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J Buys

Publications and source records attributed to J Buys.

36 records · Page 2Linked to original sources
PubMed1976

Reliability of the enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Trichinella spiralis infections in conventionally raised pigs.

An enzyme innunoassay using horse radish peroxidase as teh marker enzyme for the detection of antibodies to Trichinella spiralis in pigs was described. In the enzyme-linked immunosorbent assay (ELISA) quantitation os specific antibodies is obtained by means of peroxidase labeled anti-species-immunoglobulin in antigen-coated tubes. The enzyme remaining in the tube after wasging provides a measure of the amount of specific antibodies in the serum. A crude saline extract of T. spiralis muscle larvae served as antigen. In experiments in which conventionally raised pigs intended for slaughter were infected with various numbers of T. spiralis larvae (25,000; 12,500; 5,000; 2,500; 1,500; 500; 150; 50) a positive correlation was found between initial dose of larvae administered and amount of antibodies detected by ELISA. Compared with immuno-fluorescence (IF) ELISA was more sensitive. IF yielded positive results in 11 out of 34 infected animals, whereas ELISA results were positive in 27 cases. In order to evaluate ELISA results under practical conditions extinction values os sera from both infected and non-infected conventional pigs were compared with the highest extinction value of a group of 74 negative conventional pig sera. Due to the relatively high background reaction of some of these negative sera the number of positive practical ELISA results decreased from 27 to 19 out of 34 animals. Furthermore, in 1 out of 10 non-infected animals a false positive practical ELISA result was obtained. Ways to improve the reliability of ELISA are discussed.

Animals↗
PubMed1976

Reliability of the enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Trichinella spiralis infections in conventionally raised pigs.

An enzyme immunoassay with horse radish peroxidase as marker enzyme for detection of antibodies to Trichinella spiralis in pigs is described. In the enzyme-linked immunosorbent assay (ELISA) quantitation of specific antibodies is obtained by means of peroxidase labeled anti-species-immunoglobulin in antigen-coated tubes. The enzyme remaining in the tube after washing provides a measure of the amount of specific antibodies in the serum. A crude saline extract of T. spiralis muscle larvae served as antigen, 5 mug protein/ml being a satisfactory concentration. Lyophilization of antigen had no adverse effect on sensitivity. To decrease background staining the use of an optimal conjugate dilution was important. Adding bovine serum albumen to the conjugate was essential to decrease background reactions. Suitable substrate incubation times were studied. Washing was performed with tap water and Tween 20. In experiments with conventionally raised slaughter pigs infected with different numbers of T. spiralis larvae a positive correlation was found between initial dose of larvae and amount of antibodies detected by ELISA. Compared with immunofluorescence (IF) ELISA was more sensitive. IF yielded positive results in 11 out of 34 infected animals, whereas ELISA results were positive in 27. To evaluate ELISA under practical conditions extinction values of sera from infected and non-infected conventional pigs were compared with the highest extinction value in a group of 74 negative conventional pig sera. The relatively high background reaction of some of these negative sera decreased the number of positive practical ELISA results from 27 to 19 out of 34. In 1 out of 10 non-infected animals a false positive practical ELISA result was obtained.

Animals↗
PubMed1975

Application of immunofluorescence and immunoenzyme methods in the serodiagnosis of Trichinella spiralis infection.

To detect antibodies to T. Spiralis in sera, the IF methods with the cuticle of T. spiralis larvae (the tube test) was compared to the cryostat method. In the latter method, cryostat sections were prepared from isolated T. spiralis larvae or from tongue or diaphragm musculature in which encysted T. spiralis larvae were present. In this case, both cuticle and internal structures were employed as antigenic sites. The cryostat method proved to be more sensitive than the tube test. With the cryostat method, specific antibodies were detected in sera of experimentally infected mice 14 days after infection, whereas with the tube test, antibodies were detected on Day 24 postinfection and consistently thereafter. The enzyme-linked immunosorbent assay (ELISA) was then studied. Quantitation of specific antibodies was achieved with alkaline phosphatase- or peroxidase-labeled antispecies immunoglobulin in antigen-coated tubes. The enzyme that remained in the tube after washing provided a measure of the amount of specific antibodies in the serum. A saline extract of T. spiralis larvae served as the antigen. In the experimental models studied (T. spiralis-infected rabbits and pigs), ELISA proved to be more sensitive than IF. At Day 3 postinfection and thereafter, specific antibodies could be detected. ELISA was modified to satisfy requirements for routine application.

Alkaline Phosphatase↗
PubMed1975

Studies on isolation and drug sensitivity of Trypanosoma vivax in northern Nigeria.

In a study to investigate the occurrence in cattle of Trypanosoma vivax strains resistant to the normal therapeutic dose of homidium, 47 isolates of T. vivax were collected from 10 different trypanosomiasis treatment centres in the North Central State of Nigeria. Of these 47 isolates, 23 produced infection in the experimental animals that were used for subsequent drug sensitivity trials. While all but one of the experimental cattle inoculated with T. vivax became infected, less than 50% of the experimental sheep and none of the experimental goats were able to reproduce infection. This difference in infectivity is discussed and related to the stage of the T. vivax infection in the donor cattle. None of the 23 isolates of T. vivax was resistant to homidium. The value of sheep and goats in T. vivax experiments is discussed.

Animals↗
PubMed1975

[Immunofluorescence technique in diagnosis of trichinellosis in swine. II. Comparative investigations with the tube test and the cryostate method (author's transl)].

A series of comparative IF tests have been made on serum samples from 9 SPF pigs experimentally infected with Trichinella spiralis (50-500 larvae per animal). The techniques applied included a tube test (antigen: whole Trichinella larvae), and a cryostat test (antigen: sections of Trichinella larvae). With the cryostat test a positive reaction was recorded in 2 animals already on the 6th day and in 5 animals on the 13th day p.i., while with the tube test such reaction was not demonstrated until the 27th day p.i. (2 animals). A potential risk of cross-reaction of unknown origin seems, however, to limit the application of the cryostat test to SPF- pigs.

Animals↗
PubMed1975

Mechanization of a micro complement fixation test for the serodiagnosis of human toxoplasmosis.

A description is given of a mechanized micro complement-fixation test for the serodiagnosis of human toxoplasmosis. Besides a reduction in the quantity of reagents by using a microplate a considerable advantage of the test is the mechanization of actually all steps. Examination of large numbers of sera can be realized in a relatively short period of time. In order to test the sensitivity of the micro CF test comparative studies were carried out with the macro CF test and the immunofluorescence (IF) test on 549 human sera. The micro CF test proved to be more sensitive than the macro CF test. The results obtained with the micro CF test were in better agreement with the IF test than those obtained with the macro CF test.

Autoanalysis↗
PubMedDate not supplied

Corynebacterium parvum: antibodies measured with the enzyme-linked immunosorbent assay (ELISA) in normal human sera and sera from cancer patients undergoing treatment.

An enzyme-linked immunosorbent assay (ELISA) was developed to monitor the antibody response to Corynebacterium parvum during cancer immunotherapy. Firstly, in sera from 176 clinically healthy individuals not treated with C. parvum, elevated ELISA extinction values were observed from the age of 11 years onwards for both sexes; these high values were probably due to preexisting antibodies to C. parvum or related organisms. Consequently, in order to evaluate C. parvum antibody levels after treatment it was essential to compare post- with pre-treatment sera. Next, a series of sera from 20 male patients with inoperable squamous cell carcinoma of the bronchus were tested. They originated from three different groups. The first group received both chemotherapy (cyclophosphamide) and immunotherapy (C. parvum), the second group cyclophosphamide alone and the third group neither of these agents. Compared to pre-treatment values, an increase in extinction values was already observed as from day 12 of C. parvum treatment; cyclophosphamide did not influence the extinction values. Antibody production per se did not seem to be correlated with an anti-tumour effect. The sensitivity of ELISA was similar to a previously described latex agglutination test.

Antibodies, Bacterial↗