Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety of macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates of these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages of these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: This invention relates to a method of directing a therapeutic agent to selected cells, wherein a complex is formed between a polysaccharide capable of interacting with a cell receptor and a therapeutic agent. The resulting complex is administered to a subject, and permitted to be internalized into the selected cells through a process known as receptor mediated endocytosis (RME). The polysaccharide may be, for example, arabinogalactan, gum arabic, mannan or hydrolysis products thereof; the therapeutic agent may be, for example, an antiviral agent, a nucleic acid, hormone, steroid, antibody, chemoprotective or radioprotective agent. The cell receptor may be for example, the asialoglycoprotein receptor or the mannose receptor.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages or these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: The preparation and isolation of biodegradable superparamagnetic MR imaging contrast agents for the vascular compartment is described. These aggregates are comprised of individual biodegradable superparamagnetic metal oxide crystals which aggregates have an overall mean diameter less than about 4000 angstroms. The preferred vascular imaging contrast agent is comprised of aggregates of iron oxide crystals having an overall mean diameter less than about 500 angstroms. These contrast agents may be associated with a macromolecular species, which assist, among other things, in the preparation of these extremely small materials, and may be dispersed or dissolved in a physiologically acceptable medium. Preferred media also stabilize the materials against further aggregation even under harsh sterilization conditions.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety of macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates of these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages of these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: A new ligand binding assay is based upon measurements of relaxation rates of the solvent, which are obtained with a magnetic resonance (MR) spectrometer. It is termed a solvent mediated relaxation assay system (SMRAS). SMRAS is based on the observation that the enhancement of proton relaxation rates produced by a magnetic material can be modulated by the binding of various analytes to a magnetic material. Hence the relaxation rate of the solvent can be interpreted to give information on the concentration of an analyte.

Abstract: A new ligand binding assay is based upon measurements of relaxation rates of the solvent, which are obtained with a magnetic resonance (MR) spectrometer. It is termed a solvent mediated relaxation assay system (SMRAS). SMRAS is based on the observation that the enhancement of proton relaxation rates produced by a magnetic material can be modulated by the binding of various analytes to a magnetic material. Hence the relaxation rate of the solvent can be interpreted to give information on the concentration of an analyte.

Abstract: The preparation and isolation of biodegradable superparamagnetic MR imaging contrast agents for the vascular compartment is described. These aggregates are comprised of individual biodegradable superparamagnetic metal oxide crystals which aggregates have an overall mean diameter less than about 4000 angstroms. The preferred vascular imaging contrast agent is comprised of aggregates of iron oxide crystals having an overall mean diameter less than about 500 angstroms. These contrast agents may be associated with a macromolecular species, which assist, among other things, in the preparation of these extremely small materials, and may be dispersed or dissolved in a physiologically acceptable medium. Preferred media also stabilize the materials against further aggregation even under harsh sterilization conditions.

Abstract: Competitive protein binding radioassay for sera (or cell) vitamin B.sub.12 and/or serum folate (target components, or analytes) or other target components in liquid ambient utilizing a highly alkaline (pH 12-14) environment and reducing agent for denaturing separating the target component(s) from serum without boiling, consistent with other requirements of such assays, then reducing pH to an 8-10 range for effecting the competitive protein binding after which protein bound and unbound groups of radioactively tagged replicates of the target component(s) can be separated and detected to determine content of the target component(s) in the original serum (or cell), i.e. original endogenous analyte(s).