Refine search
Results 91-100 of 484
Evaluation of pregnant rabbits as a laboratory model for bovid herpesvirus-4 infection
1990
Naeem, K. | Caywood, D.D. | Werdin, R.E. | Goyal, S.M.
A field strain (87-8363) of bovid herpesvirus-4 (BHV-4) isolated from an aborted bovine fetus was used to inoculate pregnant rabbits. Eleven rabbits in midgestation were alloted to 4 groups consisting of 3 infected groups and 1 control group. Rabbits were inoculated with BHV-4 or mock-infected cell culture preparations via IV, intravaginal, and intrauterine routes. Mild vulvovaginitis and endometritis were observed after intravaginal and IV inoculation of BHV-4, whereas intrauterine inoculation of BHV-4 resulted in abortion of hemorrhagic fetuses and nonsuppurative endometritis. Virus was successfully isolated from organ explants of fetal tissues. Rabbits seroconverted 1 week after infection as detected by results of an indirect immunofluorescence assay.
Show more [+] Less [-]Effects of age and prosthesis material on in vitro cartilage retention of laryngoplasty prostheses in horses
1990
Dean, P.W. | Nelson, J.K. | Schumacher, J.
Cartilage retention strengths of laryngoplasty prostheses were compared in larynges of 2-, 3-, and 4-year-old horses, using doubled polyester and expanded polytetrafluoroethylene prostheses. Bilateral laryngoplasties were performed on each of 15 (seven 2-year-old, two 3-year-old, and six 4-year-old) larynges, which were collected at an abbatoir. Prostheses were secured to a mechanical testing machine, and tension causing arytenoid cartilage abduction was applied, until total failure of the cartilage or prosthesis resulted. Tension caused cricoid cartilage failure in 1 specimen, and muscular process cartilage failure in the remainder. There was no significant effect of age, prosthetic material, or side of prosthesis placement on cartilage retention of the prostheses. Additionally, frequency of multiple load-displacement peaks, indicating partial muscular process failure, was not affected by age or prosthetic material variables.
Show more [+] Less [-]Influence of variable content of dietary zinc on copper metabolism of weanling foals
1990
Bridges, C.H. | Moffitt, P.G.
The influence of variable zinc content (29.1, 250, 1,000 and 2,000 mg/kg of dry weight) in a basic diet containing 7.7 mg of copper/kg on the ability of weanling foals to maintain normal copper balance was investigated. Serum copper and zinc concentrations were monitored, and terminal hepatic copper and zinc contents were measured in 4 weanling foals fed the basic diet containing 29.1 mg of zinc/kg and in 2 foals each fed the higher-zinc diets. Foals fed the lower-zinc diets (29.1 and 250 mg/kg) maintained normal serum copper and zinc concentrations for 14 to 15 weeks, whereas those fed the 2 higher-zinc diets became hypocupremic within 5 to 6 weeks and were lame within 6 weeks, owing to cartilaginous disease characteristic of osteochondritis dissecans. Serum zinc concentration in the foals fed the 2 higher-zinc diets increased to > 2 microgram/ml within 2 weeks. Foals fed the high-zinc diets became lame after serum copper concentration had remained at 0.3 microgram/ml for > 1 week. Serum copper concentration in these arthritic foals was less than or equal to 0.2 microgram/ml at the end of the study. In lame foals, fractures of the cartilage of the articular and growth physes occurred through the zone of hypertrophic cells, and varied from bilateral to unilateral and from small to large. Free masses and flaps of cartilage attached to one side were numerous.
Show more [+] Less [-]Comparison of two antigens for use in an enzyme-linked immunosorbent assay to detect African swine fever antibody Full text
1990
Pastor, M.J. | Arias, M. | Escribano, J.M.
Comparison of two antigens for use in an enzyme-linked immunosorbent assay to detect African swine fever antibody
1990
Pastor, M.J. | Arias, M. | Escribano, J.M.
Two African swine fever virus (ASFV) antigens were tested for use in an ELISA to detect antibody to ASFV. Antigens used were the cytoplasmic soluble fraction (CS-P) of infected cells grown in the presence of porcine serum and the semipurified viral structural protein VP73 (SVP73). Both antigens were tested by ELISA against 72 sera obtained during several ASF field episodes and from ASFV-inapparent carriers. Of the 72 sera, only 2.8% had positive results by ELISA against CS-P antigen; 60% of positive-reacting sera (to both antigens) had higher ELISA values when the CS-P antigen was used. Samples (with positive results) that reacted only to CS-P antigen had results confirmed by immunoblot analysis. Such sera reacted against ASFV-infection proteins IP25, IP25.5, and IP30, but not against IP73. In time-course experiments to detect appearance of ASFV-antibodies in infected miniature pigs, antibodies were detected by immunoblot analysis on postinoculation day (PID) 8. At that time, only the polypeptides IP25, IP25.5, IP30, and IP31 were recognized; IP73 and IP12 were first detected 3 and 4 days later, respectively. In the same experiments, ASFV antibodies were detected by ELISA, using CS-P or SVP73 antigens, on PID 7 and 9, respectively. These results could explain the percentage of sera not having positive results by ELISA using SVP73 antigen, if the sera were obtained from ASFV-infected pigs during the first days of infection before induction of antibody response against the IP73 protein. This feature makes the use of CS-P antigen advantageous in early serologic detection of AFSV-infected pigs.
Show more [+] Less [-]Comparison of two antigens for use in an enzyme-linked immunosorbent assay to detect African swine fever antibody Full text
1990
Pastor, M. J. | Arias, Marisa | Escribano, J. M.
Two African swine fever virus (ASFV) antigens were tested for use in an ELISA to detect antibody to ASFV. Antigens used were the cytoplasmic soluble fraction (CS-P) of infected cells grown in the presence of porcine serum and the semipurified viral structural protein VP73 (SVP73). Both antigens were tested by ELISA against 72 sera obtained during several ASF field episodes and from ASFV-inapparent carriers. Of the 72 sera, only 2.8% has positive results by ELISA against CS-P antigen; 60% of positive-reacting sera (to both antigens) had higher ELISA values when the CS-P antigen was used. Samples (with positive results) that reacted only to CS-P antigen had results confirmed by immunoblot analysis. Such sera reacted against ASFV-infection proteins IP25, IP25.5, and IP30, but not against IP73. In time-course experiments to detect appearance of ASFV-antibodies in infected miniature pigs, antibodies were detected by immunoblot analysis on postinoculation day (PID) 8. At that time, only the polypeptides IP25, IP25.5 IP30, and IP31 were recognized; IP73 and IP12 were first detected 3 and 4 days later, respectively. In the same experiments, ASFV antibodies were detected by ELISA, using CS-P or SVP73 antigens, on PID 7 and 9, respectively. These results could explain the percentage of sera not having positive results by ELISA using SVP73 antigen, if the sera were obtained from ASFV-infected pigs during the first days of infection before induction of antibody response against the IP73 protein. This feature makes the use of CS-P antigen advantageous in early serologic detection of ASFV-infected pigs.
Show more [+] Less [-]Breda virus (Toroviridae) infection and systemic antibody response in sentinel calves
1990
Koopmans, M. | Cremers, H. | Woode, G. | Horzinek, M.C.
Enzyme-linked immunosorbent assays were established to detect Breda virus antigen in feces and homologous antibodies of the IgG1, IgM, and IgA isotypes in serum. With the aid of solid-phase immune-electron microscopy, torovirions in fecal material were observed. The course of natural infection was studied in 10 sentinel calves that had been obtained from different farms, and housed together at 1 week of age. They were separated from other cattle until the age of 10 months. Up to the age of 4 months, all calves regularly excreted Breda virus in the feces. Irrespective of the existence of IgG1 isotype maternal antibodies, all calves had early IgM responses in serum, but lack of IgA seroconversion. In 7 calves, antibody titer decreased below detection, whereas 3 calves had an isotype switch, resulting in persistent IgG1 titer. After introduction into the dairy herd at 10 months of age, all calves had diarrhea, and shedding of Breda virus was observed in 8 of them. Seroconversion for all antibody isotypes was observed, indicating lack of mucosal memory. In contrast, coronavirus infection in the presence of maternal antibodies led to isotype switch in all calves but one, and a memory response was observed after introduction into the dairy herd.
Show more [+] Less [-]Congenital malformations in sheep resulting from in utero inoculation of Cache Valley virus
1990
Chung, S.I. | Livingston, C.W. Jr | Edwards, J.F. | Gauer, B.B. | Collisson, E.W.
Serologic evidence indicated that an episode of congenital abnormalities in sheep was caused by Cache Valley virus (CVV), a bunyavirus indigenous to the United States. To determine the teratogenic potential of CVV in sheep, fetuses were infected in utero between 27 and 54 days of gestation with an isolate (CK-102) obtained in 1987 from a sentinel sheep in San Angelo, Texas. The dams of these fetuses were euthanatized between 28 and 75 days after inoculation, and the fetuses were examined for malformations. Twenty-eight of 34 fetuses had congenital abnormalities, including arthrogryposis, hydranencephaly, mummification, reabsorption, and oligohydroamnion. Virus was isolated from the allantoic fluid of 11 of 17 fetuses euthanatized at less than 70 days of gestation. The virus-positive fetuses, which were all negative for CVV-neutralizing antibody, had lesions ranging from none to severe arthrogryposis and hydranencephaly. Virus was not recovered from the allantoic fluid of fetuses after 76 days' gestation when CVV-specific antibody could be detected in 5 of 8 fetuses examined. The 2 fetuses infected on days 50 and 54 of gestation appeared normal and 1 had antibody to CVV.
Show more [+] Less [-]Effects of inflammation and aqueous tear film deficiency on conjunctival morphology and ocular mucus composition in cats
1990
Johnson, B.W. | Whiteley, H.E. | McLaughlin, S.A.
An experimental model of keratoconjunctivitis sicca (KCS) was produced by removing the lacrimal gland and the gland of the third eyelid from the left eye of 6 cats. The right eye of each cat was left intact and used as a control. After 2 weeks, cats were euthanatized and the central portion of the upper eyelid from both eyes of each cat was excised. Histologic sections were stained with either hematoxylin and eosin or with a battery of biotinylated lectins including concanavalin A (conA), soybean agglutinin (SBA), wheat germ agglutinin (WGA), succinylated wheat germ agglutinin (S-WGA), Ulex europaeus agglutinin I (UEA), Dolichos biflorus agglutinin (DBA), Ricinus communis agglutinin (RCA), peanut agglutinin (PNA), and PNA pretreated with neuraminidase. Consistent differences in histologic features were not observed between conjunctivas with KCS and control conjunctivas. A variable degree of mononuclear cell infiltration of the substantia propria was observed in control conjunctivas and those with KCS. In both groups, conjunctival goblet cell density decreased and epithelial stratification increased as the degree of submucosal inflammatory cell infiltration increased. Lectin binding sites for DBA, WGA, S-WGA, UEA, PNA, and PNA pretreated with neuraminidase were detected on conjunctival goblet cells of conjunctivas with KCS and control conjunctivas. The mucus/glycocalyx layer of conjunctival epithelial cells in both groups of conjunctivas bound lectins RCA, WGA, UEA, and conA, but inconsistently bound S-WGA. In both groups, DBA principally bound to the mucus layer overlying normal epithelium, whereas PNA pretreated with neuraminidase consistently bound to the mucus layer of stratified epithelial surfaces free of goblet cells. Binding of SBA to goblet cells and the mucus/glycocalyx layer was variable.
Show more [+] Less [-]Effects of marketing stress on fecal excretion of Salmonella spp in feeder calves
1990
Corrier, D.E. | Purdy, C.W. | DeLoach, J.R.
Fecal samples were collected from 200 feeder-calves on farms in Tennessee, after assembly at a Tennessee auction market, and after transport to a Texas feedyard. A final fecal sample was collected from each calf after 30 days of feedyard confinement. The fecal samples were cultured for the presence of Salmonella spp. Salmonella isolates were serotyped and antimicrobial drug-resistance patterns determined. The number of calves fecal culture-positive for Salmonella spp increased from 0 on the Tennessee farms and auction market to 3/200 (1.5%) at entry into the Texas feedyard, and 16/200 (8%) after 30 days of feedyard confinement. Salmonella serotypes isolated and the number of isolates of each serotype were S reading (8), S cerro (4), S newbrunswick (3), S anatum (2), and S typhimurium (copenhagen; 2). All Salmonella isolates were resistant to 5 or more of 13 antimicrobial drugs tested. Salmonella reading isolates were resistant to 10 or 11 of 13 antimicrobial drugs. The results indicated that the calves could have been infected with Salmonella spp prior to or during the course of the study, and that marketing stress as they moved from farm through feedyard may have induced fecal excretion of salmonellae. In addition, the pattern of antimicrobial drug resistance in the Salmonella isolates was broad.
Show more [+] Less [-]Evaluation of serologic and cellular immune responses of cattle to a nonlipopolysaccharide antigen from Brucella abortus
1990
Cows naturally infected with Brucella abortus developed antibody (Ab) responses to a nonlipopolysaccharide antigen (NLA) purified from B abortus strain 1119-3. Sera from strain 19-vaccinated cows did not have detectable amounts of Ab. Weak lymphoproliferative responses to NLA were observed in blood mononuclear cell suspensions obtained from infected cows. There was no evidence of NLA-specific lymphoproliferation in cell suspensions from healthy cows. Nonlipopolysaccharide antigen binding to bovine blood mononuclear cells was observed by antigen-consumption assays and direct binding of radiolabeled antigen. Cells from infected cows bound less NLA than did cells from healthy cows when assays were conducted with intact blood mononuclear cell preparations (monocytes plus lymphocytes). Monocytes obtained from any group did not bind NLA. Purified B lymphocytes from infected and healthy vaccinated cows bound about 3 times more NLA than did T lymphocytes, but there were no apparent differences between the 2 groups in extent of binding. Results of the study indicate that bovine lymphocytes have binding sites for a NLA purified from B abortus strain 1119-3.
Show more [+] Less [-]Effects of Mycoplasma hyopneumoniae and Actinobacillus (Haemophilus) pleuropneumoniae infections on alveolar macrophage functions in swine
1990
Alveolar macrophages were collected at necropsy from pigs inoculated with Mycoplasma hyopneumoniae or Actinobacillus pleuropneumoniae or both and were tested for phagocytic capabilities, using in vitro techniques. Macrophages from noninoculated littermates were used as controls. Alveolar macrophages from pigs inoculated with either M hyopneumoniae or A pleuropneumoniae had significantly (P < 0.05 to P < 0.0025) higher phagocytic capacity than that of noninoculated controls. Macrophages from A pleuropneumoniae-inoculated pigs were comparatively more stimulated than were those from M hyopneumoniae-inoculated pigs. Pigs inoculated with M hyopneumoniae and then challenge-exposed with A pleuropneumoniae 2 and 4 weeks later had greatly reduced phagocytosis. Infection with M hyopneumoniae or A pleuropneumoniae caused stimulation of alveolar macrophage functions, and M hyopneumoniae infections may have suppressed phagocytic responses when pigs were challenge-exposed with a secondary pathogen (A pleuropneumoniae). This potential suppression may represent a prediposition of the host by M hyopneumoniae to secondary bacterial infections.
Show more [+] Less [-]