Abstract: The invention relates to diethylenetriaminepentaacetic acid monoamide derivatives, their complexes and complex salts, containing gadolinium, dysprosium, iron or manganese, pharmaceutical agents containing these compounds, their use as contrast media and process for their production.

Abstract: There is provided a method for making a polyvalent inorganic anion-intercalated hydrotalcite-like material by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free, aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a polyvalent inorganic anion, in its acid, acid salt or ammonium salt form, to make a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a borate- metatungstate- and paramolybdate-intercalated hydrotalcite-like material.

Abstract: There is provided a method for making a divalent inorganic anion-intercalated hydrotalcite-like material by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a divalent inorganic anion, in its acid, acid salt or ammonium salt form, to make a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a sulfate- and metavanadate-intercalated hydrotalcite-like material.

Abstract: There is provided an improved method for making synthetic hydrotalcite by first reacting a divalent metal compound with a trivalent metal oxide powder in a carboxylic acid-free, aqueous solution or suspension to form an intermediate. This intermediate is then contacted with an anion source such as carbon dioxide; a carbonate-containing compound; an acid or an ammonium salt to form a layered double hydroxide having the formula:A.sub.1-x B.sub.x (OH).sub.2 C.sub.z.mH.sub.2 O, where A represents a divalent metal cation, B represents a trivalent metal cation, C represents a mono- to polyvalent anion, and x, z and m satisfy the following conditions: 0.09<x<0.67; z=x/n, where n=the charge on the anion; and 2>m>0.5. Said layered double hydroxide is typically separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means.

Abstract: There is provided a method for making monovalent organic anion-intercalated hydrotalcite-like materials by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free, aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a monovalent organic anion to form a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a stearate-, acetate- or benzoate-intercalated hydrotalcite-like material.

Abstract: There is provided an improved method for making synthetic hydrotalcite by first reacting powdered magnesium oxide with a high surface area, transition alumina in a solution or suspension to form a meixnerite-like intermediate. This intermediate is then contacted with an anion source such as an acid, and most preferably carbon dioxide, to form the layered double hydroxide which is separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means. On a preferred basis, the transition alumina combined with activated magnesia consists essentially of an rehydratable alumina powder having a surface area of 100 m.sup.2 /g or greater. To make related double hydroxide compounds, still other reactants such as bromides, chlorides, boric acids, or salts thereof, may be substituted for the carbon dioxide gas fed into this suspension.

Abstract: The present invention relates to metabolically labile esters, and to contrast media for X-ray and magnetic resonance imaging comprising these esters. The esters have formula (I): ##STR1## in which R.sup.3 is asteroid residue. The esters contain at least one iodine atom and/or heavy metal atom. The compound are metabolizable to products which are soluble in body fluids and are physiologically acceptable.

Abstract: Stable colloidal dispersions, in water, of rare earth compounds, e.g., yttric rare earth compounds, are produced by (a) reacting, in an aqueous reaction medium, a rare earth oxide with a controlled effective amount of a monovalent water-soluble acid having a pK.sub.a of from 2.5 to 5.0, and then (b) heating the resulting medium of reaction.

Abstract: A group of functionalized amine chelants having ortho ligating functionality that form complexes with rare-earth type metal ions are disclosed. The complexes can be covalently attached to an antibody or antibody fragment and used for therapeutic and/or diagnostic purposes. In addition certain of the chelant-radionuclide complexes can be effectively employed in compositions useful as therapeutic and/or diagnostic agents for calcific tumors and/or relief of bone pain.

Abstract: The present invention provides a gadolinium-DTPA complex containing a carborane unit having structural formula (1) given below and an intermediate thereof, i.e., carborane-containing DTPA derivative represented by formula (2) given below. ##STR1## The present invention also provides a method of synthesizing the compound (1), which comprises reacting an ester derivative of DTPA with a carborane derivative in the presence of a palladium catalyst, deesterifying by treatment with an acid, reacting with gadolinium trichloride hexahydrate, and treating with an alkali to give the desired compound (1).

Abstract: A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

Abstract: A group of functionalized amine chelants having ortho ligating functionality that form complexes with rare-earth type metal ions are disclosed. The complexes can be covalently attached to an antibody or antibody fragment and used for therapeutic and/or diagnostic purposes. In addition certain of the chelant-radionuclide complexes can be effectively employed in compositions useful as therapeutic and/or diagnostic agents for calcific tumors and/or relief of bone pain.

Abstract: Compounds of a general Formula I ##STR1## wherein Z.sup.1 and Z.sup.2 in each case independently mean the residue--(CH.sub.2).sub.m --(C.sub.6 H.sub.4).sub.q --(O).sub.k --(CH.sub.2).sub.n --(C.sub.6 H.sub.4).sub.1 --(O).sub.r --R,whereinm and n means the numbers 0-20, k, l, q and r means the numbers 0 and 1, andR means a hydrogen atom, an optionallyOR.sup.1 -substituted C.sub.1 -C.sub.6 -alkyl residue, or aCH.sub.2 COOR.sup.1 group with R.sup.1 meaning a hydrogen atom,a C.sub.1 -C.sub.6 -alkyl residue, or a benzyl group,X means a hydrogen atom and/or a metal ion equivalent of an element of atomic number 21-29, 42, 44 or 57-83,with the provisos that at least two the substituents X stand for a metal ion equivalent; that one of the substituents Z.sup.1 and Z.sup.2 stands for a hydrogen and the other is not H; that--if n and 1 each mean the number 0--k and r do not simultaneously mean the number 1; that--(O).sub.r --R is not --OH; and that Z.sup.1 and Z.sup.2 are not --CH.sub.2 --C.sub.6 H.sub.4 --O--CH.sub.

Abstract: The invention relates to new dimeric DTPA derivatives, their metal complexes, containing at least one ion of an element of atomic numbers 21-32, 37-39, 42-51 and 57-83, agents containing these complexes, their use in NMR diagnosis and/or diagnostic radiology, radiodiagnosis and radiotherapy, as well as process for their production.

Abstract: Compounds of general Formula I ##STR1## wherein R.sup.3 is a saturated, unsaturated, straight- or branched-chain or cyclic aliphatic hydrocarbon residue of up to 16 carbon atoms or, if R.sup.4 is a hydrogen atom, a cycloalkyl group or an aryl or aralkyl group optionally substituted by one or several C.sub.1 -C.sub.6 -dialkylamino groups or by one or several C.sub.1 -C.sub.6 -alkoxy groups,R.sup.4 is a hydrogen atom, a saturated, unsaturated, straight- or branched-chain or cyclic hydrocarbon residue of up to 16 carbon atoms, orR.sup.3 and R.sup.4 jointly mean a saturated or unsaturated 5- or 6-membered ring optionally substituted or containing an O, S, N atom or oxo substituent, and Y is COOX or CONR.sub.3 R.sub.4,are valuable complexing agents, complexes or complex salts, e.g., for use as NMR or X-ray diagnostic image-enhancement agents or radioactive diagnostic agents.

Abstract: 1. Compounds of general Formula I ##STR1## wherein n and m in each case mean the numbers 0, 1, 2, 3 and 4,X stands for a hydrogen atom and/or a metal ion equivalent of an element of atomic numbers 21-29, 31, 32, 37-39, 42-44, 49 or 57-83,R.sup.1 and R.sup.2, being different, mean in each case a hydrogen atom or a straight-chain, branched, saturated or unsaturated C.sub.0 -C.sub.20 -alkylene group, this alkylene group exhibiting at the end either a second molecule of general Formula I.sub.A or I.sub.

Abstract: Polymers comprising a ligand containing a carboxylic acid group, optionally at least one ion of an element of the atomic numbers 21-29, 42, 44 or 57-83 as well as optionally cations of inorganic and/or organic bases, amino acids or amino acid amides are valuable complexing agents and complexes for diagnosis.

Abstract: Polymers comprising a ligand containing a carboxylic acid group, optionally at least one ion of an element of the atomic numbers 21-29, 42, 44 or 57-83 as well as optionally cations of inorganic and/or organic bases, amino acids or amino acid amides are valuable complexing agents and complexes for diagnosis.

Abstract: Diethylenetriaminepentaacetic acid monoamide derivatives, their complexes and complex salts, containing an element of atomic numbers 21-29, 31, 32, 39, 42-44, 49 or 57-83, pharmaceutical agents containing these compounds, their use as contrast media and process for their production.

Abstract: Novel cerium (IV) oxidic compounds, well suited as catalysts, e.g., for the clean combustion of hydrocarbon fuels and for the "drying" of paint compositions, each Ce(IV) atom of which being coordinated with two anions of an organic oxyacid advantageously having a pKa greater than 1, preferably greater than 2, or a mixture of such oxyacids, and the oxidic oxygen atom or atoms of which being other than those comprising the organic oxyacids; representative such novel cerium (IV) oxidic compounds, whether yellow crystalline solids or yellow liquids, have the formula:(H.sub.2 O).sub.p ?Ceo(A).sub.2.(AH).sub.n.!.sub.min which the radicals A, which may be the same or different, are each the residue of an organic oxyacid of formula AH, p is an integer ranging from 0 to 5, n ranges from 0 to 2 and m is an integer ranging from 1 to 12.

Abstract: Porphyrin complex compounds consisting of a meso-tetraphenylporphyrin ligand of general formula I ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 have varying meanings, and an ion of an element of atomic numbers 21-32, 38, 39, 42-51 or 58-83 as well as optionally one or more physiologically harmless cation(s) of inorganic and/or organic bases, amino acids or amino acid amides are valuable diagnostic agents.

Abstract: Metal complexes containing a metal of atomic numbers 39-42, 44-51 or 56-83 and a complexing agent can be used for the production of contrast media for use in the contrast-enhanced computer tomography of the liver and the biliary tracts.

Abstract: Particulate and coarse ammonium rare earth double oxalate crystals, readily converted into rare earth oxide particles by simple calcination, e.g., yttrium oxide particles, are prepared by (a) intimately admixing, in an aqueous medium, (i) at least one rare earth neutral oxalate with (ii) at least one precursor compound adapted to liberate ammonium ions in water and (iii) at least one precursor compound adapted to liberate oxalate ions in water, (b) separating the double oxalate precipitate thus formed, and (c), optionally, washing and drying such double oxalate precipitate.

Abstract: Novel compounds of the formula ##STR1## where G.sup.1 and G.sup.2 are each independently --OH or --N(R.sup.2).sub.2, provided that at least one of G.sup.1 and G.sup.2 is --N(R.sup.2).sub.2, where each R.sup.2 is independently hydrogen, alkyl, aryl, acyl or --(A).sub.p --R.sup.a and the other variables are as defined in the specification and claims, and novel complexes of these compounds with metals are useful in diagnostic and therapeutic methods.

Abstract: Particulate ammonium rare earth double oxalate crystals, homogeneous in particle size and having a narrow particle size distribution and readily converted into rare earth oxide particles by simple calcination, e.g., yttrium oxide particles, are prepared by (a) intimately admixing, in an aqueous medium, (i) at least one precursor compound adapted to liberate oxalate ions in aqueous solution with (ii) at least one water-soluble rare earth compound and (iii) at least one ammonium salt, (b) separating the double oxalate precipitate thus formed, and (c), optionally, washing and drying such double oxalate precipitate.

Abstract: Novel compounds containing a polyiodinated aromatic or heteroaromatic residue and their chelate complexes with ions of metal elements with atomic number from 20 to 31, 39, from 42 to 44, 49 and from 57 to 83, and their salts with physiologically tolerable organic and inorganic bases are useful contrast agents for preparation of diagnostic formulations to obtain images of organs and/or tissues of human and animal body through the use of nuclear magnetic resonance or X-rays or the combination of both nuclear magnetic resonance and X-rays.

Abstract: Novel compounds obtainable by reacting together an imido-reagent such as diphenylphosphonimido-triphenylphosphorane), or a phosphine oxide such as p-tolyldiphenylphosphine oxide, with a chelate of a transition or lanthanide or actinide metal, such as tris(dibenzoylmethide)europium III, have the property of fluorescing in UV radiation. The invention includes solid polymer bodies containing such compounds, or chelates of transition or lanthanide or actinide metals generally, the bodies having the property of emitting light or infra-red radiation when subjected to a flux of ultra-violet or ionising radiation by virtue of internally generated, e.g. by tritium ionising radiation. The body is preferably of polystyrene formed by polymerising the monomer in the presence of the compound or metal chelate.

Abstract: The present invention relates particularly to novel preorganized hexadentate ligands that are suitable for complexing with a radionuclide, and are useful as general imaging agents for diagnostic purposes.

Abstract: A diagnostic medium contains at least one physiologically well tolerated complex salt comprising an anion of a complexing acid and one or more central ion or ions of an element with an atomic number of 21 to 29, 42, 44 or 57 to 83 and, optionally, one or more physiologically biocompatible cation or cations of an inorganic and/or organic base or amino acid, optionally, with additives customary in galenic formulations, dissolved or suspended in an aqueous medium.

Abstract: Novel metal-organic microporous materials are prepared in solution using mild reaction conditions from a metal or metalloid ion with a ligand containing multidentate functional groups in the presence of a templating agent. The resultant microporous materials are useful in the purification of liquids and gases.

Abstract: The invention relates to ligands having the formula (I), in which X represents a heterocyclic group, together with the process for their preparation. The invention also concerns mono- or polymetallic complexes formed by said ligands with metallic ions selected from lanthanide ions, transition metal ions, barium ion, bismuth ion, lead ion and the radioisotopes 99m.sub.Tc, 111.sub.In, 90.sub.Y, 64.sub.Cu and 169.sub.Yb, as well as salts physiologically acceptable to these complexes. The salts of said complexes can be used as diagnostic and therapeutic agents in magnetic resonance imaging, radiology, in vivo chemical displacement agents and in nuclear medicine.

Abstract: Disclosed is a method for the preparation of particles of a rare earth ammonium double oxalate by mixing a first aqueous solution of ammonium oxalate and a second aqueous solution of a water-soluble rare earth salt. The double oxalate particles have a polyhedral particle configuration with a uniform particle size distribution, from which a rare earth oxide powder of a polyhedral particle configuration with good flowability can be obtained by calcination, when the first and second aqueous solutions are prepared under exact control of the concentrations of the respective ionic species and the aqueous slurry containing the precipitates of the double oxalate is subjected to an aging treatment during which changes take place in the particle morphology and in the crystallographic structure of the double oxalate particles.

Abstract: Novel organic compounds and metal ion-containing amino acid chelates are described which are useful in solid phase synthesis of polypeptides and as magnetic resonance imaging (MRI) enhancing agents. The present invention also relates to a convenient and straightforward method to synthesize a metal-ligating amino acid suitable as MRI enhancing agents or for introducing a strong metal binding site at any chosen position in a peptide. Some compounds are designed to be compatible with N-.alpha.-Fmoc peptide synthesis strategy, and can easily be prepared on large scale. Thus, flexible linkers of different lengths and containing various structures can be placed between the .alpha.-carbon backbone of peptides and metal binding moieties. These peptides will provide a variety of affinity cleaving reagents which can be directed against protein or nucleic acid targets. Therefore, these molecules can serve as an important tool to study protein folding, protein-protein and protein-nucleic acid interactions.

Abstract: A corrosion inhibited fuel mixture includes a hydrocarbon fuel, at least one vanadium composition, and a yttrium composition. The concentration of the yttrium composition in the mixture provides at least a stoichiometric amount of yttrium for a substantially complete reaction between the yttrium and V.sub.2 O.sub.5 formed from the vanadium composition when the mixture is burned. The yttrium and V.sub.2 O.sub.5 react to form YVO.sub.4. One particular yttrium composition useful as a hydrocarbon fuel soluble, water stable vanadium corrosion inhibitor incorporates a yttrium ester having at least four carbon atoms and a hydrocarbon fuel soluble chelating agent that includes 2,4-pentanediene. The complex has a molar ratio of 2,4-pentanediene to yttrium of up to 5:1.

Abstract: The peptides described are modified with the phosphine group and are useful for marking with .sup.99m Tc and .sup.186-188 Re or paramagnetic agents for use in diagnosis and radiotherapy; in particular chelating compounds having the co-ordinating sets PN.sub.2 X, where X is --S, --O, COO--, PN.sub.3, P.sub.2 N.sub.3 and P.sub.2 N.sub.2 are described.

Abstract: The invention is directed to a method of incorporating expanded porphyrins, and particularly of incorporating a sapphyrin or a texaphyrin, before, during, or after chemical synthesis of an oligomer to form an expanded porphyrin-oligonucleotide conjugate, and particularly a sapphyrin- or texaphyrin-oligonucleotide conjugate. This method includes reacting derivatized nucleotides and a sapphyrin or a texaphyrin in a desired order in an automated or manual DNA synthesizer having a solid support to form a sapphyrin- or a texaphyrin-oligonucleotide conjugate.

Abstract: Novel complexes of paramagnetic ions and compounds bearing long acyl chains have been synthesized as magnetic resonance imaging contrast agents. These novel liposoluble contrast agents may be administered alone, or with lipids, suspending agents or other additives. The lipids may be in the form of liposomes, micelles or lipid emulsions. The contrast agents of the invention have particular use in magnetic resonance imaging of the liver, blood pool and reticuloendothelial system.

Abstract: An article suitable for use as a biosensor includes a species of a formula X--R--Ch adhered to a surface of the article as part of a self-assembled monolayer. X is a functionality that adheres to the surface, R is a spacer moiety, and Ch is a chelating agent. A metal ion can be coordinated by the chelating agent, and a polyamino acid-tagged biological binding partner of a target biological molecule coordinated to the metal ion. A method of the invention involves bringing the article into contact with a medium containing or suspected of containing the target biological molecule and allowing the biological molecule to biologically bind to the binding partner. The article is useful particularly as a surface plasmon resonance chip.

Abstract: The present invention provides new and structurally diverse compositions comprising compounds of the general formula: ##STR1## Wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are the same or different and are --CO--(CH.sub.2).sub.y --SH, --(CH.sub.2).sub.2 --SH, --SO.sub.2 --(SH.sub.2).sub.t --SH,--SH,--(CH.sub.2).sub.q --COOH, and --(CH.sub.2).sub.v --CONR.sup.6 R.sup.7, provided at least one of R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 is a sulfur containing moiety; n is 0 to about 10; i is 2 to about 5; j is 2 to about 5; y is 1 to about 5; z is 1 to about 6; t is 1 to about 5; q is 1 to about 5; v is 1 to about 5; R.sup.6 is H, alkyl, hydroxyalkyl, polyhydroxyalkyl, arylalkyl or alkoxyalkyl; R.sup.7 is H, alkyl, hydroxyalkyl, polyhydroxyalkyl, arylalkyl or alkoxyalkyl; and R.sup.7 can be polyamine when R.sup.6 is H.Methods for imaging using compositions of the invention are also provided.

Abstract: The invention features a method of blood pool imaging which utilizes an imaging agent which can be easily labelled with a radioactive isotope and injected into a patient. The imaging agent is a covalent conjugate of a polymeric carrier, protective groups, and chelating groups. The imaging agent is preferably provided in the form of a blood pool imaging composition, which includes an imaging agent of the invention, a buffer and a reducing compound. A radioactive isotope is added to the blood pool imaging composition to label the imaging agent, and the composition containing the labelled imaging agent is injected intravenously into a patient.

Abstract: Metal-containing steroid mimic complexes are provided. Compositions containing a metal ion incorporated into a steroid skeleton structure and ligands useful in the preparation of such compositions are also provided. The metal ion is preferably a radionuclide, such as technetium, rhenium or gallium. Methods for using the metal complexes for diagnostic and therapeutic purposes are further provided.

Abstract: The invention relates to catalysts for the synthesis of .beta.-hydroxy carbonyl compounds, and in particular to enantioselective catalysts.

Abstract: Heterocyclic chelating agents and salts thereof of formula I: ##STR1## wherein X represents a bond, O or S, or a group CHR.sup.1 or NR.sup.3 ; each R.sup.1 represents H, a group OR.sup.3 or NR.sup.3 R.sup.3, or an alkyl or alkoxyalkyl group optionally substituted by a hydroxyl group or by a group NR.sup.3 R.sup.3 or CON.sup.3 R.sup.3 ;each R.sup.2 represents H, or an alkyl or alkoxy group optionally substituted by a hydroxyl or alkoxy group;each R.sup.3 represents H, an optionally hydroxylated alkyl group or a group CH.sub.2 Y;Y represents a group COZ, CON(OH)R.sup.4, POZ.sub.2 or SO.sub.2 Z,Z represents a group OR.sup.4, NR.sup.4 R.sup.4 or ##STR2## where each R.sup.11 is H, a hydroxyl group or an optionally hydroxylated alkyl group, s is 0, 1 or 2, and W is CHR.sup.11, NR.sup.11 or an oxygen atom; andeach R.sup.4 represents H, or an optionally mono- or poly-hydroxylated alkyl, alkoxyalkyl or polyalkoxyalkyl group;with the provisos that where s is 0 then W is CHR.sup.

Abstract: Texaphyrins are provided for use as radiation sensitizers. Advantageous properties of texaphyrins for use as a radiation sensitizer include: i) a low redox potential which allows radiation-induced hydrated electrons to flow to texaphyrin rather than neutralizing hydroxyl radicals, allowing hydroxyl radicals to cause cellular damage, ii) a relatively stable texaphyrin radical that reacts readily to covalently modify neighboring molecules causing further cellular damage, iii) intrinsic biolocalization, and iv) indifference to the presence or absence of O.sub.2. These properties allow texaphyrins to be particularly effective for treating the hypoxic areas of solid neoplasms. Methods of treatment for an individual having a neoplasm or atheroma include the use of a texaphyrin as a radiation sensitizer and as an agent for photodynamic tumor therapy, or the use of a texaphyrin for internal and for external ionizing radiation. Novel texaphyrins are provided.

Abstract: Families of Diels Alder adducts and of metal complexes of Diels Alder adducts, which are useful as particularly active compounds for use in photodynamic therapy, are disclosed. The Diels Alder adducts and a preferred family of metal complexes have the structures of Formulas 1, 2, 3 and 4, below: ##STR1## where R1, R2, R3 and R4 can be the same or different, and each is methyl, ethyl or an amino acid moiety which is a part of an amide produced by reaction between an amine function of a naturally occurring amino acid and a carbonyl function of the adduct, R5, R6 and R7 can be the same or different, and each is ethyl or an amino acid moiety which is a part of an amide produced by reaction between an amine function of a naturally occurring amino acid and a carbonyl function of the adduct.

Abstract: Paramagnetic metal complexes of 1-(p-n-butylbenzyl)diethylenetriamine pentaacetic acid and pharmaceutically acceptable salts thereof are effective as tissue-specific MRI contrast agents, and in particular as hepatobiliary MRI contrast agents.

Abstract: A novel bifunctional macrocyclic chelating agent useful for attaching metal ions to proteins, polypeptides and other polymers. These reagents are unique in their ability to bind a variety of metal ions and to yield a high metal ion concentration per protein molecule. Protein metal chelates thus obtained will have useful radiophysical, chemical, fluorescent, photochemical and magnetic properties suitable for biomedical applications.

Abstract: In accordance with this invention, there is provided a polymer comprising units comprising the residue of a chelating agent linked to a poly(alkylene oxide) moiety, and a method for the preparation thereof. The polymer is particularly useful in therapeutic and diagnostic imaging compositions and as an antistatic agent.

Abstract: Texaphyrins are provided for use as radiation sensitizers. Advantageous properties of texaphyrins for use as a radiation sensitizer include: i) a low redox potential which allows radiation-induced hydrated electrons to flow to texaphyrin rather than neutralizing hydroxyl radicals, allowing hydroxyl radicals to cause cellular damage, ii) a relatively stable texaphyrin radical that reacts readily to covalently modify neighboring molecules causing further cellular damage, iii) intrinsic biolocalization, and iv) indifference to the presence or absence of O.sub.2. These properties allow texaphyrins to be particularly effective for treating the hypoxic areas of solid neoplasms. Methods of treatment for an individual having a neoplasm or atheroma include the use of a texaphyrin as a radiation sensitizer and as an agent for photodynamic tumor therapy, or the use of a texaphyrin for internal and for external ionizing radiation. Novel texaphyrins are provided.