A comparison of manual counting of rabbit reticulocytes with ADVIA 2120i analyzer counting

We compared manual counting of reticulocytes in rabbits with automatic counting using an ADVIA 2120i analyzer. Reproducibility and the influence of different anticoagulants (EDTA and Li-heparin) were also examined. Blood samples of 331 rabbits (method comparison, n = 289; reproducibility, n = 33; comparison of anticoagulants, n = 9) were tested. The reticulocyte numbers of each specimen were manually determined twice for method comparison. Passing–Bablok regressions, Bland–Altman plots, and the coefficient of variation (CV) were used to evaluate statistical significance. Good correlation (rs = 0.81) was observed between manual reticulocyte counting (groups 1–4) and the ADVIA 2120i. Quantification with the ADVIA 2120i was reproducible for relative reticulocyte numbers (EDTA, CV = 4.24%; Li-heparin, CV = 3.63%) and absolute reticulocyte numbers (EDTA, CV = 5.64%; Li-heparin, CV = 3.81%). The absolute and relative reticulocyte numbers were significantly higher in Li-heparin samples than in EDTA samples (absolute, p = 0.009; relative, p = 0.016). The ADVIA 2120i is suitable for counting reticulocytes in rabbit blood samples, but reticulocyte numbers are higher by manual counting than by ADVIA 2120i counting. Therefore, microscopic confirmation of quantifications is recommended when high numbers of reticulocytes are observed. The anticoagulant of choice is EDTA.

From Rabbit Reticulocytes to Clam Oocytes: In Search of the System That Targets Mitotic Cyclins for Degradation

By the late 1980s, the basic biochemistry of ubiquitin-mediated protein degradation had already been elucidated by studies that used reticulocyte lysates. However, the scope and biological functions of this system remained largely obscure. Therefore, I became interested at that time in the mechanisms by which mitotic cyclins are degraded in exit from mitosis. Using a cell-free system from clam oocytes that faithfully reproduced cell cycle stage–specific degradation of cyclins, we identified in 1995 a large ubiquitin ligase complex that targets mitotic cyclins for degradation. Subsequent studies in many laboratories showed that this ubiquitin ligase, now called the anaphase-promoting complex/cyclosome, has centrally important roles in many aspects of cell cycle control.