Search PubMed⌕ Search

Biomedical subjects

R Mertelsmann

Publications and source records attributed to R Mertelsmann.

At least 73 records · Page 4Linked to original sources
PubMed1997

Blood progenitor cell (BPC) mobilization studied in multiple myeloma, solid tumor and non-Hodgkin's lymphoma patients after combination chemotherapy and G-CSF.

For blood progenitor cell (BPC) mobilization, standard-dose VIP chemotherapy consisting of etoposide, ifosfamide and cisplatin has previously shown effective tumor reduction in solid tumor patients and sufficient progenitor cell mobilization for autologous blood cell transplantation. Mobilization chemotherapy regimens in multiple myeloma (MM) predominantly consist of melphalan or cyclophosphamide that induce marked cytopenia and considerable variability of progenitor cell collection. We studied whether in MM (n = 13), BPCs were efficiently and reproducibly mobilized with etoposide (500 mg/m2) and ifosfamide (1500 mg/m2), followed by daily s.c. G-CSF (5 micrograms/kg). In parallel, patients with solid tumors or non-Hodgkin's lymphomas (n = 28) treated with etoposide (500 mg/m2), ifosfamide (1500 mg/m2) and cisplatin (150 mg/m2) and identical dosing of G-CSF were analyzed. Before chemotherapy (day 0), on day 7 after chemotherapy and on days of leukapheresis (day 9-14), leukocyte numbers, mononuclear cells (MNCs), CD34+ cells and coexpression of lineage markers were analyzed. Median blood leukocyte numbers were 28,100/microliters (range, 19,600-40,400) on day 10 in myeloma patients and progressively declined over the next 4 days. In contrast, in solid tumor and lymphoma patients leukocyte numbers constantly increased from a median of 12,400/microliters (range, 6000-22,000) to 30,000/microliters (range, 16,300-63,300) between day 10 and day 13 after chemotherapy. Similar to leukocyte counts, median MNC numbers decreased in myeloma patients with successive leukaphereses, but steadily increased in solid tumor and lymphoma patients over the same period. CD34+ cell numbers in the blood peaked between day 9 and 11 (median: 40/microliters) in myeloma patients and then declined. In the solid tumor and lymphoma group, median CD34+ counts in the blood peaked on day 12 after mobilization chemotherapy (median: 100/microliters). The median CD34+ yield per leukapheresis in the myeloma group was 2.2 x 10(6)/kg (range, 1.5-4.7) on day 10, and fell steadily to 0.95 x 10(6)/kg on day 12, whereas in solid tumor/NHL patients median CD34+ cell yields remained between 3.5 and 3.7 x 10(6)/kg from day 10 to day 12 after mobilization chemotherapy (P < 0.001). To obtain sufficient cell numbers for engraftment a median of 2 (range, 1-3) mobilization chemotherapy cycles were needed in MM compared to 1 (range, 1-10) in solid tumor or lymphoma patients, with a median of 5 (range, 2-8) leukaphereses in MM compared to 1 (range, 1-10) (P < 0.05). Taken together, we found that for patients with MM, VP16 and ifosfamide efficiently and predictably mobilizes progenitor cells into the PB with > or = 3 x 10(6)/kg CD34+ cells collected after one to two mobilization chemotherapy cycles.

Adult↗
PubMed1997

Busulfan/cyclophosphamide in volunteer unrelated donor (VUD) BMT: excellent feasibility and low incidence of treatment-related toxicity.

An increasing number of volunteer unrelated donor bone marrow transplantations (VUD-BMT) are performed every year for hematological malignancies due to the availability of a large donor pool. Here we show the results of 36 VUD transplants from our institution using a chemotherapy-only conditioning regimen comprising busulfan 4 x 4 mg/kg and cyclophosphamide 2 x 60 mg/kg. All patients received heparin 200 IU/kg bw continuous i.v. infusion starting the day before conditioning until day +30. Thirty-four of 36 patients (94%) engrafted and no secondary graft failure was observed. The two non-engraftments occurred in patients with CML in blast crisis with extensive myelofibrosis. All 34 engrafted patients (100%) were in complete remission on day +30 as shown by bone marrow biopsy and cytogenetic examinations. No life-threatening treatment-related morbidity or mortality (TRM) were observed, in particular, no severe veno-occlusive disease (VOD) of the liver and no fatal pulmonary complication. Use of G-CSF significantly shortened the time of neutropenia by 5 days. GVHD prophylaxis consisted of CsA/methylprednisolone with or without MTX. Acute GVHD grade II-IV was observed in 18/34 patients (53%) and cGVHD in 12/27 patients (45%), who survived to day +100. In seven patients (four with HLA class I or II mismatch) anti-T-lymphocyte globulin (ATG) was added for acute GVHD prophylaxis. One of seven had aGVHD grade II and none developed grade III to IV GVHD or graft failure. We conclude that Bu/CY is a feasible, save and sufficiently immunosuppressive regimen for VUD transplantation. Severe acute GVHD might be avoided by additional use of ATG in GVHD prophylaxis.

Adult↗
PubMed1997

High-dose chemotherapy with autologous peripheral blood stem cell transplantation for metastatic gastric leiomyosarcoma.

We report a case of metastatic gastrointestinal leiomyosarcoma treated with high-dose combination chemotherapy and autologous peripheral blood stem cell transplantation. After incomplete surgical resection, enteral, peritoneal and hepatic involvement remained. Postoperatively, standard-dose chemotherapy with etoposide, ifosfamide, cisplatin and epirubicine, and high-dose chemotherapy with the same agents (carboplatin replacing cisplatin) was given. Treatment was well tolerated and the patient remains in complete remission at 36+ months. We conclude that high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation may be of use as treatment for inoperable residual disease after resection of the primary lesion in gastrointestinal and other soft tissue sarcomas.

Adult↗
PubMed1997

Adoptive immunotherapy for relapsed multiple myeloma after allogeneic bone marrow transplantation (BMT): evidence for a graft-versus-myeloma effect.

Adoptive immunotherapy with donor-derived buffy coat cells for relapsed hematological malignancies after allogeneic BMT is an established and highly effective treatment. We report a patient who relapsed on day +330 after allogeneic sibling BMT for multiple myeloma with multiple solid subcutaneous tumors consisting of plasma cells. Histology and immunocytology of the bone marrow did not show plasma cell infiltration. After cessation of the immunosuppression consisting of cyclosporine and methylprednisolone, a total of 6.2 x 10(7)/kg recipient body weight CD3+ T cells derived from the donor by leukapheresis were transfused on 4 consecutive days. To enhance the T cell effect six doses of 5 million units alpha interferon were given subcutaneously. Five days later the tumors started to shrink and have completely vanished since day x400 after BMT. The patient developed acute GVHD grade III of the liver and gut which was treated by reinduction of various immunosuppressive drugs. Up to now there is no evidence for relapse of the multiple myeloma, but the patient suffers from extensive chronic GVHD (gut and liver). This is the first report to demonstrate a graft-versus-myeloma effect for relapse with solid tumor manifestation after sibling BMT with donor-derived buffy coat cells as adoptive immunotherapy.

Antibodies, Monoclonal↗
PubMed1997

The human lysozyme gene undergoes stepwise demethylation during phagocyte maturation.

The lysozyme (LZM) gene provides a very useful model for studies of phagocyte maturation, because its protein synthesis is increased during myelopoiesis and thus most abundant in terminally differentiated and activated phagoyctes. LZM gene expression and DNA methylation were examined in various normal and transformed hematopoietic cells. Two shifts toward LZM gene demethylation coincided with upregulation of expression: activation of expression in myeloid precursor cells was associated with significant demethylation at a CpG dinucleotide within an Alu repeat in the 5' flanking region; high-level expression in different types of mature phagocytic cells was associated with complete demethylation at two additional, intragenic CpG sites contained in Alu sequences. The possibility that methylation changes occurring within the 5' region of the human lysozyme gene could be involved in the transcription of this gene is discussed, as well as a possible role for demethylation in the maintenance of distinct maturation stages during phagocyte development.

Cell Differentiation↗
PubMed1997

CD34+ peripheral blood progenitor cell and monocyte derived dendritic cells: a comparative analysis.

Dendritic cells (DC) have been generated in vitro from either CD34+ haemopoietic progenitor cells (HPC) or peripheral blood monocytes (Mo) in the presence of specific cytokine combinations, including granulocyte-macrophage colony-stimulating factor (GM-CSF). Since differences between DC from either source may be important for the clinical use of these antigen-presenting cells (APC), a comparative analysis was performed. HPC were expanded in the presence of interleukin (IL)-3, IL-6 and stem cell factor (SCF) (days 1-7) and subsequently induced by IL-4+ GM-CSF (days 8-26) to differentiate to Langerhans-type cells (pLC). The latter cytokines were similarly used to generate Mo-derived LC (mLC). Maturation of both cell types, pLC and mLC, to interdigitating DC-type cells (iDC) was induced by tumour necrosis factor-alpha (TNF-alpha) or lipopolysaccharide (LPS). Analysis of mLC/pLC and miDC/piDC with respect to morphology, phenotype, antigen uptake and presentation revealed a high similarity of DC from either source. The majority of mLC, however, exhibited a more mature differentiation stage, compared to pLC, evidenced from lower numbers of multilaminar MHC class II compartments and less efficient APC function for extracellular protein antigens. Although macropinocytosis was performed by LC, neither LC nor iDC from either source were able to take up > or = 0.5 microm latex beads. However, phagocytosis of 0.5 microm and 1 microm beads was performed by Mo that could subsequently be induced to become iDC, thus providing the unique opportunity to present phagocytosed material in DC-type fashion. Mo may be the preferential source for clinical use of iDC-type cells since preparation and culture are easier to perform and are less costly while APC function is similar to HPC-derived iDC.

Antigens, CD34↗
PubMed1997

Transforming growth factor-beta 1 delays formation of granulocyte-macrophage colony-forming cells, but spares more primitive progenitors during ex vivo expansion of CD34+ haemopoietic progenitor cells.

Ex vivo culture and expansion of autologous haemopoietic transplants has been developed to improve tumour cell purging and accelerate haemopoietic reconstitution by transplantation of increased progenitor cell numbers. We studied the effect of the negative haemopoietic regulator, transforming growth factor beta-1 (TGF-beta 1) on primitive precursors during ex vivo expansion of CD34+ cells. When added directly to methylcellulose colony-forming assays, TGF-beta 1 potently suppressed the development of granulocyte-macrophage colonies from CD34+ enriched peripheral blood progenitor cells (80-90% inhibition). In contrast, expansion of total nucleated cells and granulocyte-macrophage colony-forming cells (GM-CFC) from CD34+ progenitors in liquid culture in the presence of stem cell factor (SCF), interleukin (IL)-1 beta, IL-3, IL-6 and erythropoietin (EPO) was inhibited to 32-65% of control culture levels within 14 d when TGF-beta 1 was added, and still produced an average 3.3-fold absolute amplification of GM-CFC. The inhibitory effect of TGF-beta 1 on GM-CFC generation was reversed when it was washed out on day 6 of ex vivo expansion cultures, and total numbers of GM-CFC generated from expansion cultures then reached levels of untreated controls by day 16. Long-term bone marrow culture-initiating cell (LTCIC) numbers were preserved, at least at input levels, over a culture period of 14 d both in control and TGF-beta-1-treated expansion cultures. These findings suggest that TGF-beta 1, a cytokine which induces apoptosis or terminal differentiation in a number of malignant cell types, may be added to ex vivo expansion cultures without loss of primitive cells from autologous haemopoietic transplants.

Apoptosis↗
PubMed1997

Cytokine and chemokine production by CD34+ haemopoietic progenitor cells: detection in single cells.

In vitro expansion of haemopoietic progenitor cells (HPC), lineage-specific differentiation, and gene transfer are all based on in vitro culture systems using haemopoietic growth factors (HGF). A close control of the actual culture conditions, however, is difficult due to secondary mediators secreted by the heterogenous population of mature and immature cells in culture. Although monocytes and granulocytes have already been identified as active producers, this study specifically addressed the role of CD34+ progenitor cells in this respect. Using an immunostaining method that enables simultaneous detection of cytokines and phenotype, 56 +/- 6% CD34+ peripheral blood progenitor cells (PBPC) were found to contain cytoplasmic IL-8 after stimulation with phorbol myristate acetate + ionomycin for 90 min. 19 +/- 40%, stained positive after TNF-alpha induction (20 h), and 7 +/- 1% expressed IL-8 in the presence of culture medium alone. Intra-cytoplasmic TNF-alpha and IL-1beta were detected at lower frequency, and < 1% of CD34+ cells expressed IL-1ra or IL-6, whereas IL-1alpha, IL-10 and G-CSF were not detected. Thus, CD34+ HPC are able to synthesize chemo- and cytokines that may operate in an auto- or paracrine manner to modulate in vivo as well as in vitro growth and differentation of haemopoietic cells.

Antigens, CD34↗
PubMed1997

Supportive care in hematologic malignancies, including hematopoietic growth factors, transfusions, and infectious complications.

This review focuses on some of the recent developments in the field of supportive care in hematologic malignancies. The increasingly important role of hematopoietic growth factors in modern treatment modalities for hematologic disorders is clear. Newer developments in transfusional therapy and in the management of infectious complications are also discussed.

Blood Transfusion↗
PubMed1997

Processing of tumor tissues for vaccination with autologous tumor cells.

Vaccination with gene-transfected tumor cells has recently been proposed as a new strategy in the immunotherapy of cancer. Since autologous tumor cells provide an optimal antigen profile, the possibility of generating single cell suspensions from renal cell carcinoma (RCC), malignant melanoma (MM), colon carcinoma (CC), and non-small-cell lung cancer (NSCLC) biopsies was investigated. One hundred and seventy-four tumor biopsies were processed by mechanic and enzymatic dissociation, yielding 1-2 x 10(6) cells/g tumor (median), irrespective of tumor type. Primary tumor cell cultures (PTCC) of > or = 10(7) cells were established from 29 of 86 (34%) RCC, 14 of 38 (37%) MM, 11 of 23 (48%) NSCLC and 4 of 27 (15%) CC specimens. The amount of non-tumor cells, as assessed by morphology and immunocytology, was generally low (< 30%) in RCC (35 of 41) and MM (11 of 17), while it exceeded 60% in 8 of 11 PTCC from NSCLC and 3 of 11 CC. A high tumor cell yield was obtained in biopsies with a high degree of vascularization and in the virtual absence of necrosis. Thus, PTCC > or = 10(7) cells were obtained in 73% of MM with a high degree of vascularization and in 22% of MM with a low degree of vascularization (p < 0.007). Long-term tumor cell cultures exceeding 20 passages were established in 24 of 86 (18%) RCC, 7 of 38 (18%) MM and 3 of 27 (11%) CC, while successful implantation in nude mice was achieved in 8 of 20 RCC and 5 of 10 MM. Thus, under the conditions described, > or = 10(7) primary tumor cells of high purity could be generated from about one third of RCC and MM biopsies, while the success rate increased to > 50 and > 70%, respectively, in samples with a high degree of vascularization generated by an optimized biopsy technique excluding necrotic parts.

Animals↗
PubMed1997

Successful treatment of disseminated central nervous aspergillosis in a patient with acute myeloblastic leukemia.

Invasive opportunistic mycoses are common complications in patients suffering from hematological disorders. Brain abscesses in the immunocompromised host are known to be most frequently caused by fungi of the Aspergillus species and are often associated with concomitant pulmonary disease. As the penetration of the currently available antifungal agents into the brain tissue is limited, only very few patients have been described to survive this life-threatening condition. We report the case of a 62 year old female patient who presented with multiple aspergillus brain abscesses during prolonged neutropenia following induction chemotherapy for acute myeloblastic leukemia and was successfully treated with high dose (8 mg/kg/day) liposomal amphotericin B.

Amphotericin B↗
PubMed1997

Cytosine methylation changes during normal hematopoiesis and in acute myeloid leukemia.

The possible role of DNA methylation changes during several commitment steps of immature myeloid precursor cells toward functional, terminally differentiated phagocyte cells has previously been examined in the human myeloperoxidase (MPO) and macrophage colony-stimulating factor/c-fms genes using normal and transformed myeloid precursor cells. The human lysozyme (LZM) gene also provides a very useful model, because its protein synthesis is continuously increased during myelopoiesis and thus most abundant in mature phagocytes. Several shifts toward LZM gene demethylation coincide with upregulation of expression: activation of expression in myeloid precursor cells and in primary cells of acute myeloid leukemia (AML) was associated with demethylation at a CpG dinucleotide within the 5' flanking region; high-level expression in different types of normal mature phagocytic cells was associated with complete demethylation at two additional, intragenic CpG sites. Methylation changes occurring within the lysozyme gene could reflect transcriptional control of gene expression or maintenance of distinct maturation stages during phagocyte development. They correlate with maturational arrest and lysozyme gene expression in acute myeloid leukemias and may thus provide a genetic marker for the blocked differentiation of these neoplastic cells. Similar observations have been made for the MPO and c-fms genes.

Cytosine↗
PubMed1996

Systemic hematological effects of granulocyte colony-stimulating factor produced by irradiated gene-transfected fibroblasts.

Although long-term expression of therapeutic molecules is necessary for the treatment of permanent deficiencies, short-term expression of therapeutic molecules inducing local or systemic effects is preferable in clinical situations where temporary substitution is the goal. One such clinical setting is the administration of hematopoietic growth factors in cancer chemotherapy-induced myelosuppression. Several plasmid vectors containing the human granulocyte colony-stimulating factor (G-CSF) gene under transcriptional control of different regulatory elements were constructed. In vitro production of G-CSF by nonvirally transfected murine fibroblast clones initially increased after lethal irradiation and was detectable for at least 12 days. We also demonstrate that a single injection of irradiated G-CSF-secreting fibroblasts leads to accelerated hematopoietic recovery and mobilization of committed peripheral blood progenitor cells equivalent to that achieved by twice daily s.c. administration of high doses of recombinant human G-CSF. Using dicistronic vectors, high levels of G-CSF secretion were also obtained in human fibroblasts.

Animals↗
PubMed1996

IL-10 induces DNA binding activity of three STAT proteins (Stat1, Stat3, and Stat5) and their distinct combinatorial assembly in the promoters of selected genes.

Interaction of IL-10 with its receptor leads to the activation of STAT transcription factors. Herein we report the IL-10 dependent simultaneous activation of three STAT transcription factors: Stat1, Stat3, and Stat5. Upon IL-10 treatment multiple Stat proteins become simultaneously activated, and bind to different promoters with equal kinetics but form distinct homo- and heterodimeric transcriptionally active complexes depending on the STAT-consensus elements of a selected gene promoter. Upon IL-10 treatment Stat1, 3, and 5 bind to the GRR of the FcgammaRI gene, activated Stat1 and 3 bind to the SIE sequence of the c-fos promoter and transcriptionally active Stat5 assembles at the PRL-STAT consensus sequence of the beta-casein gene. Thus, functionally relevant STAT dimerization is influenced by the activated cytokine receptor as well as the specific STAT consensus sequence present in a specific gene promoter.

B-Lymphocytes↗
PubMed1996

Systematic evaluation of chimeric marker genes on dicistronic transcription units for regulated expression of transgenes in vitro and in vivo.

Plasmid expression vectors combining human cytokine cDNAs and selectable marker genes on dicistronic transcription units were functionally characterized in vitro and in vivo. The internal ribosome entry sequence (IRES) of encephalomyocarditis virus mediated cap-independent translation of the downstream cistron. After cationic lipofection of cells with a dicistronic construct containing the Neor gene downstream of a human interleukin-2 (IL-2) cDNA, all G418-resistant clones secreted high amounts of IL-2. Reversal of the order of the cDNAs was associated with less efficient transgene expression and represented no advantage in comparison to separate expression cassettes. To combine direct in vitro selection of expression with in vivo elimination of cytokine-secreting cells, an improved chimeric cDNA of the Neor and herpes simplex virus (HSV) thymidine kinase (TK) genes was constructed and shown to confer sensitivity to ganciclovir concentrations that can be achieved in human patients. This chimeric marker was coupled on dicistronic constructs with a granulocyte colony-stimulating factor (G-CSF) cDNA as a molecule with easily detectable bioactivity in vivo. Subcutaneous implantation of pCMV.GCSF.ires TK/NEO-transfected CMS-5 cells into syngeneic BALB/c mice resulted in excessive leukocytosis and progressively growing tumors. Treatment with ganciclovir led to normalization of leukocyte counts in all animals, whereas complete regression of tumors was observed in only 3/5 mice. Hypermethylation of the transfected promoter was demonstrated in both ganciclovir-resistant tumors. Thus, transcription units combining selectable markers and genes of interest allow selection of high producer cells in vitro and efficient elimination of transgene-expressing cells in vivo. However, cells that hypermethylate transfected genes to terminate gene expression in vivo may escape conditional ablation.

Animals↗