bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Stephaoxocane Alkaloids from Stephania longa
Authors: Zhang Hua , Yue Jian‐Min 
Published: June 2006

AbstractThree new stephaoxocane‐type alkaloids, stephalonganines A–C (1–3), together with the known eletefine (4), were isolated from the whole plant of Stephania longa. Their structures were fully characterized spectroscopically, and the absolute configurations of the new alkaloids were assigned by comparison of their circular‐dichroism (CD) data with those of 1,2‐dihydrostephaoxocanine (5), in combination with 2D‐NMR experiments.
Syntheses and Crystal Structures of Ammoniates with the Phenyl‐Substituted Polytin Anions Sn2Ph$\rm{_{\bf 4}^{{\bf 2} - } }$, cyclo‐Sn4Ph$\rm{_{\bf 4}^{{\bf 4} - } }$, and Sn6Ph$\rm{_{{\bf 12}}^{{\bf 2} - } }$
Authors: Wiesler Katharina , Suchentrunk Christof , Korber Nikolaus 
Published: June 2006

AbstractThe reaction of diphenyltin dichloride with the binary Zintl phase K4Sn9 in the presence of excess lithium and 18‐crown‐6 in liquid ammonia led to the ammoniate [K(18‐crown‐6)(NH3)2]2Sn2Ph4 (1). The analogous reaction with K4Ge9 and potassium in the absence of further alkali metal ligands resulted in the compound [K2(NH3)12]Sn6Ph12 ⋅ 4 NH3 (3). Cs6[Sn4Ph4](NH2)2 ⋅ 8 NH3 (2) was prepared by reacting diphenyltin dichloride with a surplus of caesium in liquid ammonia. The low‐temperature single‐crystal structure determinations show all compounds to contain phenyl‐substituted polyanions of tin. Compound 1 is built from Sn2Ph$\rm{_4^{2 - } }$ anions consisting of Sn dumbbells with two Ph substituents at each Sn‐atom. Compound 2 contains cyclo‐Sn4Ph$\rm{_4^{4 - } }$ anions formed by a four‐membered tin ring in butterfly conformation with one Ph substituent at each Sn‐atom in an (all‐trans)‐configuration. Sn6Ph$\rm{_{12}^{2 - } }$ in 3 is a zig‐zag Sn6 chain with two substituents at each of the Sn‐atoms. Both 1 and 3 have molecular counter cations, in the latter case the unprecedented dinuclear potassiumammine complex [K2(NH3)12]2+ is observed. Compound 2 shows a complicated three‐dimensional network of CsSn interactions.
One‐Pot Three‐Component Synthesis of Highly Functionalized 2,3‐Dihydro‐1,3‐dioxo‐1H,5H‐pyrazolo[1,2‐a][1,2,4]triazoles
Authors: Adib Mehdi , Sayahi Mohammad Hosein , Mahmoodi Niusha , Bijanzadeh Hamid Reza 
Published: June 2006

AbstractThe reactive 1 : 1 zwitterionic intermediate formed by the addition of isocyanides to dialkyl acetylenedicarboxylates was trapped with 4‐arylurazoles to produce the highly functionalized pyrazolo[1,2‐a][1,2,4]triazoles 5 in good yields (Table). The structures of the products 5a–h were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR), by EI‐MS, and elemental analysis. A possible mechanism for this reaction is proposed (Scheme).
Synthetic dsDNA‐Binding Peptides Using Natural Compounds as Model
Authors: Borgions Filip , Ghyssels Daniel , Van Aerschot A. , Rozenski J. , Herdewijn Piet 
Published: June 2006

AbstractWe have developed a series of short DNA‐binding peptides containing newly synthesized, unnatural as well as natural amino acid building blocks. By a combinatorial‐library approach, oligopeptides were developed with moderate dsDNA‐binding affinities. Two strategies were used to further enhance the binding affinity of the lead peptides: Ac‐Arg‐Ual‐Sar‐Chi‐Chi‐Chi‐Arg‐NH2and Ac‐Arg‐Cbg‐Cha‐Chi‐Chi‐Tal‐Arg‐NH2. Site‐selective amino acid substitutions increased the binding affinities up to 2 × 10−5 M. Further enhancement of the binding affinities could be achieved by coupling of an acridine intercalating unit, using linker arms of different length and flexibility. With the introduction of a new lysine‐based acridine unit, different types of oligopeptide–acridine conjugates were designed using known dsDNA‐binding ligands as model compounds. The binding capacities of these new oligopeptide–acridine conjugates have been investigated by a fluorescent intercalator (ethidium bromide) displacement (FID) assay. With the synthesis of the dipeptide–acridine conjugates, binding affinities in the low micromolar range were obtained (6.4 × 10−6 M), which is similar to the binding strength of the well‐known DNA binderHoechst 33258.
New Phenolic Constituents from the Stems of Spatholobus suberectus
Authors: Zhang Shuwei , Xuan Lijiang 
Published: June 2006

AbstractThree new phenolic compounds, 5‐O‐(β‐apiosyl‐(1 → 2)‐O‐β‐xylopyranosyl)gentisic acid (1), 1‐O‐(β‐apiosyl‐(1 → 6)‐O‐β‐glucopyranosyl)‐3‐O‐methylphloroglucinol (2), and 15‐O‐(α‐rhamnopyranosyl)aloe‐emodin (3), together with the known compound aloe emodin (4), were isolated from the stems of Spatholobus suberectus. Their structures were characterized by chemical and spectroscopic methods. The absolute configurations of the sugar units were not determined.
Regio‐ and Stereocontrolled Synthesis of (2R*,3R*,4R*)‐3,4‐Dichloro‐1,2,3,4,5,8‐hexahydronaphthalen‐2‐yl Acetate via Tandem SN2′ Reactions
Authors: Horasan‐Kishali Nurhan , Sahin Ertan , Kara Yunus 
Published: June 2006

AbstractThe hydroperoxy endoperoxide 3, obtained by photooxygenation of isotetralin (= 1,4,5,8‐tetrahydronaphthalene; 1), was reduced with thiourea, and the resulting intermediate 4 was converted, after acetylation with acetyl chloride, to the interesting, double‐chlorinated acetate 5 in an unprecedented tandem reaction (Scheme 1). The structures and relative configurations of 3 and 5 were determined by NMR spectroscopy and by single‐crystal X‐ray‐diffraction analyses (Figs. 1 and 2, resp.). A mechanistic rationalization for the conversion of 4 to 5 is proposed (Scheme 2).
Novel Synthesis of Mafenide and Other Amino Sulfonamides by Electrochemical Reduction of Cyano Sulfonamides
Authors: Lateef Shaik , Mohan Srinivasulu Reddy Krishna , Rameshraju Rudraraju , Reddy Srinivasulu Reddy Jayarama 
Published: June 2006

AbstractBoth aliphatic and aromatic amino sulfonamides such as mafenide (1a) were synthesized in good yields (80–86%) by direct electrochemical hydrogenation of the corresponding nitriles in an undivided cell containing a Ni cathode, a Pt anode, and Raney Ni as catalyst (Table 1). The reaction can be performed without external supply of pressurized gas by in situ generation of H2. Slightly elevated temperatures (45°) and low current densities (10 mA/cm2) are favorable conditions for this type of electrochemical nitrile hydrogenation. Our synthetic protocol does not require high‐pressure equipment or chemical hazards, is environmentally very friendly, and more economical than traditional methods. The concentration of adsorbed H. radicals on the catalyst surface can be easily controlled by adjusting the electric potential, which may lead to improved product selectivity and, at the same time, reduces the risk of explosion and fire.
Transcriptional profiling endometrial carcinomas microdissected from DES‐treated mice identifies changes in gene expression associated with estrogenic tumor promotion
Authors: Kabbarah Omar , Mallon Mary Ann , Pfeifer John D. , Goodfellow Paul J. 
Published: June 2006

AbstractExposure to unopposed estrogen is a potent risk factor for developing human endometrial cancer. However, little is known about the transcriptional changes elicited by estrogens in endometrial carcinogenesis, in part, because of genetic and environmental heterogeneity of human tumors. We have begun to chart the expression signatures of endometrial tumors promoted with the synthetic estrogen, diethylstilbestrol (DES), in inbred mice. As expected, laser‐capture‐microdissected endometrial cancers from DES‐treated mice displayed a large number of transcriptional changes when compared to uninvolved endometrial epithelium. Genes differentially expressed in carcinomas included cell adhesion and extracellular matrix genes (Decorin as 1 example), developmental genes (Hoxa11), and cytokine signaling genes (Socs3). The DES‐promoted carcinomas appeared to fall into 2 distinct transcriptional classes, and expression of the tumor suppressor Pten was among the top discriminators between the 2 cancer groups. Pten was down regulated in the majority of the DES‐promoted carcinomas, which is analogous to the frequent loss of PTEN expression in human endometrial tumors. Although preliminary, these observations suggest that the cancers that arise in the DES model bear similarities to human endometrial cancers and provide insights into transcriptional alterations that accompany estrogen‐driven endometrial carcinogenesis. © 2006 Wiley‐Liss, Inc.
Prognostic significance of matrix metalloproteinase‐7 in epithelial ovarian cancer and its relation to β‐catenin expression
Authors: Sillanpää Sari M. , Anttila Maarit A. , Voutilainen Kirsi A. , Ropponen Kirsi M. , Sironen Reijo K. , Saarikoski Serpo V. , Kosma Veli‐Matti 
Published: June 2006

AbstractWe investigated the expression and prognostic significance of matrix metalloproteinase (MMP) ‐7, its relation to β‐catenin expression and clinicopathological factors in epithelial ovarian cancer. The expression of MMP‐7 was analyzed immunohistochemically in a series of 284 primary epithelial ovarian cancers, their 36 metastases and 8 normal ovaries. In cancers with endometrioid histology, a high percentage area of MMP‐7 expression and an intense MMP‐7 signal was significantly associated with nuclear positivity of β‐catenin in cancer cells (p = 0.003, χ2 = 8.853 and p = 0.030, χ2 = 4.713, respectively). In all tumors and nonendometrioid subgroup, a low percentage area of MMP‐7 positive tumor cells was significantly correlated with a high histological grade of the tumor (p = 0.003 and 0.005, respectively), in all tumors also with advanced stage of the tumor (p = 0.002) and large primary residual tumor (p = 0.005). A 10‐year disease‐related survival (DRS) was significantly better when the percentage area of MMP‐7 expression in cancer cells was high, when compared to low (p = 0.0008). A high percentage area of intense MMP‐7 signal in cancer cells predicted a significantly more favorable DRS and recurrence‐free survival (RFS) (p = 0.0003 and 0.0052, respectively). In multivariate analysis, a high percentage area of intense MMP‐7 signal in tumor cells was an independent prognostic factor, predicting favorable DRS and RFS. The present study showed that intense MMP‐7 signal in tumor cells is an independent prognostic factor predicting better survival in epithelial ovarian cancer. © 2006 Wiley‐Liss, Inc.
M‐CAM expression as marker of poor prognosis in epithelial ovarian cancer
Authors: Aldovini Daniela , Demichelis Francesca , Doglioni Claudio , Di Vizio Dolores , Galligioni Enzo , Brugnara Sonia , Zeni Bruna , Griso Claudia , Pegoraro Cristina , Zannoni Marina , Gariboldi Manuela , Balladore Emanuela , Mezzanzanica Delia , Canevari Silvana , Barbareschi Mattia 
Published: June 2006

AbstractCurrently available clinico–pathologic criteria provide an imperfect assessment of outcome for patients with advanced epithelial ovarian cancer (EOC). Identification of prognostic factors related to tumor biology might improve this assessment. We investigated the prognostic significance of the melanoma cell adhesion molecule (M‐CAM) in EOC. Using the same antibody, M‐CAM expression was tested by Western blotting in protein extracts and by immunohistochemestry in tissue microarrays generated from 133 consecutively resected, well characterized EOC samples. Fisher test, Kaplan–Meier method and Cox proportional hazards analysis were used to relate M‐CAM expression to clinico–pathological variables and to time to progression (TTP) and overall survival (OS). In vitro biochemical analysis showed a progressively increased M‐CAM expression from normal to malignant cells. M‐CAM protein, detected immunohistochemically, was significantly associated with advanced tumor stage, serous and undifferentiated histotype, extent of residual disease and p53 accumulation. Presence or absence of M‐CAM significantly divided patients according to their TTP (median, 22 vs. 79 months, respectively; log‐rank p = 0.001) and OS (median, 42 vs. 131 months, respectively; log‐rank p = 0.0003). In the subgroup of advanced stage patients who achieved complete response after front‐line treatment, M‐CAM expression and absence of residual disease were significantly associated with shorter TTP (p = 0.003, HR 5.25, 95% Cl 1.79–15.41 and p = 0.011, HR 3.77, 95% Cl 1.36–10.49 respectively) at the multivariate level. In the same sub‐group of patients, M‐CAM expression remained the only parameter significantly associated with OS (p = 0.005, HR 3.35, 95% Cl 1.42–6.88). M‐CAM is a marker of early relapse and poorer outcome in EOC. In particular, M‐CAM expression identifies a subgroup of front‐line therapy‐responding patients who undergo dramatic relapses, thus helping to better select patients who might benefit from new/alternative therapeutic modalities. © 2006 Wiley‐Liss, Inc.
The expression levels of the transcriptional regulators p300 and CtBP modulate the correlations between SNAIL, ZEB1, E‐cadherin and vitamin D receptor in human colon carcinomas
Authors: Peña Cristina , García José Miguel , García Vanesa , Silva Javier , Domínguez Gemma , Rodríguez Rufo , Maximiano Constanza , García de Herreros Antonio , Muñoz Alberto , Bonilla Félix 
Published: June 2006

AbstractZEB1 and SNAIL repress CDH1 and induce epithelial–mesenchymal transition (EMT). However, SNAIL and ZEB1 also activate or regulate other target genes in different ways. For instance, vitamin D receptor (VDR), which activates CDH1 expression upon ligand binding, is repressed by SNAIL but induced by ZEB1. We examined whether the biological activity of SNAIL and ZEB1 in colon cancer is regulated by interacting cofactors. The mRNA expression levels of SNAIL and ZEB1, and of transcriptional regulators p300 and CtBP, were measured by RT‐PCR in tumor and normal tissue from 101 colon carcinoma patients. Overexpression of SNAIL was associated with down‐regulation of CDH1 and VDR (p = 0.004 and p < 0.001). CDH1 correlated with VDR (r = 0.49; p < 0.001). ZEB1 expression also correlated with VDR (r = 0.23; p = 0.019). However, when CtBP was strongly expressed, ZEB1 was inversely correlated with CDH1 (r = −0.39; p = 0.053). Furthermore, when there were elevated p300 expression levels, the correlation between expression of ZEB1 and VDR was stronger (r = 0.38; p = 0.070). Association between SNAIL expression and down‐regulation of CDH1 and VDR was lost in tumors in which p300 and CtBP were strongly expressed. These results indicate that the levels of expression of CtBP and p300 are critical for the action of SNAIL and ZEB1, which have a pivotal role in EMT, and show the importance of CtBP and p300 for tumor progression. © 2006 Wiley‐Liss, Inc.
Cancer‐specific targeting of an adenovirus‐delivered herpes simplex virus thymidine kinase suicide gene using translational control
Authors: Mathis J. Michael , Williams B. Jill , Sibley Don A. , Carroll Jennifer L. , Li Jie , Odaka Yoshinobu , Barlow Shayne , Nathan Cherie‐Ann O. , Li Benjamin D. L. , DeBenedetti Arrigo 
Published: June 2006

AbstractTwo technical hurdles, gene delivery and target specificity, have hindered the development of effective cancer gene therapies. In order to circumvent the problem of tumor specificity, the suicide gene, HSV‐1 thymidine kinase (HSV‐Tk), was modified with a complex 5′ upstream‐untranslated region (5′‐UTR) that limits efficient translation to cells expressing high levels of the translation initiation factor, eIF4E. Since previous studies have shown that most tumor cells express elevated levels of eIF4E, tumor‐specific gene delivery was optimized by incorporation of the 5′‐UTR‐modified suicide gene (HSV‐UTk) into an adenovirus vector (Ad‐CMV‐UTk). The efficacy of this novel approach of targeting suicide gene expression and limiting cytotoxicity by means of translational restriction was tested in vitro with the use of the human breast cancer cell lines (MCF‐7, MDA‐MB435, and ZR‐75‐1). As controls, normal MCF10A, HMEC, and HMSC cell lines that express relatively low levels of eIF4E were used. Real‐time reverse‐transcription polymerase chain reaction (RT‐PCR) was used to quantify HSV‐Tk mRNA for cells infected with Ad‐CMV‐UTk as well as with Ad‐CMV‐Tk (a control adenovirus in which HSV‐Tk is not regulated at the level of translation). Translation of HSV‐Tk in the Ad‐infected cells was measured by Western blot analysis. In addition, cytotoxicity was determined following treatment with the pro‐drug ganciclovir (GCV) using an MTT viability assay. Finally, microPET imaging was used to assess cancer cell‐specific expression of HSV‐Tk and expression in normal tissues in vivo after intraperitoneal injection of Ad‐CMV‐Tk or Ad‐CMV‐UTk. These data collectively showed enhanced cancer cell‐specific gene expression and reduced normal tissue gene expression for the Ad‐HSV‐UTk compared to the Ad‐CMV‐Tk, leading to increased cancer cell‐enhanced GCV cytotoxicity. These results indicate that translational targeting of suicide gene expression in tumor cells in vitro and in vivo is effective and may provide a platform for enhanced cancer gene therapy specificity. Copyright © 2006 John Wiley & Sons, Ltd.
Magnetic acoustic resonance immunoassay (MARIA): a multifrequency acoustic approach for the non‐labelled detection of biomolecular interactions
Authors: Araya‐Kleinsteuber Bernardita , Roque Ana C. A. , Kioupritzi Eleftheria , Stevenson Adrian C. , Lowe Christopher R. 
Published: June 2006

AbstractA unique sensing platform, comprising an electromagnetic field detector and an acoustic resonator, has been used as a wireless system for remote sensing of biorecognition events. The MARS (Magnetic Acoustic Resonator Sensor) technique has proven useful for detecting the formation of protein multilayers derived from specific binding phenomena. The technique enables multifrequency analysis, without the need of electrodes attached to the sensing element, and also facilitates the in situ surface modification of the substrate for antibody attachment. The MARS sensor was utilized as the platform on which a standard immunoassay was carried out. Two different conditions for the attachment of the first antibody to the quartz surface were tested: (i) Adsorption of the antibody onto the surface of a bare quartz disc; (ii) covalent immobilization of the antibody to a chemically modified quartz surface. Both methods can be successfully utilized for the ‘label‐less’ detection of the biorecognition event between goat IgG and anti‐goat IgG by analysis of the multifrequency spectrum. Covalent attachment of the primary antibody results in a more efficient immobilization, with higher surface density, and a consistently enhanced response for the binding of the secondary antibody. This approach will be of interest to life scientists and biochemists that require high performance assay methodologies that do not use chemical labels. Copyright © 2006 John Wiley & Sons, Ltd.
Diagnosis of breast cancer using diffuse reflectance spectroscopy: Comparison of a Monte Carlo versus partial least squares analysis based feature extraction technique
Authors: Zhu Changfang , Palmer Gregory M. , Breslin Tara M. , Harter Josephine , Ramanujam Nirmala 
Published: June 2006

AbstractBackground and ObjectiveWe explored the use of diffuse reflectance spectroscopy in the ultraviolet‐visible (UV‐VIS) spectrum for the diagnosis of breast cancer. A physical model (Monte Carlo inverse model) and an empirical model (partial least squares analysis) based approach, were compared for extracting diagnostic features from the diffuse reflectance spectra.Study Design/MethodsThe physical model and the empirical model were employed to extract features from diffuse reflectance spectra measured from freshly excised breast tissues. A subset of extracted features obtained using each method showed statistically significant differences between malignant and non‐malignant breast tissues. These features were separately input to a support vector machine (SVM) algorithm to classify each tissue sample as malignant or non‐malignant.Results and ConclusionsThe features extracted from the Monte Carlo based analysis were hemoglobin saturation, total hemoglobin concentration, beta‐carotene concentration and the mean (wavelength averaged) reduced scattering coefficient. Beta‐carotene concentration was positively correlated and the mean reduced scattering coefficient was negatively correlated with percent adipose tissue content in normal breast tissues. In addition, there was a statistically significant decrease in the beta‐carotene concentration and hemoglobin saturation, and a statistically significant increase in the mean reduced scattering coefficient in malignant tissues compared to non‐malignant tissues. The features extracted from the partial least squares analysis were a set of principal components. A subset of principal components showed that the diffuse reflectance spectra of malignant breast tissues displayed an increased intensity over wavelength range of 440–510 nm and a decreased intensity over wavelength range of 510–600 nm, relative to that of non‐malignant breast tissues. The diagnostic performance of the classification algorithms based on both feature extraction techniques yielded similar sensitivities and specificities of approximately 80% for discriminating between malignant and non‐malignant breast tissues. While both methods yielded similar classification accuracies, the model based approach provided insight into the physiological and structural features that discriminate between malignant and non‐malignant breast tissues. Lasers Surg. Med. © 2006 Wiley‐Liss, Inc.
Effects of low‐level laser therapy (LLLT) on the nuclear factor (NF)‐κB signaling pathway in traumatized muscle
Authors: Rizzi Carem Fetter , Mauriz José Luis , Freitas Corrêa Daniela Sousa , Moreira Andréa Janz , Zettler Claudio Galeano , Filippin Lidiane Isabel , Marroni Norma Possa , González‐Gallego Javier 
Published: June 2006

AbstractBackground and ObjectiveTo investigate the effects of low‐level laser therapy (LLLT) on nuclear factor kappa B (NF‐κB) activation and inducible nitric oxide synthase (iNOS) expression in an experimental model of muscle trauma.Study Design/Materials and MethodsInjury to the gastrocnemius muscle in the rat was produced by a single impact blunt trauma. A low‐level galium arsenide (Ga–As) laser (904 nm, 45 mW, and 5 J/cm2) was applied for 35 seconds duration, continuously.ResultsHistological abnormalities with increase in collagen concentration, and oxidative stress were observed after trauma. This was accompanied by activation of NF‐κB and upregulation of iNOS expression, whereas protein concentration of IκBα decreased. These effects were blocked by LLLT.ConclusionLLLT reduced the inflammatory response induced by trauma and was able to block the effects of reactive oxygen species (ROS) release and the activation of NF‐κB. The associated reduction of iNOS overexpression and collagen production suggest that the NF‐κB pathway may be a signaling route involved in the pathogenesis of muscle trauma. Lasers Surg. Med. © 2006 Wiley‐Liss, Inc.