Use of a spherical multiparameter transducer for flow cytometry

Leif, Robert C.; Cayer, Marilyn L.; Dailey, W.; Stribling, T.; Gordon, Kristie

doi:10.1002/cyto.990200212

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…In the 1970s and 1980s, Hoffman and Britt demonstrated in a flow cytometry system that cells with the same Coulter DC volume could be distinguished using high frequency impedance measurements (38,45). Leif et al developed flow cytometers which integrated Coulter measurement, high frequency impedance, and fluorescence detection (46)(47)(48). Existing impedance-based cytometry systems in the market can be grouped according to their principle of analysis: (1) surface impedance analyzers equipped with electrodes covering the surface of the measurement spot, including chip-based and multiwell-based systems (2); impedance-based flow cytometers conceived mainly for cell counting and sizing applications.…”

Section: Summary Of Impedance-based Cytometers Presently On the Marketmentioning

confidence: 99%

Microfluidic impedance‐based flow cytometry

Berardino²,

et al. 2010

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Microfabricated flow cytometers can detect, count, and analyze cells or particles using microfluidics and electronics to give impedance-based characterization. Such systems are being developed to provide simple, low-cost, label-free, and portable solutions for cell analysis. Recent work using microfabricated systems has demonstrated the capability to analyze micro-organisms, erythrocytes, leukocytes, and animal and human cell lines. Multifrequency impedance measurements can give multiparametric, high-content data that can be used to distinguish cell types. New combinations of microfluidic sample handling design and microscale flow phenomena have been used to focus and position cells within the channel for improved sensitivity. Robust designs will enable focusing at high flowrates while reducing requirements for control over multiple sample and sheath flows. Although microfluidic impedance-based flow cytometers have not yet or may never reach the extremely high throughput of conventional flow cytometers, the advantages of portability, simplicity, and ability to analyze single cells in small populations are, nevertheless, where chip-based cytometry can make a large impact. ' 2010International Society for Advancement of Cytometry Key terms microfluidics; impedance characterization; label free; single cell analysis; hydrodynamic focusing; sorting MICROFLUIDIC flow cytometers can bring many advantages to the field of flow cytometry (FCM). Compared to typical flow cytometry channel sizes, the miniaturized dimensions permit microfluidic systems to analyze single cells, to identify cellular variability in gene expression, or drug response within a cell population. Chipbased cytometers can have lower size and costs than conventional benchtop instruments, and may be portable. Today, the developmental aim for microfluidic systems is to reach the same sensitivity and capability for multiparametric analyses as delivered by conventional flow cytometers. Many efforts have been made to improve existing devices and to create new miniaturized high-end instruments. Microfluidic chips can incorporate on-chip cell preparation, cell culture, lysis, and modules for optical, electrophoretic, or genomic analysis (1). They are also suitable for analysis of cells in suspension as well as adherent cells.Miniaturized cytometry devices will have high impact in the development of point-of-care devices in developing countries. Accurate CD4 1 T-cell counts are used to monitor human immunodeficiency virus (HIV)-infected patients, and various thresholds of the number of CD4 1 T lymphocytes per ll of whole blood are used to start antiretroviral therapy (2-5). A simple, single-purpose CD4 cell counting device, which does not require standard laboratory equipment or trained laboratory personnel, could help some of the 33 million HIV-infected people worldwide monitor the stage of infection (6)(7)(8). In this application, increased analysis throughput is a secondary concern compared to increased sensitivity and specificity. Portable, miniatu...

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Section: Summary Of Impedance-based Cytometers Presently On the Marketmentioning

confidence: 99%

Microfluidic impedance‐based flow cytometry

Berardino²,

et al. 2010

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A short history of the initial application of anti–5‐BrdU to the detection and measurement of S phase

Leif

Stein²,

Zucker

2004

Cytometry Pt A

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Because this article is a bit of history rather than a scientific paper, we will depart from the formality of a journal article. This article has two purposes. The first is to give credit to two deceased individuals, Albert Castro, M.D., and Howard Gratzner, Ph.D. (1). Castro was the key person who was able to produce a polyclonal antibody that was specific for bromodeoxyuridine (BrdU). For 10 years, Gratzner took the lead in converting an idea into a functional assay that affected DNA analysis and led to the development of many other assays with similar methodologies. The second is to inform young scientists that (a) inventions or creations have utility in fields other than the purpose for which they were created; (b) it is possible to do useful work in an institution that certainly would not have been classified as one of the best; and (c) the presence of talented people who are willing to collaborate is invaluable.Scientifically, Gratzner is best known for the development of the first monoclonal antibody (mAb) to BrdU and iododeoxyuridine. This work was the culmination of previous efforts with Robert Leif to develop polyclonal antibodies, which detected BrdU with variable specificity. Collaborations with scientists at the Lawrence Livermore Laboratory encouraged the development of a widely used flow cytometric test for the simultaneous measurements of DNA and BrdU. The use of mAbs to halogenated pyrimidines was a significant scientific advance and currently is an integral tool for the analysis by flow and digital microscopy of the cell cycle.On a personal level, Gratzner's enthusiasm for science and his intelligence, curiosity, loyal interactions with fellow collaborators, and friendship are sorely missed by all who knew him. He was genuinely a warm and nice person who was liked by almost everyone with whom he came in contact (1).Castro was a jovial man who interacted well with his collaborators. He was generous and very knowledgeable. He ran an immunodiagnostics laboratory at the universities of Oregon and Miami and was an expert in the production of antibodies in animals. His warm smile, generous giving of his knowledge, common sense, enthusiasm for scientific research, and ability to get the job done were essential to this project.Because this is a story of events that happened approximately 30 years ago and the existing records are limited, the accuracy of this article is limited by our memory and those of our colleagues who have kindly helped with this project. Of course, this is our version of the events.Cell division and DNA replication are fundamental to biology and specifically to the biology of cancer. This article describes how a simple procedure for the detection and quantitation of DNA synthesis was developed. The precise determination of when S phase occurs in the cell cycle is of use to maximize the selective killing of tumor cells with cycle-specific chemotherapeutic drugs. Of greater significance, studies of the control of the cell cycle, including its detour into apoptosis, can provide extre...

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CytometryML binary data standards

Leif

2005

SPIE Proceedings

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CytometryML is a proposed new Analytical Cytology (Cytomics) data standard, which is based on a common set of XML schemas for encoding flow cytometry and digital microscopy text based data types (metadata). CytometryML schemas reference both DICOM (Digital Imaging and Communications in Medicine) codes and FCS keywords. Flow Cytometry Standard (FCS) list-mode has been mapped to the DICOM Waveform Information Object. The separation of the large binary data objects (list mode and image data) from the XML description of the metadata permits the metadata to be directly displayed, analyzed, and reported with standard commercial software packages; the direct use of XML languages; and direct interfacing with clinical information systems. The separation of the binary data into its own files simplifies parsing because all extraneous header data has been eliminated. The storage of images as two-dimensional arrays without any extraneous data, such as in the Adobe® Photoshop® RAW format, facilitates the development by scientists of their own analysis and visualization software. Adobe Photoshop provided the display infrastructure and the translation facility to interconvert between the image data from commercial formats and RAW format. Similarly, the storage and parsing of list mode binary data type with a group of parameters that are specified at compilation time is straight forward. However when the user is permitted at run-time to select a subset of the parameters and/or specify results of mathematical manipulations, the development of special software was required. The use of CytometryML will permit investigators to be able to create their own interoperable data analysis software and to employ commercially available software to disseminate their data.

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Use of a spherical multiparameter transducer for flow cytometry

Cited by 3 publications

References 10 publications

Microfluidic impedance‐based flow cytometry

Microfluidic impedance‐based flow cytometry

A short history of the initial application of anti–5‐BrdU to the detection and measurement of S phase

CytometryML binary data standards

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