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E Lengfelder

Publications and source records attributed to E Lengfelder.

At least 37 records · Page 2Linked to original sources
PubMed1999

Diagnosis, pathogenesis and treatment of the myeloproliferative disorders essential thrombocythemia, polycythemia vera and essential megakaryocytic granulocytic metaplasia and myelofibrosis.

According to strict clinical, hematological and morphological criteria, the Philadelphia (Ph) chromosome negative chronic myeloproliferative disorders essential thrombocythemia (ET), polycythemia vera (PV), and agnogenic myeloid (megakaryocytic/granulocytic) metaplasia (AMM) or idiopathic myelofibrosis (IMF) are three distinct disease entities with regard to clinical manifestations, natural history and outcome in terms of life expectancy. As clonality studies have clearly demonstrated that fibroblast proliferation in AMM, as well as in many other conditions such as advanced stages of Ph(+)-essential thrombocythemia, Ph(+)-granulocytic leukemia, and Ph(-)-polycythemia vera, is polyclonal indicating that myelofibrosis is secondary to the megakaryocytic granulocytic metaplasia in these various conditions, AMM is illogically labeled as IMF. As abnormal megakaryocytic granulocytic metaplasia is the essential feature preceding the early prefibrotic stage of AMM, the term essential megakaryocytic granulocytic metaplasia (EMGM) can readily be used to characterize this condition more appropriately at the biological level. Clinical, hematological and morphological characteristics, in particular megakaryocytopoiesis and bone marrow cellularity, reveal diagnostic features, which enable a clear-cut distinction between ET, PV and EMGM or classical IMF. The characteristic increase and clustering of enlarged megakaryocytes with mature cytoplasm and multilobulated nuclei and their tendency to cluster in a normal or only slightly increased cellular bone marrow represent the hallmark of ET. The characteristic increase and clustering of enlarged mature and pleiomorphic megakaryocytes with multilobulated nuclei and proliferation of erythropoiesis in a moderate to marked hypercellular bone marrow with hyperplasia of dilated sinuses are the specific diagnostic features of untreated PV. EMGM, including the early prefibrotic stages as well as the various myelofibrotic stages of classical IMF appear to be a distinct neoplastic dual proliferation of abnormal megakaryopoiesis and granulopoiesis. The histopathology of the bone marrow in prefibrotic EMGM and in classical IMF is dominated by atypical, enlarged and immature megakaryocytes with cloud-like immature nuclei, which are not seen in ET and PV at diagnosis and during follow-up. Myelofibrosis in ET, PV and EMGM is graded into: no reticulin fibrosis (MF0), early reticulin fibrosis (MF1), advanced reticulin sclerosis with minor or moderate collagen fibrosis (MF2) and advanced collagen fibrosis with osteosclerosis (MF3). Myelofibrosis is not a feature of ET at diagnosis and during long-term follow-up. Myelofibrosis may be present in a minority of PV-patients at diagnosis and usually becomes apparent during long-term follow-up in the majority of PV-patients. Myelofibrosis secondary to the abnormal megakaryocytic and granulocytic myeloproliferation constitutes a prominent feature in the majority of EMGM/IMF at time of diagnosis and usually progresses more or less rapidly during the natural history of the disease. Life expectancy is normal in ET, normal during the 1st ten years and compromised during the 2nd ten years follow-up in PV, but significantly shortened in the prefibrotic stage of EMGM as well as in the various myelosclerotic stages of classical IMF. First line treatment options in prospective randomized clinical trials of newly diagnosed MPD-patients are control of platelet function with low-dose aspirin versus reduction of platelet count with anagrelide, interferon or hydroxyurea in ET; control of platelet and erythrocyte counts by interferon alone versus bloodletting plus hydroxyurea on indication in PV; interferon versus no treatment in the early stages of EMGM; a wait and see strategy in the fibrotic stages of EMGM or classical IMF with favorable prognostic factors, and bone marrow transplantation in classical IMF with poor prognostic factors at presentation or during short-term follow-up.

Aspirin↗
PubMed1999

Microsatellite instability and loss of heterozygosity in radiation-associated thyroid carcinomas of Belarussian children and adults.

DNA from 129 paired thyroid tumorous and non-tumorous tissue samples of Belarussian children (102 patients; age at surgery </=18 years) and adults (27 patients; age at surgery 19-35 years), who had been exposed to radioactive fallout from the Chernobyl reactor accident in 1986, was examined for microsatellite instability (MSI) and loss of heterozygosity (LOH). Twenty-eight microsatellite markers were chosen because of their vicinity to DNA repair genes or genes involved in tumorigenesis as well as regions of chromosomal breakpoints in thyroid tumours. In 40 patients (31% of 129) we detected a total of 73 alterations, 80% of which were classified as LOH and only 20% as MSI. Amongst these 40 patients we identified a subgroup of 11, mainly young female patients (8.5% of 129), exhibiting alterations in at least two microsatellite markers. For comparison we examined samples from spontaneous thyroid carcinomas without radiation history from 20 adult patients from Munich (mean age at surgery 56 +/- 13 years). None of the tumour samples investigated showed evidence of alterations in the 28 microsatellite markers tested. Taken together our data indicate an increased instability of microsatellite markers in thyroid cancers from Belarussian patients. At present, it is uncertain whether the increased genome instability observed in Belarussian patients is the result of the exposure to radioactive iodine from the Chernobyl reactor accident or due to the young age of the patients.

Adolescent↗
PubMed1998

Molecular analysis of new subtypes of ELE/RET rearrangements, their reciprocal transcripts and breakpoints in papillary thyroid carcinomas of children after Chernobyl.

A high prevalence of RET rearrangements is found in papillary thyroid carcinomas (PTC) of children from Belarus after the Chernobyl reactor accident. The ELE/RET rearrangement (PTC3) is prevailing. Aberrant types of ELE/RET rearrangement have been found with a truncated ELE1 gene: As compared with the common form (PTC3r1) one aberrant type is shorter by one 144 bp exon (PTC3r2) (three cases); in the second atypic form (PTC3r3) the ELE1 part is 18 bp shorter than in PTC3r1. In agreement with the observation that the oncogenic RET is generated by a paracentric inversion at chromosome 10, we found not only ELE/RET, but also RET/ELE transcripts in these tumors. Sequencing of the breakpoint regions at the genomic DNA level revealed DNA modifications that might be relevant for illegitimate recombination after DNA doublestrand breaks. The high prevalence of ELE/RET rearrangements and various subtypes appears to be typical for radiation-induced thyroid carcinomas of children after the Chernobyl reactor accident.

Artificial Gene Fusion↗
PubMed1998

Detection of a novel type of RET rearrangement (PTC5) in thyroid carcinomas after Chernobyl and analysis of the involved RET-fused gene RFG5.

A novel type of RET rearrangement, PTC5, was detected in papillary thyroid carcinomas of two patients exposed to radioactive fallout after Chernobyl. Reverse transcription-PCR and rapid amplification of 5'-cDNA ends revealed a fusion of the ret tyrosine kinase (TK) domain with a sequence identical to that described previously as ret-II. Ret-II is a transfection artifact in NIH3T3 cells and has not yet been detected in any human tumor. Overlapping sequences found in the expressed sequence tag databases enabled us to sequence the COOH terminus of the ret-fused gene 5 (RFG5). The combined data made it possible to assemble a full-length rfg5 protein sequence. Computer-assisted analysis of this sequence reveals four putative coiled-coil structures, possibly involved in dimerization, but no membrane-binding sequences. Northern blots show a ubiquitous RFG5 expression in various normal tissues, including the thyroid gland. In addition to the RFG5/RET, we also detected the reciprocal RET/RFG5 transcript in both tumor samples, suggesting that the rearrangement is based on a balanced reciprocal translocation. In agreement with other rearranged TKs, it is concluded that the transforming action of the new fusion protein rfg5/ret in thyroid tumors may be due to an activation of the ret TK by constitutive expression and dimerization potential of the 5'-fused rfg5 protein. Ret immunohistochemistry indicates that the fusion protein is expressed in all cells of PTC5 tumors, suggesting that RFG5/RET rearrangement is an early event in thyroid carcinogenesis.

Adult↗
PubMed1998

Should a platelet limit of 600 x 10(9)/l be used as a diagnostic criterion in essential thrombocythaemia? An analysis of the natural course including early stages.

In order to evaluate the natural history of essential thrombocythaemia (ET), clinical data and prognostic factors of 143 patients with ET were retrospectively analysed (mean observation time 6.1 +/- 4.6 years). In 42 patients the early phase of the disease with initial platelet counts between 250 and 600 x 10(9)/l was assessed. In most early cases, ET was suggested by clinical symptoms (79%) and increased megakaryopoiesis (95%) with abnormal megakaryocytes in bone marrow histology (n = 34) and cytology (n = 5). Other myeloproliferative disorders and reactive thrombocytosis were excluded according to the diagnostic criteria of the Polycythemia Vera Study Group. During follow-up of the 38 early cases not treated cytoreductively at diagnosis, the platelet counts increased to >600 x 10(9)/l in 28 patients (74%) and remained between 450 and 600 x 10(9)/l in 10 patients (26%). In primarily asymptomatic patients (n = 46) with initial platelet counts above (n = 37) and below 600 x 10(9)/l (n = 9) the rates of increase of symptomatic patients were similar at about 7% per year. No influence of the initial platelet count on survival was seen in multivariate analysis of prognostic factors which included all 143 cases. Survival was mainly influenced by the rate of ET-related complications during follow-up (P = 0.002). Analysing the influence of cytoreductive therapy on symptom-free survival, platelet reduction benefited patients under 60 years (19 cytoreductively treated v 65 untreated patients, P = 0.075). The results demonstrate the possible clinical relevance of the early stages of ET and suggest that the features of pathologic megakaryopoiesis in the bone marrow are a more reliable diagnostic criterion than a definite platelet limit. Therefore, further therapeutic studies should include all stages of the disease and all age groups.

Adult↗
PubMed1998

Correlation of cytogenetic, molecular cytogenetic, and clinical findings in 59 patients with ANLL or MDS and abnormalities of the short arm of chromosome 12.

Abnormalities of the short arm of chromosome 12 (12p) are found in about 5% of acute nonlymphocytic leukaemias (ANLL) and myelodysplastic syndromes (MDS). They are described to be characteristic of secondary leukaemias, especially after prior mutagenic exposure, and to be associated with a poor prognosis. In our series of 59 patients with 12p abnormalities and ANLL or MDS, exposure to genotoxic agents was proven only in five patients, but in 13/44 patients ANLL evolved from an MDS. Patients with a small deletion del(12)(p11.2p13) having a mild clinical course were distinguished from those with a large del(12)(p11.2), additional chromosomal anomalies, and a poor clinical course. Among the 31 patients with translocations or dicentric chromosomes involving 12p, a group of eight with t/dic(12;13) was the most frequent and was associated with a poor prognosis. The clinical outcome was adverse in the majority of patients with complex karyotype abnormalities, but in some patients a milder clinical course seems likely. A new, hitherto undescribed, abnormality in an MDS case with a duplication dup(12)(p11.2p13) was the amplification of the signal of the yeast artificial chromosome (YAC) clone 964c10 (D12S736). In 38 cases with deletions or unbalanced translocations/dicentrics one YAC signal was lost. Five patients with balanced translocations demonstrated breakpoints within the YAC, containing the ETV6 (TEL) gene. The breakpoints were telomeric to the YAC 964c10 in seven cases and centromeric in one patient.

Adult↗
PubMed1997

p53 mutations in childhood thyroid tumours from Belarus and in thyroid tumours without radiation history.

Mutations in the p53 tumour-suppressor gene (exons 5-8) were investigated in 31 Belarussian childhood thyroid tumours (24 cases of papillary thyroid carcinoma, 3 benign tumours and 2 cases each of thyroiditis and goiter); 33 thyroid tumours from juveniles and adults without radiation exposures (25 carcinomas of various histological types, including 11 papillary carcinomas and 8 adenomas) and 6 tumours from adults (4 papillary carcinomas, 1 adenoma, 1 goiter) served as controls. The mutational spectrum of p53 differed greatly between the childhood thyroid carcinomas from Belarus and the control groups. In the control groups of 29 malignant thyroid tumours, 7 different mutations were detected on exons 5-8, none of which occurred among the 15 papillary carcinomas in this group. Five mutations were found in tissue samples of the 24 childhood papillary carcinomas, and they were all the same p53 point mutation (CGA --> CGG) on codon 213 of exon 6. To determine whether this mutation is simply a polymorphism or whether it is specific to the tumour cells, laser-assisted microdissection was applied to collect various areas of tumorous and non-tumorous cells (10-20 cells per sample) from each paraffin-embedded tissue section of 8 of the papillary thyroid carcinomas. Using PCR-SSCP and sequence analysis on these cells, the very same p53 mutation on codon 213 was detected in various microdissected tumour samples of 2 cases, but it was not found in any microdissected non-tumorous sample. The exclusive occurrence of this p53 mutation in selective microdissected samples of tumour cells, even as homozygous mutation in 1 case, reflects a distinct tumour heterogeneity within papillary childhood thyroid carcinomas.

Adolescent↗
PubMed1997

Randomized studies with interferon in chronic myelogenous leukemia (CML) and comparative molecular aspects. German CML Study Group.

Four randomized prospective studies on interferon alpha (IFN) in CML report varying degrees of prolongation of the chronic phase of CML and of survival as compared to conventional therapies. There is agreement that IFN prolongs survival as compared to standard busulfan. There is disagreement, however, as to which degree IFN is superior to hydroxyurea. Whereas the randomized studies of the Italian cooperative group and of the British MRC find a statistically significant survival advantage of IFN over hydroxyurea of about 20 months, this difference is only 10 months in the German randomized study and not significant. One reason for this difference might be the more intensive treatment schedule for the hydroxyurea control group in the German study. Other reasons might be differences in risk profiles between the patient groups studied and in strategies of IFN therapy. About 1% of the human genome consists of retroviral or retroviral-like sequences. By analogy to animal models, endogenous retroviruses might also have pathogenic potential in human disease. The transposon-like structure of retroviruses that enables them to integrate at almost any position in the host genome and the capability of retroviruses to serve as efficient vehicles of cellular genes are in support of a pathogenic potential. Furthermore, particles resembling retroviruses have been observed long ago in human embryonic and malignant tissues and cell lines. Sequence information and the transcriptional activity of the endogenous sequences argue against the possibility that these sequences are only fossil relics of early evolutionary periods. Most of the sequences appear to be inactivated by stop codons or frameshifts, making the genomic localization of open reading frames with biological activity difficult. Up to now, mutagenesis by insertion of retroviral-like sequences in sporadic cases of human disease appears to be the only example of pathogenic relevance of retroviruses in man.

Antineoplastic Agents↗
PubMed1996

A new form of RET rearrangement in thyroid carcinomas of children after the Chernobyl reactor accident.

Intrachromosomal rearrangements involving the RET and the adjacent H4 or ELE1 gene are very frequent events in thyroid cancer of children from Belarus after the Chernobyl reactor accident (Klugbauer et al., 1995). The fusion product between ELE1 and RET (RET/ PTC3) seems to be the prevailing type of rearrangement as shown in a recently published study using a novel RT multiplex PCR approach in combination with the identification of the rearrangement type by RT-PCR and direct sequencing. Now we found a new type of RET rearrangement: By the 5'RACE method we demonstrated in cDNA the fusion of the tyrosine kinase domain of RET with a truncated ELE1 gene shorter than the ELE1 in RET/PTC3. Sequencing of genomic DNA revealed a rearrangement breakpoint at position 41 of a new ELE1 intron (522 bp in length). The new oncogene RET/ delta PTC3 is shortened by one ELE1 exon of 144 bp in length. Structural considerations of the ele1 amino terminal of RET/ delta PTC3 suggest that the transforming activity of the fusion protein is apparently not affected by this truncation. The exon lacking in RET/ delta PTC3 was found to code in the reciprocal transcript RET/ delta ELE1 and increased its size by 144 bp. Obviously the new and possibly additional ELE/RET fusion molecules might even increase the high prevalence of ELE1/RET rearrangements in thyroid carcinomas of children after the Chernobyl reactor accident.

Amino Acid Sequence↗
PubMed1996

Incidence and implication of additional chromosome aberrations in acute promyelocytic leukaemia with translocation t(15;17)(q22;q21): a report on 50 patients.

Acute promyelocytic leukaemia (APL) is characterized by the translocation t(15;17)(q22;q21). Usually t(15;17) is the sole cytogenetic abnormality, but some patients show other chromosome aberrations in addition to t(15;17). The influence of additional chromosome aberrations on the clinical outcome of patients with t(15;17) is unclear. We have analysed 50 cases of APL carrying the translocation t(15;17). Additional chromosome aberrations were observed in 17/47 patients (36%) studied at initial diagnosis and in all three patients studied at relapse. In nine cases (18%) an additional chromosome 8 and in six cases (12%) an isochromosome of the long arm of the derivative chromosome 17 was observed. Various structural rearrangements in addition to t(15;17) were detected in nine patients (18%). Clinical follow-up data were available for 44 patients studied at diagnosis. A complete remission (CR) was achieved in 34 patients (77%). 10 patients (23%) died within 1 month after diagnosis due to infection or bleeding, eight (24%) relapsed within 10-18 months after initial diagnosis. 28 patients are alive 2-93 months after diagnosis (25 in first CR, two in second and one in third CR) (median follow-up 18.5 months). Bone marrow transplantation was performed in six patients (three in first CR, two in second CR, one in third CR), all are alive and in CR. An influence of secondary chromosome anomalies on prognosis was not observed. However, if a higher rate of long-term remission can be reached, specific secondary chromosome aberrations might turn out to be of prognostic value.

Adolescent↗
PubMed1996

Chromosome translocations in thyroid tissues from Belarussian children exposed to radioiodine from the Chernobyl accident, measured by FISH-painting.

Chromosome painting of chromosomes 1, 4 and 12 was performed on metaphase preparations of cultured thyroid cells to analyse the frequency of radiation-induced stable chromosome translocations in papillary thyroid carcinomas from 40 Belarussian children exposed to radioiodine from the Chernobyl accident, and from 31 reference case. As expected, we found the highest translocation frequencies in secondary thyroid tumours after radiotherapy, but there were also high frequencies in tumour tissues as well as in non-tumourous tissues from childhood papillary carcinoma samples from Belarus. Among the Belarussian tumours the cases from the Gomel region exhibited the highest frequency of translocations and five cases lie within the range of frequencies observed in secondary thyroid tumours after radiotherapy. The findings support the assumption that radiation was the principal cause of the tumours in Belarus, but they indicate also that only a minority of the Belarus cases, which have developed papillary carcinomas, were exposed to very high doses of radioiodine.

Adolescent↗
PubMed1996

Interferon-alpha in the treatment of essential thrombocythemia.

Interferon alpha (IFN) inhibits the growth of megakaryocytic progenitors in normal hematopoiesis and in patients with essential thrombocythemia (ET) leading to a reduction of peripheral platelet counts. The effectiveness in the induction therapy of patients with ET is demonstrated in 11 international studies including 212 patients. With an average dose of about 3 mill IU IFN daily, the response rate was about 90%. Further studies investigated the practicability and the success of IFN maintenance therapy. The results show that IFN can effectively control platelet counts over a period of several years. During maintenance the IFN dose could be reduced in the majority of patients. However, sustained unmaintained complete remissions were obtained in only 12% of the patients. Side effects were frequently the limiting factors in treatment with IFN especially in older patients. Analyzing a total of 273 patients, IFN therapy was terminated in 25% against the primary treatment plan. Of the currently effective drugs in controlling the platelet counts in ET, IFN is the only antiproliferative agent with immuno-modulating properties. Thus far, no leukemogenic or significant gonadotoxic effects have been observed. In a subset of the patients off all therapy, the sustained remissions support a long-term tumor load reduction effect by IFN. Thus, IFN is a promising agent in cytoreductive treatment of ET especially in younger patients.

Bone Marrow↗
PubMed1996

The superoxide dismutase-mimic copper-putrescine-pyridine suppresses lipid peroxidation in CHO cells. Implications for its prooxidative and antioxidative mechanisms of action.

Copper-Putrescine-Pyridine (Cu-PuPy) is a membrane-permeable complex which efficiently dismutates superoxide. In excess of 0.1 mM it is highly cytotoxic and oxidizes cellular GSH with concomitant production of H2O2. Here we show that treatment of CHO cells with 0.2 mM Cu-PuPy (0-200 min) leads to an accumulation of H2O2. Organic hydroperoxides which are also formed at low levels in the present of Cu-PuPy, increase significantly after removal of the copper complex. We conclude that Cu-PuPy acts as an oxidant until cellular GSH is depleted. However, by interfering with radical chain propagation reactions, it suppresses lipid peroxidation and thus substitutes for consumed physiological antioxidants in a later stage of treatment. This consistently explains our previous, seemingly paradox, finding that longer Cu-PuPy treatments may be significantly les toxic than shorter ones.

Animals↗
PubMed1996

Fifty-one patients with acute myeloid leukemia and translocation t(8;21)(q22;q22): an additional deletion in 9q is an adverse prognostic factor.

The translocation t(8;21)(q22;q22) occurs in 6 to 12 percent of patients with AML, and usually predicts a good response to chemotherapy with a high remission rate and a relatively long median survival. The influence of additional chromosome aberrations on the clinical outcome of patients with t(8;21) is unclear. We analyzed 51 cases of acute myeloid leukemia carrying a translocation t(8;21)(q22;q22); 23 female and 28 male patients. The complete remission rate was 92 percent and median overall survival was 52.4 months. The median overall survival of female patients was significantly worse than of male patients (37.2 months vs not reached, P = 0.025). Additional chromosome aberrations were detected in 41 patients at diagnosis (80 percent), 31 (61 percent) had lost a sex chromosome, seven (14 percent) showed a partial deletion of the long arm of chromosome 9 and in three patients (6 percent) a gain of chromosome 8 was observed. Whereas the loss of a sex chromosome had no influence on prognosis, a partial deletion of the long arm of chromosome 9 was an unfavorable prognostic factor. The median overall survival of the seven patients with del(9q) was only 12.5 months and thus significantly shorter than in patients with only t(8;21) or with t(8;21) and additional sex chromosome loss (median survival not reached: P = 0.0010).

Acute Disease↗
PubMed1996

Intensive combination chemotherapy in treatment of CML.

Tumor load reduction has an influence on survival of patients in the chronic phase of chronic myelogenous leukemia (CML). This comprises both reduction of white blood cell (WBC) mass and reduction of the Philadelphia (Ph)-positive clone. Besides drug monotherapy, intensive combination chemotherapy is also very effective in reducing tumor burden in the chronic phase of CML. Therapeutic concepts consisting of combination chemotherapy include intensive chemotherapy alone or in combination with interferon-alpha (IFN-alpha) and preparative regimens before autografting or allografting. All these concepts demonstrate the effectiveness of this treatment form. The high toxicity of combination chemotherapy does not justify its application in unselected patients. However, in suitable patients, possibly in poor interferon-alpha responders (as carried out in the current German CML study) it might be superior with regard to survival.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

High prevalence of RET rearrangement in thyroid tumors of children from Belarus after the Chernobyl reactor accident.

RET rearrangement was studied in papillary thyroid carcinomas (PTC) of children exposed to radioactive fallout in Belarus after the Chernobyl accident. To detect RET rearrangement in small tissue samples from thyroidectomy specimen (12 PTC of children; 2 PTC and 1 follicular carcinoma of adults; non-tumorous thyroid tissue of 4 children and 4 adults as controls), a RT-multiplex PCR was developed using primers suited to amplify fragments in different quantities depending on the presence or absence of RET rearrangements in the tissues. The type of rearrangement was determined by RT-PCR and direct sequencing using primers for ret/PTC1, 2 and 3. Two-thirds of the papillary thyroid carcinomas of the children revealed a RET rearrangement, with ret/PTC3 being more frequent by a factor of 3 than ret/PTC1. ret/PTC2 was not detected. All RET rearrangement-positive tumors had lymph node metastasis while half of the tumors with wild-type cRET had not. More than half of the cases with ret/PTC3 expressed not only the ELE/RET transcript as expected, but also the RET/ELE transcript. Intrachromosomal rearrangement involving RET and the adjacent H4 or ELE gene on chromosome no. 10 is a very frequent event in thyroid cancer of children of the Chernobyl-contaminated zone of Belarus.

Adult↗