scholarly journals Hyperspectral Imagery for Assessing Laser-Induced Thermal State Change in Liver

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 643
Author(s):  
Martina De Landro ◽  
Ignacio Espíritu García-Molina ◽  
Manuel Barberio ◽  
Eric Felli ◽  
Vincent Agnus ◽  
...  
Keyword(s):  
Thermal Damage ◽  
Thermal State ◽  
Preliminary Investigation ◽  
Spectral Band ◽  
Spectral Variation ◽  
Ablation Therapy ◽  
Clinical Endpoints ◽  
Breathing Motion ◽  
Living Tissues

This work presents the potential of hyperspectral imaging (HSI) to monitor the thermal outcome of laser ablation therapy used for minimally invasive tumor removal. Our main goal is the establishment of indicators of the thermal damage of living tissues, which can be used to assess the effect of the procedure. These indicators rely on the spectral variation of temperature-dependent tissue chromophores, i.e., oxyhemoglobin, deoxyhemoglobin, methemoglobin, and water. Laser treatment was performed at specific temperature thresholds (from 60 to 110 °C) on in-vivo animal liver and was assessed with a hyperspectral camera (500–995 nm) during and after the treatment. The indicators were extracted from the hyperspectral images after the following processing steps: the breathing motion compensation and the spectral and spatial filtering, the selection of spectral bands corresponding to specific tissue chromophores, and the analysis of the areas under the curves for each spectral band. Results show that properly combining spectral information related to deoxyhemoglobin, methemoglobin, lipids, and water allows for the segmenting of different zones of the laser-induced thermal damage. This preliminary investigation provides indicators for describing the thermal state of the liver, which can be employed in the future as clinical endpoints of the procedure outcome.

Nonthermal Irreversible Electroporation for Tissue Decellularization

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Mary Phillips ◽  
Elad Maor ◽  
Boris Rubinsky
Keyword(s):  
Thermal Damage ◽  
Irreversible Electroporation ◽  
Electrical Parameters ◽  
Irreversible Damage ◽  
Tissue Scaffold ◽  
Electrical Fields ◽  
Nonthermal Irreversible Electroporation ◽  
Tissue Scaffolding ◽  
Living Tissues

Tissue scaffolding is a key component for tissue engineering, and the extracellular matrix (ECM) is nature’s ideal scaffold material. A conceptually different method is reported here for producing tissue scaffolds by decellularization of living tissues using nonthermal irreversible electroporation (NTIRE) pulsed electrical fields to cause nanoscale irreversible damage to the cell membrane in the targeted tissue while sparing the ECM and utilizing the body’s host response for decellularization. This study demonstrates that the method preserves the native tissue ECM and produces a scaffold that is functional and facilitates recellularization. A two-dimensional transient finite element solution of the Laplace and heat conduction equations was used to ensure that the electrical parameters used would not cause any thermal damage to the tissue scaffold. By performing NTIRE in vivo on the carotid artery, it is shown that in 3 days post NTIRE the immune system decellularizes the irreversible electroporated tissue and leaves behind a functional scaffold. In 7 days, there is evidence of endothelial regrowth, indicating that the artery scaffold maintained its function throughout the procedure and normal recellularization is taking place.

scholarly journals Survival and Proliferation under Severely Hypoxic Microenvironments Using Cell-Laden Oxygenating Hydrogels

2021 ◽  
Vol 12 (2) ◽  
pp. 30
Author(s):  
Shabir Hassan ◽  
Berivan Cecen ◽  
Ramon Peña-Garcia ◽  
Fernanda Roberta Marciano ◽  
Amir K. Miri ◽  
...  
Keyword(s):  
Prolonged Release ◽  
Therapeutic Approaches ◽  
Encapsulated Cells ◽  
Hypoxic Conditions ◽  
Skeletal Myoblasts ◽  
Artificial Tissue ◽  
Delivery Platform ◽  
Living Tissues

Different strategies have been employed to provide adequate nutrients for engineered living tissues. These have mainly revolved around providing oxygen to alleviate the effects of chronic hypoxia or anoxia that result in necrosis or weak neovascularization, leading to failure of artificial tissue implants and hence poor clinical outcome. While different biomaterials have been used as oxygen generators for in vitro as well as in vivo applications, certain problems have hampered their wide application. Among these are the generation and the rate at which oxygen is produced together with the production of the reaction intermediates in the form of reactive oxygen species (ROS). Both these factors can be detrimental for cell survival and can severely affect the outcome of such studies. Here we present calcium peroxide (CPO) encapsulated in polycaprolactone as oxygen releasing microparticles (OMPs). While CPO releases oxygen upon hydrolysis, PCL encapsulation ensures that hydrolysis takes place slowly, thereby sustaining prolonged release of oxygen without the stress the bulk release can endow on the encapsulated cells. We used gelatin methacryloyl (GelMA) hydrogels containing these OMPs to stimulate survival and proliferation of encapsulated skeletal myoblasts and optimized the OMP concentration for sustained oxygen delivery over more than a week. The oxygen releasing and delivery platform described in this study opens up opportunities for cell-based therapeutic approaches to treat diseases resulting from ischemic conditions and enhance survival of implants under severe hypoxic conditions for successful clinical translation.

scholarly journals Application of the 1-µsec pulsed-dye laser to the treatment of experimental cerebral vasospasm

1991 ◽  
Vol 75 (2) ◽  
pp. 271-276 ◽  
Author(s):  
Atsushi Teramura ◽  
Robert Macfarlane ◽  
Christopher J. Owen ◽  
Ralph de la Torre ◽  
Kenton W. Gregory ◽  
...  
Keyword(s):  
Cerebral Vasospasm ◽  
Basilar Artery ◽  
Laser Energy ◽  
Autologous Blood ◽  
Preliminary Investigation ◽  
Dye Laser ◽  
Pulsed Dye Laser ◽  
Content Type

✓ Laser energy of 480 nm was applied in 1-µsec pulses varying between 2.2 and 10 mJ to in vitro and in vivo models of cerebral vasospasm. First, the pulsed-dye laser was applied intravascularly via a 320-µm fiber to basilar artery segments from six dogs. The segments were mounted in a vessel-perfusion apparatus and constricted to, on average, 70% of resting diameter by superfusion with dog hemolysate. Immediate increase in basilar artery diameter occurred to a mean of 83% of control. In a second model, the basilar artery was exposed transclivally in the rabbit. In three normal animals, superfusion of the artery with rabbit hemolysate resulted in a reduction of mean vessel diameter to 81% of control. Following extravascular application of the laser, vessels returned to an average of 106% of the resting state. In six rabbits, the basilar artery was constricted by two intracisternal injections of autologous blood, 3 days apart. Two to 4 days after the second injection, the basilar artery was exposed. Extravascular laser treatment from a quartz fiber placed perpendicular to the vessel adventitia resulted in an immediate 53% average increase in caliber to an estimated 107% of control. No reconstriction was observed over a period of up to 5 hours. Morphologically, damage to the arterial wall was slight. This preliminary investigation suggests that the 1-µsec pulsed-dye laser may be of benefit in the treatment of cerebral vasospasm.

Persistent Luminescence Cr3+ Doped Spinels and Use as Biomarker for In Vivo Imaging

2014 ◽  
Vol 90 ◽  
pp. 157-165
Author(s):  
Suchinder K. Sharma ◽  
D. Gourier ◽  
B. Viana ◽  
T. Maldiney ◽  
E. Teston ◽  
...  
Keyword(s):  
Uv Light ◽  
Red Light ◽  
Band Gap Energy ◽  
Transparency Window ◽  
Persistent Luminescence ◽  
High Brightness ◽  
Mouse Imaging ◽  
Classical Quantum ◽  
Living Tissues

ZnGa2O4(ZGO) is a normal spinel. When doped with Cr3+ions, ZGO:Cr becomes a high brightness persistent luminescence material with an emission spectrum perfectly matching the transparency window of living tissues. It allowsin vivomouse imaging with a better signal to background ratio than classical quantum dots. The most interesting characteristic of ZGO:Cr lies in the fact that its LLP can be excited with red light, well below its band gap energy and in the transparency window of living tissues. A mechanism based on the trapping of carriers localized around a special type of Cr3+ions namely CrN2can explain this singularity. The antisite defects of the structure are the main responsible traps in the persistent luminescence mechanism. When located around Cr3+ions, they allow, via Cr3+absorption, the storage of not only UV light but also all visible light from the excitation source.

Ultrasound-based sensors for respiratory motion assessment in multimodality PET imaging

2021 ◽  
Author(s):  
Bruno Madore ◽  
Gabriela Belsley ◽  
Cheng-Chieh Cheng ◽  
Frank Preiswerk ◽  
Marie Foley Kijewski ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Respiratory Gating ◽  
Sensitive Information ◽  
Internal Organs ◽  
Respiration Monitoring ◽  
Breathing Motion ◽  
Pet Ct ◽  
Motion Phantom ◽  
Motion Assessment

Abstract Breathing motion can displace internal organs by up to several cm; as such, it is a primary factor limiting image quality in medical imaging. Motion can also complicate matters when trying to fuse images from different modalities, acquired at different locations and/or on different days. Currently available devices for monitoring breathing motion often do so indirectly, by detecting changes in the outline of the torso rather than the internal motion itself, and these devices are often fixed to floors, ceilings or walls, and thus cannot accompany patients from one location to another. We have developed small ultrasound-based sensors, referred to as ‘organ configuration motion’ (OCM) sensors, that attach to the skin and provide rich motion-sensitive information. In the present work we tested the ability of OCM sensors to enable respiratory gating during in vivo PET imaging. A motion phantom involving an FDG solution was assembled, and two cancer patients scheduled for a clinical PET/CT exam were recruited for this study. OCM signals were used to help reconstruct phantom and in vivo data into time series of motion-resolved images. As expected, the motion-resolved images captured the underlying motion. In Patient #1, a single large lesion proved to be mostly stationary through the breathing cycle. However, in Patient #2, several small lesions were mobile during breathing, and our proposed new approach captured their breathing-related displacements. In summary, a relatively inexpensive hardware solution was developed here for respiration monitoring. Because the proposed sensors attach to the skin, as opposed to walls or ceilings, they can accompany patients from one procedure to the next, potentially allowing data gathered in different places and at different times to be combined and compared in ways that account for breathing motion.

scholarly journals Application of optogenetic Amyloid-β distinguishes between metabolic and physical damages in neurodegeneration

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Chu Hsien Lim ◽  
Prameet Kaur ◽  
Emelyne Teo ◽  
Vanessa Yuk Man Lam ◽  
Fangchen Zhu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Progression ◽  
Biological Effects ◽  
Amyloid Β ◽  
Tissue Loss ◽  
Amyloid Β Peptide ◽  
Physical Damage ◽  
Living Tissues

The brains of Alzheimer’s disease patients show a decrease in brain mass and a preponderance of extracellular Amyloid-β plaques. These plaques are formed by aggregation of polypeptides that are derived from the Amyloid Precursor Protein (APP). Amyloid-β plaques are thought to play either a direct or an indirect role in disease progression, however the exact role of aggregation and plaque formation in the aetiology of Alzheimer’s disease (AD) is subject to debate as the biological effects of soluble and aggregated Amyloid-β peptides are difficult to separate in vivo. To investigate the consequences of formation of Amyloid-β oligomers in living tissues, we developed a fluorescently tagged, optogenetic Amyloid-β peptide that oligomerizes rapidly in the presence of blue light. We applied this system to the crucial question of how intracellular Amyloid-β oligomers underlie the pathologies of A. We use Drosophila, C. elegans and D. rerio to show that, although both expression and induced oligomerization of Amyloid-β were detrimental to lifespan and healthspan, we were able to separate the metabolic and physical damage caused by light-induced Amyloid-β oligomerization from Amyloid-β expression alone. The physical damage caused by Amyloid-β oligomers also recapitulated the catastrophic tissue loss that is a hallmark of late AD. We show that the lifespan deficit induced by Amyloid-β oligomers was reduced with Li+ treatment. Our results present the first model to separate different aspects of disease progression.

scholarly journals SREBP1 drives KRT80-dependent cytoskeletal changes and invasive behavior in endocrine resistant ERα breast cancer

2018 ◽  
Author(s):  
Ylenia Perone ◽  
Aaron J. Farrugia ◽  
Alba Rodriguez Meira ◽  
Balázs Győrffy ◽  
Charlotte Ion ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Invasion ◽  
De Novo ◽  
Regulatory Element ◽  
Leading Edge ◽  
Clinical Endpoints ◽  
Breast Cancer Relapse ◽  
Element Binding Protein ◽  
Cytoskeletal Rearrangements

AbstractApproximately 30% of women diagnosed with ERα breast cancer relapse with metastatic disease following adjuvant treatment with endocrine therapies1,2. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain (TAD)3 undergoes epigenetic reprogramming in cells that develop resistance to aromatase inhibitors (AI), leading to keratin 80 (KRT80) upregulation. In agreement, an increased number of KRT80-positive cells are observed at relapse in vivo while KRT80 expression associates with poor outcome using several clinical endpoints. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 14 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion maturation and cellular stiffening, which collectively promote cancer cell invasion. Shear-wave elasticity imaging of prospective patients shows that KRT80 levels correlate with stiffer tumors in vivo. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment.

scholarly journals Crosstalk Between Nuclear MET and SOX9/β-Catenin Correlates with Castration-Resistant Prostate Cancer

2014 ◽  
Vol 28 (10) ◽  
pp. 1629-1639 ◽  
Author(s):  
Yingqiu Xie ◽  
Wenfu Lu ◽  
Shenji Liu ◽  
Qing Yang ◽  
Brett S. Carver ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Combined Treatment ◽  
Castration Resistant Prostate Cancer ◽  
Ablation Therapy ◽  
Androgen Ablation ◽  
Castration Resistant ◽  
Activate Cell ◽  
Androgen Ablation Therapy

Castration-resistant prostate cancer (PCa) (CRPC) is relapse after various forms of androgen ablation therapy and causes a major mortality in PCa patients, yet the mechanism remains poorly understood. Here, we report the nuclear form of mesenchymal epithelial transition factor (nMET) is essential for CRPC. Specifically, nMET is remarkably increased in human CRPC samples compared with naïve samples. Androgen deprivation induces endogenous nMET and promotes cell proliferation and stem-like cell self-renewal in androgen-nonresponsive PCa cells. Mechanistically, nMET activates SRY (sex determining region Y)-box9, β-catenin, and Nanog homeobox and promotes sphere formation in the absence of androgen stimulus. Combined treatment of MET and β-catenin enhances the inhibition of PCa cell growth. Importantly, MET accumulation is detected in nucleus of recurrent prostate tumors of castrated Pten/Trp53 null mice, whereas MET elevation is predominantly found in membrane of naïve tumors. Our findings reveal for the first time an essential role of nMET association with SOX9/β-catenin in CRPC in vitro and in vivo, highlighting that nuclear RTK activate cell reprogramming to drive recurrence, and targeting nMET would be a new avenue to treat recurrent cancers.

Measurement of the Optical Properties of Muscle Tissue In Vivo

2000 ◽  
Author(s):  
P. L. Kopsombut ◽  
D. Willis ◽  
A. E. Schen ◽  
L. X. Xu ◽  
X. Xu
Keyword(s):  
Optical Properties ◽  
Transport Theory ◽  
Rapid Development ◽  
Ccd Camera ◽  
High Sensitivity ◽  
Biological Tissues ◽  
In Vivo Measurement ◽  
Living Tissues

Abstract Along with rapid development of diagnostic and therapeutic applications of lasers in medicine, optical properties of various biological tissues have been extensively studied [1]. Most of the studies were performed in vitro owing to the complexity involved in in vivo measurement. To date, it is well understood that living tissue is an absorbing and scattering heterogeneous medium because of its complex structures including blood network. The transport theory cannot be readily used due to the heterogeneity and the absence of the optical properties of living tissues [2]. In this research, we have developed a procedure for measuring the total attenuation coefficient (μ1) of the exteriorized rat 2-D spinotrapezius muscle in the wavelength ranged from 480–560 nm using the collimated light from a Nitrogen-pumped dye laser and a high-sensitivity CCD camera.

Sign in / Sign up

Export Citation Format

Share Document