Abstract: Novel compounds having the formula (II) ##STR1## where X is radioactive Se or Te, z is 0 or 1 and R is OH or an amino acid residue, particularly 23-[.sup.75 Se]-selena-25-homocholic acid and its glycine and taurine conjugate have outstandingly good properties for the investigation of bowel function.

Abstract: A smoke sensing detector for use with an indicating device comprises a chamber adapted to allow smoke to pass therethrough, an inner electrode carrying a radioactive source, a collector electrode having one or more holes and mounted on the inner electrode by insulating pillars, and an outer electrode. The collector and outer electrodes define a first ionization region, and the collector and inner electrodes define a second or reference ionizaton region which is comparatively little affected by the passage of smoke. Mounting the collector electrode on the inner electrode reduces costs, is easy and ensures that, in the event of insulation failure, the device is fail safe.

Abstract: A smoke sensing detector of the dual ionisation region type, including an inner electrode, an outer electrode, and a collector electrode mounted on the inner electrode by means of pillers of insulating material, a first ionisation region being formed by the outer electrode and the collector electrode, and a second or reference ionisation region being formed by the inner electrode and the collector electrode, wherein the collector electrode supports or incorporates a nickel-63 radioactive source emitting radiation into both ionisation regions.

Abstract: The invention relates to smoke detectors of the kind comprising first and second electrodes defining an ionization chamber permitting entry of smoke, said ionization chamber being optionally divided into two regions by a collector electrode, a radioactive source to ionize gas in the ionization chamber and a potential difference applied across the first and second electrodes to cause an ion current to flow, which current is affected by entry of smoke, and provides an auxiliary electrode positioned in the ionization chamber, and means to maintain or create a potential difference between the first electrode and the auxiliary electrode. The auxiliary electrode may be used for testing or for adjustment of sensitivity.

Abstract: An indium-111 preparation comprises a complex of indium-111 with a quinoline compound carrying an 8-hydroxyl group, e.g. oxine, present in an aqueous medium which also contains a surface active agent to prevent the complex from becoming bound to the surface of the vessel on autoclaving, and optionally a buffer to improve blood cell labelling efficiency. The surface active agent is preferably non-ionic, e.g. a polyoxyethylene sorbitan ester of a fatty acid. The buffer is preferably N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid.

Abstract: Dual isotope assays for thyroid function are performed by carrying out a radio-immunoassay for two of thyroxine (T4), tri-iodothyronine (T3), thyroid stimulating hormone (TSH), and thyroxine binding globulin (TBG) wherein a version of one of the thyroid components, preferably T4 or T3 is labelled with Selenium-75 and the version of the other thyroid component is labelled with a different radionuclide, preferably Iodine-125.

Abstract: A method of reducing the pertechnetate in TcO.sub.4.sup.- comprises mixing together an aqueous solution of pertechnetate, e.g. the eluent from a technetium generator, metallic tin or an alloy thereof as a reducing agent for the pertechnetate, and a soluble salt of a metal below tin in the electrochemical series, e.g. copper, as an activator for the tin metal reducing agent. A complexing agent for the reduced technetium or a colloid stabilizer may also be included. The pH is preferably 3 to 12. Also claimed is a closed container containing the tin reducing agent, the activator, and the complexant or colloid stabilizer if used, preferably in a freeze-dried sterile state, to which the pertechnetate solution may be added.

Abstract: A closed container for producing, on introduction of a solution of technetium-99m as pertechnetate, technetium in a form suitable for diagnostic scanning, contains under sterile conditions tin or a tin-containing alloy as a reducing agent for the pertechnetate and a complexant for the reduced technetium, the contents of the container being present in a dry state. In the method, the pertechnetate solution, suitably the eluate in isotonic saline from a technetium-99m generator, is added to the container and the complex recovered therefrom.

Abstract: Novel Selenium derivatives of thyroxine and tri-iodothyronine have the formula: ##STR1## wherein M is I or H and either (a) R.sub.1 is OH or a carboxyl protecting group and R.sub.2 contains at least one Se, preferably .sup.75 Se, atom or (b) R.sub.2 is H or an amino protecting group and R.sub.1 contains at least one Se, preferably .sup.75 Se, atom.The compounds are useful in dual isotope assays of thyroid function.

Abstract: A method for assaying unconjugated oestriol in serum by radioimmunoassay is characterized by incorporating progesterone in the incubated assay mixture in an amount to substantially reduce the effect of non-specific steroid-binding proteins present in the serum.

Abstract: Body function of a mammal is investigated using a .gamma.-emitting .sup.75 Se or .sup.123m Te labelled derivative of a bile acid or bile salt. Thus bowel function may be investigated by oral administration of the labelled compound followed, after a suitable period of time, by either a whole body count or a faecal count of radioactivity. Preferred bile acids and salts are substituted either at the 19-position or in the C-17 side chain.

Abstract: The present invention provides compounds having the general formula ##STR1## wherein R is ##STR2## and A is 0 or 1,B is 0 to 4,C is 0 to 4,Z is Se or Te,R.sup.6 is --OH or an amino acid residue,R.sup.7 is hydrogen or saturated C.sub.1 to C.sub.4 alkyl group, when A is 1,R.sup.8 is hydrogen or saturated C.sub.1 to C.sub.4 alkyl group,N is 0 or 1,R.sup.2, r.sup.3, r.sup.4 and R.sup.5 are independently hydrogen or an .alpha.- or .beta.-hydroxyl group, or an oxo group,H.sup.5 is an .alpha.- or .beta.-H.The subject compounds, particularly the gamma emitting isotopes, are useful in the investigation of body functions.

Abstract: A method of making radioactively labelled vitamin B-12 by reacting .alpha.-(5,6-dimethylbenzimidazolyl)hydrogenobamide with cobaltous ion Co-57, or with another radioactive cobalt isotope. The method enables vitamin B-12 of high specific activity to be made, which is useful for in vitro and in vivo analysis.

Abstract: The invention provides a method and apparatus for preparing aqueous solutions of technetium-99m pertechnetate. In a preferred embodiment, the eluate from a technetium-99m generator is contacted with a cation-exchange resin having adsorbed thereon a cation which forms an insoluble salt with the anion of the generator eluate, whereby there is obtained an aqueous solution of the pertechnetate in water. The solution may be concentrated by adsorption of the pertechnetate on alumina, followed by desorption using a smaller volume of aqueous electrolyte.

Abstract: Folic acid and related compounds are assayed by competitive radio-assay using a selenium - 75 labelled version of folic acid as the competing compound.

Abstract: A container for radioactive counting which is essentially a tube of organic plastics material which has a radiation shield extending up to the side of the tube to a uniform height. The container has a reaction zone of from 1 to 10ml with a tapered portion towards its lower end. From 1% to 10% of the reaction zone has within the zone surrounded by the radiation shield.

Abstract: A Technetium-99m labelled tin colloid for liver scanning is made by adding Technetium-99m, as an aqueous solution of pertechnetate ion TcO.sub.4.sup.-, to a reagent comprising one part by weight of sodium, potassium or ammonium fluoride and from 0.00075 to 0.75 parts by weight of stannous tin.

Abstract: Novel selenium derivatives of steroids have the formula I, ##STR1## where X is hydrogen or acyl, Y is hydrocarbon and n is 0 or 1, preferably 0. Such compounds, labelled with selenium-75 are of use for investigating body function, particularly for imaging the adrenal glands, and are claimed superior for the purpose to the 6.beta.- and 19- iodine derivatives of cholesterol.

Abstract: A method for the radio-assay of an oestrogen in a biological fluid which method comprises causing the oestrogen to compete with a radio-iodine derivative, selected from the group consisting of the 2-iodo-, 4-iodo- and 2,4-di-iodo- derivatives of the oestrogen, for reaction with a specific reagent for the oestrogen, separating the oestrogen and iodo-oestrogen bound to the specific reagent from the unbound oestrogen and iodo-oestrogen and measuring the radioactive concentration of one or both the bound and unbound fractions of oestrogen.

Abstract: New selenium-75 labelled derivatives of cyclic nucleotides are described, which are of value in the saturation analysis of cyclic nucleotides, particularly adenosine-3', 5'-cyclic monophosphate (cyclic AMP) in body fluids.