Nuclear Chicago

Assay of Radioactive Compounds. The radioactive samples were counted on steel planchets in a Nuclear Chicago Model D-47 low-background gas-flow counting chamber with an absolute counting efficiency (estimated by comparison with a standard) of about 20%. 

Uniformly labeled C-8-D with a specific activity of 2.99 juc/mg was administered orally to pregnant females at 2 /xg/kg/day from 6-15 days of gestation. Three females were sacrificed on alternate days during days 6-20 of pregnancy. Triplicate samples of fetus, placenta, blood, brain, abdominal fat, and sartorius muscle were procured from each female. The samples were dissolved in 1 ml of Soluene (Packard Instruments) to which 15 ml of Aquasol were added. Each sample vial was counted for 30 min in a Nuclear Chicago Mark I liquid scintillation counter. 

Radioactivity Analysis. Samples of urine, feces, and tissues were combusted to COo and analyzed for radioactivity (5). By using this method the recovery of radioactivity from samples spiked with C was 95 dt 5%. To determine the radioactivity expired as CO2, 5-ml aliquots of the solution used to trap the CO2 were added to 15 ml of a scintillation counting solution containing 4 grams 2,5-diphenyloxazole (PPO) and 0.1 grams l,4-bis-2(5-phenyloxazolyl)-benzene (POPOP) per liter of 1 1 toluene 2-methoxyethanol. Samples were counted for radioactivity in a Nuclear Chicago Mark II liquid scintillation counter. Counting eflSciency was corrected by the internal standard technique. 

Materials. The water used for all purposes was double-distilled (once with glassware) and deionized (final conductance was less than 1 X 10"6 ohm1 cm."1). Stearic acid (obtained from Sigma Chemical Co.) was at least 99% pure as determined by silica gel thin-layer chromatography (4), and the synthetic L-a(/ ,y-dipalmitoyl) lecithin was about 90% pure (see Ref. 13 for analysis). The ATP-14C and its derivatives were obtained from Nuclear-Chicago or New England Nuclear Corp. and were found to be 95-98% pure as determined by cellulose thin-layer chromatography (16). 

The products were analyzed for chemically combined phenanthrene content by radio assay, based on the beta radiation emitted by the C atoms of the labeled phenanthrene. The radiation count rate of the labeled phenanthrene, measured under standard conditions, was used as a reference. The combined phenanthrene content of subsequent samples was calculated from a direct proportionality between the observed count rate of the samples and their labeled phenanthrene content. The beta radiation of the samples was counted with a thin-window (1.4 mg./sq. cm.) Geiger-Miiller tube and a scaler (Nuclear-Chicago Corp., Model No. 186.). 

Radioisotope Procedures. Radioactive volatile acids separated by Wiseman-Irvin chromatography were collected in 1 ml of 0.5N KOH. The aqueous fraction containing the acid was transferred to a scintillation vial and evaporated to dryness in a vacuum oven at 20 psi and 50 °C. The residue was redissolved in 0.1 ml distilled H2O before adding 4 ml of absolute ethanol and 15 ml of scintillation fluid 2,5-diphenyloxazole (PPO) and 0.01% 1,4-bis[2-(5-phenyloxazolyl)]benzene (POPOP) in toluene. Samples were counted in a liquid scintillation counter (Nuclear Chicago Corp.). 

Figure 6. Schematic diagram of a nuclear gauge for moisture measurement of hulk materials. (Adapted from Nuclear-Chicago Corporation.)...

Determination of Radioactivity. All samples were counted in a Nuclear Chicago Isocap 300 liquid scintillation counter equipped with a Teletype computerized for direct calculation of disintegrations per minute. Fifty microliters of blood were directly counted for radioactivity after solubilization (1 mL of 1 N NaOH). After incubation at room temperature for 15 min the sample was decolorized by adding 200 fxL of hydrogen peroxide and incubating at 80°C for 30 min. The processed samples were mixed with 100 fxL of 80% acetic acid and 15 mL of Insta-gel (Packard), and were counted. Approximately 60-100 mg of tissue were solubilized following the same method as for blood. From the collected urine an aliquot (2 mL) was counted directly with 15 mL Insta-gel. The feces were dried overnight at room temperature, and a 60-100-mg aliquot was combusted (12) and counted for radioactivity. 

SDS, preferably directly into the scintillation vials. Then the vials are shaken with 10 ml of Instagel emulsifier (scintillant Packard) for 3-5 h at 37°C and counted. Efficiency is 7% for and 33% for C. Alternatively the radioactive materials can be solubilized and thus liberated from the electrophoretic support. This can be materialized by, e.g., Bio-Solv BBS-3 (Beckman Instruments, acidic surfactant). The scintillation solution used is composed of 4 g PPO, 0.2 g POPOP, 170 ml Bio-Solv-BBS 3, 60 ml of water, and 770 ml of toluene [242]. Another solubilizer that can be applied is NCS (Nuclear Chicago Solubilizer) with this solubilizer the polyacrylamide or polyacrylamide-agarose gel slices have to be incubated at 65°C for 2 h. Tritiated ribonucleic acid fractions can be solubilized with 10% piperidine at 60°C. Gel slices are incubated in the scintillating vials with the solubilizer for several hours, allowed to dry, dissolved in distilled water (the gel actually swells at this stage), covered with water miscible toluene scintillation fluid and counted. 

Several companies producing scintillation counting equipment, e.g., Nuclear Chicago, Intertechnique, Packard, Picker Nuclear and Beckman, offer flow cell conversion kits. Unfortunately, these cells and also those described in the literature discussed in the review papers mentioned above, have cell volumes from 0.5 to 4 ml, which makes them unsuitable for use in combination with high-performance liquid chromatographic columns. 

Bill recognized immediately the importance of the invention of the scintillation camera, and persuaded Professor Charles Doan, head of the Department of Internal Medicine at Ohio State, to place an order for the first commercial version. This camera was to be built by a new company. Nuclear Chicago, under the leadership of John Kuranz, President. The company was founded in 1947 by John Kuranz and others from the nuclear reactor laboratory of Em-ico Fermi at the University of Chicago. By the early 1970s, Ohio-Nudear of Solon, Ohio, as well as Picker Medical and General Electric, were also providing gamma cameras to hospitals. 

CT-polymerase B (DNA-dependent RNA-polymerase) was obtained from calf-thymus tissues and assayed as reported earlier (71). Activity measurements were performed in a toluen1e system, using a Liquid Scintillation Counter Mark I (Nuclear Chicago). 

The analysis of the radioactivity was performed in a Nuclear Chicago Mark II liquid scintillation spectrometer. 

Packard model 3255 Tricarb and Nuclear Chicago Mark I liquid scintillation spectrometers (LSS) were used for the experiments. 

The influences of extra lead shielding around a Nuclear Chicago Mark I Spectrometer (NCMS) in various configurations were investigated ... 

The results of the count rate linearity are shown in Table 1. The activity of 1-125 varied from 623 CPM to 95,447 CPM (Nuclear Chicago gamma counter). There was a corresponding increase in the 1-125 activity measured in the liquid scintillation counter using the Gamma Vials. The mean of the ratios of the activity of 1-125 as measured by the liquid scintillation counter to the camma counter was. 77 (SD. 014, range. 75 to. 79). 

B. Method 2, The thymidine nucleotides from the supernatant of the enzyme reaction were separated using the method of Weichsel (1974). Briefly, the same aliquots of the supernatant as in Method 1 were applied onto Whatman DE-81 disks on a Millipore filter holder fitted into a suction flasks. The disks were each washed twice with 10 ml of 1 mM ammoniiam formate and 10 ml of distilled water and once with 10 ml of absolute ethanol. After drying the disks were placed in a counting vial with 10 ml of scintillation fluid. Radioactivity was measured in a Nuclear Chicago Mark 2 Scintillation Spectrometer. ... 

The spent fuel storage for the subcritical assemblies and the SUR-100 reactor does not represent any complication due to the fact that the fuel bum-up is very low and they do not require cooling or special shielding. For the Nuclear Chicago Mod. 2000 subcritical assembly, the exposure rate on the outer surface is 5.4 mR/h, and at 1 m distance it is 0.4 mR/h. 

Figure 34 shows the subcritical assembly Nuclear Chicago Mod. 2000. 

Urinary cAMP was analyzed by mean of cAMP assay kit (Radiochemical Centre Amersham England). Samples were added to a liquid scintillant mixture (Instagel, Packard) and counted in a liquid scintillation system Unilux I Nuclear Chicago C 6850- (Normal range in our laboratory is 1440 - 4500 nmoles/24 hours) (8). 

The specific radioactivity of the various bases, after purification, was checked on a Nuclear Chicago Delta Scintillation Counter. 

Nuclear Chicago Technical Bulletin, No. 16 How to Use Badioisotopes with Thin-Layer Chromatography. Nuclear Chicago Corp., Des Plaines, HI., U.S.A. 

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