🚀 go-pugleaf

In article <1992Jul5.234607.21750@nas.nasa.gov> eugene@wilbur.nas.nasa.gov (Euge
ne N. Miya) writes:
>>>I've heard that if you eat a small bit of poison oak that you will
>>>become immune.  Needless to say, I've never tried this!

Immune isn't the right concept, though the immune system is involved in 
hyposensitization. 


>
>My my, this is what one gets when asking the net for medical advice.
>This is potentially lethal.
>I guess we did evolve this way.  Carry on.
>
>>Don't try this. An esophagus or trachea which is swollen shut can ruin
>>your whole day. In fact, it can kill you.
>
>Saner heads prevail.
>

As for choice of information sources, ENM could be right, but in this
instance, it's not the case that it will have these effects.

A couple of summers ago I looked this up on Medline and got an
abstract reporting no such ill effect but also no hyposensitization.
When this thread started I tried the same search but that ref wasn't
to be found.  I did, however, find this:

Search request: F KW URUSHIOL AND KW ORAL
Search result:  1 citation in the Medline database

1. Stampf JL; Castagnoli N; Epstein W; Baldwin RW; Byers V.
     Suppression of urushiol-induced delayed-type hypersensitivity responses in
   mice with serum IgG immunoglobulin from human hyposensitized donors.
     Journal of Investigative Dermatology, 1990 Sep, 95(3):363-5.
     Unique ID:  90347265.

Abstract: Serum IgG immunoglobulin fractions from human subjects hyposensitized
    to poison ivy/oak by oral administration of urushiol suppressed the
    induction of delayed-type hypersensitivity (DTH) responses in mice to this
    hapten. This suppressive activity was hapten specific because it did not
    modify DTH responses to dinitrofluorobenzene (DNFB). Absorption of human
    serum with lymph node cells from urushiolsensitized but not DNFB-sensitized
    mice removed the suppressive activity, suggesting that anti-idiotypic
    antibodies reacting with T-cell receptors are involved.

which suggests that humans can be hyposensitized by oral administration
of urushiol.  I haven't yet had the chance to find that reference
(I should next week) but I'd expect to find the previous reference
I mentioned cited, or at least something that would shed a little
more light on the matter at issue.

Other references I found indicate that transport of urushiol from
the skin surface into basal cell layers is active and mediated by
about 1% of a certain group of lymphocytes.  Which means that whatever
is done following exposure must be done FAST.  Organoclay, according
to the references available on-line, is the most effective PREVENTATIVE
application:

Search request: F KW ORGANOCLAY
Search result:  1 citation in the Medline database

1. Epstein WL.
     Topical prevention of poison ivy/oak dermatitis.
     Archives of Dermatology, 1989 Apr, 125(4):499-501.
     Unique ID:  89192429.

Abstract: An organoclay preparation was evaluated for topical protection
    against experimental poison ivy/oak in a rigorous double-blind study. By
    direct comparison with the same subject, it proved more effective than
    comparable preparations of bentonite, kaolin, or silicone in 16 of 17
    trials. When evaluated globally against control responses to urushiol the
    organoclay preparation gave 95.3% protection against topical urushiol
    applications, ranging from 4.75 to 0.0475 nmol. Bentonite, kaolin, and
    silicone gave 29.6%, 37.9%, and 32.9% protection, respectively, in the same
    system. We conclude that organoclay is an effective topical protectant
    against experimental poison ivy/oak dermatitis, and deserves further
    clinical evaluation.

---
More later.

Ely.