Single-dose relative biological effectiveness and toxicity studies under conditions of hypothermia and hyperbaric oxygen

An approach to using hyperbaric oxygen with radiation in a clinical situation has been described in the preceding paper in this issue. To ascertain whether there might be a change in the relative biological effectiveness of radiation on normal mammalian tissue treated under conditions of hypothermia and hyperbaric oxygen, the acute reaction to radiation of pig skin was studied. A single dose enhancement ratio at the erythema reaction level of 1.4 +/- 0.08 was obtained when compared with irradiation at normal body temperature in air. We studied also a series of antioxidant enzymes in rat liver and lung after exposure to hypothermia and hyperbaric oxygen. Enzyme changes were such as to combat oxygen toxicity which might develop as a result of the pre-treatment.

Prostacyclin administration during cardiopulmonary bypass in man

In a double-blind trial prostacyclin was given to 12 of 23 patients undergoing coronary vein grafting. The treatment group showed a preservation of platelet number and function, with a halving of blood loss in the first 18 h postoperatively. The heparin sparing effect of prostacyclin was confirmed, as were the vasodilator effects which were not troublesome.

An interlaboratory survey of hydrogen ion and blood gas determinations

A survey of [H+], Pco2, and Po2 analyses in 360 laboratories was conducted using three commercial control materials: two aqueous gas-equilibrated buffer solutions (General Diagnostics and IL) and one whole blood material (DADE). There was little difference in precision or accuracy between instruments, classified according to manufacturer into four groups, and materials for [H+] and Pco2, or in precision for Po2. There were, however, differences in accuracy between instrument groups for Po2 analysis on the aqueous materials, and in some cases the mean values lay outside the range assigned by the material manufacturers. The 35 instruments outside clinical chemistry departments yielded results similar to those of all participants. The relation between inter- and intra-laboratory precision was similar to that for many analytes, suggesting that neither these materials nor the state of these analyses is unsatisfactory. Aqueous materials should, however, be used with caution as accuracy controls for Po2.

A comparative survey of the results of analyses of blood serum in clinical chemistry laboratories in the United Kingdom

Since July 1969, portions of the same blood serum have been dispatched to clinical chemistry laboratories in the United Kingdom at 14-day intervals. The results of each serum survey were reported to each of the 390 participants within 11 days of their originally receiving the specimen. During the first 18 months of the survey no overall improvement in the results was seen. Therefore a summary of each laboratory's ability consistently to produce results close to the mean of the method used was calculated and reported as a single figure, the variance index, and sent to all participants at regular intervals together with a histogram distribution of the variance indices of other participants. The subsequent improvement in the overall results is described.