Blood
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We have previously described the isolation of separate populations of CD34+, CD38- stromal and hematopoietic progenitors cells within fetal bone marrow. The CD34+, CD38-, CD50+, HLA-DR+ population contained the majority of primitive hematopoietic progenitor cells, whereas stromal progenitors were contained within the CD34+, CD38-, CD50-, HLA-DR- population. In this study, we compared the frequencies and total numbers of clonogenic CD34+, CD38- stromal and hematopoietic cells as a function of fetal gestational age using single-cell fluorescent-activated cell sorting (FACS). ⋯ In contrast, the total numbers of clonogenic CD34+, CD38-, HLA-DR- stromal progenitor cells remained constant during this period. Although adult bone marrow samples contained stromal progenitor cells at a frequency of approximately 1/7,000 mononuclear cells, clonogenic stromal cells with the CD34+, CD38-, HLA-DR- phenotype could not be isolated by single-cell FACS from these samples. Thus, there are significant differences between the frequencies and biologic characteristics of stromal and hematopoietic stem cells during fetal and postnatal ontogeny.
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Randomized Controlled Trial Clinical Trial
Inhibition of endotoxin-induced activation of the coagulation and fibrinolytic pathways using a recombinant endotoxin-binding protein (rBPI23).
A recombinant endotoxin-neutralizing protein, rBPI23, was shown to partially prevent endotoxin-induced activation of the fibrinolytic and coagulation systems in experimental endotoxemia in humans. In a placebo-controlled, blinded crossover study, eight volunteers were challenged twice with an intravenous bolus injection of endotoxin (40 EU/kg of body weight) and concurrently received either rBPI23 (1 mg/kg) or placebo (human serum albumin, 0.2 mg/kg). rBPI23 treatment significantly lowered the endotoxin-induced fibrinolytic response, ie, reduced the release of tissue-type plasminogen activator, urokinase-type plasminogen activator, plasminogen activator inhibitor antigen, and complex formation of plasmin alpha 2-antiplasmin (P = .0078 for each). ⋯ The endotoxin-induced activation of the procoagulant state as reflected by increase in F1 + 2 fragments and TAT complexes was blunted by rBPI23 infusion (P = .0391 [not significant according to the Hochberg method] and .0078, respectively). These results indicate that rBPI23 is capable of reducing both the activation of the fibrinolytic and the coagulation systems after low-dose endotoxin infusion in humans.
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Letter Case Reports
Transient disappearance of sickle hemoglobin after transfusion.
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Multicenter Study Comparative Study Clinical Trial
Autologous stem cell transplantation after first remission induction treatment in multiple myeloma: a report of the French Registry on autologous transplantation in multiple myeloma.
Eighteen French centers reported 133 autologous stem cell transplantations performed after first remission induction in multiple myeloma. The source of stem cell was marrow (81 cases), blood (51 cases) or marrow plus blood (1 case). The immediate outcome after transplantation was 49 (37%) complete remissions (CRs) (13 maintained, 36 achieved), 61 (46%) partial remissions, 17 failures and 5 toxic deaths. ⋯ Autologous stem cell transplantation is an effective consolidation for patients responding to primary treatment and a salvage therapy for some nonresponding patients. This approach has to be compared to conventional chemotherapy in prospective randomized studies. The critical impact of CR achievement on survival implies new strategies to increase the CR rate.
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T-cell production is largely dependent on the presence of a thymus gland where CD34+ precursors mature into T lymphocytes. Prethymic stages of T-cell development are less defined. Therefore, this study aims to delineate T-progenitor cell potential within the CD34+ Lineage--(Lin-) cell compartment of adult bone marrow (ABM). ⋯ Altogether, our results underscore the fact that T-cell reconstituting potential can be dissociated from HSC activity. Furthermore, we speculate that HSC might develop into the T lineage indirectly, via differentiation into an intermediate oligopotent CD34+ CD45RA+ stage. Finally, T-progenitor cells can be cultured in vitro.