PubMed · 11209567
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S Sircar. 2000. Misconceptions in physiology.. https://doi.org/10.1152/advances.2000.24.1.62
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OBJECTIVE: To evaluate the fetal middle cerebral artery Doppler waveform for the prediciton of anemia in the RhD-alloimmunized fetus. STUDY DESIGN: Doppler velocimetry of the fetal middle cerebral artery peak systolic velocity was measured in 52 non-hydropic, RhD-alloimmunized fetuses who underwent 103 cordocenteses. Normal values were obtained from 70 normal cases. The peak systolic velocity values were expressed as multiples of the median (MoM) for gestation. Hemoglobin threshold for developing hydrops was developed from 22 RhD-alloimmunized hydropic fetuses and severe anemia was defined as Hb< or =0.60 MoM. The most efficient threshold values for the prediction of severe anemia in groups with no prior transfusion and those with prior transfusion were obtained by constructing ROC curves. RESULTS: The mean gestational age (+/-S.D.) at cordocentesis was 28.0 +/- 4.6 weeks. Severe anemia was noted in 53 (51.5%) occasions. At a threshold middle cerebral artery peak systolic velocity value of > or =1.35 MoM, the sensitivity for severe anemia detection was 100% with a false-positive rate of 18%. In sub-analysis, in patients with one or more prior transfusion a sensitivity of 97% and a false-positive rate of 14% obtained at a threshold of > or =1.45 MoM. In patients with no previous transfusion the sensitivity for severe anemia was 100%, with a false-positive rate of 9.1% at a threshold value of > or =1.35 MoM. CONCLUSION: The middle cerebral artery peak systolic velocity can be used to time both the initial diagnostic procedure and retransfusion.
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We have previously reported the structure of a chromatin remodeling complex (PYR complex) with Ikaros as its DNA binding subunit that is specifically present in adult murine and human hematopoietic cells. We now show that homozygous Ikaros "knockout" (null) mice lack the PYR complex, demonstrating the requirement for Ikaros in the formation of the complex on DNA. Heterozygous Ikaros null mice have about half as much PYR complex, indicating a dosage effect for both Ikaros and PYR complex. We also show that Ikaros null mice have multiple hematopoietic cell defects including anemia and megakaryocytic abnormalities, in addition to previously reported lymphoid and stem cell defects. The null mice also have a delay in murine embryonic to adult beta-globin switching and a delay in human gamma to beta switching, consistent with a previously suggested role for PYR complex in this process. Lastly, cDNA array analyses indicate that several hematopoietic cell-specific genes in all blood lineages are either up- or down-regulated in 14-day embryos from Ikaros null as compared with wild-type mice. These results indicate that Ikaros and PYR complex function together in vivo at many adult hematopoietic cell-specific genes and at intergenic sites, affecting their expression and leading to pleiotropic hematopoietic defects.