New safety assurance for biological skin covers.

The described system of safety assurance of cryopreserved allogeneic and xenogeneic dermoepidermal transplants comprises serological examination of deceased tissue donors, long-term storage of sera of all donors, microbiological control of prepared allogeneic and xenogeneic dermoepidermal grafts, labelling of released tissue grafts and monitoring of temperatures inside the mechanical freezer (-80 degrees C). From a total number of 76 donors from whom tissues were collected for transplantation during 1999-2001, tissues were discarded in two instances. One because of a positive HBsAg test, the others second one because of presence of anti-HTLV antibodies. In xenogeneic dermoepidermal grafts, out of a total number of 1,203 grafts prepared during the same period, 84 (6.9%) were discarded because of the presence of pathogeneic or potentially pathogeneic microbes. The system of labelling released grafts makes unequivocal identification of the pathway from recipient to donor possible, while at the same time respecting the anonymous character of the donor's data. In xenogeneic grafts it ensures the identification of the appropriate batch. Storage of cryopreserved biological skin covers at a temperature of -80 degrees C in low temperature cabinets with emergency back-up cooling with liquid nitrogen and a supplementary source of electric power, proved very useful. The system responds to the gradual implementation of the principles of Quality Management System ISO 9000 and Good Manufacturing Practice into the activities of tissue banks. Further tightening of the demands for the safety of allo- and xeno-transplantation is foreseen in conjunction with the occurrence of transmissible spongiform encephalopathy and porcine retroviruses.

Biological skin covers in treatment of two cases of the Lyell's syndrome.

The treatment of two cases of toxic epidermal necrolysis (Lyell's syndrome) is described. Although some features were common for both ones (young men practically of the same age, reaction after using the same drug) the clinical course of illness was very different. Spontaneous epithelisation of partial-thickness lesions and definitive healing under the xenografts in one patient and full-thickness skin-loss on 12% of body surface with severe septic complications requiring application of cultured keratinocytes and/or skin autografting in the other patient were the main differences. The interdisciplinary approach using a burns treatment protocol in non-burned patient including the close co-operation with the tissue bank in preparing different types of biological covers has been applied.

Immunoradiometric and luminescence immunoenzymometric assay of human thyrotropin from dried blood spots for screening of neonatal hypothyroidism.

Two monoclonal antibodies to thyrotropin prepared in our laboratory were employed for the development of two-site immunometric assays in two modifications for the estimation of human thyrotropin in dried blood spots designed for the screening of neonatal hypothyroidism. The immunoradiometric assay using the second antibody labelled with 125I is simple and fast (one incubation step lasting 2 h). The detection limit of 1 mU/l and the absence of the hook effect up to a concentration of more than 1000 mU/l are optimal for neonatal screening; the presence of other glycoprotein hormones does not interfere with the assay. In the luminescence immunoenzymometric assay the second antibody is labelled with peroxidase. In spite of the two-step configuration the method is fast (4.5 h) and enables specific determination of thyrotropin levels in the range of 2.4-1100 mU/l. The conditions and properties of both immunometric assays described are comparable with the time-resolved immunofluorometric assay widely used in Europe.

[Inhibition of Candida albicans transformation from the yeast form to the mycelial form by 2-alkylthio-6-amino- and 2-alkylthio-6-formamido- benzothiazoles]. / Inhibícia transformácie kvasinkovitej formy Candida albicans na mycéliovú formu 2-alkyltio-6-amino- a 2-alkyltio-6-formamidobenzotiazolmi.

The inhibitory effectiveness of 2-alkylthio-6-amino- and 2-alkylthio-6-formamidobenzothiazoles (19 derivatives altogether) on the transformation of the yeast-like form of Candida albicans into the mycelial form (1 strain from the collection and 2 clinical isolates) was investigated. Most derivatives tested, similarly as the standard 2-mercaptobenzothiazole (Dermacid), did not exert any difference between the inhibitory effectiveness on filamentation and the inhibition of the growth and reproduction of the yeast-like form. However, the best derivative, 6-amino-2-n-pentylthiobenzothiazole, showed as much as 25-fold higher inhibitory effectiveness on the transformation of the yeast-like form into the mycelial one than MIC.