[en] For a routine production of T₄ radioimmunoassay (RIA) kit, some complementary experiments were carried out. T₄- ¹²⁵I of relatively low specific activity was prepared by an isotope exchange method and it was used for the RIA. In paper chromatography (PC) the mixing ratios of the component of the developing solvent were controlled. Production of antibody and preparation of T₄ standards using T₄ free sera were repeated. Comparison of the assay values using reference control sera was also carried out. The results indicated that the T₄ - ¹²⁵I of low specific activity was more effective than that of high specific activity in stability point of view. The ratio of 0.5M NH₄OH:t-amOH: n-hexane = 6:5:1 (V/V) was optimum for the better resolution and reproducibility in the PC of the labelling mixtures. The T₄ antibody was produced in sufficient quantity. It could be confirmed that the human sera is more effective than the human recalcified plasma for preparing T₄ free sera or T₄ standards. By a careful calibration of T₄ standards using reference control sera, the quality-guaranteed kits could be prepared

[en] To meet the increasing demand of some popular sup(99m)Tc labelled compounds, experimental studies were carried out for the efficient preparation of instant sup(99m)Tc labelling kits such as calciumdiethylenetriaminepentaacetate (Ca-DTPA) -sup(99m)Tc (kidney and brain scanning agent), phytic acid(PA)-sup(99m)Tc (a liver scanning agent), and meso-2, 3-dimercaptosuccinic acid (DMSA)-sup(99m)Tc (a kidney scanning agent) etc. The molar ratios of the compounds to the reducing agent (SnCl₂) as well as the hydrogen ion concentration of the medium were controlled. Separation and organ distribution studies were also carried out. The results obtained were as follows: 1) Ca-DTPA... optimum molar ratio, Ca-DTPA: SnCl₂ = 10,000 : 1, pH=4, paper chromatography (PC), accumulation at kidney at 2 hrs' after intraperitoneal injection = 3% dose/g tissue, 2) PA... optimum molar ratio, PA:SnCl₂ = 1,000 : 1, pH=5, insant thin layer chromatography (ITLC), accumulation at liver at 30 minutes' post intravenous injection = 13% dose/g tissue, 3) DMSA... optimum molar ratio, DMSA:SnCl₂ = 3:1, pH=3, ITLC (acetone solvent), accumulation at kidney at 6 hours' post intravenous injection = 24% dose/g tissue

[en] For an effective preparation of o-iodohippuric acid-¹³¹I (Hippuran-¹³¹I), a useful medical tracer, kinetic studies were carried out for a lately reported high temperature isotope exchange labelling method. To acetate buffer (pH 5.5) or to absolute ethanol solvent a trace amount of sodium thiosulfate or trace hydrogen peroxide was added to proceed iodine isotope exchanges between o-iodohippuric acid (OIH) and radioiodide (¹²⁵I^-) or between OIH and molecular radioiodine (¹²⁵I₂), respectively at two different temperatures. Rate constants and activation parameters were measured by applying a radiopaper chromatographical separation technique. Since o-iodobenzoic acid (OIB) is known as a by-product often identified in the exchange labelling of OIH, data were also obtained for the isotope exchanges in OIB and iodide systems for comparison. The rate constant order was OIB reversible ¹²⁵I^->OIB reversible ¹²⁵I₂>OIH reversible ¹²⁵I^->OIH reversible ¹²⁵I₂, and the activation parameters for OIH were generally larger than those of OIB, (ΔH unequal sub(OIH) >ΔH unequal sub(OIB), ΔS unequal sub(OIH) >ΔS unequal sub(OIB)). Other data such as rate constants under different reaction conditions, solvent effects and activation parameters indicated that the mechanism of iodine isotope exchange between OIH and ¹²⁵I^- is predominantly nucleophilic even though electrophilic character can also be involved depending upon reaction conditions. Such a fact may well be caused by a feasible formation of hydrogen bonding type transition state due probably to the ortho substituent effect of CONHCH₂COOH

[en] To improve the recently developed thyroid hormone radioimmunoassay (RIA) kits, a study on immobilization of T₃ antibodies on inner wall of polystyrene tubes has been carried out. Into a series of polystyrene tubes, a constant volume of alkaline glutaraldehyde solution was added to obtain glutaraldehyde coated tubes by self-polymerization. The tubes were then treated with dilute T₃ antibody solution to react the aldehyde residues on the wall-surface with the amino groups in antibodies. Reaction parameters such as temperature, volume of the glutaraldehyde solution, pH, dilution ratio and temperature of the antibody solution, etc. were controlled. After a definite time, the excess antibody solution was decanted, and tubes were washed with plenty of barbital buffer solution. The resulting antibody coated tubes were tested with antigen bindings to verify the validity in RIA use; To the tubes, T₃-¹²⁵I of high specific activity and barbital buffer containing 8-anilino-1-naphthalene sulfonic acid (ANSA) were added and incubated with or without T₃ standard doses at room temperature. Percentage of the antibody bound radioactivity (B) to the total radioactivity (T) was calculated. The average range of B/T(%) under standard T₃ dose of upto 4 ng/ml was 35-55. The results indicated that the antibody coated tubes are applicable for the solid phase T₃ RIA under a cautious control of accuracy keeping relatively long incubation time. However, an increased amount of the immobilized antibody is further desirable to shorten the incubation time and to increase the assay sensitivity. (Author)

[en] Thyroxine T₄ radioimmunoassay (RIA) kit has already been developed in this laboratory. For an efficient diagnosis of thyroid disease, however, it is well known that the T₃ RIA should also be carried out in addition to the T₄ RIA. Accordingly, the development of T₃ RIA kit was urgently desired to match the T₄ kit and to hold a sound domestic supply systems. The high specific activity T₃¹²⁵I about 3,000 μCi/μg T₃) could be obtained by radioiodinating T₂ with chloramine-T, and the labelled product could be stahilized. In the preparation of T₃ free serum, charcoal was eliminated easily from serum by high speed centrifugation, and the resulting T₃ free serum was used for the preparation of T₃ standard serum solutions. RIA buffer system could be improved with the use of 0.025M barbital buffer, pH 8.2, containing 0.1% BSA, 0.5% bovine aamma globulin and 0.02% merthiolate. Antibody titer was increased threefold by using the 0.025M barbital buffer; the titer was 8,000: 1 in the 0.078M borbital buffer, pH 8.6, containing 0.1% BSA and 0.1% NaN₃ while it was 26,000 : 1 in the above described 0.025M barbital buffer. The modified buffer system was also efficient for the use in T₄ RIA since it increased the T₄ antibody titer twofold. When the same buffer system was used in T₃ RIA, no significant difference was observed between the use of HSA and of BSA in so far as 0.5% bovine gamma globulin was added to the buffer, contradicting those in the reference. The resalts indicated that the cost for the preparation of both kits can be saved. Quality guaranteed kits could be prepared by careful control of the assay values in comparing with those of the reference control sera. In consequence, there is not any technical difficulty in routine production. (Author)

[en] For an effective preparation and utilization of methylendiphosphonate (MDP)-sup(99m)Tc, a typical radioactive bone imaging agent, methods of radiochemical purity (RCP) determination, labelling yields under various conditions, in-vitro stabilities, and biodistributions have been studied. It has been confirmed that the paper chromatography (PC) using 1 M acetate buffer (pH 4.75) and Whatman 3 MM paper is effective for RCP determination in simplicity and resolution point of view. Freeze dried labelling vials consists of 13 mg MDP, 1 mg SnCl₂-2H₂O, pH adjusted to 4.8-5.0, showed more than 98% labelling yield by a simple reconstitution with upto 100 mCi (not more than 7 ml) of Na sup(99m)TcO₄ solution. The compound maintained more than 95% RCP at room temperature until 2 hours from labellina. The data obtained in ligand exchange between MDP-sup(99m)Tc and HSA and the gel permeation chromatography suggest that the MDP-sup(99m)Tc is more stable than PYP-sup(99m)Tc but less stable than MIDA-sup(99m)Tc and DTPA-sup(99m)Tc. After 150 minutes from the I.V. injection of MDP-sup(99m)Tc to mice, the radioactivities accumulated at the three organs such as liver, stomach, and bone were counted. The radioactivity distribution patterns were correlated with the volume, radioactivities, radiochemical purities, and radioactivity concentrations of the injected MDP-sup(99m)Tc. Results indicated that the use of small amount of MDP-sup(99m)Tc having high radioactivity concentration and high radiochemical purity is essential for an efficient bone imaging. It has been confirmed that the previously known methods of radiochemical purity determination cannot sensitiviely detect the sharply affecting trace impurities. A characteristic distribution pattern of crossed B/L- and B/S- lines was observed in case of using MDP-sup(99m)Tc of low RCP. In such a case, rather a higher dosage would be effective for improving the contrast between bone and liver. (Author)

[en] The Ag-sheathed YBa₂Cu₃O_x high-T_c superconducting tape wires were fabricated by the powder-in-tube and rolling techniques. Annealing temperature dependence of transport critical current density J_c at 77K was studied. The optimal annealing temperature of the Ag-doped YBa₂Cu₃O_x tape wires was 910C. Transport J_c reached 1,200 A/cm² in a single filament tape wire and 1,720 A/cm² in a multifilament tape wire at 77K. It was found that the transport J_c was also dependent on the tape wire thickness; the thinner the tape wire, the higher the J_c value

[en] Using stannous chloride, optimum conditions for sup(99m)Tc labelling of some scanning agents such as phytic acid (PA), dimercaptosuccinic acid (DMSA), and calcium diethylenetriaminepentaacetate (Ca-DPTA) were established. Methods of separation and identification of the labelled compounds were practiced by a paper- or thin layer- chromatography. Biodynamic studies of the compounds were also carried out. The results indicate that the molar ratios of the chelating agent and stannous chloride varies only with the concentrations of the chelating agents, and thus the amounts of the stannous chloride per labelling tube were nearly constant (500-600μg) regardless the variation of the molar ratios. It suggests that the given experimental conditions require about 500μg of stannous chloride regardless of the chelating agents. Under alkaline pH, the labelling yields were drastically decreased due to the probable formation of colloidal tin compounds. Biodynamic data showed characteristic patterns with each compound indicating that they are all suitable for the relevant scanning applications. (author)

[en] To establish solid-phase thyroid hormone radioimmunoassay (RIA) systems, a study on immobilization of 3,5,3'-triiodo-L-thyronine (T³) antibodies on the inner wall of polystyrene tubes and on modification of assay buffer systems has been carried out. Into a series of polystyrene tubes, a constant volume of alkaline glutaraldehyde solution was added to obtain glutaraldehyde-coated tubes by self-polymerization. The tubes were then incubated with dilute bovine gamma globulin (BGG) solution and subsequently treated again with glutaraldehyde. The tubes were further treated with dilute antibody solution to react the aldehyde residue on the wall surface with the amino groups of antibodies. After a definite time, the excess antibody solution was decanted and the tubes were washed with plenty of barbital buffer solution. Reaction parameters such as temperature, volume of the glutaraldehyde solution, pH, dilution ratio and temperature of the antibody solution etc., were controlled. The resulting antibody-coated tubes were tested with antigen bindings to verify the validity in RIA use. To the tubes, T³-₁₂₅I of high specific activity, 8-anilino-1-naphthalene-sulfonic acid (ANS), and the modified buffer solution (0.025M-bar barbital buffer, pH 8.2, containing 0.1% bovine serum albumin (BSA), 0.5% BGG, 0.02% merthiolate, 0.58% NaCl, 0.19% ethylenediaminetetraacetate (EDTA) etc.) were added and incubated with or without T³ standard doses. The percentage of the antibody-bound radioactivity (B) to the total radioactivity (T) was calculated. The average range of B/T (%) under a standard dose of up to 4 ng/mL was 30-58. The results indicated that the antibody-coated tubes are usable for solid-phase T³ RIA under the established conditions. Improvement of the binding ability of the immobilized antibody has been proved by introducing BGG as a spacer and by mixing BSA in the immobilization mixture. (author)

[en] Even though a lately reported method of high temperature exchange labelling of o-iodohippuric acid (Hippuran) in the absence of oxidizing agent was considered to be an attractive one, the exchanges mechanism unclear. In this study iodine isotope exchange betwen o-iodohippuric acid (OIH) and radioiodide (¹²⁵I^-) or between OIH and molecular radioiodine (¹²⁵I₂) were carried out at two different temperatures. Rate constants and activation parameters were measured by applying a radio-paper chromatography technique. Since o-iodobenzoic acid is known as a by-product in the exchange labelling of OIH, data were also obtained for the OIB-iodide systems for comparison. The rate constant was increased in order of OIB...¹²⁵I^->OIB...¹²⁵I₂>OIH...¹²⁵I^-> OIH...¹²⁵I₂ and the activation parameters for OIH were generally larger than those for OIB; ΔH unequal to sub(OIH)>ΔH unequal to sub(OIB), ΔS unqueal to sub(OIH)>ΔS unequal to sub(OIB). These results suggest that the mechanism of the high temperature exchange is predominantly nucleophilic even though some electrophilic character can also be involved depending upon reaction conditions. Such a fact may well be caused by a feasible formation of hydrogen bonding type transition state due probably to the ortho substituent effect of-CONHCH₂COOH. Thus, the high temperature exchange method is estimated to be quite effective for labelling Hippuran especially at a small research center where reducing agent-free ¹³¹I is unavailable. (author)