NAPS Fusion: A framework to overcome experimental data limitations to predict human performance and cognitive task outcomes.

In the area of human performance and cognitive research, machine learning (ML) problems become increasingly complex due to limitations in the experimental design, resulting in the development of poor predictive models. More specifically, experimental study designs produce very few data instances, have large class imbalances and conflicting ground truth labels, and generate wide data sets due to the diverse amount of sensors. From an ML perspective these problems are further exacerbated in anomaly detection cases where class imbalances occur and there are almost always more features than samples. Typically, dimensionality reduction methods (e.g., PCA, autoencoders) are utilized to handle these issues from wide data sets. However, these dimensionality reduction methods do not always map to a lower dimensional space appropriately, and they capture noise or irrelevant information. In addition, when new sensor modalities are incorporated, the entire ML paradigm has to be remodeled because of new dependencies introduced by the new information. Remodeling these ML paradigms is time-consuming and costly due to lack of modularity in the paradigm design, which is not ideal. Furthermore, human performance research experiments, at times, creates ambiguous class labels because the ground truth data cannot be agreed upon by subject-matter experts annotations, making ML paradigm nearly impossible to model. This work pulls insights from Dempster-Shafer theory (DST), stacking of ML models, and bagging to address uncertainty and ignorance for multi-classification ML problems caused by ambiguous ground truth, low samples, subject-to-subject variability, class imbalances, and wide data sets. Based on these insights, we propose a probabilistic model fusion approach, Naive Adaptive Probabilistic Sensor (NAPS), which combines ML paradigms built around bagging algorithms to overcome these experimental data concerns while maintaining a modular design for future sensor (new feature integration) and conflicting ground truth data. We demonstrate significant overall performance improvements using NAPS (an accuracy of 95.29%) in detecting human task errors (a four class problem) caused by impaired cognitive states and a negligible drop in performance with the case of ambiguous ground truth labels (an accuracy of 93.93%), when compared to other methodologies (an accuracy of 64.91%). This work potentially sets the foundation for other human-centric modeling systems that rely on human state prediction modeling.

Antiprion Activity of DB772 and Related Monothiophene- and Furan-Based Analogs in a Persistently Infected Ovine Microglia Culture System.

The transmissible spongiform encephalopathies are fatal neurodegenerative disorders characterized by the misfolding of the native cellular prion protein (PrP(C)) into the accumulating, disease-associated isoform (PrP(Sc)). Despite extensive research into the inhibition of prion accumulation, no effective treatment exists. Previously, we demonstrated the inhibitory activity of DB772, a monocationic phenyl-furan-benzimidazole, against PrP(Sc) accumulation in sheep microglial cells. In an effort to determine the effect of structural substitutions on the antiprion activity of DB772, we employed an in vitro strategy to survey a library of structurally related, monothiophene- and furan-based compounds for improved inhibitory activity. Eighty-nine compounds were screened at 1 µM for effects on cell viability and prion accumulation in a persistently infected ovine microglia culture system. Eleven compounds with activity equivalent to or higher than that of DB772 were identified as preliminary hit compounds. For the preliminary hits, cytotoxicities and antiprion activities were compared to calculate the tissue culture selectivity index. A structure-activity relationship (SAR) analysis was performed to determine molecular components contributing to antiprion activity. To investigate potential mechanisms of inhibition, effects on PrP(C) and PrP(Sc) were examined. While inhibition of total PrP(C) was not observed, the results suggest that a potential target for inhibition at biologically relevant concentrations is through PrP(C) misfolding to PrP(Sc) Further, SAR analysis suggests that two structural elements were associated with micromolar antiprion activity. Taken together, the described data provide a foundation for deeper investigation into untested DB compounds and in the design of effective therapeutics.

Structure-dependent inhibition of the ETS-family transcription factor PU.1 by novel heterocyclic diamidines.

ETS transcription factors mediate a wide array of cellular functions and are attractive targets for pharmacological control of gene regulation. We report the inhibition of the ETS-family member PU.1 with a panel of novel heterocyclic diamidines. These diamidines are derivatives of furamidine (DB75) in which the central furan has been replaced with selenophene and/or one or both of the bridging phenyl has been replaced with benzimidazole. Like all ETS proteins, PU.1 binds sequence specifically to 10-bp sites by inserting a recognition helix into the major groove of a 5'-GGAA-3' consensus, accompanied by contacts with the flanking minor groove. We showed that diamidines target the minor groove of AT-rich sequences on one or both sides of the consensus and disrupt PU.1 binding. Although all of the diamidines bind to one or both of the expected sequences within the binding site, considerable heterogeneity exists in terms of stoichiometry, site-site interactions and induced DNA conformation. We also showed that these compounds accumulate in live cell nuclei and inhibit PU.1-dependent gene transactivation. This study demonstrates that heterocyclic diamidines are capable of inhibiting PU.1 by targeting the flanking sequences and supports future efforts to develop agents for inhibiting specific members of the ETS family.

Anti-signal recognition particle autoantibody ELISA validation and clinical associations.

OBJECTIVE: The aim of this study was to develop and validate a quantitative anti-signal recognition particle (SRP) autoantibody serum ELISA in patients with myositis and longitudinal association with myositis disease activity. METHODS: We developed a serum ELISA using recombinant purified full-length human SRP coated on ELISA plates and a secondary antibody that bound human IgG to detect anti-SRP binding. Protein immunoprecipitation was used as the gold standard for the presence of anti-SRP. Serum samples from three groups were analysed: SRP(+) myositis subjects by immunoprecipitation, SRP(-) myositis subjects by immunoprecipitation and non-myositis controls. The ELISA's sensitivity, specificity, positive predictive value and negative predictive value were evaluated. Percentage agreement and test-retest reliability were assessed. Serial samples from seven SRP immunoprecipitation-positive subjects were also tested, along with serum muscle enzymes and manual muscle testing. RESULTS: Using immunoprecipitation, we identified 26 SRP(+) myositis patients and 77 SRP(-) controls (including 38 patients with necrotizing myopathy). Non-myositis control patients included SLE (n = 4) and SSc (n = 7) patients. Anti-SRP positivity by ELISA showed strong agreement (97.1%) with immunoprecipitation (κ = 0.94). The sensitivity, specificity, positive predictive value, and negative predictive value of the anti-SRP ELISA were 88, 100, 100 and 96, respectively. The area under the curve was 0.94, and test-retest reliability was strong (r = 0.91, P < 0.001). Serial samples showed that anti-SRP levels paralleled changes in muscle enzymes and manual muscle testing. CONCLUSION: We developed a quantitative ELISA for detecting serum anti-SRP autoantibodies and validated the assay in myositis. Longitudinal assessment of SRP levels by ELISA may be a useful biomarker for disease activity.

Targeting the DNA-binding activity of the human ERG transcription factor using new heterocyclic dithiophene diamidines.

Direct modulation of gene expression by targeting oncogenic transcription factors is a new area of research for cancer treatment. ERG, an ETS-family transcription factor, is commonly over-expressed or translocated in leukaemia and prostate carcinoma. In this work, we selected the di-(thiophene-phenyl-amidine) compound DB1255 as an ERG/DNA binding inhibitor using a screening test of synthetic inhibitors of the ERG/DNA interaction followed by electrophoretic mobility shift assays (EMSA) validation. Spectrometry, footprint and biosensor-surface plasmon resonance analyses of the DB1255/DNA interaction evidenced sequence selectivity and groove binding as dimer. Additional EMSA evidenced the precise DNA-binding sequence required for optimal DB1255/DNA binding and thus for an efficient ERG/DNA complex inhibition. We further highlighted the structure activity relationships from comparison with derivatives. In cellulo luciferase assay confirmed this modulation both with the constructed optimal sequences and the Osteopontin promoter known to be regulated by ERG and which ERG-binding site was protected from DNaseI digestion on binding of DB1255. These data showed for the first time the ERG/DNA complex modulation, both in vitro and in cells, by a heterocyclic diamidine that specifically targets a portion of the ERG DNA recognition site.

Anti-transcription intermediary factor 1-gamma autoantibody ELISA development and validation.

OBJECTIVES: A quantitative anti-transcription intermediary factor 1-gamma (anti-TIF1-γ) ELISA may improve the detection of cancer-associated myositis (CAM). The aims of this study were the development and validation of a quantitative anti-TIF1-γ autoantibody ELISA in patients with myositis. METHODS: We developed an ELISA using recombinant purified full-length human TIF1-γ. Patient serum was incubated with TIF1-γ-coated ELISA plates, and secondary antibody that bound human IgG was used to detect anti-TIF1-γ binding. Protein immunoprecipitation (IP) was used as the gold standard for the presence of anti-TIF1-γ. Serum samples from myositis patients with positive and negative anti-TIF1-γ by IP, from non-myositis autoimmune patients (SSc, SLE and RA) and from healthy controls were analysed. The ELISA's sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were evaluated. Agreement between the ELISA and IP results was determined using chi-squared and kappa tests. Test-retest reliability of the ELISA was assessed. RESULTS: We identified 55 myositis patients with and 111 controls without anti-TIF1-γ by IP. Anti-TIF1-γ positivity by ELISA showed strong agreement (93.9%) with IP results (κ = 0.87). The sensitivity, specificity, PPV, NPV and overall accuracy of the anti-TIF1-γ ELISA were 91%, 96%, 93%, 95% and 94%, respectively. The area under the curve (AUC) of a receiver operating characteristic (ROC) curve was 0.938. Test-retest reliability was strong (Pearson r = 0.913, P < 0.001). CONCLUSION: We developed a quantitative ELISA for detecting serum anti-TIF1-γ autoantibodies and validated the assay in myositis and other connective tissue disease patients. The availability of a validated, quantitative ELISA should improve the detection of anti-TIF1-γ autoantibodies and may improve the detection of CAM.

Posterior Lateral Arthrodesis as a Treatment Option for Lumbar Spinal Stenosis: Safety and Early Clinical Outcomes.

Introduction: Lumbar spinal stenosis (LSS) is a common condition caused by degenerative changes in the lumbar spine with age. LSS is caused by a variety of factors, including degenerative spondylosis and spondylolisthesis. People suffering with LSS experience neurogenic claudication, which causes severe physical limitations, discomfort, and a decrease in quality of life. Less invasive procedures are now being researched to improve the prognosis, success rate, and safety of LSS treatments. Posterior lateral spinal arthrodesis (PLSA) is a new surgical treatment for LSS. This study looks at the procedural and patient safety of PLSA. Materials and methods: This study is a multicenter retrospective analysis of the safety of PLSA who met the clinical indications for PLSA and underwent the procedure at eight interventional spine practices. Data was collected on demographical information, pre-procedural numeric rating scale score (NRS), post-procedural NRS, and complication reporting. Patients who were included had LSS with or without spondylolisthesis and had failed conservative treatments. A descriptive statistical analysis was performed to report the outcomes. Results were reported as mean and standard deviations for continuous outcomes, and frequency (%) for categorical outcomes. Results: This retrospective analysis involved 191 patients and 202 PLSA implants. The majority of patients were male Caucasians with a mean age of 69.2 years and a BMI of 31.1. A large majority of implants were placed at the L4-5 level, and the average pre-procedural NRS was 6.3 while the average post-procedural NRS was 3.1, indicating a 50.8% reduction in pain (p < 0.0001). Two patients reported complications, but they were unrelated to the device or surgical procedure; no infections, device malfunctions, or migrations were reported in the patient cohort. Conclusion: Preliminary results with PLSA implants indicate that it is a safe treatment option for patients with moderate LSS who do not respond to conservative management.

In vitro and in vivo activities of dicationic diguanidino compounds against Echinococcus multilocularis metacestodes.

Alveolar echinococcosis (AE) is a disease predominantly affecting the liver, with metacestodes (larvae) of the tapeworm Echinococcus multilocularis proliferating and exhibiting tumor-like infiltrative growth. For many years, chemotherapeutical treatment against alveolar echinococcosis has relied on the benzimidazoles albendazole and mebendazole, which require long treatment durations and exhibit parasitostatic rather than parasiticidal efficacy. Although benzimidazoles have been and still are beneficial for the patients, there is clearly a demand for alternative and more efficient treatment options. Aromatic dications, more precisely a small panel of di-N-aryl-diguanidino compounds, were screened for efficacy against E. multilocularis metacestodes in vitro. Only those with a thiophene core group were active against metacestodes, while furans were not. The most active compound, DB1127, was further investigated in terms of in vivo efficacy in mice experimentally infected with E. multilocularis metacestodes. This diguanidino compound was effective against AE when administered intraperitoneally but not when applied orally. Thus, thiophene-diguanidino derivatives with improved bioavailability when administered orally could lead to treatment options against AE.

Evaluation of arylimidamides DB1955 and DB1960 as candidates against visceral leishmaniasis and Chagas' disease: in vivo efficacy, acute toxicity, pharmacokinetics, and toxicology studies.

Arylimidamides (AIAs) have shown outstanding in vitro potency against intracellular kinetoplastid parasites, and the AIA 2,5-bis[2-(2-propoxy)-4-(2-pyridylimino)aminophenyl]furan dihydrochloride (DB766) displayed good in vivo efficacy in rodent models of visceral leishmaniasis (VL) and Chagas' disease. In an attempt to further increase the solubility and in vivo antikinetoplastid potential of DB766, the mesylate salt of this compound and that of the closely related AIA 2,5-bis[2-(2-cyclopentyloxy)-4-(2-pyridylimino)aminophenyl]furan hydrochloride (DB1852) were prepared. These two mesylate salts, designated DB1960 and DB1955, respectively, exhibited dose-dependent activity in the murine model of VL, with DB1960 inhibiting liver parasitemia by 51% at an oral dose of 100 mg/kg/day × 5 and DB1955 reducing liver parasitemia by 57% when given by the same dosing regimen. In a murine Trypanosoma cruzi infection model, DB1960 decreased the peak parasitemia levels that occurred at 8 days postinfection by 46% when given orally at 100 mg/kg/day × 5, while DB1955 had no effect on peak parasitemia levels when administered by the same dosing regimen. Distribution studies revealed that these compounds accumulated to micromolar levels in the liver, spleen, and kidneys but to a lesser extent in the heart, brain, and plasma. A 5-day repeat-dose toxicology study with DB1960 and DB1955 was also conducted with female BALB/c mice, with the compounds administered orally at 100, 200, and 500 mg/kg/day. In the high-dose groups, DB1960 caused changes in serum chemistry, with statistically significant increases in serum blood urea nitrogen, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase levels, and a 21% decrease in body weight was observed in this group. These changes were consistent with microscopic findings in the livers and kidneys of the treated animals. The incidences of observed clinical signs (hunched posture, tachypnea, tremors, and ruffled fur) were more frequent in DB1960-treated groups than in those treated with DB1955. However, histopathological examination of tissue samples indicated that both compounds had adverse effects at all dose levels.

The adaptive potential of a survival artist: characterization of the in vitro interactions of Toxoplasma gondii tachyzoites with di-cationic compounds in human fibroblast cell cultures.

The impact of di-cationic pentamidine-analogues against Toxoplama gondii (Rh- and Me49-background) was investigated. The 72 h-growth assays showed that the arylimidamide DB750 inhibited the proliferation of tachyzoites of T. gondii Rh and T. gondii Me49 with an IC(50) of 0·11 and 0·13 µM, respectively. Pre-incubation of fibroblast monolayers with 1 µM DB750 for 12 h and subsequent culture in the absence of the drug also resulted in a pronounced inhibiton of parasite proliferation. However, upon 5-6 days of drug exposure, T. gondii tachyzoites adapted to the compound and resumed proliferation up to a concentration of 1·2 µM. Out of a set of 32 di-cationic compounds screened for in vitro activity against T. gondii, the arylimidamide DB745, exhibiting an IC(50) of 0·03 µM and favourable selective toxicity was chosen for further studies. DB745 also inhibited the proliferation of DB750-adapted T. gondii (IC(50)=0·07 µM). In contrast to DB750, DB745 also had a profound negative impact on extracellular non-adapted T. gondii tachyzoites, but not on DB750-adapted T. gondii. Adaptation of T. gondii to DB745 (up to a concentration of 0·46 µM) was much more difficult to achieve and feasible only over a period of 110 days. In cultures infected with DB750-adapted T. gondii seemingly intact parasites could occasionally be detected by TEM. This illustrates the astonishing capacity of T. gondii tachyzoites to adapt to environmental changes, at least under in vitro conditions, and suggests that DB745 could be an interesting drug candidate for further assessments in appropriate in vivo models.

In vitro efficacy of dicationic compounds and mefloquine enantiomers against Echinococcus multilocularis metacestodes.

The current chemotherapy of alveolar echinococcosis (AE) is based on benzimidazoles such as albendazole and has been shown to be parasitostatic rather than parasiticidal, requiring lifelong duration. Thus, new and more efficient treatment options are urgently needed. By employing a recently validated assay based on the release of functional phosphoglucose isomerase (PGI) from dying parasites, the activities of 26 dicationic compounds and of the (+)- and (-)-erythro-enantiomers of mefloquine were investigated. Initial screening of compounds was performed at 40 µM, and those compounds exhibiting considerable antiparasitic activities were also assessed at lower concentrations. Of the dicationic drugs, DB1127 (a diguanidino compound) with activities comparable to nitazoxanide was further studied. The activity of DB1127 was dose dependent and led to severe structural alterations, as visualized by electron microscopy. The (+)- and (-)-erythro-enantiomers of mefloquine showed similar dose-dependent effects, although higher concentrations of these compounds than of DB1127 were required for metacestode damage. In conclusion, of the drugs investigated here, the diguanidino compound DB1127 represents the most promising compound for further study in appropriate in vivo models for Echinococcus multilocularis infection.

In vitro trypanocidal activity of DB745B and other novel arylimidamides against Trypanosoma cruzi.

OBJECTIVES: As part of a search for new therapeutic opportunities to treat chagasic patients, in vitro efficacy studies were performed to characterize the activity of five novel arylimidamides (AIAs) against Trypanosoma cruzi. METHODS: The trypanocidal effect against T. cruzi was evaluated by light microscopy through the determination of IC50 values. Cytotoxicity was determined by MTT assays against mouse cardiomyocytes. RESULTS: Our data demonstrated the trypanocidal efficacy of these new compounds against bloodstream trypomastigotes and intracellular amastigotes, exhibiting IC50 values ranging from 0.015 to 2.5 and 0.02 to0.2 µM, respectively. One of the compounds, DB745B, was also highly active against a broad panel of isolates, including those naturally resistant to benznidazole. DB745B showed higher in vitro efficacy than the reference drugs used to treat patients (benznidazole IC50= 12.94 µM) and to prevent blood bank infection (gentian violet IC50= 30.6 µM). CONCLUSIONS: AIAs represent promising new chemical entities against T. cruzi and are also potential trypanocidal agents to prevent transfusion-associated Chagas' disease.

The efficacy of novel arylimidamides against Trypanosoma cruzi in vitro.

The present study aimed to determine the in vitro biological efficacy and selectivity of 7 novel AIAs upon bloodstream trypomastigotes and intracellular amastigotes of Trypanosoma cruzi. The biological activity of these aromatic compounds was assayed for 48 and 24 h against intracellular parasites and bloodstream forms of T. cruzi (Y strain), respectively. Additional assays were also performed to determine their potential use in blood banks by treating the bloodstream parasites with the compounds diluted in mouse blood for 24 h at 4°C. Toxicity against mammalian cells was evaluated using primary cultures of cardiac cells incubated for 24 and 48 h with the AIAs and then cellular death rates were determined by MTT colorimetric assays. Our data demonstrated the outstanding trypanocidal effect of AIAs against T. cruzi, especially DB1853, DB1862, DB1867 and DB1868, giving IC50 values ranging between 16 and 70 nanomolar against both parasite forms. All AIAs presented superior efficacy to benznidazole and some, such as DB1868, also demonstrated promising activity as a candidate agent for blood prophylaxis. The excellent anti-trypanosomal efficacy of these novel AIAs against T. cruzi stimulates further in vivo studies and justifies the screening of new analogues with the goal of establishing a useful alternative therapy for Chagas disease.

Experimental treatment of Neospora caninum-infected mice with the arylimidamide DB750 and the thiazolide nitazoxanide.

The cationic arylimidamide DB750 and the thiazolide nitazoxanide had been shown earlier to be effective against Neospora caninum tachyzoites in vitro with an IC(50) of 160nM and 4.23µM, respectively. In this study, we have investigated the effects of DB750 and nitazoxanide treatments of experimentally infected Balb/c mice, by applying the drugs either through the oral or the intraperitoneal route. In experiment 1, administration of DB750 (2mg/kg/day) and nitazoxanide (150mg/kg/day) started already 3 days prior to experimental infection of mice with 2×10(6) tachyzoites. Following infection, the drugs were further administrated daily for a period of 2 weeks, either orally or intraperitoneally. Intraperitoneal injection of DB750 was well tolerated by the mice, but treatment with nitazoxanide resulted in death of all mice within 3 days. Upon intraperitoneal application of DB750, the cerebral parasite load was significantly reduced compared to all other groups, while oral application of DB750 and nitazoxanide were not as effective, and resulted in significant weight loss. In experiment 2, mice were infected with 2×10(6) tachyzoites and at 2 weeks post-infection, DB750 (2mg/kg/day) was applied by intraperitoneal injections for 14 days. In the DB750-treated group, only 2 out of 12 mice succumbed to infection, compared to 7 out of 12 mice in the placebo-group. DB750 treatment also resulted in significantly reduced cerebral parasite burden, and reduced numbers of viable tachyzoites. Our data suggest that DB750 exerted its activity also after crossing the blood-brain barrier, and that this class of compounds could be promising for the control of N. caninum-associated disease.

Large, sequence-dependent effects on DNA conformation by minor groove binding compounds.

To determine what topological changes antiparasitic heterocyclic dications can have on kinetoplast DNA, we have constructed ligation ladders, with phased A5 and ATATA sequences in the same flanking sequence context, as models. Bending by the A5 tract is observed, as expected, while the ATATA sequence bends DNA very little. Complexes of these DNAs with three diamidines containing either furan, thiophene or selenophene groups flanked by phenylamidines were investigated along with netropsin. With the bent A5 ladder the compounds caused either a slight increase or decrease in the bending angle. Surprisingly, however, with ATATA all of the compounds caused significant bending, to values close to or even greater than the A5 bend angle. Results with a mixed cis sequence, which has one A5 and one ATATA, show that the compounds bend ATATA in the same direction as a reference A5 tract, that is, into the minor groove. These results are interpreted in terms of a groove structure for A5 which is largely pre-organized for a fit to the heterocyclic amidines. With ATATA the groove is intrinsically wider and must close to bind the compounds tightly. The conformational change at the binding site then leads to significant bending of the alternating DNA sequence.

Fetal Tracheal Occlusion Increases Lung Basal Cells via Increased Yap Signaling.

Fetal endoscopic tracheal occlusion (FETO) is an emerging surgical therapy for congenital diaphragmatic hernia (CDH). Ovine and rabbit data suggested altered lung epithelial cell populations after tracheal occlusion (TO) with transcriptomic signatures implicating basal cells. To test this hypothesis, we deconvolved mRNA sequencing (mRNA-seq) data and used quantitative image analysis in fetal rabbit lung TO, which had increased basal cells and reduced ciliated cells after TO. In a fetal mouse TO model, flow cytometry showed increased basal cells, and immunohistochemistry demonstrated basal cell extension to subpleural airways. Nuclear Yap, a known regulator of basal cell fate, was increased in TO lung, and Yap ablation on the lung epithelium abrogated TO-mediated basal cell expansion. mRNA-seq of TO lung showed increased activity of downstream Yap genes. Human lung specimens with congenital and fetal tracheal occlusion had clusters of subpleural basal cells that were not present in the control. TO increases lung epithelial cell nuclear Yap, leading to basal cell expansion.

Identification of diphenyl furan derivatives via high throughput and computational studies as ArgA inhibitors of Mycobacterium tuberculosis.

Microbial amino acid biosynthetic pathways are underexploited for the development of anti-bacterial agents. N-acetyl glutamate synthase (ArgA) catalyses the first committed step in L-arginine biosynthesis and is essential for M. tuberculosis growth. Here, we have purified and optimized assay conditions for the acetylation of l-glutamine by ArgA. Using the optimized conditions, high throughput screening was performed to identify ArgA inhibitors. We identified 2,5-Bis (2-chloro-4-guanidinophenyl) furan, a dicationic diaryl furan derivatives, as ArgA inhibitor, with a MIC99 values of 1.56 µM against M. tuberculosis. The diaryl furan derivative displayed bactericidal killing against both M. bovis BCG and M. tuberculosis. Inhibition of ArgA by the lead compound resulted in transcriptional reprogramming and accumulation of reactive oxygen species. The lead compound and its derivatives showed micromolar binding with ArgA as observed in surface plasmon resonance and tryptophan quenching experiments. Computational and dynamic analysis revealed that these scaffolds share similar binding site residues with L-arginine, however, with slight variations in their interaction pattern. Partial restoration of growth upon supplementation of liquid cultures with either L-arginine or N-acetyl cysteine suggests a multi-target killing mechanism for the lead compound. Taken together, we have identified small molecule inhibitors against ArgA enzyme from M. tuberculosis.

Arylimidamide DB766, a potential chemotherapeutic candidate for Chagas' disease treatment.

Chagas' disease, a neglected tropical illness for which current therapy is unsatisfactory, is caused by the intracellular parasite Trypanosoma cruzi. The goal of this work is to investigate the in vitro and in vivo effects of the arylimidamide (AIA) DB766 against T. cruzi. This arylimidamide exhibits strong trypanocidal activity and excellent selectivity for bloodstream trypomastigotes and intracellular amastigotes (Y strain), giving IC(50)s (drug concentrations that reduce 50% of the number of the treated parasites) of 60 and 25 nM, respectively. DB766 also exerts striking effects upon different parasite stocks, including those naturally resistant to benznidazole, and displays higher activity in vitro than the reference drugs. By fluorescent and transmission electron microscopy analyses, we found that this AIA localizes in DNA-enriched compartments and induces considerable damage to the mitochondria. DB766 effectively reduces the parasite load in the blood and cardiac tissue and presents efficacy similar to that of benznidazole in mouse models of T. cruzi infection employing the Y and Colombian strains, using oral and intraperitoneal doses of up to 100 mg/kg/day that were given after the establishment of parasite infection. This AIA ameliorates electrocardiographic alterations, reduces hepatic and heart lesions induced by the infection, and provides 90 to 100% protection against mortality, which is similar to that provided by benznidazole. Our data clearly show the trypanocidal efficacy of DB766, suggesting that this AIA may represent a new lead compound candidate to Chagas' disease treatment.

Novel arylimidamides for treatment of visceral leishmaniasis.

Arylimidamides (AIAs) represent a new class of molecules that exhibit potent antileishmanial activity (50% inhibitory concentration [IC(50)], <1 microM) against both Leishmania donovani axenic amastigotes and intracellular Leishmania, the causative agent for human visceral leishmaniasis (VL). A systematic lead discovery program was employed to characterize in vitro and in vivo antileishmanial activities, pharmacokinetics, mutagenicities, and toxicities of two novel AIAs, DB745 and DB766. They were exceptionally active (IC(50) < or = 0.12 microM) against intracellular L. donovani, Leishmania amazonensis, and Leishmania major and did not exhibit mutagenicity in an Ames screen. DB745 and DB766, given orally, produced a dose-dependent inhibition of liver parasitemia in two efficacy models, L. donovani-infected mice and hamsters. Most notably, DB766 (100 mg/kg of body weight/day for 5 days) reduced liver parasitemia in mice and hamsters by 71% and 89%, respectively. Marked reduction of parasitemia in the spleen (79%) and bone marrow (92%) of hamsters was also observed. Furthermore, these compounds distributed to target tissues (liver and spleen) and had a moderate oral bioavailability (up to 25%), a large volume of distribution, and an elimination half-life ranging from 1 to 2 days in mice. In a repeat-dose toxicity study of mice, there was no indication of liver or kidney toxicity for DB766 from serum chemistries, although mild hepatic cell eosinophilia, hypertrophy, and fatty changes were noted. These results demonstrated that arylimidamides are a promising class of molecules that possess good antileishmanial activity and desirable pharmacokinetics and should be considered for further preclinical development as an oral treatment for VL.

A Psychophysiological Model of Firearms Training in Police Officers: A Virtual Reality Experiment for Biocybernetic Adaptation.

Crucial elements for police firearms training include mastering very specific psychophysiological responses associated with controlled breathing while shooting. Under high-stress situations, the shooter is affected by responses of the sympathetic nervous system that can impact respiration. This research focuses on how frontal oscillatory brainwaves and cardiovascular responses of trained police officers (N = 10) are affected during a virtual reality (VR) firearms training routine. We present data from an experimental study wherein shooters were interacting in a VR-based training simulator designed to elicit psychophysiological changes under easy, moderate and frustrating difficulties. Outcome measures in this experiment include electroencephalographic and heart rate variability (HRV) parameters, as well as performance metrics from the VR simulator. Results revealed that specific frontal areas of the brain elicited different responses during resting states when compared with active shooting in the VR simulator. Moreover, sympathetic signatures were found in the HRV parameters (both time and frequency) reflecting similar differences. Based on the experimental findings, we propose a psychophysiological model to aid the design of a biocybernetic adaptation layer that creates real-time modulations in simulation difficulty based on targeted physiological responses.