Bone marrow hypoplasia and intestinal crypt cell necrosis associated with fenbendazole administration in five painted storks

Five painted storks were treated with fenbendazole for 5 days for internal parasitism. Four birds died following treatment. Profound heteropenia was a consistent finding in all samples evaluated; additionally, the 1 surviving bird had progressive anemia. Consistent necropsy findings in the 4 birds that died were small intestinal crypt cell necrosis and severe bone marrow depletion and necrosis. Fenbendazole has been associated with bone marrow hypoplasia and enteric damage in mammals and other species of birds. The dosages of fenbendazole used in birds are often substantially higher than those recommended for mammals, which may contribute to bone marrow hypoplasia and intestinal crypt cell necrosis associated with fenbendazole administration in birds.     

Bone marrow necrosis in dogs: 34 cases (1996-2004)

OBJECTIVE: To identify the incidence, potential causes, and clinical and clinicopathologic features of bone marrow necrosis in dogs. DESIGN: Retrospective study. ANIMALS: 34 client-owned dogs. PROCEDURES: Reports of cytologic examinations of bone marrow specimens performed between 1996 and 2004 were reviewed. All reports that indicated the presence of necrosis, stromal disruption, phagocytic macrophages, individual cell necrosis, or myelofibrosis were evaluated further. RESULTS: Of 609 reports of bone marrow evaluations performed during the study period, 34 (5.6%) had evidence of bone marrow necrosis. Nine dogs had no evidence of associated diseases or drug or toxin exposure, and 25 dogs had associated disease conditions or drug exposures. All 9 dogs with idiopathic bone marrow necrosis were anemic (mean Hct, 14%), but only 3 had neutropenia, and 3 had thrombocytopenia. All 9 had myelofibrosis. Of the 25 dogs with associated disease conditions or drug exposures, only 14 (56%) had anemia (mean Hct, 33%). In addition, 14 (56%) had neutropenia and 18 (72%) had thrombocytopenia. Only 10 (40%) had myelofibrosis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that bone marrow necrosis may be common in dogs with hematologic disorders. In most dogs, bone marrow necrosis was associated with an underlying disease condition or drug exposure, but idiopathic bone marrow necrosis was also identified. Disease conditions that should increase suspicion of possible bone marrow necrosis include sepsis, lymphosarcoma, and systemic lupus erythematosus; drug exposures that should increase suspicion of possible bone marrow necrosis include chemotherapeutic agents, phenobarbital, carprofen, metronidazole, and mitotane.     

Hematologic effects of subcutaneous administration of recombinant human granulocyte colony-stimulating factor (filgrastim) in healthy alpacas

OBJECTIVE: To determine the effects of SC administration of filgrastim on cell counts in venous blood and bone marrow of healthy adult alpacas. ANIMALS: 10 healthy alpacas. PROCEDURES: Alpacas were randomly assigned to receive treatment with filgrastim (5 microg/kg, SC; n=5) or an equivalent volume of physiologic saline (0.9% NaCl) solution (5) once a day for 3 days. Blood samples were obtained via jugular venipuncture 1 day prior to treatment and once a day for 5 days commencing 24 hours after the first dose was administered. Complete blood counts were performed for each blood sample. Bone marrow aspirates were obtained from the sternum of each alpaca 48 hours before the first treatment was administered and 72 hours after the third treatment was administered. Myeloid-to-erythroid cell (M:E) ratio was determined via cytologic evaluation of bone marrow aspirates. RESULTS: In filgrastim-treated alpacas, substantial increases in counts of WBCs and neutrophils were detected within 24 hours after the first dose was administered. Band cell count and percentage significantly increased 24 hours after the second dose. Counts of WBCs, neutrophils, and band cells remained high 48 hours after the third dose. Red blood cell counts and PCV were unaffected. The M:E ratio also increased significantly after treatment with filgrastim. CONCLUSIONS AND CLINICAL RELEVANCE: Filgrastim induced rapid and substantial increases in numbers of circulating neutrophils and M:E ratios of bone marrow in healthy alpacas. Therefore, filgrastim may be useful in the treatment of camelids with impaired bone marrow function.     

A retrospective study of the incidence and the classification of bone marrow disorders in the dog at a veterinary teaching hospital (1996-2004)

BACKGROUND: An 8-year retrospective study was conducted to evaluate the prevalence and the classification of canine bone marrow disorders in a clinical pathology service at a university referral hospital. ANIMALS: Dogs evaluated for bone marrow disorders at a veterinary teaching hospital. HYPOTHESIS: A better understanding of the spectrum and the prevalence of canine bone marrow disorders can be achieved with a multiyear retrospective study. METHODS: Bone marrow aspirate smears, core biopsy specimens, and case records from 717 dogs were reviewed. RESULTS: Bone marrow specimens were first categorized based on the presence or the absence of a primary bone marrow disorder. Nondysplastic and nonmalignant pathologic changes were placed into 14 subcategories. Frequently observed pathologic disorders included nonregenerative immune-mediated anemia, pure red cell aplasia, bone marrow necrosis, myelofibrosis, and hemophagocytic syndrome. Dysmyelopoiesis (n = 61) was subcategorized into myelodysplastic syndromes (n = 27), and congenital (n = 1) and secondary (n = 33) dysmyelopoiesis. One hundred twenty-six cases of neoplasia were divided into acute leukemia (n = 46), chronic leukemia (n = 7), stage 5 malignant lymphoma (n = 28), multiple myeloma (n = 25), malignant histiocytosis (n = 11), metastatic mast-cell tumor (n = 3), sarcoma (n = 5), and carcinoma (n = 1). CONCLUSIONS AND CLINICAL IMPORTANCE: This study provides a general indication of the spectrum and the prevalence of canine bone marrow disorders at a referral center in North America.     

Primary pure red cell aplasia in dogs: 13 cases (1996-2000)

OBJECTIVES: To examine clinical features, laboratory test results, treatment, and outcome of dogs with pure red cell aplasia (PRCA). DESIGN: Retrospective study. ANIMALS: 13 dogs with severe nonregenerative anemia and bone marrow erythroid aplasia. PROCEDURES: Medical records of dogs determined to have PRCA on the basis of results of blood and bone marrow analysis between 1996 and 2000 were reviewed. Criteria for inclusion in the study were severe nonregenerative anemia (Hct < 20%; reticulocyte count < 1.0%), selective erythroid aplasia in bone marrow, and lack of underlying diseases that may have caused the anemia. RESULTS: Median age of dogs was 6.5 years. Females were significantly overrepresented. Median Hct was 10%, and median reticulocyte count was 0.1%. Direct Coombs' test results were negative for all dogs tested, and spherocytosis was evident in 2 dogs. All dogs were treated with prednisolone, and 2 dogs were treated with prednisolone and cyclophosphamide. Responses to treatment were complete, partial, and poor in 10, 1, and 2 dogs, respectively. Median time required to achieve an increase of 5% or more in Hct was 38 days, and median time to complete remission was 118 days. Of 10 dogs for which follow-up information was available, only 1 required long-term immunosuppressive treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with PRCA appear to respond readily to treatment with immunosuppressive drugs; however, hematologic responses may not be observed for weeks to months after initiation of treatment.     

Evaluation of monoclonal antibodies for identification of subpopulations of myeloid cells in bone marrow obtained from dogs

OBJECTIVE: To evaluate monoclonal antibodies that may be useful for immunophenotyping myeloid cells in bone marrow of dogs. SAMPLE POPULATION: Bone marrow specimens obtained from 5 dogs. DESIGN: Specimens were labeled with monoclonal antibodies that detected CD18, major histocompatability antigen class-II (MHC class-II), CD14, and Thy-1. Cells labeled with each of the antibodies were isolated by use of a fluorescence-activated cell sorter. Differential cell counts of sorted cells were used to determine cells that were labeled by each of the various antibodies. RESULTS: Myeloid cells labeled with anti-CD18 antibody included granulocytes, lymphocytes, and monocytes-macrophages. Immature and mature granulocytes were labeled. Lymphocytes, monocytes-macrophages, and eosinophils were labeled with anti-Thy-1 antibody. Cells labeled with anti-MHC-class II antibody included approximately 9% of bone marrow cells, which consisted almost exclusively of lymphocytes and monocytes-macrophages. Approximately 4% of bone marrow cells were labeled with anti-CD14 antibody, with > 90% of sorted cells being monocytes-macrophages. CONCLUSIONS AND CLINICAL RELEVANCE: Four monoclonal antibodies for use in detecting subpopulations of canine bone marrow cells were evaluated. These antibodies should be useful in differentiating the origin of leukemic cells in dogs.     

Hemophagocytic syndrome in dogs: 24 cases (1996-2005)

OBJECTIVE: To determine the frequency, potential causes, and clinical and clinicopathologic features of hemophagocytic syndrome in dogs. DESIGN: Retrospective study. ANIMALS: 24 client-owned dogs. PROCEDURES: Records for dogs in which diagnostic bone marrow specimens (including an aspiration smear and core biopsy material) were obtained from 1996 to 2005 were reviewed. Inclusion criteria were presence of bicytopenia or pancytopenia in the blood and > 2% hemophagocytic macrophages in the bone marrow aspirate. RESULTS: Of 617 bone marrow specimens evaluated, evidence of hemophagocytic syndrome was detected in 24 (3.9%). The Tibetan Terrier breed was overrepresented among dogs with hemophagocytic syndrome. Clinical signs associated with hemophagocytic syndrome included fever, icterus, splenomegaly, hepatomegaly, and diarrhea. Hemophagocytic syndrome was associated with immune-mediated, infectious, and neoplastic-myelodysplastic conditions and also occurred as an idiopathic condition. Overall, dogs with infection-associated hemophagocytic syndrome had better 1-month survival rates than dogs with immune-associated and idiopathic hemophagocytic syndrome. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that hemophagocytic syndrome may occur more frequently in dogs than has previously been suspected on the basis of the paucity of reported cases. Although most dogs had definable underlying disease conditions, idiopathic hemophagocytic syndrome was also identified. Hemophagocytic syndrome of any cause is potentially life-threatening; however, the prognosis should be adjusted on the basis of the associated disease process and potential for successful treatment.     

Diagnostic use of cytologic examination of bone marrow from dogs with thrombocytopenia: 58 cases (1994-2004)

OBJECTIVE: To determine the diagnostic use of cytologic examination of bone marrow from dogs with thrombocytopenia. DESIGN: Retrospective case series. ANIMALS: 58 dogs with thrombocytopenia. PROCEDURES: Medical records were searched and reviewed for dogs with thrombocytopenia. Dogs that had thrombocytopenia and cytologic examination of bone marrow were included in the study. Dogs with other hematologic abnormalities, with a previous diagnosis of hematopoietic neoplasia, or that had previous treatment with cytotoxic drugs were excluded. Bone marrow cytologic findings were reviewed. Results were compared between dogs with severe thrombocytopenia (< 20,000 platelets/microL) and dogs with mild to moderate thrombocytopenia (20,000 to 200,000 platelets/microL). RESULTS: 58 dogs met the inclusion criteria. Of 55 dogs with diagnostic bone marrow aspirates, 36 had severe thrombocytopenia. Cytologic evaluation of bone marrow did not reveal substantial nonmegakaryocytic bone marrow abnormalities or result in a definitive diagnosis in any of these dogs. Nineteen dogs with mild to moderate thrombocytopenia had diagnostic bone marrow aspirates. Bone marrow cytologic findings revealed nonmegakaryocytic abnormalities in 4 of these dogs. Significantly fewer dogs with severe thrombocytopenia had abnormalities identified on cytologic examination of bone marrow, compared with dogs with mild to moderate thrombocytopenia. CONCLUSIONS AND CLINICAL RELEVANCE: Cytologic examination of bone marrow is unlikely to provide specific diagnostic or prognostic information in dogs with severe thrombocytopenia.     

Persistence of serum antibodies to Sarcocystis neurona in horses moved from North America to India

BACKGROUND: The study reported here was undertaken to assess the presence of antibodies to Sarcocystis neurona in the serum of horses of North American origin that had been relocated for 1 year or more to India (ie, outside of the known endemic areas for S. neurona). HYPOTHESIS: The presence or absence of such antibodies should provide information concerning the persistence of such antibodies, or support the presence of chronic infection, or both. ANIMALS: A total of 228 Thoroughbred horses were sampled in India, of which 86 were of North American origin that had been in India between 1 and 13 years, 124 were Indian-born horses that had never been out of India, 8 were of Irish origin, 8 were of English origin, and 2 were originally from France. METHODS: Sera were tested using established western blot analysis. RESULTS: Of the Indian-born horses, 0.8% were test positive, and of the North American horses, 42% were test positive. All of the English and Irish horses were test negative, and the 2 French horses were test positive. CONCLUSIONS AND CLINICAL IMPORTANCE: These data indicate that antibodies against S. neurona can be detected for many years after horses have been removed from an endemic area and that this may be attributable to long half-life of the antibodies or to chronic infection and ongoing antibody production, or both.     

Evaluation of clinicopathologic features, response to treatment, and risk factors associated with idiopathic neutropenia in dogs: 11 cases (1990-2002)

OBJECTIVE: To evaluate the clinicopathologic features, response to treatment, and risk factors associated with idiopathic neutropenia in dogs. DESIGN: Retrospective case series. ANIMALS: 11 dogs. PROCEDURES: Medical records of dogs with idiopathic neutropenia were reviewed. Signalment, history, clinical signs, and response to treatment were recorded and compared with that in dogs with neutropenia attributable to known causes and to dogs without neutropenia (controls). RESULTS: Compared with dogs with neutropenia attributable to known causes, dogs with idiopathic neutropenia had lower neutrophil counts and were younger. When compared with control dogs, age < 4 years was identified as a risk factor for developing idiopathic neutropenia. In all dogs with idiopathic neutropenia, remission of neutropenia occurred within 18 days after administration of prednisone (2 to 4 mg/kg [0.9 to 1.8 mg/lb], PO, daily) and no serious complications or infections developed. CONCLUSIONS AND CLINICAL RELEVANCE: An immune-mediated pathogenesis should be considered for dogs with idiopathic neutropenia in which the cause is not known. Severe neutropenia and young age were significantly associated with idiopathic neutropenia in dogs. Prognosis appeared to be excellent with prednisone treatment.     

Disseminated histoplasmosis in an African pygmy hedgehog

CASE DESCRIPTION: A 2-year-old captive-bred sexually intact female African pygmy hedgehog (Atelerix albiventris) was evaluated because of vague signs of illness including inappetence, weakness, lethargy, and weight loss over a 20-day period. CLINICAL FINDINGS: Abnormalities detected via initial clinicopathologic analyses included anemia, thrombocytopenia, leukopenia, hypoproteinemia, and hypoglycemia. Results of a fecal flotation test were negative. Three weeks after the initial evaluation, splenomegaly was detected via palpation and ultrasonography. TREATMENT AND OUTCOME: The hedgehog was treated with broad-spectrum antibacterial agents, resulting in an initially favorable response. Fenbendazole was also administered against possible occult parasitic infestation. After 3 weeks of illness, the hedgehog's condition had worsened and supportive care and administration of additional antibacterial agents were instituted. The hedgehog died, and pathologic examinations revealed severe splenomegaly; granulomatous infiltrates were evident in multiple organs, and Histoplasma capsulatum yeasts were detected intralesionally. CLINICAL RELEVANCE: Histoplasmosis can develop in a wide range of mammalian species. African pygmy hedgehogs are becoming increasingly popular as exotic pets, and vague signs of illness and splenomegaly are often attributed to hemolymphatic malignancies, which are somewhat common in this species. Practitioners should be aware that similar clinical signs may be associated with histoplasmosis in these animals. Although the hedgehog of this report was confined indoors, it originated from an area where histoplasmosis was endemic; this indicates that the disease should be included as a differential diagnosis for hedgehogs that develop vague signs of illness and are known to originate from such geographic regions.     

Role of platelet activating factor in development of thrombocytopenia and neutropenia in dogs with endotoxemia

OBJECTIVE: To determine the role of platelet activating factor (PAF) in lipopolysaccharide (LPS)-induced thrombocytopenia and neutropenia in dogs. ANIMALS: 42 dogs. PROCEDURES: Blood samples were obtained from dogs given LPS (40 microg/kg of body weight; n = 16), PAF (1 microg/kg; 6), PAF (5 microg/kg/h for 90 minutes; 4), or physiologic saline (0.9% NaCl) solution (0.1 ml/kg/h for 90 minutes; 3) IV to monitor changes in blood cell counts, using automated counters and blood smears stained with Giemsa. Blood samples were also obtained from dogs given LPS (40 microg/kg) that had (n = 5) or had not (6) been treated beforehand with TCV-309, a potent PAF antagonist. Concentration of PAF in blood was determined by use of 125I-radioimmunoassay in dogs given LPS at 1 mg/kg (n = 3) and 40 microg/kg (9). RESULTS: Thrombocytopenia and neutropenia were found in all dogs except those given saline solution. The LPS-induced thrombocytopenia was significantly suppressed by prior treatment with TCV-309. The PAF concentrations increased markedly 1 hour after injection of 1 mg/kg of LPS and increased slightly but significantly 10 minutes after injection of 40 microg/kg of LPS. CONCLUSION AND CLINICAL RELEVANCE: PAF plays an important role in the development of LPS-induced thrombocytopenia and neutropenia in dogs. Control of PAF production, PAF-induced effects, or both may be important in the treatment of dogs with gram-negative bacterial infections and associated thrombocytopenia and neutropenia.     

Immune-mediated erythroid and megakaryocytic aplasia in a cat

CASE DESCRIPTION: A 6-month-old domestic shorthair cat was evaluated because of acute lethargy. CLINICAL FINDINGS: Severe nonregenerative anemia and thrombocytopenia were identified. Cytologic examination of a bone marrow aspirate revealed selective erythroid and mega-karyocytic aplasia and a high number of apparently normal small lymphocytes. Infectious agents implicated in feline hematologic disorders were excluded on the basis of serologic tests or PCR amplification, including FeLV, Ehrlichia canis, Anaplasma phagocytophilum, Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, and Candidatus Myco-plasma turicensis. TREATMENT AND OUTCOME: A 10-day course of prednisolone administration did not improve the hematologic disorder. Administration of human polyclonal immunoglobulins preceded increased reticulocyte count by 3 days. A second bone marrow examination confirmed restoration of erythroblasts and megakaryocytes. After 1 relapse, the disease was successfully controlled with prednisolone for > 3 years. CLINICAL RELEVANCE: Immune-mediated bone marrow aplasia is rare in cats and usually affects only erythrocyte progenitors. Concomitant involvement of erythroid and megakaryocytic cell lines can be successfully treated via immunosuppressive therapy. Human immunoglobulins seem to be well tolerated in cats; however, proof of a beneficial effect requires further study.     

Idiopathic pure red cell aplasia and nonregenerative immune-mediated anemia in dogs: 43 cases (1988-1999)

OBJECTIVE: To examine clinical features, laboratory test results, treatment, and outcome of dogs with pure red cell aplasia (PRCA) and idiopathic nonregenerative immune-mediated anemia (NRIMA). DESIGN: Retrospective study. ANIMALS: 43 dogs with severe nonregenerative anemia. PROCEDURE: Medical records of dogs determined to have PRCA, NRIMA, or ineffective erythropoiesis on the basis of bone marrow analysis between 1988 and 1999 were reviewed. Criteria for inclusion were > or = 5-day history of severe nonregenerative anemia (Hct < 20%; < 60.0 x 10(3) reticulocytes/microliter) with no underlying diseases. Information was retrieved on signalment, clinical signs, laboratory test results, treatment, and outcome. RESULTS: Median age of the dogs was 6.5 years. Spayed females and Labrador Retrievers were significantly overrepresented. Median Hct was 11% with no evidence of regeneration (median, 1.5 x 10(3) reticulocytes/microliter). Direct Coombs' test results were positive in 57% of dogs. Biochemical abnormalities included hyperferremia and high percentage saturation of transferrin. Bone marrow findings ranged from PRCA (5%) to erythroid hyperplasia (55%). Myelofibrosis was common. Dogs were treated with immunosuppressive drugs and the response was complete, partial, and poor in 55, 18, and 27% of the dogs, respectively. Mortality rate was 28%. CONCLUSIONS AND CLINICAL RELEVANCE: An immune-mediated pathogenesis should be considered in dogs with severe, nonregenerative anemia, normal WBC and platelet counts, hyperferremia, mild clinical signs, and no evidence of underlying disease. Bone marrow findings range from the rare PRCA to erythroid hyperplasia. Myelofibrosis is often detected in affected dogs and may prevent bone marrow aspiration.     

Use of multigeneration-family molecular dog leukocyte antigen typing to select a hematopoietic cell transplant donor for a dog with T-cell lymphoma

CASE DESCRIPTION: A 7-year-old Golden Retriever was examined because of anorexia, lethargy, vomiting, and gradual weight loss. CLINICAL FINDINGS: Splenomegaly, pancytopenia, high serum calcium concentration, and high alkaline phosphatase activity were detected. Magnetic resonance imaging revealed an enlarged mesenteric lymph node and increased signals from the bone marrow of the ilium and vertebral bodies. Histologic examination and immunophenotyping of biopsy specimens confirmed a stage V (b) T-cell malignant lymphoma. TREATMENT AND OUTCOME: Clinical remission was attained by use of 2 chemotherapy cycles, followed by an allogeneic hematopoietic cell transplant performed at 18 weeks after diagnosis. A donor was identified by molecular dog leukocyte antigen typing methods. The patient was conditioned with 2 fractions of 4 Gy total body irradiation delivered 3 hours apart at 7 cGy/min, followed by an IV infusion of recombinant canine granulocyte colony-stimulating factor mobilized leukapheresis product and postgrafting immunosuppression with cyclosporine. Chimerism analyses revealed full donor engraftment that has been maintained for at least 58 weeks after transplant. Remission has been confirmed by normal results of serum thymidine kinase assays and the absence of peripheral blood clonal T-cell receptor gene rearrangements. CLINICAL RELEVANCE: Systemic chemotherapy induces remissions; however, most dogs succumb to disease recurrence because of multidrug resistance. Outcome of allogeneic hematopoietic cell transplantation in dogs can be excellent because of improved donor-recipient selection by use of molecular dog leukocyte antigen typing, compared with early attempts, and better prevention of graft versus host disease, better supportive care, and substitution of peripheral blood mononuclear cells for bone marrow.     

Prevalence of Salmonella spp in cloacal, fecal, and gastrointestinal mucosal samples from wild North American turtles

OBJECTIVE: To determine prevalence of Salmonella spp in samples collected from wild North American turtles. ANIMALS: 94 wild North American turtles of 6 species in 2 genera. DESIGN: Prospective microbiologic study. PROCEDURES: A convenience sample of wild North Carolina turtles admitted to a veterinary college was evaluated for Salmonella spp by use of standard techniques via microbiologic culture of cloacal swab and fecal samples. Gastrointestinal mucosa samples were also collected at necropsy from turtles that died or were euthanized. Cloacal swab samples were also collected from wild pond turtles for bacteriologic culture. Controls were established by use of wild-type Salmonella Typhimurium LT2. RESULTS: 94 turtles were tested for Salmonella spp; Salmonella spp were not detected in any sample. By use of a pathogen-prevalence and sample-size table, the true prevalence of Salmonella spp was estimated as < 5%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that wild turtles in central North Carolina may not be active shedders or carriers of Salmonella spp. Despite this 0% prevalence of infection, proper hygiene practices should be followed when handling wild turtles.     

Dimensions and histologic characteristics of the small intestine of dogs during postnatal development

OBJECTIVE: To quantify dimensions of the small intestine of dogs and describe changes in histologic characteristics of the mucosa during postnatal development. SAMPLE POPULATION: Gastrointestinal tract tissues obtained from 110 Beagles (15 adult females and 95 puppies of both sexes). PROCEDURE: Several variables (length, total weight, mucosal weight, and nominal surface area) of the small intestine were measured in puppies at birth but before suckling; 1 day after birth and subsequent suckling, 21, 42, and 63 days after birth, and in the adult dams of the puppies. Tissue structure was examined and quantified at each time point by use of routine histologic examination and ocular micrometry of formalin-fixed specimens stained with H&E. RESULTS: Small intestinal dimensions increased throughout development with the greatest proportional changes during the first day after birth and onset of suckling. Villus height decreased during suckling but had consistent values from 42 days after birth to maturity, whereas crypt depth increased from birth to maturity. Vacuolated enterocytes were evident from birth to 21 days but not thereafter. CONCLUSIONS AND CLINICAL RELEVANCE: Increases in intestinal dimensions provide growing dogs with a greater capacity for digestion and absorption. Changes in mucosal architecture and cell populations coincided with shifts in dietary inputs. These findings may assist in the diagnosis of small intestinal diseases and nutritional responses during growth and development of dogs.     

Giardia infection in animals in Poznań Zoo

One hundred and eighty-four faecal samples from 170 animals of 82 different species in Poznań Zoo were examined with direct wet mounts in physiological saline and permanent smears stained with iron-haematoxylin. Giardia spp. cysts were found in one chimpanzee, four marmosets, two North American porcupines, a European wild cat and a serval. The infection in the porcupines was very intense and resistant to metronidazole treatment.     

ABCB1-1Delta polymorphism can predict hematologic toxicity in dogs treated with vincristine.

BACKGROUND: Dogs that harbor the naturally occurring ABCB1-1Delta polymorphism experience increased susceptibility to avermectin-induced neurological toxicosis as a result of deficient P-glycoprotein function. Whether or not the ABCB1-1Delta polymorphism affects susceptibility to toxicity of other P-glycoprotein substrate drugs has not been studied. HYPOTHESIS: Dogs that possess the ABCB1-1Delta mutation are more likely to develop hematologic toxicity associated with vincristine than ABCB1 wild-type dogs. ANIMALS: Thirty-four dogs diagnosed with lymphoma were included in this study. METHODS: Cheek swab samples were obtained from dogs diagnosed with lymphoma that were to be treated with vincristine. DNA was extracted from cheek swabs and the ABCB1 genotype was determined. Hematologic adverse drug reactions were recorded for each dog and graded according to the Veterinary Comparative Oncology Group's criteria for adverse event reporting (Consensus Document). In order to avoid possible bias, ABCB1 genotype results for a particular patient were not disclosed to oncologists until an initial adverse event report had been submitted. RESULTS: Dogs heterozygous or homozygous for the ABCB1-1Delta mutation were significantly more likely to develop hematologic toxicity, specifically neutropenia (P= .0005) and thrombocytopenia (P= .0001), after treatment with vincristine than ABCB1 wild-type dogs. CONCLUSIONS AND CLINICAL IMPLICATIONS: At currently recommended dosages (0.5-0.7 mg/M(2)), vincristine is likely to cause hematologic toxicity in dogs with the ABCB1-1Delta mutation, resulting in treatment delays and unacceptable morbidity and mortality. Assessing the ABCB1-1Delta genotype before vincristine administration and decreasing the dosage may prevent toxicity and treatment delays resulting from neutropenia or thrombocytopenia.     

Efficacy of radiation therapy for incompletely resected grade-III mast cell tumors in dogs: 31 cases (1987-1998)

OBJECTIVE: To determine the efficacy (durations of remission and survival) of an alternating-day radiation protocol for incompletely excised histologic grade-III solitary mast cell tumors (MCTs) in dogs. DESIGN: Retrospective study. ANIMALS: 31 dogs. PROCEDURE: Radiation (52 Gy in an 18-fraction alternating-day protocol) was delivered to an area bordered by margins > or = 3 cm around the surgical scar and to the associated local-regional lymph nodes. Dogs were not given chemotherapeutic agents concurrently or after radiation. Information on signalment, duration of remission, and survival time was obtained from medical records. RESULTS: Median and mean durations of remission were 27.7 and 17.0 months, respectively (range, 1 to 47 months). Median and mean durations of survival were 28 and 20 months, respectively (range, 3 to 52 months). Dogs with tumors located on the skin of the pinna, perineum, and prepuce had a median duration of remission greater than dogs with tumors located at other sites (27.7 and 14.4 months, respectively). Dogs with tumors < or = 3 cm in maximum diameter before surgery survived longer than dogs with tumors > 3 cm (31 and 24 months, respectively). The remission rate was 65% and survival rate was 71% at 1 year after treatment. Sixteen dogs that were euthanatized had complications associated with local-regional tumor progression. Systemic metastases to liver, spleen, intestine, and bone marrow were detected in 1 dog. CONCLUSIONS AND CLINICAL RELEVANCE: Without further treatment, incompletely excised grade-III mast cell tumors have high local-regional recurrence; local-regional treatment with radiation may effectively be used to manage many such tumors.