Embryonic stem cells are pluripotent, meaning they are able to grow (i.e.
differentiate) into all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm.
In other words, they can develop into each of the more than 200 cell types of the adult body as long as they are specified to do so stem cells derived from the inner cell mass of an early stage embryo known as a blastocyst. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells.
Embryonic Stem (ES) cells are pluripotent. This means they are able to differentiate into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. These include each of the more than 220 cell types in the adult body. Pluripotency distinguishes ES cells from multipotent progenitor cells found in the adult; these only form a limited number of cell types. When given no stimuli for differentiation, (i.e. when grown in vitro), ES cells maintain pluripotency through multiple cell divisions. The presence of pluripotent adult stem cells remains a subject of scientific debate; however, research has demonstrated that pluripotent stem cells can be directly generated from adult fibroblast cultures.
Stem Cell Research
There has been a lot of discussion about embryonic stem cell research lately. Has the debate left you with questions about the medical potential for control and cures for diseases like Parkinson's, diabetes, and Alzheimer's? Pathologist Michael Shelanski, MD, PhD, joined us on Sept. 22, 2004, to discuss what he and other researchers might find down the stem cell path.
There is also ongoing research to reduce the potential for rejection of the differentiated cells derived from ES cells once researchers are capable of creating an approved therapy from ES cell research. One of the possibilities to prevent rejection is by creating embryonic stem cells that are genetically identical to the patient via therapeutic cloning.
An alternative solution for rejection by the patient to therapies derived from non-cloned ES cells is to derive many well-characterized ES cell lines from different genetic backgrounds and use the cell line that is most similar to the patient; treatment can then be tailored to the patient, minimizing the risk of rejection.
The thing that makes stem cells different is that they are cells that have no defined characteristics and that you can cause to grow in number. So if you start with one stem cell and keep it as a stem cell, over time you can have 10 cells or 10,000 cells. Then by providing the proper signals to those cells you can turn all 10,000 cells into a nerve, a kidney, or pancreas cell.
Therapeutic application
On January 23, 2009, Phase I clinical trials for transplantation of a human-ES-derived cell population into spinal cord-injured individuals received approval from the U.S. Food and Drug Administration (FDA), marking it the world's first human ES cell human trial . The study leading to this scientific advancement was conducted by Hans Keirstead and colleagues at the University of California, Irvine and supported by Geron Corporation of Menlo Park, CA. The results of this experiment suggested an improvement in locomotor recovery in spinal cord-injured rats after a 7-day delayed transplantation of human ES cells that were pushed towards an oligodendrocytic lineage.
Monday, June 29, 2009
Michael Jackson Dies Of Cardiac Arrest
June 25, 2009 -- Pop star Michael Jackson has died at age 50 after suffering a cardiac arrest, according to media reports.
Los Angeles TV station KTLA reports that Los Angeles fire officials said they responded to a 911 call at Jackson's home and that Jackson wasn't breathing when they arrived; paramedics performed CPR and rushed him to UCLA Medical Center, although the hospital, due to privacy rules, could not confirm that.
In a cardiac arrest, the heart stops working properly. A cardiac arrest is not the same as a heart attack, but it can happen because of a heart attack, notes Douglas Zipes, MD, MACC, distinguished professor at Indiana University School of Medicine and past president of the American College of Cardiology.
Zipes explains that "cardiac arrest is a heart rhythm disturbance when the bottom chamber of the heart, the ventricles, beat an at extremely rapid rate -- 4 to 600 times a minute."
Zipes says that heart rhythm "prevents that bottom chamber from effective contraction and pumping blood to the brain and to the rest of the body, and death results if it's not reversed within four or five minutes, generally."
According to his doctor and other physicians, when that heart rhythm disturbance, which is called ventricular fibrillation, happens, the bottom chambers of the heart are "like a bag of squiggly worms without an effective squeeze, and no blood gets pumped to the rest of the body, and without the necessary oxygen in the blood vessels going to the brain, and so on, the brain then begins to die."
Though the family is requesting another autopsy.
Rest in peace michael.
Los Angeles TV station KTLA reports that Los Angeles fire officials said they responded to a 911 call at Jackson's home and that Jackson wasn't breathing when they arrived; paramedics performed CPR and rushed him to UCLA Medical Center, although the hospital, due to privacy rules, could not confirm that.
In a cardiac arrest, the heart stops working properly. A cardiac arrest is not the same as a heart attack, but it can happen because of a heart attack, notes Douglas Zipes, MD, MACC, distinguished professor at Indiana University School of Medicine and past president of the American College of Cardiology.
Zipes explains that "cardiac arrest is a heart rhythm disturbance when the bottom chamber of the heart, the ventricles, beat an at extremely rapid rate -- 4 to 600 times a minute."
Zipes says that heart rhythm "prevents that bottom chamber from effective contraction and pumping blood to the brain and to the rest of the body, and death results if it's not reversed within four or five minutes, generally."
According to his doctor and other physicians, when that heart rhythm disturbance, which is called ventricular fibrillation, happens, the bottom chambers of the heart are "like a bag of squiggly worms without an effective squeeze, and no blood gets pumped to the rest of the body, and without the necessary oxygen in the blood vessels going to the brain, and so on, the brain then begins to die."
Though the family is requesting another autopsy.
Rest in peace michael.
Saturday, June 13, 2009
What is swine flu?
for some weeks now ,the world has been rocked with cases and news of swine flu.so the posts that follows should do justice to this issue by enunciating this topic.
Like people, pigs can get influenza (flu), but swine flu viruses aren't the same as human flu viruses. Swine flu doesn't often infect people, and the rare human cases that have occurred in the past have mainly affected people who had direct contact with pigs. But the current "swine flu" outbreak is different. It's caused by a new swine flu virus that has changed in ways that allow it to spread from person to person -- and it's happening among people who haven't had any contact with pigs. That makes it a human flu virus. In an effort to avoid confusion, the CDC is calling the virus "novel influenza A (H1N1) virus" to distinguish it both from flu viruses that infect mainly pigs and from the seasonal influenza A H1N1 viruses that have been in circulation for many years.
Like people, pigs can get influenza (flu), but swine flu viruses aren't the same as human flu viruses. Swine flu doesn't often infect people, and the rare human cases that have occurred in the past have mainly affected people who had direct contact with pigs. But the current "swine flu" outbreak is different. It's caused by a new swine flu virus that has changed in ways that allow it to spread from person to person -- and it's happening among people who haven't had any contact with pigs. That makes it a human flu virus. In an effort to avoid confusion, the CDC is calling the virus "novel influenza A (H1N1) virus" to distinguish it both from flu viruses that infect mainly pigs and from the seasonal influenza A H1N1 viruses that have been in circulation for many years.
What are symptoms of swine flu?
Symptoms of swine flu are like regular flu symptoms and include fever, cough, sore throat, runny nose, body aches, headache, chills, and fatigue. Many people with swine flu have had diarrhea and vomiting. Nearly everyone with flu has at least two of these symptoms. But these symptoms can also be caused by many other conditions. That means that you and your doctor can't know, just based on your symptoms, if you've got swine flu. Health care professionals may offer a rapid flu test, although a negative result doesn't necessarily mean you don't have the flu.
Only lab tests can definitively show whether you've got swine flu. State health departments can do these tests. But given the large volume of samples coming in to state labs, these tests are being reserved for patients with severe flu symptoms. Currently, doctors are reserving antiviral drugs for people with or at risk of severe influenza.
Only lab tests can definitively show whether you've got swine flu. State health departments can do these tests. But given the large volume of samples coming in to state labs, these tests are being reserved for patients with severe flu symptoms. Currently, doctors are reserving antiviral drugs for people with or at risk of severe influenza.
Who is at highest risk of swine flu
Most U.S. cases of H1N1 swine flu have been in older children and young adults. It's not clear why, and it's not clear whether this will change.
But certain groups are at particularly high risk of severe disease or bad outcomes if they get the flu:
- Pregnant women
- Young children, especially those under 12 months of age
- Elderly people are at high risk of severe flu disease
- People with heart disease or risk factors for heart disease
- People with HIV infection
- People with chronic diseases
- People taking immune-suppressing drugs, such as cancer chemotherapy or anti-rejection drugs for transplants.
How does swine flu spread? Is it airborne?
The swine flu virus can become airborne if you cough or sneeze without covering your nose and mouth, sending germs into the air.
The U.S. residents infected with swine flu virus had no direct contact with pigs. The only way to get the new swine flu is from another person.
How is swine flu treated?
The new swine flu virus is sensitive to the antiviral drugs Tamiflu and Relenza. The CDC recommends those drugs to prevent or treat swine flu; the drugs are most effective when taken within 48 hours of the start of flu symptoms. But not everyone needs those drugs. Most people who have come down with swine flu have recovered without treatment. The Department of Homeland Security has released 25% of its stockpile of Tamiflu and Relenza to states. Health officials have asked people not to hoard Tamiflu or Relenza.
Is there a vaccine against the new swine flu virus?
No. But the CDC and the World Health Organization are already taking the first steps toward making such a vaccine. That's a lengthy process that takes months.
How can I prevent swine flu infection?
The WHO recommends taking these steps:
- Wash your hands regularly with soap and water, especially after coughing or sneezing. Or, use an alcohol-based hand cleaner if soap and water are not available.
- Avoid close contact -- that is, being within six feet -- with people who have flu-like symptoms.
- Avoid touching your mouth, nose, or eyes. That's not easy to do, so keep those hands clean.
- If you have flu-like symptoms -- fever plus at least cough or sore throat or other flu symptoms -- stay home for seven days after symptoms begin or until you've been symptom-free for 24 hours -- whichever is longer.
- The CDC does not recommend using a face mask or respirator in community or home settings. However, the CDC says that people at increased risk of severe flu illness may consider wearing a N-95 respirator or face mask in crowded settings in communities where swine flu is circulating or when taking care of a person with flu-like illness. It's not known whether face masks actually protect against flu transmission.
- People who have or are suspected of having swine flu should wear a face mask, if available and tolerable, when sharing common spaces with other household members, when outside the home, or when breastfeeding.
How long does the flu virus survive on surfaces?
Flu bugs can survive for hours on surfaces. One study showed that flu viruses can live for up to 48 hours on hard, nonporous surfaces such as stainless steel and for up to 12 hours on cloth and tissues. The virus seems to survive for only minutes on your hands -- but that's plenty of time for you to transfer it to your mouth, nose, or eyes.
Can I still eat pork?
yep.
Thats all for now.
Tuesday, June 9, 2009
Chinese Herb Could help Treat immune Diseases
June 4, 2009 -- A drug derived from an herb used in medicines used in china for 2,000 years is the first to target specific cells that are overactive in rheumatoid arthritis, psoriasis, and other autoimmune diseases.
The ancient herb is chang shan, from the root of the blue evergreen hydrangea. It's been used in Chinese medicine to reduce fever and fight malaria.
The herb's active compound, febrifugine, is too toxic for use as a modern drug. In the 1960s, U.S. Army scientists created a febrifugine derivative called halofuginone as a possible malaria drug, but further study was soon discontinued.
More recently, halofuginone was found to reduce skin collagen and was tested as a possible treatment for scleroderma. But until now, nobody knew how the drug worked.
That may be because the drug's target -- a specific kind of immune cell called a Th17 cell -- was identified only in 2006. But now Harvard Medical School researchers Mark S. Sundrud, PhD, Anjana Rao, PhD, and colleagues show that halofuginone does indeed inhibit Th17 cells.
That's important, because Th17 cells regulate autoimmune inflammatory responses. That's the kind of immune response that goes haywire in a wide range of diseases such as inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, type 1 diabetes, eczema, and psoriasis.
"Halofuginone may herald a revolution in the treatment of certain types of autoimmune and inflammatory diseases," i found out in a news release.
That may be because the drug's target -- a specific kind of immune cell called a Th17 cell -- was identified only in 2006. But now Harvard Medical School researchers Mark S. Sundrud, PhD, Anjana Rao, PhD, and colleagues show that halofuginone does indeed inhibit Th17 cells.
That's important, because Th17 cells regulate autoimmune inflammatory responses. That's the kind of immune response that goes haywire in a wide range of diseases such as inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, type 1 diabetes, eczema, and psoriasis.
"Halofuginone may herald a revolution in the treatment of certain types of autoimmune and inflammatory diseases," Rao says in a news release.
Why? Current drugs for autoimmune diseases take a sledgehammer approach. They smash down many different immune responses, leaving patients vulnerable to infections and cancers.
A drug that can specifically inhibit one type of immune response would be a major breakthrough. Halofuginone may turn out to be such a drug.
"This is really the first description of a small molecule that interferes with autoimmune pathology but is not a general immune suppressant," Sundrud says in the news release.
An added bonus: Halofuginone could probably be taken orally, rather than by injection.
Yet the findings by Sundrud and Rao are based only on mouse studies. They must be refined and confirmed in humans before any actual drug is developed.
The ancient herb is chang shan, from the root of the blue evergreen hydrangea. It's been used in Chinese medicine to reduce fever and fight malaria.
The herb's active compound, febrifugine, is too toxic for use as a modern drug. In the 1960s, U.S. Army scientists created a febrifugine derivative called halofuginone as a possible malaria drug, but further study was soon discontinued.
More recently, halofuginone was found to reduce skin collagen and was tested as a possible treatment for scleroderma. But until now, nobody knew how the drug worked.
That may be because the drug's target -- a specific kind of immune cell called a Th17 cell -- was identified only in 2006. But now Harvard Medical School researchers Mark S. Sundrud, PhD, Anjana Rao, PhD, and colleagues show that halofuginone does indeed inhibit Th17 cells.
That's important, because Th17 cells regulate autoimmune inflammatory responses. That's the kind of immune response that goes haywire in a wide range of diseases such as inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, type 1 diabetes, eczema, and psoriasis.
"Halofuginone may herald a revolution in the treatment of certain types of autoimmune and inflammatory diseases," i found out in a news release.
That may be because the drug's target -- a specific kind of immune cell called a Th17 cell -- was identified only in 2006. But now Harvard Medical School researchers Mark S. Sundrud, PhD, Anjana Rao, PhD, and colleagues show that halofuginone does indeed inhibit Th17 cells.
That's important, because Th17 cells regulate autoimmune inflammatory responses. That's the kind of immune response that goes haywire in a wide range of diseases such as inflammatory bowel disease, rheumatoid arthritis, multiple sclerosis, type 1 diabetes, eczema, and psoriasis.
"Halofuginone may herald a revolution in the treatment of certain types of autoimmune and inflammatory diseases," Rao says in a news release.
Why? Current drugs for autoimmune diseases take a sledgehammer approach. They smash down many different immune responses, leaving patients vulnerable to infections and cancers.
A drug that can specifically inhibit one type of immune response would be a major breakthrough. Halofuginone may turn out to be such a drug.
"This is really the first description of a small molecule that interferes with autoimmune pathology but is not a general immune suppressant," Sundrud says in the news release.
An added bonus: Halofuginone could probably be taken orally, rather than by injection.
Yet the findings by Sundrud and Rao are based only on mouse studies. They must be refined and confirmed in humans before any actual drug is developed.
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