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Evaluation of total protein content in tears of dogs by polyacrylamide gel disk electrophoresis
1992
Barrera, R. | Jimenez, A. | Lopez, R. | Mane, M.C. | Rodriguez, J.F. | Molleda, J.M.
Concentration of total proteins was measured and sodium dodecyl sulfate-polyacrylamide gel disk electrophoresis was performed on tear and plasma samples obtained from 26 healthy dogs, and the results were compared. Mean +/- SEM concentration of total proteins in tears was 0.63 +/- 0.04 g/dl, and significant effects of age or gender were not found. The protein composition of tears in dogs was complex, and bands from light and heavy chains of immunoglobulins were identified by electrophoresis.
Mostrar más [+] Menos [-]Effect of calf age and Salmonella bacterin type on ability to produce immunoglobulins directed against Salmonella whole cells or lipopolysaccharide
1992
Roden, L.D. | Smith, B.P. | Spier, S.J. | Dilling, G.W.
A commercially available Salmonella bacterin was administered to Holstein calves starting at 1 to 19 weeks of age. Serum samples were obtained before administering bacterin and at 2-week intervals thereafter. An ELISA with Salmonella dublin lipopolysaccharide (LPS) or S dublin whole cells as antigen, was used to measure specific IgG and IgM responses. Antibody responses to LPS were not detected from calves < 12 weeks old inoculated with killed bacterin. Immunoglobulin responses to whole-cell antigen were detected from all age groups of calves inoculated with the same killed Salmonella bacterin. Calves < 11 weeks old are able to produce immunoglobulins to some whole-cell antigens, but are unable to produce anti-LPS immunoglobulins when inoculated with killed Salmonella bacterin. This age-related response to killed Salmonella antigens may account, in part, for increased susceptibility to salmonellosis in calves < 12 weeks old. In comparison to the response for killed antigen, 8 calves given modified-live aromatic-dependent S dublin bacterin at 1 to 3 weeks of age had detectable anti-LPS immunoglobulin after immunization, although the response was not as rapid and was of a lesser magnitude than that of older calves given killed Salmonella bacterin.
Mostrar más [+] Menos [-]Histomorphometric analysis of the rumen of sheep during development
1992
Franco, A. | Regodon, S. | Robina, A. | Redondo, E.
Histomorphometric and scanning electron microscopic analyses were carried out on 74 embryos and fetuses and 20 sheep (early postnatal to adult age). Histodifferentiation of the rumen took place at 33 days of fetal fife. Ruminal pillars were observed at 42 days, and at 61 days, ruminal papillae appeared as evaginations of the epithelial stratum basale. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life; thereafter, numbers decreased gradually and subsequently stabilized in postnatal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Age and diet were recognized as factors that determine the structure of the ruminal mucosa. Growth curves and formulas were set out for each tissue layer.
Mostrar más [+] Menos [-]Effect of age on activation of porcine intestinal guanylate cyclase and binding of Escherichia coli heat-stable enterotoxin (STa) to porcine intestinal cells and brush border membranes
1992
Jaso-Friedmann, L. | Dreyfus, L.A. | Whipp, S.C. | Robertson, D.C.
Development of age-dependent resistance to enterotoxigenic Escherichia coli was studied, using isolated enterocytes and brush border membranes (BBM) from 7-day-old and 7-week-old pigs. Binding of 125I-labeled heat-stable (125I-STa) enterotoxin to enterocytes and BBM was specific, temperature- and time-dependent, saturable, and partially reversible. Scatchard analysis revealed a single class of receptors. Mean +/- SD avidity of binding (apparent affinity constant, Ka) of 125I-STa to enterocytes from 7-day-old and 7-week-old pigs was 2.14 +/- 0.29 X 10(8) and 2.72 +/- 0.25 X 10(8) L/mol, respectively. Numbers of STa receptors were calcuated to be 64,903 +/- 2,900/enterocyte for 7-day-old pigs and 53,029 +/- 3,117/enterocyte for 7-week-old pigs. Numbers of STa receptors expressed per milligram of BBM protein from 7-day-old pigs were 2.66 X 10(11), compared with 2.29 X 10(11) for BBM from 7-week-old pigs. By 5 minutes after addition of STa to reaction mixtures, intracellular cyclic guanosine monophosphate concentration increased 13.9-fold in enterocytes from 7-day-old pigs and 8.7-fold in enterocytes from 7-week-old pigs. The particulate guanylate cyclase activity associated with BBM from 7-week-old pigs was slightly more sensitive to low amounts of STa, compared with BBM from 7-day-old pigs; however, differences were not observed at intermediate and high amounts. These data indicate that lack of a secretory response to STa by older pigs is not attributable either to decreased numbers of STa receptors or to decreased signal response between the STa receptor and membrane-bound guanylate cyclase. Development of age-dependent resistance by porcine small intestine to STa appears to be attributable to steps in the secretory pathway that respond to increased concentration of cyclic guanosine monophosphate.
Mostrar más [+] Menos [-]Risk factors for abomasal volvulus and left abomasal displacement in cattle
1992
Constable, P.D. | Miller, G.Y. | Hoffsis, G.F. | Hull, B.L. | Rings, D.M.
A hospital-based case-control study was conducted to evaluate and compare risk factors for abomasal volvulus (AV) and left displaced abomasum (LDA) in cattle. Medical record abstracts were derived from 17 North American veterinary schools by the Veterinary Medical Data Program for all cattle admitted between Jan 1, 1977 and Dec 31, 1986, and for those with a diagnosis of AV or LDA. From a total of 108,956 individual cattle records, 1,036 cases of AV and 7,695 cases of LDA were identified, with a ratio of LDA to AV cases of 7.4 to 1. In-hospital mortality was 23.5% for AV and 5.6% for LDA. Age, breed, gender, and season each had significant (P < 0.05) effects on risk for AV and LDA. Risk for AV and LDA increased with increasing age, with greater risk in cattle aged 4 to 7 years. Dairy cattle were at higher risk of developing AV (adjusted odds ratio, 36.4) and LDA (adjusted odds ratio, 95.2) than were beef cattle. The odds of AV in Brown Swiss cattle were significantly (P < 0.0001) lower, and the odds of LDA in Guernsey cattle were significantly (P < 0.0001) higher than those in Holstein cattle. Female cattle were also at higher risk of developing AV (adjusted odds ratio, 3.3) and LDA (adjusted odds ratio, 29.1) than were male cattle. The odds of AV and LDA varied considerably throughout the year, with the lowest number of cases observed in autumn. Seasonal development of AV differed significantly (P < 0.0001) from that Of LDA, with the odds of AV and LDA being highest in January and March, respectively. The medical records for all cattle with AV and LDA examined at the teaching hospital over a 10- and 5-year period, respectively, were reviewed, and the time interval since parturition, as well as the existence and nature of concurrent disease, were recorded. Proportionately fewer cases of AV than LDA developed during the first 2 weeks after parturition (28.3% of AV cases vs. 57.0% of LDA cases). Concurrent disease existed in 30.4% of AV cases and 53.6% of LDA cases, with the rates of concurrent disease differing significantly (P < 0.0001) between the 2 groups. The misclassification rate for data generated at the teaching hospital was estimated to be 6.5% for AV and 5.3% for LDA. On the basis of the findings of this study, we hypothesize that: abomasal atony is a prerequisite for AV and LDA; existence of an abdominal void immediately after parturition facilitates development of AV and LDA; normal rumen volume provides a moderately effective barrier against LDA; risk of LDA does not increase appreciably with advancing pregnancy; and the direction of abomasal displacement (AV or LDA) after abomasal atony and dilation is influenced principally by rumen volume.
Mostrar más [+] Menos [-]Fractional excretion of electrolytes in lactating dairy cows
1992
Fleming, S.A. | Hunt, E.L. | Brownie, C. | Rakes, A. | McDaniel, B.
Samples of serum and urine were obtained simultaneously from 56 healthy lactating cows to determine ranges of fractional excretion (FE) of calcium (Ca), phosphate (PO4), magnesium (Mg), sodium (Na), potassium (K), and chloride (Cl). Samples were obtained at 3 stages of lactation: period 1 = 1 to 7 days, 2 = 83 to 112 days, and 3 = 175 to 197 days. The FE of electrolytes were significantly different among periods 1, 2, and 3 for Ca (P < 0.001), PO4 (P < 0.025) and Mg (P < 0.025), but were not significantly different for Na, K, and Cl. Least squares mean FE of Ca was lowest in period 1 and not significantly different for periods 2 and 3, whereas mean FE values for PO4 and Mg were highest in period 2 and not significantly different for periods 1 and 3. The mean FE values of Na, K, and Cl did not change with stage of lactation. Age and category of milk production (high, medium, and low) did not influence the FE values of the electrolytes.
Mostrar más [+] Menos [-]Serum bile acid concentration in clinically normal cattle: comparison by type, age, and stage of lactation
1992
Craig, A.M. | Pearson, E.G. | Rowe, K.
Serum total bile acid concentrations were determined for various types and ages of cattle. There was extreme variability among all the cattle, but the variance was twice as large (0.50 vs 0.22 in logarithmic scale) for beef cattle than for dairy cattle. There was no significant difference in serum total bile acid concentrations between beef cattle and dairy cattle in midlactation. Values for calves < 6 weeks old and for 6-month-old heifers were significantly (P = < 0.05) lower than values for lactating dairy cows. The 5th to 95th percentile range of values (micromol/L) for beef cattle was 9 to 126; for lactating dairy cattle, 15 to 88; and for 6-month-old dairy heifers, 11 to 64.
Mostrar más [+] Menos [-]Retrospective evaluation of factors associated with the risk of seropositivity to Ehrlichia risticii in horses in New York state
1992
Atwill, E.R. | Mohammed, H.O. | Dubovi, E. | López Izquierdo, J.
A retrospective study was designed to determine the distribution of equine monocytic ehrlichiosis among the equine population in New York state, and to identify factors associated with risk of disease. Serum samples submitted to the diagnostic laboratory of the university during the period from January 1985 through December 1986 were examined for antibodies to Ehrlichia risticii, using the indirect fluorescent antibody technique. Factors evaluated included geographic origin and date of submission of the sample, and age, breed, and sex of the horse. Logistic regression analysis was used to identify which factors were significantly associated with the risk of seropositivity to E risticii, while simultaneously controlling for other factors. Of the 2,579 tested samples, 1,950 (76%) had positive results. Factors significantly associated with risk of seropositivity to E risticii were: breed of the horse (Thoroughbreds were 3 times more likely to have been exposed to E risticii, compared with non-Standardbred, non-thoroughbred breeds); sex (female horses were 2.7 times more likely to have been exposed, compared with male horses); age of the horse (the risk of being exposed to E risticii increased with age, peaked at around 12 years, and decreased thereafter); and month of submission (horses tested during November and December had the highest odds of being seropositive [odds ratio = 2.1], and horses tested during March through April were least likely to be seropositive [odds ratio = 0.5], compared with horses tested during January and February).
Mostrar más [+] Menos [-]Seroprevalence of ovine progressive pneumonia virus in sheep in the United States as assessed by analyses of voluntarily submitted samples
1992
Cutlip, R.C. | Lehmkuhl, H.D. | Sacks, J.M. | Weaver, Al
Ovine progressive pneumonia (OPP) is a lentivirus-induced disease of sheep in the United States that is similar, if not identical, to maedi/visna in many other countries. Prevalence estimates of seropositivity to this virus in sheep in the United States have been confined to limited groups or flocks of sheep and have varied from 1 to 90%. In this study of detection of antibodies against OPP virus, we found a lower general prevalence of antibodies to OPP virus in sheep than was previously reported. Of 16,827 sheep from 29 states in the United States, 26% were seropositive and 48% of 164 flocks that were tested had 1 or more seropositive sheep. Seropositivity to OPP virus for sheep within special categories was determined, although nonrandom samples that were available may have biased the results. Within regions of the United States, prevalence was highest in the Rocky Mountain region at 49% and lowest in the northern Atlantic region at 9%. Seropositive sheep were not evenly distributed among flocks, but were clustered in a few flocks of sheep. A high number of flocks had no or few seropositive sheep. Prevalence increased with age from 4% at < 1 year to a plateau of 34% at 4 years. Seropositivity was variable among breeds and was not associated with sex, wool class, or place of origin of ancestors.
Mostrar más [+] Menos [-]Bacterial survival, lymph node changes, and immunologic responses of cattle vaccinated with standard and mutant strains of Brucella abortus
1992
Cheville, N.F. | Jensen, A.E. | Halling, S.M. | Tatum, F.M. | Morfitt, D.C. | Hennager, S.G. | Frerichs, W.M. | Schurig, G.
Forty-eight cattle were used in 4 experiments; 6-week-old calves in experiments 1-3 (n = 24) and 10-month-old heifers in experiment 4 (n = 24). In experiments 1-3, 7 groups of 3 calves each were inoculated SC with 5 strains of Brucella abortus: virulent strain 2308 (2 groups), vaccine strain 19 (2 groups), and mutant strains RB51, 19 delta 31K, and 19 delta SOD. Sera and lymph node tissues were examined at 2-week intervals for evidence of infection. At postinoculation (PI) week 12, 2 calves in each group were given dexamethasone for 5 days. Calves were then euthanatized and lymphoid tissue, spleen, liver, and bone marrow were examined for evidence of B abortus. Calves given strain 2308 had large numbers of bacteria in their lymph nodes, marked granulomatous lymphadenitis in the deep cortex, and loss of lymphoid cells in superficial cortical areas. In addition, they had high serum antibody titers at PI week 16. Calves given strain 19, or genetic mutants derived from strain 19, cleared bacteria from lymph nodes more rapidly, had less lymphoid destruction, and developed antibody titers that did not persist for 16 weeks. The RB51 strain (rough) was cleared most rapidly from lymphoid tissues and induced serum antibody responses only to the core of the lipopolysaccharide molecule. Treatment of calves with dexamethasone did not cause B abortus to reappear in tissues of any calves, nor did serum antibody titers increase. In experiment 4, designed to compare the effects of age, 4 groups (n = 4) of 10-month-old heifers were given 1 B abortus strain each (19, RB51, 19 delta 31K, or 19 deltaSOD), using the same methods. Results of bacteriologic culturing and antibody responses were similar to those in the calves, except that strain RB51 persisted longer in heifers. Results of these studies indicated that, in cattle, the genetically engineered deletion mutants of B abortus do not cause unusual lesions, do have characteristics that closely resemble the parental strain, and could be candidates for use in a live vaccine.
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