两澳大利亚人获诺贝尔医学奖(3)

In  1982,  when  this  bacterium  was  discovered  by  Marshall  and  Warren,  stress  and  lifestyle  were  considered  the  major  causes  of  peptic  ulcer  disease.  It  is  now  firmly  established  that  Helicobacter  pylori  causes  more  than  90%  of  duodenal  ulcers  and  up  to  80%  of  gastric  ulcers.  The  link  between  Helicobacter  pylori  infection  and  subsequent  gastritis  and  peptic  ulcer  disease  has  been  established  through  studies  of  human  volunteers,  antibiotic  treatment  studies  and  epidemiological  studies.

Helicobacter  pylori  causes  life-long  infection

Helicobacter  pylori  is  a  spiral-shaped  Gram-negative  bacterium  that  colonizes  the  stomach  in  about  50%  of  all  humans.  In  countries  with  high  socio-economic  standards  infection  is  considerably  less  common  than  in  developing  countries  where  virtually  everyone  may  be  infected.

Infection  is  typically  contracted  in  early  childhood,  frequently  by  transmission  from  mother  to  child,  and  the  bacteria  may  remain  in  the  stomach  for  the  rest  of  the  person's  life.  This  chronic  infection  is  initiated  in  the  lower  part  of  the  stomach  (antrum).  As  first  reported  by  Robin  Warren,  the  presence  of  Helicobacter  pylori  is  always  associated  with  an  inflammation  of  the  underlying  gastric  mucosa  as  evidenced  by  an  infiltration  of  inflammatory  cells.

The  infection  is  usually  asymptomatic  but  can  cause  peptic  ulcer

The  severity  of  this  inflammation  and  its  location  in  the  stomach  is  of  crucial  importance  for  the  diseases  that  can  result  from  Helicobacter  pylori  infection.  In  most  individuals  Helicobacter  pylori  infection  is  asymptomatic.  However,  about  10-15%  of  infected  individuals  will  some  time  experience  peptic  ulcer  disease.  Such  ulcers  are  more  common  in  the  duodenum  than  in  the  stomach  itself.  Severe  complications  include  bleeding  and  perforation.

The  current  view  is  that  the  chronic  inflammation  in  the  distal  part  of  the  stomach  caused  by  Helicobacter  pylori  infection  results  in  an  increased  acid  production  from  the  non-infected  upper  corpus  region  of  the  stomach.  This  will  predispose  for  ulcer  development  in  the  more  vulnerable  duodenum. (责任编辑：泉水)

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两澳大利亚人获诺贝尔医学奖(3)