Sunday, March 06, 2016

Dr Thomas Rea, thalidomide, and Armadillos

Doctor Thomas Rea, a dermatologist who ran a clinic for Hansen's disease (leprosy) in California has died.

LATIMES: Dr. Thomas Rea, a dermatologist whose discoveries led to treatments that allowed patients with Hansen's disease - leprosy - to live without stigma, has died. He was 86. (Richard Dominguez)

 he worked to investigate the connection between the immune system and this disease.

One of the ways he did this was promoting the use of thalidomide to treat the painful and deforming aspects disease.

Some of us are old enough to remember the epidemic of malformed babies (lacking arms and legs) in Europe because docs used this medicine for the nausea of morning sickness.

Thanks to one stubborn lady doctor, Dr Frances Kelsey, working for the FDA,  it was never approved in the USA, but this epidemic was one of the reasons touted for the need to change the abortion laws back then.

Yet the medicine has limited uses because of it's use in treating painful Leprosy nodules, and also some cancers.

why does it work? From Everyday Health Site

Thalidomide is a type of drug called an immunomodulator. This means it works by altering the immune system or the body's ability to fight disease.
How it works in myeloma treatment is still being studied.
This is what the studies have shown so far:

Thalidomide blocks the flow of blood to tumor cells.
Thalidomide interferes with the growth of tumor cells in the bone marrow.
Thalidomide stimulates the immune system to attack tumor cells.
that part about blocking the growth of new blood vessels is why it helps those painful nodules and neurological problems in Leprosy, but it also is the reason that we see the limb defects in babies: it blocked new blood vessels needed in early pregnancy to supply blood to the limb buds.

I had a patient on it for his multiple myeloma, and he and his wife were required to sign lots of papers saying she would not get pregnant and that they would keep the medicine locked up.

this WAPO article is about it's use in cancer, and other diseases such as "graft vs host" problems after transplants.

Alas, in third world countries, regulation is not quite so good, so there are still a few babies born of moms taking the medicine every year.

related article: Leprosy in Medieval Europe

for medical historians, the interesting thing was that Leprosy was common in medieval Europe, but then disappeared (some think the Black Death plague killed most people due to their weakened immune system)...but one side effect was that most Europeans have inborn immunity to the disease.

and one factoid about the disease: the germ is impossible to grown in ordinary lab animals, except the foodpad of some mice--- and in the lowly armadillo, which are now used for lab experiments in the disease.

which leads us to this NYTimes article, that informs you that one third of all cases of leprosy in the US caught it from armadillos, and vice versa:

Some studies have shown that as many as 20 percent of armadillos in some areas are infected with leprosy.
WTF: armadillo?

Armadillos are often used in the study of leprosy, since they, along with mangabey monkeys, rabbits and mice (on their footpads), are among the few known species that can contract the disease systemically. They are particularly susceptible due to their unusually low body temperature, which is hospitable to the leprosy bacterium,Mycobacterium leprae. (The leprosy bacterium is difficult to culture and armadillos have a body temperature of 34 °C (93 °F), similar to human skin.) Humans can acquire a leprosy infection from armadillos by handling them or consuming armadillo meat.[14] Armadillos are a presumedvector and natural reservoir for the disease in Texas and Louisiana.
In Texas and the Southern USA, the most common place to see armadillos is dead in the middle of the road, leading to this variation of the common joke::

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