Task: Explanation
Input (English): Paragraph: Food and Drug Administration officials said they are trying  to determine whether the chemical — over-sulfated chondroitin  sulfate — was purposely or inadvertently added during  manufacturing in China. “We don’t know whether the contaminant was introduced  intentionally or by accident,” said Dr. Janet Woodcock,  director of the FDA’s Center for Drug Evaluation and Research. Chondroitin sulfate is widely sold as a dietary supplement  to treat joint pain. The over-sulfated version is not known to  occur naturally and therefore likely was chemically modified,  Woodcock told reporters on a conference call. It is still unclear whether the contaminant is the cause of  up to 19 deaths and hundreds of serious breathing problems and  other reactions reported to the FDA, she said. The substance mimics the blood-thinning actions of heparin  but is not FDA-approved for use in medicines, Woodcock said. In  some batches, the contaminant accounted for between 2 percent  and 50 percent of the samples, she said. FDA officials said chemically manipulating chondroitin  sulfate, which is widely available from animal sources, would  be cheaper than getting raw heparin from pig intestines. Last year, the FDA found pet food ingredients imported from  China were tainted, killing more than 200 cats and dogs and  causing widespread alarm. The Chinese maker involved was later  indicted in the United States for fraud over adding the  chemical melamine in an attempt to bolster the value of its  ingredient. The pet food case drew attention to China’s role in the  U.S. food and drug supply and ignited criticism over the FDA’s  lack of oversight — and little cooperation from its Chinese  counterparts. This time around, FDA officials said they are getting  needed help from China. “It’s quite a different scenario than we had a year ago,”  FDA’s Deputy Commissioner for International Affairs Murray  Lumpkin, told reporters on the phone, while speaking from  China. FDA’s Woodcock said it remains unclear whether the heparin  contamination was intentional. Many scientists are studying  over-sulfated chondroitin sulfate, which could have  accidentally made its way into heparin products, she said. The FDA announced on March 5 it had found a “heparin-like”  contaminant in some of the drug’s active ingredient supplied to  Baxter by a plant in Changzhou, China, owned by Wisconsin-based  Scientific Protein Laboratories. Investigators had been working  since then to determine its precise identity. In a statement, Scientific Protein Laboratories said a  consultant working for the Changzhou plant concluded the  contaminant is not linked to the plant’s production but likely  occurred earlier in the supply chain. Baxter, in a statement, agreed with the FDA’s finding of  over-sulfated chondroitin sulfate but also said the substance  contaminated the product before it reached SPL. FDA spokeswoman Siobhan DeLancey said the agency was still  investigating at what point the contamination occurred. Meanwhile, U.S. lawmakers tentatively scheduled hearings on  the issue for April 15 and April 22. “This latest development underscores our concerns that FDA  does not have a robust enough presence overseas in conducting  inspections,” House of Representatives Energy and Commerce  Committee Chairman John Dingell, a Michigan Democrat, said in a  statement. Last month, Baxter recalled most of its U.S. supplies of  heparin, used in kidney dialysis as well as heart and other  surgeries to prevent blood clots. The FDA has received more than 785 reports of heparin  reactions, including 19 deaths in patients treated with some  brand of heparin. Baxter has said only four fatalities might be  related to its heparin and there is not enough information to  say the drug was the cause. The agency has told border inspectors to stop all shipments  of imported heparin intended for the U.S. market so they can be  tested for the contaminant. Germany also has ordered a recall of heparin made by  Rotexmedica after reports of allergic reactions there. Claim: FDA pinpoints contaminant in Baxter's heparin.
Output (English): U.S. health regulators said on  Wednesday they have identified a contaminant found in batches  of Baxter International Inc’s blood-thinner heparin that were  linked to serious reactions and deaths.