Ovarian cancer stem cells

Because of its semi-solid character in dissemination and growth, advanced ovarian cancer with its hundreds of peritoneal tumor nodules and plaques appears to be an excellent in vivo model for studying the cancer stem cell hypothesis. The most important obstacle, however, is to adequately define and isolate these tumor-initiating cells endowed with the properties of anoikis-resistance and unlimited self-renewal. Until now, no universal single marker or marker constellation has been found to faithfully isolate (ovarian) cancer stem cells. As these multipotent cells are known to possess highly elaborated efflux systems for cytotoxic agents, these pump systems have been exploited to outline putative stem cells as a side-population (SP) via dye exclusion analysis. Furthermore, the cells in question have been isolated via flow cytometry on the basis of cell surface markers thought to be characteristic for stem cells.In the Vienna variant of the ovarian cancer cell line A2780 a proof-of-principle model with both a stable SP and a stable ALDH1A1+ cell population was established. Double staining clearly revealed that both cell fractions were not identical. Of note, A2780V cells were negative for expression of surface markers CD44 and CD117 (c-kit). When cultured on monolayers of healthy human mesothelial cells, green-fluorescence-protein (GFP)-transfected SP of A2780V exhibited spheroid-formation, whereas non-side-population (NSP) developed a spare monolayer growing over the healthy mesothelium. Furthermore, A2780V SP was found to be partially resistant to platinum. However, this resistance could not be explained by over-expression of the "excision repair cross-complementation group 1" (ERCC1) gene, which is essentially involved in the repair of platinated DNA damage. ERCC1 was, nonetheless, over-expressed in A2780V cells grown as spheres under stem cell-selective conditions as compared to adherent monolayers cultured under differentiating conditions. The same was true for the primary ovarian cancer cells B-57.In summary our investigations indicate that even in multi-passaged cancer cell lines hierarchic government of growth and differentiation is conserved and that the key cancer stem cell population may be composed of small overlapping cell fractions defined by various arbitrary markers.

On the decision of outpatient adenoidectomy and adenotonsillectomy in children

OBJECTIVE

Outpatient tonsillectomy and/or adenoidectomy is the procedure of choice in the US, whereas in Europe, the transition from the traditional duration of hospital stay to same day discharge slowly increases. This trial was conducted to find factors, which influence surgery on an outpatient basis and to find possible positive and negative predictive conditions in patients.

METHODS

Most trials, which argue for a same day discharge take the low percentage of postoperative hemorrhage into account. Hemorrhage, apnea and infections are complications and have to be distinguished from sequelae such as poor oral intake (with consecutive i.v. fluid supply), fever and protracted vomiting, that also should be considered as discharge criteria. Complications as well as sequelae were measured in 114 consecutive children, and the patients divided into an adenotonsillectomy group and an adenoidectomy group.

RESULTS

Patients from both groups that underwent surgery because of severe obstructive symptoms had significantly more sequelae than those indicated because of chronic or recurrent infections. They could not have been discharged in an acceptable condition. Due to the fact that most children after adenoidectomy recovered well 8 h postoperatively, they could have been discharged on the same day. Children after adenotonsillectomy had significantly more sequelae. There was a tendency that adenotonsillectomy children with only mild obstructions could have been discharged either 8 or at least 24 h postoperatively. It still remains the surgeon's decision when a child can be discharged safely.