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Wang Q, Jiao W, Yu R, Johnson MT, Zhang Y. Modeling of Human Welders’ Operations in Virtual Reality Human–Robot Interaction. IEEE Robot Autom Lett 2019. [DOI: 10.1109/lra.2019.2921928] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Johnson MT, Smith KC, Tsai LL. Vaginal spindle cell epithelioma: A first complete MRI and histopathologic description. Clin Imaging 2018; 50:181-184. [PMID: 29604603 DOI: 10.1016/j.clinimag.2018.03.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/20/2018] [Accepted: 03/26/2018] [Indexed: 11/19/2022]
Abstract
Spindle cell epithelioma of the vagina is a benign entity with fewer than sixty cases described in the literature, and only two with limited imaging findings, since the early 1950s. Early pathology literature suggested the lesions were mixed tumors of myoepithelial origin, but subsequent studies have found relatively few immunohistochemical characteristics in common with other mixed cell tumors. More recently, Mullerian, urogenital sinus epithelial, and pluripotential cell origins have been proposed. Given lesion rarity and a typical lack of imaging before excision, the imaging appearance of vaginal spindle cell epitheliomas has not been fully described in the radiology literature, and without comprehensive pathology correlation. The authors describe a case of spindle cell epithelioma in a 54-year-old woman which was incidentally discovered on MRI performed for uterine fibroid embolization planning. Pathology and immunohistochemistry confirmed the diagnosis.
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Affiliation(s)
- Michael T Johnson
- Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, United States.
| | - Kristin C Smith
- Department of Pathology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, United States.
| | - Leo L Tsai
- Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, United States.
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Berry J, Kolb A, Schroeder J, Johnson MT. Jaw Rotation in Dysarthria Measured With a Single Electromagnetic Articulography Sensor. Am J Speech Lang Pathol 2017; 26:596-610. [PMID: 28654942 DOI: 10.1044/2017_ajslp-16-0104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/22/2016] [Indexed: 06/07/2023]
Abstract
PURPOSE This study evaluated a novel method for characterizing jaw rotation using orientation data from a single electromagnetic articulography sensor. This method was optimized for clinical application, and a preliminary examination of clinical feasibility and value was undertaken. METHOD The computational adequacy of the single-sensor orientation method was evaluated through comparisons of jaw-rotation histories calculated from dual-sensor positional data for 16 typical talkers. The clinical feasibility and potential value of single-sensor jaw rotation were assessed through comparisons of 7 talkers with dysarthria and 19 typical talkers in connected speech. RESULTS The single-sensor orientation method allowed faster and safer participant preparation, required lower data-acquisition costs, and generated less high-frequency artifact than the dual-sensor positional approach. All talkers with dysarthria, regardless of severity, demonstrated jaw-rotation histories with more numerous changes in movement direction and reduced smoothness compared with typical talkers. CONCLUSIONS Results suggest that the single-sensor orientation method for calculating jaw rotation during speech is clinically feasible. Given the preliminary nature of this study and the small participant pool, the clinical value of such measures remains an open question. Further work must address the potential confound of reduced speaking rate on movement smoothness.
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Affiliation(s)
- Jeff Berry
- Department of Speech Pathology & Audiology, Marquette University, Milwaukee, WI
| | - Andrew Kolb
- Department of Electrical & Computer Engineering, Marquette University, Milwaukee, WI
| | - James Schroeder
- Department of Electrical & Computer Engineering, Marquette University, Milwaukee, WI
| | - Michael T Johnson
- Department of Electrical & Computer Engineering, Marquette University, Milwaukee, WI
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Scheifele PM, Johnson MT, Fry M, Hamel B, Laclede K. Vocal classification of vocalizations of a pair of Asian small-clawed otters to determine stress. J Acoust Soc Am 2015; 138:EL105-EL109. [PMID: 26233050 DOI: 10.1121/1.4922768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Asian Small-Clawed Otters (Aonyx cinerea) are a small, protected but threatened species living in freshwater. They are gregarious and live in monogamous pairs for their lifetimes, communicating via scent and acoustic vocalizations. This study utilized a hidden Markov model (HMM) to classify stress versus non-stress calls from a sibling pair under professional care. Vocalizations were expertly annotated by keepers into seven contextual categories. Four of these-aggression, separation anxiety, pain, and prefeeding-were identified as stressful contexts, and three of them-feeding, training, and play-were identified as non-stressful contexts. The vocalizations were segmented, manually categorized into broad vocal type call types, and analyzed to determine signal to noise ratios. From this information, vocalizations from the most common contextual categories were used to implement HMM-based automatic classification experiments, which included individual identification, stress vs non-stress, and individual context classification. Results indicate that both individual identity and stress vs non-stress were distinguishable, with accuracies above 90%, but that individual contexts within the stress category were not easily separable.
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Affiliation(s)
- Peter M Scheifele
- FETCHLAB, Department of Audiology, University of Cincinnati, 3202 Eden Avenue, Cincinnati, Ohio 45267, USA
| | - Michael T Johnson
- Electrical and Computer Engineering Department, Marquette University, 1515 West Wisconsin Avenue, Milwaukee, Wisconsin 53233, USA
| | - Michelle Fry
- Newport Aquarium, 1 Aquarium Way, Newport, Kentucky 41071, USA , , , ,
| | - Benjamin Hamel
- Electrical and Computer Engineering Department, Marquette University, 1515 West Wisconsin Avenue, Milwaukee, Wisconsin 53233, USA
| | - Kathryn Laclede
- FETCHLAB, Department of Audiology, University of Cincinnati, 3202 Eden Avenue, Cincinnati, Ohio 45267, USA
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Yu C, Wójcicki KK, Loizou PC, Hansen JHL, Johnson MT. Evaluation of the importance of time-frequency contributions to speech intelligibility in noise. J Acoust Soc Am 2014; 135:3007-16. [PMID: 24815280 PMCID: PMC4032418 DOI: 10.1121/1.4869088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 12/27/2013] [Accepted: 03/07/2014] [Indexed: 05/24/2023]
Abstract
Recent studies on binary masking techniques make the assumption that each time-frequency (T-F) unit contributes an equal amount to the overall intelligibility of speech. The present study demonstrated that the importance of each T-F unit to speech intelligibility varies in accordance with speech content. Specifically, T-F units are categorized into two classes, speech-present T-F units and speech-absent T-F units. Results indicate that the importance of each speech-present T-F unit to speech intelligibility is highly related to the loudness of its target component, while the importance of each speech-absent T-F unit varies according to the loudness of its masker component. Two types of mask errors are also considered, which include miss and false alarm errors. Consistent with previous work, false alarm errors are shown to be more harmful to speech intelligibility than miss errors when the mixture signal-to-noise ratio (SNR) is below 0 dB. However, the relative importance between the two types of error is conditioned on the SNR level of the input speech signal. Based on these observations, a mask-based objective measure, the loudness weighted hit-false, is proposed for predicting speech intelligibility. The proposed objective measure shows significantly higher correlation with intelligibility compared to two existing mask-based objective measures.
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Affiliation(s)
- Chengzhu Yu
- Department of Electrical Engineering, Erik Jonsson School of Enigneering and Computer Science, University of Texas at Dallas, Richardson, Texas 75083
| | - Kamil K Wójcicki
- Department of Electrical Engineering, Erik Jonsson School of Enigneering and Computer Science, University of Texas at Dallas, Richardson, Texas 75083
| | - Philipos C Loizou
- Department of Electrical Engineering, Erik Jonsson School of Enigneering and Computer Science, University of Texas at Dallas, Richardson, Texas 75083
| | - John H L Hansen
- Department of Electrical Engineering, Erik Jonsson School of Enigneering and Computer Science, University of Texas at Dallas, Richardson, Texas 75083
| | - Michael T Johnson
- Speech and Signal Processing Laboratory, Marquette University, 1515 West Wisconsin Avenue, Milwaukee, Wisconsin 53201-1881
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Tan N, McClure TD, Tarnay C, Johnson MT, Lu DS, Raman SS. Women seeking second opinion for symptomatic uterine leiomyoma: role of comprehensive fibroid center. J Ther Ultrasound 2014; 2:3. [PMID: 25512867 PMCID: PMC4265989 DOI: 10.1186/2050-5736-2-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/30/2014] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE The objective of the study was to describe our early experience with a comprehensive uterine fibroid center and report our results in women seeking a second opinion for management of symptomatic uterine leiomyoma. METHODS We performed a HIPAA-complaint, IRB-approved retrospective study of women seeking second opinion for management of uterine fibroids at our multidisciplinary fibroid treatment center in a tertiary care facility from July 2008 to August 2011. After a review of patients' history, physical examination, and magnetic resonance imaging (MRI) findings, treatment options were discussed which included conservative management, uterine-preserving options, and hysterectomy. We performed Fisher's exact test for categorical variables between the cohort that did or did not undergo a uterine-preserving treatment. Differences were considered significant at p < 0.05. RESULTS The mean age of the 205 patient study cohort was 43.8 years (SD 7.5). One hundred sixty-two (79.0%) patients had no prior therapy. Based on MRI, one or more fibroids were detected in 178/205 (86.8%), adenomyosis in 8/205 (3.9%), and a combination of fibroid and nonfibroid condition (i.e., adenomyosis, endometrial polyp) in 18/205 (8.8%). In those who desired to transition their care to our institution (n = 109), 85 patients underwent 90 interventions: 39 MRgFUS (magnetic resonance-guided high-intensity focused ultrasound surgery), 14 UAE (uterine artery embolization), 25 myomectomies, 8 hysterectomies, 3 polypectomies, and 1 endometrial ablation. Five patients had two procedures. Intramural and subserosal fibroids were most commonly treated with MRgFUS followed by myomectomy and then UAE; in contrast, pedunculated fibroids were frequently managed with myomectomy. CONCLUSIONS Multidisciplinary fibroid evaluation may facilitate the increase use of less invasive options over hysterectomy for symptomatic fibroid treatment.
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Affiliation(s)
- Nelly Tan
- Department of Radiology, University of California, 757 Westwood Blvd, Los Angeles, CA 90095, USA
| | - Timothy D McClure
- Department of Radiology, University of California, 757 Westwood Blvd, Los Angeles, CA 90095, USA
| | - Christopher Tarnay
- Department of Obstetrics and Gynecology, University of California, 757 Westwood Blvd, Los Angeles, CA 90095, USA
| | - Michael T Johnson
- Department of Obstetrics and Gynecology, University of California, 757 Westwood Blvd, Los Angeles, CA 90095, USA
| | - David Sk Lu
- Department of Radiology, University of California, 757 Westwood Blvd, Los Angeles, CA 90095, USA
| | - Steven S Raman
- Department of Radiology, University of California, 757 Westwood Blvd, Los Angeles, CA 90095, USA
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Ji A, Johnson MT, Walsh EJ, McGee J, Armstrong DL. Discrimination of individual tigers (Panthera tigris) from long distance roars. J Acoust Soc Am 2013; 133:1762-1769. [PMID: 23464045 DOI: 10.1121/1.4789936] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper investigates the extent of tiger (Panthera tigris) vocal individuality through both qualitative and quantitative approaches using long distance roars from six individual tigers at Omaha's Henry Doorly Zoo in Omaha, NE. The framework for comparison across individuals includes statistical and discriminant function analysis across whole vocalization measures and statistical pattern classification using a hidden Markov model (HMM) with frame-based spectral features comprised of Greenwood frequency cepstral coefficients. Individual discrimination accuracy is evaluated as a function of spectral model complexity, represented by the number of mixtures in the underlying Gaussian mixture model (GMM), and temporal model complexity, represented by the number of sequential states in the HMM. Results indicate that the temporal pattern of the vocalization is the most significant factor in accurate discrimination. Overall baseline discrimination accuracy for this data set is about 70% using high level features without complex spectral or temporal models. Accuracy increases to about 80% when more complex spectral models (multiple mixture GMMs) are incorporated, and increases to a final accuracy of 90% when more detailed temporal models (10-state HMMs) are used. Classification accuracy is stable across a relatively wide range of configurations in terms of spectral and temporal model resolution.
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Affiliation(s)
- An Ji
- Department of Electrical and Computer Engineering, Marquette University, 1515 West Wisconsin Avenue, Milwaukee, Wisconsin 53233, USA
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Scheifele PM, Johnson MT, Byrne DC, Clark JG, Vandlik A, Kretschmer LW, Sonstrom KE. Noise impacts from professional dog grooming forced-air dryers. Noise Health 2012; 14:224-6. [PMID: 23117536 DOI: 10.4103/1463-1741.102958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
This study was designed to measure the sound output of four commonly used brands of forced-air dryers used by dog groomers in the United States. Many dog groomers have questions about the effect of this exposure on their hearing, as well as on the hearing of the dogs that are being groomed. Readings taken from each dryer at 1 meter (the likely distance of the dryer from the groomer and the dog) showed average levels ranging from 105.5 to 108.3 dB SPL or 94.8 to 108.0 dBA. Using the 90 dBA criterion required by the US Occupational Safety and Health Administration, dog groomers/bathers are at risk if exposure to the lowest intensity dryer (94.8 dBA) exceeds 4 hours per day. If the more stringent 85 dBA criterion and 3 dB tradeoff is applied, less than one hour of exposure is permissible in an 8 hour day. Cautions are recommended for any persons exposed to noise from forced-air dryers.
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Affiliation(s)
- Peter M Scheifele
- College of Allied Health Sciences and Medicine, Communication Sciences and Disorders Department, University of Cincinnati, OH 45267-0379, USA.
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Johnson MT, Yamanaka TT, Fraidenburg DR, Kane SP. Benzodiazepine misadventure in acute alcohol withdrawal: the transition from delirium tremens to ICU delirium. J Anesth 2012; 27:135-6. [DOI: 10.1007/s00540-012-1458-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022]
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Scheifele PM, Johnson MT, Kretschmer L, Clark JG, Kemper D, Potty G. Ambient habitat noise and vibration at the Georgia Aquarium. J Acoust Soc Am 2012; 132:EL88-EL94. [PMID: 22894321 DOI: 10.1121/1.4734387] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Underwater and in-air noise evaluations were completed in performance pool systems at Georgia Aquarium under normal operating conditions and with performance sound tracks playing. Ambient sound pressure levels at in-pool locations, with corresponding vibration measures from life support system (LSS) pumps, were measured in operating configurations, from shut down to full operation. Results indicate noise levels in the low frequency ranges below 100 Hz were the highest produced by the LSS relative to species hearing thresholds. The LSS had an acoustic impact of about 10 dB at frequencies up to 700 Hz, with a 20 dB re 1 μPa impact above 1000 Hz.
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Affiliation(s)
- P M Scheifele
- Department of Communication Sciences and Disorders and College of Medicine, University of Cincinnati, 3202 Eden Avenue, Cincinnati, Ohio 45267-0379, USA.
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Micek S, Johnson MT, Reichley R, Kollef MH. An institutional perspective on the impact of recent antibiotic exposure on length of stay and hospital costs for patients with gram-negative sepsis. BMC Infect Dis 2012; 12:56. [PMID: 22414209 PMCID: PMC3325861 DOI: 10.1186/1471-2334-12-56] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 03/13/2012] [Indexed: 11/12/2022] Open
Abstract
Background Prior antibiotic exposure has been associated with the emergence of antibiotic resistance in subsequent bacterial infections, whose outcomes are typically worse than similar infections with more antibiotic susceptible infections. The influence of prior antibiotic exposure on hospital length of stay (LOS) and costs in patients with severe sepsis or septic shock attributed to Gram-negative bacteremia has not been previously examined. Methods A retrospective cohort study of hospitalized patients (January 2002-December 2007) was performed at Barnes-Jewish Hospital, a 1200-bed urban teaching hospital. Patients with Gram-negative bacteremia complicated by severe sepsis or septic shock had data abstraction from computerized medical records. We examined a consecutive cohort of 754 subjects (mean age 59.3 ± 16.3 yrs, mean APACHE II 23.7 ± 6.7). Results Escherichia coli (30.8%), Klebsiella pneumoniae (23.2%), and Pseudomonas aeruginosa (17.6%) were the most common organisms isolated from blood cultures. 310 patients (41.1%) had exposure to antimicrobial agents in the previous 90 days. Patients with recent antibiotic exposure had greater inappropriate initial antimicrobial therapy (45.4% v. 21.2%; p < 0.001) and hospital mortality (51.3% v. 34.0%; p < 0.001) compared to patients without recent antibiotic exposure. The unadjusted median LOS (25th percentile, 75th percentile) following sepsis onset in patients with prior antimicrobial exposure was 13.0 days (5.0 days, 24.0 days) compared to 8.0 days (5.0 days, 14.0 days) in those without prior antimicrobial exposure (p < 0.001). In a Cox model controlling for multiple confounders, prior antibiotic exposure independently correlated with remaining hospitalized (Adjusted hazard ratio: 1.473, 95% CI: 1.297-1.672, p < 0.001). Adjusting for potential confounders indicated that prior antibiotic exposure independently increased median attributable LOS by 5.0 days. Similarly, total hospital costs following sepsis onset was significantly greater among patients with prior antimicrobial exposure (median values: $94,737 v. $21,329; p < 0.001). Conclusions Recent antibiotic exposure is associated with increased LOS and hospital costs in Gram-negative bacteremia complicated by severe sepsis or septic shock. Clinicians and hospital administrators should consider the potential impact of recent antibiotic exposure when formulating empiric treatment decisions for patients with serious infections attributed to Gram-negative bacteria.
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Affiliation(s)
- Scott Micek
- Pharmacy Department, Barnes-Jewish Hospital, St. Louis, Missouri, USA
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Johnson MT, McCammon CA, Mullins ME, Halcomb SE. Evaluation of a Simplified N-Acetylcysteine Dosing Regimen for the Treatment of Acetaminophen Toxicity. Ann Pharmacother 2011; 45:713-20. [DOI: 10.1345/aph.1p613] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND: Acetaminophen overdose is the most common pharmaceutical poisoning in the US. The labeled dosing regimen for Acetadote, the only intravenous N-acetylcysteine (IV-NAC) product approved by the Food and Drug Administration (FDA) for treatment of acetaminophen toxicity, is a complex 3-step process that produces frequent medication errors. We have been using an off-label, uncomplicated dosing regimen consisting of a standard preparation of IV-NAC 30 g in 1 L of 5% dextrose in water, with a 150-mg/kg loading dose administered over 1 hour followed by an infusion of 14 mg/kg/h for 20 hours. OBJECTIVE: To evaluate the frequency of medication errors, resolution of hepatotoxicity, and tolerability of the protocol used in our institution for treatment of acetaminophen toxicity. METHODS: This single-center, retrospective chart review evaluated patients receiving IV-NAC for acetaminophen toxicity from August 2006 to August 2008. Charts were reviewed for prescribing practices, dosing errors, and clinical outcomes. RESULTS: Among 70 patients who met inclusion criteria, 35 medication errors occurred, including 22 administration errors and 13 protocol initiation errors. The frequency of administration errors was 13.5 errors per 100 administration interventions. Loading dose errors were most common with 11 rate-related and 8 dose-related errors. Interruptions longer than 60 minutes occurred in only 3 patients. No adverse outcomes were associated with medication errors. The mean (SD) duration of therapy was 25.6 hours (n = 60 pts. [17.8], range 1-76.5), and mean length of stay was 2.99 days ([3.82], range 0.1-25.7). All patients with hepatotoxicity (aspartate aminotransferase >1000 units/L) due to acute acetaminophen toxicity had resolution of the toxicity and were successfully discharged. CONCLUSIONS: This single intravenous bag protocol is effective and well tolerated, and there is infrequent interruption of therapy. The overall rate of administration errors is similar to that in reports on the FDA regimen; thus, our protocol may be an acceptable alternative.
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Affiliation(s)
- Michael T Johnson
- Michael T Johnson PharmD, at time of study, PGY-2 Pharmacotherapy Resident, Department of Pharmacy, Barnes-Jewish Hospital, St. Louis, MO; now, Clinical Pharmacist, Clinical Assistant Professor, Department of Pharmacy Practice, College of Pharmacy, University of Illinois, Chicago, IL
| | - Craig A McCammon
- Craig A McCammon PharmD BCPS, Clinical Pharmacist, Department of Pharmacy, Barnes-Jewish Hospital
| | - Michael E Mullins
- Michael E Mullins MD FACEP, Assistant Professor, Division of Emergency Medicine, Washington University, St. Louis
| | - S Eliza Halcomb
- S Eliza Halcomb MD, Assistant Professor, Division of Emergency Medicine, School of Medicine, Washington University
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Zhang WQ, He L, Deng Y, Liu J, Johnson MT. Time–Frequency Cepstral Features and Heteroscedastic Linear Discriminant Analysis for Language Recognition. ACTA ACUST UNITED AC 2011. [DOI: 10.1109/tasl.2010.2047680] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
This paper presents an advanced method to acoustically assess animal abundance. The framework combines supervised classification (song-type and individual identity recognition), unsupervised classification (individual identity clustering), and the mark-recapture model of abundance estimation. The underlying algorithm is based on clustering using hidden Markov models (HMMs) and Gaussian mixture models (GMMs) similar to methods used in the speech recognition community for tasks such as speaker identification and clustering. Initial experiments using a Norwegian ortolan bunting (Emberiza hortulana) data set show the feasibility and effectiveness of the approach. Individually distinct acoustic features have been observed in a wide range of animal species, and this combined with the widespread success of speaker identification and verification methods for human speech suggests that robust automatic identification of individuals from their vocalizations is attainable. Only a few studies, however, have yet attempted to use individual acoustic distinctiveness to directly assess population density and structure. The approach introduced here offers a direct mechanism for using individual vocal variability to create simpler and more accurate population assessment tools in vocally active species.
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Affiliation(s)
- Kuntoro Adi
- Santa Dharma University, Mrican, Yogyakarta 55002, Indonesia
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Price CL, Johnson MT, Lindsay T, Dalton D, DeBaun MR. The Sickle Cell Sabbath: a community program increases first-time blood donors in the African American faith community. Transfusion 2009; 49:519-23. [DOI: 10.1111/j.1537-2995.2008.02009.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Guidroz JA, Johnson MT, Scott-Conner C, De Young B, Weigel RJ. The use of touch prep for the evaluation of sentinel lymph nodes in breast cancer. Cancer Res 2009. [DOI: 10.1158/0008-5472.sabcs-1018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Abstract #1018
Background: Sentinel lymph node (SLN) biopsy has become the standard of care for the evaluation of axillary metastasis in breast cancer. The accurate determination of metastasis in SLNs at the time of surgery is required in order to properly select those patients who should undergo axillary node dissection (AND).
 Methods: We performed a retrospective review of 402 breast cancer patients who underwent SLN biopsy with evaluation of 931 nodes by touch prep from June 2000 through January 2007. Results of touch prep diagnosis at the time of surgery were compared to final pathologic evaluation by permanent H&E. All false negative (FN) results were re-reviewed to determine possible reasons for errors in diagnosis.
 Results: At least one SLN was successfully identified in 379 patients. Of 68 patients with a true positive SLN, all underwent AND and in 46% the SLN was the only node in which metastases were identified. A total of 32 patients (8.44%) had at least one FN result. In 931 nodes evaluated, there were 38 (4.1%) FN results and no false positives. There were no significant differences between FN results in patients with invasive ductal cancer (26 of 284 patients, 4.3% nodes) compared to invasive lobular cancer (5 of 46 patients, 5.6% nodes). The remaining patients had DCIS or other primary diagnosis with two FN SLNs. Of the 38 SLNs with a FN result, 30 (79%) had only micromets on permanent H&E. Of the remaining 8 SLN with a FN touch prep, 3 of 703 SLNs (0.4%) occurred with invasive ductal cancer and 4 of 108 SLNs (3.7%) occurred with invasive lobular cancer, demonstrating a significant difference, p=0.01. In the 32 patients with a FN SLN result, 19 patients underwent completion AND and in 12 patients (63%), the SLNs were the only nodes with cancer. Examining the 19 patients with FN SLN who underwent completion AND, 14 patients had invasive ductal cancer with only 4 (29%) having cancer found in non-SLN compared to 5 patients with invasive lobular cancer with 3 (60%) having cancer in non-SLN. Touch prep evaluation of SLN in breast cancer had an overall sensitivity of 72%, specificity of 100%, positive predictive value of 100% and negative predictive value of 95.4%. The cost for touch prep is $32 less per node compared to frozen section or an average cost reduction of $74 per patient.
 Conclusion: The accuracy of touch prep for the evaluation of SLN in breast cancer compares favorably to the reported results for frozen section with a lower cost. In patients with a FN SLN result, the SLNs are likely to be the only nodes involved with metastases, especially if the SLN is found to have only micromets. However, patients with invasive lobular cancer were more likely to have a FN finding in the setting of marcomets and were more likely to have metastases in non-SLNs. Patients with invasive lobular cancer who have a negative SLN by touch prep should have the SLN evaluated by frozen section to confirm the diagnosis. The data also suggest that patients with invasive lobular cancer and a FN SLN by touch prep may benefit from AND.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1018.
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Affiliation(s)
- JA Guidroz
- 1 Surgery, University of Iowa, Iowa City, IA
| | - MT Johnson
- 1 Surgery, University of Iowa, Iowa City, IA
| | | | - B De Young
- 2 Pathology, University of Iowa, Iowa City, IA
| | - RJ Weigel
- 1 Surgery, University of Iowa, Iowa City, IA
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Abstract
A significant and often unavoidable problem in bioacoustic signal processing is the presence of background noise due to an adverse recording environment. This paper proposes a new bioacoustic signal enhancement technique which can be used on a wide range of species. The technique is based on a perceptually scaled wavelet packet decomposition using a species-specific Greenwood scale function. Spectral estimation techniques, similar to those used for human speech enhancement, are used for estimation of clean signal wavelet coefficients under an additive noise model. The new approach is compared to several other techniques, including basic bandpass filtering as well as classical speech enhancement methods such as spectral subtraction, Wiener filtering, and Ephraim-Malah filtering. Vocalizations recorded from several species are used for evaluation, including the ortolan bunting (Emberiza hortulana), rhesus monkey (Macaca mulatta), and humpback whale (Megaptera novaeanglia), with both additive white Gaussian noise and environment recording noise added across a range of signal-to-noise ratios (SNRs). Results, measured by both SNR and segmental SNR of the enhanced wave forms, indicate that the proposed method outperforms other approaches for a wide range of noise conditions.
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Affiliation(s)
- Yao Ren
- Speech and Signal Processing Laboratory, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin 53233-1881, USA.
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Tao J, Johnson MT, Osiejuk TS. Acoustic model adaptation for ortolan bunting (Emberiza hortulana L.) song-type classification. J Acoust Soc Am 2008; 123:1582-1590. [PMID: 18345846 DOI: 10.1121/1.2837487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Automatic systems for vocalization classification often require fairly large amounts of data on which to train models. However, animal vocalization data collection and transcription is a difficult and time-consuming task, so that it is expensive to create large data sets. One natural solution to this problem is the use of acoustic adaptation methods. Such methods, common in human speech recognition systems, create initial models trained on speaker independent data, then use small amounts of adaptation data to build individual-specific models. Since, as in human speech, individual vocal variability is a significant source of variation in bioacoustic data, acoustic model adaptation is naturally suited to classification in this domain as well. To demonstrate and evaluate the effectiveness of this approach, this paper presents the application of maximum likelihood linear regression adaptation to ortolan bunting (Emberiza hortulana L.) song-type classification. Classification accuracies for the adapted system are computed as a function of the amount of adaptation data and compared to caller-independent and caller-dependent systems. The experimental results indicate that given the same amount of data, supervised adaptation significantly outperforms both caller-independent and caller-dependent systems.
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Affiliation(s)
- Jidong Tao
- Speech and Signal Processing Laboratory, Marquette University, PO Box 1881, Milwaukee, Wisconsin 53233-1881, USA.
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19
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Abstract
A new feature extraction model, generalized perceptual linear prediction (gPLP), is developed to calculate a set of perceptually relevant features for digital signal analysis of animal vocalizations. The gPLP model is a generalized adaptation of the perceptual linear prediction model, popular in human speech processing, which incorporates perceptual information such as frequency warping and equal loudness normalization into the feature extraction process. Since such perceptual information is available for a number of animal species, this new approach integrates that information into a generalized model to extract perceptually relevant features for a particular species. To illustrate, qualitative and quantitative comparisons are made between the species-specific model, generalized perceptual linear prediction (gPLP), and the original PLP model using a set of vocalizations collected from captive African elephants (Loxodonta africana) and wild beluga whales (Delphinapterus leucas). The models that incorporate perceptional information outperform the original human-based models in both visualization and classification tasks.
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Affiliation(s)
- Patrick J Clemins
- Speech and Signal Processing Laboratory, Marquette University, P.O. Box 1881, Milwaukee, Wisconsin 53233-1881, USA.
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Clemins PJ, Johnson MT, Leong KM, Savage A. Automatic classification and speaker identification of African elephant (Loxodonta africana) vocalizations. J Acoust Soc Am 2005; 117:956-963. [PMID: 15759714 DOI: 10.1121/1.1847850] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A hidden Markov model (HMM) system is presented for automatically classifying African elephant vocalizations. The development of the system is motivated by successful models from human speech analysis and recognition. Classification features include frequency-shifted Mel-frequency cepstral coefficients (MFCCs) and log energy, spectrally motivated features which are commonly used in human speech processing. Experiments, including vocalization type classification and speaker identification, are performed on vocalizations collected from captive elephants in a naturalistic environment. The system classified vocalizations with accuracies of 94.3% and 82.5% for type classification and speaker identification classification experiments, respectively. Classification accuracy, statistical significance tests on the model parameters, and qualitative analysis support the effectiveness and robustness of this approach for vocalization analysis in nonhuman species.
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Affiliation(s)
- Patrick J Clemins
- Speech and Signal Processing Laboratory, Marquette University, Milwaukee, Wisconsin 53233-1881, USA.
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Moss SM, Johnson MT, Murray KEH, Trypuc JM, Alidina S. 53 Pediatric Pain: A Network's Approach to Education. Paediatr Child Health 2004. [DOI: 10.1093/pch/9.suppl_a.35a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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22
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Nindl G, Hughes EF, Johnson MT, Spandau DF, Vesper DN, Balcavage WX. Effect of ultraviolet B radiation and 100 Hz electromagnetic fields on proliferation and DNA synthesis of Jurkat cells. Bioelectromagnetics 2002; 23:455-63. [PMID: 12210564 DOI: 10.1002/bem.10039] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The use of ultraviolet B light (UVB) has been proven to be highly effective for treatment of various inflammatory skin diseases, but UVB phototherapy is limited by its carcinogenic side effects. It is necessary to uncover effectors that augment UVB so that similar or improved efficacy can be obtained with lower UVB doses. We found that low frequency, low intensity electromagnetic fields (EMFs) can act as such an effector and synergistically inhibit T lymphocyte proliferation. We first characterized the effects of UVB on Jurkat cells, a model for cutaneous T lymphocytes, and determined UVB's dose dependent inhibition of cell proliferation and induction of apoptosis. Cells exposed to a sublethal UVB dose retained their sensitivity to UVB, but repetitive irradiation seemed to cause accumulation of delayed DNA damage. We then exposed cells to combinations of UVB plus EMFs and found that 100 Hz, 1 mT EMFs decrease DNA synthesis of UVB-activated Jurkat cells by 34 +/- 13% compared to UVB alone. The decrease is, however, most effective when relatively high UVB doses are employed. Since EMFs alone had only a very weak inhibitory effect (10 +/- 2%), the data suggest that EMFs augment the cell killing effects of UVB in a synergistic way. These findings could provide the basis for development of new and improved clinical phototherapy protocols.
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Affiliation(s)
- G Nindl
- Center for Medical Education, Indiana University School of Medicine, Terre Haute, Indiana 47809, USA.
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Louda SM, Pemberton RW, Johnson MT, Follett PA. Nontarget effects--the Achilles' heel of biological control? Retrospective analyses to reduce risk associated with biocontrol introductions. Annu Rev Entomol 2002; 48:365-396. [PMID: 12208812 DOI: 10.1146/annurev.ento.48.060402.102800] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Controversy exists over ecological risks in classical biological control. We reviewed 10 projects with quantitative data on nontarget effects. Ten patterns emerged: (a) Relatives of the pest are most likely to be attacked; (b) host-specificity testing defines physiological host range, but not ecological range; (c) prediction of ecological consequences requires population data; (d) level of impact varied, often in relation to environmental conditions; (e) information on magnitude of nontarget impact is sparse; (f) attack on rare native species can accelerate their decline; (g) nontarget effects can be indirect; (h) agents disperse from agroecosystems; (i) whole assemblages of species can be perturbed; and (j) no evidence on adaptation is available in these cases. The review leads to six recommendations: Avoid using generalists or adventive species; expand host-specificity testing; incorporate more ecological information; consider ecological risk in target selection; prioritize agents; and pursue genetic data on adaptation. We conclude that retrospective analyses suggest clear ways to further increase future safety of biocontrol.
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Affiliation(s)
- S M Louda
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0118, USA.
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Johnson MT, Morrison S, Heeger S, Mooney S, Byers PH, Robin NH. A variant of osteogenesis imperfecta type IV with resolving kyphomelia is caused by a novel COL1A2 mutation. J Med Genet 2002; 39:128-32. [PMID: 11836364 PMCID: PMC1735034 DOI: 10.1136/jmg.39.2.128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
Recent single-unit recording studies have clarified how multiple parameters of movement are signaled by individual cortical and cerebellar neurons, and also that multiple coordinate frames are utilized. Cognitive processes also modulate the firing of these neurons. The various signals and coordinate systems vary in time and evolve throughout a behavioral sequence, consistent with the demands of the task and the required sensorimotor transformations.
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Affiliation(s)
- M T Johnson
- Department of Neuroscience, University of Minnesota, Lions Research Building, 2001 Sixth Street SE, Minneapolis, MN 55455, USA
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Johnson MT, Mahmood S, Hyatt SL, Yang HS, Soloway PD, Hanson RW, Patel MS. Inactivation of the murine pyruvate dehydrogenase (Pdha1) gene and its effect on early embryonic development. Mol Genet Metab 2001; 74:293-302. [PMID: 11708858 DOI: 10.1006/mgme.2001.3249] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A deficiency of pyruvate dehydrogenase complex (PDC) in humans results in lactic acidosis and neurological dysfunction that frequently results in death during infancy. Using gene targeting technology, a silent mutation was introduced into the murine X-linked Pdha1 gene that encodes the alpha subunit of the pyruvate dehydrogenase or E1 component of the complex. Two loxP sequences were introduced into intronic sequences flanking exon 8 to generate the Pdha1(flox8) allele. In vitro studies in embryonic stem cells demonstrated that deletion of exon 8 ablated PDC activity. Homozygous Pdha1(flox8) females were bred with male mice carrying a wild-type Pdha1 allele and a transgene that ubiquitously expresses the Cre recombinase to produce progeny with a deletion in exon 8, Pdha1(Deltaex8). The majority of progeny were found to be mosaic with the presence of both the flox and deleted alleles, and there were no apparent phenotypic effects associated with the null allele. The mosaic mice were interbred to increase the degree of mosaicism for the Pdha1(Deltaex8) allele in the subsequent generation, resulting in a significantly smaller litter size (54% reduction). Embryos carrying predominantly the Pdha1(Deltaex8) allele were found to be globally delayed in development by 9.5 days postcoitus, with resorption occurring over the following several days. These findings demonstrate an essential role for oxidative metabolism of glucose during the early postimplantation period of prenatal development.
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Affiliation(s)
- M T Johnson
- Department of Biochemistry, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY 14214, USA
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Pu CT, Johnson MT, Forman DE, Hausdorff JM, Roubenoff R, Foldvari M, Fielding RA, Singh MA. Randomized trial of progressive resistance training to counteract the myopathy of chronic heart failure. J Appl Physiol (1985) 2001; 90:2341-50. [PMID: 11356801 DOI: 10.1152/jappl.2001.90.6.2341] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic heart failure (CHF) is characterized by a skeletal muscle myopathy not optimally addressed by current treatment paradigms or aerobic exercise. Sixteen older women with CHF were compared with 80 age-matched peers without CHF and randomized to progressive resistance training or control stretching exercises for 10 wk. Women with CHF had significantly lower muscle strength (P < 0.0001) but comparable aerobic capacity to women without CHF. Exercise training was well tolerated and resulted in no changes in resting cardiac indexes in CHF patients. Strength improved by an average of 43.4 +/- 8.8% in resistance trainers vs. -1.7 +/- 2.8% in controls (P = 0.001), muscle endurance by 299 +/- 66% vs. 1 +/- 3% (P = 0.001), and 6-min walk distance by 49 +/- 14 m (13%) vs. -3 +/- 19 m (-3%) (P = 0.03). Increases in type I fiber area (9.5 +/- 16%) and citrate synthase activity (35 +/- 21%) in skeletal muscle were independently predictive of improved 6-min walk distance (r2 = 0.78; P = 0.0024). High-intensity progressive resistance training improves impaired skeletal muscle characteristics and overall exercise performance in older women with CHF. These gains are largely explained by skeletal muscle and not resting cardiac adaptations.
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Affiliation(s)
- C T Pu
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer United States Department of Agriculture, Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA
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Neu MP, Johnson MT, Matonic JH, Scott BL. Actinide interactions with microbial chelators: the dioxobis[pyridine-2,6-bis(monothiocarboxylato)]uranium(VI) ion. Acta Crystallogr C 2001; 57:240-2. [PMID: 11250561 DOI: 10.1107/s0108270100017285] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2000] [Accepted: 11/13/2000] [Indexed: 11/10/2022] Open
Abstract
The title complex, bis(tetraphenylphosphonium) dioxobis(pyridine-2,6-dicarbothioato-O,N,O')uranium(VI), (C(24)H(20)P)(2)[UO(2)(C(7)H(3)NO(2)S(2))(2)], was prepared by reacting two equivalents of pyridine-2,6-bis(monothiocarboxylate) (pdtc) with uranyl nitrate. The geometry of the eight-coordinate U atom is hexagonal bipyramidal, with the uranyl O atoms in apical positions. This is the first reported complex in which this ligand binds a metal through the O and not the S atoms. Principal bond lengths include uranyl lengths of 1.774 (2) A, U--O distances of 2.434 (2) and 2.447 (3) A, and two U--N distances of 2.647 (3) A. The anion lies on an inversion centre.
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Affiliation(s)
- M P Neu
- MS G739, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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Affiliation(s)
- M T Johnson
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Wetzel BJ, Nindl G, Vesper DN, Swez JA, Jasti AC, Johnson MT. Electromagnetic field effects: changes in protein phosphorylation in the Jurkat E6.1 cell line. Biomed Sci Instrum 2001; 37:203-8. [PMID: 11347389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
This study is aimed at expanding the role of electromagnetic field (EMF) therapy for treatment of inflammatory diseases and obtaining new information on the biophysical mechanism of action of weak EMFs. The mechanism of action of EMFs on biological systems is a question that has yet to be answered. Several models have been proposed to explain the coupling of low frequency fields to biological systems, although no consensus has been reached as to which most adequately portrays the true mechanism. Protein phosphorylation is a major cellular metabolic regulator. As such, it has the potential to be a valuable indicator of the impact of EMFs on cellular metabolism. Using a well-controlled EMF exposure system, we examined the regulatory role of EMFs on low molecular weight protein phosphorylation in Jurkat E6.1 cells, a transformed human leukemic T cell line. Jurkat cells were grown to mid-log phase, preloaded with 32P and exposed to EMF (0.1 mT, 60 Hz) or sham for 30 minutes. Cell proteins were separated by SDS-polyacrylamide gel electrophoresis and incorporated radioactivity of low molecular weight proteins (18-23 kDa) was quantified by AMBIS data analysis. Three of five experiments showed no difference in protein phosphorylation in EMF exposed samples compared to controls, while two experiments revealed an EMF effect. We identified stathmin, an important T cell signaling phosphoprotein, as one of the low molecular weight proteins present in our Jurkat cell system. Stathmin expression as well as its phosphorylation was decreased in samples that were exposed to EMFs compared to controls. These data indicate that phosphorylation of individual proteins might be masked by the presence of numerous other proteins in whole cell lysate experiments. Further studies testing other low molecular weight T cell signaling molecules may validate this hypothesis.
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Affiliation(s)
- B J Wetzel
- Terre Haute Center for Medical Education, Indiana University School of Medicine, Indiana State University, Terre Haute, IN 47809, USA
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Johnson MT, Vanscoy-Cornett A, Vesper DN, Swez JA, Chamberlain JK, Seaward MB, Nindl G. Electromagnetic fields used clinically to improve bone healing also impact lymphocyte proliferation in vitro. Biomed Sci Instrum 2001; 37:215-20. [PMID: 11347391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
An important aspect of medical device development is the need to understand how a device produces a specific biological effect. The focus can then be on optimizing that effect by device modification and repeated testing. Several reports from this lab have targeted programmed cell death, or apoptosis, as a cellular pathway that is induced by exposure of transformed leukemic T-cells in culture to specific frequency and intensity electromagnetic fields (EMFs). An EMF delivery device capable of selectively inducing T-cell apoptosis in human tissues could be used to enhance healing by limiting the production of molecules that promote inflammatory disorders such as psoriasis and tendonitis. In the present study, we examined the normal T-cell response to EMF exposure in vitro. In the peripheral blood, 70-80% of the lymphocytes are T-cells, and thus is a rich source of normal cells that match the transformed T-cells used in other experiments (Jurkat cells). We isolated lymphocytes from the peripheral blood of humans and rats, cultured them in nutritive medium and exposed them to either a complex 1.8 mT pulsed EMF (Electrobiology, Inc.), a 0.1 mT, 60 Hz power frequency EMF or a 0.2 mT, 100 Hz sinusoidal EMF. Control lymphocytes were cultured similarly, without field exposure. Lymphocytes were then treated with T-cell mitogens and evaluated for proliferative capacity after an additional 72 hours culture. Results indicate that T-cell proliferation is modulated by in vitro exposure to defined EMFs. The potential use of an EMF delivery device capable of selectively inducing such T-cell effects is discussed.
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Affiliation(s)
- M T Johnson
- Terre Haute Center for Medical Education, Indiana University School of Medicine, Terre Haute, IN 47809, USA
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Jasti AC, Wetzel BJ, Aviles H, Vesper DN, Nindl G, Johnson MT. Effect of a wound healing electromagnetic field on inflammatory cytokine gene expression in rats. Biomed Sci Instrum 2001; 37:209-14. [PMID: 11347390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
In earlier studies, we have shown that pulsed electromagnetic fields (PEMFs) induce programmed cell death in cultured T cells and that rats exposed in vivo to PEMFs have decreased T-cell proliferative capacity. These data led us to hypothesize that PEMFs might be used to control proliferation of inflammatory lymphocytes and therefore beneficially affect inflammatory diseases. Tendinitis is characterized by painful inflammation of the tendon. Inflammation is characterized by massive infiltration of T lymphocytes, neutrophils and macrophages into the damaged tissue. These inflammatory cells produce a variety of cytokines, which are the cellular regulators of inflammation. The current study tests whether in vivo PEMF effects are mediated via systemic cytokine production in rat tendinitis. Inflammation was chemically induced in female Harlan Sprague Dawley rats Achilles' tendons and a wound healing PEMF (Electrobiology, Inc.) was applied for 4 hours immediately following injury. Spleens from control and experimental animals were harvested 24 hours later and total RNA was extracted from the tissues. Gene expression was analyzed by reverse transcription of mRNA, and polymerase chain reaction amplification (RT-PCR) using primers specific for the cytokines IFN-gamma, IL-1 beta, IL-6, TNF-alpha, and TGF-beta, as well as for the control beta-actin. RT-PCR products were separated on 1.5% agarose gels and band intensities were normalized to beta-actin gene expression of the same sample. TGF-beta was the only cytokine produced at high levels in rats with tendinitis in comparison to the other cytokines. PEMFs did not show an effect on any cytokine expression in the spleens, 24 hours after induction of tendinitis. Further studies need to test if cumulative exposures of PEMFs are able to regulate inflammatory cytokine expression either at the site of inflammation or at the local lymph nodes.
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Affiliation(s)
- A C Jasti
- Terre Haute Center for Medical Education, Indiana University School of Medicine, Indiana State University, Terre Haute, IN 47809, USA
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Vesper DN, Nindl G, Johnson MT, Spandau DF, Swez JA, Balcavage WX. A system for simultaneous ultraviolet light and electromagnetic field exposure in in vitro experiments. Biomed Sci Instrum 2001; 37:221-6. [PMID: 11347392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Ultraviolet light (UV) is a common treatment for skin diseases such as psoriasis, but bears the risk of carcinogenic side effects. We have biological evidence that electromagnetic fields (EMFs) can act additively with UV so that new therapeutic protocols combining UV and EMF might be developed to improve psoriasis phototherapy. In this study we report on a system that allows in vitro experiments testing this hypothesis. For simultaneous exposure of cell cultures to UVB and EMF, we built Merritt coils with an integrated UV exposure system. The coils can be operated in a sham or experimental mode (up to 1.5 mT and 20,000 Hz). Two UV bulbs were fitted inside the coils for UVB doses between 100-1000 J/m2/nm. In the exposure area the EMF is uniform within 0.0038%. For exposure, the cells are cultured in standard culture plates and placed in a specifically designed box. The box holds two plates in a top chamber covered with a Saran Wrap lid (91% UV transmission) so that cells are exposed to UVB and EMFs. The bottom chamber holds two plates, where cells are screened from UVB and only exposed to EMFs. Temperature control is maintained (+/- 1 degree C) by airflow vents on the side of the box and a fan placed 25 cm away from the cell culture box. To maintain sterility within the box the vents are covered with a bacterial filter. The box lid has additional ventilation through two air direction changes to create an additional bacterial barrier similar to that in culture plate lids.
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Affiliation(s)
- D N Vesper
- Indiana State University, Department of Physics, Terre Haute, IN 47809, USA
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Abstract
Velocity is an important determinant of the simple spike discharge of cerebellar Purkinje cells. In a previous study, Purkinje cells in the intermediate and lateral cerebellum recorded during manual tracking were found to be tuned to a combination of direction and speed, (i.e. preferred velocity). In this study a population analysis of this simple spike discharge was used to determine whether the velocity of tracking could be predicted. For the majority (30/32) of direction-speed combinations, the population response accurately specified the target velocity. A temporal analysis showed how the population response gradually converged to the required velocity 200 ms prior to the onset of tracking. Therefore, the simple spike discharge of a Purkinje cell ensemble contains sufficient information to reconstruct target velocity, providing support for the hypothesis that the cerebellum controls or signals movement velocity.
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Affiliation(s)
- J D Coltz
- Department of Neuroscience, University of Minnesota, Lions Research Building, Minneapolis, MN 55455, USA
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Johnson MT, Starnberg HI, Hughes HP. Magnetic interactions in core level photo-emission and photo-electron diffraction from NaCrS2. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/20/27/016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
The cerebellum and motor cortices are hypothesized to make fundamentally different but synergistic contributions to the control of movement. Richly interconnected, these structures must communicate and translate salient parameters of movement. This review examines the similarities and differences in the encoding of multiple limb movement parameters in the cerebellum and motor cortices. Also presented are recent data on direction and speed coding by cerebellar Purkinje cells and primary motor and dorsal premotor cortical neurons during a visually-instructed, manual tracking task. Both similarities and differences have been found in the way that these two motor areas process movement parameters. For example, the two motor control structures encode direction with almost identical depths of modulation, which may simplify the exchange of directional signals. Two major differences between the cerebellum and motor cortices consist of the distribution of the preferred directions and the manner in which direction and speed are jointly signaled within the discharge of individual neurons. First, an anterior-posterior distribution of preferred directions has been shown for both reaching and manual tracking, consistent with an intrinsic reference frame and/or the structure of afferent input. In contrast, neurons in the motor cortices have uniformly distributed preferred directions, consistent with general purpose directional calculations. Secondly, Purkinje cells in the cerebellum and motor cortices combine movement direction and speed information differently. For example, Purkinje cell discharge encodes combinations of direction and speed, a 'preferred velocity', while the motor cortical neurons use a temporal parcellation scheme to encode multiple parameters of movement. These results demonstrate that the cerebellum and motor cortices process and use kinematic information in fundamentally different ways that may underlie the functional uniqueness of the two motor control structures.
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Affiliation(s)
- M T Johnson
- Department of Neuroscience, University of Minnesota, Lions Research Building, 2001 Sixth Street SE, 55455, Minneapolis, MN, USA.
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Abstract
Synthons Tl1[TCNE]*- (1) and Tl12[TCNE]2- (2), for [TCNE]*- and [TCNE]2-, respectively, in metathesis reactions have been quantitatively prepared and characterized. The structure of 1 was solved and refined in a monoclinic unit cell at 27 degrees C [C2/c, a = 12.6966 (12) angstroms, b=7.7599 (7) angstroms, c=15.5041 (15) angstroms, beta = 96.610 (5) degrees , V= 1517.4 (2) angstroms3, Dcalcd = 2.911 gcm-3, Z=8, R1 = 0.0575, omegaR2=0.0701] and exhibits nuCN absorptions at 2,191 (s) and 2,162 (s) cm-1 consistent with metal-bound [TCNE]*-. The structure of 1 consists of a distorted square antiprismatic octacoordinate Tl1 bound to six monodentate [TCNE]*-s with TlN separations ranging from 2.901 to 3.171 angstroms averaging 3.020 angstroms, and one bidentate [TCNE]*- with TlN separations averaging 3.279 angstroms. The TlN bonding is attributed to electrostatic bonding. The [TCNE]*-s form dimerized zigzag chains with intra- and interdimer separations of 2.87 and 3.29 angstroms, respectively. The tight pi-[TCNE](2)2- dimer is diamagnetic and has the shortest intradimer [TCNE]*- distance reported. These synthons for [TCNE]*- and [TCNE]2- in metathesis reactions lead to the precipitation of, for example, TlIX (X = Cl, Br, OAc). Reaction of 1 with MnIII(porphyrin)X (X = Cl, OAc) forms the molecule-based magnets of [MnIII(porphyrin)][TCNE] composition, while the reaction of [CrI(C6H6)2]Br and (Me2N)2CC(NMe2)2Cl2, [TDAE]Cl2, with 1 forms [CrI(C6H6)2] [TCNE] and [TDAE][TCNE]2, respectively. The structure of [TDAE][TCNE]2.MeCN was solved and refined in an orthorhombic unit cell at 21 degrees C [I222, a = 10.2332(15), b = 13.341(6), c = 19.907(8) angstroms, V= 2717.7 angstroms3, Z = 4; Dcalcd = 1.216 gcm-3, R=0.083, Romega = 0.104] and exhibits upsilonCN absorptions at 2,193 (m), 2,174 (s), and 2,163 (s) cm-1 consistent with isolated [TCNE](2)2- , in contrast to the aforementioned TlI bound [TCNE](2)2-. The reaction of 2 with [TDAE]Cl2 forms [TDAE]2+[TCNE]2-.
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Affiliation(s)
- MT Johnson
- Department of Chemistry, University of Utah, Salt Lake City 84112-0850, USA
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Holschneider CH, Felix JC, Satmary W, Johnson MT, Sandweiss LM, Montz FJ. A single-visit cervical carcinoma prevention program offered at an inner city church: A pilot project. Cancer 1999; 86:2659-67. [PMID: 10594861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
BACKGROUND A single-visit cervical carcinoma prevention program was implemented, integrating screening, diagnosis, treatment, and health education in the familiar environment of the community church. METHODS Nonpregnant women age 18 years or older, who had not received cervical carcinoma screening in the preceding year were eligible. Subjects provided information on personal demographics, health, and knowledge regarding cervical carcinoma prevention. Thereafter, cervical cytology was collected, processed, and interpreted on site. Participants attended small-group instruction on cervical carcinoma prevention. Screening results were given to each subject individually. Patients with abnormal cytology underwent immediate colposcopy with biopsies or loop electrosurgical excision procedure as indicated. Participant satisfaction and educational impact were evaluated. RESULTS Ninety of the 98 participants reported that Spanish was their native language; 59 did not speak English. Fifty-four had had fewer than 6 years of education and 55 were unemployed. Seventy-eight did not have a regular physician or health insurance. Twenty-four either had never undergone cervical carcinoma screening or had let more than 5 years elapse since their previous examination. None of nine potential barriers assessed correlated with past compliance with cervical carcinoma screening. The mean time for processing and on-site interpretation of cervical cytology smears was 22.6 +/- 5.3 minutes. The median time patients spent in the program was 75 minutes. There was a significant improvement in the subjects' knowledge regarding cervical carcinoma prevention. All participants were highly satisfied. CONCLUSIONS This parish-based, integrated, single-visit program for the prevention of cervical carcinoma was easily implemented and provided care to a substantial proportion of underserved patients.
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Affiliation(s)
- C H Holschneider
- Department of Gynecology and Obstetrics, School of Medicine, University of California-Los Angeles, Los Angeles, California 90095-740, USA
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Johnson MT, Coltz JD, Ebner TJ. Encoding of target direction and speed during visual instruction and arm tracking in dorsal premotor and primary motor cortical neurons. Eur J Neurosci 1999; 11:4433-45. [PMID: 10594670 DOI: 10.1046/j.1460-9568.1999.00846.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The encoding of direction and speed in the discharge of dorsal premotor (PMd) and primary motor (MI) neurons was studied during two-dimensional visually-instructed pursuit arm movements in which eight directions and four constant speeds were independently manipulated. Each trial consisted of equal durations of visual observation of target movement without hand movement (cue) and visual pursuit-tracking of the target with the hand (track). A total of 240 neurons was recorded from PMd and MI in two Macaca mulatta monkeys. Two classes of regression analyses were used to relate neuronal firing during the cue and track periods to direction and speed. First, the average firing from each period was fitted to target direction or speed. Period-averaged firing significantly correlated with direction more frequently in the track than in the cue period. Conversely, correlations with speed (with or without direction) were more common in the cue than in the track period. Secondly, a binwise regression evaluated the temporal evolution of firing correlations with direction and speed. Supporting the period-based results, significant binwise correlations of the discharge with speed occurred preferentially during the cue period when there was no hand movement. Prior to movement, correlations of the firing with direction became significant and continued through the movement. Both analyses demonstrated a distinct tendency for neurons to be modulated by speed information early and by direction information later. This temporal parcellation reflects both the sequential demands of the task and constraints placed on the neural computations. The early representation of target speed is hypothesized to reflect the need to calculate a 'go signal' for the initiation of movement.
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Affiliation(s)
- M T Johnson
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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Surprenant AM, Hura SL, Harper MP, Jamieson LH, Long G, Thede SM, Rout A, Hsueh TH, Hockema SA, Johnson MT, Srinivasan PN, White CM, Laflen JB. Familiarity and pronounceability of nouns and names. Behav Res Methods Instrum Comput 1999; 31:638-49. [PMID: 10633979 DOI: 10.3758/bf03200740] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ratings of familiarity and pronounceability were obtained from a random sample of 199 surnames (selected from over 80,000 entries in the Purdue University phone book) and 199 nouns (from the Kucera-Francis, 1967, word database). The distributions of ratings for nouns versus names are substantially different: Nouns were rated as more familiar and easier to pronounce than surnames. Frequency and familiarity were more closely related in the proper name pool than the word pool, although both correlations were modest. Ratings of familiarity and pronounceability were highly related for both groups. A production experiment showed that rated pronounceability was highly related to the time taken to produce a name. These data confirm the common belief that there are differences in the statistical and distributional properties of words as compared to proper names. The value of using frequency and the ratings of familiarity and pronounceability for predicting variations in actual pronunciations of words and names are discussed.
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Affiliation(s)
- A M Surprenant
- Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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Coltz JD, Johnson MT, Ebner TJ. Cerebellar Purkinje cell simple spike discharge encodes movement velocity in primates during visuomotor arm tracking. J Neurosci 1999; 19:1782-803. [PMID: 10024363 PMCID: PMC6782164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
Pathophysiological, lesion, and electrophysiological studies suggest that the cerebellar cortex is important for controlling the direction and speed of movement. The relationship of cerebellar Purkinje cell discharge to the control of arm movement parameters, however, remains unclear. The goal of this study was to examine how movement direction and speed and their interaction-velocity-modulate Purkinje cell simple spike discharge in an arm movement task in which direction and speed were independently controlled. The simple spike discharge of 154 Purkinje cells was recorded in two monkeys during the performance of two visuomotor tasks that required the animals to track targets that moved in one of eight directions and at one of four speeds. Single-parameter regression analyses revealed that a large proportion of cells had discharge modulation related to movement direction and speed. Most cells with significant directional tuning, however, were modulated at one speed, and most cells with speed-related discharge were modulated along one direction; this suggested that the patterns of simple spike discharge were not adequately described by single-parameter models. Therefore, a regression surface was fitted to the data, which showed that the discharge could be tuned to specific direction-speed combinations (preferred velocities). The overall variability in simple spike discharge was well described by the surface model, and the velocities corresponding to maximal and minimal discharge rates were distributed uniformly throughout the workspace. Simple spike discharge therefore appears to integrate information about both the direction and speed of arm movements, thereby encoding movement velocity.
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Affiliation(s)
- J D Coltz
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis Minnesota 55455, USA
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Johnson MT, Coltz JD, Hagen MC, Ebner TJ. Visuomotor processing as reflected in the directional discharge of premotor and primary motor cortex neurons. J Neurophysiol 1999; 81:875-94. [PMID: 10036299 DOI: 10.1152/jn.1999.81.2.875] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Premotor and primary motor cortical neuronal firing was studied in two monkeys during an instructed delay, pursuit tracking task. The task included a premovement "cue period," during which the target was presented at the periphery of the workspace and moved to the center of the workspace along one of eight directions at one of four constant speeds. The "track period" consisted of a visually guided, error-constrained arm movement during which the animal tracked the target as it moved from the central start box along a line to the opposite periphery of the workspace. Behaviorally, the animals tracked the required directions and speeds with highly constrained trajectories. The eye movements consisted of saccades to the target at the onset of the cue period, followed by smooth pursuit intermingled with saccades throughout the cue and track periods. Initially, an analysis of variance (ANOVA) was used to test for direction and period effects in the firing. Subsequently, a linear regression analysis was used to fit the average firing from the cue and track periods to a cosine model. Directional tuning as determined by a significant fit to the cosine model was a prominent feature of the discharge during both the cue and track periods. However, the directional tuning of the firing of a single cell was not always constant across the cue and track periods. Approximately one-half of the neurons had differences in their preferred directions (PDs) of >45 degrees between cue and track periods. The PD in the cue or track period was not dependent on the target speed. A second linear regression analysis based on calculation of the preferred direction in 20-ms bins (i.e., the PD trajectory) was used to examine on a finer time scale the temporal evolution of this change in directional tuning. The PD trajectories in the cue period were not straight but instead rotated over the workspace to align with the track period PD. Both clockwise and counterclockwise rotations occurred. The PD trajectories were relatively straight during most of the track period. The rotation and eventual convergence of the PD trajectories in the cue period to the preferred direction of the track period may reflect the transformation of visual information into motor commands. The widely dispersed PD trajectories in the cue period would allow targets to be detected over a wide spatial aperture. The convergence of the PD trajectories occurring at the cue-track transition may serve as a "Go" signal to move that was not explicitly supplied by the paradigm. Furthermore, the rotation and convergence of the PD trajectories may provide a mechanism for nonstandard mapping. Standard mapping refers to a sensorimotor transformation in which the stimulus is the object of the reach. Nonstandard mapping is the mapping of an arbitrary stimulus into an arbitrary movement. The shifts in the PD may allow relevant visual information from any direction to be transformed into an appropriate movement direction, providing a neural substrate for nonstandard stimulus-response mappings.
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Affiliation(s)
- M T Johnson
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Abstract
Studies of Fc-mediated phagocytosis by mouse macrophages identified a contractile activity at the distal margins of forming phagosomes. Time-lapse video microscopic analysis of macrophages containing rhodamine-labeled actin and fluorescein dextran showed that actin was concentrated at the distal margins of closing phagosomes. Phagocytosis-related contractile activities were observed when one IgG-opsonized erythrocyte was engaged by two macrophages. Both cells extended pseudopodia until they met midway around the erythrocyte. It was then constricted and pulled into two phagosomes, which remained interconnected by a string of erythrocyte membrane. Butanedione monoxime, an uncompetitive inhibitor of class II and perhaps other myosins, and wortmannin and LY294002, inhibitors of phosphoinositide 3-kinase, prevented the constrictions without inhibiting the initial pseudopod extension. Immunofluorescence microscopy showed the presence of myosins IC, II, V and IXb in phagosomes. Of these, only myosin IC was concentrated around the strings connecting shared erythrocytes, suggesting that myosin IC mediates the purse-string-like contraction that closes phagosomes. The sequential processes of pseudopod extension and contraction can explain how macropinosomes and spacious phagosomes form without guidance from a particle surface.
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Affiliation(s)
- J A Swanson
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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Abstract
This study examined the directional modulation of dorsal premotor (PMd) cells as a function of time in an instructed delay, reaching task that systematically varied direction and accuracy constraints. In two monkeys, the activity of 150 PMd cells was recorded and the preferred direction (PD) of the firing as a function of time, the PD trajectory, was calculated. Forty-one cells had nearly continuous significant directional tuning of at least 1 s duration (mean duration 1694 +/- 754 ms) that began in the instructed delay period and continued into the movement period. The PD gradually changed in time (mean change of 47.7 +/- 40.8 degrees), a change best described as a rotation. The change in the directional tuning as a function of time is consistent with the hypothesis that the PMd plays a role in the non-standard mapping of sensory stimuli into motor commands.
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Affiliation(s)
- C R Mason
- Department of Neurosurgery, University of Minnesota, Minneapolis 55455, USA
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Johnson MT, Carter CB. Thin-Film Reaction between [alpha]-Fe2O3 and (001) MgO. Microsc Microanal 1998; 4:141-145. [PMID: 23232183 DOI: 10.1017/s1431927698980138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/1998] [Accepted: 04/02/1998] [Indexed: 06/01/2023]
Abstract
The kinetics of a thin-film, solid-state reaction were investigated in the spinel-forming oxide system Fe2O3/MgO. In this study, epitactic thin films of Fe2O3 (α, or corundum, structure) were deposited on (001)-oriented MgO using pulsed-laser deposition (PLD). The resulting diffusion couples were then reacted at elevated temperatures in air to induce the reaction between the thin-film and bulk substrate to form the spinel, MgFe2O4. Both the as-deposited and reacted diffusion couples were characterized using low-voltage scanning and transmission electron microscopy. These techniques allow the kinetics of the reaction and the structural properties of the spinel to be investigated.
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Affiliation(s)
- M T Johnson
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, 204 Amundson Hall, Minneapolis, MN 55455
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Johnson MT, Yang HS, Magnuson T, Patel MS. Targeted disruption of the murine dihydrolipoamide dehydrogenase gene (Dld) results in perigastrulation lethality. Proc Natl Acad Sci U S A 1997; 94:14512-7. [PMID: 9405644 PMCID: PMC25038 DOI: 10.1073/pnas.94.26.14512] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Dld gene product, known as dihydrolipoamide dehydrogenase or the E3 component, catalyzes the oxidation of dihydrolipoyl moieties of four mitochondrial multienzyme complexes: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched-chain alpha-ketoacid dehydrogenase, and the glycine cleavage system. Deficiency of E3 activity in humans results in various degrees of neurological dysfunction and organic acidosis caused by accumulation of branched-chain amino acids and lactic acid. In this study, we have introduced a null mutation into the murine Dld gene (Dldtm1mjp). The heterozygous animals are shown to have approximately half of wild-type activity levels for E3 and all affected multienzyme complexes but are phenotypically normal. In contrast, the Dld-/- class dies prenatally with apparent developmental delay at 7.5 days postcoitum followed by resorption by 9.5 days postcoitum. The Dld-/- embryos cease to develop at a time shortly after implantation into the uterine wall when most of the embryos have begun to gastrulate. This null phenotype provides in vivo evidence for the requirement of a mitochondrial oxidative pathway during the perigastrulation period. Furthermore, the early prenatal lethal condition of the complete deficiency state may explain the low incidence of detectable cases of E3 deficiency in humans.
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Affiliation(s)
- M T Johnson
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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