Spectroscopy of element 115 decay chains

A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

[Serum level-adjusted dosage of once-daily aminoglycoside therapy in critical illness: results of a prospective study]

OBJECTIVE

In critically ill patients, the adjustment of target peak and trough levels of tobramycin was investigated because aminoglycoside pharmacokinetics can be changed by multiple influences. Sufficient but not too high peak serum concentrations and low trough levels, however, should be achieved to ensure a therapeutic effect and to minimize toxicity.

METHODS

70 critically ill patients of 51 +/- 18 years were monitored daily during their aminoglycoside treatment on the intensive care unit targeting a peak of about 12 micrograms/ml 30 minutes after infusion and a trough level below 1 to 2 micrograms/ml. Dose recommendations were given daily, taking into consideration serum levels, dose predictions (Bayesian method, ABBOTTBASE), creatinine clearance and clinical findings. Creatinine clearance was estimated according to the Cockcroft-Gault-formula as well as directly by the urine collection method.

RESULTS

The standardized initial dose of 400 mg tobramycin led to average peak serum levels of 14.2 +/- 3.9 micrograms/ml in the patients with an apparent distribution volume of 0.345 +/- 0.074 L/kg. In 95% of the patients, the initial peak was higher than 8.5 micrograms/ml; levels higher than 20 micrograms/ml were observed in 7%, extremely low concentrations (below 5 micrograms/ml) in 2%. With individually adjusted doses between 160 and 560 mg, a mean peak of 11.5 +/- 2.7 micrograms/ml was measured subsequently. The levels amounted to 96 +/- 23% of the predicted values, deviations greater than 50% occurred in 5%. The target trough level was achieved in 99%, in less than 3% the dosing interval was extended up to 72 hours. A tobramycin clearance below 80 ml/min/1.73 m2 was associated with average 80% and 33% higher creatinine clearance values according to the Cockcroft-method and the direct method, respectively.

CONCLUSION

Target peak and trough aminoglycoside levels are adjustable even in critically ill patients. Reduced tobramycin clearance can be associated with normal creatinine clearance. Assuming an exact methodology, a reduced "direct" creatinine clearance, however, indicates a reduced drug clearance.

Time-action profile of inhaled insulin

We compared the pharmacodynamics of insulin after inhalation of 99 U microcrystalline solid insulin and subcutaneous injection of 10 U regular insulin and intravenous injection of 5 U regular insulin. The time-action profiles of the three insulin administrations were studied in 11 healthy volunteers using the euglycaemic glucose clamp technique. The insulins were administered to each volunteer on three separate occasions in random order. Onset of action, assessed as glucose infusion rate, after insulin inhalation was substantially more rapid than after subcutaneous injection and half-maximal action was reached earlier (31 +/- 17 vs 54 +/- 12 min; p < 0.001). Maximal metabolic response was reached earlier after insulin inhalation in comparison to subcutaneous injection (108 +/- 49 vs 147 +/- 53 min; p < 0.001). The maximal glucose infusion rate after inhalation of insulin was lower than after subcutaneous insulin injection (6.2 +/2- 2.4 vs 9.1 +/- 2.5 mg kg-1 min-1; p < 0.001). The glucose infusion rates in the first 60 min after inhalation were significantly greater than after insulin injection (area under the glucose infusion rate curve: 0.23 +/- 0.12 vs 0.13 +/- 0.08 g kg-1 60 min-1; p < 0.001). However, the total metabolic effect after inhalation was significantly lower than after insulin injection (1.44 +/- 0.68 vs 1.90 +/- 0.47 g kg-1 360 min-1; p < 0.001). Relative effectiveness of inhaled insulin calculated with regard to the data from the intravenous insulin application was 9.5 +/- 4.1% and of the subcutaneous insulin application was 7.6 +/- 2.9%. With its rapid onset of action, inhaled insulin might have potential for clinical use.