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Biomedical subjects

G Gastl

Publications and source records attributed to G Gastl.

At least 91 records · Page 5Linked to original sources
PubMed1989

Combination effects of human recombinant interferon (alpha-2-arg, gamma) and cytotoxic agents on colony formation of human melanoma and hypernephroma cell lines.

Malignant melanoma and hypernephroma show marginal response to chemotherapeutics and interferons when used as single agents. Using a modified soft agar clonogenic assay we investigated the antiproliferative effects of combinations of vinblastine, bleomycin, adriamycin, interferon alpha and gamma. On the hypernephroma cell line combinations of bleomycin and adriamycin with interferon gamma as well as combinations of both interferon types resulted in a synergistic antiproliferative effect. On the melanoma cell line combinations of bleomycin and adriamycin with interferon alpha and combinations of vinblastine with interferon gamma acted in a synergistic manner. All other combinations tested were only additive. Thus far, we could not find any antagonistic effect of interferons and chemotherapeutics.

Antineoplastic Agents↗
PubMed1989

[The intraperitoneal installation of gamma interferon for the treatment of refractory ovarian carcinoma].

Patients with refractory ovarian cancer were treated intra-peritoneally with interferon-gamma. The maximum tolerated dose was achieved at 2 mg/m2. The substance was administered 3 times per week every second week. Interferon-gamma treatment activated locally the macrophages and induced a rise in neopterin urine, serum, and ascites levels. The tumor marker CA-125 showed marked fluctuations of more than 100% during interferon treatment and this was not correlated with neopterin. A flu-like syndrome and especially fatigue were the dose limiting side effects. Two of 3 evaluable patients died on tumor progression whereas one is now 18 months clinically free of disease.

Aged↗
PubMed1989

Acute effects of single doses of recombinant interferon-gamma on blood cell counts and lymphocyte subsets in patients with advanced renal cell cancer.

The object of this study was to investigate the effects of different single doses of recombinant interferon-gamma (rIFN-gamma) on white blood cell counts, differential blood counts, and the relative composition of T-cell subsets in the peripheral blood of cancer patients. Sixteen patients suffering from metastasizing renal cell carcinoma received 10, 100, or 500 micrograms of rIFN-gamma three times at weekly intervals. After a therapy-free interval of 2 weeks, the next dose level was applied. The order of dose levels was assigned randomly to each patient. White blood cells, differential blood counts, and the number of Leu1, Leu3, Leu2a, Leu7, and HLA DR+ cells were measured immediately before and at 4, 24, 48, 72, 96, and 168 h after the administration of single doses of rIFN-gamma. Results indicated that white blood cells were transiently removed from the blood circulation after administration of IFN-gamma. Monocytes, HLA DR+ cells, and Leu7+ cells were reduced to below 50% of pretreatment values 4 h after application of the cytokine. CD8+ cells and granulocyte counts declined to approximately 70% of pretreatment values 24 h after IFN therapy. The preferential reduction of CD8+ lymphocytes resulted in a temporary increase of the T4/T8 ratio in these patients.

Adult↗
PubMed1989

Successful treatment of metastatic renal cell carcinoma with a biologically active dose of recombinant interferon-gamma.

We tested the clinical efficacy of a biologically active dose (BAD) of interferon (IFN)-gamma for treatment of progressive renal cell carcinoma (RCC). Twenty-two RCC patients with disease progression subsequent to nephrectomy were entered on a phase II clinical trial. During an initial dose-finding phase, biochemical responses to repeated once-weekly subcutaneous injections of 10, 100, or 500 micrograms of recombinant IFN-gamma were tested in 16 patients. Results indicated that 100 micrograms IFN-gamma applied once weekly was biologically active with induction of serum beta 2-microglobulin and neopterin. Such a dose induced a nearly maximum response of both markers lasting more than 4 days. This dose was also associated with minimal side effects. A dose of 100 micrograms IFN-gamma given once weekly was, therefore, subsequently given weekly for long-term treatment. During a median time of therapy of 10 months (range, 2 to 32 months) two complete (CR; 20+, 20+ months) and four partial tumor responses (PR; 6+, 7+, 8+, 24+ months) were seen (30% CR plus PR; 95% confidence limits, 12% to 54%) among 20 patients evaluable for response. Patients with refractory disease had significantly lower IFN-gamma-induced increments of serum beta 2-microglobulin than those who achieved clinical remission or stable disease.

Adult↗
PubMed1989

Comparison of clinical efficacy and toxicity of conventional and optimum biological response modifying doses of interferon alpha-2C in the treatment of hairy cell leukemia: a retrospective analysis of 39 patients.

Hairy cell leukemia (HCL) has been shown to be extraordinarily sensitive to treatment with alpha-interferon (IFN). In order to define clinically effective IFN doses associated with minimal toxicity, the therapeutic efficacy and side effects of recombinant IFN-alpha-2C treatment of HCL were compared for two different dose regimens: 18 patients (group A) received conventional doses of recombinant IFN-alpha-2C (2 x 10(6)U/m2) for a median time of 35 weeks (range 26-52 weeks), and 21 patients (group B) received optimum biological response-modifying doses of IFN-alpha-2C (0.2-0.6 x 10(6)U/m2) for a median time of 31 weeks (range 12-52 weeks). Interferon was administered daily subcutaneously for 3 months and then every second or third day. Induction of neopterin excretion was chosen as the marker for definition of biological response. The smallest IFN dose causing maximum in vivo induction of biosynthesis of the GTP-degradation product neopterin was deemed "biologically optimal." Both dose regimens were effective, but the low-dose regimen was almost free of toxicity. Thus, in HCL patients alpha-IFN related toxicity can be separated from its antineoplastic activity. Low doses of alpha-IFN should be considered for treatment of HCL patients who develop toxic side effects and for primary treatment of HCL patients with severe cytopenia.

Adult↗
PubMed1988

abl oncogene expression in non-Hodgkin lymphomas: correlation to histological differentiation and clinical status.

Eight reactive lymphatic tissues, 166 cases of non-Hodgkin lymphomas (NHL) and 11 cases of multiple myeloma were investigated for expression of the c-abl protein using the poly-clonal anti-abl antibody 4411 and an indirect peroxidase technique. In selected cases the results were compared to those obtained with a second polyclonal and 2 monoclonal anti-abl antibodies. In 7 cases, Northern blot analysis of abl-mRNA was performed in parallel. In reactive lymphatic tissues, cells positive for the 4411 antibody were confined to the B-cell areas, i.e., to the mantle zone and parts of the germinal center. In NHL, a positive staining of the cell membrane was predominantly detectable in lymphomas putatively originating in the germinal center or mantle zone (in particular in centrocytic NHL), independent of their proliferative activity. Clinically, 7 out of 8 abl-positive cases of chronic lymphocytic leukemia (CLL) had a more aggressive course of disease, whereas "progressive disease" occurred in only 7 out of 19 c-abl antigen-negative cases. When the clinical status of 78 patients with NHL and 11 patients with multiple myeloma was related to c-abl expression, c-abl-positivity was mostly confined to patients in advanced tumor stages [p less than 0.001 (NHL)].

Animals↗
PubMed1988

The biology of interferon actions.

The interferons comprise a group of proteins which were first identified by their ability to protect cells against virus infections. They are synthesized and secreted by a variety of cell types in response to various inducers and exert their effects in vivo by interaction with specific cellular receptors. In this sense the interferons are analogous to polypeptide hormones. In recent years it has become clear that the interferons are capable of influencing cellular physiology and behavior in a number of ways. Their effects include antiviral actions, inhibition of cell growth and proliferation, regulation of the expression of specific genes, modulation of cell differentiation and activation of various cell types in the immune system. This review aims to summarize the current state of biology of interferon actions with special emphasis on the hemopoetic system.

Animals↗
PubMed1988

Interferon-alpha-2 in the treatment of idiopathic myelofibrosis.

We investigated the effect of human recombinant DNA-derived IFN-alpha-2 given in a dose of 1-2 X 10(6) units daily by subcutaneous injection to five patients with advanced idiopathic myelofibrosis (IM). Transfusion dependent anemia and symptomatic splenomegaly were taken as inclusion criteria for this pilot study. Two patients succumbed, one and three months after starting interferon-treatment because of pneumonia and traumatic cranial injury, respectively. While on IFN-treatment no improvement of cytopenia or reduction of splenomegaly was seen in four of the patients. In one patient, however, the requirement for erythrocyte transfusions decreased from 5 to 1.7 monthly upon IFN-treatment. After two, four and six months respectively IFN-treatment had to be stopped in these cases because of progressive thrombocytopenia and/or neutropenia. These observations suggest, that IFN-alpha might be of only marginal value in the treatment of advanced idiopathic myelofibrosis.

Aged↗
PubMed1988

Enhanced serum levels of beta-2-microglobulin, neopterin, and interferon-gamma in patients treated with recombinant tumor necrosis factor-alpha.

The effect of different doses of recombinant human tumor necrosis factor-alpha (rTNF-alpha) on serum levels of neopterin, beta-2-microglobulin and interferon-gamma (IFN-gamma) was investigated in tumor patients. Twelve patients with advanced malignant disease were treated and received single doses of either 1, 10, or 100 micrograms/m2 rTNF-alpha on days 0 and 7. Neopterin, beta-2-microglobulin and IFN-gamma serum levels were measured from day -2 to day 12 of the study. Application of rTNF-alpha leads to a marked and dose-dependent increase of neopterin and beta-2-microglobulin levels; no rTNF-alpha-dependent changes were observed after 1 microgram/m2, and maximum increments were seen in patients receiving 100 micrograms/m2. Serum levels of both parameters peaked after 2 days and returned to baseline values within 1 week. IFN-gamma levels were also elevated after application of rTNF-alpha. We failed, however, to demonstrate a clear correlation between the serum levels of IFN-gamma, beta-2-microglobulin, and neopterin because of the wide range of pre- and posttreatment levels of IFN-gamma. We conclude that neopterin and beta-2-microglobulin represent useful markers for monitoring biological response to treatment with rTNF-alpha.

Adult↗
PubMed1988

In-vitro and in-vivo studies on the induction of neopterin biosynthesis by cytokines, alloantigens and lipopolysaccharide (LPS).

Recently we presented evidence that cellular immune responses are associated with increased in-vitro and in-vivo excretion of neopterin (Huber et al., 1983) and that, in vitro at least, macrophages and IFN-gamma play a key role in the induction of this phenomenon (Huber et al., 1984). Although this marker is increasingly applied for monitoring of human disease, there is limited knowledge about the mechanism(s) responsible for its increased biosynthesis during inflammatory states. To further elucidate this question we evaluated neopterin and IFN-levels in culture supernatants of human blood cells and in patients' sera. Cells or patients were exposed to a panel of recombinant cytokines, alloantigens or lipopolysaccharide. To investigate indirect stimulation by induction of production of endogenous IFNs, the impact of neutralization of IFNs by addition of specific antibodies was also studied. The data confirm our previous results which identified the monocyte/macrophage as the main producer cell among human blood cells. They further demonstrate that, at least in vitro, IFN-gamma, IFN-alpha and LPS can all stimulate neopterin release independently from each other. Thirdly, they indicate that stimuli such as alloantigens or TNF-alpha can indirectly enhance neopterin release by their capacity to induce production of endogenous IFN-gamma. On the basis of these data we conclude that enhanced neopterin biosynthesis does not necessarily relate to activation of T cells but can also be caused by non-immune stimuli.

B-Lymphocytes↗
PubMed1987

Human interferon-gamma increases adhesion of cultured carcinoma cells to the substratum.

Effects of human recombinant-DNA derived interferon-gamma and -alpha 2 on the adhesion of cultured breast cancer cells (BT-20, ZR-75.1, MCF-7, 734-B and Hs-578-T), larynx carcinoma cells (HEP-2), epidermoid carcinoma cells (KB), lung carcinoma cells (CCL 185), and ovarian carcinoma cells (1847) to the surface of cell culture plastic dishes were studied. Layered cells were detached after a 3-day treatment with interferon either by trypsin-EDTA, trypsin, protease or cooling to 4 degrees C. Treatment with interferon-gamma (500 unit/ml) significantly increased the incubation time for trypsin-EDTA, EDTA and at 4 degrees C necessary to bring cells into suspension for the 4 cell lines BT-20, ZR-75.1, MCF-7 and HEP-2. Interferon-alpha 2 was not able to induce a similar effect. Reattachment of interferon-gamma treated ZR-75.1 cells was not increased after harvesting by trypsinization or EDTA action. Decreased adhesion of cultured cells is associated with transformation and the effects of interferon-gamma may be explained by reinforced normal phenotype. Interferon-gamma induced adhesion was not associated with other interferon effects especially the anti-proliferative activity or modulation of surface antigens.

Breast Neoplasms↗
PubMed1987

Interferon-gamma for the treatment of metastatic renal cancer: dose-dependent stimulation and downregulation of beta-2 microglobulin and neopterin responses.

Considering rIFN-gamma as a potent biological response modifier (BRM), we started an open phase II trial with rIFN-gamma in patients with advanced renal cell carcinoma (RCC). For optimization of the dose and schedule of rIFN-gamma, two biochemical serum markers, neopterin and beta-2 microglobulin, were chosen to monitor the biological response. In order to test the magnitude and kinetics of rIFN-gamma-induced neopterin and beta-2 microglobulin release in the serum, rIFN-gamma was administered thrice at three different dose levels in a randomly assigned order (0.01; 0.1; 0.5 mg). Neopterin and beta-2 microglobulin were assessed by means of commercially available radioimmunoassays. The results revealed: 1) strong, reproducible and dose-dependent increments of both markers after the first injection 2) downregulation of the magnitude of neopterin responses with repeated injections at each of the three dose levels tested, and 3) a dose-dependent downregulation of the magnitude of beta-2 microglobulin responses and of serum baseline values at the highest dose level tested. From these data, we conclude that both the dose and schedule might be of importance for optimization of biological responses to exogenously applied rIFN-gamma.

Aged↗
PubMed1987

Characterization of an interferon-resistant mutant of the human breast cancer cell line BT-20.

The human breast cancer cells BT-20 were treated for 18 months in the continuous presence of interferon-gamma (HuIFN-gamma; 500 U/ml). These cells have become completely resistant to HuIFN-gamma and interestingly also to IFN-alpha 2. However, the expression of HLA-DR and the regulation of cell adhesion to tissue culture plastic remained partially under the domain of HuIFN-gamma. A reduced number of IFN-gamma binding sites in comparison to the wild-type cells were observed on the IFN-resistant BT-20 cells.

Breast Neoplasms↗
PubMed1987

Rapid reappearance of large granular lymphocytes (LGL) with concomitant reconstitution of natural killer (NK) activity after human bone marrow transplantation (BMT).

The frequency of large granular lymphocytes and their relationship to functional NK-activity as assessed by the capacity to lyse the K562 tumour target was analysed in five allogenic and two autologous human bone marrow transplant recipients. Date revealed: almost identical disappearance and reconstitution of both parameters further indicating that LGL represent effector cells of spontaneous lysis of K562 targets; a long-lasting suppression of the absolute numbers per ml of blood of both LGL and functional NK activity which we believe was not the consequence of reconstitution with immature effector cells but rather reflected immunosuppressive therapy; LGL exhibits the fastest reappearance rate subsequent to total body irradiation of all populations of circulating leucocytes.

Antigens, Surface↗
PubMed1987

Studies on the optimal dose and the mode of action of alpha-interferon in the treatment of hairy cell leukemia.

The therapeutic efficacy and side effects of alpha-2c-interferon (IFN-alpha 2c) treatment of hairy cell leukemia were compared between two different dose regimen: 10 patients received maximum tolerable doses of IFN-alpha 2c for 1 year (group A), and 11 patients received minimum doses of IFN-alpha 2c, which induced an optimal biological response (group B). Induction of neopterin excretion was chosen as the marker to define biological response and the dose of IFN-alpha 2c applied was on average only one tenth of that in group A cases. Average time of treatment in group B was 42 weeks. The data indicate that both dose levels are effective in the treatment of advanced hairy cell leukemia but that the low dose regimen is free of toxicity. Laboratory investigations on the mechanism of IFN-mediated remission in HCL further revealed that hairy cells are resistant to lysis by IFN-alpha activated large granular lymphocytes and that improved natural killer function subsequent to IFN-alpha treatment in vivo is primarily due to the disappearance of leukemic hairy cells which dilute the natural killer effector cells. These findings support the view of a direct antitumor activity of IFN-alpha as the main therapeutic principle.

Adult↗
PubMed1986

[Interferon-alpha in the treatment of hematologic neoplasms].

This report aims to review briefly the current status of treatment of haematological malignancies with interferon-alpha (IFN-alpha). Overall hairy cell leukemia and chronic myelogenous leukemia appear to be most sensitive to IFN-alpha. We started to investigate, how interferon exerts its antileukemic activity and in which way interferon therapy can be optimized. Our preliminary results fail to support the view of interferon mediated enhancement of host responses. They rather indicate direct effects of IFN on leukemic cells in vitro. By means of IFN-dependent biological markers (e.g. beta-2-microglobulin, neopterin) clinically effective but atoxic doses of IFN-alpha could be defined for HCL and CML. In final conclusion, the recent studies on the clinical efficacy of IFN-alpha revealed its potent antitumoral effect in hematological malignancies. However, the further proof of the potential benefit of IFN treatment versus conventional therapeutic strategies remains to be elucidated.

Cell Division↗
PubMed1986

Alpha-interferon induces remission in hairy cell leukemia without enhancement of natural killing.

The number of large granular lymphocytes (LGL) and the capacity of peripheral blood mononuclear cells (PBMC) to lyse K 562 target cells in a natural killer (NK)-like fashion was evaluated in seven hairy cell leukemia (HCL) patients undergoing treatment with recombinant interferon-alpha-2 (rIFN-alpha-2). In HCL patients, whose peripheral blood showed high numbers (greater than or equal to 15 X 10(3)/microliters) of leukemic cells the number of LGL and their capacity to lyse K 562 tumor target cells were very low prior to treatment but increased significantly (p less than 0.05) following interferon (IFN) therapy. In patients with low numbers of hairy cells (HC) in their peripheral blood, both these parameters were higher and remained largely unaffected throughout IFN treatment. In vitro, HC proved to be completely insensitive to natural killing when tested against unstimulated and IFN-activated LGL from healthy donors. These results fail to support the concept of IFN-mediated enhancement of host antitumor actions, responsible for the favourable clinical results in HCL.

Adult↗