Presumptive metastatic leiomyosarcoma in a feedlot steer.

A 14-month-old feedlot steer was depressed and died while being examined. The gross post-mortem examination of the steer conducted at the feedlot identified numerous masses within the abdomen and thorax, including a large mass in the liver that eroded into the vena cava. Many masses in the lungs appeared to be the result of hematogenous distribution. Histologic examination of the masses confirmed the presence of neoplasia. Although the histologic appearance of the neoplasms was not typical of well-differentiated leiomyosarcoma, immunohistochemical staining supported that diagnosis. Leiomyosarcomas are rare among North American cattle. In this case, the primary neoplasm appears to have originated in the wall of the vena cava within the liver. Key clinical message: This report adds to the limited information on leiomyosarcomas in cattle, while highlighting both the challenges faced by veterinarians conducting post-mortem examinations on large animals in below freezing temperatures, as well as the current methods available to arrive at a diagnosis of a rare disease.

Léiomyosarcome métastatique présumé chez un bouvillon de parc d'engraissement. Un bouvillon de parc d'engraissement âgé de 14 mois était abattu et est mort pendant son examen. L'examen macroscopique du bouvillon réalisée au parc d'engraissement a identifié de nombreuses masses dans l'abdomen et le thorax, y compris une grosse masse dans le foie qui s'est étendue dans la veine cave. De nombreuses masses dans les poumons semblaient être le résultat d'une distribution hématogène. L'examen histologique des masses a confirmé la présence d'un néoplasme. Bien que l'aspect histologique du néoplasme ne soit pas typique d'un léiomyosarcome bien différencié, la coloration immunohistochimique a corroboré ce diagnostic. Les léiomyosarcomes sont rares chez les bovins nord-américains. Dans ce cas, le néoplasme primaire semble provenir de la paroi de la veine cave dans le foie.Message clinique clé :Ce rapport s'ajoute aux informations limitées sur les léiomyosarcomes chez les bovins, tout en soulignant à la fois les défis auxquels sont confrontés les vétérinaires effectuant des examens post-mortem sur de grands animaux à des températures inférieures au point de congélation, ainsi que les méthodes actuelles disponibles pour arriver à un diagnostic d'une maladie rare.(Traduit par Dr Serge Messier).

Metallothionein Expression in Horses With Chronic Liver Disease and Its Correlation With Ki-67 Immunoreactivity.

Chronic liver disease is an important cause of illness in horses, and treatment is mainly supportive. Research into new treatment modalities for humans has shown promising data regarding metallothionein (MT), which has been shown to possess regenerative, antifibrotic, and anti-inflammatory properties. This study aimed to examine the relationship between hepatic MT expression and the histopathologic markers of hepatic inflammation, fibrosis and bile duct proliferation, as well as cellular regeneration in 77 selected cases of chronic liver disease in horses. We hypothesized that higher MT expression would be associated with increased heptocellular proliferation and decreased fibrosis, inflammation, and bile duct proliferation. Hepatocellular MT expression was evaluated with immunohistochemistry. Additionally, cellular regeneration was evaluated with immunohistochemistry for Ki-67, a protein expressed during all active stages of the cell cycle. The severity of inflammation and fibrosis was scored, and bile duct proliferation was assessed by counting bile duct profiles. MT expression was observed in 73 of 77 (94.8%) cases of chronically diseased livers. Ki-67 expression was seen in resident Kupffer cells ( n = 42, 54.6%), lymphocytes ( n = 39, 50.7%), bile duct epithelium ( n = 10, 13.0%), and hepatocytes ( n = 8, 10.4%). MT expression was significantly associated with Ki-67 staining in bile duct epithelium and Kupffer cells. Additionally, median MT expression was higher in cases containing lymphocytic infiltrates as compared with cases with no lymphocytic infiltrate ( P < .05). These findings are the first known report of MT expression within chronic equine hepatic disease.

Chronic active interstitial pancreatitis as a cause of transverse colonic obstruction and colic in a horse.

A mature Quarter horse was euthanized following colic of 3 days duration. Postmortem, the large intestine, except the descending colon, was diffusely distended and associated with adhesion of the transverse colon to the pancreas, which had changes consistent with chronic active interstitial pancreatitis. Other lesions included hepatic fibrosis, erosive gastritis, and bilateral adrenal cortical hyperplasia.

Pancréatite interstitielle chronique active comme cause d'une obstruction du côlon transversal et de coliques chez un cheval. Un cheval Quarter horse adulte a été euthanasié après des coliques d'une durée de 3 jours. À l'autopsie, il a été observé que le gros intestin, sauf le côlon descendant, présentait une distension diffuse et était associé à l'adhésion du côlon transversal au pancréas qui indiquait des changements conformes à une pancréatite interstitielle chronique active. Les autres lésions incluaient une fibrose hépatique, une gastrite érosive et une hyperplasie corticale bilatérale des surrénales.(Traduit par Isabelle Vallières).

The lesions of toe tip necrosis in southern Alberta feedlot cattle provide insight into the pathogenesis of the disease.

Gross and histologic postmortem studies were performed on the hind feet of feedlot cattle that had, or were free from, lesions of toe tip necrosis. The hind feet of feedlot cattle were collected by 3 veterinary feedlot practices in southern Alberta, Canada. Three studies of these feet were conducted: i) prediction of disease based on the presence or absence of apical white line separation, ii) gross assessment of the distribution and severity of lesions within affected claws, and iii) microscopic evaluation of the distal phalanx and surrounding soft tissues of affected claws. Prediction of toe tip necrosis based on the presence of apical white line separation was statistically significant (P < 0.0001). This, combined with a pattern of lesions indicative of an ascending infection of the distal phalanx and the absence of other lesions, suggests that the pathogenesis involves bacterial infection originating from the most distal aspect of the toe, at the apical white line.

Les lésions de la nécrose du bout des orteils chez le bétail des parcs d'engraissement du sud de l'Alberta fournissent des renseignements sur la pathogénèse de la maladie. Des études post-mortem macroscopiques et histologiques ont été réalisées sur les pieds arrière du bétail d'engraissement qui avait ou n'avait pas des lésions de nécrose du bout des orteils. Les pieds arrière du bétail d'engraissement ont été recueillis par trois pratiques vétérinaires de parcs d'engraissement du sud de l'Alberta, au Canada. Trois études de ces pieds ont été réalisées : i) prédiction de la maladie en fonction de la présence ou de l'absence d'une séparation de la ligne blanche apicale, ii) une évaluation macroscopique de la répartition et de la gravité des lésions dans les onglons affectés et iii) une évaluation microscopique des phalanges distales et des tissus mous entourant les onglons affectés. La prédiction de la nécrose du bout des orteils basée sur la présence d'une séparation de la ligne blanche apicale était significative du point de vue statistique (P < 0,0001). Ce fait, combiné à une tendance de lésions indiquant une infection ascendante des phalanges distales et l'absence d'autres lésions, suggère que la pathogénèse comporte une infection bactérienne provenant de l'aspect le plus distal de l'orteil, à la ligne blanche apicale.(Traduit par Isabelle Vallières).

Optic neuropathy in a herd of beef cattle in Alberta associated with consumption of moldy corn.

A group of beef cattle in eastern Alberta was investigated due to sudden onset of blindness after grazing on standing corn in mid-winter. Fumonisin-producing Fusarium spp. were isolated from the corn. Blindness was due to an optic nerve degeneration suspected to be secondary to fumonisin mycotoxin.

Neuropathie optique dans un cheptel de bovins de boucherie en Alberta associée à la consommation de maïs moisi. Un groupe de bovins de boucherie de l'est de l'Alberta a fait l'objet d'une enquête en raison de l'apparition soudaine de cécité après avoir brouté du maïs sur pied vers le milieu de l'hiver. Fusarium spp., qui produit la fumonisine, a été isolé dans le maïs. La cécité a été attribuable à la dégénération du nerf optique ayant pour cause suspectée la mycotoxine fumonisine.(Traduit par Isabelle Vallières).

A retrospective study of spinal cord lesions in goats submitted to 3 veterinary diagnostic laboratories.

A retrospective study of spinal cord lesions in goats was conducted to identify the range of lesions and diseases recognized and to make recommendations regarding the best tissues to examine and tests to conduct in order to maximize the likelihood of arriving at a definitive etiologic diagnosis in goats with clinical signs referable to the spinal cord. Twenty-seven goats with a spinal cord lesion were identified. The most common lesion recognized, in 13 of 27 goats, was degenerative myelopathy. Eight goats with degenerative myelopathy were diagnosed with copper deficiency. Non-suppurative inflammation due to caprine arthritis encephalitis virus, necrosis due to parasite larvae migration, and neoplasia were each diagnosed 3 times. Based on these findings, it is recommended that, in addition to careful handling and histologic examination of the spinal cord, samples of other tissues, including the brain, liver, and serum, be collected for ancillary testing if warranted.

Evaluation of a minimally invasive arthrodesis technique for the carpometacarpal joint in horses.

OBJECTIVE: To evaluate a minimally invasive technique for arthrodesis of the carpometacarpal (CMC) joint in horses. STUDY DESIGN: Experimental study. ANIMALS: Healthy horses (n=6). METHODS: A 5.5 mm, 3-drill tract arthrodesis technique was evaluated in 1 randomly selected CMC joint in each of 6 normal horses. Peak vertical ground reaction force (GRF) values were recorded before surgery and at 6, 8, and 12 months thereafter. Radiographic and clinical lameness scores were assigned at regular intervals until 12 months after surgery when the horses were euthanatized. Gross and histologic examinations were performed on the treated CMC joints. RESULTS: After surgery, all horses were lame. Clinical resolution of lameness occurred in 2 by 12 months. Mean peak vertical GRF values significantly differed between treated and nontreated limbs at all recorded time points after surgery. Radiographic scores significantly differed from day 0 at all times after surgery, but did not change significantly after 4 months. Intraarticular bony ankylosis only occurred in 2 horses, based on gross, histologic, and microradiographic examination of sagittal sections of the operated CMC joints. CONCLUSION: The 5.5 mm, 3-drill tract arthrodesis technique was considered successful in only 2 of 6 normal CMC joints treated. Greater articular damage may be necessary to achieve arthrodesis in normal horses. Better results may be achieved by technique modification or in horses affected by CMC osteoarthritis.

Evaluation of ethyl alcohol for use in a minimally invasive technique for equine proximal interphalangeal joint arthrodesis.

OBJECTIVE: To determine whether intra-articular 70% ethyl alcohol alone (IAEA) or in combination with 2 percutaneously placed transarticular lag screws (EA-TLS) would result in arthrodesis of the equine proximal interphalangeal (PIP) joint. STUDY DESIGN: Experimental. ANIMALS: Healthy horses (n=6), aged 1.5-3 years, free of lameness, diagonally paired front and hind PIP joints. METHODS: Six milliliters 70% ethyl alcohol was injected into randomly selected diagonally paired front and hind PIP joints. Thirty days later, 2 parallel 5.5 mm cortical screws were inserted in lag fashion across the hind PIP joints and the limbs were cast. Horses were confined for 60 days after surgery before free exercise was permitted. Serial lameness examinations were performed at 1, 6, and 10 months. Radiographs of the PIP joints were obtained before injection with alcohol (front, hind PIP joints), at 6 and 10 months (front PIP joints) and 1, 3, 6, and 10 months (hind PIP joints). At 10 months, horses were euthanatized and gross and histopathologic examination of the treated joints was performed. RESULTS: Horses had variable cartilage thinning (more severe in hind PIP joints) and dorsal bone proliferation. One front and 1 hind PIP joint were fused 10 months after alcohol injection. CONCLUSIONS: Ethyl alcohol injected alone or in combination with percutaneously placed transarticular lag screws failed to reliably produce fusion of the PIP joint.

Evaluation of metallothionein and Ki-67 expression in chronic cholangiohepatitis in cats.

Chronic cholangiohepatitis (CCH) is a common pathological condition in cats with a guarded prognosis and unknown etiology. Recently, in human medicine, there has been increased interest in enhancing liver defense mechanisms as an effective treatment strategy to control liver diseases that have a poor prognosis. Metallothionein (MT) is a ubiquitous protein, which has been widely researched for its role in liver defense through heavy metal detoxification, neutralization of reactive oxygen species, and liver regeneration. In this study, immunohistochemistry was used to evaluate the role of MT in CCH and hepatocellular regeneration in 34 cats histologically diagnosed with this condition by assessing the correlation between hepatocellular MT and Ki-67 (marker for cellular proliferation) expression with histological parameters of CCH, such as inflammation, fibrosis, and bile duct proliferation. Statistical analysis was performed using the Spearman-rank correlation test. A significant positive correlation was observed between inflammation and the number of MT-positive hepatocytes (r = 0.36, P = 0.03) and MT labelling intensity (r = 0.37, P = 0.03). In 16 of 34 cases (47%) MT labelling intensity was noted to be pronounced towards the centrilobular zone and very weak or absent towards the portal zone. The results suggest that MT is induced in the liver during chronic inflammatory conditions, which could be speculated as a host defensive mechanism to protect the liver from inflammation-mediated liver injury. Therapeutic interventions utilizing MT, therefore, may have a positive effect on cats with chronic cholangiohepatitis.

La cholangiohépatite chronique (CCH) est une affection pathologique courante chez les chats avec un pronostic réservé et une étiologie inconnue. Récemment, en médecine humaine, il y a eu un intérêt accru pour l'amélioration des mécanismes de défense hépatique en tant que stratégie de traitement efficace pour contrôler les maladies du foie qui ont un mauvais pronostic. La métallothionéine (MT) est une protéine omniprésente, qui a été largement étudiée pour son rôle dans la défense du foie par la détoxification des métaux lourds, la neutralisation des espèces réactives de l'oxygène et la régénération du foie. Dans cette étude, l'immunohistochimie a été utilisée pour évaluer le rôle de la MT dans la CCH et la régénération hépatocellulaire chez 34 chats diagnostiqués histologiquement avec cette condition en évaluant la corrélation entre l'expression hépatocellulaire de la MT et du Ki-67 (marqueur de la prolifération cellulaire) avec les paramètres histologiques de la CCH, comme l'inflammation, la fibrose et la prolifération des voies biliaires. L'analyse statistique a été réalisée à l'aide du test de corrélation de rang de Spearman. Une corrélation positive significative a été observée entre l'inflammation et le nombre d'hépatocytes MT-positifs (r = 0,36, P = 0,03) et l'intensité de marquage MT (r = 0,37, P = 0,03). Dans 16 des 34 cas (47 %), l'intensité du marquage MT était prononcée vers la zone centrolobulaire et très faible ou absente vers la zone porte. Les résultats suggèrent que la MT est induite dans le foie pendant les états inflammatoires chroniques, ce qui pourrait être supposé comme un mécanisme de défense de l'hôte pour protéger le foie contre les lésions hépatiques induites par l'inflammation. Les interventions thérapeutiques utilisant la MT peuvent donc avoir un effet positif sur les chats atteints de cholangiohépatite chronique.(Traduit par Docteur Serge Messier).

Induration of the cricoid cartilage complicates prosthetic laryngoplasty in a horse.

OBJECTIVE: To report intraoperative complications during needle penetration and suture placement through the cricoid cartilage during a prosthetic laryngoplasty procedure. STUDY DESIGN: Case report. METHODS: An 11-year-old American Paint gelding with grade IV left laryngeal hemiplegia underwent a terminal prosthetic laryngoplasty for teaching purposes. Passage of the needle through the cricoid cartilage was difficult and resulted in needle breakage before eventual success using a new needle. The larynx was examined postmortem. RESULTS: Palpation of the larynx revealed hardening of the cricoid cartilage. Radiographic examination indicated the presence of diffuse radiopaque speckling. Histologic examination did not find accumulations of calcium salts, rather it revealed a loss of proteoglycans within the cricoid cartilage. CONCLUSIONS: Laryngeal mineralization occurs in the horse and human with advancing age. The loss of proteoglycan and subsequent stiffening of the cricoid cartilage likely resulted in the intraoperative complications noted in this report. CLINICAL RELEVANCE: Radiographic examination of the larynx before performing a prosthetic laryngoplasty may reveal the presence of areas of increased radiodensity. The interpretation of this is to be made with caution as it may represent mineralization, or hardening due to the changes in proteoglycan concentration, monomer size or charge.

Penetrating metallic foreign bodies as a cause of peritonitis in 3 horses.

Three cases of penetrating metallic foreign bodies causing peritonitis in horses are reported. These cases were presented with varying clinical complaints and duration of clinical signs. Entry of foreign bodies into the abdominal cavity through the skin and body wall is reported for the first time.

Epidemiology of equine sarcoids in horses in western Canada.

Sarcoids are the most common tumor of the equine skin but only 1 study describing the epidemiology of sarcoids in Canadian horses has been published. The records of 5 veterinary diagnostic laboratories in western Canada were searched to identify submissions of sarcoids from horses. The submission records and diagnostic reports of 802 separate submissions of equine sarcoids were reviewed for age, breed, and gender of the horse and the number, location, and clinical type of sarcoid. From these records, the 307 submissions to laboratories in Saskatchewan were compared to a reference group to test for breed and gender predisposition. Based on clinical history and lesion descriptions, 5 clinical types of sarcoids were identified. Horses of various ages and 23 equine breeds were affected; donkeys were over-represented. Polymerase chain reaction (PCR) for the bovine papillomavirus (BPV) DNA was performed on formalin-fixed paraffin-embedded tissues from a stratified subset of 96 of the different clinical types; BPV2 was present in 60 of 74 (81%) for which a PCR product was obtained. Unlike other areas in the world, in western Canada, equine sarcoids are most commonly associated with BPV type 2.

Canine eosinophilic pulmonary granulomatosis: case report and literature review.

We describe and illustrate herein a case of eosinophilic pulmonary granulomatosis (EPG) in a 16-mo-old, castrated male, Great Pyrenees crossbred dog. EPG appears to differ from eosinophilic pneumonias and eosinophilic bronchopneumopathy in dogs by the presence of nodules and masses in the lungs composed of eosinophils, macrophages, and various combinations of lymphocytes, plasma cells, neutrophils, and mast cells within fibrous tissue. Specific information from this dog was added to the information from the limited number of other dogs diagnosed with EPG reported in the veterinary literature, and the information analyzed. EPG appears to have no breed or sex predilection and tends to be a disease of younger dogs, often ≤ 3 y of age. Antemortem imaging of nodules and masses in the lungs, combined with cytologic evidence of eosinophils in the lesions, is highly suggestive of EPG, and the diagnosis can be confirmed postmortem. Concurrent eosinophilia and basophilia can be features of EPG, but their diagnostic value requires further investigation, as does the possible causal association with Dirofilaria immitis infection.

Comparison of three drilling techniques for carpometacarpal joint arthrodesis in horses.

OBJECTIVE: To evaluate 3 drilling techniques for arthrodesis of the equine carpometacarpal (CMC) joint. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric equine forelimbs (n=15). METHODS: Limbs were divided into 3 groups (5 limbs each) to evaluate 3 drilling techniques: (1) use of a 4.5 mm drill bit inserted into the joint through 4 entry points and moved in a fanning motion; (2) a 5.5 mm drill bit inserted through 2 entry points to create 3 nonfanned drill tracts (3 drill technique); and (3) a 4.5 mm drill bit used in a 3 drill technique. The CMC joint was disarticulated after drilling, and cartilage and subchondral bone damage evaluated visually and by gross and microradiographic examination using planimetry. RESULTS: Technique 1 produced significantly more damage of the proximal surface, but significantly less to the subchondral bone of the distal surface. Technique 1 produced the most damage to both the articular cartilage and subchondral bone of the total CMC joint than either of the 3 drill tract techniques; however, the difference between techniques 1 and 2 was not significant. Damage from technique 3 was significantly less than that with techniques 1 or 2. CONCLUSIONS: Techniques 1 and 2 produced the most cartilage and subchondral bone damage with technique 2 changes more equally distributed between proximal and distal joint surfaces. CLINICAL RELEVANCE: Technique 1 (fanning) and 2 (5.5 mm 3 drill tracts) may be preferable to achieve arthrodesis of the CMC joint. Morbidity and efficacy of these arthrodesis techniques need to be evaluated in vivo.

Histologic assessment of age-related changes in the temporomandibular joints of horses.

OBJECTIVE: To describe histologic changes in the temporomandibular joints (TMJs) of horses of various ages. SAMPLE: 22 TMJs from cadavers of 11 horses. PROCEDURES: Horses were categorized into 3 age groups (group 1, 2 to 10 years old [n = 3]; group 2, 11 to 20 years old [3]; and group 3, > 20 years old [5]). Each TMJ was sectioned into 5-mm slices, preserved in formalin, decalcified in formic acid, and routinely processed for histologic analysis. Joints were systematically assessed by use of previously described methods. Multilevel mixed-effects models were used to examine the data. RESULTS: The number of changes was significantly fewer and degree of changes was significantly less within the TMJs of group 1 horses, compared with those of group 3 horses. Comparison among groups revealed that the combination of temporal and mandibular scores for group 1 was significantly lower than for groups 2 or 3. Disk score did not differ significantly between groups 1 and 2, but disk scores of groups 1 and 2 were significantly lower than the disk score of group 3. CONCLUSIONS AND CLINICAL RELEVANCE: The assessed lesions were associated with osteoarthritis, and they accumulated in the TMJs as horses aged. In the absence of signs of pain manifested as changes in mastication, behavior, or performance, it would be difficult to determine the point at which accrued pathological changes represented the onset of clinically important osteoarthritis of the TMJs.

Novel technique for prevention of rotation of the distal phalanx relative to the hoof wall in horses with acute laminitis.

OBJECTIVE: To determine the holding capacity of a 5.5-mm-diameter cortical bone screw when placed in the third phalanx (P3) of horses and assess whether screw placement through the dorsal hoof wall into P3 would be tolerated by clinically normal horses and would alleviate signs of pain and prevent P3 rotation in horses with oligofructose-induced laminitis. ANIMALS: 40 limbs from 10 equine cadavers and 19 clinically normal adult horses. PROCEDURES: In part 1 of a 3-part study, a 5.5-mm-diameter cortical bone screw was inserted by use of a lag-screw technique through the dorsal hoof wall midline into P3 of 40 cadaveric limbs and tested to failure to determine screw pullout force. In part 2, 6 horses had 5.5-mm-diameter cortical bone screws placed in both forefeet as described for part 1. Screws were removed 4 days after placement. Horses were monitored for lameness before and for 2 weeks after screw removal. In part 3, 13 horses were randomly assigned to serve as controls (n = 3) or undergo screw placement without (group 2; 6) or with (group 3; 4) a washer. Following the acquisition of baseline data, horses were sedated and administered oligofructose (10 g/kg) via a stomach tube. Twenty-four hours later, screws were placed as previously described in both forefeet of horses in groups 2 and 3. Horses were assessed every 4 hours, and radiographic images of the feet were obtained at 96 and 120 hours after oligofructose administration. Horses were euthanized, and the feet were harvested for histologic examination. RESULTS: The mean ± SD screw pullout force was 3,908.7 ± 1,473.4 N, and it was positively affected by the depth of screw insertion into P3. Horses of part 2 tolerated screw placement and removal well and did not become lame. All horses of part 3 developed signs of acute lameness, and the distance between P3 and the dorsal hoof wall increased slightly over time. The change in the ratio of the dorsal hoof wall width at the extensor process of P3 to that at the tip of P3 over time was the only variable significantly associated with treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Placement of a 5.5-mm-diameter cortical bone screw through the dorsal hoof wall into P3 had sufficient holding power to counteract the pull of the deep digital flexor tendon in approximately 500-kg horses, and placement of such a screw was well tolerated by clinically normal horses but did not alleviate signs of pain in horses with oligofructose-induced laminitis. Further research is necessary before this technique can be recommended for horses with naturally occurring acute laminitis.

Canine brucellosis in a Saskatchewan kennel.

Canine brucellosis is rare in Canada. This report describes an outbreak of Brucella canis infection within a kennel, emphasizing diagnostic and pathologic findings. Gender differences are described. The progestational, nongravid uterus, female spleen, and prostate gland are consistent sites of bacterial isolation.

Profiles of pro-opiomelanocortin and encoded peptides, and their processing enzymes in equine pituitary pars intermedia dysfunction.

Equine pituitary pars intermedia dysfunction (PPID) is characterized by hyperplasia of the pars intermedia (PI) melanotrophs of the pituitary gland (PG), and increased production of proopiomelanocortin (POMC). POMC is cleaved by prohormone convertase 1 (PC1) to produce adrenocorticotropic hormone (ACTH), and further processing of ACTH by PC2 to produce alpha-melanocyte stimulating hormone (α-MSH) and corticotropin-like intermediate peptide (CLIP). High plasma ACTH concentrations in horses with PPID might be related to reduced conversion of ACTH to α-MSH by PCs. The hypothesis of this study was that PC1 and PC2 expression in the pituitary gland are altered in PPID, resulting in an abnormal relative abundance of POMC derived proteins. The objectives of this study were to identify the partial sequences of equine POMC, PC1, and PC2 mRNAs; and to determine whether the expression of POMC, PC1, and PC2 mRNAs in whole pituitary extracts, and POMC-protein in the cavernous sinus blood of horses are altered in PPID. We confirmed (RT-PCR and sequencing) that the partial sequences obtained match the corresponding regions of predicted equine POMC, PC1 and PC2 sequences. The expression (quantification by RT-qPCR) of POMC, PC1 and PC2 mRNAs were found upregulated in the pituitary of horses with PPID. Plasma (measured using RIA/ELISA) ACTH and α-MSH were elevated in PPID horses. These results indicate distinct differences in gene and protein expression of POMC and its intermediates, and processing enzymes in PPID. It provides evidence to support the notion that local, pituitary-specific inadequacies in prohormone processing likely contribute to equine PPID.

Agreement among surgical pathologists evaluating routine histologic sections of digits amputated from cats and dogs.

Agreement among pathologists interpreting histologic specimens is an area of interest within human pathology, but little work in this area has been reported in the veterinary literature. Agreement among pathologists evaluating routine histologic sections of amputated digits from cats and dogs submitted to multiple diagnostic centers was examined. Histologic sections from surgical specimens were reviewed in a blinded fashion by two pathologists, and a comparison to the original diagnosis, as stated in the diagnostic report, was recorded. A total of 513 cases were reviewed, and complete agreement was reached in 409 (79.7%). Of the 104 instances of disagreement, 77 (74.0%) were considered to be of clinical significance. The diagnosis of keratoacanthoma was disagreed with in 19 of 21 diagnoses (90.4%). No other individual diagnosis was similarly disputed. The overall level of disagreement is large and is similar to that reported in human pathology and suggests that further study of this issue would be useful in veterinary pathology.

Insulinoma in a dog with pre-existing insulin-dependent diabetes mellitus.

A 10-year-old golden retriever with a 3-year history of insulin-dependent diabetes mellitus was presented with recurring episodes of hypoglycemia and seizures. A presumptive diagnosis of an insulinoma was made based on hypoglycemia with concurrent endogenous hyperinsulinemia and unremarkable radiographic and ultrasonographic images of the chest and abdomen. A beta cell carcinoma of the pancreas with metastasis to the liver and a mesenteric lymph node was confirmed by surgery and histopathology.