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Irritable bowel syndrome (IBS) is a disorder that interferes with the normal functions of the large intestine (colon). It is characterized by a group of symptoms--crampy abdominal pain, bloating, constipation, and diarrhea.
One in five Americans has IBS, making it one of the most common disorders diagnosed by doctors. It occurs more often in women than in men, and it usually begins around age 20.
IBS causes a great deal of discomfort and distress, but it does not permanently harm the intestines and does not lead to intestinal bleeding or to any serious disease such as cancer. Most people can control their symptoms with diet, stress management, and medications prescribed by their physician. But for some people, IBS can be disabling. They may be unable to work, go to social events, or travel even short distances.
What causes one person to have IBS and not another? No one knows. Symptoms cannot be traced to a single organic cause. Research suggests that people with IBS seem to have a colon that is more sensitive and reactive than usual to a variety of things, including certain foods and stress. Some evidence indicates that the immune system, which fights infection, is also involved. IBS symptoms result from the following:
Graphic of the body including the mouth, esophagus, colon, small intestine, stomach, reticulum, rectum and anus.
* The normal motility of the colon may not work properly. It can be spasmodic or can even stop temporarily. Spasms are sudden strong muscle contractions that come and go.
* The lining of the colon (epithelium), which is affected by the immune and nervous systems, regulates the passage of fluids in and out of the colon. In IBS, the epithelium appears to work properly. However, fast movement of the colon's contents can overcome the absorptive capacity of the colon. The result is too much fluid in the stool. In other patients, colonic movement is too slow, too much fluid is absorbed, and constipation develops.
* The colon responds strongly to stimuli (for example, foods or stress) that would not bother most people.
In people with IBS, stress and emotions can strongly affect the colon. It has many nerves that connect it to the brain. Like the heart and the lungs, the colon is partly controlled by the autonomic nervous system, which has been proven to respond to stress. For example, when you are frightened, your heart beats faster, your blood pressure may go up, or you may gasp. The colon responds to stress also. It may contract too much or too little. It may absorb too much water or too little.
Research has shown that very mild or hidden (occult) celiac disease is present in a smaller group of people with symptoms that mimic IBS. People with celiac disease cannot digest gluten, which is present in wheat, rye, barley, and possibly oats. Foods containing gluten are toxic to these people, and their immune system responds by damaging the small intestine. A blood test can determine whether celiac disease is present. (For information about celiac disease, see the Celiac Disease fact sheet from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).)
* large meals
* bloating from gas in the colon
* medicines
* wheat, rye, barley, chocolate, milk products, or alcohol
* drinks with caffeine, such as coffee, tea, or colas
* stress, conflict, or emotional upsets
Researchers have also found that women with IBS may have more symptoms during their menstrual periods, suggesting that reproductive hormones can exacerbate IBS problems.
The colon, which is about 5 feet long, connects the small intestine with the rectum and anus. The major function of the colon is to absorb water, nutrients, and salts from the partially digested food that enters from the small intestine. Two pints of liquid matter enter the colon from the small intestine each day. Stool volume is a third of a pint. The difference in volume represents what the colon absorbs each day.
Colon motility (the contraction of the colon muscles and the movement of its contents) is controlled by nerves and hormones and by electrical activity in the colon muscle. Contractions move the contents slowly back and forth but mainly toward the rectum. During this passage, water and nutrients are absorbed into the body. What remains is stool. A few times each day, strong muscle contractions move down the colon, pushing the stool ahead of them. Some of these strong contractions result in a bowel movement. The muscles of the pelvis and anal sphincters have to relax at the right time to allow the stool to be expelled. If the muscles of the colon, sphincters, and pelvis do not contract in a coordinated way, the contents do not move smoothly, resulting in abdominal pain, cramps, constipation or diarrhea, and a sense of incomplete stool movement.
Abdominal pain or discomfort in association with bowel dysfunction is the main symptom. Symptoms may vary from person to person. Some people have constipation (hard, difficult-to-pass, or infrequent bowel movements); others have diarrhea (frequent loose stools, often with an urgent need to move the bowels); and still others experience alternating constipation and diarrhea. Some people experience bloating, which is gas building up in the intestines and causing the feeling of pressure inside the abdomen.
IBS affects the motility or movement of stool and gas through the colon and how fluids are absorbed. When stool remains in the colon for a long time, too much water is absorbed from it. Then it becomes hard and difficult to pass. Or spasms push the stool through the colon too fast for the fluid to be absorbed, resulting in diarrhea. In addition, with spasms, gas may get trapped in one area or stool may collect in one place, temporarily unable to move forward.
Sometimes people with IBS have a crampy urge to move their bowels but cannot do so or pass mucus with their bowel movements.
Bleeding, fever, weight loss, and persistent severe pain are not symptoms of IBS and may indicate other problems such as inflammation or rarely cancer.
If you think you have IBS, seeing your doctor is the first step. IBS is generally diagnosed on the basis of a complete medical history that includes a careful description of symptoms and a physical examination.
No particular test is specific for IBS. However, diagnostic tests may be performed to rule out other diseases. These tests may include stool or blood tests, x rays, or endoscopy (viewing the colon through a flexible tube inserted through the anus). If these tests are all negative, the doctor may diagnose IBS based on your symptoms: that is, how often you have had abdominal pain or discomfort during the past year, when the pain starts and stops in relation to bowel function, and how your bowel frequency and stool consistency are altered.
* Abdominal pain or discomfort for at least 12 weeks out of the previous 12 months. These 12 weeks do not have to be consecutive.
* The abdominal pain or discomfort has two of the following three features:
o It is relieved by having a bowel movement.
o When it starts, there is a change in how often you have a bowel movement.
o When it starts, there is a change in the form of the stool or the way it looks.
No cure has been found for IBS, but many options are available to treat the symptoms. Your doctor will give you the best treatments available for your particular symptoms and encourage you to manage stress and make changes to your diet.
Medications are an important part of relieving symptoms. Your doctor may suggest fiber supplements or occasional laxatives for constipation, as well as medicines to decrease diarrhea, tranquilizers to calm you, or drugs that control colon muscle spasms to reduce abdominal pain. Antidepressants may also relieve some symptoms. Medications available to treat IBS specifically are the following:
* Alosetron hydrochloride (Lotronex) has been re-approved by the U.S. Food and Drug Administration (FDA) for women with severe IBS who have not responded to conventional therapy and whose primary symptom is diarrhea. However, even in these patients, it should be used with caution because it can have serious side effects, such as severe constipation or decreased blood flow to the colon.
* Tegaserod maleate (Zelnorm) has been approved by the FDA for the short-term treatment (usually 4 weeks) of women with IBS whose primary symptom is constipation.
With any medication, even over-the-counter medications such as laxatives and fiber supplements, it is important to follow your doctor's instructions. Laxatives can be habit forming if they are not used carefully or are used too frequently.
It is also important to note that medications affect people differently and that no one medication or combination of medications will work for everyone with IBS. You need to work with your doctor to find the best combination of medicine, diet, counseling, and support to control your symptoms.
Stress--feeling mentally or emotionally tense, troubled, angry, or overwhelmed--stimulates colon spasms in people with IBS. The colon has a vast supply of nerves that connect it to the brain. These nerves control the normal rhythmic contractions of the colon and cause abdominal discomfort at stressful times. People often experience cramps or "butterflies" when they are nervous or upset. But with IBS, the colon can be overly responsive to even slight conflict or stress. Stress also makes the mind more tuned to the sensations that arise in the colon and makes the stressed person perceive these sensations as unpleasant.
Some evidence suggests that IBS is affected by the immune system, which fights infection in the body. The immune system is also affected by stress. For all these reasons, stress management is an important part of treatment for IBS. Stress management comprises
* stress reduction (relaxation) training and relaxation therapies, such as meditation
* counseling and support
* regular exercise such as walking or yoga
* changes to the stressful situations in your life
* adequate sleep
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For many people, careful eating reduces IBS symptoms. Before changing your diet, keep a journal noting the foods that seem to cause distress. Then discuss your findings with your doctor. You may also want to consult a registered dietitian, who can help you make changes to your diet. For instance, if dairy products cause your symptoms to flare up, you can try eating less of those foods. You might be able to tolerate yogurt better than other dairy products because it contains bacteria that supply the enzyme needed to digest lactose, the sugar found in milk products. Dairy products are an important source of calcium and other nutrients. If you need to avoid dairy products, be sure to get adequate nutrients in the foods you substitute or take supplements.
In many cases, dietary fiber may lessen IBS symptoms, particularly constipation. However, it may not help pain or diarrhea. Whole grain breads and cereals, fruits, and vegetables are good sources of fiber. High-fiber diets keep the colon mildly distended, which may help prevent spasms. Some forms of fiber also keep water in the stool, thereby preventing hard stools that are difficult to pass. Doctors usually recommend a diet with enough fiber to produce soft, painless bowel movements. High-fiber diets may cause gas and bloating, but these symptoms often go away within a few weeks as your body adjusts. (For information about diets for people with celiac disease, please see the Celiac Disease fact sheet from NIDDK.)
Drinking six to eight glasses of plain water a day is important, especially if you have diarrhea. But drinking carbonated beverages, such as sodas, may result in gas and cause discomfort. Chewing gum and eating too quickly can lead to swallowing air, which again leads to gas.
Also, large meals can cause cramping and diarrhea, so eating smaller meals more often or eating smaller portions should help IBS symptoms. It may also help if your meals are low in fat and high in carbohydrates, such as pasta, rice, whole-grain breads and cereals (unless you have celiac disease), fruits, and vegetables.
IBS itself is not a disease. As its name indicates, it is a syndrome--a combination of signs and symptoms. But IBS has not been shown to lead to any serious, organic diseases, including cancer. Through the years, IBS has been called by many names, among them colitis, mucous colitis, spastic colon, or spastic bowel. However, no link has been established between IBS and inflammatory bowel diseases such as Crohn's disease or ulcerative colitis.
The NIDDK conducts and supports research into many kinds of digestive disorders, including IBS. Researchers are studying gastrointestinal motility and sensitivity to find possible treatments for IBS. These studies include the structure and contraction of gastrointestinal muscles as well as the mechanics of fluid movement through the intestines. Understanding the influence of the nerves, hormones, and inflammation in IBS may lead to new treatments to better control the symptoms.
* IBS is a disorder that interferes with the normal functions of the colon. The symptoms are crampy abdominal pain, bloating, constipation, and diarrhea.
* IBS is a common disorder found more often in women than in men and usually begins around age 20.
* People with IBS have colons that are more sensitive and react to things that might not bother other people, such as stress, large meals, gas, medicines, certain foods, caffeine, or alcohol.
* IBS is diagnosed by its symptoms and by the absence of other diseases.
* Most people can control their symptoms by taking medicines (laxatives, antidiarrhea medicines, tranquilizers, or antidepressants), reducing stress, and changing their diet.
* IBS does not harm the intestines and does not lead to cancer. It is not related to Crohn's disease or ulcerative colitis.
For More Information
International Foundation for Functional Gastrointestinal Disorders
P.O. Box 170864
Milwaukee, WI 53217
Phone: 1-888-964-2001 or (414) 964-1799
Fax: (414) 964-7176
Email: iffgd@iffgd.org
Internet: www.iffgd.org
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The U.S. Government does not endorse or favor any specific commercial product or company. Trade, proprietary, or company names appearing in this document are used only because they are considered necessary in the context of the information provided. If a product is not mentioned, this does not mean or imply that the product is unsatisfactory.
National Digestive Diseases Information Clearinghouse
2 Information Way
Bethesda, MD 20892-3570
Email: nddic@info.niddk.nih.gov
The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health under the U.S. Department of Health and Human Services. Established in 1980, the clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.
Publications produced by the clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This fact sheet was reviewed by Michael Camilleri, M.D., Mayo Clinic Rochester.
This e-text is not copyrighted. The clearinghouse encourages users of this e-pub to duplicate and distribute as many copies as desired.
NIH Publication No. 03-693
April 2003
The term "irritable bowel syndrome" (often called IBS) refers to a collection of symptoms with no obvious cause. It is not a disease, but a syndrome -- a group of symptoms that occur together. People with IBS seem to have perfectly healthy digestive systems, but they frequently develop cramping pain in the lower abdomen along with either diarrhea or constipation (sometimes alternating bouts of both). Typically, the pain flares up after a meal and goes away after a bowel movement. Many people also experience gas, bloating, small stools, or mucus in the stool. The symptoms tend to come and go and can occur in any combination.
About 10% to 20% of Americans have IBS at some point in their lives, and the symptoms usually start before the age of 50. Women are more likely than men to have the condition.
For many years, doctors thought irritable bowel syndrome was mainly a condition of the mind. After all, these patients always had normal physical exams, and many said they noticed symptoms only during times of stress. Many questions remain, but it's clear that IBS isn't "all in your head." Researchers now suspect the problem springs from a communication breakdown between the nerves and muscles that control the colon.
Without the proper controls, the contractions that move waste through the colon can speed up, leading to painful spasms and diarrhea. Alternatively, the contractions can become sluggish, setting the stage for constipation. The colon also becomes extremely sensitive, and even normal contractions can cause considerable pain.
Stress and anxiety may not cause irritable bowel syndrome, but they can definitely make symptoms worse. Some people also react strongly to certain foods and drinks, especially fatty foods, dairy products, and food or drinks with alcohol or caffeine.
Doctors can usually diagnose irritable bowel syndrome by taking an inventory of a patient's symptoms and performing a physical exam. They may also want to check the blood or stool for other possible causes of the symptoms, such as parasitic infections or diabetes. Some patients, particularly those over age 50, also need to have their colon examined with a sigmoidoscope or colonoscope to rule out colon cancer and other diseases.
Symptoms of irritable bowel syndrome may eventually fade completely for some patients, but most live with it for the rest of their lives. Fortunately, IBS doesn't damage the bowels, and it doesn't raise the risk of colon cancer or any other disease.
There's no single game plan for treating irritable bowel syndrome. IBS is different for everyone but, with your doctor's help, you can find an individual approach that works best for your symptoms. The treatment is focused on controlling, rather than curing, the symptoms of IBS.
First, the more you know about your condition, the more you can do to help yourself. For this reason, it's a good idea to keep a symptom diary for at least a couple of weeks. Every day, write down your symptoms and what you were doing before they started. Also keep track of food, drinks, and emotions. Then look for patterns. If something reliably causes trouble, you can try to avoid it.
You may find that a simple change of diet works wonders. Many people feel better after cutting some fat from their meals. It may also help to reduce caffeine and alcohol. Some people also find that their symptoms get worse with dairy products.
If you are constipated, increasing your fiber intake to 20 grams or 30 grams every day can help keep you regular. Fiber may also help IBS symptoms by lowering the pressure inside the bowels. A high-fiber diet may worsen some symptoms, such as gas, bloating, or stomach pain, so it is good idea to start adding it slowly. Natural food sources of fiber include whole-grain breads and cereals, many fruits and vegetables, and bran. Fiber can also be added to the diet through supplements, like Metamucil and FiberCon.
If your bouts of IBS seem to go hand-in-hand with stress and anxiety, you may need to learn how to relax and cope with your feelings. Ask your doctor about relaxation techniques or counseling.
If necessary, your doctor can prescribe medications to help control your symptoms. The drugs hyoscyamine (Anaspaz, Cystospaz, Levsin) and dicyclomine (Bentyl) can all ease pain and diarrhea by relaxing the colon. Your doctor may also prescribe an antidepressant. Antidepressants can help block pain and may also be useful if you have depression or anxiety along with the IBS.
Lotronex, which affects how the intestines use the chemical messenger serotonin, has received limited approval for women who suffer from the severe form of IBS that causes diarrhea. It is no longer approved for other patients, because some who took Lotronex experienced severe constipation or reduced blood flow to the large intestine (ischemic colitis). In a few cases, side effects led to surgery to correct the problem. In other cases, deaths have been linked to the medication.
The drug Zelnorm has also been approved to treat IBS symptoms in women on a short-term basis. The safety and effectiveness of Zelnorm has not yet been established in men. Studies of Zelnorm show it helps women whose primary IBS symptom is constipation. It works by increasing the movement of stool through the bowels. Use of Zelnorm also reduces bloating as well as pain and discomfort in the abdominal area.
Zelnorm works by mimicking the effects of the naturally occurring chemical called serotonin. Lotronex, in contrast, does essentially the opposite -- it inhibits the action of serotonin.
Over-the-counter medications may be useful, too, but be sure to check with your doctor first before taking them. The drug loperamide (Imodium A-D) may help relieve diarrhea. If you have constipation, you may be able to take over-the-counter laxatives once in a while. Ask your doctor which types, if any, will work for you and how often you can safely take them.
Medically reviewed by Cynthia Haines, MD, July 2004.
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Fiber reduces IBS symptoms--especially constipation--because it makes stool soft, bulky, and easier to pass. Fiber is found in bran, bread, cereal, beans, fruit, and vegetables.
Here are some examples of foods with fiber:
Fruits Vegetables Breads, cereals, and beans
Apples
Peaches Broccoli, raw
Cabbage
Carrots, raw
Peas Kidney beans
Lima beans
Whole-grain bread
Whole-grain cereal
Add foods with fiber to your diet a little at a time to let your body get used to them. Too much fiber all at once might cause gas, which can trigger symptoms in a person with IBS.
Besides telling you to eat more foods with fiber, the doctor might also tell you to get more fiber by taking a fiber pill or drinking water mixed with a special high-fiber powder.
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By Ed Susman Special to DG News SEATTLE, WA -- October 24, 2002 -- For the first time, the American College of Gastroenterology (ACG) issued a monograph that outlines an evidence-based approach to the management of irritable bowel syndrome -- and specifically cites two medications that appear to improve the condition in a majority of patients. "There are drugs that significantly change peoples' lives for the better," said Lawrence Brandt, MD, professor of medicine and surgery at the Albert Einstein College of Medicine, in The Bronx, New York, United States. Dr. Brandt said the monograph produced by the college and discussed at a press briefing here October 22 during the 67th annual scientific meeting of the ACG illustrates that tegaserod, a 5HT4 serotonin receptor agonist is more effective than placebo in relieving global irritable bowl symptoms in women who also have constipation, and that the 5HT3 serotonin receptor antagonist alosetron is more effective than placebo in similar patients who have diarrhoea. Tegaserod is available by prescription as Zelnorm and is marketed by Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, United States. Alosetron is not presently available but is expected to return to the marketplace within the next three months following review by the Food and Drug Administration. Alosetron is expected to be marketed as Lotronex by GlaxoSmithKline, Research triangle Park, North Carolina. "Tegaserod has a very bright future in treatment of irritable bowel syndrome," said Kevin Olden, MD, associate professor of medicine and psychiatry at Mayo Clinic, in Scottsdale, Arizona, United States. He said he expects that the drug will also find utility in other disease states as well. About 60 percent of patients with irritable bowel syndrome respond to tegaserod, he said. The document developed by the ACG Functional Gastrointestinal Disorders Task Force reviewed clinical trials of various treatments for irritable bowel syndrome, a complaint that more often affects women than men and affects 10 percent to 15 percent of the North American population. "Because of the prevalence of this disease it clearly deserves our attention," said Dr. Olden. Among the findings: ---There is insufficient evidence to make a recommendation about the effectiveness of antisposmodic agents. ---Bulking agents are not more effective that placebo at relieving global irritable bowel syndrome symptoms. ---Loperamide is not more effective that placebo at relieving global irritable bowel syndrome symptoms. ---Tricyclic antidepressants improve abdominal pain in irritable bowel syndrome patients. ---Tegaserod is more effective than placebo at relieving global irritable bowel syndrome symptoms in women with constipation. ---Alosetron is more effective than placebo at relieving global irritable bowel syndrome symptoms in women with diarrhoea. ---Behavioural therapy is more effective than placebo at relieving individual irritable bowel syndrome symptoms. The recommendations regarding tegaserod and alosetron were considered Grade A recommendations, the highest level for any of the recommendations. The researchers defined irritable bowel syndrome as abdominal discomfort associated with altered bowel habits. Dr. Brandt noted that the document did not represent treatment guidelines. He said doctors should use the information in the monograph to answer the question: "Are the things that we do so commonly based on reasonable scientific evidence?" He said the information in the document assembled "enough evidence to support or refute what we do." Most people with irritable bowel syndrome who seek medical help fall into three categories, the doctors said: those who have abdominal discomfort accompanied by diarrhoea; those who have abdominal discomfort accompanied by constipation, and those who have alternating constipation and diarrhea
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Targeted Antibiotics Lead to Prolonged Improvement in IBS Symptoms
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LONDON, UK -- October 19, 2006 -- Researchers at Cedars-Sinai Medical Center have found that a nonabsorbable antibiotic -- one that stays in the gut -- can be an effective long-term treatment for irritable bowel syndrome (IBS), a disease affecting more than 20% of Americans. The study, which appears in the October 17 issue of the Annals of Internal Medicine, is the first to demonstrate benefits from antibiotic use even after the course of treatment has ended, supporting previously published research that identified small intestine bacterial overgrowth as a cause of the disease. The randomized, double-blind, placebo-controlled study involved 87 participants, all of whom met specific multinational guidelines for diagnosis of IBS. They received 400 mg of the antibiotic rifaximin three times a day for 10 days or a placebo. Participants completed an extensive symptom questionnaire at the start of the study and then weekly for 10 weeks following treatment. The questionnaire measured the severity of nine symptoms (abdominal pain, diarrhea, constipation, bloating, urgency, incomplete evacuation, mucus, sense of incomplete evacuation, and gas). Patients were also asked to provide a% global improvement from 0 to 100% in their overall IBS symptoms. Researchers found that the rifaximin not only led to significant improvement in global IBS symptoms during the 10 days it was administered, but also that the benefit continued for the 10 weeks of follow up when no antibiotic was given, showing sustained benefit. "The fact that the benefit of the targeted antibiotic continued even after it was stopped provides evidence that the antibiotic was acting on a source of the problem: excess bacteria in the gut," said Mark Pimentel, M.D., director of the GI Motility Program at Cedars-Sinai and the study's principal investigator. "This finding offers a new treatment approach -- and a new hope -- for people with IBS." Irritable Bowel Syndrome is one of the top 10 most frequently diagnosed conditions by U.S. physicians. It is an intestinal disorder that causes abdominal pain, cramping, bloating and diarrhea and/or constipation and is a long-term condition that usually begins in early adult life. Episodes may be mild or severe and may be exacerbated by stress. IBS is more common in women than in men. "While this study being released today demonstrates that the non-absorbed antibiotic rifaximin has great promise in the clinical improvement of IBS, more research is needed," said Pimentel. "Next steps include multi-center studies to further assess short- and long-term benefits of this drug. Tests comparing rifaximin to other types of antibiotics that have been used to treat the disease should also be conducted." Because the cause of IBS has been elusive, treatments for the disease have historically focused on reducing its symptoms – diarrhea and constipation – by giving medications that either slow or speed up the digestive process. In The American Journal of Gastroenterology (Dec. 2000), Pimentel linked bloating, the most common symptom of IBS, to bacterial fermentation by giving lactulose breath tests to participants. The test, which monitors the level of hydrogen and methane (the gases emitted by fermented bacteria) on the breath, showed evidence that small intestine bacteria overgrowth may be a causative factor in IBS. Participants in the current Annals study also took the breath tests, which showed similarly increased levels of hydrogen and methane. Rifaximin, an antibiotic that is FDA-approved for travelers' diarrhea in this country, is made by Salix Pharmaceuticals, Inc. Funding for the study was also provided by Salix. The discovery related to the use of rifaximin for IBS was made at Cedars-Sinai by Pimentel. Cedars-Sinai holds patent rights to this discovery and has licensed rights to the invention to Salix. Other authors from Cedars-Sinai include Sandy Park, James Mirocha, and Yuthana Kong. Sunanda V. Kane from the University of Chicago also participated in the study. SOURCE: Cedars-Sinai Medical Center
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