Combined isolation of CD34+ progenitor cells and reduction of B cells from peripheral blood by use of immunomagnetic methods

Valid Presumption of Shiga Toxin-Mediated Damage of Developing Erythrocytes in EHEC-Associated Hemolytic Uremic Syndrome

The global emergence of clinical diseases caused by enterohemorrhagic Escherichia coli (EHEC) is an issue of great concern. EHEC release Shiga toxins (Stxs) as their key virulence factors, and investigations on the cell-damaging mechanisms toward target cells are inevitable for the development of novel mitigation strategies. Stx-mediated hemolytic uremic syndrome (HUS), characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal injury, is the most severe outcome of an EHEC infection. Hemolytic anemia during HUS is defined as the loss of erythrocytes by mechanical disruption when passing through narrowed microvessels. The formation of thrombi in the microvasculature is considered an indirect effect of Stx-mediated injury mainly of the renal microvascular endothelial cells, resulting in obstructions of vessels. In this review, we summarize and discuss recent data providing evidence that HUS-associated hemolytic anemia may arise not only from intravascular rupture of erythrocytes, but also from the extravascular impairment of erythropoiesis, the development of red blood cells in the bone marrow, via direct Stx-mediated damage of maturing erythrocytes, leading to “non-hemolytic” anemia.

Toward complete laser ablation of melanoma contaminant cells in a co-culture outgrowth model via image cytometry

BACKGROUND

Contaminant cancer cells in autologous transplant tissue can cause relapse and the rates are unknown. A method capable of removing all contaminant cells with a high probability detected by cytomic analyses would be useful. Neither 100% cell purging nor techniques for measuring the probability of success have been developed. Here, we report a method for removing 100% of the cells under ideal staining conditions and quantify the probability of success.

METHODS

Laser ablation was combined with previously reported automated microscopy to purge contaminant cells and evaluate 100% ablation in a co-culture model of prestained mouse melanoma cells mixed with mouse NIH-3T3 cells. Melanoma passage efficiency was measured by: (1) micropipetting single cells into microtiter wells and (2) ablating all but one melanoma cell in co-cultures.

RESULTS

(74 +/- 5)% of single melanoma cells pipetted into microtiter plate wells divided at least once. With ablation of all but one contaminant cell in co-cultures, melanoma dominated in (62 +/- 8)% cultures in 21 days. With 100% ablation in six additional experiments, no melanoma outgrowth was observed, giving a >99.1% probability that all contaminant melanoma cells were purged.

CONCLUSIONS

We successfully demonstrated a model for complete ablation within a defined probability using automated high-content image cytometry with ideal staining conditions. The results show that the instrumentation is capable of delivering 100% ablation at a defined probability and establishes the basis for further studies with clinical models wherein pretherapeutic cytomic analyses of unique cellular expression and/or morphological characteristics will be key for contaminant cancer cell identification.

Real-time process/quality control for HPC processing

BACKGROUND

JACIE Standards (FACT Standards in the USA) have been implemented in Europe since 1999. An on-site accreditation inspection took place at our center in January 2004. The purpose of this work was to develop a real-time process/quality control system meeting the JACIE Standards for HPC release.

METHODS

Data from 194 HPC processing procedures for autologous transplantation performed over a 5-year period were analyzed. The results of different processing methods applied at our facility were compared: (1) cryopreservation without washing cells (n=50), (2) washing cells (n=87), (3) cell-density separation (n=12) and (4) positive CD34 selection (n=45).

RESULTS

Four critical control points were set for the validation of HPC processing: (a) number of lost CD34(+) cells during processing, (b) contamination, (c) viability of the cells after thawing and (d) ability to reconstitute hematopoiesis after transplantation. On the basis of statistical analysis, ranges of acceptable values were defined for each critical control point and for each processing method. Those acceptable values were used for cell release and real-time quality control.

DISCUSSION

This study describes a model for the validation of HPC processing and for a real-time process/quality control system for HPC release. Optimization of processing techniques, standardization of methods and comparison between facilities will open the way towards external quality controls and quality improvement.