Changes in the structure of collagen in the annulus fibrosus under thermal or IR-laser treatment

Ignatieva, Natalia; Захаркина, О. Л.; Sobol, Emil N.; Лунин, В. В.; Kamensky, Vladislav A.; Андреева, И. В.; Averkiev, S. V.; Myakov, Alexey V.

doi:10.1134/s1607672907020147

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…Δn is obtained via Equation (4), measuring the period (Δ z ) between fringes in the phase retardation image, corresponding with Δ δ = 360 deg. This way, considering only the period between fringes [17], local amplitude variations of phase and reduced SNR in depth do not affect as strongly as in other works (Figure 2b). By measuring the optical-versus-physical thickness of a thin slice [36], the average refractive index of mitral chords is measured as n = 1.389 [37].…”

Section: Methodsmentioning

confidence: 80%

“…Here, birefringence is estimated without the unwrapping step, based on the work of other authors [13,17,35]. Being λ 0 the central wavelength of the source, the estimated birefringence, Δ n , is computed by measuring phase retardation increment (Δ δ ) given a certain penetration (Δ z ): sans-serifΔn=sans-serifΔδ λ02·360 sans-serifΔz…”

Section: Methodsmentioning

confidence: 99%

“…Optical Coherence Tomography (OCT) and Polarization Sensitive Optical Coherence Tomography (PS-OCT) [12,13,14,15] are proposed to assess the structural conditions of the CTs. PS-OCT has been used to evaluate collagen in atherosclerotic plaques [16], changes in vertebral anulus fibrosus [17], altered retinal nerve fiber layer [18], cervix cancer [19], breast cancer detection [20], skin cancer [21] and others. PS-OCT is sensitive to the phase delay produced by birefringent tissues, such as the longitudinally ordered collagen fibers [13].…”

Section: Introductionmentioning

confidence: 99%

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Identification of Human Pathological Mitral Chordae Tendineae Using Polarization-sensitive Optical Coherence Tomography

Real

Icardo

Fernández-Barreras

et al. 2019

Sensors

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Defects of the mitral valve complex imply heart malfunction. The chordae tendineae (CTs) are tendinous strands connecting the mitral and tricuspid valve leaflets to the papillary muscles. These CTs are composed of organized, wavy collagen bundles, making them a strongly birefringent material. Disorder of the collagen structure due to different diseases (rheumatic, degenerative) implies the loss or reduction of tissue birefringence able to be characterized with Polarization Sensitive Optical Coherence Tomography (PS-OCT). PS-OCT is used to discriminate healthy from diseased chords, as the latter must be excised and replaced in clinical conventional interventions. PS-OCT allows to quantify birefringence reduction in human CTs affected by degenerative and rheumatic pathologies. This tissue optical property is proposed as a diagnostic marker for the identification of degradation of tendinous chords to guide intraoperative mitral valve surgery.

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Section: Methodsmentioning

confidence: 80%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Identification of Human Pathological Mitral Chordae Tendineae Using Polarization-sensitive Optical Coherence Tomography

Real

Icardo

Fernández-Barreras

et al. 2019

Sensors

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“…The phenomenon itself can be described in terms of the model of first order phase transition [2]. A dense packing of collagen macromolecules as well as their immobilization by proteoglycan aggregates in hyaline cartilages [3], inorganic microcrystals in bones [4], or fiber fixation and tension in fibrous ring [5] decreases the free volume for polypeptide chains acquiring a coil state after denaturation. This decrease leads to a decrease in the denaturation entropy ΔS d and, as a consequence, to an increase in Т d .…”

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confidence: 99%

Two subsystems of meniscal collagen and their different thermal stabilities

Ignatieva

Захаркина

Лунин

et al. 2012

Dokl Biochem Biophys

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Collagen is the main structural protein of connec tive tissues fulfilling a variety of mechanical functions, including sustenance, support, extension, compres sion, and shear [1]. The structure of the stroma of these tissues depends on how the rod shaped mole cules with a triple helical conformation interact with other macromolecules, how they are packed in fibers, and, in turn, how these fibers are mutually arranged. Manifold structures of this stroma provide for a diver sity of the fulfilled functions.Thermal stability is frequently used as a structural characteristic of various materials, the collagen con taining materials in general and connective tissues in particular being no exclusion. The characteristic of thermal stability is the melting temperature of collagen fibrils, also referred to as denaturation temperature, Т d . The phenomenon itself can be described in terms of the model of first order phase transition [2]. A dense packing of collagen macromolecules as well as their immobilization by proteoglycan aggregates in hyaline cartilages [3], inorganic microcrystals in bones [4], or fiber fixation and tension in fibrous ring [5] decreases the free volume for polypeptide chains acquiring a coil state after denaturation. This decrease leads to a decrease in the denaturation entropy ΔS d and, as a consequence, to an increase in Т d . On the other hand, immobilization of fibrils takes place in the tissues considerably affected by shear stresses; thus, Т d may be not only a structural but also a functional char acteristic of the collagen containing material.The most important function of the meniscus is transmission and redistribution of compression load and stabilization of the joint during its movement. The goal of this work was to determine a thermal stability of the collagen in meniscal tissue and to clarify its corre lation with the functions of the organ. The experimen tal studies have been performed using the specimens isolated from the central part of calf meniscus.The thermodynamic parameters of collagen dena turation (ΔH d and Т d ) in the calf meniscus specimens were determined by differential scanning calorimetry (DSC 30 Mettler TA 4000) at a heating rate of 10 K/min. The heat effects were recalculated per the collagen content in specimen, which was determined using amino acid analysis. The amino acid analysis of hydrolysates of specimens and solutions was con ducted using a Hitachi 835 amino acid analyzer. The balance of type I and type II collagens was estimated based on the difference between molecular ratios r = Hyp/Hyl of the collagen specific amino acids hydrox yproline (Hyp) and hydroxylysine (Hyl). It is known that r I = 15 ± 1 for collagen I and r II = 4.5 ± 0.5 for collagen II [6]. We have elaborated an original algo rithm that allows for determination of the fraction of each collagen type in a specimen from the r value in the amino acid pool of the specimen [7].The fine fiber structure and its changes after heat ing were detected with the help of multiphoton microscopy recording the se...

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Comparative studies of infrared laser and radio-frequency action on in vitro biotissues by the method of polarization sensitive optical coherence tomography

Golubyatnikov

Shakhova

Snopova

et al. 2010

Radiophys Quantum El

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Changes in the structure of collagen in the annulus fibrosus under thermal or IR-laser treatment

Cited by 4 publications

References 8 publications

Identification of Human Pathological Mitral Chordae Tendineae Using Polarization-sensitive Optical Coherence Tomography

Identification of Human Pathological Mitral Chordae Tendineae Using Polarization-sensitive Optical Coherence Tomography

Two subsystems of meniscal collagen and their different thermal stabilities

Comparative studies of infrared laser and radio-frequency action on in vitro biotissues by the method of polarization sensitive optical coherence tomography

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