Hypovitaminosis D and Its Associated Factors in North Algerian Postmenopausal Women: Results of a Cross-Sectional Study.

PURPOSE: As the vitamin D status of Algerian postmenopausal women was poorly described, this cross-sectional study investigated the prevalence of low vitamin D status in a sample population. Secondarily, predictive factors of this hypovitaminosis D were explored. METHODS: All the 336 selected women ≥ 45 years from Douera were interviewed to get anthropometric and lifestyle data, reproductive and medical history, medications, and calcium/vitamin D intakes. A blood sample was collected to measure 25-hydroxyvitamin D (25(OH)D) concentrations. RESULTS: Approximately 86% of subjects had low vitamin D status (<20 ng/mL). Mean 25(OH)D level was 14.4 ± 5.3 ng/mL with a clear seasonal dynamic and a significant negative correlation with PTH levels (r = -0.15, p=0.006). A multiple regression analysis using the 25(OH)D cutoff value of 17 ng/mL instead of the generally admitted level of 20 ng/mL was performed to increase statistical power. Other seasons than summer (OR 4.159 and 95% CI 2.456-7.043), obesity (≥30 kg/m2, OR 1.826, 95% CI 1.081-3.083), and veiling (OR 3.526, 95% CI 1.090-11.400) were significantly associated with 25(OH)D concentrations <17 ng/mL. CONCLUSIONS: In North Algeria, the abundant sunlight appears insufficient to fully offset hypovitaminosis D risk factors in postmenopausal women, especially obesity and veiling. It suggests the major need to increase vitamin D supplementation in this subpopulation.

Analysis of endothelial protein C receptor functionality on living cells'.

Activated protein C (APC) is a major control system of blood coagulation. APC prevents coagulation pathway by degrading Va and VIIIa plasma's coagulation factors. Protein C activation requires its binding to specific endothelial cell receptor (EPCR). APC binding to EPCR also activates a wide range of defense mechanisms (anti-inflammatory, antiapoptosis...). EPCR expression by cells can be detected by various methods, including immunoanalysis and molecular biology. However, no assays evaluate its functionality. A method, inspired of a standard fibrinoformation time assay, was developed to estimate EPCR ability to bind APC on living cell surface in vitro. Endothelial cells were incubated with APC and fibrinoformation on cells was followed by spectrophotometry (plasma absorbance increases with fibrin polymerization). Membrane-bound EPCR retain APC, thus prolonging fibrinoformation time in a dose-dependent manner. Control was realized with EPCR-negative cells. This new method can be used on any cell type to study the expression of other coagulation receptors.

Angiogenic activity in sera of patients with systemic lupus erythematosus.

Angiogenesis plays a critical role in the pathogenesis of several connective tissue diseases. There is, however, relatively little information available on the role of angiogenesis in systemic lupus erythematosus (SLE). The aim of this study was to investigate the angiogenic activity in sera of patients with SLE and to determine the association between angiogenic activity and clinical complications. Sera from 66 Tunisian females with SLE and from 32 healthy blood donors were studied for their angiogenic activity using the in-vitro tube formation test on Matrigel. Samples were divided into five groups according to their angiogenic activity, which was scored from 0 (no angiogenesis) to 4 (high angiogenic activity). Samples from each group were then tested randomly to assess serum concentration of vascular endothelial growth factor (VEGF). No correlation was found between angiogenic activity scores and serum VEGF levels. Considering angiogenesis assessment in-vitro, sera of patients with SLE showed a much higher angiogenic activity than healthy controls since a high angiogenic score (score 4) is present in 43.9% of patients and in 6.3% of controls (P < 0.0002). This high angiogenic activity is not correlated with disease activity; however, SLE patients with anti-dsDNA antibodies and those with nephritis showed higher angiogenic activity compared with patients without these complications since score 4 is found in 50.9% and 67.9% versus 9.1% (P = 0.017) and 26.3% (P < 0.001), respectively. In conclusion, our study showed that high serum angiogenic activity in SLE was not correlated with the VEGF levels. We suggest the use of the 'in-vitro' tube formation test as a better tool to study the angiogenic potential of sera. We found that in patients with SLE, serum angiogenic activity is increased compared with healthy controls. This high angiogenic activity is associated with renal complications and with the presence of anti-dsDNA antibodies. These findings suggest an involvement of angiogenesis disturbance in the pathogenesis of SLE.

Effect of aeration and agitation on the protease production by Staphylococcus aureus mutant RC128 in a stirred tank bioreactor.

The modified rotating simplex method has been successfully used to determine the best combination of agitation rate and aeration rate for maximum production of extracellular proteases by Staphylococcus aureus mutant RC128, in a stirred tank bioreactor operated in a discontinuous way. This mutant has shown altered exoprotein production, specially enhanced protease production. Maximum production of proteases (15.28 UP/ml), measured using azocasein as a substrate, was obtained at exponential growth phase when the bioreactor was operated at 300 rpm and at 2 vvm with a volumetric oxygen transfer coefficient (K(L)a) of 175.75 h(-1). These conditions were found to be more suitable for protease production.

Expression of extracellular matrix proteins fibulin-1 and fibulin-2 by human corneal fibroblasts.

PURPOSE: The fibulins are a family of extracellular matrix (ECM) molecules that regulate the organ shape along with other growth factors and stromal cells. We report here the in vitro expression of ECM proteins fibulin-1 and fibulin-2 by human corneal fibroblasts. The ability of fibulin-1 to modulate cell motility was investigated. METHODS: Fibulin-1 and fibulin-2 mRNA and proteins expression were analyzed in primary and immortalized human corneal fibroblasts (CHN) respectively by gene array, RT-PCR, and immunocytochemistry. The motility and adhesion of the cells transfected with fibulin-1 siRNA were analyzed on tissue culture polystyrene coated with Matrigel or ECM secreted by those fibroblasts. RESULTS: (1) The microarray analysis shows the expression of fibulin-1, fibulin-2, and their binding partners (i.e., fibronectin, nidogen-1, aggrecan, fibrilin-1, endostatin, and laminin alpha-2 chain). Interestingly, a matrix metalloprotease, ADAMTS-1, for which fibulin-1 acts as a cofactor, was also detected in CHN. (2) The synthesis by CHN of fibulin-1 and 2 mRNA and proteins was confirmed respectively by RT-PCR and immunocytochemistry. (3) Transfection of CHN by fibulin-1 siRNA has no effect on cell adhesion but increases cell migration compared with that of the control cells. This observation suggests an important role of fibulin-1 on cell motility. CONCLUSIONS: The expression of fibulins and that of their binding partners by human corneal fibroblasts indicate the important role of these proteins in the organization of supramolecular ECM structures of cornea. The variation of their expression and the structural changes of fibulins remain to be determined in corneal pathology.

Study of oncogenic potentialities of human melanoma: identification of N-ras oncogene after DNA transfer and tumour induction.

The oncogenic potentialities of human melanoma cells derived from two different patients were studied using DNA-mediated gene transfer into NIH 3T3 cells followed by tumor induction into athymic nude nice. 64% of the mice injected subcutaneously with selected cells which had been co-transfected with human melanoma DNA and the selective marker NeoR developed tumors within 3-4 weeks, while up to 100% of those injected with cells transfected three days before with melanoma DNA developed tumors within 4-6 weeks. Southern blots analysis of the tumors indicated that almost all of them contained human sequences. Hybridization with different oncogene probes showed the presence of an human Eco RI N-ras-hybridizing fragment in the primary and secondary derived tumors, indicating that a transforming N-ras oncogene in human melanoma had been transferred to recipient cells and that transformed cells induced tumors in nude mice.