In preparation for the EMPRO Flora Study, we carried out a pilot study to investigate different sampling methods in relation to cell yield comparing a brush and a synthetic swab. A fine brush, originally designed for cytology, collected cells effectively but yielded a low count of cells and RBC contamination was high. We hypothesized
that a synthetic flocked swab could be less disruptive and an L-shape possibly better at absorbing MLN8237 cost and releasing cells especially in the case of ectopy, than a brush. We then carried out a comparison study between two synthetic swabs (Copan, MicroRheologics S.R.L., Brescia, Italy) and two brushes (Cellpath® 9 mm ø) in a randomized crossover design over two menstrual cycles with samples taken on day 9 and day 23 (window of 3 days). The endocervical samples were placed in cell medium (PBS, penicillin/streptomycin, l-glutamine, Fetal Calf serum) on ice immediately after collection. Cells were counted in a Neubauer chamber
by one ad the same observer within one hour after trypan-blue staining to identify leukocytes that were alive. The supernatant was tested for blood (free hemoglobin and RBC) and leukocyte esterase with a urine Adriamycin manufacturer dipstick (Servotest®5 + NL, Wesel, Germany). One hundred and twelve samples were collected and the median cell value was 0.31 × 106 (mean of 1.5 × 106). The synthetic swab had a significantly higher yield of cells with an increase of 69% compared to the brush (Table II). Ectopy increased cell yield significantly resulting in a threefold increase and more. There was a borderline
significant increase in yield for day 23 compared to day 9 of the cycle. Blood was significantly more present with the use of a brush compared to the swab (Table III). Another critical factor affecting viability of cells is the freezing process at the sample collection site and during shipment of the samples to the central laboratory.27 A considerable percentage of live cells will not survive the freeze-thaw cycle even when all steps are performed in optimal conditions. Currently, cells are treated with dimethyl sulfoxide (DMSO) before they are frozen with liquid nitrogen. DMSO is known to be toxic to cells at room temperature and lab staff must be careful oxyclozanide not to expose cell samples for any longer than necessary.28 Besides the liquid nitrogen freeze procedures, cell cryopreservation media exist for immediate storage at −80°C for up to three months. Examples of these media are CELLBANKER 1/2 (contains DMSO) or EmbryoMax®.29 This obviously opens possibilities for setting up multi-site or even multi-country clinical trials in the field and batch samples for shipment and analysis; however, it remains to be evaluated how well cells survive when preserved with these new media compared to the traditional DMSO freezing methods.