Marrow mass and distribution in murine skeletons cleaned by beetles as compared to cut up carcasses and a further simplification of the latter technique.

Distribution of 59Fe into various bone groups of the complete murine skeleton was studied using two methods of dividing up the bones: 1) our previously reported technique of simply cutting up a skinned, eviscerated carcass and 2) separating bones from skeletons cleaned of overlying tissue by beetles, Dermestes species. The total percentage of injected 59Fe recovered in the sum of all skeletal parts, the percentage of total skeletal 59Fe found in each bone group, and the overall accuracy of determining these values were quite similar for the two techniques. The only statistically significant difference shown was a modest decrease in the percentage of total skeletal iron found in ribs plus sternum plus cervical and thoracic spine in beetle-cleaned as compared to cut up groups and we would not consider this to be of biological significance. Cutting up carcasses is the simpler of the two techniques but there are circumstances in which beetle digestion would be advantageous. In addition, we collected data on the reproducibility and precision of determining the percentage of 59Fe injected which is found in a "pulled off" foreleg plus scapula and of the distribution of 59Fe within three cut up pieces from the leg and within the scapula. These data can be used as a measure of overall changes in marrow mass and/or distribution, or at least they can be used as a screening procedure to detect such. This simple procedure adds potentially useful values for fully interpreting hematopoietic changes in the mouse.