Simultaneous determination of THC-COOH and THC-COOH-glucuronide in urine samples by LC/MS/MS

A fast method using liquid-liquid extraction and HPLC/tandem-mass spectrometry (LC/MS/MS) was developed for the simultaneous detection of 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid beta-glucuronide (THC-COOH-glucuronide) and 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. This highly specific method, which combines chromatographic separation and MS/MS analysis, can be used for the confirmation of positive immunoassay results even without hydrolysis of the sample or derivatisation of extracts. Liquid-liquid extraction was optimised: with ethylacetate/diethylether (1:1, v/v) THC-COOH-glucuronide and THC-COOH could be extracted in one step. Molecular ions of the glucuronide (MH(+), m/z 521) and THC-COOH (MH(+), m/z 345) were generated using a PE/SCIEX turboionspray source in positive ionisation mode; specific fragmentation was performed in the collision cell of an API 365 triple-quadrupole mass spectrometer and yielded major fragments at m/z 345 (for THC-COOH-glucuronide) and m/z 327 as well as m/z 299 for both cannabinoids. Chromatographic separation was performed using a reversed-phase C8 column and gradient elution with 0.1% formic acid/1 mM ammonium formate and acetonitrile/0.1% formic acid. Retention times were 22.2 min for the glucuronide and 26.8 min for THC-COOH. After enzymatic hydrolysis of urine samples with beta-glucuronidase/arylsulfatase (37 degrees C, 5 h), THC-COOH-glucuronide was no longer detectable by LC/MS/MS in urine samples. However, the THC-COOH concentration was increased. For quantitation of THC-COOH, THC-COOH-D(3) was added to the urine samples as internal standard prior to analysis. From the difference of THC-COOH in the native urine and urine after enzymatic hydrolysis, molar concentration ratios of THC-COOH-glucuronide/THC-COOH in urine samples of cannabis users were determined and found to be between 1.3 and 4.5.     

Strategic Standardization in Europe: A Public Choice Perspective

In October 1990, the EC Commission presented a Green Paper in which it outlined a New Approach to European standardization. In particular, standardization was interpreted as a means of furthering the completion of the Internal Market. This paper discusses the impact of the modifications to the process of standard setting, as they have been proposed by the Commission, with respect to the incentives and goals of the major players in the European standardization game, i.e., national and European standardization bodies, industry and the EC Commission. Selected economic models of standardization are applied to investigate the policy impact of the New Approach.     

Comparing the Recognition Memory Test and the Word Choice Test in a Mixed Clinical Sample: Are They Equivalent?

The Recognition Memory Test (RMT) was compared to the Word Choice Test (WCT) within the same fixed neuropsychological battery administered to a mixed clinical sample of 237 adults to empirically evaluate the psychometric equivalence of these two instruments. On average, there was a 3-point difference in raw scores between the two instruments (M _RMT?=?44.3, SD _RMT?=?6.8; M _WCT?=?47.1, SD _WCT?=?4.6; p?d?=?.48). The probability density functions differ substantially at the two ends of the scale but are similarly ≤42. Cross-validation analyses suggest that the RMT cutoff of ≤42 is functionally equivalent to a WCT score of ≤45.     

FACE‐R—A 3D Database of 400 Living Individuals' Full Head CT‐ and Face Scans and Preliminary GMM Analysis for Craniofacial Reconstruction

In the past, improvements in craniofacial reconstructions (CFR) methodology languished due to the lack of adequate 3D databases that were sufficiently large and appropriate for 3‐dimensional shape statistics. In our study, we created the “FACE‐R” database from CT records and 3D surface scans of 400 clinical patients from Hungary, providing a significantly larger sample that was available before. The uniqueness of our database is linking of two data types that makes possible to investigate the bone and skin surface of the same individual, in upright position, thus eliminating many of the gravitational effects on the face during CT scanning. We performed a preliminary geometric morphometric (GMM) study using 3D data that produces a general idea of skull and face shape correlations. The vertical position of the tip of the (soft) nose for a skull and landmarks such as rhinion need to be taken into account. Likewise, the anterior nasal spine appears to exert some influence in this regard.     

A positive theory of the earnings relationship of unemployment benefits

In a wage bargaining model, a stronger earnings relationship of unemployment benefits may reduce wages. Therefore, the benefit structure significantly influences profits and trade union utility, raising the question as to how the benefit structure is determined in the political process. We consider a government that chooses the earnings relationship in order to maximize its political support. Our model predicts a strong earnings relationship under right-wing governments and a weak relationship when unions are influential. Using panel data for 19 OECD countries, we find support for these theoretical predictions. Moreover, we show that the earnings relationship varies negatively with openness.     

Identification of selected psychopharmaceuticals and their metabolites in hair by LC/ESI-CID/MS and LC/MS/MS

Hair samples of patients of psychiatry and hair samples of suicide cases were analysed by liquid-chromatography/ionspray-mass spectrometry (LC/MS) for antidepressants and neuroleptics. Electrospray ionisation (ESI) with in-source collision induced dissociation (ESI/CID) and tandem-mass spectrometry (MS/MS) were used for drug and metabolite identification. Mass spectra library searching was performed using an ESI/CID mass spectra library and a MS/MS spectra library. Furthermore, extracted ion chromatograms were used for the detection of N-desmethyl-metabolites, which were also identified by their fragment-ion spectra. Three examples using these methods are shown: The tricyclic antidepressant maprotiline, the selective serotonin receptor inhibitor (SSRI) citalopram and their desmethylmetabolites as well as the neuroleptic pipamperone were detected and identified in hair extracts. For extraction powdered hair was treated by ultrasonication in methanol and solid-phase extraction was used for sample clean-up prior to LC/MS or MS/MS analysis. These examples demonstrate the power of LC/MS and LC/MS/MS for the detection and identification of drugs in hair extracts using full-scan mode and ESI/CID with library searching or using highly selective LC/MS/MS-analysis with library searching or in multiple reaction monitoring mode.     

Voting on standardisation

This paper analyses equilibria of voting on commodity standards within the framework of a Farrell-Saloner model which takes into consideration the trade-off between network effects and losses from a reduction of variety. Social welfare implications are derived and discussed with respect to manipulations of majority rules. The findings indicate that welfare implications of standards are highly sensitive to the decision procedure and that the choice of the decision rule is non-trivial as it can at least prevent worst outcomes if not guarantee optimal results.     

From nation to class: The changing social role of the Hungarian nobility

Presented at the Conference of Social Stratification and Mobility in Comparative Perspectives, Inter-University Centre, Dubrovnik, Yugoslavia, May 1986.     

Self-employment earnings and returns to education in rural Peru

This article estimates the returns to education for households who derive part of their income from household based non-farm self-employment ventures in rural Peru. While education is an individual level variable, earnings are observed at the household level. This asymmetry complicates both the estimation and the interpretation of the returns to education. This article is the first jointly to incorporate three channels through which education affects household earnings. Education affects earnings through the marginal productivity of labour (worker effect), labour allocation across activities (between-activity allocative effect) and its production externality effect (spillover effect). The results suggest that the between-activity allocative effects of education dominate the returns. This article also makes novel use of economic geography to proxy for the role that access to markets plays in determining these returns. In particular, altitude is a strong predictor of activity choice and the returns to education in this mountainous country.