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Biomedical subjects

W Fiedler

Publications and source records attributed to W Fiedler.

At least 73 records · Page 4Linked to original sources
PubMed1996

Use of cryopreserved bone marrow in unrelated allogeneic transplantation.

Cryopreservation of donor bone marrow can facilitate scheduling allogeneic bone marrow transplantation (BMT) by affording independence of a preset time for donation. Previously, we and others have shown the feasibility of using cryopreserved related allogeneic bone marrow. Here, we report the results of the first 10 patients receiving cryopreserved unrelated bone marrow between 1992 and 1995. All evaluable patients (n = 9) engrafted. Time to reach an absolute neutrophil count (ANC) >0.2 x 10(9)/1 and ANC >0.5 x 10(9)/l was 21.4 +/- 9.1 days and 22.6 +/- 9.2 days, respectively. The incidence of acute GVHD > or = grade II and chronic GVHD was 75 and 20%, respectively. Five of nine evaluable patients were alive 100 days post-transplantation. We conclude that cryopreserved unrelated donor bone marrow may be used for allogeneic transplantation.

Adolescent↗
PubMed1996

Changes in telomere lengths in renal cell carcinomas.

Telomeres, the extreme ends of chromosomes, play an important role in chromosome structure and function. The shortening of telomeres is one of the supposed mechanisms of cellular aging and death. Because of end replication problems the length of telomeres decreases with every cell cycle. This may lead to chromosome instability and additional genetic alterations possibly responsible of significant tumor development. In many cancer cells the length of telomeres depends on a balance between the loss of telomeric repeats, at each replication cycle, and the telomere lengthening, by the enzyme telomerase, which is repressed in most normal somatic cells. Many tumor cells demonstrate shortened telomeres in comparison to the corresponding normal tissue. In some types of human cancers the reduction of telomeric repeats was correlated with increasing disease severity. We analyzed Southern blots of HINF1-digested DNA of a large number of renal cell carcinomas (RCC) including different tumor areas, secondary tumors and metastases (76 cases with 142 tumor samples) for changes in the length of telomeric repeats using the oligonucleotide probe (TTAGGG)3 and found telomere shortening in 54%, suggesting that a reduction of the telomeric repeat length is not a general characteristic in RCC. Intratumor heterogeneity was demonstrated in seven cases. But also two RCC, with elongated telomeres in the tumor tissue, were observed. Shortened telomeres do not seem to be associated with advanced stages of tumor development or specific histopathological subtypes of RCC.

Adult↗
PubMed1995

Absence of point mutations in the extracellular domain of the alpha subunit of the GM-CSF receptor in a series of patients with acute myeloid leukemia (AML).

The GM-CSF receptor belongs to the cytokine receptor superfamily. The high-affinity receptors of this class are lacking intrinsic tyrosine kinase domains. The GM-CSF receptor consists of alpha and beta subunits. The beta subunit is shared with the receptors of IL-3 and IL-5. In addition to the membrane bound forms the receptors have been found to possess soluble isoforms. Since retroviral infection of the human GM-CSF dependent cell line, TF-1, leads to factor independent growth by increased expression of the GM-CSF receptor alpha chain in a subgroup of infected clones, we were interested in studying the role of this chain in human AML. Further considering that a point mutation in the extracellular domain of the erythropoietin receptor, also a member of the cytokine receptor superfamily, resulted in constitutive activation of a murine cell line, we investigated the possibility that a point mutation of the GM-CSF receptor was responsible for autonomous growth of AML cells. We sequenced a segment of the receptor coding for the extracellular domain of the alpha subunit. cDNA was prepared from peripheral blood or bone marrow cells from 24 patients with AML, from four patients with MDS and from three human myeloid cell lines. The region of interest was amplified with two rounds of PCR reactions with nested primers, covering five overlapping fragments, and directly sequenced using a non-radioactive technique. No point mutations were found in the investigated samples. Thus, point mutations in this segment of the GM-CSF receptor gene do not seem to play an important role in the transformation process of human acute leukemia.

Base Sequence↗
PubMed1994

Absence of point mutations in a functionally important part of the extracellular domain of the c-kit proto-oncogene in a series of patients with acute myeloid leukemia (AML).

The proto-oncogenes c-fms and c-kit belong to a family of growth factor receptors possessing protein kinase activity. It has been shown that transfection of a c-fms gene carrying a point mutation at codon 301, leads to a ligand-independent transformation of mouse NIH3T3 cells. In human acute myeloid leukemia (AML), point mutations at codon 301 of the c-fms gene have been observed implying an important role in the transformation process. The possibility of a point mutation of the c-kit proto-oncogene was investigated. We sequenced a segment of the c-kit proto-oncogene coding for a part of the extracellular domain. This segment was 40.7% homologous to the c-fms region encompassing codon 301. c-DNA was prepared from peripheral blood or bone marrow cells from 25 patients with AML, from four patients with myelodysplastic syndrome (MDS) and from three human myeloid cell lines. The region of interest was amplified with two rounds of polymerase chain reactions (PCR) with nested primers and directly sequenced. No point mutations were found in the investigated samples. Thus, point mutations in this segment of the c-kit gene do not seem to play an important role in the transformation process of human acute leukemia.

Acute Disease↗
PubMed1993

GCSF gene is expressed but not rearranged in a patient with isochromosome 17q positive acute nonlymphocytic leukemia.

We describe a patient with acute nonlymphocytic leukemia (ANLL) and isochromosome 17q as the sole cytogenetic abnormality. ANNL with i(17q) may represent a distinct entity with certain clinical features, such as male sex, hepatosplenomegaly, and characteristic findings in bone marrow (BM) cytology, including hypercellularity, marked basophilia and eosinophilia, and massive increase in abnormal megakaryocytes. Molecular studies of peripheral blood (PB) cells of our patient, by polymerase chain reaction (PCR) analysis, showed expression of the GCSF gene, which is located on 17q. Southern blots hybridized with a GCSF probe showed no rearrangement of this gene as has been described in some patients with i(17q) positive chronic myeloid leukemia (CML).

Blotting, Southern↗
PubMed1993

Karyotype in multiple myeloma and plasma cell leukaemia.

Between October 1988 and October 1991, 104 patients with multiple myeloma and 6 with plasma cell leukaemia were studied cytogenetically. Abnormal karyotypes were found in bone marrow cells of 33 patients (30%). Most pathological karyotypes were complex with numerous modal and structural anomalies. Numerical anomalies most frequently involved chromosome 11 and structural aberrations occurred most often in chromosomes 1, 11 and 14. The most consistent structural aberration was a 14q+ chromosome (10 patients) resulting from a t(11;14)(q13;q32) in 4 patients and a t(8;14)(q24;q32) in 1 patient. Sequential cytogenetic studies were performed in 15 patients. In 5 of 8 cases with a normal karyotype at diagnosis, chromosomal anomalies were detected when disease progressed. In concomitant cytogenetic/cytological studies it was found that in the majority of patients with normal karyotype the mitoses originated from contaminating normal bone marrow cells. Pathological karyotypes were detected more frequently in pretreated than in untreated patients, in patients with plasma cell leukaemia than in patients with multiple myeloma, in patients with stage III and dense bone marrow infiltration than in patients with stage I. Patients with abnormal karyotype, irrespective if pretreated or not, had a significantly shorter median survival than those with normal karyotype. These findings suggest that karyotype is an independent prognostic factor in multiple myeloma.

Adult↗
PubMed1992

A phase II study of sequential recombinant interleukin-2 followed by dacarbazine in metastatic melanoma.

16 patients with disseminated malignant melanoma (1 with primary ocular melanoma) entered a multicentre phase II study of recombinant interleukin-2, (rIL-2) given by continuous intravenous infusion on days 1-5 at 18 x 10(6) IU/m2 per day, followed by dacarbazine 850 mg/m2 on day 8. After a 2 week rest, a second course was given. In the absence of disease progression, monthly maintenance cycles were given for up to four cycles. 16 patients received one cycle, 14 received two and 6 patients three or more. All 16 patients are evaluable for toxicity and 15 for response. 2 patients responded (13%). 1 patient with lung and pleural metastases achieved partial remission after two cycles and went off treatment after six cycles. 3 months later a complete response was noted lasting 396+ days. A second patient with lung metastases had a partial response lasting 153 days. 3 patients (20%) had stable disease. Mean rebound lymphocytosis (24-48 h after the end of rIL-2 therapy), cell count 4.9 x 10(9)/l (2.6-8.8 x 10(9)/l) was within the expected limits. Other toxicity was as expected. Thus sequential treatment with rIL-2 and dacarbazine is feasible but synergy did not occur.

Adult↗
PubMed1992

Comparison of chromosome analysis and BCL-1 rearrangement in a series of patients with multiple myeloma.

Translocation (11;14)(q13;q32) is a recurring chromosome abnormality which is found non-randomly in non-Hodgkin's lymphoma, especially of follicular type, as well as in B-cell chronic lymphocytic leukaemia, Waldenström's macroglobulinaemia and multiple myeloma. To define further the prevalence of this abnormality in multiple myeloma, we studied a series of 17 patients with this disease with concomitant chromosome analysis and Southern blotting, using a probe specific for the major translocation cluster of the BCL-1 oncogene which is located at chromosome 11q13. Karyotype analysis of 14 evaluable patients revealed three cases with abnormalities of chromosome 11q13, two of them with t(11;14)(q13;q32) and one with del (11)(q13). Southern blot analysis showed no rearrangements in BclI and HindIII digests of DNA from 17 patients including the three patients with anomaly of chromosome 11q13, using a BCL-1 specific probe. A possible restriction length polymorphism was detected in EcoRI cut DNA of five out of 11 patients studied. Therefore the chromosomal break point in our cases with abnormality of chromosome 11q13 must lie outside the major translocation cluster of the BCL-1 gene. However, in centrocytic lymphoma rearrangement of the BCL-1 oncogene has been detected in up to 50% of cases. Location of the break point may therefore be dependent on the differentiation of the transformed B-cell.

Adult↗
PubMed1991

A phase II combination trial with recombinant human tumor necrosis factor and gamma interferon in patients with colorectal cancer.

Recombinant human tumor necrosis factor (TNF) is a cytotoxic monokine with immunomodulatory functions. Gamma interferon (g-IFN) synergizes with TNF in many ways. We therefore conducted a Phase I/II combination trial with TNF and g-IFN at an immunomodulatory dose level in 16 patients with colorectal cancer. TNF (50 micrograms/m2 in a 30 min infusion) and g-IFN (100 micrograms in subcutaneous injections) were administered daily Monday through Friday for 4 weeks. Two cases of major toxicity, one acute renal failure and one case of severe thrombocytopenia, led to discontinuation of study medication in these patients. Toxicities in remaining patients were manageable with conservative treatment. Changes in laboratory values included leukopenia, anemia and thrombocytopenia. Alterations in lipid metabolism and changes in serum levels of acute phase proteins were observed. Increase in both total lymphocytes and a Leu 11 positive subpopulation, as well as an induction of measurable interleukin 2 serum levels in a subgroup of patients, were noted. Response results of 14 evaluable patients were one patient with a mixed response, 4 with stable disease and 9 with disease progression. Median survival was 23.5 weeks with only one patient alive after 71 weeks. Therefore the drug combination of TNF/g-IFN in the chosen regimen cannot be recommended for the treatment of patients with colorectal cancer.

Adult↗
PubMed1991

Translocation (14; 18) and (8; 22) in three patients with acute leukemia/lymphoma following centrocytic/centroblastic non-Hodgkin's lymphoma.

Three patients with centrocytic/centroblastic lymphoma developed a rapidly fatal leukemic transformation of the disease after a transient remission. At the time of transformation, cytogenetic analysis revealed in all patients abnormal karyotypes with coexistence of t (14; 18) and t (8; 22). Molecular analysis in one patient showed rearrangement of the BCL 2 oncogene and c-myc m-RNA expression. These findings imply that translocation t (14; 18) was present during the first phase of the disease and that acquisition of translocation t (8; 22) was accompanied by leukemic transformation.

Acute Disease↗
PubMed1991

New markers for the neurofibromatosis-2 region generated by microdissection of chromosome 22.

To identify new DNA markers around the neurofibromatosis-2 gene on human chromosome 22, the critical region (22q12-q13.1) was microdissected and microcloned from GTG-banded metaphase chromosomes. Eighteen thousand recombinant clones were obtained. Twenty-seven of 55 clones tested (50%) detected single-copy DNA sequences. Nine of nine clones analyzed in detail were found to map to chromosome 22. Interestingly one clone (EAN04) is part of the leukemia inhibitory factor gene which has previously been mapped to 22q11.2-q13.1. Four clones (EAN01, EAN47, EAN57, and EAN68) detect DNA polymorphisms. These probes were used to compare constitutional and tumor genotypes of 41 patients with acoustic neurinoma. Loss of constitutional heterozygosity was identified in 17 of 31 informative cases (55%). From our data we conclude that the microdissection library is a valuable resource for physical and genetic mapping studies in neurofibromatosis-2.

Chromosome Mapping↗
PubMed1990

Mitoxantrone/high-dose Ara-C and recombinant human GM-CSF in the treatment of refractory non-Hodgkin's lymphoma. A pilot study.

Previous study has shown that the combination of mitoxantrone (Novantrone, NO) and Ara-C (AC) (NOAC) was active in refractory non-Hodgkin's lymphoma (NHL) but myelosuppression was dose-limiting. In a pilot study, we investigated the effects of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) after NOAC chemotherapy in patients with refractory NHL. NO was applied at a dosage of 10 mg/m2/day on days 2 and 3 and AC at 3 g/m2/12h on days 1 and 2. RhGM-CSF was administered at 250 ug/m2/day as a continuous i.v. infusion from day 6 until the neutrophils were greater than 3.0/nl for 3 consecutive days. Twenty-three patients from five of the nine participating centers were treated with NOAC chemotherapy plus rhGM-CSF, whereas 14 patients from the other four centers received chemotherapy alone. With rhGM-CSF, the median duration of severe neutropenia (less than 0.5/nl) after NOAC was 8 days versus a median of 13 days without rhGM-CSF (P = 0.0058), and that of thrombocytopenia (less than 20.0/nl), 3 days versus 7 days (P greater than 0.4, NS). The rates of infections and stomatitis were 25% and 17%, respectively, for patients treated with rhGM-CSF as compared to 53% (P = 0.0547, NS) and 60% (P = 0.0078), respectively, without rhGM-CSF. The following side effects were associated with the administration of rhGM-CSF: pleural and/or pericardial effusions in five patients, thrombosis in two patients, bone pain in two patients, and respiratory distress syndrome in one patient. A complete remission was achieved in nine of the 23 patients treated with NOAC plus rhGM-CSF, and in two of the 14 patients treated with chemotherapy alone. The median survival of patients treated with rhGM-CSF was not reached at 400 days and seemed to be longer than that of patients treated with chemotherapy alone (median, 109 days; P = 0.036). RhGM-CSF after chemotherapy can be applied safely to patients with NHL, shorten the period of severe cytopenia, reduce the rates of stomatitis, and did not seem to cause adverse effects on response.

Adolescent↗