MAGNETIC RESONANCE IMAGING OF THE BRAIN OF NORMAL NEONATAL FOALS

Magnetic resonance imaging (MRI) was performed on gthe brain of 5 normal, anesthetized, neonatal (age 3-to-6 days) Quarter Horse foals. The objectives of the study were to develop a technique for imaging the brain of neonatal foals, and to ascertain their normal brain anatomy. Interavenous propofol was administered for induction and maintenance of general anesthesia. Using spin echo MR techniques, T1 weighted sagittal and transverse views, and spin density and T2 weighted transverse views were successfully made of each foal. MR images provided excellent visualization of many anatomic struictures of the brain and head. MRI of the bgrain is feasible for selected neonantal equine patients.     

ADCC and complement-dependent lysis as immune mechanisms against EHV-1 infection in the horse

Immunity to equine herpesvirus type 1 (EHV-1) was evaluated using sera collected from yearling horses involved in a trial of a commercial vaccine. Measurement of the ability of these sera to mediate antibody-dependent cellular cytotoxicity and complement-dependent lysis revealed that these mechanisms, although potentially important in recovery from EHV-1 infection, do not play a role in protection following vaccination.     

Effect of acetylsalicylic acid on vascular damage and myointimal proliferation in canine pulmonary arteries subjected to chronic injury by Dirofilaria immitis

The effect of aspirin (ASA) on pulmonary artery response to chronic injury induced by Dirofilaria immitis was assessed in the dog. Eight dogs were studied for 30 days after adult heartworms were transplanted into the pulmonary arteries. Four dogs were treated with ASA (325 mg/day given orally) starting 3 days before the transplantation was done. Evan's blue dye was used to locate areas of vascular damage. Vascular morphology was assessed by scanning electron microscopy and light microscopy. According to results of the morphologic studies, nontreated dogs had extensive endothelial damage and significant adhesion of leukocytes and blood platelets. Blood vessels of ASA-treated dogs had less endothelial damage. Platelet adhesion on areas of vascular damage was less than that observed in nontreated dogs. Myointimal proliferative lesions were observed in both nontreated and ASA-treated dogs. However, the lesions in nontreated dogs were larger (means 68 +/- 7 mm2) and more complex than those in ASA-treated dogs (means 20 +/- 1 mm2). The results indicated that aspirin may protect against development of myointimal proliferation resulting from chronic vascular injury. The mechanism of the ASA protection may result from a combination of antiplatelet and anti-inflammatory effects, as well as a direct protective effect on vascular endothelium.     

The fungitoxicity of substituted 2-phenylbenzofurans

Thirty-seven 2-phenylbenzofurans, variously substituted in the homocyclic rings, were synthesised and assessed for antifungal activity in laboratory tests. High activity was shown only by compounds containing a hydroxy group, though amino compounds were also fungitoxic but at a lower level. Possible mechanisms by which these substitutions impart fungitoxicity are discussed with particular reference to the partitioning properties of the molecule.     

Clinical and laboratory findings in cats infected with feline immunodeficiency virus

Thirty-two cats referred to the Feline Studies Centre between June 1987 and October 1988, and 14 in-contact cats, were found to be infected with feline immunodeficiency virus. Most of the 46 cats were non-pedigree and free ranging; 27 were male (19 neutered) and 19 were female (18 neutered). Their ages ranged from one to 17 years and the average age was 5.8 years. The most common clinical signs were lethargy, inappetence, weight loss, pyrexia and lymphadenopathy; most cases had multiple abnormalities. Other common signs were gingivitis, diarrhoea, rhinitis and ocular discharge. Eight cats had neoplasia. The commonest haematological abnormalities were anaemia, neutropenia, lymphopenia and monocytosis. Eight cats had lymphocytosis; seven of these were in a single house-hold. Several cats had high serum globulin levels and half of those tested had high IgG levels. Seven cats had no detectable antibody to feline immunodeficiency virus even though the virus was cultured from the peripheral blood lymphocytes. During follow-up for up to 60 weeks one cat died and 23 were destroyed on humane grounds.     

An aspirin-prednisolone combination to modify postadulticide lung disease in heartworm-infected dogs

A combination of aspirin and prednisolone was used in an attempt to modify the pulmonary disease produced by thiacetarsamide treatment of heartworm-infected dogs. Results of 6 heartworm-infected dogs treated with prednisolone (1 mg/kg, daily for 4 weeks) and aspirin (10 mg/kg, daily for 4 weeks) after thiacetarsamide treatment were compared with previously published results of 3 groups of dogs (6 dogs/group). One of these 3 groups was a nontreated control group, another was treated with prednisolone, and the 3rd was treated with aspirin. All dogs, each with 9 adult heartworms transplanted, were treated with a 2-day, twice-a-day treatment of thiacetarsamide (1 mg/kg) 4 weeks after the transplant. Thoracic radiographs were taken before and at 1, 2, and 3 weeks after thiacetarsamide treatment to evaluate lung disease. Pulmonary arteriography was performed before and 3.5 weeks after thiacetarsamide treatment to evaluate pulmonary blood flow. After treatment, radiographs of the aspirin-prednisolone group were similar to radiographs of the prednisolone group, both with a marked attenuation of the parenchymal disease, as compared with the non-treated group. Addition of aspirin to prednisolone prevented the blood flow obstruction and intraluminal filling defects that were present in the groups not receiving aspirin. Sixteen of 54 transplanted heartworms survived thiacetarsamide treatment in both prednisolone-treated groups, in contrast to complete elimination of heartworms in the nontreated group. Aspirin may be considered for treatment of any heartworm-infected dog that does not have hemotypsis, but postthiacetarsamide use of prednisolone should be restricted to the dog that develops severe lung disease after the heartworms have been killed.     

Cellular content of secretions obtained by lavage from different levels of the equine respiratory tract

Lavage procedures were used to obtain samples of respiratory secretions from the nasal cavity, trachea, bronchi and bronchoalveolar level of apparently normal conscious horses, and the cellular composition of the lavage fluids was assessed. There was a progressive increase in total cell count of the secretions obtained from the upper to the lower respiratory tracts. Nasal lavage fluid was composed chiefly of epithelial cells, whereas tracheal, bronchial and bronchoalveolar fluids contained higher proportions of macrophages, lymphocytes and neutrophils. Eosinophils and mast cells were identified in small numbers. The results of the differential cell counts were compared with previous published reports, which revealed some major differences between studies. It is suggested that these differences may relate to variations in the collection technique, the cytological interpretation of cell types, the presence of subclinical airway disease, and the degree of exposure to airborne environmental contaminants.