Breast cancer mastectomy trends between 2006 and 2010: association with magnetic resonance imaging, immediate breast reconstruction, and hospital volume.

PURPOSE: Analysis of mastectomy rates in breast cancer patients diagnosed between 2006 and 2010 in Germany with focus on impact of breast magnetic resonance imaging (MRI), immediate breast reconstruction (IBR) rates, and hospital volume as possible influencing factors of mastectomy rates. METHODS: Data of a voluntary monitored benchmarking project were used to evaluate mastectomy trends across time in an unselected cohort of breast cancer patients. We used univariate and multivariate logistic regression analysis to identify predictive factors of mastectomy. RESULTS: A total of 142.863 cases were included into the analysis. There was an overall decrease of 5.9% (95% confidence interval 5.1-6.7) in mastectomy trend from 36.5% in 2006 to 30.6% in 2010 (P < 0.0001). Known predictive factors were confirmed. Breast MRI (odds ratio 1.42, 95% confidence interval 1.36-1.47) and small hospitals (<150 cases per year) seem to favor mastectomy. IBR was not associated with mastectomy rates. CONCLUSIONS: Mastectomy rates in comparable health systems differ. Performance of preoperative breast MRI and hospital volume seem to be independent influencing factors for mastectomy rates.

The CD44+ ALDH+ population of human keratinocytes is enriched for epidermal stem cells with long-term repopulating ability.

Like for other somatic tissues, isolation of a pure population of stem cells has been a primary goal in epidermal biology. We isolated discrete populations of freshly obtained human neonatal keratinocytes (HNKs) using previously untested candidate stem cell markers aldehyde dehydrogenase (ALDH) and CD44 as well as the previously studied combination of integrin α6 and CD71. An in vivo transplantation assay combined with limiting dilution analysis was used to quantify enrichment for long-term repopulating cells in the isolated populations. The ALDH(+) CD44(+) population was enriched 12.6-fold for long-term repopulating epidermal stem cells (EpiSCs) and the integrin α6(hi) CD71(lo) population was enriched 5.6-fold, over unfractionated cells. In addition to long-term repopulation, CD44(+) ALDH(+) keratinocytes exhibited other stem cell properties. CD44(+) ALDH(+) keratinocytes had self-renewal ability, demonstrated by increased numbers of cells expressing nuclear Bmi-1, serial transplantation of CD44(+) ALDH(+) cells, and holoclone formation in vitro. CD44(+) ALDH(+) cells were multipotent, producing greater numbers of hair follicle-like structures than CD44(-) ALDH(-) cells. Furthermore, 58% ± 7% of CD44(+) ALDH(+) cells exhibited label-retention. In vitro, CD44(+) ALDH(+) cells showed enhanced colony formation, in both keratinocyte and embryonic stem cell growth media. In summary, the CD44(+) ALDH(+) population exhibits stem cell properties including long-term epidermal regeneration, multipotency, label retention, and holoclone formation. This study shows that it is possible to quantify the relative number of EpiSCs in human keratinocyte populations using long-term repopulation as a functional test of stem cell nature. Future studies will combine isolation strategies as dictated by the results of quantitative transplantation assays, in order to achieve a nearly pure population of EpiSCs.

Spectrochemical analysis of hard metals by a rotating disc technique: effect of impregnation and complexing agents.

A spectrographic method has been developed for the simultaneous determination of the constituents W, Co, Ti, Ta and Nb and contaminants Fe, Ni, Or, Mn, Mg and Ca in hard metals. The samples were dissolved in hydrofluoric acid and nitric acid and the solutions stabilized with citric acid. Graphite discs were waterproofed in order to ensure control of the introduction of solution into the source. For the five types of hard metal samples studied no inter-element effect was observed. Titanium has also been determined by means of a double-beam optical spectrometer.