I’ve always heard that skin sutures should be covered and kept dry for a couple of days in order to prevent infections – at least that’s the usual standard medical advice. But does getting recent sutures wet really lead to more infections?
To answer that question, a couple of years ago a team of Australian researchers randomly assigned over 850 patients who needed skin sutures into one of two groups. Patients in one group were asked to keep their sutures dry and covered, while the patients in the other group were allowed to remove their bandages and get their sutures wet within the first 48 hours.
The results of the study indicated that there were no differences in the incidences of infection between the two groups. The results indicate that it would be perfectly okay to take a shower without increasing the risk of infection of recent skin sutures. But I wouldn't suggest going swimming in a scummy lake or river....
Tampilkan postingan dengan label cells and tissues. Tampilkan semua postingan
Tampilkan postingan dengan label cells and tissues. Tampilkan semua postingan
Selasa, 08 Juni 2010
Sabtu, 17 April 2010
Medical Spas Warned about Lipodissolve
Medical spas are making big bucks on a procedure called lipodissolve, the latest fad for getting rid of unwanted fat. The procedure involves the injection directly into subcutaneous fat deposits of two active ingredients that allegedly break the bonds in the molecular form of stored fat (for more, see Human Biology 5th ed., pp. 94-95.). The active ingredients may also disrupt the cell membranes of fat cells, causing death of the cells. Goodby, fat! But does it work?
In fact, the products used in the lipodissolve procedure have never been evaluated and approved for that purpose by the U.S. Food and Drug Administration (FDA). The safety and efficacy of the lipodissolve procedure is unknown. So this month the FDA sent warning letters to six U.S. medical spas and to a Brazilian firm that advertises the lipodissolve procedure over the internet, warning them to stop making false or misleading statements about the products used in the procedure. The letters warned that assertions that the products used in lipodissolve are safe and effective, have an outstanding safety record, or are superior to other fat-loss procedures are unwarranted and are in violation of the federal FDA Cosmetic act. The companies must take action to correct the violations and to prevent future ones or they will face legal action.
In fact, the products used in the lipodissolve procedure have never been evaluated and approved for that purpose by the U.S. Food and Drug Administration (FDA). The safety and efficacy of the lipodissolve procedure is unknown. So this month the FDA sent warning letters to six U.S. medical spas and to a Brazilian firm that advertises the lipodissolve procedure over the internet, warning them to stop making false or misleading statements about the products used in the procedure. The letters warned that assertions that the products used in lipodissolve are safe and effective, have an outstanding safety record, or are superior to other fat-loss procedures are unwarranted and are in violation of the federal FDA Cosmetic act. The companies must take action to correct the violations and to prevent future ones or they will face legal action.
Kamis, 25 Maret 2010
Re-creating Undifferentiated Cells
People who object to the use of embryonic stem cells (ES cells) for research or for therapeutic purposes continue to hope that induced pluripotent stem cells (iPS cells) might just be the answer. If adult cells could somehow be coaxed back (induced) into a state where they were once again capable of differentiating into all kinds of cells (i.e. were pluripotent), then embryonic stem cells just wouldn’t be needed any more.
Researchers announced several years ago that they had, in fact, found a way to create iPS cells. But are currently available iPS cells just as good as ES cells? In the first side-by-side comparisons of iPS and ES cells, two groups report that they are not. Both groups report that while iPS cells can differentiate into many cell types, they just are not very efficient at it, at least not yet.
The results are a disappointment, perhaps, but don’t count iPS cells out just yet. Scientists are still in the early stages of understanding how to create iPS cells in the first place. As the techniques improve, perhaps they’ll begin to look more and more like ES cells after all. And that would be a scientific advance welcomed by all.
Researchers announced several years ago that they had, in fact, found a way to create iPS cells. But are currently available iPS cells just as good as ES cells? In the first side-by-side comparisons of iPS and ES cells, two groups report that they are not. Both groups report that while iPS cells can differentiate into many cell types, they just are not very efficient at it, at least not yet.
The results are a disappointment, perhaps, but don’t count iPS cells out just yet. Scientists are still in the early stages of understanding how to create iPS cells in the first place. As the techniques improve, perhaps they’ll begin to look more and more like ES cells after all. And that would be a scientific advance welcomed by all.
Sabtu, 24 Oktober 2009
Infertility Patients Favor Stem Cell Research
Most couples that have had to resort to in vitro fertilization (IVF) techniques in order to have a child are in favor of stem cell research. When asked in a national survey what they might choose to do with their frozen embryos left over after they have successfully had a child, 60% reported that they were “somewhat likely” or “very likely” to donate them for stem cell research. In contrast, less than a quarter of the respondents planned to discard their frozen embryos, or expressed a desire to donate them to another couple.
Infertility patients are especially aware of the advances in science that have made it possible for them to have children. Perhaps they are just more grateful than most, but apparently most of them have resolved any internal moral dilemma over what to do with their leftover embryos. It is interesting, however, that most of them would rather donate their embryos to research than to know that their biological child was being raised by another couple.
Infertility patients are especially aware of the advances in science that have made it possible for them to have children. Perhaps they are just more grateful than most, but apparently most of them have resolved any internal moral dilemma over what to do with their leftover embryos. It is interesting, however, that most of them would rather donate their embryos to research than to know that their biological child was being raised by another couple.
Jumat, 03 April 2009
Birth Dating Human Cells
How can scientists determine the age of human cells? How frequently are human cells replaced, if at all?
In 2005 scientists hit upon an ingenious method that takes advantage of a dark period in recent world history - the above-ground testing of nuclear weapons between the mid-1950s and 1963. Nuclear weapons testing resulted in a sharp spike in carbon-14 levels worldwide. The levels peaked in 1967 and have since declined as carbon-14 diffused and equilibrated with the atmosphere, the oceans, and the biosphere. Carbon is incorporated into the chemical components of all new cells, of course, including DNA. It turns out that the carbon-14 levels in nuclear DNA correspond very closely to the atmospheric levels at the time the DNA was synthesized. So by comparing the cells’ nuclear DNA carbon-14 levels to a chart of atmospheric cabon-14 levels each year, one can determine the cells’ birth date.
How does this help us determine cell turnover? Think about it: if all of the cells in a piece of tissue are the same age as the individual, then cells are not being replaced throughout life. But if the average cell age is much younger than the individual, then cell turnover must be relatively high. The scientists who developed the cell-dating technique report that neurons in the cerebral cortex (the most highly developed area of the brain) do not undergo significant replacement throughout life - you’re born with all the cortical brainpower you’re ever going to have. In contrast, cells lining the intestine are replaced frequently.
Reference: "Retrospective Birth Dating of Cells in Humans". Cell 122:133-143, 2005.
In 2005 scientists hit upon an ingenious method that takes advantage of a dark period in recent world history - the above-ground testing of nuclear weapons between the mid-1950s and 1963. Nuclear weapons testing resulted in a sharp spike in carbon-14 levels worldwide. The levels peaked in 1967 and have since declined as carbon-14 diffused and equilibrated with the atmosphere, the oceans, and the biosphere. Carbon is incorporated into the chemical components of all new cells, of course, including DNA. It turns out that the carbon-14 levels in nuclear DNA correspond very closely to the atmospheric levels at the time the DNA was synthesized. So by comparing the cells’ nuclear DNA carbon-14 levels to a chart of atmospheric cabon-14 levels each year, one can determine the cells’ birth date.
How does this help us determine cell turnover? Think about it: if all of the cells in a piece of tissue are the same age as the individual, then cells are not being replaced throughout life. But if the average cell age is much younger than the individual, then cell turnover must be relatively high. The scientists who developed the cell-dating technique report that neurons in the cerebral cortex (the most highly developed area of the brain) do not undergo significant replacement throughout life - you’re born with all the cortical brainpower you’re ever going to have. In contrast, cells lining the intestine are replaced frequently.
Reference: "Retrospective Birth Dating of Cells in Humans". Cell 122:133-143, 2005.
Minggu, 15 Maret 2009
Obama Lifts Stem Cell Ban
Last week President Obama signed an executive order lifting the restrictions on stem cell research laid down by President Bush in 2001 (See the Current Issue in Human Biology 5th. ed., pp. 72-73). Most political analysts expect Congress to enact new legislation soon that will permit federal research dollars to again begin to flow for promising stem cell research projects.
President Obama’s executive order will permit federally funded researchers to use the hundreds of stem cell lines in existence today, as well as new stem cell lines created by private funding in the future. But there is still a prohibition in place, called the Dickey-Wicker Amendment of 1996, which prohibits federal funding for research “in which human embryos are created, destroyed, discarded, or knowingly subjected to risk of injury or death”. So while federally funded researchers will be able to use stem cell lines created by private funds (because they themselves did not destroy any embryos), they will still be prohibited from creating their own new cell lines from human embryos.
How long can the Dickey-Wicker Amendment can stand up in this new climate of stem cell research permissiveness? It's anybody’s guess. The debate continues…
President Obama’s executive order will permit federally funded researchers to use the hundreds of stem cell lines in existence today, as well as new stem cell lines created by private funding in the future. But there is still a prohibition in place, called the Dickey-Wicker Amendment of 1996, which prohibits federal funding for research “in which human embryos are created, destroyed, discarded, or knowingly subjected to risk of injury or death”. So while federally funded researchers will be able to use stem cell lines created by private funds (because they themselves did not destroy any embryos), they will still be prohibited from creating their own new cell lines from human embryos.
How long can the Dickey-Wicker Amendment can stand up in this new climate of stem cell research permissiveness? It's anybody’s guess. The debate continues…
Kamis, 22 Mei 2008
Pet Cloning Goes Commercial
A California biotech company called BioArts plans to hold a public auction to clone five dogs. The scientist involved in the actual cloning will be the South Korean researcher who cloned Snuppy, the male Afghan hound pictured in Human Biology, 5th ed. (p. 418), and who later claimed (fraudulently) to have cloned human embryos.
The auction will be held July 5th through 9th online, with bidding to start at $100,000. The company promises the buyer a puppy that resembles the original dog, guaranteed healthy for a year. The company says that the success rate with cloning dogs has improved to the point that 25% of all embryo transfers now result in a puppy, and that the puppy survival rate is 80%.
Human cloning can’t be far behind. The sticking point is the success rate and the health of the clone – do we really think that a survival rate on the order of 80% would be worth the risk? No one knows the long-term health risks.
The auction will be held July 5th through 9th online, with bidding to start at $100,000. The company promises the buyer a puppy that resembles the original dog, guaranteed healthy for a year. The company says that the success rate with cloning dogs has improved to the point that 25% of all embryo transfers now result in a puppy, and that the puppy survival rate is 80%.
Human cloning can’t be far behind. The sticking point is the success rate and the health of the clone – do we really think that a survival rate on the order of 80% would be worth the risk? No one knows the long-term health risks.
Sabtu, 10 Mei 2008
Fat Cells are Replaced Throughout Life
It is known that every adult has a relatively constant number of fat cells - obese people just tend to have more of them than thin people. When we gain or lose weight our fat cells swell or shrink, but the number of fat cells stays the same. This is one reason why it is so hard for some obese people to lose weight; they are constantly fighting internal homeostatic mechanisms that work to maintain their fat cell's "normal" weight.
But now, researchers have discovered that although you do have a constant number of fat cells throughout life, they are not the same cells. About 10% of them die each year and are replaced by new ones.
No one knows for sure what determines how many fat cells each person has. But the findings open up interesting new avenues for weight control research. If we could determine what regulates the number of fat cells and then alter that regulation, or if we could slow the rate of fat cell division, we might have a new way to fight obesity.
But now, researchers have discovered that although you do have a constant number of fat cells throughout life, they are not the same cells. About 10% of them die each year and are replaced by new ones.
No one knows for sure what determines how many fat cells each person has. But the findings open up interesting new avenues for weight control research. If we could determine what regulates the number of fat cells and then alter that regulation, or if we could slow the rate of fat cell division, we might have a new way to fight obesity.
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