Comparison of manual and automatic sampling for monitoring ochratoxin A in barley grain.

Automatic and manual sampling for ochratoxin A (OTA) in barley grain was compared under industrial conditions considering sampling uncertainty as well as practical and technical aspects. Ten tonnes of barley inoculated with Penicillium verrucosum were incubated until the OTA concentration reached approximately 15 µg kg(-1) and sampled with manual and automatic sampling. A nested experimental design and ANOVA was used to estimate variance components from sampling, sample reduction, sample preparation and analysis. Manual sampling resulted in a high sampling uncertainty and OTA concentrations in aggregate samples ranged from 2 to 80 µg kg(-1). When aggregate samples were formed by automatic sampling the uncertainty arising from nugget effects and spatial distribution was practically eliminated. Results from this study show that an automatic sampler mounted after a mixer or conveyer can provide representative samples of OTA from a moving stream of barley. Automatic sampling might present a practical and economical alternative to manual sampling for feed mill operators when monitoring low levels of mycotoxins in grain or other commodities. Despite careful precautions, sample preparation and analysis resulted in a relative uncertainty of ±40% (p = 0.95), which was attributed to the sub-sampling following the two grinding steps. Size fractionation of the coarsely ground barley showed that 40% of the total amount of OTA was present in a small fraction of fine particles with a strong tendency to aggregate or stick to equipment and containers. Thus, in order to take advantage of the automatic sampling, it is crucial to apply an appropriate sub-sampling to prevent segregation of particles which may affect the OTA measurements.

[Autonomous nervous system in patients with early postmyocardial infarction angina pectoris]. / Sostoianie vegetativnoi nervnoi sistemy u bol'nykh s rannei postinfarktnoi stenokardiei.

Ninety-three patients with acute myocardial infarction were examined. They were divided into 2 groups: 1) those with early postmyocardial infarction angina pectoris and 2) those without it. The autonomic nervous system was studied by exploring its segmental and suprasegmental regions. The autonomic tone was evaluated by variance intervalometry. The test of human lymphocytic rosette formation and bovine red blood cells sensitized with glutaric aldehyde and loaded epinephrine was applied to estimate the adrenoception. The sympathetic tone and tissue adrenoceptor density were found to be higher in patients with early postinfarction angina than in those without it. The finding may be useful in predicting early postinfarction angina in patients with acute myocardial infarction.