2,997 research outputs found
Glucagon-like peptide-1 receptor imaging for localization of insulinomas
No full textThe surgical removal of insulinomas is hampered by difficulties to localize it using conventional radiological procedures. Recently these tumors were shown to exhibit a very high density of glucagon-like peptide-1 receptors (GLP-1R) in vitro that may be used as specific targets for in vivo receptor radiolabeling
TARGETING PEPTIDES CONTAINING SUPRAMOLECULAR AGGREGATES TOWARD CANCER CELLS
No full textMultimodal supramolecular compounds that combine imaging and therapeutic capabilities are the focus of intensive research for applications in the growing field of nanomedicine. These compounds offer the prospect to increase diagnostic accuracy and therapeutic effectiveness, while minimizing side effects from treatment. Nanoparticles with a micellar or liposomal structure obtained by assembling amphiphilic compounds are promising candidates for such multifunctional therapeutic platforms.
Selective target of these nanoparticles for cancer cells can be obtained by labeling supramolecular aggregates with peptides able to recognize transmembrane receptors overexpressed in many human tumors. Examples of peptide that can be used to drive selectively the nanoparticle on the cancer cells are the octreotide (analog of the somatostatin), [7-14] bombesin and CCK8 peptides. To reach this result, new amphiphilic monomers were designed, synthesized and structurally characterized. Amphiphilic monomers are functionalized with polydentate chelating agent (such as DOTA, DTPA and DTPAGlu) able to coordinate radioactive or paramagnetic metals for diagnostic applications, or with bioactive molecules able to recognize the cellular target. These molecules are able to auto assemble or to aggregate in mixed micelles or liposomes in aqueous solution.
All monomers were synthesized in solid-phase following an Fmoc strategy. The aggregates formulated are investigated by physical chemical methods like Small Angle Neutron Scattering (SANS) and Dynamic Light Scattering (DLS), relaxivity measurement and spectroscopy techniques (fluorescence and UV-Vis). These studies have allowed selecting the best systems for shape and size with relation to relaxivity parameters and aggregation stability. To validate the specificity and the citotoxicity of the delivery systems in vitro and in vivo studies were also performed.
The monomers containing the chelating agent, (C18)2DOTA, (C18)2DTPA and (C18)2DTPAGlu are able to auto assemble. Moreover in mixed aggregates they showed to drive the aggregation process. Aggregates fuctionalized with octreotide were investigated as promising target-selective contrast agent for MRI (Magnetic Resonance Imaging). The high relaxivity values, associated with the supramolecular aggregates, confirm the obtainment of a more rigid contrast agent able to carry numerous gadolinium ions on target cells.
In vitro binding assays on bombesin labeled liposomes allowed to select (C18)2DOTA/(C18)2-L5-bombesin as the lead compound. In these supramolecular aggregate, the peptidic monomer contains the more appropriate spacer of the length between the peptide and the hydrophobic moiety. In vivo studies confirmed the specificity towards to the receptor of the bombesin labeled liposome with respect to the liposome exposing a scrambled peptide sequence.Aggregates fuctionalized with CCK8 peptide were investigated as target-selective drug delivery systems.
The drug delivery of chemioterapeutics (i.e. doxorubicin) was studied on A431 cells overexpressing CCK receptors. The loading and release of the drug were carried out in (C18)2DOTA/(C18)2-L5-CCK8 liposome. The results obtained show the specificity and the efficacy of the system on cellular target, compared with control aggregate. In conclusion this research has permitted the achievement of new supramolecular systems containing a bioactive molecule and a chelating agent able to target tumor cells, as possible of diagnostic and therapeutic
Localisation d'in insulinome bénin par imagerie des récepteurs du glucagon-like peptide-1
No full textNovel octreotide dicarba-analogues with high affinity and different selectivity for somatostatin receptors
No full textA limited set of novel octreotide dicarba-analogues with non-native aromatic side chains in positions 7 and/or 10 were synthesized. Their affinity toward the ssts1-5 was determined. Derivative 4 exhibited a pan-somatostatin activity, except sst4, and derivative 8 exhibited high affinity and selectivity toward sst5. Actually, compound 8 has similar sst5 affinity (IC50 4.9 nM) to SRIF-28 and octreotide. Structure-activity relationships suggest that the Z geometry of the double-bond bridge is that preferred by the receptors. The NMR study on the conformations of these compounds in SDS(-d25) micelles solution shows that all these analogues have the pharmacophore beta-turn spanning Xaa7-D-Trp8-Lys9-Yaa10 residues. Notably, the correlation between conformation families and affinity data strongly indicates that the sst5 selectivity is favored by a helical conformation involving the C-terminus triad, while a pan-SRIF mimic activity is based mainly on a conformational equilibrium between extended and folded conformational states
Synthesis and characterization of DOTA-coupled dimeric Y1 receptors antagonists for breast cancer targeting
No full textPerancangan Sistem Informasi Pengelola Barang/Inventaris Di Jc Komp
No full textInventory information system is a system used to enter inventory data into the database, so that there are no errors in input, output data, and reporting based on the desired data. based on surveys and interviews with jc comp personnel, information was obtained that the existing system in the jc comp warehouse section is still manual. therefore, the system that will be created by the author is the result of a replication of the existing system in the jc comp warehouse section. in addition to the process of input and output of goods, this information system is also equipped with features for creating data reports, input and output of goods, and searching for goods data by item name. with the inventory information system is expected to be useful for the warehouse parts jc comp. By implementing this system in the jc comp warehouse, it is hoped that it can reduce errors that may occur. this system is also expected to further speed up the process of input, output, and report generation, which in turn will help the jc comp warehouseSistem Informasi Persediaan Barang adalah sebuah sistem yang digunakan untuk memasukkan data-data persediaan barang ke dalam database, sehinggga tidak terjadi kesalahan dalam input, output data, dan pembuatan laporan berdasarkan data yang diinginkan. Berdasarkan survey dan wawancara dengan bagian personalia Jc Komp, didapatkan informasi bahwa sistem yang ada dibagian gudang Jc Komp masih manual. Oleh karena itu, sistem yang akan dibuat oleh penulis adalah hasil replikasi dari sistem yang telah ada dibagian gudang Jc Comp. Selain proses input dan output barang, pada sistem informasi ini juga dilengkapi fitur pembuatan laporan data, input, dan output barang, dan pencarian data barang berdasarkan nama barang. Dengan adanya Sistem Informasi persediaan barang ini diharapkan dapat bermanfaat bagi bagian gudang Jc Komp. Dengan diterapkannya sistem ini pada bagian gudang Jc Comp, maka diharapkan dapat mengurangi kesalahan-kesalahan yang mungkin terjadi. Sistem ini juga diharapkan dapat lebih mempercepat proses input, output, dan pembuatan laporan yang pada akhirnya dapat membantu bagian gudang Jc Komp
Nuklearmedizin: Neue nuklearmedizinische Bildgebung zur Lokalisation von okkulten Insulinomen
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