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PubMed2005

[Application of extraction needle using selective and enhanced polymer in the analysis of samples containing poisonous material].

Low concentrations of gas components usually need to be condensed before analyzing them by gas chromatography (GC). Extraction Needle using Selective and Enhanced Polymer (EN-SEP) is a recently developed devise for condensing the components that are difficult to detect by using GC. EN-SEP consists of a needle which contains methacrylate co-polymer. Gas components are adsorbed and condensed on the polymer by passing through the needle. This paper describes the usefulness of EN-SEP in a criminal case. EN-SEP was successfully applied to condense and detect a trace of propylene glycol monomethyl ether contained in a soft drink by using gas chromatography/mass spectrometry.

Beverages↗
PubMed2006

Wavelet basis selection and feature extraction for shift invariant ultrasound foreign body classification.

This paper proposes a novel technique for automatic ultrasound non-destructive foreign body (FB) detection and classification. A signal registration process is introduced to eliminate shift variations commonly encountered in ultrasound signals. Information theory based methods are then developed for wavelet basis selection and feature extraction to facilitate robust FB classification. Probabilistic neural networks are used for FB classification. Experimental results confirm that the wavelet basis selected by the proposed method improves the FB classification accuracy. It is concluded that low order wavelet bases have better ability to distinguish classes with great similarities than their higher order counterparts, while the reverse is true for more divergent classes.

Algorithms↗
PubMed2002

Host selection as a downstream strategy: polyelectrolyte precipitation of beta-glucuronidase from plant extracts.

Host selection can be a strategy to simplify downstream processing for protein recovery. Advancing capabilities for using plants as hosts offers new host opportunities that have received only limited attention from a downstream processing perspective. Here, we investigated the potential of using a polycationic precipitating agent (polyethylenimine; PEI) to precipitate an acidic model protein (beta-glucuronidase; GUS) from aqueous plant extracts. To assess the potential of host selection to enhance the ease of recovery, the same procedure was applied to oilseed extracts of canola, corn (germ), and soy. For comparison, PEI precipitation of GUS was also evaluated from a crude bacterial fermentation broth. Two versions of the target protein were investigated--the wild-type enzyme (WTGUS) and a genetically engineered version containing 10 additional aspartates on each of the enzyme's four homologous subunits (GUSD10). It was found that canola was the most compatible expression host for use with this purification technique. GUS was completely precipitated from canola with the lowest dosage of PEI (30 mg PEI/g total protein), and over 80% of the initial WTGUS activity was recovered with 18-fold purification. Precipitation from soy gave yields over 90% for WTGUS but only 1.3-fold enrichment. Corn, although requiring the most PEI relative to total protein to precipitate (210 mg PEI/g total protein for 100% precipitation), gave intermediate results, with 81% recovery of WTGUS activity and a purification factor of 2.6. The addition of aspartate residues to the target protein did not enhance the selectivity of PEI precipitation in any of the systems tested. In fact, the additional charge reduced the ability to recover GUSD10 from the precipitate, resulting in lower yields and enrichment ratios compared to WTGUS. Compared to the bacterial host, plant systems provided lower polymer dosage requirements, higher yields of recoverable activity and greater purification factors.

Chemical Precipitation↗
PubMed1988

Selective, on-column extraction of organochlorine pesticide residues from milk.

A rapid procedure has been developed that allows a single-step, selective extraction of organochlorine pesticide (OCP) residues from milk on solid-matrix disposable columns by means of acetonitrile-saturated light petroleum. Recovery experiments were carried out on homogenized milk (3.6% fat content) spiked with an ethanolic solution of nine OCPs, viz., HCB, alpha-HCH, beta-HCH, gamma-HCH, heptachlor epoxide, dieldrin, endrin, p,p'-DDE and p,p'-DDT, at levels ranging from 0.002 mg/kg for alpha-HCH to 0.008 mg/kg for p,p'-DDT. Average recoveries of four replicates were 77% for HCB and almost quantitative (94-113%) for the other pesticides, with relative standard deviations from 2.9 to 7.3%. Coextracted fatty material amounted to about 5 mg/ml of milk before the clean-up. The described procedure also showed a satisfactory performance with milk powder. The extraction procedure requires about 60 min. The main advantages are that emulsions do not occur, several samples can be run in parallel by a single operator, reusable glassware is not needed and simple operations are required.

Animals↗
PubMed1996

Solid-phase extraction for the selective isolation of polycyclic aromatic hydrocarbons, azaarenes and heterocyclic aromatic amines in charcoal-grilled meat.

A method for the simultaneous analysis of 12 mutagenic and/or carcinogenic compounds is described; these substances belong to three different chemical groups: polycyclic aromatic hydrocarbons (PAHs), azaarenes, i.e., nitrogen-containing polycyclic aromatic hydrocarbons (PANHs), and heterocyclic aromatic amines (HAAs). The selective enrichment procedure includes coupling of solid-phase extraction (SPE) steps using diatomaceous earth, propylsulfonic acid, silica gel and octadecylsilane columns. The eluted fractions were analysed by high-performance liquid chromatography with UV and electrochemical detection. Levels measured were estimated to be 4-19 ng g-1. Peak confirmation was carried out by GC-MS for both PAHs and PANHs, and by LC with a photodiode array detector for HAAs. The method was applied to the analysis of charcoal-grilled meat and was judged to be generally applicable for detection of these mutagens at the ppb level in processed foods.

Amines↗
PubMed1993

Decreased electroconvulsive shock-induced diacylglycerols and free fatty acid accumulation in the rat brain by Ginkgo biloba extract (EGb 761): selective effect in hippocampus as compared with cerebral cortex.

The effect of Ginkgo biloba extract (EGb 761) treatment (100 mg/kg/day, per os, for 14 days) on electroconvulsive shock (ECS)-induced accumulation of free fatty acids (FFA) and diacylglycerols (DAG) was analyzed in rat cerebral cortex and hippocampus. EGb 761 reduced the FFA pool size by 33% and increased the DAG pool by 36% in the hippocampus. These endogenous lipids were unaffected in cerebral cortex. During the tonic seizure (10 s after ECS) the fast accumulation of FFA, mainly 20:4, was similar in sham- and EGb 761-treated rats, in both the cerebral cortex and hippocampus. However, further accumulation of free 18:0 and 20:4, observed in the hippocampus of sham-treated rats during clonic seizures (30 s to 2 min after ECS), did not occur in EGb 761-treated animals. The rise in DAG content triggered in the cortex and hippocampus by ECS was delayed by EGb 761 treatment from 10 s to 1 min, when values similar to those in sham animals were attained. Moreover, in the hippocampus the size of the total DAG pool was decreased by 19% during the tonic seizure. At later times, DAG content showed a faster decrease in EGb 761-treated rats. By 2 min levels of all DAG acyl groups decreased to values significantly lower than in sham animals in both cortex and hippocampus. This study shows that EGb 761 treatment affects, with high selectivity, lipid metabolism and lipid-derived second messenger release and removal in the hippocampus, while affecting to a lesser extent the cerebral cortex.

Animals↗
PubMed1994

Inhibition of cell cycle oscillation of DNA replication by a selective inhibitor of the cdc2 kinase family, butyrolactone I, in Xenopus egg extracts.

A selective inhibitor of the cdc2 kinase family, butyrolactone I, was found to inhibit the DNA replication activity of Xenopus egg extracts. When metaphase-arrested Xenopus egg extracts pretreated with butyrolactone I were released into interphase by the addition of CaCl2 at low concentrations of sperm nuclei, butyrolactone I (10 microM) prevented the oscillation of DNA replication activity to a great extent and lengthened the cell cycle. In contrast, in activated extracts which had already entered interphase, prepared from eggs activated by the calcium ionophore A23187, butyrolactone I (10 microM) had little effect on the first peak of the oscillation but reduced to less than half the second peak. These inhibitory effects of butyrolactone I on the initiation of DNA replication and mitosis in Xenopus egg extracts are probably a consequence of its previously reported inhibition of the cyclin-cdc2 kinase family.

4-Butyrolactone↗
PubMed1978

Surface tension measurements on methacrylate monomer solutions, selected solvents, and gel extracts.

The surface tensions of selected methacrylate monomer and solvent solutions were measured, and calibration curves were generated. The curves were then used to deduce the amounts of water soluble extractables in methacrylate hydrogels by measuring the surface tension of the extractant. The detectability limit (parts per 10,000) and the overall sensitivity of the method suggests its possible use as an extraction monitor test for related biomaterials.

Acrylates↗
PubMed1994

Selective solid-phase extraction of urinary 2,3-dinor-6-ketoprostaglandin F1 alpha for determination with radioimmunoassay.

This paper describes a method for selective two-step solid-phase extraction of urinary 2,3-dinor-6-ketoprostaglandin F1 alpha for reliable determination with radioimmunoassay. In the immunoreactivity profile of non-selectively extracted urine after HPLC separation, over 90% of the total 2,3-dinor-6-ketoprostaglandin F1 alpha immunoreactivity consisted of interfering material coeluting with 6-ketoprostaglandin F1 alpha and 2,3-dinor-6-ketoprostaglandin F1 alpha. Among the alkyl silica sorbents studied (methyl, butyl, octyl, and octadecyl), an efficient separation of 2,3-dinor-6-ketoprostaglandin F1 alpha from 6-ketoprostaglandin F1 alpha and the lowest immunoreactive concentration of analyte were achieved in extraction on the methyl silica sorbent by elution of 2,3-dinor-6-ketoprostaglandin F1 alpha with chloroform: hexane (85:15, v/v) from the cartridge. The proportion of specific immunoreactivity could be further increased by two-step extraction of sample on methyl silica cartridges, first at pH 3 and then at pH 10 using diethyl ether:hexane (85:15, v/v) and chloroform as eluent, respectively. After this, a high correlation was found with concentrations of samples determined by radioimmunoassay using three different antisera. A significant correlation of values was also observed between samples measured by radioimmunoassay and those measured by GC-MS. The values of 12-h excretion of 2,3-dinor-6-ketoprostaglandin F1 alpha in eight volunteers (268 +/- 204 ng/g creatinine, mean +/- SD) as well as the inhibitory effect of acetylsalicylic acid (74 +/- 12%) are in accordance with those reported in the literature. This selective extraction procedure provides a high validity in radioimmunoassay without requiring subsequent TLC or HPLC purification.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

Anti-microbial activity and anti-complement activity of extracts obtained from selected Hawaiian medicinal plants.

Selected plants having a history of use in Polynesian traditional medicine for the treatment of infectious disease were investigated for anti-viral, anti-fungal and anti-bacterial activity in vitro. Extracts from Scaevola sericea, Psychotria hawaiiensis, Pipturus albidus and Eugenia malaccensis showed selective anti-viral activity against Herpes Simplex Virus-1 and 2 and Vesicular Stomatitis Virus. Aleurites moluccana extracts showed anti-bacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, while Pipturus albidus and Eugenia malaccensis extracts showed growth inhibition of Staphylococcus aureus and Streptococcus pyogenes. Psychotria hawaiiensis and Solanum niger inhibited growth of the fungi Microsporum canis, Trichophyton rubrum and Epidermophyton floccosum, while Ipomoea sp., Pipturus albidus, Scaevola sericea, Eugenia malaccensis, Piper methysticum, Barringtonia asiatica and Adansonia digitata extracts showed anti-fungal activity to a lesser extent. Eugenia malaccensis was also found to inhibit the classical pathway of complement suggesting that an immunological basis for its in vivo activity was identified. This study has confirmed some of the ethnobotanical reports of Hawaiian medicinal plants having curative properties against infections using biological assays in vitro.

Anti-Bacterial Agents↗
PubMed2000

Comparison of an enzyme-linked immunosorbent assay (ELISA) to gas chromatography (GC)--measurement of polychlorinated biphenyls (PCBs) in selected US fish extracts.

The analysis of PCBs in fish tissues by immunoassay methods was evaluated using fish collected from a US monitoring program, the National Contaminant Biomonitoring Program of the US Department of Interior, Fish and Wildlife Service. Selected composite whole fish samples, which represented widely varying concentrations and sources of PCBs, were extracted and subjected to congener PCB analysis by gas chromatography (GC) and total PCB analysis using an ELISA (ePCBs) calibrated against technical Aroclor 1248. PCB congener patterns in these fishes were different from the patterns found in commercial Aroclors or their combinations as demonstrated by principal component analysis of normalized GC congener data. The sum of the PCB congeners measured by GC (total-PCBs) ranged from 37 to 4600 ng/g (wet weight). Concentrations of PCBs as determined by the ELISA method were positively correlated with total-PCBs and the ePCBs/total-PCBs ratios for individual samples ranged from 1 to 6. Ratios of ePCBs/total-PCBs for dilutions of Aroclors 1242, 1254, and 1260 and for matrix spikes range from 0.6 for 1242 to 2.5 for 1254 and 1260. These results suggest that higher chlorinated PCB congeners have higher affinity for the anti-PCB antibodies. Partial least squares with latent variable analysis of GC and ELISA data of selected Aroclors and fish samples also support the conclusion that ELISA derived PCB concentrations are dependent on the degree of chlorination.

Animals↗
PubMed2006

Films coated with molecular imprinted polymers for the selective stir bar sorption extraction of monocrotophos.

The flexibility and simplicity of stir bar sorption extraction (SBSE) have been combined with the selectivity of molecularly imprinted polymers (MIP). Stir bars were coated reproducible with a 180 microm film formed from a formic acid solution of nylon-6 polymer either nonimprinted or imprinted with monocrotophos. Time sorption profiles were measured for the extraction of monocrotophos from dichloromethane at the concentration of 10-200 micromol/L levels with both types of films in order to compare extraction characteristics. The results indicated that the MIP coated layer showed remarkable high affinity toward monocrotophos and equilibrium adsorption was attained rapidly (60 min) in contrast to free standing molecularly imprinted polymer in which equilibrium adsorption was normally attained after several hours. The stir bars coated with MIP films were capable of extracting four structural analogues of monocrotophos from dichloromethane solution, which suggests that both the amino group and PO part of these molecules is responsible for interaction with the imprinted polymer. Evidence was also presented by FT-IR analysis that the amide-hydrogen-bonding interaction between the MIP-coated films and monocrotophos was originated for monocrotophos recognition. To achieve selective extraction of monocrotophos from sample, stir bars coated with MIP films were washed with 10% (v/v) acetic acid/methanol and methanol. Clean extracts and yields of 95% were obtained, demonstrating the suitability of stir bar coated with MIP films for the analysis of environmental and biological samples. Compared with traditional MIP and SBSE, the MIP-coated film showed not only the high selectivity but also the rapid equilibrium adsorption.

Caprolactam↗
PubMed2006

Population development by phenotypic selection with subsequent marker-assisted selection for line extraction in cucumber (Cucumis sativus L.).

Cucumber (Cucumis sativus L.; 2n = 2x = 14) has a narrow genetic base, and commercial yield of US processing cucumber has plateaued in the last 15 years. Yield may be increased by altering plant architecture to produce unique early flowering (days to flower, DTF), female (gynoecious, GYN), highly branched (multiple lateral branching, MLB), long-fruited (length:diameter ratio, L:D) cultivars with diverse plant statures. The genetic map position of QTL conditioning these quantitatively inherited yield component traits is known, and linked molecular markers may have utility in marker-assisted selection (MAS) programs to increase selection efficiency, and effectiveness. Therefore, a base population (C0), created by intermating four unique but complementary lines, was subjected to three cycles (C1-C3) of phenotypic (PHE) mass selection for DTF, GYN, MLB, and L:D. In tandem, two cycles of marker-assisted backcrossing for these traits began with selected C2 progeny (C2S) to produce families (F1[i.e., C2S x C2S], and BC(1) [i.e., F1 x C2S]) for line extraction, and for comparative analysis of gain from selection by PHE selection, and MAS. Frequencies of marker loci were used to monitor selection-dependent changes during PHE selection, and MAS. Similar gain from selection was detected as a result of PHE selection, and MAS for MLB (approximately 0.3 branches/cycle), and L:D (approximately 0.1 unit increase/cycle) with concomitant changes in frequency at linked marker loci. Although genetic gain was not realized for GYN during PHE selection, the percentage of female flowers of plants subjected to MAS was increased (5.6-9.8% per cycle) depending upon the BC1 population examined. Selection-dependent changes in frequency were also detected at marker loci linked to female sex expression during MAS. MAS operated to fix favorable alleles that were not exploited by PHE selection in this population, indicating that MAS could be applied for altering plant architecture in cucumber to improve its yield potential.

Biomarkers↗
PubMed2000

Protective effects of Mangifera indica L. extract, mangiferin and selected antioxidants against TPA-induced biomolecules oxidation and peritoneal macrophage activation in mice.

We compared the protective abilities of Mangifera indica L. stem bark extract (Vimang) 50-250 mgkg(-1), mangiferin 50 mgkg(-1), vitamin C 100 mgkg(-1), vitamin E 100 mgkg(-1)and beta -carotene 50 mgkg(-1)against the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced oxidative damage in serum, liver, brain as well as in the hyper-production of reactive oxygen species (ROS) by peritoneal macrophages. The treatment of mice with Vimang, vitamin E and mangiferin reduced the TPA-induced production of ROS by the peritoneal macrophages by 70, 17 and 44%, respectively. Similarly, the H(2)O(2)levels were reduced by 55-73, 37 and 40%, respectively, when compared to the control group. The TPA-induced sulfhydryl group loss in liver homogenates was attenuated by all the tested antioxidants. Vimang, mangiferin, vitamin C plus E and beta -carotene decreased TPA-induced DNA fragmentation by 46-52, 35, 42 and 17%, respectively, in hepatic tissues, and by 29-34, 22, 41 and 17%, in brain tissues. Similar results were observed in respect to lipid peroxidation in serum, in hepatic mitochondria and microsomes, and in brain homogenate supernatants. Vimang exhibited a dose-dependent inhibition of TPA-induced biomolecule oxidation and of H(2)O(2)production by peritoneal macrophages. Even if Vimang, as well as other antioxidants, provided significant protection against TPA-induced oxidative damage, the former lead to better protection when compared with the other antioxidants at the used doses. Furthermore, the results indicated that Vimang is bioavailable for some vital target organs, including liver and brain tissues, peritoneal exudate cells and serum. Therefore, we conclude that Vimang could be useful to prevent the production of ROS and the oxidative tissue damages in vivo.

Animals↗
PubMed2006

Synthesis of a molecularly imprinted polymer for the selective solid-phase extraction of chloramphenicol from honey.

Solid-phase extraction (SPE) with a molecularly imprinted polymer (MIP) as sorbent has been investigated for the clean-up of the broad-spectrum bacteriostatic antibiotic chloramphenicol (CAP) in honey samples. The MIP was prepared by using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as cross-linker, chloroform as porogen and CAP as template molecule. The binding behaviour of the template CAP on the MIP was evaluated by high-performance liquid chromatography, and then the MIP was applied as a sorbent in SPE to selectively extract CAP from honey. It was shown that recoveries of nearly 100% of a CAP standard solution and up to 94% from spiked honey samples could be obtained after SPE.

Chloramphenicol↗
PubMed2001

Selective solid-phase extraction of bio- and environmental samples using molecularly imprinted polymers.

Of the many applications of molecular imprinting in analytical separation science, the one with highest potential of soon being used in routine analysis is that of solid-phase extraction. Already several examples of selective pre-concentration of biological and environmental samples have been reported. The interest in imprinted extraction sorbents originates from the high selectivities and affinities obtainable, properties which can be qualitatively and quantitatively pre-determined for a particular analyte and separation by the imprinting process. This review summarises work published on molecular imprinted solid-phase extraction and discusses some imprinted-sorbent specific method development issues.

Chromatography, Gas↗
PubMed2006

Influence of suspended clay minerals and humic matter on the solid phase extraction efficiency of selected pesticides from water.

The purpose of this investigation was to determine the influence of humic acids (HA) and Ca-montmorillonite (CaM) on the solid-phase extraction (SPE) efficiency of atrazine, alachlor and alpha-cypermethrin from water samples at various pH-values. The nature and intensity of binding of the studied pesticides to CaM were determined by X-ray diffraction analysis and termogravimetric analysis (TGA) test. The studied pesticides eluted from discs were analysed by thin-layer chromatography (TLC). The effects of CaM and humic acid were generally pH-dependent and acted independently in extraction efficiency influence. Lower recovery of pesticides was observed at higher pH values when CaM was > or =0.1 g and was attributed to greater dispersion of clay, increased surface area and subsequent adsorption. Concentrations of dissolved organic carbon (DOC) in humic acid had less effect on the extraction efficiency when water was at pH 8 compared to water at pH 2, which was probably due to greater nonpolar interactions of the pesticides to the charge-neutralized humic acid molecule.

Acetamides↗
PubMed2002

Selective solid-phase extraction sorbent for caffeine made by molecular imprinting.

A molecularly imprinted polymer (MIP) was prepared with caffeine as the template molecule. Thermal polymerisation (60 degrees C) was optimised, varying ratios of monomer, cross linker and template. The polymer was used as a solid-phase extraction (SPE) sorbent, for selective trapping and pre-concentration of caffeine. Caffeine was loaded on the MIP-SPE cartridge using different loading conditions (solvents, pH value). Washing and elution of the caffeine bound to the MIP was studied utilising different protocols. The extraction protocol was successfully applied to the direct extraction of caffeine from beverages and spiked human plasma.

Beverages↗