New England Nuclear

E. Rapkin, Guide to Preparation of Samples for Liquid Scintillation Counting , New England Nuclear Corp, Boston, Mass (1975)... 

Uniformly labeled 2,4-dichlorophenol- C (purchased from New England Nuclear Corp, Boston, Mass.) was used in the tracer preparation. This provided a label at all carbon positions in the dibenzo-dioxin structure. 2,7-Dichlorodibenzo-p-dioxin- C after initial cleanup by fractional sublimation, contained approximately 5% of an impurity, detected by thin layer chromatography (TLC) which gave mass peaks at 288, 290, 292, and 294 in the mass spectrometer, consistent with a trichloro-hydroxydiphenyl oxide. This is probably the initial condensation product of the Ullman reaction and is most likely 2-(2,4-dichlorophenoxy)-4-chlorophenol. It was removed easily by extractions with aqueous... 

Materials. I-EGF was either made by iodinating mouse EGF (Biomedical Technologies Inc.) by the chloramine T method, to a specific activity of approximately 1-2 Ci/ xmol, using Na- I (Amersham) or purchased from New England Nuclear. Phorbol diterpene esters were purchased from Sigma. Palytoxin was isolated from Palythoa tuberculosa as previously described (1). 

Mossbauer. The Mossbauer emission spectroscopy measurements were made using the Co 7 doped catalyst as a stationary source. The moving absorber was Fe enriched K4Fe(CN) -3H20. Both the Co 7 and the absorber were obtained from New England Nuclear. The con-... 

I-BGT solution Prepare a 200 uM I-BGT stock solution from lyophilized I-BGT (Perkin Elmer/New England Nuclear, Boston, MA). 

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). 

Available from New England Nuclear, 549 Albany St., Boston, Mass. 02118, U. S. A. These and other labelled compounds may be available from other venders. 

New England Nuclear) and cell homogenates as described in the text. 

Radiolabeling of Brain Glycolipids. Thy-1 glycolipid was labeled biosynthetically using a previously described method (7). Five to seven day mice of either AKR/J (H-2, Thy-1.1) or ICR Swiss (Thy-1.2) strain mice were used for each preparation. Each mouse pup was injected intracranially with 8 pi of sterile saline solution containing 5 pci [1- 4C]-N-acetylmannosamine (ManNAc) (54.5 mCi/mmol, New England Nuclear, Boston MA). This solution was injected into both sides of the head at a point 1-2 mm anter-... 

Technetium Isotopes. NH, cO, half-life 61 days), obtained from New England Nuclear, and NH TcO, from Amersham-Searle, were used in this study. The presence of reduced technetium was determined by extracting the Tc(7+) into... 

Na I, carrier free, in 0.1N NaOH was obtained from New England Nuclear Co. Orosomucoid, or its appropriate derivative (100 Pg) was iodinated with 1 mC of Na l by a modificaiton of the method of Greenwood et al. (8). The iodinated glycoproteins, purified by passage through a column of Sephadex G-25, were recovered with specific activities ranging from 0.5 to 0.8 pCi/Pg. 

Radiolabelled Solutes. 3H-hydrocortisone (New England Nuclear), -butanol (New England Nuclear), - C-octanol (New England Nuclear) and 3H-vidarabine (ARA-A, courtesy of Dr. D.C. Baker, University of Alabama) were used in the permeability experiments. These compounds were diluted with phosphate buffered saline (PBS, pH 7.3) to form stock solutions. The stock solutions were diluted within the donor compartments of the diffusion cells to have approximately 25 nCi/ml radioactivity per donor compartment. 

P]-Iabelled nucleoside triphosphates—Radiochemical Centre, Amersham, Bucks. U.K. or New England Nuclear, 2, New Road, Southampton, U.K. Deoxyribonucleoside triphosphates—Boehringer, P.-L. 

That one or more of these assumptions may be open to question is suggested by the very recent studies of Ebert and Prockop (8) and by subsequent work in our laboratory with another batch (No. 73-253) of 3,4-tritiated proline obtained from the New England Nuclear Corp. In experiments with this material, less tritium appeared in the water than in the studies described in Table V. Thus, under the conditions of the studies described in Table V, 96,800 d.p.m. of tritiated water and 186,000 d.p.m. of tritiated hydroxyproline were found. In experiments with both uniformly labeled C14-proline and the new batch of 3,4-tritiated proline, H3/C14 ratios for hydroxyproline and proline were 1.79 and 2.56, respectively, leading to an A/B value (cf. Table IV) of 0.70. 

Ebert and Prockop (8) carried out similar studies with 3,4-triti-ated proline in chick embryos, and reported ratios of 0.73 and 0.74. Information supplied by Prockop (32) indicates that this material was from a batch (New England Nuclear Corp.) different from those used by us. They converted the isolated hydroxyproline to pyrrole and found ratios of the H3/C14 values for pyrrole to hydroxyproline of 0.61 and 0.64 (these values were corrected for loss of carboxyl C14, assuming random labeling). We have recently converted the H3-hydroxyproline obtained in our experiments with the new batch of 3,4-tritiated proline to pyrrole (32), and obtained values of 0.70 and 0.73. However, conversion of this hydroxyproline to N-carbobenzoxy-4-ketoproline did not lead to a significant decrease in specific activity, suggesting that little tritium was present at carbon atom 4 of the isolated hydroxyproline. 

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