Evaluation of Foot Structure in Preschool Children Based on Body Mass

BACKGROUND The human foot has a complex structure and the ligamentous and muscular apparatus undergoes transformation and adaptation during its ontogenetic development. Excessive body mass may be one of the factors disrupting proper foot formation. This study aimed to assess the foot structure in preschool children in relation to body mass. MATERIAL AND METHODS A total of 105 children aged 6.27±0.60 years were examined. Height, weight, and segmental body composition were determined using the Tanita MC-780 body composition analyzer. The foot structure was assessed using the Kasperczyk method, supplemented with digital analysis using the Podoscan 2D camera. The Weisflog index and gamma angle for feet were calculated. Children were divided into 2 groups: children in Group I did not have foot deformities and those in Group II had foot deformities. RESULTS No correlation was observed between body mass and the occurrence of anomalies in foot structure. A correlation was noted between the Weisflog index for the right foot and height in both groups. The Weisflog index for both feet was correlated with BMI, with higher values obtained for the left foot in both groups. In Group II, a correlation was observed between the gamma angle value for the left foot and the predicted muscle mass for the right lower limb, as well as between the same foot and the predicted muscle mass for the left lower limb. CONCLUSIONS No correlation was observed between high BMI and the occurrence of anomalies in foot structure. A relationship was identified between muscle mass and foot structure.

The role of retinal pigment epithelium melanin in photoinduced oxidation of ascorbate

To determine the role of major chromophores of the human retinal pigment epithelium (RPE) in photooxidation of ascorbate, we monitored spectrophotometrically rates of ascorbate depletion, induced by blue light, in suspensions of human RPE melanin, melanolipofuscin and lipofuscin and in preparation of pigmented and nonpigmented bovine RPE cells. The results clearly show that melanin is the key retinal pigment responsible for the photosensitized oxidation of exogenous ascorbate. To elucidate the mechanism of the photooxidation process, we used purified RPE melanin granules and synthetic dopa (dihydroxyphenylalanine) melanin and employed electron spin resonance (ESR) spectroscopy, ESR oximetry and oxidase electrode. Our data indicate that photoinduced melanin radicals oxidize ascorbate via one-electron transfer reaction. The reduced melanin is reoxidized by molecular oxygen with the formation of superoxide anion and hydrogen peroxide, while the ascorbate radicals decay by disproportionation. Because in the absence of oxygen, no measurable oxidation of ascorbate is observed, it can be concluded that melanin acts as an electron transfer agent. Biological implications of this study remain unclear; however, the formation of oxygen-reactive species that accompany melanin-mediated photooxidation of ascorbate may represent a potential risk to the RPE that should be minimized by yet unknown cellular mechanisms.

The effect of a synthetic neuromelanin on yield of free hydroxyl radicals generated in model systems

Neuromelanin is an amorphous pigment of the catecholamine origin that accumulates in certain dopaminergic neurons of the substantia nigra of human brain. In Parkinson's disease, there appears to be selective degeneration of the most heavily pigmented neurons of the substantia nigra, and this process has been linked to the presence of neuromelanin. It has been postulated that neuromelanin could increase the risk of oxidative stress reactions. On the other hand, melanin is usually considered to be an efficient antioxidant. Here we analyze experimental conditions that stimulate, or inhibit, antioxidant properties of neuromelanin. Using electron spin resonance (ESR)--spin trapping technique and salicylate hydroxylation assay, we monitored the formation of free hydroxyl radicals generated by a Fenton system in the presence of varying concentration of dopamine-melanin, a synthetic model for neuromelanin. Our data clearly indicate that the antioxidant action of neuromelanin is predominantly due to its ability to sequester redox-active metal ions such as iron. Using direct ESR spectroscopy, we have shown that ferric complexes with neuromelanin are resistant to reduction by mild biological reductants such as ascorbate. We have demonstrated that dopamine-melanin saturated with ferric ions, could enhance the formation of free hydroxyl radicals by redox activation of the ions. Thus, under the conditions that stimulate the release of accumulated metal ions, neuromelanin may actually become an efficient prooxidant. It is conceivable that neuromelanin, which normally is able to protect pigmented dopaminergic neurons against metal-ion related toxicity, could under extreme conditions have a cytotoxic role.