Laser threshold and cell damage mechanism for intravascular photoacoustic imaging

2018 ◽  
Vol 51 (5) ◽  
pp. 466-474 ◽  
Author(s):  
Timothy Sowers ◽  
Don VanderLaan ◽  
Andrei Karpiouk ◽  
Eleanor M. Donnelly ◽  
Ethan Smith ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Cell Damage ◽  
Damage Mechanism ◽  
Laser Threshold

Modeling of Bubble Expansion-Induced Cell Mechanical Profile in Laser-Assisted Cell Direct Writing

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Wei Wang ◽  
Gang Li ◽  
Yong Huang
Keyword(s):  
Cell Damage ◽  
Initial Pressure ◽  
Damage Mechanism ◽  
High Viscosity ◽  
Ejection Velocity ◽  
Direct Writing ◽  
Cell Velocity ◽  
Initial Stage ◽  
Approach Zero ◽  
Pressure Magnitude

Cell damage due to the mechanical impact during laser-assisted cell direct writing has been observed and is a possible hurdle for broad applications of fragile cell direct writing. The objective of this study is to numerically investigate the bubble expansion-induced cell mechanical loading profile in laser-assisted cell direct writing. Some conclusions have been drawn as follows. The cell velocity increases initially and then smoothes out gradually with a constant ejection velocity. Both the cell acceleration and pressure can be very high at the beginning period of bubble expansion and then quickly approach zero in an oscillation manner. A high viscosity can lead to an observable velocity increment at the initial stage, but the ejection velocity decreases. The pressure magnitude decreases when the cell-bubble distance is large, and a larger initial pressure induces a larger cell pressure as expected. This study serves as a foundation to further investigate the cell damage mechanism in laser-assisted cell direct writing to improve the effectiveness and efficiency of cell direct writing techniques.

Role of Th17 Cytokines in Liver’s Immune Response during Fatal Yellow Fever:Triggering Cell Damage Mechanism

2021 ◽  
Author(s):  
Marcos Luiz Gaia Carvalho ◽  
Jorge Rodrigues Sousa ◽  
Jeferson Costa Lopes ◽  
Caio Cesar Henriques Mendes ◽  
Fábio Alves Olímpio ◽  
...  
Keyword(s):  
Immune Response ◽  
Cell Damage ◽  
Fatal Outcome ◽  
Immunohistochemical Analysis ◽  
Damage Mechanism ◽  
Cellular Damage ◽  
Hepatic Parenchyma ◽  
Tissue Samples ◽  
Th17 Cytokines ◽  
Th17 Cytokine

Abstract Yellow fever (YF) is an infectious disease whoseevolution and outcome arerelated to the host immune response pattern. We investigated the Th17 cytokine profile in the liver of humans with fatal YF. Liver tissue samples were collected from 26 patients, including 21 YF-positive and five flavivirus-negative patients with preserved hepatic parenchyma architecture who died of other causes. Samples underwent histopathological and immunohistochemical analysis to detect the Th17 profile (ROR-γ, STAT3, IL-6, TGF-β, IL-17,and IL-23). Substantial differences were found in the expression of markers between fatal YF cases and control samples with a predominance of Th17 cytokine markers in the midzonal region of the YF cases, the most affected area in the liver acinus. Histopathological changes in the hepatic parenchyma revealed cellular damage characterised mainly by the presence of inflammatory infiltrate, Councilman bodies (apoptotic cells), micro/macrovesicular steatosis, and lytic and coagulative necrosis.Th17 cytokines play a pivotal role during YF and contribute significantly to triggering the mechanisms of cell damage in the fatal outcome of severe cases.

Modeling of Bubble Expansion-Induced Cell Mechanical Profile in Laser-Assisted Cell Direct Writing

2008 ◽  
Author(s):  
Wei Wang ◽  
Gang Li ◽  
Yong Huang
Keyword(s):  
Cell Damage ◽  
Initial Pressure ◽  
Damage Mechanism ◽  
High Viscosity ◽  
Ejection Velocity ◽  
Direct Writing ◽  
Cell Velocity ◽  
Initial Stage ◽  
Very High ◽  
Pressure Magnitude

Cell damage due to the mechanical impact during laser-assisted cell direct writing has been observed and is a possible hurdle for broad applications of fragile cell direct writing. The objective of this study is to numerically investigate the bubble expansion-induced cell mechanical loading profile in laser-assisted cell direct writing. Some conclusions have been drawn as follows. The cell velocity oscillates initially and then smoothes out gradually with a constant ejection velocity. Both the cell acceleration and pressure can be very high at the beginning period of bubble expansion and then quickly approaches zero in an oscillation manner. A high viscosity can lead to an observable velocity increment at the initial stage, but the ejection velocity decreases. The pressure magnitude decreases when the distance is large, and a larger initial pressure induces a larger cell pressure as expected. This study serves as a foundation to further investigate the cell damage mechanism in laser-assisted cell direct writing to improve the effectiveness and efficiency of cell direct writing techniques.

scholarly journals A Screen of Autophagy Compounds Implicates the Proteasome in Mammalian Aminoglycoside-Induced Hair Cell Damage

2021 ◽  
Vol 9 ◽  
Author(s):  
Clara Draf ◽  
Taylor Wyrick ◽  
Eduardo Chavez ◽  
Kwang Pak ◽  
Arwa Kurabi ◽  
...  
Keyword(s):  
Hair Cell ◽  
Drug Targets ◽  
Fluorescent Protein ◽  
Cell Damage ◽  
Organ Of Corti ◽  
Damage Mechanism ◽  
Green Fluorescent ◽  
Negative Controls ◽  
Cellular Components

Introduction: Autophagy is a degradative pathway to safely break down and recycle dysfunctional cellular components. There is prior evidence of autophagy participation during hair cell (HC) damage. Our goal was to screen compounds targeting different aspects of autophagy for their effects on HC loss due to an ototoxic aminoglycoside, gentamicin (GM).Methods: The SELLECKChem autophagy compound library, consisting of 154 compounds with defined autophagy inducing or inhibitory activity, was used for targeted screening in vitro model of ototoxicity. Organ of Corti from postnatal days 3–5 pou4f3/GFP transgenic mice (HCs express green fluorescent protein) were utilized. The organs were micro-dissected, and basal and middle turns divided into micro-explants individually placed into the single wells of a 96-well plate. Samples were treated with 200 μM of GM plus three dosages of tested compound and cultured for 72 h. Negative controls were treated with media only; positive ototoxicity controls were treated with GM only.Results: The majority of the library compounds had no effect on GM-induced HC loss. However, 18 compounds exhibited a significant, protective effect, two compounds were protective at low dosage but showed enhanced GM toxicity at higher doses and one compound was toxic to HCs in the absence of GM.Conclusions: This study evaluated many autophagy compounds that have not been tested previously on HCs. The disparate results obtained underscore the complexity of autophagy events that can influence HC responses to aminoglycosides, but also implicate the proteosome as an important damage mechanism. The screening results can serve as basis for further studies with protective compounds as potential drug targets.

Electron Probe Analysis of Vertebrate Smooth Muscle: Distribution of Ca and Ci

1976 ◽  
Vol 34 ◽  
pp. 334-335 ◽  
Author(s):  
Avril V. Somlyo ◽  
H. Shuman ◽  
A.P. Somlyo
Keyword(s):  
Smooth Muscle ◽  
Electron Probe ◽  
Preliminary Report ◽  
Cell Damage ◽  
Electron Probe Analysis ◽  
Perinuclear Space ◽  
Probe Analysis ◽  
High K ◽  
Low K ◽  
Initial Results

This is a preliminary report of electron probe analysis of rabbit portal-anterior mesenteric vein (PAMV) smooth muscle cryosectioned without fixation or cryoprotection. The instrumentation and method of electron probe quantitation used (1) and our initial results with cardiac (2) and skeletal (3) muscle have been presented elsewhere.In preparations depolarized with high K (K2SO4) solution, significant calcium peaks were detected over the sarcoplasmic reticulum (Fig 1 and 2) and the continuous perinuclear space. In some of the fibers there were also significant (up to 200 mM/kg dry wt) calcium peaks over the mitochondria. However, in smooth muscle that was not depolarized, high mitochondrial Ca was found in fibers that also contained elevated Na and low K (Fig 3). Therefore, the possibility that these Ca-loaded mitochondria are indicative of cell damage remains to be ruled out.

Histological evaluation of cochlear hair cell damage from noise-induced hearing loss in chinchillas

1990 ◽  
Vol 48 (3) ◽  
pp. 332-333
Author(s):  
R.V. Harrison ◽  
R.J. Mount ◽  
P. White ◽  
N. Fukushima
Keyword(s):  
Hair Cell ◽  
Evoked Potential ◽  
Cell Damage ◽  
Acoustic Trauma ◽  
Histological Evaluation ◽  
Cell Integrity ◽  
Functional Changes ◽  
Cochlear Hair Cell ◽  
Left And Right ◽  
Contralateral Ear

In studies which attempt to define the influence of various factors on recovery of hair cell integrity after acoustic trauma, an experimental and a control ear which initially have equal degrees of damage are required. With in a group of animals receiving an identical level of acoustic trauma there is more symmetry between the ears of each individual, in respect to function, than between animals. Figure 1 illustrates this, left and right cochlear evoked potential (CAP) audiograms are shown for two chinchillas receiving identical trauma. For this reason the contralateral ear is used as control.To compliment such functional evaluations we have devised a scoring system, based on the condition of hair cell stereocilia as revealed by scanning electron microscopy, which permits total stereociliar damage to be expressed numerically. This quantification permits correlation of the degree of structural pathology with functional changes. In this paper wereport experiments to verify the symmetry of stereociliar integrity between two ears, both for normal (non-exposed) animals and chinchillas in which each ear has received identical noise trauma.

Osmolarity and Artificial Cell Damage in Ischemic Myocardium

1990 ◽  
Vol 48 (3) ◽  
pp. 262-263
Author(s):  
Richard Montione ◽  
Muhammad Ashraf
Keyword(s):  
Cell Damage ◽  
Uranyl Acetate ◽  
Tissue Preservation ◽  
Rat Myocardium ◽  
En Bloc ◽  
Cellular Changes ◽  
Artificial Cell ◽  
Cacodylate Buffer ◽  
Isotonic Buffer ◽  
Perfusion Fixation

Osmolarity of a fixative vehicle has long been known to have an effect on the tissue preservation. An increase in tissue osmolarity occurs in ischemia-damaged tissue and affects the morphology. In this study, we examined cellular changes in ischemic rat myocardium induced by varying fixative toxicity.Rats were sacrificed by decapitation and the hearts immediately removed and retrogradily perfused through the aorta with anoxic Kurbs-Henseleit medium. Hearts were then placed in a bag with a small amount of medium at 37°C for 90 minutes. Hearts were perfusion-fixed using 2% glutaraldehyde in 0.1 M cacodylate buffer pH -7.3 at three osmolarities. The isotonic buffer was adjusted to 311 mOsm/kg using D-manitol. Hypertonic buffers were adjusted to 375 and 400 mOsm/kg. One-half hour after perfusion fixation, the hearts were sliced and cut into small blocks and allowed to fix overnight at 4°C. Blocks were post fixed in osmium, en bloc stained in uranyl acetate, dehydrated in ethanol and embedded in Spurr medium.

Elemental mass loss in silicate minerals during x-ray analysis

1990 ◽  
Vol 48 (4) ◽  
pp. 804-805
Author(s):  
P.E. Champness ◽  
R.W. Devenish
Keyword(s):  
Mass Loss ◽  
Current Density ◽  
Damage Mechanism ◽  
Beam Current ◽  
Single Chain ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Alkali Ions ◽  
Structural Order ◽  
Sheet Silicate

It has long been recognised that silicates can suffer extensive beam damage in electron-beam instruments. The predominant damage mechanism is radiolysis. For instance, damage in quartz, SiO2, results in loss of structural order without mass loss whereas feldspars (framework silicates containing Ca, Na, K) suffer loss of structural order with accompanying mass loss. In the latter case, the alkali ions, particularly Na, are found to migrate away from the area of the beam. The aim of the present study was to investigate the loss of various elements from the common silicate structures during electron irradiation at 100 kV over a range of current densities of 104 - 109 A m−2. (The current density is defined in terms of 50% of total current in the FWHM probe). The silicates so far ivestigated are:- olivine [(Mg, Fe)SiO4], a structure that has isolated Si-O tetrahedra, garnet [(Mg, Ca, Fe)3Al2Si3AO12 another silicate with isolated tetrahedra, pyroxene [-Ca(Mg, Fe)Si2O6 a single-chain silicate; mica [margarite, -Ca2Al4Si4Al4O2O(OH)4], a sheet silicate, and plagioclase feldspar [-NaCaAl3Si5O16]. Ion- thinned samples of each mineral were examined in a VG Microscopes UHV HB501 field- emission STEM. The beam current used was typically - 0.5 nA and the current density was varied by defocussing the electron probe. Energy-dispersive X-ray spectra were collected every 10 seconds for a total of 200 seconds using a Link Systems windowless detector. The thickness of the samples in the area of analysis was normally 50-150 nm.

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