Baldness and Other Medical News

Wednesday, January 26, 2011 // Uncategorized

Getting Closer to the Root of What Causes Baldness


[resreport1] Getty ImagesA decline in a special type of stem cell found in hair follicles may be responsible for pattern baldness.

Male pattern baldness: A decline in activity by a special type of stem cell, known as a progenitor cell, found in human hair follicles appears to be responsible for male pattern baldness, according to a study in the Journal of Clinical Investigation. Male pattern baldness, or androgenetic alopecia (AGA), which affects as many as two-thirds of U.S. men by the age of 50, has previously been linked to testosterone and other factors. Researchers analyzed skin cells from bald and nonbald scalp tissue taken from 54 U.S. men who were undergoing hair transplants. They found both samples had the same number of stem cells but bald scalps had 10 times fewer progenitor cells. Stem cells in hair follicles normally transform into progenitor cells, which in turn produce normal hair strands, the researchers said. But in men with AGA this process is blocked and no hair is produced or is “miniaturized.” In a related experiment, the researchers injected a type of cell similar to a human progenitor cell into mice and were able to create new hair follicles and hair growth. Understanding the signals that turn stem cells into progenitor cells is the next step toward developing new treatments, researchers said.

Caveat: The study was small and included only white men.

Title: Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells

Ectopic pregnancy: Doctors may be able to diagnose a tubal ectopic pregnancy before it becomes a medical emergency by testing cells from the placenta for the presence of a growth factor, according to a study in the Journal of Clinical Endocrinology and Metabolism. Ectopic pregnancy, the leading cause of U.S. maternal death in the first trimester, happens when a fertilized egg implants itself outside the uterus, most often in the fallopian tube, where it can rupture. There is currently no test for tubal pregnancy. Researchers analyzed trophoblast cells from the placenta from 40 pregnant women about to undergo surgery for ectopic pregnancy, miscarriage or abortion. In women with tubal pregnancies, levels of placental growth factor (PIGF), a protein that promotes the formation of new blood vessels, were almost undetectable compared with levels in other patients. Researchers said the differential secretion of PIGF could be an important diagnostic biomarker for the condition and recommended large-scale studies.

Caveat: Technical difficulties plus contamination of some uterine samples prevented collection of trophoblast cells from every patient. The study sample was small.

Title: Placental Growth Factor: A Promising Diagnostic Biomarker for Tubal Ectopic Pregnancy

Shingles: A relatively new vaccine for shingles that isn’t yet widely distributed significantly reduced the risk of the viral disease in older adults, including the more serious form of shingles that attacks the eye, according to a study in the Journal of the American Medical Association. Shingles, or herpes zoster, is caused by the reactivation of the chicken pox virus and characterized by a painful blistery rash that erupts along the nerves. Of the estimated one million cases of shingles in the U.S. every year, about 25% are the ophthalmic form. An analysis of data from a Southern California health system found the risk of shingles was reduced by 55% in 75,761 members age 60 and older who received the vaccine when compared with 227,283 unvaccinated members. The risk of ophthalmic shingles was reduced by 63%. The study, which was carried out by the health system without external funding, confirms the findings of an earlier study led by the Department of Veterans Affairs in collaboration with the National Institute of Allergy and Infectious Diseases and Merck & Co., which was licensed in 2006 to produce the vaccine.

Caveat: The study involved residents of one region of the country so the results may not apply to the general population. The follow-up period was short and not designed to record a decline in the vaccine’s protection.

Title: Herpes Zoster Vaccine in Older Adults and the Risk of Subsequent Herpes Zoster Disease

HDL efflux: The capacity of HDL, or “good cholesterol,” to remove cholesterol from human cells is a better predictor of cardiovascular risk than a static numerical measurement of HDL, according to a study in the New England Journal of Medicine. Studies have consistently shown that a high HDL reading is associated with a reduced risk of coronary artery disease but certain drugs that elevate HDL have raised questions about those findings. Researchers used a special incubator to measure both the quantity and quality of HDL, called efflux capacity, in 442 people with confirmed atherosclerosis and 351 healthy controls. After adjusting for age, sex, smoking status, diabetes and HDL levels, the study found patients with the highest efflux capacity had a 52% reduced risk of coronary disease compared to those with the lowest. In a separate group of 203 participants, efflux capacity had a significant inverse relationship with carotid-artery thickness, a known risk factor for coronary-artery disease. By contrast, carotid-artery thickness had no association with a numerical measurement of HDL. The researchers said the findings could be important in the assessment of new therapies targeting HDL metabolism.

Caveat: Efflux capacity is only one measurement of the complex cellular processes involved in the transport and disposal of cholesterol.

Title: Cholesterol Efflux Capacity, High-Density Lipoprotein Function, and Atherosclerosis

Blood thinners: Use of the widely prescribed anticoagulant warfarin doubles a patient’s risk of dying or suffering complications following an injury, according to a study in Archives of Surgery. Warfarin is a blood thinner commonly used to prevent heart attacks, stroke and blood clots. Its chief side effect is a heightened risk for hemorrhage. A study of 1,230,422 patients admitted to hospitals in the U.S. and Puerto Rico from 2002 to 2006 found that 36,270 were taking warfarin. The rate of death among warfarin users was 9.3% compared with 4.8% for non-warfarin users. Of warfarin users under 65 admitted with severe head injury, 51% died while only 37% of non-warfarin users died. Researchers said the exact role of warfarin in adverse outcomes is not known but its use is a significant independent risk factor for death from injury, especially in younger patients. They recommend trauma centers take an accurate history of warfarin use and develop protocols for reversing warfarin following an injury.

Caveat: Researchers were unable to identify patients admitted to hospital who were previous users of warfarin or to track compliance with outpatient use of the drug.

Title: Prevalence and Implications of Preinjury Warfarin Use

Second-hand smoke: Passive exposure to second-hand smoke caused more than 600,000 premature deaths world-wide, or about 1% of all deaths, in 2004, according to a study in the Lancet. Researchers estimated deaths and disease caused by second-hand smoke in 192 countries using national and international surveys, including a global youth tobacco survey, and comparing risk factors for different diseases with the proportion of a population exposed to second-hand smoke. Modeling was used to assess exposure in countries without survey data. About 40% of children, 33% of male nonsmokers and 35% of female nonsmokers were exposed to second-hand smoke in 2004. More than half the deaths were from heart disease, followed by lower-respiratory infections, asthma and lung cancer. Nearly half the deaths and disease attributed to second-hand smoke occurred in Southeast Asia and the western Pacific. The study notes that 93% of the world’s population lives in countries not covered by smoke-free laws that would rapidly reduce deaths from tobacco.

Caveat: Estimates of exposure to second-hand smoke may be flawed because of gaps in data for specific regions and variations in the definition of exposure in studies used by the researchers.

Title: Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries.


Getty ImagesA study suggests sedentary time should be seen as a health risk.



Sedentary time: Taking short breaks from sitting of even a minute or two throughout the day helps trim waistlines and reduce levels of C-reactive protein, an important inflammatory marker for heart disease, according to a study in the European Heart Journal that examined the health effects of prolonged sitting in sedentary and active people. Smaller studies that used self-reported information have identified sedentary behavior as a unique risk factor for cardiovascular disease and premature death. This study, aiming for a more objective picture, outfitted 4,757 Americans (average age of 46.5 years) with accelerometers, lightweight instruments worn on the hip that measure movement in activity counts. Accelerometers were worn an average 14.5 hours a day for seven days between 2003 and 2006. On average, participants took 15.6 breaks a day, of about four minutes each, and were sedentary about 8.5 hours a day. The least amount of sedentary time was 1.8 hours a day and the most was 21.2 hours a day. People who took the most breaks had a 4.1-centimeter smaller waist circumference and significantly lower C-reactive protein levels than the most sedentary participants. The findings suggest that public-health guidelines identify sedentary time as a health-risk behavior, the researchers said.

Caveat: Accelerometers don’t distinguish between different postures or variations in walking conditions so some standing-still time may be included as sedentary time. Time spent wearing the instrument was estimated rather than measured directly.

Title: Sedentary time and cardio-metabolic biomarkers in US adults: NHANES 2003-06


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