Determination of five abused drugs in nitrite-adulterated urine by immunoassays and gas chromatography-mass spectrometry.

The adulteration of urine specimens with nitrite ion hasseen shown to mask the gas chromatography-mass spectrometry (GC-MS) confirmation testing of marijuana use. This study was designed to further investigate the effect of nitrite adulteration on the detection of five commonly abused drugs by immunoassay screening and GC-MS analysis. The drugs tested are cocaine metabolite (benzoylecgonine), morphine, 11-nor-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH), amphetamine, and phencyclidine. The immunoassays evaluated included the instrument-based Abuscreen ONLINE assays, the on-site Abuscreen ONTRAK assays, and the one-step ONTRAK TESTCUP-5 assay. Multianalyte standards containing various levels of drugs were used to test the influence of both potassium and sodium nitrite. In the ONLINE immunoassays, the presence of up to 1.0M nitrite in the multianalyte standards had no significant effect for benzoylecgonine, morphine, and phencyclidine assays. With a high concentration of nitrite, ONLINE became more sensitive for amphetamine (detected more drug than what was expected) and less sensitive for THCCOOH (detected less drug than what was expected). No effects of nitrite were observed on the results of the Abuscreen ONTRAK assays. Similarly, no effects were observed on the absolute qualitative results of the TESTCUP-5 when testing the nitrite-adulterated standards. However, the produced intensities of the signals that indicate the negative test results were slightly lowered in the THC and phencyclidine assays. The presence of 1.0M of nitrite did not show dramatic interference with the GC-MS analysis of benzoylecgonine, morphine, amphetamine, and phencyclidine. In contrast, nitrite ion significantly interfered with the detection of THCCOOH by GC-MS. The presence of 0.03M of nitrite ion resulted in significant loss in the recovery of THCCOOH and its internal standard by GC-MS. The problem of nitrite adulteration could be alleviated by sodium bisulfite treatment even when the specimens were spiked with 1.0M of nitrite ion. Although bisulfite treatment decomposed all nitrite ions in the sample to recover the remaining THCCOOH by GC-MS, the net recovery of THCCOOH depended on urinary pH and time and conditions of sample storage. The presence of nitrite concentrations that might arise from all possible natural sources, including microorganisms, pathological conditions, and medications, did not interfere with the GC-MS analysis of THCCOOH.

Generation of carbohydrate-deficient transferrin by enzymatic deglycosylation of human transferrin.

Carbohydrate-deficient transferrin (CDT) molecules are transferrin isoforms that lack one or both of the carbohydrate groups attached to a normal human transferrin molecule. CDT has been reported to be a sensitive and specific marker for diagnosing alcoholism. This report demonstrates the in vitro generation of CDT molecules that can potentially be used as the standard in measuring CDT concentrations. This was achieved by deglycosylation of human transferrin with the enzyme Endo-beta-N-acetylglucosaminidase F2 (Endo-F2). The enzyme was immobilized on sepharose beads, which were packed into a column. The immobilization of the enzyme not only eliminated the Endo-F2 contamination of CDT, but also rendered the enzyme suitable for repetitive use. In this manner, it was possible to obtain at least 200 mg of CDT over a period of more than 3 mo, without any noticeable decrease of enzyme activity, using only 3.0 micrograms of enzyme. This proved to be an efficient method for generating CDT.

ONTRAK TESTCUP: a novel, on-site, multi-analyte screen for the detection of abused drugs.

We developed a rapid, sensitive, and simple-to-use multi-analyte diagnostic device for the detection of drugs of abuse in urine: the ONTRAK TESTCUP. No sample or reagent handling is necessary with this device, and the device also serves as the sample collection cup. The TESTCUP contains immunochromatographic reagents that qualitatively and simultaneously detect the presence of benzoylecgonine, morphine, and cannabinoids (delta9-tetrahydrocannabinol [THC] in urine. It is based on the principle of competition between the drug in the sample and membrane- immobilized drug conjugate for antidrug antibodies coated on blue-dyed microparticles. Each drug assay has its own strip, which contains an antibody specific to benzoylecgonine, morphine, or THC. A sample is collected in the TESTCUP, a lid is placed on it, and a chamber at the top of the cup is filled with urine by inverting the cup for 5 s. Urine proceeds down immunochromatographic strips, and the assays are developed. In approximately 3-5 min, the Test Valid bars appear, a decal is removed from the detection window, and the results are interpreted. The appearance of a colored bar at the detection window for each drug indicates a negative result. The absence of color in any specific drug detection window indicates a positive result for that drug. If a positive result is obtained, the same device (cup) can be used for gas chromatographic-mass spectrometric (GC-MS) confirmation. When the precision of the TESTCUP was evaluated, the results obtained were as follows: for urine controls containing drug at 50% of its cutoff concentration, the results were greater than or equal to 96, 98, and 96% negative for benzoylecgonine, morphine, and THC, respectively; for urine controls containing drug at 120% of its cutoff concentration, the results were greater than or equal to 97, 100, and 98% positive for benzoylecgonine, morphine, and THC, respectively. The correlations of clinical sample results using the TESTCUP versus results by GC-MS and the ONTRAK and OnLine assays were assessed. There was 100% agreement between samples prescreened positive by GC-MS and positive by TESTCUP for all three assays. There was 100% agreement between TESTCUP and ONTRAK results and between TESTCUP and OnLine results when testing clinical samples positive and negative for cocaine (benzoylecgonine) or THC. Greater than 99% agreement was observed between TESTCUP and ONTRAK results and between TESTCUP and OnLine results when testing clinical samples positive and negative for morphine. The cross-reactivity of the TESTCUP assay to related drugs and drug metabolites was also determined, and the results were similar to those of the ONTRAK and OnLine assays.

c-myc protein and DNA replication: separation of c-myc antibodies from an inhibitor of DNA synthesis.

Antibodies against human c-myc protein have been reported to inhibit DNA polymerase activity and endogenous DNA synthesis in isolated nuclei, suggesting a role for c-myc in DNA replication. Using the same antibody preparations, we observed equivalent inhibition of simian virus 40 DNA replication and DNA polymerase alpha and delta activities in vitro, as well as inhibition of DNA synthesis in isolated nuclei. However, the c-myc antibodies could be completely separated from the DNA synthesis inhibition activity. c-myc antibodies prepared in other laboratories also did not interfere with initiation of simian virus 40 DNA replication, DNA synthesis at replication forks, or DNA polymerase alpha or delta activity. Therefore, the previously reported inhibition of DNA synthesis by some antibody preparations resulted from the presence of an unidentified inhibitor of DNA polymerases alpha and delta and not from the action of c-myc antibodies.

Production of human c-myc protein in insect cells infected with a baculovirus expression vector.

A cDNA fragment coding for human c-myc was inserted into the genome of the baculovirus Autographa californica nuclear polyhedrosis virus adjacent to the strong polyhedrin promoter. Insect cells infected with the recombinant virus produced significant amounts of c-myc protein, which constituted the major phosphoprotein component in these cells. By immunoprecipitation and immunoblot analysis, two proteins of 61 and 64 kilodaltons were detected with c-myc-specific antisera. The insect-derived proteins were compared with recombinant human c-myc-encoded proteins synthesized in Escherichia coli and Saccharomyces cerevisiae cells. The c-myc gene product was found predominantly in the nucleus by subcellular fractionation of infected insect cells.

Noncoordinate histone synthesis in heat-shocked Drosophila cells is regulated at multiple levels.

Transferring Drosophila tissue culture cells from 25 to 37 degrees C (heat shock) causes histone protein synthesis to become noncoordinate. To determine the level at which this is controlled, the synthesis, degradation, and translation of individual histone mRNAs was studied under both heat shock and control conditions. The increased synthesis of histone H2b protein during heat shock appears to be controlled primarily at the level of translation. During heat shock, H2b mRNA is transcribed at about the same level as in the control. However, H2b mRNA is more stable under heat shock than under control conditions and is predominantly found in polysomes. The reduction in synthesis of H2a, H3, and H4 protein during heat shock appears to be controlled at both the transcriptional and translational levels. Although transcription of H2a, H3, and H4 mRNAs is reduced during heat shock, like H2b mRNA, they are more stable. However, unlike H2b mRNA, these mRNAs are not predominantly associated with polysomes during heat shock. Regulation of H1 synthesis during heat shock is completely different from that of the other histones. During heat shock, H1 mRNA is not transcribed, and unlike all of the other Drosophila mRNAs studied to date, its mRNA is not stable in heat-shocked cells. Results from in vitro translation studies support the conclusion that noncoordinate synthesis of the core histone proteins during heat shock is controlled at the level of translation.