Targeting the hSSB1-INTS3 Interface: A Computational Screening Driven Approach to Identify Potential Modulators.

Human single-stranded DNA binding protein 1 (hSSB1) forms a heterotrimeric complex, known as a sensor of single-stranded DNA binding protein 1 (SOSS1), in conjunction with integrator complex subunit 3 (INTS3) and C9ORF80. This sensory protein plays an important role in homologous recombination repair of double-strand breaks in DNA to efficiently recruit other repair proteins at the damaged sites. Previous studies have identified elevated hSSB1-mediated DNA repair activities in various cancers, highlighting its potential as an anticancer target. While prior efforts have focused on inhibiting hSSB1 by targeting its DNA binding domain, this study seeks to explore the inhibition of the hSSB1 function by disrupting its interaction with the key partner protein INTS3 in the SOSS1 complex. The investigative strategy entails a molecular docking-based screening of a specific compound library against the three-dimensional structure of INTS3 at the hSSB1 binding interface. Subsequent assessments involve in vitro analyses of protein-protein interaction (PPI) disruption and cellular effects through co-immunoprecipitation and immunofluorescence assays, respectively. Moreover, the study includes an evaluation of the structural stability of ligands at the INTS3 hot-spot site using molecular dynamics simulations. The results indicate a potential in vitro disruption of the INTS3-hSSB1 interaction by three of the tested compounds obtained from the virtual screening with one impacting the recruitment of hSSB1 and INTS3 to chromatin following DNA damage. To our knowledge, our results identify the first set of drug-like compounds that functionally target INTS3-hSSB1 interaction, and this provides the basis for further biophysical investigations that should help to speed up PPI inhibitor discovery.

Head and thorax elevation during cardiopulmonary resuscitation using circulatory adjuncts is associated with improved survival.

BACKGROUND: Survival after out-of-hospital cardiac arrest (OHCA) remains poor. A physiologically distinct cardiopulmonary resuscitation (CPR) strategy consisting of (1) active compression-decompression CPR and/or automated CPR, (2) an impedance threshold device, and (3) automated controlled elevation of the head and thorax (ACE) has been shown to improve neurological survival significantly versus conventional (C) CPR in animal models. This resuscitation device combination, termed ACE-CPR, is now used clinically. OBJECTIVES: To assess the probability of OHCA survival to hospital discharge after ACE-CPR versus C-CPR. METHODS: As part of a prospective registry study, 227 ACE-CPR OHCA patients were enrolled 04/2019-07/2020 from 6 pre-hospital systems in the United States. Individual C-CPR patient data (n = 5196) were obtained from three large published OHCA randomized controlled trials from high-performing pre-hospital systems. The primary study outcome was survival to hospital discharge. Secondary endpoints included return of spontaneous circulation (ROSC) and favorable neurological survival. Propensity-score matching with a 1:4 ratio was performed to account for imbalances in baseline characteristics. RESULTS: Irrespective of initial rhythm, ACE-CPR (n = 222) was associated with higher adjusted odds ratios (OR) of survival to hospital discharge relative to C-CPR (n = 860), when initiated in <11 min (3.28, 95 % confidence interval [CI], 1.55-6.92) and < 18 min (1.88, 95 % CI, 1.03-3.44) after the emergency call, respectively. Rapid use of ACE-CPR was also associated with higher probabilities of ROSC and favorable neurological survival. CONCLUSIONS: Compared with C-CPR controls, rapid initiation of ACE-CPR was associated with a higher likelihood of survival to hospital discharge after OHCA.

Faster time to automated elevation of the head and thorax during cardiopulmonary resuscitation increases the probability of return of spontaneous circulation.

OBJECTIVES: Resuscitation in the Head Up position improves outcomes in animals treated with active compression decompression cardiopulmonary resuscitation and an impedance threshold device (ACD + ITD CPR).We assessed impact of time to deployment of an automated Head Up position (AHUP) based bundle of care after out-of-hospital cardiac arrest on return of spontaneous circulation (ROSC). METHODS: Observational data were analyzed from a patient registry. Patients received treatment with 1) ACD + and/or automated CPR 2) an ITD and 3) an AHUP device. Probability of ROSC (ROSCprob) from the 9-1-1 call to AHUP device placement was assessed with a restricted cubic spline model and linear regression. RESULTS: Of 11 sites, 6 recorded the interval from 9-1-1 to AHUP device (n = 227). ROSCprobfor all rhythms was 34%(77/227). Median age (range) was 66 years (19-101) and 68% men. TheROSCprobfor shockable rhythms was 47%(18/38). Minutes from 9-1-1 to AHUP device (median, range) varied between sites: 1) 6.4(4,15), 2) 8.0(5,19), 3) 9.9(4, 12), 4) 14.1(6, 36), 5) 15.9(6, 34), 6) 19.0(8, 38),(p = 0.0001).ROSCprobalso varied; 1) 55.1%(16/29), 2) 60%(3/5), 3) 50%(3/6), 4) 22.7%(17/75), 5) 26.4%(9/34), and 6) 37.1%(29/78), (p = 0.019). For all rhythms between 4 and 12 min (n = 85),ROSCprobdeclined 5.6% for every minute elapsed (p = 0.024). For shockable rhythms, between 6 and 15 min (n = 23),ROSCprobdeclined 9.0% for every minute elapsed (p = 0.006). CONCLUSIONS: Faster time to deployment of an AHUP based bundle of care is associated with higher incidence of ROSC. This must be considered when evaluating and implementing this bundle.

Absence of Coronary Artery Calcium During Positron Emission Tomography Stress Testing in Patients Without Known Coronary Artery Disease Identifies Individuals With Very Low Risk of Cardiac Events.

BACKGROUND: Myocardial perfusion imaging, including positron emission tomography/computed tomography (PET/CT), is often used to assess for high-grade coronary artery disease (CAD) requiring revascularization. The use of coronary artery calcium (CAC) to predict risk of major adverse cardiovascular events in asymptomatic patients is accepted. However, little is known regarding the use of CAC in PET/CT patients without known CAD in identifying patients unlikely to need revascularization. Here, we determined whether the absence of CAC, using low-dose attenuation correction CT obtained during the PET/CT, identifies patients unlikely to undergo coronary revascularization within 90 days of a PET/CT. METHODS: Patients, without a history of CAD and no elevation in troponin, referred for PET/CT at Intermountain Medical Center were studied (n=5528). The presence of CAC was visually assessed using low-dose attenuation correction CT. The association between CAC and 90-day high-grade CAD and revascularization were assessed. Longer-term (up to 4 years) major adverse cardiovascular events, including all-cause death, myocardial infarction, and late revascularization (>90 days), were examined. RESULTS: There were 2510 (45.4%) patients in CAC-present group and 3018 (54.6%) patients in CAC-absent group. The CAC-absent group, compared with the CAC-present group, was less likely to undergo coronary angiography (3.4% versus 10.2%, P<0.0001), have high-grade CAD (0.5% versus 6.5%, P<0.0001), and receive revascularization (0.4% versus 5.8%, [adjusted odds ratio =0.09; 95% CI, 0.05-0.16]; P<0.0001). In patients with an ischemic burden >10%, the CAC-absent group was associated with reduced revascularization (P<0.0001). Longer-term major adverse cardiovascular events were lower in the CAC-absent (2.4%) compared with the CAC-present (6.9%) group (adjusted hazard ratio, 0.45 [95% CI, 0.34-0.60]; P<0.0001). CONCLUSIONS: The absence of CAC on low-dose attenuation correction CT identifies PET/CT patients unlikely to have high-grade CAD or require revascularization within 90 days and unlikely to experience longer-term major adverse cardiovascular events. The prognostic value of CAC, beyond ischemic burden, suggests its potential as a first-step screening tool in intermediate-risk patients to identify those who do not need coronary revascularization.

Implementation of a cardiac PET stress program: comparison of outcomes to the preceding SPECT era.

BACKGROUND: Cardiac positron emission testing (PET) is more accurate than single photon emission computed tomography (SPECT) at identifying coronary artery disease (CAD); however, the 2 modalities have not been thoroughly compared in a real-world setting. We conducted a retrospective analysis of 60-day catheterization outcomes and 1-year major adverse cardiovascular events (MACE) after the transition from a SPECT- to a PET-based myocardial perfusion imaging (MPI) program. METHODS: MPI patients at Intermountain Medical Center from January 2011-December 2012 (the SPECT era, n = 6,777) and January 2014-December 2015 (the PET era, n = 7,817) were studied. Outcomes studied were 60-day coronary angiography, high-grade obstructive CAD, left main/severe 3-vessel disease, revascularization, and 1-year MACE-revascularization (MACE-revasc; death, myocardial infarction [MI], or revascularization >60 days). RESULTS: Patients were 64 ± 13 years old; 54% were male and 90% were of European descent; and 57% represented a screening population (no prior MI, revascularization, or CAD). During the PET era, compared with the SPECT era, a higher percentage of patients underwent coronary angiography (13.2% vs. 9.7%, P < 0.0001), had high-grade obstructive CAD (10.5% vs. 6.9%, P < 0.0001), had left main or severe 3-vessel disease (3.0% vs. 2.3%, P = 0.012), and had coronary revascularization (56.7% vs. 47.1%, P = 0.0001). Similar catheterization outcomes were seen when restricted to the screening population. There was no difference in 1-year MACE-revasc (PET [5.8%] vs. SPECT [5.3%], P = 0.31). CONCLUSIONS: The PET-based MPI program resulted in improved identification of patients with high-grade obstructive CAD, as well as a larger percentage of revascularization, thus resulting in fewer patients undergoing coronary angiography without revascularization. FUNDING: This observational study was funded using internal departmental funds.

Analysis of tumour- and stroma-supplied proteolytic networks reveals a brain-metastasis-promoting role for cathepsin S.

Metastasis remains the most common cause of death in most cancers, with limited therapies for combating disseminated disease. While the primary tumour microenvironment is an important regulator of cancer progression, it is less well understood how different tissue environments influence metastasis. We analysed tumour-stroma interactions that modulate organ tropism of brain, bone and lung metastasis in xenograft models. We identified a number of potential modulators of site-specific metastasis, including cathepsin S as a regulator of breast-to-brain metastasis. High cathepsin S expression at the primary site correlated with decreased brain metastasis-free survival in breast cancer patients. Both macrophages and tumour cells produce cathepsin S, and only the combined depletion significantly reduced brain metastasis in vivo. Cathepsin S specifically mediates blood-brain barrier transmigration through proteolytic processing of the junctional adhesion molecule, JAM-B. Pharmacological inhibition of cathepsin S significantly reduced experimental brain metastasis, supporting its consideration as a therapeutic target for this disease.

Proteomic comparison of Hypnale hypnale (hump-nosed pit-viper) and Calloselasma rhodostoma (Malayan pit-viper) venoms.

Treatment of Hypnale hypnale bites with commercial antivenoms, even those raised against its sister taxon Calloselasma rhodostoma, has never been clinically successful. As these two genera have been separated for 20million years, we tested to see whether significant variations in venom had accumulated during this long period of evolutionary divergence, and thus could be responsible for the failure of antivenom. Proteomic analyses of C. rhodostoma and H. hypnale venom were performed using 1D and 2D PAGE as well as 2D-DIGE. C. rhodostoma venom was diverse containing large amounts of Disintegrin, Kallikrein, l-amino acid oxidase, Lectin, phospholipase A2 (acidic, basic and neutral) and Snake Venom Metalloprotease. In contrast, while H. hypnale also contained a wide range of toxin types, the venom was overwhelmingly dominated by two molecular weight forms of basic PLA2. 2D-DIGE (2-D Fluorescence Difference Gel Electrophoresis analysis) showed that even when a particular toxin class was shared between the two venoms, there were significant molecular weights or isoelectric point differences. This proteomic difference explains the past treatment failures with C. rhodostoma antivenom and highlights the need for a H. hypnale specific antivenom. BIOLOGICAL SIGNIFICANCE: These results have direct implications for the treatment of envenomed patients in Sri Lanka. The unusual venom profile of Hypnale hypnale underscores the biodiscovery potential of novel snake venoms.

Comparative genomics of early-diverging Brucella strains reveals a novel lipopolysaccharide biosynthesis pathway.

UNLABELLED: Brucella species are Gram-negative bacteria that infect mammals. Recently, two unusual strains (Brucella inopinata BO1T and B. inopinata-like BO2) have been isolated from human patients, and their similarity to some atypical brucellae isolated from Australian native rodent species was noted. Here we present a phylogenomic analysis of the draft genome sequences of BO1T and BO2 and of the Australian rodent strains 83-13 and NF2653 that shows that they form two groups well separated from the other sequenced Brucella spp. Several important differences were noted. Both BO1T and BO2 did not agglutinate significantly when live or inactivated cells were exposed to monospecific A and M antisera against O-side chain sugars composed of N-formyl-perosamine. While BO1T maintained the genes required to synthesize a typical Brucella O-antigen, BO2 lacked many of these genes but still produced a smooth LPS (lipopolysaccharide). Most missing genes were found in the wbk region involved in O-antigen synthesis in classic smooth Brucella spp. In their place, BO2 carries four genes that other bacteria use for making a rhamnose-based O-antigen. Electrophoretic, immunoblot, and chemical analyses showed that BO2 carries an antigenically different O-antigen made of repeating hexose-rich oligosaccharide units that made the LPS water-soluble, which contrasts with the homopolymeric O-antigen of other smooth brucellae that have a phenol-soluble LPS. The results demonstrate the existence of a group of early-diverging brucellae with traits that depart significantly from those of the Brucella species described thus far. IMPORTANCE: This report examines differences between genomes from four new Brucella strains and those from the classic Brucella spp. Our results show that the four new strains are outliers with respect to the previously known Brucella strains and yet are part of the genus, forming two new clades. The analysis revealed important information about the evolution and survival mechanisms of Brucella species, helping reshape our knowledge of this important zoonotic pathogen. One discovery of special importance is that one of the strains, BO2, produces an O-antigen distinct from any that has been seen in any other Brucella isolates to date.

Comparative genomics of early-diverging Brucella strains reveals a novel lipopolysaccharide biosynthesis pathway.

UNLABELLED: Brucella species are Gram-negative bacteria that infect mammals. Recently, two unusual strains (Brucella inopinata BO1(T) and B. inopinata-like BO2) have been isolated from human patients, and their similarity to some atypical brucellae isolated from Australian native rodent species was noted. Here we present a phylogenomic analysis of the draft genome sequences of BO1(T) and BO2 and of the Australian rodent strains 83-13 and NF2653 that shows that they form two groups well separated from the other sequenced Brucella spp. Several important differences were noted. Both BO1(T) and BO2 did not agglutinate significantly when live or inactivated cells were exposed to monospecific A and M antisera against O-side chain sugars composed of N-formyl-perosamine. While BO1(T) maintained the genes required to synthesize a typical Brucella O-antigen, BO2 lacked many of these genes but still produced a smooth LPS (lipopolysaccharide). Most missing genes were found in the wbk region involved in O-antigen synthesis in classic smooth Brucella spp. In their place, BO2 carries four genes that other bacteria use for making a rhamnose-based O-antigen. Electrophoretic, immunoblot, and chemical analyses showed that BO2 carries an antigenically different O-antigen made of repeating hexose-rich oligosaccharide units that made the LPS water-soluble, which contrasts with the homopolymeric O-antigen of other smooth brucellae that have a phenol-soluble LPS. The results demonstrate the existence of a group of early-diverging brucellae with traits that depart significantly from those of the Brucella species described thus far. IMPORTANCE: This report examines differences between genomes from four new Brucella strains and those from the classic Brucella spp. Our results show that the four new strains are outliers with respect to the previously known Brucella strains and yet are part of the genus, forming two new clades. The analysis revealed important information about the evolution and survival mechanisms of Brucella species, helping reshape our knowledge of this important zoonotic pathogen. One discovery of special importance is that one of the strains, BO2, produces an O-antigen distinct from any that has been seen in any other Brucella isolates to date.

Distribution of nitrogen fixation and nitrogenase-like sequences amongst microbial genomes.

BACKGROUND: The metabolic capacity for nitrogen fixation is known to be present in several prokaryotic species scattered across taxonomic groups. Experimental detection of nitrogen fixation in microbes requires species-specific conditions, making it difficult to obtain a comprehensive census of this trait. The recent and rapid increase in the availability of microbial genome sequences affords novel opportunities to re-examine the occurrence and distribution of nitrogen fixation genes. The current practice for computational prediction of nitrogen fixation is to use the presence of the nifH and/or nifD genes. RESULTS: Based on a careful comparison of the repertoire of nitrogen fixation genes in known diazotroph species we propose a new criterion for computational prediction of nitrogen fixation: the presence of a minimum set of six genes coding for structural and biosynthetic components, namely NifHDK and NifENB. Using this criterion, we conducted a comprehensive search in fully sequenced genomes and identified 149 diazotrophic species, including 82 known diazotrophs and 67 species not known to fix nitrogen. The taxonomic distribution of nitrogen fixation in Archaea was limited to the Euryarchaeota phylum; within the Bacteria domain we predict that nitrogen fixation occurs in 13 different phyla. Of these, seven phyla had not hitherto been known to contain species capable of nitrogen fixation. Our analyses also identified protein sequences that are similar to nitrogenase in organisms that do not meet the minimum-gene-set criteria. The existence of nitrogenase-like proteins lacking conserved co-factor ligands in both diazotrophs and non-diazotrophs suggests their potential for performing other, as yet unidentified, metabolic functions. CONCLUSIONS: Our predictions expand the known phylogenetic diversity of nitrogen fixation, and suggest that this trait may be much more common in nature than it is currently thought. The diverse phylogenetic distribution of nitrogenase-like proteins indicates potential new roles for anciently duplicated and divergent members of this group of enzymes.

Effects of exercise and antioxidant supplementation on endothelial gene expression.

BACKGROUND: The molecular mechanisms of exercise training induced cardiovascular protection are poorly understood. There is growing evidence that reactive oxygen species may be involved in a number of these adaptations and that antioxidants may be used to investigate this effect. OBJECTIVE: To determine the effects of exercise training and/or antioxidant supplementation on myocardial endothelium and vascular endothelium gene expression. METHODS: Male Wistar rats were divided into four groups: i) control; ii) exercise trained (90 min of treadmill running 4d per week, 14 weeks); iii) antioxidant-supplemented (α-tocopherol 1000 IU kg(-1) diet and α-lipoic acid 1.6 g kg(-1) diet, mixed with rat chow) and iv) exercise trained and antioxidant-supplemented. RESULTS: cDNA microarray analysis showed diverse expression changes in both left ventricular and coronary artery endothelial cells. In particular, RT-PCR analysis showed that a gene involved in cardiovascular disease progression, Ras homolog gene family member A, was down-regulated by exercise, and up-regulated by antioxidant supplementation in left ventricular endothelial cells. Furthermore, an important gene involved in inflammation, IL-6, was down-regulated by all treatments. CONCLUSIONS: Exercise training and/or antioxidant supplementation affects cardiac endothelial cell gene expression, and their effects on genes such as ras homolog gene family member A and IL-6 provides insight into the molecular mechanisms of their influences on cardiovascular diseases.

Proteolytic networks in cancer.

Proteases are important for multiple processes during malignant progression, including tumor angiogenesis, invasion and metastasis. Recent evidence reveals that tumor-promoting proteases function as part of an extensive multidirectional network of proteolytic interactions, in contrast to the unidirectional caspase cascade. These networks involve different constituents of the tumor microenvironment and key proteases, such as cathepsin B, urokinase-type plasminogen activator and several matrix metalloproteinases, occupy central nodes for amplifying proteolytic signals passing through the network. The proteolytic network interacts with other important signaling pathways in tumor biology, involving chemokines, cytokines, and kinases. Viewing these proteolytic interactions as a system of activating and inhibiting reactions provides insight into tumor biology and reveals relevant pharmaceutical targets. This review examines recent advances in understanding proteases in cancer and summarizes how the network of activity is co-opted to promote tumor progression.

HIF-1alpha in endurance training: suppression of oxidative metabolism.

During endurance training, exercising skeletal muscle experiences severe and repetitive oxygen stress. The primary transcriptional response factor for acclimation to hypoxic stress is hypoxia-inducible factor-1alpha (HIF-1alpha), which upregulates glycolysis and angiogenesis in response to low levels of tissue oxygenation. To examine the role of HIF-1alpha in endurance training, we have created mice specifically lacking skeletal muscle HIF-1alpha and subjected them to an endurance training protocol. We found that only wild-type mice improve their oxidative capacity, as measured by the respiratory exchange ratio; surprisingly, we found that HIF-1alpha null mice have already upregulated this parameter without training. Furthermore, untrained HIF-1alpha null mice have an increased capillary to fiber ratio and elevated oxidative enzyme activities. These changes correlate with constitutively activated AMP-activated protein kinase in the HIF-1alpha null muscles. Additionally, HIF-1alpha null muscles have decreased expression of pyruvate dehydrogenase kinase I, a HIF-1alpha target that inhibits oxidative metabolism. These data demonstrate that removal of HIF-1alpha causes an adaptive response in skeletal muscle akin to endurance training and provides evidence for the suppression of mitochondrial biogenesis by HIF-1alpha in normal tissue.

Assay optimization: a statistical design of experiments approach.

With the transition from manual to robotic HTS in the last several years, assay optimization has become a significant bottleneck. Recent advances in robotic liquid handling have made it feasible to reduce assay optimization timelines with the application of statistically designed experiments. When implemented, they can efficiently optimize assays by rapidly identifying significant factors, complex interactions, and nonlinear responses. This article focuses on the use of statistically designed experiments in assay optimization.

The role of HIF-1 in hypoxic response in the skeletal muscle.

During endurance training, exercising skeletal muscle experiences severe and repetitive oxygen stress, and the muscle's ability to cope with and improve its function through that stress is central to its role in the body. The primary transcriptional response factor for hypoxic adaptation is hypoxia inducible factor-1alpha (HIF-1alpha), which upregulates glycolysis and angiogenesis in response to low levels of tissue oxygenation. To examine the role of HIF-1alpha in endurance training, we have created mice specifically lacking skeletal muscle HIF-1alpha and subjected them to an endurance training protocol. We found that only wild type mice improve their oxidative capacity, as measured by the respiratory exchange ratio; surprisingly, we found that HIF-1alpha null mice have already upregulated this parameter without training. Furthermore, untrained HIF-1alpha null mice have an increased capillary to fiber ratio, and elevated oxidative enzyme activities. These changes correlate with constitutively activated AMP-activated protein kinase in the HIF-1alpha null muscles. Additionally, HIF-1alpha null muscles have decreased expression of pyruvate dehydrogenase kinase I, a HIF-1alpha target that inhibits oxidative metabolism. This data demonstrates that removal of HIF-1alpha causes an adaptive response in skeletal muscle akin to endurance training, and provides evidence for the suppression of mitochondrial biogenesis by HIF-1alpha in normal tissue.

Brain interface research for asynchronous control applications.

The Neil Squire Society has developed asynchronous, direct brain switches for self-paced control applications with mean activation rates of 73% and false positive error rates of 2%. This report summarizes our results to date, lessons learned, and current directions, including research into implanted brain interface designs.

Dietary Supplementation of Vitamin E and α-Lipoic Acid Upregulates Cell Growth and Signaling Genes in Rat Myocardium.

The efficacy of antioxidant supplementation in the prevention of cardiovascular disease appears equivocal, however the use of more potent antioxidant combinations than those traditionally used may exert a more positive effect. We have shown previously that supplementation of vitamin E and α-lipoic acid increases cardiac performance during post-ischemia reperfusion in older rats and increases Bcl-2 levels in endothelial cells. The purpose of this study was to examine the effects of vitamin E and α-lipoic acid supplementation on myocardial gene expression with a view to determine their mechanism of action. Young male rats received either a control (n=7) or vitamin E and α-lipoic acid supplemented diet (n=8) for 14 weeks. RNA from myocardial tissue was then amplified and samples were pooled within groups and competitively hybridized to 8.5K oligonucleotide rat microarrays. The relative expression of each gene was then compared to the control sample. Animals that received the antioxidant-supplemented diet exhibited upregulation (>1.5×) of 13 genes in the myocardium with 2 genes downregulated. Upregulated genes include those involved in cell growth and maintenance (LynB, Csf1r, Akt2, Tp53), cell signaling (LynB, Csf1r) and signal transduction (Pacsin2, Csf1r). Downregulated genes encode thyroid (Thrsp) and F-actin binding proteins (Nexilin).

Real-time control of a video game with a direct brain--computer interface.

Mason and Birch have developed a direct brain-computer interface for intermittent control of devices such as environmental control systems and neuroprotheses. This EEG-based brain switch, named the LF-ASD, has been used in several off-line studies, but little is known about its usability with real-world devices and computer applications. In this study, able-bodied individuals and people with high-level spinal injury used the LF-ASD brain switch to control a video game in real time. Both subject groups demonstrated switch activations varying from 30% to 78% and false-positive rates in the range of 0.5% to 2.2% over three 1-hour test sessions. These levels correspond to switch classification accuracies greater than 94% for all subjects. The results suggest that subjects with spinal cord injuries can operate the brain switch to the same ability as able-bodied subjects in a real-time control environment. These results support the findings of previous studies.

Loss of skeletal muscle HIF-1alpha results in altered exercise endurance.

The physiological flux of oxygen is extreme in exercising skeletal muscle. Hypoxia is thus a critical parameter in muscle function, influencing production of ATP, utilization of energy-producing substrates, and manufacture of exhaustion-inducing metabolites. Glycolysis is the central source of anaerobic energy in animals, and this metabolic pathway is regulated under low-oxygen conditions by the transcription factor hypoxia-inducible factor 1alpha (HIF-1alpha). To determine the role of HIF-1alpha in regulating skeletal muscle function, we tissue-specifically deleted the gene encoding the factor in skeletal muscle. Significant exercise-induced changes in expression of genes are decreased or absent in the skeletal-muscle HIF-1alpha knockout mice (HIF-1alpha KOs); changes in activities of glycolytic enzymes are seen as well. There is an increase in activity of rate-limiting enzymes of the mitochondria in the muscles of HIF-1alpha KOs, indicating that the citric acid cycle and increased fatty acid oxidation may be compensating for decreased flow through the glycolytic pathway. This is corroborated by a finding of no significant decreases in muscle ATP, but significantly decreased amounts of lactate in the serum of exercising HIF-1alpha KOs. This metabolic shift away from glycolysis and toward oxidation has the consequence of increasing exercise times in the HIF-1alpha KOs. However, repeated exercise trials give rise to extensive muscle damage in HIF-1alpha KOs, ultimately resulting in greatly reduced exercise times relative to wild-type animals. The muscle damage seen is similar to that detected in humans in diseases caused by deficiencies in skeletal muscle glycogenolysis and glycolysis. Thus, these results demonstrate an important role for the HIF-1 pathway in the metabolic control of muscle function.

Current trends in brain-computer interface research at the Neil Squire Foundation.

The Neil Squire Foundation (NSF) is a Canadian nonprofit organization whose purpose is to create opportunities for independence for individuals who have significant physical disabilities. Over the last ten years, our team in partnership with researchers at the Electrical and Computer Engineering Department, the University of British Columbia, has been working to develop a direct brain-controlled switch for individuals with significant physical disabilities. The NSF Brain Interface Project primarily focuses on the development of brain-computer interface switch technologies for intermittent (or asynchronous) control in natural environments. That is, technologies that will work when the User intends control but also remains in a stable off state when there is no intent to control. A prototype of such a switch has successfully been developed. This switch has demonstrated classification accuracies greater than 94%. The initial results are promising, but further research is required to improve switch accuracies and reliability and to test these switch technologies over a larger population of users and operating conditions. This paper provides an overview of the NSF brain-switch technologies and details our approach to future work in this area.