Visceral neosporosis in a 10-year-old horse.
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Animals↗
Biomedical subjects
B G Harmon
Publications and source records attributed to B G Harmon.
Antimicrobial activity of chicken and turkey heterophil peptides CHP1, CHP2, THP1, and THP3.
Four avian heterophil antimicrobial cationic peptides (Chicken Heterophil Peptides 1 and 2, and Turkey Heterophil Peptides 1 and 3) were evaluated for in vitro microbicidal activity against selected avian pathogens and human pathogens which are harbored by birds. At concentrations of 16-2 micrograms/ml, all four avian peptides effected a greater than 90% reduction in the survival of Candida albicans, Salmonella enteriditis, and Campylobacter jejuni. None of the peptides, including the known antimicrobial peptide protamine (used as a positive control), were able to reduce the survival of Pasteurella multocida by 90% at the maximum peptide concentration (16 micrograms/ml) tested. At 16 micrograms/ml, the turkey peptide THP3 did not effect a 90% reduction in survival of Bordetella avium, Escherichia coli, or Salmonella typhimurium, while all of the other peptides tested were effective at this concentration or less. This peptide, THP3, does not share the same homologous amino acid sequence shared by the other three peptides. Under our experimental conditions, none of the peptides neutralized Infectious Bronchitis Virus, an enveloped coronavirus of chickens.
Animals↗
Isolation of antimicrobial peptides from avian heterophils.
Five bactericidal peptides (chicken heterophil peptides CHP1 and CHP2; turkey heterophil peptides THP1, THP2, and THP3) were purified from avian heterophil granules. All peptides were cationic and rich in cysteine, arginine, and lysine. The complete amino acid sequence, consisting of 39 amino acids, was determined for CHP1. This peptide had a molecular weight of 4481 as determined by mass spectrometry. Partial NH2-terminal amino acid sequences were obtained for the remaining peptides. Both chicken peptides and THP1 shared sequence homology at 22 residues and a cysteine motif which was similar to that of bovine beta-defensins. THP2 and THP3 were homologous to each other but were not homologous to the other three and had a unique cysteine motif. Peptides CHP1, CHP2, and THP1 killed Staphylococcus aureus and Escherichia coli in vitro, whereas THP2 and THP3 killed only S. aureus in vitro.
Amino Acid Sequence↗
Large granular lymphocyte neoplasia in an aged mare.
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Animals↗
Pulmonary lesions in mice inoculated with Actinobacillus pleuropneumoniae hemolysin and lipopolysaccharide.
Non-Swiss albino (CF1) male mice were used as a model to study the effects of specific toxic components of Actinobacillus pleuropneumoniae on the respiratory system. Mice were divided into five groups of ten each and were inoculated by the intranasal route with whole-cell Actinobacillus pleuropneumoniae serotype 1, cell-free culture supernatant fluid (CFCSF) containing hemolysin protein, purified lipopolysaccharide (LPS), heat-treated CFCSF, or phosphate-buffered saline solution. Pulmonary lesions were evaluated at 6 and 12 hours after inoculation. Mice inoculated with whole cells, CFCSF, and LPS developed severe purulent bronchiolitis and alveolitis. Focal pulmonary necrosis was also observed in these three groups but was most consistent in the CFCSF-inoculated mice. Ultrastructurally, lungs from mice inoculated with whole cells, LPS, and CFCSF were characterized by severe degenerative changes in type I and type II pneumocytes. Alveolar spaces contained cellular debris and fibrin. Endothelial cells were swollen, and selected pulmonary capillaries were occluded with platelets and fibrin. Infiltrating neutrophils were often swollen, vacuolated, and degranulated. Although inoculation with relatively large numbers of A. pleuropneumoniae are required to kill mice, the mouse lung appears quite sensitive to the toxic components produced by these bacteria. The elaboration of these two toxic components by A. pleuropneumoniae may be responsible for the characteristic pulmonary inflammatory and necrotic lesions observed in infected swine.
Actinobacillus Infections↗
Avian keratoacanthoma (dermal squamous cell carcinoma) in broiler chicken carcasses.
Multiple lesions of dermal squamous cell carcinoma are found at a low frequency (0.04%) in the carcasses of young meat-type chickens at slaughter. For this study, affected carcasses (n = 308) were removed from the processing line, and lesions were characterized by size, distribution, and morphology. Carcasses were also sexed and examined for evidence of metastasis. Nodular (n = 297) and ulcerative (n = 1,707) lesions were counted and examined. Most lesions were present in the pectoral, dorsopelvic, and femoral feather tracts. Few lesions (n = 11) were found in wing tracts. Mean diameter was 5.4 mm for ulcerative lesions and 3.1 mm for nodular lesions. Histologic sections of ulcerative (n = 579) and nodular (n = 113) lesions were examined. Small nodular lesions originated from hyperplastic feather follicle epithelium. Nodules contained keratin-filled cysts lined by squamous epithelium that were associated with isolated islands and infiltrating cords of dermal keratinocytes. Loss of surface epithelium resulted in noduloulcerative and ulcerative lesions. Invasion of underlying skeletal muscle and evidence of visceral metastasis were not present, but invasion through elastic laminae and into the subcutis was present in 20.5% (134/654) of the lesions examined. The nodular lesions in these carcasses were morphologically similar to early nodular lesions previously described in live chickens as avian keratoacanthomas. A retrospective study compared selected production parameters and disease condemnations to the prevalence of squamous cell carcinoma in 665 flocks of broiler chickens. There was a positive correlation (P < 0.0001) with the occurrence of airsacculitis but a negative correlation with increased age and condemnations for leukosis (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Hydatid disease in a horse.
During routine necropsy of a 28-year-old horse with intestinal volvulus, numerous hydatid cysts were discovered in the liver. Viable protoscolices of Echinococcus granulosus were obtained from the cyst. As a 4-year-old, this horse had been imported from an area that is enzootic for equine hydatidosis.
Animals↗
Protective efficacy of conjugate vaccines against experimental challenge with porcine Actinobacillus pleuropneumoniae.
In an attempt to protect pigs against swine pleuropneumonia induced by Actinobacillus pleuropneumoniae (SPAP) by neutralizing the effects of three virulence factors of A. pleuropneumoniae--the capsular polysaccharide (CP), the lipopolysaccharide (LPS), and the hemolysin protein (HP)--two subunit conjugate vaccines were prepared by covalently coupling the CP to the HP and the LPS to the HP. The CP, LPS, and HP were isolated from A. pleuropneumoniae, strain 4074, serotype 1, and the protective efficacy of the conjugate vaccines in swine experimentally infected with A. pleuropneumoniae was evaluated. Following a booster vaccination, a significant (P < 0.05) IgG antibody response to the CP, LPS, and HP was detected in the vaccinated pigs. The pigs vaccinated with the CP-HP and LPS-HP conjugates exhibited significantly less mortality (P < 0.05) and significantly greater weight gain (P < 0.001) than unvaccinated pigs. Vaccinated pigs exhibited significantly fewer and less extensive gross pulmonary lesions (P < 0.001) when compared with unvaccinated pigs. Thus, on the basis of mortality, weight gains, and pulmonary lesion formation, the two conjugate vaccines used in conjunction with one another provide noticeable protective efficacy against SPAP.
Actinobacillus Infections↗
Basic science and applied science instruction: are they compatible?
Basic science and applied science instruction are compatible and essential for animal science professionals to succeed in their chosen career. Application of science is a continuum. Although production methods are constantly evolving, the science on which changes are made is fixed and fundamental. Only our understanding changes. We are educating students in preparation for a life-long learning process. Viability of animal science departments depends on attracting and challenging students with curricula that are demanding, create curiosity, and prepare students to understand the "whys and hows" of the phenomena of animal biology.
Animal Husbandry↗
Hematuria and weight loss in a mare with pancreatic adenocarcinoma.
This clinical report describes an 11-yr-old Thoroughbred mare that presented with clinical signs of weight loss and hematuria. History and clinical findings suggested the mare had neoplasia of the urogenital system. Although ultrasound-guided biopsy of the perirenal mass did not yield abnormal cells, large irregular cells were isolated from the thoracic and peritoneal fluid. At necropsy, multiple firm nodules were disseminated throughout the peritoneal cavity. Histological examination of the nodules revealed cells that were consistent with a pancreatic exocrine adenocarcinoma. This is the first report of pancreatic adenocarcinoma causing dysfunction of the urogenital system.
Adenocarcinoma↗
Heterophil function in healthy chickens and in chickens with experimentally induced staphylococcal tenosynovitis.
Heterophil function was evaluated in 16 healthy chickens and in 46 chickens with experimentally induced staphylococcal tenosynovitis. In paired blood samples, heterophils from chickens with tenosynovitis had a significant increase in adherence, chemotaxis, phagocytosis, and bacterial killing of Staphylococcus aureus compared to heterophils from healthy chickens. The percent adherence of heterophils to nylon fiber columns increased significantly from a 78.4% mean +/- 6.6% standard deviation to 87.6% +/- 3.2% after induction of staphylococcal tenosynovitis. Heterophil movement following in vitro exposure to saline or endotoxin was increased in chickens with tenosynovitis; 3 +/- 1 heterophils/0.25 mm2 to 10 +/- 6 heterophils/0.25 mm2 and 136 +/- 29 heterophils/0.25 mm2 to 340 +/- 74 heterophils/0.25 mm2, respectively. Endotoxin-activated serum was chemoattractive for heterophils from all chickens. Flow cytometry was used to define the heterophil population on light scatter histograms, evaluate individual cell phagocytosis of latex beads, and quantitate the number of beads phagocytosed per heterophil. When incubated with increased numbers of beads, only heterophils from chickens with tenosynovitis phagocytosed higher numbers of beads. At heterophil to bead ratios of 1:10, the percentage of heterophils that phagocytosed beads increased from baseline values of 37.8% +/- 9.0% to post-infection values of 67.3% +/- 7.5%. Using 1:20 heterophil to bead ratios, heterophil phagocytosis increased from 38.7% +/- 9.9% to post-infection values of 79.8% +/- 7.3%. Heterophils from all chickens were able to phagocytose and kill log phase staphylococcal bacteria. After phagocytosis, the heterophils from chickens with staphylococcal tenosynovitis rapidly decreased the number of viable bacterial colony forming-units per milliliter by approximately one log.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Resistance of Pasteurella multocida A:3,4 to phagocytosis by turkey macrophages and heterophils.
A virulent field isolate and 2 vaccine strains of Pasteurella multocida A:3,4 were compared for resistance to phagocytosis by turkey macrophages and heterophils, using in vitro assays. The least virulent vaccine strain (M-9) was phagocytosed to a greater degree than was the field isolate or the other vaccine strain (Clemson University). All 3 bacteria differed significantly from each other in the amount of capsular material present as measured by polycationic ferritin labeling and electron microscopy. Removal of the capsule with hyaluronidase resulted in a significant increase in phagocytosis of the field isolate.
Animals↗
Septicemia in vaccinated and nonvaccinated turkeys inoculated with Pasteurella multocida serotype A:3,4.
Sixty-four, 10-week-old turkeys were inoculated with a highly virulent field isolate (86-1913) of Pasteurella multocida serotype A:3,4 by an oculo-nasal-oral route. Inoculated turkeys were examined at 4, 8, 16, 20, and 24 hours post-inoculation for bacteremia and histologic lesions. Bacteremia was detected in one of six turkeys 8 hours after inoculation and in four of six turkey poults at 16 hours post-inoculation. Pasteurella multocida was isolated from the spleens of two turkeys at 8 hours and from the spleens of all six poults 16 hours after inoculation. Peak concentrations of P. multocida reached 10(9) colony forming units per ml of blood. At 4 to 8 hours post-inoculation, isolate 86-1913 produced a fibrinopurulent bronchopneumonia followed by severe pulmonary necrosis, pleuritis, vasculitis; and, at 16 to 24 hours post-inoculation numerous extracellular bacteria were observed. Hepatic lesions included focal heterophil aggregates 8 hours after inoculation; these progressed to hepatic necrosis. Numerous extracellular bacteria within sinusoids were present 16 to 24 hours after inoculation. At 16 to 24 hours post-inoculation, there was degeneration of periarteriolar reticular cells in the spleen; these cells progressed to coalescing coagulative splenic necrosis with extracellular bacterial colonies. A second group of 41, 10-week-old turkeys, previously vaccinated with the Clemson University strain of P. multocida serotype A:3,4, were challenged with isolate 86-1913.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Disassociation of bactericidal and fungistatic activities from the oxidative burst of avian macrophages.
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.
Animals↗
Macrophage function in mammary glands of Brucella abortus-infected cows and cows that resisted infection after inoculation of Brucella abortus.
Nonvaccinated pregnant cows were segregated retrospectively into 2 groups following inoculation with Brucella abortus strain 2308. One group resisted infection (resistant cows) and the other group developed active infections (susceptible cows) and subsequently aborted. Mammary gland macrophages collected from the 2 groups of cows were compared, using in vitro functional assays. In a chemiluminescence assay, mammary gland macrophages from resistant cows produced significantly (P = 0.014) higher oxidative burst activity than did macrophages from susceptible cows. Macrophages from resistant cows had significantly (P = 0.038) greater bacteriostatic activity against B abortus than did macrophages from susceptible cows. Differences in lysosomal enzymatic activity or Fc receptor expression were not observed for macrophages from the 2 groups of cows. Differences in macrophage function may be one factor responsible for natural resistance to Brucella infection in cattle.
Abortion, Veterinary↗
Evaluation of the opsonic capacity of core lipopolysaccharide antiserum of equine origin against smooth Escherichia coli 0111:B4, using macrophage chemiluminescence.
A study was performed to determine whether equine antiserum to core lipopolysaccharide (LPS) would enhance phagocytosis of smooth gram-negative (GN) organisms by equine macrophages. Five healthy adult horses (group A) were immunized with a bacterin prepared from the J-5 mutant of Escherichia coli 0111:B4 and Salmonella minnesota R595 to produce antibodies to core LPS. Five horses (group B) served as nonimmunized controls and were given physiologic saline solution instead of the rough mutant bacterin. Serum antibody titers to core LPS and to smooth E coli 0111:B4 were determined by indirect ELISA. Four serum pools were prepared: pool 1 = sera from horses in group B prior to immunization; pool 2 = sera from horses in group A prior to immunization (preimmune serum); pool 3 = sera from horses in group B, 7 days after the last saline injection; pool 4 = sera from horses in group A, 7 days after the last immunization (core LPS antiserum). The serum pools, either unheated or heated 30 minutes at 56 C, in 3 dilutions (1/50, 1/100, 1/500) were used to opsonize smooth E coli 0111:B4 in an assay of equine peritoneal macrophage chemiluminescence (CL). Peritoneal fluid was collected from clinically normal horses and the macrophages were purified by adherence to borosilicate glass scintillation vials. Each serum type and dilution was added to triplicate vials containing 10(7) colony-forming units of E coli 0111:B4. Luminol-dependent CL was measured with a liquid scintillation counter in the out-of-coincidence mode. Each serum dilution was tested in duplicate vials without bacteria to asses serum-induced nonspecific CL.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Survival of rough and smooth strains of Brucella abortus in bovine mammary gland macrophages.
Chronic bovine brucellosis is characterized by persistent infection of the mammary gland. The interaction of live Brucella abortus with bovine mammary gland macrophages was studied in vitro. Opsonization of smooth B abortus strain 2308 and rough strain 45/20 was required for phagocytosis by mammary gland macrophages. When opsonized with specific antiserum, strains 2308 and 45/20 stimulated a considerable oxidative burst when phagocytized by mammary gland macrophages. Intracellular survival rates for strain 2308 were significantly higher than those for strain 45/20. After being phagocytized, B abortus localized in phagosomes and phagolysosomes of mammary gland macrophages.
Animals↗
Assessment of bovine mammary gland macrophage oxidative burst activity in a chemiluminescence assay.
A major bactericidal mechanism of neutrophils and macrophages is the generation of toxic oxygen-free radicals upon phagocytosis of microbes. Studies were conducted to assess the oxidative metabolism of bovine mammary gland macrophages. Bovine mammary gland macrophages were challenge exposed with a variety of phagocytic stimuli in an in vitro, luminol-assisted chemiluminescence assay. A measurable oxidative burst was observed when macrophages were challenge exposed with heat-aggregated bovine immunoglobulin, opsonified zymosan, and nonosponified zymosan. Addition of superoxide dismutase decreased mammary gland macrophage chemiluminescence in a dose-dependent manner. Brucella abortus, when opsonified with antiserum, lacteal antibody, or normal serum, produced an oxidative event, whereas nonopsonified B abortus did not. When challenge exposed with phagocytic stimuli, mammary gland macrophages produced an oxidative burst similar to that produced by other phagocytes for which an oxidative event is known to be bactericidal.
Animals↗