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Introduction: In this paper, we investigated whether cholecalciferol supplementation may increase the risk of stone recurrence in patients with calcium nephrolithiasis and Vitamin D deficiency. Methods: Thirty-three stone formers (56 ± 17 years old, 12 males) with 25(OH)D < 20 ng/mL were considered. Calcium excretion and urine supersaturation with calcium oxalate (ßCaOx) and brushite (ßbsh) were evaluated, both before and after cholecalciferol supplementation. Values of ß > 1 mean supersaturation. Cholecalciferol was prescribed as oral bolus of 100,000–200,000 IU, followed by weekly (5000–10,000 IU) or monthly (25,000–50,000 IU) doses. Calcium intake varied between 800 and 1000 mg/day. In urine, total nitrogen (TNE) was taken as an index of protein intake, sodium as a marker of dietary intake, and net acid excretion (NAE) as an index of acid–base balance. Results: TNE, sodium, and NAE did not change during the study (p = ns). Compared to baseline values, after cholecalciferol, both serum calcium and phosphate did not vary (p = ns); 25(OH)D increased from 11.8 ± 5.5 to 40.2 ± 12.2 ng/mL (p < 0.01); 1.25(OH)2D increased from 41.6 ± 17.6 to 54 ± 16 pg/mL (p < 0.01); PTH decreased from 75 ± 27.2 to 56.7 ± 21.1 pg/mL (p < 0.01); urinary calcium increased from 2.7 ± 1.5 to 3.6 ± 1.6 mg/Kg b.w. (p < 0.01); ßbsh increased from 0.9 ± 0.7 to 1.3 ± 1.3 (p = 0.02); whereas ßCaOx varied but not significantly. Before cholecalciferol supplementation, 6/33 patients were hypercalciuric (i.e., urine Ca ≥ 4 mg/Kg b.w.) and increased to 13/33 after cholecalciferol supplementation (pX2 = 0.03). Conclusions: Cholecalciferol supplementation may increase calcium excretion, or reveal an underlying condition of absorptive hypercalciuria. This may increase both urine supersaturation with calcium salts and stone-forming risk. [ABSTRACT FROM AUTHOR]

Among other components of the extracellular matrix (ECM), glycoproteins and glycosaminoglycans (GAGs) have been strongly associated to the retention or misfolding of different proteins inducing the formation of deposits in amyloid diseases. The composition of these molecules is highly diverse and a key issue seems to be the equilibrium between physiological and pathological events. In order to have a model in which the composition of the matrix could be finely controlled, we designed and synthesized crosslinked hydrophilic polymers, the so-called hydrogels varying the amounts of negative charges and hydroxyl groups that are prevalent in GAGs. We checked and compared by fluorescence techniques the binding of human apolipoprotein A-I and a natural mutant involved in amyloidosis to the hydrogel scaffolds. Our results indicate that both proteins are highly retained as long as the negative charge increases, and in addition it was shown that the mutant is more retained than the Wt, indicating that the retention of specific proteins in the ECM could be part of the pathogenicity. These results show the importance of the use of these polymers as a model to get deep insight into the studies of proteins within macromolecules. [ABSTRACT FROM AUTHOR]

Methyl-β-cyclodextrins (MβCDs) are molecules that are extensively used to remove and to load cholesterol (Chol) from artificial and natural membranes; however, the mechanism of Chol extraction by MβCD from pure lipids or from complex mixtures is not fully understood. One of the outstanding questions in this field is the capability of MβCD to remove Chol from lipid domains having different packing. Here, we investigated the specificity of MβCD to remove Chol from coexisting macrodomains with different lipid packing. We used giant unilamellar vesicles (GUVs) made of 1,2-dioleoylphosphatidylcholine:1,2-dipalmitoylphatidylcholine:free cholesterol, 1:1:1 molar ratio at 27°C. Under these conditions, individual GUVs present Chol distributed into lo and ld phases. The two phases can be distinguished and visualized using Laurdan generalized polarization and two-photon excitation fluorescence microscopy. Our data indicate that MβCD removes Chol preferentially from the more disordered phase. The process of selective Chol removal is dependent on the MβCD concentration. At high concentrations, MβCD also removes phospholipids. [ABSTRACT FROM AUTHOR]

This paper considers numerical simulations of fluid-structure interaction (FSI) problems in hemodynamics for idealized geometries of healthy cerebral arteries modeled by both nonlinear isotropic and anisotropic material constitutive laws. In particular, it focuses on an anisotropic model initially proposed for cerebral arteries to characterize the activation of collagen fibers at finite strains. In the current work, this constitutive model is implemented for the first time in the context of an FSI formulation. In this framework, we investigate the influence of the material model on the numerical results and, in the case of the anisotropic laws, the importance of the collagen fibers on the overall mechanical behavior of the tissue. With this aim, we compare our numerical results by analyzing fluid dynamic indicators, vessel wall displacement, Von Mises stress, and deformations of the collagen fibers. Specifically, for an anisotropic model with collagen fiber recruitment at finite strains, we highlight the progressive activation and deactivation processes of the fibrous component of the tissue throughout the wall thickness during the cardiac cycle. The inclusion of collagen recruitment is found to have a substantial impact on the intramural stress, which will in turn impact the biological response of the intramural cells. Hence, the methodology presented here will be particularly useful for studies of mechanobiological processes in the healthy and diseased vascular wall. [ABSTRACT FROM AUTHOR]

Apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins. This protein has key functions in lipoprotein metabolism and its plasma concentration is inversely correlated with the incidence of atherosclerosis and cardiovascular diseases. There is an increasing need to develop methods for efficient production of recombinant apoA-I for using it in basic research or pharmacological therapy. An apoA-I variant lacking two amino acid residues at the N-terminus can be easily produced by bacterial expression. We report here the characterization of this variant comparing its properties with those of the protein isolated from human serum. The results validate the use of this variant in future assays and investigations. [ABSTRACT FROM AUTHOR]

An excess of intracellular free cholesterol (Chol) is cytotoxic, and its homeostasis is crucial for cell viability. Apolipoprotein A-I (apoA-I) is a highly efficient Chol acceptor because it activates complex cellular pathways that tend to mobilize and export Chol from cellular depots. We hypothesize that membrane composition and/or organization is strongly involved in Chol homeostasis. To test this hypothesis, we constructed a cell line overexpressing stearoyl coenzyme A (CoA) desaturase (SCD cells), which modifies plasma membrane (PM) composition by the enrichment of monounsaturated fatty acids, and determined this effect on membrane properties, cell viability, and Chol homeostasis. PM in SCD cells has a higher ratio of phospholipids to sphingomyelin and is slightly enriched in Chol. These cells showed an increase in the ratio of cholesteryl esters to free Chol; they were more resistant to Chol toxicity, and they exported more caveolin than control cells. The data suggest that cell functionality is preserved by regulating membrane fluidity and Chol exportation and storage. [ABSTRACT FROM AUTHOR]

Colorectal cancer is one of the most common cancers in developed countries. Increasing numbers of early stage colorectal cancers and precancerous adenomatous lesions, polypoidal type lesions, and flat and depressed type lesions can be visualised and treated endoscopically thanks to endoscopic ultrasonography, high magnification chromoendoscopy and other technical advances. Polypectomy is generally considered for protuberant lesions, with both sessile and pedunculate morphology, and endoscopic mucosal resection (EMR) is indicated for superficial, flat or depressed types of lesions. Endoscopic therapy for colonic adenoma with dysplasia and early colorectal cancer is more advantageous than the conventional operative treatment, in that it is a relatively non-invasive and less costly method. However, endoscopic therapy is completely ineffective in lesions with lymph node or distant metastasis. Therefore, it is becoming more and more important to understand the correct indications and limitations of endoscopic polypectomy/mucosectomy as well as complication rates and the correct follow-up schedule. [ABSTRACT FROM AUTHOR]

To investigate the presence of reduced bone mineral density (BMD) and to assess determinants of bone loss in rheumatoid arthritis, 45 female patients suffering from non-steroid treated rheumatoid arthritis were submitted to dual photon absorptiometry of the lumbar spine and to laboratory tests for calcium metabolism. The rheumatoid arthritis patients were divided into two groups according to anatomic grade and functional class; no abnormalities in calcium metabolism were defected whereas BMD was significantly lower in the third and fourth grade and in the third and fourth class patients ( P<0.005 versus controls, versus grades I and II and versus classes 1 and 2). BMD was significantly correlated with age ( P<0.001) and years postmenopausal ( P<0.01), but not with duration of disease. By multiple inear regression we derived an equation predictive of BMD. Osteoporosis in rheumatoid arthritis is observed even in non-corticosteroid treated patients; articular lesions with subsequent reduction in physical activity appear to play an important role in axial bone loss in rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

We prove that it is possible to associate to each infinitesimal model on a Euclidean vector space V a locally homogeneous Riemannian manifold. As an application, we characterize, in the space of the algebraic curvature tensors on V, the orbits which can occur for locally homogeneous Riemannian manifolds. [ABSTRACT FROM AUTHOR]

Some «natural» metrics on the tangent and on the sphere tangent bundle of Riemannian manifold are constructed and studied via the moving frame method. [ABSTRACT FROM AUTHOR]

Juxtaarticular osteoporosis is a recognized clinical feature in both rheumatoid arthritis (RA) and psoriatic arthritis (PA), while generalised osteopenia seems to be characteristic of RA only. To assess differences in bone turnover in the two forms of disease, we measured serum osteocalcin levels and other parameters of bone metabolism in two groups of female, ambulant, age-matched patients suffering from active RA or active PA and never treated with steroid therapy. Serum osteocalcin levels were significantly higher in RA patients than in PA patients (13.05±1.27 ng/ml vs 4.83±0.88 ng/ml; p<0.001), with a significant positive correlation between osteocalcin and serum alkaline phosphatase in both groups. These data suggest that bone turnover is higher in active RA than in active PA. Juxtaarticular osteoporosis could be mediated by local disease mechanisms both in RA and in PA, while factors specifically related to active RA seem to determine a more generalized impairment of bone turnover. [ABSTRACT FROM AUTHOR]