Bone water studied by differential centrifugation.

Abstract

The binding of water in bone was re-examined by differential centrifugation. Specimens of human trabecular were cleaned in a jet stream of water, degassed in water, and subjected to centrifugation fields, varying from 100 to 27.000 g's in sealed vials in a refrigerated centrifuge. Specimens were run in groups of six. The specimens were subjected to 4 centrifugation fields with rehydration and degassing between treatments. The specimens were dried and the residual water after each treatment was calculated. Specimens were centrifuged in a particular field until no further weight loss occurred with further centrifugations. There was a rapid exponential drop in water content as a function of centrifugation force between 120 and 1000 g's. The exponential nature of the loss and its sudden exhaustion suggest one discrete, extremely loosely bound compartment probably corresponding to the water on the outside surfaces of the specimens. Above 1000 g's there was no detectable decrease in water content to the maximal field of 27.000 g's. This would suggest that no interior water within the lacunae, canaliculi or interstitial space was removed by centrifugation fields below 27.000 g's. Calculations are presented which reval that centrifugation fields of about 800.000 g's would be required to even begin to remove the water from canaliculi. It is concluded that the interior bone water is held too tightly by capillary forces to be evaluated by centrifugation.