Articular cartilage: collagen II-proteoglycans interactions. Availability of reactive groups. Variation in birefringence and differences as compared to collagen I.

Intrinsic (IB) and form or textural birefringence curves (FBC) were obtained measuring optical path differences in non stained sections of articular cartilages. Differences were not detected when comparing IB and FBC of the articular surface with those of the intermediate zone (Collagen II), but were found when these curves were compared with those of tendons (Collagen I). A detailed description of arrangements of collagen fibers are reported with no confirmation of Gothic arches. Hyaluronidase and papain digestion caused a decrease in birefringence of the cartilage supporting the conclusion that acid proteoglycans (APG) present molecular orientation in those structures. Histochemical data and histophotometric measurements confirmed that in articular cartilage there are variations in APG concentration and complexation with Collagen II from the articular surface (AS) down to the bone zone, AS displaying much more available -NH3+ groups. Molecular order in the articular cartilage optimizes the state of aggregation in its structures, and is the basis for its piezoelectric and mechanical properties.

[Multivaried analysis of the interaction between quality of life and physical capacities for people occupationally intoxicated by mercury]. / Análise multivariada da interação entre qualidade de vida e capacidades físicas em intoxicados ocupacionais por mercúrio.

INTRODUCTION: One important aggression to human biology is constituted by metallic mercury intoxication, mainly expressed by neuropsychiatric disorders. OBJECTIVE: To explore interaction between the domains of Quality of Life (QoL.) and neuro-muscular evidences in intoxicated people by the metal within an urban-industrial environment. MATERIAL AND METHODS: 47 patients have been assessed, through SF36 application and semiological tests. Multiple regression was performed and, to test parameters estimated in adjustments, Student t test was used. RESULTS: Although there are low scores present in the instrument, there have been noticed good results in physical capacities. Muscular strength seems to be an influencing variable on physical and social functioning and mental health (p<0.05). Motor coordination influence on Vitality (p <0.05) was also remarked. As to equilibrium, it presents a negative interaction (p <0.03) with social functioning. CONCLUSIONS: Neuropsychiatric disorders influence negatively QoL perception, making people to subestime their motor performances. Complementarily, it is distinguished strength as physical capacity that presents positive interaction with the subjective perception of QV.

Anisotropic and biomechanical properties of tendons modified by exercise and denervation: aggregation and macromolecular order in collagen bundles.

For the purpose of determining the changes in tensile strength and levels of macromolecular orientation in collagen bundles as a result of mechanical stimuli, rats were submitted to different experimental treatments such as physical exercise and muscular denervation. After these treatments the Achilles tendons of the animals were submitted to biomechanical and biophysical testing. An analysis of the "stress"-strain curves indicated that the tendons of trained animals possessed superior tensile strength characteristics as compared to their controls. The form birefringence curves (FBC) of the collagen bundles in these tendons also showed an increase in their state of aggregation of the extracellular matrix elements, while maintaining their levels of crystallinity. Average values of tensile strength were even higher in the tendons of denervated animals. An accentuation of the profile of the FBC was also observed in these tendons. The determination of the biomechanical and biophysical modifications can contribute to the understanding of the probable control mechanisms of the aggregation state patterns of the fibrous elements of the extracellular matrix.