Hypercalcemia in cats: a retrospective study of 71 cases (1991-1997)

A retrospective study was conducted to characterize the diseases, clinical findings, and clinicopathologic and ultrasonographic findings associated with hypercalcemia (serum calcium concentration >11 mg/dL) in 71 cats presented to North Carolina State University Veterinary Teaching Hospital. The 3 most common diagnoses were neoplasia (n = 21), renal failure (n = 18), and urolithiasis (n = 11). Primary hyperparathyroidism was diagnosed in 4 cats. Lymphoma and squamous cell carcinoma were the most frequently diagnosed tumors. Calcium oxalate uroliths were diagnosed in 8 of 11 cats with urolithiasis. Cats with neoplasia had a higher serum calcium concentration (13.5 ± 2.5 mg/dL) than cats with renal failure or urolithiasis and renal failure (11.5 ± 0.4 mg/dL; P <.03). Serum phosphorus concentration was higher in cats with renal failure than in cats with neoplasia ( P < .004). Despite the fact that the majority of cats with uroliths were azotemic, their serum urea nitrogen and creatinine concentrations and urine specific gravity differed from that of cats with renal failure. Additional studies are warranted to determine the underlying disease mechanism in the cats we identified with hypercalcemia and urolithiasis. We also identified a small number of cats with diseases that are not commonly reported with hypercalcemia. Further studies are needed to determine whether an association exists between these diseases and hypercalcemia, as well as to characterize the underlying pathophysiologic mechanism for each disease process.     

Primary hyperparathyroidism in cats: seven cases (1984-1989).

The medical records of 7 hypercalcemic cats with primary hyperparathyroidism were evaluated. Mean age was 12.9 years, with ages ranging from 8 to 15 years; 5 were female; 5 were Siamese, and 2 were of mixed breed. The most common clinical signs detected by owners were anorexia and lethargy. A cervical mass was palpable in 4 cats. Serum calcium concentrations were 11.1 to 22.8 mg/dl, with a mean of 15.8 mg/dl calculated from each cat's highest preoperative value. The serum phosphorus concentration was low in 2 cats, within reference limits in 4, and slightly high in 1 cat. The BUN concentration was greater than 60 mg/dl in 2 cats, 31 to 35 mg/dl in 2 cats, and less than 30 mg/dl in 3 cats. Abnormalities were detected in serum alanine transaminase, aspartate transaminase, and alkaline phosphatase activities from 2 or 3 cats. Parathormone (PTH) concentrations were measured in 2 cats before and after surgery. The preoperative PTH concentration was within reference limits in 1 cat and was high in 1 cat. The PTH concentrations were lower after surgery in both cats tested. A solitary parathyroid adenoma was surgically removed from 5 cats, bilateral parathyroid cystadenomas were surgically resected in 1 cat, and a parathyroid carcinoma was diagnosed at necropsy in 1 cat. None of the cats had clinical problems with hypocalcemia after surgery, although 2 cats developed hypocalcemia without tetany, one of which was controlled with oral administration of dihydrotachysterol and the other with oral administration of 1,25 dihydroxyvitamin D. All 5 of the cta that underwent removal of an adenoma were alive at least 240 days after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)     

A trial of 13-cis-retinoic acid for treatment of squamous cell carcinoma and preneoplastic lesions of the head in cats

Ten cats with a total of 15 cancerous or precancerous lesions were examined for clinical response to and histopathologic changes after treatment with 13-cis-retinoic acid. Before treatment was started, the lesions were graded according to clinical severity and biopsied for histopathologic examination. Serum samples were prepared for determining vitamin A concentrations. For comparison, serum vitamin A concentrations in 10 clinically healthy cats were determined. 13-cis-Retinoic acid (approx 3.0 mg/kg) was given to affected cats once a day for an average of 68 days. At the completion of the therapeutic trial, additional biopsy tissues were obtained for histopathologic examination, and serum was assayed for 13-cis-retinoic acid. Of the 15 lesions examined, only 1 showed partial clinical and microscopic improvement during the therapy period. The mean serum vitamin A concentration of the affected cats was not statistically different from that of the 10 healthy cats. The results of this trial indicated that 13-cis-retinoic acid used at this dosage, daily frequency, and duration did not have therapeutic efficacy for squamous cell carcinomas or preneoplastic lesions in the cat and that the mean serum vitamin A concentration did not differ between the affected cats and clinically healthy cats.     

Hypercalcemia associated with rodenticide poisoning in three cats

Hypercalcemia (12.0 to 18.3 mg/dl) was detected in 3 cats that had eaten a rodenticide that contained cholecalciferol. Clinical signs included lethargy, anorexia, vomiting, and polydipsia. Treatment with furosemide and fluids administered IV resulted in normalization of the serum calcium concentration and in remission of the clinical signs in 2 cats. One cat with a serum calcium concentration of 18.3 mg/dl did not have clinical signs, was not treated, and was reportedly normal 9 months after initial examination. We attributed the uniformly favorable outcome of exposure to the rodenticide in these cats to the small quantity of the toxin ingested.     

Preclinical study in cats of the pro-photosensitizer 5-aminolevulinic acid

OBJECTIVE: To determine whether feline cells were able to convert 5-aminolevulinic acid (ALA) to protoporphyrin IX (PpIX) in vivo and in vitro, whether i.v. administration of ALA to healthy cats resulted in adverse effects, and whether PpIX accumulated in a squamous cell carcinoma (SCC) of a cat. ANIMALS: 4 healthy adult cats and 1 adult cat with a cutaneous SCC. PROCEDURE: In vitro production of PpIX was determined by incubating Crandell feline kidney cells with ALA. Effects of ALA administration and in vivo production of PpIX were determined by administering ALA (100, 200, or 400 mg/kg of body weight) to healthy cats and collecting skin biopsy specimens for up to 24 hours after drug administration. Blood samples were collected for CBC and serum biochemical analyses, and necropsies were performed. Accumulation of PpIX in a SCC was determined by treating a cat with a facial SCC with ALA and collecting specimens of the tumor and adjacent grossly normal skin. RESULTS: Incubation of ALA with feline cells resulted in time- and dose-dependent cytoplasmic accumulation of PpIX in vitro. After i.v. ALA administration, PpIX was detected in all tissues examined, with the highest fluorescence intensity in epithelia and in squamous cell carcinoma. The tumor-to-skin fluorescence intensity ratio was 5. All cats developed hepatotoxicoses. CONCLUSIONS AND CLINICAL RELEVANCE: Results from this limited number of cats suggest that ALA may be a useful photosensitizer in cats, but that doses > 100 mg/kg, i.v., may not be safe.     

Serum hyperviscosity syndrome associated with multiple myeloma in two cats.

Serum hyperviscosity syndrome was diagnosed in 2 cats with multiple myeloma. Clinical signs included pale mucous membranes, dehydration, retinal hemorrhages, dilated and tortuous retinal vessels, seizures, head-tilt, nystagmus, systolic murmur, and gallop rhythm. Laboratory abnormalities included hyperglobulinemia, azotemia, hyperphosphatemia, nonregenerative anemia, and thrombocytopenia. Both cats had IgG monoclonal gammopathy, Bence Jones proteinuria, increased numbers of bone marrow plasma cells, and high values for relative serum viscosity. Renal disease was suspected in both cats. Cardiac hypertrophy was documented in 1 cat and was suspected in the other cat. Chemotherapy, using melphalan, prednisone, and vincristine, caused short-term remission in both cats, and plasmapheresis was used to lower serum protein concentration in 1 cat. Serum hyperviscosity syndrome rarely develops in cats, but should be suspected when monoclonal gammopathy exists with signs of neurologic, cardiac, or retinal disease.     

Serum feline trypsin-like immunoreactivity in cats with exocrine pancreatic insufficiency

Exocrine pancreatic insufficiency is thought to occur rarely in cats. This assumption has been made based on the lack of a specific test for this disease in the cat. Clinical data from the 1st 20 cats with serum feline trypsin-like immunoreactivity (fTLI) concentrations < or = 8 microg/L are presented. In 17 of these 20 cats compelling evidence for a diagnosis of exocrine pancreatic insufficiency (EPI) was present and in the remaining 3 supportive evidence for a diagnosis of EPI was available. The conclusion was made that serum fTLI concentration is a specific test for EPI in the cat.     

Transient clinical diabetes mellitus in cats: 10 cases (1989-1991)

Medical records of 10 cats with transient clinical diabetes mellitus were reviewed. At the time diabetes was diagnosed, clinical signs included polyuria and polydipsia (10 cats), weight loss (8 cats), polyphagia (3 cats), lethargy (2 cats), and inappetence (1 cat). Mean (+/- SD) fasting blood glucose concentration was 454 +/- 121 mg/dL, mean blood glucose concentration during an 8-hour period (MBG/8 hours) was 378 +/- 72 mg/dL, and glycosuria and trace ketonuria were identified in 10 and 5 cats, respectively. Baseline serum insulin concentration was undetectable (6 cats) or within the reference range (4 cats) and serum insulin concentration did not increase after i.v. glucagon administration in any cat. Insulin-antagonistic drugs were being administered to 5 cats and concurrent disorders were identified in all cats. Management of diabetes included administration of glipizide (6 cats), insulin (3 cats), or both (1 cat), discontinuation of insulin-antagonistic drugs, and treatment of concurrent disorders. Insulin and glipizide treatment was discontinued 4-16 weeks (mean, 7 weeks) after the initial diagnosis of diabetes was confirmed. At the time treatment for diabetes was discontinued, clinical signs had resolved, mean fasting blood glucose concentration was 102 +/- 48 mg/dL, MBG/ 8 hours was 96 +/- 32 mg/dL, glycosuria and ketonuria were not identified in any cat, and concurrent disorders (except mild renal insufficiency in 1 cat) had resolved. Significant (P < .05) increases occurred in postglucagon serum insulin concentrations, insulin peak response, and total insulin secretion, compared with values obtained when clinical diabetes was diagnosed. Histologic abnormalities were identified in pancreatic islets of 5 cats in which pancreatic biopsies were obtained and included decreased number of islets (4 cats), islet amyloidosis (3 cats), and vacuolar degeneration of islet cells (3 cats). Mean beta cell density was significantly (P < .001) decreased in diabetic cats compared with control cats (1.4 +/- 0.7 versus 2.6 +/- 0.5%, respectively). Cells within islets stained positive for insulin, however, the number of insulin-staining cells per islet and the intensity of insulin staining were decreased in 5 and 2 cats, respectively. Clinical diabetes had not recurred in 1 cat after 6 years, in 4 cats lost to follow-up after 1.5, 1.5, 2.0, and 2.5 years, and in 2 cats that died 6 months and 5.5 years after clinical diabetes resolved. Clinical diabetes recurred in 3 cats after 6 months, 14 months, and 3.4 years, respectively. These findings suggest that cats with transient clinical diabetes have pancreatic islet pathology, including decreased beta cell density, and that treatment of diabetes and concurrent disorders results in improved beta cell function, reestablishment of euglycemia, and a transition from a clinical to subclinical diabetic state.     

A phase I clinical trial evaluating imatinib mesylate (Gleevec) in tumor-bearing cats

A phase I clinical trial evaluating the toxicity of orally-administered imatinib mesylate was performed in 9 tumor-bearing cats. Imatinib is a small molecule, tyrosine kinase inhibitor, which selectively blocks the function of overexpressed proteins associated with various malignancies. Cats included in the study had diagnoses of fibrosarcoma, squamous cell carcinoma, and mast cell tumor, and each cat was staged using CBC and serum biochemistry; urinalysis, thoracic radiographs, and abdominal ultrasonography were performed in some cats. Most cats were treated previously by surgery, radiation therapy, chemotherapy, or some combination of these treatments. None of the cats received any concurrent chemotherapy. Six cats were treated with imatinib mesylate at 1-2 mg/kg PO q24h. Dose escalations were made to 2, 4, and 10 mg/kg PO q24h in 5 cats. Two cats started therapy at 10 mg/kg PO q24h, and 1 cat started therapy at 15 mg/kg PO q24h; all 3 cats remained at these dosages. No signs of toxicity, as evaluated by CBC and serum biochemistry, were noted in 8 of the 9 cats, and minimal gastrointestinal toxicity was observed. Due to the low frequency of adverse effects, further evaluation of imatinib is ongoing at a dosage of 10 mg/kg PO q24h.     

Serum cobalamin concentrations in healthy cats and cats with non-alimentary tract illness in Australia

Objective   To determine a reference range for serum cobalamin concentration in healthy cats in Australia using a chemiluminescent enzyme immunoassay and to prospectively investigate the prevalence of hypocobalaminaemia in cats with non-alimentary tract disease.
Design   Prospective study measuring serum cobalamin concentrations in clinically healthy cats and cats with non-alimentary tract illness.
Procedure   Blood was collected from 50 clinically healthy cats that were owned by staff and associates of Veterinary Specialist Services or were owned animals presented to Creek Road Cat Clinic for routine vaccination. Blood was collected from 47 cats with non-alimentary tract illness presented at either clinic. Serum cobalamin concentration was determined for each group using a chemiluminescent enzyme immunoassay.
Results   A reference range for Australian cats calculated using the central 95th percentile in the 50 clinically healthy cats was 345 to 3668 pg/mL. Median serum cobalamin concentration in 47 cats with non-alimentary tract illness (1186 pg/mL; range 117–3480) was not significantly different to the median serum cobalamin of the 50 healthy cats (1213 pg/mL, range 311–3688). Using the calculated reference range one sick cat with non-alimentary tract illness had a markedly low serum cobalamin concentration.
Conclusion   Although hypocobalaminaemia is uncommon in sick cats with non-alimentary tract illness in Australia, its occurrence in this study warrants further investigation.     

Use of percutaneous ethanol injection for treatment of bilateral hyperplastic thyroid nodules in cats

OBJECTIVE: To determine the efficacy and safety of percutaneous ethanol injection (PEI) for the treatment of hyperthyroidism caused by bilateral hyperplastic thyroid nodules in cats. DESIGN; Prospective study. ANIMALS: 7 cats. PROCEDURE: Hyperthyroidism was diagnosed on the basis of clinical signs and increased serum total thyroxine (TT4) concentrations. The presence of 2 cervical thyroid nodules was confirmed by use of ultrasonography and technetium Tc 99m albumin thyroid scans. After the death of 1 cat that received PEI in both thyroid nodules at the same time, the protocol was changed to injecting ethanol into 1 nodule at a time, with at least 1 month between injections. Clinical signs, serum TT4 concentrations, serum ionized calcium concentrations, laryngeal function, findings on ultrasonographic examinations of the ventral cervical region, and results of thyroid scans were monitored. RESULTS: Serum TT4 concentrations transiently decreased in all 6 cats (into the reference range in 5 of 6 cats) within 4 days of the first staged ethanol injection. Each subsequent injection resulted in a transient decrease in serum TT4 concentration. The longest period of euthyroidism was 27 weeks. Adverse effects included Horner's syndrome, dysphonia, and laryngeal paralysis. One cat died of unrelated causes. One cat underwent bilateral thyroidectomy, 2 cats were treated with methimazole, and 2 cats that had increased serum TT4 concentrations were not treated further, because they remained clinically normal. CONCLUSIONS AND CLINICAL RELEVANCE: Percutaneous ethanol ablation of bilateral thyroid nodules as a treatment for cats with hyperthyroidism is not recommended. This treatment is not as efficacious as the medical and surgical treatments presently used.     

Treatment of mandibular squamous cell carcinoma in cats by use of mandibulectomy and radiotherapy: seven cases (1987-1989).

Seven cats with squamous cell carcinoma involving the mandible were treated by surgery and radiotherapy. Surgery consisted of hemimandibulectomy or combined rostral and hemimandibulectomy, gastrostomy tube placement, and submandibular lymph node excisional biopsy. Radiotherapy (orthovoltage or 60Co) commenced 2 weeks after surgery. Histologically, the tumor invaded surgical margins in 6 of 7 cats. Nerve infiltration was histologically identified in 2 cats. All cats had stage-3 disease with radiographic evidence of mandibular bone involvement. Age ranged between 8 and 16 years (median, 10 years). Hypercalcemia (2), feline immunodeficiency virus (2), and hyperthyroidism (1), were detected in cats prior to treatment. Survival after surgery was a median of 14 months (range = 3 to 36 months, mean = 15 months). Six cats were euthanatized because of recurrence of disease at 3, 7, 9, 16, 21, and 36 months. One cat was euthanatized at 14 months because of an unrelated disease. Complications of tongue lagging, drooling after meals, mandibular drift, maxillary ulceration, and alopecia of the jaw developed in a few cats. Radiation at the primary site and regional lymph nodes after surgery of curative intent extended survival in cats with mandibular squamous cell carcinoma.     

Effect of sodium bicarbonate infusions on ionized calcium and total calcium concentrations in serum of clinically normal cats

The effects of sodium bicarbonate (0.5 mEq/kg of body weight, 1.0 mEq/kg, 2.0 mEq/kg, and 4.0 mEq/kg) on ionized and total calcium concentrations were determined in clinically normal cats. Also, serum pH, whole blood pH, and serum albumin, serum total protein, and serum phosphorus concentrations were measured. Intravenous administration of sodium bicarbonate to awake cats decreased serum ionized calcium and serum total calcium concentrations. All dosages of sodium bicarbonate were associated with significant decreases of serum ionized calcium concentration. This effect lasted for greater than 180 minutes when cats were given 2.0 mEq/kg or 4.0 mEq/kg. When cats were given 4 mEq of sodium bicarbonate/kg, serum ionized calcium concentration was significantly decreased, compared with that when cats were given lower doses, but only at 10 minutes after infusion. After sodium bicarbonate infusion, serum total calcium concentration, measured by ion-specific electrode and colorimetry, was lower than baseline values at most of the times evaluated. Decreases in serum ionized calcium and serum total calcium concentrations can be attributed only in part to an increase in serum or whole blood pH and to a decrease in serum protein concentration. Serum total calcium concentrations measured by ion-specific electrode and by colorimetry were positively correlated, but the variability was high. Only 44% of the variability in serum ionized calcium concentration could be predicted when serum total calcium, albumin, total protein, phosphorus, and bicarbonate concentrations and pH were considered.     

Polycythemia vera in a cat with cardiac hypertrophy

Polycythemia vera, a rare and poorly documented disease in cats, was diagnosed in a 4-year-old domestic shorthair cat admitted because of seizures. The diagnosis was made on the basis of high PCV, normal serum erythropoietin concentration (as determined by bioassay, using rabbit bone marrow cells), and elimination of secondary polycythemia as a diagnosis. Cardiac hypertrophy, which might have been secondary to blood hyperviscosity, also was diagnosed. The cat has been treated by periodic phlebotomy and has been without clinical signs of disease for more than 20 months.     

Adenocarcinoma of the middle ear with osteolysis of the tympanic bulla in a cat.

Peripheral vestibular disease and lethargy were attributed to an adenocarcinoma in the middle ear of a 10-year-old cat. The tumor was invasive, inducing severe lysis of the tympanic bulla and adjacent temporal bone. Direct invasion to the meninges and brainstem also was observed. Neoplasms of the middle ear are rare in cats, with squamous cell carcinomas reported most commonly, but should be considered as causes of chronic otitis or signs of peripheral vestibular disease.     

Feline head and neck squamous cell carcinoma: a natural model for the human disease and development of a mouse model

Head and neck squamous cell carcinoma (H/N SCC) is a devastating disease in humans and cats, and shares similar features between the two species. The large population of pet cats inthe United States, along with the high incidence of oral SCC in the cat, makes the cat an attractive candidate as a natural model for the human disease. There are similarities in pathology, progression, outcome, resistance to treatment, possible aetiologies and p53 expression, and we discuss the benefits of the cat as a natural model. We describe the development of a nude mouse xenograft model of feline oral SCC using the SCCF1 cell line transfected with a luciferase expression construct. In vivo tumour growth and metastasis were measured using serial bioluminescent imaging, and tumours grew best in the subcutis. The cat and nude mouse models will be useful to investigate the pathogenesis and the molecular basis of H/N SCC, and for preclinical drug screening.     

Resolution of renal adenocarcinoma-induced secondary inappropriate polycythaemia after nephrectomy in two cats

Two cases of secondary, inappropriate polycythaemia caused by renal adenocarcinoma in domestic shorthair cats, are described. The cats were 9 and 12 years old and both were presented because of generalised seizures presumably due to hyperviscosity. Both cats had a markedly increased haematocrit (0.770 and 0.632 l/l) and thrombocytosis (744 x 10(9)/l and 926 x 10(9)/l). An abdominal ultrasound revealed a mass in the cranial pole of one kidney in both cats. Serum erythropoietin (EPO) concentration was within the reference interval (RI) in both cats but was inappropriately high considering the markedly increased haematocrit. The cats were initially stabilised and managed by multiple phlebotomies and intravenous fluid therapy and underwent nephrectomy of the affected kidney later on. Both the polycythaemia and thrombocytosis resolved following surgery. Postoperative serum EPO concentration, measured in one cat, decreased markedly. Histopathology of the affected kidneys confirmed a diagnosis of renal adenocarcinoma. Both cats were stable for an 8-month follow-up period; however, one cat had developed a stable chronic kidney disease (CKD), while the other was represented 8 months postoperatively due to dyspnoea, and had radiographic evidence of lung metastasis, presumably because of the spread of the original renal tumour and was euthanased. Initial stabilisation of polycythaemic cats should include multiple phlebotomies. Nephrectomy should be considered in cats with secondary, inappropriate, renal adenocarcinoma-related polycythaemia when only one kidney is affected by the tumour, and provided that the other kidney's function is satisfactory. Nephrectomy should be expected to resolve the polycythaemia and lead to normalisation of serum EPO concentration.     

Phase I clinical trial evaluating STI571 in tumor bearing cats

Introduction: STI571 (Gleevec, imatinib mesylate) is a receptor tyrosine kinase inhibitor with selectivity for Bcr‐Abl, platelet‐derived growth factor (PDGF), stem cell factor (SCF), and c‐Kit. Side effects with use in humans include vomiting, diarrhea, nausea, myalgia, edema, and cutaneous reactions. Renal and hepatic toxicity have also been reported. In dogs, there is significant hepatic toxicity at sub‐clinical doses. The purpose of this prospective study was to determine the toxicity level and potential treatment protocol in tumor bearing cats. Methods: A phase I clinical trial was performed in client owned cats using an escalating dose of STI571 in tumor bearing cats. Cats included in the study had a histologic diagnosis of fibrosarcoma or other tumors and were staged with CBC, biochemical profile, thoracic radiographs, and abdominal ultrasound. None of the cats received concurrent chemotherapy, but those previously treated with surgery, radiation therapy, or chemotherapy, were not excluded. The initial starting dose was 5 mg/cat PO SID and was gradually increased to 10 and 20 mg/cat PO SID at a 2–6 week interval depending on laboratory work and disease progression. A repeat physical examination, CBC, and biochemical profile, were performed every 2 weeks for 2 rechecks, then every 4 weeks. Results: Six cats were enrolled in the study. Four cats had oral squamous cell carcinoma, and two cats had cutaneous fibrosarcoma. One cat demonstrated leukocytosis, increased liver enzymes, and signs of acute renal failure two weeks after initiating therapy (5 mg PO SID). No dose escalation was made in this cat. Five cats endured dose escalations of 10 mg PO SID in two cats and 20 mg PO SID in three cats and were treated for 2–4 months. None of these cats experienced any signs of toxicity as measured by CBC and biochemical profile. Conclusions: Only one cat experienced toxicity that may have been associated with low dose administration of STI571. As most cats tolerated the drug without an adverse effect, further evaluation of STI571 in a phase II clinical trial is warranted.     

Intraepidermal adenocarcinoma in the perianal skin of two cats, a condition resembling human extramammary Paget's disease

In humans, mammary and extramammary Paget's disease is an uncommon to rare manifestation of intraepidermal adenocarcinoma arising from simple epithelium, usually glandular in origin. This report describes two cats with lesions in perianal skin consisting of atypical intraepidermal neoplastic cells. Differential diagnoses included intraepidermal adenocarcinoma, in situ squamous or basal cell carcinoma, junctional amelanotic melanoma, and epitheliotropic tumours of histiocytic or lymphocytic origin. The atypical intraepidermal cells in the cats were immunohistochemically positive for cytokeratin 8/18 (CK8/18), which stains simple (glandular) epithelium. The keratinocytes and basal cells were negative for CK8/18. In addition, the atypical intraepidermal cells were immunohistochemically negative for melanocytic, lymphocytic, and histiocytic markers. The staining results confirmed the atypical intraepidermal cells to be of simple glandular origin, and ruled out other causes of intraepidermal malignancy. In one cat the clinical lesions consisted of a pruritic erythematous eruption surrounding the anus. Another cat presented clinically for an area of irregular anal thickening; this cat had well-regulated diabetes mellitus. The cats were otherwise clinically healthy. The clinical features, histological appearance, and immunohistochemical staining of the skin lesions were consistent with those described for human perianal extramammary Paget's disease. To the authors' knowledge, this is the first report of an intraepidermal adenocarcinoma in a cat or other animal species.     

Beta cell and insulin antibodies in treated and untreated diabetic cats

Beta cell and insulin antibodies are involved in the pathogenesis of diabetes in human patients. Beta cell antibodies have also been found in about 50% of newly diagnosed diabetic dogs. This study's objective was to examine these antibodies' role in feline diabetes. The serum of 26 newly diagnosed untreated diabetic cats, 29 cats on insulin therapy, 30 cats with diseases other than diabetes, and 30 healthy cats was examined for beta cell and insulin antibodies. For beta cell antibody testing, purified beta cells from a radiation-induced transplantable rat insulinoma were used. Serum from cats in which anti-beta cell antibodies were induced by injecting a purified beta cell suspension subcutaneously was used as a positive control. Following incubation with test sera, fluorescein-labeled anti-cat immunoglobulins were used to visualize binding between the beta cells and cat gamma globulins. Each serum was tested on two different tumor preparations. For the detection of insulin antibodies, a charcoal separation method was used. It was found that none of the healthy cats, none of the newly diagnosed, untreated diabetic cats and none of the cats with diseases other than diabetes had antibodies against beta cells or against endogenous insulin. Four diabetic cats (14%) that had been treated with different insulin preparations had insulin antibodies.It is concluded that immune-mediated processes are not causing diabetes in the cat. Further studies are needed to evaluate if antibodies directed against exogenous insulin alter the response of diabetic cats to insulin.