Model for a one-step plasma treatment device: feasibility of cholesterol removal

A self-contained plasmapheresis device based on Starling flow has been proposed. A computer model was developed to describe the device performance, and a device using conventional cellulose tri-acetate (CTA) fibers was modeled. Predicted pressure drops and ultrafiltration flow agreed well with measurements using bovine blood in prototype devices made with CTA fibers. The model predicted the expected Starling flow and predicted the observed high hematocrit region near the fiber wall and a layer of packed red cells on the wall. Typically, 15% of the ultrafiltration flow occurred in the first 2-3% of the fiber length where no packed cell layer was present. The entrance header was predicted to cause lower blood pressures in the peripheral fibers, producing a net plasma migration from the central to the peripheral fibers. As an example application for this device, the computer model was used to assess the feasibility of reducing LDL-cholesterol in patients. The use of sequential 1 hour treatments by a modified device was predicted to reduce the cholesterol in a standard man from 200 mg% to 150 mg% in less than 3 hours.     

The effects of nutritional habits on leucite-based ceramic repaired with nanohybrid composites

The purpose of the present in vitro study was to evaluate the effects of nutritional habits (various liquids) on the color change and early repair bond strength of a leucite-based ceramic repaired with different contents of nanohybrid composite resins currently used by the clinicians. Ninety-six IPS-Empress CAD ceramic samples were obtained with low-speed diamond saw. For all samples same repair method was performed. Samples were divided into groups according to four nanohybrid composite resins used as a repair material: Tetric-N-Ceram Bulk Fill, Filtek Z550, Clearfil-Majesty Esthetic, Bisco-Aelite Aesthetic Enamel (n?=?24). Composite resins were applied on ceramic surface and polymerized (40?sec). After waiting for 24?h, samples were divided into three subgroups according to liquid types: pomegranate-flavored mineral water, salad dressing, and distilled water (n?=?8). Before and after immersion the samples in the various liquids, color measurements were calculated (24?h). Then, shear bond strength was tested with an universal testing machine.For the statistical analyses two-way ANOVA, Tukey HSD, Spearman's correlation tests were used at a significance of p?≤?0.05. Nanohybrid composites, liquids (p?≤?0.001); correlation between nanohybrid composites and liquids (p?≤?0.006) had statistically significant impacts on the color change values. Nanohybrid composites (p?≤?0.017) and correlation between nanohybrid composites and liquids (p?≤?0.004) had statistically significant impacts on the shear bond strength values. There was not any statistically significant correlation between color change and shear bond strength (p?>?0.05). When a composite resin is selected as a repair material, nutritional habits of the patient should be taken into consideration. Although hydrophilic monomer type of a composite material is a more predominant factor associated with color change, filler weight has the same predominant effect on shear-bond strength.     

Development of environmentally friendly antifouling paints using biodegradable polymer and lower toxic substances

The development of new antifouling coatings with respect to the marine environment is actually crucial. The aim of the present work is to concept an erodible paint formulated with biodegradable polyester as binders and which combines two modes of prevention: chemical and physical repelling of biofouling. This system is principally dedicated to disturb durable settlement of microfouling. Each component was chosen according to its specific properties: chlorhexidine is a bisdiguanide antiseptic with antibacterial activity, zinc peroxide is an inorganic precursor of high instable entities which react with seawater to create hydrogen peroxide, Tween 85 is a non ionic surfactant disturbing interactions between colonizing organisms and surface. Obtained results highlighted the interest on mixing such molecules to obtain a promising coating with lower toxicity than traditional systems.     

Adjunct effect of loratadine in the treatment of acute sinusitis in patients with allergic rhinitis

Recently, it has been recognized that cell-bound heparan sulfate (HS) proteoglycans (HSPG) are able to bind and subsequently initiate degradation of lipoproteins. Two mediators of lipoprotein catabolism, both with HS binding capacity, lipoprotein lipase (LPL) and apolipoprotein E (apoE), are involved in this process. This mechanism is known as the secretion-capture process of apoE. Lipoprotein(a) [Lp(a)] was shown to have a strong binding capacity to cell-associated HSPG. This binding capacity was increased by LPL addition. We investigated the effects of recombinant apoE (r-apoE) enrichment of Lp(a) on the binding to HS. Lp(a), isolated by ultracentrifugation and gel filtration, was incubated with r-apoE and reisolated by ultracentrifugation, resulting in r-apoE-enriched Lp(a). ApoE-enriched Lp(a) and control Lp(a) were coated to microtiter plates. The capacity to bind biotin-conjugated HS (b-HS) in the presence or absence of inactivated bovine LPL was studied. R-apoE-enriched Lp(a) showed increased b-HS binding capacity versus control Lp(a). Addition of LPL resulted in an increased b-HS binding capacity of both control and r-apoE-enriched Lp(a). To investigate whether binding of Lp(a) to endothelial cell HSPG occurred in vivo, 39 volunteers were injected with heparin (50 U/kg) and plasma lipid and Lp(a) levels were determined before and 20 minutes after heparin injection. No significant increase in plasma Lp(a) concentrations was found. The results showed that Lp(a) can be enriched with apoE and that this resulted in increased LPL-enhanced binding to HSPG. From the in vitro studies, it can be concluded that the secretion-capture process of apoE is a possible catabolic route for Lp(a). However, whether this also occurs in vivo remains to be confirmed.     

Solution structure of Lqh-8/6, a toxin-like peptide from a scorpion venom--structural heterogeneity induced by proline cis/trans isomerization

Lqh-8/6 is a minor fraction isolated from the venom of the scorpion Leiurus quinquestriatus hebraeus. Here we describe the purification, amino acid sequencing and solution structure determination by NMR and molecular modeling of this peptide. Lqh-8/6 is a small polypeptide (38 residues) which contains 8 half-cystines and is highly similar to another venom component, chlorotoxin. Standard homonuclear methods were used to sequentially assign the proton NMR spectra and to collect spatial restraints for structure determination. Two populations, identified early in the assignment step, are in slow interconversion on the NMR timescale. The two conformers were shown to originate from a cis/trans peptidyl-prolyl isomerization. Using a distance geometry program and simulated annealing protocol under the NMR restraints we obtained 10 final structures for the major conformation (trans isomer). None of the structures showed NOE violations larger than 0.05 nm, and the rmsd value relative to the mean structure (considering the main chain atoms in well-defined secondary structure) is 0.07 nm. The three-dimensional structure contains a short alpha-helix strapped on a small antiparallel beta-strand and an N-terminal extended fragment. The sequence/structure and structure/function relationships of the new scorpion toxin-like peptide are discussed in the context of the present structure determination. This toxin shows a stable, highly populated cis conformer of a peptidyl-prolyl peptide bond.     

Device induced thromboembolism in a bovine in vitro coronary stent model

The potential of a new bovine in vitro model to evaluate various aspects of device induced thromboembolism was studied using two test modes. First, the effect of an antithrombotic drug on stent induced thromboembolism was assessed. The antithrombotic potential of an antiplatelet agent was compared with that of the other conventional antithrombotic agents (aspirin, dipyridamole) used in the past with this in vitro model. Stent associated thrombus was assessed gravimetrically at the end of the experiment. Emboli were assessed continuously using a light scattering microemboli detection system. Second, the sensitivity of the model to flow induced thromboembolism was studied using a combination of surface roughness and stenosis. Thrombus was assessed visually, and emboli were assessed as described earlier. The results show that 1) this in vitro model is sensitive to the action of antithrombotic drugs, and to the effect of hemodynamics on thromboembolism; 2) the antiplatelet drug used in this study was effective in attenuating thromboembolism; 3) a stenosis in combination with roughness produced more emboli than roughness alone; and 4) the model was useful for the study of physical and biochemical aspects of thromboembolism.