Practical aspects of internal-sample liquid scintillation counting

Davidson, Jack D.; Feigelson, Philip

doi:10.1016/0020-708x(57)90021-2

Cited by 244 publications

(42 citation statements)

References 20 publications

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“…Raw urine samples were counted in the polyether 611 phosphor of Davidson and Feigelson (9) with 1 ml of urine, 1 ml of water, and 10 to 14 ml of phosphor assuring a one-phase system without crystallization of dioxane. Quenching was estimated by adding 0.1 ml of phosphor containing a known number of counts to each sample.…”

Section: % Hexanementioning

confidence: 99%

See 1 more Smart Citation

Testosterone Production Rates in Normal Adults

Korenman¹,

Wilson²,

Lipsett³

1963

J. Clin. Invest.

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The investigation of clinical and physiological problems related to androgen production has been hampered by lack of an adequate measure of testosterone production. As one approach to this problem, Finkelstein, Forchielli, and Dorfman (1) developed a sensitive method for the measurement of free testosterone in plasma. The subsequent identification of testosterone in the urine (2) as the glucuronoside (3) provided a unique metabolite for the estimation of testosterone production rate by the isotope-dilution method. One such study, using an isotope-derivative method to quantitate testosterone, was briefly reported by Hudson, Coghlan, Dulmanis, and Ekkel (4).We have measured urinary testosterone by an adaptation of the fluorescence reaction described by Wilson (5). This has facilitated the use of the isotope-dilution method for the measurement of testosterone production rates in man. MATERIALS AND METHODSL.S., L.M., G.S., R.S., J.S., C.Z., and M.G. were healthy young adult volunteers C.S. was a 27-year-old white woman in complete remission after treatment for metastatic choriocarcinoma. Regular menses had occurred for the 6 months before study. E.H. was a 27-year-o'dNegro woman with normal menstrual function admitted for treatment of local recurrence of carcinoma of the breast.Absolute ethanol 1 was redistilled by the method of Peterson and his associates (6). Water was glass-distilled after the addition of a few crystals of KMnO4. n-Hexane, ether, chloroform, and methanol were prepared as previously described (7,8 Silica gel G 4 was washed twice with absolute ethanol and once with redistilled ethanol. After the third wash, the wet powder was heated overnight in an oven at 1000 C and then stored at room temperature in a desic-cator. An alcohol eluate of a 10-g sample of the powder should give no colored residue.The steroids 5 used were obtained from commercial sources. Testosterone and testosterone acetate were recrystallized, and the melting points agreed with reported values. Other materials used were human folliclestimulating hormone (FSH) (potency, 0.1 ml = 1 U NIH FSH-S1) contaminated with a small amount of luteinizing hormone, human chorionic gonadotropin (HCG) ,6 and testosterone-4-C 7 (77 ,&c per mg), which was chromatographed in systems A2 and B6 before use.Partition column chromatography. The technique previously described (7) was modified so that extracts of 1.5 days' urine could be resolved on a single column.The glass tube was 48 mm i.d. and 30 mm long with a 55: 50 outer joint at the top. Solvent systems are shown in Table I. Seventy g of silica-alumina catalyst, used as supplied, was mixed with 43 ml stationary phase A and packed in about 140 ml mobile phase A previously poured into the column. The dried urine extract was applied with successive portions of 1.2, 0.6, and 0.3 ml stationary phase A, each mixed with an equal volume of mobile phase A. Each transfer was preceded by placing layers of 2, 1, and 0.5 g dry silicate on the column. To develop the column, the successive solvents were allowed to ...

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Section: % Hexanementioning

confidence: 99%

“…Triplicate samples of the 8 Pilot Chemicals, Watertown, Mass. 9 Carried out in an apparatus designed by the Glowall Corp., Glenside, Pa.…”

Section: % Hexanementioning

confidence: 99%

Testosterone Production Rates in Normal Adults

Korenman¹,

Wilson²,

Lipsett³

1963

J. Clin. Invest.

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“…Samples were also counted in a Packard Tri-Carb liquid scintillation spectrometer, using toluene-C"4 as an internal standard. 4 The chloroform solution, containing 1 to 9 ,ug of bilirubin-C'4 was evaporated in low-potassium glass counting vials,5 the bilirubin was redissolved at 50°C in 0.5 ml 0.5 M Hyamine in methanol 6 (70) and 17 ml of scintillator solution 7 was added (71). Counting efficiency ranged from 44 to 50 per cent.…”

Section: Position Of Radioactive Carbonmentioning

confidence: 99%

The Preparation of Crystalline Bilirubin-C14*

Ostrow¹,

Hammaker²,

Schmid³

1961

J. Clin. Invest.

195

112

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“…Cycloheximide was employed at a concentration of 60 ,xg/ml to ensure maximal inhibition of protein synthesis. Twenty-five grams root slices were incubated 48 hr in 100 ml of incubation medium containing 5 Per cent inhibition = dpm control -dpm cycloheximide treated X 100 dpm control proteins were collected as in the previous experiment and peroxidase isoenzymes A-1, B and C were isolated and purified. …”

Section: Resultsmentioning

confidence: 99%

Incorporation of Carbohydrate Residues into Peroxidase Isoenzymes in Horseradish Roots

Lew

Shannon²

1973

Plant Physiol.

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Sliced root tissue of the horseradish plant (Armoracia rusticana), when incubated with mannose-U-14C, incorporated radioactivity into peroxidase isoenzymes. Over 90% of the radioactivity in the highly purified peroxidase isoenzymes was present in the neutral sugar residues of the molecule, i.e. fucose, arabinose, xylose, mannose. When the root slices were incubated simultaneously with leucine-4,5-'H and mannose-U-14C, cycloheximide strongly inhibited leucine incorporation into the peptide portion of peroxidase isoenzymes but had little effect on the incorporation of "C into the neutral sugars. These results indicated that synthesis of the peptide portion of peroxidase was completed before the monosaccharide residues were attached to the molecule. This temporal relationship between the synthesis of protein and the attachment of carbohydrate residues in the plant glycoprotein, horseradish peroxidase, appears to be similar to that reported for glycoprotein biosynthesis in many mammalian systems.Peroxidase catalyzed reactions are present throughout the plant kingdom and many plants contain multiple forms of the enzyme. Horseradish peroxidase isoenzymes have been highly purified (14, 16) and characterized in terms of their amino acid and carbohydrate compositions (16,21). Recent work in this laboratory established that although the same sugars were present in each isoenzyme, i.e. fucose, arabinose, xylose, mannose, and glucosamine, the carbohydrate content of the isoenzymes varied from 21 to 37% of the molecular weight (21).Despite the fact that glycoproteins are universally present in plants, information concerning the incorporation of carbohydrate residues into specific plant glycoproteins is limited. Several investigators (1, 4, 6, 11) have studied the glycosylation of the hydroxyproline-rich cell wall glycoprotein, extensin. Roberts et al. (12) incubated several plant tissues with "C glucosamine and observed that this compound was a useful and specific precursor of amino sugar residues in plant glycoproteins. The limited studies dealing with the biosynthesis of plant glycoproteins is in sharp contrast to the rapidly growing body of information concerning the biosynthesis of mammalian glycoproteins (3). Nearly all evidence concerning the mechanism of biosynthesis of the heterosaccharide moiety of glycoproteins has been obtained from mammalian systems and

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Practical aspects of internal-sample liquid scintillation counting

Cited by 244 publications

References 20 publications

Testosterone Production Rates in Normal Adults

Testosterone Production Rates in Normal Adults

The Preparation of Crystalline Bilirubin-C14*

Incorporation of Carbohydrate Residues into Peroxidase Isoenzymes in Horseradish Roots

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