Pharmacy and Therapeutics - January 2008 - (Page 13) NEW DRUGS Can Stem Cells Reverse Sickle Cell Anemia? Scientists may have discovered a way to correct the mutation for sickle cell anemia in mice. They have succeeded in using cells almost identical to embryonic stem cells to correct the disorder. They were able to create induced pluripotent stem (iPS) cells from human skin cells. About 10% of people, mostly AfricanAmericans, carry the mutation for sickle cell anemia. In these patients, the red blood cells become sickle-shaped and cannot move easily through the blood vessels. The creation of iPS cells may obviate the need to use embryos. The scientists were using reprogrammed cells to make hematopoietic cells, which can produce different blood and immune cells, to treat the genetic defect in mice. Embryonic stem cells are pluripotent; that is, they can develop into virtually any cell type in the body. The hope is that such cells may yield treatments or cures for diabetes, liver failure, spinal injury, stroke, Alzheimer’s disease, and heart disease. However, harvesting embryonic stem cells involves destroying a viable embryo. In the U.S., embryonic stem cell research has been severely limited since August 2001. Since that time, researchers have tried to find other sources of viable stem cells, and iPS cells are one outcome of this effort. For this study, researchers took skin cells from the tails of mice with sickle cell anemia and used them to produce iPS cells. They then replaced the mutated gene with a healthy gene in the new cells. After the iPS cells had differentiated into hematopoietic stem cells, they were reintroduced into the mice, where they began to produce healthy blood cells. The procedure, however, has potential drawbacks: it can result in cancer (although none of the mice had evidence of tumors), and retroviruses were used to DRUG NEWS NEW MEDICAL DEVICES Marvin M. Goldenberg, PhD, RPh, MS Name: CustomVue Monovision LASIK Manufacturer: Advanced Medical Optics/Visx, Santa Clara, Calif. Approval Date: July 12, 2007 Use Classification: LASIK (laser in situ keratomileusis) is a surgical procedure in which one eye is corrected for far vision and the other eye is treated for near vision. Description: The surgeon cuts a flap in the outer layers of the cornea, removes a small amount of the tissue beneath it with the laser, and replaces the flap. The procedure enables monovision correction in nearsighted adults, with or without astigmatism, who are 40 years of age or older and have normal age-related loss of ability to focus on near objects. Purpose: The surgery is designed to correct all of the nearsightedness in the dominant eye and only part of the nearsightedness in the nondominant eye. As a result, patients can use the fully corrected eye for distance vision and the under corrected eye for near vision.The brain eventually adjusts to the difference in perception between the two eyes. Benefit: Because the operation is permanent, patients considering this procedure should first wear monovision contact lenses for at least one week to determine whether they can tolerate the undercorrection in one eye. Following monovision surger y, the two eyes might not always work together as well as they did before, especially in dim light or when patients are performing tasks requiring sharp vision or fine depth perception. Patients may need to wear glasses or contact lenses for night driving or reading small type. Side effects can include glare from bright lights, halos around lights, light sensitivity, glare during night driving, ghost images, double vision, and visual introduce healthy genes into the mice. (Sources: Science, December 6, 2007; www.sciencemag.org; Forbes.com; www. forbes.com.) Patients with Diabetes and Sickle Cell Trait Need Sound Hemoglobin Test The National Institutes of Health is highlighting the importance of using accurate methods of testing glycosylated hemoglobin (HbA1c) in diabetic patients with sickle cell trait or other inherited forms of variant hemoglobin. The specific needs for testing blood glucose control in these patients are explained in two booklets, Sickle Cell Trait and Other Hemoglobinopathies and Diabetes: Important Information for Physicians and For People of African, Mediterranean, or Southeast Asian Heritage: Important Information about Diabetes Blood Tests. The test, an essential tool in diabetes care, shows the average level of blood glucose control in the previous two to three months. Physicians base treatment decisions in large part on these results. Inaccurate readings, when they are falsely high or low, may lead to the overtreatment or undertreatment of diabetes. Intensive control of blood glucose, blood pressure, and cholesterol reduces heart disease and the other complications of diabetes. Having sickle cell trait or another hemoglobin variant does not increase a person’s risk for diabetes. The hemoglobin test is not used in diabetic patients with sickle cell anemia because of the shortened life span of red blood cells. Diabetes falls heavily on minorit y groups. About 13 percent of AfricanAmericans age 20 and older have diabetes, a rate that is nearly twice that of non-Hispanic Caucasians. (Source: NIH, November 28, 2007.) Vol. 33 No. 1 • January 2008 • P&T® 13 http://www.sciencemag.org http://Forbes.com http://forbes.com http://forbes.com
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