Automated Segmentation and Object Classification of CT Images: Application toIn VivoMolecular Imaging of Avian Embryos

Background. Although chick embryogenesis has been studied extensively, there has been growing interest in the investigation of skeletogenesis. In addition to improved poultry health and minimized economic loss, a greater understanding of skeletal abnormalities can also have implications for human medicine. Truein vivostudies require noninvasive imaging techniques such as high-resolution microCT. However, the manual analysis of acquired images is both time consuming and subjective.Methods. We have developed a system for automated image segmentation that entails object-based image analysis followed by the classification of the extracted image objects. For image segmentation, a rule set was developed using Definiens image analysis software. The classification engine was implemented using the WEKA machine learning tool.Results. Our system reduces analysis time and observer bias while maintaining high accuracy. Applying the system to the quantification of long bone growth has allowed us to present the first truein ovodata for bone length growth recorded in the same chick embryos.Conclusions. The procedures developed represent an innovative approach for the automated segmentation, classification, quantification, and visualization of microCT images. MicroCT offers the possibility of performing longitudinal studies and thereby provides unique insights into the morpho- and embryogenesis of live chick embryos.

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Rac signaling in osteoblastic cells is required for normal bone development but is dispensable for hematopoietic development

Blood ◽

10.1182/blood-2011-07-368753 ◽

2012 ◽

Vol 119 (3) ◽

pp. 736-744 ◽

Cited By ~ 16

Author(s):

Steven W. Lane ◽

Serena De Vita ◽

Kylie A. Alexander ◽

Ruchan Karaman ◽

Michael D. Milsom ◽

...

Keyword(s):

Bone Growth ◽

Bone Development ◽

Long Bone ◽

Perivascular Niche ◽

Hematopoietic Stem ◽

Hsc Niche ◽

Rac1 Gtpase

Abstract Hematopoietic stem cells (HSCs) interact with osteoblastic, stromal, and vascular components of the BM hematopoietic microenvironment (HM) that are required for the maintenance of long-term self-renewal in vivo. Osteoblasts have been reported to be a critical cell type making up the HSC niche in vivo. Rac1 GTPase has been implicated in adhesion, spreading, and differentiation of osteoblast cell lines and is critical for HSC engraftment and retention. Recent data suggest a differential role of GTPases in endosteal/osteoblastic versus perivascular niche function. However, whether Rac signaling pathways are also necessary in the cell-extrinsic control of HSC function within the HM has not been examined. In the present study, genetic and inducible models of Rac deletion were used to demonstrate that Rac depletion causes impaired proliferation and induction of apoptosis in the OP9 cell line and in primary BM stromal cells. Deletion of Rac proteins caused reduced trabecular and cortical long bone growth in vivo. Surprisingly, HSC function and maintenance of hematopoiesis in vivo was preserved despite these substantial cell-extrinsic changes. These data have implications for therapeutic strategies to target Rac signaling in HSC mobilization and in the treatment of leukemia and provide clarification to our evolving concepts of HSC-HM interactions.

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The Chorioallantoic Membrane Assay in Nanotoxicological Research—An Alternative for In Vivo Experimentation

Nanomaterials ◽

10.3390/nano10122328 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2328

Author(s):

Christoph R. Buhr ◽

Nadine Wiesmann ◽

Rachel C. Tanner ◽

Jürgen Brieger ◽

Jonas Eckrich

Keyword(s):

Imaging Techniques ◽

Chorioallantoic Membrane ◽

Drug Carriers ◽

Human Organism ◽

Cam Assay ◽

In Ovo ◽

In Vivo Models ◽

Toxicological Profile ◽

Application Fields

Nanomaterials unveil many applicational possibilities for technical and medical purposes, which range from imaging techniques to the use as drug carriers. Prior to any human application, analysis of undesired effects and characterization of their toxicological profile is mandatory. To address this topic, animal models, and rodent models in particular, are most frequently used. However, as the reproducibility and transferability to the human organism of animal experimental data is increasingly questioned and the awareness of animal welfare in society increases at the same time, methodological alternatives are urgently required. The chorioallantoic membrane (CAM) assay is an increasingly popular in ovo experimental organism suitable for replacement of rodent experimentation. In this review, we outline several application fields for the CAM assay in the field of nanotoxicology. Furthermore, analytical methods applicable with this model were evaluated in detail. We further discuss ethical, financial, and bureaucratic aspects and benchmark the assay with other established in vivo models such as rodents.

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Engrailed defines the position of dorsal di-mesencephalic boundary by repressing diencephalic fate

Development ◽

10.1242/dev.126.22.5127 ◽

1999 ◽

Vol 126 (22) ◽

pp. 5127-5135 ◽

Cited By ~ 8

Author(s):

I. Araki ◽

H. Nakamura

Keyword(s):

Molecular Mechanisms ◽

Chimeric Protein ◽

Negative Regulator ◽

Chick Embryos ◽

Wild Type ◽

In Ovo ◽

Positive Form ◽

In Ovo Electroporation ◽

The Brain

Regionalization of a simple neural tube is a fundamental event during the development of central nervous system. To analyze in vivo the molecular mechanisms underlying the development of mesencephalon, we ectopically expressed Engrailed, which is expressed in developing mesencephalon, in the brain of chick embryos by in ovo electroporation. Misexpression of Engrailed caused a rostral shift of the di-mesencephalic boundary, and caused transformation of dorsal diencephalon into tectum, a derivative of dorsal mesencephalon. Ectopic Engrailed rapidly repressed Pax-6, a marker for diencephalon, which preceded the induction of mesencephalon-related genes such as Pax-2, Pax-5, Fgf8, Wnt-1 and EphrinA2. In contrast, a mutant Engrailed, En-2(F51rE), bearing mutation in EH1 domain, which has been shown to interact with a co-repressor, Groucho, did not show the phenotype induced by wild-type Engrailed. Furthermore, VP16-Engrailed chimeric protein, the dominant positive form of Engrailed, caused caudal shift of di-mesencephalic boundary and ectopic Pax-6 expression in mesencephalon. These data suggest that (1) Engrailed defines the position of dorsal di-mesencephalic boundary by directly repressing diencephalic fate, and (2) Engrailed positively regulates the expression of mesencephalon-related genes by repressing the expression of their negative regulator(s).

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Monitoring of tumor growth and vascularization with repetitive ultrasonography in the chicken chorioallantoic-membrane-assay

Scientific Reports ◽

10.1038/s41598-020-75660-y ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Jonas Eckrich ◽

Philipp Kugler ◽

Christoph Raphael Buhr ◽

Benjamin Philipp Ernst ◽

Simone Mendler ◽

...

Keyword(s):

Tumor Growth ◽

Tumor Imaging ◽

Imaging Techniques ◽

Chorioallantoic Membrane ◽

Cam Assay ◽

In Ovo ◽

Tumor Research ◽

Xenograft Models ◽

Cost Efficient

Abstract The chorioallantoic-membrane (CAM)-assay is an established model for in vivo tumor research. Contrary to rodent-xenograft-models, the CAM-assay does not require breeding of immunodeficient strains due to native immunodeficiency. This allows xenografts to grow on the non-innervated CAM without pain or impairment for the embryo. Considering multidirectional tumor growth, limited monitoring capability of tumor size is the main methodological limitation of the CAM-assay for tumor research. Enclosure of the tumor by the radiopaque eggshell and the small structural size only allows monitoring from above and challenges established imaging techniques. We report the eligibility of ultrasonography for repetitive visualization of tumor growth and vascularization in the CAM-assay. After tumor ingrowth, ultrasonography was repetitively performed in ovo using a commercial ultrasonographic scanner. Finally, the tumor was excised and histologically analyzed. Tumor growth and angiogenesis were successfully monitored and findings in ultrasonographic imaging significantly correlated with results obtained in histological analysis. Ultrasonography is cost efficient and widely available. Tumor imaging in ovo enables the longitudinal monitoring of tumoral development, yet allowing high quantitative output due to the CAM-assays simple and cheap methodology. Thus, this methodological novelty improves reproducibility in the field of in vivo tumor experimentation emphasizing the CAM-assay as an alternative to rodent-xenograft-models.

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Recent Advances in Automated Chromosome Image Analysis

Handbook of Research on Advanced Techniques in Diagnostic Imaging and Biomedical Applications ◽

10.4018/978-1-60566-314-2.ch020 ◽

2009 ◽

pp. 307-319

Author(s):

Petros S. Karvelis ◽

Dimitrios I. Fotiadis

Keyword(s):

Image Analysis ◽

Multispectral Imaging ◽

Digital Images ◽

Imaging Techniques ◽

Automatic Segmentation ◽

Chromosome Analysis ◽

Color Information ◽

Human Cytogenetics ◽

Improved Methods

Automated chromosome analysis is now becoming routine in most human cytogenetics laboratories. It involves both processing and analysis of digital images and has been developed because of the demandby cytogeneticists. Over the years, many techniques have been introduced for the automatic segmentation and classification of chromosome images, of which only a few are included in the available commercial systems. Today, advances in chromosome imaging techniques, especially in multispectral imaging, lead the way for the development of new and improved methods for the location, segmentation and classification of chromosome images by exploiting the color information. In this chapter the authors describe methods which have been already developed for automated chromosome analysis.

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Development of the Foramen Secundum in the Chick as Observed by Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091044 ◽

1976 ◽

Vol 34 ◽

pp. 212-213

Author(s):

M.J.C. Hendrix ◽

D.E. Morse

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Procaine Hydrochloride ◽

Cardiac Anomaly ◽

Chick Embryos ◽

Congenital Cardiac Anomaly ◽

Septal Defects ◽

Critical Point Drying ◽

Scanning Electron

Atrial septal defects are considered the most common congenital cardiac anomaly occurring in humans. In studying the normal sequential development of the atrial septum, chick embryos of the White Leghorn strain were prepared for scanning electron microscopy and the results were then extrapolated to the human heart. One-hundred-eighty chick embryos from 2 to 21 days of age were removed from their shells and immersed in cold cacodylate-buffered aldehyde fixative . Twenty-four embryos through the first week post-hatching were perfused in vivo using cold cacodylate-buffered aldehyde fixative with procaine hydrochloride. The hearts were immediately dissected free and remained in the fixative a minimum of 2 hours. In most cases, the lateral atrial walls were removed during this period. The tissues were then dehydrated using a series of ascending grades of ethanol; final dehydration of the tissues was achieved via the critical point drying method followed by sputter-coating with goldpalladium.

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