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18-07-03, 19:17
Immune 'invisibility' of brain stem cells proven
17:10 18 July 03
NewScientist.com news service

Stem cells from the brain do not provoke an immune response when transplanted to different parts of another individual's body, suggests a study in mice.

The finding could help overcome immune rejection, one of the most difficult obstacles to developing therapies to treat people with central nervous system problems such as spinal cord injuries and Parkinson's disease.

Michael Young, at the Schepens Eye Research Institute, Harvard, and US and Japanese colleagues have shown that stem cells from the brain have a special "immune privilege" even when they are transplanted to places outside their normal location in the central nervous system.

The team found that stem cells transplanted from the brains of mice to the kidney capsules of mice of a different strain not only survived, but developed into mature tissue.

"These findings are very exciting," says Young. "Though we suspected brain stem cells might be protected in this way, this is the first documented evidence."

The study is "encouraging" says Douglas Kerr, a neurobiologist at Johns Hopkins University in Baltimore, Maryland, who is researching applications of embryonic stem cells in spinal cord injury. If the results are reproducible "it would certainly make a human application more likely", he told New Scientist.

Stern test

Special sites within the body are known to have "immune privilege". The body's immune system does not mount an attack against foreign invaders in these areas - which includes the eye, brain and reproductive system - as these tissues are so delicate that inflammation caused by a response would destroy their function.

As a stern test of the immune properties of stem cells from the brain, the team transplanted the cells to a part of the body - the kidney capsule - known to always reject foreign tissue unless the tissue is closely matched or immunosuppressant drugs are given.

Stem cells were taken from the brains of so-called "green mice" which have a jellyfish gene for a green protein inserted in their DNA. These were then transplanted to the kidney capsules of normal mice.

The green cells were not rejected in any of the mice after four weeks, and in fact had grown into neural tissue. But Young told New Scientist that the team were not surprised at this: "We really anticipated that these were going to be really cool cells from an immunological perspective."

Identity tag

What did surprise the team was that further tests revealed that even though the stem cells had antigens on their surface - molecules which should have identified them as foreign - they appeared to be invisible to the immune system.

Stem Cells

"These really have important implications for the ultimate success of stem cell transplantation," Young says.

Kerr agrees that tackling immunosuppression is key. He says that people with CNS disorders like stroke or spinal injury are already more susceptible to infection. "This is a high risk population to immunosuppress, so it's really been a barrier in terms of human trials," he told New Scientist.

Another type of immune privileged stem cell is being investigated by Osiris Therapeutics in Baltimore and others (New Scientist print edition, 15 December 2001). These are called "mesenchymal stem cells" (MSCs) and are taken from bone marrow. These cells have been shown to develop into six kinds of tissue, including bone, cartilage, tendon and muscle but not the neural cells that Young's team studied.

Journal reference: Stem Cells (vol 21, p 405)

Shaoni Bhattacharya


18-07-03, 19:33
Your wish is my command :p

18-07-03, 20:07
Lol Barfly :D

De stemming stijgt, het niveau daalt... :wijs:

18-07-03, 20:42
Geplaatst door mrz
Lol Barfly :D

De stemming stijgt, het niveau daalt... :wijs:


Deze dan:

De Australische krant The Age schrijft dat op 27 juli een wetenschappelijke conferentie gehouden zal worden waarbij de mogelijkheid op buitenaards intelligent leven onderzocht wordt. The Hidden Truth Conference wordt georganiseerd door the Australian Close Encounter Network en zal verschillende onderwerpen omtrent buitenaardse levensvormen behandelen, waaronder buitenaardse ontvoeringen.

Mary Rodwell van ACERN heeft met meer dan 800 mensen in Perth een persoonlijk gesprek gehad, die zeiden dat ze contact gehad hebben met buitenaardse wezens. Er worden ook videobeelden getoond van operaties waarbij buitenaardse implantaten verwijderd worden. Dr. Roger Leir zegt dat hij implantaten bij twaalf mensen verwijderd heeft, en dat deze implantaten wetenschappelijk onderzocht zijn. De implantaten vertonen buitengewone overeenkomsten volgens Leir. In bepaalde gevallen werden de implantaten verplaatst toen geprobeerd was deze te verwijderen, aldus Leir. De implantaten zullen ook getoond worden.

Er zal ook gediscussieerd worden over de theorie dat een generatie van mens-alien hybriden, met een hoge graad van intelligentie en sterkte worden geboren door buitenaardse toedracht. Ook zal er gediscussieerd worden over een onbekend verloren beschaving in AustraliŽ, en een persoonlijke belevenis van een lerares uit Nieuw Zeeland die beweert dat ze in een ruimteschip van buitenaardse oorsprong gevlogen heeft.

De nieuwsposter is niet verantwoordelijk voor de inhoud van dit nieuwsbericht uit The Age. Klachten kunnen in Feedback.


Vooral dat implantaten verhaal vind ik wel aardig :)

18-07-03, 22:45
Ik wil niet al te betweterig zijn maar was er niet iets met dromen over vliegen en behoefte aan ...?

Implantaten? Amalgaamvullingen en pacemakers enzo? :P Haha

0.00 MicroSv wordt ik vaak wel happy van, maar het ligt er maar net aan... :moe:

Geiger counter in every human revealed
09:45 03 June 03
Exclusive from New Scientist Print Edition. Subscribe and get 4 free issues.

How much damage does cosmic radiation do to frequent flyers? Is depleted uranium from shells causing cancers in former war zones such as Kosovo and Iraq? The discovery that certain kinds of radiation leave a distinctive pattern of damage in our cells could help answer these questions.