A new fluorescence-based biosensor is presented. The biosensing scheme is based on the fact that a fluorophore in close proximity to a metal film (<100 A) experiences strong quenching of fluorescence and a dramatic reduction in the lifetime of the excited state. By immobilizing the analyte of interest (or a structural analog of the analyte) to a metal surface and exposing it to a labeled recept...

An appropriate receptor-targeted tracer for sentinel lymph node biopsy (SLNB) was prepared. We combined the fluorescence tracer (Indocyanine green, ICG) with Rituximab (a chimeric human/murine monoclonal antibody targeting the CD20 antigen on the surface of lymphocyte) directly to produce a new tracer (ICG-Rituximab). When the new tracer drains to the lymph node, Rituximab will combine with CD2...

BACKGROUND Nanoparticles have been extensively investigated for targeted delivery of anticancer drugs. Since the folate receptor is universally over-expressed on the tumor cell membrane, folic acid is often used to modify the fate of nanoparticles in biologicals. METHODS To fabricate targetable nanoparticles, folic acid was conjugated to a pullulan backbone and poly(DL-lactide-co-glycolide) (...

A stochastic model is described that predicts the degree of singlet/singlet energy transfer in complexes formed between monovalent ligands and monovalent receptors. The modeling approach is intended to serve as an analytical tool for approximating the level of fluorescence quenching that can be expected to occur in fluorescently labeled monovalent ligands and receptors that are bound together i...

The nature of the problem Some experimental evidence Mechanisms for G protein-coupled receptors Which equillibrium constants tell us about the binding sites? Limitations of ternary complex mechanisms What is known about the conformation of the receptor? Fusion of the receptor and G protein What is known about the conformations of the receptor? Fluorescence changes How many receptor conformation...

The thermodynamics of ligand-receptor interactions at the surface of living cells represents a fundamental aspect of G protein-coupled receptor (GPCR) biology; thus, its detailed elucidation constitutes a challenge for modern pharmacology. Interestingly, fluorescent ligands have been developed for a variety of GPCRs in order to monitor ligand-receptor binding in living cells. Accordingly, new m...

A univalent and bioactive fluorescent derivative of histamine bound to the surface of human polymorphonuclear leukocytes; free histamine was found to compete with this derivative for binding sites. Histamine H2-receptor specificity was indicated by binding inhibition experiments using cimetidine (H2-specific) but not diphenhydramine (H1-specific). Video-intensification fluorescence microscopy w...

Purpose: To study the protective effect of oxytocin on hypoxic-ischemic brain neuron injury in neonatal rats, and mechanism action involved.Methods: Hippocampal slices from SD rats were cultured oxygen/glucose-deprived (OGD) solution, leading to establishment model hippocampal vitro. The assigned 3 groups: control (ACSF solution), (OGD solution + 1 μM oxytocin). vertebral neurons CA1 region HIB...

Long-range cellular communication between the sperm and egg is critical for external fertilization. Sperm-activating peptides (SAPs) are diffusible components of the outer layer of eggs in echinoderms, and function as chemoattractants for spermatozoa. The decapeptide named speract is the best-characterized sea urchin SAP. Biochemical and physiological actions of speract have been studied with p...