Efficacy demonstration of tetanus vaccines by double antigen ELISA.

This paper describes a double antigen ELISA (DAE) for rapid, specific and reliable assessment of the antitetanus immune status of horses and sheep. Compared with the indirect ELISA, the double antigen ELISA has the advantage of species-independent testing of sera. Thanks to its test design, it is more specific since the detected antibodies are forced to bind tetanus toxoid twice. In addition, it is very sensitive to tetanus antibodies, enabling the detection of low antibody titres, in range which is relevant for the assessment of the protective status (tetanus toxin neutralising antibodies). The detection limit of the DAE for tetanus antibodies is in the order of 10(-4) EU/ml. A comparison of in vitro results of individual sera with in vivo titres showed that horse sera with titres of 0.04 and 0.05 EU/ml in the DAE showed titres of > 0.05 IU and 0.034 IU/ml respectively during in vivo testing thus indicating good agreement. For tested sheep sera which were rated > 0.05 IU/ml in vivo, the corresponding titre in the DAE was 0.24 EU/ml. Clear tetanus antitoxin establishment of protective ELISA limits requires further comparative examination of sera with low titres (< 1.0 EU/ml) in the double antigen ELISA and the toxin neutralisation test. With the double antigen ELISA, efficacy can be determined for marketing authorisation procedures of tetanus vaccines ad us. vet. As a consequence, the toxin neutralisation test (still being the standard method of choice for quantifying tetanus toxin neutralising antitoxin titres) could be replaced, since it requires too great a number of animals per test and involves considerable suffering for the animals. The test described here reduces the use of mice and guinea pigs within vaccine efficacy testing. In addition, it involves less exposure of the laboratory personnel to toxin.

[Endolymphatic stromal myosis, a rare semimalignant tumour (author's transl)]. / Uber die endolymphatische stromale Myose, einen seltenen semimalignen Tumor.

The rarely occurring disease of endolymphatic stromal myosis is discussed by means of an impressive case. The cells of this semimalignant tumour resemble those of the endometrium, but it is not clear whether this tumour can be derived histogenetically from the endometrium or from the cells of the duct of Müller (ductus paramesonephricus) or from pericytal cells. The histological pattern of the tumour, which is characterized by the uniformity of small spindle-like oval cells without remarkable mitotic activity, and by a lack of atypical criteria, does not permit any prognosis in respect of its clinical behaviour. According to the rare references in literature, the clinical course is usually protracted with occasional occurrence of metastases and relapses. The therapy consists of radiotherapy and administration of progesterone. The case described in this article is a clinically malignant one because of disseminated metastases and relapse following initially successful therapy.

[Heavy metal content in sediment samples taken from drinking-water reservoir (author's transl)]. / Untersuchungen über den Schwermetallgehalt im Sediment einer Trinkwassertalsperre

Sediment samples were taken from the small preliminary catchment basin of the Wahnbachtal reservoir at Siegburg, extracted under mild conditions with nitric acid and hydrogen peroxide and analysed for their content of heavy metals. The sediment sample of the most recent date showed the highest concentrations of metal, that of older date revealed lower values, but by far the lowest metal content was found in the clay of the former valley. The high metal contents in the sediment are not only to be attributed to human influence but are primarily caused by the lead and zinc ores in the catchment area. The hygienic significance of these results is to be seen in the remobilization processes which could lead to an undesirable increase of metal concentrations in the raw water fed to the drinking water treatment plant.