Portable Alkaline Phosphatase-Hydrogel Platform: From Enzyme Characterization to Phosphate Sensing.

Here, we present a study on the incorporation and characterization of the enzyme alkaline phosphatase (ALP) into a three-dimensional polymeric network through a green protocol to obtain transparent hydrogels (ALP@AETA) that can be stored at room temperature and potentially used as a disposable biosensor platform for the rapid detection of ALP inhibitors. For this purpose, different strategies for the immobilization of ALP in the hydrogel were examined and the properties of the new material, compared to the hydrogel in the absence of enzyme, were studied. The conformation and stability of the immobilized enzyme were characterized by monitoring the changes in its intrinsic fluorescence as a function of temperature, in order to study the unfolding/folding process inside the hydrogel, inherently related to the enzyme activity. The results show that the immobilized enzyme retains its activity, slightly increases its thermal stability and can be stored as a xerogel at room temperature without losing its properties. A small portion of a few millimeters of ALP@AETA xerogel was sufficient to perform enzymatic activity inhibition assays, so as a proof of concept, the device was tested as a portable optical biosensor for the detection of phosphate in water with satisfactory results. Given the good stability of the ALP@AETA xerogel and the interesting applications of ALP, not only in the environmental field but also as a therapeutic enzyme, we believe that this study could be of great use for the development of new devices for sensing and protein delivery.

Silica/Proteoliposomal Nanocomposite as a Potential Platform for Ion Channel Studies.

The nanostructuration of solid matrices with lipid nanoparticles containing membrane proteins is a promising tool for the development of high-throughput screening devices. Here, sol-gel silica-derived nanocomposites loaded with liposome-reconstituted KcsA, a prokaryotic potassium channel, have been synthesized. The conformational and functional stability of these lipid nanoparticles before and after sol-gel immobilization have been characterized by using dynamic light scattering, and steady-state and time-resolved fluorescence spectroscopy methods. The lipid-reconstituted KcsA channel entrapped in the sol-gel matrix retained the conformational and stability changes induced by the presence of blocking or permeant cations in the buffer (associated with the conformation of the selectivity filter) or by a drop in the pH (associated with the opening of the activation gate of the protein). Hence, these results indicate that this novel device has the potential to be used as a screening platform to test new modulating drugs of potassium channels.

Effectiveness of an intervention in multicomponent exercise in primary care to improve frailty parameters in patients over 70 years of age (MEFAP-project), a randomised clinical trial: rationale and study design.

BACKGROUND: Physical activity may reverse frailty in the elderly, but we encounter barriers to the implementation of exercise programs in this population. Our main aim is to evaluate the effect of a multicomponent physical activity program, versus regular medical practice, on reverting pre-frailty status among the elderly, 12 months post-intervention. METHODS: Randomized parallel group multicenter clinical trial located in primary care setting, among non-dependent and pre-frail patients > 70 years old, including 190 patients (95 intervention, 95 control group). INTERVENTION: Multicomponent physical activity program (MEFAP, for its acronym in Spanish) with twelve 1.5 h-weekly sessions comprised of: 1. Informative session; 2. Exercises for improving aerobic resistance, muscle strength, propioception-balance and flexibility; and 3. Handing out of at-home exercise chart (twice/week). Main variable: pre-frailty according to the Fried phenotype. Secondary variables: sociodemographic, clinical and functional variables; exercise program adherence, patient satisfaction with the program and quality of life. We will perform an intention-to-treat analysis by comparing the retrogression from pre-frailty (1 or 2 Fried criteria) to robust status (0 Fried criteria) by the end of the intervention, 6 months and 12 months post-intervention. The accumulated incidence in each group will be calculated, as well as the relative risk (RR) and the number needed to treat (NNT) with their corresponding 95% confidence intervals. Protocol was approved by the Ethics Committee Hospital la Paz. DISCUSSION: Within the context of regular clinical practice, our results will provide evidence regarding the effects of exercise interventions on frailty among pre-frail older adults, a key population given their significant potential for functional, physical, and mental health improvement. TRIAL REGISTRATION: NCT03568084 . Registered 26 June 2018. Date of enrollment of the first participant to the trial: July 2nd 2018.

Selective recognition and imaging of bacterial model membranes over mammalian ones by using cationic conjugated polyelectrolytes.

The development of new tools for the detection and fluorescence imaging of bacteria is of great interest in clinical diagnosis and food and environmental safety. In this work, we have explored the ability of two cationic fluorene-based conjugated polyelectrolytes, HTMA-PFP and HTMA-PFNT, emitting in the blue and red spectral regions respectively, to selectively label bacterial over mammalian cells. With this end in view, vesicles with lipid compositions mimicking those of bacterial or mammalian membranes were used as model membranes to explore the interaction of the polyelectrolytes with both systems in samples containing either a single type of vesicle or a mixture of both. Changes in the intrinsic fluorescence of HTMA-PFP and HTMA-PFNT were used to quantify the affinity of these polyelectrolytes for the model lipid membranes, while quenching experiments were employed to evaluate their selectivity to each lipid system. In addition, fluorescence microscopy experiments were performed to check the ability of polyelectrolytes to label the vesicles without affecting their integrity. Results showed that both polyelectrolytes rapidly label the model vesicles but they preferentially bind to those mimicking bacterial membranes, HTMA-PFNT being much more selective to this type of membranes than HTMA-PFP. Preliminary experiments with living bacteria and mammalian cells support this conclusion, showing that in samples with both types of cells together, HTMA-PFNT only images the bacterial cells, thus evidencing its potential use for the selective recognition and imaging of bacterial presence.

Enhanced efficiency of AlGaInP disk laser by in-well pumping.

The performance of a 665-nm GaInP disk laser operated continuous-wave at 15°C both in-well-pumped at 640 nm and barrier pumped at 532 nm is reported. The efficiency with respect to the absorbed power was enhanced by 3.5 times when using a 640-nm pump instead of a 532-nm pump. In-well pumping which is based on the absorption of the pump photons within the quantum-well heterostructures of the gain region instead of short-wavelength absorption in the barrier and spacer regions reduces the quantum defect between pump and laser photon and hence the heat generation. A slope efficiency of 60% with respect to the absorbed pump power was obtained by in-well pumping at 15°C. Continuous-wave laser operation was further demonstrated at heat sink temperatures of up to 55°C. Both the measurement of photoluminescence and COMSOL simulation show that the overall heat load in the in-well pumped laser is smaller than in the barrier-pumped laser. These results demonstrate the potential of optical in-well pumping for the operation of red AlGaInP disk lasers if combined with means for efficient pump-light absorption.

Bronchoalveolar Lavage Fluid Cytology of Deployed Military Personnel With Chronic Respiratory Symptoms From the STAMPEDE III Study.

INTRODUCTION: Deployed military personnel may be at risk for developing acute and chronic lung disease. Prior studies of this patient population have revealed that unexplained exertional dyspnea is the most common diagnosis despite an extensive evaluation. There is a concern that an occult disorder may be affecting this population. This study evaluated the role for bronchoalveolar lavage (BAL) fluid analysis in the evaluation of chronic deployment-associated dyspnea. MATERIALS AND METHODS: Military personnel who reported chronic respiratory symptoms were evaluated as part of the Study of Active Duty Military for Pulmonary Disease Related to Environmental Deployment Exposures III study. Participants underwent bronchoscopy with BAL as part of a standardized evaluation. RESULTS: A total of 308 patients with a mean age of 38 ± 8.6 years underwent bronchoscopy with BAL. BAL cell-count percentages of macrophages, lymphocytes, neutrophils, and eosinophils were: 76.2 ± 17.0%, 16.3 ± 13.4%, 6.6 ± 8.9%, and 0.9 ± 3.2%, respectively. There was no clear differentiation between groups based on increases in lymphocyte counts (P = .640), although lymphocyte values were more elevated (21.4 ± 12.1%) in the interstitial lung disease category. Neutrophil counts (6.6 ± 8.9%) were elevated compared to the reported normal reference values and were increased in the isolated pulmonary function test abnormality (9.4 ± 11.6%), large airway disorder (10.0 ± 7.5%), miscellaneous (10.9 ± 20.2%), and obstructive lung disease (11.0 ± 15.6%) groups. Eosinophil counts were within normal limits (0.9 ± 3.2%) and showed no differences between groups (P = .545); asthma patients trended higher (1.6 ± 5.7%). BAL counts for the exertional dyspnea group were within normal reference values and showed no differences from the entire cohort. CONCLUSIONS: The addition of BAL cytology did not help differentiate those patients with unexplained dyspnea from other etiologies.

Use of the conjugated polyelectrolyte poly{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} bromide (HTMA-PFP) as a fluorescent membrane marker.

The present work explores the potential use of the conjugated cationic polyfluorene {[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} bromide (HTMA-PFP) as a fluorescent membrane marker. To this end, the interaction of the polyelectrolyte with anionic model membranes has been investigated using different biophysical approaches. High affinity interaction was confirmed through alterations in the fluorescence spectrum of HTMA-PFP and by Förster resonance energy transfer (FRET) analysis. Quenching data indicate that once HTMA-PFP interacts with the membrane, it penetrates in the hydrophobic core embedded in the lipid bilayer where it presents high fluorescence quantum yield and photostability. Leakage experiments and dynamic light scattering (DLS) measurements show that the integrity of the lipid vesicles is maintained after polymer incorporation since no vesicle fusion or decomposition into small fragments is detectable. This conclusion is supported by fluorescence microscopy images, which confirm that polyelectrolyte interacts with the vesicle, labeling the lipid membrane without altering its morphology. Further experiments performed as a function of temperature indicate that the polymer is accommodated in the membrane without inducing significant loss of lipid cooperativity and without altering the packing of lipids within the bilayer. Finally, results show that polyelectrolyte fluorescence is sensitive to the large structural changes taking place in the lipid bilayer at the lipid phase transition. All these results confirm the ability of HTMA-PFP to visualize membrane structures and to monitor membrane processes.

Formation and characterization of stable fluorescent complexes between neutral conjugated polymers and cyclodextrins.

Solubilisation and stabilization of conjugated polymers, CPs, in aqueous media remains a challenge for many researches trying to extend the biological and environmental applications of this kind of polymers. A number of different alternatives have been considered to address this problem, which are mostly based on the enhancement of the macromolecule polarity, by appending hydrophilic side chains on the polymer backbone. In this work we have investigated a new strategy in which water solubilization is reached by external addition of classical cyclodextrins (α-, ß- and γ-CDs) to a solution of non-polar CPs. This strategy allows working with such polymers eliminating the need to synthesize new water-soluble species. The polymer selected for the study was poly-[9,9-bis(6'-bromohexyl-2,7-fluoren-dyil)-co-alt-(benzene-1,4-diy)], PFPBr(2), a polyfluorene previously synthesized in our laboratory. Results show that PFPBr(2) forms fluorescent complexes in aqueous media with ß-CD and γ-CD, and much less efficiently with α-CD, probably due to the small size of its cavity. The new PFPBr(2)/CD complexes are stable in time and in a large range of pH, however, at high concentration and temperature, they tend to aggregate and precipitate. In order to increase stabilization and minimize polymer aggregation, complexes were encapsulated inside the pores of silica glasses fabricated using the sol-gel process, obtaining transparent and fluorescent hybrid matrices which were stable in time and temperature. In addition, immobilization of the complexes allows an easy manipulation of the material, thus offering promising applications in the development of biological and chemical sensors.

Thermal unfolding and refolding of lysozyme in deep eutectic solvents and their aqueous dilutions.

The stability of hen's egg white lysozyme in different choline chloride-based pseudo-concentrated and neat deep eutectic solvents (DESs) has been studied by means of intrinsic fluorescence and CD spectroscopy. Thermal unfolding experiments carried out in non-diluted urea:choline chloride and glycerol:choline chloride eutectic solvents (UCCl-DES and GCCl-DES, respectively) showed the accumulation at certain temperatures of discrete, partially folded intermediates that displayed a high content of secondary structure and a disrupted tertiary structure. Reversibility of the unfolding process was incomplete in these circumstances, with the urea-based DES showing higher protein structure destabilization upon thermal treatment. On the other hand, aqueous dilution of the eutectic mixtures allowed the recovery of a reversible, two-state denaturation process. Lysozyme activity was also affected in neat and pseudo-concentrated GCCl-DES, with an increasing recovery of activity upon aqueous dilution, and full restoration after DES removal through extensive dialysis. These results suggest that protein interactions at room temperature are reversible and depend on the DES components and on the aqueous content of the original DES dilution.

Fluorescent Nanocomposite Hydrogels Based on Conjugated Polymer Nanoparticles as Platforms for Alkaline Phosphatase Detection.

This work describes the development and characterization of fluorescent nanocomposite hydrogels, with high swelling and absorption capacity, and prepared using a green protocol. These fluorescent materials are obtained by incorporating, for the first time, polyfluorenes-based nanoparticles with different emission bands-poly[9,9-dioctylfluorenyl-2,7-diyl] (PFO) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(1,4-benzo-{2,1,3}-thiadiazole)] (F8BT)-into a three-dimensional polymeric network based on polyacrylamide. To this end, two strategies were explored: incorporation of the nanoparticles during the polymerization process (in situ) and embedment after the hydrogel formation (ex situ). The results show that the combination of PFO nanoparticles introduced by the ex situ method provided materials with good storage stability, homogeneity and reproducibility properties, allowing their preservation in the form of xerogel. The fluorescent nanocomposite hydrogels have been tested as a transportable and user-friendly sensing platform. In particular, the ability of these materials to specifically detect the enzyme alkaline phosphatase (ALP) has been evaluated as a proof-of-concept. The sensor was able to quantify the presence of the enzyme in an aqueous sample with a response time of 10 min and LOD of 21 nM. Given these results, we consider that this device shows great potential for quantifying physiological ALP levels as well as enzyme activity in environmental samples.

Correlation of Impulse Oscillometry with Spirometry in Deployed Military Personnel with Airway Obstruction.

INTRODUCTION: Evaluation of chronic respiratory symptoms in deployed military personnel has been conducted at Brooke Army Medical Center as part of the Study of Active Duty Military for Pulmonary Disease Related to Environmental Deployment Exposures III study. Although asthma and airway hyperreactivity have been the most common diagnoses, the clinical findings in these patients may be multifactorial. This study aims to evaluate the utility of impulse oscillometry (IOS) in diagnosing airway obstruction in patients undergoing multiple pulmonary function testing (PFT) studies. METHODS: Military personnel referred for deployed-related pulmonary symptoms underwent a standardized evaluation at Brooke Army Medical Center and Walter Reed National Military Medical Center over a 5-year span. Initial studies included laboratory tests, high-resolution computed tomography imaging, cardiac evaluation with electrocardiogram, and echocardiography. PFT consisted of full PFTs, forced inspiratory/expiratory pressures, post-spirometry bronchodilator testing, IOS, exhaled nitric oxide, and methacholine challenge testing. RESULTS: A total of 360 patients have completed an evaluation to date. In this cohort, 108 patients (30.0%) have evidence of obstruction by spirometry, whereas 74 (20.6%) had IOS values of both an R5 > 150% and X5 < -1.5. Only 32 (8.9%) had evidence of obstruction by both spirometry and IOS, whereas 210 (57.3%) had neither. A comparison among R5 (resistance at 5 Hz), R20 (resistance at 20 Hz), and X5 (reactance at 5 Hz) was performed in those individuals with and without spirometric obstruction. R5 (% predicted) was 156.2 ± 57.4% (obstruction) vs. 129.1 ± 39.6% (no obstruction) (P < .001); R20 (% predicted) was 138.1 ± 37.7% (obstruction) vs. 125.3 ± 31.2% (no obstruction) (P = .007); and X5 (cmH2O/L/s) was -1.62 ± 1.28 (obstruction) vs. -1.25 ± 0.55 (no obstruction) (P < .001). DISCUSSION: Impulse oscillometry has been advocated as a supplemental pulmonary function test to aid in the diagnosis of airway obstruction. The use of IOS has been primarily used in pediatrics and elderly populations as a validated tool to establish a diagnosis of airway obstruction but is limited in the adult population because of a well-validated set of reference values. Prior studies in adults have most often demonstrated a correlation with an elevated R5 > 150%, elevated resonant frequency, and a negative X5 < -1.5 or a decrease of 30 to 35% in R5 post-bronchodilator. CONCLUSION: Impulse oscillometry may serve as an adjunct to diagnosis but likely cannot replace a standard spirometric evaluation. Our study highlights the future utility for diagnosing early obstructive disease in the symptomatic individual.

Disposable Electrochemical Biosensor Based on the Inhibition of Alkaline Phosphatase Encapsulated in Acrylamide Hydrogels.

The present work describes the development of an easy-to-use portable electrochemical biosensor based on alkaline phosphatase (ALP) as a recognition element, which has been immobilized in acrylamide-based hydrogels prepared through a green protocol over disposable screen-printed electrodes. To carry out the electrochemical transduction, an electroinactive substrate (hydroquinone diphosphate) was used in the presence of the enzyme and then it was hydrolyzed to an electroactive species (hydroquinone). The activity of the protein within the matrix was determined voltammetrically. Due to the adhesive properties of the hydrogel, this was easily deposited on the surface of the electrodes, greatly increasing the sensitivity of the biosensor. The device was optimized to allow the determination of phosphate ion, a competitive inhibitor of ALP, in aqueous media. Our study provides a proof-of-concept demonstrating the potential use of the developed biosensor for in situ, real-time measurement of water pollutants that act as ALP inhibitors.

The Effect of Deployment on Pulmonary Function in Military Personnel With Asthma.

INTRODUCTION: Military personnel with a diagnosis of asthma report increased respiratory symptoms in the deployment and post-deployment periods. The long-term effect of deployment on pulmonary function in this population is unknown. This study sought to determine the effect of deployment on post-deployment pulmonary function in active duty military personnel with asthma. MATERIALS AND METHODS: A retrospective chart review of active duty military personnel with deployment to southwest Asia and an ICD-9 diagnosis of asthma with documented pre- and post-deployment spirometry was performed. RESULTS: A total of 642 active duty individuals with a diagnosis of asthma and documented spirometry with deployment to southwest Asia between 2006 and 2015 were identified. Of these, 76 individuals were identified with pre- and post-deployment spirometry. There was no significant change in the post-deployment forced expiratory volume at 1 second (% predicted), from 86.0 ± 14.8 to 87.6 ± 14.4 (P = .30). There was no significant change in post-deployment forced vital capacity (% predicted), from 93.8 ± 12.4 to 94.9 ± 12.1 (P = .42). The absolute change in forced expiratory volume at 1 second (L) after bronchodilator administration was decreased from pre-deployment to post-deployment (+0.31 ± 0.26 to +0.16 ± 0.23; P = .02). CONCLUSIONS: There was no significant post-deployment change in spirometry in this military population with asthma deployed to southwest Asia. These findings suggest that deployment itself is not associated with any short-term deleterious effect on post-deployment spirometric measures of lung function in many military personnel with asthma.

A Case of Heyde's Syndrome With Subvalvular Aortic Stenosis.

Heyde's syndrome is a constellation of severe aortic stenosis, gastrointestinal arteriovenous malformations (AVMs), and an acquired von Willebrand type 2A coagulopathy resulting in moderate-to-severe gastrointestinal bleeding. Additional cardiac lesions have been observed to cause Heyde's syndrome including aortic regurgitation, mitral regurgitation, aortic/mitral valve prosthetic dysfunction, ventricular septal defects, hypertrophic cardiomyopathy, left ventricular assist devices, and extracorporeal life support devices. Repairing the cardiac lesion or removing the device decreases the incidence of gastrointestinal bleeding by normalizing the acquired von Willebrand coagulopathy and decreasing the amount of gastrointestinal AVMs likely to bleed. We describe a case of a 67-year-old woman found to have Heyde's syndrome arising from a subvalvular aortic membrane resulting in severe subaortic stenosis with no other significant cardiac lesion. She underwent successful resection of the membrane with septal myectomy, relieving the severe subaortic stenosis and resolving her anemia. Years later, she re-presented with severe gastrointestinal bleeding from gastrointestinal malformations. Early recognition of these cardiac lesions with gastrointestinal bleeds may help decrease the morbidity and mortality that Heyde's syndrome portends and provide evidence for early intervention.

Reusable Fluorescent Nanobiosensor Integrated in a Multiwell Plate for Screening and Quantification of Antidiabetic Drugs.

A highly stable and reusable fluorescent multisample nanobiosensor for the detection of α-glucosidase inhibitors has been developed by coupling fluorescent liposomal nanoparticles based on conjugated polymers (L-CPNs) to the enzyme α-glucosidase, one of the main target enzymes in the treatment of type 2 diabetes. The mechanism of sensing is based on the fluorescence "turn-on" of L-CPNs by p-nitrophenol (PNP), the end product of the enzymatic hydrolysis of p-nitrophenyl-α-d-glucopyranoside. L-CPNs, composed of lipid vesicles coated with a blue-emitting cationic polyfluorene, were designed and characterized to obtain a good response to PNP. Two nanobiosensor configurations were developed in this study. In the first step, a single-sample nanobiosensor composed of L-CPNs and α-glucosidase entrapped in a sol-gel glass was developed in order to characterize and optimize the device. In the second part, the nanobiosensor was integrated and adapted to a multiwell microplate and the possibility of reusing it and performing multiple measurements simultaneously with samples containing different α-glucosidase inhibitors was investigated. Using super-resolution confocal microscopy, L-CPNs could be visualized within the sol-gel matrix, and the quenching of their fluorescence, induced by the substrate, was directly observed in situ. The device was also shown to be useful not only as a platform for screening of antidiabetic drugs but also for quantifying their presence. The latter application was successfully tested with the currently available drug, acarbose.

Layer-by-layer polymer coating of carbon nanotubes: tuning of electrical conductivity in random networks.

In this work we show that the electrical conductivity and thermoelectric power of random networks of carbon nanotube (CNT) films can be tuned by means of a layer-by-layer polymer coating technique of the individual nanotubes. Using this approach, nanotubes dispersed in water are coated before the formation of the film, achieving a control of the transport properties independent of the substrate. Below a certain temperature the conductivity departs from the ohmic behavior and enters a tunneling regime with an energy barrier for electron transport determined by the width of the polymer layer. The excellent control over the conductivity and the possibility of using the polymer coating as a gate dielectric material could be an important step for the development of an easy and scalable approach for the fabrication of CNT-based thin film transistors.

Formation of complexes between the conjugated polyelectrolyte poly{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} bromide (HTMA-PFP) and human serum albumin.

The interaction between the conjugated polyelectrolyte poly{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} bromide (HTMA-PFP) and human serum albumin (HSA) has been investigated from changes observed in both the spectroscopic properties of HTMA-PFP and the intrinsic fluorescence of HSA. Absorption and fluorescence spectra of HTMA-PFP suggest that HTMA-PFP and HSA form polymer-protein complexes due to electrostatic interactions between the cationic side chains of HTMA-PFP and the negatively charged surface of the protein. Interaction between both macromolecules induces an increase in the fluorescence signal of HTMA-PFP, which suggests that hydrophobic forces also contribute to the polymer-protein complex stabilization. In addition, this interaction causes a decrease in the HSA fluorescence, partially due to static quenching and energy transfer between both macromolecules. Effects of HTMA-PFP on the thermal stability and protein conformation were explored from CD experiments. Results indicate that as polymer is added it binds to HSA and initiates unfolding. This unfolding process induces HTMA-PFP chains to become more extended, disrupting backbone interactions and increasing polymer fluorescence intensity.

The Interaction of Temozolomide with Blood Components Suggests the Potential Use of Human Serum Albumin as a Biomimetic Carrier for the Drug.

The interaction of temozolomide (TMZ) (the main chemotherapeutic agent for brain tumors) with blood components has not been studied at the molecular level to date, even though such information is essential in the design of dosage forms for optimal therapy. This work explores the binding of TMZ to human serum albumin (HSA) and alpha-1-acid glycoprotein (AGP), as well as to blood cell-mimicking membrane systems. Absorption and fluorescence experiments with model membranes indicate that TMZ does not penetrate into the lipid bilayer, but binds to the membrane surface with very low affinity. Fluorescence experiments performed with the plasma proteins suggest that in human plasma, most of the bound TMZ is attached to HSA rather than to AGP. This interaction is moderate and likely mediated by hydrogen-bonding and hydrophobic forces, which increase the hydrolytic stability of the drug. These experiments are supported by docking and molecular dynamics simulations, which reveal that TMZ is mainly inserted in the subdomain IIA of HSA, establishing π-stacking interactions with the tryptophan residue. Considering the overexpression of albumin receptors in tumor cells, our results propose that part of the administered TMZ may reach its target bound to plasma albumin and suggest that HSA-based nanocarriers are suitable candidates for designing biomimetic delivery systems that selectively transport TMZ to tumor cells.

CT-Based Hepatic Residual Volume and Predictors of Outcomes of Patients with Hepatocellular Carcinoma Unsuitable for Surgical Therapy Undergoing Transarterial Chemoembolization.

RATIONALE AND OBJECTIVES: To assess the association between baseline CT-based volumetric parameters and biochemical hepatic evaluations, such as, Child-Pugh, MELD score, and modified MELD-Na score, on the prediction of outcomes of patients with HCC undergoing transarterial chemoembolization (TACE). MATERIALS AND METHODS: A retrospective of a prospectively maintained database, single arm, and single center study was performed including 41 patients with diagnosis of hepatocellular carcinoma treated with TACE. Study endpoints included liver dysfunction (new events of ascites, encephalopathy, and/or death) and overall survival rate. Multi-phase CT-based volumetric analysis was performed to calculate total liver volume and tumor volume using portal and late arterial phases, respectively. Residual volume was calculated subtracting the tumor volume minus the total liver volume. Child-Pugh, MELD score, and MELD-Na score were measured during the baseline evaluation. RESULTS: At a median follow-up time of 8 months (IQR, 5-14), 16 patients (39%) were diagnosed with hepatic dysfunction. In patients with hepatic dysfunction, the median residual hepatic volume was 1002.1 cc (IQR, 633-1077.1 cc) compared to patients with normal liver function post-TACE with a median residual volume of 1233 cc (IQR, 1018.7-1437.6 cc) (p = 0.02). Survival analysis demonstrated an overall survival rate of 95%, 90%, 85% at 30 days, 12 months, and 24 months, respectively. The overall survival rate in patients with Child-Pugh A was 100%, 97%, and 97% at 6, 12, and 24 months, respectively; compared to patients with Child Pugh B with an overall survival of rate of 86%, 78%, and 78% at 6, 12, and 24 months, respectively (p = 0.07). Median baseline MELD-Na score was higher in patients that died during the study period compared to patients that survived (6.7 [IQR, 5-14.2] versus 4.1 [IQR, 2.14-6.85]) (p = 0.09). CONCLUSION: Low baseline CT-based residual volume is associated with the occurrence of hepatic dysfunction at a median time of 8 months. Baseline Child-Pugh A patients were found to have higher survival rate than Child-Pugh B. Interestingly, higher baseline MELD-Na score was associated with mortality.

Biophysical and functional characterization of an ion channel peptide confined in a sol-gel matrix.

Immobilization of zwitterionic lipid membranes in sol-gel matrices induces irreversible alterations of the bilayer fluidity, which can limit the use of these systems for practical applications. Recently, we have reported that electrostatic interactions between phospholipids polar heads and the negative-charged silica surface of the porous matrix should be the cause of such behavior. In the present work, we analyze the effect of these interactions on the biophysical and functional properties of the ion-channel peptide gramicidin, entrapped in a sol-gel matrix, to get more insight on the ability of these inorganic materials to immobilize ion channels and other membrane-bound proteins. Gramicidin was reconstituted in anionic and zwitterionic liposomes and the effects of sol-gel immobilization on the biophysical properties of gramicidin were determined from changes in the photophysical properties of its tryptophan residues. In addition, the physical state of the immobilized lipid membrane containing gramicidin was analyzed by measuring the spectral shift of the fluorescent probe Laurdan. Finally, the ion-channel activity of the peptide was monitored upon sol-gel immobilization through a fluorescence quenching assay using the fluorescent dye pyrene-1,3,6,8-tetrasulfonic acid (PTSA). Results show that the channel properties of the immobilized gramicidin are preserved in both zwitterionic and anionic liposomes, even though the zwitterionic polar heads interact with the porous surface of the host matrix.