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PubMed1999

The stabilities of calcium arsenates at 23+/-1 degrees C.

The stabilities of calcium arsenate compounds were established by analysis of suspensions made with varying molar Ca/As ratios. Solution chemistry analyses determined the concentrations of calcium and arsenic and pH. The phases that were shown to form in order of descending pH were Ca(4)(OH)(2)(AsO(4))(2).4H(2)O, Ca(5)(AsO(4))(3)OH (arsenate-apatite), Ca(3)(AsO(4))(2).3 23H(2)O, Ca(3)(AsO(4))(2).4 14H(2)O, Ca(5)H(2)(AsO(4))(4).9H(2)O - ferrarisite, Ca(5)H(2)(AsO(4))(4).9H(2)O - guerinite and CaHAsO(4).H(2)O. The analytical concentrations of calcium and arsenic and pH were used in estimating solubility products. The estimated values were then refined through the comparison of the analytical data with calculated K(sp) values using the computer program PhreeqC. From the refined solubility products, the free energies of formation of the calcium arsenate hydrates were calculated as follows: Ca(4)(OH)(2)(AsO(4))(2).4H(2)O (-4941 kJ/mol), Ca(5)(AsO(4))(3)OH (-5087 kJ/mol), Ca(3)(AsO(4))(2).3 23H(2)O (-3945 kJ/mol), Ca(3)(AsO(4))(2).4 14H(2)O (-4085 kJ/mol), Ca(5)H(2)(AsO(4))(4).9H(2)O - ferrarisite (-7808 kJ/mol), Ca(5)H(2)(AsO(4))(4).9H(2)O - guerinite (-7803 kJ/mol), and CaHAsO(4).H(2)O (-1533 kJ/mol). Unlike other solubility studies on arsenate immobilization, this study was the first to consider the complete array of calcium arsenate hydrates that can form and to use the associated ions, CaAsO(4)(-), CaHAsO(4)(0) and CaH(2)AsO(4)(+) in determining their solubility products.

Journal Article↗
PubMed2000

Discrimination of Sebastes viviparus, Sebastes marinus and Sebastes mentella from Faroe Islands by chemometry of the fatty acid profile in heart and gill tissues and in the skull oil.

The composition of fatty acids in the tissue of heart, gill and skull oil of the three redfish species, Sebastes viviparus, Sebastes marinus and Sebastes mentella was determined by a chemometric method. The method consists of methanolysis of samples of the tissues and of the oils, gas chromatography of the resulting fatty acid methyl esters and multivariate statistical treatment, by principal component analysis, of the analytical data. Although the differences in fatty acid composition among the three tissues were the dominating features of the data, the three species had significantly different fatty acid profiles within each tissue, even though variation among the individuals was considerable. The fatty acid profiles appear to be species specific. The mutual relationship between S. marinus and S. mentella is closer than the relationship between either of them and S. viviparus.

Animals↗
PubMed2001

Flavonoid sequestration by the common blue butterfly Polyommatus icarus: quantitative intraspecific variation in relation to larval hostplant, sex and body size.

Common blue butterflies (Polyommatus icarus) sequester flavonoids from their larval food and store these pigments as part of their adult wing colouration. Insects were reared on 10 different diets to assess effects of host plants on variation in flavonoid sequestration in this moderately polyphagous butterfly. Rearing experiments revealed an unexpectedly large gradient in flavonoid richness, ranging from individuals with high flavonoid loads (reared on inflorescences of Medicago sativa, Trifolium repens, T. pratense) to butterflies which contained almost no such pigments (fed with foliage of M. sativa or Robinia pseudoacacia). Flavonoid sequestration was much more effective from natural hostplants than from experimentally offered diets which would not be accepted in the field. Female butterflies on average sequestered almost 60% more flavonoids than males. This sex difference was more pronounced on natural than on experimental diets. Flavonoid load was significantly and positively related to dry mass and forewing length as two important fitness correlates of butterflies. This correlation was particularly strong on experimental diets (i.e. under constraining conditions for development). On natural hostplants, in contrast, when butterflies generally were flavonoid-rich, no clear relationship between flavonoid load and size or mass emerged. Our analytical data are consistent with field results according to which females rich in UV-absorbing flavonoid wing pigments are more attractive to mate-searching males. In P. icarus, flavonoid richness might therefore increase visibility (by more effective sensory stimulation of the visual system), but could also confer information about the feeding history, and thus ontogenetically determined 'quality' of a potential mate.

Journal Article↗
PubMedDate not supplied

Alcohol and HIV risk taking among intravenous drug users.

PURPOSE: To determine if drug risk days are also alcohol use days for active injection drug users (IDUs). METHODS: Cross-sectional interview of 187 AUDIT-positive (> or = 8) active IDUs recruited between 2/98 and 10/99 from a needle exchange program (NEP) in Providence, RI. A drug risk day is defined as "using needles, cotton, or cookers after someone else had used it," measured using a 30-day Timeline Follow-Back procedure. RESULTS: The sample was 64% male, 87% white, with 85% meeting DSM-IV criteria for alcohol abuse/dependence. Of the total days analyzed (n = 5610), 25% were drug risk days; on 40% of these days, drinking also occurred. Using a generalized estimating equation (GEE) model to cluster by subject, alcohol use was associated with drug risk days (OR 1.53; 95% CI 1.2-1.9; P < .001), controlling for gender, age, race, cocaine use, number of daily injections, methadone treatment, and partner drug use. CONCLUSIONS: Using a data analytic strategy that allows examination of self-reports of behaviors on a day-to-day basis, we found that alcohol use is associated with drug risk taking behavior among IDUs. Whether alcohol use precedes or is subsequent to risky HIV behaviors remains to be determined.

Adult↗
PubMedDate not supplied

Investigations of causal pathways between PTSD and drug use disorders.

Although numerous studies have demonstrated an association between PTSD and substance use disorders, little is known about the causal nature of this relationship. In this article, we put forth and test major causal hypotheses. Specific hypotheses to be tested include self-medication of PTSD symptoms, substance users' high risk of exposure to traumatic events, and drug users' increased susceptibility to PTSD following a traumatic exposure. We also examine the possibility of an indirect pathway linking drug use disorders and PTSD via a shared vulnerability. Evidence for these causal hypotheses is evaluated using Hill's criteria for causal inference: strength, consistency, specificity, temporality, gradient, plausibility, coherence, experimental evidence, and analogy. We present data analytic strategies that exploit information about the temporal order of PTSD and drug use disorders to shed light on their causal relationship. Finally, we present findings on the PTSD/drug use disorder association from an epidemiologic study of young adults.

Adult↗
PubMed2002

Assessing tobacco beliefs among youth using item response theory models.

Successful intervention research programs to prevent adolescent smoking require well-chosen, psychometrically sound instruments for assessing smoking prevalence and attitudes. Twelve thousand eight hundred and ten adolescents were surveyed about their smoking beliefs as part of the Teenage Attitudes and Practices Survey project, a prospective cohort study of predictors of smoking initiation among US adolescents. Item response theory (IRT) methods are used to frame a discussion of questions that a researcher might ask when selecting an optimal item set. IRT methods are especially useful for choosing items during instrument development, trait scoring, evaluating item functioning across groups, and creating optimal item subsets for use in specialized applications such as computerized adaptive testing. Data analytic steps for IRT modeling are reviewed for evaluating item quality and differential item functioning across subgroups of gender, age, and smoking status. Implications and challenges in the use of these methods for tobacco onset research and for assessing the developmental trajectories of smoking among youth are discussed.

Adolescent↗
PubMed1983

Determination of chloroquine and its major metabolite in blood using perfluoroacylation followed by fused-silica capillary gas chromatography with nitrogen-sensitive detection.

Tandem fused-silica capillary gas chromatographic methods for the determination of chloroquine and its major metabolite, desethylchloroquine, are described. Method A employs a single extraction step and internal standardization to permit rapid, precise analyses for chloroquine in whole blood. Method B, employing derivatization with pentafluoropropionic anhydride, can then be applied to the extract to allow qualitative and quantitative confirmation of chloroquine and sensitive, precise quantification for desethylchloroquine. The detection limit for chloroquine in blood is 5 ng/ml by both methods; the limit for desethylchloroquine is 15 ng/ml. Excellent precision is achieved by the methodology, partly due to the use of separate internal standards for the two analytes, each internal standard being a close analogue of the corresponding analyte. Data are presented which demonstrate the increase over time of metabolite relative to unchanged chloroquine found in the blood of a volunteer undergoing a chemoprophylactic regimen of chloroquine.

Chloroquine↗
PubMed1999

Mass spectrometric analysis of neuropeptidergic systems in the human pituitary and cerebrospinal fluid.

Neuropeptidergic systems have been studied in human tissues and fluids, which include the pituitary and lumbar cerebrospinal fluid, respectively. This paper reviews the qualitative and quantitative mass spectrometric analytical data obtained from three areas of study. Methionine enkephalin (ME) and beta-endorphin (BE) were quantified in the human pituitary by liquid secondary ion mass spectrometry (LSI MS)-tandem mass spectrometry. Corresponding stable isotope-incorporated synthetic peptide internal standards were used. Proenkephalin A and proopiomelanocortin produce ME and BE, respectively. The analysis of neuropeptides in macroadenomas demonstrated a decrease in both of those neuropeptidergic systems relative to controls. An analysis of prolactin-secreting microadenomas showed an increase in the proenkephalin A system. Mass spectrometry was also used to detect opioid peptide-containing proteins in the pituitary. Enzymes that process the precursors of proenkephalin A and tachykinin (substance P) neuropeptides were studied in human lumbar cerebrospinal fluid. Electrospray ionization mass spectrometry was used to characterize the molecular mass of each peptide product.

Adenoma↗
PubMed1999

Comparative analysis of heroin and cocaine seizures.

In this brief review the analytical techniques mainly used for comparative analysis of both cocaine and heroin seizures are reported. The characterization of illicit samples is carried out by means of a variety of techniques including thin-layer chromatography, high-performance liquid chromatography, gas chromatography and capillary electrophoresis. By means of these technique it is possible to resolve some component in illicit drugs and their application for comparative analyses is described in this review. Owing to the complexity and the variability of the mixture related to the origin and manufacturing impurities a unique analytical approach based on the application of a single technique it is not sufficient to achieve the requested global characterization of the sample for comparative purposes. Generally a complete characterization is obtained focusing on the identification of minor and major components, origin and manufacturing impurities other than trace compounds such as solvent residues. Nevertheless the application of a single robust methods able to resolve any possible significant marker compounds, is still not described and there is a need for a standardized general procedure suitable for a complete cross-examination of analytical data related to comparative analyses that can be carried out at an international level.

Chromatography↗
PubMed2001

A re-examination of the mono-methoxy positional ring isomers of amphetamine, methamphetamine and phenyl-2-propanone.

Recently, tablets inscribed with the Mitsubishi 3-diamond logo, and sold as 3,4-methylenedioxymethamphetamine (MDMA), were found to contain p-methoxymethamphetamine (PMMA), a compound with MDMA-like effects. Shortly after this first submission, similarly inscribed tablets were encountered containing both PMMA and p-methoxyamphetamine (PMA). This second tablet composition has been implicated in several recent deaths in the US. Because two other positions are available for mono-methoxy substitution on the phenyl ring, it is essential that the correct identification be made for these compounds. Analytical data are supplied to enable differentiation of these ring isomers as well as the ketones that serve as their precursors.

Acetone↗
PubMed2001

Driving under the influence of alcohol and/or drugs in the Netherlands 1995-1998 in view of the German and Belgian legislation.

This study presents the test results of blood and urine samples of impaired drivers in the Netherlands between January 1995 and December 1998. In this period, the blood alcohol concentrations of 11,458 samples have been determined and 1665 blood or urine samples have been analysed for drugs. The median alcohol concentration was between 1.7 and 1.8 mg/ml blood. In 80% of the 1665 analysed samples drugs were detected. At least 42% (702/1665) of the impaired drivers were poly-drug users, with cocaine present in the most frequent combinations. In the Netherlands, the procedure to prove driving under the influence is complex. This procedure can be made more efficient and more effective by embedding the analytical test results, needed to prosecute an impaired driver, in the law. In Belgium and Germany, such laws already are in force. If we would apply the qualifications of the new Belgian law on our analytical data, 67% of the impaired drivers included in this comparison could have been prosecuted without discussion in court.

Alcoholic Intoxication↗
PubMed2001

Drugs in postmortem adipose tissues: evidence of antemortem deposition.

INTRODUCTION: Drug concentration measured in postmortem adipose tissue may or may not reflect antemortem concentration. To examine the possibility of whether the presence of basic drugs in adipose tissue is the result of postmortem change, we examined: tissues with and without livor mortis, concentration gradients within the adipose layer, and the stability of drug concentrations during the postmortem period. CASE REPORTS: Five drug-related deaths with case histories and analytical data are presented. Adipose tissues with and without livor mortis from the thigh area of the same decedent were analyzed for cocaine. The cocaine concentration of the tissue exhibiting 4+ livor was equivalent to the concentration observed in tissue without livor. Analyses of cross sections of adipose tissues containing cocaine and methamphetamine disclosed that drug concentrations were equally distributed throughout the layer, from just beneath the dermis to directly above the muscle. When morphine and temazepam concentrations were measured in adipose tissues collected from similar sites, but at different times, from the same cadaver, they remained essentially the same over 3 days (approximately 80 h). CONCLUSIONS: Since concentrations were the same in areas with and without livor mortis, the possibility of redistribution into adipose from blood or vascular channels is eliminated. The absence of a concentration gradient within the adipose layer rules out diffusion or permeation from muscle into the adipose layer, and the failure of morphine or temazepam concentration to change over time indicates that drugs in the adipose tissue are stable during the postmortem interval. Our findings support the notion that drugs identified in postmortem adipose tissue are there because of antemortem deposition and not because of any postmortem change or event.

Adipose Tissue↗
PubMedDate not supplied

Interfering basic materials in urine from racing greyhounds.

Three quinoline amines, 2-aminomethylquinoline, 2-hydroxymethylquinoline and quinaldine (2-methylquinoline), are identified in greyhound urine. These amines can interfere in the analysis of greyhound material for basic drugs. This is a special problem in ultraviolet spectrometry since their extinction coefficients are high. Reference analytical data for these quinoline amines and for six related compounds are given. The techniques used are infrared spectrometry, ultraviolet spectrometry, fluorometry, thin-layer chromatography, gas chromatography and mass spectrometry.

Amines↗
PubMed1999

Origin of blood ethanol in decomposed bodies.

Problems related to blood contamination by other postmortem fluids in decomposed bodies (DB) make the interpretation of medicolegal blood alcohol levels (B EtOH) a very difficult task. So the aim of this paper is to show the utilization of vitreous humor (VH) as the biological fluid for an unequivocal determination of ethanol origin in DB for forensic purposes. Alcohol was determined in VH, blood (chest fluid-CF) and urine (Ur) collected from 27 DB in different states of putrefaction. A simple head-space gas-chromatographic method was used. In fifteen cases alcohol was found to be of endogenous production due to its absence in VH. In the twelve remainders, alcohol was detected in VH and CF in an atypical distribution. Examining the reliable scene and historical information together with the analytical data, ethanol origin in these cases was classified: endogenous production (3 cases), ingested (2 cases), both (2 cases), contaminated plus endogenous production (3 cases) and unable to determine (2 cases). According to the results obtained it was possible to conclude that alcohol analysis in VH is fundamental for determining the origin of ethanol detected in CF of DB.

Alcohol Drinking↗
PubMed2001

A new sensitive and selective spectrophotometric method for the determination of catechol derivatives and its pharmaceutical preparations.

A sensitive and simple spectrophotometric method for the estimation of certain catechol derivatives like pyrocatechol (PCL), dopamine hydrochloride (DPH), levodopa (LDP), methyl dopa (MDP) and adrenaline (ADH) in either pure form or in its pharmaceutical formulation is described. The method is based on the interaction of diazotised p-nitro aniline (DPNA) with catechol derivatives in presence of molybdate ions in acidic medium. Absorbance of the resulting red complex is measured at 500-510 nm, respectively, and is stable for 2-10 h. The method is highly reproducible and specific for these selected catechol derivatives. The common excipients used as additives in pharmaceuticals and phenol, hydroquinone, resorcinol, pyrogallol and phloroglucinol do not interfere in the proposed method. Analytical data for determination of the pure compound is presented together with the application of the proposed method to the analysis of some pharmaceutical formulations. The results compare favourably with those of official and reported methods.

Catechols↗
PubMed2001

HPLC and GC-MS screening of Chinese proprietary medicine for undeclared therapeutic substances.

Traditional Chinese medicine includes raw medicinal materials and Chinese proprietary medicine (CPM). Despite being of natural origin, toxic effects, adulteration with synthetic therapeutic substances and even deaths had been associated with CPM. There is thus a need to develop analytical technique to rapidly screen for undeclared toxic and therapeutic substances in CPM. In this study, a high performance liquid chromatography-diode-array detection method was developed and used to screen for undeclared therapeutic substances in CPM. An ultraviolet (UV) library of 266 drugs had been compiled. Solute identification was performed by comparing the analytical data (UV spectra, retention time and relative retention time) with those of the 266 standards. Gas chromatography-mass spectrometry was used as a confirmation method. These chromatographic methods had been shown to be selective and reproducible in screening for undeclared drugs in CPM. Using the method developed, 41 CPM samples in seven categories were screened for undeclared therapeutic substances. One anti-asthmatic CPM was found to contain codeine.

Chromatography, High Pressure Liquid↗
PubMed2002

Second derivative spectrophotometric determination of trimethoprime and sulfamethoxazole in the presence of hydroxypropyl-beta-cyclodextrin (HP-beta-CD).

An easy and rapid second-derivative spectrophotometric method for the simultaneous analysis of trimethoprime (TMP) and sulfamethoxazole (SM) is described. These drugs have been used as antibacterial against a wide spectrum of organisms and combinations of these drugs are commonly used for the treatment of a variety of infections. The most advantageous approach of this method is the use of HP-beta-CD, which allows to improve the performance of the second-derivative ultraviolet spectrophotometry. For both compounds, a shift of the absorption bands and variations of their intensity were observed. The calibration graphs were linear in the concentration range of TMP (1.92-19.2 microg ml(-1)) and SM (1.60-16.5 microg ml(-1)), the correlation coefficient for the calibration graphs was better than 0.9994 and the precision was satisfactory (CV%< 4.96) in HP-beta-CD solutions. The proposed method was successfully applied to the assay of commercial tablets. The results were compared to those obtained by second-derivative ultraviolet spectrophotometry in the absence of HP-beta-CD. Thereby, the details of the statistical treatment of the analytical data are also presented.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed2002

Temperature-rate profiles by polarimetric variable-temperature kinetic experiments to study racemization reactions.

The racemization of (-)-adrenaline was followed by polarimetric variable-temperature kinetic experiments obtaining activation parameters and k(obs)(T) profile in one tenth of the time usually spent for traditional kinetic runs. A polarimeter connected to a computer for the acquisition and processing of the analytical data was used. The kinetic profiles were processed by both an integral method and a differential method. The results are in good agreement with each other and with those obtained by constant-temperature kinetics.

Drug Stability↗