搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

Megakaryocytopoiesis gives rise to platelets by proliferation and differentiation of lineage-specific progenitors,identified in vitro as Colony Forming Unit-Megakaryocytes (CFU-Mk). The aim of this study was to refine and optimize the in vitro Standard Operating Procedure (SOP) of the CFU-Mk assay for detecting drug-induced thrombocytopenia and to prevalidate a model for predicting the acute exposure levels that cause maximum tolerated decreases in the platelets count,based on the correlation with the maximal plasma concentrations (C max) in vivo. The assay was linear under the SOP conditions,and the in vitro endpoints (percentage of colonies growing) were reproducible within and across laboratories. The protocol performance phase was carried out testing 10 drugs (selected on the base of their recognised or potential in vivo haematotoxicity,according to the literature). Results showed that a relationship can be established between the maximal concentration in plasma (C max) and the in vitro concentrations that inhibited the 10-50-90 percent of colonies growth (ICs). When C max is lower than IC10,it is possible to predict that the chemicals have no direct toxicity effect on CFU-Mk and could not induce thrombocytopenia due to bone marrow damage. When the C max is higher than IC90 and/or IC50,thrombocytopenia can occur due to direct toxicity of chemicals on CFU-Mk progenitors. View Publication

The major goal of researchers and oncologists is to develop promising ground for novel therapeutic strategies to prevent recurrence or relapse of cancer. Recent evidences suggest that a subset of cells called cancer stem cells (CSCs) are present within the tumor mass which possess tumorigenic capacity and may be responsible for propagation,relapse,and metastatic dissemination. These cells have certain stem cell-like properties,e.g. quiescence,selfrenewal,asymmetric division,and multidrug resistance which allow them to drive tumor growth and evade conventional therapies. A number of markers and assays have been designed to isolate and characterize the CSC population from the bulk tumor. The objective now is to selectively target the CSCs in order to eliminate the tumor from root,overcoming the emergence of clones capable of evading traditional therapy. This approach may help in increasing the overall disease-free survival in some cancers. View Publication

Because primary myelofibrosis (PMF) originates at the level of the pluripotent hematopoietic stem cell (HSC),we examined the effects of various therapeutic agents on the in vitro and in vivo behavior of PMF CD34(+) cells. Treatment of PMF CD34(+) cells with chromatin-modifying agents (CMAs) but not hydroxyurea,Janus kinase 2 (JAK2) inhibitors,or low doses of interferon-α led to the generation of greater numbers of CD34(+) chemokine (C-X-C motif) receptor (CXCR)4(+) cells,which were capable of migrating in response to chemokine (C-X-C motif) ligand (CXCL)12 and resulted in a reduction in the proportion of hematopoietic progenitor cells (HPCs) that were JAK2V617F(+). Furthermore,sequential treatment of PMF CD34(+) cells but not normal CD34(+) cells with decitabine (5-aza-2'-deoxycytidine [5azaD]),followed by suberoylanilide hydroxamic acid (SAHA; 5azaD/SAHA),or trichostatin A (5azaD/TSA) resulted in a higher degree of apoptosis. Two to 6 months after the transplantation of CMAs treated JAK2V617F(+) PMF CD34(+) cells into nonobese diabetic/severe combined immunodeficient (SCID)/IL-2Rγ(null) mice,the percentage of JAK2V617F/JAK2(total) in human CD45(+) marrow cells was dramatically reduced. These findings suggest that both PMF HPCs,short-term and long-term SCID repopulating cells (SRCs),are JAK2V617F(+) and that JAK2V617F(+) HPCs and SRCs can be eliminated by sequential treatment with CMAs. Sequential treatment with CMAs,therefore,represents a possible effective means of treating PMF at the level of the malignant SRC. View Publication

Zika virus (ZIKV) is an emerging mosquito-transmitted flavivirus that can cause severe disease,including congenital birth defects during pregnancy(1). To develop candidate therapeutic agents against ZIKV,we isolated a panel of human monoclonal antibodies (mAbs) from subjects with prior ZIKV infection. A subset of mAbs recognized diverse epitopes on the envelope (E) protein and exhibited potently neutralizing activity. One of the most inhibitory mAbs,ZIKV-117,broadly neutralized infection of ZIKV strains corresponding to African,Asian,and American lineages. Epitope mapping studies revealed that ZIKV-117 recognized a unique quaternary epitope on the E protein dimer-dimer interface. We evaluated the therapeutic efficacy of ZIKV-117 in pregnant and non-pregnant mice. mAb treatment markedly reduced tissue pathology,placental and fetal infection,and mortality in mice. Thus,neutralizing human mAbs can protect against maternal-fetal transmission,infection and disease,and reveal important determinants for structure-based rational vaccine design efforts. View Publication

BACKGROUND AND AIMS: Emerging evidence suggests that highly treatment-resistant tumour-initiating cells (TICs) play a central role in the pathogenesis of pancreatic cancer. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered to be a novel anticancer agent; however,recent studies have shown that many pancreatic cancer cells are resistant to apoptosis induction by TRAIL due to TRAIL-activated nuclear factor-kappaB (NF-kappaB) signalling. Several chemopreventive agents are able to inhibit NF-kappaB,and favourable results have been obtained--for example,for the broccoli compound sulforaphane-in preventing metastasis in clinical studies. The aim of the study was to identify TICs in pancreatic carcinoma for analysis of resistance mechanisms and for definition of sensitising agents. METHODS: TICs were defined by expression patterns of a CD44(+)/CD24(-),CD44(+)/CD24(+) or CD44(+)/CD133(+) phenotype and correlation to growth in immunodeficient mice,differentiation grade,clonogenic growth,sphere formation,aldehyde dehydrogenase (ALDH) activity and therapy resistance. RESULTS: Mechanistically,specific binding of transcriptionally active cRel-containing NF-kappaB complexes in TICs was observed. Sulforaphane prevented NF-kappaB binding,downregulated apoptosis inhibitors and induced apoptosis,together with prevention of clonogenicity. Gemcitabine,the chemopreventive agents resveratrol and wogonin,and the death ligand TRAIL were less effective. In a xenograft model,sulforaphane strongly blocked tumour growth and angiogenesis,while combination with TRAIL had an additive effect without obvious cytotoxicity in normal cells. Freshly isolated patient tumour cells expressing markers for TICs could be sensitised by sulforaphane for TRAIL-induced cytotoxicity. CONCLUSION: The data provide new insights into resistance mechanisms of TICs and suggest the combination of sulforaphane with TRAIL as a promising strategy for targeting of pancreatic TICs. View Publication