bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymmetric Synthesis of 2‐Methoxy‐2‐methylchroman‐7‐ol in Solid‐state β ‐Cyclodextrin Complexes
Authors: TAN Ni , PAN Jia‐Hui , WANG San‐Yong , XU Fang , TAO Yi‐Wen , SHE Zhi‐Gang , LIN Yong‐Cheng
Published: April 2008

A chiral product, (+)‐2‐methoxy‐2‐methylchroman‐7‐ol, was obtained from β‐cyclodextrin (β‐CD)/1,3‐dihydroxylbenzene (complex A) and methyl vinyl ketone/β‐cyclodextrin (complex B). The reaction was carried out at room temperature in a solid state to give the desired product in 82.8% yield and 78.4% ee. Low optically active product (19.5% ee) was obtained from complex B and 1,3‐dihydroxylbenzene (A), and non‐optically active product was obtained from complex A and methyl vinyl ketone (B) under the same conditions. The structures of the inclusion compounds were elucidated by melting points, X‐ray diffraction, solid‐state 13C CP/MAS NMR (100 MHz, spin5000), and ROESY analyses. The ratios (1:1) of host‐guest in the inclusion compounds were decided by 1H NMR spectra (400 MHz). The mechanism of the solid‐state conjugated cyclic addition reaction was also discussed.
Cerium Alkoxides–Synthesis, Properties and Their Use in Michael Addition Reaction
Authors: ATHAR Taimur , REDDY K. Ravinder
Published: April 2008

Cerium(III) alkoxides served as an effective and attractive promoter for the Michael addition reaction with excellent chemical yields under mild conditions in short reaction time.
Two New Cerebrosides and Anthraquinone Derivatives from the Marine Fungus Aspergillus niger
Authors: WU Zu‐Jian , OUYANG Ming‐An , SU Ren‐Kuan , GUO Yue‐Xiong
Published: April 2008

Two new cerebrosides, asperiamide B (1) and C (2), and two known aflatoxins, averufin and nidurufin, have been isolated from a Quanzhou marine fungus Aspergillus niger (MF‐16), and the structures were elucidated by spectroscopic data and chemical means. Among the compounds 5 and 6 showed moderate activities in inhibiting multiplication of the Tobacco Mosaic Virus (TMV).
Synthesis of TiO2/Poly(styrene‐co‐divinybenzene) Nanocomposite Microspheres by Grafting Copolymerization
Authors: LI Sen , WANG Kuan , CHENG Jiang , WEN Xiu‐Fang , PI Pi‐Hui , YANG Zhuo‐Ru , LI Zhi‐Ying
Published: April 2008

Porous and nonporous nanocomposite microspheres were successfully prepared by grafting titania (TiO2) particles to poly(styrene‐co‐divinylbenzene) microsphere involving silane coupling agent 3‐glycidoxypropyltri‐methoxysilane (KH560), styrene and maleic anhydride as coupling agents. The effects of KH560 and styrene on the dispersion and amount of grafted‐titania on the surface of the microsphere (nonporous) as well as the effect of porous property of the supporting microsphere on the amount of grafted‐TiO2 within the microsphere (porous) were investigated. The results indicated that both KH560 and styrene could enhance the stability and dispersion of TiO2 particles attached to the surface of the microsphere producing grain size with diameter in the range of 30–80 nm. With nonporous microsphere styrene also increased the amount of grafted‐TiO2 particles on the microsphere from 10.4% to 20.4% as revealed by TGA. Porous nanocomposite microspheres with mean pore size of 136 nm could accommodate more TiO2 particles larger than either nonporous nanocomposite or porous nancomposite with mean pore size of 31 nm, yielding maximum of 26% by weight of grafted‐TiO2.
Strength of C–H Bonds at Nitrogen α ‐Position:Implication for Metabolic Stability of Nitrogen‐containing Drug Molecules
Authors: MENG Xiang‐Ming , ZOU Lu‐Feng , XIE Miao , FU Yao
Published: April 2008

The available experimental αC‐H BDEs of a variety of amine‐containing molecules were examined by using the G3B3 and CBS‐Q methods. The verified values were employed to benchmark and calibrate the density functional theory methods. It was found that the (U)BHandH/6‐311++G(2df, 2p)//(U)B3LYP/6‐31G(d) method was a fast and accurate method for calculating C–H BDEs at nitrogen α‐positions. By using the newly benchmarked BHandH method, the αC–H BDEs in a number of nitrogen‐containing drug molecules were calculated, where a dramatic variation of the αC–H BDEs was discovered. To understand this variation, the effects of mono‐ and double‐substitution at both carbon and nitrogen atoms on the αC‐H BDEs were systematically studied. The origin of the substitution effects was thoroughly discussed in terms of four categories of substituents.
Competitive Enzymatic Fluorescence Immunoassay for Human IgG by Using a Temperature‐Sensitive Phase Separating Polymer with Regulated Phase Transition Temperature
Authors: LIN Peng , WANG Yi‐Lei , FENG Jian‐Jun , ZOU Zhi‐Hua , YANG Qian
Published: April 2008

A new enzymatic fluorescence immunoassay for human IgG was developed using a temperature‐sensitive polymer, poly(N‐isopropylacrylamide‐co‐acrylamide) [P(NIP‐AA)], as a carrier. The lower critical solution temperature of the P(NIP‐AA) containing molar fraction of 8% for AA was 37 °C. In a competitive immunoassay, immobilized IgG and the standard IgG (or sample) competed for binding to a horseradish peroxidase labeled antibody at 33 °C in homogeneous format. After changing the temperature to separate the polymer‐immune complex, the complex precipitate was re‐dissolved and determined by coupling with the fluorescence reaction of hydrogen peroxide and p‐hydroxyphenylacetic acid. The calibration graph for human IgG was linear over the range of 100–1000 ng/mL with a detection limit of 2.0 ng/mL. The method is rapid, sensitive and simple. The immune reaction efficiency was improved. In addition, the sensitivity of this method was close to that using traditional microtitration plates as carriers. However, the assay was much faster (the assay time decreased from 100–120 to 30 min). The method has been applied to the determination of the human IgG levels in human sera with satisfactory results.
Tuning Colloidal Interactions Through Coordination Chemistry
Authors: Joubert Mathieu , In Martin
Published: April 2008

The present work addresses the question of the range and amplitude of bridging attraction that is induced between surfactant micelles functionalized with complexing groups in the presence of coordination centers. An alkylethoxylated ester phosphate (AEP) is synthesized from a non‐ionic surfactant and anchored into DTAB micelles. In the absence of any coordination center, functionalized micelles repel each other. Phase behavior, dynamic light scattering and small angle neutrons scattering (SANS) experiments show that this repulsive interaction is switched to attractive by the addition of coordination centers such as aluminum cations. The extent of the composition range of coexisting phase depends on the concentration of coordination center and on the pH. Analysis of the structure factor obtained from SANS shows that the range of attraction is determined by the molecular dimension of the chelating surfactant, while the depth can be tuned with the concentration of coordination center and the pH. The strong influence of the pH is interpreted as arising from the condensation of aluminium cations that lead to high functional polynuclear complexes.
Pressure‐Induced Emission Enhancement of a Series of Dicyanovinyl‐Substituted Aromatics: Pressure Tuning of the Molecular Population with Different Conformations
Authors: Wang Qian , Li Shayu , He Liming , Qian Yan , Li Xiuping , Sun Wenhao , Liu Min , Li Juan , Li Yi , Yang Guoqiang
Published: April 2008

A series of dicyanovinyl‐substituted aromatic compounds (Ar‐DCV; Ar=9‐anthracenyl, 1‐naphthyl, 1‐pyrenyl) with dual fluorescence are prepared, and their emission properties—when molecularly dispersed in a polymer medium—are investigated under pressure perturbation. The total emission intensity is enhanced drastically from ambient pressure up to 70 kbar. Emission 30–107 times more intense than that at ambient pressure is observed at higher pressure. In dual emission, the enhancement of the local excited state (LE state) is significantly different from that of the intramolecular charge‐transfer state (ICT state). The intensity of the ICT emission increases faster (30–370 times) than that of the LE emission (less than 20 times). In accordance with spectroscopic data, emission dynamics at different pressures, and computational studies on the molecular conformations of these compounds, a kinetic model is proposed to explain the effect of pressure on the emissive properties of the Ar‐DCV compounds from the point of view of pressure‐dependent populations of the species in the ground state.
(Thermo)dynamic Role of Receptor Flexibility, Entropy, and Motional Correlation in Protein–Ligand Binding
Authors: Baron Riccardo , McCammon J. Andrew
Published: April 2008

The binding of 2‐amino‐5‐methylthiazole to the W191G cavity mutant of cytochrome c peroxidase is an ideal test case to investigate the entropic contribution to the binding free energy due to changes in receptor flexibility. The dynamic and thermodynamic role of receptor flexibility are studied by 50 ns‐long explicit‐solvent molecular dynamics simulations of three separate receptor ensembles: W191G binding a K+ ion, W191G–2a5mt complex with a closed 190–195 gating loop, and apo with an open loop. We employ a method recently proposed to estimate accurate absolute single‐molecule configurational entropies and their differences for systems undergoing conformational transitions. We find that receptor flexibility plays a generally underestimated role in protein–ligand binding (thermo)dynamics and that changes of receptor motional correlation determine such large entropy contributions.
Selective Hydrogen Oxidation in the Presence of C3 Hydrocarbons Using Perovskite Oxygen Reservoirs
Authors: Beckers Jurriaan , Drost Ruben , van Zandvoort Ilona , Collignon Paul F. , Rothenberg Gadi
Published: April 2008

Perovskite‐type oxides, ABO3, can be successfully applied as solid “oxygen reservoirs” in redox reactions such as selective hydrogen combustion. This reaction is part of a novel process for propane oxidative dehydrogenation, wherein the lattice oxygen of the perovskite is used to combust hydrogen selectively from the dehydrogenation mixture at 550 °C. This gives three key advantages: it shifts the dehydrogenation equilibrium to the side of the desired products, heat is generated, thus aiding the endothermic dehydrogenation, and it simplifies product separation (H2O vs H2). Furthermore, the process is safer since it uses the catalysts’ lattice oxygen instead of gaseous O2. We screened fourteen perovskites for activity, selectivity and stability in selective hydrogen combustion. The catalytic properties depend strongly on the composition. Changing the B atom in a series of LaBO3 perovskites shows that Mn and Co give a higher selectivity than Fe and Cr. Replacing some of the La atoms with Sr or Ca also affects the catalytic properties. Doping with Sr increases the selectivity of the LaFeO3 perovskite, but yields a catalyst with low selectivity in the case of LaCrO3. Conversely, doping LaCrO3 with Ca increases the selectivity. The best results are achieved with Sr‐doped LaMnO3, with selectivities of up to 93 % and activities of around 150 μmol O m−2. This catalyst, La0.9Sr0.1MnO3, shows excellent stability, even after 125 redox cycles at 550 °C (70 h on stream). Notably, the activity per unit surface area of the perovskite catalysts is higher than that of doped cerias, the current benchmark of solid oxygen reservoirs.
Immunocytochemical staining of p16ink4a protein as an adjunct test in equivocal liquid‐based cytology
Authors: Shin Eun Kyoung , Lee Sa Ra , Kim Mi Kyoung , Kang Eun Ji , Ju Woong , Lee Shi Nae , Han Woon Sup , Kim Seung Cheol
Published: April 2008

For cervical cancer screening, HPV‐DNA test is expensive and is not easily available in all clinical situations. Thus, we investigated the role of p16ink4a immunostaining as another adjunct test to diagnose cervical neoplasia in equivocal liquid based cytology. Eighty‐seven patients were randomly selected for this study (3 patients with normal, 84 patients with abnormal including 24 ASCUS, 30 LSIL, and 30 HSIL). We performed p16ink4a immunostaining on ThinPrep® slide and on each case from the corresponding cervical biopsy tissues. High‐risk HPV‐DNA testing was also performed on all the subjects. We found that the immunoreactivity of p16ink4a is strongly correlated with the grade of cytologic and histologic diagnoses as well as with Hybrid Capture 2. In comparing the p16ink4a immunostaining with the Hybrid Capture 2 for accuracy of the diagnosis of CIN II/III or a higher‐grade disease in the case of ASCUS/LSIL on ThinPrep®, no significant differences were observed. Our data implies that p16ink4a immunocytochemical staining in liquid‐based cytology specimens might be used as a good adjunct test to predict cervical histology in equivocal ThinPrep® tests. Diagn. Cytopathol. 2008;36:311–316. © 2008 Wiley‐Liss, Inc.
Gardnerella vaginalis and Lactobacillus sp in liquid‐based cervical samples in healthy and disturbed vaginal flora using cultivation‐independent methods
Authors: Klomp Johanna M. , Verbruggen Banut‐Sabine M. , Korporaal Hans , Boon Mathilde E. , de Jong Pauline , Kramer Gerco C. , van Haaften Maarten , Heintz A. Peter M.
Published: April 2008

Our objective was to determine the morphotype of the adherent bacteria in liquid‐based cytology (LBC) in smears with healthy and disturbed vaginal flora. And to use PCR technology on the same fixed cell sample to establish DNA patterns of the 16S RNA genes of the bacteria in the sample. Thirty samples were randomly selected from a large group of cervical cell samples suspended in a commercial coagulant fixative “(BoonFix).” PCR was used to amplify DNA of five bacterial species: Lactobacillus acidophilus, Lactobacillus crispatus, Lactobacillus jensenii, Gardnerella vaginalis, and Mycoplasma hominis. The LBC slides were then analyzed by light microscopy to estimate bacterial adhesion. DNA of lactobacilli was detected in all cell samples. Seventeen smears showed colonization with Gardnerella vaginalis (range 2.6 × 102–3.0 × 105 bacteria/μl BoonFix sample). Two cases were identified as dysbacteriotic with high DNA values for Gardnerella vaginalis and low values for Lactobacillus crispatus. The sample with the highest concentration for Gardnerella vaginalis showed an unequivocal Gardnerella infection. This study indicates that the adherence pattern of a disturbed flora in liquid‐based cervical samples can be identified unequivocally, and that these samples are suitable for quantitative PCR analysis. This cultivation independent method reveals a strong inverse relationship between Gardnerella vaginalis and Lactobacillus crispatus in dysbacteriosis and unequivocal Gardnerella infection. Diagn. Cytopathol. 2008;36:277–284. © 2008 Wiley‐Liss, Inc.
Evaluation of performance of EUS‐FNA in preoperative lymph node staging of cancers of esophagus, lung, and pancreas
Authors: Peng H. Q. , Greenwald B. D. , Tavora F. R. , Kling E. , Darwin P. , Rodgers W. H. , Berry A.
Published: April 2008

We reviewed the cytologic and histologic diagnoses and EUS report of 77 consecutive patients who had undergone EUS‐FNA preoperative staging for esophageal, lung, and pancreatic cancers at our institution. A total of 122 EUS‐FNA lymph nodes were identified. Thirty of 77 cases had histologic follow‐up. Using surgical node staging and/or surgical resection as the reference standard, the sensitivity, specificity, accuracy, and positive and negative predictive values were 75%, 95%, 89%, 86%, and 90%, respectively, for EUS‐FNA node staging. We compared cytologically malignant and benign lymph node groups with eight EUS parameters including the total number of lymph nodes found by EUS, the shape, margin, long axis, short axis, echogenicity, location of the lymph node, and EUS tumor staging. We found that the short axis is the best EUS feature to predict malignancy. Lymph nodes found in an abdominal location in esophageal and lung cancer are likely malignant. Diagn. Cytopathol. 2008;36:290–296. © 2008 Wiley‐Liss, Inc.
Diagnostic accuracy of fine‐needle aspiration cytology of palpable breast masses: An SROC curve with fixed and random effects linear meta‐regression models
Authors: Akçil Mehtap , Karaağaoğlu Ergun , Demirhan Beyhan
Published: April 2008

We used various meta‐analytic methods to compare 25 studies describing fine‐needle aspiration (FNA) cytologic analyses performed from 1984 to 2007 on palpable breast masses. We found that in the 25 studies examined, the sensitivity ranged from 78% to 100%, the specificity ranged from 76% to 100%, and the diagnostic odds ratio (DOR) ranged from 15.83 to 33 198. The overall diagnostic accuracy was found to be as follows: 0.93 (95% CI: 0.92–0.94) for sensitivity, 0.98 (95% CI: 0.97–0.98) for specificity, and 505.209 (95% CI: 273.08–934.95) for the DOR. The overall diagnostic accuracy according to the results of summary receiving operating characteristic (SROC) curve analysis was 0.95 ± 0.0032, and the overall weighted area under the (receiving operating characteristic [ROC]) curve (AUC) was 0.99 ± 0.0014. The DOR values did not show a large variation in the various positivity threshold values. However, the results of those studies had some heterogeneity. The four covariates that were added to the standard SROC model to evaluate variations in the results of the studies were the year of publication, the number of aspirations, the percentage of insufficient material, and the study design. The relative diagnostic accuracy of studies performed after 1990 was 3.98 times higher than that of studies performed before 1990. The relative DOR (RDOR) value was also found to be statistically significant (95% CI: 1.22–13.02). That result may be attributed to the technologic improvements in diagnostic tools over the years. Although it was not statistically significant, an increase in the number of aspirations caused an increase in the RDOR of the FNA cytology (95% CI: 0.52–8.11). In contrast, increasing the percent of insufficient material caused a statistically insignificant but clinically significant decrease in the RDOR of FNA (RDOR = 0.79, 95% CI: 0.21–2.98). In conclusion, our meta‐analysis has shown that FNA cytologic analysis of palpable breast masses is highly accurate in the diagnostic differentiation of benign from malignant tumors. Diagn. Cytopathol. 2008;36:303–310. © 2008 Wiley‐Liss, Inc.
Cyst fluid cytology of cerebellar hemangioblastoma: A case report
Authors: Lallu Sharda , Naran Sarla , Palmer David , Bethwaite Peter
Published: April 2008

Hemangioblastoma, an uncommon central nervous system neoplasm, commonly located in the cerebellum and more rarely in the spinal cord. In this report, we described the cytologic features of a cerebellar hemangioblastoma in a 53‐year‐old man, present in cystic fluid obtained at cranioctomy. Cytologic preparations were characterized by well preserved, scattered dissociate, and occasional groups of stromal cells with round to oval nuclei, fine chromatin, and lacelike or granular, vacuolated eosinophilic cytoplasm with a foamy appearances. In addition, calcific material, endothelial‐like cells, blood, and macrophages were seen. The radiologic impression, cytologic features, and location led us to suggest the possibility of hemangioblastoma. Subsequent histopathological material revealed the characteristic features of hemangioblastoma. Diagn. Cytopathol. 2008;36:341–343. © 2008 Wiley‐Liss, Inc.
Cytologic findings of acquired cystic disease‐associated renal cell carcinoma: A report of two cases
Authors: Rivera Michael , Tickoo Satish K. , Saqi Anjali , Lin Oscar
Published: April 2008

Renal tumors may arise in the setting of end‐stage renal cell disease. The risk is 100 times that of the normal population with an incidence ranging from 3–7%. The most common malignant tumor to arise in the setting of acquired cystic disease of the kidney is the acquired cystic disease‐associated renal cell carcinoma (ACD‐associated RCC). The cytomorphologic features of ACD‐associated RCC, which has not been described previously, show moderately cellular specimens composed of clusters of cells with papillary configuration. The cells ranged from polygonal to columnar and contained abundant eosinophilic granular cytoplasm. The nuclei were round and centrally located, and the chromatin was finely granular with prominent central nucleoli that corresponded to Fuhrman's grade 3 nucleolar size. The main differential diagnosis is type 2 papillary renal cell carcinoma, from which it can be distinguished based on clinical findings only at this moment. Diagn. Cytopathol. 2008;36:344–347. © 2008 Wiley‐Liss, Inc.
Chromatin remodeling during mouse and human embryonic stem cell differentiation
Authors: Golob Jonathan L. , Paige Sharon L. , Muskheli Veronica , Pabon Lil , Murry Charles E.
Published: April 2008

Embryonic stem cell (ESC) differentiation is an excellent model to study chromatin changes at developmentally regulated loci. Differentiating mouse and human ESCs increase genome‐wide acetylation (euchromatic) and tri‐methylation (heterochromatic) of lysine 9 on histone H3. The Oct4 locus is euchromatic when expressed in undifferentiated ESCs and heterochromatic after differentiation. Brachyury T, a mesoderm‐specific transcription factor, is not yet expressed in undifferentiated cells, where its locus has “bivalent” tri‐methyl lysine 4 and lysine 27 modifications. During directed differentiation to pre‐cardiac mesoderm, the activated brachyury locus has high levels of tri‐methyl lysine 4 (euchromatin), switching to heterochromatin after gene silencing. Thus, ESC differentiation is accompanied by genome‐wide commitment to euchromatin or heterochromatin. Undifferentiated hESCs bivalently modify the brachyury locus, activate it to euchromatin during mesoderm induction, and subsequently repress it to heterochromatin, demonstrating, to our knowledge, the first analysis of chromatin dynamics at a locus essential for mesoderm and endoderm differentiation. Developmental Dynamics 237:1389‐1398, 2008. © 2008 Wiley‐Liss, Inc.
Straightforward Synthesis of α‐Substituted Prolines by Cross‐Metathesis
Authors: Lumini Marco , Cordero Franca M. , Pisaneschi Federica , Brandi Alberto
Published: April 2008

The synthesis of several α‐substituted N‐Boc‐protected prolines has been achieved by cross metathesis (CM) of N‐Boc‐allylproline 5 with terminal long chain alkenes and alkenes bearing hydroxy, silyloxy, ester, and O‐acetylglucosamido groups. The CM occurred with good selectivity and short reaction time under microwave heating conditions, affording yields in the range of 40–92 %. Addition of Ti(OiPr)4 as a Lewis acid allowed a slight increase of the yield in the case of alkenes with Lewis basic substituents. The CM was also successfully applied to allylproline protected with trichloroacetaldehyde 4, but the intermediate products were less practical for further deprotection and elaboration. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Efficient Route to Highly Water‐Soluble Aromatic Cyclic Hydroxamic Acid Ligands
Authors: Seitz Michael , Raymond Kenneth N.
Published: April 2008

2‐Hydroxyisoquinolin‐1‐one (1,2‐HOIQO) is a new member of the important class of aromatic cyclic hydroxamic acid ligands which are widely used in metal sequestering applications and metal chelating therapy. The first general approach for the introduction of substituents at the aromatic ring of the chelating moiety is presented. As a useful derivative, the highly water‐soluble sulfonic acid has been synthesized by an efficient route that allows general access to 1,2‐HOIQO 3‐carboxylic acid amides, which are the most relevant for applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Human germline and somatic cells have similar TP53 and Kirsten‐RAS gene single base mutation frequencies
Authors: Cole Derek N. , Carlson J. Andrew , Wilson Vincent L.
Published: April 2008

Understanding the risk of offspring inheriting rare mutations, and the frequencies at which these mutations are present in germ cells can be explored with direct analysis of human semen samples. The present work utilized the ultrasensitive PCR/RE/LCR mutation assay to detect, identify and determine the prevalence single base substitution mutations in the TP53 and KRAS genes in human sperm. Four disease‐associated base sites in the TP53 and KRAS genes, three of which are known to be heritable to live, term offspring, were studied in sperm from eleven human semen specimens. Eight of the specimens (73%) displayed single base substitution mutations, and 30% of all base sites tested were found to harbor mutations ranging in prevalence from 1 × 10−6 to 1 × 10−5 wild type sperm. These germ cell single base substitution mutation frequencies are very similar to somatic tissue TP53 and KRAS mutation frequencies. Equivalent single base mutation frequencies in both germ and somatic cells suggest that there is no unusual selection or mutation protective process operating premeiotically in the germline, and that a selection bias at the level of sperm viability, conception, early cleavage, implantation, and/or embryogenesis operates to exclude the majority of these TP53 mutations and all of the activating KRAS mutations. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Improved Comet assay for the assessment of UV genotoxicity in Mediterranean sea urchin eggs
Authors: Nahon Sarah , Charles François , Pruski Audrey M.
Published: April 2008

Gametes and embryos of broadcast spawners are exposed to a wide range of chemical and physical stressors which may alone, or in conjunction, have serious consequences on reproductive outcomes. In this study, two Mediterranean echinoid species, Paracentrotus lividus and Sphaerechinus granularis, were chosen as models to study the genotoxicity of UV radiation (UVR) on the eggs of broadcast‐spawning marine invertebrates. The single cell gel electrophoresis, or Comet assay, was successfully adapted to assess DNA strand breakage in sea urchin eggs. The results demonstrated that the genetic material of sea urchin eggs is susceptible to environmentally realistic UV exposure. The induction of DNA damage in the irradiated unfertilized eggs suggests that the previously described defense mechanisms in sea urchin eggs do not completely protect the egg's DNA against UV toxicity. Taken together, our results suggest that UV‐impairment of the genetic integrity of the eggs might have a role in postfertilization failures and abnormal embryonic development. Although both species were vulnerable to UVR, embryonic development was less dramatically impaired in P.Lividus. This observation supports the postulation that species inhabiting shallower environments possess more efficient mechanisms to overcome UV‐induced DNA alterations. The present demonstration of the utility and sensitivity of the Comet assay to evaluate DNA integrity in eggs from marine invertebrates opens new perspectives for monitoring the long‐term effects of environmental exposure on populations and for the routine screening of substances for genotoxicity in marine systems. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Cytogenetic damage in female Pakistani agricultural workers exposed to pesticides
Authors: Ali Tayyaba , Bhalli Javed A. , Rana Shahid M. , Khan Qaiser M.
Published: April 2008

Bhawalpur is a major cotton‐growing area in Pakistan. Cotton picking in Pakistan is carried out by females and as a result of the intensive use of pesticides during the growing season these females are exposed to pesticide residues in the picking season. In the present study, peripheral blood was obtained from 69 cotton pickers and 69 unexposed females and used to assess the effect of pesticide exposure on genetic damage as well as on hepatic enzymes and serum cholinesterase. The subjects were of similar average age in workers and control groups (37.55 ± 12.75 vs. 37.52 ± 13.47, P > 0.05). Average exposure time of the picker females was 10.26 ± 6.14 years. Subjects from the exposed group did not use any protective measures during their work activities. Levels of serum cholinesterase were lower, and levels of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase were higher in the exposed workers as compared with the control group (P < 0.001). The exposed group exhibited significantly increased frequencies of binucleated cells with micronuclei (12.72 ± 3.48 vs. 4.35 ± 2.44, P < 0.001) and total number of micronuclei in binucleated lymphocytes (16.51 ± 4.27 vs. 5.86 ± 3.09, P < 0.001) in comparison with subjects of the control group. The binucleated cells with micronuclei frequency also seemed to increase with age in both the groups, however, the magnitude of increase was greater in exposed group than the control. Results from the present study indicate that occupational exposure to pesticide mixtures results in cytogenetic damage in exposed females. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Genotoxic effects of p,p′‐DDT (1,1,1‐trichloro‐2,2‐bis‐(chlorophenyl)ethane) and its metabolites in Zebra mussel (D. polymorpha) by SCGE assay and micronucleus test
Authors: Binelli Andrea , Riva Consuelo , Cogni Daniele , Provini Alfredo
Published: April 2008

This is the first study to evaluate the potential genotoxicity of p,p′‐DDT (1,1,1‐trichloro‐2,2‐bis‐(chlorophenyl)ethane) and its metabolites (p,p′‐DDD and p,p′‐DDE) in the sentinel mollusc Zebra mussel (Dreissena polymorpha). DNA damage was measured using the single cell gel electrophoresis (SCGE) assay and the micronucleus test (MN test), which represent two of the more sensitive biomarkers for genotoxicity evaluation. Three different concentrations (0.1, 2, and 10 μg/L) of each compound were administered in water for 168 hr, maintaining mussels at constant laboratory conditions and collecting several specimens every 48 hr for biochemical analyses. At the same time, the bioaccumulation process and the concentration/effect relationship were checked by GC‐MS/MS analyses of mussel soft tissues. The SCGE assay results showed a clear and significant (P < 0.05) relationship between DNA injuries and tested doses for all the homologues throughout the 7‐day exposure period. The final DNA damage due to p,p′‐DDE was almost double that of the other two homologues that showed the same toxicity pattern. The micronucleus frequency analysis confirmed the genotoxicity potential of the three homologues and p,p′‐DDE showed the highest irreversible DNA damage. The capability of Zebra mussels to biotransform the administered compound in the other homologues was demonstrated by multiple regression analyses carried out between the MN frequencies and the concentrations of the different homologues in the mussel soft tissues. A greater genotoxic potential of the p,p′‐DDE with respect to the other two chemicals was revealed. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Quantitative tests for stratigraphic cyclicity
Authors: Bailey R. J. , Smith D. G.
Published: April 2008

Periodic Milankovitch (M‐) orbital forcing provides an explanation for subjectively recognized short‐term repetition of lithofacies‐‘cycles’‐in the stratigraphic record. Tests of this explanation often find no order in the lithofacies and/or no regularity in the recurrence of lithofacies. This does notdisprovethe influence of M‐forcing, but a sedimentary response in terms ofirregularM‐forced ‘cycles’ is indistinguishable from one in which repetition of facies is not M‐forced. Use of such cycles in time calibration is correspondingly suspect. Stricter,dimensionalcyclicity invokes Sander's Rule, which suggests periodicity in sedimentation, for which M‐forcing provides an obvious explanation. Time calibration on the basis of strict cyclicity thus appears more dependable. Objective tests for regular M‐forced stratigraphic cyclicity commonly depend upon spectral analyses. Such tests are not unambiguous. Bilogarithmic thickness/frequency plots derived from objective layer thickness inventories (LTI) provide an alternative. Commonly, such plots show power‐law relationships that preclude dimensional M‐cyclicities. By contrast, a model data series that perfectly encodes the M‐cyclic fluctuations in terrestrial insolation generates a strongly inflected, non‐power‐law LTI plot. Power‐law plots result where the model data series is decimated by random hiatuses, with numbers and durations tuned to M‐cycle frequencies. It seems improbable that natural data series record such tuning. The general absence of strict cyclicity in the M‐frequency range is more likely to reflect the nonlinear response of sedimentary systems to cyclic M‐forcing of insolation. Interestingly, when applied to the classically cyclic lacustrine Triassic sediments of the Newark Basin, USA, the LTI test suggests a decimated record, preserving some evidence of M‐cyclicity. Copyright © 2008 John Wiley & Sons, Ltd.
The MRI brain correlates of depressed mood, anhedonia, apathy, and anergia in older adults with and without cognitive impairment or dementia
Authors: Lavretsky Helen , Zheng Ling , Weiner Michael W. , Mungas Dan , Reed Bruce , Kramer Joel H. , Jagust William , Chui Helena , Mack Wendy J.
Published: April 2008

Objectives

We examined the magnetic resonance imaging (MRI) correlates of depressed mood, apathy, anhedonia, and anergia in older adults with and without cognitive impairment or dementia.

Methods

This analysis included 270 community‐dwelling older adults (59% male; 79% Caucasian; mean age 74.4 years) who were recruited into a multi‐center longitudinal observational study of subcortical ischemic vascular disease (SIVD).The distribution of cognitive status included: cognitively intact (38%), cognitively impaired (27%), or demented (35%). All subjects underwent MRI and 41% were classified as having subcortical lacunes. MRI measures included cortical gray and white matter volumes, lacunar volumes in subcortical white and gray matter structures, volume of white matter hyperintensities, and total hippocampal volume. Depressed mood, anhedonia, anergia, and apathy apparent at the time of assessment were assessed using a behavioral assessment Associations between neuropsychiatric symptoms and MRI variables were evaluated using logistic regression.

Results

Subjects with neuropsychiatric symptoms were more likely to be cognitively impaired or demented than those without neuropsychiatric symptoms. In multivariate models controlling for cognitive status, age, gender, and education, higher lacunar volume in white matter was independently associated with the presence of all four neuropsychiatric symptoms.

Conclusions

We report an association between the lacunar volumes in the white matter and depressed mood, anhedonia, apathy, and anergia, thus supporting the role of subcortical ischemic vascular disease in the pathogenesis of late‐life neuropsychiatric disorders. Copyright © 2008 John Wiley & Sons, Ltd.
Preeclampsia – More than a pregnancy complication
Authors: Dornhöfer Nadja , Stepan Holger
Published: April 2008

Preeclampsia and intrauterine growth restriction (IUGR) account for a major part of perinatal and maternal morbidity worldwide and are associated with increased later cardiovascular risk. Both diseases are characterized by a shallow endovascular trophoblast invasion causing a disturbed placental development and are considered as syndromes with numerous vascular, metabolic, immunological and clinical alterations. Their etiology and pathophysiological consequences remain mostly unresolved. Beside others one hypothesis favors oxidative stress as a relevant pathophysiological factor. Oxidative stress as an imbalance between free radicals and the capacity of protective antioxidant systems is thought to be a potent promoter of maternal vascular dysfunction and endothelial damage. As both pregnancy complications furthermore are associated with an increased later cardiovascular risk for mother and child, the pathobiology mediated by oxidative stress may have general and long‐term devastating influence on vascular function.

Disturbed trophoblast invasion and placental development cause an abnormal uterine perfusion in mid‐pregnancy, which is easily detectable by abdominal ultrasound and identifies women at risk for the mentioned pregnancy complications antedating their clinical manifestation. We showed that an abnormal uterine perfusion in pregnancy is characterized by a decreased maternal plasma antioxidant capacity. Even though this reduction is not related to the clinical outcome of these high‐risk pregnancies, oxidative stress and uterine perfusion are clearly pathophysiologically connected.

In this article, we focus on links between oxidative stress and uterine perfusion and possible implications for the early detection of patients at risk for preeclampsia and IUGR. This might improve our understanding of these relationships, and may become of beneficial impact for the short‐ and long‐term outcome in affected mothers and their children.
Sons of Gwalia: defrauded shareholders' claims in insolvency
Authors: Gengatharen Rasiah
Published: April 2008

The recent Australian High Court decision in Sons of Gwalia v Margaretic abolished the rule that defrauded shareholders claims should be subordinated to the claims of general creditors in insolvency. This paper examines the decision, discusses its potential implications and explores whether it should be overruled through legislative amendment. Copyright © 2008 John Wiley & Sons, Ltd.
The corporate reorganization regime under China's new enterprise bankruptcy law
Authors: Qi Lijie
Published: April 2008

This paper reviews the background of embarking on the bankruptcy law reform of China, and examines the newly introduced corporate reorganization regime under China's new Enterprise Bankruptcy Law 2006. As a patchwork of the US Chapter 11 and English Administration, China's new regime is a good law on paper with sound intention and perfect logic. But there are still many legal and institutional impediments to the new regime's utilization. For example there is a serious institutional incapacity among the judiciary, as the necessary training and organization of thousands of professionals has not started. Also of concern is the still‐unfinished process of updating and modification of related laws and accounting standards as well as their application and enforcement. Enacting a new bankruptcy law is only the first step. Copyright © 2008 John Wiley & Sons, Ltd.
Cytochrome c: a non‐invasive biomarker of drug‐induced liver injury
Authors: Miller T. J. , Knapton A. , Adeyemo O. , Noory L. , Weaver J. , Hanig J. P.
Published: April 2008

Limitations of existing biomarkers to detect liver injury in experimental animals highlight the need for additional tools to predict human toxicity. The utility of cytochrome c (cyt c) as a biomarker in serum and urine was evaluated in two rodent liver injury models. Adult Sprague–Dawley rats treated with acetaminophen or d‐galactosamine (GalN) showed dose‐ and time‐dependent histomorphological changes and TUNEL staining in liver consistent with hepatocellular necrosis, apoptosis and inflammation up to 72 h. Matching changes in serum alanine transaminase (ALT), aspartate transaminase (AST) and cyt c peaked at 24 h for either drug at the highest dose, cyt c falling rapidly at 48 hours with ALT and AST remained high. Intracellular transit of cyt c from mitochondria to the cytoplasm in damaged hepatocytes, and then to peripheral circulation, was observed by immunohistochemistry. Correlation coefficients between cyt c and serum diagnostic tests indicate the liver to be the primary source of cyt c. Urinary analysis for cyt c revealed time‐dependent increase at 6 h, peaking at 24 h in GalN‐treated rats in contrast with irregular patterns of urinary ALT and AST activity. Histological changes detected at 6 h preceded altered ALT, AST and cyt c at 12 and 18 h, respectively, in GalN‐treated rats. These studies demonstrate cyt c to be a useful indicator of hepatic injury in rodents and support its utility as a non‐invasive predictor of drug‐induced hepatotoxicity, when utilized as a potential urinary biomarker. Published in 2008 by John Wiley & Sons, Ltd.
Selective activation of NF‐κB and E2F by low concentration of arsenite in U937 human monocytic leukemia cells
Authors: Yamamoto Megumi , Hirano Seishiro , Vogel Christoph F. A. , Cui Xing , Matsumura Fumio
Published: April 2008

Arsenite has been reported to exert dose‐dependent dual effects: triggering apoptosis at relatively high concentrations, whereas inducing partial differentiation at low concentrations in leukemia cells. However, the relevant molecular mechanisms of its action at low and nonapoptotic concentrations remain to be elucidated. We examined the effect of arsenite on activation of key transcription factors in cultured U937 human monocytes/macrophages. Electrophoretic mobility shift assay (EMSA), protein/DNA array and luciferase reporter assay were used to analyze the effect of arsenite on the functional activities of transcription factors. Protein/DNA array analysis showed that activation of E2F was seen after 6‐h exposure to 1 and 10 μM arsenite. In contrast, activation of NF‐κB took place only at 1 μM arsenite, whereas 10 μM arsenite showed no recognizable effect on this nuclear transcription factor in the protein/DNA array analysis. EMSA using a NF‐κB consensus probe indicates the functional activation of RelB/p50 in the presence of 1 μM arsenite, confirming the above results. Luciferase reporter assay for NF‐κB showed activation of NF‐κB in the presence of 1 μM arsenite. Interleukin (IL)‐8 and B‐cell‐activating factor of the tumor necrosis factor family (BAFF) mRNA expression, which have been shown to be regulated through NF‐κB, were activated in the presence of 1 μM arsenite. These results support the hypothesis that the primary action of nonapoptotic concentrations of arsenite in this cell line is activation of NF‐κB, signaling as a decision maker for end results such as inflammation disease or cancer. This finding offers the possibility of providing a logical explanation for the observations made by many scientists that chronic exposure of human populations to low doses of arsenic is significantly correlated to clinical signs of inflammation in many tissues. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:136–146, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20222
Differential effect of ascorbic acid and n‐acetyl‐l‐cysteine on arsenic trioxide‐mediated oxidative stress in human leukemia (HL‐60) Cells
Authors: Yedjou Clement G. , Rogers Christian , Brown Erika , Tchounwou Paul B.
Published: April 2008

Arsenic trioxide (ATO) has been recommended for the treatment of refractory cases of acute promyelocytic leukemia (APL). Recent studies in our laboratory indicated that oxidative stress plays a key role in ATO‐induced cytotoxicity in human leukemia (HL‐60) cells. In the present investigation, we performed the MTT assay and trypan blue exclusion test for cell viability. We also performed the thiobarbituric acid test to determine the levels of malondialdehyde (MDA) production in HL‐60 cells coexposed to either ascorbic acid (AA) and ATO or to n‐acetyl‐l‐cysteine (NAC) and ATO. The results of MTT assay indicated that AA exposure potentiates the cytotoxicity of ATO in HL‐60 cells, as evidenced by a gradual increase in MDA levels with increasing doses of AA. In contrary, the addition of NAC to ATO‐treated HL‐60 cells resulted in a dose‐dependent decrease of MDA production. From these results, we conclude that the addition of the AA to ATO‐treated HL‐60 cells enhances the formation of reactive oxygen species (ROS), whereas the addition of NAC under the same experimental condition significantly (p < .05) decreases the level of ROS formation. On the basis of these direct in vitro findings, our studies provide evidence that AA may extend the therapeutic spectrum of ATO. The coadministration of NAC with ATO shows a potential specificity for tumor cells, indicating that it may not enhance the clinical outcome associated with ATO monotherapy in vivo. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:85–92, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20223
Gender divergent expression of Nqo1 in Sprague Dawley and August Copenhagen x Irish rats
Authors: Augustine Lisa M. , Fisher Craig D. , Lickteig Andrew J , Aleksunes Lauren M. , Slitt Angela L. , Cherrington Nathan J.
Published: April 2008

In the mammalian liver, there is an abundance of enzymes that function to enable the safe and efficient elimination of potentially harmful xenobiotics that are encountered through environmental exposure. A variety of factors, including gender and genetic polymorphisms, contribute to the variation between an individual system's detoxification capacity and thus its ability to protect itself against oxidative stress, cellular damage, cell death, etc. NAD(P)H:quinone oxidoreducatase 1 (Nqo1) is an antioxidant enzyme that plays a major role in reducing reactive electrophiles, thereby protecting cells from free‐radical damage and oxidative stress. The goal of this study was to determine the gender‐specific expression and inducibility of Nqo1 in the Sprague Dawley (SD) and August Copenhagen x Irish (ACI) rat strains, two strains that are commonly used in drug metabolism and drug‐induced enzyme induction, toxicity, and carcinogenesis studies. Nqo1 mRNA, protein, and activity levels were determined through 96 h in SD and ACI males and females following treatment with known Nqo1 inducers oltipraz and butylated hydroxyanisole. In the SD strain, gender dimorphic expression of Nqo1 was observed with female mRNA, protein, and activity levels being significantly higher than in males. In contrast, there were minimal differences in Nqo1 mRNA, protein, and activity levels between ACI males and females. The gender dimorphic expression of Nqo1 in the SD rats was maintained through the course of induction, with female‐induced levels greater than male‐induced levels indicating that SD females may have a greater capacity to protect against oxidative stress and thus a decreased susceptibility to carcinogens. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:93–100, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20224