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J E Dyson

Publications and source records attributed to J E Dyson.

At least 37 records · Page 2Linked to original sources
PubMed1987

Flow cytometric determination of cell cycle phase-specific changes in cellular phosphatase and glycosidase activities.

The activities of two phosphatases (E.C. 3.1.3.1 and 3.1.4.1) and four glycosidases (E.C. 3.2.1.21, 3.2.1.30, 3.2.1.31 and 3.2.1.51) were measured by fluorescence spectrophotometry, and flow cytometry, in mitogen-stimulated lymphocytes, and in cultures of Molt-4-F and F-89 cell lines, synchronized by hydroxyurea or thymidine. All enzymes were active throughout the cycle but the activities of three enzymes were elevated at specific points in the cycle, alkaline phosphatase activity increased at G2 + M/G1 boundary and in early S-phase, the activity of beta-L fucosidase was elevated in G1 and late S-phase. Orthophosphate diesterase activity was elevated at the G1/S boundary, and during G2 + M. The increase in beta-L fucosidase activity was due to an increased number of cells showing activity, whilst the increase in orthophosphate diesterase activity was attributable to an increase in cellular enzyme activity. Only the activities of orthophosphate diesterase and beta-L fucosidase were measurable by flow cytometry, alkaline phosphatase activity was mainly extracellular, and therefore not detectable by flow cytometric methods employed.

Acetylglucosaminidase↗
PubMed1987

Effects of hyperthermia, irradiation, and cytotoxic drugs on fluorescein isothiocyanate staining intensity for flow cytofluorometry.

Measurement of fluorescein isothiocyanate (FITC) staining intensity of cultured lymphoblastoid cells following hyperthermia showed large increases without concomitant increases in nuclear protein. Similar measurements of cells following incubation with cytotoxic drugs showed fluorescent intensity increases that exceeded the increases in nuclear protein that were due to the cell cycle blocking action of the drug. The reverse, however, was true for cells following irradiation. In contrast, FITC staining intensity and nuclear protein measurements of cells proceeding through the cell cycle after removal of the cycle blocking agent showed nearly parallel changes, although there were reproducible minor differences, especially following blocking with hydroxyurea. These results suggest that FITC staining intensity is a function not only of nuclear protein content but also of stain access to the reaction sites of the protein constituents of the chromatin. Thus, it is possible that FITC staining may be used as a probe of changes in chromatin structure following experimental manipulation of cells in vitro or treatment of tumors in vivo.

Antineoplastic Agents↗
PubMed1987

Prognostic significance of DNA aneuploidy and cell proliferation in rectal adenocarcinomas.

DNA content and cell proliferation were studied retrospectively in 125 patients presenting from 1974-1981 with rectal adenocarcinoma. The presence of DNA aneuploidy or a high level of cell proliferation were associated with a poor prognosis and when combined were the best predictor of survival after Dukes's stage excluding all other pathological assessments investigated. High cell turnover was significantly associated with an infiltrative pattern of growth, an observation that might explain the poorer prognosis of this pattern in rectal adenocarcinomas.

Adenocarcinoma↗
PubMed1987

Flow cytofluorometric evidence for the differential radioresponsiveness of aneuploid and diploid cervix tumours.

We are presently involved in a prospective study of the relationship between DNA content profiles, and their changes during treatment, determined by flow cytofluorometry, and patient prognosis and response to therapy for cancer of the uterine cervix. To date, 348 patients have been included in the study over a 54-month period. Data on these patients have shown that DNA aneuploid tumours are significantly more radioresponsive than diploid cervix tumours. Analysis of the data on 213 patients with a minimum follow-up time of 15 months has, however, failed to show an overall more favourable prognosis conferred by tumour DNA aneuploidy. Analysis of the relationship between clinical stage and disease state and tumour DNA ploidy, however, suggests that aneuploid tumours metastasize to distant sites at an earlier stage of the disease than diploid tumours and local recurrence rates for diploid tumours, in late stage disease, are double those for aneuploid tumours. Improved staining procedures, and instrument modification, has also shown that cervix tumour heterogeneity is of considerably greater frequency than at first appeared to be the case (approximately 75% of DNA aneuploid tumours show heterogeneity.

Aneuploidy↗
PubMed1986

Flow cytometry: methodology and applications in pathology.

Flow cytometry offers pathologists a powerful new method which can be applied especially for diagnosis, prediction of prognosis and measurement of response to therapy of tumours. It also has a wide variety of other applications in research and its use for investigation of non-neoplastic disease has only just begun. The object of this brief review is to stimulate interest in this technique and to outline some of the most interesting applications that may be of use to pathologists in the near future.

Cell Cycle↗
PubMed1986

DNA aneuploidy in colorectal adenomas.

The frequency of DNA aneuploidy was investigated by flow cytometry in 156 colorectal adenomas including 56 associated with 36 synchronous adenocarcinomas. Nine of 156 adenomas (6%) were DNA aneuploid. DNA aneuploidy correlated with increasing size (P less than 0.005) and histopathological type P less than 0.05) but not with dysplasia. Adenomas in associated with a synchronous adenocarcinoma did not have an increased incidence of DNA aneuploidy. Adenocarcinomas found in association with adenomas tend to have a lower incidence of DNA aneuploidy then the generality of colorectal cancers.

Adenocarcinoma↗
PubMed1986

Kinetic and physical studies of cell death induced by chemotherapeutic agents or hyperthermia.

The kinetics of three physical parameters: cell density, relative cytoplasmic viscosity and DNA stability to denaturation have been measured during the period preceding cell death induced by hyperthermia, methylprednisolone and a series of cancer chemotherapeutic agents. This series of measurements employed cultured human lymphoblastoid cells as an experimental system to establish the changes that can be observed in the early stages of cell death, prior to applying such measurements to tissue biopsies from solid human tumours. Cell death, induced by hyperthermia up to 43 degrees C, methylprednisolone, vincristine, 5-fluorouracil, BCNU and melphalan, showed essentially identical and reproducible changes corresponding to those which characterize programmed cell death (apoptosis). Such changes could also be observed following hyperthermia above 43 degrees C, but reproducibility was poor and increasing damage to the cell membranes was evident. In cells treated with adriamycin or methotrexate, cell sub-populations showing an increase in cell density were not detected. Measurements of DNA stability were readily performed by flow cytofluorometry thus allowing rapid quantitation of the fraction of cells in the early stages of cell death. Modified flow cytometric instrumentation would further allow measurement of cytoplastic viscosity as an additional parameter to indicate entry into programmed cell death. This suggests that these measurements could readily be applied to cell suspensions derived from tumour tissue biopsies for a more accurate assessment of tumour growth rate, and to allow monitoring of response to therapy in sequential tumour biopsies.

Antineoplastic Agents↗
PubMed1985

Pre-operative staging of rectal neoplasm and its impact on clinical management.

A sophisticated staging technique (extended staging, ES) employing modern technology has been compared prospectively with conventional clinical assessment (initial staging, IS) in 45 patients with low rectal carcinoma (less than 12 cm from the anal verge) to determine its potential merit and its impact on clinical management. ES consisted of computerized tomography of liver and pelvis, ultrasound scan of liver, measurement of serum concentrations of carcinoembryonic antigen (CEA) and acute phase reactant proteins and multiple superficial and deep biopsies to determine not only the histological grade of the tumour but also its DNA cellular content as measured by flow cytometry. ES proved statistically superior to IS in the assessment of local spread and dissemination. Although histological grade proved to be more accurate on ES than IS this was only true when one specialist pathologist interpreted the slides. When several pathologists were involved interobserver variation made interpretation unreliable. Assessment of DNA content using flow cytometry, being quantitative, was more accurate and perhaps should be used in the future as a prognostic indicator. The improved accuracy of ES would have altered both pre- and intra-operative clinical decisions. It would have prevented some patients receiving inappropriate adjuvant therapy as well as selecting patients more accurately for the correct treatment.

Adult↗
PubMed1985

Heterogeneity of colorectal adenocarcinomas evaluated by flow cytometry and histopathology.

Flow cytometry and histopathology were utilised in evaluating 50 primary and 16 metastatic colorectal carcinomas to determine the influence of heterogeneity and proportion of dying cells on pathological assessments. A new procedure was developed for staining unfixed whole cells with acridine orange and ethidium bromide to quantify DNA and RNA content and number of dead and dying cells. Attempts were made to reduce interobserver variation in histological assessment and to determine whether flow cytometry could refine current grading and staging procedures. Interobserver variation in grading was not improved by estimating proportions of differing grades in multiple samples from individual tumours. Considerable heterogeneity was observed within tumours although this was less apparent when defining ploidy status than histological grade. No consistent differences were observed between superficial and deep parts of tumours or between primary and secondary tumours by either method of analysis. The proportion of dead and dying cells varied widely between tumours but there was no correlation with tumour grade or stage. Non-diploid tumours were not of more advanced stage or poorer histological grade than diploid tumours. Since ploidy status may be an important prognostic factor, analysis of colorectal carcinomas by flow cytometry could be of greater value than conventional grading and staging procedures.

Adenocarcinoma↗
PubMed1985

Quantitation by flow cytofluorometry of response of tumours of the uterine cervix to radiotherapy.

We are presently involved in a project to investigate the use of flow cytofluorometry in assessing, by means of serial biopsies, the response to radiotherapy of tumours of the uterine cervix. This technique enables changes in the DNA content profiles and content of proliferating cells in the tumour biopsies to be determined at intervals as therapy progresses. A means has been devised to quantitate the content of hyperdiploid cells, hypertetraploid cells, and dead and dying cells, by computer analysis of DNA vs. RNA scattergrams obtained by flow cytofluorometric analysis. Plotting of these parameters for the serial biopsies vs. time since start of tumour irradiation presents a graphical indication of the response of the tumour to irradiation. Over 100 patients (stage Ib and IIa) have been followed during intracavitary (Cathetron) therapy with parallel flow cytofluorometric analysis and histopathological assessment of serial biopsies. Patterns are beginning to emerge from these analyses which promise to indicate within 14-21 days and sometimes earlier the extent of radioresponsiveness of the tumour. These patterns may also be of assistance in planning modified dose fractionation schedules to obtain improved therapeutic ratios.

Acridine Orange↗
PubMed1984

Flow cytofluorometric analysis of serial biopsies of tumours of the uterine cervix.

The technique of flow cytofluorometry has been employed to assess, by means of cell suspensions prepared from serial biopsies, the radioresponsiveness of tumours of the uterine cervix. This enables DNA profiles and content of proliferating cells to be determined prior to treatment and during external beam and intracavitary therapy. Results show that elimination of hyperdiploid and hypertetraploid cells and reduction in the proliferating fraction of cells can readily be monitored by this method during therapy. This information, quickly available during treatment, may assist in estimating radioresponsiveness of the tumour and possible prognosis for the patient. Dose fractionation schedules may also be adjusted according to tumour response to therapy. Our results, however, show no relationship between histopathological classification of a tumour (WHO) and its ploidy state. The advanced stages of the disease (II and III) do, however, show an increased content of hypertetraploid cells in the tumour biopsies.

Brachytherapy↗
PubMed1984

Relationship between cell ploidy and glucocorticoid induced death in human lymphoid cell lines.

We have found a relationship between sensitivity to glucocorticoid induced cell death (at 10 microM glucocorticoid) and ploidy in the human lymphoid cell line CCRF/CEM-C7. Most sensitive clones are diploid, whilst resistant clones and the resistant parent line CCRF/CEM are tetraploid. Diploid sensitive clones have a tendency to become aneuploid within a few months of isolation, with alterations in their kinetic responses to glucocorticoids. This is followed by a doubling in DNA content which results in reversion to the tetraploid glucocorticoid resistant state of the parent line CCRF/CEM. A few sensitive clones have been found to be tetraploid but with different kinetic responses to glucocorticoids as compared to diploid clones. The principal difference being an extended lag period (48-72 h) prior to lethal response. The relationship between ploidy and glucocorticoid sensitivity does not appear to extend to other human lymphoid cell lines.

Cell Line↗
PubMed1980

Lymphocyte supernatants and the electrophoretic mobility of erythrocytes: further experience of cancer diagnosis.

A double-blind trial of the tanned-erythrocyte electrophoretic mobility test for cancer has been carried out. This included 70 normal subjects as controls, 61 subjects with disease other than cancer, and 229 cancer patients. Slowing values generally increased in the order given, with certain diseases having values within the range positive for cancer. Exposure to viral infection also tended to produce false positives. Slowing values above 50%, however, appear to be definitely associated with cancer. For the middle range of slowing values (25-50%) there is some overlap between the 3 groups, so that a statistical probability of the presence of malignancy is available from the test. With slowing values below 25% there is little likelhood of cancer. Tumour type influences the test result, as does, to a lesser extent, tumour bulk.

Adult↗
PubMed1978

Effect of lymphocyte supernatants on the electrophoretic mobility of erythrocytes: significance in cancer diagnosis.

We have determined that when an extract of human brain is preincubated with lymphocytes its subsequent capacity to inhibit the electrophoretic mobility of tanned and stabilized erythrocytes is much reduced. There is a differential effect, however, as the observed reduction is from 73% inhibition to approximately 35% when the pre-incubation is with lymphocytes from patients with malignant disease, but from 73% to approximately 10% when it is with lymphocytes from normal controls. These values were obtained at a brain extract concentration of 333 microgram/ml, with 5 times 10(6) lymphocytes, a pre-incubation time of 18-24 h, and a temperature of 27 degrees C, which are the optimum conditions determined for differentiation between cancer patients and normal subjects. In a series of 73 subjects tested by this method 43/51 cancer patients gave an unequivocal "positive" value, 22/22 normal controls gave a "negative" value, with no false positives.

Adult↗