豌豆爸爸 发表了文章 • 2 个评论 • 557 次浏览 • 2018-05-15 12:52
豌豆爸爸 发表了文章 • 0 个评论 • 570 次浏览 • 2018-02-09 14:44
Many kids (and parents) who have seen Luke Skywalker battle Darth Vader with a light saber think lasers are cool.
What they may not know is this: When operated unsafely, or without certain controls, the highly-concentrated light from lasers—even those in toys—can be dangerous, causing serious eye injuries and even blindness. And not just to the person using a laser, but to anyone within range of the laser beam.
The U.S. Food and Drug Administration is concerned about this potential danger to children and those around them and in 2014 issued a guidance document (PDF 60K) on the safety of children’s toy laser products.
“A beam shone directly into a person’s eye can injure it in an instant, especially if the laser is a powerful one,” explains Dan Hewett, health promotion officer at the FDA’s Center for Devices and Radiological Health.
Moreover, eye injuries caused by laser light usually don't hurt. Vision can deteriorate slowly and, therefore, may go unnoticed, for days and even weeks. Ultimately, the damage could be permanent, Hewett says.
Some examples of laser toys are:
- lasers mounted on toy guns that can be used for “aiming”;
- spinning tops that project laser beams while they spin;
- hand-held lasers used during play as “light sabers”; and
- lasers intended for entertainment that create optical effects in an open room.
The FDA Regulates Lasers
A laser creates a powerful, targeted beam of electromagnetic radiation that is used in many products, from music players and printers to eye-surgery tools. The FDA regulates radiation-emitting electronic products, such as lasers (including children’s toy laser products), and sets radiation-safety standards that manufacturers must meet.
Toys with lasers are of particular interest to the FDA because children can be injured by these products. Because they are marketed as toys, parents and kids alike may believe they’re safe to use.
For toys to be considered minimal risk, the FDA recommends that the levels of radiation and light not exceed the limits for Class 1, the lowest level in regulated products as defined by the International Electrotechnical Commission (IEC).
Lasers used for industrial and other purposes often need higher radiation levels for their intended functions. But these higher levels are not needed for children’s toys—and if they are present, they can be dangerous.
Hand-held laser pointers—often used in business and higher education to help illustrate presentations—have increased in power 10-fold or more over the last decade. And while adults may buy a laser pointer for use in work, kids often play with them for amusement.
The fact that lasers can be dangerous may not be evident, particularly to the children who inappropriately use them as toys, or to the adults who supervise them.
Laser Safety: Tips to Keep in Mind
Remember that laser products are generally safe when they follow the legal limits and are used as directed. But lasers can cause harm if not used properly. The FDA recommends the following general safety tips for consumers.
Never aim or shine a laser directly at anyone, including animals. The light energy from a laser aimed into the eye can be hazardous, perhaps even more than staring directly into the sun.
Do not aim a laser at any vehicle, aircraft, or shiny surface. Remember that the startling effect of a bright beam of light can cause serious accidents when aimed at a driver in a car, for instance, or otherwise negatively affect someone doing another activity (such as playing sports).
Look for an FDA-recommended IEC Class I label on children’s toy lasers. The label says “Class 1 Laser Product,” which would clearly communicate that the product is of low risk and not in a higher emission level laser class.
Do not buy laser pointers for children, or allow children to use them. These products are not toys.
Do not buy or use any laser that emits more than 5mW power, or that does not have the power printed on the labeling.
Immediately consult a health care professional if you or a child suspects or experiences any eye injury.
You can watch the FDA’s video on laser pointer safety [disclaimer icon] for more information.
Updated: November 24, 2017
豌豆爸爸 发表了文章 • 0 个评论 • 1159 次浏览 • 2018-02-09 14:32
Most people have had an X-ray taken at some time during their lives — perhaps checking for a possible broken bone or during a visit to the dentist. X-ray exams provide important information to physicians about how to treat their patients. However, X-rays use ionizing radiation, and these imaging exams must be carefully and judiciously used on pediatric patients.
While the level of risk from the radiation associated with X-rays is small, especially when compared with the benefits of an accurate diagnosis, health care professionals must be especially sensitive to their appropriate use in children. Pediatric patients generally require less radiation than adults to obtain a quality image from an X-ray exam, so doctors must take extra care to “child size” the radiation dose.
The FDA's Center for Devices and Radiological Health (CDRH) regulates medical imaging devices. Among its responsibilities is keeping consumers and health care professionals informed about the importance of minimizing unnecessary radiation exposure during medical procedures.
The level of ionizing radiation from X-ray imaging is generally very low, but can contribute to an increased risk of cancer. Because children have longer expected lifetimes ahead of them for potential effects to appear and the risk for cancer is not fully understood, it’s important to use the lowest radiation dose necessary to provide a diagnostic exam.
The FDA is committed to protecting the health of children by providing guidance to manufacturers and users of imaging devices to help lower the exposure to radiation from X-ray exams. The FDA has regulatory oversight of X-ray imaging devices and the companies that make them. To better address radiation safety concerns, the FDA has been encouraging both equipment improvements and better user information.
The FDA also promotes the adoption of improved radiation safety guidelines by professional organizations for both facilities and personnel.
In a new guidance FDA recommends that medical X-ray imaging exams be optimized to use the lowest radiation dose needed. These exams, which include computed tomography (CT), fluoroscopy, dental, and conventional X-rays, should be performed on children and younger patients only when the health care provider believes they are necessary to answer a clinical question or to guide treatment.
The FDA defines the pediatric population as birth through 21 years old. However, the optimization of image quality and radiation dose in X-ray imaging depends more on a patient’s size than their age. Smaller patients require less radiation to obtain a medically useful image. Technically, the patient’s body thickness (the distance an X-ray travels through the body to create the image) is the most important consideration when “child-sizing” an image protocol.
Unnecessary radiation exposure during medical procedures should be avoided. However, X-rays and CT scans should never be withheld from a child or adult who has a medical condition where the exam could provide important health care information that may aid in the diagnosis or treatment of a serious or even life-threatening illness.
What Parents Can Do
The FDA encourages parents and caregivers to talk to their child’s health care provider about X-rays and suggests:
- Keeping track of their child's medical-imaging histories
- Asking the referring physician about the benefits and risks of imaging procedures, such as: How will the exam improve my child's health care? Are there alternative exams to X-rays that are equally useful?
- Asking the imaging facility: How does the facility use reduced radiation techniques for children? Is there any advanced preparation necessary? Report any adverse events to the FDA.
The Role of Health Care Professionals
Health care professionals are responsible for ensuring there is justification for all X-ray imaging exams performed on pediatric patients. They should also consider whether another type of imaging exam that does not expose the patient to ionizing radiation, such as ultrasound or magnetic resonance imaging, could be used to obtain the same result.
The FDA encourages health care professionals and hospital administrators to refer to guidelines and instructions provided at the agency’s Pediatric X-ray Imaging web portal.
For more information visit the FDA’s Pediatric X-ray Imaging website.
January 9, 2018
豌豆爸爸 发表了文章 • 4 个评论 • 679 次浏览 • 2018-02-06 11:30
Dietary supplementation is approximately a $30 billion industry in the United States, with more than 90 000 products on the market. In recent national surveys, 52% of US adults reported use of at least 1 supplement product, and 10% reported use of at least 4 such products.1 Vitamins and minerals are among the most popular supplements and are taken by 48% and 39% of adults, respectively, typically to maintain health and prevent disease.
Despite this enthusiasm, most randomized clinical trials of vitamin and mineral supplements have not demonstrated clear benefits for primary or secondary prevention of chronic diseases not related to nutritional deficiency. Indeed, some trials suggest that micronutrient supplementation in amounts that exceed the recommended dietary allowance (RDA)—eg, high doses of beta carotene, folic acid, vitamin E, or selenium—may have harmful effects, including increased mortality, cancer, and hemorrhagic stroke.
In this Viewpoint, we provide information to help clinicians address frequently asked questions about micronutrient supplements from patients, as well as promote appropriate use and curb inappropriate use of such supplements among generally healthy individuals. Importantly, clinicians should counsel their patients that such supplementation is not a substitute for a healthful and balanced diet and, in most cases, provides little if any benefit beyond that conferred by such a diet.
Clinicians should also highlight the many advantages of obtaining vitamins and minerals from food instead of from supplements. Micronutrients in food are typically better absorbed by the body and are associated with fewer potential adverse effects. A healthful diet provides an array of nutritionally important substances in biologically optimal ratios as opposed to isolated compounds in highly concentrated form. Indeed, research shows that positive health outcomes are more strongly related to dietary patterns and specific food types than to individual micronutrient or nutrient intakes.
Although routine micronutrient supplementation is not recommended for the general population, targeted supplementation may be warranted in high-risk groups for whom nutritional requirements may not be met through diet alone, including people at certain life stages and those with specific risk factors (discussed in the next 3 sections and in the Box).
Box.Key Points on Vitamin and Mineral Supplements
General Guidance for Supplementation in a Healthy Population by Life Stage
Pregnancy: folic acid, prenatal vitamins
Infants and children: for breastfed infants, vitamin D until weaning and iron from age 4-6 mo
Midlife and older adults: some may benefit from supplemental vitamin B12, vitamin D, and/or calcium
Guidance for Supplementation in High-Risk Subgroups
Medical conditions that interfere with nutrient absorption or metabolism:
Bariatric surgery: fat-soluble vitamins, B vitamins, iron, calcium, zinc, copper, multivitamins/multiminerals
Pernicious anemia: vitamin B12 (1-2 mg/d orally or 0.1-1 mg/mo intramuscularly)
Crohn disease, other inflammatory bowel disease, celiac disease: iron, B vitamins, vitamin D, zinc, magnesium
Osteoporosis or other bone health issues: vitamin D, calcium, magnesiuma
Age-related macular degeneration: specific formulation of antioxidant vitamins, zinc, copper
Medications (long-term use):
Proton pump inhibitorsa: vitamin B12, calcium, magnesium
Metformin: vitamin B12 ( Inconsistent evidence.)
Restricted or suboptimal eating patterns: multivitamins/multiminerals, vitamin B12, calcium, vitamin D, magnesium
The evidence is clear that women who may become pregnant or who are in the first trimester of pregnancy should be advised to consume adequate folic acid (0.4-0.8 mg/d) to prevent neural tube defects. Folic acid is one of the few micronutrients more bioavailable in synthetic form from supplements or fortified foods than in the naturally occurring dietary form (folate). Prenatal multivitamin/multimineral supplements will provide folic acid as well as vitamin D and many other essential micronutrients during pregnancy. Pregnant women should also be advised to eat an iron-rich diet. Although it may also be prudent to prescribe supplemental iron for pregnant women with low levels of hemoglobin or ferritin to prevent and treat iron-deficiency anemia, the benefit-risk balance of screening for anemia and routine iron supplementation during pregnancy is not well characterized.
Supplemental calcium may reduce the risk of gestational hypertension and preeclampsia, but confirmatory large trials are needed.2 Use of high-dose vitamin D supplements during pregnancy also warrants further study.2 The American College of Obstetricians and Gynecologists has developed a useful patient handout on micronutrient nutrition during pregnancy.
Infants and Children
The American Academy of Pediatrics recommends that exclusively or partially breastfed infants receive (1) supplemental vitamin D (400 IU/d) starting soon after birth and continuing until weaning to vitamin D–fortified whole milk (≥1 L/d) and (2) supplemental iron (1 mg/kg/d) from 4 months until the introduction of iron-containing foods, usually at 6 months.5 Infants who receive formula, which is fortified with vitamin D and (often) iron, do not typically require additional supplementation. All children should be screened at 1 year for iron deficiency and iron-deficiency anemia.
Healthy children consuming a well-balanced diet do not need multivitamin/multimineral supplements, and they should avoid those containing micronutrient doses that exceed the RDA. In recent years, ω-3 fatty acid supplementation has been viewed as a potential strategy for reducing the risk of autism spectrum disorder or attention-deficit/hyperactivity disorder in children, but evidence from large randomized trials is lacking.
Midlife and Older Adults
With respect to vitamin B12, adults aged 50 years and older may not adequately absorb the naturally occurring, protein-bound form of this nutrient and thus should be advised to meet the RDA (2.4 μg/d) with synthetic B12 found in fortified foods or supplements.6 Patients with pernicious anemia will require higher doses (Box).
Regarding vitamin D, currently recommended intakes (from food or supplements) to maintain bone health are 600 IU/d for adults up to age 70 years and 800 IU/d for those aged older than 70 years. Some professional organizations recommend 1000 to 2000 IU/d, but it has been widely debated whether doses above the RDA offer additional benefits. Ongoing large-scale randomized trials (NCT01169259 and ACTRN12613000743763) should help to resolve continuing uncertainties soon.
With respect to calcium, current RDAs are 1000 mg/d for men aged 51 to 70 years and 1200 mg/d for women aged 51 to 70 years and for all adults aged older than 70 years. Given recent concerns that calcium supplements may increase the risk for kidney stones and possibly cardiovascular disease, patients should aim to meet this recommendation primarily by eating a calcium-rich diet and take calcium supplements only if needed to reach the RDA goal (often only about 500 mg/d in supplements is required).2 A recent meta-analysis suggested that supplementation with moderate-dose calcium (<1000 mg/d) plus vitamin D (≥800 IU/d) might reduce the risk of fractures and loss of bone mass density among postmenopausal women and men aged 65 years and older.
Multivitamin/multimineral supplementation is not recommended for generally healthy adults.8 One large trial in US men found a modest lowering of cancer risk,9 but the results require replication in large trials that include women and allow for analysis by baseline nutrient status, a potentially important modifier of the treatment effect. An ongoing large-scale 4-year trial (NCT02422745) is expected to clarify the benefit-risk balance of multivitamin/multimineral supplements taken for primary prevention of cancer and cardiovascular disease.
Other Key Points
When reviewing medications with patients, clinicians should ask about use of micronutrient (and botanical or other dietary) supplements in counseling about potential interactions. For example, supplemental vitamin K can decrease the effectiveness of warfarin, and biotin (vitamin B7) can interfere with the accuracy of cardiac troponin and other laboratory tests. Patient-friendly interaction checkers are available free of charge online (search for interaction checkers on drugs.com, WebMD, or pharmacy websites).
Clinicians and patients should also be aware that the US Food and Drug Administration is not authorized to review dietary supplements for safety and efficacy prior to marketing. Although supplement makers are required to adhere to the agency’s Good Manufacturing Practice regulations, compliance monitoring is less than optimal. Thus, clinicians may wish to favor prescription products, when available, or advise patients to consider selecting a supplement that has been certified by independent testers (ConsumerLab.com, US Pharmacopeia, NSF International, or UL) to contain the labeled dose(s) of the active ingredient(s) and not to contain microbes, heavy metals, or other toxins. Clinicians (or patients) should report suspected supplement-related adverse effects to the Food and Drug Administration via MedWatch, the online safety reporting portal. An excellent source of information on micronutrient and other dietary supplements for both clinicians and patients is the website of the Office of Dietary Supplements of the National Institutes of Health.
Clinicians have an opportunity to promote appropriate use and to curb inappropriate use of micronutrient supplements, and these efforts are likely to improve public health.
豌豆爸爸 发表了文章 • 0 个评论 • 600 次浏览 • 2017-12-25 10:03
The genes in your body’s cells play an important role in your health — indeed, a defective gene or genes can make you sick.
Recognizing this, scientists have been working for decades on ways to modify genes or replace faulty genes with healthy ones to treat, cure or prevent a disease or medical condition.
Now this research on gene therapy is finally paying off. Since August 2017, the U.S. Food and Drug Administration has approved three gene therapy products, the first of their kind.
Two of them reprogram a patient’s own cells to attack a deadly cancer, and the most recent approved product targets a disease caused by mutations in a specific gene.
What Are Cells and Genes? How Do They Interact?
What is the relationship between cells and genes?
Cells are the basic building blocks of all living things; the human body is composed of trillions of them. Within our cells there are thousands of genes that provide the information for the production of specific proteins and enzymes that make muscles, bones, and blood, which in turn support most of our body’s functions, such as digestion, making energy, and growing.
How Gene Therapy Works
Sometimes the whole or part of a gene is defective or missing from birth, or a gene can change or mutate during adult life. Any of these variations can disrupt how proteins are made, which can contribute to health problems or diseases.
In gene therapy, scientists can do one of several things depending on the problem that is present. They can replace a gene that causes a medical problem with one that doesn’t, add genes to help the body to fight or treat disease, or turn off genes that are causing problems.In order to insert new genes directly into cells, scientists use a vehicle called a “vector” which is genetically engineered to deliver the gene.
Viruses, for example, have a natural ability to deliver genetic material into cells, and therefore, can be used as vectors. Before a virus can be used to carry therapeutic genes into human cells, however, it is modified to remove its ability to cause an infectious disease.
Gene therapy can be used to modify cells inside or outside the body. When it’s done inside the body, a doctor will inject the vector carrying the gene directly into the part of the body that has defective cells.
In gene therapy that is used to modify cells outside of the body, blood, bone marrow, or another tissue can be taken from a patient, and specific types of cells can be separated out in the lab. The vector containing the desired gene is introduced into these cells. The cells are left, to multiply in the laboratory, and are then injected back into the patient, where they continue to multiply and eventually produce the desired effect.
Before a Gene Therapy Can Go On the Market …
Before a company can market a gene therapy product for use in humans, the gene therapy product has to be tested for safety and effectiveness so that FDA scientists can consider whether the risks of the therapy are acceptable in light of the benefits.
Gene therapy holds the promise to transform medicine and create options for patients who are living with difficult, and even incurable, diseases. As scientists continue to make great strides in this therapy, FDA is committed to helping speed up development by prompt review of groundbreaking treatments that have the potential to save lives.
December 19, 2017
豌豆爸爸 发表了文章 • 0 个评论 • 964 次浏览 • 2017-10-23 11:18
Whether you’re a ghost or zombie, vampire or witch, poor costume choices—including decorative (colored) contact lenses and flammable costumes—and face paint allergies can cause injuries that haunt you long after Halloween.
Enjoy a safe and happy Halloween by following these guidelines from FDA, the Consumer Product Safety Commission, and the Centers for Disease Control and Prevention:
- Wear costumes that say “flame resistant” on the label. If you make your costume, use flame-resistant fabrics such as polyester or nylon.
- Wear bright, reflective costumes or add strips of reflective tape so you’ll be more visible; make sure the costumes aren’t so long that you’re in danger of tripping.
- Wear makeup and hats rather than masks that can obscure your vision.
- Test the makeup you plan to use in advance. Put a small amount on the arm of the person who will be wearing it. If a rash, redness, swelling, or other signs of irritation develop where the makeup was applied, that's a sign of a possible allergy.
- Vibrantly colored makeup is popular at Halloween. Check FDA’s list of color additives to see if the colors are FDA approved. If they aren’t approved for their intended use, don’t use them. This is especially important for colored makeup around the eyes.
- Don’t wear decorative (colored) contact lenses unless you have seen an eye care professional for a proper fitting and been given instructions for how to use the lenses.
Eating sweet treats is also a big part of Halloween fun.
Before you or your children go trick-or-treating, remember these tips:
•Don’t eat candy until it has been inspected at home.
•Eat a snack before heading out to avoid the temptation of nibbling on a treat before it has been inspected.
•In case of a food allergy, check the label to ensure the allergen isn’t present. Tell children not to accept—or eat—anything that isn’t commercially wrapped.
•Parents of very young children should remove any choking hazards such as gum, peanuts, hard candies, or small toys from the Halloween bags.
•Inspect commercially wrapped treats for signs of tampering, such as an unusual appearance or discoloration, tiny pinholes, or tears in wrappers. Throw away anything that looks suspicious.
For partygoers and party throwers, FDA recommends the following tips for two seasonal favorites:
•Unpasteurized juices and juices that have not been further processed are at higher risk of food- borne illness. Look for the warning label to identify juice that hasn’t been pasteurized or otherwise processed, especially packaged juice products made on site. If unsure, always ask if juice has been pasteurized or not. Normally, juice in boxes, bottles or cans from your grocer’s frozen food case, refrigerated section, or shelf has been pasteurized.
•Before bobbing for apples—a favorite Halloween game—reduce the risk of bacteria by thoroughly rinsing the apples under cool running water. As an added precaution, use a produce brush to remove surface dirt.
FDA joins eye care professionals—including the American Academy of Ophthalmology, the American Association for Pediatric Ophthalmology and Strabismus, the Contact Lens Association of Ophthalmologists and the American Optometric Association—in discouraging consumers from using illegal decorative (colored) contact lenses. These are contact lenses that have not been approved by FDA for safety and effectiveness. Consumers should only use brand name contact lenses from well-known contact lens companies.
If you have never worn contact lenses before, Halloween should not be the first time you wear them. Experts warn that buying any kind of contact lenses—which are medical devices and regulated as such—without an examination and a prescription from an eye care professional can cause serious eye disorders and infections, which may lead to permanent vision loss. Despite the fact that it’s illegal to sell decorative contact lenses without a valid prescription, FDA says the lenses are sold on the Internet and in retail shops and salons—particularly around Halloween.
The decorative lenses make the wearer’s eyes appear to glow in the dark, create the illusion of vertical “cat eyes,” or change the wearer’s eye color.
Although unauthorized use of decorative contact lenses is a concern year-round, Halloween is the time when people may be inclined to use them, perhaps as costume accessories. When they are bought and used without a valid prescription, without the involvement of a qualified eye care professional, or without appropriate follow-up care, it can lead to significant risks of eye injuries, including blindness.
更新日期: October 20, 2017
发布日期: October 26, 2010