Date: Thu, 15 Aug 91 00:13:46 -0700
From: Lamont Granquist <[lamon t g] at [milton.u.washington.edu]>
To: [a--er--m] at [spot.Colorado.EDU]
Subject: Re: Question re. Heath Studies
Newsgroups: alt.psychoactives,alt.drugs

Okay, if you check out:  Benson, "Marijuana and Health", 1982 its a
study done by the Institute of Medicine which in Chapter 4 ("Effects of
Marijuana on the Brain") has some critiques of Heath's shit.  I've also
got Heath's studies sitting here in front of me, and I guess that qualifies
me as knowing what the fuck I'm talking about.  I've also hashed out Heath's
studies with an M.D. from Louisiana who called me up a few weeks ago.

from "MJ & Health":

Three post mortem studies on monkeys in the same laboratory have
reported changes in the microscopic morphology of the brain at the
ultrastructural level (Harper er al., 1977; Meyers and Heath, 1979;
Heath et al., 1980.) NO SIMILAR STUDIES ON HUMAN BEINGS HAVE BEEN 
REPORTED.  The monkeys received either chronic exposure to marijuana
smoke or chronic injections of delta-9-THC.  Changes reported to have
occured in the brains included alteration in synaptic cleft width,
increased density of synaptic cleft material, a decrease in volume of
rough endoplasmic reticulum, presence of clumping of synaptic vesicles
in axon terminals (where impulses travel away from the cell body),
and an increase in intranuclear inclusions.  These changes appear
dramatic, but they must be interpreted with caution.  The three
studies are based principally upon examination of TWO LIMITED BRAIN
AREAS ONLY IN THREE TREATED MONKEYS, two receiving marijuana smoke
and one intravenous delta-9-THC; a fourth treated animal was added to
the last study and more brain areas were analyzed in it (Heath et
al., 1980).  Further, although the material was evaluated
"doubleblind" after electron micrographs had been made, it would
appear that FIXATION, TISSUE PREPARATION, AND PHOTOGRAPHY WERE
CARRIED OUT BEFORE THESE SAFEGUARDS AGAINST BIAS WERE APPLIED.  It is
possible that unknown but systematic differences occured between
experimental (treated) and control animals in fixation and
preparation of tissue or in selection of samples for micrography.  In
addiction, it should be noted that AT LEAST ONE OF THE CHANGES NOTED,
CLUMPING OF THE SYNAPTIC VESICLES (Harper et al., 1977), IS A NORMAL
VARIANT IN THE SYNAPTIC MORPHOLOGY OF AXON TERMINALS IN MAMMALIAN
BRAIN (Sipe and Moore, 1977) and does not represent a pathological
change.  Also, these studies have not been replicated and, because
the basis for interpretation is such a limited sample, it is con-
cluded that no definitive interpretation can be made at this time.
However, the possibility that marijuana may produce chronic, ultra-
structural changes in brain has not been ruled out and should be
investigated.

All the caps lock shit was mine, obviously.  Now for an examination of
just exactly what they said here:

First, don't be put off by their conclusion that brain damage has not
been ruled out.  Two studies in 1977 in the Journal of the American 
Medical Association failed to find brain damage in marijuana users using
Computed Tomography (Co et al., pg 1229, Kuehnle et al., pg 1231).  One
of them used a group of heavy smokers (mean 9.0 joints/day) without any
controls over consumption, with measurements performed blind.  The other
used subjects in controlled environment with subjects smoking an average
of more than 5 joints/day for 21 days.  Both studies contradict the findings
of Campbell in 1971 who, using pneumoencephalographic methods, found brain
damage in Marijuana smokers.  "MJ & Health" gives a rational explanation for
this difference, in part because CT is superior to pneumoencephalography and
also because Campbell did not eliminate users of other drugs such as
Amphetamines (which is known to cause brain damage) from his study.  This
means that there is considerable evidence that marijuana does not cause
brain damage.  Unfortunately it does not completely eliminate Health's 
studies since Computed Tomography would not have found the brain damage
that Health claimed to have found, however Heath's studies aren't worth
the paper they were printed on (and I feel sorry for those damn monkeys).

Its really important to point out that all of the "Brain Damage" the Health
found under the microscope could have been fabricated.  As "MJ & Health"
said, fixation, tissue preparation and photography were carried out before
the samples were evaluated.  This means that Heath could have simply decided
to use samples which visually appeared to be "Damaged" but in actuality 
were areas of brain that were within normal limits.  Thus, he found
clumping of synaptic vesicles...

Also, its interesting that the monkeys that Health found brain damage
in were smoking the "equivalent to seven joints per day for man".  Its
interesting because he killed two of his monkeys in this group.  One at
5 1/2 months and another at 3 1/2 months.  They died of "respiratory
complications".  Since I've known several people who have smoked seven
joints per day for significantly longer than 6 months, I would suspect
Health of either outright lying or mistreating his monkeys.

Also, I believe that the areas that he found brain damage (the septal
region, hippocampus, and amygdala) do not correlate with the known activity
of marijuana in the brain.  I haven't been able to dig this up, however,
so DON'T QUOTE ME ON THIS ONE.  The rest I'm positive is accurate.

Have fun. =)

-- 
Lamont Granquist 
[lamon t g] at [u.washington.edu]