Search PubMed⌕ Search

Biomedical subjects

R Mertelsmann

Publications and source records attributed to R Mertelsmann.

At least 217 records · Page 12Linked to original sources
PubMed1990

Inducible production of interleukin-6 by human polymorphonuclear neutrophils: role of granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha.

The recent demonstration of the ability of human polymorphonuclear neutrophils (PMN) to secrete various cytokines in response to the granulocyte activator granulocyte-macrophage colony-stimulating factor (GM-CSF) but not to other cytokines, has led to the identification of PMN as biosynthetically active cells. In this study we have investigated the ability of PMN to secrete interleukin-6 (IL-6), a molecule known to be involved in inflammatory reactions. Using RNA blotting analysis and bioassays, we show that PMN could be induced to synthesize transcripts specific for IL-6, indistinguishable in size from IL-6 mRNA produced by activated human macrophages. Consequently, PMN released IL-6-like activity into their culture supernatants that could be neutralized by monospecific anti-IL-6 antibody. Interleukin-6 secretion by PMN, however, required previous stimulation with GM-CSF or tumor necrosis factor-alpha (TNF-alpha), whereas other cytokines, including interleukin-3 (IL-3), granulocyte-CSF (G-CSF), macrophage-CSF (M-CSF), interferon gamma (IFN-gamma), and lymphotoxin (LT), failed to induce IL-6 mRNA accumulation and protein secretion by PMN. Similar to GM-CSF and TNF-alpha, other compounds, including the inhibitor of protein synthesis cyclohexemide (CHX), endotoxin (Escherichia coli-derived lipopolysaccharide), and phorbol myristate acetate (PMA) (but not the chemoattractant N-formyl-methionyl-leucyl-phenylalanine [FMLP]), induced detectable levels of IL-6 transcripts in PMN.

Blotting, Northern↗
PubMed1990

Pharmacokinetics of recombinant interleukin 2 in humans.

This report summarizes the pharmacokinetics in humans of recombinant interleukin 2 (IL-2) given as an i.v. bolus, i.v. or i.p. infusion, and i.m. or s.c. injection. Immediately after an i.v. bolus the serum IL-2 level equals the dose divided by the plasma volume, in a typical human 650 units/ml for a dose of 10(6) units/m2. The level initially decreases with a half-life of 12.9 min, followed by a slower phase with a half-life of 85 min out to 4 h after the bolus. The median steady state level during an i.v. infusion of 10(6) units/m2 over 6 h is 41 units/ml. A clearance rate of approximately 120 ml/min is obtained from either the i.v. bolus or infusion data and is consistent with the renal filtration being the major route of clearance. Serum levels remain fairly constant for about 8 h after s.c. or i.m. injection but are approximately 2% of the level seen immediately after an i.v. bolus. The area under the time-concentration curve suggests that about 30% of the IL-2 activity is transported from the site of an i.m. injection to the blood. After i.p. infusion IL-2 is only slowly transported to the blood. The median serum IL-2 levels are 430-fold lower than levels in the i.p. fluid and decrease with a median half-life of 6.3 h.

Biological Assay↗
PubMed1990

N-ras gene point mutations in childhood acute lymphocytic leukemia correlate with a poor prognosis.

Ras genes can be altered by point mutations at critical portions of their coding regions to acquire transforming ability in vitro. These point mutations have been detected in a variety of human malignancies. However, their relevance for the clinical and biologic behavior of the subgroups of patients exhibiting these mutations in unclear. We analyzed 100 patients with childhood acute lymphocytic leukemias (ALLs) for point mutations of exons 1 and 2 of all three ras genes (H-ras, K-ras, and N-ras) by polymerase chain reaction and a combination of oligonucleotide hybridization and direct DNA sequencing. A 6% incidence of N-ras gene mutations was detected, all of which occurred at different nucleotides of codons 12 or 13 of N-ras. When correlating presence of ras mutations with the clinical and biologic features and the clinical outcome of these cases, a significantly higher risk for hematologic relapse (P = .01) and a trend toward a lower rate of complete remission (P = .07) was noted. The two groups did not differ in any of the known high-risk factors of ALL. These results suggest that presence of an N-ras mutation in children with ALL may be an independent predictor for worse clinical outcome and therefore may have therapeutic implications; further studies to confirm these findings are required because of the small number of patients with N-ras mutations.

Antigens, CD↗
PubMed1990

Cytokine-stimulation of prostaglandin synthesis from endogenous and exogenous arachidonic acids in polymorphonuclear leukocytes involving activation and new synthesis of cyclooxygenase.

Peripheral blood-derived human polymorphonuclear leukocytes (PMNL) can be induced to synthesize prostaglandin E2 (PGE2) from endogenous and exogenous arachidonic acid (AA) when exposed to agents such as human recombinant (hr) granulocyte-macrophage (GM) colony-stimulating factor (CSF), hr tumor necrosis factor-alpha, hr granulocyte (G)-CSF, lipopolysaccharide and the chemoattractant N-formyl-methionyl-leucyl-phenylalanine. Treatment of PMNL with hr macrophage (M)-CSF and interleukin 3, however, did not result in detectable PGE2 synthesis. Cytokines stimulated PGE2 production during two distinct time intervals, an early peak of PGE2 that was detectable at 20 min and a late one detectable after 4 h. Inhibition of protein synthesis by cycloheximide (CHX) had virtually no effect on the early increase of PGE2 but prevented the late increase. Late addition of CHX to cultures after stimulation with hr GM-CSF at 4 h resulted in decline of PGE2 synthesis from exogenous arachidonic acid. Treatment of PMNL with GM-CSF had direct effects on cyclooxygenase (COx). PMNL depleted from COx by acetyl salicylic acid (ASA) recovered to synthesize PGE2 following exposure to GM-CSF. Recovery from COx inhibition by ASA could be prevented by CHX.

Arachidonic Acid↗
PubMed1990

Effect of granulocyte-macrophage colony-stimulating factor on neutropenia and related morbidity induced by myelotoxic chemotherapy.

A phase Ib/II clinical study was undertaken to assess the efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) to attenuate neutropenia and associated morbidity caused by high-dose anticancer chemotherapy administered in the presence or absence of autologous bone marrow support. We treated 22 patients with various solid tumors and lymphoid neoplasias with a single daily subcutaneous dose of GM-CSF (250 micrograms/m2) 48 h after a second cycle of highly myelotoxic chemotherapy for a period of 10 days and compared intraindividually neutropenia-related clinical and laboratory variables with data obtained from the same patients having previously received a first neutropenia-inducing cycle of identical chemotherapy in the absence of GM-CSF. We show that GM-CSF is active in neutropenic patients by significantly increasing the neutrophil nadir, reducing the time of relevant neutropenia, and reducing the duration of the patient's hospital stay and necessity for parenteral antibiotics. No significant toxicity was encountered with subcutaneous GM-CSF treatment.

Agranulocytosis↗
PubMed1990

Erythropoietin prevents chemotherapy-induced anemia: case report.

A thirty-seven year old male patient with heavily pretreated metastatic testicular carcinoma received escalating doses of recombinant human erythropoietin (EPO) before and throughout chemotherapy. Whereas previous chemotherapy regimens repeatedly caused anemic situations in this patient (hemoglobin (HB) 7.0 g/dl requiring multiple transfusions of red blood cells), EPO given as an i.v. bolus injection at escalating doses of 150 to 300 U/kg body weight (BW) twice/week, starting two weeks prior to the identical myelosuppressive treatment protocol, maintained HB at levels above 8.8 g/dl and thus obviated the need for erythrocyte transfusion. EPO was discontinued after 9 weeks of administration when the patient had achieved a hematocrit (HCT) of 41.1% and a HB of 12.7 g/dl. However, erythropoiesis continued to recover for the next 7 weeks reaching a HCT of 42.4% and a HB of 14.3 g/dl, although the next identical chemotherapy cycle had been given within this period. Along with the rise in HB, ferrokinetics changed significantly as measured by serum ferritin, which was reduced to one third at the end of EPO therapy after only 9 weeks (from 979 ng/ml to 320 ng/ml). No side effects due to EPO administration occurred. These data provide first evidence for efficacy of EPO in chemotherapy-induced anemia and may open new avenues for its clinical application.

Adult↗
PubMed1990

Interferon alfa-2c in chronic myelogenous leukemia (CML): hematologic, cytogenetic and molecular-genetic response of patients with chronic phase CML previously resistant to therapy with interferon gamma.

Alpha- and gamma-interferons have been shown to actively suppress hematopoiesis in patients in the chronic phase of chronic myelogenous leukemia in vitro and in vivo. Since both interferons act through different receptors on their hematopoietic target cells, they are expected to be capable of independently inhibiting abnormal blood cell development in patients with chronic myelogenous leukemia. We have utilized recombinant human interferon alfa-2c to treat 11 patients with Philadelphia chromosome positive chronic myelogenous leukemia in chronic phase, who were resistant to previous interferon gamma therapy. Ten of the patients were evaluable for hematologic, cytogenetic and molecular-genetic response following interferon alfa-2c therapy for 6 to 30 months. In 5 patients, IFN alfa-2c treatment failed due to lack of hematologic response. A complete hematologic or partial hematologic response was achieved in the remaining 5 patients. Three of these experienced cytogenetic improvement with reappearence of 100% diploid hematopoietic cells and disappearence of c-abl/bcr rearrangement in one patient. In two patients interferon alfa-2c did not prevent transformation of the disease into an accelerated state or blast crisis, respectively. We conclude that recombinant human interferon alfa-2c may also control hematopoiesis in interferon-gamma resistant chronic myelogenous leukemia patients, although the long-term response will need to be elucidated in further studies.

Adult↗
PubMed1990

Effect of granulocyte-macrophage colony-stimulating factor on neutropenia and related morbidity induced by myelotoxic chemotherapy.

PURPOSE: A phase Ib/II clinical study was undertaken to assess the efficacy of recombinant human (rh) granulocyte-macrophage colony-stimulating (GM-CSF) factor in attenuating neutropenia and associated morbidity caused by high-dose anticancer chemotherapy administered in the presence or absence of autologous bone marrow support. PATIENTS AND METHODS: Twenty-two patients with various solid tumors and lymphoid neoplasias were treated with a single daily subcutaneous dose of rh GM-CSF (250 micrograms/m2) 48 hours after receiving a second cycle of highly myelotoxic chemotherapy for a period of 10 days. Within-subject comparisons on neutropenia-related clinical and laboratory variables were made with data obtained from the same patients after they received the first neutropenia-inducing cycle of identical chemotherapy in the absence of GM-CSF. RESULTS: GM-CSF was active in neutropenic patients because it significantly increased the neutrophilic nadir, reduced the time of relevant neutropenia, and reduced the duration of a patient's hospital stay and the necessity for parenteral antibiotics. No significant toxicity was encountered with subcutaneous GM-CSF treatment. CONCLUSION: Although GM-CSF was shown to significantly reduce chemotherapy-associated morbidity in patients receiving myelotoxic cancer chemotherapy, additional studies are needed to assess whether the use of GM-CSF in anticancer chemotherapy will allow an increase in the dosage level, leading to improved response rates and survival among cancer patients.

Adolescent↗
PubMed1990

Interleukin-4 regulates mRNA accumulation of macrophage-colony stimulating factor by fibroblasts: synergism with interleukin-1 beta.

We demonstrate that macrophage-colony stimulating factor (M-CSF) is expressed in human fibroblasts at the mRNA and protein level. Following activation with both interleukin (IL)-1 beta and IL-4, fibroblasts synthesized M-CSF transcripts detectable by Northern blot analysis with peak expression occurring at 8 h and 12 h, respectively. Exposure of fibroblasts to both cytokines resulted in M-CSF protein release at 60 h of c. 500 U/ml (for IL-1 beta) and 1000 U/ml (for IL-4), relative to a control preparation of recombinant human M-CSF in a murine bone marrow colony assay. Both interleukins synergized to enhance M-CSF mRNA accumulation and their ability to induce M-CSF transcripts could be abolished by treatment with specific neutralizing antibodies. These observations provide support for the idea that fibroblasts may control monocyte/macrophage development and function, and that IL-1 beta and IL-4 are involved in the regulation of this process.

Blotting, Northern↗
PubMed1990

Erythropoietin for the treatment of anemia of malignancy associated with neoplastic bone marrow infiltration.

This clinical trial was performed to study the effects of intravenously (IV) administered recombinant human (rh) erythropoietin (EPO) at escalating doses (150, 300, and 450 U/kg, administered as an IV bolus injection, twice weekly, for 6, 4, and 4 weeks, respectively) in five patients with low-grade non-Hodgkin's lymphoma (Ig NHL) and bone marrow involvement and one patient with multiple myeloma (MM). All patients were anemic due to underlying disease. None of the patients had a history of bleeding, hemolysis, renal insufficiency, or other disorders causing anemia in addition to bone marrow infiltrating malignancy. Endogenous EPO serum levels were significantly increased in all patients (74 to 202 mU/mL). Five patients (one MM, four small-cell lymphocytic [SCLC] NHL) showed a dramatic increase of hemoglobin (Hb), hematocrit (Hk) and RBC count becoming obvious on the second EPO dose level. Initial ferritin serum values, which were high mostly due to polytransfusion, were significantly reduced in responding patients. Erythropoiesis of one patient with extensive follicular mixed (fm) NHL did not respond to EPO treatment. Platelet (PLT) count increase (greater than 75% above starting levels) during and following EPO therapy was observed in one patient with MM. Adverse events due to EPO therapy have not been recorded. These findings point out a previously unrecognized capacity of EPO given at pharmacologic doses to stimulate erythropoiesis in patients with anemia due to bone marrow infiltration by neoplastic lymphocytes in spite of enhanced endogenous EPO expression.

Aged↗
PubMed1990

Effect of interleukin 3 on cytosine arabinoside-mediated cytotoxicity of leukemic myeloblasts.

The concept of biologic modification of proliferation and differentiation of myeloid leukemia cells has attracted much attention over the past years. One promising strategy involves the recruitment of leukemic cells into the cell cycle by hematopoietic growth factors in combination with cycle-specific cytotoxic drugs. Because cytosine arabinoside (Ara-C), which targets only cells in S-phase of the mitotic cell cycle, is included in most chemotherapeutic regimens for the treatment of acute myelogenous leukemia, we explored the hypothesis that the recruitment of quiescent immature leukemic blasts into the cell cycle by the early acting growth factor interleukin 3 (IL-3) can increase the efficacy of Ara-C for kill of leukemic stem cells. We show that IL-3 increases the fraction of blasts in S-phase, as assessed by DNA histogram analysis with propidium iodide staining, leading to an enhancement of kill of clonogenic blast cells when combined with Ara-C. Expression of the protooncogenes c-myc, c-fms, and c-fos, known to be linked to cellular proliferation and differentiation, was also altered by IL-3 in Ara-C-treated cultures, further substantiating the role that IL-3 plays as an enhancer of the cytotoxicity of Ara-C.

Antigens, CD↗
PubMed1990

Hematopoietic growth factors in bone marrow transplantation.

Preliminary clinical results demonstrate the activity of recombinant human granulocyte (rHuG) and granulocyte/macrophage (rHuGM) colony stimulating factors (CSFs) in enhancing bone marrow engraftment after autologous and allogeneic bone marrow transplantation (BMT). In several analyses of prospective, controlled clinical trials of rHuG- and rHuGM-CSF, reduced morbidity and cost, as well as improved survival have been observed. There is reason to hope that more profound understanding of the in vivo biology of these and other cytokines will lead to further reduction in morbidity and mortality associated with both autologous as well as allogeneic BMT. These advances could significantly broaden the spectrum of diseases amenable to treatment by BMT.

Bone Marrow↗
PubMed1990

Gamma-interferon interrupts growth stimulation in chronic myelogenous leukemia established by endogenous granulocyte colony-stimulating factor.

We have previously shown that maturing neoplastic cells from patients with stable phase chronic myelogenous leukemia (SP CML) constitutively produce granulocyte colony-stimulating factor (G-CSF) and are also receptive for this molecule. G-CSF functions as an endogenous growth factor in SP CML, and thus is responsible for divisions in maturing leukemic cells leading to an expansion of the compartment of mature cells. In the investigations to be reported below, the effects of various hematopoietic inhibitor molecules on the expression of the G-CSF gene by SP CML bone marrow cells enriched for promyelocytes/myelocytes were examined at the mRNA and protein level. We show that exposure of SP CML bone marrow promyelocytes/myelocytes to recombinant human (rh) interferon (IFN)-gamma but not to rh IFN-alpha, rh tumor necrosis factor (TNF)-alpha, and rh lymphotoxin (LT) leads to downregulation of G-CSF expression and interruption of the G-CSF-mediated endogenous growth stimulation. The action of G-CSF takes place at the posttranscriptional level and involves an acceleration of decay of steady-state levels of G-CSF transcripts in the malignant cell population.

Bone Marrow↗
PubMed1990

[In vitro and in vivo effects of recombinant human interleukin-3 on hematopoietic progenitor cells].

As part of a phase I/II clinical trial with recombinant human Interleukin-3 (rhIL-3), bone marrow and peripheral blood cells from patients treated with rhIL-3 were assessed in vitro for effects on the cycling status and frequencies of erythroid, myelomonocytic and multilineage progenitor cells. Treatment with rhIL-3 induced a pronounced increase in S-phase rate of BFU-E, CFU-GEMM and day 14 CFU-GM. Circulating CFU-GEMM and day 14 CFU-GM were increased on day 7 of therapy whereas circulating BFU-E were reduced in the majority of patients. After i.v. bolus injection of IL-3 an acute effect on the peripheral blood count with neutrophilia and, after an initial nadir, monocytosis was observed. IL-6 serum-levels increased in 5 out of 14 patients after IL-3 administration with concomitant side effects in 2 patients in whom IL-6 levels increased above 75 pg/ml. In the majority of the patients a stimulation of peripheral leukocytes and platelets was observed during the 15 day treatment course. In conclusion rhIL-3 induces a multilineage response in vivo by stimulating proliferation of hemopoietic progenitor cells with a resulting elevation in peripheral blood counts.

Bone Marrow↗
PubMed1990

[Proliferation and differentiation in megakaryopoiesis].

Megakaryocytic progenitor cells only complete a limited number of mitotic events; early in megakaryopoiesis, these cells loose their capacity for cell division and acquire the ability for endoreduplication--a phenomenon that is unique to the megakaryocytic lineage. There is growing evidence, that at least two humoral activities affect proliferation of progenitor cells and maturation of its progeny. However, the cytokines that mediate these functionally defined, overlapping activities are not yet precisely known. This review summarizes current understanding of these processes and will discuss the interactions of megakaryocytic cells with the bone marrow microenvironment as well as their role in disorders of hematopoiesis.

Animals↗