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PubMed2005

Comparison of selected non-exhaustive extraction techniques to assess PAH availability in dissimilar soils.

Recently, it has become apparent that the use of total contaminant concentrations as a measure of potential contaminant exposure to plants or soil organisms is inappropriate and that bioavailability of contaminants is a better measure of potential exposure. In light of this, non-exhaustive extraction techniques are being investigated to assess their appropriateness in determining bioavailability. In this study, phenanthrene extractability using hydroxypropyl-beta-cyclodextrin (HPCD) and desorption kinetics using butan-1-ol (BuOH) were determined in three dissimilar spiked soils. The soils were extracted after 1 d, 40 d and 80 d of soil-compound contact time. The amount of phenanthrene extracted by HPCD was compared to the rapidly desorbed fraction removed by BuOH. Further experiments using the same soils and extraction methods to assess the relative extractability of phenanthrene, pyrene and benzo(a)pyrene were conducted. Overall, the extraction methods used in this study had different extraction efficiencies. Results suggest that as compound hydrophobicity increased, BuOH became a more exhaustive extractant with respect to HPCD, especially for soils with high clay and organic matter content. These results are important as they highlight differences between two contrasting non-exhaustive extraction techniques both of which have been suggested to be appropriate in the assessment of bioavailability.

Chemistry Techniques, Analytical↗
PubMed1986

Comparison and critical evaluation of six published extraction and clean-up procedures for aflatoxin M1 in liquid milk.

A practical evaluation has been carried out of six previously published extraction and clean-up methods for aflatoxin M1 in liquid milk. The procedures evaluated incorporated the most widely used stages of clean-up including solvent extraction and silica gel chromatographic clean-up, selective solvent extraction of the extracted residue, the use of deproteination prior to hydrophilic column liquid-liquid partition or solvent extraction and the use of pre-packed reversed-phase cartridges for the direct extraction of aflatoxin M1 from the milk. Analysis times for each method, recoveries and relative costs are reported together with fluorescence high-performance liquid chromatography chromatograms, obtained under identical conditions to compare the relative cleanliness of the final extracts produced by each method. A pre-packed reversed phase cartridge method was shown to be the most satisfactory in terms of speed, cost and cleanliness of the final residue.

Aflatoxin M1↗
PubMed2004

Simultaneous extraction of bromide, chloride, fluoride and sulfate from soils, waste- and building materials.

The simultaneous extraction of bromide, chloride, fluoride and sulfate was studied in soils, waste- and building materials. Acid, neutral and alkaline extractants were used; 0.01 mol l(-1) H(3)PO(4), milliQ-water and 0.01 mol l(-1) NaOH, respectively. The extracts were analysed by ion chromatography and ion selective electrode. Extracted concentrations were compared with the amount obtained by an alkaline smelt, as an approximation of the total extractable content. The results indicate that there is a significant difference in extraction behaviour between waste- and building materials and soils. Bromide and chloride were in general completely extracted from the former solid materials, but less than 10% and 50%, respectively, from soils. Fluoride is strongly bound in all investigated samples; less than 10% of the total content was extracted with any of the three extractants. The fraction of extracted sulfate varied between 4 and 87% of the total content, and was in general larger in waste- and building materials than in soils. Differences in extracted concentration between the 3 extractants occurred mainly for fluoride and sulfate. Extracted bromide was similar with all three extractants and extracted chloride showed differences for the various soil samples only. Increasing the NaOH concentration up to 1 mol l(-1) resulted mainly in an increase of extracted amount of fluoride and for soils also in extracted amounts of bromide and sulfate. Although, the results show that the composition of the solid material strongly influences the final pH of the extract and the extracted amount of investigated anions, application of Milli-Q water as an extractant might be a very fruitful option within the development of the Dutch Building Materials Decree.

Bromides↗
PubMed2000

Determination of ribavirin in serum using highly selective solid-phase extraction and high-performance liquid chromatography.

A rapid assay for determination of ribavirin in serum using solid-phase extraction (SPE), high-performance liquid chromatography (HPLC), and UV-detection was developed. The SPE uses phenylboronic acid columns with an approximately 100% recovery for ribavirin. The concentration-peak area relation was linear (r > 0.995), from 1 to 64 microM in 100 microL serum. The limit of detection was 0.1 microM. The intraassay CV was 3.2% at treatment levels (9.7 microM) and 11.5% at 0.4 microM. The method is used to monitor patients undergoing ribavirin treatment for hepatitis C (HCV). Samples from HCV-infected patients with and without renal dysfunction have been analyzed without interference of endogenous compounds. It is concluded that the method is useful for routine therapeutic drug monitoring.

Antiviral Agents↗
PubMed2006

Mixing in a square and a rectangular duct regarding selection of locations for extractive sampling of gaseous contaminants.

Tests were conducted to characterize the uniformity of velocity and tracer gas profiles in a square and a rectangular duct with respect to defining the suitability of locations for single point sampling of gaseous contaminants. Several configurations, such as a straight duct with unidirectional flow at the entrance section and straight ducts preceded by mixing elements (a 90 degrees mitered bend and double 90 degrees bends in S- and U-type configurations) were tested. Results are compared with those from circular ducts. For a straight duct of square cross section, which is not preceded by a mixing element, the coefficients of variation (COV) of tracer gas concentration at 19 duct diameters downstream of the gas release location is 143% (center release of tracer gas). COVs of velocity and tracer gas concentration in a straight square duct 9.5 duct diameters downstream of a 90 degrees mitered bend are 6% and 24.3% (top inside release), respectively, which does not meet the ANSI N13.1 limit of 20% for the tracer gas COV. In case of the rectangular duct with a 3:1 (width to height) aspect ratio, COVs of velocity and tracer gas concentration at 9 duct diameters downstream of a 90 degrees mitered bend are 29% and 62% (bottom inside release), respectively. A mixing element in a square duct comprised of two 90 degrees mitered bends in a U-configuration produces results similar to those obtained with a single 90 degrees bend. However, COVs of velocity and tracer gas concentration in a square duct 6 duct diameters downstream of an S-type double bend are 10.6% and 8.3% (top inside release), respectively, which comply with the ANSI tracer gas and velocity criteria for single point representative sampling. When mixing elements were employed in square ducts, the COV results were comparable with those of other researchers for circular ducts.

Air Pollutants, Radioactive↗
PubMed1976

Lymphocyte-differentiating hormone of bursa of fabricius.

Induction of early lymphocyte differentiation was studied in vitro in fractionated bone marrow cells of newly hatched chickens, with alloantiserums to identify newly differentiated B cells (Bu-1+) and T cells (Th-1+). Thymus extract induced selective T cell differentiation; the activity of the extract corresponds to that of thymopoietin. Bursal extract induced both B cell and T cell differentiation, but at lower concentrations B cell differentiation was always greater. This activity is ascribed to a lymphocyte-differentiating hormone of the bursa of Fabricius, for which the name bursopoietin is suggested.

Animals↗
PubMed2003

Methylxanthines for exacerbations of chronic obstructive pulmonary disease: meta-analysis of randomised trials.

OBJECTIVE: To evaluate the addition of methylxanthines to standard treatments in patients presenting with acute exacerbations of chronic obstructive pulmonary disease (COPD). DESIGN: Meta-analysis of randomised controlled trials. DATA SOURCE: The Cochrane airways review group's COPD register. Two reviewers independently selected articles for inclusion, assessed methodological quality, and extracted data. SELECTION OF STUDIES: Four trials met the inclusion criteria, with 169 patients. MAIN OUTCOME MEASURES: Mean change in spirometry, clinical end points, symptom scores, and adverse events. RESULTS: Mean change in forced expiratory volume at one second at two hours was similar in methylxanthine and placebo groups but transiently increased with methylxanthines at three days. Non-significant reductions in admissions to hospital and length of stay were offset by a non-significant increase in relapses at one week. Changes in symptom scores did not reach significance. Methylxanthines caused more nausea and vomiting than placebo (odds ratio 4.6, 95% confidence interval 1.7 to 12.6), and non-significant increases in tremor, palpitations, and arrhythmias were also observed. CONCLUSIONS: The available data do not support the use of methylxanthines for the treatment of exacerbations of chronic obstructive pulmonary disease. Potential benefits of methylxanthines for lung function and symptoms were generally not confirmed at standard levels of significance, whereas the potentially important adverse events of nausea and vomiting were significantly increased in patients receiving methylxanthines.

Administration, Oral↗
PubMed2002

Determination of V(IV) and V(V) by electrothermal atomic absorption spectrometry following selective solid-phase extraction and the study on the change in the oxidation state of vanadium species in seawater during the sample storage.

The changes in the oxidation state of vanadium in artificial and natural seawater samples were studied by electrothermal atomic absorption spectrometry (ETAAS) with a direct injection of a resin suspension. V(IV) and V(V) were extracted as the complex with Chromazurol B and with N-cinnamoyl-N-2,3-xylylhydroxylamine, respectively, using a suspension of an anion-exchange resin and determined by ETAAS independently. The detection limits of both methods were 0.02 ng ml(-1) for 40 ml of a sample solution. The recovery tests for an artificial seawater sample spiked with V(IV) and/or V(V) were carried out carefully. The results showed that the recoveries of V(IV) or V(V) were 99.2-109% and the standard deviations were 1-6%. The total V was also determined after V(V) was reduced by ascorbic acid. In artificial seawater at pH 7.8, V(V) was stable but V(IV) was oxidized rapidly. In acidified artificial seawater (pH 2.0), V(IV) was oxidized slowly but only a small tendency of such reduction of V(V) was observed. In a natural seawater sample, V(IV) was not detected. The acidification of the natural seawater sample resulted in the reduction of V(V).

Hydrogen-Ion Concentration↗
PubMed2000

Massage therapy and therapeutic touch in children: state of the science.

OBJECTIVE: To review and critique the research on the effect of massage therapy and therapeutic touch in children, and to describe clinical implications and make suggestions for future study. DATA SOURCES: Studies were obtained through online computer searches of CINAHL, MEDLINE, PsychInfo, and SocioFile. Key words used were tactile, kinesthetic, massage therapy, touch, therapeutic touch, infants, and children. STUDY SELECTION, DATA EXTRACTION, AND SYNTHESIS: Fourteen massage therapy studies were selected because they met the following 3 criteria: investigated massage therapy in children; were published in refereed nursing, allied health, or infant and child development journals between 1969 and 1999; and were quantitative in nature. Studies were divided according to developmental age for analysis: neonates, preschool, and older children. Five therapeutic touch studies, 3 quantitative and 2 qualitative, were selected because they were the only empirical reports about the effect of therapeutic touch in children to date. In addition to critiques, the therapeutic touch studies were examined for the following 10 characteristics: study purpose/hypotheses, background/literature review, sample selection method, study design/random assignment, independent variable/length of treatment/control and confounders, dependent variables/measurements, outcomes, study limitations, and implications for future research. CONCLUSIONS: More research exists to support the use of massage therapy than therapeutic touch in children. A set of common findings across 2 decades of study suggests that massage therapy may be useful in the care of infants and children. Because massage therapy and therapeutic touch seem to elicit similar parasympathetic effects, therapeutic touch may be useful. There is insufficient evidence, however, to recommend its use in children without qualifications.

Adolescent↗
PubMed2001

[Selection of optimal ultrasonic extraction process of Elaeagnus angustifolia L. by uniform design].

The influences of ultrasonic frequency, ultrasonic time and solvent content on the extraction rate of fat oil in Elaeagnus angustifolia L. were studied. The optimum extraction condition was obtained. The results showed that the ultrasonic extraction method of fat oil in Elaeagnus angustifolia L. could save time, improve extraction rate and need not be hot compared with traditional extraction method.

Elaeagnaceae↗
PubMed2006

Screening of selected Arabian medicinal plant extracts for inhibitory activity against peptidases.

The methanolic extracts of 20 medicinal plants from the island Soqotra/Yemen were screened with respect to their inhibitory potency against angiotensin converting enzyme (ACE), neutral endopeptidase (NEP) and aminopeptidase N (APN). Eight extracts did not show significant inhibitory activity against the enzymes tested, only Kalanchoe farinacea, Boswellia elongata and Cissus hamaderohensis inhibited all three enzymes. The most active extract was prepared from Kalanchoe farinacea characterized by low IC50 values especially for NEP and APN.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Selection and evaluation of sequential extraction procedures for the determination of phosphorus forms in lake sediment.

In order to achieve comparable measurements in the determination of phosphate forms in freshwater sediments, the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission has launched a project the first step of which was to select and evaluate collaboratively existing extraction procedures. This was carried out through expert consultations and a literature survey, and was followed by the organisation of a first interlaboratory study for the evaluation of four sequential extraction schemes, one of which was selected as the most promising method for achieving comparability. This scheme, a modified version of the Williams protocol, was further tested in a second interlaboratory study. The so-called SMT extraction scheme seems promising and will provide, in the near future, a valuable tool for water managers in the field of lake restoration. It will be particularly helpful in estimating the stock of P potentially available, hence the risk of eutrophication due to internal P release.

Chemistry Techniques, Analytical↗
PubMed2006

Quantitative method for analysis of monensin in soil, water, and urine by direct combination of single-drop microextraction with atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry.

A simple and selective analytical method for the quantitative determination of low concentrations of monensin in soil, surface water, and human urine has been developed. Prior to atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS) analysis, the samples were preconcentrated by using the single-drop microextraction (SDME) technique. Several factors that affect the analyte's extraction, including selection of solvent, microdrop volume, extraction time, and ionic strength, were investigated. Chloroform-toluene (1:1, v/v) was selected as the extraction solvent. Reliable results were obtained using dibenzo-30-crown-10-ether as an internal standard. The proposed method has been successfully applied for the determination of monensin in soil, surface water, and human urine spiked samples. Under the optimized conditions, the limits of quantification of the analyte in surface water, soil, and human urine were 6.7, 12.4 and 7.8 ng/mL, respectively. The intraday and interday precision variation and accuracy of the present method is within the acceptable ranges. The present method avoids the pre- and postderivatization of weak UV absorbing monensin determination using high performance liquid chromatography-ultraviolet detection (HPLC-UV). Furthermore, these techniques are time-consuming, nonreproducible at trace levels, and form undesirable products. The proposed SDME combined with AP-MALDI-MS is simple, fast, and selective for the determination of monensin in environmental and urine samples.

Humans↗