Biomedical subjects

T E Besser

Publications and source records attributed to T E Besser.

At least 73 records · Page 4Linked to original sources

PubMed1994

Cardiovascular lesions in bovine Marfan syndrome.

Bovine Marfan syndrome is a genetic disease with many of the clinical and pathologic manifestations of human Marfan syndrome. Major manifestations include ectopia lentis and aortic dilatation, aneurysm, and rupture. Affected cattle have a defect in fibrillin metabolism similar to that in human patients. Ten cattle were followed and their disease progression and lesions documented. Ages ranged from a term fetus (No. 9) to a 4-year-old cow (No. 4); three animals were male (Nos. 1-3) and seven were female (Nos. 4-10). Of eight animals (80%) that died or were euthanatized (Nos. 1-3, 5-9), six (75%) had severe cardiovascular lesions identified at necropsy. Gross cardiovascular lesions of bovine Marfan syndrome included cardiac tamponade secondary to aortic rupture (animal Nos. 3, 6, 8), dissecting aneurysms of the aorta and pulmonary artery (animal No. 5), and intrauterine cardiac tamponade secondary to rupture of the pulmonary artery (animal No. 9). Microscopically, Verhoeff Van Gieson-stained sections of aorta contained severe fragmentation of the elastic laminae in the aortic media, but the cystic medial necrosis seen in human Marfan aortae was not identified, even in the chronic aortic dissection. Ultrastructurally, affected aortic tissue was characterized by thin, dark elastic fibers with abundant, tangled microfibrils on the periphery. Swirls of collagen fibers and bundles of hypertrophic smooth muscle cells replaced damaged elastic laminae. Gross and microscopic cardiovascular lesions in bovine Marfan syndrome are similar to those in human Marfan syndrome. Bovine Marfan syndrome is a valuable model for investigation of molecular pathogenesis and treatment of human Marfan syndrome.

Aortic Dissection↗

PubMed1994

Evaluation of a kinetic enzyme-linked immunosorbent assay for detection of caprine arthritis-encephalitis virus-specific antibodies.

A kinetic indirect enzyme-linked immunosorbent assay (k-ELISA) was evaluated for detection of antibody to caprine arthritis-encephalitis virus (CAEV), using sodium dodecyl sulfate-treated CAEV-63 as antigen. Two hundred fifteen caprine sera submitted to the diagnostic laboratory were tested for CAEV antibody by the k-ELISA and by immunoprecipitation of [35S]-methionine-labeled CAEV. A k-ELISA positive cutoff point of 80 yielded a sensitivity of 94.4% and a specificity of 100%, as compared with immunoprecipitation. A k-ELISA cutoff point of 50 resulted in a sensitivity of 100%, with 95.6% specificity. When sera with k-ELISA scores between 50 and 80 were considered suspect, testing of 1,001 diagnostic sera resulted in < 1.5% suspect reactions. Using the 80 cutoff point, the CAEV k-ELISA had good sensitivity and specificity, with the added advantages of quick turn-around time, few suspect reactions, and adaptability to large numbers of samples

Animals↗

PubMed1994

Coagulase-positive Staphylococcus intramammary infections in primiparous dairy cows.

Objectives were to determine the prevalence of coagulase-positive staphylococcal IMI in primiparous cows at first parturition, to contrast the differences in coagulase-positive staphylococcal IMI in primiparous cows at parturition in herds with high and low prevalences of coagulase-positive staphylococcal IMI in the lactating herd, and to determine the percentage of primiparous cows having persistent coagulase-positive staphylococcal IMI. Milk samples were collected aseptically from cows at the start and end of the study, at dry-off, and at parturition. Herds (n = 18) were split evenly into two categories: high (> 10%) or low (< 5%) prevalence of coagulase-positive staphylococcal IMI. At the start, the mean prevalence of coagulase-positive staphylococcal IMI in high prevalence herds was 30%, ranging from 13 to 65%, and in low prevalence herds was 2%, ranging from 0 to 5%. Overall the prevalence of coagulase-positive staphylococcal IMI in primiparous cows at parturition was 8.1% (67 of 828), ranging from 0 to 27%. Although primiparous cows from high prevalence herds had a higher prevalence of coagulase-positive staphylococcal IMI (9.2%; 40 of 436) at parturition than did primiparous cows from low herds (6.9%; 27 of 392), the difference was not significant. Of primiparous cows with coagulase-positive staphylococcal IMI at parturition, 43% had coagulase-positive staphylococcal IMI at least 2 mo after parturition. Primiparous cows with coagulase-positive staphylococcal IMI at parturition may represent significant reservoirs of infection to uninfected herdmates.

Animals↗

PubMed1994

Evaluation of the hydrometer for testing immunoglobulin G1 concentrations in Holstein colostrum.

Hydrometer measurement in globulin and IgG1 concentration measured by the radial immunodiffusion technique were compared for 915 samples of first milking colostrum from Holstein cows. Least squares analysis of the relationship between hydrometer measurement and IgG1 concentration was improved by log transformation of IgG1 concentration and resulted in a significant linear relationship between hydrometer measurement and log10 IgG1 concentration; r2 = .469. At 50 mg of globulin/ml of colostrum, the recommended hydrometer cutoff point for colostrum selection, the sensitivity of the hydrometer as a test of IgG1 concentration in Holstein colostrum was 26%, and the negative predictive value was 67%. The negative predictive value and sensitivity of the hydrometer as a test of IgG1 in Holstein colostrum was improved, and the cost of misclassification of colostrum was minimized, when the cutoff point for colostrum selection was increased above the recommended 50 mg/ml.

Animals↗

PubMed1994

Regulation of colostrum formation in beef and dairy cows.

Fifteen beef cows and 13 dairy cows were used to investigate the physiological basis of breed differences in IgG1 concentration in colostrum. Concentrations of progesterone and alpha-LA in sera and IgG1 in sera and secretion were quantified in samples collected prepartum. Serum progesterone concentration decreased significantly between 30 and 10 d prepartum, but breeds did not differ. Serum alpha-LA concentration was initially low but increased to 150 ng/ml in beef cows and 720 ng/ml in dairy cows at parturition. Serum IgG1 concentrations averaged 8.4 in beef cows and 5.7 mg/ml in dairy cows between 28 d and 24 d prepartum and subsequently declined to 6.7 in beef and 1.4 mg/ml in dairy cows between 4 d prepartum and calving. Overall, IgG1 concentration was greater in secretion from beef cows (113.4 mg/ml) than from dairy cows (42.7 mg/ml). The greater disappearance of IgG1 from serum suggested that more IgG1 was transferred into secretion of dairy cows, but concentration in secretion was lower. The reduced IgG1 concentration in secretion was associated with greater lactogenic activity in dairy cows, evidenced by fivefold higher alpha-LA concentration in sera. Dilution of IgG1 in secretion may be responsible for breed differences in colostral IgG1 concentration.

Animals↗

PubMed1994

Ecology of Staphylococcus aureus isolated from various sites on dairy farms.

The purposes of this study were to identify sources of Staphylococcus aureus on dairies and to determine whether S. aureus colonization of heifer body sites increases the risk of S. aureus IMI at parturition. In herds with high (> 10%) or low (< 3%) prevalence of S. aureus IMI, S. aureus was isolated from heifer teat skin, heifer external orifices, housing, feedstuffs, humans, nonbovine animals, air, and equipment. Additionally, in herds with high prevalence, S. aureus was isolated from bedding, insects, and water. The predominant sources of S. aureus for both groups were other IMI and heifer body sites. Heifers with prepartum lacteal secretions with S. aureus were at greater risk of S. aureus IMI at parturition than were prepartum heifers with lacteal secretions that were negative for S. aureus. Heifers with teat skin colonized by S. aureus were 3.34 times more likely to have S. aureus IMI at parturition than were noncolonized heifers. Overall, 35% of 700 heifers were colonized with S. aureus on a body site at least once. Although colonizations of most body sites appeared to be transient, a few heifers were colonized on the same site for 1 yr. Persistently colonized heifers may represent the primary reservoirs of S. aureus for other heifers.

Animals↗

PubMed1994

Effects of unilateral prepartum milking on concentrations of immunoglobulin G1 and prolactin in colostrum.

Concentration of IgG1 in colostrum of Holstein cows is often low at calving. Unilateral prepartum milking was applied twice daily beginning 10 d prepartum to seven dry cows to determine whether premature lactogenesis caused cessation of IgG1 transfer into secretion. All four quarters were milked twice daily for 3 d postpartum. Samples of blood sera and mammary secretion were collected at each milking and analyzed for IgG1, progesterone, and prolactin. Four cows that produced > 4 L/d of milk by 4 d prepartum were retrospectively designated as responders. Three cows produced less and were designated as nonresponders. Milk volume was greater for responders than nonresponders from 6 d prepartum through parturition. Concentrations of prolactin and IgG1 in secretion were lower for responders than nonresponders and for milked than unmilked sides by 6 d prepartum. For responders, cumulative secretions of IgG1, milk, and prolactin were higher for milked than unmilked sides. For non-responders, the trend was similar, but differences were not significant. Cumulative secretion of IgG1 was higher for nonresponders. Differences between sides indicate that local control is important to the regulation of colostrogenesis. Differences in IgG1 between response groups indicate that maintenance of transport and dilution are important determinants of IgG1 concentration in colostrum.

Animals↗

PubMed1993

Concentrations of passively acquired IgG1 antibodies in the intestinal lumen of the neonatal calf.

Passively acquired specific antibodies in the intestinal lumen are thought to provide protective immunity against infections with rotaviruses and other enteropathogens. In this study, concentrations of functional antibody in the intestinal lumen derived from diet and circulation were measured using 2,4-dinitrophenol (DNP) specific antibody of the IgG1 isotype, radiolabelled with 125I. The labelled IgG1 antibody was administered to neonatal calves either orally in the daily milk diet for three consecutive days (Group 1), or by a single intravenous injection (Group 2). After equilibration, the concentrations of protein-bound 125I and the specific DNP binding activities of the labelled protein in the intestinal lumen were measured, and intestinal concentrations of functional IgG1 were estimated. In Group 1 calves, protein bound 125I concentrations in the pooled small intestinal contents at 2 and 12 h after a milk meal were 50.8 +/- 20.5% and 7.9 +/- 3.4%, respectively, of the milk concentration. Protein bound 125I concentrations in the small intestinal contents were 0.7 +/- 0.4% (mean +/- SD) of serum concentrations of Group 2 calves, and were similar at 2 and 12 h after a milk meal. For a calf with average serum passive IgG1 concentrations drinking milk with normal IgG1 content, these results predict IgG1 concentrations in the small intestinal contents of milk fed calves at 2 h after a milk meal to be 0.6 mg ml-1, half of which originates from the milk and half from the circulation. At 12 h after a milk meal, intestinal IgG1 concentrations fall to approximately 0.3 mg ml-1, most of which originates from the circulation. Antibody in the intestinal lumen originating from serum retained more antigen (DNP) binding affinity than that ingested in the milk diet. Therefore, both dietary and circulating IgG1 contribute significantly to passive IgG1 antibody concentrations in the small intestinal lumen of neonatal calves, but milk derived IgG1 antibody concentrations in the small intestinal lumen were not maintained between twice daily feedings.

Abomasum↗

PubMed1993

Effect of bovine serum albumin on passive transfer of immunoglobulin G1 to newborn calves.

The molecular mechanism in the intestine of newborn calves that results in transfer of intact colostral immunoglobulin from the lumen to the circulation also is capable of transferring a variety of non-immunoglobulin macromolecules. If the capacity of this mechanism is limited, transfer of a large amount of non-immunoglobulin protein may interfere with transfer of immunoglobulin. In this experiment, efficiency of IgG1 transfer in newborn calves was reduced from 59 to 36% by the addition of bovine serum albumin (37 mg ml-1) to colostral whey, while the addition of a similar mass of amino acids in the form of acid hydrolyzed casein (37 mg ml-1) did not detectably alter IgG1 transfer. Reduced IgG1 absorption efficiency in calves fed colostrum with added bovine serum albumin is consistent with a limited capacity for the macromolecular transport mechanism in the intestine of newborn calves.

Animals↗

PubMed1993

A comparison of human and bovine Escherichia coli O157:H7 isolates by toxin genotype, plasmid profile, and bacteriophage lambda-restriction fragment length polymorphism profile.

Foods of bovine origin have been linked to human disease outbreaks caused by Escherichia coli O157:H7 and may be linked to the more common sporadic cases as well. In this study, E. coli O157:H7 from the bovine reservoir (22 isolates: 12 from dairy and 10 from beef breed cows) and from human patients (50 isolates from sporadic human infections) were compared using Shiga-like toxin genotypes, plasmid profiles, and DNA restriction fragment length polymorphisms identified with a bacteriophage lambda probe (lambda-RFLP). Twenty-three lambda-RFLP profiles, 4 Shiga-like toxin genotypes, and 8 plasmid profiles were identified among the isolates tested. Together the typing methods distinguished 43 strains, of which 3 were isolated from both humans (5 isolates) and cattle (6 isolates; 5 from dairy herds). These data demonstrate the value of lambda-RFLP as a means of strain identification for E. coli O157:H7.

Animals↗

PubMed1993

Specific antibody to Haemophilus somnus in the bovine uterus following intramuscular immunization.

Sources of anti-Haemophilus somnus antibody in bovine uterine secretions following intramuscular immunization and subsequent intrauterine inoculation of killed H. somnus were investigated. Holstein cattle (n = 21) were immunized with a 270-kDa outer membrane protein from H. somnus (omp-270) by intramuscular injection. At estrus, the cattle were given an intrauterine inoculum of a heat-killed suspension of a homologous strain of H. somnus containing omp-270 (n = 7), a heterologous strain of H. somnus lacking omp-270 (n = 7), or phosphate-buffered saline (n = 7). Uterine secretions were sampled by saline lavage immediately prior to inoculation and at 6, 24, 48, 72, 96, and 120 h after inoculation. Immunoglobulin G subclass I (IgG1) and IgG2 antibody specific for omp-270 were detectable in estrous uterine secretions of all systemically immunized cattle from which an adequate sample was obtained. IgM antibody specific for omp-270 was detected in serum following immunization but was not consistently detected in the uterine secretions of any animal. IgA antibody specific for omp-270 was not detectable in either serum or uterine secretions following immunization or intrauterine inoculation. Ratios of antibody to immunoglobulin and ratios of immunoglobulin to albumin in serum and uterine secretions indicated that about half the IgG1 and essentially all the IgG2 in secretions originated in the serum. Relative titers of IgG1 and IgG2 omp-270-specific antibodies in the uterine lumen and serum gave no evidence for selective transport of either subclass from serum into local secretions. Neither heterologous nor homologous intrauterine inocula detectably altered the serum contribution to antibody in uterine secretions within the sampling period. On the basis of these results, development of a systemic IgG2 antibody response may provide the basis for local immunological protection in the bovine reproductive tract.

Animals↗

PubMed1993

Abnormal fibrillin metabolism in bovine Marfan syndrome.

Bovine Marfan syndrome is a disorder that closely resembles human Marfan syndrome in its clinical signs and pathological lesions. The similarities between the human and bovine diseases suggest that similar metabolic defects could be responsible. Although indirect immunofluorescent assays for fibrillin in skin biopsies did not distinguish affected cattle from control animals, cultures of skin fibroblasts of affected animals were distinguished from normal, unrelated control animals and normal half-siblings on the basis of fibrillin staining. After 72 to 96 hours in culture, stained with anti-fibrillin monoclonal antibody 201, hyperconfluent fibroblast cultures of affected cattle had less immunoreactive fibrillin than control cultures, and the staining pattern was granular rather than fibrillar. Under similar culture conditions, normal bovine aortic smooth muscle cells produced large amounts of immunoreactive fibrillin, but smooth muscle cells from a single affected cow showed markedly less fibrillin staining. In pulse-chase metabolic labeling experiments with [35S]cysteine, dermal fibroblasts from 6 affected calves, incorporated far less fibrillin into the extracellular matrix than control cells. These findings are similar to those reported in human Marfan syndrome, and they suggest that the bovine Marfan syndrome, like the human disorder, is caused by a mutation in fibrillin, leading to defective microfibrillar synthesis.

Animals↗

PubMed1992

Ventricular septal defects in bovine twins.

Ventricular septal defects were diagnosed in twin cows. One of the cows was slaughtered, and the other died of complications associated with the defect. This and other reports may provide evidence to determine the basis of ventricular septal defects in cattle.

Animals↗

PubMed1992

Normal elastin content of aorta in bovine Marfan syndrome.

Samples from the ascending aortae from two calves affected by bovine Marfan syndrome were subjected to biochemical analyses of the connective tissue and were compared to age-matched controls. Elastin was extracted from the aortic samples with 5 M guanidine-HCl, bacterial collagenase digestion, and dithiothreitol reduction. Amino acid analysis revealed that desmosine and isodesmosine levels were the same in Marfan calves as in control animals. Gravimetric measurements of elastin, amino acid composition, soluble protein, and uronic acid values also showed no significant difference between Marfan and control tissue. In contrast to elastin, collagen in aortae of Marfan calves was significantly higher than the mean of several controls. These findings, along with other observations of this animal model, support the conclusion that the microscopic and biochemical lesions of aortic elastin in bovine Marfan syndrome likely result from defective microfibrillar metabolism. Absence of cystic medial necrosis in bovine Marfan aortae may explain normal elastin content in the animal model.

Animals↗

PubMed1992

Evaluation of methods for differentiation of coagulase-positive staphylococci.

The purpose of this study was to determine the minimum number of tests that could be used to differentiate between the coagulase-positive strains of staphylococcus: Staphylococcus aureus, Staphylococcus hyicus, and Staphylococcus intermedius. Eighty coagulase-positive strains of each of the three species were examined. The five tests conducted were growth on modified Baird-Parker agar, growth on P agar supplemented with acriflavin, production of acetoin, anaerobic fermentation of mannitol, and presence of beta-galactosidase. Positive test percentages for S. aureus were 100% for growth on modified Baird-Parker agar, 100% for growth on P agar supplemented with acriflavin, 94% for production of acetoin, 99% for anaerobic fermentation of mannitol, and 0% for presence of beta-galactosidase. Positive test percentages for S. intermedius were 0% for growth on modified Baird-Parker agar, 0% for growth on P agar supplemented with acriflavin, 1% for production of acetoin, 0% for anaerobic fermentation of mannitol, and 100% for presence of beta-galactosidase. S. hyicus isolates were negative in all five tests. Results from the 240 coagulase-positive staphylococcus strains tested would suggest correct identification of coagulase-positive staphylococci with P agar supplemented with acriflavin and the beta-galactosidase test. These two tests are simple to conduct and result in quick and easy differentiation of the three coagulase-positive staphylococcal species.

Animals↗

PubMed1992

Evaluation of colostral IgG1 absorption in newborn calves after treatment with alkalinizing agents.

The effects of alkalinizing agents, administered prior to feeding colostrum, on blood-gas and acid-base values and on absorption of IgG1 were determined in 40 newborn Holstein calves. Two treatments, sodium bicarbonate (3 mEq/kg of body weight, IV) and doxapram HCl (2 mg/kg, IV), were evaluated, using a randomized complete-block experimental design. These treatments resulted in significant (P less than 0.01) alteration of blood-gas and acid-base values, generally in the direction of normal values for adult cattle. Significant least squares mean effects were detected for sodium bicarbonate treatment on blood pH (+ 0.04 units, P less than 0.01), PCO2 (+ 4.1 mm of Hg, P less than 0.01), and HCO3 concentration (+ 4.4 mEq/L, P less than 0.01). Significant least squares mean effects were detected for doxapram HCl treatment on blood pH (+ 0.06 pH units, P less than 0.01) and PCO2 (-5.2 mm of Hg, P less than 0.01). Absorption of colostral IgG1 was not affected by the treatments given or by the altered blood-gas and/or acid-base status.

Absorption↗

PubMed1991

Comparison of three methods of feeding colostrum to dairy calves.

Absorption of colostral immunoglobulins by Holstein calves was studied in 3 herds in which 3 methods of colostrum feeding were used. Failure of passive transfer, as determined by calf serum immunoglobulin G1 (IgG1) concentration less than 10 mg/ml at 48 hours of age, was diagnosed in 61.4% of calves from a dairy in which calves were nursed by their dams, 19.3% of calves from a dairy using nipple-bottle feeding, and 10.8% of calves from a dairy using tube feeding. The management factor determined to have the greatest influence on the probability of failure of passive transfer in the herds using artificial methods of colostrum feeding (bottle feeding or tube feeding) was the volume of colostrum fed as it affected the amount of IgG1 received by the calf. In dairies that used artificial feeding methods, failure of passive transfer was infrequent in calves fed greater than or equal to 100 g IgG1 in the first colostrum feeding. In the dairy that allowed calves to suckle, prevalence of failure of passive transfer was greater than 50% even among calves nursed by cows with above-average colostral IgG1 concentration. Analysis of the effect of other management factors on calf immunoglobulin absorption revealed small negative effects associated with the use of previously frozen colostrum and the use of colostrum from cows with long nonlactating intervals.

Animals↗

PubMed1991

Management and production factors influencing immunoglobulin G1 concentration in colostrum from Holstein cows.

Immunoglobulin G1 concentration was measured in 919 first milking colostrums from Holstein cows during a 4-yr period on a commercial dairy farm. Sources of variation analyzed for effect on colostral IgG1 concentration were season of calving, lactation number, dry period length, intercalving interval, complete lactation milk and fat production, weight of first milking colostrum, and time from calving to first milking. Weight of first milking colostrum was the variable most highly correlated (negatively) with colostral IgG1 concentration (r = -.29). Weight of first milking colostrum and lactation number of the cow were the most significant discriminators between colostrum of low and high IgG1 concentration. The implications of these results for colostrum feeding management are discussed.

Animals↗