Biomedical subjects

S E Shackney

Publications and source records attributed to S E Shackney.

At least 37 records · Page 2Linked to original sources

PubMed1990

ViVACCy--a drug schedule based on G2 blockade and prolonged infusion of multiple tubulin-binding agents. A pilot study.

A drug schedule has been devised based on a strategy of G2 blockade followed by prolonged infusion of tubulin-binding agents. The regimen consists of doxorubicin 32 mg/m2 i.v. and cyclophosphamide 320 mg/m2 i.v. on day 1 followed by vinblastine (0.3 to 1.2 mg/m2/day), cisplatin (3 to 12 mg/m2/day), and vincristine (0.04 to 0.16 mg/m2/day) by continuous intravenous infusion on days 5 to 12. Courses are repeated every 28 days. Eighteen patients with advanced solid tumors received 37 courses of chemotherapy in a pilot study to determine safe drug concentrations for the three-drug infusion for 7 days. Dose limiting toxicity was myelosuppression. Patients who received prior mitomycin-C experienced more profound thrombocytopenia than those who did not. Nonhematologic toxicities included mild nausea, vomiting, and transient elevations of serum alkaline phosphatase and serum creatinine. One patient with squamous cell carcinoma of the esophagus who erroneously received vincristine 0.8 mg/m2 instead of 0.08 mg/m2 for 4 1/2 days developed transient myalgia, ileus, and a transient peripheral neuropathy; the patient achieved a sustained complete remission for 15 months and died of unrelated causes. Minor responses and stable disease were seen in two patients with renal cell carcinoma (1 and 2.5 months), three patients with colorectal carcinoma (1.5, 2, and 4 months), and one patient with squamous cell carcinoma of the tongue (2 months). The ViVACCy drug regimen can be given without undue toxicity and may be active in solid tumors.

Adult↗

PubMed1990

Discrepancies between flow cytometric and cytogenetic studies in the detection of aneuploidy in human solid tumors.

Parallel flow cytometric (FCM) cell DNA studies and cytogenetic studies were performed on clinical samples from twenty human solid tumors of various types and on cell lines established in tissue culture from three of these tumors. Six of twenty clinical samples (30%) showed concordance between flow cytometry and cytogenetics with respect to the presence or absence of aneuploidy. Among the fourteen cases with discrepancies between the two methods, 8 (40% of all cases) showed hypodiploidy by cytogenetics and had diploid DNA histograms. Three cases (15%) had prominent discrete peaks in the triploid to tetraploid region by cytogenetics but had only barely discernible corresponding peaks in the DNA histogram. In two cases (10%) cytogenetic studies revealed diffuse aneuploidy. Cytogenetic studies demonstrated near-tetraploidy in three samples, but only one of these was detected by FCM; all three cases exhibited other numerical chromosomal abnormalities. In one case aneuploidy was demonstrated by FCM and not by cytogenetics. Among the tumor cell lines established in culture, the DNA Index was often higher than the cytogenetic index. Overall, 13/20 or 65% of patients with solid tumors in this study had numerical chromosomal abnormalities that were not detected by flow cytometry. Eleven of these patients had distant metastases at the time of tumor sampling, and nine of these died of their disease within 1-11 months of the time of study.

Aneuploidy↗

PubMed1990

Flow cytometric S fraction as a predictor of clinical outcome in cystosarcoma phyllodes.

Clinicopathologic characteristics were evaluated in 20 cases of cystosarcoma phyllodes in relation to clinical outcome. Flow cytometric DNA studies were carried out in 15 of these 20 cases. Stromal overgrowth and an infiltrating tumor border emerged as prominent histopathologic features that were associated with an unfavorable clinical outcome. Flow cytometric S fractions greater than 0.05 were associated with poor clinical outcome. There was no correlation between tumor ploidy and clinical outcome. There were no direct correlations between clinicopathologic features and flow cytometric measurements. Our data suggest that flow cytometric S fractions may be a useful predictor of clinical outcome in cystosarcoma phyllodes that can complement the traditional histologic analysis of these rare breast tumors.

Adolescent↗

PubMed1989

Model for the genetic evolution of human solid tumors.

A conceptual model is proposed for the genetic evolution of many human solid tumors that is based on the observations that cancer cells may spontaneously double their chromosome number; that cells with excessive chromosome numbers may be cytogenetically unstable, both losing chromosomes randomly during subsequent cell divisions, and often developing structural abnormalities in the chromosomes that are retained; and that some structural chromosome abnormalities may activate growth-promoting genes. The sequence of tetraploidization with chromosome loss can occur repeatedly in a given tumor. The available evidence supporting the model is reviewed. A computer simulation system that embodies these concepts is described and the model is used to generate distributions of chromosome number/cell under various simulated conditions and in a variety of simulated biological settings. A simulation of the time course of changes in chromosome number per cell that accompany the spontaneous neoplastic transformation of mouse fibroblasts in vitro is described. The best fit to the data was obtained when provision was made for the activation of at least two growth-promoting genes. The conditions for generating discrete aneuploid peaks in cytogenetic and flow cytometric studies were explored; our modeling studies suggest that the activation of a growth promoting gene is required in order to produce a discrete aneuploid peak. Our modeling studies suggest that the overrepresentation of individual oncogene-bearing chromosomes in aneuploid cell lines may require the activation of gene dose-dependent growth-promoting genes and is not likely to occur in cell lines in which at least two copies of each normal chromosome are required for cell survival. Overall, the results obtained using the model are consistent with a wide variety of flow cytometric and cytogenetic studies in human solid tumors.

Animals↗

PubMed1989

Karyotypic evolution of a human undifferentiated large cell carcinoma of the lung in tissue culture.

Serial cytogenetic studies were performed on a cell line derived from a pleural effusion from a patient with undifferentiated large cell carcinoma of the lung. The initial sample had a broad range of chromosome numbers per cell, with a hypodiploid/pseudodiploid stem line and a hypotetraploid sideline. A sequence consisting of a doubling of chromosome number per cell followed by chromosome loss was observed repeatedly during 40 culture passages. The presence of metaphase spreads showing evidence of endoreduplication suggested this as a likely mechanism for the doubling of chromosome number per cell. Eleven marker chromosomes were observed in the cells of the primary sample; these markers persisted through all subsequent passages. Chromosomes 1, 2, 6, 7, 8, 11, and 16 were consistently overrepresented; each of these chromosomes was involved in marker formation. Chromosomes 4, 5, 9, 10, 19, 21, and 22 were consistently underrepresented. Every chromosome, either in its normal form and/or as part of a marker, was represented on the average by at least one copy per diploid cell. Eighteen new marker chromosomes were observed during the course of cell cultivation; one of these evolved into a clonal marker over the course of six cell passages. Of the new marker chromosomes that were formed during the observation period, the majority were found in hypotetraploid cells.

Carcinoma↗

PubMed1987

Radiation-induced leiomyosarcoma of the great vessels presenting as superior vena cava syndrome.

A patient with a pleomorphic intravascular leiomyosarcoma of the great vessels of the neck and mediastinum presented clinically with a superior vena cava syndrome. A latent period of 29 years elapsed between receiving orthovoltage radiation to the neck and right side of chest to treat recurrent ganglioneuroblastoma, and the appearance of a leiomyosarcoma and subsequent recurrences. The patient underwent partial resection of the tumor, received adjunct chemotherapy, and was shown to be free of disease by clinical tests and by magnetic resonance imaging (MRI) 17 months after completion of chemotherapy. The criteria for the diagnosis of radiation-induced sarcomas are reviewed in relation to the present case. The critical role of magnetic resonance imaging in both the diagnosis and continued follow-up of the patient is described. This would appear to be the first reported case of radiation-induced intravascular leiomyosarcoma of the great vessels of the neck and mediastinum presenting as a superior vena cava syndrome.

Adult↗

PubMed1987

Pseudo-Gaucher cells in the bone marrow of a patient with Hodgkin's disease.

The authors studied an 18-year-old woman with stage IIIB nodular sclerosis Hodgkin's disease whose bone marrow contained abnormal storage cells that resembled Gaucher cells by light microscopic examination ("pseudo-Gaucher" cells). Electron microscopic examination revealed that these cells differed from true Gaucher cells and resembled storage cells previously described in chronic myelogenous leukemia. The patient's peripheral blood leukocyte beta-glucosidase and serum acid phosphatase levels were elevated, ruling out the diagnosis of inherited Gaucher's disease. After treatment with six monthly cycles of systemic chemotherapy (nitrogen mustard, vincristine, procarbazine, bleomycin, doxorubicin, and prednisone), all signs of Hodgkin's disease and pseudo-Gaucher cells disappeared. Repeat leukocyte beta-glucosidase and serum acid phosphatase levels were unchanged. The present case is unique with its documentation of classical enzyme patterns for beta-glucosidase and acid phosphatase and electron microscopic features. The authors postulate that pseudo-Gaucher cells result from excessive cell breakdown with an overload of available beta-glucosidase.

Acid Phosphatase↗

PubMed1986

Count-dependent filter for smoothing bivariate FCM histograms.

A data-smoothing filter has been developed that permits the improvement in accuracy of individual elements of a bivariate flow cytometry (FCM) histogram by making use of data from adjacent elements, a knowledge of the two-dimensional measurement system point spread function (PSF), and the local count density. For FCM data, the PSF is assumed to be a set of two-dimensional Gaussian functions with a constant coefficient of variation for each axis. A set of space variant smoothing kernels are developed from the basic PSF by adjusting the orthogonal standard deviations of each Gaussian smoothing kernel according to the local count density. This adjustment in kernel size matches the degree of smoothing to the local reliability of the data. When the count density is high, a small kernel is sufficient. When the density is low, however, a broader kernel should be used. The local count density is taken from a region defined by the measurement PSF. The smoothing algorithm permits the reduction in statistical fluctuations present in bivariate FCM histograms due to the low count densities often encountered in some elements. This reduction in high-frequency spatial noise aids in the visual interpretation of the data. Additionally, by making more efficient use of smaller samples, systematic errors due to system drift may be minimized.

Cell Count↗

PubMed1986

The use of flow cytometry in the diagnosis and biological characterization of the non-Hodgkin's lymphomas.

The detection of aneuploidy and the estimation of the fraction of cells in S in DNA histograms from patients with human non-Hodgkin's lymphoma are reviewed. Karyotype studies and DNA histograms each have advantages and disadvantages in the detection and monitoring of aneuploidy. The choice of fluorescent stain, staining artifacts, and the criteria for the detection of aneuploidy by FCM must be considered carefully. In general, the B-cell lymphomas are more frequently aneuploid by FCM than the T-cell lymphomas. When determining S fractions in the lymphomas, care must be taken not to exclude the aneuploid cases on methodological grounds; these cases generally have the highest S fractions and their exclusion would bias the data. Multiparameter studies have shown that the most aneuploid component of a mixed clinical sample generally has the highest S fraction in the sample, favoring the concept of clonal selection and clonal evolution of tumors.

Aneuploidy↗

PubMed1986

Quantitative changes in surface immunoglobulin expression in WEHI-231 lymphoma cells in relation to their proliferative rate.

Quantitative changes in surface immunoglobulin expression were studied in relation to the proliferative behavior of WEHI-231 cells. They undergo morphologic, biochemical and immunologic changes during the course of growth in culture. Changes in cell size and morphology, as well as DNA and RNA synthesis, resemble features of normal lymphocyte transformation. During log phase growth there was a more than 30-fold increase in cell number over a 4-day period in the absence of medium change. The average log phase population doubling time was 20 h. Plateau phase was achieved on day 5, and maintained through day 7. Image analysis studies of cytocentrifuged cells demonstrated increases in cell, and nuclear area that became apparent within 2 h of transplantation. Tritiated thymidine incorporation rose rapidly peaking on days 2 and 3, and then fell progressively to 35% of peak values on day 4. Tritiated uridine incorporation into RNA showed similar changes. Changes in S fraction, as determined by flow cytometry, paralleled the changes in tritiated thymidine incorporation. Cell surface IgM and kappa light-chain immunoglobulin were also measured by flow cytometry. Mean values were low initially, rose slowly, increased rapidly to peak values on days 3 and 4, and then fell progressively. Peak surface immunoglobulin levels were observed during the transition of cells from log phase to plateau phase growth, and coincided with the appearance of large numbers of small cells with low rates of DNA and RNA synthesis. Thus, maximum expression of surface Ig was associated with growth retardation, and not with early rapid growth phase. The maximal expression of surface immunoglobulin in small slowly proliferating cells may have important implications for immunotherapy with monoclonal antibodies alone.

Animals↗

PubMed1985

The relationship between mean channel selection and the calculated coefficient of variation.

Calculated coefficients of variation (CV) taken from the quotient of the standard deviation (S.D.) and the mean value of measured distributions are often used as an indicator of system performance in linear flow cytometry (FCM). The ability of the calculated CV to estimate the true CV of the underlying experiment before grouping (channelization) is dependent on the relationship between the width of the data channels and the magnitude of the S.D. of the measured distribution. When the channel width is equal to the S.D. of a distribution, the calculated CV is approximately 20% larger than the true CV of an experiment. By the time the S.D. is only one-half of a channel width, the calculated CV is unreliable. When the distribution S.D. is narrower than a channel's width, small changes in the distribution mean value will cause large variations in the calculated CV. As the true CV decreases, the calculation must be made with higher mean channel values. This dependence of calculated CV accuracy upon the relationship between S.D. and channel width places limitations upon mean channel selection that must be considered when using CV calculations for evaluating system performance, especially when looking for small improvements during optical alignment procedures. When an instrument is assumed to have a constant CV and the data are collected linearly, it is possible to improve the CV estimation accuracy by placing distributions in higher-numbered channels.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow Cytometry↗

PubMed1984

A count-dependent filter for smoothing flow cytometric histograms.

An adaptive count-dependent algorithm for smoothing statistically limited histograms has been developed. It considers both the spatial frequency limitations of the measurement system (described by the measurement system point spread function) and the reliability of the measured data (indicated by the effective number of counts influencing each channel of the histogram. Windows for smoothing flow cytometric histograms are derived from an assumed Gaussian-shaped point spread function (PSF) with a constant coefficient of variation. The windows are developed by scaling the variances of the Gaussian functions inversely with the statistical reliability of the data contained in each channel of the measured histogram. The reliability of this data is determined by taking the square root of the number of counts influencing the value tabulated for each channel. Using the algorithm, a smoothed version of the measured histogram may be developed from a linear sum of the products of the individual scaled Gaussian functions and the original measured histogram. Data are presented demonstrating the advantages of count-dependent smoothing over non-count-dependent smoothing using synthesized DNA histograms as a function of sample size.

Cell Cycle↗

PubMed1984

Design of flow chamber with electronic cell volume capability and light detection optics for multilaser flow cytometry.

A multibeam optical detection system has been developed with a high optical efficiency, achieved through a reduction in the number of optical interfaces employed in the system. This reduction is made possible by a combination of employing simple lenses, gluing the objective lens directly upon the face of the flow cuvette and the extraction of only one fluorescence signal from each laser beam. A modified flow chamber is also described that includes fluidic resistance elements for the elimination of most of the electric shielding normally associated with electronic cell volume measurements.

Animals↗

PubMed1984

The biology of tumor growth in the non-Hodgkin's lymphomas. A dual parameter flow cytometry study of 220 cases.

Dual parameter flow cytometry studies (cell DNA content and electronic cell volume) were performed in 220 cases of non-Hodgkin's lymphoma. All cases were characterized as B or T cell malignancies, based on immunologic surface marker characteristics. Aneuploidy by flow cytometry was more common among the B cell lymphomas than among the T cell lymphomas, and was most common among the large B cell lymphomas and B cell lymphomas of intermediate size. Ploidy index distributions showed a prominent hyperdiploid peak, as well as tumor cell populations with near-tetraploid DNA contents. In serial studies, a decrease in ploidy index was observed in association with clinical and histologic transformation in one case. The highest S fractions were observed among the large and intermediate B cell lymphomas and among the aggressive T cell lymphomas. In clinical samples consisting of mixtures of diploid and aneuploid populations, the data on the aneuploid components could often be separated from other components of the mixture in multiparameter studies on the basis of the larger electronic cell volumes of the aneuploid cells. In each case, the aneuploid large cell component almost invariably had a higher S fraction than the residual component(s) of the mixture. Overall, the data are consistent with a model of clonal selection and clonal evolution in the lymphomas in which early cytogenetic abnormalities that involve little or no change in total cell DNA content are followed by cell tetraploidization that is associated with cytogenetic instability and chromosome loss over the course of time.

Aneuploidy↗

PubMed1983

High resolution method for the analysis of DNA histograms that is suitable for the detection of multiple aneuploid G1 peaks in clinical samples.

The DNA histogram obtained by flow cytometry can be considered as the product of an "ideal" measurement column vector and a measurement distortion matrix. In order to extract the ideal histogram from the real data, the measurement distortion matrix is commonly presumed to be a family of Gaussian coefficients that are centered on the diagonal. We have designed a feedback-controlled curve-fitting procedure that reconstructs the ideal histogram from the real data through successive iterations. The optimum coefficient of variation (cv) for the family of Gaussians in the measurement distortion matrix is determined from an analysis of the sums of squares of fits of the computed DNA histogram to the real data over an appropriate range of trial cv. Since this method assigns a Gaussian to each and every data channel, it permits the resolution of closely spaced multiple aneuploid G1 peaks in clinical samples. The effects of high frequency noise that may be present in the data can be attenuated by multiplying the real data histogram by a Gaussian matrix with cv close to but smaller than that of the measurement distortion matrix.

Aneuploidy↗

PubMed1983

A practical graphical method for estimating the fraction of cells in S in DNA histograms from clinical tumor samples containing aneuploid cell populations.

A graphical method for the analysis of unperturbed DNA histograms is presented in which the area of the normalized histogram subtended by the fraction of cells in S is represented by a trapezoid whose dimensions are dependent on features common to all such histograms. The technique takes measurement variability into account. This method was applied to a variety of synthetic DNA histograms. Overall, calculated values for the fraction of cells in S correlated well with actual values. This method was applied to 36 diploid cases of non-Hodgkin lymphoma; results correlated well with those obtained by a computer-based method. The results of the graphical-method were also highly reproducible between different observers. The graphical method can be used in the presence of aneuploid cell populations. Techniques for calculating S fractions in the presence of aneuploidy in clinical samples are described. These techniques were applied to synthetic histograms of mixed diploid and aneuploid populations. Calculated values correlated well with actual values.

Aneuploidy↗

PubMed1983

Automated radioautographic grain counting. Correction for grain overlap.

An algorithm is described for the calculation of radioautographic cell grain count from measurements of total cell nuclear area and total grain area. This algorithm provides a statistical correction for grain overlap that is based on the solution to the occupancy problem in probability theory. This method permits the use of automated grain counting over a wide range of grain counts per cell, and extends the useful dynamic range of radioautographic grain counting to well over 200 grains/cell.

Autoradiography↗

PubMed1983

Effects of vincristine on cell survival, cell cycle progression, and mitotic accumulation in asynchronously growing Sarcoma 180 cells.

The effects of vincristine (VCR) on cell survival, cell cycle progression, DNA synthesis, and metaphase accumulation were studied in relation to drug concentration and drug exposure duration in Sarcoma 180 cells in vitro. VCR was found to affect cells in interphase, producing a transient G2 block at all drug concentrations and drug exposure durations studied. VCR did not affect DNA synthesis directly. Increases in the metaphase index were delayed and always peaked at approximately 8 hr after drug removal, regardless of the duration of drug exposure. Increases in the metaphase index of sufficient magnitude to be commensurate with VCR lethality were observed only with prolonged drug exposure. VCR produced both nuclear fragmentation and polyploidy. The proportion of cells undergoing polyploidy increased progressively with increasing drug exposure duration. Interference with cytokinesis during prolonged VCR exposure may represent a lethal effect of VCR that is separate from its short-term effects. This could serve as the basis for the clinical study of the antitumor effects of prolonged VCR infusions.

Animals↗