equal to 1, indicates perfect agreement. The overall agreement in the identification of hyperplastic-dysplastic/benign/malignant lesions was substantial (kappa 0.76), while outcomes on morphological classification had only a moderate agreement (k = 0.54). Tumour grade assigned by pathologists was the least concordant and kappa could not be calculated. Although promising, the results underline that each diagnostic/grading system should be assessed and optimized for standardization and high diagnostic agreement.

Abstract

Histological diagnosis of Canine Mammary Tumours (CMTs) provides the basis for proper treatment and follow-up. Nowadays, its accuracy is poorly understood and variable interpretation of histological criteria leads to a lack of standardisation and impossibility to compare studies. This study aimed to quantify the reproducibility of histological diagnosis and grading in CMTs. A blinded ring test on 36 CMTs was performed by 15 veterinary pathologists with different levels of education, after discussion of critical points on the Davis-Thompson Foundation Classification and providing consensus guidelines. Kappa statistics were used to compare the interobserver variability. The overall concordance rate of diagnostic interpretations of WP on identification of hyperplasia-dysplasia/benign/malignant lesions showed a substantial agreement (average k ranging from 0.66 to 0.82, with a k-combined of 0.76). Instead, outcomes on ICD-O-3.2 morphological code /diagnosis of histotype had only a moderate agreement (average k ranging from 0.44 and 0.64, with a k-combined of 0.54). The results demonstrated that standardised classification and consensus guidelines can produce moderate to substantial agreement; however, further efforts are needed to increase this agreement in distinguishing benign versus malignant lesions and in histological grading.

Canine and feline in situ mammary carcinoma: A comparative review

Carcinoma in situ of the breast is a well-known entity in humans. In veterinary medicine, particularly in canine and feline mammary literature, there is no agreement whether the term in situ should be used to indicate a specific carcinoma histotype or the noninvasive status of a carcinoma of any histotype. Moreover, in the most recent histologic classification of mammary tumors published by the Davis-Thompson Foundation, it is suggested to abandon the term carcinoma in situ given the lack of standardized criteria defining this entity, replacing it with epitheliosis or ductal/lobular hyperplasia with severe atypia. This publication presents a critical review of the term in situ in human and veterinary medicine considering the evolution of the term over the years and its heterogeneous use by different authors, including variations in immunohistochemical markers for classification. This review aims to point out the lack of uniformity in the nomenclature and classification issues in veterinary medicine regarding the use of the term in situ, laying the ground for a process of standardization in future publications.

Leishmania spp.-Infected Dogs Have Circulating Anti-Skeletal Muscle Autoantibodies Recognizing SERCA1

Leishmania spp. infection is associated with an inflammatory myopathy (IM) in dogs. The pathomechanism underlying this disorder is still elusive, however, the pattern of cellular infiltration and MHC I and II upregulation indicate an immune-mediated myositis. This study aimed to investigate the presence of autoantibodies targeting the skeletal muscle in sera of leishmania-infected dogs and individuate the major autoantigen. We tested sera from 35 leishmania-infected dogs and sera from 10 negative controls for the presence of circulating autoantibodies with indirect immunofluorescence. Immunoblot and mass spectrometry were used to identify the main target autoantigen. Immunocolocalization and immunoblot on immunoprecipitated muscle proteins were performed to confirm the individuated major autoantigen. We identified circulating autoantibodies that recognize skeletal muscle antigen(s) in sera of leishmania-infected dogs. The major antigen was identified as the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 1 (SERCA1). We also found that canine SERCA1 presents several identical traits to the calcium-translocating P-type ATPase of Leishmania infantum. In the present study, we defined circulating anti-SERCA1 autoantibodies as part of the pathogenesis of the leishmania-associated IM in dogs. Based on our data, we hypothesize that antigen mimicry is the mechanism underlying the production of these autoantibodies in leishmania-infected dogs.

Pathologic characterization of white striping myopathy in broiler chickens

White striping (WS) is an emerging myopathy of broiler chickens characterized by white striation of muscle. Despite the recent advances, the pathomechanism underlying the WS remains elusive. The aim of this study was to characterize morphological and molecular features of WS in broiler chickens. 50 pectoralis muscles were collected from 55 days old ROSS 308 broiler chickens with a mean weight of 3.5 kg. Samples were snap frozen and analyzed by histopathology, immunohistochemistry, and immunofluorescence. Real-time-PCR was used to evaluate the expression of different cytokines. Histological lesions were observed in all examined animals, both with and without macroscopic evidence of WS. WS muscles showed endomysial and perivascular inflammatory infiltrates of macrophages and cluster of differentiation (CD)8-positive T lymphocytes with severe myofiber atrophy, necrosis, fibrosis and replacement by adipose tissue. There was diffuse sarcoplasmic and sarcolemmal overexpression of the major histocompatibility complex class I (MHC I). The severity of the histologic lesions was positively correlated with the macroscopic degree of white striations. IL-6, IL-17 and lipopolysaccharide-induced TNF-α factor (LITAF) were overexpressed in severe lesions of WS. The presence of the CD8/MHC I complexes, together with the higher expression of IL-6, IL-17 and LITAF in severe degree of WS, suggest that the immune response may be involved in the progression of this myopathy and can be consistent with a hypoxia-induced inflammatory myopathy. These results help to understand the pathomechanism of WS contributing to the reduction of economic losses and improving poultry welfare.

RNAScope in situ Hybridization as a Novel Technique for the Assessment of c-KIT mRNA Expression in Canine Mast Cell Tumor

RNA is considered as an indicator of the dynamic genetic expression changes in a cell. RNAScope is a commercially available in situ hybridization assay for the detection of RNA in formalin-fixed paraffin-embedded tissue. In this work, we describe the use of RNAScope as a sensitive and specific method for the evaluation of c-KIT messenger RNA (mRNA) in canine mast cell tumor. We investigated the expression of c-KIT mRNA with RNAscope in 60 canine mast cell tumors (MCTs), comparing it with the histological grade and KIT immunohistochemical expression patterns. Our results showed an overall good expression of c-KIT mRNA in neoplastic cells if compared with control probes. We also observed a statistically significant correlation between histological grade and c-KIT mRNA expression. No correlations were found between KIT protein immunohistochemical distribution pattern and c-KIT mRNA expression or histological grade. Our results provide a reference basis to better understand c-KIT mRNA expression in canine MCTs and strongly encourage further studies that may provide useful information about its potential and significant role as a prognostic and predictive biological marker for canine MCTs clinical outcome.

The correlation between cardiac and skeletal muscle pathology in animal models of idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) represent a heterogeneous group of disorders in which skeletal muscle is inappropriately targeted by the immune system. IIMs are characterized by inflammation of muscle and varying degrees of muscle dysfunction. Extra-muscular manifestations may involve heart, skin, joints, lungs, and gastrointestinal tract. Cardiovascular involvement is a feared event because is one of the leading causes of mortality in IIM patients. As the myocardium shares many features with the skeletal muscle, it is supposed that it can be affected by the same inflammatory processes, which take place during the different forms of IIMs. However, the full extent of this link and the mechanisms behind it are still not fully understood. Animal models have greatly improved our understanding of IIM pathomechanisms and have proven to be a useful tool for discovering therapeutic drug targets. Here we report the evidence of heart muscle involvement in different animal models of spontaneous IIMs, assuming a common autoimmune mechanism and presenting them as study models for human pathology.

Pneumoperitoneum Modifies Serum and Tissue CCL2-CCL5 Expression in Mice

Background and Objectives:

Laparoscopy is the preferred method when operating in the abdomen. In this study, we evaluated systemic and morphological peritoneal cytokine modifications (RANTES/CCL5 and MCP-1/CCL2) due to CO₂ pneumoperitoneum in rats.

Methods:

Twenty-five prepubertal Sprague-Dawley rats were randomized into three groups. Pneumoperitoneum lasting 30 minutes, was induced with a flow of 0.5 L/min, in two groups (S1 and S2, n = 20), at a P/CO₂ of 6 and 10 mm Hg, respectively. In the control group (C, n = 5), only anesthesia was carried out. All animals were sacrificed after 24 hours. The serum of the rats was collected for ELISA, and the levels of the cytokines RANTES and MCP-1 were investigated. An immunohistochemical analysis of RANTES and MCP-1 was performed on samples of the peritoneum, and the morphological evaluation was conducted with a blinded evaluation by two independent, experienced pathologists by using a grading system (0, 1+, 2+, 3+: no, faint, moderate, and strong reactivity, respectively).

Results:

RANTES mean levels were significantly different in the S1, S2, and C groups (70.3 ± 2.26, 58.23 ± 4.32, 29.66 ± 4.03, respectively, P = .0001). The levels of MCP-1 were 32.1 ± 1.63 in the S1 group, 27.0 ± 9.26 in the S2 group, and 16.4 ± 9.55 in the C group (P = .159). Normal control peritoneum showed little reactivity, whereas a moderate to strong cytoplasmic reaction to anti-CCL5/CCL2 antibodies was observed in mesothelial and inflammatory cells in the S1 and S2 groups.

Conclusion:

CO₂ pneumoperitoneum evokes an inflammatory response by modifying plasma RANTES levels and peritoneal CCL5/CCL2 expression.

Autophagy and NLRP3 inflammasome crosstalk in neuroinflammation in aged bovine brains

NLRP3 inflammasome is a multiprotein complex that can sense several stimuli such as autophagy dysregulation and increased reactive oxygen species production stimulating inflammation by priming the maturation of proinflammatory cytokines interleukin-1β and interleukin-18 in their active form. In the aging brain, these cytokines can mediate the innate immunity response priming microglial activation. Here, we describe the results of immunohistochemical and molecular analysis carried out on bovine brains. Our results support the hypothesis that the age-related impairment in cellular housekeeping mechanisms and the increased oxidative stress can trigger the inflammatory danger sensor NLRP3. Moreover, according to the recent scientific literature, we demonstrate the presence of an age-related proinflammatory environment in aged brains consisting in an upregulation of interleukin-1β, an increased microglial activation and increased NLRP3 expression. Finally, we suggest that bovine may potentially be a pivotal animal model for brain aging studies.

Muscular Sarcocystosis in Sheep Associated With Lymphoplasmacytic Myositis and Expression of Major Histocompatibility Complex Class I and II

Sarcocystosis is a protozoal disease affecting a wide range of animals. The aims of this study were to characterize the following in sheep: (1) the muscle pathology in Sarcocystis infection, (2) the inflammatory infiltrate and its relationship to severity of infection, and (3) immune markers expressed by parasitized muscle fibers and parasitic cysts. Skeletal muscle samples from 78 sheep slaughtered in southern Italy were snap frozen and analyzed by histopathology, immunohistochemistry, and immunofluorescence. Polymerase chain reaction (PCR) and sequencing were used for Sarcocystis species identification. All 40 muscle samples tested were PCR-positive for Sarcocystis tenella. Histologically, cysts were identified in 76/78 cases (97%), associated with an endomysial infiltrate of lymphocytes and plasma cells. The T cells were predominantly CD8+, with fewer CD4+ or CD79α+ cells. Eosinophils were absent. Notably, sarcolemmal immunopositivity for major histocompatibility complex (MHC) I and II was found in 76/78 cases (97%) and 75/78 cases (96%), respectively, both in samples with and in those without evident inflammatory infiltrate. The number of cysts was positively correlated with inflammation. In addition, MHC I was detected in 55/78 cyst walls (72%), and occasionally co-localized with the membrane-associated protein dystrophin. The findings suggest that muscle fibers respond to the presence of cysts by expression of MHC I and II. The possible role of MHC I and II in the inflammatory response and on the cyst wall is also discussed.

Long term breeding of the Lmna G609G progeric mouse: Characterization of homozygous and heterozygous models

The transgenic Lmna^G609G progeric mouse represents an outstanding animal model for studying the human Hutchinson-Gilford Progeria Syndrome (HGPS) caused by a mutation in the LMNA gene, coding for the nuclear envelope protein Lamin A/C, and, as an important, more general scope, for studying the complex process governing physiological aging in humans. Here we give a comprehensive description of the peculiarities related to the breeding of Lmna^G609G mice over a prolonged period of time, and of many features observed in a large colony for a 2-years period. We describe the breeding and housing conditions underlining the possible interference of the genetic background on the phenotype expression. This information represents a useful tool when planning and interpreting studies on the Lmna^G609G mouse model, complementing any specific data already reported in the literature about this model since its production. It is also particularly relevant for the heterozygous mouse, which mirrors the genotype of the human pathology however requires an extended time to manifest symptoms and to be carefully studied.

The T197A Knock-in Model of Cdkn1b Gene to Study the Effects of p27 Restoration In Vivo

The CDK inhibitor, p27^kip1, encoded by the Cdkn1b gene can negatively modulate cell proliferation. The control of p27 activity during the cell cycle is regulated at multiple levels, including transcription, translation, and protein stability. The last residue of p27 (threonine 198 in human, threonine 197 in mouse) is involved in the control of protein stability. We have generated a murine knock-in model (Cdkn1b ^T197A) in which threonine 197 is replaced by alanine, which renders p27 protein highly unstable due to a high rate of proteasomal degradation. Expectedly, Cdkn1b ^T197A/T197A mice present with increased body size and weight, organomegaly, and multiple organ hyperplasia, similar to what is observed in Cdkn1b ^KO/KO mice. We investigated the effects exerted by the restoration of normal levels of p27 protein in the tissue of Cdkn1b ^T197A/T197A mice. We found that proteasome inhibition with bortezomib rescues the hyperplasia induced by the lack of p27 expression in Cdkn1b ^T197A/T197A but not in Cdkn1b ^KO/KO mice. However, BAY 11-7082, a proteasome inhibitor that stabilizes IκB but not p27, fails to rescue hyperplasia in Cdkn1b ^T197A/T197A mice. Bortezomib increases p27 half-life and reduces the proliferation in MEFs derived from Cdkn1b ^T197A/T197A but not from Cdkn1b ^WT/WT mice, whereas BAY 11-7082 had no effect on the protein levels of p27 and on the proliferation rate of Cdkn1b ^T197A/T197A MEFs.The results presented here demonstrate that Cdkn1b ^T197A/T197A mice represent an attractive in vivo model to investigate whether the targeting of p27 degradation machinery might prove beneficial in the treatment of a variety of human proliferative disorders caused by increased turnover of p27 protein.

HMGA2 cooperates with either p27kip1 deficiency or Cdk4R24C mutation in pituitary tumorigenesis

We have previously reported a critical role of HMGA proteins in pituitary tumorigenesis since either the Hmga1 or Hmga2 gene overexpression/activation induces the development of mixed growth hormone/prolactin cell pituitary adenomas by activating the E2F transcription factor 1, and then enhancing the G1/S transition of the cell cycle. Consistently, amplification and overexpression of the HMGA2 gene was found in human pituitary prolactinomas. Since impairment of the cell cycle control represents a feature of experimental and human pituitary adenomas, we have investigated the possible synergism between the alterations of other cell cycle regulators, such as p27 deficiency or Cdk4^R24C mutation, with Hmga2 overexpression in pituitary tumorigenesis. Therefore, we crossed the Hmga2/T mice, overexpressing the truncated/active form of the Hmga2 gene, either with the knockout mice for p27^kip1, or with the knockin mice for the Cdk4^R24C mutation, both developing pituitary adenomas. Increased incidence and decreased latency in the development of pituitary lesions appeared in double mutant Hmga2/T;Cdk4^R24C mice, and increased features of invasiveness and atypia were observed in pituitary tumors of both Hmga2/T;p27-ko and Hmga2/T;Cdk4^R24C double mutant mice as compared with single mutant compounds. Interestingly, most of these mice develop pituitary adenomas with high Ki67 index, extrasellar expansion and brain tissue infiltration, representing good mouse models for human aggressive pituitary adenomas. Taken together, the results reported here indicate a cooperation between HMGA2 overexpression and either p27^kip1 or CDK4 impairment in promoting pituitary tumor development and progression.

Oncogene-induced senescence and its evasion in a mouse model of thyroid neoplasia

Here we describe a conditional doxycycline-dependent mouse model of RET/PTC3 (NCOA4-RET) oncogene-induced thyroid tumorigenesis. In these mice, after 10 days of doxycycline (dox) administration, RET/PTC3 expression induced mitogen activated protein kinase (MAPK) stimulation and a proliferative response which resulted in the formation of hyperplastic thyroid lesions. This was followed, after 2 months, by growth arrest accompanied by typical features of oncogene-induced senescence (OIS), including upregulation of p16INK4A and p21CIP, positivity at the Sudan black B, activation of the DNA damage response (DDR) markers γH2AX and pChk2 T68, and induction of p53 and p19ARF. After 5 months, about half of thyroid lesions escaped OIS and formed tumors that remained dependent on RET/PTC3 expression. This progression was accompanied by activation of AKT-FOXO1/3a pathway and increased serum TSH levels.

Inflammatory Myopathy in Horses With Chronic Piroplasmosis

Horses affected by chronic piroplasmosis may develop poor performance and muscle atrophy. Here we investigate the pathological and immunopathological aspects of myopathy occurring in chronic equine piroplasmosis. The study included 16 horses serologically positive for equine piroplasms presenting with clinical signs and supporting serum biochemical evidence of a myopathy. Skeletal muscle was evaluated by histopathology, immunohistochemistry, indirect immunofluorescence, and molecular detection of piroplasms and inflammatory cytokines in skeletal muscle. Histologic lesions included muscle fiber atrophy (100% of cases), degenerative changes (13/16, 81%), and perivascular perimysial and endomysial lymphocytic infiltrates (81% of cases). In 15 cases (94%), muscle fibers had strong immunostaining for major histocompatibility complex classes I and II. T lymphocyte populations were mainly CD3+, CD8+, and CD4+ in equal proportions, with a lower number of CD79α+ cells. The serum from affected horses was tested by indirect immunofluorescence for binding of IgG, IgM, or IgA to sections of normal equine muscle to detect circulating autoantibodies against muscle antigen(s). In all cases, distinct sarcolemmal staining was detected in sections incubated with serum from affected horses, in contrast to sections incubated with phosphate-buffered saline or equine control sera. Reverse transcription polymerase chain reaction (RT-PCR) testing of muscles from affected animals revealed a significant increase of interferon-γ, interleukin-12, and tumor necrosis factor-α gene expression compared to healthy controls. Theileria equi or Babesia caballi was not detected in samples of affected muscle by RT-PCR. Thus, inflammatory myopathy associated with equine piroplasmosis may involve an autoimmune pathogenesis with upregulation of inflammatory cytokines that may cause myofiber atrophy and degeneration.

Amyloid precursor protein, lipofuscin accumulation and expression of autophagy markers in aged bovine brain

Background

Autophagy is a highly regulated process involving the bulk degradation of cytoplasmic macromolecules and organelles in mammalian cells via the lysosomal system. Dysregulation of autophagy is implicated in the pathogenesis of many neurodegenerative diseases and integrity of the autophagosomal - lysosomal network appears to be critical in the progression of aging. Our aim was to survey the expression of autophagy markers and Amyloid precursor protein (APP) in aged bovine brains. For our study, we collected samples from the brain of old (aged 11–20 years) and young (aged 1–5 years) Podolic dairy cows. Formalin-fixed and paraffin embedded sections were stained with routine and special staining techniques. Primary antibodies for APP and autophagy markers such as Beclin-1 and LC3 were used to perform immunofluorescence and Western blot analysis.

Results

Histologically, the most consistent morphological finding was the age-related accumulation of intraneuronal lipofuscin. Furthermore, in aged bovine brains, immunofluorescence detected a strongly positive immunoreaction to APP and LC3. Beclin-1 immunoreaction was weak or absent. In young controls, the immunoreaction for Beclin-1 and LC3 was mild while the immunoreaction for APP was absent. Western blot analysis confirmed an increased APP expression and LC3-II/LC3-I ratio and a decreased expression of Beclin-1 in aged cows.

Conclusions

These data suggest that, in aged bovine, autophagy is significantly impaired if compared to young animals and they confirm that intraneuronal APP deposition increases with age.

Correlation of Nuclear Morphometric Features with Animal and Human World Health Organization International Histological Classifications of Canine Spontaneous Seminomas

The aim of this study was to correlate nuclear morphometric features with animal and human World Health Organization International Histological Classifications in canine seminomas. Twenty-three canine seminomas were classified, according to Animal World Health Organization International Histological Classification as intratubular, intratubular with signs of invasion, or diffuse and according to Human World Health Organization International Histological Classification criteria as spermatocytic and typical. The morphonuclear characteristics of tumors were quantitatively evaluated by means of digital cell image analyses of hematoxylin and eosin-stained nuclei. In particular, the mean nuclear area, mean nuclear perimeter, mean nuclear form factor, and their respective standard deviations were calculated. The relationship between the different variables and the tumor histologic types was assessed. On the basis of animal and human classification systems, statistically significant differences were observed only between intratubular seminomas with signs of invasion and the other two types and between spermatocytic and typical seminomas, respectively. In humans, it is well known that typical seminomas are more common and aggressive than spermatocytic ones. In our study, the canine seminomas classified as typical showed significantly larger and more variable nuclear area and perimeter than spermatocytic seminomas. These results support the opinion that most canine seminomas correspond to human spermatocytic seminomas and could explain the benign behavior of canine seminomas, which derive from a more differentiated type of germ cell.

Myopathy with Central Cores in a Foal

Central core disease is a nonprogressive or slowly progressive congenital myopathy with a variable degree of hypotonia and axial and proximal muscle weakness that is histologically characterized by areas devoid of oxidative enzyme activity, resulting from an absence or low numbers of mitochondria in these regions (central core). A 10-month-old, male, pony foal was examined because of stiff gait, marked contractures of the distal portion of the limbs, flexion deformities of the hooves, and moderate hypotonia that had been present from birth. The foal had increased creatine kinase (282 U/ liter; reference interval 10-135 U/liter), lactate dehydrogenase (1,188 U/liter; reference interval 150–450 U/liter), and aspartate transaminase (377 U/liter; reference interval <290 U/liter) activities, suggesting muscle disease. Muscle biopsy was performed. In cytochrome oxidase-, succinate dehydrogenase-, and reduced nicotinamide adenine dinucleotide tetrazolium reductase-reacted sections, the dominant morphologic feature was the absence of oxidative enzyme activity in the cores. By use of immunohistochemical technique with a monoclonal antibody against desmin, the cores were clearly delineated and a desmin network was present within the cores. Ultrastructurally, the core areas were characterized by preserved sarcomeres with irregular Z-lines, with some streaming or zigzag appearance and abnormal sarcoplasmic reticulum profiles and T-tubules. Lack of mitochrondria within central cores was observed. Diagnosis of myopathy with central cores was made.

Age-Related Changes in Skeletal Muscle of Cattle

Sarcopenia, the age-related loss of muscle mass and strength, is a multifactorial condition that represents a major healthcare concern for the elderly population. Although its morphologic features have been extensively studied in humans, animal models, and domestic and wild animals, only a few reports about spontaneous sarcopenia exist in other long-lived animals. In this work, muscle samples from 60 healthy Podolica-breed old cows (aged 15-23 years) were examined and compared with muscle samples from 10 young cows (3-6 years old). Frozen sections were studied through standard histologic and histoenzymatic procedures, as well as by immunohistochemistry, immunofluorescence, and Western blot analysis. The most prominent age-related myopathic features seen in the studied material included angular fiber atrophy (90% of cases), mitochondrial alterations (ragged red fibers, 70%; COX-negative fibers, 60%), presence of vacuolated fibers (75%), lymphocytic (predominantly CD8+) inflammation (40%), and type II selective fiber atrophy (40%). Immunohistochemistry revealed increased expression of major histocompatibility complex I in 36 cases (60%) and sarcoplasmic accumulations of β-amyloid precursor protein-positive material in 18 cases (30%). In aged cows, muscle atrophy was associated with accumulation of myostatin. Western blot analysis indicated increased amount of both proteins-myostatin and β-amyloid precursor protein-in muscles of aged animals compared with controls. These findings confirm the presence of age-related morphologic changes in cows similar to human sarcopenia and underline the possible role of amyloid deposition and subsequent inflammation in muscle senescence.

AKT1E¹⁷K Is Oncogenic in Mouse Lung and Cooperates with Chemical Carcinogens in Inducing Lung Cancer

The hotspot AKT1E17K mutation in the pleckstrin homology domain of AKT1 occurs in approximately 0.6-2% of human lung cancers. Recently, we have demonstrated that AKT1E17K transforms immortalized human bronchial cells. Here by use of a transgenic Cre-inducible murine strain in the wild type Rosa26 (R26) locus (R26-AKT1E17K mice) we demonstrate that AKT1E17K is a bona-fide oncogene and plays a role in the development of lung cancer in vivo. In fact, we report that mutant AKT1E17K induces bronchial and/or bronchiolar hyperplastic lesions in murine lung epithelium, which progress to frank carcinoma at very low frequency, and accelerates tumor formation induced by chemical carcinogens. In conclusion, AKT1E17K induces hyperplasia of mouse lung epithelium in vivo and cooperates with urethane to induce the fully malignant phenotype.

Age related skeletal muscle atrophy and upregulation of autophagy in dogs

Sarcopenia, the age related loss of muscle mass and strength, is a multifactorial condition that occurs in a variety of species and represents a major healthcare concern for older adults in human medicine. In veterinary medicine, skeletal muscle atrophy is often observed in dogs as they reach old age, but the process is not well understood. Autophagy is a mechanism for degradation and recycling of cellular constituents and is potentially involved in sarcopenia. The aim of the present study was to evaluate the expression of three markers of autophagy, Beclin 1, LC3 and p62, in muscle wasting of geriatric dogs, to establish whether the levels of autophagy change with increasing age. Muscle biopsies from 25 geriatric dogs were examined and compared with those from five healthy young dogs. Samples from older dogs, assessed by routine histology, histoenzymatic staining and immunohistochemistry, showed evidence of muscle atrophy, sarcoplasmic vacuolisation and mitochondrial alterations. Furthermore, in 80% of the muscle samples from the older dogs, marked intracytoplasmic staining for Beclin 1 and LC3 was observed. Significantly greater expression of LC3 II and Beclin 1, but lower expression of p62, was found by Western blotting, comparing muscle samples from old vs. young dogs. The results of the study suggest that enhanced autophagy might be one of the factors underlying muscle atrophy in dogs as they age.

Ccdc6 knock-in mice develop thyroid hyperplasia associated to an enhanced CREB1 activity

CCDC6 was originally identified upon rearrangement with RET in human thyroid papillary carcinomas generating the RET/PTC1 oncogene. We have previously reported that CCDC6 interacts with CREB1 and represses its transcriptional activity. Since the function of at least one allele of CCDC6 is lost following RET/PTC1 rearrangements, we aimed at the generation of mice, carrying a CCDC6 mutant gene. Previous studies suggested that the coiled-coil domain of CCDC6, mainly encoded by human exon 2, is required for the protein function. Therefore, we engineered a murine Ccdc6 construct, carrying a deletion of the exon 2, that was able to exert only a mild repression on CREB1 transcriptional activity, with respect to the wild type Ccdc6. Subsequently, we generated Ccdc6-ex2 knock-in mice. These mice developed thyroid hyperplasia associated with an enhanced CREB1 activity and an increased expression of the CREB-1 regulated genes. These results strongly support a CCDC6 promoting role, ascribed to its functional impairment, in the development of thyroid papillary carcinomas harboring the RET/PTC1 oncogene.

Angiostrongylus vasorum: epidemiological, clinical and histopathological insights

Background

Canine angiostrongylosis is a nematode infection in domestic dogs and wild carnivores. The present report focuses on epidemiological, clinical and histopathological findings in a case of fatal disseminated angiostrongylosis in a dog living in southern Italy and provides data on the extent of the spread of Angiostrongylus vasorum in the same area.

Case presentation

A 4-year-old female English Setter from the Campania region of southern Italy was referred with a 2-week history of cough and severe respiratory distress that did not respond to antimicrobial therapy. Based on clinical, radiological, echographical and cytological findings (including the presence of larvae), a suspect diagnosis of lungworm infection was performed. After few days the dog died due to progressive clinical aggravation. Complete postmortem examination was conducted within 24 hours from death and samples from lungs, heart, liver, kidney, spleen, stomach and small intestine were fixed in 10% buffered formalin. Grossly, several hemorrhagic foci were observed mostly in the lungs, liver, kidney. Microscopically, the lungs contained numerous, multifocal to coalescing granulomas composed of epitheliod macrophages, multinucleated giant cells and some neutrophils, frequently associated with parasite eggs and larvae. The lungs contained many firm nodules, many adult nematodes approximately 1.5 to 2 cm in length were observed in cut sections and identified as A. vasorum. A subsequent parasitological survey performed with FLOTAC on stray dogs living in the same area showed the presence of A. vasorum larvae in 17 of 1639 stray dogs examined (1.04%).

Conclusion

This survey provides new data on distribution of A. vasorum and underlines that canine angiostrongylosis should be considered as differential diagnosis in dogs.

Peritoneal morphological changes due to pneumoperitoneum: the effect of intra-abdominal pressure

INTRODUCTION

Carbon dioxide (CO2) used in laparoscopy evokes local and systemic effects. This study was designed to evaluate the histopathologic morphologic changes due to CO2 and air insufflation, at different pressure levels, on visceral and parietal peritoneum in rats.

MATERIALS AND METHODS

A total of 56 rats were object of the study, randomly divided into five groups. Pneumoperitoneum (PN) was maintained for 30 minutes, at a flow rate of 0.5 L/min and at a pressure of 10 and 6 mm Hg with CO2 (group S1-S2, n = 32) and filtered air (group A1-A2, n = 16). Only anesthesia was performed in the fifth group (group C, n = 8). Peritoneal samples were obtained 24 hours later for blinded histological evaluation. A grading system was adopted to evaluate histological peritoneal changes (0, no change; 1, mild; 2, moderate; and 3, severe) such as mesothelial aspect, inflammatory response, edema, and hemorrhage. The score reflected the severity of damage and was calculated by the sum of the degree evaluated separately. Values were compared with the analysis of variance analysis.

RESULTS

CO2 and air insufflation caused reactive mesothelial cells and peritoneal inflammation of different degrees depending on the level of intra-abdominal pressure (IAP) and type of gas. These modifications were absent in group C and were less evident in low pressure S2 group with respect to S1 and A1-A2 groups. The average values of histopathologic peritoneal score showed significant differences between S2 (11.5) versus S1 groups (16.83) with respect to A groups (A1 = 27.83; A2 = 20.5) and compared with the controls (C = 2.5).

CONCLUSIONS

Our data confirm that PN affects the peritoneal integrity. The grades of morphological peritoneal changes are related to the level of IAP. Low CO2 pressure causes minor peritoneal changes with respect to high pressure and air insufflation.

Outbreak of fatal nitrate toxicosis associated with consumption of fennels (Foeniculum vulgare) in cattle farmed in Campania region (southern Italy)

Nitrate and nitrite are toxicants that have become increasingly significant environmental chemicals. Increase in environmental distribution of nitrogenous compounds, especially in surface and ground water, has been attributed to the intensive use of nitrate as agricultural fertilizers and to increasing amounts of nitrogenous wastes produced by municipalities, industries, and feedlots. The purpose of this study is to illustrate a fatal nitrate toxicosis in cattle associated with the consumption of fennels (Foeniculum vulgare). Fifteen cows from the same farm suddenly developed weakness, muscular tremors, respiratory distress, and finally convulsions. The affected animals died within 24 to 48 h from the onset of the clinical signs. Five cows underwent a complete post-mortem examination. In all examined animals, gross lesions included presence of dark unclotted blood around the nostrils and the anal region, moderate inflammation of the gastrointestinal mucosa, and brown discoloration of the skeletal muscles and kidneys. The histological examination showed tubular degeneration and congestion of glomerular vessels in the kidney. Toxicological analysis detected nitrates at 4 672.2 ppm in the fennels used to feed the animals. The source of exposure to nitrates was identified in the fennels. The fennels were grown in a polluted area of the Campania region in southern Italy and distributed in a public market for human consumption. The waste from the sale of the fennels was fed to the cows. The accumulation of nitrates in some vegetables poses a risk not only for animal health but also for human and environmental safety.

Muscular dystrophy in a dog resembling human becker muscular dystrophy

A 3-year-old, male Labrador retriever dog was presented with clinical signs of progressive exercise intolerance, bilateral elbow extension, rigidity of the forelimbs, hindlimb flexion and kyphosis. Microscopical examination of muscle tissue showed marked variability in myofibre size, replacement of muscle with mature adipose tissue and degeneration/regeneration of muscle fibres, consistent with muscular dystrophy. Immunohistochemical examination for dystrophin showed markedly reduced labelling with monoclonal antibodies specific for the rod domain and the carboxy-terminal of dystrophin, while expression of β-sarcoglycan, γ-sarcoglycan and β-dystroglycan was normal. Immunoblotting revealed a truncated dystrophin protein of approximately 135 kDa. These findings supported a diagnosis of congenital canine muscular dystrophy resembling Becker muscular dystrophy in man.

Histiocytic sarcoma of the nasal cavity in a horse

Histiocytic diseases in veterinary medicine have been revised in the last few decades, but these are considered relatively rare in horses. This report describes a 9-year-old female horse, Dutch Warmblood, presented for investigation of severe nasal bleeding. A multinodular bilateral mass of 5 cm, reddish to white in color, that invaded and destroyed the surrounding tissues, was observed during a clinical examination of the nostril The morphological features of the tumor cells were represented by cytologically bizarre, highly phagocytic, multinucleated giant cells. These findings, together with immunohistochemical results allowed a diagnosis of histiocytic sarcoma.

Histopathological, histochemical and immunohistochemical findings of the small intestine in goats naturally infected by Trichostrongylus colubriformis

Gastrointestinal (GI) strongyle infection remains one of the main constraints to goat production worldwide. Samples of small intestine from 15 Syrian goats naturally infected with Trichostrongylus colubriformis were examined by routine histology, histochemistry and immunohistochemistry to describe the histological changes and the phenotypes of inflammatory cellular components of the mucosa. Results indicated that the immune response to infection by T. colubriformis was characterized by an increased rate of the severity of the histologic lesions, an increase rate of T cell lymphocytes recruitment to the intestinal mucosa and quantitative and qualitative changes in the histochemical composition of mucin in goblet cells.

A multicancer-like syndrome in a dog characterized by p53 and cell cycle-checkpoint kinase 2 (CHK2) mutations and sirtuin gene (SIRT1) down-regulation

INTRODUCTION

We have investigated SIRT1, p53 and cell cycle-checkpoint kinase 2 (CHK2) gene dysfunction in a dog with a multicancer syndrome-like in order to evaluate their potential role in the determinism of the disease and to establish a possible correlation between SIRT1 transcript level and p53 expression status.

MATERIAL AND METHODS

Blood sample and tumour samples from a pure breed English Setter dog with different tumours were used for this study. Nucleotide sequence analysis was performed with a DNA autosequencer in order to examine p53 and CHK2 mutations. In addition, the expression level of SIRT1 was quantified by Southern Blot analysis of Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR).

RESULTS

Cytological examination revealed five different tumours: a cutaneous sebaceous epithelioma, a cutaneous mast cell tumour, a testicular Sertoli cell tumour, an oral malignant melanoma, and a cutaneous squamous cell carcinoma. Sequencing analysis revealed the presence of a nucleotide substitution, (CGG>CAG) exon 7 of the p53 gene in DNA from peripheral blood mononuclear cells (PBMCs) as well as in the melanoma; whereas the other four cancers showed the loss of the wild-type allele. Furthermore, CHK2 mutation at codon 311 has been identified in the melanoma and sebaceous epithelioma. In addition, SIRT1 cDNA expression decreased in all tumour samples compared to cDNA SIRT1expression level in peripheral blood mononuclear cells (PBMCs) in the same dog.

CONCLUSIONS

These results suggest that the germ line mutation of the p53 gene at codon 248 might be, at least, one cause of the multicancer syndrome-like in our dog; furthermore, we show a possible correlation between SIRT1 transcript level and p53 mutations status. The regulatory role of SIRT1 in tumour suppressor pathways suggests that the net effect seen may represent both direct and indirect downstream regulation and it is likely to depend on the presence or absence of functional p53.

Syrian hamster infected with Leishmania infantum: a new experimental model for inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) are inflammatory disorders of unknown origin. On the basis of clinical, histopathological, and immunological features, they can be differentiated into three major and distinct subsets: dermatomyositis; polymyositis; and inclusion-body myositis. Although a few animal models for IIM are currently available, they lack several characteristic aspects of IIMs. The aim of our study was to examine skeletal muscle involvement in an experimental animal model of visceral leishmaniasis, a disseminated infection caused by the protozoan parasite Leishmania infantum, and to compare features of associated inflammation with those of human IIM. Syrian hamsters infected intraperitoneally with amastigotes of L. infantum were killed at 3 or 4 months post-infection, and the skeletal muscles were studied. Focal inflammation was predominantly observed in the endomysium and, to a lesser extent, in perivascular areas. Degenerating muscle fibers were also found, as well as myonecrosis. Immunofluorescence with confocal laser scanning microscopy was used to characterize the phenotype of inflammatory infiltrates and the distribution of MHC class I and II in muscle biopsies. The infiltrating inflammatory cells consisted mainly of T cells, and CD8(+) T cells were found in non-necrotic muscle fibers that expressed MHC class I on the sarcolemma. In addition to T cells, several macrophages were present. The model we are proposing closely resembles polymyositis and may be useful in studying certain aspects of this disease such as the role of T cells in muscle inflammation and myocytotoxicity, while also providing novel therapeutic targets.

Isolated lepromatous conjunctivo-corneal granuloma in a cat from Italy

OBJECTIVE

To describe a case of a conjunctivo-corneal mass in a cat associated with acid-fast bacilli.

METHODS

A 2-year-old female black European Short-Hair cat, living outdoors in a suburban environment in Italy, was referred for evaluation of a nodular, vascularized mass of 2 weeks duration. The mass involved the dorsal bulbar conjunctiva at the temporal canthus of OS and invaded the sclera and cornea. Routine ophthalmic and systemic examination, serologic testing, cytology and histology of the mass were performed. Mycobacterium specific polymerase chain reaction (PCR) of variable regions 1, 2 and 3 of the 16S ribosomal RNA (rRNA) gene was also performed.

RESULTS

Neutrophils, lymphocytes, macrophages and giant cells with intracytoplasmic acid-fast bacilli were seen on cytological examination. The histological examination confirmed the presence of a granulomatous lesion with acid-fast bacilli within macrophages. Bacteriological culture of the material from the lesion was negative for Mycobacterium spp. Mycobacterium 16S rRNA gene specific PCR was positive. A diagnosis of feline leprosy was made. The owners refused any treatment, and 1 year later the lesion was still present.

CONCLUSIONS

Veterinary ophthalmologists should be aware of conjunctivo-corneal leproma as an unusual symptom of leprosy.

Morphological characterisation of malignant histiocytosis in a cat

Malignant histiocytosis (MH) is a progressive systemic neoplastic proliferation of morphologically atypical histiocytes, well characterised in humans and dogs but only recently identified in the cat. In all species, liver, lung, lymph nodes, spleen and bone marrow are infiltrated by atypical histiocytes, and the disease is rapidly fatal. The purpose of this study was to describe the clinical, histological, immunohistochemical and ultrastructural findings of MH in a cat, together with the diagnostic work-up and a list of differential diagnoses. Clinical evaluation included a complete blood-cell count, serum biochemistry, urinalysis, serology and ultrasound examination. The cat had clinical signs of depression, thinness, dehydration, pale mucous membranes and tachycardia. Abdominal ultrasonography revealed generalised splenomegaly and hepatomegaly. Necroscopy showed whitish nodules, randomly scattered throughout the parenchyma in the spleen and liver. The periportal lymph nodes were greatly enlarged and the cut surface was uniformly greyish-white and translucent. Histological examination revealed pleomorphic proliferation of large round tumour cells, with numerous phagocytic vacuoles containing erytrocytes, leukocytes and haemosiderin. By immunohistochemistry, positivity for lysozyme and alpha1-antitrypsin and a scattered positivity for Mac 387 were observed. Ultrastructural features of tumour cells included cytoplasmic lipid droplets, lysosomes and phagolysosomes. MH in the cat needs to be differentiated from diffuse granulomatous disease, non-Hodgkin's lymphoma and Hodgkin's-like disease. The morphological features of the tumour cells, combined with immunohistochemical and ultrastructural observation, are consistent with a diagnosis of MH in the cat.

Expression of peroxisome proliferator-activated receptor gamma (PPAR-gamma) in canine nasal carcinomas

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a ligand-activated transcriptional factor belonging to the steroid receptor superfamily. PPAR-gamma is expressed in multiple normal and neoplastic tissues, such as the breast, colon, lung, ovary and placenta. In addition to adipogenic and anti-inflammatory effects, PPAR-gamma activation has been shown to be anti-proliferative by its differentiation-promoting effect, suggesting that activation of PPAR-gamma may be useful in slowing or arresting the proliferation of de-differentiated tumour cells. In this study, we investigated the expression of PPAR-gamma in normal and neoplastic canine nasal epithelium. Twenty-five samples composed of five normal nasal epithelia and 20 canine nasal carcinomas, were immunohistochemically stained for PPAR-gamma. The specificity of the antibody was verified by Western Blot analysis. Confocal laser scanning microscopical investigation was also performed. In normal epithelium, the staining pattern was cytoplasmic and polarized at the cellular free edge. In carcinomas, the neoplastic cells showed mainly strong cytoplasmatic PPAR-gamma expression; moreover, perinuclear immunoreactivity was also detected and few neoplastic cells exhibited a nuclear positivity. Our results demonstrate different patterns of PPAR-gamma expression in normal canine nasal epithelium when compared with canine nasal carcinoma. The importance of this transcription factor in the pathophysiology of several different tumours has stimulated much research in this field and has opened new opportunities for the treatment of the tumours.

Local and systemic impact of pneumoperitoneum on prepuberal rats

Pneumoperitoneum (PN) and the gas used to insufflate the abdominal cavity during laparoscopy seem to be responsible for local and systemic modifications. The aim of this study was to verify the effects of intra-abdominal carbon dioxide (CO(2)) and air insufflation on the peritoneum, as well as the cortico-surrenal response in prepuberal rats. Sixty prepuberal rats were divided into three groups: in the first (S, n = 36), PN was induced with CO(2), whereas in the second (A, n = 14), it was induced with filtered room air; in both conditions, insufflation lasted 30 min at a pressure of 10-12 mmHg. The third group (C, n = 10), underwent general anesthesia only. Two hours after inducing anaesthesia, 12 rats in group S, 6 in group A and 6 in group C were killed and the remaining, after 24 h; specimens of the visceral and the parietal peritoneum were obtained for histological examination, blood sample was taken for cortisol and DHEA-S assays at the different study periods. At the histological examination performed 2 h later, the groups S and A presented inflammatory cell infiltrate in the parietal and visceral peritoneum; this finding was even more marked in group A, which presented also congestion, hemorrhage and disruption of the cell line. Twenty-four hours after the experiment, the peritoneum of the two insufflated groups presented chronic infiltrate and reactive mesothelial cells with congestion, which was more evident in group A, but totally absent in group C. Cortisol levels were significantly higher in groups S and A (2.15:1 ratio) killed 2 h later compared to those killed 24 h later and to the control group. DHEA-S levels were not significantly different between the groups. Our results demonstrate that the chemical, physical and molecular impact of CO(2) on the peritoneum causes inflammation and tissue damage, this was even more evident 24 h after our experiment and in the air insufflated group. PN induced a significant variation in blood cortisol levels at 2 h. The CO(2) insufflation should be limited in patients with pre-existing peritoneal damage.

Expression of major histocompatibility complex class I and class II antigens in canine masticatory muscle myositis

Studies in human immune-mediated inflammatory myopathies have documented expression of major histocompatibility complex class I (MHC class I) and class II (MHC class II) antigens on muscle fiber membranes in the presence or absence of cellular infiltration. Here we evaluate the presence and distribution of these antigens in canine masticatory muscle myositis, an immune-mediated inflammatory myopathy. Twelve samples of temporalis and masseter muscles from dogs with a clinical diagnosis of canine masticatory muscle myositis were examined by immunohistochemistry and double-immunofluorescence confocal microscopy. MHC class I and class II antigens were expressed in muscle fibers independent of inflammatory cell infiltration. Furthermore MHC class I and class II antigens were expressed on the sarcolemma and co-localized with dystrophin. Our results suggest that MHC class I and class II expression in canine masticatory muscle myositis may play a role in the initiation and maintenance of the pathological condition, rather than just a consequence of a preceding local inflammation.

Evaluation of static telepathology in veterinary diagnostic cytology

BACKGROUND

Telepathology is the process of diagnostic pathology performed on digital images viewed on a display screen rather than by conventional light microscopy with glass slides. At present, electronic mail (e-mail) attachment is the most common communication medium for telepathology, because it is relatively simple and incurs minimal cost.

OBJECTIVE

Our objective was to test whether telediagnosis through Internet e-mail could be applied to veterinary diagnostic cytology.

METHODS

Using 20 cytology cases, on which a consensus diagnosis was reached by 3 experienced pathologists, a total of 130 images were digitized and sent as e-mail attachments from the Unit of Anatomic Pathology of the Faculty of Veterinary Medicine of Naples to the Unit of Pathology of the Faculty of Veterinary Medicine of Messina, Italy. The images were reviewed at the Unit of Pathology of Messina, where the consulting pathologist formulated his diagnoses by visualizing the images on the monitor of a computer. The telediagnoses were compared with the consensus diagnoses and with the consulting pathologist's interpretation using conventional light microscopy at a later date.

RESULTS

The median time to capture images was approximately 30 minutes for each case. The median time to make a telecytodiagnosis was a few seconds for each case. Overall, there was good agreement (85%) between the consensus diagnosis and the consultant's telediagnosis. In 100% of the cases there was agreement between the consulting pathologist's telediagnosis and conventional glass slide diagnosis.

CONCLUSION

Telepathology by e-mail provides acceptable efficacy and a faster turnaround time than post and can be applied to veterinary diagnostic cytology.

Expression of cyclooxygenase-1 and -2 in canine nasal carcinomas

Cyclooxygenase-1 (COX-1) and cyclooxygenase -2 (COX-2) are known to play a role in the carcinogenesis of many human and animal primary epithelial tumours. However, expression of COX-1 and -2 has not been investigated in canine nasal epithelial carcinoma, a rare form of neoplasia. COX-1 immunolabelling was demonstrated in normal canine nasal mucosa and in a minority of neoplastic specimens. Cytoplasmic COX-2, however, was strongly expressed in the majority of canine nasal carcinomas. In addition, COX-2 expression was demonstrated in dysplastic epithelium and in a proportion of stromal cells. Co-expression of both enzyme isoforms was revealed by confocal laser scanning microscopy. The results indicate that COX-2 is overexpressed in a proportion of naturally occurring canine nasal carcinomas, suggesting its possible role in canine nasal tumorigenesis.