Wednesday, January 13, 2010

Mmm-mmm Cadmium, Part I

Via ProMED-mail: the Associated Press found cadmium in children's jewelry imported to the US from China. The LA Times reports:

For China's low-cost jewelry makers, it was an open trade secret: The metal cadmium is shiny, strong and malleable at low temperatures, regardless of its health hazards. And it's cheap.
Despite the risks, manufacturers in factories ringing this city on China's east coast say their top priority is profit. So offering cut-rate goods often means using lower quality materials, including cadmium, which is known to cause cancer.
"Business is business, and it's all up to our client," said He Huihua, manager of the Suiyuan Jewelry Shop at International Trade City in Yiwu[...]
Asked what he thought about the health risks associated with cadmium and other toxic metals, He said: "I can't be overly concerned about that."

PlagueBlog recommends a trade embargo.

Saturday, January 09, 2010

Mmm-mmm Melamine, Part M

Via ProMED-mail: another melamine scandal has broken in China, once again belatedly, and once again involving tainted milk. The Wall Street Journal reports that the two-month investigation of Shanghai Panda Dairy Company began almost a year ago.

Shanghai Panda, one of the nation's smaller dairies, was among 22 companies originally implicated in the 2008 scandal and was briefly shut by quality inspectors.
Now, among the allegations against the company are that instead of destroying its melamine-tainted product that had been recalled in 2008, Shanghai Panda reconstituted the milk into new products.


Sunday, January 03, 2010

Prion Evolution

Ed Yong discusses prion evolution in his blog at ScienceBlogs:

Jiali Li from the Scripps Institute in Florida has found that prions - the infectious proteins behind mad cow disease, CJD and kuru - are capable of Darwinian evolution, all without a single strand of DNA or its sister molecule RNA.
Prions are rogue version of a protein called PrP. Like all proteins, they are made up of chains of amino acids that fold into a complex three-dimensional structure. Prions are versions of PrP that have folded incorrectly and this misfolded form, called PrPSc, is social, evangelical and murderous. It converts normal prion proteins into a likeness of its abnormal self, and it rapidly gathers together in large clumps that damage and kill surrounding tissues.
Li has found that variation can creep into populations of initially identical prions. Their amino acid sequence stays the same but their already abnormal structures become increasingly twisted. These "mutant" forms have varying degrees of success in different environments. Some do well in brain tissue; others thrive in other types of cell. In each case, natural selection culls the least successful ones. The survivors pass on their structure to the "next generation", by altering the folds of normal prion proteins.