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#1 Anduril

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Posted 28 January 2008 - 02:14

Proslog novembra su objavljena dva naucna rada u kojima su po prvi put ljudski kozni fibroblasti reprogramirani u embrionalno stanje:

Human skin 'reprogrammed' to form stem cells

At last, a milestone in stem-cell technology has been reached that could enable patients to be treated with new tissues made from their own cells.

Crucially, the tissues can be generated without having to extract cells from human embryos, a major ethical objection that has obstructed stem cell research until now.

One team in Japan, and another in the US, have independently shown it is possible to produce embryonic-like stem cells directly from a patient's own skin cells without having to create and destroy a cloned human embryo first. Dolly, the most famous sheep in the world, was created using the embryonic method.

Instead, they simply exposed human skin cells to four natural gene switches, called transcription factors. Both teams successfully used these to reprogramme skin cells in a lab dish into cells resembling embryonic stem cells, which have the ability to turn into any tissue of the human body.

Both teams used viruses to insert four genes comprising the transcription factors into skin cells, and demonstrated that brain, heart and other tissues could be created from cells created this way.

Virus hurdle

"We are now in a position to be able to generate patient- and disease-specific stem cells, without using human eggs or embryos," says Shinya Yamanaka of the University of Kyoto, who led the Japanese team. "These cells should be useful in understanding disease mechanisms, searching for effective and safe drugs, and treating patients with cell therapy."

For these cells to be as useful as embryonic stem cells, "we have to find a way to avoid retroviruses before application in cell therapy", Yamanaka says, as they could result in tumours.

The US team, led by James Thomson of the Genome Center of Wisconsin in Madison, reported their breakthrough in the journal Science.

'Scientific milestone'

"This work represents a tremendous scientific milestone," says Bob Lanza, chief scientist at Advanced Cell Technologies in Massachusetts, US. "But this isn't over by a long shot. It's extremely important to temper the excitement with caution."

Lanza says success will depend on be finding alternative ways to create such cells: "The FDA would never allow us to use these virally modified cells in patients."

"Having two ways to re-programme might help us understand how reprogramming works," adds Robin Lovell-Badge of the National Institute of Medical Research in London. "But we should be careful not to abandon embryo research altogether. It's always best to keep all avenues of research open to maximise chances of success."

Journal references: Cell (DOI: 10.1016/j.cell.2007.11.019), Science (DOI: 10.1126/science.1151526)


Istovremeno naucnici rade i na tome da se uz pomoc tih embrionalnih staminalnih celija u in vitro uslovima metodologijom diferencijacije dobiju razna tkiva - kao recimo u ovom slucaju srcano:

Human heart tissue grown from stem cells
13:20 02 April 2007
NewScientist.com news service
Andy Coghlan
Part of a human heart has been grown from stem cells for the first time, a UK research team has announced. The small discs of tissue could represent the first step towards building a whole heart from stem cells.

The 3-centimetre-wide discs are made from the same tissue as heart valves, and the team which created them at the Harefield Heart Science Centre near London hopes to test prototypes of valves in animals later this year.

The stem cells – extracted from bone marrow – were exposed to various chemicals in the lab which caused them to differentiate into heart valve cells. These were then grown into discs over scaffolds of collagen – the connective tissue in limbs and organs.

Led by heart surgeon Magdi Yacoub, the team told Guardian newspaper that the full results will be published in August in the journal Philosophical Transactions of the Royal Society B.

Animal trials are planned for later this year and, if successful, replacement tissue could be used in transplants for people suffering from heart disease within three years, they said.

“Like everything published ahead of time, it’s hard to work out exactly what they’ve done,” said Stephen Minger, a stem cell scientist at King’s College London in the UK. Yacoub told the newspaper that similar valves could be fitted in patients within five years, but it would take at least 10 years to build an entire heart.


Potencijal ove metodologije je naravno ogroman i mnogi su vec uocili da se potencijalno nalazimo na pragu nove biolosko-medicinske revolucije.

#2 seca

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Posted 08 February 2008 - 13:18

koliko ja znam , to za srce se vec radi,kao i za druga tkiva ,ali u svet...

#3 Schrodinger

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Posted 11 February 2008 - 18:36

Pa, to je svakako ongoing revolucija, i mogu se ocekivati zaista veliki rezultati i znacajno produzenje ljudskog zivota - samo dok je razni ideoloski lobiji (sto verski, sto deep-ekoloski, sto tradicionalisticki) i njihova ludacko-teroristicka krila ne zaustave...

#4 seca

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Posted 11 February 2008 - 19:44

a znas kako ... kad su prvi put presadjivali srce ,te doktore su gledali ko ludake...

#5 Anduril

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Posted 11 February 2008 - 23:07

Pa, to je svakako ongoing revolucija, i mogu se ocekivati zaista veliki rezultati i znacajno produzenje ljudskog zivota - samo dok je razni ideoloski lobiji (sto verski, sto deep-ekoloski, sto tradicionalisticki) i njihova ludacko-teroristicka krila ne zaustave...


Problem je samo u tome sto se neprestano pravi hype oko staminalnih celija, a istina je da naucnici jos ne razumeju ni osnovne procese u njima, ali zato se vec uveliko rade klinicke studije itd. Slicna situacija je bila i sa genetskom terapijom, a pre toga posle otkrica onkogene u supresora, ali se ipak pokazalo da je put do koriscenja ove tehnologije jos uvek veoma dugacak jer i dalje ne razumemo u dovoljnoj meri neke osnovne celijske procese.

#6 Schrodinger

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Posted 13 February 2008 - 01:54

Problem je samo u tome sto se neprestano pravi hype oko staminalnih celija, a istina je da naucnici jos ne razumeju ni osnovne procese u njima, ali zato se vec uveliko rade klinicke studije itd. Slicna situacija je bila i sa genetskom terapijom, a pre toga posle otkrica onkogene u supresora, ali se ipak pokazalo da je put do koriscenja ove tehnologije jos uvek veoma dugacak jer i dalje ne razumemo u dovoljnoj meri neke osnovne celijske procese.

Naravno, sasvim tacno, ali hajde da izadjemo sa stvari nacistac: ako stvar ne poznajemo dovoljno, onda to nije razlog za obustavljanje istrazivanja, vec pre na intenziviranje istih. E sad, ovu jednostavnu istinu ne shvata ili ne zeli da shvati 90+% populacije u cak i najrazvijenijim zemljama sveta, koja sledi svoju gut reakciju da kad je nesto "nedovoljno poznato", onda od toga treba bezati. I, naravno, demagozi raznih boja to itekako vesto koriste, na celu sa raznim "predstavnicima naroda". Istorija ideja jasno pokazuje da nije, recimo, ni termodinamika bila sasvim poznata sve negde do Bolcmana i Gibsa (dakle tri cetvrti veka ili tako nesto nakon prvih industrijskih parnih masina), a to ipak nije sprecilo, pa cak ni bitno odlozilo industrijsku revoluciju.

I, naravno, najjaci argument je upravo u tome sto bi svako istrazivanje bilo *bezbednije* ako bi se u njega ulozila velika sredstva, a mnogo manje je bezbedno kad se radi u polulegalnim ili ilegalnim uslovima, u privatnoj reziji, u off-shore oazama, itd. isl. Dakle, ko se brine - opravdano! - za rizike koji iz toga proisticu bi trebalo, ako hoce da bude logican, da se bori za *povecanje* ulaganja u biotech i slicne stvari. Ali, ljudska bica nisu bas logicna i racionalna...

#7 Anduril

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Posted 29 February 2008 - 01:16

Naravno, sasvim tacno, ali hajde da izadjemo sa stvari nacistac: ako stvar ne poznajemo dovoljno, onda to nije razlog za obustavljanje istrazivanja, vec pre na intenziviranje istih. E sad, ovu jednostavnu istinu ne shvata ili ne zeli da shvati 90+% populacije u cak i najrazvijenijim zemljama sveta, koja sledi svoju gut reakciju da kad je nesto "nedovoljno poznato", onda od toga treba bezati. I, naravno, demagozi raznih boja to itekako vesto koriste, na celu sa raznim "predstavnicima naroda". Istorija ideja jasno pokazuje da nije, recimo, ni termodinamika bila sasvim poznata sve negde do Bolcmana i Gibsa (dakle tri cetvrti veka ili tako nesto nakon prvih industrijskih parnih masina), a to ipak nije sprecilo, pa cak ni bitno odlozilo industrijsku revoluciju.

I, naravno, najjaci argument je upravo u tome sto bi svako istrazivanje bilo *bezbednije* ako bi se u njega ulozila velika sredstva, a mnogo manje je bezbedno kad se radi u polulegalnim ili ilegalnim uslovima, u privatnoj reziji, u off-shore oazama, itd. isl. Dakle, ko se brine - opravdano! - za rizike koji iz toga proisticu bi trebalo, ako hoce da bude logican, da se bori za *povecanje* ulaganja u biotech i slicne stvari. Ali, ljudska bica nisu bas logicna i racionalna...


Slazem se - ako nesto ne poznajemo, to je je samo razlog vise da intenziviramo istrazivanja na tome i smanjimo nepoznanice. Medjutim, cesto medju naucnicima postoji i sindrom "da mi zapravo uglavnom sve vec znamo", tj. da su sva velika otkrica vec napravljena, a da su ostali samo detalji, pa prilicno arogantno krecu u neke opasne avanture sa primenom tog nekompletnog znanja u problematicnim oblastima (medicina npr.). No cinjenica je, da su pojedine naucne discipline toliko razvijene (recimo biologija), da je nemoguce obuhvatiti sve oblasti zbog ogromnog broja razlicitih mehanizama i principa funkcionisanja.