Biomedical subjects

C Moore

Publications and source records attributed to C Moore.

At least 19 recordsLinked to original sources

PubMed2001

Inhibition of CMP-sialic acid transport into Golgi vesicles by nucleoside monophosphates.

We examined the interactions of nucleotides with the CMP-sialic acid transporter in order to better understand which features play a role in binding and to investigate the relationship between binding and subsequent transport. With respect to the sugar, the transporter requires a complete ribose ring for tight binding, and the 2'-ara hydrogen makes an important contact. The enzyme exhibits little specificity with respect to the 2'- and 3'-hydroxyls, as it tolerated substitutions ranging from fluorine to an azido group. In the base, the C4 amine and C2 carbonyl groups make important contacts, while the N3 nitrogen does not. However, adding a methyl group to N3 dramatically reduced binding, indicating that mass at this position sterically hinders binding. Adding a group at C5 had either no effect or slightly enhanced binding. To determine if the transporter recognizes these CMP analogues as substrates, we assayed them for their ability to trans stimulate CMP-sialic acid import. These data suggest that the enzyme transports a wide variety of NMPs, and the rate of transport is inversely proportional to the K(I) of the analogue. The importance of our findings for understanding the specificities of the different nucleotide-sugar tranlocators and the design of novel glycosylation inhibitors are discussed.

Animals↗

PubMed2001

Induction of multiple signaling loops by MuSK during neuromuscular synapse formation.

At the neuromuscular junction, two motor neuron-derived signals have been implicated in the regulation of synaptogenesis. Neuregulin-1 is thought to induce transcription of acetylcholine receptor (AChR) genes in subsynaptic muscle nuclei by activating ErbB receptors. Neural agrin aggregates AChRs by activating the receptor tyrosine kinase MuSK. Here, we show that these two signals act sequentially. Agrin, by activating MuSK, induces the synthesis and aggregation of both MuSK and ErbB receptors. ErbB acts downstream of MuSK in synapse formation. In this way, MuSK activation leads to the establishment of a neuregulin-1-dependent signaling complex that maintains MuSK, ErbB, and AChR expression at the synapse of electrically active muscle fibers.

Agrin↗

PubMed2001

Comparison of point-of-collection screening of drugs of abuse in oral fluid with a laboratory-based urine screen.

Oral fluid is becoming increasingly useful for the detection of drugs, since it is a non-invasive specimen to collect and, because collection is directly observed, it is difficult to adulterate. A point-of-collection (POCT) oral fluid drug analysis kit has been developed for use in many drug testing situations. This paper summarizes the results of field evaluations of the ORALscreen System for screening of drugs in oral fluid. The ORALscreen System consists of an oral fluid collection device and a test device containing a lateral flow membrane immunoassay system. Paired samples (oral fluid and urine) were collected from drug users and the results from the ORALscreen POCT system were compared to urine screening results conducted in a licensed laboratory. The results demonstrate that the ORALscreen System has excellent percent agreement with the laboratory-based urine screening test results for the detection of cocaine and opiates through 2.5-3 days following drug use, respectively. Tetrahydrocannabinol (THC) was detected by ORALscreen on the day of use and 1 day after use. Good correlation between urine and oral fluid screening results was observed for the methamphetamine positive samples; however, the number of days following drug use was not determined.

Clinical Laboratory Techniques↗

PubMed2001

Integrating primary medical care with addiction treatment: a randomized controlled trial.

CONTEXT: The prevalence of medical disorders is high among substance abuse patients, yet medical services are seldom provided in coordination with substance abuse treatment. OBJECTIVE: To examine differences in treatment outcomes and costs between integrated and independent models of medical and substance abuse care as well as the effect of integrated care in a subgroup of patients with substance abuse-related medical conditions (SAMCs). DESIGN: Randomized controlled trial conducted between April 1997 and December 1998. SETTING AND PATIENTS: Adult men and women (n = 592) who were admitted to a large health maintenance organization chemical dependency program in Sacramento, Calif. INTERVENTIONS: Patients were randomly assigned to receive treatment through an integrated model, in which primary health care was included within the addiction treatment program (n = 285), or an independent treatment-as-usual model, in which primary care and substance abuse treatment were provided separately (n = 307). Both programs were group based and lasted 8 weeks, with 10 months of aftercare available. MAIN OUTCOME MEASURES: Abstinence outcomes, treatment utilization, and costs 6 months after randomization. RESULTS: Both groups showed improvement on all drug and alcohol measures. Overall, there were no differences in total abstinence rates between the integrated care and independent care groups (68% vs 63%, P =.18). For patients without SAMCs, there were also no differences in abstinence rates (integrated care, 66% vs independent care, 73%; P =.23) and there was a slight but nonsignificant trend of higher costs for the integrated care group ($367.96 vs $324.09, P =.19). However, patients with SAMCs (n = 341) were more likely to be abstinent in the integrated care group than the independent care group (69% vs 55%, P =.006; odds ratio [OR], 1.90; 95% confidence interval [CI], 1.22-2.97). This was true for both those with medical (OR, 3.38; 95% CI, 1.68-6.80) and psychiatric (OR, 2.10; 95% CI, 1.04-4.25) SAMCs. Patients with SAMCs had a slight but nonsignificant trend of higher costs in the integrated care group ($470.81 vs $427.95, P =.14). The incremental cost-effectiveness ratio per additional abstinent patient with an SAMC in the integrated care group was $1581. CONCLUSIONS: Individuals with SAMCs benefit from integrated medical and substance abuse treatment, and such an approach can be cost-effective. These findings are relevant given the high prevalence and cost of medical conditions among substance abuse patients, new developments in medications for addiction, and recent legislation on parity of substance abuse with other medical benefits.

Adult↗

PubMed2001

Determination of methadone in urine using ion trap GC/MS in positive ion chemical ionization mode.

Methadone is a potent analgesic and sedative. It is widely used in the treatment of heroin addiction and is often encountered in forensic specimens. In electron impact (EI) gas chromatography/mass spectrometry (GC/MS) mode, methadone produces predominantly a m/z 72 ion, which is not sufficiently characteristic for identification. Determination of the molecular ion, which can be achieved using chemical ionization (CI) provides diagnostic information and better identification of the drug. This paper describes the development of a positive ion CI GC/MS procedure, using a liquid reagent gas and ion trap instrumentation, for the determination of methadone and its metabolites in urine. CI generally produces a single molecular ion spectrum, but optimization of the reagent gas parameters increases the fragmentation of the molecule, allowing determination of ion ratios if required. The procedure is sensitive, diagnostic and is currently in routine use in our laboratory.

Gas Chromatography-Mass Spectrometry↗

PubMed2001

Multipathways for transdifferentiation of human prostate cancer cells into neuroendocrine-like phenotype.

The neuroendocrine (NE) cell is a minor cell population in normal human prostate glands. The number of NE cells is increased in advanced hormone-refractory prostate carcinomas (PCA). The mechanism of increased NE cell population in these advanced tumors is poorly understood. We examined molecular mechanisms which may be involved in the regulation of the transdifferentiation process of human PCA cells leading to a NE phenotype. We compared PCA cell lines LNCaP and PC-3 in the following medium conditions: steroid-reduced (SR), interleukin-6 (IL-6)-supplemented, or dibutyrate cAMP (db-cAMP)-supplemented. We found that androgen-responsive C-33 LNCaP cells responded to all treatments, having a neuronal-like morphology. In contrast, C-81 LNCaP cells, having a decreased androgen responsiveness, had a less pronounced effect although followed a similar trend. Androgen-unresponsive PC-3 cells showed little change in their morphology. Grown in the SR condition, the level of neuron-specific enolase (NSE), a marker of neuronal cells, was upregulated in C-33 LNCaP cells, while to a lesser degree in the presence of IL-6. In the presence of db-cAMP, the NSE level in C-33 cells was decreased, lower than that in control cells. An opposite effect was observed for C-81 LNCaP cells. Nevertheless, the NSE level was only elevated in db-cAMP-treated PC-3 cells, but no change was found in PC-3 cells grown in the SR- or IL-6-supplemented medium. Thus, a similar gross phenotypic change may correlate with differential molecular expressions. We also analyzed the expression of protein tyrosine phosphatase alpha (RPTPalpha) since it plays a critical role in normal neuronal differentiation and signaling. Our results showed that the expression of RPTPalpha correlates with the NE phenotypic change of LNCaP cells in the SR condition. In summary, our data clearly show that the molecular process by which cultured human prostate cancer cells undergo a transdifferentiation process to a NE cell-like phenotype is accompanied by differential expressions of different markers, and a gross NE cell-like phenotype can occur by exposing PCA cells to different pharmacological agents.

Androgens↗

PubMed2001

Five subunits are required for reconstitution of the cleavage and polyadenylation activities of Saccharomyces cerevisiae cleavage factor I.

Cleavage and polyadenylation of mRNA 3' ends in Saccharomyces cerevisiae requires several factors, one of which is cleavage factor I (CF I). Purification of CF I activity from yeast extract has implicated numerous proteins as functioning in both cleavage and/or polyadenylation. Through reconstitution of active CF I from separately expressed and purified proteins, we show that CF I contains five subunits, Rna14, Rna15, Pcf11, Clp1, and Hrp1. These five are necessary and sufficient for reconstitution of cleavage activity in vitro when mixed with CF II, and for specific polyadenylation when mixed with polyadenylation factor I, purified poly(A) polymerase, and poly(A) binding protein. Analysis of the individual protein-protein interactions supports an architectural model for CF I in which Pcf11 simultaneously interacts with Rna14, Rna15, and Clp1, whereas Rna14 bridges Rna15 and Hrp1.

Adenosine Triphosphatases↗

PubMed2001

Evaluation of the rodent micronucleus assay by a 28-day treatment protocol: Summary of the 13th Collaborative Study by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Environmental Mutagen Society of Japan (JEMS)-Mammalian Mutagenicity Study Group (MMS).

To examine whether micronucleus tests can be incorporated into general toxicology assays, we performed micronucleus tests applying the treatment protocols typically used in such assays. In this 13th Collaborative Study of the CSGMT, both rats and mice were tested, although rats were used in the majority of the studies. Fifteen mutagens were tested in rats, mainly by oral (p.o.) administration. Micronucleus induction was evaluated 2, 3, and 4 days, and 1, 2, 3, and 28 days after the beginning of the treatment in the peripheral blood, and at 28 days in the bone marrow. Of the 15 chemicals that induced micronuclei in rats in short-term assays, two chemicals (1,2-dimethylhydrazine.2HCl and mitomycin C) were negative in all our experiments, possibly because of insufficient dose levels. The remaining 13 were positive within the estimated dose range of a general toxicology assay, suggesting the possibility of integrating the micronucleus assay into general toxicology assays. Three patterns were observed in micronucleus induction during the period of repeated treatment: (1) gradual increases in micronucleus frequency with sequential doses, (2) a peak at 3-5 days followed by gradual decreases in micronucleus frequency with sequential doses, and (3) a rapid increase in micronucleus frequency followed by a plateau. We evaluated factors that might have been involved in those patterns, such as the spleen function, target organ exposure, extramedullary hematopoiesis, hypothermia, and hypoxia. Another factor we considered was dosage. Because the dosages employed in a general toxicity assay are usually lower than those used in short-term micronucleus assays, this discrepancy was considered the greatest potential problem for integrating the micronucleus assay into general toxicology assays. Our results indicate that the integration of the micronucleus assay into a 28-day toxicological assay is feasible. To serve this purpose, blood samples collected 4 days after the beginning of treatment and blood and bone marrow samples collected at autopsy should be examined. Furthermore, although it is recognized that mice may be suitable for performing independent micronucleus assays, we propose that rats can provide biologically important and relevant information regarding potential chemical mutagens that can be evaluated under conditions used in the conduct of general toxicology studies.

Animals↗

PubMed2001

Blockade of NMDA receptors by MK-801 reverses the changes in striatal glutamate immunolabeling in 6-OHDA-lesioned rats.

A lesion of the dopamine (DA)-containing nigrostriatal pathway with 6-hydroxydopamine (6-OHDA) results in an increase in the density of nerve terminal glutamate immunolabeling and in the mean percentage of asymmetrical synapses containing a discontinuous postsynaptic density [Meshul et al. (1999) Neuroscience 88:1-16]. Similar alterations in striatal glutamate synapses have been reported following blockade of striatal DA D-2 receptors with subchronic haloperidol treatment [Meshul et al. (1994) Brain Res 648:181-195]. The haloperidol-induced change in glutamate synapses was blocked by coadministration of the N-methyl-D-aspartate (NMDA) noncompetitive receptor antagonist MK-801. In order to determine if blockade of NMDA receptors could alter the density of nerve terminal glutamate immunolabeling following a 6-OHDA lesion of the nigrostriatal pathway, MK-801 was administered to lesioned animals for 14 days. In addition, the number of apomorphine-induced contralateral rotations was determined prior to and following the administration of MK-801. MK-801 administration reversed the increase in the density of nerve terminal glutamate immunolabeling due to a 6-OHDA lesion. There was a small but significant decrease in the number of apomorphine-induced contralateral rotations following administration of MK-801 compared to the number of rotations prior to treatment with the NMDA antagonist. These results demonstrate that blockade of postsynaptic NMDA receptors affects the density of presynaptic glutamate immunolabeling and that this change in nerve terminal glutamate density is associated with a decreased behavioral response to direct DA receptor stimulation. Whether the effect of MK-801 is directly on the striatum or acts through other excitatory pathways of the basal ganglia remains unclear.

Adrenergic Agents↗

PubMed2001

Interpretations of a teratogen warning symbol.

BACKGROUND: Warning symbols are used on teratogenic medications to communicate the message that women should (1) not take that medication if they may already be pregnant, and (2) not get pregnant while taking that medication. Communications research indicates that people interpret symbols or pictures in different ways. Other studies have shown that patients do not always receive education materials that are part of prescription protocol. Researchers at the Centers for Disease Control and Prevention (CDC) tested the interpretation of the teratogen warning symbol and its ability to convey the correct information without accompanying education. METHODS: A teratogen warning symbol currently printed on some medication packaging uses graphics and text warning the user not to get pregnant. Researchers interviewed women of childbearing age about their interpretation of the warning symbol and its meaning. Ninety-seven women were interviewed in a variety of locations, including public health clinics, literacy and job training offices, health clubs, and malls. RESULTS: Only 21% of women interpreted correctly without prompting that they should either not take the medication if they are pregnant or not get pregnant while taking the medication. Twenty-seven percent of women first thought the symbol meant the package contained birth control medication, and 24% said it simply indicated the package contained drugs or medicine. An additional 7% said they did not know what the symbol was supposed to mean; 39% of respondents offered circumstances in which prescription medications might be shared. CONCLUSIONS: Misinterpretation of warning symbols can result in serious consequences. This research should serve as an urgent call for mandating education for all patients receiving drugs with teratogenic properties, and careful pretesting and modification of warning symbols before they are used on medications with teratogenic effects. Published 2001 Wiley-Liss, Inc.

Abnormalities, Drug-Induced↗

PubMed2001

Oral dyskinesias and morphological changes in rat striatum during long-term haloperidol administration.

RATIONALE: Neuroleptic-induced oral dyskinesias in rats, a putative analogue to human tardive dyskinesia, may be due to increased glutamate release within the striatum. This may lead to excitotoxic degeneration and, as a consequence, persistent motor side effects. OBJECTIVES: To investigate whether alterations in glutamatergic synapses within the striatum are associated with the development of neuroleptic-induced oral dyskinesia. METHODS: Haloperidol was administered for 20 weeks, and rats with high and low levels of vacuous chewing movements (VCM) were analyzed for morphological changes with electron microscopy at three time points. RESULTS: At week 8, the high VCM rats had a larger nerve terminal area and lower density of nerve terminal glutamate immunoreactivity than the other groups. After 18 weeks of treatment, the nerve terminal area was increased relative to controls in both the high and low VCM groups. After discontinuation of treatment, there were no significant morphological differences between the groups, but the level of VCM was still significantly increased in the high VCM group. CONCLUSIONS: These results show that striatal glutamatergic transmission is affected during haloperidol treatment and the nerve terminal area and the density of nerve terminal glutamate immunoreactivity are important in determining the VCM response to haloperidol treatment. This indicates that increased glutamatergic synaptic activity in the striatum contributes to the development of human tardive dyskinesia.

Animals↗

PubMed2001

Neural response to perception of volume in the lateral occipital complex.

Projection of a 3D scene onto the 2D retina necessarily entails a loss of information, yet perceivers experience a world populated with volumetric objects. Using simultaneous behavioral and neural (fMRI) measures, we identify neural bases of volume perception. Neural activity in the lateral occipital cortex increased with presentation of 3D volumes relative to presentation of 2D shapes. Neural activity also modulated with perceived volume, independent of image information. When behavioral responses indicated that observers saw ambiguous images as 3D volumes, neural response increased; when behavioral data revealed a 2D interpretation, neural response waned. Crucially, the physical stimulus was identical under both interpretations; only the percept of volume can account for the increased neural activity.

Adult↗

PubMed2001

Comparison of cisatracurium-induced neuromuscular blockade between immediate postpartum and nonpregnant patients.

STUDY OBJECTIVES: To evaluate and compare cisatracurium-induced neuromuscular blockade and intubating conditions between immediate postpartum (PP) and nonpregnant (NP) patients. DESIGN: Prospective control study. SETTINGS: University Hospital Center. PATIENTS: 44 ASA physical status I and II patients: 22 immediate postpartum (PP) patients (<48 hours after delivery) scheduled for elective postpartum tubal ligation and 22 nonpregnant (NP) patients (>40 weeks from prior pregnancy) scheduled for elective gynecological procedures. INTERVENTIONS: General anesthesia was induced intravenously (IV) with thiopental sodium 5 mg/kg, fentanyl 2.0 to 3.0 ug/kg, midazolam 0.015 to 0.025 mg/kg, and cisatracurium 0.2 mg/kg. Evoked electromyographic responses of the adductor pollicis muscle were obtained by supra-maximal train-of-four stimulation of the ulnar nerve every ten seconds via surface electrodes at the wrist. Intubation was attempted at 90 s after completion of cisatracurium administration and again at 120 seconds if the first attempt was unsuccessful. The intubating anesthesiologist assessed the intubating conditions with four variables: jaw relaxation, vocal cord immobility and exposure, patient/diaphragmatic movement, and overall intubating impression. Intraoperative anesthetic was maintained with 30% oxygen, 70% nitrous oxide, and 1% end-tidal isoflurane, as tolerated. Patient temperature was maintained at 35.5 degrees to 37.5 degrees Celsius (C), and end-tidal carbon dioxide at 30 to 36 mmHg. MEASUREMENTS AND MAIN RESULTS: The mean onset times to 50%, 90%, and maximal T(1) depression and mean time to 25% T(1) recovery in the PP group (68 +/- 19 sec, 110 +/- 26 sec, 147 +/- 32 sec, 60 +/- 6 min) were significantly less than those in the NP group (80 +/- 17 sec, 131 +/- 28 sec, 181 +/- 44 sec, 69 +/- 12 min), respectively (p < 0.05). All patients were successfully intubated on the first attempt at 90 seconds. 91% of the NP group and 81% of the PP group had excellent overall intubating conditions. CONCLUSIONS: This is the first published control study to compare the effects of cisatracurium between NP and PP patients. The results suggest that the mean onset time and clinical duration of cisatracurium are significantly shorter in immediate postpartum patients than those in nonpregnant female patients.

Adult↗

PubMed2001

Mental models change rapidly with implicitly acquired information about the local environment: a two-tone image study.

The projection of 3-D objects to 2-D images necessitates a loss of information, thus the shape of volumetric objects depicted in images is inherently ambiguous. The results of 3 experiments suggest observers use mental models of the local visual environment to constrain image interpretation. These models change quickly and dramatically to accommodate implicitly acquired information. Observers viewed very high-contrast (2-tone) images of novel volumetric objects. Before priming, novel 2-tone images appeared 2-D. After incidental exposure to similar objects in grayscale or familiar objects in 2-tone, the test images appeared volumetric. Incidental leaming appears to alter observers' mental models, thus causing an alteration in image interpretation in the absence of any image change. Highlights were interpreted more accurately than shadows, suggesting shadows play a secondary role in shape recovery.

Adolescent↗

PubMed2001

Factors affecting the initiation of substance abuse treatment in managed care.

AIMS: A long-standing concern of clinicians in addiction treatment is that a large number of individuals who are admitted to treatment do not return to actually begin the program. We identified characteristics that predict treatment initiation. DESIGN: In-person structured interviews were conducted with consecutive admissions to a large outpatient program (N = 1204), and the health plan's automated registration data were used to determine treatment attendance. We compared those who returned to begin treatment with those who did not. SETTING: The study was conducted at the Chemical Dependency program of a large group model health maintenance organization (HMO). PARTICIPANTS: Study subjects were individuals age 18 or over admitted to the program. MEASUREMENT: Study variables included DSM-IV alcohol and drug dependence and abuse, Addiction Severity Index problem severity, motivation and treatment entry measures. FINDINGS: Those who were drug-dependent were less likely to begin treatment than those dependent only on alcohol. Measures of motivation, such as work-place pressures and the patient's perception of the importance of alcohol treatment, predicted starting treatment for individuals who were alcohol-dependent only or alcohol- and drug-dependent. Among patients who were dependent only on alcohol, women were more likely than men to start treatment, and for those who were drug-dependent, being employed and having higher drug severity scores predicted starting treatment. CONCLUSIONS: Screening at intake may identify those at risk of not returning after admission to start treatment. Clinicians may consider making additional efforts during the intake process to engage individuals who are unemployed and have drug (as opposed to alcohol) disorders and less motivation.

Adolescent↗

PubMed2001

Ultrasonography by emergency physicians in patients with suspected cholecystitis.

This article investigates the use of bedside abdominal ultrasonography (BAU) performed by emergency physicians (EPs) to screen patients for cholelithiasis and cholecystitis. In this prospective study EPs performed BAU on 116 patients. Agreement between BAU and formal abdominal ultrasound (FUS) performed in the radiology department for detecting cholelithiasis and cholecystitis was determined using Kappa statistics. Test characteristics of BAU for detecting cholelithiasis and acute cholecystitis were calculated. Agreement between BAU and FUS was 0.71 for cholelithiasis and 0.46 for acute cholecystitis. Test characteristics of BAU for cholelithiasis were sensitivity 92%, specificity 78%, positive predictive value (PPV) 86%, negative predictive value (NPV) 88%. Test characteristics of BAU for acute cholecystitis compared with clinical follow-up were sensitivity 91%, specificity 66%, PPV 70%, NPV 90%. BAU may be used to exclude cholelithiasis and is sensitive for cholecystitis. However, when EPs with limited experience identify cholecystitis a confirmatory test is warranted before cholecystectomy.

Acute Disease↗

PubMed2001

Outcome of liver transplantation for hepatitis B: report of a single center's experience.

Results of liver transplantation (LT) for hepatitis B have improved significantly with the use of hepatitis B immune globulin (HBIG) and/or lamivudine. The aim of this study is to review the long-term outcome of patients who underwent LT for hepatitis B. Records of 41 patients who underwent LT for hepatitis B and survived 3 months or longer post-LT were reviewed. Twenty patients were administered no immunoprophylaxis or short-term intramuscular HBIG, whereas 21 patients were administered high-dose intravenous (IV) HBIG. Median post-LT follow-up in these 2 groups was 76 months (range, 4 to 155 months) and 25 months (range, 4 to 68 months), respectively. Hepatitis B recurred in 15 (75%) and 4 patients (19%) who underwent LT in the pre-HBIG and post-HBIG eras, respectively. Cumulative rates of recurrent hepatitis B at 1 and 3 years post-LT in these 2 groups were 66% and 77% and 20% and 20%, respectively (P <.001). Recurrent hepatitis B in the post-HBIG era correlated with antibody to hepatitis B surface antigen titer less than 100 IU/L. Nine patients with recurrent hepatitis B were administered lamivudine for 13 to 49 months (median, 28 months); 6 patients continued to have stable or improved liver disease, whereas 3 patients developed virological breakthrough with slow deterioration of liver disease. Long-term IV HBIG is effective in preventing recurrent hepatitis B. The risk for recurrent hepatitis B is negligible after the first year post-LT. Among patients with no virological breakthrough, lamivudine can stabilize or improve liver disease for up to 4 years in patients with recurrent hepatitis B post-LT.

Adult↗

PubMed2001

The determination of 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in hair using negative ion gas chromatography-mass spectrometry and high-volume injection.

The determination of 11-nor-delta9-THC-9-carboxylic acid (THC-COOH) in hair specimens at the sensitivity required to detect marijuana users is a difficult analytical problem. A sensitive and specific method has been developed for the quantitative assay of THC-COOH in hair. Hair specimens were washed, incubated in sodium hydroxide, subjected to solid-phase extraction, and analyzed using high-volume injection coupled with negative chemical ionization (NCI) mass spectrometry. A common disadvantage of chemical ionization, the production of a single mass-to-charge ratio ion, was also addressed. By specific selection of the derivatizing agent, three ions were monitored, allowing the calculation of two ion ratios, as in electron impact mode. The method was applied to several hair specimens taken from known marijuana users and workplace specimens. This is the first publication describing the use of high-volume injection and NCI mass spectrometry for the determination of THC-COOH in hair.

Adult↗