Month: August 2010

Why do some people have a high tolerance for pain, while others experience the slightest touch as painful? Why do some injured soldiers perform heroic feats and claim that they felt no pain at the time?

Nobody quite knows, but new findings by Meinhart Zenk and Toni Kutchan at the Donald Danforth Plant Science Center offer some tantalizing possibilities.

Humans and other mammals excrete morphine in their urine. That has been known for a long time. The levels of morphine are also known to vary widely. The source of the morphine has been the unanswered question until now.

Zenk and colleagues in Germany showed in a recent article that mice, and presumably all mammals, have the metabolic equipment to manufacture morphine from the amino acid tyrosine, found in all proteins. Furthermore, the way morphine is produced by mammals mimics the same chemical steps as the pathway that the opium poppy uses.

 

Read the entire article (100KB PDF).
This article was originally published in the St. Louis Beacon.

Women who are diagnosed with breast cancer may soon be helped by a discovery made in 1880 by Alexander Graham Bell.

Currently, the removal of the lymph nodes draining the breast is a routine diagnostic procedure to see whether the cancer has spread. The surgery is invasive and often has significant side effects, including fluid retention, swelling and limited range of motion. In most cases — 80 percent — the test shows that the cancer hasn’t spread. That is a relief to the patient. But both doctors and patients have long hoped for a way to learn these results without surgery.

Now Washington University professors are developing techniques using Bell’s photoacoustic effect. The new imaging technology being developed by Lihong Wang and his colleagues will identify the sentinel lymph node (the first one to drain the breast) and guide the doctor in taking a needle biopsy. For most patients, that biopsy will reveal that the cancer has not spread and those underarm nodes can remain in place and keep working to drain the area.

What is the photoacoustic effect, and how does it translate to medical imaging?

 

Read the entire article (750KB PDF).
This article was originally published in the St. Louis Beacon.