bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymorphisms in DNA repair genes, ionizing radiation exposure and risk of breast cancer in U.S. Radiologic technologists
Authors: Bhatti Parveen , Struewing Jeffery P. , Alexander Bruce H. , Hauptmann Michael , Bowen Laura , Mateus‐Pereira Lutecia H. , Pineda Marbin A. , Simon Steven L. , Weinstock Robert M. , Rosenstein Marvin , Stovall Marilyn , Preston Dale L. , Linet Martha S. , Doody Michele M. , Sigurdson Alice J. 
Published: August 2007

AbstractHigh‐dose ionizing radiation exposure to the breast and rare autosomal dominant genes have been linked with increased breast cancer risk, but the role of low‐to‐moderate doses from protracted radiation exposure in breast cancer risk and its potential modification by polymorphisms in DNA repair genes has not been previously investigated among large numbers of radiation‐exposed women with detailed exposure data. Using carefully reconstructed estimates of cumulative breast doses from occupational and personal diagnostic ionizing radiation, we investigated the potential modification of radiation‐related breast cancer risk by 55 candidate single nucleotide polymorphisms in 17 genes involved in base excision or DNA double‐strand break repair among 859 cases and 1083 controls from the United States Radiologic Technologists (USRT) cohort. In multivariable analyses, WRN V114I (rs2230009) significantly modified the association between cumulative occupational breast dose and risk of breast cancer (adjusted for personal diagnostic exposure) (p = 0.04) and BRCA1 D652N (rs4986850), PRKDC IVS15 + 6C > T (rs1231202), PRKDC IVS34 + 39T > C (rs8178097) and PRKDC IVS31 − 634C > A (rs10109984) significantly altered the personal diagnostic radiation exposure‐response relationship (adjusted for occupational dose) (p ≤ 0.05). None of the remaining 50 SNPs significantly modified breast cancer radiation dose‐response relationships. The USRT genetic study provided a unique opportunity to examine the joint effects of common genetic variation and ionizing radiation exposure on breast cancer risk using detailed occupational and personal diagnostic exposure data. The suggestive evidence found for modification of radiation‐related breast cancer risk for 5 of the 55 SNPs evaluated requires confirmation in larger studies of women with quantified radiation breast doses in the low‐to‐moderate range. © 2007 Wiley‐Liss, Inc.
Identification of novel antiangiogenic anticancer activities of deguelin targeting hypoxia‐inducible factor‐1 alpha
Authors: Oh Seung‐Hyun , Woo Jong K. , Jin Quanri , Kang Hye‐Jin , Jeong Joo‐Won , Kim Kyu‐Won , Hong Waun Ki , Lee Ho‐Young 
Published: August 2007

AbstractHypoxia‐inducible factor 1 (HIF‐1) plays an essential role in tumor angiogenesis and growth by regulating the transcription of several genes in response to hypoxic stress and changes in growth factors. This study was designed to investigate the effects of deguelin on tumor growth and angiogenesis, and the mechanisms underlying the antitumor activities of deguelin. We show here that orally administered deguelin inhibits tumor growth and blocks tumor angiogenesis in mice. Deguelin decreased expression of HIF‐1α protein and its target genes, such as VEGF, in a subset of cancer cell lines, including H1299 lung cancer cells, and vascular endothelial cells in normoxic and hypoxic conditions. Overexpression of vascular endothelial growth factor by adenoviral vector infection abolished the antiangiogenic effects of deguelin on H1299 nonsmall cell lung cancer cells. Deguelin inhibited de novo synthesis of HIF‐1α protein and reduced the half‐life of the synthesized protein. MG132, a proteasome inhibitor, protected the hypoxia‐ or IGF‐induced HIF‐1α protein from deguelin‐mediated degradation. Our findings suggest that deguelin is a promising antiangiogenic therapeutic agent in cancer targeting HIF‐1α. Considering that HIF‐1α is overexpressed in a majority of human cancers, deguelin could offer a potent therapeutic agent for cancer. © 2007 Wiley‐Liss, Inc.
Fetus with osteogenesis imperfecta presenting as increased nuchal translucency thickness in the first trimester
Authors: Hsieh Charles Tsung‐Che , Yeh Guang‐Perng , Wu Hsin‐Hung , Wu Joung‐Liang , Chou Pan‐Hsin , Lin Yueh‐Min 
Published: August 2007

AbstractType II osteogenesis imperfecta (OI) is a perinatally lethal disorder due to type I collagen abnormalities that has been diagnosed successfully in the second trimester. We report a case of type II OI that was confirmed on postmortem histology and radiography presenting as increased nuchal translucency in the first trimester. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Transient non‐viral cutaneous gene delivery in burn wounds
Authors: Steinstraesser L. , Hirsch T. , Beller J. , Mittler D. , Sorkin M. , Pazdierny G. , Jacobsen F. , Eriksson E. , Steinau H. U. 
Published: August 2007

AbstractBackgroundGene transfer to burn wounds could present an alternative to conventional and often insufficient topical and systemic application of therapeutic agents to aid in wound healing. The goals of this study were to assess and optimize the potential of transient non‐viral gene delivery to burn wounds.MethodsHaCaT cells were transfected with luciferase or β‐galactosidase transgene using either pure plasmid DNA (pDNA) or complexed with Lipofectamine 2000, FuGENE6, or DOTAP‐Chol. Expression was determined by bioluminescence and fluorescence. Forty male Sprague‐Dawley rats received naked pDNA, lipoplexes, or carrier control intradermally into either unburned skin, superficial, partial, or full‐thickness scald burn. Animals were sacrificed after 24 h, 48 h, or 7 days, and transgene expression was assessed.ResultsGene transfer to HaCaT cells showed the overall highest expression for DOTAP/Chol (77.85 ng luciferase/mg protein), followed by Lipofectamine 2000 (33.14 ng luciferase/mg protein). pDNA‐derived gene transfer to superficial burn wounds showed the highest expression among burn groups (0.77 ng luciferase/mg protein). However, lipoplex‐derived gene transfer to superficial burns and unburned skin failed to show higher expression.ConclusionsLipofectamine 2000 and DOTAP/Chol lipoplex showed significantly enhanced gene transfer, whereas no transfection was detectable for naked DNA in vitro. In contrast to the in vitro study, naked DNA was the only agent with which gene delivery was successful in experimental burn wounds. These findings highlight the limited predictability of in vitro analysis for gene delivery as a therapeutic approach. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and biological evaluation of a novel asymmetrical 99mTc‐nitrido complex of metronidazole derivative
Authors: Kong Dejing , Lu Jie , Ye Shuzhang , Wang Xuebin 
Published: August 2007

AbstractThe novel dithiocarbamate derivative of metronidazole, potassium 2‐(2‐methyl‐5‐nitro‐1H‐imidazolyl)‐ethyl‐dithiocarbamate (MNIE‐DTC), was synthesized as the pharmacophore‐containing bifunctional ligand. The corresponding asymmetrical 99mTc‐nitrido complex, expected as a tumor hypoxia marker, had been successfully obtained by the addition of the biphosphine ligand PNP5 (PNP5 = N‐ethoxethyl‐N,N‐bis[2‐(bis(3‐methoxypropyl)phosphino)ethyl]‐amine) and the dithiocarbamate ligand (MNIE‐DTC) to the 99mTc‐nitrido precursor solution at 100°C for 15 min. The radiochemical purity of the product was above 95% as measured by thin‐layer chromatography and high‐performance liquid chromatography. In vitro studies showed that the complex possessed good stability under physiological conditions. Its partition coefficient studies indicated that it was a lipophilic complex. The electrophoresis results showed that the complex was cationic. Biological evaluation of the complex [99mTcN(PNP5)(MNIE‐DTC)]+ performed in Kunming mice bearing H22 tumor showed that the complex had a moderate tumor uptake (0.57±0.06%ID/g at 1h), and the ratios of tumor/blood and tumor/muscle were 2.46 and 1.31 at 1h p.i., and reached 4.52 and 2.86 at 4h p.i., respectively. Copyright © 2007 John Wiley & Sons, Ltd.
Structural deuterium isotope effects reveal the cooperativity of polymers
Authors: Cheon Kap‐Soo , Green Mark M. 
Published: August 2007

AbstractThe signature characteristic of different kinds of polymers, synthetic and natural, is cooperativity arising from the recurring features common to all polymer structures. Cooperativity and amplification are simply different words expressing the same phenomenon leading one to expect that studies of polymers will allow small effects to be magnified, or, that is, for small effects to have surprisingly large effects on polymer properties. In the work reviewed in this short article we see this amplification at work in two different ways: (1) a synthetic polymer that forms a helical conformation but without preference for helical sense, right or left handed, is caused to take on a large excess of a single helical sense by incorporation of chiral information in surprising ways, including by forming chiral centers by deuterium substitution; (2) two polymers that mix homogeneously with each other by virtue of an unknown attractive interaction are revealed by deuterium labeling to be involved in a weak hydrogen bond between a hydrogen bound to aromatic carbon and an ethereal oxygen. Copyright © 2007 John Wiley & Sons, Ltd.
Tritium labelling and degradation studies of Dmt1‐endomorphin 2
Authors: Szemenyei Erzsébet , Tóth Géza 
Published: August 2007

AbstractTwo tritiated derivatives of Dmt1‐endomorphin 2 (Dmt1‐EM2) were prepared by the catalytic tritiodehalogenation of 3′,5′‐diiodo‐Dmt1‐EM2 and the saturation of 3,4ΔPro2‐Dmt1‐EM2, resulting in [3′,5′‐3H2]Dmt1‐EM2 and [3H2]Pro2‐Dmt1‐EM2 with specific activities of 2.88 TBq/mmol (77.8 Ci/mmol) and 1.95 TBq/mmol (52.8 Ci/mmol), respectively. 3′,5′‐Diiodo‐Dmt1‐EM2 was synthesized by the chloramine T method from Dmt1‐EM2. 3,4ΔPro2‐Dmt1‐EM2 was synthesized by using the Merrifield solid‐phase method. The distributions of the tritium in the labelled peptides were investigated by reversed‐phase high‐performance liquid chromatography after acidic hydrolysis. The stability of Dmt1‐EM2 in a rat brain membrane homogenate was also determined. Copyright © 2007 John Wiley & Sons, Ltd.
1,4‐Dihydropyridines (DHPs) – a class of very potent drugs: syntheses of isotopically labeled DHP derivatives during the last four decades
Authors: Pleiss U. 
Published: August 2007

Abstract1,4‐Dihydropyridines (DHPs) belonging to the group of calcium antagonists or calcium channel blockers' are among the most important drugs used in the treatment of cardiovascular diseases. During the development processes all candidates on the market have to be labeled with isotopes. Since the discovery of 1,4‐dihydropyridines (DHP) as cardiovascular drugs, the published syntheses for the labeling with radioactive isotopes like tritium, carbon‐11, carbon‐14, iodine‐125 and stable isotopes like deuterium and carbon‐13 are reviewed in the present report. The different synthetic routes are depicted and the synthesis details will be discussed with respect to the yields referred to labeled starting materials, specific activities and labeling degrees. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid simultaneous determination of 14 sulfonamides in wastewater by liquid chromatography tandem mass spectrometry
Authors: Ye Sai , Yao Ziwei , Na Guangshui , Wang Juying , Ma Deyi 
Published: August 2007

AbstractThis paper describes a rapid method for the determination of 14 kinds of sulfonamides (SAs) in wastewater using SPE, and LC‐MS/MS with positive ESI (ESI(+)) and selected reaction monitoring (SRM) mode. The SPE was performed on an Oasis hydrophilic‐lipophilic‐balanced (HLB) cartridge. Chromatographic separation on a C18 column was achieved using a binary eluent containing methanol and water with 0.2% formic acid. Typical recoveries of the analytes ranged from 22.3 to 87.0% at a fortification level of 100 ng/L. The LODs in wastewater except sulfathiazole (3 ng/L) could be detected and quantified at levels as low as 1 ng/L. Finally, the method was applied to water from the municipal outlet and the aquaculture wastewater effluent. Sulfamethazine (SM2), sulfamethoxypyridazine (SMP), and sulfamethoxazole (SMZ) were most frequently found in wastewater in a concentration range between 1.2 and 31.7 ng/L.
Quantitative analysis of methadone in human urine samples by microextraction in packed syringe‐gas chromatography‐mass spectrometry (MEPS‐GC‐MS)
Authors: El‐Beqqali Aziza , Abdel‐Rehim Mohamed 
Published: August 2007

AbstractA method for the simultaneous analysis of methadone in urine samples by microextraction in a packed syringe online with GC‐MS (MEPS‐GC‐MS) is described. The new method reduced the sample handling and the detection limit by two‐ to seven‐fold compared to published methods. Using a quantitation method based on the calculation of analyte concentration by comparison to an internal standard, we were able to measure methadone levels consistent with values reported for healthy individuals. The intra‐assay precisions (RSD) of the method using quality control (QC) samples at three different concentration levels were about 11–14% (n = 6). The interassay precisions (RSD) were 11–15% for methadone in urine samples (n = 18). The accuracy varied from 89 to 109% for intra‐assay (n = 6), and 97 to 107% for inter‐assay (n = 18). The regression correlation coefficients (r2) were over 0.99 in all experiments.
Optimization of the separation of chlorophenols with stepwise gradient elution in reversed phase liquid chromatography
Authors: Hadjmohammadi Mohammad Reza , Kamel Kamyar , Fatemi Mohammad Hosein 
Published: August 2007

AbstractAn optimization technique based on gradient elution was used to separate eleven chlorophenols by reversed phase liquid chromatography. The separation was based on gradient elution with a stepwise variation pattern of the volume fraction of organic modifier, φ, in the mobile phase. Initially, two‐, three‐, and four‐parameter equations which describe the dependence of ln k′ upon φ, were examined for their ability to fit the experimental data. It was found that, among these equations, the four‐parameter equation gave the best fit of the experimental data. In addition to separation optimization, a non‐linear least squares program with a grid search for initial estimates was used to determine the best variation pattern. The best variation pattern was obtained with φ1 = 0.27, φ2 = 0.39, φ3 = 0.62, t1 = 33 min, and t2 = 11 min. This pattern allowed the chromatographic separation of the chlorophenols with a good resolution and a total analysis time of 51 min. Good agreement was observed between predicted and experimental values of the retention times under optimal condition.
Improved conditions for the application of solid phase microextraction prior to HPLC–FLD analysis of anatoxin‐a
Authors: Rellán Sandra , Gago‐Martínez Ana 
Published: August 2007

AbstractSolid phase microextraction coupled with high performance liquid chromatography with fluorescence detection has been optimized and evaluated for a simple, rapid, and selective analysis of anatoxin‐a. Four kinds of fiber (100 μm polydimethylsiloxane, 60 μm polydimethylsiloxane/divinylbenzene, 50 μm Carbowax/templated resin‐100, and 85 μm polyacrylate) were evaluated for an efficient extraction of the toxin. Parameters relating to the desorption step, such as desorption mode, solvent composition, time for both static and dynamic desorption, as well as carryover, have been studied and optimized. The derivatization process was investigated using NBD‐F as derivatizing reagent. Anatoxin‐a derivative was formed when the anatoxin‐a‐loaded fiber was inserted in a vial containing 5 μL of NBD‐F. Variables affecting extraction such us ionic strength, temperature, and time have been also optimized. The results obtained showed linearity in the range of 10–2000 ng and a limit of detection of 0.29 ng/mL in river water. The presented method has been applied to different environmental samples.
An advanced solventless column test for capillary GC columns
Authors: Luong Jim , Gras Ronda , Jennings Walter 
Published: August 2007

AbstractManufacturing skills for capillary GC columns have improved to a point where the commonly used tests no longer distinguish between “adequate” and “excellent” columns. A more stringent test mixture, coupled with a more exacting procedure, was proposed for testing capillary columns in 2004. The solutes were less sterically hindered and less retained, permitting the test to be run isothermally at lower temperatures where sorptive forces are stronger. To avoid masking active sites by solvent flooding, the test used a higher boiling solvent that eluted last. This test mixture, used under the prescribed conditions, differentiated adequate from excellent columns, but removal of the late‐eluting solvent prolonged run times to as long as 1 h. The new test uses the same probes proposed in 2004, but entirely eliminates the solvent. Injections utilize a plunger‐in‐needle microvolume syringe, and the “gas saver” feature of a contemporary gas chromatograph. The latter serves as a dynamic diluter to deliver nanogram quantities of undiluted solutes to the column. The test can be conducted isothermally at a lower temperature in less than 15 min for most of the columns. This paper summarizes the analytical approach used, and presents method performance data and test results obtained on contemporary capillary columns from leading manufacturers.
Hollow‐fibre supported liquid membrane extraction for determination of fluoxetine and norfluoxetine concentration at ultra trace level in sewage samples
Authors: Zorita Saioa , Mårtensson Lennart , Mathiasson Lennart 
Published: August 2007

AbstractIn this study, a method was developed for determining the concentration of the pharmaceutical fluoxetine and its metabolite, norfluoxetine, in sewage water samples. Sample preparation was performed by hollow‐fibre supported liquid membrane (HF‐SLM) extraction with final analysis using liquid chromatography with UV detection. Several parameters were studied including type of organic solvent, sample and acceptor pH, and salt and humic acid content. The optimised method allowed determination of the analyte at the ng/L level in sewage water. A linear plot gave a correlation coefficient better than 0.991 for both analytes and resulted in limits of detection in sewage water of 11 and 12 ng/L, for fluoxetine and norfluoxetine, respectively. The enrichment factor was over 1700 for both analytes in sewage water. The repeatability and reproducibility were better than 8% and 17%, respectively. The developed methodology was used to study daily variations of fluoxetine and norfluoxetine in municipal sewage streams. Norfluoxetine has been detected for the first time in sewage water and a preliminary analysis gave average concentrations of 150 and 225 ng/L for norfluoxetine and fluoxetine, respectively.
Speciation of alkyllead in aqueous samples with application of liquid membrane probe for extraction and preconcentration
Authors: Cukrowska Ewa M. , Nsengimana Hermogène , Chimuka Luke 
Published: August 2007

AbstractLead is known to be toxic, especially in its organic forms (organolead, OL). In the environment tetraalkyllead species are rapidly degraded by sunlight and atmospheric constituents like ozone or hydroxyl radicals. Such breakdown yields the soluble forms such as trialkyllead and dialkyllead and finally ionic lead species. The liquid membrane extraction probe (LMP) device has been developed and used as an extraction and preconcentration tool for the speciation analysis of organolead compounds by GC/MS. It allows analysis of OL species at low concentrations in complicated matrices of environmental samples. The effect of pH, stirring rate, and time that influence the extraction efficiency of OL extraction by the LMP method were optimized. The transformation of tetramethyllead in aqueous media at different concentrations of major ions K+, Na+, Ca2+, Mg2+, Cl–, SO42– and the application of LMP to environmental samples are presented. It was found that degradation of tetramethyllead takes between 24 and 37 days. The detection limit (LOD) of the method for all organolead species investigated is around 4.7 μg/L, with a limit of quantitation of 15 μg/L.
Determination of alachlor, metolachlor, and their acidic metabolites in soils by microwave‐assisted extraction (MAE) combined with solid phase extraction (SPE) coupled with GC‐MS and HPLC‐UV analysis
Authors: Vryzas Zisis , Tsaboula Ageliki , Papadopoulou‐Mourkidou Euphemia 
Published: August 2007

AbstractA well‐validated analytical method based on microwave‐assisted extraction (MAE) and SPE is presented for the combined analysis of alachlor, alachlor–oxanilic acid (OXA), alachlor–ethanesulfonic acid (ESA), metolachlor, metolachlor–OXA, metolachlor–ESA residues in soils. Extraction of solutes by soil sample was carried out by MAE for 20 min at 100°C in the presence of 50 mL solution (methanol/water 50:50), the extract was subsequently passed through C18 cartidges and fractionated into two fractions, the first with parent compounds (PCs) analyzed with GC‐MS and the second one containing the metabolites analyzed with HPLC. For the SPE step, various types of sorbents (Environmental C18, tC18, Supelclean ENVI‐carb, and LiChrolut EN) have been used, and their respective advantages and disadvantages are discussed. After the method optimization, average recovery values of all solutes were > 71% in the 50–500 μg/kg fortification range with RSD <10%. The LOQ and LOD were 10–50 and 5–10 μg/kg, respectively. The method was validated with two types of soils (1 and 2.4% organic matter) and in fresh (12 h aging), intermediate (1 wk aging), and aged (1 month aging) spiked samples. Moreover, residue levels determined after field application of alachlor or metolachlor were higher when soils were processed using this method than with a comparison method based on an overnight flask shaking (FS) of soil suspension.
High‐performance liquid chromatography with sequential injection for online precolumn derivatization of some heavy metals
Authors: Burakham Rodjana , Srijaranai Supalax , Grudpan Kate 
Published: August 2007

AbstractHPLC was coupled with sequential injection (SI) for simultaneous analyses of some heavy metals, including Co(II), Ni(II), Cu(II), and Fe(II). 2‐(5‐Nitro‐2‐pyridylazo)‐5‐[N‐propyl‐N‐(3‐sulfopropyl)amino]phenol (nitro‐PAPS) was employed as a derivatizing reagent for sensitive spectrophotometric detection by online precolumn derivatization. The SI system offers an automated handling of sample and reagent, online precolumn derivatization, and propulsion of derivatives to the HPLC injection loop. The metal–nitro‐PAPS complexes were separated on a C18‐μBondapak column (3.9×300 mm2). Using the proposed SI‐HPLC system, determination of four metal ions by means of nitro‐PAPS complexes was achieved within 13 min in which the parallel of derivatization and separation were processed at the same time. Linear calibration graphs were obtained in the ranges of 0.005–0.250 mg/L for Cu(II), 0.007–1.000 mg/L for Co(II), 0.005–0.075 mg/L for Ni(II), and 0.005–0.100 mg/L for Fe(II). The system provides means for automation with good precision and minimizing error in solution handling with the RSD of less than 6%. The detection limits obtained were 2 μg/L for Cu(II) and Co(II), and 1 μg/L for Ni(II) and Fe(II). The method was successfully applied for the determination of metal ions in various samples, including milk powder for infant, mineral supplements, local wines, and drinking water.