The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
Fiona M Watt - One of the best experts on this subject based on the ideXlab platform.
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β catenin and hedgehog signal strength can specify number and location of hair follicles in adult Epidermis without recruitment of bulge stem cells
Developmental Cell, 2005Co-Authors: Violeta Silvavargas, Kristin M Braun, Cristina Lo Celso, Adam Giangreco, Tyler Ofstad, David M Prowse, Fiona M WattAbstract:Summary Using K14ΔNβ-cateninER transgenic mice, we show that short-term, low-level β-catenin activation stimulates de novo hair follicle formation from sebaceous glands and interfollicular Epidermis, while only sustained, high-level activation induces new follicles from preexisting follicles. The Hedgehog pathway is upregulated by β-catenin activation, and inhibition of Hedgehog signaling converts the low β-catenin phenotype to wild-type Epidermis and the high phenotype to low. β-catenin-induced follicles contain clonogenic keratinocytes that express bulge markers; the follicles induce dermal papillae and provide a niche for melanocytes, and they undergo 4OHT-dependent cycles of growth and regression. New follicles induced in interfollicular Epidermis are derived from that cellular compartment and not through bulge stem cell migration or division. These results demonstrate the remarkable capacity of adult Epidermis to be reprogrammed by titrating β-catenin and Hedgehog signal strength and establish that cells from interfollicular Epidermis can acquire certain characteristics of bulge stem cells.
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transient activation of β catenin signalling in adult mouse Epidermis is sufficient to induce new hair follicles but continuous activation is required to maintain hair follicle tumours
Development, 2004Co-Authors: Cristina Lo Celso, David M Prowse, Fiona M WattAbstract:When β-catenin signalling is disturbed from mid-gestation onwards lineage commitment is profoundly altered in postnatal mouse Epidermis. We have investigated whether adult Epidermis has the capacity forβ -catenin-induced lineage conversion without prior embryonic priming. We fused N-terminally truncated, stabilised β-catenin to the ligand-binding domain of a mutant oestrogen receptor (ΔNβ-cateninER).Δ Nβ-cateninER was expressed in the Epidermis of transgenic mice under the control of the keratin 14 promoter and β-catenin activity was induced in adult Epidermis by topical application of 4-hydroxytamoxifen (4OHT). Within 7 days of daily 4OHT treatment resting hair follicles were recruited into the hair growth cycle and epithelial outgrowths formed from existing hair follicles and from interfollicular Epidermis. The outgrowths expressed Sonic hedgehog, Patched and markers of hair follicle differentiation, indicative of de novo follicle formation. The interfollicular epidermal differentiation program was largely unaffected but after an initial wave of sebaceous gland duplication sebocyte differentiation was inhibited. A single application of 4OHT was as effective as repeated doses in inducing new follicles and growth of existing follicles. Treatment of Epidermis with 4OHT for 21 days resulted in conversion of hair follicles to benign tumours resembling trichofolliculomas. The tumours were dependent on continuous activation of β-catenin and by 28 days after removal of the drug they had largely regressed. We conclude that interfollicular Epidermis and sebaceous glands retain the ability to be reprogrammed in adult life and that continuousβ -catenin signalling is required to maintain hair follicle tumours.
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manipulation of stem cell proliferation and lineage commitment visualisation of label retaining cells in wholemounts of mouse Epidermis
Development, 2003Co-Authors: Kristin M Braun, Catherin Niemann, Uffe Birk Jensen, John P Sundberg, Violeta Silvavargas, Fiona M WattAbstract:Mammalian Epidermis is maintained by stem cells that have the ability to self-renew and generate daughter cells that differentiate along the lineages of the hair follicles, interfollicular Epidermis and sebaceous gland. As stem cells divide infrequently in adult mouse Epidermis, they can be visualised as DNA label-retaining cells (LRC). With whole-mount labelling, we can examine large areas of interfollicular Epidermis and many hair follicles simultaneously, enabling us to evaluate stem cell markers and examine the effects of different stimuli on the LRC population. LRC are not confined to the hair follicle, but also lie in sebaceous glands and interfollicular Epidermis. LRC reside throughout the permanent region of the hair follicle, where they express keratin 15 and lie in a region of high α6β4 integrin expression. LRC are not significantly depleted by successive hair growth cycles. They can, nevertheless, be stimulated to divide by treatment with phorbol ester, resulting in near complete loss of LRC within 12 days. Activation of Myc stimulates epidermal proliferation without depleting LRC and induces differentiation of sebocytes within the interfollicular Epidermis. Expression of N-terminally truncated Lef1 to block β-catenin signalling induces transdifferentiation of hair follicles into interfollicular Epidermis and sebocytes and causes loss of LRC primarily through proliferation. We conclude that LRC are more sensitive to some proliferative stimuli than others and that changes in lineage can occur with or without recruitment of LRC into cycle.
Mrinal Mandal - One of the best experts on this subject based on the ideXlab platform.
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Automated segmentation of regions of interest in whole slide skin histopathological images
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015Co-Authors: Hongming Xu, Cheng Lu, Mrinal MandalAbstract:In the diagnosis of skin melanoma by analyzing histopathological images, the Epidermis and Epidermis-dermis junctional areas are regions of interest as they provide the most important histologic diagnosis features. This paper presents an automated technique for segmenting Epidermis and dermis regions from whole slide skin histopathological images. The proposed technique first performs Epidermis segmentation using a thresholding and thickness measurement based method. The dermis area is then segmented based on a predefined depth of segmentation from the Epidermis outer boundary. Experimental results on 66 different skin images show that the proposed technique can robustly segment regions of interest as desired.
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Efficient segmentation of skin Epidermis in whole slide histopathological images
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015Co-Authors: Hongming Xu, Mrinal MandalAbstract:Segmentation of Epidermis areas is an important step towards automatic analysis of skin histopathological images. This paper presents a robust technique for Epidermis segmentation in whole slide skin histopathological images. The proposed technique first performs a coarse Epidermis segmentation using global thresholding and shape analysis. The Epidermis thickness is then estimated by a series of line segments perpendicular to the main axis of the initially segmented Epidermis mask. If the segmented Epidermis mask has a thickness greater than a predefined threshold, the segmentation is suspected to be inaccurate. A second pass of fine segmentation using k-means algorithm is then carried out over these coarsely segmented result to enhance the performance. Experimental results on 64 different skin histopathological images show that the proposed technique provides a superior performance compared to the existing techniques.
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Automated segmentation and analysis of the Epidermis area in skin histopathological images
2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012Co-Authors: Cheng Lu, Mrinal MandalAbstract:In the diagnosis of skin melanoma by analyzing histopathological images, the segmentation of the Epidermis area is an important step. This paper proposes a computer-aided technique for segmentation and analysis of the Epidermis area in the whole slide skin histopathological images. Before the segmentation technique is employed, a monochromatic color channel that provides a good discriminant information between the Epidermis and dermis areas is determined. In order to reduce the processing time and perform the analysis efficiently, we employ multi-resolution image analysis in the proposed segmentation technique. At first, a low resolution whole slide image is generated. We then segment the low resolution image using a global threshold method and shape analysis. Based on the segmented Epidermis area, the layout of Epidermis is determined and the high resolution image tiles of Epidermis are generated for further manual or automated analysis. Experimental results on 16 different whole slide skin images show that the proposed technique provides a superior performance, about 92% sensitivity rate, 93% precision and 97% specificity rate.
Cheng Lu - One of the best experts on this subject based on the ideXlab platform.
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Automated segmentation of regions of interest in whole slide skin histopathological images
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015Co-Authors: Hongming Xu, Cheng Lu, Mrinal MandalAbstract:In the diagnosis of skin melanoma by analyzing histopathological images, the Epidermis and Epidermis-dermis junctional areas are regions of interest as they provide the most important histologic diagnosis features. This paper presents an automated technique for segmenting Epidermis and dermis regions from whole slide skin histopathological images. The proposed technique first performs Epidermis segmentation using a thresholding and thickness measurement based method. The dermis area is then segmented based on a predefined depth of segmentation from the Epidermis outer boundary. Experimental results on 66 different skin images show that the proposed technique can robustly segment regions of interest as desired.
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Automated segmentation and analysis of the Epidermis area in skin histopathological images
2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012Co-Authors: Cheng Lu, Mrinal MandalAbstract:In the diagnosis of skin melanoma by analyzing histopathological images, the segmentation of the Epidermis area is an important step. This paper proposes a computer-aided technique for segmentation and analysis of the Epidermis area in the whole slide skin histopathological images. Before the segmentation technique is employed, a monochromatic color channel that provides a good discriminant information between the Epidermis and dermis areas is determined. In order to reduce the processing time and perform the analysis efficiently, we employ multi-resolution image analysis in the proposed segmentation technique. At first, a low resolution whole slide image is generated. We then segment the low resolution image using a global threshold method and shape analysis. Based on the segmented Epidermis area, the layout of Epidermis is determined and the high resolution image tiles of Epidermis are generated for further manual or automated analysis. Experimental results on 16 different whole slide skin images show that the proposed technique provides a superior performance, about 92% sensitivity rate, 93% precision and 97% specificity rate.
Violeta Silvavargas - One of the best experts on this subject based on the ideXlab platform.
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β catenin and hedgehog signal strength can specify number and location of hair follicles in adult Epidermis without recruitment of bulge stem cells
Developmental Cell, 2005Co-Authors: Violeta Silvavargas, Kristin M Braun, Cristina Lo Celso, Adam Giangreco, Tyler Ofstad, David M Prowse, Fiona M WattAbstract:Summary Using K14ΔNβ-cateninER transgenic mice, we show that short-term, low-level β-catenin activation stimulates de novo hair follicle formation from sebaceous glands and interfollicular Epidermis, while only sustained, high-level activation induces new follicles from preexisting follicles. The Hedgehog pathway is upregulated by β-catenin activation, and inhibition of Hedgehog signaling converts the low β-catenin phenotype to wild-type Epidermis and the high phenotype to low. β-catenin-induced follicles contain clonogenic keratinocytes that express bulge markers; the follicles induce dermal papillae and provide a niche for melanocytes, and they undergo 4OHT-dependent cycles of growth and regression. New follicles induced in interfollicular Epidermis are derived from that cellular compartment and not through bulge stem cell migration or division. These results demonstrate the remarkable capacity of adult Epidermis to be reprogrammed by titrating β-catenin and Hedgehog signal strength and establish that cells from interfollicular Epidermis can acquire certain characteristics of bulge stem cells.
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manipulation of stem cell proliferation and lineage commitment visualisation of label retaining cells in wholemounts of mouse Epidermis
Development, 2003Co-Authors: Kristin M Braun, Catherin Niemann, Uffe Birk Jensen, John P Sundberg, Violeta Silvavargas, Fiona M WattAbstract:Mammalian Epidermis is maintained by stem cells that have the ability to self-renew and generate daughter cells that differentiate along the lineages of the hair follicles, interfollicular Epidermis and sebaceous gland. As stem cells divide infrequently in adult mouse Epidermis, they can be visualised as DNA label-retaining cells (LRC). With whole-mount labelling, we can examine large areas of interfollicular Epidermis and many hair follicles simultaneously, enabling us to evaluate stem cell markers and examine the effects of different stimuli on the LRC population. LRC are not confined to the hair follicle, but also lie in sebaceous glands and interfollicular Epidermis. LRC reside throughout the permanent region of the hair follicle, where they express keratin 15 and lie in a region of high α6β4 integrin expression. LRC are not significantly depleted by successive hair growth cycles. They can, nevertheless, be stimulated to divide by treatment with phorbol ester, resulting in near complete loss of LRC within 12 days. Activation of Myc stimulates epidermal proliferation without depleting LRC and induces differentiation of sebocytes within the interfollicular Epidermis. Expression of N-terminally truncated Lef1 to block β-catenin signalling induces transdifferentiation of hair follicles into interfollicular Epidermis and sebocytes and causes loss of LRC primarily through proliferation. We conclude that LRC are more sensitive to some proliferative stimuli than others and that changes in lineage can occur with or without recruitment of LRC into cycle.
Kristin M Braun - One of the best experts on this subject based on the ideXlab platform.
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β catenin and hedgehog signal strength can specify number and location of hair follicles in adult Epidermis without recruitment of bulge stem cells
Developmental Cell, 2005Co-Authors: Violeta Silvavargas, Kristin M Braun, Cristina Lo Celso, Adam Giangreco, Tyler Ofstad, David M Prowse, Fiona M WattAbstract:Summary Using K14ΔNβ-cateninER transgenic mice, we show that short-term, low-level β-catenin activation stimulates de novo hair follicle formation from sebaceous glands and interfollicular Epidermis, while only sustained, high-level activation induces new follicles from preexisting follicles. The Hedgehog pathway is upregulated by β-catenin activation, and inhibition of Hedgehog signaling converts the low β-catenin phenotype to wild-type Epidermis and the high phenotype to low. β-catenin-induced follicles contain clonogenic keratinocytes that express bulge markers; the follicles induce dermal papillae and provide a niche for melanocytes, and they undergo 4OHT-dependent cycles of growth and regression. New follicles induced in interfollicular Epidermis are derived from that cellular compartment and not through bulge stem cell migration or division. These results demonstrate the remarkable capacity of adult Epidermis to be reprogrammed by titrating β-catenin and Hedgehog signal strength and establish that cells from interfollicular Epidermis can acquire certain characteristics of bulge stem cells.
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manipulation of stem cell proliferation and lineage commitment visualisation of label retaining cells in wholemounts of mouse Epidermis
Development, 2003Co-Authors: Kristin M Braun, Catherin Niemann, Uffe Birk Jensen, John P Sundberg, Violeta Silvavargas, Fiona M WattAbstract:Mammalian Epidermis is maintained by stem cells that have the ability to self-renew and generate daughter cells that differentiate along the lineages of the hair follicles, interfollicular Epidermis and sebaceous gland. As stem cells divide infrequently in adult mouse Epidermis, they can be visualised as DNA label-retaining cells (LRC). With whole-mount labelling, we can examine large areas of interfollicular Epidermis and many hair follicles simultaneously, enabling us to evaluate stem cell markers and examine the effects of different stimuli on the LRC population. LRC are not confined to the hair follicle, but also lie in sebaceous glands and interfollicular Epidermis. LRC reside throughout the permanent region of the hair follicle, where they express keratin 15 and lie in a region of high α6β4 integrin expression. LRC are not significantly depleted by successive hair growth cycles. They can, nevertheless, be stimulated to divide by treatment with phorbol ester, resulting in near complete loss of LRC within 12 days. Activation of Myc stimulates epidermal proliferation without depleting LRC and induces differentiation of sebocytes within the interfollicular Epidermis. Expression of N-terminally truncated Lef1 to block β-catenin signalling induces transdifferentiation of hair follicles into interfollicular Epidermis and sebocytes and causes loss of LRC primarily through proliferation. We conclude that LRC are more sensitive to some proliferative stimuli than others and that changes in lineage can occur with or without recruitment of LRC into cycle.