The mechanisms that control lens refractive index and life-long lens transparency remain ***-crystallins,with chaperone-like activity,are presumably essential for establishing and maintaining lens transparency and hig...
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The mechanisms that control lens refractive index and life-long lens transparency remain ***-crystallins,with chaperone-like activity,are presumably essential for establishing and maintaining lens transparency and high refractive *** have studied three mouseαA-crystallin point mutations,one dominant mutation,αA-Y118D,and two
Metacarpophalangeal (MCP) joint proximal bone-cartilage specimens from the fourth digit were collected from repetitively flexed and non-flexed (control) paws of four New Zealand White rabbits. The specimens were cryo-...
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ISBN:
(纸本)9781605608525
Metacarpophalangeal (MCP) joint proximal bone-cartilage specimens from the fourth digit were collected from repetitively flexed and non-flexed (control) paws of four New Zealand White rabbits. The specimens were cryo-fractured to reveal a sagittal cut containing the cartilage zones of different collagen microstructure. Nanoindentation, Fourier Transform infrared microspectroscopic imaging (FTIRMI), and histology were performed on a region of interest (ROI) ∼400 microns wide and through the thickness of the cartilage with two goals in mind: (1) to examine the effect of collagen network structure (random in the mid zone versus organized in the deep zone) on the biomechanical and biochemical properties of cartilage;and (2) to understand the changes in these properties due to physical forces. We found that zone microstructure significantly affected the measurement of the local relaxed modulus measured by nanoindentation. The deep zone had a higher modulus than the mid zone (Wilcoxon paired test, p
Metacarpophalangeal (MCP) joint proximal bone-cartilage specimens from the fourth digit were collected from repetitively flexed and non-flexed (control) paws of four New Zealand White rabbits. The specimens were cryo-...
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Metacarpophalangeal (MCP) joint proximal bone-cartilage specimens from the fourth digit were collected from repetitively flexed and non-flexed (control) paws of four New Zealand White rabbits. The specimens were cryo-fractured to reveal a sagittal cut containing the cartilage zones of different collagen microstructure. Nanoindentation, Fourier Transform infrared microspectroscopic imaging (FTIRMI), and histology were performed on a region of interest (ROI) ∼400 microns wide and through the thickness of the cartilage with two goals in mind: (1) to examine the effect of collagen network structure (random in the mid zone versus organized in the deep zone) on the biomechanical and biochemical properties of cartilage; and (2) to understand the changes in these properties due to physical forces. We found that zone microstructure significantly affected the measurement of the local relaxed modulus measured by nanoindentation. The deep zone had a higher modulus than the mid zone (Wilcoxon paired test, p<0.05). We also found that flexion significantly decreased the proteoglycan content in both the mid and deep zones (Wilcoxon paired test, p<0.05), suggesting indirect repetitive loading in the rabbit paw can be damaging to the joint via down regulating proteoglycan synthesis in the mid and deep zone cartilage. This is the first study to simultaneously report the local zone-specific mechanical and biochemical properties in the rabbit joint flexion model.
Vaso-occlusion in sickle cell disease is fundamentally biophysical in nature, involving a complex set of cellular interactions. Originally attributed solely to the entrapment of abnormally rigid sickle red cells (RBCs...
Vaso-occlusion in sickle cell disease is fundamentally biophysical in nature, involving a complex set of cellular interactions. Originally attributed solely to the entrapment of abnormally rigid sickle red cells (RBCs) in the microcirculation, this process is now known to involve the decreased deformability of white blood cells (WBCs) and increased endothelial adhesion to different cell types (sickle RBCs, reticulocytes, WBCs, platelets). These biophysical interactions, which are also mediated biochemically by a variety of soluble factors (coagulation proteins, inflammatory mediators, reactive oxygen species, free hemoglobin, etc.), then ultimately lead to microvascular obstruction. However, in vitro experimental approaches that measure the vaso-occlusive properties of sickle blood cells have been unable to separate the contributions of decreased cell deformability and cell-cell adhesion in a single assay. Historically, cell deformability is measured using techniques such as micropipette aspiration, micropore filtration, and ektacytometry, whereas adhesive interactions between the endothelium, blood cells, and soluble factors are assessed using endothelial-lined flow chamber assays. No existing technique effectively evaluates both cell deformability and cell adhesion simultaneously, which is required to comprehensively study sickle cell vaso-occlusion. In the current study, we present an “endothelialized” microfluidic system that simultaneously integrates cell deformability and cell adhesion under physiologic microvascular flow conditions to investigate the underlying biophysical mechanisms of sickle cell vaso-occlusion. Briefly, a layer of human umbilical vein endothelial cells (HUVECs) was cultured along the inner walls of microfabricated microchannels made of the biocompatible and optically transparent polymer polydimethylsiloxane, or PDMS (Figure). Standard lab-on-chip photolithography techniques were utilized to design and create the microchannels, which geomet
This paper reports the development of a simple biophysical flow cytometer for quantification of blood cell deformability. Using the cytometer, comprised of a microfluidic PDMS device and image analysis software, we ca...
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Fibronectin is patterned on silicone rubber surfaces in arrays of 2pm diameter dots using contact removal method. Cells are cultured on the patterned surface and their migration and the structure of actin cytoskeleton...
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We used microfabricated topographical guidance to manipulate the organization of a single cell cytoskeleton, and to probe a cell from multiple directions to study the molecular mechanisms regulating the coordination p...
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A novel injection method is developed that utilizes a thermally switchable oligonucleotide affinity capture gel to mediate the concentration, purification and injection of double-stranded DNA for quantitative microchi...
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