scholarly journals The Regulation of Growth in Developing, Homeostatic, and Regenerating Tetrapod Limbs: A Minireview

2022 ◽  
Vol 9 ◽  
Author(s):  
Kaylee M. Wells ◽  
Mary Baumel ◽  
Catherine D. McCusker
Keyword(s):  
Animal Models ◽  
Limb Bud ◽  
Long Bones ◽  
Final Size ◽  
Size And Shape ◽  
Regulation Of Growth

The size and shape of the tetrapod limb play central roles in their functionality and the overall physiology of the organism. In this minireview we will discuss observations on mutant animal models and humans, which show that the growth and final size of the limb is most impacted by factors that regulate either limb bud patterning or the elongation of the long bones. We will also apply the lessons that have been learned from embryos to how growth could be regulated in regenerating limb structures and outline the challenges that are unique to regenerating animals.

scholarly journals Dissecting human embryonic skeletal stem cell ontogeny by single-cell transcriptomic and functional analyses

Cell Research ◽  
2021 ◽  
Author(s):  
Jian He ◽  
Jing Yan ◽  
Jianfang Wang ◽  
Liangyu Zhao ◽  
Qian Xin ◽  
...  
Keyword(s):  
Single Cell ◽  
Progenitor Cells ◽  
Limb Bud ◽  
Cellular Heterogeneity ◽  
Transcriptional Networks ◽  
Marker Genes ◽  
Long Bones ◽  
Hematopoietic Stroma ◽  
Human Limb ◽  
Functional Analyses

AbstractHuman skeletal stem cells (SSCs) have been discovered in fetal and adult long bones. However, the spatiotemporal ontogeny of human embryonic SSCs during early skeletogenesis remains elusive. Here we map the transcriptional landscape of human limb buds and embryonic long bones at single-cell resolution to address this fundamental question. We found remarkable heterogeneity within human limb bud mesenchyme and epithelium, and aligned them along the proximal–distal and anterior–posterior axes using known marker genes. Osteo-chondrogenic progenitors first appeared in the core limb bud mesenchyme, which give rise to multiple populations of stem/progenitor cells in embryonic long bones undergoing endochondral ossification. Importantly, a perichondrial embryonic skeletal stem/progenitor cell (eSSPC) subset was identified, which could self-renew and generate the osteochondral lineage cells, but not adipocytes or hematopoietic stroma. eSSPCs are marked by the adhesion molecule CADM1 and highly enriched with FOXP1/2 transcriptional network. Interestingly, neural crest-derived cells with similar phenotypic markers and transcriptional networks were also found in the sagittal suture of human embryonic calvaria. Taken together, this study revealed the cellular heterogeneity and lineage hierarchy during human embryonic skeletogenesis, and identified distinct skeletal stem/progenitor cells that orchestrate endochondral and intramembranous ossification.

Establishment of an ABAQUS Model to Predict Final Size and Shape of a Molded Glass Lens

2008 ◽  
Author(s):  
Scott W. Gaylord ◽  
Balajee Ananthasayanam ◽  
Laeticia Petit ◽  
Vincent Blouin ◽  
Paul Joseph ◽  
...  
Keyword(s):  
Final Size ◽  
Size And Shape ◽  
Glass Lens ◽  
Abaqus Model

scholarly journals Zone of Polarizing Activity Regulatory Sequence Mutations/Duplications with Preaxial Polydactyly and Longitudinal Preaxial Ray Deficiency in the Phenotype: A Review of Human Cases, Animal Models, and Insights Regarding the Pathogenesis

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad M. Al-Qattan
Keyword(s):  
Developmental Biology ◽  
Animal Models ◽  
Sonic Hedgehog ◽  
Ectopic Expression ◽  
Point Mutations ◽  
Limb Bud ◽  
Regulatory Sequence ◽  
Preaxial Polydactyly ◽  
Zone Of Polarizing Activity

Clinicians and scientists interested in developmental biology have viewed preaxial polydactyly (PPD) and longitudinal preaxial ray deficiency (LPAD) as two different entities. Point mutations and duplications in the zone of polarizing activity regulatory sequence (ZRS) are associated with anterior ectopic expression of Sonic Hedgehog (SHH) in the limb bud and usually result in a PPD phenotype. However, some of these mutations/duplications also have LPAD in the phenotype. This unusual PPD-LPAD association in ZRS mutations/duplications has not been specifically reviewed in the literature. The author reviews this unusual entity and gives insights regarding its pathogenesis.

scholarly journals Shape-Evolution and Growth Mechanism of Fe3O4Polyhedrons

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Liqiao Chen ◽  
Qiang Zhou ◽  
Qingfeng Xiong ◽  
Wenlin Li ◽  
Jisong Liu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Mechanism ◽  
Nucleation And Growth ◽  
Low Energy ◽  
Growth Speed ◽  
Shape Evolution ◽  
Final Size ◽  
One Pot ◽  
Size And Shape ◽  
Spherical Crystals

The shape evolution of spinel-structured Fe3O4was systematically investigated using a one-pot solvothermal route. Using FeCl3·6H2O as the precursor, triangular and hexagonal plates, octahedrons, dodecahedrons, and spherical Fe3O4were obtained by selecting the adequate ration of NaOH, N2H4·H2O, Fe3+, and EDTA. The slow nucleation and growth rate favor the formation of low energy plate-like products, and the spherical crystals are obtained as the result of extremely fast nucleation and growth rate. It is also suggested that the generating rate of Fe(II) reduced from Fe(III) probably affects the growth speed along different facets, further influencing the final size and shape of the produced crystals.

Estimation of the size and shape of GH secretory bursts in healthy women using a physiological estradiol clamp and variable-waveform deconvolution model

2007 ◽  
Vol 293 (3) ◽  
pp. R1013-R1021 ◽  
Author(s):  
Johannes D. Veldhuis ◽  
Daniel M. Keenan ◽  
Cyril Y. Bowers
Keyword(s):  
Pulse Number ◽  
Elimination Kinetics ◽  
Size And Shape ◽  
Gh Secretion ◽  
Healthy Women ◽  
Estrogen Production ◽  
Mass Size ◽  
Time Required ◽  
Time Invariant ◽  
Regulation Of Growth

Because estrogen production and age are strong covariates, distinguishing their individual impact on hypothalamo-pituitary regulation of growth hormone (GH) output is difficult. In addition, at fixed elimination kinetics, systemic GH concentration patterns are controlled by three major signal types [GH-releasing hormone (GHRH), GH-releasing peptide (GHRP, ghrelin), and somatostatin (SS)] and by four dynamic mechanisms [the number, mass (size), and shape (waveform) of secretory bursts and basal (time invariant) GH secretion]. The present study introduces an investigative strategy comprising 1) imposition of an experimental estradiol clamp in pre- (PRE) and postmenopausal (POST) women; 2) stimulation of fasting GH secretion by each of GHRH, GHRP-2 (a ghrelin analog), and l-arginine (to putatively limit SSergic restraint); and 3) implementation of a flexible-waveform deconvolution model to estimate basal GH secretion simultaneously with the size and shape of secretory bursts, conditional on pulse number. The combined approach unveiled the following salient percent POST/PRE contrasts: 1) only 27% as much GH secreted in bursts during fasting ( P < 0.001); 2) markedly attenuated burstlike GH secretion in response to bolus GHRP-2 (29%), bolus GHRH (30%), l-arginine (37%), constant GHRP-2 (38%), and constant GHRH (42%) (age contrasts, 0.0016 ≤ P ≤ 0.027); and 3) a 160% prolongation and 32% abbreviation of the time required to achieve maximal GH secretion after injection of l-arginine and bolus GHRP-2, respectively (both, P < 0.001). Accordingly, age selectively determines both the size (amount) and shape (waveform) of GH secretory bursts in healthy women independently of the short-term estrogen milieu.

Characterization of Novolac Based Photoresists to Fabricate 3D Polymer Dome Features

2005 ◽  
Author(s):  
Sriram Muthukumar ◽  
Tom W. Miller ◽  
Balu Pathangey ◽  
Neha M. Patel ◽  
Charles D. Hill
Keyword(s):  
Thermal Characteristics ◽  
Analytical Techniques ◽  
Gas Chromatography Mass Spectrometry ◽  
Solid Loading ◽  
Wafer Level ◽  
Final Size ◽  
Free Standing ◽  
Dome Formation ◽  
Size And Shape ◽  
Solvent Type

Wafer level, 3D, free standing structures (e.g., domes or hemi-cylinders) can be fabricated using polymer dome features as sacrificial templates for MEMS and interconnect applications. Understanding the kinetics of dome formation and the material properties are essential for a robust and manufacturable process of controlling the size and shape of the photoresist features. In this paper, temporal and thermal characteristics of Novolac based photoresists are presented as a function of solid loading and solvent type using analytical techniques such as Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, hot stage microscopy, and Gas Chromatography/ Mass Spectrometry (GC/MS). The solid loading influences the thickness and processing ability of the resist. The solvent evaporation rate controls the final size and shape of the 3D polymer dome features. Solvent is the primary material lost during the dome formation and the onset of deformation is dependent on temperature and ramp rate.

Evidence for regulation of growth, size and pattern in the developing chick limb bud

Development ◽  
1981 ◽  
Vol 65 (Supplement) ◽  
pp. 129-150
Author(s):  
Dennis Summerbell
Keyword(s):  
Growth Rate ◽  
Cell Division ◽  
Irradiation Temperature ◽  
Limb Bud ◽  
Regulatory Mechanisms ◽  
Surgical Removal ◽  
Temperature Shock ◽  
X Irradiation ◽  
Zone Of Polarizing Activity ◽  
Regulation Of Growth

This paper examines the hypothesis that the developing chick limb bud has mechanisms for regulating the control of growth, size and pattern. The tests included: surgical removal of selected parts of the limb field, X-irradiation, temperature shock and the manipulation of known limb organizer regions (removal of the apical ectodermal ridge, or the addition of an extra zone of polarizing activity). The results strongly support the idea that there are regulatory mechanisms controlling both the pattern and the size of the limb and suggest that they involve regulation of the growth rate via control of cell division throughout the embryonic period. Possible mechanisms are discussed.

scholarly journals A comparison of the microarchitecture of lower limb long bones between some animal models and humans: a review

2013 ◽  
Vol 58 (No. 7) ◽  
pp. 339-351 ◽  
Author(s):  
VJ Cvetkovic ◽  
SJ Najman ◽  
JS Rajkovic ◽  
ALj Zabar ◽  
PJ Vasiljevic ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Animal Model ◽  
Animal Models ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Lower Limb ◽  
Bone Microarchitecture ◽  
Anatomical Location ◽  
Long Bones ◽  
Canal Diameter

Animal models are unavoidable and indispensable research tools in the fields of bone tissue engineering and experimental orthopaedics. The fact that there is not ideal animal model as well as the differences in the bone microarchitecture and physiology between animals and humans are complicate factors and make model implementation difficult. Therefore, the tendency should be directed towards extrapolation of the results from one animal model to another or from animal model to humans. So far, this is the first paper which provides an overview on the microarchitecture of lower limb long bones and discusses data related to osteon diameter, osteon canal diameter and their orientation, as well as intracortical canals and trabecular tissue microarchitecture in commonly used animal models compared to humans depending on age, gender and anatomical location of the bone. Understanding the differences between animal model and human bone microarchitecture should enable a more accurate extrapolation of experimental results from one animal model to another or from animal models to humans in the fields of bone tissue engineering and experimental orthopaedics. Also, this should be helpful in making decisions on which animal models are the most suitable for particular preclinical testing. &nbsp;

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