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Johnson TK, Holm CE, Godshall SD. Ambulatory surgery: next-generation strategies for physicians and hospitals. HEALTHCARE FINANCIAL MANAGEMENT : JOURNAL OF THE HEALTHCARE FINANCIAL MANAGEMENT ASSOCIATION 2000; 54:48-51. [PMID: 11067006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Physicians' interest in investing and practicing in independent ambulatory surgery centers (ASCs) has grown. In the face of physician involvement in ASC development, healthcare organizations must contend with possible loss of surgical volume and revenues as well as decreased physician support and loyalty to the organization. Healthcare organizations can encourage physicians to remain in the organization by addressing physicians' concerns about the financial prospects and efficiency of independent and hospital-based ambulatory surgical arenas.
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Johnson TK, Schweppe RE, Septer J, Lewis RE. Phosphorylation of B-Myb regulates its transactivation potential and DNA binding. J Biol Chem 1999; 274:36741-9. [PMID: 10593981 DOI: 10.1074/jbc.274.51.36741] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription factor B-Myb is a cell cycle-regulated phosphoprotein and a potent regulator of cell cycle progression. Previous studies demonstrated that B-Myb was phosphorylated at the onset of S phase, suggesting that it could be due to cyclin-dependent kinases. We identified 10 B-Myb phosphorylation sites by automated peptide radiosequencing of tryptic phosphopeptides derived from in vivo (32)P-labeled B-Myb. Each B-Myb phosphorylation site contained a phosphoserine or phosphothreonine followed by a proline, suggesting that this phosphorylation is due to a proline-directed kinase. Cyclin A-Cdk2 and cyclin E-Cdk2 complexes each phosphorylated B-Myb in a cell-free system on the same sites as in intact cells. Furthermore, the ability of B-Myb to activate a reporter plasmid was enhanced by the cotransfection of cyclin A, whereas mutagenesis of the 10 identified phosphorylation sites from B-Myb blocked the effect of cyclin A coexpression. Additional analysis revealed that the effect of phosphorylation on B-Myb transactivation potential was enhanced by phosphorylation sites in its carboxyl-terminal half. One phosphorylation site (Ser(581)) appeared to negatively regulate DNA binding, as mutation of this site enhanced the ability of B-Myb to bind a Myb-binding sequence. These data suggest that B-Myb is a target for phosphorylation by cyclin-Cdk2 and that phosphorylation of B-Myb regulates its transcriptional activity.
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Johnson TK, Barnhart T. An alternative to Monte Carlo in determining release criteria for patients administered radioactive material. HEALTH PHYSICS 1999; 77:724-727. [PMID: 10568553 DOI: 10.1097/00004032-199912000-00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Barnes GT, Johnson TK. Medical physics graduate programs should focus on education and research and leave clinical training to residencies. Med Phys 1999; 26:2051-3. [PMID: 10535621 DOI: 10.1118/1.598785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Johnson TK, McClure D, McCourt S. MABDOSE. I: Characterization of a general purpose dose estimation code. Med Phys 1999; 26:1389-95. [PMID: 10435543 DOI: 10.1118/1.598636] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The MABDOSE software represents a general tool to perform internal radiation dosimetry. It uses a three-dimensional lattice in which to conduct radiation transport, scoring energy deposition in discrete voxels. The dosimetry system currently relies on the same algorithm used by the MIRD committee for photon transport, and assumes local deposition of particulate energy. A mathematical description of the dosimetry system's implementation is given. Additionally, a characterization of the system with respect to memory requirements, data libraries used, and simulation timing benchmarks, is presented. Validation of the software is presented in a companion manuscript.
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Johnson TK, McClure D, McCourt S. MABDOSE. II: Validation of a general purpose dose estimation code. Med Phys 1999; 26:1396-403. [PMID: 10435544 DOI: 10.1118/1.598637] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
UNLABELLED The MABDOSE software represents a general tool to assess internal radiation dose. A suite of tests are described that validate the dosimetry system's implementation. METHODS The validation suite is divided among tests that verify target digitalization, tumor digitalization and organ replacement, cumulated activity calculation, random number generation, radiation transport, and dose calculation. RESULTS A comparison between Reference Man organ volumes and MABDOSE organ volumes at (5 mm)3 resolution demonstrates volume correspondence within 10% save for ten organs having dimensions smaller than the target lattice resolution. An accounting of normal organ volume replaced by an arbitrary tumor volume indicates mass is conserved. A comparison between cumulated activities generated by MABDOSE and solutions obtained analytically demonstrates exact correspondence for curve-fitting algorithms. For mathematical modeling algorithms, cumulated activity solutions converge to their correct values provided sufficient data of high precision are input, accompanied by reasonable initial estimates of rate constants. A comparison of MABDOSE results with the MIRD 3 report demonstrates good agreement (<8% difference) in absorbed fractions for spheres at energies from 20 keV to 2.75 MeV. A comparison of MABDOSE results with the Cristy-Eckerman report demonstrates marginal agreement (specific absorbed fractions within a factor of 2 for all Reference Man organs) at simulation energies of 20, 50, and 100 keV. Lack of exact correspondence is attributed to volume digitalization errors, and to differences in cross-section libraries, interpolation schemes between cross-section data points, and random number generators. Finally, the doses reported by MABDOSE correspond to the correct algebraic combination of paired cumulated activities and "S" values. CONCLUSIONS The MABDOSE program has been validated as a general purpose computation tool for use in internal radionuclide dosimetry.
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Koss JE, Newman FD, Johnson TK, Kirch DL. Abdominal organ segmentation using texture transforms and a Hopfield neural network. IEEE TRANSACTIONS ON MEDICAL IMAGING 1999; 18:640-648. [PMID: 10504097 DOI: 10.1109/42.790463] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Abdominal organ segmentation is highly desirable but difficult, due to large differences between patients and to overlapping grey-scale values of the various tissue types. The first step in automating this process is to cluster together the pixels within each organ or tissue type. We propose to form images based on second-order statistical texture transforms (Haralick transforms) of a CT or MRI scan. The original scan plus the suite of texture transforms are then input into a Hopfield neural network (HNN). The network is constructed to solve an optimization problem, where the best solution is the minima of a Lyapunov energy function. On a sample abdominal CT scan, this process successfully clustered 79-100% of the pixels of seven abdominal organs. It is envisioned that this is the first step to automate segmentation. Active contouring (e.g., SNAKE's) or a back-propagation neural network can then be used to assign names to the clusters and fill in the incorrectly clustered pixels.
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Johnson TK, Nelson C, Kirch DL. A new method for the correction of gamma camera nonuniformity due to spatial distortion. Phys Med Biol 1996; 41:2179-88. [PMID: 8912389 DOI: 10.1088/0031-9155/41/10/023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A methodology for correcting scintillation camera nonuniformity resulting from spatial linearity distortion is described. The method simultaneously corrects for both variations in count density and distortions in spatial linearity without altering the intrinsic sensitivity or resolution of the imaging system. This approach to linearity correction requires only a single flood image from which the spatial shift vectors are derived. The algorithm has been implemented on a PC-based, EISA bus microcomputer, and reduces the measurement of integral uniformity for 201Tl from 25% to 5%. Combined with regional correction for photopeak pulse-heights shifts (i.e. energy correction), the algorithm represents a novel technique for implementing uniformity correction completely within software.
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Johnson TK, Stabin M. 111In-DTPA cisternography to investigate a possible cerebrospinal fluid (CSF) leak. J Nucl Med 1995; 36:1723-4. [PMID: 7658238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Johnson TK, Colby SB. Photon contribution to tumor dose from considerations of 131I radiolabeled antibody uptake in liver, spleen, and whole body. Med Phys 1993; 20:1667-74. [PMID: 8309439 DOI: 10.1118/1.596953] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The contribution of penetrating photon energy to tumor dose is usually ignored because of the difficulty in calculating absorbed fractions and because it is frequently assumed to represent a small proportion of the total energy. The MABDOSE software--written explicitly to simulate photon transport for the calculation of penetrating radiation absorbed fractions--was used to simulate the 131I photon spectrum originating from the liver, spleen, and whole body source organs. Specific absorbed fractions were calculated for tumors of radius 1.0, 1.5, and 2.0 cm placed near the liver and spleen in the Reference Man geometry. Cumulated activities were estimated using values reported from the literature. Dosimetry estimates from the combined cumulated activity and specific absorbed fractions indicate that neglecting the photon contribution underestimates the tumor dose by 10%-25%.
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Meredith RF, Johnson TK, Plott G, Macey DJ, Vessella RL, Wilson LA, Breitz HB, Williams LE. Dosimetry of solid tumors. Med Phys 1993; 20:583-92. [PMID: 8492767 DOI: 10.1118/1.597053] [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: 01/31/2023] Open
Abstract
Dosimetry data arising from a decade of radioimmunotherapy are summarized along with techniques utilized to arrive at the reported dose estimates. Generality of the MIRD methodology allows it to serve as a vehicle for the calculation of solid tumor dosimetry although several limitations exist. Nonstandard geometries of solid tumors will ultimately necessitate determination of absorbed fractions for the individual tumors. Several approaches currently under investigation are described. For reasons of practicality, solid tumor dosimetry estimates continue to use the assumption of homogeneous activity distribution in a source organ, accounting for either all radiation or only nonpenetrating radiation. As computation tools become available for incorporating inhomogeneous cellular level data, the currently used "average dose" as an index of tumor sterilization will likely be replaced with a statistical distribution based on the number of viable cells in the tumor volume. Estimates of a tumor control dose would be based upon a linear extension of dose coupled with a threshold dose for cell sterilization.
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Abstract
For radiation dosimetry calculations of radiolabeled monoclonal antibodies, (MAB), pharmacokinetics are critical. Specifically, pharmacokinetic modeling is a useful component of estimation of cumulated activity in various source organs in the body. It is thus important to formulate general methods of pharmacokinetic modeling and of pharmacokinetic data reduction, leading to cumulated activities. In this paper different types of models are characterized as "empirical," "analytical," and "compartmental" pharmacokinetic models. There remains a pressing need for quantitative studies in man for a proper understanding of the pharmacokinetics of MAb. Pharmacokinetic modeling of radiolabeled MAb in vivo has relied on relatively limited studies in man and complementary detailed measurements in animals. In either case, any model chosen for analysis of such data is inevitably based on measurements of limited accuracy and precision as well as assumptions regarding human physiology. Very few macroscopic compartmental pharmacokinetic models for MAb, have been tested over a range of conditions to determine their predictive ability. Extracorporeal immunoadsorption represents one approach for drastically altering the biokinetics of antibody distribution, and may serve to validate a given pharmacokinetic model. In addition to macroscopic modeling, the microscopic evaluation of the time-dependent distribution of radiolabeled MAb in tissues is of utmost importance for a proper understanding of the kinetics and radiobiologic effect. Many tumors do not exhibit homogeneous uptake. A mathematical understanding of that distribution is thus essential for accurate tumor dosimetry estimates. This review summarizes methodologies for pharmacokinetic modeling, critically reviews specific pharmacokinetic models and demonstrates the capability of modeling for predictive calculations of altered pharmacokinetics, emphasizing its use in dosimetric calculations.
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Johnson TK, Gonzalez R, Kasliwal RK, Lear JL, Feyerabend AJ, Dienhart DG, Ceriani RL, Bunn PA. Distribution of a breast-directed I-131-radiolabeled monoclonal antibody in blood and bone marrow: implications for radiation immunotherapy. Radiology 1992; 182:107-14. [PMID: 1727271 DOI: 10.1148/radiology.182.1.1727271] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Bone marrow is most often the dose-limiting organ in radiation immunotherapy. Controversy exists over optimal methods of estimating radiation dose to bone marrow. The authors compared findings in serial blood samples to findings in bone marrow biopsy samples as measures of bone marrow activity from which to calculate bone marrow dose. Peripheral blood samples and bone marrow biopsy samples were obtained from 11 female patients at 48 and 168 hours after infusion of iodine-131-labeled Mc5 antibody. Bone marrow biopsy data demonstrated markedly decreased specific activity compared with that measured in the peripheral blood. Activities at 48 hours after infusion ranged from 3% to 22% of the peripheral blood activity. These results indicate that activity concentration in the bone marrow is not equivalent to activity concentration in the blood for the Mc5 antibody. These results imply that a dose three to four times that indicated from serial blood samples could be tolerated by patients, provided the antibody-radioisotope does not bind to the marrow.
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Watson KL, Johnson TK, Denell RE. Lethal(1) aberrant immune response mutations leading to melanotic tumor formation in Drosophila melanogaster. DEVELOPMENTAL GENETICS 1991; 12:173-87. [PMID: 1907895 DOI: 10.1002/dvg.1020120302] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using P element-mediated mutagenesis we have isolated 20 X-linked lethal mutations, representing at least 14 complementation groups, which exhibit melanotic tumor phenotypes. We present the systematic analysis of this interesting group of lethal mutations that were selected for their visible melanotic or immune response. The lethal and melanotic tumor phenotypes of each lethal(1) aberrant immune response (air) mutation are pleiotropic effects of single genetic lesions. Lethality occurs throughout the larval and early pupal periods of development and larval development is extended in some air mutants. The air mutant lethal syndromes include abnormalities associated with the brain, haematopoietic organs, gut, salivary glands, ring glands, and imaginal discs. Additional characterization of the melanotic tumor mutations Tuml and tu(1)Szts have indicated that the melanotic tumor phenotype is similar to that observed in the air mutants. These studies have led to the proposal that two distinct classes of melanotic tumor mutations exist. Class 1 includes mutants in which melanotic tumors result from "autoimmune responses" or the response of an apparently normal immune system to the presence of abnormal target tissues. The Class 2 mutants display obvious defects in the haematopoietic organs or haemocytes, manifested as overgrowth, and the resulting aberrant immune system behavior may contribute to melanotic tumor formation.
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Hartmann C, Bloedow DC, Dienhart DG, Kasliwal R, Johnson TK, Gonzalez R, Bunn PA. A pharmacokinetic model describing the removal of circulating radiolabeled antibody by extracorporeal immunoadsorption. JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS 1991; 19:385-403. [PMID: 1920086 DOI: 10.1007/bf01061663] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Extracorporeal immunoadsorption is a new technique for removal of circulating radiolabeled antibody from the peripheral blood (1) to reduce background activity for improved tumor imaging, and (2) to reduce whole-body and marrow toxicity when high doses of radiolabeled antibodies are used for antitumor therapy. A pharmacokinetic model was developed to describe plasma disappearance of 111In-KC-4G3 prior to, during, and after immunoadsorption in humans. The model is developed based on a two-compartment open model, and during immunoadsorption a third compartment is added for removed radioactivity by the immunoadsorption column. Goodness-of-fit statistics indicate a good fit of the model to the data. The resulting pharmacokinetic parameters for a selected patient are V1 = 2.64 L, VSS = 3.64 L, t 1/2 alpha = 3.77 hr, and t 1/2 beta = 48.5 hr. The immunoadsorption clearance (CLIA = 19.3 ml/min) was 21-fold greater than the patient's plasma clearance (CL10 = 0.899 ml/min), indicating a very effective immunoadsorption process. The model predicts an increase in plasma radioactivity upon termination of immunoadsorption, probably due to redistribution of radioactivity from the extravascular compartment to the plasma in response to the rapid decline in plasma radioactivity during immunoadsorption. Two series of simulations were performed to examine the influence of onset time and duration of immunoadsorption. In series one the onset time was varied and in series two immunoadsorption duration was varied. In series one, the predicted radioactivity amounts adsorbed by the immunoadsorption column ranged from 75% of the injected dose (4-hr onset) to 52% of the injected dose (24-hr onset). In series two, immunoadsorbed radioactivity ranged from 32% (2-hr duration) to 64% of the injected dose (12-hr duration). When instituted as early as 4 hr, the predictions suggest that earlier immunoadsorption onset improves the effectiveness of radioactivity removal, relating to higher early circulation concentrations, and longer immunoadsorption periods remove more radioactivity, but also result in larger predicted radioactivity redistribution form tissue to plasma. To employ the immunoadsorption procedure for tumor imaging and therapy optimally, the data and our predictions indicate that a compromise must be made that will balance immunoadsorption onset and duration against tumor radioactivity uptake and subsequent radioactivity redistribution from tissues back to plasma. Together with biologic considerations providing sufficient antigen-antibody interaction and dependent on the utilized radioisotope, these data support the utility of extracorporeal immunoadsorption during the radioimmunodetection of cancer and for future therapeutic applications.
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Lear JL, Kasliwal RK, Feyerabend AJ, Pratt JP, Bunn PA, Dienhart DG, Gonzalez R, Johnson TK, Bloedow DC, Maddock SW. Improved tumor imaging with radiolabeled monoclonal antibodies by plasma clearance of unbound antibody with anti-antibody column. Radiology 1991; 179:509-12. [PMID: 1849662 DOI: 10.1148/radiology.179.2.1849662] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Imaging of tumors by using radiolabeled monoclonal antibodies (MoAs) is hindered by the presence of background activity. To reduce this problem, the authors investigated the process of removing labeled MoAs from plasma at selected times by means of extracorporeal immunoadsorption. In seven patients with either lung or breast carcinoma, an indium-111-labeled murine antibody was intravenously administered. Six to 24 hours later, immunoadsorption was performed by passing the patients' plasma through a goat anti-mouse antibody column connected to a plasma separator. Whole-body computer images were obtained before and after the treatment. Blood pool activity in the images was reduced by an average of 59%, while tumor activity dropped by only 10%. Tumor-to-blood activity ratios therefore more than doubled, improving by an average of 121% between the pre- and posttreatment image sets. Eight of 12 areas of known disease and three areas of unknown but later documented disease were detected after the immunoadsorption process, while the three areas of unknown disease and three of the areas of known disease were not detected in the preclearance images. Thus, the feasibility of using extracorporeal immunoadsorption to improve MoA imaging of tumors was demonstrated.
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Tchurikov NA, Gerasimova TI, Johnson TK, Barbakar NI, Kenzior AL, Georgiev GP. Mobile elements and transposition events in the cut locus of Drosophila melanogaster. MOLECULAR & GENERAL GENETICS : MGG 1989; 219:241-8. [PMID: 2559313 DOI: 10.1007/bf00261183] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have cloned from the Oregon R strain of Drosophila melanogaster a 240 kb segment of DNA that contains the cut (ct) locus, and characterized the region for the presence of repetitive elements. Within this region at least five copies of the suffix element were detected, as well as several putatively novel mobile elements. A number of mutations obtained from the unstable ctMR2 strain and its derivatives were mapped within the cut locus. Comparison between parental and daughter strains indicates that frequently two or more independent transposition events involving the cut locus occur simultaneously within a single germ cell, thus providing a molecular basis for the transposition explosion phenomenon.
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Sirr SA, Johnson TK, Stuart DD, Stanchfield WR, Cardella JF, duCret RP, Boudreau RJ. An improved radiolabeling technique of ivalon and its use for dynamic monitoring of complications during therapeutic transcatheter embolization. J Nucl Med 1989; 30:1399-404. [PMID: 2754493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Transcatheter embolization by Ivalon particles for treatment of arteriovenous malformations has been an accepted therapeutic technique for many years. We describe a new and efficient radiolabeling technique of Ivalon particles using [99mTc]sulfur colloid. Continuous and dynamic monitoring of injected radiolabeled Ivalon particles is made possible by viewing the persistence scope of a portable gamma camera whose head is positioned over the patient undergoing therapeutic embolization. Therefore, if inadvertent pulmonary embolism or reflux migration of radiolabeled Ivalon particles has occurred, the angiographer is immediately aware of this potentially serious or fatal complication and can take corrective action. We describe two patients, each with an arteriovenous malformation, who had therapeutic embolization with radiolabeled Ivalon particles, one resulting in reflux migration and the other resulting in inadvertent pulmonary embolism.
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Johnson TK, Coulter SE, Sirr SA. The "Harlequin" artifact: cause and correction. J Nucl Med 1989; 30:1133-4. [PMID: 2786951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Brown SJ, Rhoads DD, Stewart MJ, Van Slyke B, Chen IT, Johnson TK, Denell RE, Roufa DJ. Ribosomal protein S14 is encoded by a pair of highly conserved, adjacent genes on the X chromosome of Drosophila melanogaster. Mol Cell Biol 1988; 8:4314-21. [PMID: 3141788 PMCID: PMC365504 DOI: 10.1128/mcb.8.10.4314-4321.1988] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We describe a Drosophila DNA clone of tandemly duplicated genes encoding an amino acid sequence nearly identical to human ribosomal protein S14 and yeast rp59. Despite their remarkably similar exons, the locations and sizes of introns differ radically among the Drosophila, human, and yeast (Saccharomyces cerevisiae) ribosomal protein genes. Transcripts of both Drosophila RPS14 genes were detected in embryonic and adult tissues and are the same length as mammalian S14 message. Drosophila RPS14 was mapped to region 7C5-9 on the X chromosome. This interval also encodes a previously characterized Minute locus, M(1)7C.
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Johnson TK, Hasegawa DL, Sklar J, Hendee WR, Steele PP. Early description of "bull's-eye" plot for emission cardiac tomography. J Nucl Med 1988; 29:267-8. [PMID: 3279169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Johnson TK, Yuen KC, Denell RE, Consigli RA. Efficient transfer of proteins from acetic acid-urea and isoelectric-focusing gels to nitrocellulose membrane filters with retention of protein antigenicity. Anal Biochem 1983; 133:126-31. [PMID: 6638475 DOI: 10.1016/0003-2697(83)90232-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A method which facilitates the rapid and quantitative electrophoretic transfer of proteins from gels not containing sodium dodecyl sulfate (SDS) to nitrocellulose membranes is described. The equilibration of non-SDS-polyacrylamide gel electrophoretic gels in a buffer containing SDS confers a net negative charge to the proteins present, presumably as a result of the formation of SDS-protein complexes. Proteins from gels equilibrated in the SDS buffer and then electroblotted in a Tris-glycine buffer at pH 8.3 are transferred with much greater efficiency than are proteins from untreated gels. The method has been shown to significantly enhance the electrophoretic transfer of polyoma viral proteins resolved in either acetic acid-urea or isoelectric-focusing gels to nitrocellulose membranes, and it is suggested that the method should have universal applicability to all gel electrophoresis systems currently employed. The proteins from isoelectric-focusing gels treated with SDS and transferred to nitrocellulose membranes were found to retain antigenicity to antisera prepared against either denatured or native viral proteins.
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Hill JF, Anderson FL, Johnson TK, Rigel LE, Seelye RR. Eighteen-month clinical experience with extended wear silicone contact lenses on 400 patients. AMERICAN JOURNAL OF OPTOMETRY AND PHYSIOLOGICAL OPTICS 1983; 60:578-81. [PMID: 6614134 DOI: 10.1097/00006324-198307000-00004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Four hundred patients wearing silicone elastomer contact lenses for extended wear were monitored over an 18-month period. Safety and efficacy were evaluated as related to corneal physiology and lens performance. These lenses proved to be reasonably durable and the lens material and design characteristics did not interfere with ocular physiology but permitted good visual acuity and comfort. The authors' clinical experiences, when compared with other reports of extended-wear lens designs and materials, indicate that this silicone elastomer lens provides superior performance characteristics.
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Yuen KC, Johnson TK, Denell RE, Consigli RA. A silver-staining technique for detecting minute quantities of proteins on nitrocellulose paper: retention of antigenicity of stained proteins. Anal Biochem 1982; 126:398-402. [PMID: 6186159 DOI: 10.1016/0003-2697(82)90534-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Isackson DR, Johnson TK, Denell RE. Hybrid dysgenesis in Drosophila: the mechanism of T-007-induced male recombination. MOLECULAR & GENERAL GENETICS : MGG 1981; 184:539-43. [PMID: 6801436 DOI: 10.1007/bf00352536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The term "hybrid dysgenesis" describes a syndrome of genetic effects which sometimes results when Drosophila melanogaster from wild populations are outcrossed; this syndrome often includes male recombination as well as enhanced rates of genic and chromosomal mutation, sterility, and transmission ratio distortion. In this study, we have examined the mechanism of T-007-induced male recombination by genetically characterizing third chromosomes generated by an exchange in a well-marked euchromatic region. Most recombinant chromosomes were sequentially normal, and no recessive lethal events at the point of exchange were recovered. The results demonstrate that although some recombinants may be generated by nonhomologous chromosome (or chromatid) breakage and reunion, the predominant effect of T-007 is through an enhanced rate of normal mitotic exchange. The rate of mitotic exchange is also increased by ionizing radiation and chemical mutagens; we suggest that the common factor in all three cases is the induction of single strand breaks.
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