Neoplastic Stem Cells: Highly proliferative, self-renewing, and colony-forming stem cells which give rise to NEOPLASMS.Stem Cells: Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.Hematopoietic Stem Cells: Progenitor cells from which all blood cells derive.Stem Cell Transplantation: The transfer of STEM CELLS from one individual to another within the same species (TRANSPLANTATION, HOMOLOGOUS) or between species (XENOTRANSPLANTATION), or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). The source and location of the stem cells determines their potency or pluripotency to differentiate into various cell types.Embryonic Stem Cells: Cells derived from the BLASTOCYST INNER CELL MASS which forms before implantation in the uterine wall. They retain the ability to divide, proliferate and provide progenitor cells that can differentiate into specialized cells.Adult Stem Cells: Cells with high proliferative and self renewal capacities derived from adults.Pluripotent Stem Cells: Cells that can give rise to cells of the three different GERM LAYERS.Hematopoietic Stem Cell Transplantation: Transfer of HEMATOPOIETIC STEM CELLS from BONE MARROW or BLOOD between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). Hematopoietic stem cell transplantation has been used as an alternative to BONE MARROW TRANSPLANTATION in the treatment of a variety of neoplasms.Stem Cell Niche: A particular zone of tissue composed of a specialized microenvironment where stem cells are retained in a undifferentiated, self-renewable state.Neural Stem Cells: Self-renewing cells that generate the main phenotypes of the nervous system in both the embryo and adult. Neural stem cells are precursors to both NEURONS and NEUROGLIA.Induced Pluripotent Stem Cells: Cells from adult organisms that have been reprogrammed into a pluripotential state similar to that of EMBRYONIC STEM CELLS.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Multipotent Stem Cells: Specialized stem cells that are committed to give rise to cells that have a particular function; examples are MYOBLASTS; MYELOID PROGENITOR CELLS; and skin stem cells. (Stem Cells: A Primer [Internet]. Bethesda (MD): National Institutes of Health (US); 2000 May [cited 2002 Apr 5]. Available from: http://www.nih.gov/news/stemcell/primer.htm)Mesenchymal Stem Cell Transplantation: Transfer of MESENCHYMAL STEM CELLS between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS).Stem Cell Factor: A hematopoietic growth factor and the ligand of the cell surface c-kit protein (PROTO-ONCOGENE PROTEINS C-KIT). It is expressed during embryogenesis and is a growth factor for a number of cell types including the MAST CELLS and the MELANOCYTES in addition to the HEMATOPOIETIC STEM CELLS.Mesenchymal Stromal Cells: Bone-marrow-derived, non-hematopoietic cells that support HEMATOPOETIC STEM CELLS. They have also been isolated from other organs and tissues such as UMBILICAL CORD BLOOD, umbilical vein subendothelium, and WHARTON JELLY. These cells are considered to be a source of multipotent stem cells because they include subpopulations of mesenchymal stem cells.
Stem cell theory of aging: The stem cell theory of aging is a new theory which was formulated by several scientists and which postulates that the aging process is the result of the inability of various types of stem cells to continue to replenish the tissues of an organism with functional differentiated cells capable of maintaining that tissue's (or organ's) original function. Damage and error accumulation in genetic material is always a problem for systems regardless of the age.Renal stem cell: Renal stem cells are self-renewing, multipotent stem cells which are able to give rise to all the cell types of the kidney. It is involved in the homeostasis and repair of the kidney, and holds therapeutic potential for treatment of kidney failure.Myeloid: The term myeloid (myelogenous) is an adjective that can refer to a progenitor cell for granulocytes, monocytes, erythrocytes, or platelets. Myeloid can be distinguished from the lymphoid progenitor cells that give rise to B cells and T cells.Human embryonic stem cells clinical trials: ==Human Embryonic Stem Cell Clinical Trials==Pluripotency (biological compounds): The pluripotency of biological compounds describes the ability of certain substances to produce several distinct biological responses. Pluripotent is also described as something that has no fixed developmental potential, as in being able to differentiate into different cell types in the case of pluripotent stem cells.Hematopoietic stem cell transplantationGliogenesis: Gliogenesis is the generation of non-neuronal glia populations derived from multipotent neural stem cells.Stemgent: Stemgent is an American privately funded biotech company focused on providing reagents and technology developed by some of the world's leading stem cell scientists. Founded in 2008, Stemgent has two fully operational facilities in both San Diego, California and Cambridge, Massachusetts.AncestimSB-431542
(1/3999) Differential diagnostic significance of the paucity of HLA-I antigens on metastatic breast carcinoma cells in effusions.
Distinction between benign reactive mesothelial cells and metastatic breast adenocarcinoma cells in effusions from patients with a known prior history of breast cancer is not the easiest task in diagnostic pathology. Here, we report the usefulness of testing the expression of class I HLA antigens (HLA A, B, C) in this respect. Cytospins were prepared from effusions of patients without the history of breast cancer (5 cases) and from effusions of patients with infiltrating ductal carcinoma (11 cases). Three effusions from cancerous patients were not malignant cytologically. The expression of HLA-A, B, C, HLA-DR and beta2-microglobulin as well as the macrophage antigen, CD14, was evaluated by immunocytochemistry. In 10 of 11 effusions the cytologically malignant cells expressed very weak or undetectable HLA-A,B,C as compared to the mesothelial cells and macrophages. The paucity of expression of HLA-A, B, C was detectable in those 3 cases where a definitive cytological diagnosis of malignancy could not be established. In contrast, mesothelial cells and macrophages from all samples were uniformly and strongly positive for both HLA-A, B, C and beta2-microglobulin. We conclude that the paucity of HLA-I antigens provides a marker helpful in distinguishing metastatic breast carcinoma cells from reactive mesothelial cells in effusions. (+info)
(2/3999) Cytokine treatment or accessory cells are required to initiate engraftment of purified primitive human hematopoietic cells transplanted at limiting doses into NOD/SCID mice.
Little is known about the cell types or mechanisms that underlie the engraftment process. Here, we have examined parameters affecting the engraftment of purified human Lin-CD34+CD38- normal and AML cells transplanted at limiting doses into NOD/SCID recipients. Mice transplanted with 500 to 1000 Lin-CD34+CD38- cord blood (CB) or AML cells required the co-transplantation of accessory cells (ACs) or short-term in vivo cytokine treatment for engraftment, whereas transplantation of higher doses (>5000 Lin-CD34+CD38- cells) did not show these requirements suggesting that ACs are effective for both normal and leukemic stem cell engraftment in this model. Mature Lin+CD34- and primitive Lin-CD34+CD38+ cells were capable of acting as ACs even though no repopulating cells are present. Cytokine treatment of NOD/SCID mice could partially replace the requirement for co-transplantation of AC. Furthermore, no difference was seen between the percentage of engrafted mice treated with cytokines for only the first 10 days after transplant compared to those receiving cytokines for the entire time of repopulation. Surprisingly, no engraftment was detected in mice when cytokine treatment was delayed until 10 days posttransplant. Together, these studies suggest that the engraftment process requires pluripotent stem cells plus accessory cells or cytokine treatment which act early after transplantation. The NOD/SCID xenotransplant system provides the means to further clarify the processes underlying human stem cell engraftment. (+info)
(3/3999) Autologous transplantation of chemotherapy-purged PBSC collections from high-risk leukemia patients: a pilot study.
We have recently demonstrated that the combination of the alkylating agent nitrogen mustard (NM) and etoposide (VP-16) is capable of eliminating, ex vivo, leukemic cells contaminating PBSC collections and this is associated with a significant recovery of primitive and committed hematopoietic progenitor cells. Based on these data a pilot study on autologous transplantation of NM/VP-16 purged PBSC for high-risk leukemic patients was recently initiated. Twelve patients (seven females and five males) with a median age of 46 years (range 18-57) have been treated. Two patients had acute myeloblastic leukemia (AML) resistant to conventional induction treatment, four patients had secondary AML in I complete remission (CR), one patient was in II CR after failing a previous autologous BM transplantation, while two additional AML individuals were in I CR achieved after three or more cycles of induction treatment. Two patients with high-risk acute lymphoblastic leukemia (ALL) in I CR and one patient with mantle cell lymphoma and leukemic dissemination were also included. Eight patients showed karyotypic abnormalities associated with a poor clinical outcome. The mobilizing regimens included cytosine arabinoside and mitoxantrone with (n = 6) or without fludarabine (n = 3) followed by subcutaneous administration of G-CSF (5 microg/kg/day until the completion of PBSC collection) and G-CSF alone (n = 3) (15 microg/kg/day). A median of two aphereses (range 1-3) allowed the collection of 7.2 x 10(8) TNC/kg (range 3.4-11.5), 5 x 10(6) CD34+ cells/kg (range 2.1-15.3) and 9.2 x 10(4) CFU-GM/kg (0.3-236). PBSC were treated with a constant dose of 20 microg of VP-16/ml and a median individual-adjusted dose (survival < or = 5% of steady-state BM CFU-GM) of NM of 0.7 microg/ml (range 0.25-1.25). Eleven patients were reinfused after busulfan (16 mg/kg) and Cy (120 mg/kg) conditioning with a median residual dose of 0.3 x 10(4) CFU-GM/kg (0-11.5). The median time to neutrophil engraftment (>0.5 x 10(9)/l) for evaluable patients was 25 days (range 12-59); the median time to platelet transfusion independence (>20 and >50 x 10(9)/l) was 40 days (18-95) and 69 days (29-235), respectively. Hospital discharge occurred at a median of 25 days (18-58) after stem cell reinfusion. Four individuals are alive in CR (n = 3) or with residual nodal disease (n = 1 lymphoma patient) with a follow-up of 32, 26, 3 and 14 months, respectively. Seven patients died due to disease progression or relapse (n = 5) or extrahematological transplant toxicity (n = 2). Our data suggest that pharmacological purging of leukapheresis collections of leukemic patients at high-risk of relapse is feasible and ex vivo treated cells reconstitute autologous hematopoiesis. (+info)
(4/3999) Human immunodeficiency virus-associated Hodgkin's disease derives from post-germinal center B cells.
Human immunodeficiency virus-associated Hodgkin's disease (HIV-HD) displays several peculiarities when compared with HD of the general population. These include overrepresentation of clinically aggressive histologic types and frequent infection of Reed-Sternberg (RS) cells by Epstein-Barr virus (EBV). Recently, we have reported that the histogenesis of HD of the general population may be assessed by monitoring the expression pattern of BCL-6, a transcription factor expressed in germinal center (GC) B cells, and of CD138/syndecan-1 (syn-1), a proteoglycan associated with post-GC, terminal B-cell differentiation. In this study, we have applied these two markers to the study of HIV-HD histogenesis and correlated their expression status to the virologic features of this disease. We have found that RS cells of all histologic categories of HIV-HD consistently display the BCL-6(-)/syn-1(+) phenotype and thus reflect post-GC B cells. Although BCL-6(-)/syn-1(+) RS cells of HIV-HD express CD40, they are not surrounded by CD40 ligand-positive (CD40L+) reactive T lymphocytes, which, in HD of the general population, are thought to regulate the disease phenotype through CD40/CD40L interactions. Conversely, RS cells of virtually all HIV-HD express the EBV-encoded latent membrane protein 1 (LMP1), which, being functionally homologous to CD40, may contribute, at least in part, to the modulation of the HIV-HD phenotype. (+info)
(5/3999) An alternatively spliced form of CD79b gene may account for altered B-cell receptor expression in B-chronic lymphocytic leukemia.
Several functional anomalies of B-chronic lymphocytic leukemia (B-CLL) cells may be explained by abnormalities of the B-cell receptor (BCR), a multimeric complex formed by the sIg homodimer and the noncovalently bound heterodimer Igalpha/Igbeta (CD79a/CD79b). Because the expression of the extracellular Ig-like domain of CD79b has been reported to be absent in the cells of most CLL cases, we have investigated the molecular mechanisms that may account for this defect. Peripheral blood lymphocytes (PBL) from 50 patients and two cell lines (MEC1, MEC2) obtained from the PBL of one of them were studied. MEC1, MEC2, and 75% of CLL cases did not express detectable levels of the extracellular Ig-like domain of CD79b, which was nevertheless present in greater than 80% CD19(+) cells from normal donors. In healthy subjects the expression of CD79b was equally distributed in CD5(+) and CD5(-) B-cell subsets. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of CD79b RNA from all patients and from MEC1 and MEC2 cell lines consistently yielded two fragments of different size (709 bp and 397 bp). The 709-bp band corresponds to CD79b entire transcript; the 397-bp band corresponds to an alternatively spliced form lacking exon 3 that encodes the extracellular Ig-like domain. Both fragments were also visible in normal PBL. The expression of the 397-bp fragment was increased in normal activated B cells, while no difference was seen between CD5(+) and CD5(-) B cells. To obtain a more accurate estimate of the relative proportions of the two spliced forms, a radioactive PCR was performed in 13 normal and 22 B-CLL samples and the results analyzed using a digital imager. The mean value of the CD79b to the CD79b internally deleted ratio was 0.64 +/- 0.20 SD in normal donors and 0.44 +/- 0.27 SD in B-CLL (P =.01). Direct sequencing of 397-bp RT-PCR products and of genomic DNA corresponding to exon 3 from MEC1, MEC2, their parental cells, and five fresh B-CLL samples did not show any causal mutation. Single-strand conformation polymorphism analysis of exon 3 performed in 18 additional B-CLL cases showed a single abnormal shift corresponding to a TGT --> TGC polymorphic change at amino acid 122. We propose a role for the alternative splicing of CD79b gene in causing the reduced expression of BCR on the surface of B-CLL cells. As normal B cells also present this variant, the mechanism of CD79b posttranscriptional regulation might reflect the activation stage of the normal B cell from which B-CLL derives. (+info)
(6/3999) Feasibility of immunotherapy of relapsed leukemia with ex vivo-generated cytotoxic T lymphocytes specific for hematopoietic system-restricted minor histocompatibility antigens.
Allogeneic bone marrow transplantation (BMT) is a common treatment of hematologic malignancies. Recurrence of the underlying malignancy is a major cause of treatment failure. Donor-derived cytotoxic T lymphocytes (CTLs) specific for patients' minor histocompatibility antigens (mHags) play an important role in both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) reactivities. mHags HA-1 and HA-2 induce HLA-A*0201-restricted CTLs in vivo and are exclusively expressed on hematopoietic cells, including leukemic cells and leukemic precursors, but not on fibroblasts, keratinocytes, or liver cells. The chemical nature of the mHags HA-1 and HA-2 is known. We investigated the feasibility of ex vivo generation of mHag HA-1- and HA-2-specific CTLs from unprimed mHag HA-1- and/or HA-2-negative healthy blood donors. HA-1 and HA-2 synthetic peptide-pulsed dendritic cells (DCs) were used as antigen-presenting cells (APC) to stimulate autologous unprimed CD8(+) T cells. The ex vivo-generated HA-1- and HA-2-specific CTLs efficiently lyse leukemic cells derived from acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) patients. No lytic reactivity was detected against nonhematopoietic cells. Sufficient numbers of the CTLs can be obtained for the adoptive immunotherapy purposes. In conclusion, we present a feasible, novel therapy for the treatment for relapsed leukemia after BMT with a low risk of GVHD. (+info)
(7/3999) Evaluation of trisomy 12 by fluorescence in situ hybridization in peripheral blood, bone marrow and lymph nodes of patients with B-cell chronic lymphocytic leukemia.
BACKGROUND AND OBJECTIVE: Trisomy 12 is the most common numerical chromosomal aberration in patients with B-cell chronic lymphocytic leukemia (B-CLL). Fluorescence in situ hybridization (FISH) has improved the detection of this cytogenetic abnormality and has made detection possible in all phases of the cell cycle. The presence of the trisomy 12 positive (+12) cell population has generally been investigated in leukemic cells obtained from the peripheral blood of CLL patients. To ascertain whether trisomy 12 is expressed homogeneously in cells of different hemopoietic tissues, we applied FISH to lymph node, peripheral blood and bone marrow samples obtained simultaneously from 23 untreated B-CLL patients. DESIGN AND METHODS: Twenty-three newly diagnosed patients with B-CLL, 15 in stage B and 8 in stage C, were included in the present study. Peripheral blood smears, bone marrow aspirate smears and lymph node touch imprints were collected from each patient at diagnosis. Cytologic preparations were examined by light microscopy in order to assess the lymphocyte morphology. Immunophenotyping was performed by cytofluorimetric analysis of the peripheral blood, bone marrow and lymph node mononuclear cell suspensions. The diagnosis was supported in all cases by histologic findings in bone marrow biopsy and lymph node biopsy specimens. Fluorescence in situ hybridization was performed on smears of blood and aspirated bone-marrow and lymph node touch imprints obtained by fresh tissue apposition. RESULTS: In 6 of the 23 cases (26%) trisomy 12 was clearly present in all tissues examined. A comparative analysis of the three different hemopoietic tissues was performed. A higher percentage of leukemic CD5+CD23+ cells was detected in lymph nodes than in peripheral blood and bone marrow. A significantly higher proportion of trisomic cells was observed in lymph nodes samples than in peripheral blood or bone marrow smears of trisomy 12 positive CLL patients. INTERPRETATION AND CONCLUSIONS: Several previous reports show that only a proportion of malignant B-CLL cells carry trisomy 12 when analyzed by interphase FISH. The higher proportion of +12 cells in lymph nodes than in peripheral blood or bone marrow of CLL patients with trisomy 12 could reflect different cell distributions in different tissues, or lymph node specific tropism, or proliferative advantage in selected tissue. At present, the role of trisomy 12 in the pathogenesis of lymphoproliferative disorders is unclear. (+info)
(8/3999) Time sequential chemotherapy for primary refractory or relapsed adult acute myeloid leukemia: results of the phase II Gemia protocol.
BACKGROUND AND OBJECTIVE: High-dose cytarabine (HDAra-C), mitoxantrone and etoposide are the mainstay of several active regimens against relapsed or refractory acute myelogenous leukemia (AML). We designed a phase II study to assess the efficacy and side effects of a time sequential application of mitoxantrone plus intermediate-dose Ara-C followed by HDAra-C plus etoposide (GEMIA) in adult patients with refractory or relapsed AML. DESIGN AND METHODS: Patients with refractory or relapsed AML were eligible for GEMIA salvage therapy, which comprised mitoxantrone 12 mg/m2/day on days 1-3, Ara-C 500 mg/m2/day as a 24-hour continuous infusion on days 1-3, followed by HDAra-C 2 g/m2/12-hourly on days 6-8 and etoposide 100 mg/m2/12-hourly on days 6-8. Granulocyte colony-stimulating factor was started on day 14. In patients above the age of 55 the dose of Ara-C in the first sequence (days 1-3) was reduced to 250 mg/m2. RESULTS: Twenty patients were included, of whom 12 achieved complete remission after GEMIA (60%, 95% CI 40-80%), one was refractory and five died early from infection. Two additional patients achieved partial remission after GEMIA and complete remission after consolidation chemotherapy, for a final CR rate of 70% (95% CI 48-88%). Neutrophils recovered at a median of 27 days (range, 22-43) and platelets 46 days (range, 25-59) after the start of treatment. The median duration of remission was 133 days (range, 36-417+) whereas overall survival time lasted for a median of 153 days (range, 13-554+). Treatment-associated toxicity was comprised predominantly of infection, mucositis and diarrhea that reached World Health Organization grades III-V in 40%, 40% and 30% of patients, respectively. Despite the intention to rapidly proceed to a hematopoietic stem cell transplant in patients in remission, only five patients reached the transplant. INTERPRETATION AND CONCLUSIONS: The GEMIA time sequential chemotherapy regimen appears effective in obtaining remissions in refractory and relapsed adult AML. The high toxicity seen, however, suggests that its design is amenable to further improvements, especially in more elderly patients. Since remissions are short-lived, more innovative post-remission strategies are needed. (+info)