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PubMed1992

The histamine content of allergen extracts.

The histamine content of 108 inhalant, food, and venom extracts from four commercial sources was measured by chemical (glass fiber-based) and immunologic (competitive RIA) methods. Histamine was present in 64 of 76 inhalant extracts (range, 0.005 to 7.4 micrograms/ml), 20 of 26 food extracts (range, 0.16 to 23 micrograms/ml), and six of six venoms, 100 micrograms/ml (range, 1.0 to 38 micrograms/ml). Histamine was removed by treatment with diamine oxidase or dialysis of an extract. Repeat assay of selected extracts after addition of known amounts of histamine in the glass fiber-based method produced additive results, and glycerin- or phenol-extract preservatives did not affect assay performance. Timed extractions of dried-pollen grains demonstrated maximal histamine content at 30 seconds, suggesting that histamine is an inherent component of at least some pollens. Histamine found in some allergen extracts could, under extreme circumstances, produce false-positive results in skin testing and in basophil histamine release assays, and could affect the result of research that uses intact pollen or allergen extracts.

Allergens↗
PubMed2004

Development of fluorinated low temperature glassy carbon films for solid-phase microextraction.

Solid-phase microextraction (SPME) fibers with supported fluorinated glassy carbon are demonstrated for the first time. Oligo[1,3-dibutadiynylene-1,3-(tetrafluoro)phenylene] was synthesized and heated to temperatures that varied from 200 to 1000 degrees C to produce the fluorinated glassy carbon. The extent of graphitization of the glassy carbon increased as the processing temperature increased. The fluorinated glassy carbon selectively extracted monohalogenated benzenes from an aqueous solution when compared to the extraction of toluene. The selectivity increased in the order of phi-F < phi-Cl < phi-Br < phi-I. The selectivity for the halogenated compounds was greatest for the fluorinated glassy carbon phase processed at temperature below approximately 400 degrees C. Preliminary studies on the retention mechanism of the LTGC phase show that dispersive interactions are very important to the retention of halocarbons on the fluorinated LTGC. Finally, the selectivity of the fluorinated LTGC for halogenated compounds was compared to that of commercially available SPME fibers, such as poly(dimethylsiloxane), poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB), and poly(dimethylsiloxane)/Carboxen (PDMS/Carboxen) fibers. As expected the fluorinated LTGC was more selectivity for the halogenated compounds. Interestingly the order of the increase in selectivity is opposite when comparing the fluorinated-LTGC and the three commercial fibers. A decrease in selectivity was observed going from fluorobenzene to iodobenzene using PDMS/DVB and PDMS/Carboxen fibers. While for the pure PDMS phase, there is a slight increase in selectivity from fluorobenzene to chlorobenzene but the remaining trend shows little change for bromobenzene and iodobenzene.

Carbon↗
PubMed2006

Speciation of 210Po and 210Pb in air particulates determined by sequential extraction.

Speciation of (210)Po and (210)Pb in air particulates of two Syrian phosphate sites with different climate conditions has been studied. The sites are the mines and Tartous port at the Mediterranean Sea. Air filters were collected during September 2000 until February 2002 and extracted chemically using different selective fluids in an attempt to identify the different forms of these two radionuclides. The results have shown that the inorganic and insoluble (210)Po and (210)Pb (attached to silica and soluble in mineral acids) portion was found to be high in both sites and reached a maximum value of 94% and 77% in the mine site and Tartous port site, respectively. In addition, only 24% of (210)Pb in air particulates was found to be associated with organic materials probably produced from the incomplete burning of fuel vehicle and similar activities. Moreover, the (210)Po/(210)Pb activity ratio in air particulates was higher than that in all samples at both sites and varied between 3.85 in November 2000 at Tartous port site and 20 in April 2001 at the mine area. These activity ratios were also higher than the natural levels. The (210)Po/(210)Pb activity ratio was also determined in each portion resulting from the selective extraction and found to be higher than that in most samples. The sources of (210)Po excess in these portions are discussed. Soil suspension, which is common in the dry climate dominant in the area, sea water spray and heating of phosphate ores were considered; polonium is more volatile than the lead compounds at even moderate temperature. Furthermore, variations in the chemical forms of (210)Po and (210)Pb during the year were also investigated. However, the results of this study can also be utilized for dose assessment to phosphate industry workers.

Air Pollutants, Radioactive↗
PubMed2006

Role of Brassica juncea (L.) Czern. (var. Vaibhav) in the phytoextraction of Ni from soil amended with fly ash: selection of extractant for metal bioavailability.

A pot experiment was carried out to study the potential of the plant of Brassica juncea for the phytoextraction of metal from fly ash amended soil and to study correlation between different pool of metals (total, DTPA, CaCl(2) and NH(4)NO(3)) and metal accumulated in the plant in order to assess better extractant for plant available metals. The results of total metal analysis in the soil revealed the presence of Cr, which was found below detection limit (BDL) in the plants. The fly ash (FA) amendments and soil samples were extracted with different extractants and the level of metal vary from one extractant to another. The regression analysis between total and extractable metals showed better regression for all the tested metals except Mn (R(2)=0.001) in DTPA extraction. Correlation coefficient between metal accumulation by the plant tissues and different pool of metals showed better correlation with DTPA in case of Fe, Zn and Ni, whereas, Cu was significantly correlated with NH(4)NO(3) and other metals (Pb, Mn) with CaCl(2). The soil analysis results revealed that the mobility and plant availability of metals (Fe, Mn, Zn, Ni) within the profiles of amended soils was influenced by the change in pH, however, Pb and Cu was not affected. The metal accumulation in total plant tissues was found in the order of Fe>Ni>Zn>Mn>Cu>Pb and its translocation was found more in upper part. The plants grown on soil amended with 25%FA have shown significant increase in plant biomass, shoot and plant height, whereas, no significant effect was observed in root length. The cluster analysis showed 10%FA behave differently on the basis of physico-chemical properties and metal behavior. Thus, it may be concluded that B. juncea can be used for phytoextraction of metals, especially Ni in fly ash amendment soil.

Biological Availability↗
PubMed2006

Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.

The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods.

Anti-Infective Agents↗
PubMed2003

Determination of polar organophosphorus pesticides in vegetables and fruits using liquid chromatography with tandem mass spectrometry: selection of extraction solvent.

A method based on liquid chromatography (LC)-mass spectrometry (MS)/MS was developed for sensitive determination of a number of less gas chromatography (GC)-amenable organophosphorus pesticides (OPs; acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion) in cabbage and grapes. For extraction, several solvents were evaluated with respect to the possibility of direct injection, matrix-induced suppression or enhancement of response, and extraction efficiency. Overall, ethyl acetate was the most favourable solvent for extraction, although a solvent switch was required. For some pesticide/matrix combinations, reconstitution of the residue after evaporation required special attention. Extracts were analysed on a C18 column with polar endcapping. The pesticides were ionised using atmospheric pressure chemical ionisation on a tandem mass spectrometer in multiple reaction monitoring mode. The final method is straightforward and involves extraction with ethyl acetate and a solvent switch to 0.1% acetic acid/water without further cleanup. The method was validated at the 0.01 and 0.5 mg/kg level, for both cabbage and grapes. Recoveries were between 80 and 101% with R.S.D. < 11% (n = 5). The limit of quantification was 0.01 mg/kg and limits of detection were between 0.001 and 0.004 mg/kg.

Chromatography, High Pressure Liquid↗
PubMed1997

Phenotypic heterogeneity in nucleotide excision repair mutants of rodent complementation groups 1 and 4.

Rodent ultraviolet light (UV)-sensitive mutant cells in complementation groups (CGs) 1 and 4 normally are known for their extraordinary (approximately 80-100 x) sensitivity to mitomycin C (MMC), although some CG1 mutants with reduced MMC sensitivity were previously reported (Stefanini et al. (1987) Cytotechnology 1, 91). We report here new CG1 and CG4 mutants with only 1.6-10 x wild-type MMC sensitivity despite low unscheduled DNA synthesis (UDS) levels. Mutant UV140, in UV CG4, has approximately 3.8 x the UV sensitivity of parental line AA8, approximately 1.6 x wild-type MMC sensitivity, wild-type X-ray and ethyl methanesulfonate (EMS) sensitivity, and is only slightly (approximately 1.4 x) hypermutable to 8-azaadenine resistance by UV light. It has moderately decreased incision of UV-damaged DNA, has moderately decreased removal of (6-4) photoproducts, and is profoundly deficient in UDS after UV. After UV, it shows abnormally decreased DNA synthesis and persistently decreased RNA synthesis. In addition a cell-free extract of this mutant displays strongly reduced nucleotide excision repair synthesis using DNA treated with N-acetoxy-acetyl-amino-fluorene (AAF). The extract selectively fails to complement extracts of group 1 and 4 mutants consistent with the notion that the affected proteins, ERCC1 and ERCC4, are part of the same complex and that mutations in one subunit also affect the other component. Mutant UV212 is a CG1 mutant with approximately 3.3 x wild-type UV and approximately 5-10 x wild-type MMC sensitivity, with profoundly deficient UDS and hypermutability (approximately 5.8 x) by UV. Mutant UV201, probably in CG1, is only slightly (approximately 1.5 x) UV-sensitive and has near wild-type (1.02X) UV mutability. These unusual group 1 and 4 mutants demonstrate that the unique UV and MMC sensitivity phenotypes displayed by these groups can be separated and support the idea that they are the result of distinct repair functions of the corresponding ERCC1 and ERCC4 genes: nucleotide excision repair for UV lesions and a separate repair pathway for removal of interstrand crosslinks.

Acetoxyacetylaminofluorene↗
PubMed2002

Selective protein extraction from Chlorobium tepidum chlorosomes using detergents. Evidence that CsmA forms multimers and binds bacteriochlorophyll a.

Chlorosomes of the photosynthetic green sulfur bacterium Chlorobium tepidum consist of bacteriochlorophyll (BChl) c aggregates that are surrounded by a lipid-protein monolayer envelope that contains ten different proteins. Chlorosomes also contain a small amount of BChl a, but the organization and location of this BChl a are not yet clearly understood. Chlorosomes were treated with sodium dodecyl sulfate (SDS), Lubrol PX, or Triton X-100, separately or in combination with 1-hexanol, and the extracted components were separated from the residual chlorosomes by ultrafiltration on centrifugal filters. When chlorosomes were treated with low concentrations of SDS, all proteins except CsmA were extracted. However, this treatment did not significantly alter the size and shape of the chlorosomes, did not extract the BChl a, and caused only minor changes in the absorption spectrum of the chlorosomes. Cross-linking studies with SDS-treated chlorosomes revealed the presence of multimers of the major chlorosome protein, CsmA, up to homooctamers. Extraction of chlorosomes with SDS and 1-hexanol solubilized all ten chlorosome envelope proteins as well as BChl a. Although the size and shape of these extracted chlorosomes did not initially differ significantly from untreated chlorosomes, the extracted chlorosomes gradually disintegrated, and rod-shaped BChl c aggregates were sometimes observed. These results strongly suggest that CsmA binds the BChl a in Chlorobium-type chlorosomes and further indicate that none of the nine other chlorosome envelope proteins are absolutely required for maintaining the shape and integrity of chlorosomes. Quantitative estimates suggest that chlorosomes contain approximately equimolar amounts of CsmA and BChl a and that roughly one-third of the surface of the chlorosome is covered by CsmA.

Bacterial Proteins↗
PubMed1999

Effects on Metal Binding of Circular NH- - -O=C Intramolecular Hydrogen Bonding in Hydrophilic Pseudocavities of p-tert-Butylcalix[4]arenes Carrying Amino Acid Moieties.

Calix[4]arenes bearing amino acid moieties were prepared by the reaction of carboxyl-protected amino acids with the acid chlorides of O-carboxymethylcalix[4]arenes. The binding ability toward metal ions was estimated by solvent extraction. These calixarenes showed selective extraction capability toward Na(+) and Ag(+) ions, which increased in the order 2a < 2b < 2d < 2c. The complexing ability was also affected by the nature of the solvents and was higher in ethyl acetate than dichloromethane. (1)H NMR studies showed that the complexation of 2c with Na(+) ion induces a change of the orientation of the amide groups from a network-like pattern with circular N-H- - -O=C intramolecular hydrogen bonding of 2c to a pattern in which carbonyl groups converge on the Na(+) ion. This change was also supported by a measurement of CD spectra.

Journal Article↗
PubMed2005

Extraction of selected heavy metals using modified clays.

In the present study, attapulgite, kaolinite, and montmorillonite KSF were modified using azeotropic distillation to condense 2-mercaptoethanol with the clay material. The resulting product was used as a coordinating agent to remove selected metal ions, e.g., copper(II), cadmium(II), silver(I), nickel(II), and lead(II) ions from standard aqueous solutions. Batch systems were used, and samples were shaken for two hours, and following filtration, metal content of the filtrate was measured by atomic absorption spectrometry. Without adjusting the pH, better than 90% of the metal ions could be removed.

Bentonite↗
PubMed2000

Comparative chemopreventive mechanisms of green tea, black tea and selected polyphenol extracts measured by in vitro bioassays.

Black tea extracts (hot aqueous, polyphenols and theaflavins) and green tea extracts (hot aqueous, polyphenols, epicatechin, epicatechin gallate, epigallocatechin and epigallocatechin gallate) were tested in nine standardized cell culture assays for comparative cancer chemopreventive properties. Most black and green tea extracts strongly inhibited neoplastic transformation in mouse mammary organ cultures, rat tracheal epithelial cells and human lung tumor epithelial cells. Nearly all tea fractions strongly inhibited benzo[a]pyrene adduct formation with human DNA. Induction of phase II enzymes, glutathione-S-transferase and quinone reductase, were enhanced by nearly all tea fractions, while glutathione was induced by only a few fractions. Ornithine decarboxylase activity was inhibited by nearly all the green tea fractions, but none of the black tea fractions. 12-O-tetradecanoylphorbol-13-acetate-induced free radicals were inhibited by most tea fractions. These results provide strong evidence of both anti-mutagenic, anti-proliferative and anti-neoplastic activities for both black and green tea extracts. Such anticancer mechanisms may well be responsible for the cancer preventive efficacies seen in both experimental and human studies.

Animals↗
PubMed1980

Radioimmunoassay for tricyclic antidepressants.

A sensitive radioimmunoassay for the determination of tricyclic antidepressants is described. The antibodies were produced in rabbits immunized with a conjugate of N-succinyl-nortriptyline and human serum albumin and they were shown to be specific for the tricyclic antidepressant group of drugs. The assay was tested for the determination of amitriptyline and nortriptyline concentrations in plasma or serum. Specificity was achieved by coupling a simple extraction procedure (based on selective extraction of amitriptyline and nortriptyline at different pH-values) to the assay. Using [3H]imipramine as the tracer the sensitivity of the assay is 3.8-18.0 nmol/l depending on whether the extraction procedure is used or not and it can be carried out with 50-200 microliter sample volumes. Because of its advantages (sensitivity, specificity, simplicity, small sample volumes, low cost) this procedure is suitable for drug monitoring both during controlled tricyclic therapy and pharmacokinetic studies.

Amitriptyline↗
PubMed2000

Screening of selected plant extracts for in vitro inhibitory activity on HIV-1 reverse transcriptase (HIV-1 RT).

Methanolic-aqueous extracts of 70 plants were investigated for their ability to inhibit HIV-1 reverse transcriptase activity in vitro. Two thirds of the extracts screened showed more than 50% inhibition. Two extracts inhibited the enzyme completely while four exhibited more than 90% inhibition. Tannins as nonspecific HIV-1 RT inhibitors were detected and removed from the extracts. The IC50 values of the most potent extracts after the removal of tannins for the HIV-1 RT inhibition are as follows: Sambucus racemosa 0.017 mg/ml and Geranium phaeum 0.067 mg/ml. Daunomycine was chosen as a standard substance in the non-radioactive immuno assay used for screening. As a result from the future isolation and characterization of these compounds, new leading structures are expectable.

Enzyme-Linked Immunosorbent Assay↗