bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raft and cytoskeleton associations of an ABC transporter: P‐glycoprotein
Authors: Bacso Zsolt , Nagy Henrietta , Goda Katalin , Bene László , Fenyvesi Ferenc , Matkó János , Szabó Gábor 
Published: August 2004

AbstractBackgroundA novel flow cytometric assay has been described in an accompanying report (Gombos et al.,MethodsThe kinetics of the decrease in immunofluorescence intensity was analyzed after the addition of the raft‐preserving Triton X‐100 or Nonidet P‐40, both of which disrupt the entire membrane. Mild treatments by both detergents leave cells attached to only those proteins that are anchored to the cytoskeleton by rafts or independent of rafts. Agents that affect microfilaments and modulate membrane levels of cholesterol by cyclodextrin were used to distinguish between the raft‐mediated and non–raft‐related associations of the Pgp. Confocal microscopy and flow cytometric fluorescence energy transfer measurements were used to confirm colocalization of Pgp with raft constituents.ResultsThe assay was proved to be sensitive enough to resolve differences between the resistance of UIC2‐labeled cell‐surface Pgps to Triton X‐100 versus Nonidet P‐40. Approximately 34% of the UIC2 Fab‐labeled Pgp molecules were associated with the cytoskeleton through detergent‐resistant, cholesterol‐sensitive microdomains or directly, whereas approximately 15% were found to be directly linked to the cytoskeleton. Accordingly, confocal microscopy showed that Pgps colocalize with raft markers, mainly in microvilli. Fluorescence resonance energy transfer efficiency data indicating molecular proximity between Pgp and the raft markers CD44, CD59, and GM1‐gangliosides also suggested that a significant fraction of Pgps resides in raft microdomains. Raft association of Pgp appears to be of functional significance because its modulation markedly affected drug pumping.ConclusionsBy using the flow cytometric detergent resistance assay in kinetic mode, we were able to assess the extent of raft association and actin cytoskeleton anchorage of Pgp expressed at physiologically relevant levels. We demonstrated that a significant fraction of Pgp is raft associated on LS‐174‐T human colon carcinoma cells and that this localization may influence its transporter function. The kinetic flow cytometric detergent resistance assay presented in this report is considered to be generally applicable for the analysis of molecular interactions of membrane proteins expressed at low levels. © 2004 Wiley‐Liss, Inc.
Analysis of translocations that involve the NUP98 gene in patients with 11p15 chromosomal rearrangements
Authors: Kobzev Yuri N. , Martinez‐Climent Jose , Lee Sanggyu , Chen Jianjun , Rowley Janet D. 
Published: August 2004

AbstractThe NUP98 gene has been reported to be fused with at least 15 partner genes in leukemias with 11p15 translocations. We report the results of screening of cases with cytogenetically documented rearrangements of 11p15 and the subsequent identification of involvement of NUP98 and its partner genes. We identified 49 samples from 46 hematology patients with 11p15 (including a few with 11p14) abnormalities, and using fluorescence in situ hybridization (FISH), we found that NUP98 was disrupted in 7 cases. With the use of gene‐specific FISH probes, in 6 cases, we identified the partner genes, which were PRRX1 (PMX1; in 2 cases), HOXD13, RAP1GDS1, HOXC13, and TOP1. In the 3 cases for which RNA was available, RT‐PCR was performed, which confirmed the FISH results and identified the location of the breakpoints in patient cDNA. Our data confirm the previous findings that NUP98 is a recurrent target in various types of leukemia. © 2004 Wiley‐Liss, Inc.
Benzo[a]pyrene diol epoxide‐induced 9p21 aberrations associated with genetic predisposition to bladder cancer
Authors: Hazra Aditi , Grossman H. Barton , Zhu Yong , Luo Sherry , Spitz Margaret R. , Wu Xifeng 
Published: August 2004

AbstractCDKN2A, 9p21, encodes two alternatively spiked, functionally distinct, tumor‐suppressor proteins, P16INK4A and P14ARF, which play active roles in the RB1 and TP53 pathways, respectively. Deletion of 9p is one of the most frequent genomic alterations in bladder cancer. In addition, alterations of 9p21 and P16 are frequently seen in the epithelial cells of chronic smokers. This pilot study evaluated whether 9p21 aberrations induced by exposure in vitro to benzo[a]pyrene diol epoxide (BPDE), the metabolic product of benzo[a]pyrene, a constituent of tobacco smoke, were more common in the peripheral blood lymphocytes of 61 bladder cancer patients compared to 64 matched controls. Our hypothesis was that 9p21 sensitivity to BPDE reflects the susceptibility of a specific locus to damage from carcinogens in tobacco smoke. We found that BPDE‐induced chromosome band 9p21 aberrations were significantly higher in lymphocytes of bladder cancer cases (24.97 ± 5.26 per 1,000) than in controls (20.72 ± 4.51 per 1,000; P < 0.0001). However, no difference was observed for CEP9, a control locus. After adjustment for age, sex, ethnicity, and smoking status, 9p BPDE sensitivity had an odds ratio (OR) of 9.01 [95% confidence interval (95% CI) 3.75, 21.67] for bladder cancer. We further observed a gradient of elevated bladder cancer risk associated with increasing chromosomal damage. The adjusted ORs for subjects in the second, third, and highest quartiles of BPDE‐induced 9p21 aberrations relative to the first quartile were 0.48 (0.04, 5.69), 5.14 (1.12, 23.59), and 21.51 (4.75, 97.34), respectively, providing increasing dose–response evidence of the locus‐specific alterations. Thus, 9p21 may be a molecular target for BPDE‐induced damage in bladder cancer cases. © 2004 Wiley‐Liss, Inc.
Specific chromosome aberrations in peripheral blood lymphocytes are associated with risk of bladder cancer
Authors: Shao Lina , Lerner Seth L. , Bondaruk Jolanta , Czerniak Bogdan A. , Zeng Xiaomin , Grossman H. Barton , Spitz Margaret R. , Wu Xifeng 
Published: August 2004

AbstractSpecific chromosome aberrations in peripheral blood lymphocytes (PBLs) in chromosomes 9 and 11 may be associated with bladder cancer. To investigate this hypothesis, in this study, we used a whole‐chromosome painting technique to detect chromosomal aberrations in PBLs from 100 patients with bladder cancer and 100 matched controls. We also used a locus‐specific fluorescence in situ hybridization technique to study 9p21 and cyclin D1 gene (CCND1) aberrations in PBLs of 10 patients and 10 controls and in tumor tissues of 38 additional cases. The chromosome‐painting analysis showed that there were more aberrations of chromosomes 9 and 11 in bladder cancer patients than in controls. When categorized by type, the number of deletions of 9p and of translocations of chromosome 11 was significantly higher in patients than in controls (P < 0.05). Stratified analysis showed a larger odds ratio (OR) for bladder cancer in individuals with either a 9p deletion or a chromosome 11 translocation/amplification and an even larger OR in individuals with both aberrations. Using locus‐specific analysis, we found that 9p21 aberrations occurred more frequently in bladder cancer patients (12.1 per 1,000 interphase cells) than in controls (6.4 per 1,000 interphase cells, P < 0.05); CCND1 translocation and amplification were observed only in bladder cancer patients. Tumor tissue analysis showed that aberrations of 9p21 (40.0 per 100 interphase cells) and CCND1 (43.8 per 100 interphase cells) were very common. Thus, we concluded that 9p deletions and translocations of chromosome 11, especially at 9p21 and CCND1, are associated with bladder cancer. © 2004 Wiley‐Liss, Inc.
Stereoelectronic Effects in the Iodine‐Promoted Oxidation of Pentacyclic Tetrahydroisoquinolines
Authors: Koepler Oliver , Laschat Sabine , Miehlich Burkhard , Baro Angelika , Fischer Peter 
Published: August 2004

AbstractIodine‐promoted oxidations of the pentacyclic tetrahydroisoquinolines 4a, 4b, and 10 were investigated. Whereas the all‐cis diastereoisomer 4a containing an arylamino moiety gave the iminium ion 5 as the primary product, which subsequently underwent intramolecular aminal formation to 6, the corresponding all‐trans diastereoisomer 4b epimerized to the all‐cis diastereoisomer 4a via iminium ion 7. In contrast, tetrahydroisoquinoline 10 could be cleanly oxidized to the corresponding isoquinolizidinium ion 11. Mechanistic considerations were supported by molecular‐modeling calculations.
An Effective and Convenient Method for the Preparation of KAD‐1229
Authors: Liu Jianchao , Yang Yushe , Ji Ruyun 
Published: August 2004

AbstractA new convenient method for the asymmetric synthesis of the potent hypoglycemic agent KAD‐1229 was developed. The key step of this method is diasteroselective alkylation of 1 to give crude 2 (d.e.>93%) in good yield with the easily available Oppolzer's camphorsultam as chiral auxiliary. The overall yield of the product was 57%.
Synthesis, Spectroscopic Studies, and Crystal Structures of Phenylorganotin Derivatives with [Bis(2,6‐dimethylphenyl)amino]benzoic Acid: Novel Antituberculosis Agents
Authors: Dokorou Vaso , Kovala‐Demertzi Dimitra , Jasinski Jerry P. , Galani Angeliki , Demertzis Mavroudis A. 
Published: August 2004

AbstractThe novel triphenyl adduct of 2‐[(2,6‐dimethylphenyl)amino]benzoic acid (HDMPA; 1), i.e., [SnPh3(DMPA)] (2), the dimeric tetraorganostannoxane [Ph2(DMPA)SnOSn(DMPA)Ph2]2 (3), and the monomeric adduct [SnPh2(DMPA)2] (4), where DMPA is monodeprotonated HDMPA, have been prepared and structurally characterized by means of IR, 1H‐NMR, and 13C‐NMR spectroscopy. The structures of 1 and 2 have been determined by X‐ray crystallography. Single‐crystal X‐ray‐diffraction analysis of 1 revealed that there are two molecules in the asymmetric unit, HD1 and HD2, differing in conformation, both forming centrosymmetric dimers linked by H‐bonds between the carboxylic O‐atoms. X‐Ray analysis of 2 revealed a pentacoordinate structure containing Ph3Sn coordinated to the carboxylato group. Significant CH/π interactions and intramolecular H‐bonds stabilize the structures of 1 and 2, which self‐assembled via CH/π and π/π‐stacking interactions. The Ph3Sn adduct 2 was found to be a promising antimycobacterial lead compound, displaying activity against Mycobacterium tuberculosis H37Rv. The cytotoxiciy in the Vero cell line is also reported.
Two Novel ent‐Abietane Diterpenoids from Isodon xerophilus
Authors: Niu Xue‐Mei , Li Sheng‐Hong , Na Zhi , Lin Zhong‐Wen , Sun Han‐Dong 
Published: August 2004

AbstractThe tow novel ent‐abietane diterpenoids 1 and 2, named xerophilusins R and S, respectively (=(11β)‐6,11‐dihydroxy‐7,20‐dioxo‐ent‐abieta‐5,8(14),15(17)‐trien‐16‐oic acid δ‐lactone and (11β,15S)‐6,11,17‐trihydroxy‐7,20‐dioxo‐ent‐abieta‐5,8(14)‐dien‐16‐oic acid δ‐lactone, resp.), were isolated from Isodon xerophilus (C. J. Wu et H. W. LI) H. Hara. Their structures were established by spectroscopic means.
Lycopodine‐Type Lycopodium Alkaloids from Huperzia serrata
Authors: Tan Chang‐Heng , Zhu Da‐Yuan 
Published: August 2004

AbstractEleven Lycopodium alkaloids with a lycopodine‐type skeleton were isolated from the basic material of the whole plant of Huperzia serrata (Thunb.) Trev. (Huperziaceae). Among them, 12‐epilycodoline N‐oxide (=(12α,15R)‐12‐hydroxy‐15‐methyllycopodan‐5‐one N‐oxide; 1), 7‐hydroxylycopodine (=(15S)‐7‐hydroxy‐15‐methyllycopodan‐5‐one; 2), and 4,6α‐dihydroxylycopodine (=(6α,15R)‐4,6‐dihydroxy‐15‐methyllycopodan‐5‐one; 3) are new compounds. Their structures were identified spectroscopically, especially by means of 1D‐ and 2D‐NMR.
Thermal Isomerization of Isoborneols and Dehydroisoborneols to New Chiral Building Blocks in Terpenoid Synthesis
Authors: Rüedi Georg , Hansen Hans‐Jürgen 
Published: August 2004

AbstractThe substituted isoborneols 1a–1g and 5,6‐dehydroisoborneols 6a–6c, readily prepared in excellent yields from (+)‐camphor and (+)‐5,6‐dehydrocamphor (2) by aryl, vinyl, or alkyl Grignard addition in the presence of stoichiometric amounts of CeCl3, were thermally isomerized in a flow reactor system under DGPTI (dynamic gas‐phase thermo‐isomerization) conditions at temperatures between 480 and 630° to give the enantiomerically pure monocyclic carbonyl compounds 7a–7d, 19a, b, 23, and 24. In all cases, product formation proceeded highly regio‐ as well as stereoselectively. The absolute configurations of the new stereogenic centers were determined by 1H‐NOE measurements. DGPTI of the aryl substrates 1a–1d is proposed to effect initial cleavage of the weakest single bond in the molecule under formation of a diradical intermediate state followed by intramolecular H‐abstraction to afford the acetophenone derivatives 7a–7d. This reaction path was further supported by a 2H‐labeling study showing the OH group to be the exclusive H‐source. In contrast, DGPTI of the vinyl substrates 1e and 6b allowed concerted retro‐ene and oxy‐Cope rearrangements. In the case of 5,6‐dehydro‐2‐phenylisoborneol (6a), concomitant diradical and retro‐Diels–Alder reaction pathways could be observed. In addition, a new route to (+)‐trans‐α‐campholanic acid (9) and (+)‐trans‐α‐dihydrocampholytic acid (14) is presented by regioselective Baeyer–Villiger oxidation and subsequent hydrolysis of 7c and 7d, respectively.
Ozonolyse von Enolethern. 10. Mitteilung
Authors: Schank Kurt , Beck Horst , Pistorius Susanne 
Published: August 2004

AbstractOzonolysis of Enol Ethers. Part 10. Ozonization of Enol Ethers from 1,2‐ and 1,3‐Dicarbonyl Compounds: Direct Quantitative Synthesis of Phthalonic Acid Anhydride The results of ozonolyses of enol ethers from 1,2‐ and 1,3‐dicarbonyl compounds presented here strongly indicate that these reactions do not proceed via the established Criegee ozonolysis mechanism for nucleophilic CC bonds. The quantitative one‐step synthesis of phthalonic acid anhydride via ozonolysis of 2‐(methoxymethyliden)‐1H‐inden‐1,3(2H)‐dione (28a) is described. Furthermore, a revision of the theory of alkene ozonolysis in the presence of tetracyanoethylene (TCNE) is proposed on the basis of a single‐electron‐transfer (SET) chemistry.
Isolation and Structure Elucidation of Enniatins L, M1, M2, and N: Novel Hydroxy Analogs
Authors: Vongvilai Pornrapee , Isaka Masahiko , Kittakoop Prasat , Srikitikulchai Prasert , Kongsaeree Palangpon , Prabpai Samran , Thebtaranonth Yodhathai 
Published: August 2004

AbstractFour new cyclohexadepsipeptides, enniatins L (1), M1 (2), M2 (3), and N (4), have been isolated from an unidentified fungus (BCC 2629), together with the known enniatins B (5), H (6), and I (7), MK1688 (8), and enniatin B4 (9). Compounds 1–4 are the first enniatin analogs with an OH group at the side chain of one of the 2‐hydroxycarboxylic acid residues. The structures of 1–4 were elucidated by spectroscopic means and by X‐ray crystallography.
A New Preparation of 1,3,3‐Trimethylbicyclo[2.2.2]octan‐2,6‐dione, a Never Isolated Intermediate in a Total Synthesis of (+)‐Norpatchoulenol. Formal Total Synthesis of (±)‐Iso‐Norpatchoulenol
Authors: La Bella Angela , Leonelli Francesca , De Salve Ilse , Migneco Luisa M. , Marini Bettolo Rinaldo 
Published: August 2004

AbstractA new preparation and the isolation and spectroscopic characterization of 1,3,3‐trimethylbicyclo[2.2.2]octan‐2,6‐dione (3), a so far elusive key intermediate in the Liu–Ralitsch total synthesis of (+)‐norpatchoulenol ((+)‐1a), is described. The preparation of 3 constitutes also a formal total synthesis of (±)‐iso‐norpatchoulenol ((±)‐1b), since 3 is correlated to an intermediate in the Monti and co‐workers synthesis of (±)‐1b.
Acovulparine, a New Norditerpene Alkaloid from Aconitum vulparia
Authors: Csupor Dezső , Forgo Peter , Máthé Imre , Hohmann Judit 
Published: August 2004

AbstractAcovulparine (=1α,6β,7R,8β,14α,16β)‐4‐(hydroxymethyl)‐1,6,14,16‐tetramethoxyaconit‐19‐ene‐7,8‐diol; 1), a new norditerpene alkaloid, was isolated from the MeOH extract of the whole plants of Aconitum vulparia Reichenb., together with the known compounds lycoctonine (2) and delcosine (3). The structures were established by HR‐EI‐MS and advanced 2D‐NMR, including 1H‐NMR, JMOD, 1H,1H‐COSY, HSQC, and HMBC experiments. Acovulparine was found to contain the rare C(19)N azomethine group.
Confirmation of the Absolute (3R,3′S,6′R)‐Configuration of (all‐E)‐3′‐Epilutein
Authors: Molnár Péter , Deli József , Ősz Erzsébet , Zsila Ferenc , Simonyi Miklós , Tóth Gyula 
Published: August 2004

AbstractCircular dichroism (CD) spectroscopy was used to distinguish between the isomeric (all‐E)‐configured 3′‐epilutein (2) and 6′‐epilutein (8) to establish the absolute configuration of epilutein samples of different (natural and semisynthetic) origin, including samples of 2 obtained from thermally processed sorrel. Thus, the CD data of lutein (1) and epilutein samples (2) were compared. Our results unambiguously confirmed the (3R,3′S,6′R)‐configuration of all epilutein samples. Compound 2 was thoroughly characterized, and its 13C‐NMR data are published herewith for the first time.
(E/Z)‐Isomerization of 3′‐Epilutein
Authors: Molnár Péter , Deli József , Ősz Erzsébet , Matus Zoltán , Tóth Gyula , Zsila Ferenc 
Published: August 2004

Abstract3′‐Epilutein (=(all‐E,3R,3′S,6′R)‐4′,5′‐didehydro‐5′,6′‐dihydro‐β,β‐carotene‐3,3′‐diol; 1), isolated from the flowers of Caltha palustris, was submitted to both thermal isomerization and I2‐catalyzed photoisomerization. The structures of the main products (9Z)‐1, (9′Z)‐1, (13Z)‐1, (13′Z)‐1, (15Z)‐1, and (9Z,9′Z)‐1 were determined based on UV/VIS, CD, 1H‐NMR, and MS data.
Variation in the Settling Velocity of Suspended Particulate Matter in Shallow Lakes, with Special Implications for Mass Balance Modelling
Authors: Malmaeus Jan Mikael 
Published: August 2004

AbstractMeasurements of sedimentation were combined with water samples to calculate settling velocity of suspended particulate matter (SPM) in lakes. The study sites were open water stations and enclosures in Lake Erken (Sweden) and Lake Balaton (Hungary). Settling velocities were found to vary considerably both inside and outside the enclosures. Within sites, the differences between 25th and 75th percentiles of measured settling velocities of SPM were two‐ or three‐fold. Median settling velocities of SPM ranged from around 0.5 m/d in the enclosures of Lake Erken to more than 8 m/d in the open water of Lake Balaton. Special relevance was attributed to flocculation, which is known to be affected by, e.g., SPM concentration and turbulence. Even though not directly measured, the less turbulent environment inside the enclosures was suggested to explain the low settling velocity compared to the open water environment. Settling velocity apparently correlated with water current speed (r2 = 0.66; n = 12). Stepwise multiple linear regressions were used to relate the variability in settling velocity of SPM to the variability of possible controlling factors in a number of data subsets. In most cases, one variable describing the total amount of settling material (e.g., SPM) and one variable reflecting the composition of settling material (e.g., total phosphorus) were chosen. The use of suspended solids concentration to predict settling velocity in mass balance models was discussed. It was found that the mean slope between SPM and vSPM was close to 0.1 (m4d–1 g–1). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Epithelium and/or theca are required for ATP‐elicited K+ current in follicle‐enclosed Xenopus oocytes
Authors: Saldaña Carlos , Vázquez‐Cuevas Francisco , Garay Edith , Arellano Rogelio O. 
Published: August 2004

AbstractThe Xenopus follicular cell membrane is endowed with ATP‐sensitive K+ channels, which are operated by various transmitters. These generate the ionic response named IK,cAMP via a mechanism that involves intracellular cAMP synthesis. It is known that opening these K+ channels favors oocyte maturation. Follicle stimulation by adenosine (Ado) or ATP consistently generates a strong IK,cAMP via activation of P1 and P3 purinergic receptors; however, ATP can also inhibit IK,cAMP, apparently acting on a third receptor type. Here, we show that IK,cAMP might be elicited by ATP released within the follicle, and that current activation by ATP was entirely dependent on the presence of epithelial and/or theca layers. Morphological studies confirmed that removal of epithelium/theca in these follicles (e.t.r.) was complete, and activation of fast Cl− (Fin) currents by ATP in e.t.r. follicles confirmed that communication between oocyte and follicular cells remained unchanged. Thus, dependence on epithelium/theca was specific for ATP‐elicited K+ current. Using UTP and βγ‐MeATP as specific purinergic agents for IK,cAMP inhibition and activation, respectively, it was found that inhibition of IK,cAMP elicited by ATP or UTP was robustly present in e.t.r. follicles but was absent or strongly decreased in whole follicles (w.f.). Accordingly, this indicated that in w.f., epithelium and/or theca downregulated the IK,cAMP inhibition evoked by ATP, and that this control mechanism was absent in e.t.r. follicles. We suggest that this notable action on follicular cells involves one or both of two mechanisms, a paracrine transmitter released from epithelial and/or theca layers and action of ecto‐ATPases. © 2004 Wiley‐Liss, Inc.
Differential expression of claudin‐2 along the human intestine: Implication of GATA‐4 in the maintenance of claudin‐2 in differentiating cells
Authors: Escaffit F. , Boudreau F. , Beaulieu J.‐F. 
Published: August 2004

AbstractClaudins, and particularly claudin‐2, are important regulatory components of tight junction permeability. A better understanding of the involvement of claudin‐2 in intestinal barrier functions requires the characterization of its distribution and regulation in the intestine. Interestingly, the claudin‐2 gene promoter harbors a number of similarities to that of sucrase‐isomaltase, a marker of enterocyte differentiation. We thus investigated the expression of claudin‐2 in relation to the transcription factors CDX2, HNF‐1α, and GATA‐4 in the human intestine. The characterization of claudin‐2 and the expression of the above transcription factors were performed by immunofluorescence, Western blot, and RT‐PCR in the developing human intestinal epithelium. The functional role of CDX2, HNF‐1α, and GATA‐4 on claudin‐2 regulation was also examined by ectopic expression studies in intestinal cell models. Claudin‐2 was detected in both crypt and villus cells of the small intestine but restricted to undifferentiated crypt cells in the colon. CDX2 and HNF‐1α were expressed along the entire intestine whereas GATA‐4 was undetectable in the colon. Accordingly, in the colonic Caco‐2 cell model, claudin‐2 was found to be present only in undifferentiated cells. Like in the colonic epithelium, GATA‐4 was found to be also lacking in Caco‐2 cells while CDX2 and HNF‐1α were present at significant levels. Cotransfection experiments showed that the claudin‐2 promoter was activated by CDX2, HNF‐1α, and GATA‐4 in a cooperative manner. Furthermore, forced GATA‐4 expression in Caco‐2 cells enhances maintenance of claudin‐2 expression during differentiation. These observations suggest that optimal claudin‐2 expression in the gut relies on the presence of GATA‐4, suggesting a role for this factor in intestinal regionalization. © 2004 Wiley‐Liss, Inc.