Effects of Helicobacter pylori on proliferation of gastric epithelial cells in vitro.

OBJECTIVE: H. pylori infection of the gastric mucosa has been associated with an increase in gastric epithelial cell proliferation. However, in vitro adherence of H. pylori to gastric epithelial cells is associated with reduced cell proliferation. Reduction of epithelial cell proliferation may contribute to ulcer formation and delay ulcer healing. The following study was undertaken to elucidate the ability of cagA-positive and -negative strains to impede gastric epithelial cell proliferation. METHODS: A human gastric adenocarcinoma cell line (AGS) was overlaid with either cagA-positive or cagA-negative H. pylori strains suspended in cell culture medium. Proliferation of AGS cells was analyzed by performing direct cell counts and by measuring metabolism of a soluble tetrazolium compound (MTS), after exposure to H. pylori for 24 h. RESULTS: When compared with control cells cultured in medium alone, AGS cell proliferation was reduced by 45.6% and 28.5% due to exposure to cagA-negative and cagA-positive strains, respectively. When bacterial-induced cytotoxicity was assessed by measuring release of lactose dehydrogenase (LDH) into the culture medium, cagA-positive strains were shown to induce significantly more cytotoxicity than cagA-negative strains. CONCLUSIONS: These experiments demonstrate that H. pylori exposure to AGS cells significantly reduces cell proliferation. However, cagA-positive strains that induce more cell injury reduce cell proliferation to a lesser extent than cagA-negative strains. Persistent replication of gastric epithelial cells injured by exposure to cagA-positive strains may be partially responsible for the stronger association with gastric cancer in persons infected with cagA-positive H. pylori strains.

Remarks on gastroenterologic diagnostics of amoebic liver abscess, peritoneal tuberculosis and tropical splenomegaly.

The amoebic liver abscess, the peritoneal tuberculosis and the "tropical splenomegaly" belong to diseases which are frequent in warm countries but single cases appear also in moderate climate by intercontinental communications. False diagnoses especially in the first both can lead to severe rsp. fatal consequenses. Therefore experiences are dealed with, which have been gained within nearly one year in Ethiopia and which shall illustrate the diagnostic procedures under field conditions in warm countries as well as under conditions of modern hospitals in moderate climates. Amoebic liver abscess is quickly detected and confirmed by sonography and immunodiagnostic. Contrary to it in the fields there is the puncture by means of a i. v.-needle often not only the sole diagnostic but also the first and sometimes life-saving therapeutic procedure in advanced cases. It allows X-ray in double contrast technique if equipment is available. In suitable cases such approved technique shall be used also in modern clinics disposing of methods like sonography and computerized tomography. Concerning peritoneal tuberculosis our examinations agreed with the opinion of literature that the laparoscopy seems to be the most suitable method for quickly detection and safe discrimination from decompensated portal hypertension in liver cirrhosis. By the way the "cope needle" are mentioned which is distributed in warm countries for searching for peritoneal tuberculosis by performance of a blind peritoneal biopsy. It is easier than laparoscopy but not so efficient. - In this connection 31 cases examined by laparoscopy are presented in a table in order to give an impression on further indications to laparoscopy existing in such areas of warm countries.(ABSTRACT TRUNCATED AT 250 WORDS)