Passage – V

Passage – V

 

Scientists   seeking   new  ways   to  repair   damaged    arteries and  ailing  hearts  have  coaxed  stem  cells  from  a human   embryo into  forming    tiny   blood   vessels.    It’s   the   first   time   human embryonic   stem cells have been  nurtured   to the point  where  they will  organize    into  blood   vessels   that   could   nourish   the  body, according   to Robert  Langer,  leader   of a laboratory    team  at the Massachusetts   Institute  of Technology.   But it isn’t likely to be the last,  as scientists  pursue   research   into  stem  cells despite   debate over  the  ethics  of  using  the  cells.  The new development     was reported   in the  online  issue  of the  proceedings    of the  National Academy   of Sciences.  Dr. John  Gearhart    of the  Johns   Hopkins School  of medicine  said  the  research   was  a “nice  illustration”    of  how  stem  cells can serve  as a source  of various  types  of cells,  in this case for blood  vessels.  “I think this is terrific”, said Gearhart, who was not  a  part   of  the  research    team.   “It’s another    good example   of the isolation   of an important    cell type from human embryonic   stem cells. These are the kinds  of papers  we are going to  see  a lot  of’,  Gearhart   added.   Langer  said  the  work  showed that   endothelial    cells  could  be  made   from  human    embryonic stem   cells.   Endothelial    cells   line   veins,    arteries    and   lymph tissues. They   are   key   to   the    structures     that    carry    blood throughout the  body.  He said  that  if the  technique   was  refined, scientists   could  eventually    be  able  to  make   in  the  laboratory blood  vessels  that  could  be  used  to  replace   diseased   arteries   in the body.  “There  are thousands   of operations   a year  now,  where doctors   take  vessels  from  one  part   of the  body  and  transplant them  to another”,   said  Langer.  Eventually,  he  said,  such vessels might   be  made   outside   the  body   from   embryonic    stem   cells. Langer   said   endothelial     cells  also   might   be   used   to  restore circulation   to the cells damaged   by the heart  attacks.  He said the  processed   stem  cells may  be  able  to  re-establish    blood   flow  to  heart’s   failing   due   to   blocked    arteries.     The   research     was conducted    under   a private   grant,   but  Langer   said  that  the  cell culture  used  in one of 61 worldwide   that  have  been  approved   by the  National   Institute   of Health   for  federally   funded   research. The   use   of   embryonic    stem    cells   is   controversial     because extracting   the  cells kills a living  human   embryo.  President   Bush last  summer   decided   that  federal   funding   would   be  permitted only  for stem  cell cultures   that  already   existed  and  were  made from  embryos  that  were  to be  discarded   by fertility  clinics.  The aim was to prevent   further killing for research  purposes   of other human   embryos.   Langer  said  his lab will seek  federal  money  to continue   research   using  the same  stem  cell cultures,  which  were obtained  from   the   Rambam    Medical   Centre   in  Haifa,   Israel. Embryonic stem  cells are  the  ancestral   cells of every  cells in the body.  In  a  developing    embryo,   they  transform    into  cells that make  up  the  organs,   bone,  skin  and  other  tissues.  Researchers hope to  direct  the  transformation     of  such  cells  to  treat   ailing hearts,   livers,  brains   and   other   organs.   Langer   said  his  team cultured  the   cells  in  such   a  way  that   they   were   allowed   to develop   into  the  various   types   of  cells  that   are  precursors    to mature tissue. From this colony, the researchers extracted cells that were following a linage that would lead to mature endothelial cells. These were further cultured and some eventually formed primitive vascular structure.

1. The readership, that the passage   is intended    for, is most likely to be  :

(a)  health   care  professionals

(b)  doctors

(c) laymen

(d)  stem-cell  researchers

2. Which of the  following   statements    does  not  follow  from the  passage   ?

(a)  Stem  cells are  being  researched   especially  for forming blood  vessels

(b)  Fertility  clinics  collect  human   embryos

(c) Stem  cell research   utilizes  Federal  Funding

(d)  Human   embryos   are destroyed   in stem cell research

3. Endothelial  cells   are   said   to have   all  of  the   following qualities   except  that  :

(a)  they  are  used  to make  blood  vessels

(b)  they  carry  blood  throughout    the  body

(c) they  line veins,  arteries   and  lymph  tissues

(d)  they  are useful  in restoring   circulation   to the  damaged cell

4. Which of the  following   could  be  made   redundant    by the research   mentioned?

(a)  Cardiac  operations   necessitated    by heart  attacks

(b) Transplanting      of   blood    vessels    from   one   part    to another

(c) Sourcing  embryonic   cells from  fertility  clinics

d) Performing open  heart  surgeries

5. Stem cell research   involves   :

(a)  wastage   of embryo  by fertility  clinics

b) cell cultures from  various   genetically-altered     embryos

c) genetic cloning abilities

(d)  killing  of a live human   embryo

 

For answers click on the link below:

Answers