Abstract  AIM: This study examined the effects of prenatal alcohol exposure on childhood development trajectories in a rural South African community between 2003 and 2008.

METHODS: We assessed 121 children at 7-12 months (year one) and 5-6 years (year five) using the Griffiths Mental Developmental Scales - Extended Revised, which measures sensorimotor, cognitive and social development, with lower scores indicating developmental delay. We also interviewed their mothers or caregivers. Three groups were identified: 29 with foetal alcohol syndrome (FAS) or partial FAS (pFAS), 57 more who had been exposed to alcohol and 35 controls who had not.

RESULTS: The scale's total score was higher in the controls than in the FAS/pFAS group at year one and year five and in the alcohol-exposed group at year five. Many groups' trajectories declined when compared with global norms, but the trajectories in the FAS/pFAS and the alcohol-exposed groups declined more than the controls for eye-hand and performance and total score. Earlier pregnancy recognition in the FAS/pFAS group correlated strongly (r = -0.77) with higher GQ in year five.

CONCLUSION: FAS/pFAS and prenatal alcohol exposure affected the Griffiths scores more than the control group. Efforts are needed to detect pregnancy early and reduce alcohol exposure.

Abstract  Virtually all biomaterials are susceptible to biofilm formation and, as a consequence, device-associated infection. The concept of an immobilized liquid surface, termed slippery liquid-infused porous surfaces (SLIPS), represents a new framework for creating a stable, dynamic, omniphobic surface that displays ultralow adhesion and limits bacterial biofilm formation. A widely used biomaterial in clinical care, expanded polytetrafluoroethylene (ePTFE), infused with various perfluorocarbon liquids generated SLIPS surfaces that exhibited a 99% reduction in S. aureus adhesion with preservation of macrophage viability, phagocytosis, and bactericidal function. Notably, SLIPS modification of ePTFE prevents device infection after S. aureus challenge in vivo, while eliciting a significantly attenuated innate immune response. SLIPS-modified implants also decrease macrophage inflammatory cytokine expression in vitro, which likely contributed to the presence of a thinner fibrous capsule in the absence of bacterial challenge. SLIPS is an easily implementable technology that provides a promising approach to substantially reduce the risk of device infection and associated patient morbidity, as well as health care costs.

Abstract  BACKGROUND: Tumour hypoxia limits the effectiveness of radiation therapy. Delivering normobaric or hyperbaric oxygen therapy elevates pO2 in both tumour and normal brain tissue. However, pO2 levels return to baseline within 15 minutes of stopping therapy.

AIM: To investigate the effect of perfluorocarbon (PFC) emulsions on hypoxia in subcutaneous and intracranial mouse gliomas and their radiosensitising effect in orthotopic gliomas in mice breathing carbogen (95%O2 and 5%CO2).

RESULTS: PFC emulsions completely abrogated hypoxia in both subcutaneous and intracranial GL261 models and conferred a significant survival advantage orthotopically (Mantel Cox: p = 0.048) in carbogen breathing mice injected intravenously (IV) with PFC emulsions before radiation versus mice receiving radiation alone. Carbogen alone decreased hypoxia levels substantially and conferred a smaller but not statistically significant survival advantage over and above radiation alone.

CONCLUSION: IV injections of PFC emulsions followed by 1h carbogen breathing, radiosensitises GL261 intracranial tumors.

Abstract  Biological and thermodynamic properties of a new homologous series of highly fluorinated bispyridinium cationic gemini surfactants, differing in the length of the spacer bridging the pyridinium polar heads in 1,1' position, are reported for the first time. Interestingly, gene delivery ability is closely associated with the spacer length due to a structural change of the molecule in solution. This conformation change is allowed when the spacer reaches the right length, and it is suggested by the trends of the apparent and partial molar enthalpies vs molality. To assess the compounds' biological activity, they were tested with an agarose gel electrophoresis mobility shift assay (EMSA), MTT proliferation assay and Transient Transfection assays on a human rhabdomyosarcoma cell line. Data from atomic force microscopy (AFM) allow for morphological characterization of DNA nanoparticles. Dilution enthalpies, measured at 298K, enabled the determination of apparent and partial molar enthalpies vs molality. All tested compounds (except that with the longest spacer), at different levels, can deliver the plasmid when co-formulated with 1,2-dioleyl-sn-glycero-3-phosphoethanolamine (DOPE). The compound with a spacer formed by eight carbon atoms gives rise to a gene delivery ability that is comparable to that of the commercial reagent. The compound with the longest spacer compacts DNA in loosely condensed structures by forming bows, which are not suitable for transfection. Regarding the compounds' hydrogenated counterparts, the tight relationship between the solution thermodynamics data and their biological performance is amazing, making "old" methods the foundation to deeply understanding "new" applications.

Abstract  The transfection performance of polycations is often hampered by various systemic barriers that pose conflicting requirements for material design. Herein, we developed fluorinated, ROS-cleavable polyethylenimine (PEI) for effective and serum-resistant gene delivery to cancer cells, by harmonizing the inconsistency between DNA condensation and release, and the inconsistency between cellular internalization and serum stability. Low-molecular weight (MW) PEI was cross-linked with a diselenide-containing linker and further modified with fluorocarbon chains. The obtained high-MW DSe-PEI-F has potent DNA condensation as well as intracellular DNA delivery capabilities, while in the cytoplasm of cancer cells, it can rapidly degrade into low-MW segments upon ROS treatment to promote DNA release and reduce the material toxicity. As such, DSe-PEI-F showed high transfection efficiencies in cancer cells in the presence of serum, outperforming the commercial reagent PEI 25k by several orders of magnitude. This study thus provides an effective approach to overcome various barriers against non-viral gene delivery, which contributes to the development of a new class of gene vectors with high efficiency and low toxicity.

Abstract  A novel series of tubulin polymerization inhibitors, based on fluorinated derivatives of isocombretastatin A-4 was synthesized with the goal of evaluating the effect of these compounds on the proliferative activity. The introduction of fluorine atom was performed on the phenyl ring or at the linker between the two aromatic rings. The modification of isoCA-4 by introduction of difluoromethoxy group at the para-position (3i) and substitution of the two protons of the linker by two fluorine atoms (3m), produced the most active compounds in the series, with IC50values of 0.15-2.2 nM (3i) and 0.1-2 nM (3m) respectively, against a panel of six cancer cell lines. Compounds 3i and 3m had greater antiproliferative activity in comparison with references CA-4 or isoCA-4, the presence of fluorine group leads to a significant enhancement of the antiproliferative activity. Molecular docking studies indicated that compounds 3i and 3m occupy the colchicine binding site of tubulin. Evaluation of cytotoxicity in Human noncancer cells indicated that the compounds 3i and 3m were practically ineffective in quiescent peripheral blood lymphocytes, and may have a selective antiproliferative activity against cancer cells. Analyses of cell cycle distribution, and morphological microtubules organization showed that compound 3m induced G2/M phase arrest and, dramatically disrupted the microtubule network.

Abstract  Kinetic sorption of bisphenol A (BPA), carbamazepine (CMZ) and ciprofloxacin (CIP) by three palygorskite-montmorillonite (Pal-Mt) granule sizes was studied. For BPA, CMZ and CIP, apparent sorption equilibrium was reached within about 3, 5 and 16 h, respectively. The highest and the lowest sorption capacities were by the small and the large granule sizes, respectively. Experimental results were compared to various sorption kinetics models to gain insights regarding the sorption processes and achieve a predictive capacity. The pseudo-second order (PSO) and the Elovich models performed the best while the pseudo-first order (PFO) model was only adequate for CMZ. The intraparticle-diffusion (IPD) model showed a two-step linear plot of BPA, CMZ and CIP sorption versus square root of time that was indicative of surface-sorption followed by IPD as a rate-limiting process before equilibrium was reached. Using the pseudo-first order (PFO) and the pseudo-second order (PSO) rate constants combined with previously-established Langmuir equilibrium sorption models, the kinetic sorption (ka) and desorption (kd) Langmuir kinetic rate constants were theoretically calculated for BPA and CIP. Kinetic sorption was then simulated using these theoretically calculated kaand kdvalues, and the simulations were compared to the observed behavior. The simulations fit the observed sorbed concentrations better during the early part of the experiments; the observed sorption during later times occurred more slowly than expected, supporting the hypothesis that IPD becomes a rate-limiting process during the course of the experiment.

Abstract  The ghrelin receptor (GhrR) is a widely investigated target in several diseases. However, the current knowledge of its role and distribution in the brain is limited. Recently, the small and non-peptidic compound (S)-6-(4-bromo-2-fluorophenoxy)-3-((1-isopropylpiperidin-3-yl)methyl)-2-methylpyrido[3,2-d]pyrimidin-4(3H)-one ((S)-9) has been described as a GhrR ligand with high binding affinity. Here, we describe the synthesis of fluorinated derivatives, the in vitro evaluation of their potency as partial agonists and selectivity at GhrRs, and their physicochemical properties. These results identified compounds (S)-9, (R)-9, and (S)-16as suitable parent molecules for18F-labeled positron emission tomography (PET) radiotracers to enable future investigation of GhrR in the brain.

Abstract  Prenatal alcohol exposure has been linked to a broad range of developmental deficits, with eyeblink classical conditioning (EBC) among the most sensitive endpoints. This fMRI study compared EBC-related brain activity in 47 children with fetal alcohol syndrome (FAS), partial FAS (PFAS), heavily exposed (HE) non-syndromal children, and healthy controls. All of the children had previously participated in two EBC studies conducted as part of our longitudinal study of fetal alcohol spectrum disorders. Although learning-related behavioral differences were seen in all groups during the scans, controls showed more conditioned responses (CR) than the alcohol-exposed groups. Despite lower conditioning levels relative to controls, the exposed groups exhibited extensive cerebellar activations. Specifically, children with FAS/PFAS showed increased activation of cerebellar lobule VI in session 2, while HE children showed increased activation in session 1. Continuous measures of prenatal alcohol use correlated with learning-related activations in cerebellum and frontal cortices. Only controls showed significant cerebellar activation-CR correlations in the deep nuclei and lateral lobule VI, suggesting that these key regions supporting EBC may be functionally disorganized in alcohol-exposed children. These findings are the first to characterize abnormalities in brain function associated with the behavioral conditioning deficits seen in children with prenatal alcohol exposure.

Abstract  The ε-Keggin ion AlO4Al12(OH)24(H2O)127+(ε-K Al137+) is a double-edged sword, because it commonly acts as a toxic component toward aquatic organisms, but also is considered to be an effective coagulant. Gaining deep insight into the transformation of ε-K Al137+in the presence of coexisting ligands would have significant implications for water environmental science, as well as for practical water purification. The aggregation and dissociation of aqueous Al137+induced by fluoride (F-) substitution were herein investigated using nuclear magnetic resonance, electrospray ionization-mass spectrometry, and theoretical calculations. The F-substitution on η-OH2sites was extremely fast, reducing the charge of ε-K Al137+so that the repulsive force between fluorinated Al13species was immediately reduced. Consequently, fluorinated Al13aggregated, with the formula [Al13F5]2+, which was demonstrated by calculating the Gibbs free energy changes (ΔrG) of the substitution reactions involved. Moreover, the replacement of η-OH2with F-weakened the strength of Al-OHa/bbonds and thus prompted the replacement of μ-OHa/bwith F-. In addition, fluorination prompted [Al13F5]2+to dissociate to oligomers.

Abstract  Liver X receptors (LXRs) have anti-inflammatory properties. Whether LXRs play a role in post-transcriptional control of inflammatory cytokine expression is not clear. Here, we firstly identified that the synthetic LXR agonist T0901317 promoted IL-1β, IL-6 and TNFα mRNA degradation. Moreover, T0901317 destabilized TNFα mRNA through its 3'-untranslated region. In addition, T0901317 increased the expression of tristetraprolin (TTP), while antagonizing TTP with siRNA abrogated T0901317-mediated inflammatory cytokine mRNA decay. Interestingly, T0901317 repressed LPS-induced phosphorylation of ERK1/2 and p38 mitogen-activated protein kinase (MAPK) in THP-1 macrophages. The evidence presented here confirms that LXR activation with T0901317 inhibits the phosphorylation of ERK1/2 and p38 MAPK, likely resulting in the increased expression of TTP and the decay of LPS-induce inflammatory cytokine mRNAs.

Abstract  High photovoltage dye-sensitized solar cells (DSCs) offer an exceptional opportunity to power electrocatalysts for the production of hydrogen from water and the reduction of CO2to usable fuels with a relatively cost-effective, low-toxicity solar cell. Competitive recombination pathways such as electron transfer from TiO2films to the redox shuttle or oxidized dye must be minimized to achieve the maximum possible photovoltage (Voc) from DSC devices. A high Vocof 882 mV was achieved with the iodide/triiodide redox shuttle and a ruthenium NCS-ligated dye, HD-2-mono, by utilizing a combined approach of (1) modulating the TiO2surface area through film thickness and nanoparticle size selection, (2) addition of a MgO insulating layer, and (3) capping available TiO2film surface sites post film sensitization with an F-SAM (fluorinated self-assembled monolayer) treatment. The exceptional Vocof 882 mV observed is the highest achieved for the popular NCS containing ruthenium sensitizers with >5% PCE and compares favorably to the 769 mV value observed under common device preparation conditions.

Abstract  The iodothyronine deiodinases are selenoenzymes that regulate the activity of thyroid hormone via specific inner- or outer-ring deiodination. In humans, type 1 deiodinase (D1) is highly expressed in the liver, but the mechanism by which its gene expression is regulated remains to be elucidated. Liver X receptor α (LXRα), a transcription factor of the nuclear receptor superfamily, is highly expressed in the liver, where it functions as a sensor for excess intracellular oxysterols. LXRα interacts with other nuclear receptors on promoters of genes that contain a binding core sequence for nuclear receptors. In addition, it is reported that the promoter of the gene encoding human D1 (hDIO1) contains the core sequence for one of nuclear receptors, thyroid hormone receptor (TR). We investigated the involvement of LXRα in the regulation of hDIO1, in the liver. We performed hDIO1 promoter-reporter assays using a synthetic LXR agonist, T0901317, and compared promoter activity between a human liver carcinoma cell line, HepG2, and a clone of human embryonic kidney cells, TSA201. We defined the region between nucleotides -131 and -114, especially nucleotides -126 and -125, of the hDIO1 promoter as critical for basal and LXRα-mediated specific transcriptional activation in HepG2 cells. An increase in hDIO1 expression was observed in LXRα-stimulated cells, but absent in cycloheximide-treated cells, indicating that new protein synthesis is required for LXRα-mediated regulation of hDIO1. On the other hand, electrophoretic mobility shift assays revealed that LXRα and RXRα bound to the hDIO1 promoter. We also demonstrated that LXRα and TRβ compete with each other on this specific region of the promoter. In conclusion, our results indicated that LXRα plays a specific and important role in activation of TH by regulating D1, and that LXRα binds to and regulates the hDIO1 promoter, competing with TRβ on specific sequences within the promoter.

Abstract  Two challenges to grow KBe2BO3F2(KBBF), the best known deep-ultraviolet nonlinear optical (NLO) material to date, are the limited crystal sizes and the use of a highly toxic element (Be). Herein we report on the discovery of a novel anhydrous non-centrosymmetric alkali fluorinated borophosphate KB(PO4)F (KBPF) featuring a cut-off wavelength of less than 200 nm and a large second-harmonic generation (SHG) effect similar to KH2PO4(KDP), hence representing a new promising deep-ultraviolet NLO material. The KBPF crystals consisting of common elements can be grown using green and cost effective processes and do not show any detectable hygroscopicity. The title compound also features a 2-dimensional layer [BPO4F]∞built from [BO3F]4-and [PO4]3-tetrahedral groups but has much stronger interlayer bonds than KBBF, allowing the growth of large crystals. The title compound has been characterized by PXRD, SEM, TG-DSC, FTIR, UV-Vis-NIR diffuse reflectance and SHG analyses as well as single-crystal X-ray structure refinements. The optical properties of KBPF have also been evaluated by first-principles calculations at the density functional theory (DFT) level.

Abstract  Due to the high cost of domoic acid (DA), different carboxylic acid compounds including indole-3-acetic acid (IAA), pyrrole-2-formic acid (PFA), pyridine-2,3-dicarboxylic anhydride (PDA), trimesitinic acid (TA) and citric acid (CA) were investigated as dummy templates for the molecularly imprinted solid-phase extraction (MISPE) for selective isolation and pre-concentration of an amnesic shellfish poison (ASP), DA. The highest binding amount of the polymers towards DA was obtained when CA was used as dummy template owing to its high hydrophilicity. In addition, the "four-point" recognition site constructed by three COOH groups and a OH group in CA was also speculated to be the reason for the high binding amount of CA-MIPs and the rebinding of DA can be depend on the three COOH groups and a NH group with conformational change in the recognition process. Finally, the CA-MISPE column was chosen for DA isolation and pre-concentration and effective result was obtained with recoveries higher than 90% and relative standard deviation (RSD) less than 5% (n=3). This new polymer can be effectively applied to the monitoring and predicting the existence of trace DA.

Abstract  BODIPYs (boron dipyrromethenes) are fluorescent dyes which show high stability and quantum yields. They feature the possibility of selective18F-fluorination at the boron-core. Attached to a bioactive molecule and labeled with [18F]fluorine, the resulting compounds are promising tracers for multimodal imaging in vivo and can be used for PET and fluorescence imaging. A BODIPY containing a phenyl and a hydroxy substituent on boron was synthesized and characterized. Fluorinated and hydroxy substituted dyes were coupled to an isatin-based caspase inhibitor via cycloaddition and the resulting compounds were evaluated in vitro in caspase inhibition assays. The metabolic stability and the formed metabolites were investigated by incubation with mouse liver microsomes and LC-MS analysis. Subsequently the fluorophores were labeled with [18F]fluorine and an in vivo biodistribution study using dynamic PET was performed.

Abstract  Here, 3 fluorinated intermediates of drug were synthesized: (M1), (M2), (M3). Three new anticoagulant rodenticides were designed which were based on 4-hydroxycoumarin or 1,3-indandione, added acute toxicity groups containing fluorine. The structures of synthesized compounds were analyzed and proved by FT-IR spectroscopy and1H nuclear magnetic resonance (1H-NMR). The compounds were also evaluated for their anticoagulant and acute biologic activity. In addition, both the acute orally toxicity and the feeding indexes of R1and R2were tested. The result of the experiment proved that the new synthesis of 1, 3 - indan diketone for maternal new anticoagulant rodenticide can replace the current 4 - hydroxyl coumarin as the mother of the second generation anticoagulant rodenticide and 1, 3 - indan diketone for maternal new anticoagulant rodenticides will have a good development prospect.

Abstract  In October 2007, the Food and Drug Administration mandated significant revisions to product labeling for the commercially available echocardiographic contrast agents (ECA) Definity and Optison after spontaneous healthcare provider reports of 4 patient deaths and ≈190 severe cardiopulmonary reactions occurring in close temporal relationship to ECA administration. Since then, multiple large ECA safety studies have been published and have included outpatients, hospitalized patients (including the critically ill), patients undergoing stress echocardiography, and patients with pulmonary hypertension. In addition, the Food and Drug Administration has convened 2 Advisory Committee meetings and the product labels for Optison and Definity have been substantially revised with a softening of safety restrictions. In this review, we will address the safety of ECA use in patients with serious cardiopulmonary conditions, patients with intracardiac shunts, and special patient populations including pulmonary hypertension, pediatrics, and pregnancy. In addition, we will discuss the confounding role of pseudocomplication in attribution of adverse events during diagnostic testing, the current status of the ECA Black Box Warning, and recommended safety precautions during ECA administration.

Abstract  Context: Elagolix is a nonpeptide, oral gonadotropin-releasing hormone (GnRH) antagonist being developed for sex-hormone-dependent diseases in women.

Objective: We evaluated the pharmacokinetics and pharmacodynamics of elagolix.

Design, Setting, and Participants: This study was a randomized, double-blind, placebo-controlled, multiple-ascending dose study in 45 healthy premenopausal women at a research unit.

Interventions: Elagolix [150 mg once daily or 100, 200, 300, or 400 mg twice daily (BID)] or placebo was administered for 21 days.

Main Outcome Measures: Main outcome measures were elagolix pharmacokinetics, suppression of gonadotropics [follicle-stimulating hormone (FSH), luteinizing hormone (LH)] and ovarian hormones [estradiol (E2), progesterone (P)], and adverse events.

Results: Elagolix was rapidly absorbed after oral dosing, reaching maximum concentrations at 1.0 to 1.5 hours, with a half-life of 4 to 6 hours. FSH, LH, and E2 were suppressed within hours of elagolix administration on day 1. Dose-dependent suppression of E2 was observed, with maximum suppression achieved with elagolix 200 mg BID. Dose-dependent suppression of FSH and LH was also observed, with maximal or near-maximal suppression achieved at 300 mg BID and 200 mg BID, respectively. At elagolix doses ≥100 mg BID, P concentrations remained at anovulatory levels throughout 21 days of dosing. The most frequently reported adverse events were headache and hot flush.

Conclusions: Elagolix administration allows for modulation of gonadotropin and ovarian hormone concentrations, from partial suppression at lower doses to nearly full suppression at higher doses. The results of this study provide a rationale for elagolix dose selection for treatment of sex hormone-dependent diseases in women.

Abstract  Capecitabine is an oral fluoropyrimidine chemotherapeutic agent, which, after oral administration, is metabolized to its active cytotoxic compound: 5-fluorouracil (5-FU). Cardiotoxicity is a recognized side effect of 5-FU, a closely related fluorinated pyrimidine antagonist. In the present report, we report on two patients who were admitted to our department after being treated with oral capecitabine for colorectal carcinoma and developed symptoms and signs of acute myocardial infarction that resolved after appropriate treatment and monitoring. The above two cases are discussed in the context of fluoropyrimidine, 5-FU, and capecitabine-induced cardiotoxicity; in addition, a detailed literature review of relevant cases and patient series reports is presented.

Abstract  Bimetallic particles based on gold and iron have been gathering increasing interest in biomedical applications because of the synergic combination of the plasmonic features of the inert gold component with the magnetic properties of the iron or iron oxide fraction, that makes these hybrid nanomaterials suitable for imaging, therapeutic and analytical applications. In this minireview, we emphasize gold-based nanomaterials with potential for Magnetic Resonance Imaging, focusing on Au-Fe hybrid systems as potential T2-weighted, goldbased contrast agents.

Abstract  The liver X receptors (LXRs) is an important component of the nuclear receptor (NR) superfamily. Previous studies have shown that the LXRs possessed antitumor activity in various types of tumor cells. However, the complicated mechanisms underlying the antitumor activity remain largely unexplored. In this study, we incubated A549 cells with the compound T0901317, a specific LXRs agonist, for 24 h. The MTT assay was used to assess cell viability. Transwell assays were used to evaluate cell migration and invasion. The shRNA was utilized for RNA interference. The target gene and protein expression levels were assessed using reverse transcription-PCR and western blot assay. The DNA-binding activity of nuclear factor κB (NF-κB) was examined using electrophoretic mobility shift assays. Luciferase reporter assay was used to detect the binding of NF-κB to the matrix metalloproteinase-9 (MMP-9) promoter. We found that T0901317 inhibited the invasion and migration of A549 cells in a dose-dependent manner. Meanwhile, we further indicated that activation of LXRβ, one subtype of LXRs, can downregulate MMP-9 expression. More importantly, activation of LXRβ triggered by T0901317 inhibited the invasion and metastasis of A549 cells by repressing NF-κB/MMP-9 signaling pathway. Taken together, our study shows that activation of LXRs triggered by T0901317 inhibits the invasion and metastasis of human non-small-cell lung cancer by repressing the NF-κB/MMP-9 signaling pathway.

Abstract  Due to their small size, nanoparticles possess unique properties. Cerium oxide nanoparticles have been already studied for their capacity to adsorb and neutralize toxic compounds including organophosphates. By covalently grafting these nanoparticles to a thickening polymer, their potential aggregation resulting in a loss of surface area and their potential toxicity are avoided. Indeed, copolymers easily form gels in water at neutral pH thanks to low interactions occurring between polymeric chains; thus, gels can be spread on membrane supports to afford protective barriers. However, as we demonstrated previously, a formulation step of these hydride nanoparticle-polymeric compounds is necessary to overcome the cracking of the coating during drying. This work reports the impact of many factors on the efficiency of a new active Topical Skin Protectant (aTSP) including: (1) the presence of CeO2nanoparticles in the protective coating and their amount, (2) their grafting to a perfluorocarbon thickening polymer and (3) the formulation of the CeO2nanoparticle-grafted polymer. The combination of all the benefit parameters led to a very effective new aTSP against paraoxon penetration. The major in vitro diffusion studies were performed in Franz-type diffusion cells on two artificial membranes (silicone and Strat-M) and final validation on ex vivo human skin. The comparison of 24 h-exposure between membrane results indicated a difference in the behavior between the two artificial supports and the biological model; Strat-M membranes seeming closer to human skin results. Therefore, positive results regarding occlusive conditions should be confirmed with human skin.

Abstract  Gene-directed enzyme-prodrug therapy (GDEPT) is a promising anti-cancer strategy. However, inadequate prodrugs, inefficient prodrug activation, and a lack of non-invasive imaging capabilities have hindered clinical progression. To address these issues, we used a high-throughput Escherichia coli platform to evolve the multifunctional nitroreductase E. coli NfsA for improved activation of a promising next-generation prodrug, PR-104A, as well as clinically relevant nitro-masked positron emission tomography-imaging probes EF5 and HX4, thereby addressing a critical and unmet need for non-invasive bioimaging in nitroreductase GDEPT. The evolved variant performed better in E. coli than in human cells, suggesting optimal usefulness in bacterial rather than viral GDEPT vectors, and highlighting the influence of intracellular environs on enzyme function and the shaping of promiscuous enzyme activities within the "black box" of in vivo evolution. We provide evidence that the dominant contribution to improved PR-104A activity was enhanced affinity for the prodrug over-competing intracellular substrates.