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Biomedical subjects

K Niemax

Publications and source records attributed to K Niemax.

4 recordsLinked to original sources
PubMed2001

Laser ablation--reflections on a very complex technique for solid sampling.

This paper is an attempt to point out the complex correlations between the experimental conditions in solid sampling by lasers. In particular, the influence of the laser properties, the surrounding gas, and the matrix on the analytical results of laser ablation techniques, such as laser induced breakdown spectrometry or laser ablation-ICP-MS, will be discussed.

Journal Article↗
PubMed2000

The effect of oxytocin, prostaglandin E2 and acetylsalicylic acid on flow distribution and on the transfer of alanine, glucose and water in isolated perfused guinea pig placentae.

The influence of oxytocin (OXY), sulproston (SUL) and acetylsalicylic acid (ASA) on L-alanine- (ALA), D-glucose- (GLU) or water- (H(2)O) uptake (maternal side) in the isolated perfused guinea pig placenta was investigated. Uptake was measured with a single injection, paired tracer dilution method. 'T50' values were derived from venous concentration curves (extracellular marker) as the distance (sec) between two concentration values at 50 per cent of peak concentration. T50 values were regarded to reflect the change of flow distribution on the maternal side. On average, there was a significant apparent inhibition of GLU uptake (by 27.2 per cent from control values) by OXY as well as of ALA uptake by OXY (26. 0 per cent), by ASA (56.6 per cent), and by SUL (56.7 per cent). The respective mean T50 values decreased significantly in the above groups by 15.9 per cent, 18.7 per cent (ns), 42.2 per cent and 56.7 per cent. However, it was not possible to generate dose-response curves whereas significant correlations of uptake values with T50 values were found. There was no dose-response relationship between T50 values and OXY or ASA concentrations but decreased mean T50 values were found. For SUL a weak correlation of T50 and SUL concentration was found. The r -value of GLU uptake and T50 was 0.57, for H(2)O uptake this value was 0.70, for ALA uptake the r -values were 0.51 (OXY), 0.35 (SUL) and 0.31 (ASA). Correlation of uptake and concentrations were not significant. We conclude that the 'inhibitory' effects of OXY, ASA and probably SUL on placental transfer are unspecific and the consequence of flow shifts from the placental exchange area to the uterine muscle.

Alanine↗