Radon activity concentration--a Euromet and BIPM supplementary comparison.

For the first time, a comparison of radon activity concentration in air has been performed within the scope of Euromet. In the project 657, 'Comparison of calibration facilities for the radon activity concentration,' 12 participants from 9 countries compared different radon reference atmospheres at 1, 3 and 10 k Bq m-3 via a transfer standard. The comparison was listed as BIPM supplementary comparison EUROMET.RI(II)-S1. The results of most participants are correlated due to common traceability to one single radon gas standard producer. This makes a careful correlation analysis necessary to achieve an appropriate comparison reference value. The results of the comparison as well as the complex analysis of the correlated set of data is presented and discussed.

Intercomparison exercise of the PTB, BfS, MPA and PSI calibration facilities for radon gas concentration.

The traceability chain of one national reference laboratory (PTB) and three accredited radon calibration laboratories (BfS MPA and PSI) to internationally acknowledged radon gas standards is specified. As an additional tool for quality assurance, interchange of an electronic radon measuring instrument was used as a means for a relative comparison of the radon gas reference atmospheres. The instrument was exposed to radon gas activity concentrations between 500 Bq.m(-3) and 15 kBq.m(-3). Measured sensitivities of the participants agree well inside the range of specified calibration uncertainties.

[The liver concentration of cephradin and cephacetril and their elimination in the bile]. / Die Lebergewebekonzentration von Cephradin und Cephacetril sowie deren Gallenausscheidung

Liver biopsies and serum samples were collected after intravenous application of 2 g cephradin (n = 13) or 2 g cephacetril (n = 11) during surgery. There was no difference in the serum levels of cephradin and cephacetril. 30 min. after i.v. application of cephradin the liver tissue concentration was 72.62 mcg/g. 30 min. after i.v. cephacetril the liver tissue concentration was 5.83 mcg/g. The quotient of liver tissue concentration to serum concentration for cephradin was between 0.36 and 0.83, and for cephacetril between 0.02 and 0.16. The excretion of cephradin and cephacetril in human bile was studied by collecting bile samples from the common bile duct via T-tube drainage (n = 17). Cholecystomized patients were given 2 g of antibiotics intravenously. Serum levels of cephradin were 263 mcg/ml 5 min after application, and 22 mcg/ml after 240 min. Serum levels of cephradin were 263 mcg/ml 5 min after application, and 22 mcg/ml after 240 min. Serum levels of cephacetril were 193 mcg/ml 5 min after application, and 27 mcg/ml after 240 min. The highest levels of cephradin in the bile were found 75 min after injection at a concentration of 86.4 mcg/ml; the highest level for cephacetril was 21.8 mcg/ml at 15 min. In patients with hyperbilirubinaemia cephradin reached a mean maximum concentration of 29.6 mcg/ml in bile samples, in comparison to 117.4 mcg/ml in normal patients, while no difference was seen with cephacetril. After intravenous administration of 2 g cephradin biliary concentration are achieved which may be sufficiently high to be effective not only against the very sensitive gram-positive organisms, but also against most strains of E. coli, Klebsiella and indol-negative Proteus. Cephradin is effective in the treatment of cholangitis and intrahepatic abscesses, as was observed in 18 patients. A free bile-flow is essential.