79 research outputs found

    Signal distortion from microelectrodes in clinical EEG acquisition systems

    Get PDF
    Many centers are now using high-density microelectrodes during traditional intracranial electroencephalography (iEEG) both for research and clinical purposes. These microelectrodes are FDA-approved and integrate into clinical EEG acquisition systems. However, the electrical characteristics of these electrodes are poorly described and clinical systems were not designed to use them; thus, it is possible that this shift into clinical practice could have unintended consequences. In this study, we characterized the impedance of over 100 commercial macro- and microelectrodes using electrochemical impedance spectroscopy (EIS) to determine how electrode properties could affect signal acquisition and interpretation. The EIS data were combined with the published specifications of several commercial EEG systems to design digital filters that mimic the behavior of the electrodes and amplifiers. These filters were used to analyze simulated brain signals that contain a mixture of characteristic features commonly observed in iEEG. Each output was then processed with several common quantitative EEG measurements. Our results show that traditional macroelectrodes had low impedances and produced negligible distortion of the original signal. Brain tissue and electrical wiring also had negligible filtering effects. However, microelectrode impedances were much higher and more variable than the macroelectrodes. When connected to clinical amplifiers, higher impedance electrodes produced considerable distortion of the signal at low frequencies (<60 Hz), which caused significant changes in amplitude, phase, variance and spectral band power. In contrast, there were only minimal changes to the signal content for frequencies above 100 Hz. In order to minimize distortion with microelectrodes, we determined that an acquisition system should have an input impedance of at least 1 GΩ, which is much higher than most clinical systems. These results show that it is critical to account for variations in impedance when analyzing EEG from different-sized electrodes. Data from microelectrodes may yield misleading results unless recorded with high-impedance amplifiers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98632/1/1741-2552_9_5_056007.pd

    Elevated Oestrogen Receptor Splice Variant ERαΔ5 Expression in Tumour-adjacent Hormone-responsive Tissue

    Get PDF
    Susceptibility to prostate or endometrial cancer is linked with obesity, a state of oestrogen excess. Oestrogen receptor (ER) splice variants may be responsible for the tissue-level of ER activity. Such micro-environmental regulation may modulate cancer initiation and/or progression mechanisms. Real-time reverse transcriptase (RT) polymerase chain reaction (PCR) was used to quantitatively assess the levels of four ER splice variants (ERαΔ3, ERαΔ5, ERβ2 and ERβ5), plus the full-length parent isoforms ERα and ERβ1, in high-risk [tumour-adjacent prostate (n = 10) or endometrial cancer (n = 9)] vs. low-risk [benign prostate (n = 12) or endometrium (n = 9)], as well as a comparison of UK (n = 12) vs. Indian (n = 15) benign prostate. All three tissue groups expressed the ER splice variants at similar levels, apart from ERαΔ5. This splice variant was markedly raised in all of the tumour-adjacent prostate samples compared to benign tissues. Immunofluorescence analysis for ERβ2 in prostate tissue demonstrated that such splice variants are present in comparable, if not greater, amounts as the parent full-length isoform. This small pilot study demonstrates the ubiquitous nature of ER splice variants in these tissue sites and suggests that ERαΔ5 may be involved in progression of prostate adenocarcinoma

    Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

    Get PDF

    Lawson criterion for ignition exceeded in an inertial fusion experiment

    Get PDF
    For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

    Vancomycin plus nafcillin salvage for the treatment of persistent methicillin-resistant Staphylococcus aureus bacteremia following daptomycin failure: a case report and literature review

    No full text
    Background: Evidence supporting beta-lactam plus vancomycin synergy for methicillin-resistant Staphylococcus aureus (MRSA) continues to grow. Current in vivo evidence demonstrates that combination therapy is associated with shorter time to blood sterilization than vancomycin monotherapy. However, this combination has not been reported as salvage therapy for persistent MRSA bacteremia. Case report: We report a case of an 81-year-old male who was successfully treated with vancomycin plus nafcillin after failing vancomycin monotherapy, daptomycin monotherapy, and daptomycin plus gentamicin combination therapy. The patient originally presented with sepsis from a suspected urinary tract infection. Blood cultures drawn on days 1, 3, 5, 15, 19, 23, and 28 remained positive for MRSA despite multiple antimicrobial therapy changes. On day 29, therapy was changed to vancomycin plus nafcillin. Blood cultures drawn on day 32 remained negative. After 11 days, nafcillin was changed to piperacillin–tazobactam due to an infected decubitus ulcer. The combination was continued for 42 days after achieving blood sterility, 71 days after the patient originally presented. Evidence regarding salvage therapy for persistent bacteremia is sparse and is limited to case reports and case series. Conclusion: This case report supports that vancomycin plus an anti-staphylococcal beta-lactam combination should be further studied as salvage therapy for persistent MRSA bacteremia

    High-altitude ancestry and hypoxia acclimation have distinct effects on exercise capacity and muscle phenotype in deer mice

    Get PDF
    The hypoxic and cold environment at high altitudes requires that small mammals sustain high rates of O2 transport for exercise and thermogenesis while facing a diminished O2 availability. We used laboratory born and -raised deer mice (Peromyscus maniculatus) from highland and lowland populations to determine the interactive effects of ancestry and hypoxia acclimation on exercise performance. Maximal O2 consumption (VO2max ) during exercise in hypoxia increased after hypoxia acclimation (equivalent to the hypoxia at ~4,300 m elevation for 6–8 wk) and was consistently greater in highlanders than in lowlanders. V̇O2max during exercise in normoxia was not affected by ancestry or acclimation. Highlanders also had consistently greater capillarity, oxidative fiber density, and maximal activities of oxidative enzymes (cytochrome c oxidase and citrate synthase) in the gastrocnemius muscle, lower lactate dehydrogenase activity in the gastrocnemius, and greater cytochrome c oxidase activity in the diaphragm. Hypoxia acclimation did not affect any of these muscle traits. The unique gastrocnemius phenotype of highlanders was associated with higher mRNA and protein abundances of peroxisome proliferator-activated receptor γ (PPARγ). Vascular endothelial growth factor (VEGFA) transcript abundance was lower in highlanders, and hypoxia acclimation reduced the expression of numerous genes that regulate angiogenesis and energy metabolism, in contrast to the observed population differences in muscle phenotype. Lowlanders exhibited greater increases in blood hemoglobin content, hematocrit, and wet lung mass (but not dry lung mass) than highlanders after hypoxia acclimation. Genotypic adaptation to high altitude, therefore, improves exercise performance in hypoxia by mechanisms that are at least partially distinct from those underlying hypoxia acclimation

    Association of Psoriasis with Psychiatric Hospitalization in United States Children and Adults

    No full text
    © 2019 S. Karger AG, Basel. All rights reserved. Background: Psoriasis is associated with psychosocial distress. Little is known about the relationship between psoriasis and mental health (MH) emergencies. Objective: To examine the associations of psoriasis and MH hospitalizations in the USA. Methods: Data from the 2002-2012 National Inpatient Sample were analyzed, including an approximately 20% sample of all US hospitalizations (n = 87,053,155 children and adults). Results: Hospitalization for MH disorders occurred more commonly in those with psoriasis compared to those without psoriasis (4.04 vs. 2.21%). In multivariable logistic regression models, psoriasis was associated with higher odds of admission for any MH disorder overall (adjusted odds ratio [95% confidence interval]: 2.32 [2.24-2.41]), as well as 9 of the 15 MH-specific disorders examined. Associated MH disorders included: anxiety, schizophrenia, personality disorder, depression, substance use disorders, history of MH disorder, alcohol-related disorders, adjustment disorders, and cognitive disorders. Children with versus those without psoriasis were also more likely to have a primary hospitalization for any MH disorder (2.82 [2.24-3.56]). Psoriasis inpatients were also more likely to have a primary hospitalization for any MH disorder compared to those with alopecia areata (1.99 [1.45-2.74]) or hidradenitis suppurativa (3.97 [3.49-4.52]). Psoriasis patients hospitalized with any MH disorder had higher mean [95% confidence interval] cost of inpatient care (USD 11,004 [10,846-11,241] vs. 9,547 [8,730-10,364]; p \u3c 0.0001) compared to those without psoriasis, with USD 1,610,860 excess costs annually, with the majority of the costs coming from depression and mood disorders. Conclusions: Children and adults with psoriasis had increased hospitalization for multiple MH disorders, which were associated with a considerable financial burden

    Placebo responses in randomized controlled trials for systemic therapy in atopic dermatitis: A systematic review and meta-analysis

    No full text
    © 2019 American Academy of Dermatology, Inc. Background: Atopic dermatitis (AD) has a variable disease course and intermittent triggers, and responses to topical therapy vary, potentially affecting the magnitude of the placebo response in AD trials. Objective: To determine the predictors of increased placebo response in randomized controlled trials of AD. Methods: We performed a systematic review and meta-analysis of randomized controlled trials for systemic therapy in AD published during 2007-2018. We searched the Cochrane Library, Medline, Embase, Global Resource for EczemA Trials (GREAT), Literature of the Latin American and Caribbean Health Sciences (LILACS), and Scopus. Two authors performed study selection and data extraction. Multivariable mixed models were constructed for Cohen D of Eczema Area and Severity Index (EASI), SCORing Atopic Dermatitis (SCORAD), numeric rating scale (NRS)–itch and visual analog scale (VAS)–itch, and Dermatology Life Quality Index (DLQI). Results: Overall, 64 trials were included. Use of concomitant topical therapy prescriptions, study duration ≥3 months, and fewer treatment arms were associated with an increased placebo response for EASI, NRS- and VAS-itch, and DLQI. For EASI, the placebo response was increased in studies with a higher proportion of male patients, mild-moderate mean baseline EASI scores, and no blinding. For NRS-itch, and VRS-itch, higher placebo responses were associated with higher proportions of male patients and moderate-severe mean itch scores at baseline. Conclusion: Placebo responses can be reduced in clinical trials of systemic therapy in AD by incorporating double- and triple-blinding, balancing the sex distribution of patients, disallowing concomitant use of prescription topical therapy, and having shorter study durations
    corecore