Testing for Drugs in Hair – a Review of Chromatographic Procedures

This article reviews the analysis of drugs and drug metabolites in hair by chromatographic procedures, including the pretreatment steps, and the extraction methods. The general tendency in the last years, to highly sophisticated techniques (GC–MS–NCI, HPLC–MS, GC–MS–MS) illustrates the constant fight for sensitivity.     

Comparative Action Spectrum for Ultraviolet Light Killing of Mouse Melanocytes from Different Genetic Coat Color Backgrounds

The photobiology of mouse melanocyte lines with different pigment genotypes was studied by measuring colony-forming ability after irradiation. The cell lines were wild-type black (melan-a) and the mutants brown (melan-b) and albino (melan-c). Four lamps emitting various UV wavelengths were used. These were germicidal (UVC, 200–280 Dm), 82.3% output at 254 nm, TL01 (UVB, 280–320 nm), 64.2% at 310–311 nm, FS20, broadband with peak output at 312 nm and Alisun-S (UVA, 320–400 nm), broadband with peak output at 350–354 nm. Appropriate filtration reduced the contaminating UVC to nonlethal levels for the longer waverange lamps. Wild-type melan-a was resistant to UVC and UVA compared to the other two cell lines, but the differences were small. The melan-c cell line was more resistant to UVB and markedly more resistant to FS20 than the pigmented lines. With the exception of FS20 responses, melan-b was more sensitive than melan-a to killing by the various UV lamps. There were more pyrimidine dimers (cyclobutane dimers and 6–4 photoproducts) produced in melan-a than in melan-c cells by UVC, UVB and FS20 lamps. Unlike melan-c, melan-a and melan-b showed a strong free radical signal of melanin character with a detectable contribution of pheomelanin-like centers. The contribution of pheome-lanin was higher in melan-b than in melan-a, while the total melanin content in these two cell lines was comparable. The abundant melanin granules of wild-type melan-a melanocytes were well melanized and ellipsoidal, whereas those of melan-b melanocytes tended to be spherical. In the albino line (melan-c) the melanocytes contained only early-stage melanosomes, all of which were devoid of melanin. The results indicate that pigment does not protect against direct effect DNA damage in the form of pyrimidine dimers nor does it necessarily protect against cell death. High pigment content is not very protective against killing by UVC and UVA, and it may photosensitize in UVB the very wavelength range that is of greatest concern with respect to the rising incidence in skin cancer, especially melanoma. It is clear from these studies that, in pigment cells, monochromatic results cannot predict polychromatic responses and that cell death from solar irradiations is a complex phenomenon that depends on more than DNA damage.     

Improper hydrogen C-H...O bonds cause self-association of alpha, beta-enaminoketones containing fluorosubstituted alkyl groups.

Concentration- and temperature-dependent IR, NMR and dipole-moment studies on 4-N,N-dimethylamino-1,1,1-trifluoro-3-buten-2-one and two of its higher homologues showed that these compounds undergo reversible dimerization in nonpolar solvents. Antiparallel "closed" dimers are formed with a network of improper intermolecular C-H...O hydrogen bonds. Quantitative analysis of the 1H NMR data yielded delta H0 = -17.6 kJ mol-1 and delta S0 = -46.9 J deg-1 mol-1. The interactions observed are the strongest among those involving a C-H group reported so far. The complex described here is the first example of a cyclic complex stabilized by two improper C-H...O hydrogen bonds. The conclusions drawn from the solution and solid-state data were confirmed by ab initio calculations.     

Kinetic Study of Metals Sorption on a Resin Modified with Tetrakis(carboxyphenyl)Porphyrin

 The sorption of metal ions (e.g. Cd²⁺, Cu²⁺, Ni²⁺ and Pb²⁺) from aqueous solution on the anion exchange resin Amberlite IRA-904 modified with tetrakis(4-carboxyphenyl)porphyrin (TCPP) was studied in batch equilibrium experiments. The influence of operating variables such as initial pH and contact time between solution and the resin on the equilibrium parameters was measured. The selectivity order of investigated metal ions was evaluated as follows: Pb²⁺ > Ni²⁺ > Cu²⁺ > Cd²⁺. The matrix cations, such as Mg²⁺ and Ca²⁺, exhibit very low affinity for TCPP-modified resin. The rate uptake of the sorption procedure is predominantly controlled by film diffusion. The best retention kinetic was observed for lead where half the saturation of the TCPP-modified sorbent was achieved in less than 5 min. Author for correspondence. E-mail: kryspyrz@chem.uw.edu.pl Received November 20, 2002; accepted January 26, 2003 Published online May 5, 2003     

Theoretical study of the interaction between a high-valent manganese porphyrin oxyl-(hydroxo)-Mn(IV)-TMPyP and double-stranded DNA

Cationic porphyrin derivatives such as meso-tetrakis(4-N-methylpyridinium)porphyrin, TMPyP, have been shown to interact with double-stranded DNA. The manganese derivative, Mn(III)-TMPyP, activated by an oxygen donor like potassium monopersulfate, provides an efficient DNA-cleaving system. Previous experimental work1 has shown that DNA cleavage by the Mn(III)-TMPyP/KHSO(5) system was due to an oxidative attack, within the minor groove of B-DNA, at the C5' or C1' carbons of deoxyribose units. The aim of this study was to use molecular modeling to elucidate the specificity of the interactions between the transient active species oxyl-Mn(IV)-TMPyP and the DNA target. Geometric parameters, charges, and force field constants consistent with the AMBER 98 force field were calculated by DFT methods. Molecular modeling (mechanics and dynamic simulations) were performed for oxyl-(hydroxo)-Mn(IV)-TMPyP bound in the minor groove of the dodecamer d(5'-TCGTCAAACCGC)-d(5'-GCGGTTTGACGA). Geometry, interactions, and binding energy of the metalloporphyrin located at the A.T triplet region of the dodecamer were analyzed. These studies show no significant structural change of the DNA structure upon ligand binding. Mobility of the metalloporphyrin in the minor groove was restrained by the formation of a hydrogen bond between the hydroxo ligand trans to the metal-oxyl and a DNA phosphate, restricting the access of the oxyl group to the (pro-S) H atom at C5'.     

Some properties of topological geons

We investigate the Finkelstein-Misner geons for a non-simply-connected space-time manifold (M, g ₀). We use relations between different Lorentzian structures unequivalent tog ₀ and topological properties ofM given by the Morse theory. It implies that to some pieces of geons we have to associate Wheeler's worm-holes. Geons that correspond to time-orientable Lorentz structures are related tog ₀ by Morse functions that describe the attaching of a handle of index one. In the case of geons associated to time-nonorientable Lorentzian structures, appropriate handles are related to loops along which the notion of time reverses. If we assume electromagnetic properties of geons, then only four species, v, e, p, m, of different geons can exist and geon m has to decay according to mv+p+e.     

Far-infrared spectra of lanthanide complexes with 8-hydroxyquinoline

Summary Vibrational spectra of lanthanide oxines have been measured in the far-infrared region. In addition, the similar yttrium complex was investigated for further experimental evidence for the proposed band assignments. The most important metal-oxygen and metal-nitrogen bond vibrations have been attributed to absorptions between 390–350 cm^–1 and 210–170 cm^–1, respectively.

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Ferne IR-Spektren von Lanthanidenkomplexen mit 8-Hydroxychinolin

Zusammenfassung Es wurden die Vibrationsspektren von Lanthanid-Oxinen im fernen IR-Bereich gemessen. Zusätzlich wurde der analoge Yttrium-Komplex untersucht, um die Bandenzuordnungen experimentell zu stützen. Die wichtigsten Metall-Sauerstoff- und Metall-Stickstoff-Bindungsschwingungen wurden den Absorptionen zwischen 390–350 cm^–1 und 210–170 cm^–1 zugeordnet.

     

Absolute configuration of tert-butyl-1-(2-methylnaphthyl)phosphine oxide

The enantiomers of tert-butyl-1-(2-methylnaphthyl)phosphine oxide 1 have been separated using a homemade HPLC column and an analytical gradient system. Vibrational absorption and circular dichroism spectra for both enantiomers have been measured in CD2Cl2 and CH2Cl2 solutions in the 2000-900 cm(-1) region. The fully relaxed potential energy surface of (S)-tert-butyl-1-(2-methylnaphthyl)phosphine oxide, obtained using the B3LYP functional with a 6-31G basis set, indicated two stable conformers with their populations in a approximately 2:1 ratio. The vibrational absorption and VCD spectra are predicted for these two conformers using the B3LYP functional with a 6-31G basis set. The comparison of predicted and experimental spectra indicated that (+)-tert-butyl-1-(2-methylnaphthyl)phosphine oxide is in the (S)-configuration. This assignment is supported by the ab initio prediction of positive optical rotation for the most stable conformer with an (S)-configuration and the nonequivalence sense of the tert-butyl group chemical shift observed in the 1H NMR spectrum of this enantiomer measured in the presence of (+)-(S)-mandelic acid as a chiral solvating agent.     

Synthesis of Methylenebis(Phosphonate) Analogues of Nucleotide Coenzymes. A Novel Coupling Mechanism

Synthesis of P¹, P²-disubstituted methylenebis(phosphonate)s as inhibitors of inosine monophosphate dehydrogenase is presented.     

Novel Organophosphorus Reagents for the Synthesis of Amines

Abstract:

New organophosphorus equivalents of a² type N-protected amine synthons are presented.