Evaluation of cardiac rhythm in dogs treated with levamisole hydrochloride using 24-hour ambulatory electrocardiography

The objective of this study was to evaluate the electrocardiographic alterations in the cardiac rhythm in dogs treated with levamisole hydrochloride over a period of 24 hours. Thirty-six mixed-breed dogs, both male and female, all clinically healthy, were used in the experiment. The dogs were divided into 6 groups with 6 dogs in each group, according to dosage and route of administration. The Holter test was initiated immediately after the treatment, and was maintained for 24 hours. In the group treated with 10 mg/kg by way of subcutaneous injection, one of them showed ventricular premature complexes, sometimes isolated and other times in pairs, and ventricular tachycardia, concentrated mainly in the first hour after administration of the drug. In the group of 6 animals treated subcutaneously with 25mg/kg, four showed isolated ventricular premature complexes, ventricular bigeminy and trigeminy, mainly during the first 2 hours after administration of the drug. All the animals in the other groups showed sinus arrhythmia followed by sinus arrest. The disturbances in the cardiac rhythm observed in clinically healthy animals treated with levamisole hydrochloride, indicate that it is preferable to avoid subcutaneous administration of levamisole hydrochloride and that the oral administration of the drug should be done with caution.     

Nervous disorders in dogs associated with levamisole therapy

The onset of nervous disorders associated with levamisole hydrochloride therapy is described in five dogs. Distemper and granulomatous encephalomyelitis were diagnosed in four cases. Possible stimulation of the cellular immune response by levamisole, with resultant secondary tissue damage, was believed to be associated with the time of onset and the severity of these disorders. The neuronal degeneration in the fifth case was not consistent with an inflammatory disorder. The possible role of levamisole in this case is unknown.     

Rabies-like inclusions in dogs

Inclusion bodies, indistinguishable from rabies inclusion bodies (Negri bodies), were found in the brains of 8 nonrabid dogs. The inclusions were compared to Negri bodies present in neurons of rabies-positive animals and examined for the presence of rabies virus by a combination of immunoperoxidase staining (7 cases), fluorescent antibody (FA) staining (1 case), and transmission electron microscopy (4 cases). Positive immunoperoxidase staining for rabies was obtained in brain tissues from FA rabies-positive animals. All brain tissues from the 7 dogs stained by the immunoperoxidase method and the brain from the 1 dog stained by the FA method were negative for rabies. Rabies virus was not found in inclusion-containing neurons in the cases examined by transmission electron microscopy. These results emphasize the importance of FA testing and mouse inoculation for the diagnosis of rabies.     

Hepatopathy in 4 dogs treated with amiodarone

Amiodarone is a class III antiarrhythmic drug used in dogs with dilated cardiomyopathy and ventricular tachyarrhythmias. Hepatopathy is one of the more commonly reported adverse effects of amiodarone use in people. We describe 4 dogs that developed hepatopathy associated with amiodarone administration; 2 dogs also developed neutropenia. Three dogs had clinical signs of anorexia and lethargy; 1 did not show signs until impaired liver function had developed. Clinical signs or biochemical abnormalities developed 1.5-8 months after amiodarone treatment was started. Clinical signs resolved within 2 weeks of discontinuing amiodarone, but biochemical abnormalities did not resolve for 6-8 weeks. The delay between onset of liver disease and overt clinical signs suggests that serial evaluation of liver enzyme activities following amiodarone use in does is important.     

Hypothyroid dogs treated with intravenous levothyroxine

The purpose of this retrospective study was to report clinical and clinicopathologic findings, response to treatment, and outcome of hypothyroid dogs treated with levothyroxine intravenously (IV). Seven levothyroxine IV treated hypothyroid dogs and 799 other hypothyroid dogs examined during the same period were included. Rottweiler dogs were overrepresented in the group of levothyroxine IV-treated hypothyroid dogs compared with other hypothyroid dogs (P < .0001). Common physical examination abnormalities were obese or overweight body condition (5 dogs), mental dullness (5 dogs), and nonpitting edema (4 dogs). Anemia (4 dogs) and hypercholesterolemia (5) were common, although 1 dog had neither. Concurrent disease (most commonly infection) was observed in 5 dogs. Glucocorticoids and nonsteroidal antiinflammatory drugs had been administered to 2 dogs before examination. Surgery was performed in 2 dogs before treatment with levothyroxine IV. Four of the 7 dogs received 4-5 microg/kg of levothyroxine IV. Subjective improvement in mentation or ambulation (6 of 7 dogs) and systolic hypotension (2 of 2 dogs) occurred within 30 hours of levothyroxine IV administration. Six of the 7 dogs responded well to therapy and were discharged from the hospital. It was concluded that physical examination and clinicopathologic findings of dogs with a hypothyroid crisis are nonspecific, although Rottweiler dogs may be at increased risk. Concurrent disorder, such as infection, concurrent administration of thyroid hormone-altering medication, and surgery, may be associated with development of a hypothyroid crisis. Resolution of abnormal mentation, ambulation, and systolic hypotension should be expected within 30 hours. Prognosis is good in most treated dogs.     

Acanthomatous ameloblastoma in dogs treated with intralesional bleomycin

Acanthomatous ameloblastoma (AA) is a benign gingival tumour that often invades bone. This retrospective study evaluated the efficacy of intralesional (IL) bleomycin as a treatment for AA. Six dogs received weekly or bimonthly IL bleomycin injections (dose range, 10–20 U m^?2). A seventh dog presented with advanced, nonresectable AA was treated palliatively. One to sixteen treatments were administered (median, 5). Six of the seven dogs had a complete response within 4 months from initial IL injection (median, 1.5 months), whereas the palliative case had approximately 25% decrease in tumour volume 14 days from initial injection. Local recurrence was not observed during the study period, with a median follow‐up time of 842 days. Adverse effects were limited to wound formation with bone exposure (n = 4), mild tissue reactions (n = 3), local swelling (n = 2) and local infection (n = 1). The conclusions of this study show IL bleomycin is an effective treatment for canines with AA.     

左旋咪唑对犬外周血T淋巴细胞转化的影响

左族咪唑又名左咪唑、左旋四咪唑，是人工合成的广谱驱虫药。本品具有旋光性，为噻咪唑左旋异构体，常用其盐酸盐(盐酸左旋咪唑)，为白色或微带黄色晶粉，性质稳定，易溶于水(25C：62．7％)，酸性水溶液中稳定。本品对体内多种寄生虫如蛔虫、肺丝虫、钩虫等具有强大的驱杀作用，并且给药方便，可皮下     

The effects of levamisole poisoning on the haematological and biochemical parameters in dogs

This study was designed to evaluate possible organ and system disorders associated with experimentally induced levamisole poisoning in dogs. For this purpose, twelve clinically healthy dogs of different ages, sexes and breeds were used. They were divided into two equal groups (Group A and Group B) and given levamisole orally at a dose of 25 mg/kg of body weight daily for three days. The dogs in Group B were also injected with atropin sulphate (0.04 mg/kg of body weight) subcutaneously (sc) 1 hour after each administration of levamisole. Routine clinical examinations were made and some haematological, biochemical and blood gas parameters were established at various times after administration of levamisole. The dogs in Group A developed severe neurological signs, gastric haemorrhage, bloody vomiting, colic, anaemia and four dogs died. In Group B these signs were mild and only one dog died. Levamisole poisoning was characterised by a significant reduction in the total number of red blood cells (RBCs), concentration of haemoglobin (Hb) and packed cell volume (PCV), and by anaemia. Peripheral blood pH, actual bicarbonate of plasma (HCO3), actual base excess (BE), partial pressure of oxygen (pO2) and saturated oxygen (O2SAT) increased in both groups of animals and these dogs developed metabolic alkalosis 48 hours after the first administration of levamisole. The results of the study also show that levamisole poisoning in dogs causes a significant increase in the activity of serum alanine aminotransferase (ALT) and of alkaline phosphatase (AP) and in the concentration of urea in both Group A and Group B. In the study, atropin sulphate reduced the severity of the clinical signs and the number of deaths, but it was not alone sufficient to remedy levamisole poisoning in dogs.     

Intranasal melanoma treated with radiation therapy in three dogs

Three dogs were investigated for chronic unilateral nasal discharge. In all cases CT imaging showed an intranasal mass causing turbinate lysis and no evidence of metastasis. Cytology in cases 1 (a 14-year-old neutered male crossbreed dog) and 2 (a five-year-old neutered male German Shepherd dog) demonstrated a pleomorphic cell population with variable intracellular pigment suspicious of melanocytic neoplasia. Histopathology with immunohistochemistry (Melan-A and vimentin, plus PNL-2 in one case) confirmed the diagnosis of melanoma in all dogs. All dogs were treated with megavoltage radiotherapy using linear accelerators. Cases 1 and 3 (a nine-year-old neutered female beagle dog) received a hypofractionated (4 × 8 Gy) protocol and case 2 received a definitive (12 × 4 Gy) protocol. Complete remission was demonstrated on repeat CT scan five months after diagnosis in case 1 and seven months in case 2. Stable disease was documented on CT at four months for case 3; however, clinical signs in this dog remained controlled for 10 months in total. Case 1 died of unrelated causes five months after diagnosis, case 2 was euthanased due to the development of seizures 13 months after diagnosis, and case 3 was lost to follow-up 12 months after diagnosis. Melanoma should be considered as a rare differential diagnosis for primary nasal neoplasia in the dog and radiation therapy can be used as effective local therapy.     

Thyroid function tests in euthyroid dogs treated with L-thyroxine

The effects of treatment with L-thyroxine (1 mg/m2 of body surface/d, PO, for 8 weeks) on the thyroxine (T4) and triiodothyronine (T3) responses to thyrotropin (TSH) and thyrotropin-releasing hormone (TRH) administration were determined in 10 euthyroid Beagles; 4 other dogs acted as controls. The TSH response test was performed before treatment and at weeks 2, 4, and 8 of treatment in all dogs and at 2 and 4 weeks after cessation of treatment in 6 dogs. The TRH response test was performed before treatment and at week 6 of treatment in all dogs and at 5 weeks after cessation of treatment in 6 dogs. Suppression of the T3 response to TSH was evident at treatment week 2, whereas the T4 response was suppressed at week 4 and remained suppressed for the duration of the study. Four weeks after stopping treatment, T4 and T3 responses to TSH in 2 dogs were within the hypothyroid range. The T4 response to TRH was completely suppressed after 6 weeks of thyroxine treatment, but returned to pretreatment values by 5 weeks after cessation of treatment. Suppression of thyroid and pituitary function is evident after administration of a replacement dose of L-thyroxine to euthyroid dogs.     

Necrotizing enterotyphlocolitis in dogs treated with a potent antimuscarinic

To assess the safety of a potent muscarinic receptor antagonist (antimuscarinic) for human clinical testing, repeat-dose oral toxicity studies were conducted in the Beagle dog. Treatment resulted in unexpected gastrointestinal system effects that were likely mediated by the exaggerated pharmacologic effects of the antimuscarinic on intestinal motility. Dogs developed profound anorexia followed by severe bloody diarrhea, and at necropsy, the intestinal tract was distended, filled with red-tinged fluid, and the mucosa was reddened. Histologically, intestinal lesions consisted of severe epithelial necrosis and mucosal atrophy localized predominantly to the ileum and large intestine. Feces from dogs with diarrhea were culture-positive for Clostridium perfringens (CP), suggesting that CP might be the etiologic agent; however, the intestinal lesions were not consistent with histologic findings reported in dogs with hemorrhagic canine enteritis.     

Serum concentrations of cortisol and cortisone in healthy dogs and dogs with pituitary-dependent hyperadrenocorticism treated with trilostane

The serum concentrations of cortisol and cortisone were measured in 19 healthy dogs and in 13 dogs with pituitary-dependent hyperadrenocorticism (PDH) before and one hour after an injection of synthetic adrenocorticotropic hormone (ACTH). In the dogs with pdh, the cortisol and cortisone concentrations were measured before and after one to two weeks and three to seven weeks of treatment with trilostane. The dogs with PDH had significantly higher baseline and poststimulation concentrations of cortisol and cortisone, and higher baseline cortisol:cortisone ratios than the healthy dogs. During the treatment with trilostane, the poststimulation cortisol, the baseline and poststimulation cortisone concentrations, and the baseline and poststimulation cortisol:cortisone ratios decreased significantly. The decrease in poststimulation cortisone was significantly smaller than the decrease in cortisol.     

Transient enhancement of the serum antibody response to Brucella abortus strain 19 in cattle treated with levamisole

Two experiments were done on 57 steers. These cattle were allotted to 8 groups (4 groups/experiment) and vaccinated with 1 to 3 X 10(9) colony-forming units of Brucella abortus strain 19. Cattle in 3 of the 4 groups/experiment were given 6 mg of levamisole/kg, subcutaneously, either at the time of vaccination (day 0), 7 days later, or at both times. Serum antibody titers to B abortus were measured sequentially for 28 days in experiment 1 and for 56 days in experiment 2, using the card test, Rivanol test, complement-fixation test, fluorometric immunoassay, and an enzyme-linked immunosorbent assay. In general, the highest mean antibody titers, as determined by all serologic tests, occurred in steers treated with levamisole at 7 days after vaccination or in those treated at the time of vaccination and 7 days later. By the card test on day 56, there was a significantly (P less than 0.05) greater number of seropositive cattle among those given levamisole 7 days after seropositive cattle among those given strain 19 alone. Simultaneous administration of strain 19 and levamisole did not alter antibody responses to B abortus.     

Positive Coombs' test results in two dogs treated with amiodarone

Effects of amiodarone, an antiarrhythmic drug that is effective in suppressing severe ventricular arrhythmias that are refractory to other antiarrhythmic drugs, were evaluated in 2 dogs with cardiac disease. One dog was a Doberman Pinscher with cardiomyopathy that developed severe thrombocytopenia after receiving amiodarone for 7 months. The second was a Giant Schnauzer with acquired mitral valve degeneration that developed regenerative anemia after receiving amiodarone for 5 months. Results of direct Coombs' tests were positive in both dogs. Adverse effects of amiodarone are numerous; in dogs, the most common adverse effects are anorexia and hepatotoxicosis. Frequent CBC and serum biochemical analyses should be performed when amiodarone is administered with the intent of continuing the drug indefinitely.