Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.1 (cytosine deaminase)
 747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To develop a suitable suicide gene/prodrug therapy for the treatment of thyroid carcinomas, the relative therapeutic efficacy of four different suicide gene/prodrug combinations was compared in thyroid carcinomas in vitro. Herpes simplex virus thymidine kinase and ganciclovir (HSV-TK/GCV), Escherichia coli cytosine deaminase and 5-fluorocytosine (CD/5FC), E coli nitroreductase and CB1954 (NTR/CB1954), and human deoxycytidine kinase and cytosine arabinoside (dCK/AraC) were employed. The suicide genes were transduced into two thyroid carcinoma cell lines with retroviral vectors in which all the suicide genes were under the control of the same promoter. When the relative efficacy of four suicide gene/prodrugs was compared with therapeutic index and degree of bystander effect, we found a clear dissociation between these two parameters. Thus, HSV-TKIGCV demonstrated the widest therapeutic index, while CD/5FC and NTR/CB1954 showed the stronger bystander effect than HSV-TK/GCV. dCK/AraC had little efficacy. Advantages and limitations of each suicide gene/prodrug combinations are discussed.
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PMID:Treatment of thyroid carcinoma cells with four different suicide gene/prodrug combinations in vitro. 967 64

Molecular imaging is broadly defined as the characterization and measurement of biological processes in living animals, model systems, and humans at the cellular and molecular level using remote imaging detectors. One underlying premise of molecular imaging is that this emerging field is not defined by the imaging technologies that underpin acquisition of the final image per se, but rather is driven by the underlying biological questions. In practice, the choice of imaging modality and probe is usually reduced to choosing between high spatial resolution and high sensitivity to address a given biological system. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) inherently use image-enhancing agents (radiopharmaceuticals) that are synthesized at sufficiently high specific activity to enable use of tracer concentrations of the compound (picomolar to nanomolar) for detecting molecular signals while providing the desired levels of image contrast. The tracer technologies strategically provide high sensitivity for imaging small-capacity molecular systems in vivo (receptors, enzymes, transporters) at a cost of lower spatial resolution than other technologies. We review several significant PET and SPECT advances in imaging receptors (somatostatin receptor subtypes, neurotensin receptor subtypes, alpha(v)beta(3) integrin), enzymes (hexokinase, thymidine kinase), transporters (MDR1 P-glycoprotein, sodium-iodide symporter), and permeation peptides (human immunodeficiency virus type 1 (HIV-1) Tat conjugates), as well as innovative reporter gene constructs (herpes simplex virus 1 thymidine kinase, somatostatin receptor subtype 2, cytosine deaminase) for imaging gene promoter activation and repression, signal transduction pathways, and protein-protein interactions in vivo.
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PMID:Molecular imaging of gene expression and protein function in vivo with PET and SPECT. 1235 50