Evaluation of a multidrug chemotherapy protocol with mitoxantrone based maintenance (CHOP-MA) for the treatment of canine lymphoma.

The purpose of this study was to evaluate the efficacy of adding mitoxantrone to a cyclophosphamide, doxorubicin, vincristine, L-asparaginase and prednisone containing protocol. Sixty-five dogs with multicentric lymphoma were evaluated for overall remission and survival times. Remission and survival time versus stage, substage, pretreatment hypercalcaemia and pretreatment steroid administration were also evaluated. Overall median remission for dogs with multicentric lymphoma was 302 days and overall median survival was 622 days. Of the dogs with multicentric lymphoma, 23 (35%) received all scheduled mitoxantrone doses. Only median survival versus substage was found to be significant (substage a median survival was 679 days and substage b median survival was 302 days, P = 0.025). Increasing the total combined dose of doxorubicin and mitoxantrone may improve remission times when compared with historical controls, and further studies are needed to determine how best to utilize mitoxantrone in multidrug chemotherapy protocols for canine multicentric lymphoma.

Radiosensitivity of canine osteosarcoma cells transfected with wild-type p53 in vitro.

The p53 gene is one of the important tumour suppressor genes that are involved with the cell survival signal pathway. One of the major functions of the p53 protein is to organize cell cycle regulation and induction of apoptosis for cellular genetic stability. It has been documented that more than 50% of all human cancers include a p53 mutation. We evaluated the difference in radiosensitivity between upregulating the expression of canine wild-type p53 (cp53) in cultured osteosarcoma (D17) cells and naive D17 cells in vitro. We found that upregulating transfected cp53 D17 cells increased their radiation sensitivity in vitro, and there was a significant decrease (P < 0.009) in survival between cp53-transfected D17 cells and naive D17 cells. In this experiment, a p53 enhancement ratio (p53ER) reached approximately 3.0 at high doses. The transfected cp53 D17 cells were significantly more radiosensitive at all doses evaluated than naive D17 cells, except at 1 Gy where too few data points were available. The p53ER increased rapidly at doses less than 4 Gy, achieving a maximum of about 3.0 for doses of 4 Gy and above. This study shows the enhanced radiosensitivity of the transfected p53 at clinically relevant doses.

Evaluation of plasma folate and homocysteine concentrations in cats with and without oral squamous cell carcinoma.

Feline oral squamous cell carcinoma (SCC) is a devastating disease with an extremely poor long-term prognosis even with aggressive therapy. Folate and homocysteine derangements are identified in people diagnosed with head and neck SCC. The purpose of this study was to measure plasma folate and homocysteine concentrations in cats diagnosed with oral SCC (n = 13) and to compare these concentrations with those found in cats diagnosed with other tumour types (n = 25), cats with oral, non-neoplastic disease (n = 6) and healthy cats (n = 24). The median plasma folate concentration in cats diagnosed with oral SCC was 14.7 ng mL(-1), while the median plasma homocysteine concentration was 2.61 microg mL(-1). These concentrations did not differ significantly from those of cats in the other groups. This suggests that different factors may contribute to the pathogenesis of this tumour in cats when compared with people, although evaluation of larger numbers of cats may still identify a difference between groups.

Efficacy and toxicity of BOPP and LOPP chemotherapy for the treatment of relapsed canine lymphoma.

Mechlorethamine (Mustargen), Oncovin) (vincristine), procarbazine and prednisone (MOPP) chemotherapy is useful for relapsed canine lymphoma. This study evaluates the efficacy of MOPP after substitution of CCNU (lomustine, LOPP protocol) or BCNU (carmustine, BOPP protocol) for mechlorethamine in 60 dogs with relapsed lymphoma. Seven of 14 (50%) dogs treated with BOPP responded, for a median of 129.5 days for complete responders (range 9-354 days) and a median of 140 days for partial responders (range 4-276 days). Twenty-three of 44 (52%) dogs treated with LOPP responded for a median of 112 days for complete responders (range 48-250 days) and a median of 84.5 days for partial responders (range 69-290 days). Two dogs receiving a combination of LOPP and BOPP partially responded for 28 and 163 days, respectively. With BOPP chemotherapy, nine dogs (20.5%) and seven dogs (50%) had one or more episodes of Grade II or higher neutropenia and thrombocytopenia, respectively. Seven dogs (50%) had one or more episodes of Grade II or higher gastrointestinal toxicity. While receiving LOPP chemotherapy, 28 dogs (63.6%) and 17 dogs (38.6%) had one or more episodes of Grade II or higher neutropenia and thrombocytopenia, respectively. Seventeen dogs (38.6%) had one or more episodes of Grade II or higher gastrointestinal toxicity. Overall, there were 17 non-fatal treatment-related episodes of sepsis requiring hospitalization. Eight dogs (13%) died or were euthanized because of treatment-related sepsis and/or chemotherapy-related complications. Severe haematologic toxicity, coupled with the improved response duration observed in dogs receiving reduced doses during B/L-OPP rescue, underscores the need for protocol optimization.

Telomerase activity and related properties of normal canine lymph node and canine lymphoma.

Telomerase activity (TA) and the expression of p16(INK4), telomerase reverse-transcriptase catalytic subunit (TERT) and proliferating cell nuclear antigen (PCNA) were analysed in lymph nodes from clinically normal dogs and from dogs with lymphoma. Telomere lengths were measured in 12 histologically normal lymph nodes. These data were related to the overall survival time of the lymphoma patients given chemotherapy, in an effort to identify prognostic significance of the measured variables. There was no significant difference between TA of normal lymph nodes (n = 16) and lymphoma lymph nodes (n = 6). PCNA expression was significantly higher in lymphoma (n = 30) than in normal lymph nodes (n = 10), but TERT expression was not. Expression of p16(INK4) was not significantly different between normal and lymphoma lymph nodes. TA and p16(INK4) expression were inversely correlated within the normal lymph nodes studied. Telomere lengths in normal lymph nodes were consistent with previous studies. No variables examined had any correlation with survival of the lymphoma patients given chemotherapy. The role of p16(INK4) in the regulation of TA warrants further investigation.

Cloning, expression and in vitro evaluation of recombinant canine Tum5, an angiostatic domain of mammalian type IV collagen.

The process of new blood vessel formation within and around neoplastic tissue, termed angiogenesis, is a significant factor in the development, progression and metastasis of malignant tumours in all species. A major cause of death in cancer patients is the development of treatment-resistant metastatic disease, which may be avoided by therapies that target the genetically stable population of vascular endothelial cells within tumours. Tumstatin is a small protein formed by the cleavage of the alpha-3 subunit of the non-collagenous domain of mammalian type IV collagen. Recombinant human Tumstatin has been shown to have potent angiostatic properties in vitro and in vivo. Tumstatin is a potent initiator of apoptosis and inhibits the proliferation and migration of vascular endothelial cells in cell culture. Recently, a fragment of Tumstatin, termed Tum5, has been shown to have biologic activity similar to the parent compound. The systemic administration of angiostatic proteins like Tum5 may result in the remission of established tumours, while preventing or delaying the onset of clinically detectable metastasis. Recombinant canine Tum5 (cTum5) was cloned and its protein expression induced in a prokaryotic vector. The resulting cTum5 protein caused dose-dependent inhibition of vascular endothelial cells in vitro, which appears to be mediated through apoptosis.

Nitrogen balance in clinically normal dogs receiving parenteral nutrition solutions.

OBJECTIVE: To determine nitrogen balance in clinically normal dogs receiving parenteral nutrition solutions. ANIMALS: 8 clinically normal female Beagles. PROCEDURE: Dogs were randomly assigned to receive 4 treatments in random order. Treatment A consisted of IV administration of nonlactated Ringer's solution. Treatments B, C, and D consisted of IV administration of isocaloric parenteral solutions containing 0, 1.36, and 2.04 g of amino acids/kg of body weight/d, respectively, for 7 consecutive days. Urine and feces were collected on days 5, 6, and 7 of each treatment period, and Kjeldahl analysis was used to determine nitrogen balance. RESULTS: Mean nitrogen balance was negative with treatments A and B but was not significantly different from 0 with treatments C and D. Dogs had the lowest nitrogen balance values and lost the most weight while receiving treatment A. Dogs were able to conserve protein and had higher nitrogen balance values when receiving treatment B, compared with treatment A. Dogs lost the least amount of weight while receiving treatment D. Regression analysis indicated that an IV amino acid intake of 2.32 g/kg/d (95% confidence interval, 2.00 to 2.81 g/kg/d), as supplied by the commercial product used in this study, would result in zero nitrogen balance in clinically normal dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that IV amino acid requirement of clinically normal dogs is approximately 2.3 g/kg/d.

Serum alpha 1-acid glycoprotein concentration in cats with lymphoma.

Serum alpha 1-acid glycoprotein (AGP) concentrations were evaluated in nine cats with lymphoma. Twenty-five healthy cats were used as controls. Blood samples were obtained from cats with lymphoma prior to induction chemotherapy, one week following induction, at complete response, and at monthly intervals. The median pretreatment AGP concentration for the nine cats with lymphoma was significantly higher than the median AGP concentration for the 25 control cats. Remission serum AGP concentration was not significantly different from the pretreatment AGP concentration in the cats with lymphoma. Serum AGP concentrations provided no useful information regarding response or survival in cats with lymphoma.

Results of irradiation of infiltrative lipoma in 13 dogs.

Thirteen dogs with infiltrative lipomas were treated with cobalt 60 radiation. Four of the thirteen dogs also received either whole body (n = 2) or combination local/whole body (n = 2) hyperthermia in conjunction with radiation therapy. Cytoreductive surgery was performed prior to radiation in 10 dogs, although only 3 dogs had microscopic disease at the time of radiation therapy. Dogs received a total dose of 45.6 Gy-63 Gy in 2.5-4 Gy/fraction on either a Monday/Wednesday/Friday schedule or on a daily Monday through Friday schedule. Twelve of the 13 dogs had computed tomography (CT) images acquired prior to irradiation. Survival time was determined from the time of completion of radiation therapy. Survival ranged from 6 months to 94 months, with a median (95% confidence interval) of 40 (18.5-77) months and a mean of 46.4 months. Only one dog was euthanized due to persistent signs related to the infiltrative lipoma at 6 months after the end of radiation therapy. There was no apparent difference in response based on whether or not the dogs received hyperthermia in conjunction with irradiation, although the numbers were too small to make any significant conclusions. It appears that dogs with infiltrative lipomas can benefit from external beam irradiation alone or in combination with surgery to effect long-term local tumor control.

Prognostic factors in dogs with urinary bladder carcinoma.

Medical records and biopsy specimens were retrospectively reviewed from 25 dogs diagnosed with unresectable urinary bladder carcinoma and treated with chemotherapy. Our intention was to identify clinical, histologic, and immunohistochemical indicators of prognosis. Immunohistochemical stains for P-glycoprotein, glutathione-S-transferase pi, and factor VIII-related antigen were applied to archived tissue. There were more spayed female dogs than castrated male dogs (76% versus 24%). Transitional cell carcinoma was the most common tumor (88%, n = 22), followed by undifferentiated carcinoma (8%, n = 2) and squamous cell carcinoma (4%, n = 1). Overall median survival was 251 days. Histologic diagnosis and immunohistochemical characteristics did not correlate with prognosis. Spayed females survived significantly longer than castrated males (358 days versus 145 days, P = .042). Dogs that received either doxorubicin or mitoxantrone in addition to a platinum-based chemotherapeutic (either cisplatin or carboplatin) lived significantly longer than those that received only a platinum compound (358 days versus 132 days, P = .042).

Radiation treatment for incompletely resected soft-tissue sarcomas in dogs.

OBJECTIVE: To evaluate efficacy of radiation for treatment of incompletely resected soft-tissue sarcomas in dogs. DESIGN: Prospective serial study. ANIMALS: 48 dogs with soft-tissue sarcomas. PROCEDURE: Tumors were resected to < 3 cm3 prior to radiation. Tumors were treated on alternate days (three 3-Gy fractions/wk) until 21 fractions had been administered. Cobalt 60 radiation was used for all treatments. RESULTS: Five-year survival rate was 76%, and survival rate was not different among tumor types or locations. Four (8%) dogs developed metastases. Eight (17%) dogs had tumor recurrence after radiation. Development of metastases and local recurrence were significantly associated with reduced survival rate. Median survival time in dogs that developed metastases was 250 days. Median disease-free interval for all dogs was 1,082 days. Median time to recurrence was 700 days. Dogs that developed recurrence after a prolonged period responded well to a second surgery. Acute radiation toxicosis was minimal; osteosarcoma developed at the radiation site in 1 dog. CONCLUSIONS AND CLINICAL RELEVANCE: An excellent long-term survival rate may be achieved by treating soft-tissue sarcomas in dogs with resection followed by radiation. Amputation is not necessary for long-term control of soft-tissue sarcomas in limbs. Development of metastases and recurrence of local tumors after radiation treatment are associated with decreased survival rate. Acute and delayed radiation toxicosis was minimal with the protocol used in this study.

Metabolic and hormonal alterations in cats with hepatic lipidosis.

Hepatic lipidosis in cats is a commonly diagnosed hepatobiliary disease of unknown cause. The purpose of this prospective study was to characterize the blood hormone and lipid status of cats with hepatic lipidosis, and to compare this status to that of cats with other types of liver disease and to control cats. Twenty-three cats with hepatic disease were assigned to 1 of 2 groups on the basis of cytopathologic or histopathologic examination of the liver: group 1, hepatic lipidosis (n = 18); or group 2, cholangiohepatitis (n = 5). Ten healthy young adult cats were used as controls. Food was withheld from control animals for 24 hours before blood collection. Concentrations of plasma glucagon and serum insulin, cortisol, thyroxine, triglycerides, cholesterol, phospholipids, and nonesterified fatty acids (NEFAs) were determined in all cats, in addition to routine hematologic and serum biochemical testing. Cats with hepatic lipidosis had higher serum NEFA concentrations than cats with cholangiohepatitis or control cats (P < .05). Cats with cholangiohepatitis had higher serum cholesterol and phospholipid concentrations than those of cats with lipidosis or control cats (P < .05); their plasma glucagon concentrations were higher than those of control cats (P < .05), but were not different from those of cats with hepatic lipidosis. Serum insulin concentrations were significantly higher in control cats than in diseased cats (P < .05), but neither serum insulin nor the insulin to glucagon ratio was significantly different among the cats with hepatic disease. The high concentration of NEFAs in cats with hepatic lipidosis suggests that at least 1 factor in the pathogenesis of this syndrome may involve the regulation of hormone-sensitive lipase.

Prognostic value of argyrophilic nucleolar organizer region (AgNOR) staining in feline intestinal lymphoma.

Limited information is available on prognostic factors for cats with lymphoma. The quantity of argyrophilic nucleolar organizer region (AgNOR) proteins can be used as a measurement of cellular proliferative activity. To determine if AgNORs were of prognostic value for feline intestinal lymphoma, the silver staining technique was performed on paraffin-embedded sections of 31 cases. Mean number of AgNORs per nucleus ranged from 1.02 to 4.32. Twenty-four (78%) cats had small AgNORs and 7 (22%) had large AgNORs. All cats were treated identically with a combination chemotherapy protocol. Response to chemotherapy was 87%. Median remission duration and survival times were 120 days and 201 days, respectively. No significant correlation was found between mean number of AgNORs per nucleus or AgNOR size and remission rate, remission duration, or survival time. This study indicates that AgNOR staining is not a useful prognostic factor for cats with intestinal lymphoma.

Clinicopathologic features of dogs with hepatic microvascular dysplasia with and without portosystemic shunts: 42 cases (1991-1996).

OBJECTIVE: To identify and compare clinicopathologic features between dogs with hepatic microvascular dysplasia (HMD) and confirmed portosystemic shunts (PSS) and dogs with HMD alone and to determine whether any discriminating variables can be identified to differentiate the conditions. DESIGN: Retrospective study. ANIMALS: 42 dogs with HMD. PROCEDURE: Medical records of dogs with HMD examined between January 1991 and October 1996 at 3 veterinary hospitals were reviewed. RESULTS: Compared with dogs with PSS and HMD, dogs with HMD alone were older and had higher values for mean corpuscular volume (MCV) and serum total protein, albumin, creatinine, cholesterol, BUN, and blood glucose concentrations. Compared with dogs with HMD alone, dogs with PSS and HMD had higher values for pre- and postprandial serum bile acid concentrations, WBC, and serum alkaline phosphatase and aspartate aminotransferase activities. The most discriminating variables for the 2 conditions were serum postprandial bile acid concentrations, MCV, and serum albumin and cholesterol concentrations. CLINICAL IMPLICATIONS: The discriminant variables of postprandial serum bile acid concentrations, MCV, and serum albumin and cholesterol concentrations may be useful in distinguishing between dogs with HMD alone and dogs with PSS and HMD.

Malignant colonic neoplasia in cats: 46 cases (1990-1996).

OBJECTIVE: To evaluate a group of cats with malignant colonic neoplasia and to identify factors related to survival time. DESIGN: Retrospective study. ANIMALS: 46 cats with malignant colonic neoplasia. PROCEDURE: Information on signalment, diagnostic findings, histopathologic diagnosis, surgical procedure performed, identification of nodal metastasis at surgery, type of chemotherapy administered, and survival time was obtained from the medical record of each cat. A diagnosis of malignant colonic neoplasia had been established by histologic examination of endoscopic biopsy specimens (3 cats), biopsy specimens obtained during laparotomy (38), or necropsy specimens (5). RESULTS: Mean age of cats was 12.5 years (range, 6 to 18 years). Ultrasonography was useful 84% of the time in localizing the mass to the intestine. Three cats had endoscopic biopsy, 9 had incisional biopsy, 21 had mass resection, and 8 had subtotal colectomy performed. Histopathologic diagnoses included adenocarcinoma (21 cats), lymphoma (19), mast cell tumor (4), and neuroendocrine carcinoma (2). CLINICAL IMPLICATIONS: Obtaining clean margins at surgery seems to increase survival time in cats with malignant colonic neoplasia. Metastasis at the time of surgery decreases survival time. Data from this study indicate that the survival time of certain cats with colonic lymphoma may not be affected by chemotherapy. Cats with an unidentified colonic mass should receive a subtotal colectomy to increase survival time. Cats with colonic adenocarcinoma should receive a subtotal colectomy with consideration of doxorubicin administration to increase survival time.

Spinal tumors in 37 dogs: clinical outcome and long-term survival (1987-1994).

The current management of dogs with spinal canal neoplasia in a large veterinary institution was evaluated. Postoperative survival time and prognostic indicators for survival were examined. Spinal neoplasms in dogs and humans also were compared. Thirty-seven cases with histologically confirmed spinal tumors were included in the study. The cervical region was affected most commonly, and 23 (62%) of 37 cases had extradural tumors. A hemilaminectomy or a dorsal laminectomy was performed in each case; three cases received adjuvant treatment. Twelve (32%) cases were euthanized at the time of surgery, and two died immediately after surgery. One dog was euthanized 20 days after surgery because of persistent clinical signs. Twenty-two cases were followed postoperatively; nine different types of primary tumors were confirmed by histological examination of tissue specimens from these 22 cases, and three cases had metastatic lesions. The median survival time of these 22 cases was 240 days. Twelve (32%) of the 37 cases had nerve-sheath tumors; the median survival time for these 12 cases was 180 days. No prognostic indicators were identified. However, median survival times of cases with benign versus malignant tumor types were 1,410 days and 180 days, respectively (p of 0.07). Four cases each had a myxoma/myxosarcoma, a tumor previously unreported in the spinal canal in dogs.

Soft tissue sarcomas.

The soft tissue sarcomas (STS) constitute approximately 15% of all canine and 7% of all feline skin and subcutaneous tumors. STS are tumors that arise from a variety of mesenchymal tissues. The aggressive nature of STS in cats, especially those tumors occurring after vaccination, suggests that novel therapies should be investigated.

Correlation between serum creatine kinase activities and anorexia in cats.

There are no available biochemical analyses that will reliably identify malnourished cats or enable monitoring them during supportive alimentation. Studies in people indicate that creatine kinase (CK) activity is high in malnourished patients and may decrease in response to nutritional intervention. The purpose of this study was to determine the value of quantifying serum CK activities in anorectic cats and to assess the usefulness of this test in monitoring nutritional support in these patients. Serum CK activity was evaluated in nonanorectic cats (Group 1, n = 25), and in hospitalized, anorectic cats that received nutritional support through a nasoesophageal tube (Group 2, n = 25). Anorectic cats had a significantly higher serum CK activity (median = 2,529 U/ L, range 88 to 153,000 U/L) than the control group (median = 175 U/L, range 81 to 363 U/L, P < .001). There were significant positive correlations between serum CK and both aspartate transaminase (AST) (P < .05; r = .59) and lactate dehydrogenase (LDH) (P < .05; r = .41) activities. Serum CK activity was significantly lower in anorectic cats after 48 hours of nutritional support than at time 0 (P < .001) and eventually returned to normal with continued support. Serum CK activity may serve as a useful marker in assessing and monitoring nutritional status in cats.

A prospective study of radiation therapy for the treatment of grade 2 mast cell tumors in 32 dogs.

Surgery, chemotherapy, and irradiation have been used singly or in combination to treat dogs with cutaneous grade-2 mast cell tumors (MCT). However, optimal treatment has not been established. At The Animal Medical Center, 32 dogs with grade 2, stage 0 MCT received cobalt radiation treatment to a dose of 54 Gy; 94% had a disease-free interval of 1 year. The 2-,3-,4-, and 5-year disease-free intervals were 86%. Survival rates were 100% for 1 year and 96% for 2 to 5 years, with only 1 death caused by MCT. Primary site was not a prognostic factor for survival in this study. Minimal toxicity was observed and was limited to acute cutaneous reactions. Late-term reactions to radiation therapy were mild and considered acceptable in all cases. No deaths occurred due to treatment, and no dog was eliminated from the study because of radiation therapy toxicity. Radiation therapy appears to be an effective treatment for dogs with grade 2, stage 0 MCT.

Radiation therapy: a radiation oncologist's point of view.

This article is intended as a clinical introduction to radiation therapy as a treatment modality. It discusses the indications and contraindications for radiotherapy. Additionally, it attempts to cover the expected response of a wide variety of tumors to radiation. It should be remembered that veterinary radiotherapy is still in its infancy, and that much of the information presented in this article is, unfortunately, anecdotal in nature.