Mechanical properties of anterior lens capsule assessed with AFM and nanoindenter in relation to human aging, pseudoexfoliation syndrome, and trypan blue staining
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01.12.2020 |
Efremov Y.M.
Bakhchieva N.A.
Shavkuta B.S.
Frolova A.A.
Kotova S.L.
Novikov I.A.
Akovantseva A.A.
Avetisov K.S.
Avetisov S.E.
Timashev P.S.
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Journal of the Mechanical Behavior of Biomedical Materials |
10.1016/j.jmbbm.2020.104081 |
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Ссылка
© 2020 Elsevier Ltd The purpose of this study is the mechanical characterization of the mid-to- old-age human anterior lens capsules (ALCs) obtained by capsulorhexis using Atomic Force Microscopy (AFM) and a nanoindenter at different spatial scales. The dependencies on the human age, presence or absence of pseudoexfoliation syndrome (PEX), and application of trypan blue staining during the surgery were analyzed. The measurements on both the anterior (AS) and epithelial (ES) sides of the ALC were conducted and the effect of cells present on the epithelial side was carefully accounted for. The ES of the ALC had a homogenous distribution of the Young's modulus over the surface as shown by the macroscale mapping with the nanoindenter and local AFM indentations, while the AS was more heterogeneous. Age-related changes were assessed in groups ranging from the mid-age (from 48 years) to old-age (up to 93 years). We found that the ES was always stiffer than the AS, and this difference decreased with age due to a gradual decrease in the Young's modulus of the ES and an increase in the modulus of the AS. No significant changes were found in the mechanical properties of ALCs of PEX patients versus the PEX-free group, as well as in the properties of the ALC with and without trypan blue staining.
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Biomechanical properties of the lens capsule: A review
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01.03.2020 |
Avetisov K.
Bakhchieva N.
Avetisov S.
Novikov I.
Frolova A.
Akovantseva A.
Efremov Y.
Kotova S.
Timashev P.
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Journal of the Mechanical Behavior of Biomedical Materials |
10.1016/j.jmbbm.2019.103600 |
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Ссылка
© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.
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Biomechanical properties of the lens capsule: A review
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01.03.2020 |
Avetisov K.
Bakhchieva N.
Avetisov S.
Novikov I.
Frolova A.
Akovantseva A.
Efremov Y.
Kotova S.
Timashev P.
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Journal of the Mechanical Behavior of Biomedical Materials |
10.1016/j.jmbbm.2019.103600 |
0 |
Ссылка
© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.
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тезис
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Biomechanical properties of the lens capsule: A review
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01.03.2020 |
Avetisov K.
Bakhchieva N.
Avetisov S.
Novikov I.
Frolova A.
Akovantseva A.
Efremov Y.
Kotova S.
Timashev P.
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Journal of the Mechanical Behavior of Biomedical Materials |
10.1016/j.jmbbm.2019.103600 |
0 |
Ссылка
© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.
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тезис
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Biomechanical properties of the lens capsule: A review
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01.03.2020 |
Avetisov K.
Bakhchieva N.
Avetisov S.
Novikov I.
Frolova A.
Akovantseva A.
Efremov Y.
Kotova S.
Timashev P.
|
Journal of the Mechanical Behavior of Biomedical Materials |
10.1016/j.jmbbm.2019.103600 |
0 |
Ссылка
© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.
Читать
тезис
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Biomechanical properties of the lens capsule: A review
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01.03.2020 |
Avetisov K.
Bakhchieva N.
Avetisov S.
Novikov I.
Frolova A.
Akovantseva A.
Efremov Y.
Kotova S.
Timashev P.
|
Journal of the Mechanical Behavior of Biomedical Materials |
10.1016/j.jmbbm.2019.103600 |
0 |
Ссылка
© 2019 Elsevier Ltd The lens capsule, a thin specialized basement membrane that encloses the crystalline lens, is essential for both the structural and biomechanical integrity of the lens. Knowing the mechanical properties of the lens capsule is important for understanding its physiological functioning, role in accommodation, age-related changes, and for providing a better treatment of a cataract. In this review, we have described the techniques used for the lens capsule biomechanical testing on the macro- and microscale and summarized the current knowledge about its mechanical properties.
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Morphologic versions of postoperative opacities of the lens capsule in contemporary cataract surgery (Working Classification)
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01.01.2018 |
Fedorov A.
Gamidov A.
Motalov V.
Komratova L.
Averkina E.
Kuznetsova M.
Gamidov R.
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Oftalmologiya |
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© 2018 Ophthalmology Publishing Group. All rights reserved. Purpose: creation of working classification of morphologic variations of postoperative lens capsule opacity after Micro-Invasive cataract surgery. Material and methods: Morphologic study of the lens capsule (LC) has been conducted on 4 artiphakic cadaveric eyes. A specimen of an isolated anterior lens capsule, obtained during the repeated operation with changes characteristic for anterior capsular contraction syndrome has been studied too. The obtained specimens have been researched with the method of semithin sections. Results: The analysis of the morphologic cadaveric LC specimens revealed the polymorphism of secondary cataract (SC). Besides well known "classic" SC forms, which were caused by fibroplasias processes or pseudo-regeneration a new type of postoperative LC opacity not represented in the available literature before has been revealed. The given variant of opacities was called "pseudo-hyaloid" form and characterized by the absence of clear LC borders, changes of its normal structure, the appearance of loose fibrillar structure with microslit spaces and exfoliations, that possibly was the consequence of acustic cavitation, arising in the result of ultrasonic effect. As a result the LC lost characteristic for it the role of the dense bed and made impossible adhesion and migration on its changed surface the proliferative fibrocellular elements characteristic for "classic" SC forms. The microscopy results of the isolated anterior LC specimen in the area of capsulotomic aperture showed the presence of altered abundant loose fibrillar tissue with microporous structure and expressed forming of folds. Making layers of fibrous tissue exceeded the thickness of the normal anterior LC in 10 and more times and considerably reduced the diameter of capsulotomic aperture. Conclusion: The variety of postoperative LC opacities confirmed by the results of morphologic studies afforded to suggest a new working classification in which all possible morphologic variants and the stages of the secondary pathologic changes forming of anterior LC. The suggested classification is convenient for the understanding and must promote to make a right algorithm in the choice of optimal and safe technology of laser reconstructive interventions.
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Complex morphological assessment of anterior capsule of the lens in patients with capsular contraction syndrome (a clinical case study)
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01.01.2018 |
Avetisov S.
Gamidov A.
Fyodorov A.
Novikov I.
Averkina E.
Komratova L.
Surnina Z.
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Vestnik Oftalmologii |
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© 2018 Media Sfera. All rights reserved. The anterior capsular contraction syndrome (ACCS) in pseudophakic patients is known to be accompanied by postoperative opacity of anterior lens capsule (ALC) and partial or full closure of anterior capsulotomy opening. Purpose: to perform complex morphological assessment of ALC in patients with ACCS. Material and methods. The study involved complex analysis of ALC that was removed due to ACCS in the pseudophakic eye in the setting of diabetes mellitus and past vitreoretinal surgery. The following examination methods were used: light-optical microscopy of ALC samples in the form of polychrome-colored semifine sections using optical microscope Leica DM-2500 (Germany), scanning microscopy of ALC surface with EVO LS10 (Carl Zeiss, Germany) microscope, analysis of chemical element composition and its variation of the ALC sample with energy-dispersive spectrometer Oxford X-Max50 (Oxford, UK). Results. Light-optical microscopy showed altered state and plication of ALC induced by proliferation from inner surface of the fibrocellular tissue, which gradually thickens (up to 360 µm) towards center and causes reduction of anterior capsulotomy opening. Scanning electron microscopy revealed presence of tissue with uneven micro-relief and a porous three-dimensional structure uncharacteristic for capsule on the surface of ALC. Thickness of the fibrous deposition significantly exceeded the thickness of ALC. Evaluation of elemental composition of the fibrocellular tissue showed elevated concentration of sulfur and phosphorus, which indicates high activity of the regenerative process. In the observed case, the regenerative process was of substitute nature because an attempt to restore the lens was accompanied by formation of connective tissue structurally different from original. Conclusion. Complex assessment of an isolated ALC sample allowed revelation of the chain of pathological processes accompanying the development of ACCS.
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