Letters

Earthquake rumblings
I reviewed this very interesting story (“Seismologists in a rumble over quake clusters,” SN: 5/7/11, p. 5) this morning, and it occurred to me that the connection between all of these very severe earthquakes might possibly be the change in weight distribution throughout the planet, resulting from temperature increases due to climate change with the melting of the glaciers: decreased weight where the glaciers were and increased weight of water on the ocean floors. Also, it seems as though the majority of them are clearly distributed around the rim of the Pacific Ocean (the “Ring of Fire”).
James R. Stewart Jr., Londonderry, N.H.

Researchers have linked melting glaciers and ice sheets to increased earthquake activity in places such as Greenland, Alaska and the Canadian Arctic. Removing overlying ice generally speeds up
the slip rate along geological faults.

However, there’s little evidence to suggest this is a significant factor at middle and low latitudes, including most of the locations that have seen large quakes in the last few years. — Alexandra Witze

The Parkinson’s bug
The story on a possible link between Helicobacter pylori and Parkinson’s disease (“Ulcer bug may trigger Parkinson’s, SN: 6/18/11, p. 18) was intriguing. Unfortunately, it was all mouse research. Are scientists going after human data, such as looking at the rate of Parkinson’s disease in persons who have had their Helicobacter eradicated as an ulcer preventive?
William Check, Evanston, Ill.

The article speculates that one way H. pylori might cause Parkinson’s is by modifying cholesterol into a toxic form. In August 2007, Science News reported that a drug, simvastatin, may reduce rates of Parkinson’s as well as dementias by roughly 50 percent. Might the drug produce its protective effect by either counteracting the action of H. pylori on cholesterol or by reducing the amount of cholesterol available to the bacteria?
Nancy Sutter Axford, Sacramento, Calif.

Some studies in people suggest H. pylori may play a role in Parkinson’s. Scientists in England found that Parkinson’s symptoms were lessened in people with the disease who had been successfully treated with antibiotics. But in patients who weren’t able to kick the bacteria, symptoms worsened. Traci Testerman, one of the researchers who led the new study in mice, thinks that antibiotics may have stressed the H. pylori bacteria, causing them to release even more of the modified cholesterol. — Tina Hesman Saey