Ahai C. Lua

Profiles of urine samples from participants at rave party in Taiwan: prevalence of ketamine and MDMA abuse

Drug abuse patterns are different due to cultural, social and geographical differences. Methamphetamine (MA) is the most important drug of abuse in Taiwan followed by opiates. Recently, there has been an increase of ketamine and MDMA abuse in disco dancing clubs. Here, we report the patterns of drug abuse by the participants in a metropolitan city disco-dancing club and the general public in Taiwan. The positive rates of common drugs of abuse detected in samples collected from participants in a dancing club were as follows: MDMA, 75.7%; ketamine, 47.0%; MA, 41.6%; opiates, 0%. Marijuana and cocaine were detected at much lower rates (3.4 and 4.7%, respectively). Ketamine and one of the amphetamines were detected together in 42.9% of the samples. The positive rates in samples collected from police detainees suspected of drug abuse in the general public were as follows: MA, 76.0%; OPA, 37.0%; MDMA, 6.0%; ketamine, 2.0%.

LUNG TOXICITY OF PARAQUAT IN THE RAT

In a rat model of paraquat-induced lung injury, pulmonary alveolar lavage fluid metabolic parameters were assessed to establish damage, and the use of surfactant was employed as a protective agent. Three groups of adult male Sprague-Dawley rats received intraperitoneal injection of paraquat (35 mg/kg body weight) in 1 ml saline, or received 1 ml saline, or no material. On d 3, 7, 14, and 21 after injection, pressure-volume curves and pulmonary alveolar lavage fluids were obtained. On d 3 paraquat significantly increased the lung wet/dry weight ratio and protein content but lowered phosphatidylcholine levels. There were no marked changes at other time points in the parameters examined. The pressure-volume curves initially moved downward and to the right on d 3 and 7 and then returned to control levels in the paraquat-treated rats. Immediate intratracheal administration of Survanta after paraquat injection (70 mg/kg body weight) tended to increase the survival rate on d 1 compared to rats without Survanta administration. Our results suggest that administration of exogenous surfactant may play a role in the treatment of patients poisoned with paraquat.In a rat model of paraquat-induced lung injury, pulmonary alveolar lavage fluid metabolic parameters were assessed to establish damage, and the use of surfactant was employed as a protective agent. Three groups of adult male Sprague-Dawley rats received intraperitoneal injection of paraquat (35 mg/kg body weight) in 1 ml saline, or received 1 ml saline, or no material. On d 3, 7, 14, and 21 after injection, pressure-volume curves and pulmonary alveolar lavage fluids were obtained. On d 3 paraquat significantly increased the lung wet/dry weight ratio and protein content but lowered phosphatidylcholine levels. There were no marked changes at other time points in the parameters examined. The pressure-volume curves initially moved downward and to the right on d 3 and 7 and then returned to control levels in the paraquat-treated rats. Immediate intratracheal administration of Survanta after paraquat injection (70 mg/kg body weight) tended to increase the survival rate on d 1 compared to rats without Survanta administration. Our results suggest that administration of exogenous surfactant may play a role in the treatment of patients poisoned with paraquat.

Preparation of immunoaffinity columns for direct enantiomeric separation of amphetamine and/or methamphetamine.

Immunoaffinity chromatographic columns were prepared for direct enantiomeric determination of racemic methamphetamine and amphetamine in this study. The stationary phase was synthesized by covalently bonding an anti-D-methamphetamine monoclonal antibody onto a pre-activated support (e.g. silica, sepharose 4B). Chromatographic results revealed that the immunoaffinity columns achieved enantiomeric separation of racemic amphetamine and methamphetamine. The immunoaffinity columns also have the ability to directly extract D-methamphetamine from urine by changing the pH of the mobile phase, this ability making it practical for the columns to determine a very low concentration of D-methamphetamine in urine.

Replacing Immunoassays for Mephedrone, Ketamines and Six Amphetamine-Type Stimulants with Flow Injection Analysis Tandem Mass Spectrometry

A screening procedure was developed for the simultaneous detection of mephedrone, six amphetamine-type stimulants (ATS), ketamine and its two metabolites with electrospray ionization flow injection analysis tandem mass spectrometry (FIA-MS-MS). Urine samples were fortified with deuterated analogues as internal standards, extracted with ethyl acetate and analyzed with FIA-MS-MS. The mass analyzer was operated in multiple reaction monitoring mode. Two product ions were monitored for each drug and internal standards. For each analyte, the limit of detection was less than 4 µg/L, within-day and between-day precisions (percent coefficient of variation) at three different concentrations were less than 7.3% and bias was between -17.3 and 11.8%. Total analysis time with FIA-MS-MS is 1.8 min per sample. A group of 215 urine samples were screened with immunoassay for ATS and analyzed with FIA-MS-MS and gas chromatography-mass spectrometry (GC-MS) for ketamines and ATS. The analysis of ATS by immunoassay and GC-MS was 96.7% concordant. The analysis of three ketamines and seven ATS by FIA-MS-MS and GC-MS was 97.2% concordant. The FIA-MS-MS procedure is efficient, accurate, flexible and capable of detecting analytes of different chemical groups. It can replace immunoassays for the screening of new designer drugs when commercial immunoassays are unavailable.

Detection of serologic responses to GB virus C/ hepatitis G virus infection

OBJECTIVES To investigate the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) and compare the serologic responses to various GBV-C/HGV markers in eastern Taiwan aborigines. METHODS We used RT-PCR and anti-HGenv u-plate to investigate the prevalence of GBV-C/HGV in eastern Taiwan aborigines. We also used ELISA, dot blot assay, and Western blot to detect the serologic responses to various GBV-C/HGV markers. RESULTS The prevalence of GBV-C/HGV RNA in the general population of eastern Taiwan aborigines is about 5% (17/317), while 14% (43/317) have anti-E2 antibodies. There were no significant differences in antibody titer against one consensus core peptide (PPSSAAACSRGSPR) between GBV-C/HGV RNA-positive and -negative sera. Only 23 of 42 serum samples positive in the anti-HGenv u-plate EIA assay were positive (55%) in the dot blot assay. No positive signal was detected by Western blot using either recombinant NS3 or commercial E2 proteins. CONCLUSIONS Antibodies against one consensus core peptide (PPSSAAACSRGSPR) may not constitute a good marker for the detection of GBV-C/HGV viremia. For the detection of anti-E2 antibodies, the anti-HGenv u-plate assay is more sensitive than the dot blot assay. Western blot assay is not a sensitive method for detecting GBV-C/HGV infection.

Cigarette smoking has a differential effect on the plasma level of clozapine in Taiwanese schizophrenic patients associated with the CYP1A2 gene -163A/C single nucleotide polymorphism.

Objective The efficacy of clozapine clearance has been shown to be associated with smoking and genetic polymorphism of CYP1A2. This study aims to investigate the effect of smoking on the plasma level of clozapine in Taiwanese schizophrenic patients and its relevance to the CYP1A2 gene −163A/C single nucleotide polymorphism. Materials and methods A total of 143 hospitalized schizophrenic patients who had received clozapine therapy for at least 14 days were enrolled in this study. The trough plasma concentration of clozapine was measured with LC/MS/MS. The −163A/C variant in the CYP1A2 gene was identified by DNA sequencing and restriction fragment length polymorphism analysis. The effect of smoking on the clozapine level was examined by multiple linear regression analysis and its relation to the −163A/C variant of the CYP1A2 gene was analyzed using a general linear model with Bonferroni correction. Results Patients with smoking habits showed a significantly lower plasma level of clozapine than those without smoking habits (P=0.022) and the difference in clozapine levels between smokers and nonsmokers appeared to be significant in the individuals carrying the homozygous −163A allele (P=0.02). It was also found that nonsmokers carrying the −163A allele tended to have higher plasma levels of clozapine. This tendency was not found in the individuals with smoking habits. Conclusion Cigarette smoking has a significant impact on the plasma level of clozapine in Taiwanese schizophrenic patients carrying the homozygous −163A allele in the CYP1A2 gene. Cigarette smoking may increase the clearance of clozapine in these patients.

Inhibition by ketamine and amphetamine analogs of the neurogenic nitrergic vasodilations in porcine basilar arteries

The abuse of ketamine and amphetamine analogs is associated with incidence of hypertension and strokes involving activation of sympathetic activities. Large cerebral arteries at the base of the brain from several species receive dense sympathetic innervation which upon activation causes parasympathetic-nitrergic vasodilation with increased regional blood flow via axo-axonal interaction mechanism, serving as a protective mechanism to meet O2 demand in an acutely stressful situation. The present study was designed to examine effects of ketamine and amphetamine analogs on axo-axonal interaction-mediated neurogenic nitrergic vasodilation in porcine basilar arteries using techniques of blood-vessel myography, patch clamp and two-electrode voltage clamp, and calcium imaging. In U46619-contracted basilar arterial rings, nicotine (100μM) and electrical depolarization of nitrergic nerves by transmural nerve stimulation (TNS, 8Hz) elicited neurogenic nitrergic vasodilations. Ketamine and amphetamine analogs concentration-dependently inhibited nicotine-induced parasympathetic-nitrergic vasodilation without affecting that induced by TNS, nitroprusside or isoproterenol. Ketamine and amphetamine analogs also concentration-dependently blocked nicotine-induced inward currents in Xenopus oocytes expressing α3β2-nicotinic acetylcholine receptors (nAChRs), and nicotine-induced inward currents as well as calcium influxes in rat superior cervical ganglion neurons. The potency in inhibiting both inward-currents and calcium influxes is ketamine>methamphetamine>hydroxyamphetamine. These results indicate that ketamine and amphetamine analogs, by blocking nAChRs located on cerebral perivascular sympathetic nerves, reduce nicotine-induced, axo-axonal interaction mechanism-mediated neurogenic dilation of the basilar arteries. Chronic abuse of these drugs, therefore, may interfere with normal sympathetic-parasympathetic interaction mechanism resulting in diminished neurogenic vasodilation and, possibly, normal blood flow in the brainstem.

The Alpha-2A Adrenergic Receptor Gene -1291C/G Single Nucleotide Polymorphism is Associated with the Efficacy of Methylphenidate in Treating Taiwanese Children and Adolescents with Attention-Deficit Hyperactivity Disorder

Objective The therapeutic effect of methylphenidate (MPH) in treating attention-deficit/hyperactivity disorder (ADHD) has been related to the alpha-2A adrenergic receptor (ADRA2A) gene -1291C/G single nucleotide polymorphism (SNP). We investigated the effect of MPH in treating Taiwanese children and adolescent with ADHD and its relation to the ADRA2A gene -1291C/G SNP. Methods The subjects with DSM-IV ADHD diagnosis underwent a titration period to find out the dose of MPH for maintenance treatment. After 4 weeks maintenance treatment, the effect of MPH was evaluated by the Swanson, Nolan and Pelham version IV total scores. The subjects with more than 25% score reduction were referred to responders and those with ≥50% improvement were considered as better responders. The -1291C/G variant of the ADRA2A gene was identified by DNA sequencing and what relevance it has to the MPH response was examined by binary logistic regression analysis. Results Of the 59 subjects, 44 (74.6%) were responsive to MPH treatment and the responsiveness was not shown to be associated with the ADRA2A gene -1291C/G SNP. As the responsive subjects were categorized as moderate responders and better responders and subjected to statistical analysis, the GG homozygotes showed a greater chance to have a better response to MPH treatment than CC homozygotes (p=0.02), with an odds ratio of 32.14 (95% CI=1.64–627.80). Conclusion The ADRA2A gene -1291C/G SNP is associated with the efficacy of MPH for the treatment of ADHD in Taiwanese children and adolescents. The responsive subjects bearing homozygous -1291G allele are more likely to have a better response to MPH treatment.

A simple and high throughput parallel dual immunoaffinity liquid chromatography-mass spectrometry system for urine drug testing

A simple and rapid method for direct quantitation of drugs in human urine samples was developed using a system composed of an automatic column switch and two home-made capillary immunoaffinity columns (CIACs, 100 μm × 15 cm). Before being injected by an autosampler into the system, the urine sample was filtered through a 0.22 μm membrane. The alternating column regeneration was achieved by using two identical CIACs. One column underwent analyte elution while the other column underwent column regeneration simultaneously. 6-Acetylmorphine (6AM) and oxycodone (OCOD) were studied as examples of opiates in urine. Linear calibration curves were obtained in the concentration ranges of 40–200 ng mL−1 and 50–400 ng mL−1, with a limit of quantitation of 22 ng mL−1 and 47 ng mL−1 for 6AM and OCOD, respectively. The results of this method exhibited good inter-day accuracy and precision. Furthermore, the present method was successfully applied to the determination of 6AM in urine samples of drug abusers.