Search PubMed⌕ Search

Biomedical subjects

A Ganser

Publications and source records attributed to A Ganser.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Current status of clinical indications for hematopoietic growth factors after chemo-/radiotherapy in gynecology].

With the identification and recombinant production of the hematopoietic growth factors, these cytokines have been evaluated in the treatment of primary bone marrow failure states and following myelosuppressive chemotherapy or radiotherapy. An increasing number of clinical trials with hematopoietic factors have been performed in patients with haematological and oncological diseases. Granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin and, in phase I/II trials, thrombopoietin (TPO) are available for the clinical use. Most studies have been performed with G-CSF and GM-CSF, their beneficial effects are proven regarding acceleration of hematopoietic recovery following chemotherapy. This results in a marked reduction of infectious risks and a shortening of drug- and radiation-induced myelosuppression. CSFs are most important in mobilizing peripheral blood progenitor cells (PBPC) and have allowed high-dose therapy combined with stem cell support in gynecological malignancies, e.g. ovarian carcinoma and breast cancer. However, evidence based, clinical practical guidelines for the use of hematopoietic growth factors in gynecological malignancies are not for all circumstances available.

Chemotherapy, Adjuvant↗
PubMed1997

Treatment with growth factors in myelodysplastic syndromes.

In myelodysplastic syndromes (MDS), pancytopenia leads to a high risk of infectious and hemorrhagic complications. The progression to acute myeloid leukemia adds to morbidity and mortality. While transfusions of red blood cells and platelets are still a cornerstone of the therapy, the clinical use of recombinant hematopoietic growth factors has enlarged the range of therapeutic applications in patients with MDS. It is possible to reverse neutropenia by administration of G-CSF (granulocyte colony stimulating factor) or GM-CSF (granulocyte-monocyte colony stimulating factor). In the case of a severe infection, therapeutic administration of G-CSF together with antibiotics might be justified in otherwise neutropenic MDS patients. Since especially patients with only slight impairment of erythropoiesis and no transfusion dependency have the highest response rates but need erythropoietin (EPO) the least, pharmacoeconomic analyses are urgently needed. Controlled randomized trials will have to ascertain wether combinations of EPO with G-CSF or GM-CSF are of benefit. Clinical studies with thrombopoietin (megakaryocyte growth and differentiation factor) have to be initiated to find out whether thrombocytopenia in MDS can be reversed.

Growth Substances↗
PubMed1996

Gamma delta-T cell-receptor-positive lymphocytes inhibit human hematopoietic progenitor cell growth in HIV type 1-infected patients.

In severe HIV infection, the majority of patients exhibit signs of hematopoietic deficiency including anemia, leukopenia, and thrombocytopenia. Besides other pathophysiological mechanisms, the disturbed helper/suppressor ratio of T-lymphocytes suggests that alterations within T cell subpopulations may have a suppressive effect on HIV-associated hematopoiesis. Since a delta TCS-1- and mostly CD-8-positive subpopulation of cytotoxic T-lymphocytes expressing the gamma delta-receptor is increased in peripheral blood and bone marrow of HIV-infected persons, it was the aim of this study to investigate the role of gamma delta-positive cells in HIV-associated bone marrow deficiency. The number of bone marrow-derived pluripotent colony-forming units (CFU-GEMM), burstforming units-erythrocyte (BFU-E), and colony-forming units-granulocyte-monocyte (CFU-GM) of HIV-1-positive patients was significantly (p < 0.05) increased after depletion of CD-8-positive, gamma delta-positive, and delta TCS-1-positive T-lymphocytes. In contrast, the depletion of these subpopulations had no stimulatory effect in healthy controls. Further experiments identified direct cellular contact between effector and hematopoietic progenitor cells and the production of interferon-gamma and tumor necrosis factor-alpha as the mechanisms mediating the suppressive effect of the delta TCS-1-positive cells in HIV-positive patients.

Adult↗
PubMed1996

Peripheral blood tyrosinase messenger RNA detection and survival in malignant melanoma.

BACKGROUND: The most widely accepted criteria for the evaluation of prognosis of malignant melanoma are histopathologic and clinical presentation. No currently available laboratory tests provide additional prognostic information. It has recently been suggested that reverse transcription and polymerase chain reaction (RT-PCR)-based detection of tyrosinase messenger RNA (mRNA) in peripheral blood might be useful in the early detection of circulating tumor cells, since tyrosinase is thought to be a melanocyte-specific marker. PURPOSE: To further evaluate the clinical relevance of this potential marker, we examined peripheral blood samples from patients with malignant melanoma in different stages of disease for the presence of tyrosinase mRNA. METHODS: Total cellular RNA was extracted from heparinized peripheral blood cells from 64 patients with malignant melanoma, from five healthy control subjects, and from four patients with other cancers using the RNAzol A method. For analysis of tyrosinase mRNA, RT-PCR was performed as previously described by Smith et al.; the sensitivity of this assay was tested using RNA extracted from human melanoma cells (SK-mel 1 and SK-mel 3 cell lines) serially diluted with peripheral blood obtained from healthy control subjects. Two additional human melanoma cell lines (SK-mel 30 and RPMI-7951) served as positive controls for RT-PCR detection of tyrosinase mRNA. Overall patient survival curves were constructed using Kaplan-Meier estimates. RESULTS: Tyrosinase mRNA was detected by RT-PCR assay of all four of the established melanoma cell lines tested. Nine of the 64 patients with malignant melanoma were found to have detectable tyrosinase mRNA in their peripheral blood cells (tyrosinase-positive patients). The 16 patients with localized primary melanoma did not have detectable tyrosinase mRNA in their peripheral blood cells. Among the 48 patients with metastatic disease, all 27 patients who exhibited no evidence of disease progression were tyrosinase negative. Notably, all nine tyrosinase-positive patients had visceral metastases and were found to exhibit disease progression at the time of the sampling. Four of the nine tyrosinase-positive patients were also found to test negative at times without evidence of progressive disease; one patient became negative after achieving stable disease and three became positive for tyrosinase transcripts on disease progression. The probability of survival from time of sampling was significantly lower in the nine tyrosinase-positive patients when tested versus the 23 patients with comparable disease but without detectable tyrosinase mRNA (two-sided; P < or = .05). CONCLUSIONS: The results of this study demonstrate that the detection of tyrosinase mRNA in cells in the peripheral blood by RT-PCR may be a useful prognostic marker for predicting tumor progression and poor clinical outcome in patients with malignant melanoma.

Adult↗
PubMed1996

Improved multilineage response of hematopoiesis in patients with myelodysplastic syndromes to a combination therapy with all-trans-retinoic acid, granulocyte colony-stimulating factor, erythropoietin and alpha-tocopherol.

Differentiation induction therapy is being tested in myelodysplastic syndromes to ameliorate maturation defects and to restore normal hematopoietic function. To this end, 17 patients (eight with refractory anemia, two with refractory anemia and ring sideroblasts, and seven with refractory anemia and excess of blast cells) were treated with a combination of all-trans-retinoic acid (ATRA), granulocyte colony-stimulating factor (G-CSF), erythropoietin (EPO), and alpha-tocopherol for durations of 8-16 weeks. Absolute neutrophil counts increased in all patients; platelet counts increased in five patients with discontinuation of transfusion needs in two of four transfusion-dependent patients. Stimulation of erythropoiesis was seen in eight patients with an increase in hemoglobin concentration in three, a discontinuation of transfusion requirements in another three, and a significant increase in reticulocyte counts as the only parameter in two patients. Clinically important multilineage responses with increases of hemoglobin levels or discontinuation of transfusion needs were thus seen in six patients (35.3%) with three patients having a trilineage response. Serum erythropoietin concentrations did not differ significantly between responders and nonresponders, but the erythroid response was accompanied by a rise in the serum transferrin receptor levels. In the bone marrow, the myeloid-to-erythroid ratio and the maturation index of myeloid cells increased during therapy, while the percentage of blast cells did not change. Cytogenetic analysis demonstrated the persistence of the abnormal clones. Prior to therapy, nonresponders had a significantly higher serum TNF level than responders. Serum concentrations of TNF-alpha and soluble TNF-alpha receptor significantly increased during therapy, but mainly in the patients without an erythroid and platelet response. Soluble IL-2 receptor and soluble ICAM-1 concentrations both increased. This pilot study demonstrates that treatment with ATRA/G-CSF/EPO/tocopherol is well tolerated, leading to normalization of neutrophil counts in most, and to improvement of platelets and red blood cells in a significant subgroup of patients.

Adult↗
PubMed1996

Clinical use of hematopoietic growth factors.

With the identification of recombinant production of the hematopoietic growth factors, these cytokines have been evaluated in the treatment of primary bone marrow failure states and after myelosuppressive chemo- or radiotherapy. Granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and erythropoietin have been approved for clinical use, and others including c-mpl-ligand (also called megakaryocyte growth and development factor or thrombopoietin) are in phase I and II trials. Most studies have been done with granulocyte and granulocyte-macrophage colony-stimulating factors; their beneficial effects are proven regarding acceleration of granulocyte recovery after chemo- and radiotherapy. In the majority of trials, this acceleration results in a reduction of infectious risks, a shortening of drug- and radiation-induced myelosuppression, and a higher chemotherapy dose intensity; however, an improved remission rate and improved long-term survival rates have not yet been definitively documented. Guidelines have been published to provide a rational basis for the use of these factors in clinical practice. It should be emphasized, however, that for many of the recommendations data from randomized clinical trials are lacking.

Acute Disease↗
PubMed1996

Fluorescence in situ hybridization (FISH) is a reliable diagnostic tool for detection of the 9;22 translocation.

The fluorescence in situ hybridization (FISH) technique for detection of the 9;22 translocation was compared with the "gold standard" of conventional cytogenetics. For this purpose, both methods were applied to 81 bone marrow aspirates and/or peripheral blood specimens comprising 50 CML cases and controls from 31 patients without CML. Independently, core biopsies of these 81 patients were investigated by three histopathologists. Conventional karyotype analysis from unstimulated bone marrow cells was successful in 71/81 cases and demonstrated the Ph-chromosome in 42/46 CML patients. With FISH, results were obtained in all 81 cases investigated, confirming fusion of the ber and abl genes in all cytogenetically Ph-positive patients. Among the five Ph-chromosome-negative specimens bcr/abl fusions were detected in only one patient. The percentage of cells found to be Ph-positive by both methods was correlated, but in individual cases considerable differences in the numbers of Ph-positive cells were observed. Different results may be due to selection of cells after in vitro cultivation predominantly. FISH proved to be a very reliable technique for specimens that do not contain dividing cells. With FISH, large numbers of cells can easily be scored which is an advantage compared to conventional cytogenetics. Therefore, this method is particularly suitable for those whose therapy is being monitored or a relapse is suspected. However, the FISH results should be evaluated critically with respect to the practical limit of sensitivity since non-specific fusion signals can also be observed in a small percentage of cells in non-CML cases. It is suggested that each laboratory define its own threshold of bcr/abl fusion signals for diagnosing Ph-positive CML by FISH.

Adolescent↗
PubMed1996

[Myeloproliferative syndromes].

Myelodysplastic syndromes [MDS] are clonal disorders of hematopoietic stem cells leading to a deregulation of proliferation and differentiation of the bone marrow cells. Clinically the patients present with symptoms and signs of anemia, thrombocytopenia, and neutropenia. About a third of the patients will develop acute myeloid leukemia. Supportive care is the mainstay of therapy in these mostly elderly patients. G-CSF should only be given in cases of neutropenia and infection, but not prophylactically. Selected patients with severe or transfusion-dependent anemia will respond to treatment with erythropoietin. In advanced MDS aggressive chemotherapy should be considered, while in patients below 50 years of age and an HLA-identical sibling donor allogeneic bone marrow transplantation is the treatment of choice.

Aged↗
PubMed1996

Effects of Flt3 ligand and interleukin-7 on in vitro growth of acute lymphoblastic leukemia cells.

We investigated the effects of Flt3/Flk-2 ligand (FL) and interleukin-7 (IL-7) on DNA synthesis and proliferation of blast cells from patients with acute lymphoblastic leukemia (ALL). After 7 days of serum-free suspension culture of 19 samples, FL induced maximal DNA synthesis in two cases, whereas the combination of FL and IL-7 did so in another eight samples with a stimulation index (SI) >2. However, the number of viable cells after 7 days of liquid culture decreased in all but one sample. In this case of a pre-pre-B-ALL with a translocation t(4;11), FL induced dose-dependent proliferation (maximal 100 ng/mL) and cells stimulated with FL could be cultured for up to 4 weeks. A homogeneous population with 98% CD19-positive cells was detected before and after culture, and there was no evidence of nonleukemic cell proliferation as determined by immunophenotyping. The flt3 gene was transcribed in all seven cases studied by reverse-transcriptase polymerase chain reaction (RT-PCR). In the ALL cells responsive to FL, the expression of functional Flt3 receptors was confirmed by demonstrating FL-dependent tyrosine phosphorylation of Flt3. Furthermore, FL-dependent tyrosine phosphorylation of cellular proteins of estimated molecular weights of 70, 115, and 140 kD was detectable in these cells. These data demonstrate the functional heterogeneity of ALL samples and show that functional Flt3 receptors capable of mediating FL-dependent mitogenic signaling are expressed in a subset of ALL.

Adolescent↗
PubMed1996

[Current status of the clinical application of hematopoietic growth factors in oncology].

With the identification and recombinant production of the hematopoietic growth factors, these cytokines have been evaluated in the treatment of primary bone marrow failure states and after myelosuppressive chemotherapy or radiotherapy. A lot of clinical trials with hematopoietic factors have been performed in patients with haematologic and oncologic diseases within the last decade. Granulocyte colony-stimulating factor [G-CSF], granulocyte macrophage colony-stimulating factor [GM-CSF], interleukin-3, interleukin-2, erythropoietin and in phase I/II trials thrombopoietin [TPO] are available for the clinical use. At the present, there is a broad use of growth factors. Most studies have been done with G-CSF and GM-CSF, their beneficial effects are proven regarding improvement of hematopoietic recovery after chemotherapy. This results in a marked reduction of infectious risks and a shortening of drug- and radiation-induced myelosuppression. CSFs are most important in mobilizing peripheral blood progenitor cells [PBPC] and have allowed high dose therapy to be given to patients who would not have been able to undergo conventional bone marrow transplantation. However, an improved outcome and improved survival rates with standard chemotherapy protocols couldn't be documented by studies up to now, even though higher chemotherapy doses are possible by the use of hematopoietic factors.

Colony-Stimulating Factors↗
PubMed1996

[Patient education--support--help with decisions: ethical aspects in treatment of amyotrophic lateral sclerosis].

Patients with amyotrophic lateral sclerosis (ALS) develop progressive, degenerative loss of muscle function while retaining mental capacity. This implies special problems of patient information, which should be phase-adapted and patient centered. The difficult task of the physicians requires to provide sufficient information, to enable shared decision-making, without leaving the patient alone. Respiratory failure due to loss of muscle function is often the limiting problem. However, the possible option of ventilatory support opens the question when to stop treatment. It is most important to differentiate between intended mercy-killing and foregoing treatment due to the patient's wish. Discontinuation of treatment is morally justifiable, even required, if the patient refuses further treatment. Advance directives may be helpful to make decisions according to patients' preferences in time.

Amyotrophic Lateral Sclerosis↗
PubMed1996

Exposure to vinblastine modulates beta 1 integrin expression and in vitro binding to extracellular matrix molecules in a human renal carcinoma cell line.

Solitary stroma-invading tumor cells expressing the ATP-binding cassette transporter P-glycoprotein have been reported to be associated with a significantly higher incidence of vessel invasion and lymph node metastases. In contrast to P-gp-mediated multidrug resistance (MDR) which has become well characterized over the last decade, little is known about further morphological and functional alterations in drug-resistant tumor cells. Binding of malignant cells to components of the extracellular matrix mediated by beta 1 integrins has been suggested to play a substantial role in the metastatic cascade. We studied alterations of beta 1 integrin expression and in vitro adhesiveness to extracellular matrix proteins of the human renal carcinoma line Caki-1 in comparison to the vinblastine resistant sublines Caki-1/V1 and Caki-1/V10 (cultured in the presence of 1 ng/ml and 10 ng/ml vinblastine, respectively). Both VLA-1 and VLA-2 receptors were acquired by the Caki-1/V10 subline, whereas untreated and Caki-1/VI cells lacked surface expression of these antigens. VLA-6 was found to be decreased in the vinblastine-resistant sublines. Attachment of drug-resistant Caki-1/V1 and Caki-1/V10 cells to collagen type I was significantly increased when compared to parental cells (p < or = 0.005). Significant differences in the attachment to type IV collagen were observed between Caki-1/V10 and untreated cells (p < or = 0.045). Both Caki-1/V1 and Caki-1/ V10 cells exhibited increased adhesion to fibronectin when compared to cells of the untreated line (p < or = 0.04). Whether an aberrant expression of beta 1 integrin receptors in resistant cells in combination with altered tumor cell adhesiveness is caused by MDR induction or whether it is an epiphenomenon of cytotoxic stress is unknown. Future studies will be needed to characterize the clinical relevance of MDR-associated changes in tumor cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Long-term interleukin-3 and intensive immunosuppression in the treatment of aplastic anemia.

We have assessed in a phase I/II clinical study the tolerability and efficacy of long-term application of recombinant human interleukin-3 (rh-IL-3) in combination with antithymocyte globulin (ATG) and cyclosporin A (CSA) in 13 patients with aplastic anemia who were refractory to or relapsed after previous immunosuppressive treatment. Four cohorts of three patients were consecutively enrolled so that they received rh-IL-3 on days 9, 6, 3 and 1 after start of ATG/CSA treatment. Yeast-derived recombinant human IL-3 was administered by daily subcutaneous injection until day 90 at a dosage of 250 micrograms/m2. Long-term application of rh-IL-3 was well tolerated. The combination of rh-IL-3 with immunosuppression did not modify the known toxicities of ATG and CSA. Incidence and severity of rh-IL-3-related adverse events was less than in other phase I/II trials of rh-IL-3 as single-agent therapy. One might speculate that co-medication with CSA alleviates rh-IL-3-induced side effects. Three of eight patients with refractory AA and all four patients with relapsed AA responded to the combined treatment within four months. The median time to response was 91.5 days. There was evidence for an rh-IL-3-dependent response in two patients. Long-term rh-IL-3 did not cause stem cell exhaustion. One patient died early during the course of the study from EBV-driven lymphoproliferative disease. Two patients developed acute myeloid leukemia 4 and 22 months after cessation of rh-IL-3. In conclusion, long-term rh-IL-3 in combination with immunosuppression is well tolerated. The response rate to the combined treatment in refractory and relapsed AA was high. Recombinant human IL-3-dependent responses suggest efficacy. A prospective randomized trial comparing immunosuppression alone versus a combination with rh-IL-3 is warranted.

Adolescent↗
PubMed1995

Monosomy 7 and activating RAS mutations accompany malignant transformation in patients with congenital neutropenia.

Individuals with severe forms of congenital neutropenia suffer from recurrent infections. The therapeutic use of recombinant human granulocyte colony-stimulating factor (rhG-CSF) to increase the neutrophil count is associated with fewer infections and an improved quality of life. However, the long-term effects of this new therapy are largely unknown. In particular, it is unclear if myeloid leukemia, a known complication of some forms of congenital neutropenia, will occur with increased frequency among patients who receive long-term treatment with hematopoietic growth factors. We report 13 patients with congenital disorders of myelopoiesis who developed leukemic transformation with either myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML) and 1 who acquired a clonal cytogenetic abnormality without evidence of MDS or AML while receiving rhG-CSF. The bone marrows of 10 patients showed monosomy 7 and 5 had activating RAS mutations. These abnormalities were not detected in pretreatment bone marrows and cessation of rhG-CSF was not associated with either clinical improvement or cytogenetic remission. We conclude that patients with severe forms of congenital neutropenia are at relatively high risk of developing MDS and AML. The occurrence of monosomy 7 and RAS mutations in these cases suggests that the myeloid progenitors of some patients are genetically predisposed to malignant transformation. The relationship between therapeutic rhG-CSF and leukemogenesis in patients with severe chronic neutropenia is unclear.

Adolescent↗