GB toxicity reassessed using newer techniques for estimation of human toxicity from animal inhalation toxicity data: new method for estimating acute human toxicity (GB).

Estimated human inhalation toxicity values for Sarin (GB) were calculated using a new two independent (concentration, exposure time), one dependent (toxic response), non-linear dose response (toxicity) model combined with re-evaluated allometric equations relating to animal and human respiration. Historical animal studies of GB toxicity containing both exposure and fractional animal response data were used to test the new process. The final data set contained 6621 animals, 762 groups, 37 studies and 7 species. The toxicity of GB for each species was empirically related to exposure concentration (C; mg m(-3)) and exposure time (T; min) through the surface function Y = b0 + b1 Log10C + b2 Log10T or Y = b0 + b2 Log10C(n)T where Y is the Normit, b0, b1 and b2 are constants and n is the 'toxic load exponent' (Normit is PROBIT - 5). Between exposure times of 0.17 and 30 min, the average value for n in seven species was 1.35 +/- 0.15. The near parallel toxic load equations for each species and the linear relationship between minute volume/body weight ratio and the inhalation toxicity (LCt50) for GB were used to create a pseudo-human data set and then an exposure time/toxicity surface for the human. The calculated n for the human was 1.40. The pseudo-human data had much more variability at low exposure times. Raising the lower exposure limit to 1 min, did not change the LCt50 but did result in lower variability. Raising the lower value to 2 min was counterproductive. Based on the toxic load model for 1-30 min exposures, the human GB toxicities (LCt01, LCt05, LCt50 and LCt95) for 70 kg humans breathing 15 l min(-1) were estimated to be 11, 16, 36 and 83; 18, 25, 57 and 132 and 24, 34, 79 and 182 mg x min m(-3) for 2, 10 and 30 min exposures, respectively. These values are recommended for general use for the total human population. The empirical relationships employed in the calculations may not be valid for exposure times >30 min.

Education issues in disaster medicine: summary and action plan.

INTRODUCTION: Change must begin with education. Theme 8 explored issues that need attention in Disaster Medicine education. METHODS: Details of the methods used are provided in the introductory paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. The chairs then presided over a workshop that resulted in the generation of a set of action plans that then were reported to the collective group of all delegates. RESULTS: Main points developed during the presentations and discussion included: (1) formal education, (2) standardized definitions, (3) integration, (4) evaluation of programs and interventions, (5) international cooperation, (6) identifying the psychosocial consequences of disaster, (7) meaningful research, and (8) hazard, impact, risk and vulnerability analysis. DISCUSSION: Three main components of the action plans were identified as evaluation, research, and education. The action plans recommended that: (1) education on disasters should be formalized, (2) evaluation of education and interventions must be improved, and (3) meaningful research should be promulgated and published for use at multiple levels and that applied research techniques be the subject of future conferences. CONCLUSIONS: The one unanimous conclusion was that we need more and better education on the disaster phenomenon, both in its impacts and in our response to them. Such education must be increasingly evidence-based.

Allometric respiration/body mass data for animals to be used for estimates of inhalation toxicity to young adult humans.

The relationship between body weight (BW) and respiratory minute volume (V(m)) was reviewed by collecting a database from the literature. The data were separated into anaesthetized and non-anaesthetized groups. Only young adult terrestrial mammals were included in the final data set. This database is the largest to be reported to date, is the first to separate the anaesthetized and non-anaesthetized groups and is matched to the target population of young, fit adult humans. The data set of non-anaesthetized animals contained 142 studies representing 2616 animals and 18 species from mice at 12 g body weight to horses and a giraffe at ca. 500 kg body weight. Analysis of the data indicated a power law (allometric) relationship between the minute volume and body weight. The resulting allometric equations for the empirical relationship between minute volume and body weight are: log(10)V()(m)= -0.302 + 0.809 log(10)BW and V(m) = 0.499 BW(0.809)where V(m) is the minute volume (l min(-1)) and BW is the body weight (kg). From these equations, a minute volume of 15.5 lmin(-1)was obtained for a 70 kg human in the same physiological and/or emotional state as the animals. The results of the analyses were compared to other empirical studies in the literature, the more recent of which also indicated a scaling factor of 0.8. The relationship between minute volume and body weight is recommended for use in estimating the inhalation toxicity to young adult humans (military personnel), because this is the first study to use a large database focused exclusively upon non-anaesthetized young adult terrestrial mammals.