Re: Warning on cannabis use & impaired immune system

On 7 Aug, 09:18, "Harry McCulla" <harry.mccu...@xxxxxxxxxxxxxxxx>
wrote:
"Claude" <Cla...@xxxxxxx> wrote in message

news:memo.20070806182057.1392C@xxxxxxxxxxxxxxxxxx

http://www.sciencedaily.com/releases/2007/08/070801112156.htm

http://tinyurl.com/2evbdv

Cannabis could combat cancer
Last updated at 12:14pm on 15th September 2004
Cannabis could provide an unlikely new weapon in the fight against cancer,
new research suggests today.
Scientists have discovered that the active ingredient in cannabis combats
cancer-causing viruses.

Experiments show the active cannabis ingredient tetrahydrocannibol (THC) can
prevent the activation and replication of gamma herpes viruses.

Two of these viruses, Kaposis Sarcoma Associated Herpes Virus and
Epstein-Barr virus, predispose infected individuals to the cancers Kaposis
sarcoma, Burkitts lymphoma and Hodgkins disease.

Gamma herpes viruses are different from the herpes simplex viruses
responsible for cold sores and genital herpes.

Kaposis sarcoma is especially prevalent among Aids sufferers and is now the
most common form of cancer in Africa.

Once infected, it is almost impossible to get rid of the viruses as they lie
dormant for long periods within white blood cells.

The dormant viruses can reactivate, replicating themselves and bursting out
of the cells to spread between individuals and cause illness.

Scientists at the University of South Florida in the United States found
that reactivation was prevented if infected cells were grown in the presence
of THC.

Cells infected with a mouse gamma herpes virus normally died when the virus
reactivated. But they survived when cultured with the cannabinoid compound.

Writing in the on-line journal BMC Medicine, the scientists showed that THC
acted specifically on gamma herpes viruses. It was unable to prevent the
reactivation of the cold sore virus herpes simplex-1.

Team leader Dr Peter Medveczky and his fellow researchers wrote: "We believe
that studies on cannabinoids and herpes viruses are important to continue
because there are obvious benefits.

Better understanding may lead to the development of specific
non-psychoactive drugs that may inhibit reactivation of cancer-causing
herpes viruses."

Dr Medveczky pointed out that THC could also suppress the immune system -
and patients infected with these viruses often had weakened immune systems
already.

Whether or not the beneficial effects of THC outweighed this hazard was yet
to be tested in mice.

"We have not evaluated the effect of THC in an animal model yet," said Dr
Medveczky.

"Therefore, our findings do not recommend that people take pot to prevent or
treat cancers associated with gamma herpesviruses."

Dr Medveczky believes THC targets a viral gene shared by gamma herpes
viruses called ORF50. By preventing activation of this gene, the compound is
thought to block viral replication.

Marijuana Myths, Claim No. 5


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CLAIM #5:
MARIJUANA IMPAIRS IMMUNE SYSTEM FUNCTIONING

It has been widely claimed that marijuana substantially increases
users' risk of contracting various infectious diseases. First emerging
in the 1970s, this claim took on new significance in the 1980s,
following reports of marijuana use by people suffering from AIDS.

THE FACTS

The principal study fueling the original claim of immune impairment
involved preparations created with white blood cells that had been
removed from marijuana smokers and controls. After exposing the cells
to known immune activators, researchers reported a lower rate of
"transformation" in those taken from marijuana smokers. 26

However, numerous groups of scientists, using similar techniques, have
failed to confirm this original study. 27
In fact, a 1988 study demonstrated an increase in responsiveness when
white blood cells from marijuana smokers were exposed to immunological
activators. 28

Studies involving laboratory animals have shown immune impairment
following administration of THC, but only with the use of extremely
high doses. For example, one study demonstrated an increase in herpes
infection in rodents given doses of 100 mg/kg/day - a dose
approximately 1000 times the dose necessary to produce a psychoactive
effect in humans. 29
There have been no clinical or epidemiological studies showing an
increase in bacterial, viral, or parasitic infection among human
marijuana users. In three large field studies conducted in the 1970s,
in Jamaica, Costa Rica and Greece, researchers found no differences in
disease susceptibility between marijuana users and matched controls.
30

Marijuana use does not increase the risk of HIV infection; nor does it
increase the onset or intensity of symptoms among AIDS patients. 31 In
fact, the FDA decision to approve the use of Marinol (synthetic THC)
for use in HIV-wasting syndrome relied upon the absence of any
immunopathology due to THC. 32

Today, thousands of people with AIDS are smoking marijuana daily to
combat nausea and increase appetite. There is no scientific basis for
claims that this practice compromises their immune responses. Indeed,
the recent discovery of a peripheral cannabinoid receptor associated
with lymphatic tissue should encourage aggressive exploration of THC's
potential

.

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