Abstract: The apparatus comprises a cell 2 containing the sample 1 under investigation. Electromagnetic waves P1,P2 are applied from opposite directions and interfere with one another in the region of the cell to form a standing wave pattern 6. DUe to electrostriction effects the standing wave pattern causes particles within the sample to concentrate in certain areas in a pattern corresponding to that of the standing wave 6. This pattern of particle concentration forms a grating when seen by an input wave Pin of electromagnetic wave radiation and, provided conditions are correct, results in the generation of a phase conjugate wave Pout. Means (not shown) are provided for measuring the intensity of the phase conjugate wave Pout which gives a sensitive measure of the size of the particles suspended in the sample.

Abstract: Complexes formed between (a) an amino di- or poly-phosphonate in which phosphonate groups comprise separate carbon atoms and (b) a paramagnetic metal ion such as Gd.sup.3+, have calcified tissue seeking properties which make them useful as contrast agents for investigating bone metabolism by NMR scanning. Two preferred poly-phosphonates are ethylenediamine tetramethylphosphonate and meta-xylene-diamine tetramethylphosphonate.

Abstract: A compound having the property of selectively binding sodium ions in the presence of potassium ions and having the formula: ##STR1## where X is ##STR2## and where any aromatic ring may be substituted and/or may form part of a fused aromatic ring system.At least one of the aromatic rings may be substituted by a spectroscopic reporter group, a group which permits the compound to enter and remain in a cell and/or an electron donating or withdrawing group.A method of determining cytoplasmic sodium concentration by using this compound as a probe is also described.

Abstract: A biological sample containing an analyte, partly free and partly bound to natural binders, is incubated with a labelled specific binder for the analyte and a derivative of the analyte which does not react with the natural binders. Part of the labelled specific binder binds to the analyte derivative, the proportion depending on the free analyte concentration in the sample. The proportion is measured and used to determine the free analyte concentration. For example, the analyte may be thyroxine or cortisol, the labelled specific binder may be an antibody thereto, and the analyte derivative may be in the form of a solid matrix. The labelled specific binder should have an affinity for the analyte, expressed as a dissociation constant of the complex of the two, approximately equal to the concentration of free analyte in the sample.

Abstract: Novel propylene amine oxime ligands have the formula ##STR1## where each of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 or R.sub.8 may be hydrogen, hydrocarbon, carboxyl, amine, amide or nitrile, provided that, if R.sub.1 is the same as R.sub.9 and R.sub.2 is the same as R.sub.7, then R.sub.8 is not H. These unsymmetrical ligands form complexes with Technetium-99m which are capable, on injection into mammals, of crossing the blood-brain barrier and of being retained in the brain for a time to permit diagnosis.

Abstract: A composition for use in the preparation of a bone-scanning agent comprises a mixture of a bis-phosphonic acid of formula (I), wherein R.sup.1 and R.sup.3 may be the same or different group selected from H, --SO.sub.3 H and a lower aliphatic group which may optionally contain one or more hetero atoms and which contains at least one --SO.sub.3 H group; R.sup.2 is a group selected from H, --OH, --NH.sub.2, --NHMe, --NMe.sub.2 and lower alkyl optionally substituted by one or more polar groups; R.sup.4 is a group selected from H, --OH, --NH.sub.2 --NHMe, --NMe.sub.2, --SO.sub.3 H and a lower alkyl optionally substituted by one or more polar groups; and n is 0 or 1; with the proviso that when n is 0, R.sup.1 is not H and that when n is 1, R.sup.1 and R.sup.3 cannot both be H; or a non-toxic salt thereof, together with a reducing agent for pertechnetate ions. Technetium-99m, as an aqueous solution of pertechnetate ions, is added to the composition to form a complex of Tc-99m, and the bisphosphonate.

Abstract: A stabilizer for radioactively labelled organic compounds has the general formula ##STR1## where R is C1 to C4 alkylene which may be OH substituted, m is 0 or 1 (i.e. R may be absent or present), X is carboxyl or sulphonyl e.g. COOH or SO.sub.3 H or a salt thereof and n is 1, 2 or 3. Radiolabelled compounds of biological origin, such as nucleotides and amino acids, may be stabilized either in solution or in the freeze-dried state. For example, L-[.sup.35 S]methionine may be stabilized to prevent formation of a 47 KD band in protein transcription/translation experiments.

Abstract: A family of propylene amine oxime ligands has the formula 2 ##STR1## wherein preferably R.sup.1 is Cl-C4 alkyl or phenyl and each of R, R.sup.2, R.sup.3 and R.sup.4 is H or Cl-C4 alkyl. The technetium-99m complexes of these ligands are lipophilic neutral complexes useful as diagnostic radiopharmaceuticals and particularly for brain scanning. The ligands show stereoisomerism. The preparation and properties of the dl- and meso-stereoisomers, and of the d- and l-enantiomers, are described. The l-enantiomer and the dl-stereoisomer of the preferred compound (2, R=R.sup.1 =R.sup.2 =CH.sub.3, R.sup.3 =R.sup.4 =H) show good retention in the brain.

Abstract: A generator of radionuclides comprises a generator column (10) containing the radionuclide and provided with an inlet (12) and an outlet (14) for eluent, first and second reservoirs (16, 18) for eluent, and connecting means for passing a pre-determined column of eluent from the second reservoir through the generator column. A part defining the second reservoir, which part may be the second reservoir itself, is rotatable to determine the volume of eluent passed through the column. The second reservoir is preferably shaped as a sector of a cylinder rotatable around a horizontal axis.The generator is well suited for vacuum elution of a variable pre-determined volume of eluent into a single size collection vial with subsequent drying of the generator column.

Abstract: A method and apparatus for assaying a species in a biological sample fluid. The apparatus comprises an SAW device (1) comprising a slab (2) of piezoelectric material on the upper surface (5) of which is formed an input transducer (3) and an output transducer (4). A source of RF energy is applied to the input transducer to generate a surface acoustic wave. Applied to the surface (5) is a thin layer (8) of a material capable of binding a species to be assayed. The sample (13) to be tested is applied to the top of the layer (8). A collimated light beam (1) from a source (9) is applied to the thin film from underneath the slab (2) and is collected by a photodetector (12). When the slab (2) is energized, the vibration sets up an effective diffraction grating which is coupled to the thin film and acts to diffract the light beam (10) applied to it. The energy in the diffracted beam, as measured by the photodetector ( 12), is indicative of the progress and result of the reaction between the layer 8 and the sample.

Abstract: The invention concerns assays, such a immunoassays or two-site immunometric assays, performed using a labelled reagent and another reagent bound to magnetically attractable particles which are suspendable but insoluble in a liquid assay medium. After the labelled reagent has become partitioned between the liquid phase and the particles, in proportions which depend on the concentration of an analyte in a sample, the liquid phase is removed. Then the particles are re-suspended in another liquid medium, and the concentration of label observed. The method is particularly suitable for fluorescent and chemiluminescent' label systems, and can conveniently be performed in microtiter plates in which the wells are optically screened from one another, the observations being made from above or below the wells.

Abstract: A method for assaying complement fragment C.sub.3 a, C.sub.4 a or C.sub.5 a or the des-Arg derivative thereof in a biological sample which comprises combining equal volumes of the biological sample and a solution of 0.8 to 1.6% of an acridine derivative selected from the group consisting of acrinol, acriflavine, acriflavine hydrochloride, and aminacrine, incubating the mixture for about one minute to 2 hour at about 25.degree. C., recovering the supernatant from the resultant precipitate, incubating the supernatant with a known amount of a labeled complement fragment selected from C.sub.3 a, C.sub.4 a or C.sub.

Abstract: A method of detecting a target polynucleotide sequence in a sample uses a labelled polynucleotide secondary probe, and a polynucleotide primary probe having sequences complementary to both the target and the secondary probe. The sample, immobilized or in solution is hybridized with the primary probe; and the labelled secondary probe is also hybridized with the primary probe. The method permits the production of a labelled secondary probe which can be used in conjuction with many different primary probes for different hybridization reactions.

Abstract: A block of polymeric material 12 comprises label layers 14 and interposed non-label layers 16, each label layer containing a different known concentration of a label material. The block can be sliced by a microtome 18 into thin section each of which is useful as a standard for analysis e.g. in autoradiography. Preferred label materials are radioactive isotopes e.g. 3-H and 14-C; other label materials include metals and fluorescent materials.

Abstract: A method of performing an assay for an analyte comprises providing a chromatographic medium, preferably in sheet form, forming a reaction mixture containing a labelled reagent present partly in a form which is mobile on the medium and partly in a form which is immobile, the proportions of the two forms being related to the analyte concentration, applying the mixture to a spot on the chromatographic medium, optionally applying a solvent to cause the mobile form of the labelled reagent to migrate from the spot, and measuring the label intensity remaining at the spot. The method provides a convenient way of performing immunoassays, 2-site immunometric assays, and agglutination assays.

Abstract: A method of detecting a mutation of a specific nucleotide base in a target nucleic acid chain comprises: (a) hybridizing a labelled probe to the target to form a hybrid in which one end of the probe is positioned adjacent the specific base; (b) adding a nucleotide derivative, e.g. a thionucleotide, under conditions to cause it to join to the end of the probe if it is complementary to the specific base; (c) digesting the hybrid using an exonuclease enzyme under conditions such that the nucleotide derivative protects the probe from digestion; and observing the presence or absence of label attached to the target. The method can be used to detect mutations even when these are not present at restriction enzyme cleavage sites, and does not require the preliminary steps of restriction digestion, gel electrophoresis and DNA (or RNA) blotting.

Abstract: A packaged reagent for making Technetium-99m labelled tin colloids comprises 0.75 to 750 .mu.g stannous tin, 50 to 7000 .mu.g sodium, potassium or ammonium ion, 40 to 5000 .mu.g fluoride ion, 50 to 10,000 .mu.g of a non-toxic non-ionic surface-active agent based on poly (alkylene oxide)glycol and a container aseptically enclosing said reagent. The presence of the surface-active agent, preferably one of the Pluronic types, results in smaller sized particles being produced on addition of pertechnetate to the reagent. This results in a higher liver/spleen biodistribution ratio.

Abstract: A bone-seeking, Technetium-99m-ethylene glycol-1,2-bisphosphonate complex has been found to be useful as a bone-scanning agent. The complex, which is prepared by adding Technetium-99m, as an aqueous solution of pertechnetate, to a composition comprising a mixture of ethylene glycol-1,2-bisphosphonic acid or a non-toxic salt thereof with a reducing agent for pertechnetate, is taken up rapidly in bone to give scans of high definition and compares favorably in this and other respects to other bone-scanning agents.

Abstract: A generator of radionuclides such as technetium-99m comprises a generator column (10) containing the radionuclide, a first reservoir (16) for eluent, a second reservoir (18) to contain a volume of the eluent required for a single elution, and a vessel 40 to contain eluate. First, a pre-set volume of eluent is transferred from the first to the second reservoir; then the eluent is sucked from the second reservoir through the column into the eluate vessel. A hydrophobic filter 32 adjacent the second reservoir (18) permits the use of air to dry the column (10) and to bring the partly filled eluate vessel (40) to atmospheric pressure.

Abstract: Radiopharmaceutical compositions containing complexes of technetium-99m with a complexing agent are prone to time and activity-related decomposition and formation of pertechnetate. Stabilizing agents for such complexes are organic compounds having an amine group and a carboxylic acid group attached to an aromatic ring. A preferred stabilizing agent is the sodium salt of 4-aminobenzoic acid. There are claims to a composition comprising a technetium 99-m complex stabilized by means of the said stabilizing agent; and to a reagent which forms, on addition of an aqueous solution of pertechnetate, a radiopharmaceutical composition, which reagent comprises a tin metal or stannous reducing agent for the pertechnetate, a complexing agent for the reduced technetium, for example a phosphorus-containing bone scanning agent, and a stabilizing agent as defined.