In vitro degradation of atracurium.
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Atracurium↗
Biomedical subjects
R Stiller
Publications and source records attributed to R Stiller.
Oral pemoline kinetics in hyperactive children.
The time course of pemoline in plasma was investigated in seven prepubescent boys with attention-deficit disorders who were hyperactive. Maximum plasma concentrations of 4.3 +/- 1.0 mg/L were reached 2.8 +/- 1.8 hours after a single, 2 mg/kg oral dose of pemoline, followed by a monoexponential decline in plasma concentration over time. Mean t1/2 and total body clearance of pemoline were 8.6 hours and 0.65 ml/min/kg. The 600% interindividual variation in elimination t1/2 and the 300% variation in total body clearance of pemoline may explain the unpredictable nature of its dynamics and associated neurotoxicity in some cases.
Absorption↗
Does switching to low tar/nicotine/carbon monoxide-yield cigarettes decrease alveolar carbon monoxide measures? A randomized controlled trial.
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Adult↗
Relationships among measures of smoking topography.
Interrelationships between puffing, puff duration, puff volume, and heart rate change were assessed in a sample of 63 chronic, high rate smokers. Results showed puff duration and volume were related for males and females, and that heart rate change was related to volume in males and puff duration in females. Puffs were not related to either volume or heart rate change in males or females. These results call into question research on smoking behavior which does not measure volume, and shows that components of puffing may not be used interchangeably, and that neither puffs nor puff duration are accurate predictors of volume of intake.
Adult↗
Calibration of a reflectance pulse oximeter in fetal lambs for arterial oxygen saturations below 70%.
OBJECTIVE: To calibrate a reflectance pulse oximeter developed at the Division of Perinatal Physiology, University Hospital of Zurich, for monitoring of oxygen saturations below 70%. METHODS: Oxygen saturation measured noninvasively with the reflectance pulse oximeter in fetal sheep was compared with oxygen saturation of arterial blood samples measured by a conventional two-wavelength oximeter. Oxygen saturation was varied by stepwise reduction of the inspired oxygen concentration of the ewe. RESULTS: A total of 58 data pairs was obtained from five fetuses, with a range of 10.9-73.5% for the reference method and 6.8-69.2% for the pulse oximetry oxygen saturation values. There was good correlation between the results obtained by the two methods (r2 = .89, P < .0001), with a 95% confidence interval of +/- 12.5%. The pulse oximeter showed a precision of 6.2% oxygen saturation. CONCLUSION: The Zurich reflectance pulse oximeter offers valid measurements of oxygen saturation levels down to 10% oxygen saturation, and is therefore suitable for monitoring the fetus during delivery.
Animals↗
Amniotic fluid polarization of fluorescence and lecithin/sphingomyelin ratio decision criteria assessed.
A negative finding of amniotic fluid (AF) phosphatidyl glycerol (PG) does not eliminate the need for determining the lecithin/sphingomyelin ratio (LSR). We use a novel approach to classify fetal lung maturity (FLM) data, and to validate the fluorescence polarization (FP) surfactant assay (Abbott), which replaces the PG assay and reduces the frequency of repeat LSR. This method finds the values (decision points) of these tests that allow for classifying the data with least errors. These tests best identify the risk of respiratory distress syndrome (RDS) from fetal lung immaturity. We find the decision values for tests by exploring the data for information content and optimize their selection using group-based reference. We previously defined normal reference as the maximum entropy set with no information. The uncertainty resolved by information provided in the data allows formation of syndromic classes. This is greatest at the values for the variables (decision-points) associated with the greatest decrease in entropy. Decision-values found for PF, EGA, PG, LSR that classify amniotic fluids into the mature and not-mature classes are in agreement with the results of ROC analysis. We validate the replacement of PG by the PF method. We also find a level of FP below which LSR might be required to resolve uncertainty and above which the FP indicates maturity. We confirm the ability to evaluate fetal maturity methods using information analysis.
Amniotic Fluid↗