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Biomedical subjects

W Göhde

Publications and source records attributed to W Göhde.

At least 55 records · Page 3Linked to original sources
PubMed1986

Flow cytometry as a tool for the prognostic assessment of human neoplasia.

Flow cytometry permits the quantitative description of neoplastic cell populations from the point of view of their cytogenetic and cytokinetic features. The advances in preparation of cellular monodispersed samples allow the examination not only of in vitro and hematological, but also of surgical, biopsy, endoscopic, and lavage specimens. The analysis of cytometric DNA content has evidenced the importance of (aneu)ploidy as a remarkable tumor marker. Tumors of different sites and, in some cases, stages and/or grades are characterized by a differential occurrence of diploid vs. aneuploid cell subpopulations and by the eventual presence of different stem cell lines within the same tumor. For certain classes of neoplasms, these parameters can be used for the early recognition of neoplasia and related to disease evolution and dissemination and to the results of therapy. Flow cytometry can also be used to evaluate the fraction of (cycling) cells in the S-phase and of proliferating cells (growth fraction). The percent of S cells can be extracted from cytometric DNA content histograms. Furthermore, the method of Bromodeoxyuridine (BrdUrd) incorporation has been recently introduced into flow cytometry. BrdUrd labeling in cycling cells can be detected either by the induction of quenching or enhancement of specific DNA-dye fluorescence or by fluorescent anti-BrdUrd monoclonal antibodies. This approach has been confirmed by preliminary comparative tests on cultured cells, normal and malignant bone marrow, and human solid tumor specimens. These parameters, together with other cytometric parameters of potential importance for the cellular characterization of malignancy, offer a reliable and real time-saving tool for the prognostic assessment of human tumors and the predicting and monitoring of the results of therapy.

Aneuploidy↗
PubMed1986

Effect of doxorubicin and 4'-epi-doxorubicin on mouse spermatogenesis.

Flow cytometric and histological analysis, measurements of testicular weight and sperm head counts were performed to analyze the effects of doxorubicin (DX) and 4'-epi-doxorubicin (4'-epi-DX), two closely related antineoplastic agents, on mouse spermatogenesis. The DNA distribution patterns obtained by flow cytometry indicate the frequency of different germ cell types: elongated and round spermatids, primary spermatocytes with a 4 c DNA content, and S-phase spermatogonia and spermatocytes. Following the injection of different doses of DX, characteristic changes of the frequencies of those germ cell types are observed with time, indicating selective inactivation of spermatogonia followed by sequential depletion of spermatocytes, round spermatids and elongated spermatids, and then recovery of these cell types. Similar changes were observed with 4'-epi-DX; the dose-response curves indicated that 4'-epi-DX might be slightly, although not significantly, less effective than DX. The mutagenic potential of DX and 4'-epi-DX is reflected by an increase of the coefficient of variation in the DNA histogram as a measure of aneuploidy, and an increase of diploid spermatids. Flow cytometric analysis of spermatogenesis offers a sensitive in vivo system to monitor mutagenic agents.

Animals↗
PubMed1986

Considerations in the design of possible cell cycle effective drugs.

Antineoplastic agents are known to induce differential cytotoxic and cytostatic effects throughout the cell cycle. Many drugs have greater toxicity for cycling cells and act selectively at one or more phases of the cycle and may cause partial synchrony of surviving cells. However, these observations have been generally carried out on in vitro systems only and present a variety of complexities and pitfalls. Furthermore, human tumours are often characterized by a relatively low fraction of proliferating cells and present a large cellular heterogeneity as far as their cytogenetic, cytokinetic, and clonogenic features and their responses to drugs are concerned. Therefore, resistance to chemotherapy is due to various factors characterizing, in some instances, each individual tumour. In spite of the advent of technological advances such as flow cytometry, it is still difficult to design kinetic-orientated therapies especially for the treatment of solid tumours. Consequently, it is also difficult to design protocols based on cell cycle effective drugs. The possibility remains, at least for the moment, to stratify tumours according to their cellular heterogeneity. Different protocols could then be assigned to classes of tumours. Such an approach could be completed by further advances in the cellular monitoring of individual tumours.

Alkylating Agents↗
PubMed1986

Frequency and clinical significance of DNA aneuploidy in acute leukemia.

Analyses of the cellular DNA content were carried out in 446 patients with newly diagnosed acute myeloid (AML) and lymphoblastic (ALL) leukemias in order to assess the frequency of DNA aneuploidies and its relation to immunologic and morphologic subtypes as well as its prognostic relevance. Based on high resolution FCM analyses and standardized reference measurements, DNA aneuploidies were identified at a similar frequency in children and adults with AML (38.0% and 40.0%) and ALL (40.0% and 37.4%). In AML aneuploid DNA stemlines were significantly less frequent in FAB-M 1 cases as compared to the other morphologic subtypes (p less than 0.05), whereas the degree of DNA aneuploidy was significantly lower in M 1 and M 2 leukemias as compared to the M 4 and M 5 subgroups (p less than 0.05). In ALL non-T/non-B and C-ALL revealed a higher frequency of DNA aneuploidies than T- and Null-ALL cases (p less than 0.05). No differences in the response to induction therapy were found between patients with and without DNA aneuploidy in children or adults with AML or ALL. In the childhood ALL trial BFM 79/81, however, a significantly higher frequency of long term remissions was observed in children with DNA aneuploidy (0.91 versus 0.66 at five years, p = 0.053). A similar though not significant tendency was also revealed from the AML studies BFM 78 in children and 78/81 in adults. In the subsequent studies these differences could not be confirmed at present, possibly because of the considerably shorter observation time.

Adult↗
PubMed1986

[Studies of the cell kinetics of human malignant testicular tumors].

The cellular DNA-content of 75 malignant testicular germ-cell tumours was determined by flow cytometry. The results are: Aneuploidy is a certain tumour marker in 95% of germ-cell tumours. The DNA-indices range from 2 c (diploid) to 6 c with a modal value around 3 c. 23% of germ-cell tumours are multiclonal. The S-phase percentage is higher than those of the most other solid tumours investigated so far and is 25.5% in seminomas and 35% in non-seminomatous germ-cell tumours. Further investigations of a greater number of tissues will show the importance of DNA-contents measurement by flow cytometry for the prognosis of testicular tumours, representing an addition to histopathology.

Aneuploidy↗
PubMed1985

Differential pattern of DNA-aneuploidy in human malignancies.

The differential pattern of DNA-aneuploidy, detected by flow cytometry (FCM) regarding its frequency, grade and multiclonality, was investigated and correlated to tumor type, malignancy grade, tumor stage and prognosis in a multi-institutional study at the University of Münster. High resolution measurements using admixed normal blood reference cells were undertaken in 2413 cases of 13 different malignant diseases and in 776 benign lesions or samples. The incidence of DNA-aneuploidy was highest in melanomas, carcinomas, testicular tumors, sarcomas (75%-95%) and myelomas (65%). Acute leukemias showed an intermediate DNA-aneuploidy rate of 40% with special subgroups represented by common ALL (44%), p less than 0.05) and myelomonocytic/monocytic AML (47%, p less than 0.01). The lowest DNA-aneuploidy-rate was found in basal cell skin carcinomas (19%) and congenital melanocytic nevi (9%). No case of DNA-aneuploidy was observed in the 776 benign lesions or samples.--DNA-indices giving the grade of DNA-aneuploidy with 1.0 for normal diploid G1/0 cells were found distributed predominantly between 1.0 and 2.0 in the solid tumors, except testicular tumors, clustering around a triploid maximum at 1.5. DNA-indices of myelomas and acute leukemias generally ranged below 1.25 with lower DNA-aneuploidy grades in AML than in ALL (p less than 0.01).--In melanomas the aneuploidy rate was higher (86%) in metastases than in the primary tumors (54%, p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Enhanced cell killing through the use of cell kinetics-directed treatment schedules for two-drug combinations in vitro.

Kinetics-directed drug treatment schedules were tested in Chinese hamster ovary cells. Ten hr after treatment with 1,2:5,6-dianhydrogalactitol (DAG) (at a dose lethal to less than 5% of the cells), a 150% enrichment of cells into the S phase of the cell cycle was observed. This blockade in S phase was reversible and was followed at 18 hr after an exposure to DAG by a 200% increase in the fraction of cells in the G2-M phases of the cell cycle. Bleomycin, known to be most effective against G2 + M cells, had the greatest effect on cell killing when administered at that time. Rapid analysis by flow microfluorometry techniques was used to determine the DAG-induced kinetics changes, thus allowing treatment with the second drugs at the most opportune time. The DAG-induced kinetics changes were also demonstrated in a line of human adenocarcinoma of the stomach in vitro and in Ehrlich ascites tumor cells in vivo. In all cases, the enrichment of cells into S phase was reversible at the doses used and was followed by a reversible blockade in G2-M.

Adenocarcinoma↗
PubMed1981

Flow cytometric measurement of nuclear DNA content variations as a potential in vivo mutagenicity test.

Mutagen-induced variations of the cellular DNA content have been studied in mouse bone marrow cells in vivo using high resolution flow cytometric techniques. During the first days after a single injection of the chemical mutagen cyclophosphamide an increased coefficient of variation in the G1 peak of the flow histograms was observed. The magnitude and duration of this effect were dose-dependent. The reproducibility of the measurements was high, indicating that individual variability between animals and instrumental dispersion is small. The results demonstrate that on the basis of the flow cytometric measurement of cellular DNA content, a short-term in vivo test for mutagenicity can be established which is much faster than conventional cytogenetic methods.

Animals↗
PubMed1981

A rapid automated stathmokinetic method for determination of in vitro cell cycle transit times.

To provide a rapid method for examining cell cycle dynamics, we utilized continuous exposure of Chinese hamster ovary cells and human colon cancer cells to colcemid to block cycling cells in metaphase, suppressing re-entry into G1. Changes in cell cycle compartment distribution were monitored by DNA flow cytometry. Analysis of the rate of G2 + M compartment accumulation after addition of colcemid permitted calculation of all cycle transit parameters. These compared favorably with data in the same cell lines determined by the fraction of labeled mitoses technique. Serial assessment of DNA flow cytometry after addition of colcemid permits rapid quantitation of cycle traverse rates.

Animals↗
PubMed1981

Mammalian spermatogenesis as a biologic dosimeter for radiation.

Mouse spermatogenesis was used as an in vivo test system obviously suitable as a biologic dosimeter. Ionizing irradiation induced changes in the frequency distribution of the cellular DNA content of whole testis preparations. These changes can be analysed by flow cytometry. Such measurements deliver information on: (1) an increase of the coefficient of variation of the DNA histograms of some spermatogenic cells, (2) induction of diploid mature sperm, and (3) the dose-depending inactivation of the highly sensitive differentiated spermatogonia. In this model especially No. 3 delivers quantitative information on the cytotoxic action of ionizing irradiation and chemical noxae as well, whereas Nos 1 and 2 may be used as qualitative criteria of mutagenic action of physical and chemical agents. No. 2 obviously being more sensitive than No. 1.

Animals↗
PubMed1980

Flow cytogenetics of uncloned and cloned Chinese hamster cells.

Flow cytometry has greatly facilitated the routine use of DNA content as a cellular indicator of the stages of the cell cycle and ploidy. DNA content can also be used to distinguish individual chromosomes. Fluorescent staining of chromosome DNA was done with a combination of ethidium bromide and mithramycin in hypotonic solution. Subsequent detergent treatment of the cells with Triton X-100 facilitated chromosome isolation. DNA flow cytometry of chromosomes of four established uncloned Chinese master cell lines showed 10 to 12 major subpopulations of chromosomes with varying degrees of overlap in the range of low and intermediate DNA content. Cloning of B14F28 cells, the line with the largest heterogeneity in chromosome number and DNA content, considerably reduced the dispersion in chromosome number and improved the resolution of DNA content distributions. Thus, cloned cells with a relatively homogeneous karyotype permit better discrimination of chromosome subpopulations by DNA content than uncloned cells and provide a more sensitive system to study mutagenic effects.

Animals↗
PubMed1980

Effects of acute gamma-irradiation on spermatogenesis as revealed by flow cytometry.

Mice irradiated with doses ranging from 0.1 to 15 Gy using a 60Co-source and controls were killed at intervals varying from 2 to 35 days after irradiation. The DNA content of the testicular cells in single cell suspensions was measured with the pulse cytophotometer to determine the frequencies of the different stages in the spermatogenesis. The relative amount of S-phase and 4c-cells was reduced initially but increased subsequently to hypernormal values. A decrease of 2c-cells indicated a higher cell-kill of diploid spermatogonia. Gamma ray-induced spermatids with abnormal DNA-values (diploid sperm) were identified. The results suggest that the spermatogenesis can be analysed with flow cytometry and used as a biologic dosimeter even for small doses of ionizing radiation.

Animals↗
PubMed1980

Flow cytometry of DNA content in human bone marrow: a critical reappraisal.

Because cytokinetic studies of the human bone marrow aspirate as a prognostic factor and as a monitor of drug perturbation are frequently inconsistent, we investigated reproducibility of DNA distribution measured by flow cytometry of DNA content in patients with morphologically normal bone marrow. In 15 patients, correlation was noted between DNA distributions simultaneously obtained on right and left iliac crest bone marrow aspirates (r = .588), although considerable variation in individuals was encountered. Much better reproducibility (r = .879) was achieved using bilateral core biopsy of bone marrow in these same patients. In 60 samples, comparison of DNA distribution between bone marrow aspirate and simultaneously obtained biopsy revealed higher relative proportions of S and G2 + M phase cells in biopsies (p less than 0.001), suggesting peripheral blood contamination of aspirate material. Brisk shaking of biopsy specimens in saline expelled a representative sample in the supernatant that could be subjected to simultaneous cytomorphological and cytokinetic analysis. To improve reproducibility of DNA content determinations in normal human bone marrow, bone marrow biopsy should be utilized.

Blood Cell Count↗