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Biomedical subjects

M Bamberg

Publications and source records attributed to M Bamberg.

At least 163 records · Page 9Linked to original sources
PubMed1992

[Diagnosis and therapy of meningosis neoplastica].

Metastatic leptomeningeal disease occurs in 5-30% of patients with breast or lung cancer, malignant melanoma, non-Hodgkin's lymphoma, leukemia and primary malignant brain tumors. Intrathecal chemotherapy with methotrexate, cytarabine, or thiotepa combined with irradiation of the site of major involvement increases overall median survival from 1-2 months to 2-7 months. Clinical outcome is limited by progression of systemic or CNS disease and by the neurotoxic side effects of therapy, i.e. leukoencephalopathy. New immunotherapeutic strategies of intrathecal treatment may be effective and less toxic, but are not yet sufficiently defined and available. This review covers the current diagnostic and therapeutic features of metastatic leptomeningeal disease. Pragmatic therapeutic recommendations, based on available clinical knowledge are given with special consideration of the side effects of therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Photoimmunotherapy of human ovarian carcinoma cells ex vivo.

Photodynamic therapy is a relatively new and potentially selective experimental approach to the treatment of malignant neoplasms. Its inherent dual selectivity is reinforced by the use of photosensitizer-monoclonal antibody conjugates. The goal of this study was to evaluate the phototoxicity and selectivity of an immunoconjugate (IC) synthesized from a chlorin derivative chlorin e6-monoethylenediamine monoamide (CMA) as the photosensitizer and an anti-ovarian carcinoma monoclonal antibody OC125. Binding efficiency and specificity of the IC were determined by enzyme-linked immunosorbent assay, and specific covalent linkage of the monoclonal antibody to the photosensitizer was demonstrated by fluorescence and electrophoresis. Phototoxicity was tested against ascites or pleural fluid cells from 15 patients with ovarian and nonovarian cancers. Tumor cells from the fluid were treated with the IC at 3 microM equivalent CMA concentration and irradiated at 654 nm (lambda max CMA in IC) at 25 J/cm2 from an argon ion-pumped dye laser. Phototoxic efficacy was assayed by [3H]thymidine incorporation. Ovarian cancer cells exhibited high cytotoxicity with [3H]thymidine incorporation of 2.4 +/- 2.2%, while nonovarian cancer cells under identical conditions exhibited none to reduced cytotoxicity with [3H]thymidine incorporation of 70 +/- 54%. Using a Wilcoxon test, there was a statistically significant difference between these two groups (P less than 0.001). Dose-response curves revealed reciprocity in photosensitizer concentration and fluence. These results demonstrate that photoimmunoconjugates retain significant antigen binding specificity and affinity, are effective in the selective photochemical eradication of target cells, and merit further evaluation as photochemotherapeutic agents.

Antibodies, Monoclonal↗
PubMed1991

On the ability to provide evaluative comments: further explorations of children's narrative competencies.

This study investigated the changing functions of evaluative devices in children's narratives. The evaluative devices included (a) references to 'frames of mind', particularly to emotions, (b) character speech, (c) 'hedges', (d) negative qualifiers, and (e) causal connectors. Narratives were elicited from a 24-picture story book. The subjects were three groups of native English-speaking Americans (12 per group): five- and nine-year-old children and college undergraduate students. A quantitative comparison revealed that (i) adults used evaluative devices three times as often as five-year-olds, and two-and-a-half times as often as the nine-year-old children; (ii) adults used significantly more references to 'frames of mind' and 'hedges' than the children; and (iii) whereas five-year-olds used each evaluative type equally often, nine-year-olds and adults used references to 'frames of mind' significantly more than the other four evaluation types. A second analysis, focusing specifically on the discourse functions of references to 'frames of mind' revealed that, early on, this particular device is used to express a local evaluative perspective on particular events, while with increasing age it is used to signal the hierarchial organization of the story events. These findings are discussed with regard to two non-linguistic developmental achievements, the formation of event schemas and the formation of a theory of mind.

Adult↗
PubMed1991

[The value of NMR tomography in the planning of HDR-afterloading brachytherapy in cervical carcinomas. The experiences with 41 patients].

In 41 patients with inoperable cervical carcinomas, afterloading brachytherapy was used in combination with radiotherapy after planning with MRI (1.5 T spin echo multislice technique). In 27 women, phantoms neutral to MRI were introduced into the uterus to create a topographic situation comparable to that during brachytherapy; at the same time, the position of the applicators was marked. Under the circumstances, MRI demonstrated the position of the uterus and the tumour, the vagina, the bladder, the rectosigmoid and the applicator phantoms in every case. In 88% it was possible to demonstrate the margin of the tumour and normal myometrium. In 18% of the patients, the technique lead to a significant and, in a further 30%, to a marginal improvement in brachytherapy technique.

Brachytherapy↗
PubMed1990

Treatment planning for neutron therapy of high-grade astrocytomas and pencil gliomas.

If astrocytomas of grade III and IV and pencil gliomas of the spinal cord would be good indications for neutron therapy, high accuracy and homogeneity of the target absorbed dose and the planned spatial dose distribution would be pre-conditions for acceptable low complication rates. Therefore, results of treatment planning calculations have been compared with in vivo measurements and found to be in good agreement. Special care is necessary if the percentage of the gamma-ray component is spatially varying and additionally for fixation of the patient and combination of radiation fields in the case of pencil gliomas. Examples are given how to avoid overdosage and to hold the inhomogeneity even at the borderline of adjacent fields within 10%.

Brain Neoplasms↗
PubMed1990

Clinical results and the Essen concept of TBI.

Total body irradiation (TBI) prior to bone marrow transplantation (BMT) is applied for treatment of 230 patients in the period 1975-1988. The clinical results of 169 patients treated by four different TBI dosage and treatment techniques are analysed. The risk of leukemic relapse is low after fractionated TBI (9%) as well as after single dose TBI (14%). The lowest frequency of interstitial pneumonitis (21%) occurred when the patient translation technique was used for fractionated homogeneous pa/ap TBI with 10 Gy (8 Gy lung dose) in 4 fractions in 4 days. Prophylaxis of GVHD and the modus of protective environment were two other factors which influence the risk of IP.

Adult↗
PubMed1990

[Adjuvant radiotherapy of rectal cancer].

Evaluation and refinement of surgical techniques in rectal carcinoma have reduced the rate of local recurrences. Nevertheless recurrence it remains high at more than 20% in patients with extensive infiltration of perirectal tissues and cures are an exception. Overview of many years of experience with adjuvant radiotherapy shows that local recurrence rate can be reduced and survival the rate improved.

Combined Modality Therapy↗
PubMed1990

Neutron boost irradiation of soft tissue and chondrosarcomas at the West German Tumour Centre in Essen.

In this retrospective study, the results of postoperative neutron boost therapy for 40 soft tissue- and 18 chondrosarcomas are presented. In 65.5% and 34.5% of all cases, microscopic to macroscopic tumour residual was left postoperatively. Locally advanced and moderate to highly malignant tumours were found at surgery in 81% and 69%, respectively. Except for seven patients with a whole series of neutrons to 16 Gy, the other cases were treated with initially 40 to 50 Gy photons and a subsequent neutron boost of 4 to 6 Gy. The median follow-up was 29.3 and 36.2 months for the soft tissue- and chondrosarcomas. The actuarial three-year local control and overall survival rates were 69.3% and 91% for soft tissue- vs. 55.6% and 62.9% for chondrosarcomas. With regard to the extension of surgery (microscopic or macroscopic residual), local control rates of 80% and 60% for soft tissue- vs. 62.5% and 40% for chondrosarcomas were observed. The overall local failure rate was 32.8% with a median disease-free interval of ten respectively eleven months for soft tissue and chondrosarcomas. 17 out of 19 local recurrences were due to inadequate irradiation portals for the neutron boost or to insufficient total doses in the initially treated photon target volume.

Actuarial Analysis↗
PubMed1990

Methods for analysis of censored tumor growth delay data.

Growth delay times of experimental tumors after subcurative therapy may be censored because of intercurrent death of the host animals, limitations of the follow-up period, or the number of cured tumors. Under the general assumptions of log-normally distributed data and independence of the censoring event and the therapy effect, it is shown using computer simulations that the estimate of the median growth delay according to the product limit method of Kaplan and Meier, which allows inclusion of censored data, is unbiased. Omission of censored growth delay times from incomplete accrued data often leads to biased estimates. The power of statistical tests for qualitative comparison of two therapy groups with incomplete sets of data from growth assays was also studied. In the absence of censoring, the power of the different tests is about the same. At higher censoring rates of 40%, however, tests applicable to censored data (log-rank test, Gehan-Wilcoxon test) have a markedly higher power than tests applied to the reduced set of complete observed growth delays (mu test, t test). Although complete observation of tumor regrowth should be strived for, growth delay experiments with very delicate animal tumor models can easily result in censored data. The methods presented permit quantitative and qualitative analysis of growth delay data up to a censoring rate of over 30%, if growth delays and censoring events are independent.

Animals↗
PubMed1989

[Dysgerminomas. Clinical aspects, therapy and prognosis with reference to the cooperative therapy study MAIKEI 83/86 for non-testicular germ cell tumors of the Society of Pediatric Oncology].

In comparison to other malignant germ cell tumors, dysgerminomas of the ovary show a high sensitivity to radiotherapy. According to histology and biological behaviour, dysgerminomas of the ovary are similar to testicular seminomas, which seem to be very sensitive to chemotherapy. Therefore, in the protocol for non-testicular germ cell tumors of the German Society of Pediatric Oncology (GPO) a treatment for dysgerminomas is established, in which the indication for primary tumor resection and a supplementary radiotherapy, or, in selected cases, primary chemotherapy and delayed tumor resection after the spreading, has been graded. After a median follow-up of 26 months, 17 of 18 patients were alive and disease-free, from which 3 patients with tumor progression after initial ovariectomy are in the second remission phase following relapse therapy. One patient died of tumor progression despite combined chemotherapy and irradiation. With a stratified therapy regime, fertility could be preserved with high probability in 13 of 17 patients.

Adolescent↗
PubMed1989

Neutron therapy of low grade "pencil" gliomas of the spinal cord: a review of ten cases.

Between 1980 and 1986 ten patients (two males, eight females, median age: 35 years) with spongioblastomas and ependymomas grade I of the spinal cord were treated with fast neutrons from the d(14) + Be reaction after incomplete tumour surgery. Eight patients received three weekly fractions of 0.7 to 1.33 Gy and two patients four weekly fractions of 0.8 Gy to total doses of 7.4 to 10.4 Gy. Two complete and six partial remissions of ataxia and motor disturbances were observed. Bladder dysfunctions in five patients cleared up partially in three cases. In two patients the symptomatology remained unchanged. After a follow-up of eight to 88 months two initially complete and two out of six partial remission were maintained. No severe late effects of the skin have been determined. In summary it is concluded that for incompletely resected "pencil"-gliomas fast neutron therapy seems to be a feasible treatment modality.

Adult↗