No abstract available

No abstract available

[en] The behavior of several commercial solubilizers (PCS, Readysolv VI, Insta-Gel, and Aquasol) when quenched with an aqueous system was examined. The relationship between the external standard channels ratio (ESR) and the isotope channels (C/R) ratio was determined before and after phase change for both tritium and carbon-14. A comparison was also made between the response of quasi-logarithmic amplification and linear amplification operated in the summed or lesser pulse-height mode. Observed data revealed that neither the ESR nor C/R is a satisfactory method of Quench Correction after phase separation. It does not appear that the phase distribution of the tritium radioactivity has any drastic effects on the results observed

No abstract available

[en] ¹⁵³Sm-citrate solutions were prepared form enriched ¹⁵²Sm₂O₃. ¹⁵³Sm was rapidly bound by Melanoma 2AB cells in tissue culture upon incubation in the presence of ¹⁵³Sm-citrate. In vitro ultracentrifugation studies of ¹⁵³Sm-citrate solutions showed that colloid formation under incubation conditions could have been responsible in part for the uptake by cultured cells. Low uptakes of ⁶⁷Ga-citrate were seen under similar conditions. ¹⁵³Sm-citrate injected into BDF₁mice (Lewis lung carcinoma) and Copenhagen x Fisher rates (Dunning R3327-H prostatic tumors) was concentrated mainly in the liver, with some tumor and bone uptake. The percent of injected dose per organ for ¹⁵³Sm and ⁶⁷Ga in the murine and rat models respectively, 24 h after i.v. dosing, was 17.2 ± 4.7 and 2.0 ± 0.6 (tumor), 63.9 ± 7.9 and 14.4 ± 1.4 (liver) and 0.6 ± 0.1 and 1.3 ± 0.1 (blood); % injected dose g^-1 femur was 6.2 ± 2.7 and 12.9 ± 2.7, respectively. Scintigrams of rats showed qualitative biodistributions similar to the quantitative mouse data obtained by dissection studies. The high hepatic uptake detracted from the otherwise superior tumor localisation of ¹⁵³Sm-citrate when compared to ⁶⁷Ga-citrate in these models. The murine Lewis lung tumor index (% injected dose g^-1 tumor x tumor:blood) was 303.6 for ¹⁵³Sm-citrate and 48.9 for ⁶⁷Ga-citrate, 24 h after injection. (author)

[en] Electron excitation of oxygen molecules, with release of photons due to electron relaxation, is associated with leukocyte phagocytosis. These events are the result of formation of singlet oxygen and/or superoxide anion, and these, in turn, are unique intracellular microbicidal agents. Rate of photon emission can be monitored in a liquid scintillation counter operated at 25--27⁰C in the out-of-coincidence mode. Both phagocytic monocytes and polymorphonuclear leukocytes isolated from human blood emitted photons upon engulfment of opsonized zymosan, or yeast. Rate of photon emission was proportional to the concentration of phagocytes present in the sample. Color quenching of photons was noted when contaminating erythrocytes were present in the sample. For this reason, a technique was developed to prepare highly purified preparations of mononuclear and polymorphonuclear leukocytes devoid of erythrocytes. Control studies indicated that chemiluminescence was inhibited if Ca²⁺ and Mg²⁺ were absent from the test sample. Chemiluminescence appears to be a simple method for determining phagocytosis and intracellular killing on the part of phagocytic monocytes and polymorphonuclear leukocytes present in human blood

[en] The acute toxicity, differential distribution in tissue, and elimination of ScCl₃, ⁴⁶ScCl₃, Sc-EDTA and ⁴⁶Sc-EDTA, in mice, has been investigated. The LD₅₀sup(24hr) doses for ScCl₃ were 440 and 24 mg kg^-1 respectively after intraperitioneal and intravenous injection, and 720 and 108 mg kg^-1 respectively for Sc-EDTA. ⁴⁶ScCl₃ was extensively deposited in the liver and the spleen. ⁴⁶Sc-EDTA was rapidly taken up by the kidney with subsequent elimation via the urine. While-body desaturation kinetics for ⁴⁶Sc-EDTA were found to fit a three compartmental model. The fast elimination phase (T1/2 = 12.75 min; K = 0.05540 min^-1) accounted for 74.6% of the dose; the intermediate phase (T1/2 = 40.2 min; K = 0.01722 min^-1) for 21.8%, and the slow (T1/2 = 5351 min; K = 0.00013 min^-1) for 3.6% of the dose. (author)

[en] The first-pass lung uptake of [¹³¹I]HIPDM was studied in a rabbit model using a conventional single-pass multiple indicator dilution (SPMID) technique with [99mTc]HSA as the intravascular marker. Lung extraction of [¹³¹I]HIPDM determined by the SPMID method was saturable, decreasing from 89.5 +/- 5.8% (mean +/- s.d., n = 4) at 4 nmol kg-1 to 63.8 +/- 6.2% at 1.5 X 10(4) nmol kg-1 relative to the intravascular tracer. The first-pass extraction of [¹³¹I]HIPDM derived from gamma-camera emission imaging data correlated well (R = 0.834) with simultaneously derived SPMID data. The extraction efficiencies were 94.4 +/- 3.3 and 87.9 +/- 3.2 at 200 nmol kg-1 and 68.0 +/- 6.2 and 64.0 +/- 10.7 at 1 X 10(4) nmol kg-1 (n = 4) for the SPMID and gamma-camera methods, respectively. Analysis of the lung arterial effluent blood indicated that no appreciable de-iodination or metabolism of [¹³¹I]HIPDM, within the limits of detection, occurred during the first pulmonary transit

[en] Enriched samarium oxide (98.2% ¹⁵²Sm₂O₃) was irradiated in low neutron flux and high neutron flux reactors to produce ¹⁵³Sm with specific activities of 14.3 GBq and 22.1 TBq mmol-1 Sm, respectively, at the time of use. Formulation of ¹⁵³Sm as [¹⁵³Sm]EDTA, with a 1:10 molar ratio of SM:EDTA, provided a stable radiotracer in vitro and in vivo. High specific activity [¹⁵³Sm]EDTA showed superior uptake in cell culture (20.8 +/- 0.9% vs. 5.5 +/- 0.1% for 6 and 600 pmol Sm per 10(6) cells, respectively) and better tumor index values (51 vs. 37 at 10.9 nmol and 1.09 mumol Sm kg-1, respectively) in the BDF1 mouse/Lewis lung tumor model. High specific activity [153Sm]EDTA scintigrams of Copenhagen x Fisher rats bearing transplanted Dunning R3327 tumors clearly delineated the tumors within 6 hr, with moderate liver and bone uptake and low soft-tissue background. The injected radiotracer underwent rapid central compartment clearance and whole-body elimination. The absence of observed adverse histopathological toxicity combines with high image quality within 6 hr, to support the clinical tumor-imaging potential of this agent. Comparative studies with [⁶⁷Ga]citrate at molar-equivalent doses indicated that high specific activity [¹⁵³Sm]EDTA was a superior radiotracer in these in vitro and in vivo models

[en] As a continuing program in the design of new lung imaging agents to provide information on early lung injury we have developed a series of radioiodinated aliphatic amines which are metabolised by the monoamine oxidase system of the lungs. We now report the synthesis of a series of ω-(4-[¹³¹I]-iodophenyl)alkylamines. (author)