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Three-dimensional lithographically-defined organotypic tissue arrays for quantitative analysis of morphogenesis and neoplastic progression

Description: Here we describe a simple micromolding method to construct three-dimensional arrays of organotypic epithelial tissue structures that approximate in vivo histology. An elastomeric stamp containing an array of posts of defined geometry and spacing is used to mold microscale cavities into the surface of type I collagen gels. Epithelial cells are seeded into the cavities and covered with a second layer of collagen. The cells reorganize into hollow tissues corresponding to the geometry of the caviti… more
Date: February 13, 2008
Creator: Nelson, Celeste M.; Inman, Jamie L. & Bissell, Mina J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The mechanics of soft biological composites.

Description: Biological tissues are uniquely structured materials with technologically appealing properties. Soft tissues such as skin, are constructed from a composite of strong fibrils and fluid-like matrix components. This was the first coordinated experimental/modeling project at Sandia or in the open literature to consider the mechanics of micromechanically-based anisotropy and viscoelasticity of soft biological tissues. We have exploited and applied Sandia's expertise in experimentation and mechanics … more
Date: October 1, 2007
Creator: Nguyen, Thao D. (Sandia National Laboratories, Livermore, CA); Grazier, John Mark; Boyce, Brad Lee & Jones, Reese E. (Sandia National Laboratories, Livermore, CA)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effects of polar solvents on the fracture resistance of dentin: Role of water hydration

Description: Although healthy dentin is invariably hydrated in vivo, from a perspective of examining the mechanisms of fracture in dentin, it is interesting to consider the role of water hydration. Furthermore, it is feasible that exposure to certain polar solvents, e.g., those found in clinical adhesives, can induce dehydration. In the present study, in vitro deformation and fracture experiments, the latter involving a resistance-curve (R-curve) approach (i.e., toughness evolution with crack extension), we… more
Date: December 10, 2004
Creator: Ritchie, R. O.; Nalla, R. K.; Balooch, M.; Ager, J. W., III; Kruzic, J. J. & Kinney, J. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effect of Structural Modification on Second Harmonic Generation in Collagen

Description: The effects of structural perturbation on second harmonic generation in collagen were investigated. Type I collagen fascicles obtained from rat tails were structurally modified by increasing nonenzymatic cross-linking, by thermal denaturation, by collagenase digestion, or by dehydration. Changes in polarization dependence were observed in the dehydrated samples. Surprisingly, no changes in polarization dependence were observed in highly crosslinked samples, despite significant alterations in pa… more
Date: April 4, 2003
Creator: Stoller, P C; Reiser, K M; Celliers, P M & Rubenchik, A M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Modeling the coupled mechanics, transport, and growth processes in collagen tissues.

Description: The purpose of this project is to develop tools to model and simulate the processes of self-assembly and growth in biological systems from the molecular to the continuum length scales. The model biological system chosen for the study is the tendon fiber which is composed mainly of Type I collagen fibrils. The macroscopic processes of self-assembly and growth at the fiber scale arise from microscopic processes at the fibrillar and molecular length scales. At these nano-scopic length scales, we e… more
Date: November 1, 2006
Creator: Holdych, David J.; Nguyen, Thao D.; Klein, Patrick A.; in't Veld, Pieter J. & Stevens, Mark Jackson
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Estrogen and progesterone receptors have distinct roles in the establishment of the hyperplastic phenotype in PR-A transgenic mice

Description: Expression of the A and B forms of progesterone receptor (PR) in an appropriate ratio is critical for mammary development. Mammary glands of PR-A transgenic mice, carrying an additional A form of PR as a transgene, exhibit morphological features associated with the development of mammary tumors. Our objective was to determine the roles of estrogen (E) and progesterone (P) in the genesis of mammary hyperplasias/preneoplasias in PR-A transgenics. We subjected PR-A mice to hormonal treatments and … more
Date: May 11, 2009
Creator: Simian, Marina; Bissell, Mina J.; Barcellos-Hoff, Mary Helen & Shyamala, Gopalan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Mineralization of Synthetic Polymer Scaffolds: A Bottom-upApproach for the Development of Artificial Bone

Description: The controlled integration of organic and inorganic components confers natural bone with superior mechanical properties. Bone biogenesis is thought to occur by templated mineralization of hard apatite crystals by an elastic protein scaffold, a process we sought to emulate with synthetic biomimetic hydrogel polymers. Crosslinked polymethacrylamide and polymethacrylate hydrogels were functionalized with mineral-binding ligands and used to template the formation of hydroxyapatite. Strong adhesion … more
Date: September 27, 2004
Creator: Song, Jie; Viengkham, Malathong & Bertozzi, Carolyn R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Confocal Imaging of Biological Tissues Using Second Harmonic Generation

Description: A confocal microscopy imaging system was devised to selectively detect Second harmonic signals generated by biological tissues. Several types of biological tissues were examined using this imaging system, including human teeth, bovine blood vessels, and chicken skin. All these tissues generated strong second harmonic signals. There is considerable evidence that the source of these signals in tissue is collagen. Collagen, the predominant component of most tissues, is known to have second order n… more
Date: March 6, 2000
Creator: Kim, B. M.; Stoller, P.; Reiser, K.; Eichler, J.; Yan, M.; Rubenchik, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Second Order Non-linear Susceptibility of Collagen using Polarization Modulation and Phase-sensitive Detection

Description: The measurement of the second order nonlinear susceptibility of collagen in various biological tissues has potential applications in the detection of structural changes which are related to different pathological conditions. We investigate second harmonic generation in rat-tail tendon, a highly organized collagen structure consisting of parallel fibers. Using an electro-optic modulator and a quarter-wave plate, we modulate the linear polarization of an ultra-short pulse laser beam that is used … more
Date: March 3, 2001
Creator: Stoller, P.; Kim, B. M.; Rubenchik, A. M.; Reiser, K. M. & Da Silva, L. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Imaging Collagen Orientation Using Polarization-Modulated Second Harmonic Generation

Description: We use polarization-modulated second harmonic generation to image fiber orientation in collagen tissues, with an axial resolution of about 10 {micro}m and a transverse resolution of up to 1 {micro}m. A linearly polarized ultra-short pulse (200 fs) Ti:Sapphire laser beam is modulated using an electro-optic modulator and quarter-wave plate combination and focused onto a translation stage mounted sample using a microscope objective. The generated second harmonic light is collected using a photomul… more
Date: January 10, 2002
Creator: Stoller, P; Celliers, P M; Reiser, K M & Rubenchik, A M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Polarization-Modulated Second Harmonic Generation Microscopy in Collagen

Description: Collagen is a key structural protein in the body; several pathological conditions lead to changes in collagen. Among imaging modalities that can be used in vivo, second harmonic generation (SHG) microscopy has a key advantage: it provides {approx}1 {micro}m resolution information about collagen structure as a function of depth. A new technique--polarization-modulated SHG--is presented: it permits simultaneous measurement of collagen orientation, of a lower bound on the magnitude of the second o… more
Date: September 30, 2002
Creator: Stoller, P. C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Tenascin-X, Collagen, Elastin and the Ehlers-Danlos Syndrome

Description: Tenascin-X is an extracellular matrix protein initially identified because of its overlap with the human CYP21B gene. Because studies of gene and protein function of other tenascins had been poorly predictive of essential functions in vivo, we used a genetic approach that critically relied on an understanding of the genomic locus to uncover an association between inactivating tenascin-X mutations and novel recessive and dominant forms of Ehlers-Danlos syndrome. Tenascin-X provides the first exa… more
Date: August 31, 2005
Creator: Bristow, James; Carey, William & Schalkwijk, Joost
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nidogen-1 regulates laminin-1-dependent mammary-specific gene expression

Description: Nidogen-1 (entactin) acts as a bridge between the extracellular matrix molecules laminin-1 and type IV collagen, and thus participates in the assembly of basement membranes. To investigate the role of nidogen-1 in regulating cell-type-specific gene expression in mammary epithelium, we designed a culture microecosystem in which each component, including epithelial cells, mesenchymal cells, lactogenic hormones and extracellular matrix, could be controlled. We found that primary and established me… more
Date: February 2000
Creator: Pujuguet, Philippe; Simian, Marina; Liaw, Jane; Timpl, Rupert; Werb, Zena & Bissell, Mina J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

On the Increasing Fragility of Human Teeth with Age: ADeep-Ultraviolet Resonance Raman Study

Description: Ultraviolet resonance Raman spectroscopy (UVRRS) using 244nm excitation was used to investigate the impact of aging on humandentin. The intensity of a spectroscopic feature from the peptide bondsin the collagen increases with tissue age, similar to a finding reportedpreviously for human cortical bone.
Date: July 14, 2006
Creator: Ager, J. W., III; Nalla, R. K.; Balooch, G.; Kim, G.; Pugach, M.; Habelitz, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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