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Hoffman HM, Mueller JL, Broide DH, Wanderer AA, Kolodner RD. Mutation of a new gene encoding a putative pyrin-like protein causes familial cold autoinflammatory syndrome and Muckle-Wells syndrome. Nat Genet 2001; 29:301-5. [PMID: 11687797 PMCID: PMC4322000 DOI: 10.1038/ng756] [Citation(s) in RCA: 1200] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Familial cold autoinflammatory syndrome (FCAS, MIM 120100), commonly known as familial cold urticaria (FCU), is an autosomal-dominant systemic inflammatory disease characterized by intermittent episodes of rash, arthralgia, fever and conjunctivitis after generalized exposure to cold. FCAS was previously mapped to a 10-cM region on chromosome 1q44 (refs. 5,6). Muckle-Wells syndrome (MWS; MIM 191900), which also maps to chromosome 1q44, is an autosomal-dominant periodic fever syndrome with a similar phenotype except that symptoms are not precipitated by cold exposure and that sensorineural hearing loss is frequently also present. To identify the genes for FCAS and MWS, we screened exons in the 1q44 region for mutations by direct sequencing of genomic DNA from affected individuals and controls. This resulted in the identification of four distinct mutations in a gene that segregated with the disorder in three families with FCAS and one family with MWS. This gene, called CIAS1, is expressed in peripheral blood leukocytes and encodes a protein with a pyrin domain, a nucleotide-binding site (NBS, NACHT subfamily) domain and a leucine-rich repeat (LRR) motif region, suggesting a role in the regulation of inflammation and apoptosis.
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Hovis WA, Clark DK, Anderson F, Austin RW, Wilson WH, Baker ET, Ball D, Gordon HR, Mueller JL, El-Sayed SZ, Sturm B, Wrigley RC, Yentsch CS. Nimbus-7 Coastal Zone Color Scanner: System Description and Initial Imagery. Science 1980; 210:60-3. [PMID: 17751151 DOI: 10.1126/science.210.4465.60] [Citation(s) in RCA: 279] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Coastal Zone Color Scanner (CZCS) on Nimbus-7, launched in October 1978, is the only sensor in orbit that is specifically designed to study living marine resources. The initial imagery confirms that CZCS data can be processed to a level that reveals subtle variations in the concentration of phytoplankton pigments. This development has potential applications for the study of large-scale patchiness in phytoplankton distributions, the evolution of spring blooms, water mass boundaries, and mesoscale circulation patterns.
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Gordon HR, Clark DK, Mueller JL, Hovis WA. Phytoplankton Pigments from the Nimbus-7 Coastal Zone Color Scanner: Comparisons with Surface Measurements. Science 1980; 210:63-6. [PMID: 17751152 DOI: 10.1126/science.210.4465.63] [Citation(s) in RCA: 266] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The removal of atmospheric effects from Nimbus-7 Coastal Zone Color Scanner (CZCS) images reveals eddy-like ocean turbidity patterns not apparent in the original calibrated images. Comparisons of the phytoplankton pigment concentrations derived from the corrected CZCS radiances with surface measurements agree to within less than 0.5 log C, where C is the sum of the concentrations of chlorophyll a plus phaeopigments a (in milligrams per cubic meter).
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Mueller JL, Ravi Ram K, McGraw LA, Bloch Qazi MC, Siggia ED, Clark AG, Aquadro CF, Wolfner MF. Cross-species comparison of Drosophila male accessory gland protein genes. Genetics 2005; 171:131-43. [PMID: 15944345 PMCID: PMC1456506 DOI: 10.1534/genetics.105.043844] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Accepted: 05/19/2005] [Indexed: 12/23/2022] Open
Abstract
Drosophila melanogaster males transfer seminal fluid proteins along with sperm during mating. Among these proteins, ACPs (Accessory gland proteins) from the male's accessory gland induce behavioral, physiological, and life span reduction in mated females and mediate sperm storage and utilization. A previous evolutionary EST screen in D. simulans identified partial cDNAs for 57 new candidate ACPs. Here we report the annotation and confirmation of the corresponding Acp genes in D. melanogaster. Of 57 new candidate Acp genes previously reported in D. melanogaster, 34 conform to our more stringent criteria for encoding putative male accessory gland extracellular proteins, thus bringing the total number of ACPs identified to 52 (34 plus 18 previously identified). This comprehensive set of Acp genes allows us to dissect the patterns of evolutionary change in a suite of proteins from a single male-specific reproductive tissue. We used sequence-based analysis to examine codon bias, gene duplications, and levels of divergence (via dN/dS values and ortholog detection) of the 52 D. melanogaster ACPs in D. simulans, D. yakuba, and D. pseudoobscura. We show that 58% of the 52 D. melanogaster Acp genes are detectable in D. pseudoobscura. Sequence comparisons of ACPs shared and not shared between D. melanogaster and D. pseudoobscura show that there are separate classes undergoing distinctly dissimilar evolutionary dynamics.
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Comparative Study |
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Mueller JL, Isaacson D, Newell JC. A reconstruction algorithm for electrical impedance tomography data collected on rectangular electrode arrays. IEEE Trans Biomed Eng 1999; 46:1379-86. [PMID: 10582423 DOI: 10.1109/10.797998] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A three-dimensional reconstruction algorithm in electrical impedance imaging is presented for determining the conductivity distribution beneath the surface of a medium, given surface voltage data measured on a rectangular array of electrodes. Such an electrode configuration may be desirable for using electrical impedence tomography to detect tumors in the human breast. The algorithm is based on linearizing the conductivity about a constant value. Here, we describe a simple implementation of the algorithm on a four-electrode--by-four-electrode array and the reconstructions obtained from numerical and experimental tank data. The results demonstrate significantly better spatial resolution in the plane of the electrodes than with respect to depth.
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Isaacson D, Mueller JL, Newell JC, Siltanen S. Imaging cardiac activity by the D-bar method for electrical impedance tomography. Physiol Meas 2006; 27:S43-50. [PMID: 16636419 PMCID: PMC1752230 DOI: 10.1088/0967-3334/27/5/s04] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A practical D-bar algorithm for reconstructing conductivity changes from EIT data taken on electrodes in a 2D geometry is described. The algorithm is based on the global uniqueness proof of Nachman (1996 Ann. Math. 143 71-96) for the 2D inverse conductivity problem. Results are shown for reconstructions from data collected on electrodes placed around the circumference of a human chest to reconstruct a 2D cross-section of the torso. The images show changes in conductivity during a cardiac cycle.
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Evaluation Study |
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Anderson JP, Mueller JL, Misaghi A, Anderson S, Sivagnanam M, Kolodner RD, Hoffman HM. Initial description of the human NLRP3 promoter. Genes Immun 2008; 9:721-6. [PMID: 18719602 PMCID: PMC4477692 DOI: 10.1038/gene.2008.66] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 07/24/2008] [Accepted: 07/24/2008] [Indexed: 01/06/2023]
Abstract
Mutations in NLRP3 (CIAS1) are identified in a continuum of related inflammatory disorders, known as cryopyrinopathies since NLRP3 codes for the protein cryopyrin. Approximately 40% of patients with classic presentation lack mutations in the coding region of NLRP3 suggesting heterogeneity or epigenetic factors. Cryopyrin is a key regulator of proinflammatory cytokine release. Therefore, variations in the NLRP3 promoter sequence may have effects on disease state in patients with cryopyrinopathies and other inflammatory diseases. In this report, we confirmed three 5'-untranslated region splice forms with two separate transcriptional start sites, and identified potential promoter regions and six new DNA promoter variants. One variant is unique to a mutation negative cryopyrinopathy patient and increases in vitro gene expression. Additional studies can now be performed to further characterize the NLRP3 promoter and sequence variants, which will lead to better understanding of the regulation of NLRP3 expression and its role in disease.
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research-article |
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Mueller JL, Isaacson D, Newell JC. Reconstruction of conductivity changes due to ventilation and perfusion from EIT data collected on a rectangular electrode array. Physiol Meas 2001; 22:97-106. [PMID: 11236896 DOI: 10.1088/0967-3334/22/1/313] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper we demonstrate that conductivity changes caused by ventilation and perfusion in a human subject can be reconstructed from electrical impedance tomography data collected on a rectangular array of electrodes placed on a subject's chest. Currents are applied on the electrodes and the resulting voltages on the electrodes are measured. A 3D reconstruction algorithm is used to reconstruct the conductivity distribution in the region beneath the array. Time traces of the reconstructed conductivity distribution demonstrate the detected changes in conductivity due to ventilation and perfusion.
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Lee ZP, Carder KL, Peacock TG, Davis CO, Mueller JL. Method to derive ocean absorption coefficients from remote-sensing reflectance. APPLIED OPTICS 1996; 35:453-462. [PMID: 21069030 DOI: 10.1364/ao.35.000453] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A method to derive in-water absorption coefficients from total remote-sensing reflectance (ratio of the upwelling radiance to the downwelling irradiance above the surface) analytically is presented. For measurements made in the Gulf of Mexico and Monterey Bay, with concentrations of chlorophyll-a ranging from 0.07 to 50 mg/m(3), comparisons are made for the total absorption coefficients derived with the suggested method and those derived with diffuse attenuation coefficients. For these coastal to open-ocean waters, including regions of upwelling and the Loop Current, the results are as follows: at 440 nm the difference between the two methods is 13.0% (r(2) = 0.96) for total absorption coefficients ranging from 0.02 to 2.0 m(-1); at 488 nm the difference is 14.5% (r(2) = 0.97); and at 550 nm the difference is 13.6% (r(2) = 0.96). The results indicate that the method presented works very well for retrieval of in-water absorption coefficients exclusively from remotely measured signals, and that this method has a wide range of potential applications in oceanic remote sensing.
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Hara S, Kuhns ER, Ellenberger EA, Mueller JL, Shibuya T, Endo T, Quock RM. Involvement of nitric oxide in intracerebroventricular beta-endorphin-induced neuronal release of methionine-enkephalin. Brain Res 1995; 675:190-4. [PMID: 7796128 DOI: 10.1016/0006-8993(95)00065-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Previous work has suggested that the antinociceptive effect of nitrous oxide (N2O) in rats is mediated, at least in part, by beta-endorphin (beta-EP) and that centrally administered beta-EP stimulates release of methionine-enkephalin (ME) in the rat spinal cord. Since inhibition of central nitric oxide (NO) production has been found to suppress N2O antinociception, we examined the possible involvement of NO in the release of spinal cord ME by i.c.v. beta-EP. Urethane-anesthetized, male Sprague-Dawley rats were intrathecally (i.t.) perfused with artificial cerebrospinal fluid (aCSF) and fractions of perfusate were assayed for immunoreactive (i.r.) ME. The beta-EP-induced increase in ME concentration in the i.t. perfusate was significantly suppressed by perfusing the animal with aCSF containing 100 microM L-NG-nitro arginine (L-NOARG), an inhibitor of NO synthase (NOS). The further addition of 50 microM L-arginine (L-ARG), but not D-arginine (D-ARG), to the aCSF reversed the suppression of the ME change by L-NOARG. However, the potency of L-ARG decreased with increasing concentrations of L-ARG. On the other hand, increasing the concentration of L-NOARG in the aCSF to 250 microM failed to produce a greater suppression of the beta-EP-induced increase in ME. These findings suggest that NO may mediate the beta-EP-induced release of ME in the spinal cord and that interference with this mechanism might be an explanation for the antagonism of N2O antinociception in rats by NOS inhibitors.
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11
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DeAngelo M, Mueller JL. 2D D-bar reconstructions of human chest and tank data using an improved approximation to the scattering transform. Physiol Meas 2010; 31:221-32. [DOI: 10.1088/0967-3334/31/2/008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27 |
12
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Cahill FJ, Ellenberger EA, Mueller JL, Tseng LF, Quock RM. Antagonism of nitrous oxide antinociception in mice by intrathecally administered antisera to endogenous opioid peptides. J Biomed Sci 2000; 7:299-303. [PMID: 10895052 DOI: 10.1007/bf02253248] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Previously it was demonstrated that nitrous oxide antinociception in the mouse abdominal constriction test is mediated by kappa-opioid receptors. Since nitrous oxide is thought to cause the neuronal release of endogenous opioid peptide to stimulate opioid receptors, this study was designed to identify the opioid peptides involved, especially in the spinal cord, by determining whether nitrous oxide antinociception can be differentially inhibited by intrathecally (i. t.) administered antisera to different opioid peptides. Male NIH Swiss mice were pretreated i.t. with rabbit antisera to opioid peptides then exposed 24 h later to one of three different concentrations of nitrous oxide in oxygen. Dose-response curves constructed from the data indicated that the antinociceptive effect of nitrous oxide was significantly antagonized by antisera to various dynorphins (DYNs) and methionine-enkephalin (ME), but not by antiserum to beta-endorphin (beta-EP). The AD(50) values for nitrous oxide antinociception were significantly elevated by antisera to DYNs and ME but not beta-EP. These findings of this study support the hypothesis that nitrous oxide antinociception in the mouse abdominal constriction test involves the neuronal release of DYN and ME in the spinal cord.
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MESH Headings
- Analgesics, Non-Narcotic/antagonists & inhibitors
- Analgesics, Non-Narcotic/pharmacology
- Analgesics, Opioid/antagonists & inhibitors
- Analgesics, Opioid/immunology
- Analgesics, Opioid/metabolism
- Animals
- Dose-Response Relationship, Drug
- Dynorphins/antagonists & inhibitors
- Dynorphins/immunology
- Dynorphins/metabolism
- Enkephalin, Methionine/antagonists & inhibitors
- Enkephalin, Methionine/immunology
- Enkephalin, Methionine/metabolism
- Immune Sera/administration & dosage
- Immune Sera/immunology
- Immune Sera/pharmacology
- Injections, Spinal
- Male
- Mice
- Nitrous Oxide/antagonists & inhibitors
- Nitrous Oxide/pharmacology
- Opioid Peptides/antagonists & inhibitors
- Opioid Peptides/immunology
- Opioid Peptides/metabolism
- Pain/metabolism
- Pain/physiopathology
- Pain Measurement
- Peptide Fragments/antagonists & inhibitors
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Spinal Cord/physiopathology
- beta-Endorphin/antagonists & inhibitors
- beta-Endorphin/immunology
- beta-Endorphin/metabolism
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Mueller JL, Lam CT, Dahl D, Asiedu MN, Krieger MS, Bellido-Fuentes Y, Kellish M, Peters J, Erkanli A, Ortiz EJ, Muasher LC, Taylor PT, Schmitt JW, Venegas G, Ramanujam N. Portable Pocket colposcopy performs comparably to standard-of-care clinical colposcopy using acetic acid and Lugol's iodine as contrast mediators: an investigational study in Peru. BJOG 2018; 125:1321-1329. [PMID: 29893472 DOI: 10.1111/1471-0528.15326] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Our goal was to develop a tele-colposcopy platform for primary-care clinics to improve screening sensitivity and access. Specifically, we developed a low-cost, portable Pocket colposcope and evaluated its performance in a tertiary healthcare centre in Peru. DESIGN AND SETTING Images of the cervix were captured with a standard-of-care and Pocket colposcope at la Liga Contra el Cáncer in Lima, Peru. POPULATION Two hundred Peruvian women with abnormal cytology and/or human papillomavirus positivity were enrolled. METHODS Images were collected using acetic acid and Lugol's iodine as contrast agents. Biopsies were taken as per standard-of-care procedures. MAIN OUTCOME MEASURES After passing quality review, images from 129 women were sent to four physicians who provided a diagnosis for each image. RESULTS Physician interpretation of images from the two colposcopes agreed 83.1% of the time. The average sensitivity and specificity of physician interpretation compared with pathology was similar for the Pocket (sensitivity = 71.2%, specificity = 57.5%) and standard-of-care (sensitivity = 79.8%, specificity = 56.6%) colposcopes. When compared with a previous study where only acetic acid was applied to the cervix, results indicated that adding Lugol's iodine as a secondary contrast agent improved the percent agreement between colposcopes for all pathological categories by up to 8.9% and the sensitivity and specificity of physician interpretation compared with pathology by over 6.0 and 9.0%, respectively. CONCLUSIONS The Pocket colposcope performance was similar to that of a standard-of-care colposcope when used to identify precancerous and cancerous lesions using acetic acid and Lugol's iodine during colposcopy examinations in Peru. TWEETABLE ABSTRACT The Pocket colposcope performance was similar to that of a standard-of-care colposcope when identifying cervical lesions.
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Journal Article |
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Quock RM, Mueller JL, Vaughn LK. Strain-dependent differences in responsiveness of mice to nitrous oxide (N2O) antinociception. Brain Res 1993; 614:52-6. [PMID: 8348330 DOI: 10.1016/0006-8993(93)91017-m] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
N2O antinociception was assessed in eight inbred and two outbred mouse strains. Results indicated the following order of responsiveness among the 10 strains: A/J (most sensitive), C57BL/6ByJ, C57BL/6J, BALB/cByJ, C3H/HeJ, Swiss-Webster, CXBK/ByJ, ICR, CBA/J and DBA/2J (least sensitive). These results demonstrate significant strain-dependent differences in antinociceptive responsiveness to N2O. The weak antinociceptive response to N2O in the DBA/2J strain, which is sensitive to morphine and U-50, 488H, indicates some underlying neurobiological difference in the DBA/2J mouse that imparts resistance to N2O. The responsiveness of CXBK/ByJ mice to N2O indicates that mu-opioid receptors may not play an important role in N2O antinociception in mice.
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MESH Headings
- 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer
- Analgesics/pharmacology
- Animals
- Dose-Response Relationship, Drug
- Male
- Mice
- Mice, Inbred A
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Inbred DBA
- Mice, Inbred Strains
- Morphine/pharmacology
- Nitrous Oxide/pharmacology
- Pain Measurement/drug effects
- Pyrrolidines/pharmacology
- Species Specificity
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Comparative Study |
32 |
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Mueller JL. Nimbus-7 CZCS: electronic overshoot due to cloud reflectance. APPLIED OPTICS 1988; 27:438-440. [PMID: 20523613 DOI: 10.1364/ao.27.000438] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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37 |
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16
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Quock RM, Mueller JL, Vaughn LK, Belknap JK. Nitrous oxide antinociception in BXD recombinant inbred mouse strains and identification of quantitative trait loci. Brain Res 1996; 725:23-9. [PMID: 8828582 DOI: 10.1016/0006-8993(96)00211-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Among inbred mouse strains, DBA/2 mice are unique because of their poor responsiveness to nitrous oxide (N2O) antinociception. As a first step towards identifying candidate genes involved in determining antinociceptive responsiveness to N2O, male mice from the DBA/2 strain, the more responsive C57BL/6 strain, their B6D2F1 offspring, and 22 BXD recombinant inbred (RI) strains derived from DBA/2 and C57BL/6 mice were exposed to N2O and evaluated using the acetic acid abdominal constriction test. When exposed to 70% N2O, C57BL/6, DBA/2 and B6D2F1 mice exhibited antinociceptive responses of 78, 22 and 55%, respectively. The BXD RI strains demonstrated varying degrees of responsiveness to N2O. Cluster analysis revealed one cluster of 16 strains approximating the C57BL/6 progenitor (61.9-100% antinociceptive response to 70% N2O) and another of six strains around the DBA/2 progenitor (9.1-40% antinociceptive response to 70% N2O). The robust strain differences permitted screening the strain means with 1492 marker loci previously mapped in BXD RI strains. Using a QTL analysis specifically tailored to existing mouse RI strains, we found associations at the 0.01 level on seven chromosomes with the most promising marker loci being Il2ra, Hbb, Hmg1rs7 and Gsl5 on chromosomes 2, 7, 16 and 19, respectively (P < 0.002).
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Murphy EK, Mueller JL, Newell JC. Reconstructions of conductive and insulating targets using the D-bar method on an elliptical domain. Physiol Meas 2007; 28:S101-14. [PMID: 17664628 PMCID: PMC2464779 DOI: 10.1088/0967-3334/28/7/s08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The D-bar algorithm based on A Nachman's 2D global uniqueness proof for the inverse conductivity problem (Nachman 1996 Ann. Math. 143 71-96) is implemented on an elliptical domain. The scattering transform is computed on an ellipse and the complete electrode model (CEM) for the forward problem is computed with the finite element method (FEM) in order to obtain static conductivity reconstructions of conductive and insulating targets in a saline-filled tank. It is demonstrated that the spatial artifacts in the image are significantly reduced when the domain is properly modeled in the reconstruction, as opposed to being modeled as a disk.
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Research Support, U.S. Gov't, Non-P.H.S. |
18 |
18 |
18
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Hamilton SJ, Mueller JL, Alsaker M. Incorporating a Spatial Prior into Nonlinear D-Bar EIT Imaging for Complex Admittivities. IEEE TRANSACTIONS ON MEDICAL IMAGING 2017; 36:457-466. [PMID: 28114061 PMCID: PMC5384275 DOI: 10.1109/tmi.2016.2613511] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Electrical Impedance Tomography (EIT) aims to recover the internal conductivity and permittivity distributions of a body from electrical measurements taken on electrodes on the surface of the body. The reconstruction task is a severely ill-posed nonlinear inverse problem that is highly sensitive to measurement noise and modeling errors. Regularized D-bar methods have shown great promise in producing noise-robust algorithms by employing a low-pass filtering of nonlinear (nonphysical) Fourier transform data specific to the EIT problem. Including prior data with the approximate locations of major organ boundaries in the scattering transform provides a means of extending the radius of the low-pass filter to include higher frequency components in the reconstruction, in particular, features that are known with high confidence. This information is additionally included in the system of D-bar equations with an independent regularization parameter from that of the extended scattering transform. In this paper, this approach is used in the 2-D D-bar method for admittivity (conductivity as well as permittivity) EIT imaging. Noise-robust reconstructions are presented for simulated EIT data on chest-shaped phantoms with a simulated pneumothorax and pleural effusion. No assumption of the pathology is used in the construction of the prior, yet the method still produces significant enhancements of the underlying pathology (pneumothorax or pleural effusion) even in the presence of strong noise.
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research-article |
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Abstract
The terms assistive technology and universal design challenge designers, engineers, and technologists to consider the broadest possible use for the things they create, to make assistive technology as useful to nondisabled persons as to those with disabilities, and to make the products and environments we design as usable as possible for everyone, regardless of age or ability.
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Mueller JL, Quock RM. Contrasting influences of 5-hydroxytryptamine receptors in nitrous oxide antinociception in mice. Pharmacol Biochem Behav 1992; 41:429-32. [PMID: 1533464 DOI: 10.1016/0091-3057(92)90122-v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
5-Hydroxytryptamine (5-HT) mechanisms may play a role in opioid-mediated antinociception. Since opioid mechanisms have been implicated in nitrous oxide antinociception, this study was conducted to determine the possible role of 5-HT receptors in nitrous oxide antinociception. Male Swiss Webster mice were pretreated with one of two 5-HT receptor blockers and then tested in the acetic acid abdominal constriction test for their antinociceptive response to nitrous oxide, the kappa-opioid agonist U-50,488H, or the mu-opioid agonist sufentanil. Results indicate that the 5-HT3 receptor blocker ICS-205,930 antagonized both nitrous oxide and U-50,488H effects but not that of sufentanil. Mianserin, a 5-HT1c/5-HT2 receptor blocker, effects but not that of sufentanil. Mianserin, a 5-HT1c/5-HT2 receptor blocker, potentiated effects of both nitrous oxide and U-50,488H but not that of sufentanil. These findings show similarities in nitrous oxide and U-50,488H antinociception and further support our hypothesis that nitrous oxide works through central kappa-opioid mechanisms in mice. The results also suggest different roles for 5-HT receptor subtypes in mediating or modulating the antinociceptive effect of nitrous oxide.
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Comparative Study |
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Mueller JL, Siltanen S. The D-bar method for electrical impedance tomography-demystified. INVERSE PROBLEMS 2020; 36:093001. [PMID: 33380765 PMCID: PMC7771826 DOI: 10.1088/1361-6420/aba2f5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Electrical impedance tomography (EIT) is an imaging modality where a patient or object is probed using harmless electric currents. The currents are fed through electrodes placed on the surface of the target, and the data consists of voltages measured at the electrodes resulting from a linearly independent set of current injection patterns. EIT aims to recover the internal distribution of electrical conductivity inside the target. The inverse problem underlying the EIT image formation task is nonlinear and severely ill-posed, and hence sensitive to modeling errors and measurement noise. Therefore, the inversion process needs to be regularized. However, traditional variational regularization methods, based on optimization, often suffer from local minima because of nonlinearity. This is what makes regularized direct (non-iterative) methods attractive for EIT. The most developed direct EIT algorithm is the D-bar method, based on Complex Geometric Optics solutions and a nonlinear Fourier transform. Variants and recent developments of D-bar methods are reviewed, and their practical numerical implementation is explained.
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Hamilton SJ, Mueller JL, Santos TR. Robust computation in 2D absolute EIT (a-EIT) using D-bar methods with the 'exp' approximation. Physiol Meas 2018; 39:064005. [PMID: 29846182 DOI: 10.1088/1361-6579/aac8b1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Absolute images have important applications in medical electrical impedance tomography (EIT) imaging, but the traditional minimization and statistical based computations are very sensitive to modeling errors and noise. In this paper, it is demonstrated that D-bar reconstruction methods for absolute EIT are robust to such errors. APPROACH The effects of errors in domain shape and electrode placement on absolute images computed with 2D D-bar reconstruction algorithms are studied on experimental data. MAIN RESULTS It is demonstrated with tank data from several EIT systems that these methods are quite robust to such modeling errors, and furthermore the artefacts arising from such modeling errors are similar to those occurring in classic time-difference EIT imaging. SIGNIFICANCE This study is promising for clinical applications where absolute EIT images are desirable but previously thought impossible.
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Hamilton SJ, Herrera CNL, Mueller JL, Von Herrmann A. A direct D-bar reconstruction algorithm for recovering a complex conductivity in 2-D. INVERSE PROBLEMS 2012; 28:095005. [PMID: 23641121 PMCID: PMC3638890 DOI: 10.1088/0266-5611/28/9/095005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A direct reconstruction algorithm for complex conductivities in W2,∞ (Ω), where Ω is a bounded, simply connected Lipschitz domain in ℝ2, is presented. The framework is based on the uniqueness proof by Francini [Inverse Problems 20 2000], but equations relating the Dirichlet-to-Neumann to the scattering transform and the exponentially growing solutions are not present in that work, and are derived here. The algorithm constitutes the first D-bar method for the reconstruction of conductivities and permittivities in two dimensions. Reconstructions of numerically simulated chest phantoms with discontinuities at the organ boundaries are included.
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Mueller JL. Ocean color spectra measured off the Oregon coast: characteristic vectors. APPLIED OPTICS 1976; 15:394-402. [PMID: 20164980 DOI: 10.1364/ao.15.000394] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The ocean color spectrum is defined as the ratio of the spectrum of light upwelled from the sea to the spectrum of light incident on the sea surface. Ocean color spectra, observed from an airplane flown over waters off Oregon, are analyzed. The original spectra are resolved into fifty-five wavelength bands, each 5 nm wide. The shapes of these spectra are parametrized by, and shown to be accurately recoverable from, their first four principal components Y(i)(i = 1, 2, 3, 4). These Y(i) are the scalar projections of each spectrum on the first four characteristic vectors of the sample covariance matrix. Empirically determined characteristic vectors like these, but derived from a much larger and more globally representative sample of color spectra, may someday provide an efficient, standard basis for parameterizing ocean color spectra. Regression equations are found with which phytoplankton pigment concentration and water transparency may be estimated as linear functions of the parameters Y(i). Pigment concentration estimates thus obtained are imprecise. The poor fit is at least partly due to the inappropriateness of the linear regression model and the neglect of other optically important substances typically present in sea water.
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Mueller JL, Ellenberger EA, Vaughn LK, Belknap JK, Quock RM. Detection and mapping of quantitative trait loci that determine responsiveness of mice to nitrous oxide antinociception. Neuroscience 2004; 123:743-9. [PMID: 14706786 DOI: 10.1016/j.neuroscience.2003.10.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Exposure to 70% N(2)O evokes a robust antinociceptive effect in C57BL/6 (B6) but not in DBA/2 (D2) inbred mice. This study was conducted to identify quantitative trait loci (QTL) in the mouse genome that might determine responsiveness to N(2)O. Offspring from the F(2) generation bred from B6 and D2 progenitors exhibited a broad range of responsiveness to N(2)O antinociception as determined by the acetic acid-induced abdominal constriction test. QTL analysis was then used to dissect this continuous trait distribution into component loci, and to map them to broad chromosomal regions. To this end, 24 spleens were collected from each of the following four groups: male and female F(2) mice responding to 70% N(2)O in oxygen with 100% response (high-responders); and male and female F(2) mice responding with 0% response (low-responders). Genomic DNA was extracted from the spleens and genotyped with simple sequence length polymorphism MapPairs markers. Findings were combined with findings from the earlier QTL analysis from BXD recombinant inbred mice [Brain Res 725 (1996) 23]. Combined results revealed two significant QTL that influence responsiveness to nitrous oxide on proximal chromosome 2 and distal chromosome 5, and one suggestive QTL on midchromosome 18. The chromosome 2 QTL was evident only in males. A significant interaction was found between a locus on chromosome 6 and another on chromosome 13 with a substantial effect on N(2)O antinociception.
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Research Support, U.S. Gov't, P.H.S. |
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