The FLT3 ligand is a direct and potent stimulator of the growth of primitive and committed human CD34+ bone marrow progenitor cells in vitro

The present studies investigated the effects of the recently cloned flt3 ligand (FL) on the in vitro growth and differentiation of primitive and committed subsets of human CD34+ bone marrow (BM) progenitor cells. FL alone was a weak growth stimulator of CD34+ BM cells, but synergistically and directly enhanced colony formation in combination with interleukin (IL) 3, granulocyte colony-stimulating factor (G-CSF), CSF-1, granulocyte macrophage (GM) CSF stem cell factor (SCF), and IL-6. FL and SCF were equally effective in stimulating colony formation in combination with IL-3. However, the tri-factor combination of FL + IL-3 + SCF stimulated 2.3-fold and 2.5-fold more colonies than FL + IL-3 and SCF + IL-3, respectively. These additional recruited progenitors appeared to be predominantly located in a primitive (CD71-) subset of the CD34+ progenitors, as 4.5-fold more colonies were formed by CD34+CD71- cells in response to FL + IL-3 + SCF than to FL + IL-3 or SCF + IL-3. Similar findings were observed in serum-containing and serum-deprived cultures. Whereas FL did not enhance burst-forming unit-erythroid (BFU-E) colony formation of CD34+ BM cells in the presence of serum, a low number of BFU-E colonies were formed in response to FL plus erythropoietin (Epo) under serum-deprived conditions. In addition, FL both in serum-containing and serum-deprived cultures stimulated colony formation of more committed myeloid progenitors in CD34+CD71+ BM cells. Thus, FL potently stimulates the growth of primitive and more committed human BM progenitor cells.     

All-trans-retinoic acid, idarubicin, and IV arsenic trioxide as initial therapy in acute promyelocytic leukemia (APML4)

The treatment of acute promyelocytic leukemia has improved considerably after recognition of the effectiveness of all-trans-retinoic acid (ATRA), anthracycline-based chemotherapy, and arsenic trioxide (ATO). Here we report the use of all 3 agents in combination in an APML4 phase 2 protocol. For induction, ATO was superimposed on an ATRA and idarubicin backbone, with scheduling designed to exploit antileukemic synergy while minimizing cardiotoxicity and the severity of differentiation syndrome. Consolidation comprised 2 cycles of ATRA and ATO without chemotherapy, followed by 2 years of maintenance with ATRA, oral methotrexate, and 6-mercaptopurine. Of 124 evaluable patients, there were 4 (3.2%) early deaths, 118 (95%) hematologic complete remissions, and all 112 patients who commenced consolidation attained molecular complete remission. The 2-year rate for freedom from relapse is 97.5%, failure-free survival 88.1%, and overall survival 93.2%. These outcomes were not influenced by FLT3 mutation status, whereas failure-free survival was correlated with Sanz risk stratification (P[trend] = .03). Compared with our previously reported ATRA/idarubicin-based protocol (APML3), APML4 patients had statistically significantly improved freedom from relapse (P = .006) and failure-free survival (P = .01). In conclusion, the use of ATO in both induction and consolidation achieved excellent outcomes despite a substantial reduction in anthracycline exposure. This trial was registered at the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) as ACTRN12605000070639.     

Tumor necrosis factor (TNF)-alpha directly inhibits human erythropoiesis in vitro: role of p55 and p75 TNF receptors

Two tumor necrosis factor receptors (TNFRs) with molecular weights of 55 kD (TNFR-p55) and 75 kD (TNFR-p75) have recently been identified and cloned. In previous studies, TNFR-p55 has been shown to exclusively mediate bidirectional effects of TNF-alpha on committed bone marrow granulocyte-macrophage progenitor cells, whereas both TNFR-p55 and TNFR- p75 can mediate inhibition of primitive progenitors requiring multiple cytokines to proliferate. We show here that TNF-alpha potently and directly inhibits the in vitro growth of committed erythroid progenitor cells in response to multiple cytokine combinations, and that TNF-alpha- induced inhibition of burst-forming unit-erythroid colony formation is mainly mediated through TNFR-p55, although TNFR-p75-mediated inhibition could be observed on progenitors responsive to erythropoietin alone. Moreover, at low TNF-alpha concentrations (2 ng/mL), TNF-alpha stimulates interleukin-3-dependent in vitro growth of committed granulocyte-macrophage progenitor cells, whereas it potently inhibits erythroid progenitor cell proliferation, showing that one concentration of TNF-alpha can simultaneously and bidirectionally modulate interleukin-3-dependent growth of committed granulocyte-macrophage (stimulation) and erythroid progenitor cells (inhibition).     

Requirement for nuclear factor (NF)-kappa B p65 and NF-interleukin-6 binding elements in the tumor necrosis factor response region of the granulocyte colony-stimulating factor promoter

Granulocyte colony-stimulating factor (G-CSF) is a hematopoietic growth factor produced by mesenchymal and myeloid cells following activation by inflammatory stimuli. It has previously been shown that a region of the G-CSF promoter, (-200 to -165) containing the decanucleotide CK-1 element and two repeated sequences that resemble nuclear factor (NF)- interleukin-6 (IL-6) binding sites, is required for activation of the G- CSF gene by tumor necrosis factor-alpha (TNF-alpha) and IL-1 beta. We now show that the NF-kappa B p65 protein can bind to and activate this TNF response region. There are several unusual features of this p65 interaction with the TNF response region. First, NF-kappa B p65 but not the related NF-kappa B p50 binds to the CK-1 element and a p50/65 hybrid protein that relies on the p50 rel homology domain for DNA binding does not transactivate the TNF response region. Second, p65 transactivation of this region is cell specific and requires not only its own binding site but also the NF-IL6 consensus sites. NF-IL6 also binds to the TNF response region of the G-CSF promoter. Electrophoretic mobility shift studies show that p65 and NF-IL6 can bind cooperatively to the TNF response region. The ability of this region to respond to TNF-alpha or p65 is correlated with the ability to form the p65/NF-IL6 ternary complex.     

AIDS retrovirus antibodies in hemophiliacs treated with factor VIII or factor IX concentrates, cryoprecipitate, or fresh frozen plasma: prevalence, seroconversion rate, and clinical correlations

Antibodies to the AIDS retrovirus, specifically to human T cell lymphotropic virus, type III, and AIDS-associated retrovirus, were detected with increasing prevalence in a population of 190 hemophiliacs from western Pennsylvania between 1981 and 1984: 7.7% in 1981, 20.0% in 1982, 45.5% in 1983, and 62.5% in 1984. The seropositive included approximately three fourths of those receiving factor VIII concentrate, nearly one third of those receiving factor IX concentrate, nearly one fifth of those receiving cryoprecipitate, and none of those receiving fresh frozen plasma. The seroconversion rate, determined on 43 seropositive hemophiliacs from this group who were serially sampled, was 0% in 1977, 4.7% in 1978, 4.9% in 1979, 2.6% in 1980, 10.5% in 1981, 52.9% in 1982, 87.5% in 1983, and 100% in 1984. Of 27 seropositive for three or more years (since 1982 or before), four (15%) have developed AIDS and seven (26%), diffuse lymphadenopathy (ARC); of 16 seropositive for less than three years, none has developed AIDS and three (19%) have developed ARC. The mean time from seroconversion to onset of ARC, 0.8 +/- 0.2 years (SEM), was shorter (P less than .001) than the time to onset of AIDS, 4.1 +/- 0.6 years. These findings confirm the widespread presence of AIDS retrovirus and support the association of these retroviruses with the acquired immunodeficiency syndrome and related conditions.     

Outcome after conservatively managed intracapsular fractures of the femoral neck

Introduction

In 2012, 2.6% of hip-fracture patients in the UK were treated conservatively. There is little data on outcome for these patients. However, one study demonstrated that though 30-day mortality is higher, mortality over the rest of the year is comparable with that in surgical groups. Therefore, we assessed conservatively managed patients in our unit.

Methods

Patients with intracapsular fractures of the femoral neck treated by conservative means between 2010 and 2012 inclusive were identified. Data were collected: American Society of Anaesthesiologists (ASA) grade, Nottingham Hip Fracture Score (NHFS), mobility, mortality (30 days and one year) and pain levels.

Results

Thirty-two patients formed the study cohort. Mean age was 85.6 years. Median ASA grade was 4. Mortality at 30 days and one year was 31.3% and 56.3%, respectively. There was one case of pneumonia and one of infection. Pressure sores or venous thromboembolism were not documented. Three patients underwent surgery once their health improved. In general, mobility was decreased, but 30.8% of patients could mobilise with two aids or a frame. Only two cases had ongoing problems with pain.

Conclusions

Our data are similar to those published previously. Our patients were likely to have higher mortality data due to selection bias. Thirty-day mortality was significantly higher than the national average, but patients surviving 30 days had a prevalence of mortality similar to those managed by surgical means. Despite mobility decreasing from the pre-admission status, a considerable number of patients were free of pain and could mobilise. These data suggest that conservative management of intracapsular fractures of the femoral neck can produce acceptable results.