The origin and movement of the limb-bud epithelium and mesenchyme in the chick embryo as determined by radioautographic mapping

Development ◽  
1971 ◽  
Vol 25 (1) ◽  
pp. 85-96
Author(s):  
Glenn C. Rosenquist
Keyword(s):  
Primitive Streak ◽  
Limb Bud ◽  
Lateral Margin ◽  
Lateral Plate ◽  
Posterior Limb ◽  
Process Stage ◽  
The Future ◽  
Dorsal Portion ◽  
Definition Of ◽  
Area Pellucida

The origin of the limb-bud cells was determined by tracing the movements of [3H]thymidine-labelled grafts excised from late medium-streak to 5-somite stage chick embryos and transplanted to the epiblast, streak, and endoderm-mesoderm of similarly staged recipient embryos. Although exact definition of the prelimb areas was not possible because of the small number of grafts placed at each developmental stage, the study showed in general that at the late medium-streak stage the future limb-bud epithelium is in the epiblast (dorsal) layer near the lateral margin of the area pellucida. It moves medially toward the embryonic axis, just lateral to the premesoderm cells which will be invaginated at the primitive streak. With regression of the streak, the limb-bud epithelium moves relatively anteriorly into a position dorsal to the limb-bud mesoderm, beginning at least as early as the early head-fold stage. At the definitive-streak stage, the future limb-bud mesoderm is in the epiblast layer about halfway from the streak to the lateral margin of the area pellucida, at a level about halfway between the anterior and posterior ends of the streak. From this position the prelimb mesoderm migrates medially to the streak, and is invaginated into the mesoderm layer at a position about halfway between the anterior and posterior ends of the streak; after the head-process stage, it migrates anteriorly and laterally into the somatic layer of the lateral plate, ventral to the limb-bud epithelium. Mesoderm which will form the anterior limb-bud migrates anterior to mesoderm which will form the posterior limb-bud; mesoderm which will form the ventral portion of each limb-bud migrates posterolateral to mesoderm which will form the dorsal portion of each limb-bud.

The origin and movement of prelung cells in the chick embryo as determined by radioautographic mapping

Development ◽  
1970 ◽  
Vol 24 (3) ◽  
pp. 497-509
Author(s):  
Glenn C. Rosenquist
Keyword(s):  
Chick Embryo ◽  
Primitive Streak ◽  
Lateral Margin ◽  
Chick Embryos ◽  
Process Stage ◽  
Somite Stage ◽  
Dorsal Mesentery ◽  
Area Pellucida

The origin of the prelung cells was determined by tracing the movements of [3H]thymidinelabelled grafts excised from medium-streak to 4-somite stage chick embryos and transplanted to the epiblast, streak, and endoderm-mesoderm of similarly staged recipient embryos. At the medium-streak stage the prelung endoderm cells are in the anterior third of the primitive streak; they shortly begin to migrate anteriorly and laterally into the endoderm layer. They are folded into the gut beginning at about the 4-somite stage, and begin to reach their definitive position in the ventrolateral gut wall at the 10- to 16-somite stage. At the ± 22-somite stage the prelung endoderm begins to burrow into the overlying splanchnic layer of mesoderm, pushing the prelung mesoderm ahead of it. At the medium-streak stage the prelung mesoderm is in the epiblast (dorsal) layer about half-way to the lateral margin of the area pellucida on either side of the streak, at a level about half-way between the anterior and posterior ends of the streak. From this position the prelung mesoderm migrates medially to the streak and is invaginated into the mesoderm layer at a position about half-way between the anterior and posterior ends of the streak. As a section of the dorsal mesentery, it migrates anteriorly and laterally from the streak into the splanchnic mesoderm lateral to the somites. From the head process stage to the early somite stages, the prelung mesoderm is located posterior to the prelung endoderm. The prelung mesoderm continues to migrate with the splanchnic mesoderm into the mesentery dorsal to the heart, where it invests the prelung endoderm after the 16- to 19-somite stage. Beginning at about the 22-somite stage, the prelung endoderm penetrates the prelung mesoderm and the bilateral bronchi are formed.

The origin and movements of the hepatogenic cells in the chick embryo as determined by radioautographic mapping

Development ◽  
1971 ◽  
Vol 25 (1) ◽  
pp. 97-113
Author(s):  
Glenn C. Rosenquist
Keyword(s):  
Chick Embryo ◽  
Developmental Stage ◽  
Primitive Streak ◽  
Limb Bud ◽  
Chick Embryos ◽  
Lateral Plate Mesoderm ◽  
Lateral Plate ◽  
Somite Stage ◽  
Definition Of ◽  
Exact Definition

The origin of the prehepatic cells was determined by tracing the movements of [3H]thymidine-labelled grafts excised from medium-streak to 4-somite stage chick embryos and transplanted to the epiblast, streak and endoderm-mesoderm layer of similarly staged recipient embryos. Although exact definition of prehepatic areas was not possible because of the small number of grafts placed at each developmental stage, the study showed in general that at the medium-streak stage, the prehepatic endoderm cells are in the anterior third of the primitive streak; they shortly begin to migrate anteriorly and laterally into the endoderm layer ventral to the precardiac areas of mesoderm. They are in the yolk-sac endoderm at the 2–4-somite stage, and by the 15–17-somite stage are clustered at the anterior intestinal portal. At the 26-somite to early limb-bud stages, the anterior and posterior liver diverticula have formed from these endoderm cells, and some of the branches of the diverticula may have reached the prehepatic mesenchyme, where the two tissues have begun to form cords and sinuses. At the medium-streak stage, the prehepatic mesoderm is located slightly more than halfway from the anterior to the posterior end of the primitive streak. From this position it migrates anteriorly and laterally into the lateral plate mesoderm, and from the head-process to the 2–4-somite stage it is situated posterior to the prehepatic endoderm and posterior and lateral to the heart-forming portion of the splanchnic layer. By the 15–17-somite stage the prehepatic mesoderm has reached a position in the splanchnic layer of mesoderm which forms the dorsolateral wall of the sinus venosus. By the 26-somite to early limb-bud stage the hepatic diverticula have joined with the hepatic mesenchyme to form the rudimentary cords and sinuses of the liver.

Evidence that members of the Cut/Cux/CDP family may be involved in AER positioning and polarizing activity during chick limb development

Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5133-5144
Author(s):  
A.T. Tavares ◽  
T. Tsukui ◽  
J.C. Izpisua Belmonte
Keyword(s):  
Limb Development ◽  
Limb Bud ◽  
Wing Margin ◽  
Lateral Plate ◽  
Posterior Limb ◽  
Downstream Target ◽  
Notch Pathways ◽  
Specialized Region ◽  
Dorsoventral Boundary ◽  
Cycle Regulation

In vertebrates, the apical ectodermal ridge (AER) is a specialized epithelium localized at the dorsoventral boundary of the limb bud that regulates limb outgrowth. In Drosophila, the wing margin is also a specialized region located at the dorsoventral frontier of the wing imaginal disc. The wingless and Notch pathways have been implicated in positioning both the wing margin and the AER. One of the nuclear effectors of the Notch signal in the wing margin is the transcription factor cut. Here we report the identification of two chick homologues of the Cut/Cux/CDP family that are expressed in the developing limb bud. Chick cux1 is expressed in the ectoderm outside the AER, as well as around ridge-like structures induced by (β)-catenin, a downstream target of the Wnt pathway. cux1 overexpression in the chick limb results in scalloping of the AER and limb truncations, suggesting that Cux1 may have a role in limiting the position of the AER by preventing the ectodermal cells around it from differentiating into AER cells. The second molecule of the Cut family identified in this study, cux2, is expressed in the pre-limb lateral plate mesoderm, posterior limb bud and flank mesenchyme, a pattern reminiscent of the distribution of polarizing activity. The polarizing activity is determined by the ability of a certain region to induce digit duplications when grafted into the anterior margin of a host limb bud. Several manipulations of the chick limb bud show that cux2 expression is regulated by retinoic acid, Sonic hedgehog and the posterior AER. These results suggest that Cux2 may have a role in generating or mediating polarizing activity. Taking into account the probable involvement of Cut/Cux/CDP molecules in cell cycle regulation and differentiation, our results raise the hypothesis that chick Cux1 and Cux2 may act by modulating proliferation versus differentiation in the limb ectoderm and polarizing activity regions, respectively.

Developmental potency of the murine allantois

Development ◽  
1997 ◽  
Vol 124 (14) ◽  
pp. 2769-2780 ◽  
Author(s):  
K.M. Downs ◽  
C. Harmann
Keyword(s):  
Germ Line ◽  
Primitive Streak ◽  
Paraxial Mesoderm ◽  
Final Position ◽  
Lateral Plate Mesoderm ◽  
Lateral Plate ◽  
The Future ◽  
Fusion Junction ◽  
Tip Cells ◽  
Derivatives Of

The murine allantois is the future umbilical component of the placenta. The base of the allantois is also thought to contain the future germ line. We have examined the fate and developmental potency of cells within the murine allantois during gastrulation. lacZ-expressing headfold-stage allantoises (approximately 8.0 days postcoitum; dpc) were subdivided into three proximodistal regions and transplanted into three sites in synchronous non-transgenic host embryos: the primitive streak at the level of prospective paraxial mesoderm, the primitive streak at the level of lateral plate mesoderm, and the base of the allantois. After 23 hours in culture, operated conceptuses were examined histologically for contribution of donor allantoic cells to the conceptus. None of the allantoic regions contributed to paraxial mesoderm when placed into the fetus, but all three colonized the endothelium and adjacent mesenchyme of the dorsal aorta. The mid-region was most efficient at colonizing endothelium, whereas the base was the only allantoic region to exhibit relative pluripotency, colonizing several derivatives of all three primary germ layers. Differences in the state of differentiation along the proximodistal axis of the allantois were further borne out when the three allantoic regions were placed into the base of the allantois of host conceptuses. Striking differences were observed in final position along the proximodistal axis of the host allantois. Most grafted cells translocated distally from the base; however, basal donor allantoic cells translocated typically only as far as the host's mid-region, whereas donor allantoic tip cells typically returned to the tip, often colonizing the chorioallantoic fusion junction. Together, our data reveal that the headfold-stage allantois may contain a proximodistal gradient of differentiation, and raise intriguing questions about how this gradient was established and the role it plays in umbilical vasculogenesis.

Challenges of Fear Conditioning Research in the Age of RDoC

2017 ◽  
Vol 225 (3) ◽  
pp. 189-199 ◽  
Author(s):  
Tina B. Lonsdorf ◽  
Jan Richter
Keyword(s):  
Fear Conditioning ◽  
Clinical Diagnosis ◽  
Research Domain Criteria ◽  
Major Focus ◽  
The Future ◽  
Definition Of ◽  
Methodological Considerations ◽  
Research Domain

Abstract. As the criticism of the definition of the phenotype (i.e., clinical diagnosis) represents the major focus of the Research Domain Criteria (RDoC) initiative, it is somewhat surprising that discussions have not yet focused more on specific conceptual and procedural considerations of the suggested RDoC constructs, sub-constructs, and associated paradigms. We argue that we need more precise thinking as well as a conceptual and methodological discussion of RDoC domains and constructs, their interrelationships as well as their experimental operationalization and nomenclature. The present work is intended to start such a debate using fear conditioning as an example. Thereby, we aim to provide thought-provoking impulses on the role of fear conditioning in the age of RDoC as well as conceptual and methodological considerations and suggestions to guide RDoC-based fear conditioning research in the future.

ASO GUMBALO SEBAGAI INSPIRAS DALAM PENCIPTAAN SENI LUKIS

2018 ◽  
Vol 7 (2) ◽  
pp. 178
Author(s):  
Satri Yadi ◽  
Yuniarti Munaf ◽  
Dhasono Dhasono
Keyword(s):  
Design Phase ◽  
Symbolic Expression ◽  
Ethical Research ◽  
Process Stage ◽  
Form Processing ◽  
The Future ◽  
The Creation ◽  
Visual Strategies ◽  
Work Done ◽  
Exploration Phase

AbstrakAso Gumbalo dalam penciptaan karya seni lukis diilhami dari kehidupan pengembala yang menjadi inspirasi pencipta yang diungkap melalui media seni lukis dengan mengambil ide “Harapan Pengembala” (Aso Gumbalo). Harapan Gembala dapat diartikan sebagai keinginan, kecendrungan dan dorongan hati yang kuat terhadap sesuatu hal yang ingin direalisasikan untuk menjadikan seorang lebih baik dimasa depan. Pengekspresian ide cipta berangkat dari fenomena Aso Gumbalo yang pencipta ungkap dengan ekspresi simbolik kedalam penciptaan karya seni lukis. Metode penciptaan karya ini melalui tahapan yaitu; 1) Tahap eksplorasi adalah tahap pencarian ide-ide dengan melakukan riset emik dan etik untuk pembuatan karya, 2) Tahap perancangan yaitu tahap pembuatan purwarupa yang akan diwujudkan kedalam bentuk karya seni lukis, 3) Tahap proses garapan karya. Konsep dari penciptaan karya merupakan ekspresi simbolik dengan memanfaatkan idiom tradisi, ekspresi tersebut digambarkan pada perwujudan karya menggunakan strategi media dan strategi visual dengan menggunakan konsep pengolahan bentuk, yaitu disformasi dan transformasi dengan melakukan penggabungan beberapa teknik antara lain, teknik plakat, transparan, tekstur semu dan tekstur nyata. Aso Gumbalo sebagai inspirasi yang diungkapkan dalam bentuk karya seni lukis ekspresi simbolik. Karya-karya yang diciptakan pengkarya disajikan dalam bentukpameran.           Kata Kunci:aso gumbalo, ekspresi simbolik, seni lukis.   AbstractAsoGumbalo in the creation of painting works was inspired from the life of the shepherd who became the inspiration of the creator which revealed through the medium of painting by taking the idea of "Hope of the Shepherd" (AsoGumbalo). Shepherd Hope can be interpreted as a strong desire, inclination and encouragement towards something that wants to be realized to make someone better in the future. The expression of copyrighted ideas departs from the phenomenon of AsoGumbalo, which the creator expressed with a symbolic expression into the creation of painting. This method of creating works through several stages, namely; 1) The exploration phase is the stage of searching for ideas by conducting emic and ethical research for the production of works, 2) the design phase that is the prototype-making stage which will be realized in the form of painting, 3) the process stage of the work done. The concept of creation of works is a symbolic expression by utilizing traditional idioms, these expressions are depicted in the realization of the work using media strategies and visual strategies by using the concept of form processing, namely deformation and transformation by combining several techniques, such as plaque, transparent, pseudo-texture and real texture. AsoGumbalo as an inspiration expressed in the form of paintings of symbolic expression. works created by artists are presented in the form of exhibitions.  Keywords:asogumbalo, symbolic expression, painting.  

Neuroethics

2017 ◽  
Keyword(s):  
Brain Function ◽  
Ethical Issues ◽  
Wearable Technologies ◽  
Definition Of Death ◽  
Populations At Risk ◽  
The Future ◽  
Aging Adults ◽  
Definition Of ◽  
The Brain ◽  
New Criteria

We have new answers to how the brain works and tools which can now monitor and manipulate brain function. Rapid advances in neuroscience raise critical questions with which society must grapple. What new balances must be struck between diagnosis and prediction, and invasive and noninvasive interventions? Are new criteria needed for the clinical definition of death in cases where individuals are eligible for organ donation? How will new mobile and wearable technologies affect the future of growing children and aging adults? To what extent is society responsible for protecting populations at risk from environmental neurotoxins? As data from emerging technologies converge and are made available on public databases, what frameworks and policies will maximize benefits while ensuring privacy of health information? And how can people and communities with different values and perspectives be maximally engaged in these important questions? Neuroethics: Anticipating the Future is written by scholars from diverse disciplines—neurology and neuroscience, ethics and law, public health, sociology, and philosophy. With its forward-looking insights and considerations for the future, the book examines the most pressing current ethical issues.

scholarly journals Solar barycentric dynamics from a new solar-planetary ephemeris

2018 ◽  
Vol 615 ◽  
pp. A153 ◽  
Author(s):  
Rodolfo G. Cionco ◽  
Dmitry A. Pavlov
Keyword(s):  
High Precision ◽  
Orbital Motion ◽  
Giant Planets ◽  
Reference Plane ◽  
The Sun ◽  
The Future ◽  
Dynamical Parameters ◽  
Definition Of ◽  
Invariable Plane ◽  
Planetary Theories

Aims. The barycentric dynamics of the Sun has increasingly been attracting the attention of researchers from several fields, due to the idea that interactions between the Sun’s orbital motion and solar internal functioning could be possible. Existing high-precision ephemerides that have been used for that purpose do not include the effects of trans-Neptunian bodies, which cause a significant offset in the definition of the solar system’s barycentre. In addition, the majority of the dynamical parameters of the solar barycentric orbit are not routinely calculated according to these ephemerides or are not publicly available. Methods. We developed a special version of the IAA RAS lunar–solar–planetary ephemerides, EPM2017H, to cover the whole Holocene and 1 kyr into the future. We studied the basic and derived (e.g., orbital torque) barycentric dynamical quantities of the Sun for that time span. A harmonic analysis (which involves an application of VSOP2013 and TOP2013 planetary theories) was performed on these parameters to obtain a physics-based interpretation of the main periodicities present in the solar barycentric movement. Results. We present a high-precision solar barycentric orbit and derived dynamical parameters (using the solar system’s invariable plane as the reference plane), widely accessible for the whole Holocene and 1 kyr in the future. Several particularities and barycentric phenomena are presented and explained on dynamical bases. A comparison with the Jet Propulsion Laboratory DE431 ephemeris, whose main differences arise from the modelling of trans-Neptunian bodies, shows significant discrepancies in several parameters (i.e., not only limited to angular elements) related to the solar barycentric dynamics. In addition, we identify the main periodicities of the Sun’s barycentric movement and the main giant planets perturbations related to them.

Is Sicily the future of Russia? Private protection and the rise of the Russian Mafia

2001 ◽  
Vol 42 (1) ◽  
pp. 186-220 ◽  
Author(s):  
Federico Varese
Keyword(s):  
Soviet Union ◽  
Power System ◽  
Former Soviet Union ◽  
Soviet Power ◽  
The Caucasus ◽  
The Future ◽  
Private Protection ◽  
Definition Of

It is difficult to discuss a phenomenon when one does not know precisely what it is. This problem is particularly vexing in the case of the Mafia. It has been argued that ‘the need for a definition [of the Mafia] is crucial; not just for any definition with some degree of contingent empirical plausibility, but for a definition with some analytical clout’ (1). The word ‘Mafia’ itself has travelled far to distant lands, such as the former Soviet Union. For instance, according to Arkadii Vaksberg, Russian journalist and author of The Russian Mafia, the Mafia is ‘the entire soviet power-system, all its ideological, political, economical and administrative manifestations’ (2). In an article published in a magazine for British executives dealing with Russia, the label Mafiosi is used to lump together bureaucrats, smugglers from the Caucasus, the CPSU nomenklatura accused of embezzling state funds, the late British businessman Robert Maxwell and many others (3).

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