Feline immunodeficiency virus status of Australian cats with lymphosarcoma

OBJECTIVE: To determine the FIV status of Australian cats with lymphosarcoma and relate this to patient characteristics, tumour characteristics (tissue involvement, histological grade and immunophenotype), haematological and serum biochemical values and FeLV status of affected cats. DESIGN: Prospective study of 101 client-owned cats with naturally-occurring lymphosarcoma. PROCEDURE: Western blot analysis, ELISA and immunochromatography were used to detect FIV antibodies in serum from cats with lymphosarcoma. RESULTS: On the basis of Western blot analysis (which was considered the most accurate method for determining FIV status), 50/101 (50%) of cats with naturally-occurring lymphosarcoma were positive for FIV antibodies. Of these 50 cats, 35 had tumours of B-cell phenotype, 13 had T-cell tumours and 2 had tumours classified as non-B/non-T. Tumours from eight of these FIV-positive cats contained FeLV gene sequences, including a 9-month-old cat with FeLV antigenaemia. Compared with FlV-negative cats with lymphosarcoma, FIV-positive cats were more likely to be domestic crossbreds (P = 0.004), male (P = 0.048) and have atypical (especially nasal) forms of lymphosarcoma (P = 0.09). Only 39 of 107 (36%) blood or sera tested using ELISA were positive for FIV antibodies (including 5 false-positives). CONCLUSIONS: The prevalence of FIV infection was considerably higher in our cohort of cats compared with series of lymphosarcoma cases from the Northern hemisphere. A positive FIV status was strongly associated with lymphosarcoma in Australian cats and it is possible that this infection may predispose to the development of lymphoid neoplasia. The presence of FIV infection would have been underestimated if commercial kits alone had been used for serology.     

Feline leukaemia virus status of Australian cats with lymphosarcoma

OBJECTIVE: To determine the FeLV status of sera and tumours from Australian cats with lymphosarcoma in relation to patient characteristics, tumour characteristics (tissue involvement, histological grade and immunophenotype), haematological and biochemical values. DESIGN: Prospective study of 107 client-owned cats with naturally-occurring lymphosarcoma. PROCEDURE: An ELISA was used to detect FeLV p27 antigen in serum specimens collected from cats with lymphosarcoma. A PCR was used to detect FeLV DNA in formalin-fixed, paraffin-embedded tissue sections containing neoplastic lymphoid cells. The PCR was designed to amplify a highly conserved region of the untranslated long terminal repeat of FeLV provirus. RESULTS: Only 2 of 107 cats (2%), for which serum samples were available, were FeLV-positive on the basis of detectable p27 antigen in serum. In contrast, 25 of 97 tumours (26%) contained FeLV DNA. Of the 86 cats for which both PCR and ELISA data were available, 19(22%) had FeLV provirus in their tumours but no detectable circulating FeLV antigen in serum, while 2 (2%) had FeLV provirus and circulating FeLV antigen. FeLV PCR-positive/ELISA-negative cats (19) differed from PCR-negative/ELISA-negative cats (65) in having fewer B-cell tumours (P = 0.06), more non B-/non T-cell tumours (P = 0.02) and comprising fewer non-Siamese/Oriental pure-bred cats (P = 0.03). CONCLUSIONS: The prevalence of FeLV antigen or provirus was considerably lower in our cohort of cats compared with studies of lymphosarcoma conducted in the Northern hemisphere. This suggests that factors other than FeLV are important in the development of lymphosarcoma in many Australian cats. No firm conclusions could be drawn concerning whether FeLV provirus contributed to the development of lymphosarcoma in PCR-positive/ELISA-negative cats.     

Characterisation of lymphosarcomas in Australian cats using polymerase chain reaction and immunohistochemical examination

Objective To examine tumour tissue of cats with lymphosarcoma for the presence of feline leukaemia virus and feline immunodeficiency virus and analyse the immunophenotype of the tumours.
Design A retrospective study of feline lymphosarcoma cases.
Methods Formalin-fixed, paraffin-embedded tumour tissue of 14 feline lymphosarcomas was examined for the presence of feline leukaemia virus and feline immunodeficiency virus by polymerase chain reaction and immunohistochemistry. Using polyclonal and monoclonal antibodies against T and B lymphocytes, the phenotypic expression of the tumours was characterised.
Results No feline leukaemia virus antigen or proviral sequences were detected. Feline immunodeficiency virus proviral sequences were detected in two cases by polymerase chain reaction. Immunophenotyping of all 14 cases resulted in seven cases being classified as B-cell phenotype, four as T-cell phenotype, and the remaining three undetermined.
Conclusions In contrast to previous reports overseas, our results suggest that feline leukaemia virus infection appears to be an infrequent cause of lymphosarcoma in the cats that were necropsied. Feline immunodeficiency virus may have a role in lymphomagenesis. The potential role of feline immunodeficiency virus needs to be explored in more depth. Compared with most previous reports, B-cell tumours were more common than T-cell tumours in this series of cats.     

Efficacy of doxorubicin as an induction agent for cats with lymphosarcoma

OBJECTIVE: To determine the efficacy of doxorubicin when used alone in inducing remission in cats with lymphosarcoma. DESIGN: Prospective multi-institutional study of naturally occurring disease. METHODS: Cases were accrued from veterinary institutions in Australia and New Zealand after obtaining consent from informed owners. Cats were treated with doxorubicin every 3 weeks for three treatments. If there was no response to the first dose of doxorubicin or if the cat relapsed during the doxorubicin regimen, the cat was withdrawn from the trial and either euthanased or treated with other agents. Age, breed, gender and anatomic site of the lymphosarcoma (multicentric, alimentary, mediastinal, extranodal) were recorded for each cat. Clinical remission was assessed before each treatment by physical examination, radiography, ultrasonography and computed tomography where appropriate. Complete remission was defined as the disappearance of all clinical signs and clinically detectable tumour. RESULTS: Twenty-one cases were accrued over a 2-year-period but only 19 were available for data analysis. Young Siamese cats were over-represented and all cats with mediastinal tumours were young Siamese. There was a significant difference between the mean ages of cats with mediastinal or multicentric lymphosarcoma (mean +/- SD: 3.5 +/- 3.0 and 4.3 +/- 2.6 years, respectively) and cats with alimentary or extranodal LSA (11.4 +/- 0.9 and 11.0 +/- 0.9 years, respectively). Of 19 cats treated with doxorubicin alone, 6 (32%) had complete remission, 6 (32%) had partial remission and 7 (36%) did not respond. CONCLUSIONS: The results suggest that doxorubicin cannot be recommended as a single agent for treatment of feline lymphosarcoma because of the rather poor remission rate achieved.     

Therapy for Australian cats with lymphosarcoma

OBJECTIVE: To determine the response of Australian cats with lymphosarcoma to chemotherapy and/or surgery in relation to patient and tumour characteristics, haematological and serum biochemical values and retroviral status. DESIGN: Prospective study of 61 client-owned cats with naturally-occurring lymphosarcoma subjected to multi-agent chemotherapy and/or surgery. PROCEDURE: An accepted chemotherapy protocol utilising l-asparaginase, vincristine, cyclophosphamide, doxorubicin, methotrexate and prednisolone was modified and used to treat 60 cats with lymphosarcoma. Clinical findings were recorded before and during therapy. As far as practical, cases were followed to death, euthanasia or apparent cure. Owner satisfaction with the results of chemotherapy was determined using a questionnaire sent after the completion of chemotherapy. RESULTS: One cat, with lymphosarcoma limited to a single mandibular lymph node, was treated using surgery alone and was cured. The other 60 cats were treated using multi-agent chemotherapy, although seven cats with localised intestinal, ocular and subcutaneous lesions had these lesions partially (2 intestinal lesions) or completely (2 eyes, 2 intestinal lesions and a cluster of regional lymph nodes) resected prior to starting chemotherapy. The median survival time for these 60 cats was 116 days. Of the 60 cats, 48 rapidly went into complete remission following the administration of 1-asparaginase, vincristine and prednisolone (complete remission rate 80%) and these cats had a median survival of 187 days. Three cats were censored from further analysis as their long-term survival data were uninterpretable because they died of causes unrelated to lymphosarcoma or were prematurely lost to follow-up. Twenty cats were classed as 'long-term survivors' based on survival time in excess of one year and at least 14 were 'cured' based on the absence of physical evidence of lymphosarcoma 2-years after initiating treatment. In other words, of the 48 cats that reached complete remission, in excess of 29% were 'cured'. Despite detailed analysis, few meaningful prognostic indicators based on patient or tumour characteristics were identified, although long-term survivors were more likely to be less than 4-years (P= 0.04) and to have tumours of the T-cell phenotype (P= 0.06). Excluding the one FeLV ELISA-positive cat with mediastinal LSA, 7 of 9 cats less than 4 years-of-age were long-term survivors (median survival time >1271 days). There was a strong association between achieving complete remission and long-term survival (P = 0.003). On the basis of 27 replies to a questionnaire, owners were generally very satisfied with the response to chemotherapy, irrespective of the survival time of the individual patient. Eighty five percent of owners expressed complete satisfaction with their decision to pursue chemotherapy and 70% believed their cat's health status improved during the first 2-weeks of treatment. Importantly, 78% of owners considered that chemotherapy required a very substantial time commitment on their part. CONCLUSIONS: It was possible to cure approximately one quarter of cats with lymphosarcoma using sequential multi-agent chemotherapy and/or surgery. FeLV-negative cats younger than 4 years (typically with mediastinal lymphosarcoma) had a particularly favourable prognosis. The decision to embark on chemotherapy should be based on the results of induction chemotherapy with l-asparaginase, vincristine and prednisolone, as the response to this was a good predictor of long-term survival. Cats surviving the first 16 weeks of chemotherapy generally enjoyed robust remissions (in excess of 1 year) or were cured of their malignancy.     

Clinical and anatomical features of lymphosarcoma in 118 cats

Objective To determine patients' characteristics and anatomical distribution of lesions in cats with lymphosarcoma. Design Prospective multi-institutional study of naturally occurring feline lymphosarcoma. Methods Veterinarians in Sydney were provided with free diagnostic laboratory services for suspect cases of feline lym-phosarcoma. Lymphosarcoma was diagnosed based on physical findings, radiographic and/or ultrasonographic images and results of cytological or histopathological examination. When owners were not interested in pursuing an antemortem diagnosis, suspect cases were collected for necropsy. Patients' characteristics and physical findings were recorded. A modified scheme for anatomical classification of lesions was devised including a ‘mixed’ category for cases which involved two or more anatomical forms. Results One hundred and eighteen cases were accrued over an 18 month period. The median age was 120 months and range 5 to 212 months. Age distribution was bimodal, with a small peak for cats less than 24 months, and a normal distribution centred on 97 to 120 months. Eighty cats were domestic crossbreds, 22 were Siamese or Oriental cats (including crosses), 6 were Burmese, 5 were purebred longhairs and the remaining 5 were one of a number of purebred shorthaired breeds. In comparison to 1017 consecutive cases admitted to our hospital for conditions other than lymphosarcoma, Siamese/Oriental cats were over-represented amongst lymphosarcoma cases (P = 0.0006). Male cats were also over-represented, accounting for 72 of 118 cases (P = 0.05). Abdominal lymphosarcoma was the most common anatomical form (43 cats), followed by mixed (39), nodal (20), mediastinal (9) and atypical (involving non-lymphoid organs, 7) forms. When analysed for specific organ involvement, 29 (25%) had mediastinal involvement, 71 (60%) had abdominal involvement including 60 (51%) with involvement of the intestinal tract and/or mesenteric lymph nodes and 36 (31%) with bilateral renal involvement, and 47 (40%) had peripheral lymph node involvement. No case of primary lymphoid leukaemia was identified. A noticeable subgroup of cats younger than 24 months had involvement of the anterior mediastinum with or without concurrent enlargement of cervical or axillary lymph nodes; Siamese/Oriental cats were over-represented in this subgroup. Among cases with nodal involvement, lymph nodes of the head and neck were frequently involved, mandibular nodes most commonly, followed by superficial cervical nodes. In seven cases a solitary node was affected. Conclusions Compared with similar surveys overseas, our cats were older and male cats were over-represented. There was a notable subgroup of young cats with mediastinal involvement. Siamese/Oriental cats were over-represented in this subgroup as well as in the larger population of cats with lymphosarcoma. Compared with overseas surveys, renal involvement, mixed cases and atypical cases (including nasal lymphosarcoma) were more common. A new subcategory of nodal lymphosarcoma, with involvement restricted to node(s) of head and neck, was identified.     

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.     

Primary and secondary bone tumours in the cat

Both primary and secondary bone tumours are rare in cats. Of the twenty-four cases of primary bone tumour, benign or malignant, in the cats of our study, the most common tumour was osteosarcoma (fifteen cats). The osteosarcomas tended to occur in aged female domestic short-hair cats; nine of the fifteen originated in the long bones of the extremities and three involved the skull. Four juxtacortical osteosarcomas, three chondro-sarcomas, and one example each of oesteoma and osteoid osteoma were found. The four juxtacortical osteosarcomas developed in relation to cranial bones, a location not recorded previously in cats.
Of the five tumour-like lesions of bone simulating primary tumours, three were aneurysmal bone cysts and two were fibrous dysplasias.
Of the twenty-nine cats with soft tissue tumours or tumour-like lesions involving bone, eleven had fibrosarcoma, eight had squamous cell carcinoma, three had lymphosarcoma, two had rhabdomyosarcoma, and one example of each was malignant melanoma, haemangiosarcoma, reticulum-cell sarcoma, meningioma and myositis ossificans.
Osteoid osteoma, fibrous dysplasia and myositis ossificans were not previously recorded in the cat.     

Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection

OBJECTIVES: To determine the efficacy of ronidazole (RDZ), tinidazole (TDZ), and metronidazole (MDZ) against Tritrichomonas foetus in vitro and of RDZ for treatment of feline naturally occurring or experimentally induced T. foetus infection. ANIMALS: A cat naturally infected with T. foetus infection and diarrhea. Ten specific-pathogen-free (SPF) kittens. PROCEDURE: RDZ, TDZ, and MDZ were tested for activity against 3 different feline isolates of T. foetus in vitro. RDZ then was administered to a naturally infected cat at 10 mg/kg PO q24h for 10 days. SPF kittens were infected orogastrically with feline T. foetus and treated with either placebo or RDZ (10 mg/kg PO q12h for 14 days). Cats with relapsing infection or those receiving placebo were treated subsequently with RDZ (either 30 or 50 mg/kg PO q12h for 14 days). Feces were examined for T. foetus by direct microscopy, culture, and polymerase chain reaction (PCR) testing weekly. RESULTS: Both RDZ and TDZ killed T. foetus at concentrations >0.1 microg/mL in vitro. In the naturally infected cat, RDZ abolished diarrhea and T. foetus infection for 85 days after treatment, at which time infection and diarrhea relapsed. Retreatment with RDZ eradicated diarrhea and T. foetus infection for over 407 days. In experimentally induced infection, RDZ at 10 mg/kg caused initial improvement, but infection relapsed in all 5 cats 2 to 20 weeks after treatment. At 30 or 50 mg/kg, 10/10 cats were negative for T. foetus infection for follow-up durations of 21 to 30 weeks after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of RDZ at 30 to 50 mg/kg q12h for 14 days resolved diarrhea and eradicated infection (on the basis of polymerase chain reaction [PCR] testing) in 1 naturally infected cat and 10 experimentally inoculated cats receiving a different isolate of T. foetus.     

Titres of alloantibodies against A and B blood types in non-pedigree domestic cats in Turkey: assessing the transfusion reaction risk

The severity of a transfusion reaction depends on alloantibody titres within the recipients' blood. Determination of an agglutination titre of naturally occurring alloantibody may help to assess the risk of transfusion reactions following an unmatched transfusion in a cat population. In this group of 312 cats 227 had blood type A, 78 had blood type B, and seven had type AB blood. All type B cats tested showed gross evidence of agglutinating anti-A antibody with plasma titres ranging from 2 to 256. Among the 227 type A domestic cats tested for plasma anti-B alloantibody titres, 70% had gross agglutination with titres ranging from 2 to 16, while 17.6% had microscopic agglutination. The remaining 12.4% of the type A cats were negative for both gross and microscopic agglutination. Based on agglutinating titres, the relative risk of a transfusion reaction when type A or AB blood was given to a type B cat was 6.4% with acute severe reaction, acute mild reactions in 85.9% and premature red cell destruction in 7.7%. On the other hand, transfusion of type AB blood or type B blood to type A cats carries a potential risk of acute mild transfusion reaction in 4.4% and premature red cell destruction in 83.3%. Transfusion of type A or B blood to type AB cats results in no apparent clinical transfusion reactions.     

Haematological and biochemical findings in cats in Australia with lymphosarcoma

OBJECTIVE: To describe, for the first time, haematological and serum biochemical findings in cases of lymphosarcoma in Australian cats. DESIGN: A prospective multi-institutional study. PROCEDURE: Of 118 affected cats presented to the authors over a 18-month period, 97 were evaluated haematologically and 87 biochemically. Haematological analysis usually included determination of packed cell volume, haemoglobin concentration, red blood cell and leukocyte counts, differential leukcocyte count, reticulocyte count and examination of buffycoat smears for neoplastic cells. Serum biochemical analysis was done primarily with a discrete analyser and included a panel of commonly used analytes. RESULTS: Nonregenerative anaemia was present in 54% (52/97) of cats. Neutrophilia, present in 65% (59/91) of cats, was commonly associated with lymphocytopaenia, eosinopaenia and monocytosis. Of the 13 cats with a secondary leukaemic manifestation, only five had distinct lymphocytosis. Serum biochemical abnormalities either were nonspecific, such as hypoglycaemia in 37% (32/87) of cats, or related to specific tissue involvement, such as hypoalbuminaemia in 76% (31/41) of cats with alimentary involvement and azotaemia in 60% (15/25) of cats with renal involvement. CONCLUSION: It was shown for the first time that haematological and serum biochemical findings are of limited value in diagnosing lymphosarcoma in Australian cats, except if they are leukaemic. Although clinical pathological changes were common, they were nonspecific or related to specific tissue involvement. Their value in assessing response to therapy needs to be examined further. Patient characteristics such as age, breed and sex also had limited effect on laboratory findings and those observed were of little consequence. Additionally, histological and immunophenotypical variations in tumour type had little effect on laboratory findings.     

Treatment of feline diabetes mellitus using an alpha-glucosidase inhibitor and a low-carbohydrate diet

The purpose of this study was to determine the effect of an alpha-glucosidase inhibitor (acarbose), combined with a low-carbohydrate diet on the treatment of naturally occurring diabetes mellitus in cats. Eighteen client-owned cats with naturally occurring diabetes mellitus were entered into the study. Dual-energy X-ray absorptiometry (DEXA) was performed prior to and 4 months after feeding the diet to determine total body composition, including lean body mass (LBM) and percent body fat. Each cat was fed a commercially available low-carbohydrate canned feline diet and received 12.5mg/cat acarbose orally every 12h with meals. All cats received subcutaneous insulin therapy except one cat in the study group that received glipizide (5mg BID PO). Monthly serum glucose and fructosamine concentrations were obtained, and were used to adjust insulin doses based on individual cat's requirements. Patients were later classified as responders (insulin was discontinued, n=11) and non-responders (continued to require insulin or glipizide, n=7). Responders were initially obese (>28% body fat) and non-responders had significantly less body fat than responders (<28% body fat). Serum fructosamine and glucose concentrations decreased significantly in both responder and non-responder groups over the course of 4 months of therapy. Better results were observed in responder cats, for which exogenous insulin therapy was discontinued, glycemic parameters improved, and body fat decreased. In non-responders, median insulin requirements decreased and glycemic parameters improved significantly, despite continued insulin dependence. The use of a low-carbohydrate diet with acarbose was an effective means of decreasing exogenous insulin dependence and improving glycemic control in a series of client-owned cats with naturally occurring diabetes mellitus.     

Hypereosinophilic paraneoplastic syndrome in a cat with intestinal T cell lymphosarcoma

A 10-year-old, neutered female, domestic shorthair cat was presented with a recent history of weight loss, polydipsia, diarrhoea and vomiting. On physical examination, intestinal thickening and mesenteric lymph node enlargement were apparent. Clinical investigations revealed peripheral blood eosinophilia, eosinophilic abdominal effusion and eosinophilic mesenteric lymphadenitis. There was a temporary response to treatment with glucocorticoids but signs progressed and the cat was euthanased. On histology, there was eosinophilic infiltration and fibroplasia of intestine and mesenteric lymph nodes. Large aggregates of neoplastic round cells in the intestine and lymph nodes were identified as T lymphocytes using immunohistochemistry. A diagnosis of intestinal T cell lymphosarcoma was made. This case demonstrates that hypereosinophilic paraneoplastic syndrome may occur in cats with lymphosarcoma. Eosinophil chemotaxis may be a response to the production of interleukin-5 by neoplastic lymphocytes.     

Intracranial neoplasia in 61 cats: localisation, tumour types and seizure patterns

The purpose of this study was to analyse retrospectively a feline population with intracranial neoplastic diseases, to document seizure patterns in these animals and to determine whether partial seizures were more frequently associated with structural brain lesions then generalised seizures. In addition, a comparison was made within the population with intracranial neoplasia between two groups of cats: one with and one without seizures. Special emphasis was given to the evaluation of tumour type, localisation and size of the lesion and its correlation with seizure prevalence. Sixty-one cats with histopathological diagnosis of intracranial tumour were identified. Fourteen cats (23%; group A) had a history of seizure(s). Forty-seven cats (77%; group B) had no history of seizure(s). Generalised tonic-clonic seizures were seen in eight cats (57%) and were the most common seizure pattern in our cats with intracranial neoplasia. Clusters of seizures were observed in six cats. Status epilepticus was observed in one patient. The mean age of the cats was 7.9 years within group A (median 8.5) and 9.3 years (median 10) within group B. The cats with lymphoma within both groups were significantly younger than cats with meningioma. In both groups meningioma and lymphoma were confirmed to be the most frequent tumour type, followed by glial cell tumours. The prevalence of the seizures in patients with glial cell tumours was 26.7%, 26.3% in patients with lymphomas and 15% in cases with meningiomas. In 33 cases (54.1%) the tumours were localised in the forebrain, 15 tumours (24.6%) were in the brainstem, four (6.6%) in the cerebellum and nine tumours (14.7%) had multifocal localisation. Parietal lobe and basal ganglia mostly affected group A. In group B tumours were most frequently located in the parietal and frontal lobes as well as in the diencephalon. A positive association was documented between the localisation of a tumour in the forebrain and seizure occurrence.     

Trichosporonosis in two cats

Infection with Trichosporon spp was diagnosed in 2 cats. In one cat, infection consisted of a granulomatous dermatitis and was concurrent with disseminated lymphoblastic lymphosarcoma. In another cat, urinary cystitis caused by T beigelii was diagnosed.     

Lymphosarcoma and cryptococcosis in a cat

Cryptococcosis and lymphosarcoma were diagnosed in a 3-year-old Domestic Shorthair cat. The cat was studied immunologically, and abnormal findings included absolute lymphopenia, with a low percentage of the lymphocytes having cell surface markers of normal T and B cells, decreased responsiveness to mitogens, and low immunoglobulin concentrations in serum. Necropsy revealed cryptococcal lesions in the facial area. The cortex of the left kidney was replaced by a diffuse pattern of undifferentiated large cells compatible with those of histiocytic cell type lymphosarcoma.     

Tolerability of Gemcitabine and Carboplatin Doublet Therapy in Cats with Carcinomas

Background: This study was performed to determine the toxicity of gemcitabine-carboplatin doublet therapy in cats with carcinomas.
Hypothesis: Gemcitabine and carboplatin are safe in tumor-bearing cats.
Animals: Twenty cats with spontaneously occurring carcinomas.
Methods: A cohort of 6 cats received gemcitabine (2 mg/kg IV) on days 1, 8, and 15 and carboplatin (10 mg/kg IV) immediately after gemcitabine on day 1 of a 21-day cycle. A 2nd cohort of 14 cats received carboplatin 4 hours after gemcitabine on day 1 and gemcitabine on day 8 but not day 15. The cycles were repeated every 21 days.
Results: Cats in the 1st cohort received a median of 3.75 cycles per animal (range, 1–6). Two cats (33.3%) developed grade 3 or 4 neutropenia, 1 (16.7%) grade 4 thrombocytopenia, and 1 (16.7%) grade 3 gastrointestinal toxicity. Gemcitabine dose reductions and treatment delays occurred in 1 and 4 cats, respectively. Cats in the 2nd cohort received a median of 2 cycles per animal (range, 0.5–10). Two cats (14.3%) had grade 3 or 4 neutropenia and 1 (7.1%) had grade 3 and 4 gastrointestinal toxicity. One cat required gemcitabine dose reduction and 6 had treatment delays. In the 2nd cohort, of 11 cats with measurable tumors, there was 1 complete response (pancreatic carcinoma) and 1 partial response (squamous cell carcinoma, receiving concurrent nonsteroidal anti-inflammatory drugs).
Conclusions and Clinical Importance: Gemcitabine-carboplatin combination appears moderately well tolerated in tumor-bearing cats. Minimal patient benefit suggests that alternative schedules or combinations of gemcitabine with other agents should be explored.     

GS-441524对自然感染的猫传染性腹膜炎的治疗效果观察

试验旨在观察GS-441524对自然感染的猫传染性腹膜炎（FIP）病例的临床疗效，为临床用药提供参考。试验招募了25只于中国农业大学动物医院确诊为FIP的患猫，随机分为高剂量组（5 mg/（kg·d））（12只）和低剂量组（2.5 mg/（kg·d））（13只），每日皮下注射GS-441524治疗并记录体重、体温、注射药物的疼痛反应及每周的实验室及影像学检查结果以评价药物疗效。设定治疗周期为4周，部分病例根据实际情况延长治疗时间。结果显示，共计20只湿性FIP和3只干性FIP患猫完成试验，2只患猫退出。治疗时间为4~18周。20只湿性FIP患猫中，2只在1周内死亡，1只体腔积液增加，17只用药1周后积液减少，用药2~3周后积液消失。3只干性FIP患猫中，2只患猫的肠系膜淋巴结在用药1~2周后减小，1只无明显变化。所有患猫的精神和食欲在用药3~5 d内改善；体重在1~2周内开始增长；5只发烧的患猫用药2~3 d后体温恢复正常；14只贫血的患猫用药1~10周后恢复正常；16只患猫出现白细胞数量升高且淋巴细胞数量下降或中性粒细胞数量升高，用药1~2周内开始好转。所有患猫血清中白蛋白和球蛋白的比值（白球比）均<0.8，其中9只总蛋白升高，4只白蛋白降低，14只球蛋白升高，用药1~2周后开始好转。高剂量组的患猫4周药物有效率和治愈率分别为81.8%和60.0%，低剂量组的患猫4周药物有效率和治愈率分别为75.0%和22.2%。用药4周前后，高剂量组的患猫除白细胞总数（WBC）和白蛋白（ALB）外，其余指标均差异显著或极显著（P<0.05；P<0.01）；而低剂量组的患猫仅体重差异显著。除血红蛋白（HGB）、WBC和ALB外，药物对患猫的体重、红细胞（RBC）、红细胞压积（HCT）、淋巴细胞（LYM）、中性粒细胞（NEU）、总蛋白（TP）、球蛋白（GLOB）及白球比（A/G）改善情况差异显著（P<0.05），且高剂量药物效果更佳。综上，GS-441524能有效治疗自然感染的FIP，高剂量（5 mg/（kg·d））疗效更佳，最短治疗周期为4周。     

Selective impairment of humoral immunity in feline leukemia virus-induced immunodeficiency.

We used a panel of in vitro assays to investigate the nature of immune dysfunction in cats infected with FeLV-FAIDS, a naturally occurring, molecularly cloned feline leukemia virus (FeLV) isolate which induces a fatal immunodeficiency syndrome in infected cats. During the asymptomatic period preceding immunodeficiency disease, we were unable to detect any deficits in concanavalin A-induced blastogenesis, xenogeneic mixed-lymphocyte reaction assays, stimulation of lymphocytes by soluble protein antigen, and cytotoxic T lymphocyte assays. However, during this period humoral immune responses in the FeLV-FAIDS-infected cats were dramatically impaired. As early as 9 weeks after virus inoculation, the ability to mount either an IgM or IgG response to soluble protein antigens was lost. Neither B cell function, as assessed by lipopolysaccharide-induced blastogenesis or circulating B cell numbers, as assessed by immunofluorescence, differed between infected and control cats. These results suggest that FeLV-FAIDS infection may impair a subpopulation of T helper cells, that provides help for the production of antibody. Consistent with earlier observations of cats naturally infected with FeLV, our results indicate that early impairment of humoral immunity is an important component of the immunodeficiency syndrome induced by FeLV in cats.     

Cytauxzoonosis in domestic cats: report of two cases in Oklahoma, with a review and discussion of the disease

In 2 cases of cytauxzoonosis in domestic cats in Oklahoma, the clinical features, gross lesions, and microscopic findings were of similar nature and degree to those previously reported by others, both in the naturally occurring and experimentally induced disease. Intraerythrocytic forms of Cytauxzoon felis organisms were demonstrated in stained blood smears from one cat. Blood from the other cat was not examined. The diagnosis was established by the finding of schizonts in endothelial-associated macrophages within vascular channels in tissues from both cats.