bluuebunny/crossref_metadata_2025 huggingface dataset:
Quercetin pharmacokinetics in humans
Authors: Moon Young J. , Wang Liang , DiCenzo Robert , Morris Marilyn E.
Published: February 2008

The purpose of this study was to examine the pharmacokinetics of quercetin aglycone as well as its conjugated metabolites and to develop a population pharmacokinetic model for quercetin that incorporates enterohepatic recirculation. The stability of quercetin in different matrices at various temperatures and pH, and the quercetin content of six capsules of the herbal preparation Quercetin‐500 Plus® were determined by HPLC. Subjects received quercetin 500 mg three times daily and blood and urine samples were obtained. The concentration of quercetin aglycone and conjugated metabolites were assayed using a liquid chromatography‐tandem mass spectrometry assay. Pharmacokinetic parameters were determined using noncompartmental analysis with WinNonlin. A population compartment model incorporating input from the gallbladder was developed to account for the enterohepatic recirculation observed with quercetin. The oral clearance (CL/F) was high (3.5 × 104l/h) with an average terminal half‐life of 3.5 h for quercetin. The plasma concentration versus time curves exhibited re‐entry peaks. A one‐compartment model that included enterohepatic recirculation best described the plasma data. This represents the first comprehensive evaluation of the pharmacokinetics and enterohepatic recirculation of quercetin in humans. Population pharmacokinetic models adapted for enterohepatic recirculation allowed an assessment of the magnitude and frequency of the enterohepatic recirculation process. Copyright © 2008 John Wiley & Sons, Ltd.
Setup and dosimetry for exposing anaesthetised pigs in vivo to 900 MHz GSM mobile phone fields
Authors: Toivonen Tommi , Toivo Tim , Pitkäaho Risto , Puranen Lauri , Silfverhuth Minna , Mennander Ari , Hannula Markus , Hyttinen Jari , Jokela Kari
Published: February 2008

The aim of this study was a dosimetrical analysis of the setup used in the exposure of the heads of domestic pigs to GSM‐modulated radio frequency electromagnetic fields (RF‐EMF) at 900 MHz. The heads of pigs were irradiated with a half wave dipole using three different exposure routines; short bursts of 1–3 s at two different exposure levels and a continuous 10‐min exposure. The electroencephalogram (EEG) was registered continuously during the exposures to search for RF‐EMF originated changes. The dosimetry was based on simulations with the anatomical heterogeneous numerical model of the pig head. The simulation results were validated by experimental measurements with the exposure dipole and a homogeneous liquid phantom resembling the pig head. The specific absorption rate (SAR), defined as a maximum average over 10 g tissue mass (SAR10g), was 7.3 W/kg for the first set of short bursts and 31 W/kg for the second set of short bursts. The SAR10g in the continuous 10‐min exposure was 31 W/kg. The estimated uncertainty for the dosimetry was ±25% (K = 2). Bioelectromagnetics 29:363–370, 2008. © 2008 Wiley‐Liss, Inc.
Enhancement of biogenic sulfide production in a packed‐bed bioreactor via critical inoculum design and carrier material selection
Authors: McMahon Matthew J.L. , Daugulis Andrew J.
Published: February 2008

Sulfate reducing bacteria (SRB) are commonly used in environmental bioprocesses for the treatment of acid mine drainage and sulfate wastewaters. Biogenic H2S is also a potential source of H2 fuel with the recent development of H2S splitting technologies. In this study, a sulfate reducing packed bed bioreactor (PBR) capable of rapidly achieving high volumetric productivities was developed using a novel method of rational inoculum design and the selection of improved biomass carrier materials. An inoculum with initial composition of ∼95% Desulfovibrio desulfuricans (ATCC 7757) and 5% SRB consortium was designed based on the pure strain's superior immobilization potential and the SRB consortium's superior kinetics. Diatomaceous earth (DE) pellets, porous glass beads, polyurethane foam and bone char were evaluated as potential biomass carrier materials. The DE pellets immobilized the most biomass and were employed in two packed bed bioreactor fermentations. Using the designed inoculum and DE pellets, a packed bed bioreactor achieved a volumetric productivity of 493 mol H2S m−3 day−1 (based on a 308 mL working volume) with a dissolved sulfide concentration of 9.9 mM. This occurred after 8.3 days of operation and represents a tenfold reduction in the start‐up period compared to other sulfate reducing PBRs described in the literature. Biotechnol. Bioeng. 2008;100: 855–863. © 2008 Wiley Periodicals, Inc.
Synthesis and Biological Evaluation of Isosteric Analogues of FK866, an Inhibitor of NAD Salvage
Authors: Galli Ubaldina , Ercolano Emanuela , Carraro Lorenzo , Blasi Roman Cintia R. , Sorba Giovanni , Canonico Pier Luigi , Genazzani Armando A. , Tron Gian Cesare , Billington Richard A.
Published: February 2008

One of the great challenges of medicinal chemistry is to create novel, effective, chemotherapeutic agents that show specificity for cancer cells combined with low systemic toxicity. A novel idea is to target the enzymes of the NAD biosynthesis and recycling pathways given that cancer cells display a higher NAD turnover rate than healthy cells. To this end, the compound FK866 (APO866; (E)‐N‐[4‐(1‐benzoylpiperidin‐4‐yl) butyl]‐3‐(pyridin‐3‐yl) acrylamide), which blocks nicotinamide phosphoribosyltransferase (NMPRTase) has entered clinical trials as a potential chemotherapeutic agent. Here we report the synthesis of analogues of FK866 synthesized by click chemistry.
Ontogeny of altered dendritic morphology in the rat prefrontal cortex, hippocampus, and nucleus accumbens following Cesarean delivery and birth anoxia
Authors: Juárez Ismael , Gratton Alan , Flores Gonzalo
Published: February 2008

We used a delayed Cesarean birth model and the Golgi–Cox staining method to investigate the effects of perinatal anoxia on prefrontal cortex (PFC) and hippocampal (CA1) pyramidal neurons as well as nucleus accumbens (NAcc) medium spiny neurons. Dendritic morphology in these regions was studied on postnatal days (P) 2, 7, 14, 21, 35, and 70 in male Sprague–Dawley rats born either vaginally (VAG) or by Cesarean section either with (C + anoxia) or without (C‐only) anoxia. The most striking birth group differences seen were at the level of dendritic spine densities on P35. During this postnatal period the dendritic spine density of PFC neurons was significantly lower in C + anoxia and C‐only animals than in VAG controls; however, by P70 PFC spine densities in all birth groups were comparable. In contrast, hippocampal spine densities on P35 were comparably greater in C + anoxia animals than in VAG controls, whereas in C‐only animals spine densities were lower than controls; here again, by P70 all groups had comparable hippocampal spine densities. In NAcc greater spine densities were seen on medium spiny neurons of C + anoxia animals on P35. These findings provide evidence that perinatal insult in the form of Cesarean birth with or without anoxia alters the dendritic development of PFC and hippocampal pyramidal neurons and to some extent also of NAcc medium spiny neurons. They also suggest that perinatal anoxia can alter the neuronal development of key structures thought to be affected in such late‐onset dopamine‐related disorders as schizophrenia and Attention Deficit Hyperactivity Disorder (ADHD). J. Comp. Neurol. 507:1734–1747, 2008. © 2008 Wiley‐Liss, Inc.
The Growth of Co:ZnO/ZnO Core/Shell Colloidal Quantum Dots: Changes in Nanocrystal Size, Concentration and Dopant Coordination
Authors: Lommens Petra , Lambert Karel , Loncke Frank , De Muynck David , Balkan Timuçin , Vanhaecke Frank , Vrielinck Henk , Callens Freddy , Hens Zeger
Published: February 2008

We report a synthesis route for the growth of Co:ZnO/ZnO core/shell quantum dots. This procedure consists of successive steps, comprising the addition of diluted precursor salt solutions, and heat treatment at 50 °C. By deriving a relation between the extinction coefficient at 250 nm and the nanocrystal diameter, we are able to monitor changes in quantum dot concentration during shell growth. We found that a mechanism based on the nucleation of new particles after salt addition and subsequent Ostwald ripening during the heat treatment is responsible for the shell growth. Based on ligand‐field absorption spectroscopy, we demonstrate that the Co2+ ions adsorbed at the surface of Co:ZnO quantum dots are incorporated inside the ZnO shells. Finally, EPR spectroscopy indicates that the surface‐adsorbed Co2+ ions can be incorporated as substitutional as well as interstitial Co2+ ions.
A DC/DC converter topology for renewable energy systems
Authors: Chiu Huang‐Jen , Yao Chun‐Jen , Lo Yu‐Kang
Published: February 2008

This paper presents a DC/DC converter topology for renewable energy systems. The proposed DC/DC converter can be used to obtain a well‐regulated output voltage from low‐voltage power source, such as wind turbine, photovoltaic array, fuel cell, etc. It has the merits of high efficiency, low device stresses, and low current ripple. The operating principle, theoretical analysis, and design criteria are provided in this paper. A laboratory prototype was successfully implemented. The simulation and experimental results are given to verify the feasibility of the proposed scheme. Copyright © 2008 John Wiley & Sons, Ltd.
CD40 ligation decreases its protein half‐lifeat the cell surface
Authors: Tucker Torry A. , Schwiebert Lisa M.
Published: February 2008

CD40 is expressed on a variety of tumors; anti‐CD40 agonists promote tumor cell apoptosis and subsequent tumor regression. Because the effectiveness of anti‐CD40‐ agonists is dependent upon CD40 surface expression, the current study examined ligation‐mediated changes in CD40 protein half‐life (t1/2) at the cell surface. This study utilized a CD40+ epithelial cell line (9HTEo‐), a CD40 null epithelial cell line (HT‐29) engineered to express either wild‐type (WT) or mutant (T254A, Q263A, E235A, Δ201) CD40, and the anti‐CD40 antibody G28.5. Ligation of endogenous CD40 expressed on 9HTEo‐ cells decreased CD40 surface protein t1/2 from 13 to 4 h (p <0.05). Ligation of WT‐, Q263A‐, or T254A‐CD40 expressed on engineered HT‐29 cells decreased CD40 surface protein t1/2 from an average of 8 to 4 h (p <0.05); T254A and Q263A contain mutated TNF receptor‐associated factor (TRAF)2/3‐binding sites. In contrast, ligation of E235A and Δ201‐CD40 had no affect on its surface protein t1/2 (p <0.05); E235A contains a mutated TRAF6‐binding site while Δ201 lacks an intact cytoplasmic tail. These results suggest that anti‐CD40 agonists decrease CD40 surface protein t1/2 via a mechanism that involves TRAF6 but not TRAF2/3. The therapeutic implications for CD40‐mediated tumor regression are discussed.
Preparation and X‐ray Structures of TiIV Complexes of Bis(carboxylato) Ligands – Formation of Mono‐, Di‐, Tetra‐, and Hexanuclear Complexes with or without OR and μ‐O Ligands
Authors: Shavit Michal , Tshuva Edit Y.
Published: February 2008

Treating the amine bis(carboxylato) ligand precursor pyridine‐2,6‐dicarboxylic acid (H2L1) with titanium tetra(isopropoxide) gave the mononuclear octacoordinate complex L12TiIV(dmf)2 (1), in which each carboxylato ligand binds in an η1 fashion and two solvent molecules are also coordinated to the metal. In contrast, employing the diamine bis(carboxylic acid) ligand precursor H2L2 gave a unique hexanuclear TiIV complex [TiIV6(OiPr)16(μ2‐OiPr)4(μ‐L2)2] (2), where L2 = (pyridin‐2‐ylmethyl)amino diacetate. The crystal structure reveals that all TiIV atoms exhibit octahedral geometry, where both carboxylate and isopropoxide groups serve as bridging ligands. Surprisingly, no oxido ligands appear in the structure, which indicates that the complex, obtained at room temp., was not exposed to any traces of water. The diamine bis(carboxylato) ligand coordinates in η2 modes of both carboxyl groups to give a total of six coordination sites. Employing the same ligand with a slight change in reaction conditions, which included heating to 35 °C, led to the formation of two O‐bridged complexes: dinuclear [TiIV2(μ2‐O)(OiPr)2(L2)2] (3) and tetranuclear [TiIV4(μ2‐O)4(L2)4] (4), where each bis(carboxylato) ligand binds to a single Ti center in an η1 fashion, and the only bridging ligands are oxide groups, with Ti–O–Ti angles of 180.0° and 166.6° for 3 and 4, respectively, indicating π interactions in the dinuclear species. Employing a different diamine bis(carboxylato) ligand featuring a sequential connectivity of donor atoms allowed the identification of a mononuclear C2‐symmetrical bis(isopropoxido) complex, L3TiIV(OiPr)2, (5) where L3 = ethylenediamine diacetate. In 5, as opposed to 2 and similarly to 1, 4, and 5, the carboxylato ligand binds in an η1 fashion. Complexes 3, 4, and 5 are all inactive against ovarian OVCAR‐1 and colon HT‐29 cells. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Sequence of Metal‐Organic Oligomer‐Polymer Exchange Equilibria in Solution: Supramolecular Isomerism, Self‐Assembly Dynamics and Carboxylate Shift of Di‐n‐butyltin cis‐1,4‐Cyclohexanedicarboxylate
Authors: Hernández‐Ahuactzi Irán Fernando , Cruz‐Huerta Jorge , Barba Victor , Höpfl Herbert , Zamudio‐Rivera Luis S. , Beltrán Hiram I.
Published: February 2008

Di‐n‐butyltin dichloride (nBu2SnCl2) was treated with the potassium salt of cis‐1,4‐cyclohexanedicarboxylate (cis‐1,4‐chdcaK2) to give di‐n‐butyltin cis‐1,4‐cyclohexanedicarboxylate. In the solid state two supramolecular isomers coexist within the same crystal lattice, the 36‐membered macrocyclic tetranuclear complex [{nBu2Sn(cis‐1,4‐chdca)}4] and the analogous polymeric form [{nBu2Sn(cis‐1,4‐chdca)}n]. In solution, fast (on the NMR time scale) dynamic equilibria were detected. The supramolecular arrangement in the solid state consists of alternating macrocycle and polymer ribbons with different patterns of intermolecular Sn···O interactions that give rise to a total of four different types of supramolecular macrocyclic assemblies. They probably resemble local environments in the liquid phase and allow to propose a plausible mechanistic pathway for the ring‐chain rearrangement dynamics during which the macrocycle molecules are transformed into other macrocyclic and polymeric molecules.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Reinforced concrete beam–column joints with crossed inclined bars under cyclic deformations
Authors: Chalioris Constantin E. , Favvata Maria J. , Karayannis Chris G.
Published: February 2008

This experimental study investigates the effectiveness of crossed inclined bars (X‐bars) as joint shear reinforcement in exterior reinforced concrete beam–column connections under cyclic deformations. Test results of 20 joint subassemblages with various reinforcement ratios and arrangements including X‐bars in the joint area are presented. The X‐type, non‐conventional reinforcement is examined as the only joint reinforcement and in combination with common stirrups or vertical bars. The experimental results reported herein include full loading cycle curves, energy dissipation values and a categorization of the observed damage modes. Based on the comparisons between the overall hysteretic responses of the tested specimens, it is deduced that joints with X‐bars exhibited enhanced cyclic performance and improved damage mode since a distinct flexural hinge was developed in the beam–joint interface. Further, the combination of crossed inclined bars and stirrups in joint area resulted in enhanced hysteretic response and excellent performance capabilities of the specimens. However, in some specimens with X‐bars as the only joint shear reinforcement, the deformations of the bent anchorage of the beam's bars caused considerable damages at the back of the joint area. Discussion for a potential replacement of the joint stirrups with X‐type reinforcement in some cases of exterior joints is also included. Copyright © 2008 John Wiley & Sons, Ltd.
Stability analysis of SDOF real‐time hybrid testing systems with explicit integration algorithms and actuator delay
Authors: Chen Cheng , Ricles James M.
Published: February 2008

Earthquake Engng Struct. Dyn. 2007 (DOI: 10.1002/eqe.775)

The above article (DOI: 10.1002/eqe.775) was published online on 10 December 2007 in Wiley InterScience (www.interscience.wiley.com). A number of imperfections were subsequently identified and have been corrected below. The print publication will incorporate the amendments identified by this erratum notice.

Figure 2 has been corrected as follows:

2.

magnified image

2.

Figure 6 has been corrected as follows:

6.

magnified image

6.

Figure 7 has been corrected as follows:

7.

magnified image

7.

Figure 8 has been corrected as follows:

8.

magnified image

8.

Figure 9 has been corrected as follows:

9.

magnified image

9.

Figure 10 has been corrected as follows:

10.

magnified image

10.
Decadal and century‐long changes in the reconstruction of erosive rainfall anomalies in a Mediterranean fluvial basin
Authors: Diodato N. , Ceccarelli M. , Bellocchi G.
Published: February 2008

Rain erosivity is difficult to reconstruct for past periods due to the few long detailed instrumental series. This paper deals with the potential of written historical documents to reconstruct yearly erosive rain anomalies (differences between erosivity values and long‐term average). A detailed analysis was undertaken of the Calore River Basin (South Italy) erosive rainfall using data from 425‐year‐long series of both observations (1922–2004) and proxy‐based reconstructions (1580–1921).

Annual erosivity was computed for the observational time based on the Revised Universal Soil Loss Equation (RUSLE) scheme, whilst documentary descriptions described the course of rain events for the previous times. A method was proposed that uses a weather index to account for the abundance of weather anomalies (rainfall extremes) as registered in historical documents. A model was developed to provide annual rain‐erosivity data comparable with the RUSLE scheme, using the weather index sum (June–October) and variance (January–December) and the annual precipitation amount as inputs. This model was applied to reconstruct annual rain‐erosivity anomalies for the pre‐modern instrumental time. A long continuous series of rain‐erosivity anomalies was produced by combining (and homogenizing) model‐reconstructed and RUSLE data, thus providing a range of natural variability in climate erosivity to detect the main changes from 1580 to 2004. The climate history of the Calore River Basin shows pronounced interdecadal variations, with multidecadal erosivity reflecting the mixed population of thermoconvective and cyclonic rainstorms with large anomalies. The so‐called Little Ice Age (16th to mid‐19th centuries) was identified as the stormiest period, with mixed rainstorm types and high frequency of floods and erosive rainfall. Important historical climate fluctuations were observed, but with a relevant smoothing in the last 150 years of the series. For the recent, warm period, investigations at higher time resolution are required to assess the seasonal changes of rain erosivity and their relationship to soil conservation. Copyright © 2008 John Wiley & Sons, Ltd.
Information revelation in the futures market: Evidence from single stock futures
Authors: Shastri Kuldeep , Thirumalai Ramabhadran S. , Zutter Chad J.
Published: February 2008

This paper analyzes 31 months of data on 137 single‐stock futures (SSFs) traded on OneChicago. The results indicate that on the days they trade, SSFs contribute approximately 24% of the price discovery for underlying stocks. Information revelation in the SSFs market decreases with the ratio of spreads in the futures and the stock markets and the volatility in the stock market. Moreover, the quality of the market for the underlying stocks improves substantially after the introduction of the SSFs market, with the largest improvement occurring on days with SSFs trading. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:335– 353, 2008
Capacitative calcium entry and transient receptor potential canonical 6 expression control human hepatoma cell proliferation
Authors: El Boustany Charbel , Bidaux Gabriel , Enfissi Antoine , Delcourt Philippe , Prevarskaya Natalia , Capiod Thierry
Published: February 2008

Store-operated calcium entry (SOCE) is the main Ca2+ influx pathway involved in controlling proliferation of the human hepatoma cell lines Huh-7 and HepG2. However, the molecular nature of the calcium channels involved in this process remains unknown. Huh-7 and HepG2 cells express transient receptor potential canonical 1 (TRPC1) and TRPC6, as well as STIM1 and Orai1, and these 4 channels are the most likely candidates to account for the SOCE in these cells. We generated stable TRPC6-overexpressing or TRPC6-knockdown Huh-7 clones, in which we investigated correlations between the presence of the protein, the rate of cell proliferation, and SOCE amplitude. TRPC6-overexpressing Huh-7 cells proliferated 80% faster than did untransfected cells and their SOCE amplitude was 160% higher. By contrast, proliferation rate was 50% lower and SOCE amplitude 85% lower in TRPC6-knockdown clones than in untransfected cells. OAG (olyl acetyl glycerol)-induced calcium entry was similar in all cells, and small interfering RNA (siRNA) against TRPC1 had no effect on SOCE amplitude, highlighting the relationship among SOCE, TRPC6 and cell proliferation in Huh-7 cells. SOCE amplitude was reduced by STIM1 and Orai1 knockdowns, suggesting possible cooperation between these proteins and TRPC6 in these cells. Endothelial growth factor and hepatocyte growth factor increased TRPC6 expression and SOCE amplitude in Huh-7 cells, and cyclin D1 expression was decreased by STIM1, Orai1, and TRPC6 knockdowns.

Conclusion:

TRPC6 was very weakly expressed in isolated hepatocytes from healthy patients and expressed more strongly in tumoral samples from the liver of a cancer patient, strongly supporting a role for these calcium channels in liver oncogenesis.
Hepatocyte-specific inhibitor-of-kappaB-kinase deletion triggers the innate immune response and promotes earlier cell proliferation during liver regeneration
Authors: Malato Yann , Sander Leif E. , Liedtke Christian , Al-Masaoudi Malika , Tacke Frank , Trautwein Christian , Beraza Naiara
Published: February 2008

Nuclear factor κB (NF-κB) is one of the main transcription factors involved in liver regeneration after partial hepatectomy (PH). It is activated upon IκB phosphorylation by the IκB kinase (IKK) complex comprising inhibitor of kappaB kinase 1 (IKK1), inhibitor of kappaB kinase 2 (IKK2), and nuclear factor-B essential modifier (NEMO). We studied the impact of hepatocyte-specific IKK2 deletion during liver regeneration. A 70% PH was performed on IKK2f/f (wild-type) and IKK2ΔLPCmice (hepatocyte-specific IKK2 knockout mice). PH in IKK2ΔLPC compared with IKK2f/f mice resulted in weaker and delayed NF-κB activation in hepatocytes, while nonparenchymal liver cells showed earlier NF-κB activation and higher tumor necrosis factor expression. Additionally, these animals showed increased and earlier serum amyloid A and chemotactic cytokine L-1 levels followed by enhanced polymorphonuclear cell recruitment to the liver. These results correlated with earlier Jun kinase activity, c-myc expression, and matrix metalloproteinase-9 activity, suggesting earlier priming in IKK2ΔLPC mice after PH. These data preceded a more rapid cell cycle progression and earlier hepatocyte proliferation as evidenced through cyclin and 5-bromo-2-deoxyuridine analysis. Interestingly, despite faster G1/S progression, IKK2ΔLPC mice exhibited an enduring mitosis phase, because mitotic bodies were still observed at later stages after PH.

Conclusion:

We demonstrate that PH in IKK2ΔLPC mice triggers a more rapid and pronounced inflammatory response in nonparenchymal liver cells, which triggers earlier hepatocyte proliferation.
The hepatitis B virus X protein induces paracrine activation of human hepatic stellate cells
Authors: Martín-Vílchez Samuel , Sanz-Cameno Paloma , Rodríguez-Muñoz Yolanda , Majano Pedro L. , Molina-Jiménez Francisca , López-Cabrera Manuel , Moreno-Otero Ricardo , Lara-Pezzi Enrique
Published: February 2008

Chronic hepatitis B virus (HBV) infection is a major cause of liver fibrosis, eventually leading to cirrhosis and hepatocellular carcinoma. Although the involvement of the X protein of HBV (HBx) in viral replication and tumor development has been extensively studied, little is known about its possible role in the development of fibrosis. In this work we show that expression of HBx in hepatocytes results in paracrine activation and proliferation of hepatic stellate cells (HSCs), the main producers of extracellular matrix proteins in the fibrotic liver. Both human primary HSCs and rat HSCs exposed to conditioned medium from HBx-expressing hepatocytes showed increased expression of collagen I, connective tissue growth factor, α smooth muscle actin, matrix metalloproteinase-2, and transforming growth factor-β (TGF-β), together with an enhanced proliferation rate. We found that HBx induced TGF-β secretion in hepatocytes and that the activation of HSCs by conditioned medium from HBx-expressing hepatocytes was prevented by a neutralizing anti-TGF-β antibody, indicating the involvement of this profibrotic factor in the process.

Conclusion:

Our results propose a direct role for HBx in the development of liver fibrosis by the paracrine activation of stellate cells and reinforce the indication of antiviral treatment in patients with advanced HBV-related chronic liver disease and persistent liver replication.
Molecular mechanisms of death ligand‐mediated immune modulation: A gene therapy model to prolong islet survival in type 1 diabetes
Authors: Sanlioglu Ahter Dilsad , Griffith Thomas S. , Omer Abdulkadir , Dirice Ercument , Sari Ramazan , Altunbas Hasan Ali , Balci Mustafa Kemal , Sanlioglu Salih
Published: February 2008

Type 1 diabetes results from the T cell‐mediated destruction of pancreatic beta cells. Islet transplantation has recently become a potential therapeutic approach for patients with type 1 diabetes. However, islet‐graft failure appears to be a challenging issue to overcome. Thus, complementary gene therapy strategies are needed to improve the islet‐graft survival following transplantation. Immune modulation through gene therapy represents a novel way of attacking cytotoxic T cells targeting pancreatic islets. Various death ligands of the TNF family such as FasL, TNF, and TNF‐Related Apoptosis‐Inducing Ligand (TRAIL) have been studied for this purpose. The over‐expression of TNF or FasL in pancreatic islets exacerbates the onset of type 1 diabetes generating lymphocyte infiltrates responsible for the inflammation. Conversely, the lack of TRAIL expression results in higher degree of islet inflammation in the pancreas. In addition, blocking of TRAIL function using soluble TRAIL receptors facilitates the onset of diabetes. These results suggested that contrary to what was observed with TNF or FasL, adenovirus mediated TRAIL gene delivery into pancreatic islets is expected to be therapeutically beneficial in the setting of experimental models of type 1 diabetes. In conclusion; this study mainly reveals the fundamental principles of death ligand‐mediated immune evasion in diabetes mellitus. J. Cell. Biochem. 104: 710–720, 2008. © 2008 Wiley‐Liss, Inc.
The pro‐osteogenic action of β‐catenin requires interaction with BMP signaling, but not Tcf/Lef transcriptional activity
Authors: Salazar Valerie S. , Mbalaviele Gabriel , Civitelli Roberto
Published: February 2008

The role of β‐catenin in skeletal development and osteogenic cell differentiation is well established, but the molecular mechanisms attending these effects remain largely unknown. We conducted a structure/function analysis of β‐catenin to gain further insights on these mechanisms. Retroviral transduction of a full‐length, constitutively active β‐catenin mutant inhibited adipogenesis and stimulated osteoblast differentiation from multipotent embryonic fibroblasts (C3H10T1/2). However, N‐terminal truncated β‐catenin mutants with weak Tcf/Lef activity retained their pro‐osteogenic action, as did a constitutively stabilized mutant lacking the C‐terminal Tcf/Lef transactivation domain. Importantly, this Tcf/Lef‐defective β‐catenin did not suppress adipogenesis, and even elicited spontaneous adipogenesis when expressed in cells cultured in osteogenic conditions. Thus, Tcf/Lef transcriptional activity of β‐catenin is critical for inhibition of adipogenesis, while it is dispensable for its pro‐osteogenic effect. BMP‐2 greatly enhanced both osteogenesis and adipogenesis in the presence of the C‐terminally truncated mutant, though it selectively enhanced only osteoblast differentiation in cells transduced with the full‐length, Tcf/Lef active β‐catenin mutant. C3H10T1/2 cells produce BMP‐4, and inhibition of endogenous BMP signaling by Noggin curtailed osteogenic differentiation by constitutively active β‐catenin. Therefore, BMP signaling must be active for full induction by β‐catenin of osteogenic differentiation from multipotent precursors. These data suggest that cooperative interactions between β‐catenin and BMP signaling systems drive osteoblast cell fate specification and differentiation. J. Cell. Biochem. 104: 942–952, 2008. © 2008 Wiley‐Liss, Inc.
A proteomic study reveals the diversified distribution of plasma membrane‐associated proteins in rat hepatocytes
Authors: Li Xuanwen , Cao Jia , Jin Qihui , Xie Chunliang , He Quanyuan , Cao Rui , Xiong Jixian , Chen Ping , Wang Xianchun , Liang Songping
Published: February 2008

To investigate the heterogeneous protein composition of highly polarized hepatocyte plasma membrane (PM), three PM‐associated subfractions were obtained from freshly isolated rat hepatocytes using density gradient centrifugation. The origins of the three subfractions were determined by morphological analysis and western blotting. The proteins were subjected to either one‐dimensional (1‐D) SDS–PAGE or two‐dimensional (2‐D) benzyldimethyl‐n‐hexadecylammonium chloride (BAC)/SDS–PAGE before nano‐Liquid Chromatography‐Electrospray Ionization—tandem mass spectrometry analysis (LC‐ESI‐MS/MS). A total of 613 non‐redundant proteins were identified, among which 371 (60.5%) proteins were classified as PM or membrane‐associated proteins according to GO annotations and the literatures and 32.4% had transmembrane domains. PM proteins from microsomal portion possessed the highest percentage of transmembrane domain, about 46.5% of them containing at least one transmembrane domain. In addition to proteins known to be located at polarized liver PM regions, such as asialoglycoprotein receptor 2, desmoplakin and bile salt export pump, several proteins which had the potential to become novel subfraction‐specific proteins were also identified, such as annexin a6, pannexin and radixin. Our analysis also evaluated the application of 1‐D SDS–PAGE and 2‐D 16‐BAC/SDS–PAGE on the separation of integral membrane proteins. J. Cell. Biochem. 104: 965–984, 2008. © 2008 Wiley‐Liss, Inc.
Involvement of the role of Chk1 in lithium‐induced G2/M phase cell cycle arrest in hepatocellular carcinoma cells
Authors: Wang Xiao‐Ming , Li Jiao , Feng Xiao‐Cheng , Wang Qiong , Guan Dong‐Yin , Shen Zong‐Hou
Published: February 2008

Lithium, a therapeutic agent for bipolar disorder, can induce G2/M arrest in various cells, but the mechanism is unclear. In this article, we demonstrated that lithium arrested hepatocellular carcinoma cell SMMC‐7721 at G2/M checkpoint by inducing the phosphorylation of cdc2 (Tyr‐15). This effect was p53 independent and not concerned with the inhibition of glycogen synthase kinase‐3 and inositol monophosphatase, two well‐documented targets of lithium. Checkpoint kinase 1 (Chk1), a critical enzyme in DNA damage‐induced G2/M arrest, was at least partially responsible for the lithium action. The lithium‐induced phosphorylation of cdc2 and G2/M arrest was abrogated largely by SB218078, a potent Chk1 inhibitor, as well as by Chk1 siRNA or the over‐expression of kinase dead Chk1. Furthermore, lithium‐induced cdc25C phosphorylation in 7721 cells and in vitro kinase assay showed that the activity of Chk1 was enhanced after lithium treatment. Interestingly, the increase of Chk1 activity by lithium may be independent of ataxia telangiectasia mutated (ATM)/ATM and Rad3‐related (ATR) kinase. This is because no elevated phosphorylation on Chk1 (Ser‐317 and Ser‐345) was observed after lithium treatment. Moreover, caffeine, a known ATM/ATR kinase inhibitor, relieved the phosphorylation of cdc2 (Tyr‐15) by hydroxyurea, but not that by lithium. Our study's results revealed the role of Chk1 in lithium‐induced G2/M arrest. Given that Chk1 has been proposed to be a novel tumor suppressor, we suggest that the effect of lithium on Chk1 and cell cycle is useful in tumor prevention and therapy. J. Cell. Biochem. 104: 1181–1191, 2008. © 2008 Wiley‐Liss, Inc.
Dimorphic expression of uncoupling protein‐3 in golden hamster harderian gland: Effects of castration and testosterone administration
Authors: Santillo Alessandra , Monteforte Rossella , De Lange Pieter , Lanni Antonia , Farina Paola , Baccari Gabriella Chieffi
Published: February 2008

Hamster (Mesocricetus auratus) harderian gland (HG) is a dimorphic orbital gland producing a copious lipid secretion. Two cell‐types are present in hamster HG, type I in both sexes, type II only in males. In hamster HGs, we found a marked sexual dichotomy in the expression of uncoupling protein‐3 (UCP3), a mitochondrial protein carrier, that probably exports fatty acid anions and fatty acid peroxides from the mitochondrial matrix. Following castration and/or testosterone treatment: (1) UCP3 levels correlated with the type II‐cell percentage, not with testosterone levels, (2) in male HGs, UCP3 was comparable to female levels at 30 days post‐castration (when the type II‐cell percentage had fallen from 50 to 5%), although testosterone was already near zero at 15 days (when neither the type II‐cell percentage nor the UCP3 level had fallen), and testosterone‐replacement therapy prevented these changes. Testosterone‐treated females possessed type II cells and a UCP3 level about twofold higher than in control females. Males displayed more intense UCP3 immunohistochemical positivity in type I HG cells than females. Hence, testosterone may indirectly control UCP3 expression by regulating the gland's morphological and lipid dimorphism. Straight‐chain fatty acids [found in alkyl diacylglycerols (ADGs) in males] are oxidized predominantly in mitochondria, branched‐chain fatty acids (abundant in ADGs in females) predominantly in peroxisomes, so we speculate that the higher UCP3 expression in males reflects greater fatty acid flux in HG mitochondria. This is supported by our finding that in female (not male) HGs, the peroxisome‐rich fraction contained α‐methylacyl‐CoA racemase (AMACR), an enzyme important in the β‐oxidation of branched‐chain fatty acids. J. Cell. Physiol. 215: 481–487, 2008. © 2008 Wiley‐Liss, Inc.
L‐ and N‐current but not M‐current inhibition by M1 muscarinic receptors requires DAG lipase activity
Authors: Liu Liwang , Heneghan John F. , Michael Gregory J. , Stanish Lee F. , Egertová Michaela , Rittenhouse Ann R.
Published: February 2008

Stimulation of postsynaptic M1 muscarinic receptors (M1Rs) increases firing rates of both sympathetic and central neurons that underlie increases in vasomotor tone, heart rate, and cognitive memory functioning. At the cellular level, M1R stimulation modulates currents through various voltage‐gated ion channels, including KCNQ K+ channels (M‐current) and both L‐ and N‐type Ca2+ channels (L‐ and N‐current) by a pertussis toxin‐insensitive, slow signaling pathway. Depletion of phosphatidylinositol‐4,5‐bisphosphate (PIP2) during M1R stimulation suffices to inhibit M‐current. We found previously that following PIP2 hydrolysis by phospholipase C, activation of phospholipase A2 and liberation of a lipid metabolite, most likely arachidonic acid (AA) are necessary for L‐ and N‐current modulation. Here we examined the involvement of a third lipase, diacylglycerol lipase (DAGL), in the slow pathway. We documented the presence of DAGL in superior cervical ganglion neurons, and then tested the highly selective DAGL inhibitor, RHC‐80267, for its capacity to antagonize M1R‐mediated modulation of whole‐cell Ca2+ currents. RHC‐80267 significantly reduced L‐ and N‐current inhibition by the muscarinic agonist oxotremorine‐M (Oxo‐M) but did not affect their inhibition by exogenous AA. Moreover, voltage‐dependent inhibition of N‐current by Oxo‐M remained in the presence of RHC‐80267, indicating selective action on the slow pathway. RHC also blocked inhibition of recombinant N‐current. In contrast, RHC‐80267 had no effect on native M‐current inhibition. These data are consistent with a role for DAGL in mediating L‐ and N‐current inhibition. These results extend our previous findings that the signaling pathway mediating L‐ and N‐current inhibition diverges from the pathway initiating M‐current inhibition. J. Cell. Physiol. 216: 91–100, 2008. © 2008 Wiley‐Liss, Inc.
ERα and AP‐1 interact in vivo with a specific sequence of the F promoter of the human ERα gene in osteoblasts
Authors: Lambertini Elisabetta , Tavanti Elisa , Torreggiani Elena , Penolazzi Letizia , Gambari Roberto , Piva Roberta
Published: February 2008

Estrogen‐responsive genes often have an estrogen response element (ERE) positioned next to activator protein‐1 (AP‐1) binding sites. Considering that the interaction between ERE and AP‐1 elements has been described for the modulation of bone‐specific genes, we investigated the 17‐β‐estradiol responsiveness and the role of these cis‐elements present in the F promoter of the human estrogen receptor alpha (ERα) gene. The F promoter, containing the sequence analyzed here, is one of the multiple promoters of the human ERα gene and is the only active promoter in bone tissue. Through electrophoretic mobility shift (EMSA), chromatin immunoprecipitation (ChIP), and re‐ChIP assays, we investigated the binding of ERα and four members of the AP‐1 family (c‐Jun, c‐fos, Fra‐2, and ATF2) to a region located approximately 800 bp upstream of the transcriptional start site of exon F of the human ERα gene in SaOS‐2 osteoblast‐like cells. Reporter gene assay experiments in combination with DNA binding assays demonstrated that F promoter activity is under the control of upstream cis‐acting elements which are recognized by specific combinations of ERα, c‐Jun, c‐fos, and ATF2 homo‐ and heterodimers. Moreover, ChIP and re‐ChIP experiments showed that these nuclear factors bind the F promoter in vivo with a simultaneous occupancy stimulated by 17‐β‐estradiol. Taken together, our findings support a model in which ERα/AP‐1 complexes modulate F promoter activity under conditions of 17‐β‐estradiol stimulation. J. Cell. Physiol. 216: 101–110, 2008. © 2008 Wiley‐Liss, Inc.
The c‐myc apoptotic response is not intrinsic to blocking terminal myeloid differentiation
Authors: D'Angelo Santo , Liebermann Dan , Hoffman Barbara
Published: February 2008

It has previously been shown that deregulated c‐myc blocks terminal myeloid differentiation and prematurely recruits both the Type I and II CD95/Fas apoptotic pathways, promoting an incompletely penetrant apoptotic response. In this work it is shown that deregulated expression of either mycER or mycER™ variants also blocked terminal myeloid differentiation but failed to induce the apoptotic response, demonstrating that c‐myc can block differentiation independent of the apoptotic response. The failure of the mycER™ transgene to cause the apoptotic response is associated with reduced levels of RIP1 expression, increased Mcl‐1 expression and activation of both NF‐kB and Akt. In addition, deregulating expression of RIP1 in M1mycER™ cells restored the apoptotic response. Thus altering c‐Myc or its downstream effectors can influence the balance between apoptosis and survival, and ultimately the oncogenic potential of the c‐myc oncogene. This knowledge can be exploited to manipulate the downstream effectors, such as RIP1, to promote apoptosis and drive the death of cancer cells. J. Cell. Physiol. 216: 120–127, 2008. © 2008 Wiley‐Liss, Inc.
BMP‐2 regulation of PTHrP and osteoclastogenic factors during osteoblast differentiation of C2C12 cells
Authors: Susperregui Antonio R.G. , Viñals Francesc , Ho Patricia W.M. , Gillespie Matthew T. , Martin T. John , Ventura Francesc
Published: February 2008

Bone morphogenetic protein‐2 (BMP‐2) is strongly involved in the induction of osteoblast differentiation from mesenchymal cell precursors, as well as in enhancing bone matrix production by osteoblastic cells. Likewise, the osteoporotic phenotype of PTHrP deficient mice makes clear the importance of this paracrine regulator in bone physiology. Here, we report that BMP‐2 rapidly down‐regulated PTHrP gene expression through a transcriptional mechanism in pluripotent mesenchymal C2C12 cells, whereas BMP‐2 increased expression of PTHrP receptor. PTHrP did not significantly alter the BMP‐dependent Smad transcriptional pathway. Similarly, PTHrP did not significantly modify the BMP‐regulated expression of RANKL or OPG, cytokines involved in osteoclastogenesis. More importantly, addition of PTHrP, through the PKA signaling pathway, partially prevented the BMP‐dependent induction of some osteogenic markers such as Runx2 and Osterix in C2C12 cells. Our data suggest that BMP‐2 down‐regulation of PTHrP could facilitate terminal differentiation of osteoblasts. J. Cell. Physiol. 216: 144–152, 2008. © 2008 Wiley‐Liss, Inc.
Transcriptional profiling defines the roles of ERK and p38 kinases in epidermal keratinocytes
Authors: Gazel Alix , Nijhawan Rajiv I. , Walsh Rebecca , Blumenberg Miroslav
Published: February 2008

Epidermal keratinocytes respond to extracellular influences by activating cytoplasmic signal transduction pathways that change gene expression. Using pathway‐specific transcriptional profiling, we identified the genes regulated by two such pathways, p38 and ERK. These pathways are at the fulcrum of epidermal differentiation, proliferative and inflammatory skin diseases. We used SB203580 and PD98059 as specific inhibitors and Affymetrix Hu133Av2 microarrays, to identify the genes regulated after 1, 4, 24, and 48 h and compared them to genes regulated by JNK. Unexpectedly, inhibition of MAPK pathways is compensated by activation of the NFκB pathway and suppression of the DUSP enzymes. Both pathways promote epidermal differentiation; however, there is a surprising disconnect between the expression of steroid synthesis enzymes and differentiation markers. The p38 pathway induces the expression of extracellular matrix and proliferation‐associated genes, while suppressing microtubule‐associated genes. The ERK pathway induces nuclear envelope and mRNA splicing proteins, while suppressing steroid synthesis and mitochondrial energy production enzymes. Transcription factors SRY, c‐FOS, and N‐Myc are the principal targets of the p38 pathway, Elk‐1 SAP1 and HLH2 of ERK, while FREAC‐4, ARNT and USF are shared. The results suggest a list of targets potentially useful in therapeutic interventions in cutaneous diseases and wound healing. J. Cell. Physiol. 215: 292–308, 2008. © 2008 Wiley‐Liss, Inc.
Radiosynthesis of (S)‐5‐methoxymethyl‐3‐[6‐(4,4,4‐trifluorobutoxy)benzo[d]isoxazol‐3‐yl] oxazolidin‐2‐[11C]one ([11C]SL25.1188), a novel radioligand for imaging monoamine oxidase‐B with PET
Authors: Bramoullé Yann , Puech Frédéric , Saba Wadad , Valette Heric , Bottlaender Michel , George Pascal , Dollé Frédéric
Published: February 2008

Within a novel series of 2‐oxazolidinones developed in the past by Sanofi‐Synthélabo, SL25.1188 ((S)‐5‐methoxymethyl‐3‐[6‐(4,4,4‐trifluorobutoxy)benzo[d]isoxazol‐3‐yl]oxazolidin‐2‐one), a compound that inhibits selectively and competitively MAO‐B in human and rat brain (Ki values of 2.9 and 8.5 nM for MAO‐B, respectively, and ED50 (rat): 0.6 mg/kg p.o.), was considered an appropriate candidate for imaging this enzyme with positron emission tomography. SL25.1188 was labelled with carbon‐11 (T1/2: 20.38 min) in one chemical step using the following process: (i) reaction of [11C]phosgene with the corresponding ring‐opened precursor (1.2–2.5 mg) at 100°C for 2 min in dichloromethane (0.5 mL) followed by (ii) concentration to dryness of the reaction mixture and finally (iii) semi‐preparative HPLC purification on a Waters Symmetry® C18. A total of 300–500 MBq of [11C]SL25.1188 (>95% chemically and radiochemically pure) could be obtained within 30–32 min (Sep‐pak‐based formulation included) with specific radioactivities ranging from 50 to 70 GBq/µmol (3.5–7% decay‐corrected radiochemical yield, based on starting [11C]CH4). Copyright © 2008 John Wiley & Sons, Ltd.
Real time analysis of the RNAI–RNAII–Rop complex by surface plasmon resonance: from a decaying surface to a standard kinetic analysis
Authors: Di Primo Carmelo
Published: February 2008

RNA loop–loop complexes are motifs that regulate biological functions in both prokaryotic and eukaryotic organisms. In E. coli, RNAI, an antisense RNA encoded by the ColE1 plasmid, regulates the plasmid replication by recognizing through loop–loop interactions RNAII, the RNA primer that binds to the plasmidic DNA to initiate the replication. Rop, a plasmid‐encoded homodimeric protein interacts with this transient RNAI–RNAII kissing complex. A surface plasmon resonance (SPR)‐based biosensor was used to investigate this protein‐nucleic acid ternary complex, at 5°C, in experimental conditions such as the protein binds either to the loop–loop complex while it dissociates or to a saturated stable RNAI–RNAII surface. The results show that RNAI hairpin dissociates from the RNAII surface 110 times slower in the presence of Rop than in its absence. Rop binds to RNAI–RNAII with an on‐rate of 3.6 × 106 M−1 s−1 and an off‐rate of 0.11 s−1, resulting in a binding equilibrium constant equal to 31 nM. A Scatchard‐plot analysis of the interaction monitored by SPR confirms a 1:1 complex of Rop and RNAI–RNAII as observed for non‐natural Rop–loop–loop complexes. Copyright © 2008 John Wiley & Sons, Ltd.
Mitochondrial displacements in response to nanomechanical forces
Authors: Silberberg Yaron R. , Pelling Andrew E. , Yakubov Gleb E. , Crum William R. , Hawkes David J. , Horton Mike A.
Published: February 2008

Mechanical stress affects and regulates many aspects of the cell, including morphology, growth, differentiation, gene expression and apoptosis. In this study we show how mechanical stress perturbs the intracellular structures of the cell and induces mechanical responses. In order to correlate mechanical perturbations to cellular responses, we used a combined fluorescence‐atomic force microscope (AFM) to produce well defined nanomechanical perturbations of 10 nN while simultaneously tracking the real‐time motion of fluorescently labelled mitochondria in live cells. The spatial displacement of the organelles in response to applied loads demonstrates the highly dynamic mechanical response of mitochondria in fibroblast cells. The average displacement of all mitochondrial structures analysed showed an increase of ∼40%, post‐perturbation (∼160 nm in comparison to basal displacements of ∼110 nm). These results show that local forces can produce organelle displacements at locations far from the initial point of contact (up to ∼40 µm). In order to examine the role of the cytoskeleton in force transmission and its effect on mitochondrial displacements, both the actin and microtubule cytoskeleton were disrupted using Cytochalasin D and Nocodazole, respectively. Our results show that there is no significant change in mitochondrial displacement following indentation after such treatments. These results demonstrate the role of the cytoskeleton in force transmission through the cell and on mitochondrial displacements. In addition, it is suggested that care must be taken when performing mechanical experiments on living cells with the AFM, as these local mechanical perturbations may have significant structural and even biochemical effects on the cell. Copyright © 2008 John Wiley & Sons, Ltd.