Variation of counting efficiency in determination of 131I activity in the thyroid gland as a result of its position relative to the detector.

The appropriate determination of the 131I which was absorbed into the human body, especially by thyroid, depends not only on individual features of each measurement subjects but also on reproducibility of their position or the thyroid's position in the human neck. Possible uncertainties caused by changes of the thyroid position relative to detector were studied in a series of measurements. The research has shown that the dispersion of the results can reach up even to the level of 50 %.

First report of Schmallenberg virus infection in cattle and midges in Poland.

Two outbreaks of Schmallenberg virus (SBV) infection that coincided with the introduction of two bulls imported from France into two herds located in West Pomerania and Silesia provinces in Poland are described in detail. The first SBV real-time RT-PCR-positive result was obtained during routine testing of one of the imported bulls. The second bull and the affected farms were tracked by further investigation. Transmission of SBV into Polish cattle herds where the bulls were imported was confirmed by viral RNA detection in real-time RT-PCR, virus isolation followed by immunoperoxidase (IPX) staining and seroconversion. SBV RNA was detected also in Culicoides obsoletus pools caught in a trap located 5 km from one of the outbreaks. Testing nearly 900 samples collected prior to the two outbreaks from the same areas or provinces neighbouring with Germany where SBV cases had previously been detected gave negative results for the presence of SBV or specific antibodies. These cases are the first ones detected in cattle in Poland and provide evidence of recent transmission of the pathogen into the country and involvement of midge vectors.

Two patterns of NK activity changes following blood donation: decrease in the beginners and restoration in regular blood bank donors.

NK cell activity of peripheral blood lymphocytes was determined in voluntary blood bank donors in a standard 4-hr 51Cr-release cytotoxicity assay. When blood donors were divided into groups according to the total amount of blood they had donated in the past, decreased NK activity was found in "moderate" donors who had donated between 3 and 9 l of blood, but not in those who had donated < or = 3 or more than 9 l of blood before testing. This observation was the rationale for a study on the effects of regular blood donations on NK activity in randomly selected voluntary blood bank donors re-tested over a period of time. The study demonstrated decreased NK activity in the second measurement in donors who had donated up to 6 l of blood before the study, and an increase in NK activity between the first and the second testing in those who had donated more than 6 l of blood. This result, together with data obtained at the population level, suggests that some compensatory mechanism(s) regulate NK activity in the course of regular blood donation.

Opposite effect of donor-specific immunization by blood or splenocytes on the survival of heart tissue transplants in strong versus weak histoincompatible combination in mice.

Recipients of allogeneic heart tissue were pretreated intravenously with blood or injected intraperitoneally with spleen cells. In H-2 incompatible donor-recipient combination (BALB/c----CBA/H) donor-specific immunization, both with blood and spleen cells, resulted in acceleration of graft rejection. On the other hand, increase in graft survival was observed following donor-specific but not third-party blood pretreatment in mice compatible in H-2 complex but bearing different minor histoincompatible antigens (BALB/c----DBA/2).

The influence of blood withdrawal on NK activity in mice.

Natural killer (NK) cell activity was analyzed both in peripheral blood and spleen in mice following a single and repeated blood withdrawal from tail vein. No statistically significant changes of activity of NK cells in consequence of either single or multiple bleedings was observed. The schedule of bleeding used in this study does not seem to influence an absolute count in blood and spleen cellularity, either.

Chromatographic degradation of phloridzin.

Phloridzin, the main phenolic glucoside in apple leaves, has been found to undergo transformation during chromatography. When chromatographed repeatedly in ammoniacal solvents, at least 2 new derivatives appeared. One of these was identified as phloretic acid. When bioassayed in the presence of indole-3-acetic acid this substance behaved as though it promoted the destruction of the auxin. Comparative bioassay with naphthaleneacetic acid suggested that phloretic acid acts on indoleacetic acid destruction via stimulation of indoleacetic acid oxidase. However, at low concentration and in presence of a small amount of phloridzin it also showed a synergistic effect with indoleacetic acid.A substance with the same characteristics was obtained directly from apple leaves, which are known to contain phloridzin when the extracts were chromatographed only once in the same (alkaline) solvent. While not completely confirmed, this suggests that phloretic acid is normally present in apple leaves, where it may affect growth there by promoting indoleacetic acid oxidation.