Biosynthesis of murine terminal deoxynucleotidyltransferase

An immunoprecipitation assay for measuring synthesis of murine terminal deoxynucleotidyltransferase (EC 2.7.7.31) has been developed using rabbit antiserum to calf terminal transferase. The antiserum precipitates a single Mr = 60,000 polypeptide (TdT-60) from all cell lines and tissues that contain enzymologically demonstrable terminal transferase. This polypeptide is not precipitated from labeled extracts of cells that lack terminal transferase by enzymological criteria. TdT-60 fractionates with terminal transferase during phosphocellulose chromatography and sediments with it in a sucrose gradient. TdT-60 is not detectably processed to lower molecular weight polypeptides, and terminal transferase activity sediments as a Mr = 60,000 activity; thus, we believe it to be the active form of terminal transferase. Using this assay we have demonstrated that terminal transferase is synthesized in both the murine thymus and the bone marrow at a rate proportional to its biochemically measured steady state level. After cortisone treatment of mice, the Mr = 60,000 polypeptide disappears from the thymus and then reappears as the thymus begins to be repopulated.

Genomic stability of gibbon oncornavirus

The 70S RNAs from several gibbon type C viruses were examined for sequence homology by molecular hybridization using complementary DNA probes. The sequence homology was found to vary with each virus isolate. The genome from one isolate was examined for genomic stability after the virus was experimentally passaged through three unrelated gibbons. The genomic homology remained unchanged after three passages, having greater than 93% homology based on complementary DNA-70S RNA hybridization and melting temperature analysis of the duplex. The genome from another isolate was similarly found to be unchanged after the virus was naturally transmitted in gibbons. The genomic variation found in the various isolates is not the consequence of recent horizontal transmission from a common virus.

Natural transmission of gibbon leukemia virus

Gibbon leukemia virus can infect prenatal gibbons through in utero infection or postnatal gibbons through contact transmission. The transmission of infectious virus was from viremic gibbons and not from uninfected or antibody-positive animals. The two modes of transmission could be distinguished by the amount of proviral DNA integrated into the muscle tissue of viremic gibbons. Muscle of gibbons infected postnatally had little or no proviral DNA, whereas gibbons infected prenatally had a large quantity of proviral DNA.

Comparison of enzyme immunoassay and gas chromatography for determination of carbamazepine and ethosuximide in human serum

Patients' sera were analyzed for carbamazepine and ethosuximide by enzyme immunoassay (x) and gas chromatography (y), and the results were compared. The correlation coefficients were: for carbamazepine, x vs. y 0.94 (n = 93); for ethosuximide, x vs. y 0.99 (n = 30). These results suggest that the two methods could be used interchangeably. Ten serum samples supplemented with carbamazepine (2.5 to 12.5 mg/liter) and ethosuximide (20.0 to 130.0 mg/liter) were analyzed by both methods. The correlation coefficients were: x vs. y 0.99 (n = 10) for carbamazepine and x vs. y 0.99 (n =10) for ethosuximide.

Comparison of enzyme immunoassay and gas chromatography for determination of carbamazepine and ethosuximide in human serum

Patients' sera were analyzed for carbamazepine and ethosuximide by enzyme immunoassay (x) and gas chromatography (y), and the results were compared. The correlation coefficients were: for carbamazepine, x vs. y 0.94 (n = 93); for ethosuximide, x vs. y 0.99 (n = 30). These results suggest that the two methods could be used interchangeably. Ten serum samples supplemented with carbamazepine (2.5 to 12.5 mg/liter) and ethosuximide (20.0 to 130.0 mg/liter) were analyzed by both methods. The correlation coefficients were: x vs. y 0.99 (n = 10) for carbamazepine and x vs. y 0.99 (n =10) for ethosuximide.

Radioimmunoassay and enzyme immunoassay compared for determination of digoxin

Patients' sera were analyzed for digoxin by using two different radioimmunoassays and an enzyme immunoassay. Quantitative results obtained by enzyme immunoassay (I) were compared to results obtained on aliquots of the same sample by the radioimmunoassays (II and III). The correlation coefficients were: I vs. II 0.90, n=108; I vs. III 0.94, n=102; and II vs. III 0.95, n=158. Day-to-day precision (10 days) on a low control (1.3 mug/liter) and a high control 3.0 mg/liter), expressed as coefficients of variation, were: I, 13% and 7.8%, II, 4.0% and 4.7%; and III, 8.9% and 4.2%. Ten digoxin-supplemented samples (0-8 mug/liter) were analyzed by the three methods. Correlation coefficients were: supplemented sample vs. I, O.99; supplemented sample vs. II, 0.97; supplemented sample vs. III, 0.98.

Radioimmunoassay and enzyme immunoassay compared for determination of digoxin

Patients' sera were analyzed for digoxin by using two different radioimmunoassays and an enzyme immunoassay. Quantitative results obtained by enzyme immunoassay (I) were compared to results obtained on aliquots of the same sample by the radioimmunoassays (II and III). The correlation coefficients were: I vs. II 0.90, n=108; I vs. III 0.94, n=102; and II vs. III 0.95, n=158. Day-to-day precision (10 days) on a low control (1.3 mug/liter) and a high control 3.0 mg/liter), expressed as coefficients of variation, were: I, 13% and 7.8%, II, 4.0% and 4.7%; and III, 8.9% and 4.2%. Ten digoxin-supplemented samples (0-8 mug/liter) were analyzed by the three methods. Correlation coefficients were: supplemented sample vs. I, O.99; supplemented sample vs. II, 0.97; supplemented sample vs. III, 0.98.

Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin

Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin

Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin

Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

Primidone analyses: correlation of gas-chromatographic assay with enzyme immunoassay

Serum specimens from patients on primidone therapy were assayed by two currently available procedures: a commercially available enzyme immunoassay (EMIT) and a published gas-chromatographic procedure. Both procedures were done with commercially available materials and equipment. Results by the two procedures agreed well, which suggests that the two methods could be used interchangeably. For the 94 specimens studied, the correlation coefficient was 0.98, and the least-squares values of slope and intercept were, respectively, 0.97 and 0.51 mg/liter.

Primidone analyses: correlation of gas-chromatographic assay with enzyme immunoassay

Serum specimens from patients on primidone therapy were assayed by two currently available procedures: a commercially available enzyme immunoassay (EMIT) and a published gas-chromatographic procedure. Both procedures were done with commercially available materials and equipment. Results by the two procedures agreed well, which suggests that the two methods could be used interchangeably. For the 94 specimens studied, the correlation coefficient was 0.98, and the least-squares values of slope and intercept were, respectively, 0.97 and 0.51 mg/liter.

Effects of alkylation of phosphodiesters and of bases of infectivity and stability of tobacco mosaic virus RNA

Upon ethyl nitrosourea treatment of RNA of tobacco mosaic virus, up to four phosphodiester groups may be alkylated per molecule without chain breakage, as shown be sucrose gradient centrifugation. This indicates that ribophosphotriesters are quite stable. However, when this alkylation reaction is of longer duration and 6 to 10 triesters are formed, then an average of 1 to 2 breaks occurs and little or no intact RNA can be isolated. Methyl nitrosourea is less effective in forming triesters (about 25% of total alkyl groups compared to about 65% for ethyl nitrosourea), and a greater number of alkyl groups can, therefore, be introduced before breaks occur. Diethyl sulfate and dimethyl sulfate, which alkylate almost only the bases of nucleic acids, do not cause significant degradation of RNA of tobacco mosaic virus, even when as many as 70 alkyl groups are bound. All types of alkylation cause similar losses in viral infectivity at low levels of alkylation. Thus, an average of two chemical events leads to one lethal event, regardless of the nature of the alkylating reaction, which, for example, is with dimethyl sulfate about 65% on the N-7 guanine while with ethyl nitrosourea it is about 65% on phosphodiesters. It is thus concluded that all alkyl groups, whether on the base or on the phosphate, have the same potential to cause inactivation and that inactivation of RNA can result from phosphotriester formation per se.

The specificity of different classes of ethylating agents toward various sites of HeLa cell DNA in vitro and in vivo

The sites and extent of ethyl products of neutral ethylation of HeLa cell DNA by [14-C]diethyl sulfate, [14-C]ethyl methanesulfonate, and [14-C]ethylnitrosourea have been determined in vitro and in vivo, and found to differ significantly depending on the ethylating agents. Diethyl sulfate and ethyl methanesulfonate ethylate the bases of HeLa cell DNA in the following order: 7-ethylguanine greater than 3-ethyladenine greater than 1-ethyladenine, 7-ethyladenine greater than 3-ethylguanine, 3-ethylcytosine, O-6-ethylguanine. Ethyl bases accounted for 84-87% of the total ethyl groups associated with HeLa cell DNA. Ethylnitrosourea, in contrast, has particular affinity for the O-6 position of guanine. It ethylates the bases of HeLa cell DNA in the following order: O-6-ethylguanine, 7-ethylguanine greater than 3-ethyladenine greater than 3-ethylguanine, 3-ethylthymine greater than 1-ethyladenine, 7-ethyladenine, 3-ethylcytosine. Ethylation of the bases only accounts for 30% of the total ethylation in the case of ethylnitrosourea. The remaining 70% of the [14-C]ethyl groups, introduced in vivo and in vitro, are in the form of phosphotriesters which after perchloric acid hydrolysis are found as [14-CA1ethanol and [14-C]ethyl phosphate. In contrast, phosphotriesters amounted to only 8-20% of total ethylation in in vivo or in vitro diethyl sulfate and ethyl methanesulfonate treated HeLa cell DNA, and 25% of the total methylation in in vitro methylnitrosourea treated HeLa cell DNA. Alkylation at the N-7 and N-3 positions of purines in DNA destabilizes the glycosidic linkages. Part of 7-ethylguanine and 3-ethyladenine are found to be spontaneously released during the ethylation reaction. Incorporation of the 14-C of the alkylating agents into normal DNA bases of HeLa cells can be eliminated by performing the alkylations, in the presence of cytosine arabinoside, for 1 hr.

Effects on rats of exposure to heat and vibration

Restrained adult male rats of the Sprague-Dawley strain were exposed for a 20-min duration to sublethal intensities of heat, vibration, and to the combination of heat and vibration. The incidence of mortality resulting from simultaneous exposure to both environmental stresses was significantly greater than would be predicted if these stresses were to act independently of each other. Hematocrit, hemoglobin, and serum glutamic-oxalacetic transaminase levels were significantly elevated immediately after vibration. Heat in combination with vibration increased these values although heat stress per se caused no change from control levels. Twenty-four hours after exposure to the combination of vibration and heat, hematocrit and hemoglobin levels returned to normal but the serum glutamic-oxalacetic transaminase levels were still significantly elevated. Significant increases in heart, kidney, and adrenal weights were observed immediately after exposure to the combination of environmental stresses. Possible modes of action are discussed.

Submitted on November 16, 1961