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Disassociation of bactericidal and fungistatic activities from the oxidative burst of avian macrophages
1990
Harmon, B.G. | Glisson, J.R.
Avian peritoneal exudate macrophages, when exposed to phagocytic stimuli, produced an appreciable oxidative burst as measured by production of chemiluminescence, superoxide anion, and hydrogen peroxide. Metabolic inhibitors of the oxidative burst and scavengers of oxygen radicals clearly inhibited macrophage chemiluminescence, but had no significant effect on macrophage bactericidal activity against Escherichia coli or fungistatic activity against Candida tropicalis. Therefore, avian macrophages were capable of oxygen-independent bactericidal and fungistatic activities.
Mostrar más [+] Menos [-]Influence of preinduction methoxamine, lactated Ringer solution, or hypertonic saline solution infusion or postinduction dobutamine infusion on anesthetic-induced hypotension in horses
1990
Dyson, D.H. | Pascoe, P.J.
A controlled study of the cardiovascular responses in horses anesthetized with acepromazine (0.05 mg/kg of body weight, IV), guaifenesin (100 mg/kg, IV), thiamylal (5.0 mg/kg, IV), and halothane in O2 (1.2 to 1.4% end-expired concentration) was performed to determine whether hypotension could be prevented by use of various treatments. Six horses were given 5 treatments in a randomized sequence: no treatment (control), methoxamine (0.04 mg/kg IV), lactated Ringer solution (20.0 ml/kg, IV), 7.5% hypertonic saline solution (4.0 ml/kg, IV), or constant infusion of dobutamine (5.0 mg/kg/min, IV) during anesthesia. Heart rate, ECG, blood pressure, central venous pressure, cardiac output, blood gas analysis, PCV, and plasma total protein concentration were measured during the study. Compared with the control value, an increase in blood pressure during halothane administration was observed after administration of lactated Ringer solution, hypertonic saline solution, or dobutamine (P < 0.05). The improved blood pressure response to hypertonic saline solution and dobutamine was related to an increase in cardiac output, which was statistically significant (P < 0.05) Other statistically significant differences in cardiopulmonary responses among treatments were not observed during anesthesia. The PCV was increased in response to dobutamine infusion, and plasma total protein concentration was reduced in response to administration of hypertonic saline or lactated Ringer solution.
Mostrar más [+] Menos [-]Clinical and biochemical alterations in calves with nutritionally induced polioencephalomalacia
1990
Sager, R.L. | Hamar, D.W. | Gould, D.H.
Polioencephalomalacia (PEM) was induced in calves by feeding a semipurified, low-roughage diet of variable copper and molybdenum composition. Two formulations resulting in Cu-insufficient and Cu-sufficient forms of the diet were fed (n = 10 and 4 calves, respectively); both diets induced PEM. Clinical signs of disease developed as early as 15 days after transition to the experimental diets and included impaired vision, decreased response to external stimuli, and abnormal gait. Grossly evident cerebrocortical lesions consisted of laminar areas of cavitation and/or autofluorescence seen under UV illumination. Hepatic Cu concentration was decreased in calves fed the Cu-insufficient diet, but not below normal range. During the course of feeding either diet, rumen pH decreased, rumen volatile fatty acid concentrations increased, rumen and blood lactic acid concentrations increased, and rumen and plasma thiamine concentrations increased. The thiamine pyrophosphate effect on erythrocyte transketolase activitywas unaltered in calves of either diet group. This nutritionally induced form of PEM does not appear to be related to Cu deficiency or reduction in plasmaor rumen thiamine concentration.
Mostrar más [+] Menos [-]Hypermetabolic priming of canine neutrophils by 7-S nerve growth factor
1990
Gruber, D.F. | O'Halloran, K.P. | D'Alesandro, M.M. | Farese, A.M.
Canine circulating neutrophils, isolated by a blood lysing technique, were incubated with 7-S nerve growth factor (NGF), at final concentrations between 12.5 and 800 ng/ml, for 30 minutes at 37 C. Neutrophil cytosolic H2O2 production, measured by flow cytometry, after 7-S NGF incubation was not significantly different from that produced at 37 C (baseline temperature controls) alone. Phorbol myristate acetate (PMA; 100 ng/ml) stimulation of neutrophils produced cytosolic H2O2 concentrations almost 13 times that of baseline temperature control neutrophils. Preincubation of neutrophils with 7-S NGF (100 to 800 ng/ml, 30 minutes, 37 C) and subsequent stimulation by PMA resulted in augmented H2O2 production in excess of twice that of neutrophils treated with PMA alone, and almost 30 times that of baseline temperature controls.
Mostrar más [+] Menos [-]Anatomy of the orbital fasciae and the third eyelid in dogs
1990
Constantinescu, G.M. | McClure, R.C.
The connective tissue structures commonly referred to as the periorbita, orbital septum, muscular fasciae, and vagina bulbi or collectively, as the orbital fasciae were dissected then illustrated and described. Two sheets (layers) of the periorbita (endorbita) were found in our dogs. The periorbita should be renamed endorbita because of its anatomic relations. The periorbita did not always fuse with the periosteum of frontal and sphenoid bones. Rather, the periorbita and the periosteum were often distinct and separate; only medioventrally did several fibrous bands unite the superficial sheet of the endorbita with the periosteum. Two layers of the endorbita fused with the periosteum of the margin of the bony orbit and with the orbital ligament. The muscular fasciae were divided into 3 layers. The superficial layer extended caudally from the orbital septum, was thick, and was pierced by arteries, veins, and nerves. The middle layer was attached to the sclerocorneal junction and, at the temporal canthus of the eye, was divided into superficial and deep sheets. The deep portion was attached to the lateral angle of the third eyelid, similar to a strong ligament. The deep layer of the muscular fasciae extended caudally from the sclerocorneal junction in intimate contact with recti and oblique muscles of the eyeball. The deep portion of the deep muscular fascia covered the deep surface of all recti muscles and separated them from the retractor bulbi muscle. Intermuscular septa were observed between middle and deep muscular fascia layers. The body of the third eyelid was located between superficial and middle muscular fascia layers and was fixed ventrally to the lateral angle of the eye by the deep sheet of the middle muscular fascia.
Mostrar más [+] Menos [-]Effects of flunixin and flunixin plus prednisone on the gastrointestinal tract of dogs
1990
Dow, S.W. | Rosychuk, R.A.W. | McChesney, A.E. | Curtis, C.R.
Flunixin meglumine has been reported to induce gastrointestinal lesions in dogs when administered at therapeutic dosages. We administered flunixin meglumine to dogs daily for 10 days to assess the effect of this drug on the gastrointestinal tract. We also evaluated the possibility of corticosteroid potentiation of gastrointestinal toxicosis by concurrent administration of prednisone to 1 group of dogs. Dogs were monitored for gastrointestinal toxicosis by means of serial endoscopic evaluation, measurement of fecal occult blood, PCV, and total solid concentration, and by physical examination. There were 3 treatment groups of 5 dogs each. Group-1 dogs were given 2.2 mg of flunixin meglumine/kg daily, in 2 divided doses IM; group-2 dogs were given 4.4 mg of flunixin meglumine/kg daily, in 2 divided doses IM; and group-3 dogs were given 2.2 mg of flunixin meglumine/kg daily, in 2 divided doses IM plus 1.1 mg of prednisone/kg/d orally, in 2 divided doses. A fourth group of 5 dogs served as a control group. Endoscopically visible gastric mucosal lesions developed in all treated dogs within 4 days of initiating treatment. Lesions first developed in the gastric pylorus and antrum and lesions at these sites were more severe than those observed elsewhere. Dogs treated with flunixin meglumine plus prednisone developed the earliest and most severe lesions; lesion scores in group-2 dogs were higher than those in group-1 dogs. All dogs treated had occult blood in their feces by day 5 and its presence appeared to correlate more closely with endoscopic findings than did physical examination findings or changes in values for PCV or total solids. Deep ulcers were observed in the pylorus of most treated dogs examined at necropsy on day 10. Shallow ulcers and erosions were in the small intestine of group-2 and -3 dogs. Capillary microthrombi, associated with lesions of coagulative necrosis of superficial epithelium, were found in the colonic and small intestinal mucosa of several dogs in groups 2 and 3, and were suggestive of vascular injury. From results of this study, it was concluded that flunixin meglumine, administered at therapeutic doses, induced early gastric mucosal injury in dogs and that concurrent administration of prednisone may have exacerbated the gastrointestinal injury induced by flunixin alone. Endoscopic evaluation and measurement of fecal occult blood appeared to be more sensitive than other methods evaluated for detection of gastrointestinal injury.
Mostrar más [+] Menos [-]Methods for detection of immune-mediated neutropenia in horses, using antineutrophil serum of rabbit origin
1990
Jain, N.C. | Vegad, J.L. | Kono, C.S.
Equine neutrophil antibody was raised in rabbits inoculated with equine neutrophils isolated to purity > 99.0%, using Percoll density-gradient sedimentation. Neutrophil antibody was detected by use of agar gel diffusion, leukoagglutination, indirect immunofluorescence, staphylococcal protein A and streptococcal protein G binding, and phagocytic inhibition techniques. Precipitin lines and leukoagglutination were seen in antiserum dilutions of 1:4 and 1:64, respectively. The specific nature of leukoagglutination was characterized by the formation of rosette-like clumps of neutrophils. Specific bright membranous fluorescence was seen in neutrophils treated with the antiserum and exposed to fluorescein-conjugated goat anti-rabbit immunoglobulin, and staphylococcal protein A and streptococcal protein G. Whereas the indirect immunofluorescence and protein G-binding tests were equally sensitive and resulted in titer of 1:256, the protein A-binding test was less sensitive and resulted in titer of only 1:32. Nonspecific binding of protein A and protein G was noticed as uniform or patchy cellular fluorescence in a small number of neutrophils. Treatment of neutrophils with antiserum up to dilution of 1:8 resulted in a significant (P < 0.05) suppression of phagocytosis of opsonized zymosan particles. Thus, protein G-binding and indirect immunofluorescence tests are highly sensitive to detect neutrophil antibody and may be used to diagnose immune-mediated neutropenias in horses and, possibly, in other animal species.
Mostrar más [+] Menos [-]Excretion of porcine parvovirus through the genital tract of boars
1990
Gradil, C. | Molitor, T. | Harding, M. | Crabo, B.
The putative binding of porcine parvovirus (PPV) to semen components in vitro was examined along with the shedding pattern of PPV in oronasally infected boars. Porcine parvovirus DNA was determined to be bound to spermatozoa that had been incubated in vitro with PPV and washed to remove loosely adherent virus. To determine whether PPV was shed in the semen, four 8-month-old boars, seronegative for PPV, were inoculated oronasally with a virulent strain of PPV. Prior to virus inoculation, a catheter was surgically implanted in the vas deferens for the purpose of collecting cauda epididymal semen free of extrinsic contamination. Epididymal semen specimens were collected prior to inoculation and daily thereafter for 21 days. A fifth boar was inoculated oronasally with PPV, but semen was collected by electroejaculation twice weekly for an equal period of time. Reproductive glands and semen specimens from all boars were examined by nucleic acid hybridization for the presence of viral DNA. All boars seroconverted to PPV, as evidenced by serum antibody titers ranging from 512 to 8,192 hemagglutinating inhibition units/50 microliter. Porcine parvovirus DNA was detected in epididymal semen of 3 of 4 catheterized boars on postinoculation days 5 through 9, but not in semen obtained by electroejaculation. Viral DNA was consistently detected in tissue samples collected on postinoculation days 8 and 21 from the scrotal lymph nodes (4 of 5 boars) and epididymides (3 of 5 boars).
Mostrar más [+] Menos [-]Bacteriologic and pathologic studies of hepatic lesions in sheep
1990
Scanlan, C.M. | Edwards, J.F.
At an abattoir, lesion specimens from 140 condemned sheep livers were collected for bacteriologic culture and for pathologic examination. Grossly, 23 lesions were abscesses; from 9 of which, Fusobacterium necrophorum biovar A (3 in pure culture and 6 in mixed culture) was isolated and from 14 of which, biovar B (6 in pure culture and 8 in mixed culture) was isolated. Escherichia coli was the predominant facultative anaerobic bacterium and Clostridium perfringens was the predominant obligate anaerobic bacterium isolated from the 14 lesions with mixed bacterial infection. Histologically, these lesions had a core of coagulation necrosis, encircled by a zone of necrotic phagocytic cells and bacteria with cellular characteristics of F necrophorum biovars A or B, and a connective tissue capsule. Of the 117 lesions without F necrophorum, 49 were culture-positive (for other organisms) and 69 were culture-negative. These 117 lesions were fibrous and were smaller than the 23 abscesses. A variety of gram-positive and gram-negative facultative anaerobic and obligate anaerobic bacteria was isolated from the culture-positive lesions, but always in low numbers. Eleven culture-negative and 18 culture-positive lesions were examined and had histologic characteristics of parasite-induced granulomas, with numerous eosinophils and epithelioid giant cells. Results of the study indicated that the histologic appearance of ovine hepatic lesions with F necrophorum was similar to bovine liver abscesses caused by F necrophorum, but unlike bovine liver abscesses, F necrophorum biovar B was isolated more frequently than was biovar A and often in pure culture. Most of the lesions in the condemned livers were parasite-induced granulomas.
Mostrar más [+] Menos [-]Cardiovascular changes after bone marrow transplantation in dogs with mucopolysaccharidosis I
1990
Gompf, R.E. | Shull, R.M. | Breider, M.A. | Scott, J.A. | Constantopoulos, G.C.
Five dogs with mucopolysaccharidosis I, 3 of which had been treated with bone marrow transplantation (BMT), were evaluated for 20 months with electrocardiography, thoracic radiography, and M-mode and 2-dimensional echocardiography. Treated and untreated (control) dogs had widened P waves on ECG. Thoracic radiographs remained normal for all dogs throughout the study. Thickening of the mitral valve was observed on echocardiograms of dogs in both groups, but the untreated dogs appeared to have thicker valves. Concentrations of glycosaminoglycans in the mitral valves and myocardium were higher in control dogs than in treated dogs. Markedly large aortic root diameters were observed on echocardiograms in both untreated dogs, but aortic root diameters remained normal in treated dogs. Echocardiography, but notelectrocardiography, was useful in monitoring heart enlargement in each dog. Dogs treated with BMT generally had less-severe cardiac changes and slower disease progression than control dogs.
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