Conjunctival lymphoma: immunophenotype and outcome in five dogs and three cats

Conjunctival lymphoma is well documented in the medical literature, but veterinary reports are few. We report five cases of canine lymphoma, and three of feline in which the presenting sign was conjunctival involvement. All animals were in apparently good health at the time of presentation, and attended the referring clinic because of conjunctival disease. One dog showed generalized lymphadenopathy at presentation, although the ocular lesion was the reason for consultation, but all other patients were well with no detectable disease beyond the eye. All cats were presented for their ocular disease. All dogs were confirmed to have T‐cell tumors, although the histological appearance of these was variable. In contrast, all cats had B‐cell tumors. Referring clinicians and owners were contacted for follow‐up information. Three dogs had been euthanased within 6 months of diagnosis for deterioration of general health. The remaining two were alive and showed no signs of systemic disease. Two cats had good survival following diagnosis, the other died of lesions that may not be related.     

Clinical and pathological classification of canine intraocular lymphoma

The objectives of this retrospective study of 100 dogs with intraocular lymphoma were to describe the histomorphologic and immunohistochemical features of canine intraocular lymphoma, determine the proportion of cases with presumed solitary ocular lymphoma (PSOL) compared to multicentric disease, and assess the clinical outcomes of these patients. Selected cases from Penn Vet Diagnostic Laboratory and Comparative Ocular Pathology Lab of Wisconsin (2004–2015) were evaluated and subtyped using the WHO classification system. Peripheral T‐cell lymphoma and diffuse large B‐cell lymphoma were the two most common subtypes. Questionnaires were distributed to the referring veterinarians and veterinary ophthalmologists inquiring about clinical signs at time of enucleation, staging, patient outcome, treatment, and disease progression. Cases were categorized as PSOL if only ocular involvement was noted at the time of diagnosis based on the clinical staging criteria. The majority of cases (61%) did not have systemic involvement at the time of diagnosis, and these cases did not progress postoperatively. Median survival time (MST) was significantly higher for the presumed solitary intraocular cases: 769 vs. 103 days, hazard ratio of 0.23 (95% CI: 0.077–0.68). The subtype of lymphoma did not affect survival time. The results of this study suggest two significant points of clinical interest: the majority of dogs (61%) presented without signs of systemic involvement of lymphoma at the time of enucleation, and dogs with only ocular involvement showed no disease progression postenucleation.     

A retrospective evaluation of lomustine (CeeNU) in 32 treatment naïve cats with intermediate to large cell gastrointestinal lymphoma (2006–2013)

Multi‐drug chemotherapy protocols for feline lymphoma have demonstrated variable efficacy and tolerability. In phase I trials, lomustine has demonstrated efficacy for cats with lymphoma though its use for treatment naïve feline intermediate/large cell gastrointestinal (GI) lymphoma remains unknown. This study evaluated the efficacy and tolerability of lomustine for the treatment of feline GI lymphoma. Thirty‐two cats with histologically or cytologically confirmed intermediate/large cell GI lymphoma were evaluated retrospectively. Factors assessed included clinical signs, hematologic/biochemical parameters and use of l ‐asparaginase at induction. A response rate of 50% (16/32), with median duration of response of 302 days (range 64–1450 days), was found. Median progression‐free interval was 132 days (range 31–1450 days), with overall median survival time of 108 days (range 4–1488 days). History of hyporexia, presence of anaemia and dose of lomustine were significantly associated with progression‐free survival. Overall, lomustine is a well‐tolerated and effective treatment for feline GI lymphoma.     

Calponin expression and myoepithelial cell differentiation in canine, feline and human mammary simple carcinomas

Calponin is a 34‐kDa smooth muscle‐specific protein that has been shown to be a highly sensitive marker of myoepithelial cells in canine, feline and human mammary tissue and tumours. The expression of calponin was studied in 15 canine, 32 feline and 28 human simple mammary carcinomas using a monoclonal mouse antihuman calponin antibody and the avidin–biotin peroxidase complex (ABC) immunohistochemical technique. Calponin expression was compared with the expression of cytokeratin 14, a marker of normal mammary myoepithelial cells in the three species. Four different types of calponin‐positive cells were identified: (1) Type 1: cytokeratin‐14‐positive pre‐existing myoepithelial cells forming a continuous layer with images of focal disruptions; (2) Type 2: cytokeratin‐14‐positive isolated nests of fusiform, polygonal or round cells without atypia; (3) Type 3: cytokeratin‐14‐positive atypical cells indistinguishable from non‐reactive atypical cells, which should have never been detected in haematoxylin and eosin‐stained sections and (4) Type 4: cytokeratin‐14‐negative stromal fusiform cells around the neoplastic growth or cell nests, identified as myofibroblasts. Calponin‐negative and cytokeratin‐14‐positive atypical neoplastic cells were observed in three canine, 28 feline and two human carcinomas. The latter were indicative of altered expression of high‐molecular‐weight cytokeratins in luminal epithelial‐type simple carcinomas. Our findings show that calponin is a good marker of myoepithelial cell differentiation in feline, human and, particularly, canine simple carcinomas. The high number (six out of 15) of canine tumours with type 3 cells points to the need of both introducing calponin examination in the routine diagnostic schedule and performing further studies on its prognostic significance.     

Feline Hodgkin's-like lymphoma: 20 cases (1992-1999)

We identified 20 cases of feline lymphadenopathy that conform to many clinical and histologic manifestations of human Hodgkin's disease. Histologic subtypes encountered included lymphocyte predominance (nine cases), mixed cellularity (nine cases), and nodular sclerosis (two cases). Two cases were not easily classified; fibrous bands were present, but the absence of nodules supported a subclassification of mixed cellularity Hodgkin's disease. Immunohistochemical staining of the tissues using antibodies against the pan T-cell antigen CD3, the human B-lymphocyte antigen 36 (BLA.36), the pan B-lymphocyte and plasma cell marker CD79a, and a myeloid antigen (MAC387) confirmed the phenotypic heterogeneity of the tumor. Classic Reed-Sternberg (RS) cells and mononuclear, multinucleate, and lacunar cell variants did not stain with any of the antibodies used. In contrast, lymphohistiocytic RS variants (L+H cells) reacted positively to BLA.36 and CD79a B-cell markers. Eighteen of 20 affected cats were > or = 6 years of age (range, 1-14 years). A sex predilection could not be identified. These findings support the existence of Hodgkin's-like lymphoma in the cat. Proper identification of this disease in the cat will enable further characterization of clinical features and biologic behavior to determine whether there are significant differences in the treatment and prognosis of feline Hodgkin's-like lymphoma compared with non-Hodgkin's lymphoma.     

Immunohistochemical analysis of cyclin A, cyclin D1 and P53 in mammary tumors, squamous cell carcinomas and basal cell tumors of dogs and cats

The involvement of cyclin A, cyclin D1 and p53 proteins in canine and feline tumorigenesis was analyzed immunohistochemically. In the present study, a total of 176 cases were examined, among which there were 108 canine cases (75 mammary lesions, 16 squamous cell carcinomas and 17 basal cell tumors) and 68 feline cases (43 mammary lesions, 20 squamous cell carcinomas and 5 basal cell tumors). Speckled nuclear staining for cyclin A was observed in 19/38 (50%) canine malignant mammary tumors and 18/37 (48.6%) feline mammary carcinomas, while this was not seen in benign mammary tumors of either dogs or cats. Marked intense nuclear cyclin A staining was seen in 7/16 (43.8%) canine squamous cell carcinomas and 18/20 (90.0%) feline squamous cell carcinomas. Only 3/17 (17.6%) canine basal cell tumors showed slight and scattered staining for cyclin A. Expression of cyclin D1 was very rare in both canine and feline tumors. Nuclear staining of p53 was found in 7/37 (18.9%) feline mammary carcinomas. Intense immunoreactivity for p53 was found in 6/16 (37.5%) canine squamous cell carcinomas and 8/20 (40%) feline squamous cell carcinomas. These results suggest that cyclin A may have a role in the proliferation of canine malignant mammary tumors, feline mammary carcinomas and squamous cell carcinomas of dogs and cats, and p53 may associate with the tumorigenesis of feline mammary carcinomas and squamous cell carcinomas of dogs and cats.     

Detection of monoclonality in intestinal lymphoma with polymerase chain reaction for antigen receptor gene rearrangement analysis to differentiate from enteritis in dogs

The diagnosis of canine intestinal lymphoma by morphological examination is challenging, especially when endoscopic tissue specimens are used. The utility of detection of antigen receptor gene rearrangement by polymerase chain reaction (PARR) in canine lymphoma has been well established, but its usefulness to distinguish enteritis and intestinal lymphoma remains unclear. In this retrospective study we assessed clonality of 29 primary canine intestinal lymphoma, 14 enteritis and 15 healthy control cases by PARR analysis, using formalin‐fixed, paraffin‐embedded full‐thickness tissue specimens. We could detect monoclonal rearrangements in 22 of 29 canine intestinal lymphomas [76%; 95% confidence interval (CI) 56–90%] and polyclonal rearrangements in all of the enteritis and healthy control cases (100%; CI 88–100%). We revealed a predominance of T‐cell phenotype compared to B‐cell phenotype (85%; CI 65–96% and 15%; CI 4–35%, respectively). We showed that PARR analysis contributes to differentiation of canine intestinal lymphoma from enteritis and to phenotyping of lymphomas.     

Lymphoma (malignant lymphoma, lymphosarcoma) in the dog

This report describes seven cases of canine lymphoma involving three German shepherd dogs, two boxers and two mongrels with a male to female ratio of 1–3 to 1. Their mean age and body weight was four years (range 1–5 to 8) and 31 kg (range 21 to 40), respectively. Six of the animals were euthanased at their owner's request and one died. Excessive lymph node enlargement, splenomegaly, hepatomegaly, blood lymphocytosis and proteinuria were the most striking clinical and clinicopathological findings. All the cases except one presented systemic signs and three developed secondary leukaemia because of bone marrow involvement. The anatomical types were classified according to the World Health Organization's criteria as thymic (one dog) and generalised (six dogs) and the clinical stage as IV (four dogs) and V (three dogs). Extranodal lymphomas involving the kidneys, meninges and the alimentary tract were seen in two cases. Histologically, the lymphomas were classified as lymphoblastic in four dogs, and in the remaining animals as lymphoblastic with plasmacytoid differentiation, lymphocytic with plasmacytoid differentiation, and poorly differentiated (stem cell) with one type appearing in each dog.     

Clinical and histopathological classification of feline intraocular lymphoma

This retrospective study aimed to describe and classify cats with intraocular lymphoma, determine the proportion of cases with presumed solitary ocular lymphoma (PSOL) compared with ocular manifestations of multicentric disease and assess the clinical outcomes of these patients. One hundred seventy‐two cases identified through biopsy submissions were reviewed histologically; 163 of these cases were subtyped according to the WHO classification system. Cases were categorized as having PSOL or ocular lymphoma with suspected systemic involvement (SSI) based on submission forms and follow‐up data. The majority of cases exhibited concurrent uveitis (75%) and secondary glaucoma (58%). Diffuse large B‐cell lymphoma was the most common subtype (n = 86; 53%), followed by peripheral T‐cell lymphoma (n = 44; 27%). Other subtypes included anaplastic large T‐ (n = 8; 5%) and B‐cell (n = 4; 2.5%) lymphomas, and 15 cases (9%) were negative for all immunohistochemical markers. In sixty‐nine cases (40%), adequate clinical data and sufficient survival data were obtained to distinguish PSOL from SSI. PSOL comprised the majority of cases (64%), while 36% had SSI. When covarying for age at diagnosis, the median survival time was significantly higher (P = 0.003) for cases of PSOL (154 days) versus those with SSI (69 days); hazards ratio of 0.47 for PSOL (95% CI: 0.241‐0.937). The subtype of lymphoma did not affect survival time. Cats with PSOL represent a greater proportion of the disease population, and this subset of cats with intraocular lymphoma has a better clinical outcome.     

Epidemiological,pathological and immunohistochemical aspects of 125 cases of feline lymphoma in Southern Brazil

A retrospective study compiling cases of feline lymphoma diagnosed during 12 years (2004‐2016) in Southern Brazil was performed. A total of 125 cases of lymphoma diagnosed in cats were reviewed, and information including age, breed, sex and tumour topography were collected. FeLV and FIV immunohistochemical tests were performed, as well as immunophenotyping of lymphomas. The alimentary form represented the most common presentation (42/125), followed by mediastinal lymphoma (35/125). Out of 125 cases, 79 presented positive retroviral immunostaining in tumour tissue (52 FeLV alone, 14 FIV alone and 13 presented FIV and FeLV co‐infections), 66/125 of the cases were of T‐cell origin and 59/125 of the cases were of B‐cell origin. The median age of cats with T‐cell lymphoma was 120 months (10‐240 months), and 60 months (6‐204 months) for cats with B‐cell lymphoma. The most frequent alimentary tumour presentation was the enteropathy‐associated T‐cell lymphoma (type 1), and the major type of mediastinal tumour observed was diffuse large B‐cell lymphoma. Considering only mediastinal and alimentary lymphomas (n = 77), the prevalence of mediastinal lymphoma in FeLV‐positive cats was 2.21 times higher than the prevalence of this type of tumour in FeLV‐negative cats (P = .036). Mediastinal lymphoma was more frequently observed in younger cats, and the prevalence of mediastinal tumours in these animals was 3.06 times higher than the prevalence of this tumour form in old cats (P = .0125). The present study indicates that retroviral infections still play an important role in the development of feline lymphomas in southern Brazil.     

Surgical treatment of epibulbar melanocytomas by complete excision and homologous corneoscleral grafting in dogs: 11 cases

Objective The aim of the study was to evaluate the efficacy, outcome, and complications following penetrating sclerokeratoplasty and frozen homologous corneoscleral grafting for the management of extensive canine epibulbar melanocytomas. Methods Medical records of canine patients treated at three different veterinary hospitals between 1999 and 2010 were reviewed. Signalment, location and extent of melanocytomas, recurrence rate, and early and late complications were reported. Patients were re‐examined postoperatively to provide follow‐up information. Results Patients included one intact male, three castrated males, six intact females, and one spayed female, with a median age of 5 years (range, 3–9). German Shepherds were overrepresented. Tumors extended from 2 to 4 clock hours at the limbus and up to 17 mm from clear cornea to globe equator. One case showed iridocorneal angle invasion; corneal involvement was present in all cases, and lipid keratopathy was present in four cases. In two cases, there was incomplete resection owing to tumor extent. Follow‐up time ranged from 3 to 72 months (median, 17 months), with one case of intraocular tumor progression. Early complications included anterior uveitis (11/11), intracameral fibrin (5/11), hyphema (4/11), corneal edema (4/11), exuberant corneal granulation tissue (2/11), focal retinal edema (1/11), dyscoria (1/11), and partial suture dehiscence (1/11). Late complications included corneal fibrosis and/or pigmentation (11/11), faint anterior cortical cataracts (3/11), and lipid keratopathy (1/11). Vision was retained in all cases. Conclusions This technique offers a surgically challenging but effective treatment for extensive epibulbar melanocytomas. In this case series, complications were mild and transient, with preservation of ocular anatomy and function.     

Ocular manifestation of lymphoma in newly diagnosed cats

Ocular manifestations of lymphoma are described in humans and dogs but rarely in cats. In this prospective study, cats with newly diagnosed and treatment‐naïve lymphoma were evaluated concerning clinical stage and ophthalmologic findings. Twenty‐six cats were included. In 12 cats (48%), ocular changes were documented. Uveitis anterior and posterior were predominant findings, being present in 58% of affected individuals. Other findings included exophthalmos, corneal surface lesions and chemosis. Eight cats received chemotherapy, two of which had ocular involvement. In these two cats, a complete remission of an anterior and a partial remission of a posterior uveitis were documented. Due to the detection of ocular involvement, a stage migration from stage IV to V occurred in four patients. In the light of these findings, an opthalmological examination may be considered as an important part of staging in feline lymphoma as well as of follow‐up examination in affected cats.     

Evaluation of Pax5 expression and comparison with BLA.36 and CD79αcy in feline non‐Hodgkin lymphoma

Paired box gene 5 (Pax5) is a widely used B‐cell marker for human and canine non‐Hodgkin's lymphoma (nHL); however, in the literature there is only one case report using Pax5 in a cat B‐cell lymphoma. The purposes of this study were to investigate the expression and detection of B‐cell specific activator protein (BSAP) using a monoclonal anti‐Pax5 antibody in feline nHL (FnHL) tissue samples to evaluate its diagnostic relevance as a B‐cell marker. A total of 45 FnHL samples in 45 cats were evaluated. B‐cell lymphoma was the most common immunophenotype (51.1%) for all the samples and T‐cell the most common immunophenotype (64.3%) for the gastrointestinal (GI) form. Pax5 stained 82.6% of all B‐cell lymphomas and no expression was found in any of the T‐cell lymphomas. Anti‐Pax5 antibody staining in FnHL is similar to that reported in human and canine counterparts and may offer an excellent B‐cell marker in cats.     

Histopathologic classification of 171 cases of canine and feline non-Hodgkin lymphoma according to the WHO

A retrospective collection of 171 lymphoid neoplasms (123 dogs and 48 cats) was classified according to the Revised European–American Lymphoma (REAL) classification, adopted in 2002 by the World Health Organization (WHO), to evaluate the WHO system for categorization of canine and feline neoplasms. Microscopic examination was performed after standard hematoxylin–eosin staining and immunohistochemical labelling for B (CD79a) or T (CD3) cell phenotypes. B-cell lymphomas were prevalent in dogs and T-cell lymphomas in cats. B-Large cell lymphoma (B-LCL) frequently showed plasmacytoid differentiation; notably, two canine plasma cell tumours (PCT) expressed both CD79 and CD3. There were difficulties in differentiating B-lymphoblastic lymphoma (B-LBL) from Burkitt-type lymphoma. Furthermore, intestinal T-cell lymphoma (ITCL) exhibited a huge morphologic variability. Finally, multicentric mature small and thymic T-cell lymphomas were diagnosed, although these categories are not codified by the WHO classification.     

Canine cutaneous epitheliotropic T‐cell lymphoma: a review of 30 cases

This retrospective study reviewed the clinical, histological and immunohistochemical features of 30 European cases of canine cutaneous epitheliotropic T‐cell lymphoma (CETL). The clinical presentation was highly variable and was not associated with the disease subtype. Diffuse erythema (86.6%) with scaling (60%) and focal hypopigmentation (50%) were the most common lesions. The skin was uniformly involved but muco‐cutaneous junctions or mucosae were affected in 50% of cases. The median age at diagnosis was 10 years (SD 2.79, range 4–15) and the median time between onset and final diagnosis was 5 months (SD 3.79, range 0–12). Five cases occurred in Bichon Frises. There was no evidence of a previous history of chronic dermatitis in any cases. Histologically, the follicular epithelium was affected in 86.7% of cases. One case with mainly follicular disease was considered folliculotropic mycosis fungoides (MF), but no follicular mucinosis was observed. Epidermal Pautrier’s microabscesses were uncommon (23.3%). Sweat glands were infiltrated in 70% of cases. Immunohistochemistry confirmed T‐cell neoplasia in all cases. B cells infiltrated as individual cells or formed linear bands or ectopic follicles at the base of the neoplasm. Ki67 labelling revealed a range of proliferation indices but did not correlate with severity. A final diagnosis of classical MF was made in 40% of the dogs, MF d’emblé in 36.7%, generalized Pagetoid reticulosis in 20% and localized Pagetoid reticulosis in one case (Woringer–Kolopp Pagetoid reticulosis). The median survival time after diagnosis was 6 months and this did not change appreciably with therapy (lomustine or prednisolone).     

Cytology and the cell block method in diagnostic characterization of canine lymphadenopathy and in the immunophenotyping of nodal lymphoma

Minimally invasive techniques used to evaluate canine peripheral lymphadenopathy (PLN), including fine needle aspiration biopsy with cytological evaluation (FNAB‐C) and flow cytometry (FC), have benefits and limitations. The cell block (CB) method is an alternate processing technique in which fine needle aspirate biopsy samples are concentrated, fixed, and embedded in paraffin for routine histological processing/staining. Utilizing three observers, we determined the diagnostic value of the CB in evaluating canine PLN across six categories (non‐diagnostic, reactive, inflammatory/infectious, probable lymphoma and lymphoma, metastatic neoplasia) and correlated findings to immunophenotypic and clonal antigen receptor rearrangement results in canine nodal lymphoma. Eighty‐five paired FNAB‐C and CB samples were evaluated from canine patients presenting to the University of Minnesota Veterinary Oncology or Internal Medicine services. Diagnostic quality samples were obtained in 55/85 (65%) CB and 81/85 (95%) FNAB‐C samples, respectively, and nodal pathology impacted CB diagnostic yield. Overall percent agreement between diagnostic‐quality FNAB‐C and CB samples was 86%, but increased to 95% if the categories of lymphoma and probable lymphoma were combined. There was 100% agreement for both the diagnoses of metastatic neoplasia and reactive lymph nodes and 92% agreement for the diagnosis of lymphoma/probable lymphoma. Using immunohistochemistry (IHC), CB samples correctly immunophenotyped 22/23 (96%) cases of B‐cell lymphoma, but only 1/6 (17%) cases of T‐cell lymphoma. IHC was not completed on nine cases of lymphoproliferative disease because of insufficient cellularity. When the CB method (CBM) yielded diagnostic quality samples there was good to excellent agreement with FNAB‐C samples and CB samples were suitable for some IHC tests.     

Aberrant phenotypes and quantitative antigen expression in different subtypes of canine lymphoma by flow cytometry

Flow cytometry may be a useful tool to analyze lymphoma samples that are obtained from fine needle aspirations (FNA). This study aimed to determine if flow cytometric analysis add more objective and standardized information on the cellularity and morphology of lymphoma cells to conventional cytology. The typical immunophenotype of different lymphoma subtypes was assessed and leukocyte marker expression was evaluated to determine which antigens were more frequently over- or under-expressed in these lymphoma subtypes. Fifty FNA lymph node samples were evaluated from canine lymphomas. Thirty-one samples were identified to be of B-cell origin, sixteen were identified to be of T/NK-cell origin and three cases were classified as acute lymphoblastic leukaemia with lymph nodes involvement. The most common B-cell lymphoma subtypes were centroblastic lymphomas, whereas three cases were atypical and classified as B-large cell pleomorphic lymphomas. Among the T/NK lymphomas, small clear cells, large and small pleomorphic mixed cells, large granular lymphocytic cells and small pleomorphic cells were identified. Aberrant phenotypes and/or antigen under/over regulation was identified in thirty out of forty-seven lymphoma cases (64%; 18/31 B-cell=58% and 12/16 T-cell=75%). In B-cell lymphomas the most frequent finding was the diminished expression of CD79a (45%). CD34 expression was also observed in four cases (13%). Among T-cell lymphomas the prevalent unusual phenotype was the under-expression or absence of CD45 (25%). These findings reveal flow cytometry may be useful in confirming the diagnosis of lymphoma, as the technique allows one to add useful information about morphology of the neoplastic cells and identify antigenic markers and aberrant phenotypes.     

Canine multicentric lymphoma 1: Clinico-pathological presentation of the disease

The clinicopathological features of 90 cases of canine multicentric lymphoma are described. The majority of cases occurred in middle-aged dogs (five to eight years of age) with a mean age at presentation of 6–7 years. A marked sex predisposition was noted with male dogs out numbering females by 2:1. No significant breed predispositions were found. The most common presentation was a generalised lymphadenopathy but in approximately one-third of the cases this was accompanied by other signs including polyuria and polydipsia, facial oedema and upper respiratory tract obstruction. Approximately two-thirds of all the cases showed non-specific haematological abnormalities including thrombocytopenia, anaemia and white blood cell anomalies. All the cases were clinically staged according to the anatomical extent of the disease. The majority of the dogs were classified as stage 3 or above, denoting that the disease is invariably widespread or systemic upon initial presentation.     

Comparison of chemotherapeutic drug resistance in cells transfected with canine ABCG2 or feline ABCG2

ABCG2 (ATP binding cassette subfamily G, member 2) mediates resistance to a variety of cytotoxic agents. Although human ABCG2 is well characterized, the function of canine ABCG2 has not been studied previously. Feline ABCG2 has an amino acid substitution in the adenosine triphosphate‐binding domain that decreases its transport capacity relative to human ABCG2. Our goal was to compare canine ABCG2‐mediated chemotherapeutic drug resistance to feline ABCG2‐mediated chemotherapeutic drug resistance. HEK‐293 cells stably transfected with plasmid containing canine ABCG2, feline ABCG2 or no ABCG2 were exposed to carboplatin, doxorubicin, mitoxantrone, toceranib or vincristine, and cell survival was subsequently determined. Canine ABCG2 conferred a greater degree of chemotherapy resistance than feline ABCG2 for mitoxantrone. Neither canine nor feline ABCG2 conferred resistance to doxorubicin, vincristine or toceranib. Canine, but not feline, ABCG2 conferred resistance to carboplatin, a drug that is not reported to be a substrate for ABCG2 in other species.     

Evaluation of a hematology analyzer with canine and feline blood

A semiautomatic electronic blood cell counter (Sysmex F-800:Toa Medical Electronics Europa Gmbh, Hamburg, Germany) was evaluated using canine and feline blood, following the International Committee for Standardization in Hematology protocol (ICSH, 1984). Precision and overall reproducibility were acceptable for all the parameters studied except for the feline platelet count, in which overlapping of erythrocyte and platelet populations prohibited determination of an accurate platelet count. Since carry-over from canine hematocrit values and platelet counts and from feline hematocrit values was unsatisfactory, the use of a blank diluent sample between different analyses was necessary. Linearity of the analyzer was acceptable in the studied range. Thirty canine and feline blood samples were analyzed using the Sysmex F-800 and a manual method. Correlations between both methods were acceptable for all the parameters, except for feline platelet count and erythrocyte indices for both species. In the storage study, red blood cell count and hemoglobin concentration were the parameters with the longest stability (72 hours at 4 degrees C and 25 degrees C) in both species. A statistically significant increase in MCV was obtained at 12 hours post-extraction in canine samples stored at 25 degrees C and at 24 hours in refrigerated samples. Feline leucocyte counts showed a downward trend at 12 hours post-extraction at both temperatures. Canine platelet count decreased significantly at 6 hours post-extraction in samples stored at 4 degrees C. During the evaluation period, Sysmex F-800 was user friendly and appeared well suited for routine canine and feline blood cell analysis.