Canine astrocytic tumors: a comparative review

Tumors of astrocytic lineage are among the most common primary brain neoplasms in people and dogs. Current understanding of the pathogenesis of astrocytic tumors is limited in dogs compared with humans. In dogs, critical biological data concerning the natural history of disease progression, tumor imaging features, and response to therapeutic intervention are lacking. This review outlines the clinical, genetic, immunologic, and histopathologic characteristics of astrocytic tumors in dogs with special focus on comparative neuro-oncology. Common problems associated with the diagnosis of these neoplasms are summarized. Traditional veterinary histologic typing and grading of astrocytic tumors must be updated and supplemented with molecular data so that future studies directed toward therapeutic intervention and outcome can be optimized.     

Canine granulocytic ehrlichiosis (CGE) in Italy

Medical records of thirty-five consecutive cases of canine granulocytic ehrlichiosis (CGE) diagnosed cytologically in Central Italy in 1995-2000 were analysed retrospectively. Tick exposure was reported in 16 dogs (45.7%) and concurrent babesiosis in 19 dogs (54.3%). Ehrlichia-like inclusion bodies were found in neutrophils in a percentage varying from 0.5% to 11%. Frequently recorded clinical signs included anorexia (71.4%), lethargy (45.7%), conjunctivitis (31.4%), fever (25.7%), lameness (20%) and ataxia (20%). Among the 16 representative dogs in which protein, electrophoresis was performed, 10 (62.5%) showed high globulin levels and 6 (37.5%) had concurrent high total protein levels. During treatment with doxycycline, all associated symptoms, including those unusually described, such as pyoderma intertrigo, erythema, apparent blindness and oral papillomatosis, progressively disappeared in 31 (89%) out of 35 dogs. The efficacy of treatment was marked in dogs simultaneously treated twice with imidocarb dipropionate: among the 14 dogs in which a fast recovery was noted, 11 (80%) were concurrently affected by babesiosis and consequently treated with the specific medicament leading to excellent outcomes. The main conclusion is that CGE is present among dogs from Central Italy and should be included in the differential diagnosis of possible zoonotic agents affecting the canine population.     

Canine nodular dermatophytosis (kerion): 23 cases

Dermatophytosis is a common zoonotic disease, and one of its clinical presentations in the dog is nodular dermatophytosis (kerion). Because the infection is located within the dermis, routine diagnostic tests such as a Wood's lamp examination, microscopic examination of hair shafts for fungal elements and fungal culture can yield negative results. In such cases, histopathological examination with routine and special stains (periodic acid-Schiff, Gomori methenamine silver) is required to confirm the diagnosis. Nodular dermatophytosis in 23 dogs of different breed, age and sex with single or multiple nodules is described. Twelve dogs had a single nodule, and 11 dogs showed multiple lesions. Wood's lamp examination was negative in all cases. Microscopic examination of plucked hairs showed arthrospores in 8 of 23 cases. Skin scrapings in mineral oil looking for arthrospores and/or hyphae were positive in 12 cases. Impression smears of exudates were diagnostic in 21 of 23 cases (91%), showing arthrospores within fragments of hair shafts or free among neutrophils and macrophages (pyogranulomatous inflammation). Histopathology was performed in two cases. Fungal culture was positive for Microsporum canis in 16 dogs and for Microsporum gypseum in one dog. In six cases, the causative agent was not identified by fungal culture. All dogs were treated with systemic antifungal therapy and in eight cases with concurrent antibiotic therapy. Nodular dermatophytosis resolved in all dogs with the prescribed treatments within 4 to 8 weeks. Transmission to people or other pets in the home was not found.     

Experimental Detection of Canine Haemoglobin (Occult Blood) in Canine Faeces by Reversed Passive Latex Agglutination

A reversed passive latex agglutination test (RPLA) using anti-canine haemoglobin (Hb) antibody was developed for detecting bleeding in the lower digestive organs in dogs, and its applicability as a simple test for faecal occult blood was assessed. In Ouchterlony's gel immunodiffusion test, the anti-canine Hb antibody used to sensitize the latex reacted with canine Hb but not with Hbs, plasmas or meat extracts from pigs, goats, sheep, cattle, horses or chickens, or with fish extracts. Using latex sensitized with 50 µg/mg of anti-canine Hb IgG antibody, the lowest limit of detection for canine Hb was 21 µg/ml, and the latex reacted negatively with all test specimens other than canine Hb. In an in vitro experiment with a mixture of canine faeces and erythrocytes, the antigenicity of the Hb was found to undergo only very slight changes even when the specimens were allowed to stand for 12 h at room temperature. Hb could not be detected by RPLA in any of four successive faecal samples from three experimental dogs after infusion of autologous blood (5, 3 or 1 ml) into the stomach. In 3 other experimental dogs given an infusion of autologous blood (5, 3 or 1 ml) into the ascending colon, the presence of Hb was confirmed by RPLA in all four successive faecal samples obtained from those which received 5 or 3 ml of blood and in all except that obtained following the first defecation from the animal which had received 1 ml of blood.     

Canine serum protein patterns using high-resolution electrophoresis (HRE)

Serum protein values were determined in 26 healthy dogs using agarose gel electrophoresis (SPE), splitting the electrophoretic separation into six regions: albumin, alpha(1), alpha(2), beta(1), beta(2)and gamma globulins. High-resolution electrophoresis (HRE) was used to separate single proteins. Serum proteins from dogs (26 healthy and 20 affected by various diseases) were then characterized by electrophoretic immunofixation (IFE) and Sudan black staining on HRE film. Haemoglobin and normal canine plasma and serum were used to identify haptoglobin and fibrinogen, respectively.In the standard pattern, determined by HRE, the following proteins were identified: albumin, alpha(1)-lipoprotein (alpha(1)-region), haptoglobin and alpha(2)-macroglobulin (alpha(2)-region), beta -lipoprotein and C3 (beta(1)-region), transferrin and IgM (beta(2)-region), IgG (mostly in gamma -region and partly in beta(2)-region). The HRE pattern shown by healthy dogs could be compared with those of dogs affected by various diseases to obtain clinical information.     

Canine hemangiopericytoma: 23 cases (1967-1984)

The medical records of 23 histopathologically confirmed cases of canine hemangiopericytoma were reviewed. Ninety-one percent (21/23) of the dogs were 7 years old or older, and 70% (16/23) were female. Seventy-four percent (20/27) of the tumors developed on the extremities. Recurrence rates were 31% (5/16) with surgical excision only, and 60% (3/5) with surgical excision combined with radiotherapy. Tumor recurrence did not appear to be related to mitotic index. Metastasis was suspected in one of the dogs, but was not confirmed.     

Canine Ehrlichiosis (tropical canine pancytopenia): A review

Tropical canine pancytopenia (TCP), a disease of dogs caused by the rickettsial agent, Ehrlichia canis, is being recognized with increased frequency in many parts of the world. The brown dog tick, Rhipicephalus sanguineus, is an efficient vector of E. canis and transstadial transmission occurs. Infections persist and are characterized by rising antibody titers and hypergammaglobulinemia. Dogs cleared of infection with tetracycline are fully susceptible to reinfection with the homologous strain of E. canis and often develop severe disease. Experimental infections in beagle and German shepherd dogs have shown that severity of disease is related to the breed of dog. German shepherd dogs often develop a severe hemorrhagic syndrome 60 or more days following infection. Recent studies have shown that bone marrow hypoplasia is important in the pathogenesis of severe chronic TCP. Differences in response to infection may reflect underlying immunological defects, particularly in the cell-mediated system.     

The Canine Postamputation Pain (CAMPPAIN) initiative: a retrospective study and development of a diagnostic scale

ObjectiveTo develop a scale to diagnose and assess the severity of postamputation pain (PAP) in dogs.Study designSingle-center retrospective study.AnimalsA total of 66 dogs that underwent thoracic or pelvic limb amputation and 139 dogs that underwent tibial plateau leveling osteotomy (TPLO) at a veterinary teaching hospital.MethodsAn online survey regarding postoperative behavioral changes was sent to owners. Categorical, multiple-choice responses were entered into a univariable logistic regression model and tested for association with amputation using the Wald test. If p < 0.2, variables were forwarded to a multivariable logistic regression model for manual build. Model simplicity and predictive ability were optimized using the area under the receiver operating curve (AUROC) characteristic, and model calibration was assessed using the Hosmer–Lemeshow test. The selected model was converted to an integer scale (0–10), the Canine Postamputation Pain (CAMPPAIN) scale. Univariable logistic regression related each dog’s calculated score to the probability of PAP.ResultsMultivariable logistic regression identified four independent predictors of PAP (p < 0.05): 1) restlessness or difficulty sleeping, 2) episodes of panic or anxiety, 3) sudden vocalization, and 4) compulsive grooming of the residual limb. Score AUROC was 0.70 (95% confidence interval = 0.63–0.78) with good calibration (Hosmer–Lemeshow statistic p = 0.82). A score of 2 corresponded to a risk probability of 0.5. Taking a score ≥ 2 to indicate PAP, score specificity and sensitivity were 92.1% and 36.4%, respectively. When this score was used to diagnose PAP, prevalence was 36.4% (24/66) and 7.9% (11/139) in the amputation and TPLO groups, respectively.Conclusions and clinical relevancePostamputation pain is characterized by specific postoperative behaviors and appears to affect approximately one-third of canine amputees. The CAMPPAIN scale generated from these data could facilitate diagnosis, treatment and further study of PAP but requires external validation.     

Effect of Tamoxifen Citrate on Canine Immobilization (Disuse) Osteoporosis

The effect of tamoxifen citrate on bone mass in immobilization osteoporosis was studied in 11 growing dogs. Immobilization osteoporosis was induced by fiberglass cast immobilization of the right hindlimb for 28 days, while the left hindlimb served as a nonimmobilized control. Six dogs received tamoxifen citrate (1.5 mg/kg per os) once daily for 28 days; five dogs received no treatment. All dogs were euthanatized on day 28 and bone samples were collected. Bone mineral content of the distal tibial metaphysis of casted and uncasted limbs was measured by single photon absorptiometry. Immobilization resulted in a significant reduction in bone mass in the casted limb of untreated and tamoxifen-treated dogs. However, tamoxifen-treated dogs had less severe immobilization osteoporosis than untreated dogs. The calculated bone mass sparing effect of tamoxifen was 24.4%. Because of the complexity of pathologic bone remodeling, use of a single therapeutic agent may not be the optimal means of preventing bone loss associated with immobilization.