Efficacy of ivermectin against Dirofilaria immitis larvae in dogs 30 and 45 days after induced infection

Forty-two Beagles, 14 to 15 weeks of age, were injected subcutaneously with 50 infective larvae of Dirofilaria immitis and were allotted by weight, within sex, to 6 treatment groups. Group 1 served as nonmedicated vehicle-treated controls; groups 2 through 5 were given an oral tablet form of ivermectin at dosages of 0.3 micrograms/kg, 1.0 micrograms/kg, 2.0 micrograms/kg, and 3.3 micrograms/kg at 30 days after inoculation; group 6 was given the 2.0 micrograms/kg dosage at 45 days after inoculation. Dogs were euthanatized and necropsied 154 days after treatment (day 139 for dogs in group 6) and examined for heartworms. On the numerical bases of helminths recovered in the groups, the efficacies for preventing heartworm maturation were 0% (group 2), 53.2% (group 3), 97.2% (group 4), 98.1% (group 5), and 63.8% (group 6). Drug-related adverse reactions were not detected.     

Procainamide in the dog: antiarrhythmic plasma concentrations after intravenous administration

Procainamide hydrochloride was administered to ouabain-intoxicated dogs to determine an antiarrhythmic plasma concentration of procainamide. Ventricular arrhythmias were produced in dogs following intravenous injections of ouabain. After a sustained ventricular tachycardia was achieved, procainamide was administered and plasma samples collected for assay. Plasma procainamide was assayed by fluorescence polarization immunoassay. Procainamide was administered at increasingly higher constant rate infusions in order to achieve intermittent, steady-state plasma concentrations. Infusion rates were calculated on the basis of previous pharmacokinetic information. All six dogs that received procainamide converted to a normal sinus cardiac rhythm after attaining a mean plasma concentration of 33.8 micrograms/ml with a range of 48.5 micrograms/ml-25.0 micrograms/ml. It was observed that the computer-generated prediction of plasma concentrations based upon previous pharmacokinetic data produced an underestimate of the actual plasma concentrations. These data may suggest that plasma concentrations of procainamide for controlling some cardiac arrhythmias in dogs may be higher than plasma concentrations cited for human patients.     

Use of sodium hydroxide treated selenium deficient barley to induce vitamin E and selenium deficiency in yearling cattle

Selenium deficient barley grown in Northern Ireland was treated with sodium hydroxide to deplete it of vitamin E. Housed cattle fed a complete diet based on this treated barley developed nutritional degenerative myopathy, showing that spontaneous myopathy in yearling cattle can be the result of vitamin E and selenium deficiency alone. The diet used is as effective and cheaper than others presently in use for inducing degenerative myopathy.     

Prevalence of Mycoplasma gallisepticum and M. synoviae in commercial layers in southern and central California

The prevalence of Mycoplasma gallisepticum (MG) and M. synoviae (MS) in commercial pullet and layer flocks in Southern and Central California was estimated by testing serum and egg-yolk samples from 360 sample flocks in Southern California and 41 sample flocks in Central California. Data relating to potential risk factors associated with MG and MS infections were collected. The estimated true prevalence rate of MG was 73% in Southern California and 3% in Central California. The estimated true prevalence rate of MS was 91% in Southern California and 32% in Central California. Compared with uninfected flocks, MG-infected flocks in Southern California were significantly older and were medicated less (P less than 0.05). More managements were under a multiple-age system, more flocks had molted, more were vaccinated with F-strain, and more had concurrent infection with MS (P less than 0.05). Only one sample flock in Central California was MG-infected; none were vaccinated with F-strain. In Southern California, MS-infected flocks were older than uninfected flocks, more had molted, more were medicated, and more had concurrent infection with MG (P less than 0.05). In Central California, MS-infected flocks did not differ significantly from uninfected flocks in any factor examined; the lack of statistical significance may be due to small sample size.     

Cellular morphology of Clostridium spiroforme

The helically-coiled bacterium, Clostridium spiroforme, has been shown to consist of an ordered aggregation of numerous individual semi-circular cells joined end to end.     

Responses of atopic dogs to regional allergens: 268 cases (1981-1984)

Responses of atopic dogs to intradermal challenge with 60 allergens were determined and compared for 4 regions of the United States Twenty-seven allergens incited significantly higher responses in atopic dogs residing in northern Florida, when compared with dogs in Illinois; responses to 28 allergens were more significant in dogs residing in southern Florida vs Illinois. Only 1 allergen caused more responses in atopic dogs in northern Florida, compared with dogs in southern Florida. Females had a higher tendency to develop clinical signs of atopy. Dogs of the West Highland White Terrier, Cairn Terrier, English Setter, Irish Setter, Dalmatian, Lhasa Apso, Golden Retriever, and Labrador Retriever breeds were found to be predisposed to develop clinical signs of atopy. Dogs of the Poodle, Pug, German Shepherd Dog, Cocker Spaniel, Bulldog, Schnauzer, Doberman Pinscher breeds, of mixed breeding, and of terrier breeds other than the 2 aforementioned were not found to have a higher prevalence, when compared with the general hospital population. Of the atopic dogs evaluated in Florida, 79% had a significant response to flea antigen, compared with only 9% of atopic dogs evaluated in Illinois.     

A COMPARISON OF MANUAL AND AUTOMATIC ULTRASOUND-GUIDED BIOPSY TECHNIQUES

A manual, ultrasound-guided biopsy technique was compared to a new automatic method using a new biopsy device. The liver and the left kidney of 10 dogs were biopsied using the two methods. The specimens from the biopsies were compared for size and quality. Results demonstrate that larger and higher quality samples were obtained with the new automatic method.     

Nitrogenous constituents in plasma of foals weaned at three, four or six months of age

A study was conducted to measure the nitrogenous constituents in the blood of foals weaned at 3, 4 or 6 months of age (four foals per weaning age).Jugular blood was sampled from one week prior to weaning until one month post-weaning, and was analyzed for total protein, albumin, creatinine, urea Nitrogen and free amino acid content. Results indicated that the concentrations of most of the constituents in the blood of foals were not altered by the age of weaning, however, free amino acids decreased as age at weaning increased and creatinine was significantly higher in foals weaned at 6 months of age. Plasma creatinine, lysine and methionine levels generally decreased between pre-weaning and one month post-weaning. These data establish baseline values for blood nitrogenous constituents in foals at weaning.     

Morphologic studies of uveoscleral outflow in normotensive and glaucomatous beagles with fluorescein-labeled dextran

Aqueous humor leaves the anterior chamber through 2 pathways: the trabecular meshwork of the iridocorneal angle and the unconventional uveoscleral route. In the latter route, aqueous humor leaves the anterior chamber, passes caudally through the trabecular meshwork and sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is absorbed by the choroidal and scleral circulation. Fluorescein-labeled dextran was slowly infused into the posterior chamber of healthy and glaucomatous Beagles for 30 minutes. The eyes were fixed in a mixture of 70% alcohol and formalin, placed in epoxy resin for histologic evaluation, and examined by fluorescent microscopy. Fluorescence was detected in the healthy dogs throughout the uveoscleral pathway. In the glaucomatous dogs, the uveoscleral outflow was decreased or completely absent.