bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoselective Routes for the Total Synthesis of (+)‐Cryptocarya Diacetate
Authors: Sabitha Gowravaram , Reddy Nandyala M. , Prasad Muddala N. , Yadav Jhillu S. 
Published: May 2009

Abstractmagnified imageA stereoselective total synthesis of (+)‐cryptocarya diacetate (1) was achieved by two different routes (Schemes 2 and 3). The sequences involve LiAlH4/LiI reduction, ring‐closing metathesis, Prins cyclization, Wacker oxidation, and Wittig olefination reactions as key steps.
Two New Quinoline Alkaloid Mannopyranosides from Solidago canadensis
Authors: Li Ying‐Ke , Zhao Qing‐Jie , Hu Jiang , Zou Zui , He Xing‐Ying , Yuan Hong‐Bin , Shi Xue‐Yin 
Published: May 2009

Abstractmagnified imageTwo novel quinoline alkaloid β‐D‐mannopyranosides, named dictamnine‐7‐β‐D‐mannopyranoside (1) and 8‐methoxydictamnine‐7‐β‐D‐mannopyranoside (2), were isolated from the whole plant of Solidago canadensis. Their structures were identified on the basis of a spectroscopic analysis.
Convenient Access to β‐Substituted Chiral Phenones
Authors: Cao Xiu‐Fang , Hu Ming , Li Fei , Lu Wen‐Chang , Yu Guang‐Ao , Liu Sheng‐Hua 
Published: May 2009

Abstractmagnified imageA highly enantioselective approach towards the synthesis of β‐substituted chiral ketones by utilizing Grignard reagents was achieved. The (R)‐ and (S)‐antipodes of the target chiral ketones 2a–2k were obtained with up to 100% ee from chiral N‐alkanoylcamphorsultams 1 (Scheme, Table 2). This simple, catalyst‐free, direct procedure for the formation of chiral ketones is a fascinating method for the practical syntheses of chiral synthons as valuable building blocks and important medicinal intermediates.
Stereoselective Synthesis of cis‐ and trans‐3,4‐Dihydro‐3,4,8‐trihydroxynaphthalen‐1(2H)‐one
Authors: Couché Emmanuel , Fkyerat Abdellatif , Tabacchi Raffaele 
Published: May 2009

Abstractmagnified imageA short and efficient protocol for the stereoselective synthesis of racemic trans‐ and cis‐3,4‐dihydro‐3,4,8‐trihydroxynaphthalen‐1(2H)‐one (1 and 2, resp.), is described, comprising nine and eight steps starting from commercial juglone (=5‐hydroxynaphthalene‐1,4‐dione; 12) (Scheme 4). Furthermore, an attempt to obtain 1 and 2 via phthalide annulation as the key step (Schemes 2 and 3) and a regioselective oxidation of the intermediate 1,2,3,4‐tetrahydronaphthalene‐1,2,4,5‐tetrols 27 and 28 with activated MnO2 were carried out (Scheme 4).
Nitrogen‐Rich Salts Based on the Energetic 5,5′‐(Hydrazine‐1,2‐diyl)bis[1H‐tetrazolide] Anion
Authors: Eberspächer Moritz , Klapötke Thomas M. , Miró Sabaté Carles 
Published: May 2009

Abstractmagnified imageThe reaction of 5,5′‐(hydrazine‐1,2‐diyl)bis[1H‐tetrazole] (HBT) with N‐bases yielded a new family of energetic N‐rich salts based on the 5,5′‐(hydrazine‐1,2‐diyl)bis[1H‐tetrazol‐1‐ide] anion with ammonium (see 1), hydrazinium (see 2), guanidinium (see 3), and aminoguanidinium (see 4) cations (5,5′‐(hydrazine‐1,2‐diyl)bis[1H‐tetrazol‐1‐ide]=5,5′‐(hydrazine‐1,2‐diyl)bis[tetrazolate]). All compounds were characterized by analytical and spectroscopic methods, and the crystal structure of 1 was determined by X‐ray analysis (triclinic, P$\bar 1$). (Carboxyamino)guanidine betaine monohydrate (=2‐(aminoiminomethyl)hydrazinecarboxylic acid hydrate (1 : 1); 5) was obtained as a by‐product in the synthesis of 4 and was characterized by X‐ray analysis (monoclinic, P21/c). Differential‐scanning calorimetric (DSC) measurements were used to assess the thermal behavior of the energetic salts 1–4, and bomb calorimetry allowed us to determine the experimental constant‐volume energies of formation $\rm{(\Delta _{\rm{c}} U_{\exp} )}$. In addition, the detonation parameters (pressure and velocity) were calculated from the energies of formation (back‐calculated from $\rm{\Delta _{\rm{c}} U_{\exp} }$) with the EXPLO5 code, and their validity was checked by comparison with the results obtained from theoretical constant‐volume energies of formation $\rm{(\Delta _{\rm{c}} U_{{\rm{pred}}} )}$ obtained by means of quantum‐chemical calculation (MP2) of electronic energies and an approximation of lattice enthalpy. Lastly, the sensitivity to shock, friction, and electrostatic discharge of 1–4 was measured by submitting the compounds to standard tests, and the ICT code was used to predict the products formed upon decomposition of the salts.
Comparison of DNA Complex Formation Behaviour for Two Closely Related Lexitropsin Analogues
Authors: Parkinson John A. , Khalaf Abedawn I. , Anthony Nahoum G. , MacKay Simon P. , Suckling Colin J. , Waigh Roger D. 
Published: May 2009

Abstractmagnified imageTwo closely related lexitropsin analogues that differ only in the form of the ‘headgroup’ functionality (CHO (for 1) vs. Ac (for 2)) have been studied in their DNA‐binding capacity for the sequence d(GCATATATGC) using 1H‐NMR spectroscopy. DNA‐Complex formation for the CHO derivative was apparent from the observation of new NMR signals on titration of DNA with ligand. Detailed investigation and assignment of the data for a ligand/DNA‐duplex ratio of 2 : 1 clearly delineated the structure as one associated with the ‘minor groove’ class of DNA complexes. The structure of the complex was determined on the basis of the acquired NMR data. Features characteristic of typical 2 : 1 minor‐groove complexes were apparent. In a similar experimental approach, the Ac analogue ligand–DNA binding response was investigated. Despite the close similarity in chemical structure to the CHO case, the Ac analogue was found to produce NMR data of a much poorer quality. This was attributed to more rapid on/off chemical exchange equilibrium between ligand and DNA. From close analysis and comparison of the NMR data for the ‘Ac’ and ‘CHO’ headgroup ligand–DNA complexes, it was possible to ascertain that the same type of complex formed in each case but with different relative binding constants. Consideration of the nature and form of these complexes has been made with reference to a previously determined structure from our laboratory for the related lexitropsin analogue thiazotropsin A.
Two New Secolignans from the Roots of Urtica fissa E. Pritz
Authors: Ji Bao‐Quan , Yan Xing‐Guo , Duan Li‐Xin , Tang Ling , Shi Li‐Ying , Wang Yong‐Qi , Feng Bao‐Min 
Published: May 2009

Abstractmagnified imageTwo new secolignans, {(3S,4S)‐4‐[bis(4‐hydroxy‐3‐methoxyphenyl)methyl]‐2‐oxotetrahydrofuran‐3‐yl}methyl β‐D‐glucopyranoside (1) and its stereoisomer {(3S,4R)‐4‐[bis(4‐hydroxy‐3‐methoxyphenyl)methyl]‐2‐oxotetrahydrofuran‐3‐yl}methyl β‐D‐glucopyranoside (2), have been isolated from the roots of Urtica fissa E. Pritz. Their structures were determined based on spectroscopic methods (HR‐MS, 1D‐ and 2D‐NMR, HMBC, HSQC, and NOESY).
Simple and Efficient Friedel–Crafts Alkylation of 1H‐Indole with Electron‐Deficient Alkenes Promoted by Zinc Acetate
Authors: Meshram Harshadas Mitaram , Kumar Dachepally Aravind , Reddy Bandi Chennakesava 
Published: May 2009

Abstractmagnified imageAn efficient method for the Friedel–Crafts alkylation of 1H‐indole with nitro alkenes in the presence of zinc acetate is described. The procedure is applicable to a variety of nitro alkenes and substituted indoles, and the yields are very high.
Unexpected Kinetics in the Polymerization of Ethene by Cp$\rm{ {_{2}^{{\ast}}}}$ZrCl2/MAO
Authors: di Lena Fabio , Chen Peter 
Published: May 2009

AbstractA sterically hindered metallocene catalyst, Cp$\rm{ {_{2}^{{\ast}}}}$ZrCl2 activated with methylaluminoxane (MAO), is found to polymerize ethene at temperatures up to 60° with a good propagation rate constant but low number of active sites, and with negligible β‐hydride elimination or β‐hydride transfer to monomer. Moreover, transmetalation to Al is found to be effectively irreversible for alkyl groups larger than Me. With the major mechanisms for chain transfer and termination suppressed, one might expect a living polymerization. The bulk polymerization of ethene was indeed found to be quasi‐living even when performed at well above room temperature, and furthermore provided rate constants which agreed remarkably well with those from the mass‐spectrometric study.
Hydrological modelling of the Kangsabati river under changed climate scenario: case study in India
Authors: Dhar Sujana , Mazumdar Asis 
Published: May 2009

AbstractIndia is a large developing country with nearly two‐thirds of the population depending directly on the climate‐sensitive sectors such as agriculture, fisheries and forests. A very well‐calibrated Soil and Water Assessment Tool (R2 = 0·9968, NSE = 0·91) was exercised over the Kangsabati river watershed in Bankura district of West Bengal, India, for a year including monsoon and non‐monsoon period in order to evaluate projected parameters for agricultural activities. Evapotranspiration, transmission losses, potential evapotranspiration and lateral flow to reach are evaluated from the years 2041–2050 in order to generate a picture for sustainable development of the river basin and its inhabitants. The projected climate change under various scenarios is likely to have implications on food production, water supply, biodiversity and livelihoods. India has a significant stake in scientific advancement as well as an international understanding to promote mitigation and adaptation. This requires improved scientific understanding, capacity building, networking and broad consultation processes. This paper is a commitment towards the planning, management and development of the water resources of the Kangsabati river by presenting detailed future scenarios of the Kangsabati river basin over the mentioned time period. The major findings of this paper were that of all the chosen projected parameters, transmission losses, soil water content, potential evapotranspiration, evapotranspiration and lateral flow to reach, display an increasing trend over the time period of years 2041–2050. Copyright © 2009 John Wiley & Sons, Ltd.
Immunization with a P53 synthetic long peptide vaccine induces P53‐specific immune responses in ovarian cancer patients, a phase II trial
Authors: Leffers Ninke , Lambeck Annechien J.A. , Gooden Marloes J.M. , Hoogeboom Baukje‐Nynke , Wolf Rinze , Hamming Ineke E. , Hepkema Bouke G. , Willemse Pax H.B. , Molmans Barbara H.W. , Hollema Harry , Drijfhout Jan W. , Sluiter Willem J. , Valentijn A. Rob P.M. , Fathers Loraine M. , Oostendorp Jaap , van der Zee Ate G.J. , Melief Cornelis J. , van der Burg Sjoerd H. , Daemen Toos , Nijman Hans W. 
Published: May 2009

AbstractThe prognosis of ovarian cancer, the primary cause of death from gynecological malignancies, has only modestly improved over the last decades. Immunotherapy is one of the new treatment modalities explored for this disease. To investigate safety, tolerability, immunogenicity and obtain an impression of clinical activity of a p53 synthetic long peptide (p53‐SLP) vaccine, twenty patients with recurrent elevation of CA‐125 were included, eighteen of whom were immunized 4 times with 10 overlapping p53‐SLP in Montanide ISA51. The first 5 patients were extensively monitored for toxicity, but showed no ≥ grade 3 toxicity, thus accrual was continued. Overall, toxicity was limited to grade 1 and 2, mostly locoregional, inflammatory reactions. IFN‐γ producing p53‐specific T‐cell responses were induced in all patients who received all 4 immunizations as measured by IFN‐γ ELISPOT. An IFN‐γ secretion assay showed that vaccine‐induced p53‐specific T‐cells were CD4+, produced both Th1 and Th2 cytokines as analyzed by cytokine bead array. Notably, Th2 cytokines dominated the p53‐specific response. P53‐specific T‐cells were present in a biopsy of the last immunization site of at least 9/17 (53%) patients, reflecting the migratory capacity of p53‐specific T‐cells. As best clinical response, stable disease evaluated by CA‐125 levels and CT‐scans, was observed in 2/20 (10%) patients, but no relationship was found with vaccine‐induced immunity. This study shows that the p53‐SLP vaccine is safe, well tolerated and induces p53‐specific T‐cell responses in ovarian cancer patients. Upcoming trials will focus on improving T helper‐1 polarization and clinical efficacy. © 2009 UICC
HOXA methylation in normal endometrium from premenopausal women is associated with the presence of ovarian cancer: A proof of principle study
Authors: Widschwendter Martin , Apostolidou Sophia , Jones Allison A. , Fourkala Evangelia O. , Arora Rupali , Pearce Celeste Leigh , Frasco Melissa A. , Ayhan Ayse , Zikan Michal , Cibula David , Iyibozkurt Cem A. , Yavuz Ekrem , Hauser‐Kronberger Cornelia , Dubeau Louis , Menon Usha , Jacobs Ian J. 
Published: May 2009

AbstractDNA methylation of polycomb group target (PCGT) genes is an early step in carcinogenesis and could potentially be assayed to determine cancer risk prediction. To assess whether methylation changes in PCGT genes in normal tissue is able to predict the presence of cancer, we studied HOXA gene methylation in normal endometrium from premenopausal ovarian cancer patients and age‐matched healthy controls without ovarian cancer. DNA methylation of HOXA9 and HOXA11 genes in normal endometrium was associated with ovarian cancer in an initial test set and this was subsequently confirmed in independent validation sample sets. The overall risk of ovarian cancer was increased 12.3‐fold by high HOXA9 methylation for all stages, and 14.8‐fold for early stage ovarian cancers, independent of age, phase of the menstrual cycle and histology of the cancer. The results of this proof of principle study demonstrate the potential to detect ovarian cancer via analysis of normal endometrial cells and provide insight into the possible contribution of this novel approach in ovarian cancer risk prediction and prevention. © 2009 UICC
Hypoxia induces chemoresistance in ovarian cancer cells by activation of signal transducer and activator of transcription 3
Authors: Selvendiran Karuppaiyah , Bratasz Anna , Kuppusamy M. Lakshmi , Tazi Mia F. , Rivera Brian K. , Kuppusamy Periannan 
Published: May 2009

AbstractSignal transducer and activator of transcription 3 (STAT3) is activated in a variety of human cancers, including ovarian cancer. The molecular mechanism by which the STAT3 is activated in cancer cells is poorly understood. We observed that human ovarian xenograft tumors (A2780) in mice were severely hypoxic (pO2 ∼ 2 mmHg). We further observed that hypoxic exposure significantly increased the phosphorylation of STAT3 (pSTAT3) at the Tyr705 residue in A2780 cell line. The pSTAT3 (Tyr705) level was highly dependent on cellular oxygenation levels, with a significant increase at <2% O2, and without any change in the pSTAT3 (Ser727) or total STAT3 levels. The pSTAT3 (Tyr705) elevation following hypoxic exposure could be reversed within 12 hr after returning the cells to normoxia. The increased level of pSTAT3 was partly mediated by increased levels of reactive oxygen species generation in the hypoxic cancer cells. Conventional chemotherapeutic drugs cisplatin and taxol were far less effective in eliminating the hypoxic ovarian cancer cells suggesting a role for pSTAT3 in cellular resistance to chemotherapy. Inhibition of STAT3 by AG490 followed by treatment with cisplatin or taxol resulted in a significant increase in apoptosis suggesting that hypoxia‐induced STAT3 activation is responsible for chemoresistance. The results have important clinical implications for the treatment of hypoxic ovarian tumors using STAT3‐specific inhibitors. © 2009 UICC
Tumor ZAC1 expression is associated with the response to somatostatin analog therapy in patients with acromegaly
Authors: Theodoropoulou Marily , Tichomirowa Maria A. , Sievers Caroline , Yassouridis Alexander , Arzberger Thomas , Hougrand Olivier , Deprez Manuel , Daly Adrian F. , Petrossians Patrick , Pagotto Uberto , Beckers Albert , Stalla Günter K. 
Published: May 2009

AbstractSomatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and acromegaly‐associated growth hormone secreting pituitary tumors. Although a good portion of acromegalic patients gets normalized after SSA treatment, strict hormonal control is not achieved in a sizeable proportion of these patients. The reasons for this incomplete response to SSA treatment are unclear. We have found that the tumor suppressor ZAC1 (LOT1/PLAGL1) is essential for the antiproliferative effect of SSA in pituitary tumor cells. The aim of the present retrospective cohort study was to determine whether ZAC1 immunoreactivity in archival somatotrophinoma tissue derived from 45 patients with acromegaly routinely pretreated with SSA before surgery, was associated with response to SSA (normalization of GH, IGF‐I and presence of tumor shrinkage). All tumors displayed ZAC1 immunoreactivity [weak (+; n = 15), moderate (++; n = 16) and strong (+++; n = 14)]. A significant positive correlation was found between strong ZAC1 immunoreactivity and IGF‐I normalization and presence of tumor shrinkage after SSA treatment, which was not affected by age at diagnosis, gender or duration of SSA treatment. These in vivo data combined with the antiproliferative properties of ZAC1/Zac1 provide evidence of a mechanistic role for this transcription factor on SSA induced tumor shrinkage and hormone normalization. © 2009 UICC
TP53 Arg72Pro polymorphism and lung cancer risk: A meta‐analysis
Authors: Yan Lili , Zhang Deqiang , Chen Chengwen , Mao Yumin , Xie Yi , Li Yao , Huang Yan , Han Baohui 
Published: May 2009

AbstractNo clear consensus has been reached on the TP53 Arg72Pro polymorphism (G12139C) and lung cancer risk. Thus, a meta‐analysis was conducted to summarize the possible association. There was no statistical association between 12139C (Pro allele) and lung cancer risk in Caucasians compared with 12139G allele. However, the association was observed in all subjects (9,387 patients and 9,922 controls, p = 0.04, OR = 1.08, 95% CI 1.00–1.17), as well as in Asians (p = 0.0004, OR = 1.14, 95% CI 1.06–1.22). The association was also found in Asians under recessive genetic model (p < 0.00001, OR = 1.37, 95% CI 1.20–1.57) and homozygote comparison (CC vs. GG) (p < 0.0001, OR = 1.34, 95% CI 1.16–1.56). 12139C allele might increase the lung adenocarcinoma risk compared with 12139G allele (p = 0.01, OR = 1.11, 95% CI 1.02–1.21), and the effect was also found under recessive genetic model (p = 0.003, OR = 1.28, 95% CI 1.09–1.50) and homozygote comparison (CC vs. GG) (p = 0.007, OR = 1.28, 95% CI 1.07–1.52). There was an elevated association between the 12139C and the stage I lung cancer under dominant genetic model (p = 0.04, OR = 1.48, 95% CI 1.02–2.16), but no association was observed in other stages. No association of smoking was found between 12139C allele and lung cancer under recessive genetic model. Our result indicated that 12139C might increase the risk of lung cancer under recessive genetic model in adenocarcinoma, in Asians, and in lung cancer stage I. More studies stratified for lung cancer stage‐genotyping interaction should be performed to clarify the role of TP53 Arg72Pro polymorphism in the development of lung cancer. © 2009 UICC
Intrinsic resistance to the MEK1/2 inhibitor AZD6244 (ARRY‐142886) is associated with weak ERK1/2 signalling and/or strong PI3K signalling in colorectal cancer cell lines
Authors: Balmanno Kathryn , Chell Simon D. , Gillings Annette S. , Hayat Shaista , Cook Simon J. 
Published: May 2009

AbstractMutations in KRAS or BRAF frequently manifest in constitutive activation of the MEK1/2‐ERK1/2 signalling pathway. The MEK1/2‐selective inhibitor, AZD6244 (ARRY‐142886), blocks ERK1/2 activation and is currently undergoing clinical evaluation. Tumour cells can vary markedly in their response to MAPK or ERK kinase (MEK) inhibitors, and the presence of a BRAF mutation is thought to predict sensitivity, with the RAS mutations being associated with intrinsic resistance. We analysed cell proliferation in a panel of 19 colorectal cancer cell lines and found no simple correlation between BRAF or KRAS mutation and sensitivity to AZD6244, though cells that harbour neither mutation tended to be resistant. Cells that were sensitive arrested in G1 and/or underwent apoptosis and the presence of BRAF or KRAS mutation was not sufficient to predict either fate. Cell lines that were resistant to AZD6244 exhibited low or no ERK1/2 activation or exhibited coincident activation of ERK1/2 and protein kinase B (PKB), the latter indicative of activation of the PI3K pathway. In cell lines with coincident ERK1/2 and PKB activation, sensitivity to AZD6244 could be re‐imposed by any of the 3 distinct PI3K/mTOR inhibitors. We conclude that AZD6244 is effective in colorectal cancer cell lines with BRAF or KRAS mutations. Sensitivity to MEK1/2 inhibition correlates with a biochemical signature; those cells with high ERK1/2 activity (whether mutant for BRAF or KRAS) evolve a dependency upon that pathway and tend to be sensitive to AZD6244 but this can be offset by high PI3K‐dependent signalling. This may have implications for the use of MEK inhibitors in combination with PI3K inhibitors. © 2009 UICC
Three‐ and four‐dimensional visualization of cell migration using optical coherence tomography
Authors: Rey Sara M. , Považay Boris , Hofer Bernd , Unterhuber Angelika , Hermann Boris , Harwood Adrian , Drexler Wolfgang 
Published: May 2009

AbstractConventionally, cell chemotaxis is studied on two‐dimensional (2D) transparent surfaces, due to limitations in optical and image data‐collection techniques. However, surfaces that more closely mimic the natural environment of cells are often opaque. Optical coherence tomography (OCT) is a noninvasive label‐free imaging technique, which offers the potential to visualize moving cells on opaque surfaces and in three dimensions (3D). Here, we demonstrate that OCT is an effective means of time‐lapse videomicroscopy of Dictyostelium cells undergoing 3D (2D+time) cell migration on nitrocellulose substrates and 4D (3D+time) chemotaxis within low‐density agarose gels. The generated image sequences are compatible with current computer‐based image‐analysis software for quantification of cell motility. This demonstrates the utility of OCT for cell tracking and analysis of cell chemotaxis in complex environments. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transforming growth factor‐β3‐induced Smad signaling regulates actin reorganization during chondrogenesis of chick leg bud mesenchymal cells
Authors: Kim Dongkyun , Kim Jungsoo , Kang Shin‐Sung , Jin Eun‐Jung 
Published: May 2009

AbstractEndochondral ossification is characterized by a significant interdependence between cell shape and cytoskeletal organization that accompanies the onset of chondrogenic signaling. However, the mechanisms mediating these interactions have not been well studied. Here, treatment with transforming growth factor (TGF)‐β3 at a later stage of chondrogenesis led to activation of Smad‐2 signaling and the formation of intense stress fibers, which resulted in suppressing chondrogenic differentiation of leg bud mesenchymal cells. Moreover, specific siRNA knockdown of Smad‐2 reduced TGF‐β3‐induced stress fibers via physical interactions with β‐catenin. In conclusion, our results indicate that TGF‐β3‐induced Smad signaling, in conjunction with β‐catenin, is involved in the reorganization of the actin cytoskeleton into a cortical pattern with a concomitant rounding of cells. J. Cell. Biochem. © 2009 Wiley‐Liss, Inc.This article was published online on 28 May 2009. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 8 June 2009. J. Cell. Biochem. 107: 622–629, 2009. © 2009 Wiley‐Liss, Inc.