Table 2.

Numbers of immunogold particles for von Willebrand factor in Mks from the spleen of untreated wild-type and GATA-1low littermates and from mice after 7 days of TPO treatment, as indicated

von Willebrand factor, no. particles
GranulesCytoplasm/DMS
Wild-type mice
Untreated
   Light Mk 103 ± 8 91 ± 8
   Heavy Mk - -
TPO treated
   Light Mk 62 ± 10* 135 ± 4*
   Heavy Mk 33 ± 7* 138 ± 2*
GATA-1low mice
Untreated
   Light Mk 21 ± 2 86 ± 2
   Heavy Mk 8.0 ± 4.5 81 ± 5
TPO treated
   Light Mk 70 ± 10* 142 ± 11*
   Heavy Mk 63 ± 9* 183 ± 6*
  • At least 15 to 20 wild-type and more than 50 GATA-1low Mks were analyzed for the presence of von Willebrand factor-related gold particles. The numbers of gold particles present in 14 μm2 of Mks are presented as mean (± SD) of determinations obtained in 5 randomly selected cells for experimental point. The number of gold granules present in 5 randomly selected 14-μm2 surfaces outside the cells as control are as follows: for untreated wild-type mice, 2.3 ± 0.5; TPO-treated wild-type mice, 1.5 ± 0.5; GATA-1low untreated mice, 1.7 ± 0.4; and GATA-1low TPO-untreated mice, 1.8 ± 0.5.

  • * Data significantly different (P < .05) from those observed in Mks from the corresponding untreated controls