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Biomedical subjects

T E Besser

Publications and source records attributed to T E Besser.

At least 55 records · Page 3Linked to original sources
PubMed1997

Expression of immunoglobulin G1 receptors by bovine mammary epithelial cells and mammary leukocytes.

The objective of this study was to identify and evaluate expression of IgG1 receptors by different cell types in mammary tissue sections and digest-dispersed cells from the bovine mammary gland. An immunohistochemical system utilizing avidin-biotin-peroxidase complex demonstrated epithelial expression of IgG1 receptors in mammary tissue sections from cows producing colostrum but not from cows in lactation. Fluorescence flow cytometry demonstrated that cells dispersed in digests from both tissues producing colostrum and lactating tissues selectively bound IgG1. Fluorescence flow cytometry, using monoclonal antibodies to cell surface molecules, cytokeratin, and IgG1, revealed that leukocytes constituted the largest percentage of cells and were the predominant cell type binding IgG1 in mammary tissue digests. Although IgG1 binding to epithelial cells predominated in the gland during colostrum production in situ, digestion and filtration to produce single cell suspensions resulted in the loss of large numbers of epithelial cells. Studies of Ig binding of cells produced by enzymatic digestion must account for the types of cells surviving the digestion process.

Animals↗
PubMed1997

Effect of prolactin on in vitro expression of the bovine mammary immunoglobulin G1 receptor.

Explants of mammary tissue from cows in late pregnancy were incubated for 72 h in serum-free, hormonally defined media to investigate the regulation of the bovine mammary IgG1 receptor. Treatments included incubation in basal medium alone, basal medium plus estradiol-17 beta, basal medium plus prolactin, or basal medium plus estradiol-17 beta and prolactin. alpha-Lactalbumin production was measured by radioimmunoassay in culture supernatants collected at 24, 48, and 72 h. Explants were examined immunohistochemically for expression of the IgG1 receptor at 24, 48, and 72 h. alpha-Lactalbumin concentrations increased, and IgG1 receptor expression decreased, by 72 h with explants cultured in the medium containing prolactin. Results suggest that, in addition to its positive lactogenic effect, prolactin decreases expression of the bovine mammary IgG1 receptor.

Animals↗
PubMed1996

Evaluation of a coagulase-negative variant of Staphylococcus aureus as a cause of intramammary infections in a herd of dairy cattle.

A coagulase-negative variant of Staphylococcus aureus was identified in a herd of 250 lactating dairy cows. During testing of the entire herd, this strain of S aureus was isolated from aseptically collected milk samples of 25 cows. Cows with intramammary infections attributable to coagulase-negative S aureus had an increased somatic cell count in their milk, which was indicative of mastitis infection. Speciation of the Staphylococcus organisms was made, using a series of biochemical tests. A strain of a coagulase-positive S aureus also caused intramammary infections in the herd and shared identical biochemical characteristics with the coagulase-negative strain. Moreover, both strains could not be typed by the use of the International Set of Bovine Phages. Analysis of these findings indicated that a coagulase-negative variant of S aureus can cause intramammary infections in cattle, coagulase-negative variants of S aureus that cause mastitis can be more prevalent in herds than coagulase-positive variants, and clinicians should avoid misclassifying coagulase-negative S aureus as organisms that are clinically unimportant.

Animals↗
PubMed1996

Prediction of calf mortality by use of tests for passive transfer of colostral immunoglobulin.

OBJECTIVE: To examine the ability of several commonly used tests for evaluation of passive transfer of immunoglobulin to predict mortality in dairy replacement heifers. DESIGN: Prospective observational study. ANIMALS: 246 dairy replacement heifers between 1 and 8 days of age. PROCEDURE: Using serum samples obtained from each calf, total serum protein concentration and results of zinc sulfate turbidity, sodium sulfite turbidity, radial immunodiffusion, and glutaraldehyde coagulation were determined. Calves were monitored for 100 days, and relative risks for death were calculated. Logistic regression models predicting death also were developed. RESULTS: None of the logistic regression models detected a significant association between test results and mortality. The greatest relative risks of mortality were observed in calves with serum protein concentrations < 4.5 g/dl, serum IgG1 concentrations < 500 mg/dl, and sodium sulfite test scores < 1+. CLINICAL IMPLICATIONS: Calves with lower passive transfer values had increased risk of death; however, failure of passive transfer is not an infallible predictor of mortality.

Animals↗
PubMed1996

Role of maternally derived circulating antibodies in protection of neonatal swine against porcine group A rotavirus.

The ability of maternally derived antibodies in the circulation of neonatal pigs to protect against challenge with virulent porcine group A rotavirus (OSU strain) was evaluated. Groups of neonatal pigs with nondetectable (group 1), low (group 2), or high (group 3) serum levels of OSU rotavirus-specific maternally derived antibodies were challenged with virulent OSU rotavirus at 3 days of age and monitored for infection and disease. Control pigs were sham-inoculated with diluent at 3 days of age. Although all virus-inoculated pigs shed rotavirus and developed diarrhea, group 3 pigs developed significantly less severe diarrhea and shed for significantly fewer days than group 1 and 2 pigs, and they maintained appetites and weight gains comparable to sham-inoculated controls. It was concluded that circulating maternally derived antibodies play a significant role in mitigating clinical disease following rotavirus infection in neonatal swine and that the protection afforded by these antibodies is titer dependent.

Animals↗
PubMed1996

Rapid differentiation of Mycobacterium avium and M. paratuberculosis by PCR and restriction enzyme analysis.

Mycobacterium avium subsp. avium (M. avium) and M. avium subsp. paratuberculosis (M. paratuberculosis), intracellular bacteria that can cause chronic granulomatous enteritis in cattle, are difficult to distinguish on the basis of growth and biochemical characteristics. We report the development of a PCR-based strategy for the rapid differentiation of isolates of M. avium from isolates of M. paratuberculosis. Restriction fragment length polymorphism was identified by PCR amplification and subsequent restriction enzyme digestion with PstI of a 960-bp fragment of the 65-kDa heat shock protein (hsp65) from 21 clinical isolates of M. paratuberculosis and 14 isolates of M. avium. These results indicate that a restriction fragment length polymorphism in the hsp65 gene can be used for the rapid differentiation of clinical isolates of M. paratuberculosis and M. avium.

Animals↗
PubMed1996

Prevalence of coagulase-positive staphylococci, other than Staphylococcus aureus, in bovine mastitis.

OBJECTIVE: To determine prevalence and relevance of coagulase-positive Staphylococcus hyicus and S intermedius intramammary infections (IMI) in dairy cows and determine the ability of the 4-hour tube coagulase (TC) test to differentiate the coagulase-positive staphylococci (CPS). DESIGN: Prevalence of CPS was determined for primiparous cows (point prevalence and prevalence at first parturition) and multiparous cows (point prevalence) of 2 herd groups: < 6% CPS IMI prevalence = low prevalence (LP); > 10% CPS IMI prevalence = high prevalence (HP). SAMPLE POPULATION: For prevalence, cows of 22 dairy herds. For TC, 1,038 CPS strains isolated from cow milk. PROCEDURE: Speciation of CPS from aseptically collected composite milk samples was performed. Coagulase-positive isolates from 4 cow groups were tested for their ability to coagulate rabbit plasma by 4 hours: LP and HP primiparous cows at parturition, and LP and HP cows any time after first parturition. RESULTS: Of 487 CPS in the prevalence study, 82.1% were S aureus, 17.7% were coagulase-positive S hyicus, and 0.2% were S intermedius. Of all CPS IMI in LP herds, 34% were coagulase-positive S hyicus; of all CPS IMI in HP herds, 9% were coagulase-positive S hyicus. Coagulase-positive S hyicus appeared to persist to the end of lactation in 4 cows (mean linear somatic cell count = 3.7). The TC test was > or = 97% sensitive, < or = 33% specific, and had a predictive value positive range of 60 to 97% for S aureus isolates. CONCLUSION: Coagulase-positive S hyicus appears capable of inducing chronic, low-grade IMI. Staphylococcus intermedius does not appear to be an important mastitis pathogen. The TC test is not valid to use as the sole method to differentiate CPS species.

Animals↗
PubMed1996

Optimizing performance of a qualitative zinc sulfate turbidity test for passive transfer of immunoglobulin G in calves.

OBJECTIVE: To determine optimal zinc sulfate test solution concentration for detecting failure of passive transfer in calves. ANIMALS: 235 calves (1 to 8 days old) from a calf-rearing operation in central Washington state. PROCEDURE: Zinc sulfate turbidity tests, using 200-, 250-, 300-, 350-, and 400-mg/L test solutions, were performed on calf serum. These increasing concentrations were evaluated for detection of failure of passive transfer. Using 1,000 mg of IgG1/dl as the threshold for adequate passive transfer, sensitivity, specificity, and accuracy of classification were determined by comparing the zinc sulfate test results with serum IgG1 concentration (mg/dl) measured by radial immunodiffusion. RESULTS: The 200-mg/L zinc sulfate turbidity test solution was 100% sensitive; however, specificity was only 25.5%. Increasing concentrations of zinc sulfate test solution up to 350 mg/L improved specificity with either no change or small decreases in sensitivity. CONCLUSION AND CLINICAL RELEVANCE: The endpoint of the traditional 208-mg/L zinc sulfate turbidity test for failure of passive transfer in calves is too high. Increased test solution concentrations improve specificity with only minor adverse effects on sensitivity.

Animals↗
PubMed1995

Sensitivity of bacteriologic culture for detection of Escherichia coli O157:H7 in bovine feces.

The sensitivities of several plating and broth enrichment methods for the detection of Escherichia coli O157:H7 in (i) bovine fecal samples directly inoculated with E. coli O157:H7, (ii) fecal samples from cattle in herds previously positive for E. coli O157:H7, and (iii) fecal samples from calves shedding E. coli O157:H7 after experimental oral inoculation were compared. Three enrichment protocols and three plating protocols were evaluated with directly inoculated fecal samples. All broth enrichment methods were superior to direct plating when they were combined with subsequent plating on sorbitol-MacConkey with cefixime and tellurite (SMACct). SMACct was the most sensitive plating medium, and the three alternative broth enrichment methods gave similar improvements in sensitivity. Of 351 fecal samples from known positive herds, 24 samples (6.8%) were positive by one or more methods. By the most sensitive plating method, cultures of 10-g samples were slightly more sensitive (19 of 351 [5.4%]) than cotton-tipped swab fecal samples (14 of 351 [4.0%]); however, this difference was not significant. For samples from calves orally inoculated with E. coli O157:H7, separation by immunomagnetic beads was slightly more sensitive (79%) than broth enrichment followed by plating at two dilutions (10(-3) and 10(-4)) (71%); however, this difference was not significant. The combination of overnight enrichment of swab fecal samples (0.1 g) and plating on SMACct at two dilutions (10(-3) and 10(-4)) appears to be a sensitive method for detection in large-scale studies involving hundreds of samples per week.

Animals↗
PubMed1995

Immunoglobulin G1 transfer into induced mammary secretions: the effect of dexamethasone.

The purpose of this study was to correlate the time of administration of the synthetic glucocorticoid dexamethasone with IgG1 concentrations in hormonally induced mammary secretions of nonpregnant cattle. Nonpregnant, nonlactating Holsteins were randomly assigned to three experimental groups of 8 cows each, and all were given .05 mg/kg of estrogen and .125 mg/kg of progesterone by subcutaneous injection every 12 h for 7 d. In addition, cows in groups 1 and 2 received dexamethasone (20 mg/d) on d 8 to 10 and on d 11 to 13, respectively. Group 3 cows were not given dexamethasone. The IgG1 concentrations in the mammary secretions of all three treatment groups rose steadily during d 1 to 7. The IgG1 concentrations in mammary secretions of groups 1 and 2 decreased sharply within 3 d of the first dexamethasone injection. The IgG1 concentrations in mammary secretions of group 3 also tended to peak and then decrease, but the decreases were generally later than those of cows receiving dexamethasone. The results indicate that the IgG1 transfer that occurs during induction of lactation is affected by glucocorticoid administration in a pattern similar to that reported during colostrum formation in pregnant cows.

Animals↗
PubMed1994

The importance of colostrum to the health of the neonatal calf.

Colostrum feeding is the means by which newborn calves acquire passive immunity to infectious agents. The ability of the newborn calf to absorb colostral antibodies is limited to the first few hours of life. In most cases, natural suckling from the dam is the best method for beef-breed calves to obtain optimum passive immune protection, but in some cases intervention and hand feeding are indicated. The details of when and how to intervene in the passive transfer process are discussed.

Animals↗
PubMed1994

The prevalence of Escherichia coli O157.H7 in dairy and beef cattle in Washington State.

Escherichia coli O157.H7 was found in 10 of 3570 (0.28%) faecal samples from dairy cattle in 5 of 60 herds (8.3%). Several tentative associations with manure handling and feeding management practices on dairy farms were identified. Faecal/urine slurry samples, bulk milk samples, and milk filters from dairy herds were negative for E. coli O157.H7. E. coli O157.H7 was also isolated from 10 of 1412 (0.71%) faecal samples from pastured beef cattle in 4 of 25 (16%) herds. The prevalence of E. coli O157.H7 excretion in feedlot beef cattle was 2 of 600 (0.33%). The identification of cattle management practices associated with colonization of cattle by E. coli O157.H7 suggests the possibility that human E. coli O157.H7 exposure may be reduced by cattle management procedures.

Animals↗
PubMed1994

Characteristics of antibiotic-resistant Escherichia coli O157:H7 in Washington State, 1984-1991.

The resistance of Escherichia coli O157:H7 to amoxicillin/clavulanic acid, ampicillin, ceftazidime, ceftriaxone, cefuroxime, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, streptomycin, sulfisoxazole, tetracycline, ticarcillin, tobramycin, and trimethoprim-sulfamethoxazole was examined, and resistant strains were characterized. All 56 isolates collected between 1984 and 1987 were susceptible to all antibiotics tested; 13 (7.4%) of 176 strains isolated between 1989 and 1991 were resistant to streptomycin, sulfisoxazole, and tetracycline. lambda-restriction fragment length polymorphism analysis suggested that the 13 resistant strains belonged to nine different clones. The emerging resistance of E. coli O157:H7 to antibiotics could portend an increased prevalence of this pathogen in food animals that receive antibiotics. Antimicrobial resistance of E. coli O157:H7 could be useful as a rapid epidemiologic marker and as a way to select this pathogen from suspected vehicles of transmission, but this resistance could also complicate therapeutic trials with sulfa-containing antibiotics.

Bacterial Toxins↗