Relevant bibliographies by topics / Limb bud

Academic literature on the topic 'Limb bud'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Limb bud"

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Lee, Christopher T., Luoping Li, Norio Takamoto, James F. Martin, Francesco J. DeMayo, Ming-Jer Tsai, and Sophia Y. Tsai. "The Nuclear Orphan Receptor COUP-TFII Is Required for Limb and Skeletal Muscle Development." Molecular and Cellular Biology 24, no. 24 (December 15, 2004): 10835–43. http://dx.doi.org/10.1128/mcb.24.24.10835-10843.2004.

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ABSTRACT The nuclear orphan receptor COUP-TFII is widely expressed in multiple tissues and organs throughout embryonic development, suggesting that COUP-TFII is involved in multiple aspects of embryogenesis. Because of the early embryonic lethality of COUP-TFII knockout mice, the role of COUP-TFII during limb development has not been determined. COUP-TFII is expressed in lateral plate mesoderm of the early embryo prior to limb bud formation. In addition, COUP-TFII is also expressed in the somites and skeletal muscle precursors of the limbs. Therefore, in order to study the potential role of COUP-TFII in limb and skeletal muscle development, we bypassed the early embryonic lethality of the COUP-TFII mutant by using two methods. First, embryonic chimera analysis has revealed an obligatory role for COUP-TFII in limb bud outgrowth since mutant cells are unable to contribute to the distally growing limb mesenchyme. Second, we used a conditional-knockout approach to ablate COUP-TFII specifically in the limbs. Loss of COUP-TFII in the limbs leads to hypoplastic skeletal muscle development, as well as shorter limbs. Taken together, our results demonstrate that COUP-TFII plays an early role in limb bud outgrowth but not limb bud initiation. Also, COUP-TFII is required for appropriate development of the skeletal musculature of developing limbs.
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2

Carrington, J. L., and J. F. Fallon. "Initial limb budding is independent of apical ectodermal ridge activity; evidence from a limbless mutant." Development 104, no. 3 (November 1, 1988): 361–67. http://dx.doi.org/10.1242/dev.104.3.361.

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Outgrowth of normal chick limb bud mesoderm is dependent on the presence of a specialized epithelium called the apical ectodermal ridge. This ectodermal ridge is induced by the mesoderm at about the time of limb bud formation. The limbless mutation in the chick affects apical ectodermal ridge formation in the limb buds of homozygotes. The initial formation of the limb bud appears to be unaffected by the mutation but no ridge develops and further outgrowth, which is normally dependent on the ridge, does not take place. As a result, limbless chicks develop without limbs. In the present study, which utilized a pre-limb-bud recombinant technique, limbless mesoderm induced an apical ectodermal ridge in grafted normal flank ectoderm. However, at stages when normal flank ectoderm is capable of responding to ridge induction, limbless flank ectoderm did not form a ridge or promote outgrowth of a limb in response to normal presumptive wing bud mesoderm. We conclude from this that the limbless mutation affects the ability of the ectoderm to form a ridge. In addition, because the limbless ectoderm has no morphological ridge and no apparent ridge activity (i.e. it does not stabilize limb elements in stage-18 limb bud mesoderm), the limbless mutant demonstrates that the initial formation of the limb bud is independent of apical ectodermal ridge activity.
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Zuniga, A., and R. Zeller. "Gli3 (Xt) and formin (ld) participate in the positioning of the polarising region and control of posterior limb-bud identity." Development 126, no. 1 (January 1, 1999): 13–21. http://dx.doi.org/10.1242/dev.126.1.13.

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During initiation of limb-bud outgrowth in vertebrate embryos, the polarising region (limb-bud organizer) is established upon activation of the Sonic Hedgehog (SHH) signaling molecule at the posterior limb-bud margin. Another hallmark of establishing anteroposterior limb-bud identities is the colinear activation of HoxD genes located at the 5′ end of the cluster (5′HoxD genes). The unique and shared functions of Gli3 and formin in these determinative events were genetically analyzed using single and double homozygous Extra-toes (Xt; disrupting Gli3) and limb deformity (ld; disrupting formin) mouse embryos. Analysis of the limb skeletal phenotypes reveals genetic interaction of the two genes. In addition to loss of digit identity and varying degrees of polydactyly, proximal skeletal elements are severely shortened in Xt;ld double homozygous limbs. The underlying molecular defects affect both establishment of the polarising region and posterior limb-bud identity. In particular, the synergism between Gli3- and formin-mediated mesenchyme-AER interactions positions the SHH signaling center at the posterior limb-bud margin. The present study shows that establishment and positioning of the polarising region is regulated both by restriction of Shh through Gli3 and its positive feedback regulation through formin. Concurrently, Gli3 functions independently of formin during initial posterior nesting of 5′HoxD domains, whereas their subsequent distal restriction and anterior expansion depends on genetic interaction of Gli3 and formin.
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Ros, M. A., A. Lopez-Martinez, B. K. Simandl, C. Rodriguez, J. C. Izpisua Belmonte, R. Dahn, and J. F. Fallon. "The limb field mesoderm determines initial limb bud anteroposterior asymmetry and budding independent of sonic hedgehog or apical ectodermal gene expressions." Development 122, no. 8 (August 1, 1996): 2319–30. http://dx.doi.org/10.1242/dev.122.8.2319.

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We have analyzed the pattern of expression of several genes implicated in limb initiation and outgrowth using limbless chicken embryos. We demonstrate that the expressions of the apical ridge associated genes, Fgf-8, Fgf-4, Bmp-2 and Bmp-4, are undetectable in limbless limb bud ectoderm; however, FGF2 protein is present in the limb bud ectoderm. Shh expression is undetectable in limbless limb bud mesoderm. Nevertheless, limbless limb bud mesoderm shows polarization manifested by the asymmetric expression of Hoxd-11, −12 and −13, Wnt-5a and Bmp-4 genes. The posterior limbless limb bud mesoderm, although not actually expressing Shh, is competent to express it if supplied with exogenous FGF or transplanted to a normal apical ridge environment, providing further evidence of mesodermal asymmetry. Exogenous FGF applied to limbless limb buds permits further growth and determination of recognizable skeletal elements, without the development of an apical ridge. However, the cells competent to express Shh do so at reduced levels; nevertheless, Bmp-2 is then rapidly expressed in the posterior limbless mesoderm. limbless limb buds appear as bi-dorsal structures, as the entire limb bud ectoderm expresses Wnt-7a, a marker for dorsal limb bud ectoderm; the ectoderm fails to express En-1, a marker of ventral ectoderm. As expected, C-Lmx1, which is downstream of Wnt-7a, is expressed in the entire limbless limb bud mesoderm. We conclude that anteroposterior polarity is established in the initial limb bud prior to Shh expression, apical ridge gene expression or dorsal-ventral asymmetry. We propose that the initial pattern of gene expressions in the emergent limb bud is established by axial influences on the limb field. These permit the bud to emerge with asymmetric gene expression before Shh and the apical ridge appear. We report that expression of Fgf-8 by the limb ectoderm is not required for the initiation of the limb bud. The gene expressions in the pre-ridge limb bud mesoderm, as in the limb bud itself, are unstable without stimulation from the apical ridge and the polarizing region (Shh) after budding is initiated. We propose that the defect in limbless limb buds is the lack of a dorsal-ventral interface in the limb bud ectoderm where the apical ridge induction signal would be received and an apical ridge formed. These observations provide evidence for the hypothesis that the dorsal-ventral ectoderm interface is a precondition for apical ridge formation.
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Grieshammer, U., G. Minowada, J. M. Pisenti, U. K. Abbott, and G. R. Martin. "The chick limbless mutation causes abnormalities in limb bud dorsal-ventral patterning: implications for the mechanism of apical ridge formation." Development 122, no. 12 (December 1, 1996): 3851–61. http://dx.doi.org/10.1242/dev.122.12.3851.

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In chick embryos homozygous for the limbless mutation, limb bud outgrowth is initiated, but a morphologically distinct apical ridge does not develop and limbs do not form. Here we report the results of an analysis of gene expression in limbless mutant limb buds. Fgf4, Fgf8, Bmp2 and Msx2, genes that are expressed in the apical ridge of normal limb buds, are not expressed in the mutant limb bud ectoderm, providing molecular support for the hypothesis that limb development fails in the limbless embryo because of the inability of the ectoderm to form a functional ridge. Moreover, Fgf8 expression is not detected in the ectoderm of the prospective limb territory or the early limb bud of limbless embryos. Since the early stages of limb bud outgrowth occur normally in the mutant embryos, this indicates that FGF8 is not required to promote initial limb bud outgrowth. In the absence of FGF8, Shh is also not expressed in the mutant limb buds, although its expression can be induced by application of FGF8-soaked beads. These observations support the hypothesis that Fgf8 is required for the induction of Shh expression during normal limb development. Bmp2 expression was also not detected in mutant limb mesoderm, consistent with the hypothesis that SHH induces its expression. In contrast, SHH is not required for the induction of Hoxd11 or Hoxd13 expression, since expression of both these genes was detected in the mutant limb buds. Thus, some aspects of mesoderm A-P patterning can occur in the absence of SHH and factors normally expressed in the apical ridge. Intriguingly, mutant limbs rescued by local application of FGF displayed a dorsalized feather pattern. Furthermore, the expression of Wnt7a, Lmx1 and En1, genes involved in limb D-V patterning, was found to be abnormal in mutant limb buds. These data suggest that D-V patterning and apical ridge formation are linked, since they show that the limbless mutation affects both processes. We present a model that explains the potential link between D-V positional information and apical ridge formation, and discuss the possible function of the limbless gene in terms of this model.
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Scaal, M., A. Bonafede, V. Dathe, M. Sachs, G. Cann, B. Christ, and B. Brand-Saberi. "SF/HGF is a mediator between limb patterning and muscle development." Development 126, no. 21 (November 1, 1999): 4885–93. http://dx.doi.org/10.1242/dev.126.21.4885.

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Scatter factor/hepatocyte growth factor (SF/HGF) is known to be involved in the detachment of myogenic precursor cells from the lateral dermomyotomes and their subsequent migration into the newly formed limb buds. As yet, however, nothing has been known about the role of the persistent expression of SF/HGF in the limb bud mesenchyme during later stages of limb bud development. To test for a potential role of SF/HGF in early limb muscle patterning, we examined the regulation of SF/HGF expression in the limb bud as well as the influence of SF/HGF on direction control of myogenic precursor cells in limb bud mesenchyme. We demonstrate that SF/HGF expression is controlled by signals involved in limb bud patterning. In the absence of an apical ectodermal ridge (AER), no expression of SF/HGF in the limb bud is observed. However, FGF-2 application can rescue SF/HGF expression. Excision of the zone of polarizing activity (ZPA) results in ectopic and enhanced SF/HGF expression in the posterior limb bud mesenchyme. We could identify BMP-2 as a potential inhibitor of SF/HGF expression in the posterior limb bud mesenchyme. We further demonstrate that ZPA excision results in a shift of Pax-3-positive cells towards the posterior limb bud mesenchyme, indicating a role of the ZPA in positioning of the premuscle masses. Moreover, we present evidence that, in the limb bud mesenchyme, SF/HGF increases the motility of myogenic precursor cells and has a role in maintaining their undifferentiated state during migration. We present a model for a crucial role of SF/HGF during migration and early patterning of muscle precursor cells in the vertebrate limb.
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Chan, D. C., A. Wynshaw-Boris, and P. Leder. "Formin isoforms are differentially expressed in the mouse embryo and are required for normal expression of fgf-4 and shh in the limb bud." Development 121, no. 10 (October 1, 1995): 3151–62. http://dx.doi.org/10.1242/dev.121.10.3151.

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Mice homozygous for the recessive limb deformity (ld) mutation display both limb and renal defects. The limb defects, oligodactyly and syndactyly, have been traced to improper differentiation of the apical ectodermal ridge (AER) and shortening of the anteroposterior limb axis. The renal defects, usually aplasia, are thought to result from failure of ureteric bud outgrowth. Since the ld locus gives rise to multiple RNA isoforms encoding several different proteins (termed formins), we wished to understand their role in the formation of these organs. Therefore, we first examined the embryonic expression patterns of the four major ld mRNA isoforms. Isoforms I, II and III (all containing a basic amino terminus) are expressed in dorsal root ganglia, cranial ganglia and the developing kidney including the ureteric bud. Isoform IV (containing an acidic amino terminus) is expressed in the notochord, the somites, the apical ectodermal ridge (AER) of the limb bud and the developing kidney including the ureteric bud. Using a lacZ reporter assay in transgenic mice, we show that this differential expression of isoform IV results from distinct regulatory sequences upstream of its first exon. These expression patterns suggest that all four isoforms may be involved in ureteric bud outgrowth, while isoform IV may be involved in AER differentiation. To define further the developmental consequences of the ld limb defect, we analyzed the expression of a number of genes thought to play a role in limb development. Most significantly, we find that although the AERs of ld limb buds express several AER markers, they do not express detectable levels of fibroblast growth factor 4 (fgf-4), which has been proposed to be the AER signal to the mesoderm. Thus we conclude that one or more formins are necessary to initiate and/or maintain fgf-4 production in the distal limb. Since ld limbs form distal structures such as digits, we further conclude that while fgf-4 is capable of supporting distal limb outgrowth in manipulated limbs, it is not essential for distal outgrowth in normal limb development. In addition, ld limbs show a severe decrease in the expression of several mesodermal markers, including sonic hedgehog (shh), a marker for the polarizing region and Hoxd-12, a marker for posterior mesoderm. We propose that incomplete differentiation of the AER in ld limb buds leads to reduction of polarizing activity and defects along the anteroposterior axis.
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Thaller, C., and G. Eichele. "Characterization of retinoid metabolism in the developing chick limb bud." Development 103, no. 3 (July 1, 1988): 473–83. http://dx.doi.org/10.1242/dev.103.3.473.

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Retinoids (vitamin A derivatives) have been shown to have striking effects on developing and regenerating vertebrate limbs. In the developing chick limb, retinoic acid is a candidate morphogen that may coordinate the pattern of cellular differentiation along the anteroposterior limb axis. We describe a series of investigations of the metabolic pathway of retinoids in the chick limb bud system. To study retinoid metabolism in the bud, all-trans-[3H]retinol, all-trans-[3H]retinal and all-trans-[3H]retinoic acid were released into the posterior region of the limb anlage, the area that contains the zone of polarizing activity, a tissue possibly involved in limb pattern formation. We found that the locally applied [3H]retinol is primarily converted to [3H]retinal, [3H]retinoic acid and a yet unidentified metabolite. When [3H]retinal is locally applied, it is either oxidized to [3H]retinoic acid or reduced to [3H]retinol. In contrast, local delivery of retinoic acid to the bud yields neither retinal nor retinol nor the unknown metabolite. This flow of metabolites agrees with the biochemical pathway of retinoids that has previously been elucidated in a number of other animal systems. To find out whether metabolism takes place directly in the treated limb bud, we have compared the amount of [3H]retinoid present in each of the four limb anlagen following local treatment of the right wing bud. The data suggest that retinoid metabolism takes place mostly in the treated limb bud. This local metabolism could provide a simple mechanism to generate in a controlled fashion the biologically active all-trans-retinoic acid from its abundant biosynthetic precursor retinol. In addition, local metabolism supports the hypothesis that retinoids are local chemical mediators involved in pattern formation.
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Al-Musawi, Duha, and Hayder Mubarak. "MESENCHYMAL CELL DEATH IN MOUSE LIMB BUD AFTER THE ONSET OF PRIMARY MYOGENESIS." Iraqi Journal of Medical Sciences 16, no. 1 (March 31, 2018): 41–50. http://dx.doi.org/10.22578/ijms.16.1.7.

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Background: The vertebrate limb bud develops as an outgrowth of mesoderm, which forms all their elements (muscles, nerves, vessels, bone, cartilage, and tendon). Myogenic precursor cells are seen at E11.5 mouse embryo, when the first nerve fascicles begin to enter the limb. The first signs of musculature masses are seen at E12.5 in both fore and hind limb buds. Apoptosis or programmed cell death is essential in the development of the limbs. In vertebrate, the developing limb morphogenesis depends on the appropriate spatial and temporal balance between cell death and cell proliferation. Objective: To perform comprehensive analysis of the proximo-distal pattern of cell death, evaluated by (TUNEL test) in cross sections of mouse limbs during prenatal development after onset of primary myogenesis. Methods: Fifteen pregnant female mice (Musmusculus) were divided into three groups according to the days of pregnancy into day (14, 16 and 19), only two embryos were taken from each mouse. All the limb buds were involved in this study. Paraffin embedded histological cross-sections of the limb buds were prepared, histological staining (using H&E stain) and TUNEL test labeling were done. Assessment of the number of apoptotic cells in the limb bud mesenchyme was done by counting these cells. Results: The H&E stained sections of the limb buds showed less amounts of mesenchymal tissues in older embryos (day 19). The TUNEL stain showed active apoptotic changes at proximal parts of the limb buds at gestational day 19, while the distal parts of the limbs buds showed active apoptotic changes at the early days (day 14). The evaluation of TUNEL test reaction in the proximal regions showed statistical significant increase of apoptotic cells in day 19 compared to day 14 (p = 0.001 for both). The mean number of apoptotic cells in the proximal regions were statistically significant (p = 0.001) between day 16 and day 19. While the mean number of apoptotic cells of distal regions of the limb buds was higher at day 14 compared to that of day 16 and day 19. These differences between day 14 and day 16 were statistically significant and between day 16 and day 19 while statistically non-significant between day 14 and day 19. Comparison of mean number of apoptotic cells between proximal and distal regions in all the three groups showed a statistically significant higher mean number of apoptotic cells in the distal regions compared to proximal region (p = 0.001). The mean number of the apoptotic cells in both regions (proximal and distal) of the limb buds revealed statistically significant differences between day 16 and day 19 (p = 0.001). Conclusion: Apoptosis was higher in all parts of the developing limbs during day 19, and that could be associated with degenerative changes occurring at the apical ectodermal ridge. Moreover, apoptosis was higher in the distal part of the limb bud and this may be due to more differentiation of the distal parts than in the proximal part of the limb bud. Keywords: Development, limb bud, mouse, embryo, TUNEL, apoptosis, mesenchyme Citation: Al-Musawi DML, Mubarak HJ. Mesenchymal Cell death in mouse limb bud after the onset of primary myogenesis. Iraqi JMS. 2018; Vol. 16(1): 41-50. doi: 10.22578/IJMS.16.1.7
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Gibson-Brown, J. J., S. I. Agulnik, L. M. Silver, L. Niswander, and V. E. Papaioannou. "Involvement of T-box genes Tbx2-Tbx5 in vertebrate limb specification and development." Development 125, no. 13 (July 1, 1998): 2499–509. http://dx.doi.org/10.1242/dev.125.13.2499.

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We have recently shown in mice that four members of the T-box family of transcription factors (Tbx2-Tbx5) are expressed in developing limb buds, and that expression of two of these genes, Tbx4 and Tbx5, is primarily restricted to the developing hindlimbs and forelimbs, respectively. In this report, we investigate the role of these genes in limb specification and development, using the chick as a model system. We induced the formation of ectopic limbs in the flank of chick embryos to examine the relationship between the identity of the limb-specific T-box genes being expressed and the identity of limb structures that subsequently develop. We found that, whereas bud regions expressing Tbx4 developed characteristic leg structures, regions expressing Tbx5 developed characteristic wing features. In addition, heterotopic grafts of limb mesenchyme (wing bud into leg bud, and vice versa), which are known to retain the identity of the donor tissue after transplantation, retained autonomous expression of the appropriate, limb-specific T-box gene, with no evidence of regulation by the host bud. Thus there is a direct relationship between the identity of the structures that develop in normal, ectopic and recombinant limbs, and the identity of the T-box gene(s) being expressed. To investigate the regulation of T-box gene expression during limb development, we employed several other embryological manipulations. By surgically removing the apical ectodermal ridge (AER) from either wing or leg buds, we found that, in contrast to all other genes implicated in the patterning of developing appendages, maintenance of T-box gene expression is not dependent on the continued provision of signals from the AER or the zone of polarizing activity (ZPA). By generating an ectopic ZPA, by grafting a sonic hedgehog (SHH)-expressing cell pellet under the anterior AER, we found that Tbx2 expression can lie downstream of SHH. Finally, by grafting a SHH-expressing cell pellet to the anterior margin of a bud from which the AER had been removed, we found that Tbx2 may be a direct, short-range target of SHH. Our findings suggest that these genes are intimately involved in limb development and the specification of limb identity, and a new model for the evolution of vertebrate appendages is proposed.
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Dissertations / Theses on the topic "Limb bud"

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Vargesson, Neil Andrew. "Cell fate and signalling in chick limb bud development." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287476.

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Ali-Khan, Sarah Esme. "Molecular mechanisms of Vitamin A-induced limb defects in the mid-organogenesis-stage mouse limb bud." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102475.

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The goal of this thesis was to move toward defining the molecular mechanism(s) of Vitamin A-induced limb malformations. Vitamin A and its biologically active metabolites, the retinoids, are potent limb teratogens, inducing reductive defects, preceded by decreased chondrogenesis and upregulated apoptosis. To target the origins of these effects, we focused initially on characterizing the pathway of Vitamin A-induced apoptosis. Our first objective was to identify mediators of the degradation and commitment phases of this process. We show dose-dependent activation of the effector caspase, caspase-3, and increased mitochondrial cytochrome-c release after treatment. The next objective was to determine whether these changes were receptor-mediated. Both pan-RAR (BMS 189453) and, surprisingly, pan-RXR (HX603) antagonists were able to ameliorate Vitamin A-induced limb malformations and apoptosis, indicating both receptor subtypes are important mediators of these processes. Interestingly, exposure to either antagonist alone also upregulated apoptosis. Each compound induced a specific, reproducible pattern of limb bud apoptosis, reiterating the fact that proper regulation of this process is crucial for normal limb morphology. Our final objective was to identify genes that may be responsible for the apoptosis and other pathologies observed after retinoid exposure. Vitamin A treatment significantly upregulated 81 genes, including key limb development signaling molecules, oncogenes, extracellular matrix/cell adhesion molecules, and transcriptional regulators such as Id3, Snai1, Hes1 and Eya2. To link these expression changes to teratogenic outcome, the response of these 4 genes was assessed after Vitamin A exposure, and after limb bud rescue with BMS 189453 and HX603; expression levels were correlated with limb malformations. Pathway analysis of the significantly upregulated genes reveals that many that are associated with cell-cycle, apoptosis and chondrogenesis are functionally linked. Moreover, members of these cascades cross-talk with one another, indicating that retinoids affect multiple cellular processes in a coordinated fashion to induce their teratogenic effects. Collectively, these studies have advanced our understanding of Vitamin A-mediated apoptotic pathways. In addition, we have proposed several mechanisms for retinoid-induced limb malformations, identified novel retinoid targets, and revealed multiple avenues for future research.
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Miura, Takashi. "Mechanism of chondrogenic pattern formation in mouse limb bud micromass culture." Kyoto University, 2000. http://hdl.handle.net/2433/157002.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・課程博士
博士(医学)
甲第8234号
医博第2190号
新制||医||730(附属図書館)
UT51-2000-F138
京都大学大学院医学研究科生理系専攻
(主査)教授 開 祐示, 教授 井手 千束, 教授 塩田 浩平
学位規則第4条第1項該当
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Marr, Misti Lane. "DISCOVERY OF PROTEINS SECRETED BY CHICK LIMB BUD CELLS IN RESPONSE TO MECHANICAL LOADING." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-12082009-140639/.

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The global objective of this research was to identify the proteins secreted by stem cells in response to mechanical stress. Since it has been shown in previous studies that conditioned medium from compressed chick limb bud cells cultured in alginate can initiate chondrogenesis in non-compressed cells, it was hypothesized that the conditioned medium contains valuable growth/differentiation factors. Due to cartilage?s limited capacity for repair, factors that stimulate stem-cell mediated regeneration are highly sought. To discern these proteins, conditioned medium was collected from cyclically compressed stage 23/24 chick limb buds suspended in alginate. The proteins were extracted, separated by 2-D gel electrophoresis, and evaluated by mass spectroscopy. While a few regulators of chondrogenesis were observed, such as FGF receptor, actin, and IP3 receptor, many potential peptides were not found in the database. However, this study showed that ascertaining proteins produced by chondrocytes in response to mechanical stimulation should be pursued
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Allen, John C. "FGF4 Induced Wnt5a Gradient in the Limb Bud Mediates Mesenchymal Cell Directed Migration and Division." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4309.

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The AER has a vital role in directing embryonic limb development. Several models have been developed that attempt to explain how the AER directs limb development, but none of them are fully supported by existing data. I provide evidence that FGFs secreted from the AER induce a gradient of Wnt5a. I also demonstrate that limb mesenchyme grows toward increasing concentrations of Wnt5a. We hypothesize that the changing shape of the AER is critical for patterning the limb along the proximal to distal axis. To better understand the pathway through which Wnt5a elicits its effects, we have performed various genetic studies. We demonstrate that Wnt5a does not signal via the Wnt/β-catenin pathway. However, we show that Wnt5a mutants share many common defects with Vangl2 mutants suggesting that Wnt5a signals through the Wnt/planar cell polarity (PCP) pathway.
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Qiu, Qingchao. "TGF-β, WNT, AND FGF SIGNALING PATHWAYS DURING AXOLOTL TAIL REGENERATION AND FORELIMB BUD DEVELOPMENT." UKnowledge, 2019. https://uknowledge.uky.edu/neurobio_etds/24.

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Tgf-β, Wnt, and Fgf signaling pathways are required for many developmental processes. Here, I investigated the requirement of these signaling pathways during tail regeneration and limb development in the Mexican axolotl (Ambystoma mexicanum). Using small chemical inhibitors during tail regeneration, I found that the Tgf-β signaling pathway was required from 0-24 and 48-72 hours post tail amputation (hpa), the Wnt signaling pathway was required from 0-120 hpa, and the Fgf signaling pathway was required from 0-12hpa. Tgf-β1 was upregulated after amputation and thus may mediate Tgf-β signaling pathway during tail regeneration. Both Smad-mediated and non-Smad mediated Tgf-β signaling were activated as early as 1hpa. Smad-mediated Tgf-β signaling via activated pSmad2 and pSmad3, and via phosphorylated Erk and Akt. Two different Tgf-β signaling pathway inhibitors, SB505124 and Naringenin, differentially regulated pSmad2, pSmad3, p-Erk, and p-Akt, while SB505124 and Naringenin both inhibited tail regeneration; only SB505124 reduced cell proliferation. Wnt/β-Catenin signaling was increased and was enhanced by Wnt-C59. Disruption of the Wnt signaling pathway directly or indirectly activated Erk and Akt signaling. Disruption of the Fgf signaling pathway decreased p-Erk and increased p-Akt. All three signaling pathways affected cell proliferation and mitosis during tail regeneration. The Wnt pathway inhibitor Wnt-C59 prevented forelimb bud outgrowth. The critical window for Wnt signaling regulating forelimb bud outgrowth was approximately developmental stage 40-42. Wnt signaling ligand Wnt3a and tight junction protein Zo-1 were expressed in the epidermis of the forelimb bud and both were down-regulated by Wnt-C59. Moreover, both Wnt and Fgf signaling pathways affected cell proliferation and mitosis of mesodermal cells during forelimb bud outgrowth. Overall, my results show that Tgf-β, Wnt, and Fgf signaling pathways are required for axolotl tail regeneration. All three pathways affect Erk and Akt signaling and guide cell proliferation and mitosis. The Wnt signaling pathway is required for forelimb bud outgrowth, and it appears to regulate expression of Wnt3a and Zo1, and control cell proliferation and mitosis of mesodermal cells underlying the forelimb epidermis. These data enrich understanding of signaling network dynamics that underlie tissue regeneration and vertebrate limb development.
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Mella, Sébastien. "Histoire évolutive des facteurs de transcription de la famille COE : expression comparée au cours de la morphogenèse de l'aile de drosophile et des membres de tétrapodes et évolution de leur structure génomique chez les bilatériens." Toulouse 3, 2004. http://www.theses.fr/2004TOU30294.

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La thèse analyse deux aspects de l'évolution de la famille de facteur de transcription COE. Le premier aspect concerne le recrutement et la fonction de ces gènes dans les processus de morphogenèse, des ailes de drosophile et des membres de tétrapodes. Malgré les évidentes différences morphologiques de ces structures, l'acquisition de leur polarité selon l'axe antéro-postérieure (A-P) implique la même voie de signalisation : la voie de signalisation Hedgehog/Sonic-Hedgehog (Hh/SHH). Lors de la morphogenèse de l'aile de drosophile, collier a un rôle clé en tant que médiateur de la signalisation Hh. Dans cette thèse, la question de la conservation d'un rôle similaire pour les gènes orthologues à collier chez les vertébrés a été posée. L'analyse du patron d'expression des gènes coe dans les bourgeons de membre de poulet et de souris sauvages et dans des contextes de gain et de perte de fonction de la signalisation SHH a amené deux conclusions majeures; i) les gènes coe semblent être recrutés de manière différente entre l'aile de drosophile et le bourgeon de membre de tétrapode, ii) les gènes coe apparaissent comme les premiers marqueurs connus de deux sous-domaines du tissu conjonctif, les ligaments et les gaines protectrices des tendons. Pour analyser la fonction de ces gènes au cours dans la formation des membres de tétrapodes, une stratégie utlisant une protéine dominante-négative (DN) a été développée. Les propriétés biochimiques de la protéine DN ont été determinées in vivo en utilisant des drosophiles transgénique où les effets du DN ont pu être comparés aux phénotypes de perte de fonction de collier. Le deuxième aspect de l'évolution de cette famille gènique concerne l'évolution de leur structure génomique. La comparaison des séquences génomiques, disponibles pour différents phyla appartenant au groupe des animaux bilatériens, a permis de révèler une forte concervation de la structure Exon/intron de ces gènes génomique. Cette analyse a, de plus, conduit à proposer un nouveau model pour la formation de motifs protéiques par accrétion de domaines par duplication exonique
The thesis focuses on the evolution of coe transcription factor family. Behind the obvious morphological differences between a Drosophila wing and a tetrapod limb, the same signalling pathway, namely the Hedgehog/Sonic-hedgehog (HH/Shh) pathway, sets up the antero-posterior polarity. During Drosophila wing morphogenesis, collier is a key mediator of the Hh signalisation. In a first approach, the coe genes expression in tetrapod limb bud development and its relationship with Shh signalisation has been analysed. The analysis of coe expression in wild type mouse and chick developing limb bud revealed these genes as first known markers for ligaments and tendon protecting-casing. The analysis of coe genes expression in several mouse mutant strains, coupled with graft experiments in chick limb buds, strongly suggest that the molecular pathway involving Collier in the Drosophila wing is not conserved in the tetrapod limb. To determine the function of coe genes during tetrapod limb morphogenesis, a strategy based on the contruction of a Dominant-Negative COE protein (COE-DN) has been undertaken. The biochemical characteristics of the COE-DN has been determined in vivo, using transgenic flies, in which controlled expression of this COE-DN can be compared with the phenotype of collier null mutation
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Hardy, Adrian Paul. "Development of reaggregated chick limb buds." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338891.

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Thorn, Rebecca Emily. "Metric number theory : the good and the bad." Thesis, Queen Mary, University of London, 2005. http://qmro.qmul.ac.uk/xmlui/handle/123456789/28568.

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Each aspect of this thesis is motivated by the recent paper of Beresnevich, Dickinson and Velani (BDV03]. Let 'ljJ be a real, positive, decreasing function i.e. an approximation function. Their paper considers a general lim sup set A( 'ljJ), within a compact metric measure space (0, d, m), consisting of points that sit in infinitely many balls each centred at an element ROt of a countable set and of radius 'I/J(130) where 130 is a 'weight' assigned to each ROt. The classical set of 'I/J-well approximable numbers is the basic example. For the set A('ljJ) , [BDV03] achieves m-measure and Hausdorff measure laws analogous to the classical theorems of Khintchine and Jarnik. Our first results obtain an application of these metric laws to the set of 'ljJ-well approximable numbers with restricted rationals, previously considered by Harman (Har88c]. Next, we consider a generalisation of the set of badly approximable numbers, Bad. For an approximation function p, a point x of a compact metric space is in a general set Bad(p) if, loosely speaking, x 'avoids' any ball centred at an element ROt of a countable set and of radius c p(I3Ot) for c = c(x) a constant. In view of Jarnik's 1928 result that dim Bad = 1, we aim to show the general set Bad(p) has maximal Hausdorff dimension. Finally, we extend the theory of (BDV03] by constructing a general lim sup set dependent on two approximation functions, A('ljJll'ljJ2)' We state a measure theorem for this set analogous to Khintchine's (1926a) theorem for the Lebesgue measure of the set of ('l/Jl, 1/12)-well approximable pairs in R2. We also remark on the set's Hausdorff dimension.
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Lesnicar-Pucko, Gaja 1981. "Cellular mechanisms behind vertebrate limp outgrowth." Doctoral thesis, Universitat Pompeu Fabra, 2014. http://hdl.handle.net/10803/346928.

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In this work we use a novel in vivo imaging technique and cell behaviour analysis to investigate the cellular basis of limb bud elongation. Recently, it has become clear that oriented cell activities must be involved in this process and cell migration and cell division orientation stood out as the most probable candidates. Here, we present a comprehensive study with a focus on cell orientations and active cell behaviour in the developing chick limb bud. We find that cells orient themselves toward the closest ectoderm and divide along their long axis and that, although the gross cell movement shows distal bias, active migration orientation of single cells seems to be random. As our results do not support the distalward migration and oriented division theory, we propose cell intercalation as the most probable cell behaviour involved in limb morphogenesis. We validate this new hypothesis with a Cellular Potts computer model that theoretically confirms our assumption
En aquest projecte utilitzem una nova tècnica de microscòpia in vivo, així com l’anàlisi del comportament cel.lular per tal d’investigar les bases cel.lulars de l’elongació de l’extremitat durant el desenvolupament embrionari. Investigacions recents clarament indiquen que activitats cel.lulars orientades estan involucrades en aquest procès, i d’entre elles la migració cel.lular i la divisió cel.lular orientada semblen les candidates més probables. Aquí presentem un estudi exhaustiu enfocat principalment en l’orientació cel.lular i el comportament cel.lular actiu durant el desenvolupament de l’extremitat del pollet. Trobem que les cel.lules s’orienten cap a l’ectodermi més proper i es divideixen al llarg a l’axis més llarg, així com veiem que, malgrat que el moviment cel.lular global mostra una tendència distal, la migració activa de cel.lules individuals sembla ser aleatòria. Donat que els nostres resultats no recolzen la teoria d’una migració distalment orientada amb divisió cel.lular orientada, proposem la intercal.lació cel.lular com al comportament cel.lular més probable involucrat en la morfogènesi de l’extremitat. Aquesta nova hipòtesi es veu validada mitjançant un model computacional de Cellular Potts que confirma el nostre supòsit
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Books on the topic "Limb bud"

1

Services, Dearborn Environmental Consulting. Treatability of wastewaters from high CaO and CaSO4 content FBC wastes. Ottawa, Ont., Canada: Environment Canada, 1986.

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Barembaum, Meyer. Isolation of cDNA clones expressed in differentiating mesenchyme during early limb bud development. 1993.

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Malko, Andrei. Characterization of the mouse limb bud cell culture model to study the role of calreticulin in chondrogenesis. 2007.

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Bensmaia, Sliman J. Biohybrid touch interfaces. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0053.

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This chapter on biohybrid touch interfaces discusses the importance of touch in everyday life, namely in object manipulation, embodiment, and emotional communication. It then describes approaches to restore touch for individuals who have lost a limb or who have upper spinal cord injuries (SCIs) and thus have lost sensation from their limbs. One promising approach to restoring sensorimotor function in these patients is to fit them with robotic prostheses. For these limbs to be clinically viable, however, the patients must not only be able to control movements of the limb but also be able to receive sensory feedback about the consequences of the movements. Touch can be restored by interfacing with the peripheral nerve or with the brain and each approach offers promise but also faces challenges.
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Kenyon, Sherrilyn. Bad Attitude Lib/E. Urban Audiobooks, 2018.

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Bosch, Pseudonymous, and Aaron Landon. Bad News Lib/E. Little, Brown Young Readers, 2017.

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Bosch, Pseudonymous. Bad Magic Lib/E. Hachette Book Group, 2014.

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Oliver, Tess, Anna Hart, Mason Lloyd, and C. J. Bloom. Stone Cold Bad Lib/E. Tantor Audio, 2015.

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Hudson, Benjamin J., and Deborah M. Eastwood. Congenital upper limb anomalies. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199550647.003.013011.

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♦ Anomalies are common but often minor and of little functional concern♦ Often associated with other manifestations that are of greater clinical significance♦ A knowledge of embryological development allows a better understanding of the clinical picture and informs management plans.
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Monster under the Bed: Band 11/Lime. HarperCollins Publishers Limited, 2010.

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Book chapters on the topic "Limb bud"

1

Theiler, Karl. "Closure of Posterior Neuropore; Hind Limb Bud and Tail Bud." In The House Mouse, 60–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-88418-4_19.

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Arostegui, Martin, and T. Michael Underhill. "Murine Limb Bud Organ Cultures for Studying Musculoskeletal Development." In Methods in Molecular Biology, 115–37. New York, NY: Springer US, 2020. http://dx.doi.org/10.1007/978-1-0716-1028-2_8.

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Ueda, Shogo, Takayuki Suzuki, and Mikiko Tanaka. "Transgene Introduction into the Chick Limb Bud by Electroporation." In Avian and Reptilian Developmental Biology, 203–8. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7216-6_13.

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Stainton, Holly, and Matthew Towers. "Polarizing Region Tissue Grafting in the Chick Embryo Limb Bud." In Methods in Molecular Biology, 143–53. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-8772-6_8.

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Hornbruch, Amata. "The Pathway of Polarizing Activity from Hensen’s Node To the Wing Bud in the Chick Embryo." In Developmental Patterning of the Vertebrate Limb, 165–70. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3310-8_24.

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Papageorgiou, S., D. Venieratos, and E. Vamvassakis. "Supernumerary Limbs Developing after Small Angle Dislocations of the Limb Bud of the Newt." In Recent Trends in Regeneration Research, 391–98. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4684-9057-2_37.

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Hurle, J. M., D. Macias, Y. Gañan, M. A. Ros, and M. A. Fernandez-Teran. "The Interdigital Spaces of the Chick Leg Bud as a Model for Analysing Limb Morphogenesis and Cell Differentiation." In Developmental Patterning of the Vertebrate Limb, 249–59. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3310-8_34.

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Critchlow, Matthew A., and J. Richard Hinchliffe. "Special Properties of the AER/Mesenchyme Interface in the Chick Wing Bud: Analysis of ECM Molecules and Integrin Receptors." In Developmental Patterning of the Vertebrate Limb, 189–202. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3310-8_27.

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Paradis, France-Hélène, Han Yan, Chunwei Huang, and Barbara F. Hales. "The Murine Limb Bud in Culture as an In Vitro Teratogenicity Test System." In Methods in Molecular Biology, 73–91. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9182-2_6.

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Paradis, France-Hélène, Chunwei Huang, and Barbara F. Hales. "The Murine Limb Bud in Culture as an In Vitro Teratogenicity Test System." In Methods in Molecular Biology, 197–213. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-867-2_12.

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Conference papers on the topic "Limb bud"

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Zhou, Yongchun, Junye Liu, Guozhen Guo, Kangchu Li, Jie Zhang, Jiaxing Zhou, Heming Wu, Xia Miao, Yurong Tao, and Dandan Sun. "Effects of EMP on Mouse Embryonic Limb Bud Cells." In 2006 4th Asia-Pacific Conference on Environmental Electromagnetics. IEEE, 2006. http://dx.doi.org/10.1109/ceem.2006.257921.

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Jun Wen, Jun Liu, Kimberly Lau, Haijiao Liu, Sevan Hopyan, and Yu Sun. "Automated micro-aspiration of mouse embryo limb bud tissue." In 2015 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 2015. http://dx.doi.org/10.1109/icra.2015.7139559.

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Huang, Alice H., Spencer S. Watson, and Ronen Schweitzer. "Lineage Tracing Reveals a New Model for Tendon Growth and Elongation During Development." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80915.

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Tendons are dense, fibrous tissues connecting muscle to bone, and their primary function is to transmit muscle forces to the appropriate skeletal elements, thereby enabling movement. In the limb, flexion and extension of the hand (autopod) and wrist are controlled by long tendons that insert into muscles in the arm (zeugopod) [1]. Although tendons are critically important in mediating joint movement, the cellular and molecular events underlying tendon formation remain largely unknown. Using the transcription factor Scleraxis (Scx), which labels all tendon progenitors, we previously showed that in the mouse limb bud, Scx-expressing tendon progenitors are first induced in the mesenchyme underneath the ectoderm at E10.5; at E12.5, progenitors are loosely organized between the cartilage condensations and developing muscles, condensing to form distinct tendons by E13.5 [2]. By E14.5, limb tendon patterning is largely complete, with continued elongation and deposition of matrix from this stage onward.
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Briegel, K., and K. Ashad-Bishop. "Abstract P4-05-01: Limb-Bud-and-Heart (LBH), a novel WNT effector in promoting basal-like breast cancer." In Abstracts: 2018 San Antonio Breast Cancer Symposium; December 4-8, 2018; San Antonio, Texas. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.sabcs18-p4-05-01.

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Deng, Mingming, Ruoxi Yu, Zhi Li, Xiaofang Che, Huicong Song, Ximing Wang, Zhe Zhang, et al. "Abstract 1550: Limb-bud and heart inhibits the proliferation and metastasis of human lung adenocarcinoma cells and predicts survival outcome." In Proceedings: AACR Annual Meeting 2018; April 14-18, 2018; Chicago, IL. American Association for Cancer Research, 2018. http://dx.doi.org/10.1158/1538-7445.am2018-1550.

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Houston, Vern L., Carl P. Mason, Luigi Arena, Gangming Luo, Aaron C. Beattie, MaryAnne Garbarini, and Chaiya Thongpop. "Experimental Assessment and FEA Prediction of the Effects of Prosthetic Socket Geometry on Transtibial Amputee Residual Limb Circulation." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23093.

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Abstract Eighty plus percent of all lower limb amputations performed in the United States each year result from complications of peripheral vascular disease (PVD) [1]. PVD amputees’ vascular systems are significantly compromised and can withstand little extraneous insult. Clinical studies have shown that ill-fitting prosthetic sockets, and/or excessive prosthetics loads can traumatize amputees’ residual limb (RL) tissues [2]. Unfortunately, there are no decisive clinical measures currently available that can be used to ensure prosthesis geometry and applied prosthetics loads are safe and will not compromise limb circulation and cause tissue injury. Minus egregious symptoms of ischemic pain and tissue trauma, it is commonly assumed that the tissue stresses and strains caused by differences between RL and prosthetic socket geometries, and from prosthetics loads incurred during stance and gait, have minimal effect upon RL tissue circulation and health. The objective of this study was to investigate the validity of this assumption by quantitatively measuring the effects prosthetic socket design geometry and applied loads have on transtibial amputee RL tissue circulation, and to determine if tissue circulation sensitivities to variations in socket design were sufficient to enable optimization of prosthesis design parameters.
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Sarin, Vineet K., William R. Pratt, and S. David Stulberg. "Repeatability of a Computer-Aided Optical Tracking System for Total Knee Replacement Surgery." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23080.

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Abstract The success of total knee replacement surgery depends critically on the restoration of limb alignment and on proper implant positioning [1]. Even with contemporary mechanical alignment instrumentation, errors in alignment correction and implant positioning do occur [2–5]. To improve upon the accuracy of conventional mechanical instrumentation, computer-aided navigation systems have been developed for total knee replacement surgery. Clinical studies have demonstrated that use of these systems for knee replacement surgery can lead to improved limb alignment and implant positioning [6–9]. While such systems have been shown to be clinically effective, their overall accuracy and repeatability in clinical use appears to be highly technique dependent [10]. The inherent repeatability (precision) of such systems has not been closely investigated.
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Ostadabbas, Sarah, Maziyar Baran Pouyan, Mehrdad Nourani, and Nasser Kehtarnavaz. "In-bed posture classification and limb identification." In 2014 IEEE Biomedical Circuits and Systems Conference (BioCAS). IEEE, 2014. http://dx.doi.org/10.1109/biocas.2014.6981663.

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Margulis, W., F. C. Garcia, E. N. Hering, I. C. S. Carvalho, B. Lesche, and F. Laurell. "Creating a second order nonlinearity and a waveguide in soft glasses by poling." In Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/bgppf.1997.btud.1.

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Soft glasses, such as soda lime are the often used in waveguide fabrication by ion exchange. They are also cheap, readily available, and are potentially a base material for active components in fiber-to-the-home systems. Therefore, waveguide modulators based on poled soda lime glass are of great interest. In this work we demonstrate that it is possible to induce a large second-order optical nonlinearity in soda lime and borosilicate glass with the electro-thermal poling procedure described by Myers et al1. We also demonstrate a scheme based on poling to record single-mode waveguides in soda lime.
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Russell, Donald L., and Chad E. English. "An Equivalent Linkage Model for Understanding Stiffness Effects of Biarticular Muscles." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23057.

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Abstract The purpose of this paper is to describe a method for aiding in the intuitive understanding of the effects of bi-articular muscles on the stiffness of a limb. In particular, a kinematic analysis of a mechanical model of a human arm is performed. The results are manipulated into a form that makes evident a mathematical decomposition of the kinematics. This gives rise to a mechanical analog to the decomposition: an equivalent four-bar linkage with single-joint muscles. Further insight is gained as the equivalent linkage provides an intuitive direction associated with each set of muscles.
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Reports on the topic "Limb bud"

1

Xing, Ying, Hongping Liu, Yifei Wang, and Tiancai Wen. Effects of acupuncture on pain in diabetic peripheral neuropathy: a systematic review and meta-analysis of randomized controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, September 2022. http://dx.doi.org/10.37766/inplasy2022.9.0019.

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Review question / Objective: The purpose of this review is to determine the efficacy and safety of acupuncture on diabetic peripheral neuropathy (DPN) pain compared with analgesics or sham acupuncture.Randomized controlled trials are the only types of studies included in this review. Condition being studied: Diabetic peripheral neuropathy (DPN) is a common complication of type 1 and 2 diabetes. It is also the main cause of lower limb amputation and disability in patients with diabetes. Epidemiological evidence shows that up to 50% of patients with diabetes developed neuropathy during their long-term course of disease. The cause of DPN is not completely clear, but older age, longer diabetic duration and worse postprandial glucose control has been proved to be closely related to DPN. Distal symmetric polyneuropathy is the most typical manifestation of DPN, and about 10% to 30% of the affected patients may experience symptoms of neuropathic pain. Pain can be described as burning pain, electrical or stabbing sensations, parasthesiae, hyperasthesiae, and deep aching pain of the feet and lower limbs at night. This irreversible and unbearable pain greatly affects patients' sleep and quality of life.
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Scholl, Lynn, Daniel Oviedo, Marco Innao, and Lauramaría Pedraza. Do Bus Rapid Transit Systems Improve Accessibility to Jobs?: The Case of Lima, Peru. Inter-American Development Bank, December 2018. http://dx.doi.org/10.18235/0001525.

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Scholl, Lynn, Daniel Martínez, Oscar A. Mitnik, Daniel Oviedo, and Patricia Yáñez-Pagans. A Rapid Road to Employment?: The Impacts of a Bus Rapid Transit System in Lima. Inter-American Development Bank, December 2018. http://dx.doi.org/10.18235/0001527.

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Lee, Sang-Kwun, T. C. Keener, J. L. Cook, and Soon Jai Khang. Attrition and changes in size distribution of lime sorbents during fluidization in a circulating fluidized bed absorber. Double quarterly report, January 1--August 31, 1993. Office of Scientific and Technical Information (OSTI), December 1993. http://dx.doi.org/10.2172/10177732.

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Oviedo, Daniel, Lisa Corsetto, Lynn Scholl, Cheryl Gray, and César P. Bouillon. Documento de enfoque: Evaluación de los efectos de los sistemas de BRT apoyados por el BID en la movilidad y el acceso para los pobres en Cali y Lima. Inter-American Development Bank, March 2016. http://dx.doi.org/10.18235/0000282.

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Shani, Moshe, and C. P. Emerson. Genetic Manipulation of the Adipose Tissue via Transgenesis. United States Department of Agriculture, April 1995. http://dx.doi.org/10.32747/1995.7604929.bard.

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The long term goal of this study was to reduce caloric and fat content of beef and other red meats by means of genetic modification of the animal such that fat would not be accumulated. This was attempted by introducing into the germ line myogenic regulatory genes that would convert fat tissue to skeletal muscle. We first determined the consequences of ectopic expression of the myogenic regulatory gene MyoD1. It was found that deregulation of MyoD1 did not result in ectopic skeletal muscle formation but rather led to embryonic lethalities, probably due to its role in the control of the cell cycle. This indicated that MyoD1 should be placed under stringent control to allow survival. Embryonic lethalities were also observed when the regulatory elements of the adipose-specific gene adipsin directed the expression of MyoD1 or myogenin cDNAs, suggesting that these sequences are probably not strong enough to confer tissue specificity. To determine the specificity of the control elements of another fat specific gene (adipocyte protein 2-aP2), we fused them to the bacterial b-galactosidase reporter gene and established stable transgenic strains. The expression of the reporter gene in none of the strains was adipose specific. Each strain displayed a unique pattern of expression in various cell lineages. Most exciting results were obtained in a transgenic strain in which cells migrating from the ventro-lateral edge of the dermomyotome of developing somites to populate the limb buds with myoblasts were specifically stained for lacZ. Since the control sequences of the adipsin or aP2 genes did not confer fat specificity in transgenic mice we have taken both molecular and genetic approaches as an initial effort to identify genes important in the conversion of a multipotential cell such as C3H10T1/2 cell to adipoblast. Several novel adipocyte cell lines have been established that differ in the expression of transcription factors of the C/EBP family known to be markers for adipocyte differentiation. These studies revealed that one of the genetic programming changes which occur during 10T1/2 conversion from multipotential cell to a committed adipoblast is the ability to linduce C/EBPa gene expression. It is expected that further analysis of this gene would identify elements which regulate this lineage-specific expression. Such elements might be good candidates in future attempts to convert adipoblasts to skeletal muscle cells in vivo.
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Perez-Vincent, Santiago M., and Enrique Carreras. Domestic Violence Reporting during the COVID-19 Pandemic: Evidence from Latin America. Inter-American Development Bank, October 2021. http://dx.doi.org/10.18235/0003744.

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This article examines changes in the frequency and characteristics of domestic violence reports after the start of the pandemic and the imposition of mobility restrictions in six Latin American countries. The study uses three types of data sources: calls to domestic violence hotlines (for the City of Buenos Aires in Argentina, Colombia, and Peru); calls to emergency lines (for Ecuador, Lima in Peru, and Costa Rica); and police/legal complaints (for Colombia, Ecuador, and Uruguay). Data through June 2020 shows that the pandemic's impact on domestic violence reports varied significantly across countries, periods, types of violence, and reporting channels. Calls to domestic violence hotlines soared, but calls to emergency lines and police complaints fell (especially in the first weeks of the pandemic). Significantly distinct patterns are observed between reports of psychological and physical violence, and non-cohabitant and cohabitant violence. These patterns are consistent with the pandemic changing the relative incidence of different types of violence and altering the perceived costs of reporting them through alternative channels. Increases in calls to domestic violence hotlines suggest that this channel was best suited to respond to victims' needs during the pandemic. In turn, the drop in legal complaints and calls to comprehensive emergency lines are consistent with an increase in the perceived (relative) cost of using these channels. The findings reveal how the pandemic altered domestic violence victims' demand for institutional help and highlight the relevance of domestic violence hotlines as an accessible and valuable service.
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Chriscoe, Mackenzie, Rowan Lockwood, Justin Tweet, and Vincent Santucci. Colonial National Historical Park: Paleontological resource inventory (public version). National Park Service, February 2022. http://dx.doi.org/10.36967/nrr-2291851.

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Colonial National Historical Park (COLO) in eastern Virginia was established for its historical significance, but significant paleontological resources are also found within its boundaries. The bluffs around Yorktown are composed of sedimentary rocks and deposits of the Yorktown Formation, a marine unit deposited approximately 4.9 to 2.8 million years ago. When the Yorktown Formation was being deposited, the shallow seas were populated by many species of invertebrates, vertebrates, and micro-organisms which have left body fossils and trace fossils behind. Corals, bryozoans, bivalves, gastropods, scaphopods, worms, crabs, ostracodes, echinoids, sharks, bony fishes, whales, and others were abundant. People have long known about the fossils of the Yorktown area. Beginning in the British colonial era, fossiliferous deposits were used to make lime and construct roads, while more consolidated intervals furnished building stone. Large shells were used as plates and dippers. Collection of specimens for study began in the late 17th century, before they were even recognized as fossils. The oldest image of a fossil from North America is of a typical Yorktown Formation shell now known as Chesapecten jeffersonius, probably collected from the Yorktown area and very likely from within what is now COLO. Fossil shells were observed by participants of the 1781 siege of Yorktown, and the landmark known as “Cornwallis Cave” is carved into rock made of shell fragments. Scientific description of Yorktown Formation fossils began in the early 19th century. At least 25 fossil species have been named from specimens known to have been discovered within COLO boundaries, and at least another 96 have been named from specimens potentially discovered within COLO, but with insufficient locality information to be certain. At least a dozen external repositories and probably many more have fossils collected from lands now within COLO, but again limited locality information makes it difficult to be sure. This paleontological resource inventory is the first of its kind for Colonial National Historical Park (COLO). Although COLO fossils have been studied as part of the Northeast Coastal Barrier Network (NCBN; Tweet et al. 2014) and, to a lesser extent, as part of a thematic inventory of caves (Santucci et al. 2001), the park had not received a comprehensive paleontological inventory before this report. This inventory allows for a deeper understanding of the park’s paleontological resources and compiles information from historical papers as well as recently completed field work. In summer 2020, researchers went into the field and collected eight bulk samples from three different localities within COLO. These samples will be added to COLO’s museum collections, making their overall collection more robust. In the future, these samples may be used for educational purposes, both for the general public and for employees of the park.
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9

Applebaum, Shalom W., Lawrence I. Gilbert, and Daniel Segal. Biochemical and Molecular Analysis of Juvenile Hormone Synthesis and its Regulation in the Mediterranean Fruit Fly (Ceratitis capitata). United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7570564.bard.

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Original Objectives and revisions: (1) "To determine the biosynthetic pathway of JHB3 in the adult C. capitata CA in order to establish parameters for the future choice and synthesis of suitable inhibitors". Modified: to determine the pattern of FR-7 biosynthesis during normal reproductive maturation, and identify enzymes potentially involved in its synthesis. (2) "To correlate allatal epoxidase activity to the biosynthesis of JHB3 at different stages of reproductive maturation/vitellogenesis and evaluate the hypothesis that a specific JH-epoxidase may be rate limiting". Modified: to study the effects of epoxidase inhibitors on the pattern of allatal JH biosynthesis in vitro and on female reproduction in vive. (3) "To probe and clone the gene homologous to ap from C. capitata, determine its exon-intron organization, sequence it and demonstrate its spatial and temporal expression in larvae, pupae and adults." The "Medfly" (Ceratitis capitata) is a serious polyphagous fruit pest, widely distributed in subtropical regions. Damage is caused by oviposition and subsequent development of larvae. JH's are dominant gonadotropic factors in insects. In the higher Diptera, to which the Medfly belongs, JHB3 is a major homolog. It comprises 95% of the total JH produced in vitro in D. melanogaster, with JH-III found as a minor component. The biosynthesis of both JH-III and JHB3 is dependent on epoxidation of double bonds in the JH molecule. The specificity of such epoxidases is unknown. The male accessory gland D. melanogaster produces a Sex Peptide, transferred to the female during copulation. SP reduces female receptivity while activating specific JH biosynthesis in vitro and inducing oviposition in vive. It also reduces pheromone production and activates CA of the moth Helicoverpa armigera. In a previous study, mutants of the apterous (ap) gene of D. melanogaster were analyzed. This gene induces previteilogenic arrest which can be rescued by external application of JH. Considerable progress has been made in recombinant DNA technology of the Medfly. When fully operative, it might be possible to effectively transfer D. melanogaster endocrine gene-lesions into the Medfly as a strategy for their genetic control. A marked heterogeneity in the pattern of JH homologs produced by Medfly CA was observed. Contrary to the anticipated biosynthesis of JHB;, significant amounts of an unknown JH-like compound, of unknown structure and provisionally termed FR-7, were produced, in addition to significant amounts of JH-III and JHB3. Inhibitors of monooxygenases, devised for their effects on ecdysteroid biosynthesis, affect Medfly JH biosynthesis but do not reduce egg deposition. FR-7 was isolated from incubation media of Medfly CA and examined by various MS procedures, but its structure is not yet resolved. MS analysis is being done in collaboration with Professor R.R.W. Rickards of the Australian National University in Canberra, Australia. A homologue of the ap gene of D. melanogaster exists in the Medfly. LIM domains and the homeo-domain, important for the function of the D. melanogaster ap gene, are conserved here too. Attempts to clone the complete gene were unsuccessful. Due to the complexity of JH homologs, presence of related FR-7 in the biosynthetic products of Medfly CA and lack of reduction in eggs deposited in the presence of monooxygenase inhibitors, inhibition of epoxidases is not a feasible alternative to control Medfly reproduction, and raises questions which cannot be resolved within the current dogma of hormonal control of reproduction in Diptera. The Medfly ap gene has similar domains to the D. melanogaster ap gene. Although mutant ap genes are involved in JH deficiency, ap is a questionable candidate for an endocrine lesion, especially since the D. melanogoster gene functions is a transcription factor.
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