[Biochemical, structural and biomechanical features of human scleral matrix in primary open-angle glaucoma].

The goal of the investigation was to study the changes of scleral matrix collagen in progressing primary open-angle glaucoma (POAG). In scleral samples of 16 patients aged 52-81 years with different stages of POAG amino acid composition, collagen content and cross-linking ratio characterizing tissue rigidity were estimated. Collagen I was found to be the dominant type in sclera of glaucomatous and normal eyes, though as POAG progressing the content and cross-linking increase, that underlies the scleral rigidity increase and permeability decrease. Similar ratio of collagen cross-linking with age and glaucoma progression give evidence of specific pathologic changes of the dominant matrix component, that may be one of significant pathogenic factor of POAG.

[Decreased collagen stability as a response to the loss of structural integrity of thyroid cartilage].

The thermal behavior, birefringence properties, and the biochemical composition of thyroid cartilage tissues have been studied. The hyaline cartilage, which was visualized as a quasi-isotropic medium, was composed of type II collagen, which did not denature at temperatures up to 100 degrees C. However, in hyaline cartilage digested by trypsin, the denaturation of collagen occured at 60 degrees C. Collagen fibers in the perichondrium were composed of type I and II collagen and formed a highly organized anisotropic structure (birefringence about 4.75 x 10(-3)) with a melting temperature of about 65 degrees C. The temperature of collagen denaturation in perichondrium in the whole system perichondrium-hyaline cartilage increased up to 75 degrees C, indicating the immobilization of perichondrium collagen by the extracellular matrix of the hyaline constituent.

[Effect of infrared laser radiation on sorption of dry cartilage and connective tissue preparations]. / Vliianie lazernogo izlucheniia infrakrasnogo diapazona na sorptsiiu vody sukhimi preparatami khriashchevoi i soedinitel'noi tkanei.

Cartilaginous and connective tissues were exposed to a moderate-intensity IR laser treatment with IR radiometric temperature control. The isotherms of water sorption by dry preparations of intact and laser-treated tissues were obtained and calculated in terms of well known models. It was shown that the sorption capacity of a monolayer of tissues decreases with increasing temperature during laser treatment. Changes in the supramolecular structure of the extracellular matrix of tissues (loss of regularity) upon IR laser exposure are discussed.