bluuebunny/crossref_metadata_2025 huggingface dataset:
Nucleophilic Ring‐Opening of Azetidinium Ions: Insights into Regioselectivity
Authors: Couty François , David Olivier , Durrat François , Evano Gwilherm , Lakhdar Sami , Marrot Jérome , Vargas‐Sanchez Monica
Published: June 2006

Enantiopure azetidinium salts presenting various and representative substitution patterns at C‐2, C‐3 and C‐4 have been prepared by alkylation of the corresponding azetidine with methyl trifluoromethanesulfonate. These compounds were treated with an array of nitrogen (azide anion or benzylamine) and oxygen (acetate anion or alkoxides) nucleophiles which provided interesting insights into the regioselectivity of the ring‐opening process. Nucleophilic opening occurred in most cases regioselectively at C‐4 with azetidinium ions possessing no substituent at this position. On the other hand, highly regioselective opening at C‐2 occurred with trisubstituted azetidinium ions bearing a methyl group at C‐4. Experimental selectivities together with DFT calculations have allowed a better understanding of the parameters governing the regioselectivities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
MALDI‐TOF/TOF de novo sequence analysis of 2‐D PAGE‐separated proteins from Halorhodospira halophila, a bacterium with unsequenced genome
Authors: Samyn Bart , Sergeant Kjell , Memmi Samy , Debyser Griet , Devreese Bart , Van Beeumen Jozef
Published: June 2006

Because protein identifications rely on matches with sequence databases, high‐throughput proteomics is currently largely restricted to those species for which comprehensive sequence databases are available. The identification of proteins derived from organisms with unsequenced genomes mainly depends on homology searching. Here, we report the use of a simplified, gel‐based, chemical derivatization strategy for de novo sequence analysis using a MALDI‐TOF/TOF mass spectrometer. This approach allows the determination of de novo peptide sequences of up to 20 amino acid residues in length. The protocol was applied on a proteomic study of 2‐D PAGE‐separated proteins from Halorhodospira halophila, an extremophilic eubacterium with yet unsequenced genome. Using three different homology‐based search algorithms, we were able to identify more than 30 proteins from this organism using subpicomole quantities of protein.
Proteomic analysis of cartilage‐ and bone‐associated samples
Authors: Lammi Mikko J. , Häyrinen Jukka , Mahonen Anitta
Published: June 2006

The skeleton of the human body is built of cartilage and bone, which are tissues that contain extensive amounts of extracellular matrix (ECM). In bone, inorganic mineral hydroxyapatite forms 50–70% of the whole weight of the tissue. Although the organic matrix of bone consists of numerous proteins, 90% of it is composed of type I collagen. In cartilage, ECM forms a major fraction of the tissue, type II collagen and aggrecans being the most abundant macromolecules. It is obvious that the high content of ECM components causes analytical problems in the proteomic analysis of cartilage and bone, analogous to those in the analysis of low‐abundance proteins present in serum. The massive contents of carbohydrates present in cartilage proteoglycans, and hydroxyapatite in bone, further complicate the situation. However, the development of proteomic tools makes them more and more tempting also for research of musculoskeletal tissues. Application of proteomic techniques to the research of chondrocytes, osteoblasts, osteocytes, and osteoclasts in cell cultures can immediately benefit from the present knowledge. Here we make an overview to previous proteomic research of cartilage‐ and bone‐associated samples and evaluate the future prospects of applying proteomic techniques to investigate key events, such as cellular signal transduction, in cartilage‐ and bone‐derived cells.
The Science of “Fingerprinting” Bees
Authors: Steinhage Volker , Schröder Stefan , Roth Volker , Cremers Armin B. , Drescher Wilhelm , Wittmann Dieter
Published: June 2006

The ABIS system allows the rapid and accurate identification of bee species. This process is based on automatic image analysis of the bee's wings and enables the development of new, computer‐aided methods to identify the bee species
Service and Performance
Authors: Schneider Christoph
Published: June 2006

The DFG promotes “all branches of science and the humanities”. This means that its Head Office is obliged to adhere to the rules of fair competition between the disciplines and to select the projects it funds on the basis of quality
The Turbulent Birth of a Star
Authors: Jappsen Anne‐Katharina , Schmeja Stefan , Klessen Ralf Stephan
Published: June 2006

The birth of a star is a dramatic process, about which there are many unanswered questions for astrophysicists. Researchers are now using computer simulations to shed light on the mechanisms which cause the gas in the Milky Way to form a star such as our own sun
Forests in the Clouds
Authors: Dohrenbusch Achim , Häger Achim
Published: June 2006

The montane rain forest in the tropical regions of the Earth provide living space for a fascinating plant world. As the example of Costa Rica shows, climatic factors have a major effect on both the flora and the ecosystem as a whole
Life at Lofty Heights
Authors: Schulze Christian H. , Fiedler Konrad
Published: June 2006

Studies of moths in Borneo provide new clues to understanding the diversity of tropical species and in assessing the consequences of deforestation
A joint model for the term structure of interest rates and the macroeconomy
Authors: Dewachter Hans , Lyrio Marco , Maes Konstantijn
Published: June 2006

We present and estimate a continuous time term structure model that incorporates observable macroeconomic variables and latent variables with a clear macroeconomic interpretation. Our model is able to accurately describe the joint dynamics for US macroeconomic variables and the yield curve. However, the observable variables do not explain the long end of the term structure. Central tendencies of these macroeconomic variables do a much better job in this respect. These unobservable factors also play an important role in the description of the interest rate policy rule. Both observable and non‐observable factors determine the risk premia and hence bond excess holding returns. Copyright © 2006 John Wiley & Sons, Ltd.
Estimating an economic model of crime using panel data from North Carolina
Authors: Baltagi Badi H.
Published: June 2006

This paper replicates the Cornwell and Trumbull (1994) estimation of a crime model using panel data on 90 counties in North Carolina over the period 1981–1987. While the Between and Within estimates are replicated, the fixed effects 2SLS as well as the 2SLS estimates are not. In fact, the fixed effects 2SLS estimates turn out to be insignificant for all important deterrent variables as well as legal opportunity variables. We argue that the usual Hausman test, based on the difference between fixed effects and random effects, may lead to misleading inference when endogenous variables of the conventional simultaneous equation type are among the regressors. We estimate the model using random effects 2SLS and perform a Hausman test based on the difference between fixed effects 2SLS and random effects 2SLS. We cannot reject the consistency of the random effects 2SLS estimator and this estimator yields plausible and significant estimates of the crime model. This result should be tempered by the legitimacy of the chosen instruments. Copyright © 2006 John Wiley & Sons, Ltd.
Modified aminosilane substrates to evaluate osteoblast attachment, growth, and gene expression in vitro
Authors: Siperko L.M. , Jacquet R. , Landis W.J.
Published: June 2006

Bone cell‐substrate interactions are important to understand in the design, selection, and surface modification of bone implants. To gain insight into such interactions, substrates designed with surface species approximating the physiological environment of bone matrix were studied. Osteoblasts (Ob) grown on three such surfaces were used to evaluate cell‐substrate effects on attachment, growth, and gene expression as compared with controls. Initial surface preparation consisted of coating glass slides with aminopropyltriethoxy silane (APTES), after which the coated slides were modified with collagen‐rich extracellular matrix components obtained from normally mineralizing avian tendon: the tripeptide arginine–glycine–aspartic acid (arg–gly–asp), or a precipitate formed from a metastable solution containing inorganic ions normally found in blood (simulated body fluid). Each of the modified substrates, as well as the nonmodified (APTES) control, provided distinctly different physical (evidenced by differences in rms roughness) and chemical surfaces for seeding primary osteoblasts obtained from 14‐day‐old normal embryonic chickens. Cell responses to each of the substrates were evaluated over a 21‐day period in terms of Ob growth and growth rate, alkaline phosphatase (ALP) activity, and gene expression of type I collagen (COL I), osteopontin (OPN), osteocalcin (OC), and bone sialoprotein (BSP). From these preliminary experiments, indications are that cell attachment and growth in this study possibly are independent processes, an assumption that compels the need for further studies. Collagen‐rich matrix‐modified substrates had a distinct advantage over others when cell growth rate, ALP activity, and gene expression were considered; cells on these substrates exhibited increased ALP activity and enhanced expression of BSP, OPN, and OC when compared with those of cells on APTES controls or other modified substrates. These results indicate that matrix‐modified substrates such as those used in this study provide favorable templates for tissue generation, suggesting their potential in the design of surfaces for bone implants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Characterization of DNA release from composites of oligo(poly(ethylene glycol) fumarate) and cationized gelatin microspheres in vitro
Authors: Kasper F. Kurtis , Jerkins Erin , Tanahashi Kazuhiro , Barry Michael A. , Tabata Yasuhiko , Mikos Antonios G.
Published: June 2006

This research investigates the release of plasmid DNA from novel hydrogel composites of oligo(poly(ethylene glycol) fumarate) (OPF) and cationized gelatin microspheres (CGMS), as well as the swelling and degradation of these materials in vitro. The release of total DNA and of double‐stranded DNA was measured fluorescently, and the swelling properties and polymer mass loss of the hydrogels were assessed. Further, the structural integrity of the released DNA was determined through electrophoresis. It was found that plasmid DNA can be released in a sustained fashion over the course of up to 49–140 days in vitro from hydrogels of OPF synthesized from poly(ethylene glycol) of nominal molecular weights of 10 kDa and 3 kDa, respectively, with the release kinetics depending upon the material composition and the method of DNA loading. Released DNA was predominately double‐stranded DNA (dsDNA) in structure and of the open‐circular conformation. The results suggest that DNA release from hydrogel composites of OPF and CGMS is dominated by the degradation of the OPF component of the gels. Electrophoresis results indicate that the released DNA retains suitable conformation for potential bioactivity over the course of at least 63 days of release. Thus, these studies demonstrate the potential of composites of OPF and CGMS in controlled gene delivery applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro homogeneous and heterogeneous degradation of poly(ϵ‐caprolactone/polyethylene glycol/L‐lactide): The absence of autocatalysis and the role of enzymes
Authors: Wang Zhaoxu , Wang Shenguo , Guidoin Robert , Marois Yves , Zhang Ze
Published: June 2006

This study investigated the in vitro degradation behavior of poly(ϵ‐caprolactone/polyethylene glycol/L‐lactide) (PCEL) in comparison with that of three other biodegradable polymers. Polymer membranes were incubated in pancreatin solution, Ringer's solution, and distilled water at 37°C for up to 20 weeks. Characterization involved measuring weight loss, observing the morphological changes by scanning electron microscopy (SEM), analyzing molecular weight using size exclusion chromatography (SEC), and studying the crystalline structure using differential scanning calorimetry (DSC). The hydrolysis in a simple aqueous solution experienced no autocatalysis, which was attributed to the high permeability of PCEL to water‐soluble degradation products. Similar degradation rates were recorded for the PCEL and poly(L,L‐lactide) (PLLA) test membranes. In the presence of pancreatin, the PCEL membrane experienced rapid heterogeneous surface erosion likely caused by the selective loss of its surface PEG components under enzymatic action. Pancreatin also substantially increased the even physical resorption of the other test polymers by eliminating autocatalysis. This study demonstrated that autocatalysis commonly experienced by poly(α‐hydroxyl acid) can be reduced through chemical formulation or high enzyme activity. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Activation of ERK signaling upon alternative protease nexin‐1 internalization mediated by syndecan‐1
Authors: Li Xiaobiao , Herz Joachim , Monard Denis
Published: June 2006

Protease nexin‐1 (PN‐1), an inhibitor of serine proteases, contributes to tissue homeostasis and influences the behavior of some tumor cells. The internalization of PN‐1 protease complexes is considered to be mediated by the low‐density lipoprotein receptor related protein 1 (LRP1). In this study, both wild‐type and LRP1−/− mouse embryonic fibroblasts (MEF) were shown to internalize PN‐1. Receptor associated protein (RAP) interfered with PN‐1 uptake only in wild‐type MEF cells, indicating that another receptor mediates PN‐1 uptake in the absence of LRP1. In LRP1−/− MEF cells, inhibitor sensitivity and kinetic values (t1/2 at 45 min) of PN‐1 uptake showed a similarity to syndecan‐1‐mediated endocytosis. In these cells, PN‐1 uptake was increased by overexpression of full‐length syndecan‐1 and decreased by RNA interference targeting this proteoglycan. Most important, in contrast to PKA activation known to be triggered by LRP1‐mediated internalization, our study shows that syndecan‐1‐mediated internalization of PN‐1 stimulated the Ras‐ERK signaling pathway. J. Cell. Biochem. 99: 936–951, 2006. © 2006 Wiley‐Liss, Inc.
Differential expression of tropomyosin during segmental heart development in Mexican axolotl
Authors: Zajdel Robert W. , McLean Matthew D. , Denz Christopher R. , Dube Syamalima , Thurston Harold L. , Poiesz Bernard J. , Dube Dipak K.
Published: June 2006

The Mexican axolotl, Ambystoma mexicanum, serves as an intriguing model to investigate myofibril organization and heart development in vertebrates. The axolotl has a homozygous recessive cardiac lethal gene “c” which causes a failure of ventricular myofibril formation and contraction. However, the conus of the heart beats, and has organized myofibrils. Tropomyosin (TM), an essential component of the thin filament, has three known striated muscle isoforms (TPM1α, TPM1κ, and TPM4α) in axolotl hearts. However, it is not known whether there are differential expression patterns of these tropomyosin isoforms in various segments of the heart. Also, it is not understood whether these isoforms contribute to myofibril formation in a segment‐specific manner. In this study, we have utilized anti‐sense oligonucleotides to separately knockdown post‐transcriptional expression of TPM1α and TPM4α. We then evaluated the organization of myofibrils in the conus and ventricle of normal and cardiac mutant hearts using immunohistochemical techniques. We determined that the TPM1α isoform, a product of the TPM1 gene, was essential for myofibrillogenesis in the conus, whereas TPM4α, the striated muscle isoform of the TPM4 gene, was essential for myofibrillogenesis in the ventricle. Our results support the segmental theory of vertebrate heart development. J. Cell. Biochem. 99: 952–965, 2006. © 2006 Wiley‐Liss, Inc.
Growth of choroid plexus epithelium vesicles in vitro depends on secretory activity
Authors: Swetloff Adam , Greenwood Sarah , Wade Angela M. , Ferretti Patrizia
Published: June 2006

Although a number of models have been used to study choroid plexus epithelium (CPe) function, analysis in physiological conditions of this polarised epithelium which produces the majority of the cerebrospinal fluid (CSF) and is one of the key barriers between blood and CSF in the brain remains challenging. As CPe cells form polarised CPe vesicles when cultured in Matrigel, we have assessed their behaviour and potential use for pharmacological studies. Like CPe cells in vivo, CPe vesicles express transthyretin, E2f5, Fox‐j1 and p73, and contain tight junctions, as indicated by ZO‐1 expression and electron microscopy analysis. Time‐lapse microscopy shows that CPe cells plated in Matrigel are highly migratory and rapidly form homotypic cell aggregates, which then reorganise to form vesicles whose size increases linearly over time. Neither aggregate nor vesicle size is affected by AraC treatment, though this inhibitor significantly reduces proliferation in CPe monolayers. Increase in size of vesicles, which have reached a growth plateau is observed following addition of fluorescently‐labelled CPe cells, which become incorporated into the vesicle walls. Significantly, treatment with secretion inhibitors blocks vesicle formation and their expansion. These results show that secretion, rather than cell division, controls vesicle growth, consistent with low levels of proliferation and thinning of the CPe observed both in growing vesicles and during CPe development. Therefore, changes in vesicle size can be used to evaluate the effect of putative molecules involved in the regulation of secretion. J. Cell. Physiol. 208: 549–555, 2006. © 2006 Wiley‐Liss, Inc.
Re‐evaluation of the distinction between type I and type II cells: The necessary role of the mitochondria in both the extrinsic and intrinsic signaling pathways upon fas receptor activation
Authors: Tafani Marco , Karpinich Natalie O. , Serroni Ada , Russo Matteo A. , Farber John L.
Published: June 2006

Cyclosporin A (CyA) and bongkrekic acid (BK) prevented Fas‐induced apoptosis in two type I cell lines (H9 and SKW6.4) and two type II cell lines (Jurkat and CEM). CyA and BK inhibited the release of cytochrome c in all four cell lines. In type I cells and in CEM cells, CyA and BK did not prevent the translocation of Bax to the mitochondria. In these same cells, full‐length Bid decreased in the mitochondria and cytosol. The cleavage product of Bid, tBid, appeared in the cytosol and to a lesser extent in the mitochondria. In Jurkat cells, Bid also decreased in the cytosol, but increased in the mitochondria. Similar to the other cells, tBid appeared in the mitochondria and cytosol. In the type I H9 and SKW6.4 cells and type II Jurkat cells, the caspase‐8 inhibitor Z‐Ile‐Glu(OMe)‐Thr‐Asp(OMe)‐CH2F (IETD) prevented the cell killing. In the type I cells, IETD prevented the translocation of Bax, the degradation of Bid and the accumulation of tBid. By contrast, IETD only marginally protected the type II CEM cells. In these cells in the presence of IETD, Bax translocated to the mitochondria, in the absence of any degradation of Bid or accumulation of tBid. In the type I H9 cells, IETD produced a depletion of ATP, an effect that did not occur in the type II CEM cells. It is concluded that in type I cells the extrinsic signaling pathway is mitochondrial dependent to the same extent as is the intrinsic pathway in type II cells. J. Cell. Physiol. 208: 556–565, 2006. © 2006 Wiley‐Liss, Inc.
Regulation of phosphatidylinositol 3‐kinase (PI3K)/Akt and nuclear factor‐kappa B signaling pathways in dystrophin‐deficient skeletal muscle in response to mechanical stretch
Authors: Dogra Charu , Changotra Harish , Wergedal Jon E. , Kumar Ashok
Published: June 2006

Phosphatidylinositol 3‐kinase (PI3K)/Akt and nuclear factor‐kappa B (NF‐κB) signaling pathways play a critical role in mediating survival signals. In this study we have investigated how loss of dystrophin (the primary cause of Duchenne muscular dystrophy) modulates the activation of PI3K/Akt and NF‐κB signaling pathways in skeletal muscle in response to mechanical stimulation. Activation of Akt was significantly higher in diaphragm muscle from dystrophin‐deficient mdx mice compared to normal mice at both prenecrotic and necrotic states. Higher activation of Akt was also observed in cultured dystrophin‐deficient primary myotubes differentiated in vitro. Application of passive mechanical stretch ex vivo synergistically increased the activation of Akt in diaphragm of mdx mice. Stretch‐induced activation of PDK‐1 and PI3K were also higher in diaphragm of mdx mice compared to normal mice. Pretreatment of diaphragm with PI3K inhibitor LY294002 blocked the activation of Akt in normal and mdx mice. Higher activation of Akt was associated with increased phosphorylation of its downstream targets glycogen synthase kinase 3β (GSK3β), FKHR, and mammalian target of rapamycin (mTOR). Treatment of diaphragm muscle with LY294002 inhibited the stretch‐induced activation of IkappaB (IκB) kinase (IKK) and NF‐κB transcription factor in normal and mdx mice. Mechanical stretch also reduced the interaction of HDAC1 with RelA subunit of NF‐κB in diaphragm muscle. Finally, cellular levels of Bcl‐2, cIAP1, and integrin β1 and activation of integrin linked kinase were higher in diaphragm muscle of mdx mice compared to normal mice. Taken together, our data suggest that loss of dystrophin and/or mechanical stretch results in the up‐regulation of PI3K/Akt and NF‐κB signaling pathways in skeletal muscle. J. Cell. Physiol. 208: 575–585, 2006. © 2006 Wiley‐Liss, Inc.
ATR dependent activation of Chk2
Authors: Wang Xiao Qi , Redpath J. Leslie , Fan Sheung Tat , Stanbridge Eric J.
Published: June 2006

ATM and ATR are essential regulators of DNA damage checkpoints in mammalian cells through their respective effectors, Chk2 and Chk1. Cross regulation of the ATM‐Chk2 and ATR‐Chk1 pathways is very limited, although ATM and ATR show overlapping function in a partnership and time‐dependent manner. In this study, we report that Chk2 is a substrate of ATR in response to ionizing and ultraviolet radiation. ATR activation induced by ionizing radiation (IR) is weak in ATM+/+ cells. However, when ATM is inhibited by caffeine, ATR activation is markedly enhanced. Total Chk2 and Chk2 Thr68 are also hyperphosphorylated in the presence of caffeine. Both ATM+/+ and ATM−/− cells display normal ATR activation in response to UV radiation‐induced DNA damage, which is caffeine sensitive. In two lines of ATM‐deficient, as well as in an ATM siRNA silencing cell line, ATR is activated when the cells are exposed to IR and is able to phosphorylate Chk2 in vitro. These observations suggest that ATR is one of the kinases that is likely involved in phosphorylation of Chk2 in response to IR when ATM is deficient. J. Cell. Physiol. 208: 613–619, 2006. © 2006 Wiley‐Liss, Inc.
Nucleotide receptors stimulation by extracellular ATP controls Hsp90 expression through APE1/Ref‐1 in thyroid cancer cells: A novel tumorigenic pathway
Authors: Pines Alex , Bivi Nicoletta , Vascotto Carlo , Romanello Milena , D'Ambrosio Chiara , Scaloni Andrea , Damante Giuseppe , Morisi Roberta , Filetti Sebastiano , Ferretti Elisabetta , Quadrifoglio Franco , Tell Gianluca
Published: June 2006

Nucleotide receptors signaling affects cell proliferation, with possible implications on tumorigenic processes. However, molecular targets and action mechanisms of the extracellular nucleotides are still poorly elucidated. We have previously shown in ARO cells that APE1/Ref‐1, a transcriptional coactivator responsible for the maintenance of the cellular proliferative rate, is functionally controlled by P2‐mediated signaling. Here, we demonstrate that extracellular ATP has a mitogenic effect on ARO cells, increasing ERK phosphorylation, AP1 activation, and cyclin D1 expression. Using the ATP/ADPase apyrase and the P2 receptor antagonist suramin, we show that the extracellular ATP, physiologically released by ARO cells, exerts mitogenic effects. A differential proteomic approach was used to identify molecular events associated with the ATP‐induced cell proliferation. Among other proteins, Hsp90 was found upregulated upon ATP stimulation. Pretreatment with suramin completely blocked the ATP‐induced Hsp90 activation, confirming the involvement of cell‐surface P2 nucleotide receptors in the ATP‐mediated activation of ARO cells. Treatment of proliferating ARO cells with suramin and apyrase significantly reduced the intracellular levels of Hsp90, suggesting an autocrine/paracrine mechanism of control on Hsp90 expression by extracellular ATP. The influence of Hsp90 on ATP‐induced cell proliferation was also demonstrated by its specific inhibition with 17‐AAG. The molecular pathway by which ATP stimulates cell proliferation was further investigated by siRNA strategies showing that Hsp90 is a target of APE1/Ref‐1 functional activation. Stimulation of ARO cells with specific nucleotide receptors agonists evidenced a major involvement of P2Y1and P2Y2receptors in controlling the Hsp90 activation. Accordingly, these two receptors resulted significantly upregulated in sample biopsies from different thyroid tumors. J. Cell. Physiol. 209: 44–55, 2006. © 2006 Wiley‐Liss, Inc.
Sexual Health After Orthotopic Liver Transplantation
Authors: Ho Jin K. , Ko Hin Hin , Schaeffer David F. , Erb Siegfried R. , Wong Cherise , Buczkowski Andrzej K. , Scudamore Charles H. , Yoshida Eric M.
Published: June 2006

Many studies have reported improved health-related quality of life outcomes after orthotopic liver transplantation; however, specific research regarding sexual health in liver transplant recipients is limited. We surveyed liver transplant recipients to determine the prevalence of sexual dysfunction. Of the 320 adult liver transplant recipients surveyed by mailed questionnaire, 150 responded (42%). The median age was 54 years. A total of 62% of respondents were male, and 93% were at least 1 year after transplantation. Thirty-six respondents (24%) reported sexual dysfunction before transplantation; this persisted in 22 patients (15%) after transplantation. A total of 48 respondents (32%) reported de novo sexual dysfunction after transplantation. After transplantation, 23% of male and 26% of female respondents reported decreased libido, and 33% of men and 26% of women reported having difficulty reaching orgasm with intercourse. A total of 42% of respondents felt that immunosuppressive medication was the main contributing factor to their sexual problems: 33% and 35% of respondents receiving tacrolimus or cyclosporine monotherapy, respectively, experienced some degree of sexual problems after transplantation. Despite the reported sexual problems, 59% of respondents were “moderately” to “very satisfied” with their sexual relationships after transplantation. Nineteen percent of the respondents used sildenafil to improve their sexual function, and 65% of these reported benefit. In conclusion, sexual problem after orthotopic liver transplantation is a common but poorly studied problem. Although this single-center study has shed some light on the relationship between liver transplantation and sexual health, further prospective studies, involving larger study population and validated instruments, will be needed to better evaluate the influence of liver transplantation on recipients' sexual health.
Liver Transpl 12:1478-1484, 2006.

© 2006 AASLD.
Suppression of Cell and Platelet Adhesion to Star‐Shaped 8‐Armed Poly(ethylene glycol)‐Poly(L‐lactide) Block Copolymer Films
Authors: Nagahama Koji , Ohya Yuichi , Ouchi Tatsuro
Published: June 2006

Summary: To explore the potential of a star‐shaped 8‐armed poly(ethylene glycol)35K‐block‐poly(L‐lactide)37K (8‐armed PEG35K‐b‐PLLA37K: $\overline M _{\rm n}$ of PEG = 35 000, $\overline M _{\rm n}$ of PLLA = 37 000) film as a novel bioabsorbable adhesion‐prevention membrane, the water structure, surface contact angle, protein adsorption, and cell and platelet anti‐adhesion properties of such a hydrated film are investigated. Based on the results, it is found that the 8‐armed PEG35K‐b‐PLLA37K film exhibits a biologically inert surface, which is the result of a large number of PEG chains and a free water layer on the film surface. This leads to a reduction in protein absorption and cell and platelet adhesion onto the film surface. This implies that the star‐shaped 8‐armed PEG35K‐b‐PLLA37K film can be utilized as a novel bioabsorbable adhesion‐prevention membrane.

A schematic presentation of the protein adsorption, platelet adhesion, and cell attachment phenomena for the 8‐armed PEG‐b‐PLLA films.

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A schematic presentation of the protein adsorption, platelet adhesion, and cell attachment phenomena for the 8‐armed PEG‐b‐PLLA films.
Preparation of New Bioactive Hybrid Bone Cements Containing Bis‐GMA Derivatives as a Prepolymer
Authors: Park Bang‐Ju , Park Kwideok , Ahn Kwang‐Duk , Chin Yong‐Ok , Han Dong Keun
Published: June 2006

Summary: Novel organic‐inorganic hybrid bioactive bone cements containing bisphenol‐A‐glycidyl methacrylate (Bis‐GMA) derivatives and a bioactive inorganic filler were prepared for orthopedic applications. The Bis‐GMA derivatives, such as 3MA and a 3MA mixture (3MA mix), were synthesized by blocking one or two of the hydroxyl groups of the Bis‐GMA so as to use it as a prepolymer. Four organic prepolymers, such as Bis‐GMA, 3MA, 3MA 50 and 3MA mix, and an inorganic filler, AW‐GC, were used for the preparation of the bioactive bone cements and their characteristics were evaluated. As compared with the Bis‐GMA control, the new bioactive bone cements containing the Bis‐GMA derivatives exhibited appropriate curing times, low polymerization shrinkage, low water absorption and solubility as well as high mechanical properties. In particular, the bioactive bone cement containing 3MA mix and AW‐GC had higher bending and compressive strengths than the Bis‐GMA one.

Curing time and polymerization shrinkage on various prepolymers of bioactive bone cements.

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Curing time and polymerization shrinkage on various prepolymers of bioactive bone cements.
Deuterium isotope effect on 13C chemical shifts of tetrabutylammonium salts of Schiff bases amino acids
Authors: Rozwadowski Z.
Published: June 2006

Deuterium isotope effects on 13C chemical shift of tetrabutylammonium salts of Schiff bases, derivatives of amino acids (glycine, L‐alanine, L‐phenylalanine, L‐valine, L‐leucine, L‐isoleucine and L‐methionine) and various ortho‐hydroxyaldehydes in CDCl3 have been measured. The results have shown that the tetrabutylammonium salts of the Schiff bases amino acids, being derivatives of 2‐hydroxynaphthaldehyde and 3,5‐dibromosalicylaldehyde, exist in the NH‐form, while in the derivatives of salicylaldehyde and 5‐bromosalicylaldehyde a proton transfer takes place. The interactions between COO− and NH groups stabilize the proton‐transferred form through a bifurcated intramolecular hydrogen bond. Copyright © 2006 John Wiley & Sons, Ltd.
An analysis of the exclusion criteria used in observational pharmacoepidemiological studies
Authors: Perrio Michael , Waller Patrick C. , Shakir Saad A. W.
Published: June 2006

Purpose

The application of exclusion criteria in pharmacoepidemiological studies could have a major impact on the findings but there appears to have been no previous research to examine the types of exclusion criteria applied.

Methods

We searched the literature and identified 10 senior pharmacoepidemiologists who had published five or more relevant papers between 1999 and 2004. All their published drug safety studies during this period were reviewed. A classification system was developed to categorise the exclusion criteria, with 5 categories and 11 sub‐categories. The categories were: (1) data quality and validation, (2) disease‐related, (3) exposure‐related, (4) patient characteristics and (5) miscellaneous reasons. Within each sub‐category, only the first exclusion criterion identified for that study was counted.

Results

We identified 200 studies, from which a total of 752 exclusion criteria sub‐categories had been applied (mean 3.8 per study; between‐author range of means 2.8–5.1). At the category level, exclusion criteria relating to data quality and validation were the most commonly applied (87% of publications), followed by patient characteristics (75%), disease‐related (69%), exposure‐related (38%) and miscellaneous (3%). The main categories for which research practice appeared to differ were those relating to diseases and exposures. The application of sub‐category ‘risk factors and alternative causes’ varied between authors from 0% to 81% of studies, and for the sub‐category ‘medication of interest’ it varied from 5% to 93%.

Conclusions

There are important differences between investigators in the application of exclusion criteria in pharmacoepidemiological studies. It is likely that a substantial part of the observed variation reflects different research practices of investigators. Copyright © 2006 John Wiley & Sons, Ltd.
From BIS/BAS to the big five
Authors: Smits Dirk J. M. , Boeck P. D.
Published: June 2006

Gray (1987) proposed two systems that underlie much of our behaviour and personality. One system relates to avoidance or withdrawal behaviour, called the Behavioural Inhibition System (BIS), whereas the other system relates to approach behaviour, called the Behavioural Approach System (BAS). In two samples, it was investigated whether individual differences in surface of personality as described by the Big Five can be explained by BIS/BAS. Neuroticism and Extraversion could be explained well by BIS/BAS, but also for Agreeableness and Conscientiousness consistent findings were obtained. Copyright © 2006 John Wiley & Sons, Ltd.
The synthesis, characterization, and crystal structures of poly(2,6‐naphthalenebenzobisoxazole) and poly(1,5‐naphthalenebenzobisoxazole)
Authors: Park Soo‐Young , Moon Sang‐Cheol , Venkatasubramanian N. , Dang Thuy D. , Lee Jar‐Wha , Farmer B. L.
Published: June 2006

The rigid‐rod polymers, poly(2,6‐naphthalenebenzobisoxazole) (Naph‐2,6‐PBO) and poly(1,5‐naphthalenebenzobisoxazole) (Naph‐1,5‐PBO) were synthesized by high temperature polycondensation of isomeric naphthalene dicarboxylic acids with 4,6‐diaminoresorcinol dihydrochloride in polyphosphoric acid. Expectedly, these polymers were found to have high thermal as well as thermooxidative stabilities, similar to what has been reported for other polymers of this class. The chain conformations of Naph‐2,6‐PBO and Naph‐1,5‐PBO were trans and the crystal structures of Naph‐2,6‐PBO and Naph‐1,5‐PBO had the three‐dimensional order, although the axial disorder existed for both Naph‐2,6‐PBO and Naph‐1,5‐PBO. Naph‐2,6‐PBO exhibited a more pronounced axial disorder than Naph‐1,5‐PBO because of its more linear shape. The repeat unit distance for Naph‐2,6‐PBO (14.15 Å) was found to be larger compared with that of Naph‐1,5‐PBO (12.45 Å) because of the more kinked structure of the latter. The extents of staggering between the adjacent chains in the ac projection of the crystal structure were 0.25c and 0.23c for Naph‐2,6‐PBO and Naph‐1,5‐PBO, respectively. Naph‐1,5‐PBO has a more kinked and twisted chain structure relative to Naph‐2,6‐PBO. The kinked and twisted chain structure of Naph‐1,5‐PBO in the crystal seems to prevent slippage between adjacent chains in the crystal structure. The more perfect crystal structure of Naph‐1,5‐PBO may be due to this difficulty in the occurrence of the slippage. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1948–1957, 2006
Computational model for the IGF‐II/IGF2r complex that is predictive of mutational and surface plasmon resonance data
Authors: Roche Philippe , Brown James , Denley Adam , Forbes Briony E. , Wallace John C. , Jones E. Yvonne , Esnouf Robert M.
Published: June 2006

Insulin‐like growth factors (IGFs) are key regulators of cell proliferation, differentiation, and transformation, and are thus pivotal in cancer, especially breast, prostate, and colon neoplasm. Their potent mitogenic and anti‐apoptotic actions depend primarily on their availability to bind to the signaling IGF cell surface receptors. One mechanism by which IGF‐II availability is thought to be modulated is by binding to the nonsignaling IGF‐II receptor (IGF2R). This binding is essentially mediated by domain 11 in the multidomain IGF2R extracellular region. The crystal structure of domain 11 of the human IGF‐II receptor (IGF2R‐d11) has identified a putative IGF‐II binding site, and a nuclear magnetic resonance (NMR) solution structure for the IGF‐II ligand has also been characterized. These structures have now been used to model in silico the protein–protein interaction between IGF‐II and IGF2R‐d11 using the program 3D‐Dock. Because the IGF‐II data comprise an ensemble of 20 structures, all of which satisfy the NMR constraints, the docking procedure was applied to each member of the ensemble. Only those models in which residue Ile1572 of IGF2R‐d11, known to be essential for the binding of IGF‐II, was at the interface were considered further. These plausible complexes were then critically assessed using an array of analysis techniques including consideration of additional mutagenesis data. One model was strongly supported by these analyses and is discussed here in detail. Furthermore, we demonstrate in vitro experimental support for this model by studying the binding of chimeras of IGF‐I and IGF‐II to IGF2R fragments. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Trigonal splitting and local structure of Co2+ cluster in zinc oxide metaborate crystal
Authors: Maolu Du , Jian Ma , Qinghan Chen
Published: June 2006

Zn4O(BO2)6:Co2+ crystal is suitable for applications as a saturable absorber for 1.54 µm lasers. In this crystal, the Co2+ ion substitutes for the Zn2+ ion and the Co2+ cluster is the active center of saturable absorption. The Co–O tetrahedron in Zn4O(BO2)6:Co2+ crystal exhibits small distortions from the Zn–O tetrahedron in the host crystal. It is difficult to determine the structure of the Co–O tetrahedron from X‐ray experiments. From the d–d transition of the trigonal Co2+ cluster in Zn4O(BO2)6:Co2+ crystal, which depends on the local structure of Co–O tetrahedron, we determine the structural parameters as: the Co–OI bond length R 1 ≈ 0.1987 nm, the Co–OII bond length R 2 ≈ 0.192 nm, and the OI–Co–OII angle Θ2 ≈ 112°. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin transport through a ZnSe‐based diluted magnetic semiconductor resonant tunneling structure in the presence of electric and magnetic fields
Authors: Papp G. , Borza S. , Peeters F. M.
Published: June 2006

Spin‐dependent tunneling of electrons in asymmetric double quantum wells and barriers composed of different sequences of diluted magnetic and nonmagnetic well and barrier materials are investigated theoretically for ZnSe‐based semiconductor heterostructures in the presence of parallel magnetic and electric fields. In the studied systems the transmission of electrons and the degree of spin polarization depends on the strength of the magnetic (due to the s–d exchange‐enhanced spin splitting) and electric fields and on the direction of the applied bias, resulting in a highly spin polarized gas. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite element analysis of vent/hand hole designs for corrugated fibreboard boxes
Authors: Han Jongkoo , Park Jong Min
Published: June 2006

Corrugated fibreboard is an economical and efficient material for fabricating shipping containers that are widely used for the distribution, transportation and storage of goods. Corrugated fibreboard is usually considered to be an orthotropic material because the principal fibre directions, machine direction (MD) and cross‐machine direction (CD), are identical to the fibres in paperboard, which has apparent directional property differences. The purpose of this study is to investigate the principal design parameters of ventilation holes and hand holes in the faces of the shipping container, (corrugated fibreboard boxes), using finite element analysis (FEA). Various designs of ventilation holes were studied with respect to stress distribution and stress level. It was found that the appropriate pattern and location of the ventilation holes were vertical oblong‐shaped and symmetrically positioned within a certain extent of distance to the right and left from the centre of the front and rear faces of the boxes. On the other hand, the appropriate location and pattern of the hand holes were a short distance from the centre to the top of the boxes on both side faces. The appropriate pattern was a modified shape, such as the radius of curvature of both sides in horizontal oblong. The pattern and location of both the ventilation holes and the hand holes determined by the FEA simulation generally agreed well with laboratory experimental results. The decrease in compression strength of the box could be minimized with identical area of the ventilation holes if the length of the major axis of the ventilation hole is less than 1/4 of the depth of the box and the ratio of the minor axis to the major axis is 1/3.5–1/2.5, provided that even‐numbered holes are located symmetrically. Copyright © 2006 John Wiley & son, Ltd.
Commentary onBecoming a Daughter: Trauma is a Powerful Teacher
Authors: Veach Patricia McCarthy
Published: June 2006

Personal life crises profoundly impact genetic counselor practice. In this commentary, themes from Matloff's (in press) article,Becoming a Daughterare highlighted and expanded upon. These themes include: personal impact of a life crisis, and professional impact vis a vis empathy countertransference, self‐disclosure, nondirectiveness, and self‐confidence. Strategies that help genetic counselors manage personal life crises within their clinical practice and also promote their professional development are emphasized, including normalization of life crises, self‐reflection, boundary‐setting, and use of peer supervision and consultation.
Characterization of two populations of mesenchymal progenitor cells in umbilical cord blood
Authors: Chang Yu‐Jen , Tseng Ching‐Ping , Hsu Lee‐Feng , Hsieh Tzu‐Bou , Hwang Shiaw‐Min
Published: June 2006

Umbilical cord blood (UCB) is a valuable source for hematopoietic progenitor cell therapy. Moreover, it contains another subset of non‐hematopoietic population referred to as mesenchymal progenitor cells (MPCs), which can be ex vivo expanded and differentiated into osteoblasts, chondrocytes and adipocytes. In this study, we successfully isolated the clonogenic MPCs from UCB by limiting dilution method. These cells exhibited two different morphologic phenotypes, including flattened fibroblasts (majority) and spindle‐shaped fibroblasts (minority). Both types of MPCs shared similar cell surface markers except CD90 and had similar osteogenic and chondrogenic potentials. However, the spindle‐shaped clones possessed the positive CD90 expression and showed a greater tendency in adipogenesis, while the flattened clones were CD90 negative cells and showed a lower tendency in adipogenesis. The high number of flattened MPCs might be linked to the less sensitivity of UCB‐derived MPCs in adipogenic differentiation.
Coronary sinus thermography in idiopathic dilated cardiomyopathy: Correlation with systemic inflammation and left ventricular contractility
Authors: Toutouzas Konstantinos , Stougiannos Pavlos , Drakopoulou Maria , Mitropoulos John , Bosinakou Eirini , Markou Virginia , Latsios George , Karabelas Ioannis , Stefanadi Elli , Stefanadis Christodoulos
Published: June 2006

Background

Previous studies have demonstrated that patients with heart failure have increased myocardial heat production. Coronary sinus (CS) thermography is a new method for the evaluation of left ventricular heat production.

Aims

We investigated whether the CS blood temperature is increased in patients with idiopathic dilated cardiomyopathy (DCM) compared to a control group and whether the CS blood temperature correlates with ejection fraction and systemic inflammatory activation.

Methods and results

We included 25 patients with DCM and 22 healthy subjects. Temperature measurements were performed using a new thermography catheter. Temperature difference (ΔT) was defined as the difference between the CS and RA blood temperature. The CRP levels were also measured.

ΔT was significantly greater in patients with DCM compared to the controls (0.25±0.09 vs 0.14±0.07 °C, p<0.01). ΔT and EF were inversely correlated in patients with DCM (R=0.43). We categorized patients with DCM into two groups using a CRP cut‐off value of ≤1 mg/dL. ΔT in patients with high CRP was less (0.21±0.06 °C) compared to patients with low CRP (0.30±0.08 °C, p=0.01).

Conclusions

In patients with DCM increased heat production from the myocardium, as estimated from the coronary sinus blood temperature, was demonstrated, interestingly there was no correlation with systemic inflammatory activation.
Polo‐like kinase 1 regulates mitotic arrest after UV irradiation through dephosphorylation of p53 and inducing p53 degradation
Authors: Chen Jie , Dai Gu , Wang Yi-Qian , Wang Sheng , Pan Fei-Yan , Xue Bin , Zhao Dong-Hong , Li Chao-Jun
Published: June 2006

Ultraviolet (UV) irradiation can result in cell cycle arrest. The reactivation of Polo‐like kinase 1 (Plk1) is necessary for cell cycle reentry. But the mechanism of how Plk1 regulates p53 in UV‐induced mitotic arrest cells remained elusive. Here we find that UV treatment leads HEK293 cells to inverse changes of Plk1 and p53. Over‐expression of Plk1 rescue UV‐induced mitotic arrest cells by inhibiting p53 activation. Plk1 could also inhibit p53 phosphorylation at Ser15, thus facilitates its nuclear export and degradation. Further examination shows that Plk1, p53 and Cdc25C can form a large complex. Plk1 could bind to the sequence‐specific DNA‐binding domain of p53 and active Cdc25C by hyperphosphorylation. These results hypothesize that Plk1 and Cdc25C participate in recovery the mitotic arrest through binding to the different domain of p53. Cdc25C may first be actived by Plk1, and then its phosphatase activity makes p53 dephosphorylated at Ser15.
Oxidative stress markers and antioxidant levels in normal pregnancy and pre‐eclampsia
Authors: Sharma J.B. , Sharma Alpana , Bahadur Anupama , Vimala N. , Satyam Abhigyan , Mittal Suneeta
Published: June 2006

Objective: To compare the levels of 3 oxidative stress markers (glutathione peroxidase [GPX], superoxide dismutase [SOD], and malondialdehyde [MDA]) and 2 antioxidants (vitamin C and lycopene) in healthy and pre‐eclamptic pregnant women.

Methods: Circulating levels of GPX, SOD, MDA, vitamin C and lycopene were measured in 50 healthy pregnant women and 50 women with pre‐eclampsia (PE) (41 with mild PE and 9 with severe PE) attending the antenatal clinic or admitted to the maternity ward of the All‐India Institute of Medical Sciences, New Delhi, India.

Results: The levels of GPX, SOD and MDA were significantly higher in women with PE than in controls, and the increase was higher in women with severe PE (P < 0.001 using analysis of variance and the Kruskal Wallis test). The levels of vitamin C and lycopene were significantly lower in women with PE than in controls, with a greater decrease in women with severe PE.

Conclusion: Increased levels of oxidative stress markers and decreased levels of antioxidants in pre‐eclamptic women suggest that oxidative stress markers play a significant role in the pathophysiology of pre‐eclampsia, and that supplemental dietary antioxidants may have a beneficial role in the prevention of pre‐eclampsia in women at high‐risk for this condition.