Transfusion medicine education for non-transfusion medicine physicians: a structured review.

As transfusion is a commonly identified overused intervention, there is a clear gap between evidence-based and clinical practice. To close this gap, there is not only a need for increased transfusion medicine educational opportunities but for those using structured and proven instructional methods. Kern and colleagues have defined important steps to be considered in curricular design: general needs assessment; targeted needs assessment; goals and objectives; educational strategies; implementation; and evaluation and feedback. We use this framework to examine the current state of transfusion medicine educational initiatives for the non-transfusion medicine physician.

Preinfusion variables predict the predominant unit in the setting of reduced-intensity double cord blood transplantation.

Double cord blood transplantation (DCBT) may overcome the slow hematopoietic recovery and engraftment failure associated with infusion of a single cord blood unit. In DCBT, only one unit typically contributes to long-term hematopoiesis, but little is known about factors affecting cord predominance. As results from a phase I trial suggested that order of infusion may affect cord predominance, we analyzed the effect of preinfusion variables on chimerism patterns of 38 patients enrolled in the initial study and a subsequent phase II trial. All patients were treated with a reduced-intensity conditioning (RIC) regimen of fludarabine, melphalan and thymoglobulin followed by DCBT. By day 100, 66% of patients had hematopoiesis derived from a single cord blood unit. Higher post-thaw total nucleated cell and CD34+ cell dose were associated with cord predominance and in 68% of patients (P=0.03); the predominant cord blood unit was infused first. Only the post-thaw CD34+ cell dose of the predominant unit predicted time to both neutrophil and platelet engraftment. Although based on a small number of patients, our results identify parameters that may affect cord predominance and engraftment in the setting of DCBT following RIC and suggest possible strategies for selecting infusion order for cord blood units.

Serologic and molecular genetic management of a pregnancy complicated by anti-Rh18.

Antibodies, such as anti-Rh18 (Hr/Hr(S)), that react with the common products of RHCE can cause HDN as well as severe hemolytic transfusion reactions. Individuals with anti-Rh18 antibodies can have different RHCE genetic backgrounds; therefore, sera and RBCs from these individuals may cross-react. In these situations, genotyping may be the best method to determine compatibility. We report a 26-year-old pregnant Puerto Rican woman who presented at 31 weeks' gestation with anti-E and anti-Rh18 in her serum. No potential donors were identified among family members or within the American Rare Donor Program; therefore, a unit of the patient's RBCs was collected one week before her planned caesarian section. To improve our ability to supply blood for this patient in the future, molecular testing was performed. The patient was found to be homozygous for an RH haplotype in which a variant RHD*DAR, is linked to a variant RHCE*ceAR. The DAR-ceAR haplotype has been described in Dutch-African populations, but this is the first report of an individual self-identified of Hispanic ethnicity. This case report demonstrates the clinical importance of molecular testing of patients with rare Rh phenotypes.

A nuclear protein tyrosine phosphatase is required for the inactivation of Stat1.

The Stat1 activation-inactivation cycle involves phosphorylation of Stat1 in the cytoplasm, translocation to the nucleus, and then a return of the protein to the cytoplasm in a dephosphorylated state. However, the intracellular site of Stat1 dephosphorylation has not been determined. As receptor signaling declines, the flow of activated Stat1 molecules should be to the site of their dephosphorylation. We found that upon receptor-Janus kinase inactivation, either gradual or abruptly induced by staurosporine treatment, the flow of Stat1 was from cytoplasm to the nucleus and the nucleus was the final compartment in which phosphorylated Stat1 was detected. N-terminal mutants of Stat1, previously shown to remain phosphorylated for a longer time than wild-type Stat1, were able to enter the nucleus and were not inactivated in the presence of staurosporine, directly demonstrating that these mutations affect phosphatase access and/or activity during the normal dephosphorylation of Stat1. In the presence of sodium vanadate, a phosphatase inhibitor, phosphorylated Stat1 accumulated in the nucleus as the total amount of Stat1 in the cytoplasm declined to low levels. We conclude that the nucleus is the site of Stat1 inactivation and that dephosphorylation is required for the rapid nuclear export of Stat1.

The linker domain of Stat1 is required for gamma interferon-driven transcription.

Upon binding of gamma interferon (IFN-gamma) to its receptor, the latent transcription factor Stat1 becomes phosphorylated, dimerizes, and enters the nucleus to activate transcription. In response to IFN-alpha, Stat1 binds to Stat2 in a heterodimer that recruits p48, an IRF family member, to activate transcription. A number of functional domains of the STATs, including a C-terminal transactivation domain, a dimerization domain, and an SH2 domain, are known. However, the highly conserved residues between the DNA binding and SH2 domains (463 to 566), recently christened the linker domain on the basis of crystallographic studies, have remained without a known function. In the present study, we report that KE544-545AA point mutants in Stat1 abolish transcriptional responses to IFN-gamma but not to IFN-alpha. We further show that this mutant Stat1 undergoes normal phosphorylation, nuclear translocation, and DNA binding. Taken together with recent structural evidence, these results suggest that the linker domain acts as a critical contact point during the construction of a Stat1-driven transcriptional complex.

The rapid inactivation of nuclear tyrosine phosphorylated Stat1 depends upon a protein tyrosine phosphatase.

After interferon-gamma (IFN-gamma) treatment of cells the appearance of tyrosine phosphorylated Stat1 in the nucleus was maximal within 20-30 min, remained for 2-2.5 h and activated molecules disappeared by 4 h. In the absence of continued signaling from the receptor (imposed by staurosporine treatment) previously activated Stat1 disappeared completely within 60 min, implying continuous generation and removal of active molecules during extended IFN-gamma treatment. Proteasome inhibitors prolonged the time of activation of Stat1 by prolonging signaling from the receptor but not by blocking removal of already activated Stat1 molecules. By analyzing with 35S labeling the distribution of total Stat1 and activated Stat1, we concluded that the Stat1 molecules promptly cycle into the nucleus as tyrosine phosphorylated molecules and later return quantitatively to the cytoplasm as non-phosphorylated molecules. Therefore, the removal of the activated Stat1 molecules from the nucleus appears not to be proteolytic but must depend on a protein tyrosine phosphatase(s).