PubMed · 14328054
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V TEICHMANN, J VANCURA. 1965-06-18. [CATHETERIZATION METHOD IN SPINAL PHLEBOGRAPHY].. https://pubmed.ncbi.nlm.nih.gov/14328054/
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Screening and diagnostic tests are important in disease prevention or control. The predictive values of positive and negative (PPV and NPV) test results are two of four operational characteristics of a screening test. We review an existing method based on the generalized estimating equation (GEE) methodology for comparing predictive values from the same sample of subjects and propose two Wald test statistics derived from the weighted least squares (WLS) method for the analysis of categorical data. Using these results, we propose sample size calculation formulae for this problem. Simulation studies are conducted to compare the performances of the two Wald test statistics (one based on the difference of two PPVs or NPVs, another based on the logarithm of the ratio of two PPVs or NPVs) and the score/Wald test statistic derived from GEE. We recommend using the difference-based WLS approach.
The general design of catheters is bound by many needs. Angiographic catheters must be rigid enough to be torquable and to maintain lumen structural integrity, but also flexible enough to bend with the curves of a blood vessel. They should cause minimal tissue damage; avoid biocompatibility-related complications, and be reliable over time. This study proposes a new testing approach to clearly identify the flexural rigidity of catheters by using a buckling test to evaluate the peak compressive load. This study also tests several angiographic catheters for axial and torsional rigidity. Seven different catheters used for short-term procedures, with and without reinforcement and of various sizes, were evaluated as a preliminary evaluation of test methods for future in vitro testing of catheters; it was found that the buckling test works very well and provides repeatable results.
PURPOSE: Isolated pelvic perfusion (IPP) therapy exposes target tissues to high doses of anticancer drugs with low systemic concentrations, but the major drawback is drug leakage into the systemic circulation, which often thwarts the increased drug concentration. In this study, the efficacy of altering the in-out flow rate during IPP in order to decrease the leakage was assessed in adult pigs. METHODS: The abdominal aorta and the infrarenal vena cava were occluded with two balloon catheters, blood in the extracorporeal circuit was circulated with twin rotary pumps, and the IPP was performed with platinum. Three sets of in-out flow rates were used, and the degree of drug leakage into the systemic circulation was evaluated. The volume of blood withdrawn was equal to the volume returned (300 ml/min; group A), 5% higher (group B), or 10% higher (group C). The platinum concentrations in the pelvic circulation, systemic circulation, and urine were measured and compared. RESULTS: The average and maximum plasma platinum concentrations in the pelvic circulation did not significantly differ among the three groups. The plasma platinum concentrations in the systemic venous circulation of the three groups significantly (P<0.01) decreased as the volume withdrawn during IPP increased. The percentage of platinum eliminated in the urine during IPP was significantly (P<0.01) lower in group B and C than in group A. CONCLUSIONS: Setting the volume withdrawn higher than the volume returned decreased leakage into the systemic circulation under isolated pelvic perfusion.