Search results for "Dihydroxyphenylalanine"
showing 4 items of 14 documents
High-Performance TiO2 Nanoparticle/DOPA-Polymer Composites
2014
Many natural materials are complex composites whose mechanical properties are often outstanding considering the weak constituents from which they are assembled. Nacre, made of inorganic (CaCO 3 ) and organic constituents, is a textbook example because of its strength and toughness, which are related to its hierarchical structure and its well-defi ned organic–inorganic interface. Emulating the construction principles of nacre using simple inorganic materials and polymers is essential for understanding how chemical composition and structure determine biomaterial functions. A hard multilayered nanocomposite is assembled based on alternating layers of TiO 2 nanoparticles and a 3-hydroxytyramine…
Oxidation of carbidopa by tyrosinase and its effect on murine melanoma
2009
Oxidation of the anti-Parkinsonian agent carbidopa by tyrosinase was investigated. The products of this reaction were identified as 3-(3,4-dihydroxyphenyl)-2-methylpropanoic acid and 6,7-dihydroxy-3-methylcinnoline. These results demonstrate that after oxidation of the catechol moiety to an o-quinone either a redox exchange with the hydrazine group or a cyclization reaction occur. The cyclization product underwent additional oxidation reactions leading to aromatization. The cyclization reaction is undesired in the case of hydrazine-containing anti-melanoma prodrugs and will have to be taken into account in designing such compounds. Carbidopa was tested against B16(F10) melanoma cells in cul…
The effect of nacom (L-dopa and L-carbidopa) on growth hormone secretion in 75 patients with short stature.
1977
The stimulatory effect of Nacom (250 mg L-Dopa and 25 mg L-Carbidopa) on the HGH secretion was evaluated in 75 short stature patients. The number of blood samples was restricted to only three (0, 45 and 90 min). 63 patients reached adequate HGH concentrations after the ingestion of 1 tablet Nacom (84%). Somatotropin levels increased from 2.08 (Sx 0.28) to a maximal HGH value of 14.22 (Sx 0.87) ng/ml. When the stimulatory effect of Nacom was compared with the standard method of arginine infusion in children with normal stature the arginine test was not superior to the Nacom-test. The Nacom-test appears to be a simple and reliable screening method for HGH deficiency, particularly in outpatien…
6-18F-Fluoro-l-Dihydroxyphenylalanine Positron Emission Tomography Is Superior to123I-Metaiodobenzyl-Guanidine Scintigraphy in the Detection of Extra…
2010
Context: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) may be better detected by 18F-fluorodihydroxyphenylalanine-positron emission tomography (FDOPA-PET) than 123I-metaiodobenzyl-guanidine (123-I-MIBG) scintigraphy. Objective: The objective of the study was to correlate functional imaging results with immunohistochemical, molecular-genetic, and biochemical findings. Design and Setting: Thirty consecutive patients with suspected PHEO/PGL presenting at a tertiary referral centre were investigated in a prospective study. Patients: Twenty-five patients had confirmed PHEO/PGL. Thirteen of 25 patients had a hereditary PHEO/PGL syndrome (two multiple endocrine neoplasia II, six succinate de…