Crisis hipertensivas asociadas a arritmia severa por esfuerzo / Hypertensive episodes associated to severe exercise-induced arrhythmia

Se trata de un paciente de 46 años que inicialmente presenta una crisis hipertensiva sin otro diagnóstico asociado. Posteriormente, presenta un episodio de dolor torácico que es diagnosticado de posible pericarditis. Un mes después, presenta nuevo episodio de dolor torácico que es diagnosticado de taquicardia regular con QRS ancho desencadenada por el esfuerzo. El interés del presente caso radica en la escasa frecuencia de la taquicardia con QRS ancho desencadenada con el esfuerzo y en la dificultad para llegar a un diagnóstico adecuado. También destacar su asociación a descontrol tensional y crisis hipertensivas

A case is reported regarding a 46-year old male patient who initially had a hypertensive episode with no other associated diagnosis. He then had an episode of chest pain that was diagnosed as a possible pericarditis. One month later, the patient had a new episode of chest pain that was diagnosed as regular tachycardia with wide QRS precipitated by exercise. The interest of the present case is based on the scant frequency of wide-QRS tachycardia precipiated by exercise and on the difficulty to reach an adequate diagnosis. Its assocation to inadequate blood pressure control and hypertensive episodes also stands out (AU)

Molecularly imprinted polymer solid-phase extraction coupled to square wave voltammetry at carbon fibre microelectrodes for the determination of fenbendazole in beef liver.

A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium for electrochemical detection of fenbendazole. The limit of detection was 1.9x10(-7) mol L-1 (57 microg L-1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission (500 microg kg-1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed. The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton-Robinson Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate of 2.0 mL min-1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 microg kg-1. Results obtained for ten different liver samples yielded mean recoveries of (95+/-12)% and (96+/-11)% for the upper and lower concentration level, respectively.

Density functional theory study of self-association of N-methylformamide and its effect on intramolecular and intermolecular geometrical parameters and the cis/trans population.

The single-point total energy (E) of several acyclic and cyclic oligomers of N-methylformamide (NMF) was computed by the first time without any geometrical restriction, using the B3LYP6-31G* method of the density functional theory in order to determine the effect of self-association on intramolecular geometrical parameters of cis- and trans-NMF, the intermolecular distances of the hydrogen-bonding chains formed by NMF as well as intermolecular association energies including counterpoise corrections. It is concluded that liquid NMF exists mainly as polymers formed by self-association of trans-NMF units, whereas the cis-NMF isomer occurs as isolated units inserted along the chains. These computational results are in accordance with the experimentally determined predominance (ca. 90%) of trans-NMF population by means of (1)H- NMR and other spectroscopic techniques, but in severe contradiction with a recent interpretation of x-ray diffraction data on liquid NMF, postulating a cyclic trimer of cis-NMF (c-C(3)) as the predominating species. The counterpoise-corrected values of the association energy, DeltaE(CP), calculated for cyclic oligomers, increase with the polymerization degree (n) revealing a high grade of cooperative effect for amidic hydrogen-bonded chains. Noteworthy, the difference between the DeltaE(CP) values of the cyclic cis- and trans-homooligomers of NMF is positive for n=2 and 3 but negative for n > or =4.

Molecularly imprinted polymers for on-line clean up and preconcentration of chloramphenicol prior to its voltammetric determination.

The performance of a molecularly imprinted polymer (MIP) as a selective solid-phase extraction sorbent for the clean-up and preconcentration of the antibiotic chloramphenicol is described. The MIP was prepared using chloramphenicol as the template, (diethylamino)ethyl methacrylate as the functional monomer, and ethylene glycol dimethacrylate as the cross-linking monomer, and using tetrahydrofuran as the solvent. Detection of chloramphenicol was carried out by square-wave voltammetry at electrochemically activated carbon fiber microelectrodes. Chloramphenicol was eluted from the MIP microcolumn with methanol. Different experimental variables (sample pH, eluent volume, analyte and eluent flow rates and sample volume) associated with the rebinding/elution process were optimized. For a 250 mL sample, a nominal enrichment factor of 500 was attained, and for a chloramphenicol concentration of 3.0x10(-8) mol L(-1) (9.7 microg L(-1)) a recovery of 96+/-4% was obtained. A range of linearity for chloramphenicol between 3.0x10(-8) and 1.0x10(-5) mol L(-1) was obtained by loading 17 mL of analyte solutions of different concentration, eluting with 0.5 mL methanol, evaporating under a stream of nitrogen and dissolving the residue in phosphate buffer of pH 7.8. The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of chloramphenicol. The applicability of the MIP for both clean up and preconcentration was demonstrated by determining chloramphenicol in ophthalmic solutions and spiked milk at different concentration levels.

Tuning of photo- and electroluminescence of new soluble, PPV-analogous short-chain compounds with naphthalene moieties

A series of oligomers analogous to poly(p-phenylenevinylene) (PPV), combining naphthalene and benzene as aromatic units, have been synthesized by a Knoevenagel reaction. By measuring UV/Vis spectra, photoluminescence (PL) and electroluminescence (EL), we studied the influence of the position of the naphthalene unit as well as the steric and electronic influences of cyano and alkyloxy substituents on the luminescent properties of these compounds.

Electron impact fragmentation patterns of 3,3-dimethyl-1, 2-norbornane derivatives

The electron impact mass spectra of several 3,3-dimethyl-1, 2-norbornanediols, diamines, amino alcohols and related derivatives have been studied and their fragmentation pathways discussed. Different fragmentation patterns were observed, depending not only on the nature of the substituents, but also on their relative positions on the norbornane framework. In general, the dominant peaks in the spectra of these compounds originate from initial C1-C2 bond cleavage (alpha-cleavage) with charge retention on the heteroatom (oxygen or nitrogen) attached at the bridgehead position, followed by hydride shift and loss of the C2-C3 fragment by homolytic cleavage of the C3-C4 bond. This fragmentation pathway leads to a highly stabilized cyclopentenylimmonium or cyclopentenyloxonium ion, which constitutes the base peak in the spectra in most of the studied compounds. Copyright 1999 John Wiley & Sons, Ltd.

Synthesis of substituted 1-norbornylamines with antiviral activity.

The reaction of (+/-)-camphor (7) with triflic anhydride (Tf2O) yields the bridgehead triflate 8. The Nametkin rearrangement of 8 to 3 was realized by treatment with triflic acid (TfOH). The solvolysis of the bridgehead triflates 3 and 8 in acetonitrile affords the N-acetyl-1-norbornylamines 4 and 9. The Pd(0)-catalyzed hydrogenation of 4 and 9 gives the amides 5 and 10. The corresponding 1-norbornylamines 2 and 13 and the N-ethyl derivatives 1, 6, 11, and 12 were obtained by basic hydrolysis or reduction with LiAlH4, respectively, of the amides 4, 5, 9, and 10. The antiviral activity of the hydrochlorides of some of the obtained 1-norbornylamines was evaluated against influenza A, herpes simplex 2, and African swine fever virus. Particularly noticeable is the activity of the hydrochlorides of 1 and 11 against influenza A virus (SI (selectivity index) = 1000).