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nana 27 -> RE: Shranjevanje izvornih celic (18.5.2007 15:12:08)
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Tole pa sem našla jaz: Re: izvorne celic
Napisal: Stanko Puđenjak
Datum: 06.04.2007 17:00
Spoštovani,
včasih se vprašanje izmuzne urejevalniku in se kar "samo objavi" mimo mene....:-)
No, na kratko menim, da je za zdaj shranjevanje matičnih celic iz popkovne krvi še precej "tvegana naložba", ker ima že zelo malo konkretne uporabne vrednosti, res pa je, da se obetajo številne nove, za katere pa nihče ne more jamčiti. Zlasti sta dva pomembna problema, ki še nista razjasnjena:
- kako dolgo lahko zamrznjene celice ostanejo vitalne oziroma uporabne
- če je teh celic iz popkovnice dovolj tudi za odraslega človeka ali samo za otroka
Glavno prednost ta oblika "naložbe" predstavlja osebam, ki imajo v druţini povečano pojavnost rakavih obolenj krvotvornih organov, za ostale je to čista loterija, saj je verjetnsot da naključno osebo doleti takšno obolenje v otroštvu manj kot 1:5000.
Pa še:
Umbilical Cord Blood Stem Cell TechnologySoren Müller Bested, CordLife, Singapore
Chris - What's the motivation behind banking umbilical cord stem cells?
Soren - We learnt a few decades back that developing babies do not have any bone marrow, and that all of the stem cells that are responsible for producing bone marrow later in life are found circulating in the blood. So the blood of a new born baby has about ten times the concentration of stem cells that you find in the bone marrow. The idea is that if we can collect umbilical cord blood (after the baby is born), we can harvest the stem cells in the blood and use them as a replacement for bone marrow in a transplant situation. The blood is collected after the baby is born from an umbilical cord that would otherwise be thrown away. We cryogenically preserve the cells at minus 196 degrees Celsius under liquid nitrogen. Evidence suggests that if stored in this way, the stem cells should last indefinitely, although this is hard to prove. Researchers have shown, however, that, when stored in this way, the cells are just as viable after 15-20 years as the day they were first collected.
Chris - Say I have a condition that stem cells can treat. How would you treat me with your stored stem cells?
Soren - We would treat you in a similar way to how we treat a patient with bone marrow stem cells. You would undergo a course of chemotherapy to get rid of the diseased bone marrow in your body. We would then take out the umbilical cord cells that were stored earlier in life and infuse the cells into a vein. The cells circulate in the bloodstream for a short while before they home in on the bone marrow cavity, settle, and begin to produce a new bone marrow. This is exactly the same as in a new born baby. It also means that if you had cells from a female umbilical cord, you would have a female bone marrow for the rest of your life.
Huseyin - People are making huge claims about umbilical cord stem cells. It sounds like Cord Life is a big business and is sincere in what it is doing. What's your current thinking that we could take umbilical cord stem cells and make any tissue you like in the body?
Soren - I think it has a higher potential than we ascribe to it today. However, I don't think cord blood cells will make everything. We restrict ourselves to heart disease and bone marrow disease at the moment.
Chris - One of the constraints is that you only get a small number of stem cells from each umbilical cord. It's not enough to cure an adult. What technology do you have to help solve that problem?
Soren - We realise that this is a problem. We are currently about to start clinical trials on trying to grow umbilical cord stem cells. We are using what is known as the Cytomatrix technology. This technology was originally developed by NASA and is a material with a very large surface area to volume ratio. It was being used in space shuttle catalytic converters. When we looked at the material, we realised that the matrix looked very much like human bone marrow. The thinking was that if we could put the cells in an environment like they are used to, we might be able to expand the cells. We found that it worked. Laboratory and animal tests have been done and we are now at the point where we about to enter human clinical trials. We hope the clinical trails will finish in the next two years, so it will probably be about three to five years before this will become a standard therapy.
pa tole:
Stem cell bank may hold cures of the future
By Roger Highfield, Science Editor
Last Updated: 12:35am GMT 04/02/2007
Video: Virgin stem cell bank
A bank to store stem cells from newborn babies was launched yesterday by Sir Richard Branson.
Flexible cells from umbilical cord blood can already provide life-saving transplant treatments for blood cancers and immune disorders.
The thinking behind the Virgin Health Bank is that developments in tissue regeneration technology in the next decade may also allow the use of an individual's stored cord blood stem cells to grow replacement cells and tissues if and when they are needed.
Sir Richard's scheme is a radical venture for his business empire. It will provide a dual private/public service from its own freezers set up at an existing bank run by the company BioVault in Plymouth.
Each stored sample will be divided and placed in two banks, one (20 per cent of the blood) for the child's personal use, which is unlikely to be used in the short term, and the remaining 80 per cent used in a public bank to make donated cells freely available to anyone who needs them.
Parents will be asked to pay Ł1,500 to collect their child's umbilical cord blood stem cells, which is competitive with the cost of the handful of existing private cord banks. In return they will have a store of cord stem cells as an insurance policy that might benefit their child in the future.
What is unique is that other patients worldwide will also have access to banked, tissue-matched stem cells. The only charge will be for transport, since it is illegal to charge for human tissue.
"Virgin Health Bank has an important role to play in making more of these special cells available," said Sir Richard.
"We all know that the NHS has limited funds and can only do so much – in fact I was visited by a senior professor who is very involved in the NHS collection service and it was clear that the main problem is the lack of stem cells." He added that he wants to launch similar banks worldwide.
The scheme is funded by around Ł10 million from Merlin Biosciences, the venture capital fund set up by Sir Chris Evans, the scientist/entrepreneur who sits on the board of Virgin Health Bank.
The Virgin brand is considered to be worth the same, so half the profits will go to Virgin. Sir Richard said he would give his profits to charities such as the Anthony Nolan Trust involved in treating leukaemia. But the chief executive officer of the bank, Andrew Davis, emphasised:"This is a business. We are not saying we are a charity."
Ian Gibson MP, the former chairman of the Commons science and technology committee, gave a qualified welcome. "It sounds really good but when you get into the details there are some murky corners that need to be divulged," he said.
Success or failure may lie in the hands of NHS managers.
Prof Nicholas Fisk, of Imperial College London, said collecting cord blood was "a real pain", being an unwelcome distraction in caesareans and other complex births, given that collection methods vary among cord blood companies.
To date, there has been "little scientific validity" for private banking. More than half of maternity units refuse to bank blood. Virgin should provide additional staffing to ensure success, he added.
Prof Fisk also warned that in a child's early years their own stem cells are unlikely to help them if they have a condition such as leukaemia, unlike healthy donated cells. The chance of using cord blood for your own baby was "almost nil", he added.
Where Virgin's plan was unusual was making some of each donation of cord blood available for use by others because, unlike bone marrow, cord stem cells do not have to be a perfect match to take.
"Public cord banking is a very laudable aim and they are doing it in a clever way by mixing private and public usage," said Prof Fisk. Virgin said it would rely on the 20 per cent of hospitals who have an existing policy of storing cord blood for its supplies.
A spokesman for the Royal College of Obstetricians and Gynaecology said: "It is imperative that the collection should not in any way compromise the attention of the carers to the delivery, and ideally the sample should be collected by a trained third party."
Belinda Phipps, the chief executive of the National Childbirth Trust, said: "The evidence does not show benefits for the baby.
"The method recommended and used by many commercial companies to collect stem cells risks interrupting the birth process."
Našla sem zelo dober članek v nemščini:
http://www.eltern.de/schwangerschaft_geburt/geburt/nabelschnurblut.html
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