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K Kramer

Publications and source records attributed to K Kramer.

158 records · Page 9Linked to original sources
PubMedDate not supplied

Studies on histaminergic compounds, Part VII. Histamine H2-binding on guinea-pig cerebral cortex compared to histamine (ant)agonism.

The pKD values of series of H2-active compounds, obtained from displacement curves of 3H-tiotidine from a guinea-pig cerebral cortex homogenate were compared with the pA2/pD2 values of these compounds on the right atrium of the same animal species. A good correlation was found between the cortex pKD value and the pharmacological activity on the right atrium, especially with the antagonists, the partial agonists and the agonistic impromidine analogues (guanidines). The poor correlation between cortex pKD and atrium pD2 of some other agonists (the amines) might be explained by the presence of spare receptors for these compounds. The different number of spare receptors for the guanidines and the amines might be explained by the differences in base strength of these compounds.

Animals↗
PubMedDate not supplied

Long-term monitoring of atrazine contamination in soil by ELISA.

An enzyme-linked immunoassay (ELISA) was used for screening atrazine residues in soil. Samples were annually collected in Southern Germany between 1993 and 1998. An average of 419.5 samples was analyzed per year amounting to 2517 samples. The fraction of positive samples defined by atrazine concentrations >100 microg/kg soil decreased successively from 8% (corresponding to 33 samples) in 1993 to 0.6% (corresponding to 2 samples) in 1998. All positive samples and a selection of negative samples were subsequently validated by HPLC. Comparison of ELISA and HPLC data yielded correlation coefficient values of r = 0.958-0.981 (n = 18-47), except for 1995 when only a correlation of r = 0.864 (n = 18) was obtained. Four samples were overestimated and another 4 were underestimated with respect to the atrazine threshold value of 100 microg/kg soil as revealed by HPLC validation. Thus, 99.68% of 2,517 analyzed samples were correctly evaluated. The precision and reproducibility of the ELISA were adequate for a prescreening tool. The low cost per sample and the high sample throughput are not yet achievable by conventional analytical methods. The described combination of ELISA and HPLC has the potential to take advantage of both methods and to restrict determination errors to a minimum.

Atrazine↗