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Developing the powdered media industry


David Kritchevsky and the ball mill
Leonard Hayflick Scientist
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The problem that I had was discussed with David Kritchevsky, a colleague of mine who had a laboratory across the hall, and with whom I drove daily in his car, because our houses were fairly close together, and we often chatted about mutual problems, etc. David was a world-renowned lipid chemist, and after hearing my problem he... he suggested a possible resolution, which turned out to be correct, after some glitches that I'll explain in a moment.

David's work, which needs to be described in order to understand why he made the suggestion, involved the preparation of various pellets to feed rabbits that he used to study in his lipid chemistry experiments. He was connected well with a company that simply took David's written list of ingredients, that he buried, of course, in his experimental designs. Took those chemicals, and put them into what's called a 'ball mill', which is a long cylindrical piece of equipment made... usually made out of some heavy metal, into which one puts either stones or metal bearings or metal balls, and also the chemical mixture of interest. This long device is then rotated on rollers, and of course, the balls are bouncing around and breaking the powder down to an extraordinarily fine dust, and that allows for the dissolution of those chemicals much more easily than if they went in in larger particle sizes. David wasn't too concerned about that for his work. After the powders were removed from the ball mill, they were then turned into large pellets and fed to the rabbits.

So, David and I decided to take the chemicals that I was interested in, because I had told him earlier, or had asked him why I couldn't take all of these chemicals, and there were about 40 or 50, put them into a mortar and pestle, grind them up and then add water? And he laughed, and said that he... it was apparent to him that I had no knowledge, fundamental knowledge of physical chemistry. I had suggested that more or less as a joke, in order to draw him out, for a possible explanation.

Leonard Hayflick (b. 1928), the recipient of several research prizes and awards, including the 1991 Sandoz Prize for Gerontological Research, is known for his research in cell biology, virus vaccine development, and mycoplasmology. He also has studied the ageing process for more than thirty years. Hayflick is known for discovering that human cells divide for a limited number of times in vitro (refuting the contention by Alexis Carrel that normal body cells are immortal), which is known as the Hayflick limit, as well as developing the first normal human diploid cell strains for studies on human ageing and for research use throughout the world. He also made the first oral polio vaccine produced in a continuously propogated cell strain - work which contributed to significant virus vaccine development.

Listeners: Christopher Sykes

Christopher Sykes is a London-based television producer and director who has made a number of documentary films for BBC TV, Channel 4 and PBS.

Tags: David Kritchevsky

Duration: 2 minutes, 55 seconds

Date story recorded: July 2011

Date story went live: 08 August 2012