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C F Hendriksen

Publications and source records attributed to C F Hendriksen.

33 records · Page 2Linked to original sources
PubMed1994

Immunogenicity testing of diphtheria and tetanus vaccines by using isogenic mice with possible implications for potency testing.

The antitoxin response of isogenic mice (inbred strains and F1 hybrids), immunized with diphtheria and tetanus reference vaccines, was compared with the response of animals from an NIH outbred stock. The variance in antitoxin response was smaller within the groups of isogenic mice than within the group of mice from the outbred strain. The case for estimating the potency of diphtheria and tetanus vaccines by using isogenic mice is discussed. It is concluded that the general introduction of one common inbred strain or F1 hybrid selected on the basis of sensitivity would increase the comparability of data between laboratories and would enable an estimated reduction in the use of animals of about 35% or an improvement in the precision of the estimate of potency.

Animals↗
PubMed1991

The use of the in vitro toxin binding inhibition (ToBI) test for the estimation of the potency of tetanus toxoid.

The in vitro toxin binding inhibition (ToBI) test was used to determine antitoxin responses in mice immunized with tetanus toxoid. The ToBI test showed good correlation with the in vivo toxin neutralization (TN) test in titration of sera of mice immunized with various doses of DPT-Polio, DT-Polio and a tetanus reference preparation. Estimates of potency of tetanus toxoid obtained in mice by ToBI test correlated significantly with those obtained in mice by the lethal challenge test. In addition, potency values of the European reference preparation, succeedingly estimated by ToBI test and lethal challenge test in a single group of guinea-pigs, showed good correlation. From the study it is concluded that the ToBI test is a promising alternative to the toxic challenge procedure in the potency assay of tetanus toxoid vaccines. A substantial refinement and reduction in the use of animals can be achieved. Additional savings can be made by combining diphtheria and tetanus potency testing.

Animal Testing Alternatives↗
PubMed1989

Combined estimation of tetanus and diphtheria antitoxin in human sera by the in vitro Toxin-Binding Inhibition (ToBI) test.

The use of the principle of inhibition of toxin binding to an antitoxin coated immunoassay plate as described in a previous paper for tetanus antitoxin titration, was adapted for the estimation of diphtheria antitoxin in human sera. With a few modifications, a Toxin-Binding Inhibition (ToBI) test was developed which could be used for a combined estimation of both tetanus and diphtheria antitoxin levels. The application of streptavidin-biotinylated peroxidase complex when using small serum samples (less than 50 microliters) is discussed. Antitoxin titres (both diphtheria and tetanus) of 0.002 IU ml-1 were detectable by the ToBI test, this being far below the level considered to be protective in man. Sera from 140 adults with different vaccination histories were titrated for both tetanus and diphtheria antitoxin. Good correlations were found between the estimates obtained by the ToBI test and those obtained by the toxin-neutralization (TN) test in mice (tetanus antitoxin) and those obtained in the in vitro neutralization test in VERO cells (diphtheria antitoxin). It is concluded that the ToBI test is a simple and reliable alternative to the functional models currently in use for the estimation of diphtheria and tetanus antitoxin levels. In addition, the ToBI test eliminates the need for laboratory-animal or cell-culture facilities and can be performed with small quantities of serum as required in field trials.

Animals↗
PubMed1989

The use of the Toxin Binding Inhibition (ToBI) test for the estimation of the potency of the diphtheria component of vaccines.

The Toxin Binding Inhibition (ToBI) test, previously developed for the estimation of diphtheria and tetanus antitoxin in human sera, was adapted for the estimation of the potency of diphtheria components in vaccines. Data are presented to show that antitoxin titres of individual sera of mice obtained by the ToBI test are in good agreement with those obtained in the Vero cell test. In addition, diphtheria potency and 95% confidence interval of twelve batches of vaccine in different compositions were estimated by the ToBI test and the results were compared with those obtained in Vero cells. A significant correlation could be demonstrated. It is concluded from this study that the ToBI test is a valuable model in the potency assay of diphtheria toxoids, based on antitoxin induction in mice.

Animals↗
PubMed1988

The toxin binding inhibition test as a reliable in vitro alternative to the toxin neutralization test in mice for the estimation of tetanus antitoxin in human sera.

A method for the screening of human sera for tetanus antibodies has been developed and evaluated. The toxin binding inhibition test (ToBI-test) is based on inhibition of the binding of tetanus toxin to an antitoxin-coated immunoassay microtitre plate by tetanus antibodies. Serum samples from 191 healthy adults with different vaccination histories have been titrated for tetanus antibodies by the toxin neutralization (TN) test in mice, by toxoid-ELISA and by the ToBI-test. In every respect, the ToBI-test proved to be the best in vitro alternative to the TN-test in mice. Comparisons showed a higher degree of correlation between the ToBI-test and the TN-test than between the toxoid-ELISA and the TN-test. Furthermore, no overestimation of antibody content was seen in titrating low titre sera by the ToBI-test. In contrast, several false positive results were seen when using the toxoid-ELISA. It is concluded that the ToBI-test is a reliable and precise alternative to the TN-test and can be performed under simple laboratory conditions in a short time.

Animals↗
PubMed1987

The effects of reductions in the numbers of animals used for the potency assay of the diphtheria and tetanus components of adsorbed vaccines by the methods of the European pharmacopoeia.

Forty eight assays of adsorbed diphtheria vaccine and seven assays of adsorbed tetanus vaccine using either a lethal challenge (38 assays) or a serum neutralization test (17 assays) were evaluated for the effects of reductions in the number of animals used at each dilution on the potency values and 95% confidence intervals. The results were assessed in the light of the requirements of the European Pharmacopoeia and the WHO. In the majority of assays, 50% of the number of animals presently required would have sufficed for the determination of a potency within the limits of confidence stipulated by the European Pharmacopoeia and the WHO. Therefore it is concluded that a simplified assay with a reduced number of animals is suitable for the routine potency testing of the diphtheria and tetanus components of the combined vaccines and the monovalent that were examined. Flexibility in the national and international requirements in respect of the numbers of animals used at each dilution is suggested for the routine potency assay of the diphtheria and tetanus components of adsorbed vaccines.

Animal Welfare↗
PubMed1984

[Animal experiments and restriction of laboratory animals].

The position of animals in the community is being increasingly considered today. Interest is particularly directed to a number of controversial relations between man and animals, including experimental studies. This last-named category requires approximately 1.4 million animals annually. Experimental studies have undoubtedly contributed to the current levels of prosperity and welfare. However, there are ethical, scientific and economic reasons for advocating a policy directed towards restriction of the number of experimental animals. A policy of this type, directed to the substitution, reduction or refinement of experimental studies, should be both regulative and innovatory in character. Regulative in referring to the authorities, innovatory in referring to the development of methods of investigation which will relieve experimental animals, the so-called alternatives. The veterinarian, in his position of representative of the interest of animals, should direct a laboratory-animal-restricting policy either as a laboratory animal scientist or indirectly as a practitioner.

Animal Testing Alternatives↗
PubMed1981

Repeated exposure to alpha-ethylacrolein vapour: subacute toxicity study in rats.

The subacute inhalation toxicity of alpha-ethylacrolein was examined in rats by repeated exposure of 4 groups of 10 males and 10 females each to alpha-ethylacrolein vapour at concentrations of 0, 2.0, 9.8 or 48.4 ppm, respectively, (6 h/day, 5 days/week) for a period of 13 weeks. The effects at 48.4 ppm were found to include growth retardation, focal alopecia, increased activity of glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase and alkaline phosphatase in the blood serum, decreased concentrations of total protein and albumin in the blood serum, increased relative weight of the heart, liver, adrenals and lungs, and histopathological changes in the respiratory tract mainly consisting of hyper- and metaplasia of respiratory epithelium and atrophy of the nasal olfactory epithelium. While at the 9.8 ppm level only a few relatively minor effects were noticed, viz. decreased concentrations of total protein and albumin in the blood serum and minimal hyper- and metaplasia of the tracheobronchial epithelium, no changes attributable to alpha-ethylacrolein were observed at the 2.0 ppm level.

Acrolein↗