The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform

Alejandro Sanchez Alvarado - One of the best experts on this subject based on the ideXlab platform.

  • flow cytometry methods for the study of Cell Cycle Parameters of planarian stem Cells
    Developmental Dynamics, 2009
    Co-Authors: Hara Kang, Alejandro Sanchez Alvarado
    Abstract:

    Due to their characteristic inaccessibility and low numbers, little is known about the Cell-Cycle dynamics of most stem Cells in vivo. A powerful, established methodology to study Cell-Cycle dynamics is flow cytometry, which is used routinely to study the Cell-Cycle dynamics of proliferating Cells in vitro. Its use in heterogeneous mixtures of Cells obtained from whole animals, however, is complicated by the relatively low abundance of cycling to non-cycling Cells. We report on flow cytometric methods that take advantage of the abundance of proliferating stem Cells in the planarian Schmidtea mediterranea. The optimized protocols allow us to measure Cell-Cycle dynamics and follow BrdU-labeled Cells specifically in complex mixtures of Cells. These methods expand on the growing toolkit being developed to study stem Cell biology in planarians, and open the door to detailed cytometric studies of a collectively totipotent population of adult stem Cells in vivo. Developmental Dynamics 238:1111–1117, 2009. © 2009 Wiley-Liss, Inc.

Bruce C Baguley - One of the best experts on this subject based on the ideXlab platform.

  • Relationship of Cell Cycle Parameters to in vitro and in vivo chemosensitivity for a series of Lewis lung carcinoma lines.
    European journal of cancer (Oxford England : 1990), 1992
    Co-Authors: Karen M Holdaway, Graeme J Finlay, Bruce C Baguley
    Abstract:

    The sensitivity of three Lewis lung carcinoma sublines, which grow in culture and in vivo, and vary in in vivo drug sensitivity, have been compared using topoisomerase II poisons amsacrine, amsacrine analogue CI-921, doxorubicin and etoposide. D10 (drug concentration for 10% clonogenic survival) values were determined in vitro for low and high density cultures, and ex vivo for Cells from subcutaneous tumours. The cytokinetic Parameters of these populations were obtained by flow cytometric analysis of bromodeoxyuridine-labelled Cells. Regression analysis showed that logarithmic D10 values were significantly correlated (r greater than 0.95) with G1- and S-phase proportions and highly correlated (r = 0.99) with calculated G1 transit times. The slopes of the regression lines were similar for all topoisomerase II poisons tested and it is suggested that this slope reflects the disappearance of topoisomerase II during G1 phase.

  • relationship of Cell Cycle Parameters to in vitro and in vivo chemosensitivity for a series of lewis lung carcinoma lines
    European Journal of Cancer, 1992
    Co-Authors: Karen M Holdaway, Graeme J Finlay, Bruce C Baguley
    Abstract:

    Abstract The sensitivity of three Lewis lung carcinoma sublines, which grow in culture and in vivo , and vary in in vivo drug sensitivity, have been compared using topoisomerase II poisons amsacrine, amsacrine analogue CI-921, doxorubicin and etoposide. D 10 (drug concentration for 10% clonogenic survival) values were determined in vitro for low and high density cultures, and ex vivo for Cells from subcutaneous tumours. The cytokinetic Parameters of these populations were obtained by flow cytometric analysis of bromodeoxyuridine-labelled Cells. Regression analysis showed that logarithmic D 10 values were significantly correlated ( r > 0.95) with G 1 - and S-phase proportions and highly correlated ( r = 0.99) with calculated G 1 transit times. The slopes of the regression lines were similar for all topoisomerase II poisons tested and it is suggested that this slope reflects the disappearance of topoisomerase II during G 1 phase.

Kirsten Skarstad - One of the best experts on this subject based on the ideXlab platform.

  • an easy to use simulation program demonstrates variations in bacterial Cell Cycle Parameters depending on medium and temperature
    PLOS ONE, 2012
    Co-Authors: Caroline Stokke, Ingvild Flatten, Kirsten Skarstad
    Abstract:

    Many studies are performed on chromosome replication and segregation in Escherichia coli and other bacteria capable of complex replication with C phases spanning several generations. For such investigations an understanding of the replication patterns, including copy numbers of origins and replication forks, is crucial for correct interpretation of the results. Flow cytometry is an important tool for generation of experimental DNA distributions of Cell populations. Here, a Visual Basic based simulation program was written for the computation of theoretical DNA distributions for different choices of Cell Cycle Parameters (C and D phase durations, doubling time etc). These Cell Cycle Parameters can be iterated until the best fit between the experimental and theoretical DNA histograms is obtained. The Excel file containing the simulation software is attached as supporting information. Cultures of Escherichia coli were grown at twelve different media and temperature conditions, with following measurements by flow cytometry and simulation of the DNA distributions. A good fit was found for each growth condition by use of our simulation program. The resulting Cell Cycle Parameters displayed clear inter-media differences in replication patterns, but indicated a high degree of temperature independence for each medium. The exception was the poorest medium (acetate), where the Cells grew with overlapping replication Cycles at 42°C, but without at the lower temperatures. We have developed an easy-to-use tool for determination of bacteria's Cell Cycle Parameters, and consequently the Cells' chromosome configurations. The procedure only requires DNA distribution measurements by flow cytometry. Use of this simulation program for E. coli cultures shows that even Cells growing quite slowly can have overlapping replication Cycles. It is therefore always important not only to assume Cells' replication patterns, but to actually determine the Cell Cycle Parameters when changing growth conditions.

Hara Kang - One of the best experts on this subject based on the ideXlab platform.

  • flow cytometry methods for the study of Cell Cycle Parameters of planarian stem Cells
    Developmental Dynamics, 2009
    Co-Authors: Hara Kang, Alejandro Sanchez Alvarado
    Abstract:

    Due to their characteristic inaccessibility and low numbers, little is known about the Cell-Cycle dynamics of most stem Cells in vivo. A powerful, established methodology to study Cell-Cycle dynamics is flow cytometry, which is used routinely to study the Cell-Cycle dynamics of proliferating Cells in vitro. Its use in heterogeneous mixtures of Cells obtained from whole animals, however, is complicated by the relatively low abundance of cycling to non-cycling Cells. We report on flow cytometric methods that take advantage of the abundance of proliferating stem Cells in the planarian Schmidtea mediterranea. The optimized protocols allow us to measure Cell-Cycle dynamics and follow BrdU-labeled Cells specifically in complex mixtures of Cells. These methods expand on the growing toolkit being developed to study stem Cell biology in planarians, and open the door to detailed cytometric studies of a collectively totipotent population of adult stem Cells in vivo. Developmental Dynamics 238:1111–1117, 2009. © 2009 Wiley-Liss, Inc.

Karen M Holdaway - One of the best experts on this subject based on the ideXlab platform.

  • Relationship of Cell Cycle Parameters to in vitro and in vivo chemosensitivity for a series of Lewis lung carcinoma lines.
    European journal of cancer (Oxford England : 1990), 1992
    Co-Authors: Karen M Holdaway, Graeme J Finlay, Bruce C Baguley
    Abstract:

    The sensitivity of three Lewis lung carcinoma sublines, which grow in culture and in vivo, and vary in in vivo drug sensitivity, have been compared using topoisomerase II poisons amsacrine, amsacrine analogue CI-921, doxorubicin and etoposide. D10 (drug concentration for 10% clonogenic survival) values were determined in vitro for low and high density cultures, and ex vivo for Cells from subcutaneous tumours. The cytokinetic Parameters of these populations were obtained by flow cytometric analysis of bromodeoxyuridine-labelled Cells. Regression analysis showed that logarithmic D10 values were significantly correlated (r greater than 0.95) with G1- and S-phase proportions and highly correlated (r = 0.99) with calculated G1 transit times. The slopes of the regression lines were similar for all topoisomerase II poisons tested and it is suggested that this slope reflects the disappearance of topoisomerase II during G1 phase.

  • relationship of Cell Cycle Parameters to in vitro and in vivo chemosensitivity for a series of lewis lung carcinoma lines
    European Journal of Cancer, 1992
    Co-Authors: Karen M Holdaway, Graeme J Finlay, Bruce C Baguley
    Abstract:

    Abstract The sensitivity of three Lewis lung carcinoma sublines, which grow in culture and in vivo , and vary in in vivo drug sensitivity, have been compared using topoisomerase II poisons amsacrine, amsacrine analogue CI-921, doxorubicin and etoposide. D 10 (drug concentration for 10% clonogenic survival) values were determined in vitro for low and high density cultures, and ex vivo for Cells from subcutaneous tumours. The cytokinetic Parameters of these populations were obtained by flow cytometric analysis of bromodeoxyuridine-labelled Cells. Regression analysis showed that logarithmic D 10 values were significantly correlated ( r > 0.95) with G 1 - and S-phase proportions and highly correlated ( r = 0.99) with calculated G 1 transit times. The slopes of the regression lines were similar for all topoisomerase II poisons tested and it is suggested that this slope reflects the disappearance of topoisomerase II during G 1 phase.