摘要:

Bovine mammary gland mononuclear cells (MGMC) and peripheral blood mononuclear cells (PBMC) were isolated during the non‐lactating period to determine if recombinant bovine somatotropin (rbST) enhanced mitogen‐stimulated mononuclear cell proliferation and/or overcame suppressive effects of mammary secretions on mononuclear cell proliferation in vitro. MGMC were hyporesponsive to mitogenic stimulation compared with PBMC. Mammary secretions markedly suppressed the MGMC and PBMC response to mitogens. rbST had no effect on mononuclear cell proliferation in the presence or absence of mitogens. Similarly, rbST did not reverse the suppression of mononuclear cell proliferation by mammary secretions. Under the conditions of this study, rbST had no direct effect on the proliferation of mature bovine mononuclear cells.

ISSN:0954-0105    

DOI:10.1080/09540109209354769

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A multi‐residue screening test was developed which provides reliable detection of eight ß‐agonists in urine, based on an enzyme immunoassay with peroxidase and an antibody raised against clenbuterol‐diazo‐BSA. Antibodies were compared after continuous immunization. The antibody obtained after the 12th immunization showed the best sensitivity, procedural blanks of urine samples and coefficients of variation, using analysis of spiked urine samples. The simultaneous clean‐up was performed with silicagel RP select‐B. In 125 samples from untreated female or male cattle or pigs, sample blanks gave results of <0·07 ng clenbuterol equivalents/ml urine and in two further samples, results of 0·13 and 0·15 ng/ml, respectively. The method showed coefficients of variation of 20–30% for the ß‐agonists tested, except in the case of orciprenaline, at levels ranging from 0·1 ng/ml urine (clenbuterol, mabuterol) to 10 ng/ml urine (pirbuterol, orciprenaline). These ß‐agonists were also separated by a high performance liquid chromatography (HPLC) system, which provided complete separation of orciprenaline, 2‐amino‐3‐chloro‐5‐(1'‐hydroxy‐2'amino‐tert‐butyl‐ethyl) pyridine (ACP), isoetharine, clenbuterol and mabuterol as well as good separation of carbuterol, terbutaline, salbutamol and pirbuterol.

ISSN:0954-0105    

DOI:10.1080/09540109209354770

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Polyclonal antibodies against sulfamethazine, sulfadiazine, sulfamethoxypyridazine and trimethoprim were prepared by using bovine serum albumin conjugates of the respective substances as antigens for the immunization of rabbits. The specificity and sensitivity of these antibodies were tested by using the respective drug coupled to horseradish peroxidase as the labelled antigen in a competitive assay. The antiserum against sulfamethazine showed relative cross‐reactivities of 100 and 56% with sulfamethazine and sulfamerazine, respectively. The antiserum against sulfadiazine showed relative cross‐reactivities of 100, 12, 11 and 10% with sulfadiazine, sulfasalazine, sulfamerazine and sulfathiazole, respectively. The assays for sulfamethoxypyridazine and trimethoprim showed no relative cross‐reactivity above 1%. The detection limits (in buffer solution) for sulfadiazine, sulfamethazine, sulfamethoxypyridazine and trimethoprim were at 1.1, 1.3, 2.8 and 6.0 ng/ml, respectively. The recovery of the sulfonamides from milk samples, artificially contaminated at levels of 5, 10, 50 and 100 ppb, was between 68 and 99%. Recovery of trimethoprim from artificially contaminated milk samples was about 90% at concentrations of 50 and 100 ppb.

ISSN:0954-0105    

DOI:10.1080/09540109209354771

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Rabbit anti‐native bovine ß‐casein antiserum reacted with native ß‐casein and fragments f( 1–105/7) and f( 106–209) formed during ß‐casein proteolysis by plasmin. Agglutination of ß‐casein‐coated microparticles by anti‐native ß‐casein antiserum was weakly inhibited by ß‐casein f(1–105/7) and ß‐casein f( 106–209) (0·04 and 1·4%, respectively, compared with native ß‐casein). Immunoreactivity of these ß‐casein peptides in microparticle‐enhanced nephelometric immunoassay was more preserved in the whole ß‐casein than in its isolated fragments. The protein concentration producing 50% inhibition of the ß‐casein‐coated microparticle agglutination with anti‐native ß‐casein antiserum increased during ß‐casein denaturation. A microparticle‐enhanced nephelometric immunoassay, quantifying changes of this inhibiting protein concentration, permitted detection of alteration of the immunoreactivity of ß‐casein during its plasmin proteolysis and heat denaturation, providing an adequate test for the integrity of the whole molecule.

ISSN:0954-0105    

DOI:10.1080/09540109209354772

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Antigenic extracellular polysaccharides (EPS) were produced by Penicillium digitatum and P. aurantiogriseum under various conditions, including different carbon and nitrogen sources, glucose concentrations and incubation periods. With lactate as carbon source no antigenic EPS was produced. EPS consisted mainly of glucose, mannose and galactose. Differences were seen in the monosaccharide composition. The amount of glucose in the medium (1–30 g/l) influenced growth and the production of antigenic EPS moderately. The antigenicity of P. aurantiogriseum EPS, but not that of P. digitatum, decreased with prolonged incubation. P. aurantiogriseum, but not P. digitatum, grew well with nitrate as the nitrogen source.

ISSN:0954-0105    

DOI:10.1080/09540109209354773

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Whey proteins from non‐lactating bovine mammary secretions reduced peripheral blood mononuclear cell (PBMC) response to mitogens. Specific proteins responsible for hyporesponsiveness are unknown. This study evaluated the influence of apo‐ and ironsaturated lactoferrin (APOLF and FELF) and transferrin (APOTF and FETF), immunoglobulin G (IgG) and serum albumin (SA) at concentrations ranging from 0·02 to 2·5 mg ml‐1on PBMC response to concanavalin A. PBMC were collected from five pregnant Holstein cows during late lactation. Lactoferrin (LF), transferrin (TF) and IgG resulted in a dose‐dependent reduction of PBMC proliferation, whereas SA had no effect. Decreased PBMC response was significant at all concentrations of APOLF and FELF, at APOTF concentrations ≥ 0.3 mg ml‐1, only at 2·5 mg ml‐1FETF, and at IgG concentrations ≥ 1·25 mg ml‐1. The degree of iron saturation of LF did not influence PBMC response; however, APOTF had a greater influence than FETF. Reduced PBMC response at low levels of LF indicate that hyporesponsiveness is not due solely to an increased protein content of the culture but may be the result of specific LF regulation of mononuclear cell proliferation.

ISSN:0954-0105    

DOI:10.1080/09540109209354774

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Food Safety and Quality Assurance: applications of immunoassay systems M. R. A. MORGAN, C. J. SMITH & P. A. WILLIAMS (Eds), 1992 Elsevier Applied Science, London and New York 496 pp.

ISSN:0954-0105    

DOI:10.1080/09540109209354775

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109209354776

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109209354768

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor