• Johnsen Malik posted an update 4 hours, 23 minutes ago

    BACKGROUND Remodeling of the uterine spiral arteries and blood vessels within the placenta allows delivery of nutrients to the growing utero-fetal-placental unit. While abnormal remodeling of these vessels is thought to play an important role in syndromes including intrauterine growth restriction and preeclampsia, there are a lack of studies that have quantified vascular remodeling in normal pregnant rats. Thus, the purpose of this study was to quantify time-dependent remodeling of the utero-placental vasculature during late gestation in normal pregnant rats. METHODS Timed-pregnant Sprague-Dawley rats were used. Gestational days of 14 and 19 were chosen because this when a large amount of fetal and placental growth occurs. A combined method of perfusion-casting and 3D micro-computed tomography were utilized to construct ex-vivo utero-placental vasculature images. RESULTS Significant spiral artery remodeling occurred between days 14 and 19. Vessel density shifted away from a distribution of smaller to larger diameters by day 19. Total spiral artery area and average diameter were increased by day 19. Moreover, branching and tortuosity of the spiral arteries were greater by day 19. In rodents, spiral arteries feed into the central canal vessels that funnel to sites of exchange. Canal vessel area and diameter were increased by day 19. CONCLUSIONS Our study supports a quantitative method to examine the placental vasculature showing that significant vascular remodeling occurs during late gestation in the utero-placental-fetal unit of the normal pregnant rat. This method may serve as a tool to investigate fundamental pathophysiological mechanisms underlying placental-related diseases in rat models. Human hair is a readily available source for hair protein-based biomaterial and is increasingly explored as an alternative to existing hemostatic materials. The hair protein is a complex mixture of multiple proteins, which are preferably extracted at relatively high temperatures (50-90 °C) for increasing protein yields. However, the effect of processing temperature on the hemostatic property of the hair derived proteins are not yet well-understood. The objective of the current study was to characterize the influence of thermal treatments (37 °C, 50 °C, 75 °C, 80 °C, and 90 °C) on the (i) secondary structure of different fractions of hair proteins including keratin (40-65 kDa) and keratin-associated proteins (KAPs, 6-30 kDa), and (ii) their capability to precipitate the soluble fibrinogen in an in vitro fibrin clotting assay. Our results indicated that the thermal treatments induced changes to the helical contents of hair-derived protein extracts and also increased the precipitation amount and rate of soluble fibrinogen. While further studies are required to better understand the exact role of hair protein fractions on the coagulation process, the current research suggests that the hair proteins extracted under relatively high temperatures is a prerequisite approach for improving the hemostatic property of human hair-derived proteins. Trivalent actinides such as Cm(III) are able to occupy natural Ca(II) binding sites in biological systems. For this investigation, we studied the formation of aqueous Cm(III) complexes with S-layer proteins by time-resolved laser-induced fluorescence spectroscopy (TRLFS). S-layer proteins serve as protective biointerfaces in bacteria and archaea against the surrounding solution. Experimental assays were performed at a fixed total concentration of Cm(III) (0.88 μM) using an S-layer protein (5 g/L / 39.6 μM) at varying pH levels (2.0-9.0), as well as several types of S-layer proteins of L. NVP-BKM120 sphaericus JG-A12. Based on resulting luminescence spectra and lifetime data, specific and unspecific binding sites could be distinguished. Notably, specific Cm(III) binding to S-layer proteins was confirmed by the appearance of a sharp emission band at 602.5 nm, combined with a long lifetime of 310 μs. The high affinity of these specific binding sites was also verified using competing EDTA, wherein only a high EDTA concentration (40 μM) could efficiently remove Cm(III) from S-layer proteins. Development of porous silicon-based drug delivery systems for theranostics requires a precise control of their biodegradation. Thus, we propose a model for the biodegradation of porous silicon nanoparticles (PSi NPs) based on a diffusion equation combined with Nernst-Brunner mass transfer equation describing the dissolution of silicon and formation of silicic acid (SA). The spatiotemporal distributions of PSi NP porosity and SA concentration were calculated. The model was successfully applied to fitting a great variety of experimental data on more than 10 factors influencing the PSi NP biodegradation kinetics, such as the morphology of PSi NPs, surface composition, properties of surrounding media and protective coating layer. Two principal regimes were found out for systems with either diffusion or dissolution dominating over each other. The results of simulations revealed the values of several important parameters, which are hard to be measured experimentally. Dental materials are susceptible to dental plaque formation, which increases the risk of biofilm-associated oral diseases. Physical-chemical properties of dental material surfaces can affect salivary pellicle formation and bacteria attachment, but relationships between these properties have been understudied. We aimed to assess the effects of surface properties and adsorbed salivary pellicle on Streptococcus gordonii adhesion to traditional dental materials. Adsorption of salivary pellicle from one donor on gold, stainless steel, alumina and zirconia was monitored with a quartz crystal microbalance with dissipation monitoring (QCM-D). Surfaces were characterized by X-ray photoelectron spectroscopy, atomic force microscopy and water contact angles measurement before and after pellicle adsorption. Visualization and quantification of Live/Dead stained bacteria and scanning electron microscopy were used to study S. gordonii attachment to materials with and without pellicle. The work of adhesion between surfaces and bacteria was also determined.