An ex-vivo human intestinal model to study Entamoeba histolytica pathogenesis.

Amoebiasis (a human intestinal infection affecting 50 million people every year) is caused by the protozoan parasite Entamoeba histolytica. To study the molecular mechanisms underlying human colon invasion by E. histolytica, we have set up an ex vivo human colon model to study the early steps in amoebiasis. Using scanning electron microscopy and histological analyses, we have established that E. histolytica caused the removal of the protective mucus coat during the first two hours of incubation, detached the enterocytes, and then penetrated into the lamina propria by following the crypts of Lieberkühn. Significant cell lysis (determined by the release of lactodehydrogenase) and inflammation (marked by the secretion of pro-inflammatory molecules such as interleukin 1 beta, interferon gamma, interleukin 6, interleukin 8 and tumour necrosis factor) were detected after four hours of incubation. Entamoeba dispar (a closely related non-pathogenic amoeba that also colonizes the human colon) was unable to invade colonic mucosa, lyse cells or induce an inflammatory response. We also examined the behaviour of trophozoites in which genes coding for known virulent factors (such as amoebapores, the Gal/GalNAc lectin and the cysteine protease 5 (CP-A5), which have major roles in cell death, adhesion (to target cells or mucus) and mucus degradation, respectively) were silenced, together with the corresponding tissue responses. Our data revealed that the signalling via the heavy chain Hgl2 or via the light chain Lgl1 of the Gal/GalNAc lectin is not essential to penetrate the human colonic mucosa. In addition, our study demonstrates that E. histolytica silenced for CP-A5 does not penetrate the colonic lamina propria and does not induce the host's pro-inflammatory cytokine secretion.

[Spiegelian hernias. Report of 51 cases]. / Hernies ventrales antérolatérales dites de Spiegel. 51 cas.

We describe 51 cases of Spiegel's hernias, and report a critical review of the relevant literature. The patients presented with an isolated mass in 17 cases, abdominal pain in 17 cases, and a complication in 14 cases (intestinal occlusion in 8, incarceration in 6). The hernia was discovered fortuitously by compute tomography in three cases. The diagnosis was made preoperatively in 31 cases and during surgery in 17 cases. Sonography was contributory in 10 cases and compute tomography in 6 cases. In 47 cases the deep orifice was located at the level of Douglas' arch, in the anterolateral abdomen. The hernial sack remained interstitial in every case, under the aponeurosis of the external oblique. The contents were irreducible or strangulated in 14 cases. Surgery was necessary in all but three cases. The approach was lateral in 43 cases and medial in 5 cases. The indications of laparoscopy in this setting are discussed.