Modification and testing of the Sandia Laboratories Livermore tritium decontamination systems

Sandia Laboratories, Livermore, has put into operation a new facility, the Tritium Research Laboratory. The laboratory incorporates containment and cleanup facilities such that any tritium accidentally released is captured rather than vented to the atmosphere. This containment is achieved with hermetically sealed glove boxes that are connected on demand by manifolds to two central decontamination systems called the Gas Purification System (GPS) and the Vacuum Effluent Recovery System (VERS). The primary function of the GPS is to remove tritium and tritiated water vapor from the glove box atmosphere. The primary function of the VERS is to decontaminate the gas exhausted from the glove box pressure control systems and vacuum pumps in the building before venting the gas to the stack. Both of these systems are designed to remove tritium to the few parts per billion range. Acceptance tests at the manufacturer's plant and preoperational testing at Livermore demonstrated that the systems met their design specifications. After preoperational testing the Gas Purification System was modified to enhance the safety of maintanance operations. Both the Gas Purification System and the Vacuum Effluent Recovery System were performance tested with tritium. Results show that concentraion reduction factors (ratio of inlet to exhaust concentrations) much in excess of 1000 per pass have been achieved for both systems at inlet concentrations of 1 ppM or less

Disposition of total and unbound prednisolone in renal transplant patients receiving anticonvulsants

AbstractDisposition of total and unbound prednisolone in renal transplant patients receiving anticonvulsants. Kidney transplant patients receiving phenytoin or phenobarbital may have decreased graft survival. These drugs have been shown to enhance the metabolism of glucocorticoids. We determined the disposition of total and unbound prednisolone in six stable kidney transplant patients receiving prednisone for immunosuppression and phenytoin or phenobarbital for a seizure disorder. Six similar patients not on anticonvulsants served as controls. A single intravenous dose of prednisolone was administered, and plasma samples were analyzed for prednisolone using a high-performance liquid chromatographic assay. Equilibrium dialysis was used to determine unbound prednisolone concentrations. Pharmacokinetic analysis showed that the half-life of prednisolone was shorter in the anticonvulsant group compared to the controls, based on both total (2.3 ± 0.4 vs. 3.4 ± 0.2hr (SD), P < 0.01) and unbound (1.7 ± 0.3 vs. 2.4 ± 0.2 hr, P < 0.01) concentrations. Total drug clearance was 10.4 ± 2.8 liters/hr (0.171 ± 0.087 liters/hr · kg) in the anticonvulsant group versus 7.2 ± 1.2 liters/hr (0.100 ± 0.014 liters/hr · kg) in the controls (P < 0.05). Unbound prednisolone clearance was 57.2 ± 12.1 versus 46.4 ± 8.7 liters/hr (P > 0.05) and for weight-corrected estimates 0.886 ± 0.224 liters/hr · kg versus 0.644 ± 0.115 liters/hr · kg (P < 0.05) in the two groups, respectively. Thus, the disposition of prednisolone is altered by anticonvulsants in kidney transplant patients and may require dose alteration.Disparition de la prednisolone totale et libre chez des transplantés rénaux recevant des anticonvulsivants. Les transplantés rénaux recevant de la phénytoïne ou du phénobarbital pourraient avoir une survie du greffon diminuée. Ces médicaments se sont avérés capables de stimuler le métabolisme des glucocorticoïdes. Nous avons déterminé l'élimination de la prednisolone totale et libre chez six transplantés rénaux stables recevant de la prédnisone pour leur immunosuppression et de la phénytoïne ou du phénobarbital pour une épilepsie. Six malades identiques sans anticonvulsivants ont servi de contrôle. Une dose unique intraveineuse de prednisolone a été administrée, et des échantillons plasmatiques ont été analysés pour la prednisolone en utilisant un dosage par chromatographie liquide à haute pression. Une dialyse à l'équilibre a été utilisée pour déterminer les concentrations de prednisolone non liée. L'analyse pharmacocinétique a montré que la demi-vie de la prednisolone était plus courte dans le groupe aux anticonvulsivants par rapport aux contrôles, qu'il s'agisse des concentrations totales (2,3 ± 0,4 contre 3,4 ± 0,2hr (SD), P < 0,01) ou libres (1,7 ± 0,3 contre 2,4 ± 0,2 hr, P < 0,01). La clearance totale du médicament était de 10,4 ± 2,8 litres/hr (0,171 ± 0,087 litres/hr · kg) dans le groupe anticonvulsivant contre 7,2 ± 1,2 litres/hr (0,100 ± 0,014 litres/hr· kg) chez les contrôles (P < 0,05). La clearance de la prednisolone non liée était de 57,2 ±12,1 contre 46,4 ± 8,7 litres/hr (P > 0,05), et après correction pour le poids de 0,886 ± 0,224 litres/hr · kg contre 0,644 ± 0,115 litres/hr · kg (P < 0,05) dans les deux groupes, respectivement. Ainsi, l'élimination de la prednisolone est altérée par les anticonvulsivants chez les transplantés rénaux et peut imposer des modifications de la dose