scholarly journals Effects of collagen crosslinking on porcine and human tarsal plate

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Sarah W. DeParis ◽  
Angela Y. Zhu ◽  
Shoumyo Majumdar ◽  
Jing Tian ◽  
Jennifer Elisseeff ◽  
...  
Keyword(s):  
Tensile Testing ◽  
Anterior Segment ◽  
Characteristic Change ◽  
Type I ◽  
Corneal Tissue ◽  
Collagen Crosslinking ◽  
Porcine Tissue ◽  
Optical Computed Tomography ◽  
Tarsal Plate ◽  
Oct Imaging

Abstract Background Floppy eyelid syndrome is a disorder in which the tarsal plate is easily distensible and is currently treated with conservative or surgical measures. Human tarsal plate contains type I collagen, which is crosslinked in corneal tissue as a treatment for keratoconus. We hypothesized that collagen crosslinking would similarly stiffen tarsal plate tissue and investigated this in porcine and human tarsal plate specimens. Methods Riboflavin-sensitized porcine and human tarsus samples were irradiated with ultraviolet-A light. Porcine experiments were analyzed with gross photographs, anterior segment optical computed tomography (AS-OCT) imaging, and tensile testing. A prospective study of human tarsus was performed on samples from patients undergoing wedge resection for floppy eyelid syndrome and was analyzed with AS-OCT and tensile testing. Results 73 porcine adnexa and 9 patients (16 eyelids) who underwent wedge excision were included in the study. Grossly, greater stiffness was observed in crosslinked porcine tissue. AS-OCT imaging in porcine tissue showed a distinct hyperreflective band in crosslinked specimens whose area and intensity increased with longer treatment time (P = 0.003); this band was also visible in crosslinked human specimens. Tensile testing was performed, but results were not statistically significant. Conclusions AS-OCT imaging, which has not been previously described for tarsal plate, showed a characteristic change in crosslinked porcine and human specimens. Tissue stiffness was increased grossly, but changes in tensile properties were not statistically significant. Further study is warranted to determine relevance as a potential treatment for floppy eyelid syndrome.

scholarly journals Anterior segment OCT imaging in mucopolysaccharidoses type I, II, and VI

Eye ◽  
2014 ◽  
Vol 28 (3) ◽  
pp. 327-336 ◽  
Author(s):  
T Y Ahmed ◽  
A M J Turnbull ◽  
N F Attridge ◽  
S Biswas ◽  
I C Lloyd ◽  
...  
Keyword(s):  
Anterior Segment ◽  
Type I ◽  
Anterior Segment Oct ◽  
Oct Imaging

Assessment of Commercial Off-the-Shelf Tissue Adhesives for Sealing Military-Relevant Corneal Perforation Injuries

2021 ◽  
Author(s):  
Eric J Snider ◽  
Lauren E Cornell ◽  
Brandon M Gross ◽  
David O Zamora ◽  
Emily N Boice
Keyword(s):  
Intraocular Pressure ◽  
High Speed ◽  
Anterior Segment ◽  
Ocular Tissue ◽  
Corneal Tissue ◽  
Corneal Perforation ◽  
Tissue Adhesives ◽  
Open Globe ◽  
Wide Range ◽  
Commercial Off The Shelf

ABSTRACT Introduction Open-globe ocular injuries have increased in frequency in recent combat operations due to increased use of explosive weaponry. Unfortunately, open-globe injuries have one of the worst visual outcomes for the injured warfighter, often resulting in permanent loss of vision. To improve visual recovery, injuries need to be stabilized quickly following trauma, in order to restore intraocular pressure and create a watertight seal. Here, we assess four off-the-shelf (OTS), commercially available tissue adhesives for their ability to seal military-relevant corneal perforation injuries (CPIs). Materials and Methods Adhesives were assessed using an anterior segment inflation platform and a previously developed high-speed benchtop corneal puncture model, to create injuries in porcine eyes. After injury, adhesives were applied and injury stabilization was assessed by measuring outflow rate, ocular compliance, and burst pressure, followed by histological analysis. Results Tegaderm dressings and Dermabond skin adhesive most successfully sealed injuries in preliminary testing. Across a range of injury sizes and shapes, Tegaderm performed well in smaller injury sizes, less than 2 mm in diameter, but inadequately sealed large or complex injuries. Dermabond created a watertight seal capable of maintaining ocular tissue at physiological intraocular pressure for almost all injury shapes and sizes. However, application of the adhesive was inconsistent. Histologically, after removal of the Dermabond skin adhesive, the corneal epithelium was removed and oftentimes the epithelium surface penetrated into the wound and was adhered to inner stromal tissue. Conclusions Dermabond can stabilize a wide range of CPIs; however, application is variable, which may adversely impact the corneal tissue. Without addressing these limitations, no OTS adhesive tested herein can be directly translated to CPIs. This highlights the need for development of a biomaterial product to stabilize these injuries without causing ocular damage upon removal, thus improving the poor vision prognosis for the injured warfighter.

Modulatory Effect of Glycated Collagen on Oral Streptococcal Nanoadhesion

2020 ◽  
Vol 100 (1) ◽  
pp. 82-89
Author(s):  
C.M.A.P. Schuh ◽  
B. Benso ◽  
P.A. Naulin ◽  
N.P. Barrera ◽  
L. Bozec ◽  
...  
Keyword(s):  
Dental Caries ◽  
Biofilm Formation ◽  
Type I Collagen ◽  
Type I ◽  
Oral Streptococci ◽  
Oral Diseases ◽  
Collagen Crosslinking ◽  
Initial Adhesion ◽  
Collagen Glycation ◽  
The Impact

Biofilm-mediated oral diseases such as dental caries and periodontal disease remain highly prevalent in populations worldwide. Biofilm formation initiates with the attachment of primary colonizers onto surfaces, and in the context of caries, the adhesion of oral streptococci to dentinal collagen is crucial for biofilm progression. It is known that dentinal collagen suffers from glucose-associated crosslinking as a function of aging or disease; however, the effect of collagen crosslinking on the early adhesion and subsequent biofilm formation of relevant oral streptococci remains unknown. Therefore, the aim of this work was to determine the impact of collagen glycation on the initial adhesion of primary colonizers such as Streptococcus mutans UA159 and Streptococcus sanguinis SK 36, as well as its effect on the early stages of streptococcal biofilm formation in vitro. Type I collagen matrices were crosslinked with either glucose or methylglyoxal. Atomic force microscopy nanocharacterization revealed morphologic and mechanical changes within the collagen matrix as a function of crosslinking, such as a significantly increased elastic modulus in crosslinked fibrils. Increased nanoadhesion forces were observed for S. mutans on crosslinked collagen surfaces as compared with the control, and retraction curves obtained for both streptococcal strains demonstrated nanoscale unbinding behavior consistent with bacterial adhesin-substrate coupling. Overall, glucose-crosslinked substrates specifically promoted the initial adhesion, biofilm formation, and insoluble extracellular polysaccharide production of S. mutans, while methylglyoxal treatment reduced biofilm formation for both strains. Changes in the adhesion behavior and biofilm formation of oral streptococci as a function of collagen glycation could help explain the biofilm dysbiosis seen in older people and patients with diabetes. Further studies are necessary to determine the influence of collagen crosslinking on the balance between acidogenic and nonacidogenic streptococci to aid in the development of novel preventive and therapeutic treatment against dental caries in these patients.

scholarly journals Types of Lens Structure in Intumescent Cataract

2018 ◽  
Vol 15 (2S) ◽  
pp. 153-159
Author(s):  
E. S. Pirogova ◽  
O. L. Fabrikantov ◽  
S. I. Nikolashin
Keyword(s):  
Irrigation System ◽  
Anterior Segment ◽  
Type I ◽  
Type Ii ◽  
Large White ◽  
Type Iii ◽  
Associated Diseases ◽  
Type Iv ◽  
The Mean ◽  
Anatomical Parameters

Purpose: to study the structure of the swelling lens, the dependence of its anatomical parameters on the nucleus sizes and density, patients’ age.Patients and methods. 52 patients with intumescent mature cataract were examined. All patients underwent phacoemulsification with a two-stage continuous circular capsulorhexis. After the 2–2.5 mm capsulorhexis had been created, the liquid lenticular masses were removed from the anterior and posterior lens compartment with the aspiration/irrigation system. Visually we determined the size of the nucleus, its color and density according to Buratto’s classification.Results. When performing this work 4 types of the swelling lens structure were revealed. Type I — a small emerging white nucleus with large amount of liquid lenticular masses in the anterior and posterior lens compartment, II degree of density according to Buratto’s classification. The mean age was 49.09 ± 3.19 years old. The related ophthalmic diseases accounted for 36.4%. Type II — a large white nucleus with the presence of liquefied lenticular masses in the anterior and posterior lens compartment. III degree of density according to Buratto’s classification. The mean age was 71.00 ± 1.92 years old. Associated diseases — 84.6%. Type III — a large brown nucleus with the presence of liquefied lenticular masses in the anterior and posterior lens compartment. IV degree of density according to Buratto’s classification. The mean age was 75.84 ± 1.46 years old. Associated diseases — 100%. Type IV — a small, very dense, brown nucleus with liquid lenticular masses. V degree of density according to Buratto’s classification. The mean age was 77.33 ± 2.49 years old. Associated diseases — 100%.Conclusion. 4 types of lens structure in intumescent cataract were described depending on the nucleus size, density, the amount of the lenticular masses. By means of UBM method, it was shown that intumescent cataract is accompanied with the alterations of the ocular anterior segment parameters, which depend on the type of lens structure. It was revealed that the types of swelling lens structure are directly connected to the patients’ age: mean age of patients with type I — 49.09 ± 3.19 years old, with type II — 71.00 ± 1.92, with type III — 75.84 ± 1.46, with type IV — 77.33 ± 2.49 years old. 

scholarly journals In-vivo anterior segment OCT imaging provides unique insight into cerulean blue-dot opacities and cataracts in Down syndrome

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Julie-Anne Little ◽  
Aman-Deep S. Mahil ◽  
Patrick Richardson ◽  
J. Margaret Woodhouse ◽  
Valldeflors Vinuela-Navarro ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Anterior Segment ◽  
Anterior Segment Oct ◽  
Oct Imaging ◽  
Insight Into

scholarly journals Ultrasound Biomicroscopy Detects Peters’ Anomaly and Rieger’s Anomaly in Infants

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Wen-Si Chen ◽  
Dao-Man Xiang ◽  
Lan-Xiang Hu
Keyword(s):  
Anterior Chamber ◽  
Anterior Segment ◽  
Corneal Stroma ◽  
Ultrasound Biomicroscopy ◽  
Type I ◽  
Imaging Features ◽  
Type Iv ◽  
Peters Anomaly ◽  
Flat Anterior Chamber ◽  
Corneal Opacities

Aim. Congenital corneal opacities (CCOs) are the major causes of early visual deprivation in infants. Balloon ultrasound biomicroscopy (UBM) examination is an effective method to diagnose CCO. However, whether it is suitable for children examination is still unknown. Methods. 26 Peters’ anomaly (PA) or Rieger’s anomaly (RA) infants with congenital corneal opacities (CCO) (40 eyes) underwent UBM examinations to study their imaging features. Results. Based on the results, they were divided into UBM Dx-Type I: Descemet’s membrane (DM) and endothelium have heterogenous or discontinuous echo accompanied with corneal stroma echo-enhanced or shallow anterior chamber. Type II: Type I alteration plus abnormal strand of iris extended to the border of the posterior corneal defect or iridocorneal adhesion. Type III: Type I or II combined with the abnormal hyperechoic lens, lens luxation, or keratolenticular adhesion. Type IV: echoes of the DM and the endothelium are continuous, corneal stroma echo is enhanced, and an abnormal strand of peripheral iris extends to the prominent Schwalbe line, accompanied by iris stroma or pupil heteromorphism and a shallow or flat anterior chamber. Conclusion. UBM not only could accurately evaluate the anterior segment abnormalities in CCO infants but also would be a step forward for the management of PA- and RA-associated CCO.

Corneal stroma demarcation line after standard and high-intensity collagen crosslinking determined with anterior segment optical coherence tomography

2014 ◽  
Vol 40 (5) ◽  
pp. 736-740 ◽  
Author(s):  
George D. Kymionis ◽  
Konstantinos I. Tsoulnaras ◽  
Michael A. Grentzelos ◽  
Argyro D. Plaka ◽  
Dimitrios G. Mikropoulos ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
High Intensity ◽  
Anterior Segment ◽  
Corneal Stroma ◽  
Optical Coherence ◽  
Demarcation Line ◽  
Collagen Crosslinking

Modeling Study Incorporating Depth-Dependent Transverse Reinforcement due to Variation in Collagen Lamellae Interweaving in Corneal Tissue

2012 ◽  
Author(s):  
Kimberly A. Ziegler ◽  
Thao D. Nguyen
Keyword(s):  
Visual Acuity ◽  
Type I Collagen ◽  
Corneal Thickness ◽  
Corneal Stroma ◽  
Transverse Reinforcement ◽  
Type I ◽  
Corneal Tissue ◽  
Central Cornea ◽  
Strength And Stiffness ◽  
Adverse Affects

The cornea is crucial for maintaining refraction and focusing ability of the eye. Small alterations in mechanical behavior of the tissue can cause changes in curvature and structure of the cornea, having adverse affects on visual acuity. Since the corneal stroma makes up 90% of corneal thickness and contains a majority of the tissue’s collagen content, it is considered the dominant contributor to the tissue’s mechanical strength and stiffness, which originates from a complex fiber-reinforced structure [1]. It has been shown that collagen lamellae (comprised of type I collagen fibrils) within a dense, proteoglycan-rich matrix, are highly interwoven in the anterior third of the cornea and the degree of interweaving decreases significantly through the thickness with relatively no interweaving observed in the posterior third [1]. The interwoven structure also varies within the plane of the tissue, gradually increasing from a planar arrangement in the central cornea to a highly interwoven arrangement near the limbus [2].

scholarly journals The Effect of High Intensity Focused Ultrasound Keratoplasty on Rabbit Anterior Segment

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Menglei Wang ◽  
Meixuan Li ◽  
Pisong Yan ◽  
Qiang Luo ◽  
Yu Zhang ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Collagen Type ◽  
Anterior Segment ◽  
Collagen Type I ◽  
High Intensity Focused Ultrasound ◽  
Type I ◽  
Corneal Cells ◽  
The Right ◽  
Corneal Collagen

Purpose.To evaluate the safety of high-intensity focused ultrasound keratoplasty as a treatment for presbyopia by examining its effect on the rabbit anterior segment.Methods.The right corneas of 36 New Zealand rabbits were treated with HIFU keratoplasty. The animals were sacrificed at 1, 7, 15, 30, 60, and 90 days after operation. Collagen type I, MMP-2, and MMP-9 were evaluated using immunohistochemistry. For the detection of apoptosis, the TUNEL method was applied. The SOD and MDA levels were analyzed with assay kits.Results.Collagen type I, MMP-2, and MMP-9 levels were altered after the operation but returned to normal within 90 days. The apoptotic index (AI) of the corneal cells decreased from 1 to 30 days gradually. No apoptosis was observed in the epithelial cells of the lens, and the SOD and MDA levels were normal at any time point.Conclusion.After HIFU keratoplasty, the histomorphology of the cornea changed, the corneal collagen type I levels decreased, the corneal MMP-2 and MMP-9 levels increased, and the corneal cells underwent apoptosis for a period of time. Ninety days after the operation, the levels returned to normal, and the lenses were not affected. Thus, HIFU presents good biological safety for eyes.

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