Robustness of virus removal by protein A chromatography is independent of media lifetime.

The robustness of virus clearance with respect to protein A media reuse was demonstrated using media with four matrix chemistries: Protein A immobilized ProSep A, Poros A50, Protein A ceramic Hyper DF and MabSelect SuRe, an alkali resistant protein A ligand. Endogenous retrovirus clearance, step yield, impurity clearance and other performance parameters were evaluated periodically in media cycled up to 300 times. Media lifetime was generally limited by either declining step yield or media fouling.

Conditional survival in gastric cancer: a SEER database analysis.

Background: Gastric cancer survival is typically reported in terms of survival from the time of diagnosis. Conditional survival is a more relevant measure of prognosis for patients who have already survived 1 or more years since diagnosis.

Methods: Using the Surveillance, Epidemiology, and End Results (SEER 17) database from the National Cancer Institute, we analyzed data from 20 018 gastric cancer patients diagnosed between 1988 and 1998.

Conditional Survival in Rectal Cancer: A SEER Database Analysis.

Purpose: To provide an analysis of conditional survival (CS) in rectal cancer patients. Cancer survival is typically reported in terms of survival from time of diagnosis. CS can provide improved prognostic information for patients surviving a given period after diagnosis.

Sentinel node staging of primary melanoma by the "10% rule": pathology and clinical outcomes.

Background: Surgical staging of clinically node-negative primary melanoma involves identification and removal of "sentinel" lymph nodes (SLNs). Although some suggest removal of only the "hottest" SLN, the "10% rule" dictates that nodes are removed until the background count is 10% or less of the count of the "hottest" node.

Methods: To determine the utility of the 10% rule, a university database of clinically node-negative melanomas surgically staged by using this rule was examined.

Impact of multiple re-use of anion-exchange chromatography media on virus removal.

We evaluated viral clearance in multiply-cycled anion-exchange media run in flow-through mode. We found that anion-exchange columns do not lose viral clearance capacity after extensive re-use, if they are cleaned with recommended buffers that do not chemically degrade the media. In contrast, anion-exchange (AEX) columns that are not cleaned or are cleaned with buffers that chemically degrade the media lost viral clearance capacity after extended use.