RESUMEN

OBJECTIVE: To investigate sociodemographic characteristics, clinical and academic training, work setting and salary, clinical activities, and salary and job satisfaction among practicing neuropsychologists in four Nordic countries. METHODS: 890 neuropsychologists from Denmark, Finland, Norway, and Sweden participated in an internet-based survey between December 2013 and June 2015. RESULTS: Three-fourths (76%) of the participants were women, with a mean age of 47 years (range 24-79). In the total sample, 11% earned a PhD and 42% were approved as specialists in neuropsychology (equivalent to board certification in the U.S.). Approximately 72% worked full-time, and only 1% were unemployed. Of the participants, 66% worked in a hospital setting, and 93% had conducted neuropsychological assessments during the last year. Attention deficit hyperactivity disorder, learning disability, and intellectual disability were the most common conditions seen by neuropsychologists. A mean income of 53,277 Euros was found. Neuropsychologists expressed greater job satisfaction than income satisfaction. Significant differences were found between the Nordic countries. Finnish neuropsychologists were younger and worked more hours every week. Fewer Swedish neuropsychologists had obtained specialist approval and fewer worked full-time in neuropsychology positions. Danish and Norwegian neuropsychologists earned more money than their Nordic colleagues. CONCLUSION: This is the first professional practice survey of Nordic neuropsychologists to provide information about sociodemographic characteristics and work setting factors. Despite the well-established guidelines for academic and clinical education, there are relevant differences between the Nordic countries. The results of the study offer guidance for refining the development of organized and highly functioning neuropsychological specialty practices in Nordic countries.

Asunto(s)

RESUMEN

Hydroperoxides formed by autoxidation of common fragrance terpenes are strong allergens and known to cause allergic contact dermatitis (ACD), a common skin disease caused by low molecular weight chemicals. Until now, no suitable methods for chemical analyses of monoterpene hydroperoxides have been available. Their thermolability prohibits the use of gas chromatography and their low UV-absorption properties do not promote sensitive analytical methods by liquid chromatography based on UV detection. In our study, we have investigated different liquid chromatography/mass spectrometry (LC/MS) ionization techniques, electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI), for detection of hydroperoxides from linalool and limonene.Flow injection analysis was used to evaluate the three different techniques to ionize the monoterpene hydroperoxides, linalool hydroperoxide and limonene hydroperoxide, by estimating the signal efficacy under experimental conditions for positive and negative ionization modes. The intensities for the species [M+H]+ and [M+H-H2O]+ in positive ionization mode and [M-H]- and [M-H-H2O]- in negative ionization mode were monitored. It was demonstrated that the mobile phase composition and instrumental parameters have major influences on the ionization efficiency of these compounds. ESI and APCI were both found to be appropriate as ionization techniques for detection of the two hydroperoxides. However, APPI was less suitable as ionization technique for the investigated hydroperoxides.

Asunto(s)

RESUMEN

OBJECTIVE: A combination of esomeprazole, amoxicillin and clarithromycin may be used for Helicobacter pylori eradication. We explored the potential for interactions between these drugs. METHODS: In 2 randomized, 4-way crossover studies, healthy CYP2C19 extensive metabolizers (EMs) received esomeprazole 40 mg once daily (n = 20) or 20 mg twice daily (b.i.d.) (n = 20), clarithromycin 500 mg b.i.d., amoxicillin 1 g b.i.d. or the combination of the 3 drugs for 7 days. In a third randomized, 2-way, crossover study, 6 healthy CYP2C 19 poor metabolizers (PMs) received esomeprazole 40 mg once daily with and without clarithromycin 500 mg b.i.d. for 1 week. RESULTS: Triple therapy with esomeprazole 40 mg increased the area under the plasma concentration-time curve during the dosing interval (AUCtau) from 13.31 micromol x h/l (11.12-15.93) for esomeprazole alone to 22.69 micromol x h/l (18.94-27.17) for triple treatment. Respective AUCtau values with esomeprazole 20 mg b.i.d. were 4.97 micromol.h/l (3.97-6.21) and 11.29 micromol x h/l (9.03-14.12). Clarithromycin and amoxicillin plasma levels were largely unchanged by combination therapy. In PMs, the esomeprazole AUC also approximately doubled when administered in combination with clarithromycin. All treatments were well tolerated. CONCLUSION: Clarithromycin decreases the metabolism rate of esomeprazole, leading to approximately doubled AUC values, both in EMs and PMs.

Asunto(s)

RESUMEN

Unusual effects in liquid chromatographic separations of enantiomers on chiral stationary phases are reviewed with emphasis on polysaccharide phases. On protein phases and Pirkle phases reversal of the elution order between enantiomers due to variation of temperature and mobile phase composition has been reported. Most of the nonanticipated observations have dealt with the widely used polysaccharide phases. Reversed retention order and other stereoselective effects have been observed by variation of temperature, organic modifier and water content in nonpolar organic mobile phases.

Asunto(s)

RESUMEN

The four isomers of almokalant, a new antiarrhythmic substance under investigation, were separated by liquid chromatography on a Chiralcel OD and a Chiralpak AD column containing cellulose and amylose tris(3,5-dimethylphenylcarbamate), respectively. Both chiral stationary phases separate almokalant into the four isomers, but the retention orders are different if the carbamate is derivatized on cellulose or amylose. The Chiralcel OD column was used for the separation and determination of the isomers in urine at levels down to 100 nmol/l for the first three eluted and 200 nmol/l for the last with a relative standard deviation of less than 15%. The fluorescence response was increased by post-column ionization after stereoselective separation on the Chiralpak AD column. The isomers of almokalant could be determined at levels down to 10 nmol/l in plasma with a relative standard deviation of less than 15%.

Asunto(s)

RESUMEN

The two enantiomers of metoprolol and the four enantiomeric forms of alpha-hydroxymetoprolol were separated by liquid chromatography on a Chiralcel OD column containing a cellulose tris(3,5-dimethyl-phenylcarbamate) chiral stationary phase. The column efficiency was strongly dependent on the flow-rate and the enantioselectivity was influenced by temperature. Of utmost importance for the chiral separation was the water content of the mobile organic phase. The separation system was used for the separation and determination of the enantiomers in plasma and urine samples. The metoprolol enantiomers could be determined by fluorescence down to 10 nmol/l of each in plasma with a relative standard deviation of less than 15%.

Asunto(s)

RESUMEN

Numerous publications during the past ten years have described the determination of various calcium channel blockers in biological fluids, using gas and liquid chromatographic techniques. Diltiazem, verapamil, flunarizine and a growing number of dihydropyridines belong to this group of drugs, which in most instances are active at low plasma concentrations. From a bioanalytical point of view these compounds have many features in common, such as high lipophilicity and favourable detection properties.

Asunto(s)

RESUMEN

An automated column-switching system for determination of vanillylmandelic acid in urine is described. The liquid chromatographic system was composed of two separation columns with different selectivity properties, an octadecyl column coated with tributyl phosphate as stationary liquid phase and a silica-based anion exchanger. Urine samples were injected directly onto the first column, where vanillylmandelic acid was separated from the main part of the sample matrix. The internal standard isovanillylmandelic acid was co-eluting with vanillylmandelic acid, and a fraction of the eluate containing both substances was switched to the second column, where separation was performed. To assess peak purity, detection was performed with dual working electrodes in parallel mode. A relative standard deviation of 3.5% was obtained for determination of human urine samples containing 3 microM vanillylmandelic acid, and less than 0.1 microM could be detected.

Asunto(s)

RESUMEN

The enantiomers of metoprolol were determined in plasma samples after direct resolution on a silica bonded alpha 1-acid glycoprotein column. Metoprolol was extracted from plasma into a diethyl ether-dichloromethane mixture and after back extraction to dilute phosphoric acid and adjustment of pH the sample was injected on a Chiral-AGP column for separation of R- and S-metoprolol. It was possible to measure down to 2 nmol per litre plasma with a relative standard deviation of less than 15% by use of gradient elution and fluorescence detection. The analytical method was employed to study the pharmacokinetics of the metoprolol enantiomers after administration of the racemate to humans.

Asunto(s)

RESUMEN

A method is described that allows determination of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in platelet-poor human blood plasma after direct injection of 50-100 microliters of plasma into a coupled-column liquid chromatographic system. The chromatographic system comprised an enrichment column and two separation columns with different selectivity properties. The samples were injected into the C18 enrichment column, which was eluted with a buffer solution as the mobile phase. 5-HT, 5-HIAA and the internal standard 5-hydroxy-N-methyl-tryptamine (5-HMT) were then desorbed by a stronger mobile phase and flushed into a cation exchanger, which separated 5-HT and 5-HMT. 5-HIAA passed straight through and was switched to a C18 column where it was retarded. After 5-HT and 5-HMT had been eluted from the cation exchanger and detected, the eluate from the C18 column was directed to the detector and 5-HIAA was determined. Basic plasma levels, about 4 nM for 5-HT and 30 nM for 5-HIAA, were measured with a relative standard deviation of about 5%.

Asunto(s)

RESUMEN

Metoprolol and its alpha-hydroxy metabolite were determined in plasma down to 2 nmol/l (S.D. 10-15%) after solvent extraction and bonded-phase liquid chromatography with fluorometric detection. The major metabolite with a carboxylic function was also measured in plasma when liquid-solid extraction on a column activated with dodecyl sulphate was applied. In urine the three components were assayed by direct injection of a diluted sample.

Asunto(s)

RESUMEN

A method is described for the simultaneous determination of the deaminated catecholamine metabolites 3,4-dihydroxyphenylethylene glycol (DOPEG) and 3,4-dihydroxymandelic acid (DOMA) in plasma by liquid chromatography with amperometric detection. The compounds are extracted from plasma by adsorption on alumina, then separated on a reversed-phase column coated with tributyl phosphate as the stationary liquid phase. It is a simple and selective method that permits the determination of basal levels of DOPEG and DOMA in plasma with a relative standard deviation of 3%.

Asunto(s)

RESUMEN

An automated liquid chromatographic method for the determination of omeprazole and two metabolites in plasma and urine is described. It utilizes the Technicon Fully-Automated-Sample-Treatment-LC system (FAST(R)-LC). Sample preparation is achieved by air-segmented continuous-flow providing solvent extraction, evaporation to dryness and reconstitution before injection onto a reversed-phase column. The compounds are separated by isocratic or gradient elution with acetonitrile-phosphate buffer mobile phases and quantified by UV-measurements at 302 nm. The limit of determination (relative standard deviation 10-15%) is 50 nmol l(-1) in plasma (800 microl) and 200 nmol l(-1) in urine (200 microl). The sample capacity is six or three samples per hour, depending on the elution mode.

RESUMEN

Methods for the determination of cardiovascular drugs in blood and plasma are critically reviewed with emphasis on gas and liquid chromatographic techniques. The importance of the various procedures is discussed, in particular sample work-up where the conditions for isolation and derivatization of the compounds are decisive for the accuracy and precision of the methods. Compared with other assay techniques chromatographic methods are generally to be preferred owing to their better selectivity. In the review the following groups are discussed: digitalis glycosides, antiarrhythmic agents, beta-adrenoceptor antagonists, vasodilating agents, antihypertensive compounds, and diuretics.

Asunto(s)

RESUMEN

Omeprazole and three of its metabolites, the sulfone (H 168/66), the sulfide (H 168/22) and the hydroxy metabolite (H 195/80), are determined in plasma and urine by liquid chromatographic methods. The compounds are extracted from the biological sample and the extract is subjected to liquid chromatographic separation, either directly or after evaporation of the organic solvent and dissolution in a polar phase. The effluent from the column is UV-monitored at 302 nm and the quantitative evaluation performed by electronic integrator. Both a method with manual sample work-up and automatic injection and a fully automated system, Technicon FAST-LC, have been employed for the analyses. More than 25 000 samples have been assayed so far by these two methods.

Asunto(s)

RESUMEN

Omeprazole, a substituted benzimidazole and a new gastric acid inhibitor, has been determined in plasma and urine, together with three of its metabolites--the sulphide, the sulphone and the hydroxy compound. The methods comprise extraction from the biological materials with methylene chloride, followed either by direct injection of the extract onto a normal-phase liquid chromatography column or evaporation, dissolution and injection onto a reversed-phase system. The compounds were detected using ultraviolet spectrometry. The absolute recoveries obtained were mostly above 95%. The minimum determinable concentration for omeprazole was 20 nmol/l in plasma (relative standard deviation 10-15%) and 50 nmol/l in urine. The metabolites could also be determined at the same levels.

Asunto(s)

RESUMEN

Liquid chromatography with amperometric detection was employed for the determination of the dihydroxycatecholamine metabolites, 3,4-dihydroxyphenylethylene glycol (DOPEG) and 3,4-dihydroxyphenylacetic acid (DOPAC) in plasma. The compounds were isolated from plasma by adsorption onto alumina, the elution from which was found to be strongly dependent on the acid used. Conditions for the separation on octadecyl-bonded silica were evaluated with particular reference to the influence of pH, ion-pairing anions and quaternary ammonium ions. Recoveries of ca 85% and relative standard deviations of about 3% were obtained for the assay of endogenous concentrations.

RESUMEN

A liquid chromatographic method for the determination of free urinary concentrations of epinephrine, norepinephrine and dopamine is presented. For urine samples, pre-purified by adsorption onto alumina, ion-exchange chromatography was, in terms of selectivity, found to be superior to the more widely used reversed-phase chromatography. The column eluates were monitored with an electrochemical detector utilizing a glassy carbon working electrode. The method allows determination of the concentrations in 0.5 ml of normal urine samples with a relative standard deviation below 2%.

Asunto(s)

RESUMEN

Possible arrhythmogenic side-effects of the positive inotropic agent prenalterol were studied in conscious dogs, three to four days after coronary artery ligation. Prenalterol showed a propensity to cause arrhythmias in one out of eight dogs, thereby confirming published data from clinical studies.

Asunto(s)