Experimental and theoretical studies of the interaction of gas phase nitric acid and water with a self-assembled monolayer.

Nitric acid in air is formed by atmospheric reactions of oxides of nitrogen and is removed primarily through deposition to surfaces, either as the gas or after conversion to particulate nitrate. Many of the surfaces and particles have organic coatings, but relatively little is known about the interaction of nitric acid with organic films. We report here studies of the interaction of gaseous HNO(3) with a self-assembled monolayer (SAM) formed by reacting 7-octenyltrichlorosilane [H(2)C=CH(CH(2))(6)SiCl(3)] with the surface of a germanium infrared-transmitting attenuated total reflectance (ATR) crystal that was coated with a thin layer of silicon oxide (SiO(x)). The SAM was exposed at 298 ± 2 K to dry HNO(3) in a flow of N(2), followed by HNO(3) in humid N(2) at a controlled relative humidity (RH) between 20-90%. For comparison, similar studies were carried out using a similar crystal without the SAM coating. Changes in the surface were followed using Fourier transform infared spectroscopy (FTIR). In the case of the SAM-coated crystal, molecular HNO(3) and smaller amounts of NO(3)(-) ions were observed on the surface upon exposure to dry HNO(3). Addition of water vapor led to less molecular HNO(3) and more H(3)O(+) and NO(3)(-) complexed to water, but surprisingly, molecular HNO(3) was still evident in the spectra up to 70% RH. This suggests that part of the HNO(3) observed was initially trapped in pockets within the SAM and shielded from water vapor. After increasing the RH to 90% and then exposing the film to a flow of dry N(2), molecular nitric acid was regenerated, as expected from recombination of protons and nitrate ions as water evaporated. The nitric acid ultimately evaporated from the film. On the other hand, exposure of the SAM to HNO(3) and H(2)O simultaneously gave only hydronium and nitrate ions. Molecular dynamics simulations of defective SAMs in the presence of HNO(3) and water predict that nitric acid intercalates in defects as a complex with a single water molecule that is protected by alkyl chains from interacting with additional water molecules. These studies are consistent with the recently proposed hydrophobic nature of HNO(3). Under atmospheric conditions, if HNO(3) is formed in organic layers on surfaces in the boundary layer, e.g. through NO(3) or N(2)O(5) reactions, it may exist to a significant extent in its molecular form rather than fully dissociated to nitrate ions.

A double-blind placebo-controlled study with granulocyte-macrophage colony-stimulating factor during chemotherapy for ovarian carcinoma.

In a placebo-controlled double-blind dose-finding trial, 15 patients with ovarian cancer stage III or IV received daily s.c. 1.5, 3, or 6 micrograms/kg recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). At each dose step three patients received recombinant human GM-CSF, and two received placebo. Chemotherapy comprised 6 cycles of carboplatin, 300 mg/m2, and cyclophosphamide, 750 mg/m2, by i.v. bolus on day 1 every 4 weeks. GM-CSF, given on days 6-12 on an outpatient basis, raised the mean leukocyte count on days 7, 10, and 15 and the mean neutrophil count on days 7 and 10 at all dose levels as compared with the control group. Neutrophil counts of less than 0.5 x 10(9)/liter occurred in 20 of 22 cycles in the control group and in 5 of 17 cycles at the 6-micrograms/kg/day GM-CSF dose level (P less than 0.0005). In comparison with the control group, the mean eosinophil count was higher on days 10 and 15 at all GM-CSF doses, as was the mean monocyte count on day 15. The mean platelet count was raised at the 3- and 6-micrograms GM-CSF doses on days 15 and 22. Chemotherapy dose reduction or postponement due to myelotoxicity occurred in 9 of 28 cycles in the placebo groups versus 5 of 44 cycles in the GM-CSF group (not significant). Local skin infiltrates at the GM-CSF injection sites occurred in 8/9 patients, leading to premature removal of two patients from the study. Capillary leakage of 131I-albumin was increased in all patients 5 days after the first chemotherapy course but was not significantly affected by 4 days of GM-CSF treatment. Tumor necrosis factor alpha and C-reactive protein serum levels increased during GM-CSF administration at the 6-micrograms dose level, but interleukin 6 serum levels were not affected. We conclude that a dose of 3 and 6 micrograms/kg/day GM-CSF reduces the severity of neutropenia and thrombocytopenia after carboplatin-cyclophosphamide. This GM-CSF dose does not induce additional capillary leakage.

Recombinant human granulocyte-macrophage colony-stimulating factor reduces hematologic toxicity and widens clinical applicability of high-dose cyclophosphamide treatment in breast cancer and non-Hodgkin's lymphoma.

High-dose administration of anticancer agents is attractive both on theoretic and clinical grounds. Yet, high-dose regimens are usually used as salvage treatments, mainly as a consequence of their considerable hematologic toxicity. One pertinent example is represented by cyclophosphamide, an alkylating agent with a wide spectrum of marked antitumor activity. When used at doses up to 7 g/m2 (190 to 200 mg/kg) this drug does not cause myeloablation, but induces a severe, albeit transient, myelosuppression, which requires platelet transfusions in approximately 50% of treated patients, and is frequently complicated by infectious episodes, occasionally lethal. To accelerate hematopoietic recovery, we continuously infused for 14 consecutive days 5.5 micrograms/kg/d of the glycosylated human recombinant granulocyte-macrophage colony-stimulating factor (rhGM-CSF) into 15 patients with breast cancer and non-Hodgkin's lymphoma treated with 7 g/m2 cyclophosphamide. This schedule was chosen having obtained the fastest hematopoietic recovery among four different options during an initial schedule-finding phase on 12 overall patients. Twenty-one comparable subjects with solid tumors served as controls. We report here that this relatively low, well-tolerated dose of rhGM-CSF reduces from 20 to 14 (median) and from 24 to 14, the number of days required to recover circulating granulocyte counts over 1,000 and 2,500/microL, respectively. The stimulatory effect was associated with a remarkable clinical benefit. In fact, treated patients experienced less infectious complications (7% v 24%) were eligible to receive chemotherapy earlier (median, by day +14 v day +20 for controls), and fewer required prophylactic platelet transfusions (13% v 43%). Our results show that even very high doses of cyclophosphamide can be administered with improved hematologic toxicity, tolerable morbidity, and reduced supportive care requirements. The increase in the therapeutic index made possible by rhGM-CSF infusion prompts the use of high-dose cyclophosphamide, and possibly of other agents with similar myelotoxic activity, early in the clinical course of chemotherapy-sensitive tumors.

In vivo effect of granulocyte-macrophage colony-stimulating factor on the kinetics of human acute myeloid leukemia cells.

Granulocyte-macrophage colony-stimulating factor, (GM-CSF) was given at 8 micrograms/kg daily by continuous i.v. infusion for 72 h to six patients with acute myeloid leukemia (AML) in expansion and one with chronic myeloid leukemia in blastic crisis to determine whether it was possible to augment the proliferative activity of the neoplastic population. The percentage of marrow blasts in S phase (labeling index, LI) was increased in five patients (1.3-, 1.5-, 1.9-, 2.3- and 3.2-fold change). The increase in LI was similar 24 and 48 h after beginning GM-CSF. The RNA Index also increased in patients who showed an increased LI, suggesting that GM-CSF had recruited quiescent neoplastic cells into the cell cycle. Forty eight hours after beginning GM-CSF, chemotherapy was started. The fate of S phase cells, labeled in vivo with bromodeoxyuridine (BrdU) immediately before cytostatic treatment, was monitored. BrdU positive cells were identified by fluorescent antibody for up to 28 days. A preferential killing of BrdU (S phase) cells was observed in 5/7 patients who obtained a complete remission, whereas this was not apparent in the two patients who achieved only a partial remission. Chemotherapy induced a rapid and profound aplasia; its duration, however, was not significantly different from that observed in historical controls. GM-CSF may have a potential role in the treatment of AML, as this study shows that it recruits leukemic cells into the cell cycle without adversely prolonging aplasia after cycle-specific therapy.

Efficacy and tolerability of recombinant human granulocyte-macrophage colony-stimulating factor in patients with chemotherapy-related leukopenia and fever.

30 patients with chemotherapy-related leukopenia (white cells 1.0 x 10(9)/l or lower) and fever (temperature 38.5 degrees C or higher) were treated in a double-blind randomised trial with standard antibiotics and 7 days of intravenously administered recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF, 2.8 micrograms/kg per day) or placebo. GM-CSF administration resulted in a faster percentage increase of peripheral neutrophil count after 2 and 3 days of treatment, except in patients treated with ablative chemotherapy and autologous bone-marrow transplantation. However, GM-CSF did not shorten the period of fever or antibiotic administration. No side-effects were observed; in particular tumour necrosis factor alpha and interleukin-6 did not increase in the 5 GM-CSF patients tested. These data suggest that a subgroup of patients with chemotherapy-related leukopenia and fever may benefit from GM-CSF treatment in view of the observed effects on neutrophil count.

Intervention treatment of established neutropenia with human recombinant granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in patients undergoing cancer chemotherapy.

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was given to 60 patients, in a double-blind, non-prophylactic study of already established chemotherapy-induced leucopenia, for 5 days by continuous intravenous infusion and twice or once daily by subcutaneous injection. Four patients were randomized to rhGM-CSF (3) or placebo (1) at each dose (1.3, 1.7, 5.5, 11, or 22 micrograms of protein/kg). Leucocyte recovery was significantly enhanced compared with controls, in a dose-dependent manner except for 22 micrograms/kg which was ineffective with a worse experience of side effects in some patients. Most adverse events occurred in equal proportions in the treated and placebo cases. Fourteen patients developed infection and were treated with antibiotics in addition to rhGM-CSF. They were joined by a further 18 febrile patients and treated with rhGM-CSF in a subsequent open-label trial. The survival from infection was related to white blood cell (WBC) count: 19 of 32 responded with increased numbers of leucocytes (WBC count above 1.5 x 10(9)/1) after 5 days of GM-CSF. Sixteen of the 19 leucocyte 'responders' recovered from infection, two died from the underlying disease and one from persistent infection. Six of the 13 patients who did not have a leucocyte response died with persistent infection. These data indicate that rhGM-CSF enhances the leucocyte count following chemotherapy and in this way saves critically ill neutropenic patients from fatal infections.

Differentiation markers and accessory function of murine macrophages derived from cultured bone-marrow stem cells.

Murine bone-marrow cells cultured in the presence of colony-stimulating factor from mouse-lung-conditioned medium give rise to macrophages which function as accessory cells in antigen-specific T helper cell induction. Virtually all Ia+ bone-marrow stem cell-derived macrophages express determinants encoded in the I-A subregion. A second set of macrophages bears I-A as well as I-E/C-endoced determinants. The products of the I-A and I-E/C subregion, but not those of the I-J subregion, are involved in T helper cell induction.

Role of human recombinant GM-CSF in the prevention and treatment of leukopenia with special reference to infectious diseases.

Recombinant human GM-CSF has been shown to be effective in reversing severe neutropenic states associated with the underlying disease or caused by cytotoxic drugs, and during engraftment after bone marrow transplantation. Preliminary evidence supports the view that restoration of adequate myelopoiesis results in better control of infection. The use of rhGM-CSF in special infectious diseases to activate cell function is currently being studied. Preliminary in vitro and in vivo data allow high expectations for the usefulness of rhGM-CSF in contributing to the control of these diseases.

Granulocyte Macrophage Colony-Stimulating Factor (GM-CSF) Reduces Pancytopenia After Rescue Therapy in a Patient with Hodgkin's Lymphoma.

After several relapses, a stage IV lymphocyte depletion Hodgkin Lymphoma patient, with a bone marrow progenitor compartment depleted by several courses of chemotherapy, received further combination chemotherapy which caused severe and long-lasting pancytopenia. Because of an objective degree of tumor regression, a second identical course was administered, followed by Granulocyte Macrophage Colony-Stimulating Factor (GM-CSF) in an attempt to accelerate bone marrow recovery. This led to a significantly shorter period of neutropenia and thrombocytopenia with no additional red blood cell and platelet transfusion requirements. Furthermore, the neutropenic phase was not accompanied by septic complications. It is suggested that patients with solid tumors, even with a severely compromised bone marrow after several chemotherapy courses, may benefit from GM-CSF administration after rescue chemotherapy.

Clinical experience with Escherichia coli rHuGM-CSF.

The use of rHuGM-CSF has resulted in patient benefit as shown by reduced infections (MDS and AA), reduced days in intensive care (ABM transplant), better adherence to cancer chemotherapy protocols, and the ability to use full doses of antiviral drugs in AIDS and cytomegalovirus retinitis. The adverse reactions are significant when high doses are used, therefore high doses should be avoided (there is a plateau in the dose-effective biological responses). At recommended doses, GM-CSF is well tolerated and is a valuable adjunctive therapy in the management of patients with conditions of dysmyelopoiesis and myeloid hypoplasia associated with myelotoxic therapy, or after bone marrow transplantation.

The side-effect profile of GM-CSF.

Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic molecule which displays a broad range of haematopoietic activities, has become available for clinical evaluation in various patient groups. It has been shown to be effective in preventing or reversing neutropenia. Adverse effects of GM-CSF, however, are dose related. Appropriate dose, route and schedules for GM-CSF in various clinical settings have recently been defined, the usual range being 5-10 micrograms/kg/day either by 4-6 h intravenous infusion or by subcutaneous injection. At such doses, adverse effects are predominantly mild-to-moderate in nature, occur in 20-30% of patients and usually comprise fever, myalgia, malaise, rash and injection site reaction. Early trials using very high doses of GM-CSF were often associated with marked adverse effects, which in rare cases proved severe (pericarditis and thrombosis). Similarly, a so-called "first-dose reaction", defined as a syndrome of hypoxia and hypotension after the initial but not subsequent doses of GM-CSF, was observed in certain predisposed patients following doses above 10 micrograms/kg/day. Subsequent trials have established that intravenous bolus or short infusions of GM-CSF are more likely to promote adverse effects. Certain patient groups, for example those with myelodysplastic syndrome, acute myeloid leukaemia, inflammatory disease, autoimmune thrombocytopenia or malfunctional immunological responsiveness, require careful clinical monitoring in order to avoid potential complications following the administration of GM-CSF. With the current appropriate administration and doses of GM-CSF, the benefit:risk ratio has been greatly improved.

Ia-bearing bone marrow-cultured macrophages induce antigen-specific helper T cells for antibody synthesis.

In bone marrow cell (BMC) cultures supplemented with colony-stimulating factor (CSF), accessory cells develop that are capable of inducing specific helper T cells. These accessory cells become effective after 4 days in culture and can be found not only in the adherent but also in the nonadherent cell population. On the other hand, very few accessory cells with helper cell-inducing capacity are obtained in BMC cultures without CSF. The active BMC-derived cell type has been shown to carry Ia surface antigen, since pretreatment with anti-Ia serum and complement abolished the capacity of these cells to function like macrophages in helper T cell induction. Moreover, the appearance of functional accessory cells in these cultures coincided with the presence of Ia-bearing cells.

Short-term administration of granulocyte-macrophage colony stimulating factor decreases hematopoietic toxicity of cytostatic drugs.

BACKGROUND: Administration of granulocyte-macrophage colony stimulating factor (GM-CSF) is followed by a rapid increase in the proliferative activity of the hematopoietic precursors. Within 72 hours after its suspension, however, establishment of a negative feedback results in a reduction of the proliferative activity of the hyperplastic marrow to values below the baseline, suggesting refractoriness of hematopoietic progenitors to the action of cell-cycle-specific cytostatic agents. METHODS: The hypothesis that short treatment with GM-CSF before chemotherapy could reduce the hematopoietic toxicity of cytostatics was investigated by administering GM-CSF glycosylate (Sandoz, Basel, Switzerland/Schering-Plough, Kenilworth, NJ) subcutaneously with a 5.5 micrograms/kg protein dosage per day from day-6-day-4 before each course of adjuvant chemotherapy (cyclophosphamide, epirubicin, 5-fluorouracil/cyclophosphamide, methotrexate, 5-fluorouracil alternate) in patients with node-positive breast cancer. Twelve patients were randomized to receive GM-CSF before chemotherapy or only at chemotherapy. The hematologic picture and dose intensity of chemotherapy were compared in the two groups of patients. RESULTS: In the group of patients receiving chemotherapy only, 22% of the cycles had to be postponed because of leukopenia, with a consequent reduction of the dose intensity, whereas in the GM-CSF group, the neutrophil counts remained at significantly (P < 0.001) higher levels, and there were no delays in chemotherapy administration. No substantial systemic toxicity was associated with this brief GM-CSF schedule. Moreover, GM-CSF treatment did not result in delayed depletion of the hematopoietic pool. CONCLUSIONS: Short treatment with GM-CSF can enable the dose intensity of conventional protocols of proven efficacy to be increased.

[In vitro treatment of human bone marrow in the elimination of tumor cells: initial experiences with cytotoxic monoclonal anti-T-cell antibody LAU-A1]. / In-vitro-Behandlung von menschlichem Knochenmark zur Elimination von Tumorzellen: erste Erfahrungen mit dem zytotoxischen monoklonalen Anti-T-Zell-Antikörper LAU-A1.

The authors present evidence that elimination of tumor cells in the bone marrow is essentially possible by in vitro purging with the monoclonal anti-T-cell antibody LAU-A1 and complement; this procedure does not interfere with regeneration capacity of stem cells. These findings have an important bearing with regard to candidates for autologous bone marrow transplantation.

Correction of neutropenia associated with chronic lymphocytic leukaemia following treatment with granulocyte-macrophage colony-stimulating factor.

A patient with chronic lymphocytic leukaemia (CLL) and severe persisting neutropenia due to marrow infiltration of his leukaemia, developed bilateral Legionella pneumophila pneumonia for which he was treated with erythromycin, rifampin and ciprofloxacin. To increase the number of circulating polymorphonuclear neutrophils, the patient was treated with recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) at a dose of 2 micrograms protein/kg bodyweight s.c./12 h. GM-CSF therapy resulted in a sustained rise of the neutrophil count from the fifth day of treatment onwards, without showing an effect on the number of circulating leukemic cells. The patient completely recovered from his pneumonia. It is suggested that the rise of the neutrophil count, due to GM-CSF, contributed to the improvement of the infection of this patient. Our observation illustrates that GM-CSF can be given safely to CLL-patients and that it can be used effectively in CLL patients with severe bacterial infections to restore neutropenia.