Table 4. Apoptosis in normal and nephropathic cystinotic fibroblasts exposed to serum withdrawal

a The cystine content was decreased in cystinotic cells from 2.3 to 0.5 nmols cystine/106 cells by pretreatment with MEA before incubation in cystine-free and serum-free Ham F12 medium. The cystine content in normal cells was increased from 0.4 to 1.3 nmols cystine/106 cells by treatment with CDME before incubation in serum-free Coon F12 (see Materials and Methods). Cells were stained with CaspACE and analyzed as previously described. P = 0.068 for 008 serum withdrawal versus 05399 serum withdrawal; P = 0.172 for 008 serum withdrawal versus 008 serum withdrawal plus MEA; and P = 0.006 for 05399 serum withdrawal versus 05399 serum withdrawal plus CDME.
Untreated controls2.8 ± 0.43.1 ± 0.5
Serum withdrawal8.7 ± 1.06.1 ± 0.3
Serum withdrawal and MEA7.2 ± 0.4-
Serum withdrawal and CDME-37.3 ± 3.9