263 results on '"Sze D"'
Search Results
252. Percutaneous treatment of bronchial artery aneurysm with use of transcatheter coil embolization and thoracic aortic stent-graft placement.
- Author
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Sakai T, Razavi MK, Semba CP, Kee ST, Sze DY, and Dake MD
- Subjects
- Aged, Embolization, Therapeutic instrumentation, Humans, Male, Polytetrafluoroethylene, Prosthesis Design, Aneurysm therapy, Aorta, Thoracic pathology, Blood Vessel Prosthesis Implantation, Bronchial Arteries pathology, Embolization, Therapeutic methods, Stents
- Published
- 1998
- Full Text
- View/download PDF
253. Superior vena cava syndrome after heart transplantation: percutaneous treatment of a complication of bicaval anastomoses.
- Author
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Sze DY, Robbins RC, Semba CP, Razavi MK, and Dake MD
- Subjects
- Adult, Anastomosis, Surgical adverse effects, Female, Follow-Up Studies, Humans, Infant, Newborn, Male, Middle Aged, Phlebography, Plasminogen Activators administration & dosage, Plasminogen Activators therapeutic use, Postoperative Complications, Superior Vena Cava Syndrome diagnostic imaging, Superior Vena Cava Syndrome therapy, Urokinase-Type Plasminogen Activator administration & dosage, Urokinase-Type Plasminogen Activator therapeutic use, Angioplasty, Balloon, Heart Transplantation adverse effects, Stents, Superior Vena Cava Syndrome etiology, Thrombolytic Therapy, Venae Cavae surgery
- Abstract
Objectives: Our objectives were (1) to investigate the incidence and cause of symptomatic superior vena caval anastomotic stenosis and central venous thrombosis in patients receiving heart or heart-lung transplantation and (2) to explore percutaneous methods of thrombolysis and endoluminal intervention to treat these complications., Methods: Review of 1016 cases revealed three cases of superior vena cava syndrome. Anatomy, surgical technique, and medical risk factors were examined. Percutaneous treatments, including urokinase thrombolysis, mechanical thrombolysis, balloon angioplasty, and stent placement, were attempted., Results: All three of these patients underwent transplantation by means of the bicaval anastomotic technique. In addition, the diameters of the donor and recipient cavae were grossly mismatched in all three. Stenoses in all three patients were successfully treated percutaneously with balloon angioplasty and stent placement. Treatment of the accompanying large-volume thrombosis was problematic in these patients, and two had hemorrhagic complications of urokinase thrombolysis. A mechanical thrombolysis device was used successfully in the third patient., Conclusions: Anastomotic stricture and central venous thrombosis is an uncommon complication of the bicaval anastomotic technique of heart and heart-lung transplantation. Discrepancy between donor and recipient caval diameters appears to be the major risk factor. Endoluminal thrombolysis and stenting provides rapid and enduring relief of symptoms and precludes repeat sternotomy, cardiopulmonary bypass, and general anesthesia.
- Published
- 1998
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- View/download PDF
254. T helper 1 (Th1) and Th2 characteristics start to develop during T cell priming and are associated with an immediate ability to induce immunoglobulin class switching.
- Author
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Toellner KM, Luther SA, Sze DM, Choy RK, Taylor DR, MacLennan IC, and Acha-Orbea H
- Subjects
- Animals, Bordetella pertussis immunology, Germinal Center immunology, Haptens immunology, Interferon-gamma biosynthesis, Interleukin-4 biosynthesis, Lymph Nodes cytology, Lymph Nodes immunology, Mammary Tumor Virus, Mouse immunology, Mice, Mice, Inbred BALB C, Plasma Cells, Spleen cytology, Spleen immunology, gamma-Globulins immunology, Immunoglobulin Class Switching, Lymphocyte Activation, Th1 Cells, Th2 Cells, Vaccination
- Abstract
The respective production of specific immunoglobulin (Ig)G2a or IgG1 within 5 d of primary immunization with Swiss type mouse mammary tumor virus [MMTV(SW)] or haptenated protein provides a model for the development of T helper 1 (Th1) and Th2 responses. The antibody-producing cells arise from cognate T cell B cell interaction, revealed by the respective induction of Cgamma2a and Cgamma1 switch transcript production, on the third day after immunization. T cell proliferation and upregulation of mRNA for interferon gamma in response to MMTV(SW) and interleukin 4 in response to haptenated protein also starts during this day. It follows that there is minimal delay in these responses between T cell priming and the onset of cognate interaction between T and B cells leading to class switching and exponential growth. The Th1 or Th2 profile is at least partially established at the time of the first cognate T cell interaction with B cells in the T zone. The addition of killed Bordetella pertussis to the hapten-protein induces nonhapten-specific IgG2a and IgG1 plasma cells, whereas the anti-hapten response continues to be IgG1 dominated. This indicates that a Th2 response to hapten-protein can proceed in a node where there is substantial Th1 activity.
- Published
- 1998
- Full Text
- View/download PDF
255. The changing preference of T and B cells for partners as T-dependent antibody responses develop.
- Author
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MacLennan IC, Gulbranson-Judge A, Toellner KM, Casamayor-Palleja M, Chan E, Sze DM, Luther SA, and Orbea HA
- Subjects
- Animals, B-Lymphocytes cytology, Cell Movement, Dendritic Cells immunology, Humans, Lymphocyte Activation, Receptors, Antigen, B-Cell immunology, T-Lymphocytes cytology, Antibody Formation immunology, B-Lymphocytes immunology, T-Lymphocytes immunology
- Abstract
Recirculating virgin CD4+ T cells spend their life migrating between the T zones of secondary lymphoid tissues where they screen the surface of interdigitating dendritic cells. T-cell priming starts when processed peptides or superantigen associated with class II MHC molecules are recognised. Those primed T cells that remain within the lymphoid tissue move to the outer T zone, where they interact with B cells that have taken up and processed antigen. Cognate interaction between these cells initiates immunoglobulin (Ig) class switch-recombination and proliferation of both B and T cells; much of this growth occurs outside the T zones B cells migrate to follicles, where they form germinal centres, and to extrafollicular sites of B-cell growth, where they differentiate into mainly short-lived plasma cells. T cells do not move to the extrafollicular foci, but to the follicles; there they proliferate and are subsequently involved in the selection of B cells that have mutated their Ig variable-region genes. During primary antibody responses T-cell proliferation in follicles produces many times the peak number of T cells found in that site: a substantial proportion of the CD4+ memory T-cell pool may originate from growth in follicles.
- Published
- 1997
- Full Text
- View/download PDF
256. Immunoglobulin switch transcript production in vivo related to the site and time of antigen-specific B cell activation.
- Author
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Toellner KM, Gulbranson-Judge A, Taylor DR, Sze DM, and MacLennan IC
- Subjects
- Animals, B-Lymphocytes cytology, Base Sequence, Cell Differentiation, Cell Movement, Chickens, DNA Primers, Female, Immunoglobulin G classification, Introns, Kinetics, Mice, Mice, Inbred Strains, Molecular Sequence Data, Polymerase Chain Reaction, Spleen cytology, Spleen immunology, Time Factors, gamma-Globulins immunology, gamma-Globulins pharmacology, Antibody Formation, Antigens pharmacology, B-Lymphocytes immunology, Immunoglobulin Class Switching, Immunoglobulin G biosynthesis, Lymphocyte Activation, Plasma Cells immunology, Transcription, Genetic drug effects
- Abstract
Immunoglobulin (Ig) class switch recombination is associated with the production and splicing of germline IgCH messenger RNA transcripts. Levels of gamma 1 transcripts in mouse spleen sections were assessed by semiquantitative analysis of reverse transcriptase polymerase chain reaction (PCR) products during primary and secondary antibody responses to chicken gamma globulin (CGG). This was correlated with the appearance of CGG-specific B cells and their growth and differentiation to plasma cells. After primary immunization with CGG, gamma 1 switch transcripts appeared after 4 d, peaked at a median of six times starting levels between 10 and 18 d after immunization, and returned to background levels before secondary immunization at 5 wk. By contrast, after secondary challenge with CGG, a sevenfold increase in transcripts occurs during the first d. The level again doubles by day 3, when it is six times that which is seen at the peak of the primary response. After day 4, there was a gradual decline over the next 2-3 wk. Within 12 h of secondary immunization, antigen-specific memory B cells appeared in the outer I zone and by 24 h entered S phase, presumably as a result of cognate interaction with primed T cells. Over the next few hours, they migrated to the edge of the red pulp, where they grew exponentially until the fourth day, when they synchronously differentiated to become plasma cells. The same pattern was seen for the migration, growth, and differentiation of virgin hapten-specific B cells when CGG-primed mice were challenged with hapten protein. The continued production of transcripts after day 3 indicates that switching also occurs in germinal centers, but in a relatively small proportion of their B cells. The impressive early production of switch transcripts during T cell-dependent antibody responses occurs in cells that are about to undergo massive clonal expansion. It is argued that Ig class switching at this time, which is associated with cognate T cell-B cell interaction in the T zone, has a major impact on the class and subclasses of Ig produced during the response.
- Published
- 1996
- Full Text
- View/download PDF
257. Musculoskeletal MR imaging: turbo (fast) spin-echo versus conventional spin-echo and gradient-echo imaging at 0.5 tesla.
- Author
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Vahlensieck M, Lang P, Seelos K, Yang-Ho Sze D, Grampp S, and Reiser M
- Subjects
- Adolescent, Adult, Aged, Artifacts, Child, Child, Preschool, Female, Humans, Male, Middle Aged, Prospective Studies, Sensitivity and Specificity, Magnetic Resonance Imaging methods, Musculoskeletal System pathology
- Abstract
The value of T2-weighted fast spin-echo imaging of the musculoskeletal system was assessed in 22 patients with various neoplastic, inflammatory, and traumatic disorders. Images were acquired with high echo number (i.e., echo train length) fast spin-echo (FSE; TR 2000 ms, effective TE 100 ms, echo number 13, linear k-space ordering), conventional spin-echo (SE; TR 2000 ms, TE 100 ms) and gradient-echo (GRE) sequences (TR 600 ms, TE 34 ms, flip angle 25 degrees). Signal intensities, signal-to-noise ratios, contrast, contrast-to-noise ratios, lesion conspicuousness, detail perceptibility, and sensitivity towards image artifacts were compared. The high signal intensity of fat on FSE images resulted in a slightly inferior lesion-to-fat contrast on FSE images. However, on the basis of lesion conspicuity, FSE is able to replace time-consuming conventional T2-weighted SE imaging in musculoskeletal MRI. In contrast, GRE images frequently showed superior lesion conspicuity. One minor disadvantage of FSE in our study was the frequent deterioration of image quality by blurring, black band, and rippling artifacts. Some of these artifacts, however, can be prevented using short echo trains and/or short echo spacings.
- Published
- 1994
- Full Text
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258. High-resolution proton NMR studies of lymphocyte extracts.
- Author
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Sze DY and Jardetzky O
- Subjects
- Animals, Blood Cells chemistry, Cell Extracts chemistry, Cell Fractionation, Humans, Lymphocyte Activation, Mice, Lymphocytes chemistry, Magnetic Resonance Spectroscopy
- Abstract
Anatomic imaging is now a well-developed application of magnetic resonance. Greater capabilities for physiologic characterization should become possible by concomitant application of spectroscopic methods. High-resolution in vitro spectroscopy must first provide a framework upon which in vivo and diagnostic interpretation may be based. Biochemical profiles consisting of quantitation of extracted aqueous metabolites and lipids of particular cells or organs establish an in vitro glossary for what may be found in the intact cell or living subject. A large variety of amino acids, intermediary metabolites, membrane precursors, and nucleotides are detectable in extracts of human peripheral blood lymphocytes, and significant changes in intracellular concentrations have been monitored after lectin-induced activation. Corresponding changes in lipid profile have also been noted. An increasing variety of other cells and tissues are being similarly characterized. Despite its limitations, NMR analysis possesses the unique prospect of providing a noninvasive and nondestructive source of biochemical information.
- Published
- 1994
- Full Text
- View/download PDF
259. Determination of metabolite and nucleotide concentrations in proliferating lymphocytes by 1H-NMR of acid extracts.
- Author
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Sze DY and Jardetzky O
- Subjects
- Cells, Cultured, Chromatography, High Pressure Liquid, Edetic Acid pharmacology, Erythrocytes metabolism, Humans, Hydrogen, Leukocyte Count, Lymphocyte Activation, Magnetic Resonance Spectroscopy, Neutrophils metabolism, Amino Acids metabolism, Carbohydrate Metabolism, Fatty Acids metabolism, Lymphocytes metabolism, Nucleotides metabolism
- Abstract
Nuclear magnetic resonance (NMR) studies of extracts have proven to be a powerful window onto the intracellular machinery of cells and tissues. The major advantages of in vitro 1H-NMR, namely chemical preservation, simultaneous detection, identification, and quantitation of compounds, and sensitivity to a large variety of classes of compounds, are employed in this study to characterize the metabolic course of mitogen-stimulated proliferation of human peripheral lymphocytes. A reliable method to quantitate amino acids, metabolic intermediates, soluble membrane lipid precursors, and purine, pyridine and pyrimidine nucleotides is presented, using samples as small as 30 mg wet weight. A total of 53 substances were detected in lymphocytes and other blood cells. During the course of lymphocyte culture, changes in intracellular concentrations of lactate, taurine, inositol and nucleotides, including NAD, IMP and high-energy phosphates, were especially marked. 1H-NMR compares favorably to 31P-NMR and to HPLC, and is especially attractive in light of expectations for future in vivo application.
- Published
- 1990
- Full Text
- View/download PDF
260. Characterization of lipid composition in stimulated human lymphocytes by 1H-NMR.
- Author
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Sze DY and Jardetzky O
- Subjects
- Cell Membrane analysis, Cells, Cultured, Cholesterol analysis, Humans, Hydrogen, Lymphocyte Activation, Magnetic Resonance Spectroscopy, Membrane Lipids analysis, Phospholipids analysis, Lipids analysis, Lymphocytes analysis
- Abstract
Recent in vivo NMR studies have raised interest in the structural changes of cellular lipids during proliferative activity. We investigated the changes in plasma membrane lipid and total cell lipid during mitogenically-stimulated proliferation of human peripheral blood lymphocytes by extraction of lipids and assay by 500 MHz 1H-NMR. Resonances were assigned using one- and two-dimensional spectroscopic techniques, and signals unique to certain species of lipid were identified. Choline and ethanolamine-containing lipids, glycerophospholipid backbones, sphingolipids, cholesterol, plasmalogens and triacylglycerols were readily detected. Resolution of a number of lipid species was not possible, despite the use of high-resolution techniques. NMR values for proliferation-induced changes in the most easily determined parameters, namely the total cholesterol to total phospholipid molar ratio, and phosphatidylcholine, phosphatidylethanolamine and sphingolipid composition, were found to agree with traditional methods. Differences in phospholipid and fatty acid profiles were found between plasma membranes and total cell lipid for resting values and for response to mitogen.
- Published
- 1990
- Full Text
- View/download PDF
261. Inhibition of lymphocyte stimulation by shift reagents.
- Author
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Sze DY, Corbelletta NL, Shochat SJ, and Jardetzky O
- Subjects
- Chelating Agents adverse effects, Chelating Agents pharmacology, Humans, Indicators and Reagents adverse effects, Indicators and Reagents pharmacology, Lymphocyte Culture Test, Mixed, Lymphocytes drug effects, Metals, Rare Earth, Mitogens antagonists & inhibitors, Mitogens pharmacology, Lymphocyte Activation drug effects, Magnetic Resonance Spectroscopy
- Abstract
Lanthanide shift reagents have opened a new avenue in the study of membrane biochemistry, but their stabilities and biological reactivities remain questionable. We present evidence that shift reagents are not biologically inert, and that they exhibit the ability to inhibit stimulation of human peripheral lymphocytes at commonly used concentrations. A survey of various mitogens yielded no shift reagent-resistant modes of stimulation, and a survey of various shift reagents yielded no effective and nontoxic alternatives. Involvement of calcium-regulating mechanisms was not apparent. The assumption that lanthanide shift reagents used in NMR studies are nondestructive and physiologically innocuous is thus shown to be unwarranted.
- Published
- 1990
- Full Text
- View/download PDF
262. Sodium/proton antiport is required for growth of Escherichia coli at alkaline pH.
- Author
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McMorrow I, Shuman HA, Sze D, Wilson DM, and Wilson TH
- Subjects
- Amiloride pharmacology, Culture Media, Escherichia coli genetics, Escherichia coli metabolism, Growth Inhibitors pharmacology, Hydrogen-Ion Concentration, Lithium pharmacology, Mutation, Sodium pharmacology, Sodium-Hydrogen Exchangers, Carrier Proteins physiology, Escherichia coli growth & development
- Abstract
Evidence is presented indicating that Escherichia coli requires the Na+/H+ antiporter and external sodium (or lithium) ion to grow at high pH. Cells were grown in plastic tubes containing medium with a very low Na+ content (5-15 microM). Normal cells grew at pH 7 or 8 with or without added Na+, but at pH 8.5 external Na was required for growth. A mutant with low antiporter activity failed to grow at pH 8.5 with or without Na+. On the other hand, another mutant with elevated antiporter activity grew at a higher pH than normal (pH 9) in the presence of added Na+ or Li+. Amiloride, an inhibitor of the antiporter, prevented cells from growing at pH 8.5 (plus Na+), although it had no effect on growth in media of lower pH values.
- Published
- 1989
- Full Text
- View/download PDF
263. Measurement of the sodium membrane potential by NMR.
- Author
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Cowan BE, Sze DY, Mai MT, and Jardetzky O
- Subjects
- Erythrocyte Membrane physiology, Humans, Magnetic Resonance Spectroscopy, Membrane Potentials, Sodium blood
- Abstract
Using nuclear magnetic resonance (NMR), we have developed a method of noninvasively determining the transmembrane sodium potential in erythrocytes by measuring intracellular and extracellular sodium concentrations. The experimental values correlated well with values obtained from standard flame photometric methods.
- Published
- 1985
- Full Text
- View/download PDF
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