Zhaoda Zhang - Academia.edu (original) (raw)
Papers by Zhaoda Zhang
Molecular Imaging and Biology
Life
Islet transplantation has great potential as a cure for type 1 diabetes. At present; the lack of ... more Islet transplantation has great potential as a cure for type 1 diabetes. At present; the lack of a clinically validated non-invasive imaging method to track islet grafts limits the success of this treatment. Some major clinical imaging modalities and various molecular probes, which have been studied for non-invasive monitoring of transplanted islets, could potentially fulfill the goal of understanding pathophysiology of the functional status and viability of the islet grafts. In this current review, we summarize the recent clinical studies of a variety of imaging modalities and molecular probes for non-invasive imaging of transplanted beta cell mass. This review also includes discussions on in vivo detection of endogenous beta cell mass using clinical imaging modalities and various molecular probes, which will be useful for longitudinally detecting the status of islet transplantation in Type 1 diabetic patients. For the conclusion and perspectives, we highlight the applications of m...
ChemInform
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Allosterism in Drug Discovery, 2000
Tetrahedron Letters, 1996
A new phosphitylating reagent, 2-cyanoethoxy(N,N-diisopropylamino)3-nitro-1,2,4-triazolylphosphin... more A new phosphitylating reagent, 2-cyanoethoxy(N,N-diisopropylamino)3-nitro-1,2,4-triazolylphosphine (1), has been prepared and effectively used in in situ generation of 5′-DMT-nucleoside phosphoramidites and automated syntheses of oligonucleotides.
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2013
Journal of Organic Chemistry, 1988
New Journal of Chemistry, Apr 1, 2010
A strategy for preparing high relaxivity, metabolically stable peptide-based MR contrast agents i... more A strategy for preparing high relaxivity, metabolically stable peptide-based MR contrast agents is described. The chemical and topological diversity of peptides offer tremendous possibilities to identify new diagnostic imaging compounds. Peptides have been widely used to target an imaging probe to a specific protein or receptor and thereby provide greater specificity. Typically an imaging reporting moiety (e.g. positron emitter, gamma emitter, paramagnetic ion, near infrared fluorophore) is conjugated to the peptide. The site of conjugation, the linker, and the type of imaging reporter all play a role in determining biological activity and pharmacokinetics. 1, 2 For peptide-based magnetic resonance imaging (MRI) contrast agents, an additional factor is detection sensitivity of the imaging probe. 3 Multiple copies of the MR active reporter, typically a gadolinium complex, are required to provide robust image contrast. An additional major challenge to creating new drugs from peptides is peptide degradation by endogenous peptidases. There are numerous medicinal chemistry approaches to improve peptide stability, biological activity, and/or bioavailability that increase in complexity from modified peptides to pseudopeptides to small molecule peptidomimetics. 4, 5 In this report, we explore the potential of using the imaging reporter to block peptidase activity. We, 6-9 and others, 10-14 have been interested in developing gadolinium-based peptide-targeted MR imaging agents. Compared to other modalities, MRI provides a favorable combination of high spatial resolution, depth penetration, and lack of ionizing radiation. Unlike nanoparticles, these relatively small molecules can rapidly reach targets in extravascular spaces and can be readily excreted through the kidneys to reduce/avoid long-term gadolinium retention and toxicity. On the other hand, extravasation into the kidneys and liver exposes these compounds to a range of peptidases. There is some flexibility as to where and how the gadolinium chelates are conjugated to the peptide. Conjugation is possible at the Nor C-terminus and/or within the peptide structure. 6 We recently reported some fibrin-specific peptides conjugated with one or four [Gd (DTPA)] 2− moieties. 8 The construct with highest affinity had two peptides linked via their Nterminus to a GdDTPA tetramer, i.e. Pep N-Gd 4-N Pep, termed EP-1084
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2013
Molecular Imaging and Biology
Life
Islet transplantation has great potential as a cure for type 1 diabetes. At present; the lack of ... more Islet transplantation has great potential as a cure for type 1 diabetes. At present; the lack of a clinically validated non-invasive imaging method to track islet grafts limits the success of this treatment. Some major clinical imaging modalities and various molecular probes, which have been studied for non-invasive monitoring of transplanted islets, could potentially fulfill the goal of understanding pathophysiology of the functional status and viability of the islet grafts. In this current review, we summarize the recent clinical studies of a variety of imaging modalities and molecular probes for non-invasive imaging of transplanted beta cell mass. This review also includes discussions on in vivo detection of endogenous beta cell mass using clinical imaging modalities and various molecular probes, which will be useful for longitudinally detecting the status of islet transplantation in Type 1 diabetic patients. For the conclusion and perspectives, we highlight the applications of m...
ChemInform
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Allosterism in Drug Discovery, 2000
Tetrahedron Letters, 1996
A new phosphitylating reagent, 2-cyanoethoxy(N,N-diisopropylamino)3-nitro-1,2,4-triazolylphosphin... more A new phosphitylating reagent, 2-cyanoethoxy(N,N-diisopropylamino)3-nitro-1,2,4-triazolylphosphine (1), has been prepared and effectively used in in situ generation of 5′-DMT-nucleoside phosphoramidites and automated syntheses of oligonucleotides.
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2013
Journal of Organic Chemistry, 1988
New Journal of Chemistry, Apr 1, 2010
A strategy for preparing high relaxivity, metabolically stable peptide-based MR contrast agents i... more A strategy for preparing high relaxivity, metabolically stable peptide-based MR contrast agents is described. The chemical and topological diversity of peptides offer tremendous possibilities to identify new diagnostic imaging compounds. Peptides have been widely used to target an imaging probe to a specific protein or receptor and thereby provide greater specificity. Typically an imaging reporting moiety (e.g. positron emitter, gamma emitter, paramagnetic ion, near infrared fluorophore) is conjugated to the peptide. The site of conjugation, the linker, and the type of imaging reporter all play a role in determining biological activity and pharmacokinetics. 1, 2 For peptide-based magnetic resonance imaging (MRI) contrast agents, an additional factor is detection sensitivity of the imaging probe. 3 Multiple copies of the MR active reporter, typically a gadolinium complex, are required to provide robust image contrast. An additional major challenge to creating new drugs from peptides is peptide degradation by endogenous peptidases. There are numerous medicinal chemistry approaches to improve peptide stability, biological activity, and/or bioavailability that increase in complexity from modified peptides to pseudopeptides to small molecule peptidomimetics. 4, 5 In this report, we explore the potential of using the imaging reporter to block peptidase activity. We, 6-9 and others, 10-14 have been interested in developing gadolinium-based peptide-targeted MR imaging agents. Compared to other modalities, MRI provides a favorable combination of high spatial resolution, depth penetration, and lack of ionizing radiation. Unlike nanoparticles, these relatively small molecules can rapidly reach targets in extravascular spaces and can be readily excreted through the kidneys to reduce/avoid long-term gadolinium retention and toxicity. On the other hand, extravasation into the kidneys and liver exposes these compounds to a range of peptidases. There is some flexibility as to where and how the gadolinium chelates are conjugated to the peptide. Conjugation is possible at the Nor C-terminus and/or within the peptide structure. 6 We recently reported some fibrin-specific peptides conjugated with one or four [Gd (DTPA)] 2− moieties. 8 The construct with highest affinity had two peptides linked via their Nterminus to a GdDTPA tetramer, i.e. Pep N-Gd 4-N Pep, termed EP-1084
Society of Nuclear Medicine Annual Meeting Abstracts, May 1, 2013