Noninvasive Measurement of Brachial Wall Mechanics During Flow-Mediated Vasodilation Using 2D Ultrasound Strain Tensor Imaging

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192837 ◽

2008 ◽

Author(s):

Ahmed M. Mahmoud ◽

Phoebe A. Stapleton ◽

Jefferson C. Frisbee ◽

Osama M. Mukdadi

Keyword(s):

Fluid Shear Stress ◽

Low Cost ◽

Measurement Techniques ◽

Strain Tensor ◽

Automatic Measurement ◽

Relative Displacement ◽

Contributing Factors ◽

Arterial Diameter ◽

Luminal Diameter

Atherosclerosis has become one of the contributing factors of cardiovascular diseases. Endothelial dysfunction is considered a key factor in the development of atherosclerosis [1]. Flow-mediated vasodilatation (FMD) measurement in brachial and other conduit arteries has become a common method to asses the endothelial function in vivo [2]. Fluid shear-stress increases due to blood flow increases, thus stimulating endothelial cell production and release of nitric oxide, a potent endogenous vasodilator. The mechanical behavior of the arterial wall during vasodilatation is considered an indication for endothelial health. In FMD measurement, the endothelium-dependent variation in arterial diameter in response to reactive ischemia-induced hyperemia is measured by comparing the luminal diameter of the brachial artery before and after the ischemia of the forearm induced by pressurizing a cuff [3]. Ultrasound imaging modalities has been widely used in the FMD analysis as a noninvasive low-cost tool, which can be used to track the arterial diameter change with time. Most of the FMD measurements in the literature are based on tracing the vessel wall boundary manually. Since this process is time consuming and may introduce human errors, automatic measurement techniques have been implemented [3,4]. These techniques utilize image processing algorithms to identify the edges of arterial walls, and then calculate the relative displacement change with time.

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Model-Based Analysis of Flow-Mediated Dilation and Intima-Media Thickness

International Journal of Biomedical Imaging ◽

10.1155/2008/738545 ◽

2008 ◽

Vol 2008 ◽

pp. 1-10 ◽

Cited By ~ 8

Author(s):

G. Bartoli ◽

G. Menegaz ◽

M. Lisi ◽

G. Di Stolfo ◽

S. Dragoni ◽

...

Keyword(s):

Low Cost ◽

A Priori ◽

Automatic Measurement ◽

Intima Media Thickness ◽

Image Features ◽

Flow Mediated Dilation ◽

User Friendliness ◽

Real Time Processing ◽

Media Thickness

We present an end-to-end system for the automatic measurement of flow-mediated dilation (FMD) and intima-media thickness (IMT) for the assessment of the arterial function. The video sequences are acquired from a B-mode echographic scanner. A spline model (deformable template) is fitted to the data to detect the artery boundaries and track them all along the video sequence. The a priori knowledge about the image features and its content is exploited. Preprocessing is performed to improve both the visual quality of video frames for visual inspection and the performance of the segmentation algorithm without affecting the accuracy of the measurements. The system allows real-time processing as well as a high level of interactivity with the user. This is obtained by a graphical user interface (GUI) enabling the cardiologist to supervise the whole process and to eventually reset the contour extraction at any point in time. The system was validated and the accuracy, reproducibility, and repeatability of the measurements were assessed with extensivein vivoexperiments. Jointly with the user friendliness, low cost, and robustness, this makes the system suitable for both research and daily clinical use.

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A technique for protecting delicate specimens during processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156894 ◽

1989 ◽

Vol 47 ◽

pp. 982-983

Author(s):

R.J. Mount ◽

R.V. Harrison

Keyword(s):

Basilar Membrane ◽

Low Cost ◽

Organ Of Corti ◽

Region Of Interest ◽

Sensory Epithelium ◽

Physical Damage ◽

Air Drying ◽

Specimen Handling ◽

Two Component

The sensory end organ of the ear, the organ of Corti, rests on a thin basilar membrane which lies between the bone of the central modiolus and the bony wall of the cochlea. In vivo, the organ of Corti is protected by the bony wall which totally surrounds it. In order to examine the sensory epithelium by scanning electron microscopy it is necessary to dissect away the protective bone and expose the region of interest (Fig. 1). This leaves the fragile organ of Corti susceptible to physical damage during subsequent handling. In our laboratory cochlear specimens, after dissection, are routinely prepared by the O-T- O-T-O technique, critical point dried and then lightly sputter coated with gold. This processing involves considerable specimen handling including several hours on a rotator during which the organ of Corti is at risk of being physically damaged. The following procedure uses low cost, readily available materials to hold the specimen during processing ,preventing physical damage while allowing an unhindered exchange of fluids.Following fixation, the cochlea is dehydrated to 70% ethanol then dissected under ethanol to prevent air drying. The holder is prepared by punching a hole in the flexible snap cap of a Wheaton vial with a paper hole punch. A small amount of two component epoxy putty is well mixed then pushed through the hole in the cap. The putty on the inner cap is formed into a “cup” to hold the specimen (Fig. 2), the putty on the outside is smoothed into a “button” to give good attachment even when the cap is flexed during handling (Fig. 3). The cap is submerged in the 70% ethanol, the bone at the base of the cochlea is seated into the cup and the sides of the cup squeezed with forceps to grip it (Fig.4). Several types of epoxy putty have been tried, most are either soluble in ethanol to some degree or do not set in ethanol. The only putty we find successful is “DUROtm MASTERMENDtm Epoxy Extra Strength Ribbon” (Loctite Corp., Cleveland, Ohio), this is a blue and yellow ribbon which is kneaded to form a green putty, it is available at many hardware stores.

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Organ-specific, multimodal, wireless optoelectronics for high-throughput phenotyping of peripheral neural pathways

Nature Communications ◽

10.1038/s41467-020-20421-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Woo Seok Kim ◽

Sungcheol Hong ◽

Milenka Gamero ◽

Vivekanand Jeevakumar ◽

Clay M. Smithhart ◽

...

Keyword(s):

High Throughput ◽

Low Cost ◽

Optoelectronic Device ◽

Antenna System ◽

Neural Pathways ◽

Organ Specific ◽

Coil Antenna ◽

Sensory Fibers

AbstractThe vagus nerve supports diverse autonomic functions and behaviors important for health and survival. To understand how specific components of the vagus contribute to behaviors and long-term physiological effects, it is critical to modulate their activity with anatomical specificity in awake, freely behaving conditions using reliable methods. Here, we introduce an organ-specific scalable, multimodal, wireless optoelectronic device for precise and chronic optogenetic manipulations in vivo. When combined with an advanced, coil-antenna system and a multiplexing strategy for powering 8 individual homecages using a single RF transmitter, the proposed wireless telemetry enables low cost, high-throughput, and precise functional mapping of peripheral neural circuits, including long-term behavioral and physiological measurements. Deployment of these technologies reveals an unexpected role for stomach, non-stretch vagal sensory fibers in suppressing appetite and demonstrates the durability of the miniature wireless device inside harsh gastric conditions.

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Rapid Fabrication of Microfluidic Devices for Biological Mimicking: A Survey of Materials and Biocompatibility

Micromachines ◽

10.3390/mi12030346 ◽

2021 ◽

Vol 12 (3) ◽

pp. 346

Author(s):

Hui Ling Ma ◽

Ana Carolina Urbaczek ◽

Fayene Zeferino Ribeiro de Souza ◽

Paulo Augusto Gomes Garrido Carneiro Leão ◽

Janice Rodrigues Perussi ◽

...

Keyword(s):

Shear Stress ◽

Cell Viability ◽

Cellular Response ◽

Fluid Shear Stress ◽

Umbilical Vein ◽

Microfluidic Devices ◽

In Vitro Assays ◽

Stress Effect

Microfluidics is an essential technique used in the development of in vitro models for mimicking complex biological systems. The microchip with microfluidic flows offers the precise control of the microenvironment where the cells can grow and structure inside channels to resemble in vivo conditions allowing a proper cellular response investigation. Hence, this study aimed to develop low-cost, simple microchips to simulate the shear stress effect on the human umbilical vein endothelial cells (HUVEC). Differentially from other biological microfluidic devices described in the literature, we used readily available tools like heat-lamination, toner printer, laser cutter and biocompatible double-sided adhesive tapes to bind different layers of materials together, forming a designed composite with a microchannel. In addition, we screened alternative substrates, including polyester-toner, polyester-vinyl, glass, Permanox® and polystyrene to compose the microchips for optimizing cell adhesion, then enabling these microdevices when coupled to a syringe pump, the cells can withstand the fluid shear stress range from 1 to 4 dyne cm2. The cell viability was monitored by acridine orange/ethidium bromide (AO/EB) staining to detect live and dead cells. As a result, our fabrication processes were cost-effective and straightforward. The materials investigated in the assembling of the microchips exhibited good cell viability and biocompatibility, providing a dynamic microenvironment for cell proliferation. Therefore, we suggest that these microchips could be available everywhere, allowing in vitro assays for daily laboratory experiments and further developing the organ-on-a-chip concept.

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Optimizing the Reaction Conditions for the Formation of Fumarate via Trans-Hydrogenation

Applied Magnetic Resonance ◽

10.1007/s00723-021-01371-w ◽

2021 ◽

Author(s):

Laura Wienands ◽

Franziska Theiß ◽

James Eills ◽

Lorenz Rösler ◽

Stephan Knecht ◽

...

Keyword(s):

Aqueous Solution ◽

Thermal Equilibrium ◽

Reaction Rate ◽

Low Cost ◽

Hydrogen Gas ◽

Metabolic Imaging ◽

Reaction Conditions ◽

Precursor Molecule ◽

Solution Preparation

AbstractParahydrogen-induced polarization is a hyperpolarization method for enhancing nuclear magnetic resonance signals by chemical reactions/interactions involving the para spin isomer of hydrogen gas. This method has allowed for biomolecules to be hyperpolarized to such a level that they can be used for real time in vivo metabolic imaging. One particularly promising example is fumarate, which can be rapidly and efficiently hyperpolarized at low cost by hydrogenating an acetylene dicarboxylate precursor molecule using parahydrogen. The reaction is relatively slow compared to the timescale on which the hyperpolarization relaxes back to thermal equilibrium, and an undesirable 2nd hydrogenation step can convert the fumarate into succinate. To date, the hydrogenation chemistry has not been thoroughly investigated, so previous work has been inconsistent in the chosen reaction conditions in the search for ever-higher reaction rate and yield. In this work we investigate the solution preparation protocols and the reaction conditions on the rate and yield of fumarate formation. We report conditions to reproducibly yield over 100 mM fumarate on a short timescale, and discuss aspects of the protocol that hinder the formation of fumarate or lead to irreproducible results. We also provide experimental procedures and recommendations for performing reproducible kinetics experiments in which hydrogen gas is repeatedly bubbled into an aqueous solution, overcoming challenges related to the viscosity and surface tension of the water.

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Genome-wide integration site detection using Cas9 enriched amplification-free long-range sequencing

Nucleic Acids Research ◽

10.1093/nar/gkaa1152 ◽

2020 ◽

Author(s):

Joost van Haasteren ◽

Altar M Munis ◽

Deborah R Gill ◽

Stephen C Hyde

Keyword(s):

Long Range ◽

Insertional Mutagenesis ◽

Lentiviral Vector ◽

Integration Site ◽

Low Cost ◽

Safety Evaluation ◽

Read Length ◽

Chromosomal Dna ◽

Wide Range

Abstract The gene and cell therapy fields are advancing rapidly, with a potential to treat and cure a wide range of diseases, and lentivirus-based gene transfer agents are the vector of choice for many investigators. Early cases of insertional mutagenesis caused by gammaretroviral vectors highlighted that integration site (IS) analysis was a major safety and quality control checkpoint for lentiviral applications. The methods established to detect lentiviral integrations using next-generation sequencing (NGS) are limited by short read length, inadvertent PCR bias, low yield, or lengthy protocols. Here, we describe a new method to sequence IS using Amplification-free Integration Site sequencing (AFIS-Seq). AFIS-Seq is based on amplification-free, Cas9-mediated enrichment of high-molecular-weight chromosomal DNA suitable for long-range Nanopore MinION sequencing. This accessible and low-cost approach generates long reads enabling IS mapping with high certainty within a single day. We demonstrate proof-of-concept by mapping IS of lentiviral vectors in a variety of cell models and report up to 1600-fold enrichment of the signal. This method can be further extended to sequencing of Cas9-mediated integration of genes and to in vivo analysis of IS. AFIS-Seq uses long-read sequencing to facilitate safety evaluation of preclinical lentiviral vector gene therapies by providing IS analysis with improved confidence.

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Hydroxyapatite-incorporation improves bone formation on endosseous PEEK implant in canine tibia

Journal of Applied Biomaterials & Functional Materials ◽

10.1177/2280800020975172 ◽

2020 ◽

Vol 18 ◽

pp. 228080002097517

Author(s):

Yuan-ming Geng ◽

Dong-ni Ren ◽

Shu-yi Li ◽

Zong-yi Li ◽

Xiao-qing Shen ◽

...

Keyword(s):

Bone Formation ◽

Dental Implants ◽

Low Cost ◽

Low Elastic Modulus ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Alternative Material ◽

Ct Analysis ◽

Potential Alternative

Background: Poly Ether Ether Ketone (PEEK) has been considered as a potential alternative material for endosseous dental implants, for its low elastic modulus, biocompatibility, and low cost in customized device manufacture. Hydroxyapatite-incorporation is supposed to improve the poor osseointegration of PEEK. Methods: In the present study we analyzed the in vivo response of hydroxyapatite-incorporated PEEK (PEEK-HA) implants in canine tibia. PEEK-HA and PEEK implants were implanted and were examined 4 weeks and 12 weeks after implantation with radiology and histology. Commercial titanium dental implants served as controls. Results: The ratio of bone volume to tissue volume of PEEK-HA implants was higher than that of PEEK implants 4 weeks after implantation in the μ-CT analysis. The bone implant contact of PEEK and PEEK-HA implants showed no statistical difference in the histological examination, but newly-formed bone around PEEK-HA implants showed more signs of mineralization than that around PEEK implants. Conclusion: The study suggested that bone formation was improved with hydroxyapatite-incorporation in PEEK. Hydroxyapatite-incorporated PEEK implants may represent a potential material for endosseous dental implant.

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Proanthocyanidins against Oxidative Stress: From Molecular Mechanisms to Clinical Applications

BioMed Research International ◽

10.1155/2018/8584136 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 12

Author(s):

Lingyu Yang ◽

Dehai Xian ◽

Xia Xiong ◽

Rui Lai ◽

Jing Song ◽

...

Keyword(s):

Oxidative Stress ◽

Signaling Pathways ◽

Molecular Mechanisms ◽

Metabolic Diseases ◽

Low Cost ◽

Natural Agents ◽

Molecular Damage ◽

And Control

Proanthocyanidins (PCs) are naturally occurring polyphenolic compounds abundant in many vegetables, plant skins (rind/bark), seeds, flowers, fruits, and nuts. Numerousin vitroandin vivostudies have demonstrated myriad effects potentially beneficial to human health, such as antioxidation, anti-inflammation, immunomodulation, DNA repair, and antitumor activity. Accumulation of prooxidants such as reactive oxygen species (ROS) exceeding cellular antioxidant capacity results in oxidative stress (OS), which can damage macromolecules (DNA, lipids, and proteins), organelles (membranes and mitochondria), and whole tissues. OS is implicated in the pathogenesis and exacerbation of many cardiovascular, neurodegenerative, dermatological, and metabolic diseases, both through direct molecular damage and secondary activation of stress-associated signaling pathways. PCs are promising natural agents to safely prevent acute damage and control chronic diseases at relatively low cost. In this review, we summarize the molecules and signaling pathways involved in OS and the corresponding therapeutic mechanisms of PCs.

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