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Biomedical subjects

R Becher

Publications and source records attributed to R Becher.

At least 55 records · Page 3Linked to original sources
PubMed1993

Clinical aspects of acute myeloid leukemias of the FAB types M3 and M4Eo. The AML Cooperative Group.

Acute promyelocytic leukemia (AML FAB M3, APL) and acute myelomonocytic leukemia with abnormal eosinophils (AML M4Eo) are considered distinct entities with characteristic clinical, morphological, cytogenetic, and prognostic features. Promyelocytic leukemia is characterized by abnormal promyelocytes replacing normal hematopoiesis associated with a translocation between the long arms of chromosomes 15 and 17 t (15; 17), severe coagulopathy, and responsiveness to all-trans retinoic acid (tretinoin). Characteristic features of AML M4Eo are a myelomonocytic marrow infiltration, eosinophils with abnormal immature granules positive for chloroacetate esterase, an inversion or translocation of chromosome 16, and an increased risk of meningeal relapses. Prognosis of both types of AML has been reported to be better than prognosis of the other entities combined. Since most of the published data were collected from heterogeneous patient populations treated with various chemotherapeutic regimens, we have analyzed treatment outcome of AML M3 and M4Eo in the AMLCG-85 study for patients younger than 60 years. For the total population of 594 patients of this study, CR rate was 68.89%, early death rate 11.60%, and no or partial remission was achieved in 19.51% of the cases. Of 40 patients with AML M3 or M3 v complete remission was attained in 62.5%. Nine patients died within 42 days after the start of antileukemic therapy (22.5%). Of these nine, four died because of infection, five because of bleeding. Relapse-free survival rate was 59% after 3 years, significantly better than the respective curve of the other FAB types combined (35% after 3 years). In AML M4Eo, 91.7% of the 24 patients reached complete remission. The early death rate was 8.3%. No case of nonresponse was seen. Relapse-free survival rate was 49% after 3 years compared with 35% for the other types combined.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Chemically induced DNA damage in isolated rabbit lung cells.

By use of an isolation procedure including centrifugal elutriation and density gradient centrifugation, relatively pure fractions of Clara cells and type II cells were obtained from rabbit lungs. These cells and alveolar macrophages isolated by lavage were exposed to methyl methanesulfonate (MMS), 1,2-dibromo-3-chloropropane (DBCP), 1-nitropyrene (1-NP), 2-nitrofluorene (2-NF), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N'-nitrosonornicotine (NNN), N-nitrosoheptamethyleneimine (NHMI) or phorbol 12-myristate 13-acetate (TPA). DNA damage measured as alkali-labile sites and/or single-strand breaks was then determined in the different lung cells by an automated alkaline elution system. The direct-acting compound MMS showed similar DNA-damaging effect in Clara cells, type II cells and alveolar macrophages. The nematocide DBCP, activated by both P450- and glutathione S-transferase(s)-dependent pathways, caused considerably less DNA damage in macrophages than in Clara or type II cells. Similar differences between the lung cells in induction of DNA damage as observed with DBCP were demonstrated after exposure to the activation-dependent nitrosamines NNK and NHMI and the tumor promoter TPA. The other test substances (1-NP, 2-NF, NNN) did not cause any marked DNA damage measured by the alkaline elution technique. These findings are in agreement with the known metabolic capacity of these cell types, indicating that Clara and type II cells are possible primary targets for lung toxic/carcinogenic compounds.

Animals↗
PubMed1993

Delineation of translocation t(15; 17) in acute promyelocytic leukemia by chromosomal in situ suppression hybridization.

In this study we demonstrate the feasibility of chromosomal in situ suppression (CISS) hybridization to detect the translocation t(15; 17) in metaphase spreads of patients with acute promyelocytic leukemia. Using DNA libraries from sorted human chromosomes 15 and 17 the translocation t(15; 17) can be unequivocally identified even if the spread and the morphology of the chromosomes are poor. The sensitivity of CISS hybridization is compared with the sensitivity of conventional G-banded karyotypes.

Adult↗
PubMed1993

Analysis of the p53 gene in patients with isochromosome 17q and Ph1-positive or -negative myeloid leukemia.

Increased incidence of p53 gene aberrations or chromosome 17p monosomy resulting from an isochromosome 17q [i(17q)] has been observed with transition of chronic myelogenous leukemia (CML) to myeloid blast crisis (BC), and in some patients with poor risk acute myeloid leukemia (AML) progressing from myelodysplastic syndrome (MDS). These data suggested that disease progression may be linked to bi-allelic inactivation of p53. Here, we report on p53 gene analyses of nine patients with CML-BC and AML who showed an i(17q) as characteristic cytogenetic anomaly. Using Southern blots, agarose gel electrophoresis and single-strand conformation polymorphism analyses of PCR products from genomic DNA and cDNA, spanning exons 4 through 9, we did not detect any structural abnormalities of the remaining p53 allele. These findings question the hypothesis that p53 gene alterations are the principal molecular event responsible for progression of CML chronic phase or MDS to i(17q)-positive CML-BC or AML, respectively.

Adult↗
PubMed1993

Genotoxic effects of cyclopenta-fused polycyclic aromatic hydrocarbons in isolated rat hepatocytes and rabbit lung cells.

Benz[j]aceanthrylene (B[j]A) and benz[l]aceanthrylene (B[l]A), two isomeric cyclopenta polycyclic aromatic hydrocarbons (CP-PAH) structurally related to 3-methylcholanthrene, were studied with respect to their genotoxic effects in isolated liver and lung cells. Both compounds were found to cause DNA adducts measured by the 32P-postlabelling technique. The level of DNA-adducts in rat hepatocytes exposed to 30 micrograms/ml B[l]A and B[j]A for 4 h were 46.5 +/- 22.0 and 8.3 +/- 5.1 fmol/micrograms DNA respectively. Using butanol extractions, the major and one of the minor B[j]A adducts co-chromatographed with B[j]A-1,2-oxide adducts of 2'-deoxyadenosine and 2'-deoxyguanosine. Thus, oxidation at the cyclopenta-ring of B[j]A appears to be an important activation pathway. In hepatocytes, 3-30 micrograms/ml of B[j]A and B[l]A induced DNA damage and repair measured both as increased alkaline elution of DNA and as increased incorporation of [3H]TdR in the DNA. B[l]A was somewhat more potent than B[j]A in inducing DNA repair. Reactive CP-PAH intermediates formed in the hepatocytes caused mutations in Salmonella typhimurium TA98 upon co-incubation. DNA adducts were also observed in isolated rabbit lung cells exposed to 30 micrograms/ml B[l]A or B[j]A for 2 h. A total of 14.5 +/- 6.9, 2.9 +/- 2.1 and 0.2 +/- 0.6 fmol B[l]A adducts/micrograms DNA were observed in Clara cells, type II pneumocytes and alveolar macrophages respectively. The main B[l]A adduct observed in the liver cells was not found in the lung cells. On the other hand, the levels of B[j]A adducts in the lung cells were in the range 4-14% of that found in liver cells, and no major differences between the various lung cells were observed. Neither B[l]A nor B[j]A induced DNA damage measured by alkaline elution in the lung cells, indicating that these adducts are not alkali labile.

Animals↗
PubMed1993

Impact of interferon alpha-induced cytogenetic improvement on survival in chronic myelogenous leukaemia.

The objective of this study was to investigate the prognostic impact of the reduction of Philadelphia chromosome (Ph) positive metaphases by treatment of chronic myelogenous leukaemia (CML) with interferon (IFN) alpha. Therefore, we evaluated the outcome of patients with previously untreated chronic phase Ph-positive CML, enrolled from 1984 to 1990 into two consecutive IFN trials at our institution. Of a total of 71 patients, 62 (87%) were evaluable for cytogenetic response. No cytogenetic improvement was seen in 16 patients (23%), 28 patients (38%) had a decrease in Ph-positive bone marrow metaphases to levels ranging from 35% to 95%, and nine patients (13%) to levels between 5% and 34%. In nine patients (13%), Ph-positive metaphases were no longer detectable. After a median follow-up period of 33 months, the projected 5-year survival is 55% for the 62 patients evaluable for cytogenetic response. In this patient population there was no significant difference in the survival probability according to patients' risk status as defined by the Sokal score. Categorization according to the extent of Ph reduction, however, allowed three groups with significantly different prognoses to be identified. Patients achieving a Ph reduction to less than 35% were found to constitute a low risk group with a median survival not yet known and a projected 5-year survival of 90%. The 5-year survival rate was 55% for patients with a Ph reduction to levels between 35% and 95%, and less than 10% for those without any cytogenetic improvement. Thus, this study demonstrates that cytogenetic improvement on IFN treatment is an important prognostic factor for survival.

Adolescent↗
PubMed1993

Long-term treatment of chronic myelogenous leukemia with different interferons: results from three studies.

131 patients with Philadelphia (Ph') chromosome positive chronic myelogenous leukemia (CML) were treated with interferon (IFN) alpha or a combination of IFN alpha and IFN gamma. In study, 1, 13 not pretreated and 41 pretreated patients, 48 in chronic phase disease, 6 in accelerated phase, received 4 x 10(6) U/m2 IFN alfa-2b initially. After achievement of hematologic remission, the individually minimum effective dose was used for maintenance. There was no response in acute phase disease. Of the 48 patients with chronic phase disease, 22 achieved a hematologic remission (HR), 13 a partial HR (PHR), and 13 did not respond (NR) to IFN. No major cytogenetic response occurred in these patients, but two patients achieved a major molecular response in Southern blots, whereas PCR tests were positive. In a further randomized study, CML patients without prior therapy were treated initially with 4 x 10(6) U/m2 IFN alpha alone (arm A) or in combination with 50 micrograms IFN gamma (arm B). For maintenance, the maximum tolerable dose of IFN alpha was given (up to 10 x 10(6) U/day). Thirteen patients in arm A (54%) and 14 (56%) patients in arm B achieved a HR, 7 patients (29%) in arm A and 6 patients (24%) in arm B a PHR. No response could be induced in 4 patients (17%) of arm A and 5 patients (21%) of arm B. Major cytogenetic responses were observed in 5 (20%) patients of arm A and 5 patients (20%) of arm B. Major molecular responses were observed in 3 patients of arm A and 5 patients of arm B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Hexadecylphosphocholine may produce reversible functional defects of the retinal pigment epithelium.

Hexadecylphosphocholine is a synthetic phospholipid derivative that has antitumor activity due to its interference with membrane functions. Animal experiments have shown photoreceptor and retinal pigment epithelium (RPE) degeneration after its systemic application. In a phase II trial of hexadecylphosphocholine therapy in 23 patients with advanced metastatic colorectal or lung cancer, visual acuity and color vision testing, slit-lamp examination, tonometry, fundoscopy (including photodocumentation), visual field testing, electrooculography (EOG), and electroretinography (ERG) were performed. A baseline examination was carried out prior to therapy. Patients were reexamined after 2 months and after 5 months. In all, 71% of the patients had a reduced light peak in the EOG during therapy. After the end of therapy the light peak improved again and became normal in most patients. The statistical analysis showed that the light-peak values during therapy were significantly lower than the baseline and posttreatment values. This indicates that hexadecylphosphocholine might be capable of producing a partly reversible functional defect of the RPE. Apart from this finding, no other functional or morphological ocular side effect was detected. The functional changes observed in our patients as well as the morphological changes found in animal experiments are similar to those reported for known diseases of the RPE-photoreceptor complex. Therefore, hexadecylphosphocholine-induced retinopathy might become useful as an animal model for such diseases.

Adenocarcinoma↗
PubMed1992

[Refractory anemia with 5q--anomaly. Clinical picture and follow-up of seven patients].

The clinical picture and the course of the disease of seven patients with the 5q-syndrome are described. Examination of peripheral blood revealed refractory anaemia with macrocytosis, anisocytosis, poikilocytosis of erythrocytes, and platelet anisocytosis with some giant platelets. Characteristic bone marrow findings are megaloblastic dyserythropoiesis and micromegakaryocytes with hypolobulated nuclei. Cytogenetically, an interstitial deletion of the long arm of chromosome 5 is always found, associated with a haploid loss of the genes for the growth factors GM-CSF, M-CSF and IL-3. The disease is usually chronic, and only in the case of clonal evolution is there a considerable risk of leukemic transformation occurring. In the chronic phase, infusion of packed red cells as required individually has proved a reliable form of treatment. The results of chemotherapy have disappointed both in the chronic and acute phases of the disease.

Adult↗
PubMed1992

Metaphase and interphase cytogenetics with Alu-PCR-amplified yeast artificial chromosome clones containing the BCR gene and the protooncogenes c-raf-1, c-fms, and c-erbB-2.

A human yeast artificial chromosome (YAC) library was screened by polymerase chain reaction with oligonucleotide primers defined for DNA sequences of the BCR gene and the protooncogenes c-raf-1, c-fms, and c-erbB-2. Alu-PCR-generated human DNA sequences were obtained from the respective YAC clones and used for fluorescence in situ hybridization experiments under suppression conditions. After chromosomal in situ suppression hybridization to GTG-banded human prometaphase chromosomes, seven of nine initially isolated YAC clones yielded strong signals exclusively in the chromosome bands containing the respective genes. Two clones yielded additional signals on other chromosomes and were excluded from further tests. The band-specific YACs were successfully applied to visualize specific structural chromosome aberrations in peripheral blood cells from patients with myelodysplasia exhibiting del(5)(q13q34), chronic myeloid leukemia and acute lymphocytic leukemia with t(9;22)(q34;q11), acute promyelocytic leukemia (M3) with t(15;17)(q22;q21), and in a cell line established from a proband with the constitutional translocation t(3;8)(p14.2;q24). In addition to the analysis of metaphase spreads, we demonstrate the particular usefulness of these YAC clones in combination with whole chromosome painting to analyze specific chromosome aberrations directly in the interphase nucleus.

Base Sequence↗
PubMed1992

Loss of chromosome 3 alleles and multiplication of chromosome 8 alleles in uveal melanoma.

Uveal melanoma is the most frequent primary intraocular tumor. The etiology is unknown. Using neutral DNA polymorphisms on chromosomes 2, 3, and 8, we have detected loss of chromosome 3 alleles in 8 of 13 tumors and multiplication of chromosome 8 alleles in 6 of 11 tumors. No anomalies at a locus on chromosome 2 were found in 10 of 10 tumors. These results confirm and extend previous cytogenetic findings and suggest that a tumor suppressor gene on chromosome 3 and an oncogene on chromosome 8 may be involved in the formation or progression of this tumor.

Adult↗
PubMed1992

Transvaginal intra-abdominal impalement injury.

Impalement injuries due to sexual activity are highly unusual and variable. We have described a case of transvaginal impalement injury of the rectum, bladder, omentum, and mesentery manifested by vaginal bleeding. The patient could not recount how she had been injured. Management of such an injury requires extensive initial evaluation and a multidisciplinary approach to therapy.

Abdominal Injuries↗
PubMed1992

Combination therapy with interferon alpha-2b plus low-dose interferon gamma in pretreated patients with Ph-positive chronic myelogenous leukaemia.

Between March 1988 and July 1990, 28 adults with chronic myelogenous leukaemia (CML) were treated with a combination of recombinant human interferon (IFN) alpha-2b s.c. (initial dose 4 x 10(6) U/m2) and recombinant human IFN gamma s.c. (50 micrograms totally) daily. All patients were in chronic phase disease and had been treated previously with chemotherapy or bone marrow transplantation. A complete haematologic remission was achieved in three patients (11%), a haematologic remission in 12 patients (43%), and a partial haematologic remission in seven patients (25%). Six patients did not respond to this schedule. Acute side-effects were flu-like symptoms, fever and chills. During long-term treatment six patients developed polyarthralgia. Haematotoxicity WHO grade III occurred in three patients, and WHO grade IV in two patients. One patient developed psychosis, and in another patient an exacerbation of a pre-existing sarcoidosis was observed. We conclude that this combination is tolerable and effective in inducing haematological remissions in pretreated CML patients.

Adolescent↗
PubMed1992

A prospective randomized comparison of single-agent interferon (IFN)-alpha with the combination of IFN-alpha and low-dose IFN-gamma in chronic myelogenous leukaemia.

In patients with previously untreated chronic myelogenous leukaemia (CML) the efficacy of single-agent interferon (IFN)-alpha at an initial dose of 4 x 10(6) U/m2 (arm A) was compared with the combined administration of the identical dose IFN-alpha plus a total dose of 50 micrograms IFN-gamma (arm B). 51 patients entered this study between April 1987 and October 1989; the analysis was performed in March 1991 and was focused on response rates and toxicity. 54% of patients on arm A and 56% of arm B patients attained haematologic remission. 29% of patients on arm A and 24% of arm B patients had partial haematologic remission. A decrease in Philadelphia chromosome (Ph)-positive metaphases of more than 10% was only seen in patients who had achieved complete haematologic normalization. In 21% of patients on arm A and 20% of arm B patients, the percentage of Ph-positive cells declined to less than 35%. Toxicity was different between the two study groups with more pronounced hepatotoxicity observed in patients treated with IFN-alpha alone. Among the patients receiving both IFNs, alpha and gamma, there were 2 fatal infectious complications. This serious toxicity in conjunction with lack of a clinically meaningful difference between the two treatment schedules has led us to terminate the study. In conclusion, the addition of low-dose IFN-gamma failed to improve the efficacy of IFN-alpha in this study.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Minimal residual disease in patients with chronic myelogenous leukemia undergoing long-term treatment with recombinant interferon alpha-2b alone or in combination with interferon gamma.

Interferon (IFN) therapy has become widely used for the treatment of chronic myelogenous leukemia. Hematologic remissions can be induced in about 60% of patients. Moreover, in a small number of patients loss of the Philadelphia (Ph) chromosome and of the BCR-ABL rearrangement is observed. We have used genomic Southern blotting as well as a two-step polymerase chain reaction (PCR) method to score for BCR-ABL messenger RNA (mRNA) in patients with hematologic remission induced by treatment with IFN alpha-2b alone or in combination with IFN gamma. Concomitantly, cytogenetic analysis was performed. In 11 of 115 patients reported here, a complete loss of rearranged BCR fragments was observed in Southern blots of peripheral blood (PB) and/or bone marrow (BM) cell samples. Malignant marker bands disappeared first in the PB. In six patients, this genotype remained stable, whereas in five patients, low-intensity, rearranged bands reappeared despite continuation of treatment. The reappearance of the malignant marker was not accompanied by a clinical relapse. Ph-negative metaphases were observed in PB cells of four patients and in the PB and BM cells of two of these patients. In the samples of the other patients, residual Ph-positive cells were detected. By two-step PCR, residual BCR-ABL rearranged transcripts were found in samples of 10 patients.

Adult↗
PubMed1991

High-dose 1,2,4-triglycidylurazol given in regimens preparatory to bone marrow transplantation. A preclinical pharmacology study.

To elucidate its potential role in the framework of bone marrow transplantation, we studied the toxicologic and pharmacologic properties of high doses of the triepoxide derivate 1,2,4-triglycidylurazol (TGU) in a preclinical dog model. Dose-dependent and dose-limiting gastrointestinal toxicity occurred in a dose range between 40 and 75 mg/kg, with the lethal dose for 50% of animals (LD50) being estimated at 60 mg/kg. Severe and life-threatening hematologic toxicity developed at all dose levels examined but was generally reversible. The combination of TGU and total-body irradiation produced synergistic gastrointestinal toxicity, necessitating reductions of the TGU dose by 50% as compared with the single-agent dose. In contrast, the combination of TGU and high-dose busulfan resulted in no apparent nonhematologic synergistic toxicities. The immunosuppressive properties of TGU given in this combination enabled sustained histocompatible allogeneic marrow engraftment in three of four animals. The pharmacokinetics of TGU were not influenced by prior total-body irradiation or high-dose busulfan. We conclude that the myelotoxic, pharmacologic and immunosuppressive properties of high-dose TGU observed in this preclinical model seem to render the drug particularly suitable for use in regimens preparatory to bone marrow transplantation.

Animals↗