Publications by authors named "Hibbard L"

Fibroblast growth factor 23 (FGF23) via its coreceptor αKlotho (KL) provides critical control of phosphate metabolism, which is altered in both rare and very common syndromes. However, the spatial-temporal mechanisms dictating kidney FGF23 functions remain poorly understood. Thus, developing approaches to modify specific FGF23-dictated pathways has proven problematic.

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Covalent hydrogel networks suffer from a stiffness-toughness conflict, where increased crosslinking density enhances the modulus of the material but also leads to embrittlement and diminished extensibility. Recently, strategies have been developed to form highly entangled hydrogels, colloquially referred to as tanglemers, by optimizing polymerization conditions to maximize the density and length of polymer chains and minimize the crosslinker concentration. It is challenging to assess entanglements in crosslinked networks beyond approximating their theoretical contribution to mechanical properties; thus, in this work, we synthesize and characterize polyacrylamide tanglemers using a photolabile crosslinker, which allows for direct assessment of covalent trapping of entanglements under tension.

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Hydrogels are often synthesized through photoinitiated step-, chain-, and mixed-mode polymerizations, generating diverse network topologies and resultant material properties that depend on the underlying network connectivity. While many photocrosslinking reactions are available, few afford controllable connectivity of the hydrogel network. Herein, a versatile photochemical strategy is introduced for tuning the structure of poly(ethylene glycol) (PEG) hydrogels using macromolecular monomers functionalized with maleimide and styrene moieties.

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Unlabelled: FGF23 via its coreceptor αKlotho (KL) provides critical control of phosphate metabolism, which is altered in rare and very common syndromes, however the spatial-temporal mechanisms dictating renal FGF23 functions remain poorly understood. Thus, developing approaches to modify specific FGF23-dictated pathways has proven problematic. Herein, wild type mice were injected with rFGF23 for 1, 4 and 12h and renal FGF23 bioactivity was determined at single cell resolution.

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Background: Pulmonary hypertension (PH) represents an important phenotype in heart failure with preserved ejection fraction (HFpEF). However, management of PH-HFpEF is challenging because mechanisms involved in the regulation of PH-HFpEF remain unclear.

Methods: We used a mass spectrometry-based comparative plasma proteomics approach as a sensitive and comprehensive hypothesis-generating discovery technique to profile proteins in patients with PH-HFpEF and control subjects.

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Granular biomaterials have found widespread applications in tissue engineering, in part because of their inherent porosity, tunable properties, injectability, and 3D printability. However, the assembly of granular hydrogels typically relies on spherical microparticles and more complex particle geometries have been limited in scope, often requiring templating of individual microgels by microfluidics or in-mold polymerization. Here, we use dithiolane-functionalized synthetic macromolecules to fabricate photopolymerized microgels via batch emulsion, and then harness the dynamic disulfide crosslinks to rearrange the network.

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Introduction: Due to a lack of spatial-temporal resolution at the single cell level, the etiologies of the bone dysfunction caused by diseases such as normal aging, osteoporosis, and the metabolic bone disease associated with chronic kidney disease (CKD) remain largely unknown.

Methods: To this end, flow cytometry and scRNAseq were performed on long bone cells from Sost-cre/Ai9 mice, and pure osteolineage transcriptomes were identified, including novel osteocyte-specific gene sets.

Results: Clustering analysis isolated osteoblast precursors that expressed , , and , and a mature osteoblast population defined by , , and .

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. To develop and evaluate a deep learning based fast volumetric modulated arc therapy (VMAT) plan generation method for prostate radiotherapy..

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Best-practices pedagogy in science, technology, engineering, and mathematics (STEM) aims for inclusive excellence that fosters student persistence. This paper describes principles of inclusivity across 11 primarily undergraduate institutions designated as Capstone Awardees in Howard Hughes Medical Institute's (HHMI) 2012 competition. The Capstones represent a range of institutional missions, student profiles, and geographical locations.

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Purpose: To accurately reconstruct, and interactively reshape 3D anatomy structures' surfaces using small numbers of 2D contours drawn in the most visually informative views of 3D imagery. The innovation of this program is that the number of 2D contours can be very much smaller than the number of transverse sections, even for anatomy structures spanning many sections. This program can edit 3D structures from prior segmentations, including those from autosegmentation programs.

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Purpose: To validate and clinically evaluate autocontouring using atlas-based autosegmentation (ABAS) of computed tomography images.

Methods And Materials: The data from 10 head-and-neck patients were selected as input for ABAS, and neck levels I-V and 20 organs at risk were manually contoured according to published guidelines. The total contouring times were recorded.

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Treatment planning for high precision radiotherapy of head and neck (H&N) cancer patients requires accurate delineation of many structures and lymph node regions. Manual contouring is tedious and suffers from large inter- and intra-rater variability. To reduce manual labor, we have developed a fully automated, atlas-based method for H&N CT image segmentation that employs a novel hierarchical atlas registration approach.

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Image segmentations based on maximum likelihood or maximum a posteriori analyses of object textures usually assume parametric models (e.g., Gaussian) for distributions of these features.

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Electrophysiological data from the rodent whisker/barrel cortex indicate that GABAergic, presumed inhibitory, neurons respond more vigorously to stimulation than glutamatergic, presumed excitatory, cells. However, these data represent very small neuronal samples in restrained, anesthetized, or narcotized animals or in cortical slices. Histochemical data from primate visual cortex, stained for the mitochondrial enzyme cytochrome oxidase (CO) and for GABA, show that GABAergic neurons are more highly reactive for CO than glutamatergic cells, indicating that inhibitory neurons are chronically more active than excitatory neurons but leaving doubt about the short-term stimulus dependence of this activation.

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Objective: Senile plaques (SP) are one of the characteristic neuropathologic lesions of Alzheimer's Disease (AD), and studies of SP cortical distribution, density and morphology may lead to new information about the mechanism and pathogenesis of AD. We used an automated, digital image analysis program to detect and measure SP size, shape and total fractional area in digital images of silver-stained tissue sections.

Study Design: The program observed 94,000 SP in 2,800 digitized microscope fields from tissue sections from 42 postmortem cases ranging from healthy aged to severely demented subjects, studied prospectively before death.

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The one-to-one correspondence of whiskers to barrels in layer IV of rodent somatosensory cortex can be demonstrated by a precise match between columns of heavy 2-deoxyglucose (2DG) label in layer IV barrels and other layers which correspond to stimulated whiskers. While there is specificity of peripheral-to-central mapping, the extent to which integration and/or modulation are generated by circuitry within or interactions between the barrel-defined whisker columns is not clear. Following stimulation of selected whiskers, large cells at the layer IV-V boundary throughout the barrel field are heavily labeled by 2-deoxyglucose (2DG) at high resolution.

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The cerebral cortex is distinguished by layers of neurons of different morphologies and densities. The layers are formed by the migration of newly generated neurons from the ventricular zone to the cortical plate near the outer (pial) boundary of the cortex, along radial paths approximately perpendicular to the cortical surface. Immunochemical labelling makes these cells' patterns visible in brightfield microscopy so that layer formation can be studied.

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Senile plaques (SP) are one of the characteristic neuropathologic lesions of Alzheimer's Disease (AD), and studies of SP cortical distribution, density (number of SP/mm2), and morphology are expected to lead to new information about the mechanism and pathogenesis of AD. We describe a digital image analysis procedure to detect SP, and to measure SP size, shape, and total fractional area in digital micrographs of silver-stained tissue sections. This histology is nonspecific so the program detects all the significant stained objects and a classifier sorts the SP from other tissue elements.

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Senile plaques (SP) are the most characteristic neuropathologic lesions of Alzheimer's disease (AD) and studies of plaque cortical distribution, density, and morphology may lead to new information about the origin and pathogenesis of this disease. We have developed an automated computer image analysis program to detect SP (including diffuse and mature forms) and to measure SP size, shape, and fractional area or load in digital micrographs of silver-stained tissue sections. The plaques are detected with adaptive thresholding, requiring no user interaction.

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The primary motor cortex (M1) is thought to control movements of different body parts from somatotopically organized cortical territories. Electrical stimulation suggests, however, that territories controlling different fingers overlap. Such overlap might be artifactual or else might indicate that activation of M1 to produce a finger movement occurs over a more widespread cortical area than usually assumed.

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Image alignment is an absolute requirement for three-dimensional (3-D) reconstruction from serial sections, and Fourier correlation is the most powerful way to compute alignments. The rotational and translational components of misalignment can be corrected by an iterative correlation procedure, but for images having significant differences, alignment can fail with a likelihood proportional to the extent of the differences. We found that translational correction was determined much more reliably when low-pass filters were applied to the product transforms from which the correlations were calculated.

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Extracellular action potentials of single neurons in motor cortex and rectified and integrated electromyographic activity (EMG) of gastrocnemius and anterior tibialis were recorded while a monkey performed isometric ankle plantar and dorsal flexion tasks. This study determined the consistency of neuronal behaviors across different tasks. Methods characterized neuronal behaviors by determining which behavioral event within a single task, such as the appearance of the 'go' signal, force onset, or agonist and antagonist EMG onset, was best related to changes in neuronal activity.

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Three-dimensional reconstructions from serial section images require the accurate registration of those images. Image correlation is the most powerful computed alignment method and its performance on identical images, or parts thereof, has been thoroughly studied. Correlation alignments of complex, dissimilar images can fail, however, with a likelihood proportional to the magnitude of the differences.

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Glucose utilization was measured in 74 brain regions of the cat during states of wakefulness or rapid eye movement (REM) sleep. These data were obtained from intact, unanesthetized animals which were instrumented for objectively measuring states of consciousness. Through a chronically implanted intravenous catheter, the cats received 250 microCi of magnitude of 6-14C glucose during REM sleep (N = 3) or during wakefulness (N = 3).

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Lenses from rat or calf were exposed in vitro to UV radiation from a nitrogen laser operated at 337.1 nm or from an excimer laser operated at 3.8 nm.

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