Flow cytometry (FCM) -Human anagen hair bulbs -Cell cycle kinetics
Recently, we introduced DNA flow cytometry (DNA-FCM) into the study of human hair growth and reported on S-and G2 + M values in plucked anagen hairs [4]. The present investigation was also designed to elucidate cell kinetics in the anagen hair bulb, using DNA-FCM.
Four-millimeter punch biopsy specimens were taken with local anesthesia and without epinephrine, from 21 normal volunteers (11 females, 10 males, aged 18-21 years), 2 cm left of the protuberantia occipitalis, and immediately placed in Minimal Essential Medium (Gibco, Karlsruhe, FRG) containing 20% fetal calf serum. Subsequently, the anagen hairs were meticulously dissected under a stereomicroscope and their bulbs horizontally cut with fine scissors at the widest diameter. Approximately ten anagen bulbs were taken per biopsy for FCM analysis. All participants were obliged to stop all drug intake 4 weeks prior to the day of the investigation, with the exception of oral contraceptives (n = 4) not containing antiandrogens. Biopsy taking was uniformly performed at 2.30 p.m. Male participants were chosen so that they would not have manifest or incipient male pattern alopecia.
ECM measurement of the specimens was performed as previously described [4]. Cell-cycle-stage distribution analysis (i.e., calculation of the percentage of cells in different phases of the cell cycle) was conducted according to the method of Baisch et al.
[2], based on the calculation of a nonlinear back-