Gender differences in the fluorescence of human skin in young healthy adults.

BACKGROUND: Human skin naturally contains many endogenous fluorophores; therefore, fluorescence techniques can be used for monitoring of the human skin even in in vivo mode. The aim of this work was to study skin autofluorescence in vivo regarding the possible effect of gender. MATERIALS AND METHODS: Fluorescence emission spectra of young healthy Caucasian adults in 3 anatomical regions (forehead, hand, and inner upper arm) were taken with excitation at 280, 325, or 400 nm. RESULTS: Three emission bands were found in the spectra for both men and women: (1) an intensive band peaked at 340/280 nm (peak emission/excitation wavelength), corresponding to aromatic amino acids of proteins in epidermis; (2) a broad band with emission between 360 nm and 480 nm (excitation 325 nm) with a base peak around 390 nm and 2 side peaks at 420 and 450 nm, mainly due to collagen cross-links in dermis with a possible weak contribution of elastin and mitochondrial NADPH; (3) a weak but distinct peak at 600/400 nm corresponding presumably to skin unmetalled porphyrins. CONCLUSION: The intensity of skin autofluorescence showed differences between genders and among anatomical regions. The 340 nm intensity was 1.4 times higher in the male group in all 3 anatomical regions studied. The highest intensity of skin autofluorescence for the peaks at 340/280 nm and 600/400 nm was found on the forehead, whereas the 390/325 nm band was most intensive on the inner upper arm in both genders.

The effect of vitamin D3 supplementation on intracellular calcium and plasma membrane calcium ATPase activity in early stages of chronic kidney disease.

Chronic kidney disease (CKD) is associated with increased concentration of intracellular calcium, which is pathological and may lead to irreversible damage of cell functions and structures. The aim of our study was to investigate the impact of 6 months vitamin D(3) supplementation (14 000 IU/week) on free cytosolic calcium concentration ([Ca(2+)](i)) and on the plasma membrane calcium ATPase (PMCA) activity of patients with CKD stage 2-3. PMCA activity of patients was also compared to that of healthy volunteers. Vitamin D(3) supplementation of CKD patients resulted in the decrease of [Ca(2+)](i) (119.79+/-5.87 nmol/l vs. 105.36+/-3.59 nmol/l, n=14, P<0.001), whereas PMCA activity of CKD patients (38.75+/-22.89 nmol P(i)/mg/h) remained unchanged after vitamin D(3) supplementation (40.96+/-17.74 nmol P(i)/mg/h, n=14). PMCA activity of early stage CKD patients before supplementation of vitamin D(3), was reduced by 34 % (42.01+/-20.64 nmol P(i)/mg/h) in comparison to healthy volunteers (63.68+/-20.32 nmol P(i)/mg/h, n=28, P<0.001). These results indicate that vitamin D(3) supplementation had a lowering effect on [Ca(2+)](i) and negligible effect on PMCA activity in CKD patients.

Effects of chronic kidney disease on blood cells membrane properties.

Chronic kidney disease (CKD) is progressive loss of renal function associated among others with increased intracellular calcium concentration. The purpose of this study was to identify the effects of CKD on cell membrane properties such as human red blood cell Ca(2+) ATPase activity, lymphocyte plasma membrane P2X(7) receptor expression and function. This could help us in elucidating the origin of increased calcium concentration in blood cells. We found out Ca(2+) ATPase activity is decreased in early stage CKD patients resulting in altered calcium removal from cytoplasm. By means of flow cytometry we assessed that P2X(7) receptor expression on lymphocyte membrane is 1.5 fold increased for CKD patients. Moreover, we detected an increased uptake of ethidium bromide through this receptor in CKD at basal conditions. It means CKD lymphocyte membranes contain more receptors which are more permeable thus allowing increased calcium influx from extracellular milieu. Finally, we can state alterations in blood cell membranes are closely linked to CKD and may be responsible for intracellular calcium accumulation.