Search results for "Kinetic"
showing 10 items of 3064 documents
A new assay for O6-alkylguanine-DNA-alkyltransferase to determine DNA repair capacities using lambda-phage DNA as substrate.
1990
One O6-methylguanine (O6-meG) was introduced into each BamHI site of lambda-phage DNA as a substrate for the determination of the DNA repair protein O6-alkylguanine-DNA-alkyltransferase. A new assay using as the detection group 32P-labeled phosphate introduced at the 3' position of the modified nucleoside by incorporation of 32P-labeled TTP in the 3'-neighboring position proved highly sensitive: 10(-16) mol of the DNA lesion was still easily detectable. This DNA, which has greater than 1000 bp represents a good model for cellular DNA and was used as a substrate to measure the individual repair capacities for O6-meG in human lymphocytes of 20 healthy male and female donors. There were great …
Development and in vitro evaluation of new bifunctional 89Zr-chelators based on the 6-amino-1,4-diazepane scaffold for immuno-PET applications
2021
Abstract Introduction Combination of hydroxamate bearing side chains with the 6-amino-1,4-diazepane scaffold provides a promising strategy for fast and stable 89Zr-labeling of antibodies. Following this approach, we hereby present the development, labeling kinetics and in vitro complex stability of three resulting bifunctional chelator derivatives both stand-alone and coupled to a model protein in comparison to different linear deferoxamine (DFO) derivatives. Methods The novel 89Zr-chelator Hy3ADA5 was prepared via amide-coupling of separately synthesized 6-amino-1,4-diazepane-6-pentanoic acid and hydroxamate-containing side chains. Two further bifunctional derivatives were synthesized by e…
Impact of Undernutrition on the Pharmacokinetics and Pharmacodynamics of Anticancer Drugs: A Literature Review
2017
The etiology of undernourishment in cancer patients is multifactorial: tumor-related mechanisms (such as obstruction, metabolic abnormalities, and functionality changes) in addition to the influence of anticancer therapies, which can induce or worsen undernutrition. The evident role of undernutrition in cancer treatment outcomes suggests the need of considering nutritional status when evaluating anticancer drugs. In order to merge the available data and offer researchers and clinicians a global view of this phenomenon, the present manuscript reviews on a drug-by-drug basis the undernutrition-related pharmacokinetic and pharmacodynamic aspects of anticancer treatments. This review notes inte…
Desferrioxamine as an appropriate chelator for 90Nb: Comparison of its complexation properties for M-Df-Octreotide (M=Nb, Fe, Ga, Zr)
2014
The niobium-90 radioisotope ((90)Nb) holds considerable promise for use in immuno-PET, due to its decay parameters (t½ = 14.6h, positron yield=53%, Eß(+)(mean) = 0.35 MeV and Eß(+)(max) = 1.5 MeV). In particular, (90)Nb appears well suited to detect in vivo the pharmacokinetics of large targeting vectors (50-150 kDa). In order to be useful for immuno-PET chelators are required to both stabilize the radionuclide in terms of coordination chemistry and to facilitate the covalent attachment to the targeting vector. Different chelators were evaluated for this purpose in terms of radiolabelling efficiency and stability of the radiolabelled Nb(V) complex and in order to determine the most suitable…
Abstract B154: A first-in-human trial of GDC-0068: A novel, oral, ATP-competitive Akt inhibitor, demonstrates robust suppression of the Akt pathway i…
2011
Abstract GDC-0068 is a highly selective ATP-competitive small molecule that inhibits all three isoforms of Akt with IC50 values of 5 to 30 nM. GDC-0068 selectively inhibits cancer cells with activated Akt signaling (e.g. via PTEN loss or PIK3CA mutations). Patients with advanced solid tumors were treated with GDC-0068 using a 3+3 escalation design. GDC-0068 was dosed PO QD on a 21-day on, 7-day off schedule; endpoints included safety, pharmacokinetics (PK) and determination of pathway knockdown. Pharmacodynamics (PD) endpoints in surrogate tissue [platelet rich plasma (PRP)] were evaluated in all patients. In addition, at least two patients per cohort had pre- and on-treatment (day 15) tumo…
AAZTA5-squaramide ester competing with DOTA-, DTPA- and CHX-A″-DTPA-analogues: Promising tool for 177Lu-labeling of monoclonal antibodies under mild …
2021
Abstract Background Combining the advantages of both cyclic and acyclic chelator systems, AAZTA (1,4-bis(carboxymethyl)-6-[bis(carboxymethyl)]amino-6-methylperhydro-1,4-diazepine) is well suited for complexation of various diagnostic and therapeutic radiometals such as gallium-68, scandium-44 and lutetium-177 under mild conditions. Due to its specificity for primary amines and pH dependent binding properties, squaric acid (SA) represents an excellent tool for selective coupling of the appropriate chelator to different target vectors. Therefore, the aim of this study was to evaluate radiolabeling properties of the novel bifunctional AAZTA5-SA being coupled to a model antibody (bevacizumab) i…
Abstract CT109: A phase I/Ib study evaluating GDC-0077 plus fulvestrant in patients with PIK3CA-mutant, hormone receptor-positive/HER2-negative breas…
2020
Abstract Background: PIK3CA encodes the PI3K p110α subunit, and dysregulating mutations are widely seen in breast cancer (BC) and other solid tumors. GDC-0077 (G) is a potent p110α-selective inhibitor that degrades mutant p110α and demonstrates antitumor activity in PIK3CA-mutant BC xenograft models, either as a single agent, or combined with anti-estrogen therapy. From an ongoing, open-label, phase I/Ib dose-escalation study of G alone and combined with endocrine + targeted therapies (NCT03006172), we present data of G + fulvestrant (F) in postmenopausal patients (pts) with PIK3CA-mutant, hormone receptor-positive/HER2-negative BC, including a food-effect assessment on the pharmacokinetics…
Abstract CT-08: A Phase 1 study of MEHD7945A (MEHD), a first-in-class EGFR/HER3 dual action antibody, in patients (pts) with locally advanced or meta…
2012
Abstract Background Dysregulated human epidermal growth factor receptor tyrosine kinase (HER RTK) signaling is an important driver of tumor growth, metastasis, and survival. Extensive HER RTK co-expression and heterodimerization suggest that simultaneous blockade of multiple RTKs may be more effective than targeting individual RTKs, and may help prevent or delay development of resistance mechanisms. MEHD is a novel dual-action human IgG1 antibody. Each antigen-binding fragment blocks ligand binding to both EGFR and HER3, which is meant to inhibit the activity of the major ligand-dependent HER dimers in cancer. MEHD also elicits antibody-dependent cell-mediated cytotoxicity, and has single-a…
Synthesis and PET studies of [11C-cyano]letrozole (Femara®), an aromatase inhibitor drug
2009
Abstract Introduction Aromatase, a member of the cytochrome P 450 family, converts androgens such as androstenedione and testosterone into estrone and estradiol, respectively. Letrozole (1-[bis-(4-cyanophenyl)methyl]-1 H -1,2,4-triazole; Femara) is a high-affinity aromatase inhibitor ( K i =11.5 nM) that has Food and Drug Administration approval for breast cancer treatment. Here we report the synthesis of carbon-11-labeled letrozole and its assessment as a radiotracer for brain aromatase in the baboon. Methods Letrozole and its precursor (4-[(4-bromophenyl)-1 H -1,2,4-triazol-1-ylmethyl]benzonitrile) were prepared in a two-step synthesis from 4-cyanobenzyl bromide and 4-bromobenzyl bromide,…
Theoretical Study of Primary Reaction of Pseudozyma antarctica Lipase B as the Starting Point To Understand Its Promiscuity
2014
Pseudozyma antarctica lipase B (PALB) is a serine hydrolase that catalyzes the hydrolysis of carboxylic acid esters in aqueous medium but it has also shown catalytic activity for a plethora of reactions. This promiscuous activity has found widespread applications. In the present paper, the primary reaction of PALB, its native hydrolytic activity, has been studied using hybrid quantum mechanical/molecular mechanical (QM/MM) potentials. Free energy surfaces, obtained from QM/MM Molecular Dynamics (MD) simulations, show that the reaction takes place by means of a multi-step mechanism where the first step, the activation of the carbonyl group of the substrate and the nucleophilic attack of Ser1…