Xref: utzoo sci.med:6384 sci.bio:1350 Path: utzoo!attcan!uunet!husc6!linus!philabs!aecom!werner From: werner@aecom.YU.EDU (Craig Werner) Newsgroups: sci.med,sci.bio Subject: Infinite dilutions revisited Keywords: Don't start cheering for Homeopathy. Message-ID: <1907@aecom.YU.EDU> Date: 22 Jul 88 01:05:19 GMT Distribution: na Organization: Albert Einstein Coll. of Med., NY Lines: 78 Recently, both in this newsgroup and in the general scientfic and popular press, there was a lot of discussion about a rather amazing experiment done in France by Jacques Benveniste of INSERM at the South Paris University that suggests that certain compounds can be diluted infinitely without necessarily losing biological activity. I will attempt to review the actual experiment, and explain why, opinions to the contrary, it really doesn't much further the cause of homeopathy all that much. The experiment: The experiment deals with the immunology of the allergic response, namely the IgE-allergen induced degranulation of Mast Cells, which causes the release of histamine and other allergic mediators. Normally, IgE is bound to the cell surface of mast cells via the FcEI (pronounced F c epilson One ) receptor. Allergen cross-links the IgE, and the "capping" of the IgE sets off allergic responses. As a universal allergen, one can use anti-IgE antibody, which cross-links all IgE regardless of which antigen the IgE naturally binds. If one does this, one finds that the results actually fall into two parts. The first is what you expect, an arbitrary 100% activity falls to a very low value with dilution, i.e., the active component gets diluted out. However, with further dilution, the activity INCREASED to an intermediate value, and then decreased, and increased again in a periodic fashion. This pattern continued to a dilution of 10^-120, well beyond the molecular limit where one would expect any molecules of the original mixture to be remaining. This periodic behavior was robust -- it replicated on different trials -- although the phase was not constant between trials (i.e., on one trial, peaks might be seen at dilutions 45 49 53 57 etc, while on a later trial, no activity would be seen on those dilutions, but would appear in dilutions 47 51 55 59 etc.) All the relevant controls seemed to behave as expected, the most telling being that when anti-IgG serum (which has no initial activity) was used instead of anti-IgE, the activity started at zero and stayed there. This implies that one must dilute active ingredient, even if it is to absurdly low concentrations. Another interesting phenomenon was that the handling of the compounds was important. If following dilution, only gentle mixing was applied, no activity wa recorded. Activity was only recorded if the tubes were subjected to 10 seconds of vigorous vortexing. An interesting and intriguing experiment all around. Now here's why it is not all that relevant to homeopathy: First of all, dilution didn't really increase activity beyond what chemical principles would suggest. The highest biological activity was noted at the lowest (Zero) dilution. What the experiment noted was a cyclical fluctuation between low and moderate activity. Secondly, homeopathy purports to treat "like with like", which is to say, that a little bit of a compound will prevent the symptoms that a lot of the compound would cause. In this experiment, all that "like" seemed to do was cause variable symptoms at the various low doses. Thirdly, the fact that the parallel experiments had differences phases means that predicting which dilution of a homeopathic preparation contains active compound is impossible without a bioassay. Since this is just the sort of the thing that homeopaths disdain, there is no way to predict the efficacy of a homeopathic preparation. Considering that the number of dilutions are standardized, then this experiment still shows that homeopathy is a hit or miss business (which is if you think about it, an upgrading of status from a miss or miss business). This is reinforced by the observation the the results of the experiment are dependent on sample preparation, which in the absence of a bioassay, means there is even less means of quality control. Fourth, homeopathy predicts that dilution will increase a substances potency, not that its potency will vary cyclically between 0 and 40% effectiveness. Thus the results of the experiment does not agree with either the dogmas of homeopathy or the dogmas of pharmacology. The best popular science summary appears in New Scientist 14 July 1988 (p. 39). The Newsweek and Science News articles are too superficial. The Nature article (333:816) is really thick reading, even by the standards of scientific writing. -- Craig Werner (future MD/PhD, 4 years down, 3 to go) werner@aecom.YU.EDU -- Albert Einstein College of Medicine (1935-14E Eastchester Rd., Bronx NY 10461, 212-931-2517) "Time flies when you're streaking out N. gonorrheae."