bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microbial Transformation of Sesquiterpenes, (−)‐Ambrox® and (+)‐Sclareolide
Authors: Choudhary M. Iqbal , Musharraf Syed Ghulam , Sami Amtul , Atta‐ur‐Rahman  
Published: October 2004

AbstractThe microbial transformation of (−)‐Ambrox® (1), a perfumery sesquiterpene, by a number of fungi, by means of standard two‐stage‐fermentation technique, afforded ambrox‐1α‐ol (2), ambrox‐1α,11α‐diol (3), ambrox‐1α,6α‐diol (4), ambrox‐1α,6α,11α‐triol (5), ambrox‐3‐one (6), ambrox‐3β‐ol (7), ambrox‐3β,6β‐diol (8), 13,14,15,16‐tetranorlabdane‐3,8,12‐triol (9), and sclareolide (10) (Schemes 1 and 2). Further incubation of compound 10 with Cunninghamella elegans afforded 3‐oxosclareolide (11), 3β‐hydroxysclareolide (12), 2α‐hydroxysclareolide (13), 2α,3β‐dihydroxysclareolide (14), 1α,3β‐dihydroxysclareolide (15), and 3β‐hydroxy‐8‐episclareolide (16) (Scheme 3). Metabolites 2–5, 12, 13, and 16 were found to be new compounds. The major transformations include a reaction path involving hydroxylation, ether‐bond cleavage and inversion of configuration. Metabolites 11–16 of sclareolide showed significant phytotoxicity (Table 1). The structures of the metabolites were characterized on the basis of spectroscopic techniques.
Holo‐ and Hemidirected Coordination Spheres in a Novel Three‐Dimensional Polymeric KIPbII Heteropolynuclear Complex: X‐Ray Crystal Structure of [KPb(AcO)2(SCN)]n
Authors: Morsali Ali , Mahjoub Ali Reza 
Published: October 2004

AbstractA novel three‐dimensional polymeric KIPbII heteropolynuclear complex, [KPb(AcO)2(SCN)]n, with mixed acetate and thiocyanate ligands, has been synthesized and characterized. Its single‐crystal X‐ray structure (Fig. 1) shows three types of K+ ions with coordination numbers of seven, and three types of Pb2+ ions with coordination numbers of eight, eight, and nine, respectively. The Pb centers (Pb(1) and Pb(3); Fig. 1) with coordination numbers of nine and eight, respectively, possess stereochemically ‘inactive’ electron lone pairs, and the coordination sphere is holodirected. However, the arrangement of O‐, N‐, and S‐atoms for the eight‐coordinated Pb(2) suggests a gap or hole in the coordination geometry around this atom. This ‘hole’ is possibly occupied by a stereochemically ‘active’ electron lone pair of Pb(2), and its coordination sphere is, thus, hemidirected.
Modelling two‐dimensional steady‐state groundwater flow and flow sensitivity to boundary conditions in blanket peat complexes
Authors: Lapen D. R. , Price J. S. , Gilbert R. 
Published: October 2004

AbstractThis study used a two‐dimensional steady‐state finite‐element groundwater flow model to simulate groundwater flow in two Newfoundland blanket peat complexes and to examine flow system sensitivity to changes in water table recharge and aquifer properties. The modelling results were examined within the context of peat‐forming processes in the two complexes. Modelled flow compared favourably with observed flow. The sensitivity analyses suggested that more highly decomposed bog peat along bog margins probably has/had a positive impact on net peat accumulation within bog interiors. Peat with lower hydraulic conductivity along bog margins effectively impedes lateral drainage, localizes water table drawdown to extreme bog margins, and elevates water tables along bog interiors. Peat formation and elevated water tables in adjacent poor fens/laggs currently rely on placic and ortstein horizons impeding vertical drainage and water flow inputs from adjacent bogs. Modest reductions in atmospheric recharge were found to govern bog‐flow‐system geometries in a way that would adversely affect paludification processes in adjacent fens/laggs. Copyright © 2004 John Wiley & Sons, Ltd.
Dosing and scheduling influence the antitumor efficacy of a phosphinic peptide inhibitor of matrix metalloproteinases
Authors: Dive Vincent , Andarawewa Kumari L. , Boulay Anne , Matziari Magdalini , Beau Fabrice , Guerin Eric , Rousseau Bernard , Yiotakis Athanasios , Rio Marie‐Christine 
Published: October 2004

AbstractThe in vivo disposition and antitumor efficacy of a newly developed phosphinic matrix metalloproteinase inhibitor (RXP03) were examined. RXP03 potently inhibits MMP‐11, MMP‐8 and MMP‐13, but not MMP‐1 and MMP‐7. Twenty‐four hours after i.p. injection into mice, most of the RXP03 was recovered intact in plasma, feces (biliary excretion) and tumor tissue. Pharmacokinetic parameters indicated that, after an i.p. dose of 100 μg/day, the plasma concentration of RXP03 over 24 hr remained higher than the Ki values determined for MMP‐11, MMP‐8 and MMP‐13. Efficacy of RXP03 on the growth of primary tumors induced by s.c. injection of C26 colon carcinoma cells in mice was observed to depend both on RXP03 doses and treatment schedules. Tumor volumes in mice treated for 18 days with 50, 100 and 150 μg/day of RXP03 were decreased compared with control tumor volumes, 100 μg/day being the most effective dose. Treatment at higher dose (600 μg/day) did not significantly reduce the tumor size as compared to control. Short treatments with RXP03 100 μg/day, 3 to 7 days after C26 inoculation, were more effective on tumor growth than continuous treatment over 18 days. Strikingly, RXP03 treatment started 6 days after the C26 injection and continued until day 18 led to stimulation of tumor growth, as compared to control. These paradoxical effects, depending on the RXP03 treatment schedule, underline the need to define carefully the spatiotemporal function of each MMP at various stages of tumor growth to achieve optimal therapeutic effects by MMP inhibitor treatment.
Folate intake and colorectal cancer risk: A meta‐analytical approach
Authors: Sanjoaquin Miguel A. , Allen Naomi , Couto Elisabeth , Roddam Andrew W. , Key Timothy J. 
Published: October 2004

AbstractAdequate consumption of folate may reduce the risk of colorectal cancer. We performed a meta‐analysis of 7 cohort and 9 case‐control studies that examined the association between folate consumption and colorectal cancer risk. In cohort studies, the association between folate consumption and colorectal cancer risk was stronger for dietary folate (folate from foods alone; relative risk for high vs. low intake = 0.75; 95% CI = 0.64–0.89) than for total folate (folate from foods and supplements; relative risk for high vs. low intake = 0.95; 95% CI = 0.81–1.11) and there was no significant heterogeneity between studies. There was significant heterogeneity between case‐control studies. These results offer some support for the hypothesis that folate has a small protective effect against colorectal cancer but confounding by other dietary factors cannot be ruled out. © 2004 Wiley‐Liss, Inc.
Ultraviolet radiation modulates nuclear factor kappa B activation in human lens epithelial cells
Authors: Boileau Thomas W.‐M. , Bray Tammy M. , Bomser Joshua A. 
Published: October 2004

AbstractExposure to ultraviolet radiation (UVR) is a known risk factor for cataract, but the molecular mechanisms involved have not been elucidated. We hypothesized that exposure to UVR would modulate the activation of nuclear factor kappa‐B (NF‐κB) within the human lens epithelium, since NF‐κB is a key regulator of cellular responses to UVR stress in other cell types. Human lens epithelial (HLE) cells were exposed to acute physiological doses of ultraviolet A (UVAR), B (UVBR), C (UVCR) radiation, or interleukin‐1β (IL‐1β) and NF‐κB activation was measured by electrophoretic shift assay (EMSA). Phosphorylation of IκB in response to UVAR was measured by Western blotting. Irradiation of HLE cells with UVAR (0–1100 J/m2) did not reduce cell survival, while UVBR (400–1600 J/m2) and UVCR (300–900 J/m2) significantly reduced HLE cell survival. EMSA analysis of HLE nuclear proteins indicated activation of NF‐κB, but not activator protein‐1 (AP‐1), by UVAR. The effects of UVBR and UVCR were less pronounced. Exposure of HLE cells to UVAR (0–900 J/m2) followed by a 30‐min incubation resulted in a dose‐dependent activation of NF‐κB. UVAR‐induced NF‐κB activation in HLE cells was evident 10 min postirradiation, maximal at 60 min and returned to control levels by 120 min. Western blot analysis of phosphorylation of the NF‐κB inhibitory protein, IκB, revealed that UVAR activates NF‐κB via a mechanism involving the phosphorylation of IκB‐α; this effect was dose‐dependent. Supershift analysis demonstrated that UVAR and IL‐1β activate the transcriptionally active p65/p50 NF‐κB dimer. These studies demonstrate that UVAR activates NF‐κB in HLE cells in a time‐ and dose‐dependent manner via signaling through IκB‐α. The activation of NF‐κB in HLE cells by UVAR may have implications for the development and progression of cataract and other related ocular disorders.© 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:108–113, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10067
Signal transduction events in lung injury induced by 2‐chloroethyl ethyl sulfide, a mustard analog
Authors: Chatterjee Diptendu , Mukherjee Shyamali , Smith Milton G. , Das Salil K. 
Published: October 2004

AbstractSulfur mustard has been used as a vesicant chemical warfare agent. To understand the mechanism by which mustard gas exposure causes respiratory damage, we have used 2‐chloroethyl ethyl sulfide (CEES) as a mustard analog. Our initial studies have shown that guinea pigs exposed to CEES intratracheally accumulate high levels of TNF‐α. Accumulation of TNF‐α leads to activation of both acid and neutral sphingomyelinases, resulting in high accumulation of ceramides, a second messenger involved in cell apoptosis. In addition, NF‐κB was activated for a short period (1–2 h after exposure) as determined by mobility shift assay. Supershift assays indicated that both p50 and p65 of NF‐κB were activated due to CEES exposure. However, NF‐κB rapidly disappeared after 2 h. It is possible that the initial activation of NF‐κB was an adaptive response to protect the cells from damage since NF‐κB is known to inhibit TNF‐α/ceramide‐induced cell apoptosis. Since NF‐κB disappeared after 2 h, the cells continued being damaged owing to accumulation of ceramides and activation of several caspases, leading to apoptosis. © 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:114–121, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10068
A serotonin receptor antagonist induces oocyte maturation in both frogs and mice: Evidence that the same G protein‐coupled receptor is responsible for maintaining meiosis arrest in both species
Authors: Sheng Yinglun , Wang Ling , Liu X. Shawn , Montplaisir Véronique , Tiberi Mario , Baltz Jay M. , Liu X. Johné 
Published: October 2004

AbstractAccumulating evidence has indicated that vertebrate oocytes are arrested at late prophase (G2 arrest) by a G protein coupled receptor (GpCR) that activates adenylyl cyclases. However, the identity of this GpCR or its regulation in G2 oocytes is unknown. We demonstrated that ritanserin (RIT), a potent antagonist of serotonin receptors 5‐HT2R and 5‐HT7R, released G2 arrest in denuded frog oocytes, as well as in follicle‐enclosed mouse oocytes. In contrast to RIT, several other serotonin receptor antagonists (mesulergine, methiothepine, and risperidone) had no effect on oocyte maturation. The unique ability of RIT, among serotonergic antagonists, to induce GVBD did not match the antagonist profile of any known serotonin receptors including Xenopus 5‐HT7R, the only known Gs‐coupled serotonin receptor cloned so far in this species. Unexpectedly, injection of x5‐HT7R mRNA in frog oocytes resulted in hormone‐independent frog oocyte maturation. The addition of exogenous serotonin abolished x5‐HT7R‐induced oocyte maturation. Furthermore, the combination of x5‐HT7R and exogenous serotonin potently inhibited progesterone‐induced oocyte maturation. These results provide the first evidence that a G‐protein coupled receptor related to 5‐HT7R may play a pivotal role in maintaining G2 arrest in vertebrate oocytes. © 2004 Wiley‐Liss, Inc.
Expression, location, and interactions of ErbB2 and its intramembrane ligand Muc4 (sialomucin complex) in rat mammary gland during pregnancy
Authors: Price‐Schiavi Shari A. , Andrechek Eran , Idris Nebila , Li Peter , Rong Min , Zhang Jin , Carraway Coralie A. Carothers , Muller William J. , Carraway Kermit L. 
Published: October 2004

AbstractMuc4 (also called Sialomucin complex) is a heterodimeric glycoprotein complex consisting of a peripheral O‐glycosylated subunit ASGP‐1 (ascites sialoglycoprotein‐1) tightly but non‐covalently bound to an N‐glycosylated transmembrane subunit ASGP‐2. Muc4/SMC can act as an intramembrane ligand for ErbB2 via an EGF‐like domain present in the transmembrane subunit. The complex is developmentally regulated in normal rat mammary gland and overexpressed in a number of mammary tumors. Overexpression of Muc4/SMC has been shown to block cell–cell and cell–matrix interactions, protect tumor cells from immune surveillance, promote metastasis, and protect from apoptosis. We have investigated whether Muc4/SMC and ErbB2 are co‐expressed and co‐localized in normal rat mammary gland and whether Muc4/SMC–ErbB2 complex formation is developmentally regulated in this tissue. Muc4/SMC and ErbB2 have different expression patterns and regulatory mechanisms in the developing rat mammary gland, but both are maximally expressed during late pregnancy and lactation. The two proteins form a complex in lactating mammary gland which is not detected in the virgin gland. Moreover, this complex does not contain ErbB3. ErbB2 is co‐localized with Muc4/SMC at the apical surfaces of ductal and alveolar cells in lactating gland; however, another form of ErbB2, recognized by a different antibody, localizes to the basolateral surfaces of these cells. ErbB2 phosphorylated on Tyr 1248 co‐localized with Muc4/SMC at the apical surface but not at the basolateral surfaces of these cells. To investigate the function of Muc4 in the mammary gland, transgenic mice were derived using an MMTV‐Muc4 construct. Interestingly, mammary gland development in the transgenic mice was aberrant, exhibiting a bifurcated pattern, including invasion down the blood vessel, similar to that exhibited by transgenic mice inappropriately expressing activated ErbB2 in the mammary gland. These data provide further evidence of the ability of Muc4/SMC to interact with ErbB2 and influence its behavior in normal epithelia. © 2004 Wiley‐Liss, Inc.
Internalization and trafficking of the human and rat growth hormone‐releasing hormone receptor
Authors: Veyrat‐Durebex Christelle , Pomerleau Luc , Langlois Daniel , Gaudreau Pierrette 
Published: October 2004

AbstractInternalization and intracellular trafficking of the growth hormone‐releasing hormone receptor (GHRH‐R) were studied in rat anterior pituitary and human (h) and rat (r) GHRH‐R‐transfected BHK cells, with the GHRH agonist, [Nα‐5‐carboxyfluoresceinyl‐D‐Ala2, Ala8, Ala15, Lys22]hGHRH(1‐29)NH2 (Fluo‐GHRH). Time‐ and temperature‐dependent internalization of stimulated GHRH‐R was blocked by phenyl arsine oxide (PAO) in both cell types. In anterior pituitary and rGHRH‐R‐transfected BHK cells, only filipin III and cerulenin blocked receptor‐mediated internalization of Fluo‐GHRH while in hGHRH‐R‐transfected BHK cells, only hyperosmolar sucrose inhibited this process. These results suggest that hGHRH‐R internalization is clathrin‐dependent, while fatty acid acylation of rGHRH‐R appears to be a prerequisite to caveolin‐dependent internalization. Experiments in anterior pituitary using Bodipy‐FL‐C5 ganglioside GM1, a specific marker of lipid rafts such as caveolae, confirmed this latter pathway. Co‐localization of Fluo‐GHRH with LysoTracker indicated that Fluo‐GHRH was directed to acidic organelles in both cell types. Finally, studies using cycloheximide and monensin showed that upon stimulation with GHRH, an optimal concentration of functional GHRH‐R was maintained at the plasma membrane due to de novo synthesis and recycling in pituitary cells and to de novo synthesis solely in hGHRH‐R‐transfected BHK cells. This first study on the dynamics of the GHRH/GHRH‐R complexes using fluorescence imaging in a native environment compared to cell system models, revealed that both receptor primary structure and concentration at the plasma membrane play important roles in internalization and trafficking of specific G‐protein‐coupled receptors (GPCR). © 2004 Wiley‐Liss, Inc.
Endogenous recovery of injured spinal cord: Longitudinal in vivo magnetic resonance imaging
Authors: Narayana Ponnada A. , Grill Raymond J. , Chacko Tessy , Vang Russell 
Published: October 2004

AbstractPathological changes were followed longitudinally with in vivo magnetic resonance imaging (MRI) and behavioral studies in experimental spinal cord injury (SCI). MRI‐observed pathology was correlated with histology. On MRI, the cavitated regions of the injured cord were gradually filled with viable tissue between two and 8 weeks postinjury, and a concomitant improvement was observed in the neurobehavioral scores. By weeks 3–6, on MRI, the gray matter (GM) returned in the segments caudal, but not rostral, to the injury site. The corresponding histological sections revealed motor neurons as well as other nuclei in the gray matter immediately caudal to the epicenter, but not at the site of injury, suggesting neuronal recovery in perilesioned areas. The neuronal and neurological recovery appeared to occur about the same time as neovasculature that was reported on the contrast‐enhanced MRI, suggesting a role for angiogenesis in recovery from SCI. The role of angiogenesis in neuronal recovery is further supported by the immunohistochemical observation of greater bromodeoxyuridine uptake by blood vessels near the lesion site compared with uninjured cords. © 2004 Wiley‐Liss, Inc.
Differential gene expression in neural stem cells and oligodendrocyte precursor cells: A cDNA microarray analysis
Authors: Hu Jian‐Guo , Fu Sai‐Li , Zhang Kai‐Hua , Li Ying , Yin Lan , Lu Pei‐Hua , Xu Xiao‐Ming 
Published: October 2004

AbstractThe use of neural stem cells (NSCs) or their progeny oligodendrocyte precursor cells (OPCs) represents a promising repair strategy for many neurological disorders. However, the molecular events and biological features during the transition from NSCs to OPCs remain unclear. In the present study, we isolated NSCs from the embryonic rat forebrain and induced them into OPCs by using B104 conditioned medium (B104CM) in vitro. We then employed cDNA array technology to compare changes in gene expression between the two cell populations. Among 1,176 genes examined, 40 were differentially expressed, and some of them may be involved in OPC differentiation from NSCs. Our findings thus provide new insights into the molecular basis of differentiation of OPCs from NSCs. © 2004 Wiley‐Liss, Inc.
High mobility group box protein‐1 inhibits microglial Aβ clearance and enhances Aβ neurotoxicity
Authors: Takata Kazuyuki , Kitamura Yoshihisa , Tsuchiya Daiju , Kawasaki Toshiyuki , Taniguchi Takashi , Shimohama Shun 
Published: October 2004

AbstractOne pathogenic characteristic of Alzheimer's disease (AD) is the formation of extracellular senile plaques with accumulated microglia. According to the amyloid hypothesis, the increase or accumulation of amyloid‐β (Aβ) peptides in the brain parenchyma is the primary event that influences AD pathology. Although the role of microglia in AD pathology has not been clarified, their involvement in Aβ clearance has been noted. High mobility group box protein‐1 (HMGB1) is an abundant nonhistone chromosomal protein. We reported recently that HMGB1 was associated with senile plaques and the total protein level significantly increased in AD brain. In this study, diffuse HMGB1 immunoreactivity was observed around dying neurons in the kainic acid‐ and Aβ1–42 (Aβ42)‐injected rat hippocampi. HMGB1 also colocalized with Aβ in the Aβ42‐injected rats but not in transgenic mice, which show massive Aβ production without neuronal loss in their brains. Furthermore, coinjection of HMGB1 delayed the clearance of Aβ42 and accelerated neurodegeneration in Aβ42‐injected rats. These results suggest that HMGB1 released from dying neurons may inhibit microglial Aβ42 clearance and enhance the neurotoxicity of Aβ42. HMGB1 may thus be another target in the investigation of a therapeutic strategy for AD. © 2004 Wiley‐Liss, Inc.
Detection of lymph node micrometastasis in gastric cancer by MUC2 RT‐PCR: Usefulness in pT1 cases
Authors: Sonoda Hiromichi , Yamamoto Kazuo , Kushima Ryoji , Okabe Hidetoshi , Tani Tohru 
Published: October 2004

AbstractBackground and ObjectivesThe objectives of this study were to evaluate the clinical utility of MUC2‐specific reverse transcriptase‐polymerase chain reaction (RT‐PCR) in gastric cancer patients and to compare MUC2‐specific RT‐PCR to carcinoembryonic antigen (CEA)‐specific RT‐PCR.MethodsA total of 305 lymph nodes from 28 patients with gastric cancer were histologically examined and analyzed by MUC2 RT‐PCR and CEA RT‐PCR.ResultsMUC2 and CEA were expressed in 17.1 and 7.0% of the 286 histologically negative lymph nodes, respectively. The detection rate of MUC2 was significantly higher than that of CEA (P < 0.01). MUC2 RT‐PCR revealed no false positive results in control specimens. Lymph node micrometastases in pT1 gastric cancer were expressed only in perigastric lymph nodes near the tumor and were not detected in tumor less than 30 mm in patients with mucosal cancer.ConclusionsMUC2‐specific RT‐PCR is a sensitive and specific method to detect lymph node micrometastases in gastric cancer patients. The distribution of lymph node micrometastases detected by this method may be useful in minimally invasive procedures for gastric cancer, especially pT1 cases. J. Surg. Oncol. 2004;88:63–70. © 2004 Wiley‐Liss, Inc.
Einsatz keramischer Schneidstoffe in der Stanztechnik
Authors: Schober R. , Loibl D. 
Published: October 2004

AbstractAuf einer Schnellläuferpresse wurden mit einem speziellen Versuchswerkzeug Standmengenuntersuchungen mit Keramikstempeln im Vergleich zu konventionellen Schneidstoffen (Stahl und Hartmetall) bei einem Lochnenndurchmesser von 8,0 mm durchgeführt. Als Blechwerkstoffe wurden Stähle verschiedener Festigkeitsklassen ( 300 bis 900 N/mm2 Zugfestigkeit), eine Aluminium‐ und eine Kupferlegierung eingesetzt.Keramische Schneidstempel erreichen bei allen Versuchsreihen in der Schnittfläche einen höheren Glattschnittanteil ( plus ca. 10 %) und eine höhere Oberflächenqualität in der Glattschnittfläche als Hartmetall‐ oder HSS – Stempel.Reib‐ und Verschleißuntersuchungen nach dem Stift‐Scheibe‐Verfahren unterstützen die Auswahl der Werkzeugwerkstoffe im Tribosystem Schneidstempel/Schmierstoff/Blechwerkstoff. Im Tribosystem Blech/Schmierstoff/Keramik wird die Höhe des Reibungskoeffizienten von der Rauheit, der Orientierung der Ziehrichtung zur Schleifrichtung sowie von Menge und Art des Schmierstoffs beeinflusst. Eine wichtige Voraussetzung für den erfolgreichen Einsatz von keramischen Schneidstempeln ist die keramikgerechte Konstruktion der Werkzeuge sowie eine beanspruchungsgerechte Auswahl der Werkzeugwerkstoffe.
Verhalten PVD‐beschichteter Verzahnungen und Spindellager unter dem Einsatz biologisch abbaubarer Schmierstoffe
Authors: Weck M. , Brecher Chr. , Queins M. , Schlattmeier H. , Reinartz Th. , Bugiel Chr. , Spachtholz G. 
Published: October 2004

AbstractDer nachfolgende Beitrag präsentiert Ergebnisse praxisnaher Untersuchungen mit PVD‐beschichteten Verzahnungen und Spindellagern unter dem Einsatz biologisch schnell abbaubarer und entfeinerter Schmierstoffe. Um das aus der Entfeinerung resultierende Leistungsdefizit und den Verschleißanstieg der Maschinenelemente zu kompensieren, wird im Rahmen des SFB 442 untersucht, inwieweit durch die Verwendung geeigneter Schichtsysteme für die gleit‐ und wälzbeanspruchten Laufflächen die tribologischen Funktionen herkömmlicher, additivierter Fluide auf die PVD‐Schichten übertragen werden können. Das Ziel ist, ein umweltverträgliches System aus Maschinenelement und Schmierstoff zur Verfügung zu stellen, das in seiner Leistungsfähigkeit mindestens den konventionell eingesetzten Varianten entspricht.