Low-Cost Predictors for Liver Function and Clinical Outcomes after Sustained Virological Response in Patients with HCV-Related Cirrhosis and Thrombocytopenia.

Background and Objectives: To find low-cost markers that can identify the hepatitis C virus cirrhotic patients that are at risk for long-term severe adverse liver effects (ascites, ascites or upper gastrointestinal bleeding, hepatocellular carcinoma), after treatment. There is established evidence for the benefits of treating hepatitis C virus cirrhotic patients, but there is still some need for clarification concerning the real impact on the long-term evolution after achieving sustained virological response; there is no general consensus in the literature about identifying the patients that do not improve post-treatment. Materials and Methods: Our retrospective analysis investigated the long-term (2 years) evolution of 46 patients with cirrhosis with thrombocytopenia, previously infected with VHC, treated and who obtained an SVR after DAA treatment. Results: Despite the overall improvement, 8.7% patients developed hepatocellular carcinoma and 6.5% patients ascites/upper GI bleeding. We found that FIB-4, MELD and AFP changes at 1 year were the most significant predictors for these outcomes. Additionally, a drop in leukocyte count after 1 year seemed to indicate a risk for hepatocellular carcinoma, but this was not consistent. Conclusions: It might be beneficial to intensify the surveillance for post-treatment adverse liver effects for the patients with these marker changes at 1 year.

Biomaterials Adapted to Vat Photopolymerization in 3D Printing: Characteristics and Medical Applications.

Along with the rapid and extensive advancements in the 3D printing field, a diverse range of uses for 3D printing have appeared in the spectrum of medical applications. Vat photopolymerization (VPP) stands out as one of the most extensively researched methods of 3D printing, with its main advantages being a high printing speed and the ability to produce high-resolution structures. A major challenge in using VPP 3D-printed materials in medicine is the general incompatibility of standard VPP resin mixtures with the requirements of biocompatibility and biofunctionality. Instead of developing completely new materials, an alternate approach to solving this problem involves adapting existing biomaterials. These materials are incompatible with VPP 3D printing in their pure form but can be adapted to the VPP chemistry and general process through the use of innovative mixtures and the addition of specific pre- and post-printing steps. This review's primary objective is to highlight biofunctional and biocompatible materials that have been adapted to VPP. We present and compare the suitability of these adapted materials to different medical applications and propose other biomaterials that could be further adapted to the VPP 3D printing process in order to fulfill patient-specific medical requirements.

Temporal Instabilities in Amblyopic Perception: A Quantitative Approach.

The purpose of this study is to quantify the temporal characteristics of spatial misperceptions in human amblyopia. Twenty-two adult participants with strabismus, strabismic, anisometropic, or mixed amblyopia were asked to describe their subjective percept of static geometrical patterns with different spatial frequencies and shapes, as seen with their non-dominant eye. We generated digital reconstructions of their perception (static images or movies) that were subsequently validated by the subjects using consecutive matching sessions. We calculated the Shannon entropy variation in time for each recorded movie, as a measure of temporal instability. Nineteen of the 22 subjects perceived temporal instabilities that can be broadly classified in two categories. We found that the average frequency of the perceived temporal instabilities is ∼1 Hz. The stimuli with higher spatial frequencies yielded more often temporally unstable perceptions with higher frequencies. We suggest that type and amount of temporal instabilities in amblyopic vision are correlated with the etiology and spatial frequency of the stimulus.

Novel insights into the antiproliferative effects and synergism of quercetin and menadione in human leukemia Jurkat T cells.

The flavonoid quercetin and menadione (vitamin K3) are known as potent apoptogens in human leukemia Jurkat T cells. We explored some underlying mechanisms and the potential relevance of the combination quercetin-menadione for clinical applications. In acute treatments, quercetin manifested a strong antioxidant character, but induced a transient loss of Δψm, likely mediated by opening of the mitochondrial permeability transition pore. After removal of quercetin, persistent mitochondrial hyperpolarization was generated via stimulation of respiratory Complex I. In contrast, menadione-induced Δψm dissipation was only partially and transiently reversed after menadione removal. Results indicate that Ca(2+) release is a necessary event in quercetin-induced cell death and that the survival response to quercetin is delineated within 1h from exposure. Depending on dose, the two agents exhibited either antagonistic or synergistic effects in reducing clonogenicity of Jurkat cells. 24-h combinatorial regimens at equimolar concentrations of 10-15 µM, which are compatible with a clinically achievable (and safe) scheme, reduced cell viability at efficient rates. Altogether, these findings support the idea that the combination quercetin-menadione could improve the outcome of conventional leukemia therapies, and warrant the utility of additional studies to investigate the therapeutic effects of this combination in different cellular or animal models for leukemia.

Mitochondrial respiratory complex I probed by delayed luminescence spectroscopy.

The role of mitochondrial complex I in ultraweak photon-induced delayed photon emission [delayed luminescence (DL)] of human leukemia Jurkat T cells was probed by using complex I targeting agents like rotenone, menadione, and quercetin. Rotenone, a complex I-specific inhibitor, dose-dependently increased the mitochondrial level of reduced nicotinamide adenine dinucleotide (NADH), decreased clonogenic survival, and induced apoptosis. A strong correlation was found between the mitochondrial levels of NADH and oxidized flavin mononucleotide (FMNox) in rotenone-, menadione- and quercetin-treated cells. Rotenone enhanced DL dose-dependently, whereas quercetin and menadione inhibited DL as well as NADH or FMNox. Collectively, the data suggest that DL of Jurkat cells originates mainly from mitochondrial complex I, which functions predominantly as a dimer and less frequently as a tetramer. In individual monomers, both pairs of pyridine nucleotide (NADH/reduced nicotinamide adenine dinucleotide phosphate) sites and flavin (FMN-a/FMN-b) sites appear to bind cooperatively their specific ligands. Enhancement of delayed red-light emission by rotenone suggests that the mean time for one-electron reduction of ubiquinone or FMN-a by the terminal Fe/S center (N2) is 20 or 284 µs, respectively. All these findings suggest that DL spectroscopy could be used as a reliable, sensitive, and robust technique to probe electron flow within complex I in situ.

Quercetin and epigallocatechin-3-gallate effect on the anisotropy of model membranes with cholesterol.

Cell membrane fluidity, which can be altered by oxidative stress, plays an important role in the cell physiology. Flavonoids are among the most studied food substances that prevent and/or reduce oxidative stress, but their action mechanisms are far from being understood. We performed a study on the effect of quercetin and epigallocatechin-3-gallate on 2-Dimyristoyl-sn-glycero-3-phosphocholine small unilamellar vesicles (SUVs) with different amounts of cholesterol, using Laurdan as a fluorescent probe, to put into evidence the perturbations of the phospholipid membrane fluidity and local lipid order in an attempt to decipher the action mechanism of the flavonoids at the cell membrane level. Results indicate that polyphenols modulate the transition from the gel phase to the liquid crystalline phase of SUVs in all studied membranes. SUVs with cholesterol have by themselves higher phase transition temperature and the presence of polyphenols stabilizes further the membrane. Quercetin has a dose-dependent effect on the fluidity and local order of the lipid membranes, whilst epigallocatechin-3-gallate action is not dose-dependent, the differences being attributable to the hydrophobic/hydrophilic character of the substances. The findings are discussed within the frame of earlier reports on the effect of polyphenols on artificial membranes.

Diffusion-convection effects on drug distribution at the cell membrane level in a patch-clamp setup.

We present a model-based method for estimating the effective concentration of the active drug applied by a pressure pulse to an individual cell in a patch-clamp setup, which could be of practical use in the analysis of ligand-induced whole-cell currents recorded in patch-clamp experiments. Our modelling results outline several important factors which may be involved in the high variability of the electric response of the cells, and indicate that with a pressure pulse duration of 1s and diameter of the perfusion tip of 600 µm, elevated amounts of drug can accumulate locally between the pipette tip and the cell. Hence, the effective agonist concentration at the cell membrane level can be consistently higher than the initial concentration inside the perfusion tubes. We performed finite-difference and finite-element simulations to investigate the diffusion/convection effects on the agonist distribution on the cell membrane. Our model can explain the delay between the commencement of acetylcholine application and the onset of the whole-cell current that we recorded on human rhabdomyosarcoma TE671 cells, and reproduce quantitatively the decrease of signal latency with the concentration of agonist in the pipette. Results also show that not only the geometry of the bath chamber and pipette tip, but also the transport parameters of the diffusive and convective phenomena in the bath solution are determinant for the amplitude and kinetics of the recorded currents and have to be accounted for when analyzing patch-clamp data.

Temporal instability in amblyopic vision: relationship to a displacement map of visual space.

PURPOSE: To investigate the relationship between the subjectively experienced misperceptions and the objectively determined two-dimensional spatial displacement maps in subjects with strabismic and anisometropic amblyopia. METHODS: Seventeen experimental subjects were asked to describe and sketch their perception of simple geometric pattern, as perceived through their amblyopic eyes. A subgroup of 15 subjects participated in a psychophysical experiment, in which the two-dimensional displacement maps were determined by asking the subjects to reconstruct, point-by-point, memorized circles of different radii. The results of these displacement maps were related to the clinical characteristics and the perceptual descriptions of the same subjects. RESULTS: Twelve of the 17 investigated subjects experienced spatial distortions; six subjects perceived temporal instabilities, either in addition, or in the absence of spatial distortions. Objectively determined spatial displacement and spatial uncertainty were significantly larger in subjects with a history of strabismus and a deep acuity loss than in subjects with refractive etiology and a mild acuity loss. Subjects experiencing temporal instability showed more spatial uncertainty in the amblyopic eye than did subjects with a stable perception. CONCLUSIONS: These results suggest that a history of strabismus and a deep amblyopia are more likely to be associated with temporal misperceptions than a refractive etiology and a mild acuity loss. A temporally unstable perception may be related to a more profound disorganization of the central neural pathways connected to the amblyopic eye.

Patterns of spatial distortions in human amblyopia are invariant to stimulus duration and instruction modality.

We investigated the patterns of two-dimensional spatial distortions in human amblyopia, using three different psychophysical mapping procedures. Strabismic and strabismic-anisometropic amblyopes showed consistent distortions, consisting in enlargement, shrinkage, or torsion of portions of the tested visual field. Purely anisometropic amblyopes and strabismics with alternating fixation showed increased spatial uncertainty, but no consistent distortions. For all groups of subjects, there was a very good correspondence between the patterns of distortion obtained with the three methods. We conclude that the spatial distortions are robust across different procedures. They might reflect a genuine rearrangement of the cortical topography as a result of strabismus.

An automated method for creating simulated distorted images in amblyopic vision.

Spatial distortions in amblyopic vision can be captured by subjective reports or by a point-by-point mapping of the central part of the visual field. In this study, we developed a series of algorithms that provide a fine-grain mapping of the amblyopic percept. These algorithms can be applied to any real-world image. The images created based on these algorithms can be compared with the subjective percept of each amblyope.

Spatial and temporal misperceptions in amblyopic vision.

The aim of this study was to investigate the spatial and temporal distortions that occur in strabismic and anisometropic amblyopic vision. Twelve subjects with strabismic (n = 4), anisometropic (n = 4), mixed amblyopia (n = 3) and bilateral refractive amblyopia (n = 1) were asked to describe and sketch their subjective percept of different geometrical patterns, as seen with their amblyopic eye. Based on their descriptions, computer-animated patterns were generated, which were then validated by the subjects. Both spatial distortions and temporal instability were perceived mainly by strabismic and strabismic-anisometropic amblyopes. Temporal instability occurred mainly at high spatial frequencies. Our data suggest that strabismus, in addition to amblyopia, is needed to elicit significant spatial and temporal distortions. The occurrence of these distortions may be related to the early history of each subject.