| 1. |
- Allalou, Amin, et al.
(författare)
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Image Based Measurements of Single Cell mtDNA Mutation Load
- 2007
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Ingår i: Image Analysis, Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783540730392 ; , s. 631-640
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Konferensbidrag (refereegranskat)abstract
- Cell cultures as well as cells in tissue always display a certain degree of variability, and measurements based on cell averages will miss important information contained in a heterogeneous population. This paper presents automated methods for image based measurements of mitochondiral DNA (mtDNA) mutations in individual cells. The mitochondria are present in the cell’s cytoplasm, and each cytoplasm has to be delineated. Three different methods for segmentation of cytoplasms are compared and it is shown that automated cytoplasmic delineation can be performed 30 times faster than manual delineation, with an accuracy as high as 87%. The final image based measurements of mitochondrial mutation load are also compared to, and show high agreement with, measurements made using biochemical techniques.
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| 2. |
- Allalou, Amin, et al.
(författare)
-
Image based measurements of single cell mtDNA mutation load MTD 2007
- 2007
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Ingår i: Medicinteknikdagarna 2007.
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Konferensbidrag (populärvet., debatt m.m.)abstract
- Cell cultures as well as cells in tissue always display a certain degree of variability,and measurements based on cell averages will miss important information contained in a heterogeneous population. These differences among cells in a population may be essential to quantify when looking at, e.g., protein expression and mutations in tumor cells which often show high degree of heterogeneity.Single nucleotide mutations in the mithochondrial DNA (mtDNA) can accumulate and later be present in large proportions of the mithocondria causing devastating diseases. To study mtDNA accumulation and segregation one needs to measure the amount of mtDNA mutations in each cell in multiple serial cell culture passages. The different degrees of mutation in a cell culture can be quantified by making measurements on individual cells as an alternative to looking at an average of a population. Fluorescence microscopy in combination with automated digital image analysis provides an efficient approach to this type of single cell analysis.Image analysis software for these types of applications are often complicated and not easy to use for persons lacking extensive knowledge in image analysis, e.g., laboratory personnel. This paper presents a user friendly implementation of an automated method for image based measurements of mtDNA mutations in individual cells detected with padlock probes and rolling-circle amplification (RCA). The mitochondria are present in the cell’s cytoplasm, and here each cytoplasm has to be delineated without the presence of a cytoplasmic stain. Three different methods for segmentation of cytoplasms are compared and it is shown that automated cytoplasmic delineation can be performed 30 times faster than manual delineation, with an accuracy as high as 87%. The final image based measurements of mitochondrial mutation load are also compared to, and show high agreement with, measurements made using biochemical techniques.
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| 3. |
- Allalou, Amin, et al.
(författare)
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Segmentation of Cytoplasms of Cultured Cells
- 2007
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Ingår i: In Proceedings SSBA 2007, Symposium on image analysis, Linköping.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cell cultures as well as cells in tissue always display a certain degree of variability, and measurements based on cell averages will miss important information contained in a heterogeneous population. This paper presents automated methods for segmentation of cells and cytoplasms. The segmentation results are applied to image based measurements of mitochondiral DNA (mtDNA) mutations in individual cells. Three different methods for segmentation of cytoplasms are compared and it is shown that automated cytoplasmic delineation can be performed 30 times faster than manual delineation, with an accuracy as high as 87%, compared to an inter observer variability of 79% at manual delineation.
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| 4. |
- Jahangir Tafrechi, Roshan S., et al.
(författare)
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Single-cell A3243G mitochondrial DNA mutation load assays for segregation analysis
- 2007
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Ingår i: Journal of Histochemistry and Cytochemistry. - 0022-1554 .- 1551-5044. ; 55:11, s. 1159-1166
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Tidskriftsartikel (refereegranskat)abstract
- Segregation of mitochondrial DNA (mtDNA) is an important underlying pathogenic factor in mtDNA mutation accumulation in mitochondrial diseases and aging, but the molecular mechanisms of mtDNA segregation are elusive. Lack of high-throughput single-cell mutation load assays lies at the root of the paucity of studies in which, at the single-cell level, mitotic mtDNA segregation patterns have been analyzed. Here we describe development of a novel fluorescence-based, non-gel PCR restriction fragment length polymorphism method for single-cell A3243G mtDNA mutation load measurement. Results correlated very well with a quantitative in situ Padlock/rolling circle amplification–based genotyping method. In view of the throughput and accuracy of both methods for single-cell A3243G mtDNA mutation load determination, we conclude that they are well suited for segregation analysis.
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| 5. |
- Nilsson, Mats, et al.
(författare)
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Real-time monitoring of rolling-circle amplification using a modified molecular beacon design
- 2002
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 30:14, s. e66-
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Tidskriftsartikel (refereegranskat)abstract
- We describe a method to monitor rolling-circle replication of circular oligonucleotides in dual-color and in real-time using molecular beacons. The method can be used to study the kinetics of the polymerization reaction and to amplify and quantify circularized oligonucleotide probes in a rolling-circle amplification (RCA) reaction. Modified molecular beacons were made of 2'-O-Me-RNA to prevent 3' exonucleolytic degradation by the polymerase used. Moreover, the complement of one of the stem sequences of the molecular beacon was included in the RCA products to avoid fluorescence quenching due to inter-molecular hybridization of neighboring molecular beacons hybridizing to the concatemeric polymerization product. The method allows highly accurate quantification of circularized DNA over a broad concentration range by relating the signal from the test DNA circle to an internal reference DNA circle reporting in a distinct fluorescence color.
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