1. Measuring apoptosis in human spermatozoa: a biological assay for semen quality? 
G.Jurjen E Oosterhuis, M.D., Andre B Mulder, M.D., Ph.D., Ellen Kalsbeek-Batenburg, B.Sc., Cornelis B Lambalk, M.D., Ph.D., Joop Schoemaker, M.D., Ph.D., Istvan Vermes, M.D., Ph.D. 
Fertility and Sterility 
Volume 74, Issue 2, Pages (August 2000)
DOI: /S (00)

2. Figure 1
(A) Forward-angle light scatter/side-angle light scatter dot plot. (B) Dot plot of double staining with fluorescein isothyocyanate–labeled Annexin V and propridium iodide (PI). The lower left quadrant contains viable, nonapoptotic cells, which exclude PI and are negative for fluorescein isothyocyanate–labeled Annexin V. The lower right quadrant shows apoptotic cells, which exclude PI but bind Annexin V. The upper right quadrant represents secondary necrotic cells, which bind Annexin V as well as PI.
Oosterhuis. Apoptosis in spermatozoa. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )

3. Figure 2
Frequency distribution histograms of spermatozoa stained with fluorescein isothyocyanate–labeled dUTP without using TdT (A; negative control); with DNase, which digests DNA (B; positive control); and with the use of TdT (C). The horizontal line indicates apoptotic spermatozoa that are positive for fluorescein isothyocyanate–labeled dUTP.
Oosterhuis. Apoptosis in spermatozoa. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )

4. Figure 3
Inverse correlation between TUNEL-positive spermatozoa and sperm count (r = −0.629; P<.0001).
Oosterhuis. Apoptosis in spermatozoa. Fertil Steril 2000.
Fertility and Sterility  , DOI: ( /S (00) )