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R Becher

Publications and source records attributed to R Becher.

At least 145 records · Page 8Linked to original sources
PubMed1983

Sister chromatid exchange in the centromere and centromeric area.

Central and peripheral sister chromatid exchanges (SCE) were evaluated separately in human phytohemagglutinin (PHA)-stimulated lymphocytes after culture for 72 h in 5-bromodeoxyuridine (BrdU) containing medium. At the same time, the length of chromosome No. 1 was measured in 10 metaphases per case and the mean value taken as a representative parameter for the contraction of chromosomes. The statistical analysis of regression revealed a close relationship between the percentage of SCE observed in the centromere and the contraction state of chromosomes (P less than or equal to 0.01). A statistically significant increase of central exchanges was seen in more condensed chromosomes, due to the difficulty in differentiating clearly between centric and pericentric exchanges. Consequently, if exchanges in the centromere are omitted from evaluation, this would lead to spuriously low SCE rates in more contracted chromosomes. In order to exclude the variable factor of chromosome contraction in SCE studies, we highly recommend inclusion of counts of central exchanges. Results obtained on chromosomes with twisted chromatids, a situation which tends to stimulate SCE, should be omitted.

Centromere↗
PubMed1983

Chromosome 6 in malignant melanoma.

Cytogenetic analysis of malignant melanoma (MM) cells from a number of cases revealed the frequent involvement of chromosome 6 in structural aberrations. The relevance of these findings to certain aspects of MM is briefly discussed.

Chromosome Aberrations↗
PubMed1983

Chromosomes and causation of human cancer and leukemia. LIII. Comprehensive cytogenetic analysis of an erythroleukemia.

A comprehensive cytogenetic analysis has been performed in a case of erythroleukemia (EL), M6 in the FAB classification. A bone marrow sample was shown to be characterized by an unusually high degree of polyploidy with the presence of a dominating hypotetraploid clone. G-banding analysis revealed extensive structural rearrangements involving chromosomes #1,#3,#12,#16,#17, and #21. The SCE frequency was higher in the cells of the dominant clone when compared to that of near-diploid, presumably nonmalignant cells. Cell cycle analysis revealed that the hypotetraploid cells progressed through the cell cycle much slower than did the near-diploid cells.

Aged↗
PubMed1983

Involvement of chromosomes 7 and 12 in large bowel cancer: trisomy 7 and 12q-.

Cytogenetic analysis of an adenocarcinoma of the large bowel with some villous features revealed consistent chromosome changes: trisomy of chromosomes No. 7, 12, and 20 and a deletion of part of the long arm of a chromosome No. 12. Examination of the chromosome findings in previously published cases of large bowel cancers and the data presented in this paper lead us to suggest that trisomy No. 7 and 12q- may be nonrandom (primary) karyotypic changes in a subgroup of large bowel cancers.

Adenocarcinoma↗
PubMed1983

Unusual SCD in cancer cells: a phenomenon related to decreased BrdU incorporation?

The simultaneous presence of chromosome segments with and without sister chromatid differentiation (SCD) in the same metaphase was observed in a human melanoma cell line after BrdU incorporation for 48-72 hr. This phenomenon was related to the time of BrdU incorporation by the cells: i.e., it was not observed after exposure to BrdU for only 17-20 hr. It is proposed, therefore, that the unusual staining pattern is caused through reduced BrdU incorporation by the cells after completing the first division.

Bromodeoxyuridine↗
PubMed1983

Cytogenetic testing of mutagenic and radioprotective effects of mesna.

The effects of mesna (sodium 2-mercaptoethane-sulfonate) on the frequency of sister chromatid exchange (SCE) and chromosomal aberrations were studied in PHA-stimulated lymphocytes in vitro. Our data give no evidence for either an increase of SCE or chromosomal aberrations and, thus, do not suggest a mutagenic or cancerogenic potential of this drug, when used clinically for the reduction of urotoxicity caused by oxazaphosphorine derivatives in cancer therapy. The possibility of a radioprotective effect of mesna could not be supported by the results obtained in this test system. However, there remained a slight comutagenic effect of mesna, if used together with irradiation, which should be taken into account when this drug is administered in the preparation of patients for bone marrow transplantation.

Chromosome Aberrations↗
PubMed1983

Sister chromatid exchange and proliferation pattern after ultrasound exposure in vivo.

The sister chromatid exchange (SCE) frequency and cell-cycle specific metaphase patterns were investigated in PHA-stimulated lymphocytes in vitro after in vivo exposure of 15 patients to diagnostic ultrasound. No significant differences were found in SCE rates before and after ultrasound exposure. The evaluation of cell-cycle specific metaphase patterns, differentiating cells which passed one, two, or more cell cycles, gave no evidence for a cell-growth inhibitory effect. Since SCE is regarded as a highly sensitive method for the detection of mutagenic effects, our data confirm previous reports on the genetic safety of diagnostic ultrasound.

Adolescent↗
PubMed1983

Nonrandom chromosome changes in malignant melanoma.

Chromosome aberrations were analyzed in 4 cases of malignant melanoma (MM) after disaggregation of the tumors with collagenase and short-term culture. In all cell cultures, the MM cells displayed a typical triangular spindle form. The chromosome number was near-diploid in one case and near-triploid in three cases. A total of 27 abnormal chromosomes were identified with the Giemsa banding technique. By far, the most common types of abnormalities were translocations, followed by deletions and isochromosomes. Chromosomes 1, 6, and 7 were found to be most frequently involved in structural aberrations. Markers originating from chromosomes 1 and 6 were found in all four cases, and abnormalities of chromosome 7 were found in three. Each marker chromosome was unique for a given case; no common markers for two or more cases were found. Based on the present results and an analysis of reports on the chromosomal constitution of MM cells in the literature, we suggest that abnormalities involving chromosomes 6 and 7 may be a characteristic feature of MM. Aberrations of chromosome 1, although common in MM, may be part of a general cytogenetic feature in human neoplasia.

Adult↗
PubMed1982

Sister chromatid differentiation and cell-cycle-specific patterns in chronic myelocytic leukemia and normal bone marrow.

After in vitro incubation with bromodeoxyuridine (BrdUrd)-containing medium, metaphases of Philadelphia (Ph1)-chromosome positive cells in the blood and/or bone marrow of eight untreated patients with chronic myelocytic leukemia (CML) were analysed by means of sister chromatid differentiation (SCD) and compared to 10 normal bone marrows. The majority of proliferating Ph1-positive cells (range: 46-86%) were unable to complete more than one cell cycle during the culture period of 50 h (MI metaphases). Ph1-positive M2 metaphases which had completed two cell cycles were found in the range of 18-54% and almost no M3 metaphases were detected after passage through three cell cycles (0-1%). The corresponding findings in proliferating normal bone-marrow cells were: MI (13-68%), M2 (30-79%) and M3 (0-18%). These data support the notion that there is a prolonged cell cycle time in CML which can be measured by SCD, demonstrating a proportional shift from M3/M2 to MI metaphases. SCD is suggested for kinetic studies on human malignant cell clones characterized by marker chromosomes.

Adolescent↗
PubMed1982

A randomized study of combination chemotherapy (VAC-FMC) with or without immunostimulation by Corynebacterium parvum in metastatic breast cancer.

A total of 156 patients with metastatic breast cancer were entered into a prospective multi-center trial in September 1975. All patients were treated monthly with vincristine, adriamycin and cyclophosphamide (VAC) six times, followed by 5-fluorouracil, methotrexate and cyclophosphamide (FMC) until progression was documented. By random assignment, the patients received 5 mg/m2 Corynebacterium parvum (CP) subcutaneously on day 1, in addition to VAC/FMC. Of the 150 evaluable patients, 33 of 76 (45%) and 36 of 74 (49%) had complete or partial response to VAC/FMC plus CP, respectively. The Kaplan-Maier curves of duration of remission and survival were almost identical (medians 14.5 vs 12.1 months and 22.2 vs 21.1 months, respectively). The hematologic and gastrointestinal toxicity were also similar in the two study groups. However, 19 of 74 (26%) patients developed skin ulcers after repeated injections of CP. These patients showed prolonged survival (P = 0.002, log rank test). These results suggest that adding nonspecific immunostimulation with CP to currently available chemotherapy on day 1 is of no benefit to most patients with metastatic breast cancer, but may select an "immunoreactive subgroup with increased local toxicity and survival.

Adjuvants, Immunologic↗
PubMed1982

[Bone marrow transplantation for aplastic anaemia and acute leukaemia (author's transl)].

Twenty-six bone marrow transplantations were performed at the West Germany Tumour Centre at Essen between December 1975 and December 1981. Three patients had aplastic anaemia, 23 acute leukaemia. Of the leukaemia patients 13 had a recurrence and ten were in full remission at the time of the transplantation. Two of the patients with a recurrence received deep-frozen autologous marrow from the remission phase. One patient with aplastic anaemia had an identical twin as donour, while all other patients received allogeneic marrow from histocompatible family members. Eleven patients are still alive, all three of those with aplastic anaemia, one of those with leukaemia in a recurrence, and seven of those with acute leukaemia in full remission. Two of the survivors have a chronic graft-host reaction, but the others are symptom-free, after an observation period of up to four years. Main causes of death were leukemic recurrence (6), infection (5), and graft-host reaction (2). It would seem that at present bone marrow transplantation offers the best chance of a cure for severe aplastic anaemic and acute leukaemia in adults, but only if transplantation is undertaken early and not in the end-stage of the disease.

Acute Disease↗
PubMed1982

Post-rest adaptation of electrical and mechanical activity in the isolated guinea-pig papillary muscle.

In guinea-pig papillary muscle the time course of the changes in contractile force and action potential duration (APD) were studied after periods of rest of variable duration. After a long period of rest, the force of contraction adapted to pre-rest control values in a monophasic manner whereas the time-course of the APD was clearly biphasic. The post-rest adaptation of the APD could be described mathematically by a simple model, which considers the action potential duration during steady state as the sum of a resting value (APDR) plus a lengthening effect of activation (LEA) minus a shortening effect of activation (SEA). LEA and SEA are assumed to occur immediately, with each excitation and to decay continuously. During repetitive stimulation, both effects will accumulate. Using the constants found for the post-rest adaptation of the APD, the steady-state frequency-dependence of the APD could also be described with this model.

Action Potentials↗
PubMed1982

[The present state of the art in diagnosis and therapy of cancer of the breast (author's transl)].

Opinions regarding the best possible treatment of cancer of the breast are more controversial than ever. This article analyses the present state of the art in diagnosis of the carcinoma of the breast on the basis of an extensive review of published literature. The methods are evaluated with regard to their value in early recognition and mass screening. The pros and cons brought forward in the discussion on the optimum treatment of this kind of tumour are described. Since no final judgment can be passed at the present moment, an attempt is made to explain the present state of therapy according to stages as seen from the radiologist's point of view.

Adult↗
PubMed1981

Sister chromatid exchange and growth kinetics in untreated acute leukemia.

Sister chromatid exchange (SCE) frequency has been analyses after short-term culture of leukemic bone marrow cells of eight untreated patients with acute leukemia. Compared to normal bone marrow, results show a statistically significant decrease of SCE (p less than 0.001) in euploid as well as in aneuploid leukemias, ranging from 2.11 to 2.97 SCE per metaphase. The different SCE values were not related to contraction status of chromosomes and could not be explained by the age of patients. Therefore, low SCE may be a typical feature of leukemic cells. An examination of growth rates by the SCE technique revealed a high turnover of normal bone marrow cells. About 80% of the cells did not need more than 50 h to run two or three cell cycles. Leukemic cells, however, apparently divided more slowly, which is in good agreement with data obtained by autoradiographic methods.

Acute Disease↗
PubMed1981

[High-dosed gestagen therapy of the metastatic mammary carcinoma (author's transl)].

Thirty patients with histologically proven metastatic mammary carcinoma were treated, after exhaustion of hormonal and cytostatic therapeutic means, with high-dosed medroxyprogesterone acetate (MPA) during a ten-day induction phase with 1000 mg MPAi.m. per day and then with 600 mg oral MPA per day. In eleven patients a complete or partial remission was achieved. The median period of remission comprised ten months. A positive relationship was found between the response to high-dosed MPA therapy and the length of free intervals. Side effects were tolerable.

Adult↗