scholarly journals Quantitative Analysis of the Corneal Collagen Distribution after In Vivo Cross-Linking with Second Harmonic Microscopy

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Juan M. Bueno ◽  
Francisco J. Ávila ◽  
M. Carmen Martínez-García
Keyword(s):  
Quantitative Analysis ◽  
Animal Models ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Corneal Stroma ◽  
Cross Linking ◽  
Regular Pattern ◽  
Initial Arrangement ◽  
Corneal Collagen

Corneal cross-linking (CXL) is a surgical procedure able to modify corneal biomechanics and stabilize keratoconus progression. Although it is known that CXL produces changes in corneal collagen distribution, these are still a topic of discussion. Here we quantitatively compare the corneal stroma architecture between two animal models four weeks after in vivo conventional CXL treatment, with second harmonic generation (SHG) imaging microscopy and the structure tensor (ST). The healing stage and the stroma recovery were also analyzed by means of histological sections. Results show that the CXL effects depend on the initial arrangement of the corneal collagen. While the treatment increases the order in corneas with a low level of initial organization, corneas presenting a fairly regular pattern are hardly affected. Histological samples showed active keratocytes in anterior and middle stroma, what means that the recovery is still in progress. The combination of SHG imaging and the ST is able to objectively discriminate the changes suffered by the collagen arrangement after the CXL treatment, whose effectiveness depends on the initial organization of the collagen fibers within the corneal stroma.

scholarly journals Standardization of a method to study angiogenesis in a mouse model

2013 ◽  
Vol 85 (4) ◽  
pp. 1483-1487
Author(s):  
DAVID FEDER ◽  
FABIO F. PERRAZO ◽  
EDIMAR C. PEREIRA ◽  
SILVANA FORSAIT ◽  
CECILIA K.R. FEDER ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Animal Models ◽  
The Other ◽  
In Vivo Studies ◽  
Specific Method ◽  
Test Results ◽  
Hemoglobin Content ◽  
Physiological Conditions ◽  
Adult Organism

In the adult organism, angiogenesis is restricted to a few physiological conditions. On the other hand, uncontrolled angiogenesis have often been associated to angiogenesis-dependent pathologies. A variety of animal models have been described to provide more quantitative analysis of in vivo angiogenesis and to characterize pro- and antiangiogenic molecules. However, it is still necessary to establish a quantitative, reproducible and specific method for studies of angiogenesis factors and inhibitors. This work aimed to standardize a method for the study of angiogenesis and to investigate the effects of thalidomide on angiogenesis. Sponges of 0.5 x 0.5 x 0.5 cm were implanted in the back of mice groups, control and experimental (thalidomide 200 mg/K/day by gavage). After seven days, the sponges were removed. The dosage of hemoglobin in sponge and in circulation was performed and the ratio between the values was tested using nonparametric Mann-Whitney test. Results have shown that sponge-induced angiogenesis quantitated by ratio between hemoglobin content in serum and in sponge is a helpful model for in vivo studies on angiogenesis. Moreover, it was observed that sponge-induced angiogenesis can be suppressed by thalidomide, corroborating to the validity of the standardized method.

scholarly journals Characterization of Collagen I Fiber Thickness, Density, and Orientation in the Human Skin In Vivo Using Second-Harmonic Generation Imaging

Photonics ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 404
Author(s):  
Marius Kröger ◽  
Johannes Schleusener ◽  
Sora Jung ◽  
Maxim E. Darvin
Keyword(s):  
Extracellular Matrix ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Skin Diseases ◽  
Second Harmonic ◽  
Skin Aging ◽  
Collagen I ◽  
Fast Fourier Transformation ◽  
Occurrence Matrix

The assessment of dermal alterations is necessary to monitor skin aging, cancer, and other skin diseases and alterations. The gold standard of morphologic diagnostics is still histopathology. Here, we proposed parameters to distinguish morphologically different collagen I structures in the extracellular matrix and to characterize varying collagen I structures in the skin with similar SAAID (SHG-to-AF Aging Index of Dermis, SHG—second-harmonic generation; AF—autofluorescence) values. Test datasets for the papillary and reticular extracellular matrix from images in 24 female subjects, 36 to 50 years of age, were generated. Parameters for SAAID, edge detection, and fast Fourier transformation directionality were determined. Additionally, textural analyses based on the grey level co-occurrence matrix (GLCM) were conducted. At first, changes in the GLCM parameters were determined in the native greyscale images and, furthermore, in the Hilbert-transformed images. Our results demonstrate a robust set of parameters for noninvasive in vivo classification for morphologically different collagen I structures in the skin, with similar and different SAAID values. We anticipate our method to enable an automated prevention and monitoring system with an age- and gender-specific algorithm.

3D Hotspots Platform for Plasmon Enhanced Raman and Second Harmonic Generation Spectroscopies and Quantitative Analysis

2019 ◽  
Vol 7 (23) ◽  
pp. 1901010 ◽  
Author(s):  
Zhen‐Wei Yang ◽  
Ling‐Yan Meng ◽  
Jia‐Sheng Lin ◽  
Wei‐Min Yang ◽  
Petar Radjenovic ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic
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