1,206 research outputs found
Iodine Radiolabeled Mesenchymal Stem Cell (MSC)-Exosomes and Their CD73 Enzymatic Activities
No full textIODINE RADIOLABELLED MESENCHYMAL STEM CELL (MSC)-EXOSOMES AND THEIR CD73 ENZYMATIC ACTIVITIES Chang-Tong Yang a,b*,Ruenn Chai Laic, Sai Kiang Limc, David Chee Eng Ng a,b a Department of Nuclear Medicine and Molecular Imaging, Radiological Sciences Division, Singapore General Hospital, Outram Road, 169608 Singapore; b Duke-NUS Medical School, 8 College Road, 169857 Singapore; cInstitute of Molecular & Cell Biology, 8A Biomedical Grove #05-16 Immunos, 138648, Singapore; *[email protected] Introduction MSC-derived exosomes have shown therapeutic potential in the areas of cardiovascular, orthopaedic, ophthalmologic, immune, dermatologic diseases and radiation sickness. Efficient radioisotope-labelling of exosomes remains as a challenging process. We demonstrate iodine-131 radiolabeled exosomes using both chloramine-T and Pierce Iodination methods, and characterized I-labelled exosomes via their CD73 enzymatic activities. Experimental methodology and results Two classic radio-iodination methods have been used to label exosomes due to several advantages: relatively long half-life of I-131 (half-life 8 days) and I-124 (half-life 4.2 days, 25.6% positron emission) could enable a desired tracking kinetics of exosomes in vitro and in vivo; radiolabeling of iodine to peptides and antibodies is a well-established chemistry; the unlabeled free iodine after radio-labelling can be easily removed to reach high radiochemical purity. By using chloramine-T, the radiolabeling yield of 131I-labeled-exosomes achieved ~30-40% with a radiochemical purity > 90% after running through PD10 column purification. Using Pierce Iodination, the radiolabeling yield drops to ~15-20%, radiochemical purity achieved >90% after the same purification process. The integrity of I-labeled-exosomes is important in the reproducibility and development of exosome clinical therapeutics. No radioactive iodine was labelled to exosome for characterization of their integrity. The results showed that chloramine T radiolabeling affected the structures of I-labeled-exosomes as the CD73 enzymatic activity of I-labeled exosomes was destroyed, the particle size became much larger and caused broader exosome size distribution. While with Pierce iodination the CD73 activity drops by 50 % when compared to that of the unlabeled exosomes, and the particles kept the same size. Conclusions Using chloramine T method showed that the CD73 enzymatic activity of I-labelled exosomes was destroyed, suggesting the labeling process damaged the structure of exosomes. By comparison, using Pierce Iodination method preserved the CD73 enzymatic activity, indicating that exosomes can be radiolabeled using Pierce Iodination for in vitro and in vivo tracking and pharmacokinetic studies
Iodine Radiolabeled Mesenchymal Stem Cell (MSC)-Exosomes and Their CD73 Enzymatic Activities
No full textIODINE RADIOLABELLED MESENCHYMAL STEM CELL (MSC)-EXOSOMES AND THEIR CD73 ENZYMATIC ACTIVITIES Chang-Tong Yang a,b*,Ruenn Chai Laic, Sai Kiang Limc, David Chee Eng Ng a,b a Department of Nuclear Medicine and Molecular Imaging, Radiological Sciences Division, Singapore General Hospital, Outram Road, 169608 Singapore; b Duke-NUS Medical School, 8 College Road, 169857 Singapore; cInstitute of Molecular & Cell Biology, 8A Biomedical Grove #05-16 Immunos, 138648, Singapore; *[email protected] Introduction MSC-derived exosomes have shown therapeutic potential in the areas of cardiovascular, orthopaedic, ophthalmologic, immune, dermatologic diseases and radiation sickness. Efficient radioisotope-labelling of exosomes remains as a challenging process. We demonstrate iodine-131 radiolabeled exosomes using both chloramine-T and Pierce Iodination methods, and characterized I-labelled exosomes via their CD73 enzymatic activities. Experimental methodology and results Two classic radio-iodination methods have been used to label exosomes due to several advantages: relatively long half-life of I-131 (half-life 8 days) and I-124 (half-life 4.2 days, 25.6% positron emission) could enable a desired tracking kinetics of exosomes in vitro and in vivo; radiolabeling of iodine to peptides and antibodies is a well-established chemistry; the unlabeled free iodine after radio-labelling can be easily removed to reach high radiochemical purity. By using chloramine-T, the radiolabeling yield of 131I-labeled-exosomes achieved ~30-40% with a radiochemical purity > 90% after running through PD10 column purification. Using Pierce Iodination, the radiolabeling yield drops to ~15-20%, radiochemical purity achieved >90% after the same purification process. The integrity of I-labeled-exosomes is important in the reproducibility and development of exosome clinical therapeutics. No radioactive iodine was labelled to exosome for characterization of their integrity. The results showed that chloramine T radiolabeling affected the structures of I-labeled-exosomes as the CD73 enzymatic activity of I-labeled exosomes was destroyed, the particle size became much larger and caused broader exosome size distribution. While with Pierce iodination the CD73 activity drops by 50 % when compared to that of the unlabeled exosomes, and the particles kept the same size. Conclusions Using chloramine T method showed that the CD73 enzymatic activity of I-labelled exosomes was destroyed, suggesting the labeling process damaged the structure of exosomes. By comparison, using Pierce Iodination method preserved the CD73 enzymatic activity, indicating that exosomes can be radiolabeled using Pierce Iodination for in vitro and in vivo tracking and pharmacokinetic studies
Effective acupunture treatment for heart diseases
No full textIn the recent years, the population have been aging and people are more concerned about health. It has become increasingly important for clinical researches to look for remedy and cures for various disease with least side effects and maintain one’s health. Traditional Chinese Medicine (TCM) has become one of the most researched areas of alternate cure for disease. In this report, topics on how TCM and western medical science inter-connects and if acupuncture of TCM has its effects in curing heart disease are discussed and studied.
As the project is focused on heart diseases, it is important to know how the heart functions and the circulation of blood in the human body. Thus the understanding of anatomy and physiology of the cardiovascular system is discussed in the beginning of the report. In addition, the analysis of electrocardiogram and some theories of TCM and Acupuncture are also discussed as literature review.
In addition, an experiment is carried out to test the resistance between main acupuncture meridian points of 10 male volunteers. the description of procedure and an analysis of the results are also included in this report.
This project is still in its primitive stage and therefore, information inside this report should only be taken as a reference and further development of the experiment is encouraged.Bachelor of Engineerin
The value of silence
No full textThis is an electronic version of the article published in Theatre Journal, 54(1):85-94, 2002 March. The published article is available at http://muse.jhu.edu/journals/theatre_journal/v054/54.1eng.pdfEng, David L.The Value of Silence.Theatre Journal, 54,(1):85-94, 2002.DOI: 10.1353/tj.2002.000
Lumped-parameter model of renal hemodynamics
No full textThe blood flow through a porous and distensible vessel such as a glomerular capillary is studied using a lumped-parameter model, and based on simplified Navier-Stokes’ equations to derive the governing equations in the form of second-order hyperbolic partial differential equations in pressure. Further modelling of the autoregulation of flow is performed based on a extravascular tissue-pressure model. Lumped-parameter model of a compliant, porous vescular compartment was studied through simplification of Navier-Stokes equation where hyperbolic second-order partial differential equations governing flow and pressure were derived.Master of Science (Biomedical Engineering
Prescribing Practices of Australian Dispensing Doctors
No full textThe attached document may provide the author's accepted version of a published work. See Citation for details of the published work.
InGaAs/AlGaAsSb avalanche photodiode with high gain - bandwidth product
No full textIncreasing reliance on the Internet places greater and greater demands for high -speed optical communication systems. Increasing their data transfer rate allows more data to be transferred over existing links. With optical receivers being essential to all optical links, bandwidth performance of key components in receivers, such as avalanche photodiodes (APDs), must be improved. The APDs rely on In0.53Ga0.47As (grown lattice-matched to InP substrates) to efficiently absorb and detect the optical signals with 1310 or 1550 nm wavelength, the optimal wavelengths of operation for these optical links. Thus developing InP -compatible APDs with high gain-bandwidth product (GBP) is important to the overall effort of increasing optical links’ data transfer rate. Here we demonstrate a novel InGaAs/AlGaAsSb APD, grown on an InP substrate, with a GBP of 424 GHz, the highest value reported for InP -compatible APDs, which is clearly applicable to future optical communication systems at or above 10 Gb/s
A Tribute to Emeritus Professor David Tall: A Mentor, Scholar, and Academic Father
No full textThis tribute reflects on the life and contributions of Emeritus Professor David Tall, a distinguished scholar in Mathematical Thinking and Mathematics Education, who passed away on July 15, 2024. David Tall’s groundbreaking ideas, such as concept image, procept, and the three worlds of mathematics, have profoundly influenced the mathematics education community. His philosophy of reciprocal learning and encouragement of innovative research shaped many scholars, including the author, who considers him not only a supervisor but an academic father. David\u27s legacy will continue to inspire future generations in academia
Effective acupuncture back pain treatment
No full textThis final year report aims to identify the effective acupuncture points for the back pain treatment and develop an intelligent software consultant package. First of all, a brief introduction of the report is introduced. It followed by the literature review in Chapter 2. In the following chapter, literature survey for effective acupuncture for back pain treatment was conducted and a result of 15 common acupuncture points has been identified. In order to provide acupuncture treatment recommendations to TCM practitioners, a system consists of syndromes, diagnosis and acupuncture treatment recommendation is developed. In Chapter 4, based on the information found in previous chapter, the basic design of the intelligent system is discussed. However, due to time constraint, the development of web-based intelligent software consultation package has not been completed yet. An investigation on the body impedance between effective acupuncture points for back pain treatment is carried on in Chapter 5. A conclusion which consists of project summary, knowledge gained by the author and further improvements is made in the last chapter.Bachelor of Engineerin
Pulmonary trematodosis (Pharyngostomoides sp.) in a juvenile raccoon (Procyon lotor)
No full text© 2011 The Author(s)Accession Number: 21908291. Language: English. Language Code: eng. Date Created: 20110912. Date Completed: 20120113. Update Code: 20120113. Publication Type: Case Reports; Journal Article. Journal ID: 9011490. Publication Model: Print. Cited Medium: Internet. NLM ISO Abbr: J. Vet. Diagn. Invest. Linking ISSN: 10406387. Subset: IM. Date of Electronic Publication: 20110501; ID: 21908291Source type: Electronic(1
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