bluuebunny/crossref_metadata_2025_split huggingface dataset:
Revision of collagen molecular structure
Authors: Okuyama Kenji , Xu Xiaozhen , Iguchi Makoto , Noguchi Keiichi 
Published: October 2005

AbstractBased on the fiber diffraction data from native collagen, Rich and Crick proposed the 10/3‐helical model with a 28.6 Å axial repeat in 1955 (Rich A.; Crick, F. H. C. Nature (Lond) 1955, 176, 915–916). We obtained the 7/2‐helical structure with a 20 Å axial repeat from the single crystal analysis of (Pro–Pro–Gly)10. Since the latter structure could explain fiber diffraction patterns from native collagen, we proposed this structure as a new model for collagen in 1977 (Okuyama et al., Polym J 1977, 9, 341–343). These two structural models were refined against observed continuous intensity data from native collagen using a linked‐atom least‐squares method. It was found that the diffraction data from native collagen could be explained by the 7/2‐helical model better than, or at least the same as, the prevailing 10/3‐helical model. Together with the evidence that recent single crystal analyses of many model peptides have supported the 7/2‐helical model and there was no such active support for the 10/3‐helical model, it was concluded that the average molecular structure of native collagen seems to be closer to the 7/2‐helical symmetry than the other one. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 181–191, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Identification of triterpenoid compounds of Centella asiatica by thin‐layer chromatography and mass spectrometry
Authors: Bonfill Mercè , Mangas Susana , Cusidó Rosa M , Osuna Lidia , Piñol M. Teresa , Palazón Javier 
Published: October 2005

AbstractThe identification of the four principal triterpenoid components of Centella asiatica has been achieved by TLC on silica gel plates and mass spectrometry, as a modification of the method described in the European Pharmacopoeia (5th edn). A combination of ethyl acetate and methanol as the mobile phase was found to be successful in separating these compounds from the rest of the main components of the extract. The spots were detected with anisaldehyde solution. The separated compounds were confirmed by MALDI ‐TOF mass spectrometry. Copyright © 2005 John Wiley & Sons, Ltd.
Inhibition of the biosynthesis of SRP polypeptides and secretory proteins by aflatoxin B1 can disrupt protein targeting
Authors: Singh Jasbir , Dani Harinder M. , Sharma R. , Steinberg Pablo 
Published: October 2005

AbstractCell culture and western blotting studies revealed that aflatoxin B1 (AFB1) inhibits the biosynthesis of two of the constituent polypeptides of signal recognition particle (SRP) (SRP54 and 72). SRP escorts polyribosomes carrying signal peptides from free form in the cytosol to the bound form on endoplasmic reticulum (ER) membrane during protein targeting. These effects of AFB1 on SRP biosynthesis may inhibit the formation of functional SRP. Our experiments have further shown that AFB1 also inhibits the biosynthesis/translocation of a secretory protein, preprolactin, which fails to appear in the lumen of ER consequent to the treatment with this hepatocarcinogen. The results of the experiments presented in this article therefore enable us to infer for the first time that aflatoxin B1 may inhibit the functioning of SRP as an escort and deplete the ER of polyribosomes for secretory protein synthesis. As these secretory proteins are important components of the plasma membrane, gap junctions and intercellular matrix, their absence from these locations could disturb cell to cell communication leading to tumorigenesis. Copyright © 2005 John Wiley & Sons, Ltd.
A microscopic study of kidney tissue in familial mediterranean fever patients
Authors: Sarı Kılıçaslan Seda M. , Ayvalı Cevat , Taştan Hakkı 
Published: October 2005

AbstractFamilial Mediterranean Fever (FMF) is an autosomal recessive hereditary disease leading mostly to renal failure and nephrotic syndrome. The ultrastructure of kidney has not been fully investigated in FMF associated renal disease. The aim of this study is to provide further evidence on the ultrastructure of kidney in patients with FMF who suffer from renal disease. Renal biopsies obtained from two patients who were diagnosed with FMF renal disease complications were examined. Examination of renal tissue by light and electron microscopy identified degenerations both in tubules and the filtration barrier. Foot processes were partly effaced. Amorphous material was found in thickened glomerular basement membranes. Fibrous material deposits in thick Bowman's capsule wall were also seen. Finally, degeneration in the form of folding of plasma membrane and vacuolization as well as fusion in mitochondria cristae, was observed. Accumulation of tissue remnants in the lumen was also found in tubules. Copyright © 2005 John Wiley & Sons, Ltd.
A multi‐biomarker analysis of DNA damage in automobile painters
Authors: Testa A. , Festa F. , Ranaldi R. , Giachelia M. , Tirindelli D. , De Marco A. , Owczarek M. , Guidotti M. , Cozzi R. 
Published: October 2005

AbstractThe genotoxic effects associated with automobile painting were analyzed using a panel of biomarkers. Chromosomal aberrations (CAs), sister chromatid exchange (SCE), and micronuclei were evaluated in 25 car painters (12 smokers, 13 nonsmokers) working in different automobile paint‐shops in Italy and in 37 control subjects. The controls were healthy blood donors (14 smokers, 23 non‐smokers) that were matched with the experimental population for gender and age. Air samples were analyzed regularly at the work places, and elevated concentrations of benzene and toluene were detected consistently. The exposed group had higher frequencies of CAs (both chromosome‐ and chromatid‐type), micronuclei, and SCE (P < 0.5 – P < 0.001). Furthermore, exposed and control subjects were also genotyped for GSTM1 and GSTT1 polymorphism. No significant associations were detected between the biomarker responses and either the GSTM1 or GSTT1 genotype of the subjects, but the small sample size does not allow definite conclusions on the relationship between the genetic polymorphism and the biomarkers. The results indicate that automobile painters have increased levels of clastogenic and possible aneugenic damage and that smoking may be a confounding factor for the responses. Environ. Mol. Mutagen., 2005. © 2005 Wiley‐Liss, Inc.
Towards a methodology for the characterization of fire resistive materials with respect to thermal performance models
Authors: Bentz Dale P. , Prasad Kuldeep R. , Yang Jiann C. 
Published: October 2005

AbstractA methodology is proposed for the characterization of fire resistive materials with respect to thermal performance models. Typically in these models, materials are characterized by their densities, heat capacities, thermal conductivities, and any enthalpies (of reaction or phase changes). For true performance modelling, these thermophysical properties need to be determined as a function of temperature for a wide temperature range from room temperature to over 1000°C. Here, a combined experimental/theoretical/modelling approach is proposed for providing these critical input parameters. Particularly, the relationship between the three‐dimensional microstructure of the fire resistive materials and their thermal conductivities is highlighted. Published in 2005 by John Wiley & Sons, Ltd.
TRAIL‐induced death of human adult oligodendrocytes is mediated by JNK pathway
Authors: Jurewicz Anna , Matysiak Mariola , Andrzejak Stanisław , Selmaj Krzysztof 
Published: October 2005

AbstractTumor necrosis‐related apoptosis‐inducing ligand (TRAIL) induces apoptosis of oligodendrocytes, target cells of immune attack in multiple sclerosis (MS). TRAIL‐induced human oligodendrocyte (hOL) death depends on TRAIL ligation with its receptor 1 (TRAIL‐R1). However, the intracellular signaling initiated with ligation of TRAIL‐R1 in hOLs is unknown. We defined that intracellular transduction signaling involved in TRAIL‐induced death of hOLs is associated with strong activation of c‐jun NH2‐terminal kinase (JNK) and a dominant negative mutant of MKK4/SEK1, MAP kinase upstream of JNK, inhibited TRAIL‐induced apoptosis of hOLs. The immunoprecipitation experiments showed that JNK3 isoform was predominantly activated upon hOLs exposure to TRAIL and JNK‐3 activation occurred before mitochondrial membrane dysfunction. The other mitogen‐activated protein kinase p38 and ERK, as well as calpains and serine proteases, were not activated during TRAIL‐induced hOL death. Accordingly, the calpain inhibitor, ZLLY.FMK, p38 kinase inhibitor, SB 203580, and serine proteases inhibitor, TPCK, did not protect hOLs from TRAIL‐induced apoptosis. These results demonstrate that JNK pathway is critically involved in hOL death induced by TRAIL and might have significant importance in designing new molecules to protect immune‐mediated hOLs demise. © 2005 Wiley‐Liss, Inc.
Cell cycle inhibitors p21 and p16 are required for the regulation of Schwann cell proliferation
Authors: Atanasoski Suzana , Boller Danielle , De Ventura Lukas , Koegel Heidi , Boentert Matthias , Young Peter , Werner Sabine , Suter Ueli 
Published: October 2005

AbstractRegulated cell proliferation is a crucial prerequisite for Schwann cells to achieve myelination in development and regeneration. In the present study, we have investigated the function of the cell cycle inhibitors p21 and p16 as potential regulators of Schwann cell proliferation, using p21‐ or p16‐deficient mice. We report that both inhibitors are required for proper withdrawal of Schwann cells from the cell cycle during development and following injury. Postnatal Schwann cells express p21 exclusively in the cytoplasm, first detectable at postnatal day 7. This cytoplasmic p21 expression is necessary for proper Schwann cell proliferation control in the late development of peripheral nerves. After axonal damage, p21 is found in Schwann cell nuclei during the initiation of the proliferation period. This stage is critically regulated by p21, since loss of p21 leads to a strong increase in Schwann cell proliferation. Unexpectedly, p21 levels are upregulated in this phase suggesting that the role of p21 may be more complex than purely inhibitory for the Schwann cell cycle. However, inhibition of Schwann cell proliferation is the overriding crucial function of p21 and p16 in peripheral nerves as revealed by the consequences of loss‐of‐function in development and after injury. Different mechanisms appear to underlie the inhibitory function, depending on whether p21 is cytoplasmic or nuclear. © 2005 Wiley‐Liss, Inc.
Systemic injections of lipopolysaccharide accelerates myelin phagocytosis during Wallerian degeneration in the injured mouse spinal cord
Authors: Vallières Nicolas , Berard Jennifer L. , David Samuel , Lacroix Steve 
Published: October 2005

AbstractThe phagocytic cell response within the injured spinal cord is inefficient, allowing myelin debris to remain for prolonged periods of time within white matter tracts distal to the injury. Several proteins associated with this degenerating myelin are inhibitory to axon growth and therefore prevent severed axons from regenerating. Inflammatory agents such as lipopolysaccharide (LPS) can stimulate both the migration and phagocytic activity of macrophages. Using in situ hybridization, we found that the expression of the LPS membrane receptor, CD14, was enhanced in the mouse dorsal column following a dorsal hemisection. Double labeling studies showed that microglia and macrophages are the two major cell types expressing CD14 mRNA following spinal cord injury (SCI). We therefore tested whether systemic injections of LPS would increase the number and phagocytic activity of macrophages/microglia in the ascending sensory tract (AST) of the mouse dorsal column following a dorsal hemisection. Mice were treated daily via intraperitoneal injections of either LPS or phosphate‐buffered saline (PBS). At 7 days post‐SCI, greater numbers of activated mononuclear phagocytes were present in the AST undergoing Wallerian degeneration (WD) in LPS‐treated animals compared with controls. Animals treated with LPS also exhibited greater Oil Red O staining, which is specific for degenerating myelin and macrophages phagocytosing myelin debris. Myelin clearance was confirmed at 7 days using Luxol Fast Blue staining and on toluidine blue‐stained semi‐thin sections. These results indicate that it is possible to manipulate the innate immune response to accelerate myelin clearance during WD in the injured mouse spinal cord. © 2005 Wiley‐Liss, Inc.
Differential oxidative stress in oligodendrocytes and neurons after excitotoxic insults and protection by natural polyphenols
Authors: Ibarretxe Gaskon , Sánchez‐Gómez María Victoria , Campos‐Esparza María Rosario , Alberdi Elena , Matute Carlos 
Published: October 2005

AbstractOligodendrocytes are vulnerable to overactivation of both their AMPA receptors and their high‐ and low‐affinity kainate receptors. Depending on the intensity of the insult and the type of receptor activated, excitotoxic oligodendrocyte death mediated by these receptors has different characteristics. One important consequence at a cellular level is the ensuing oxidative stress, related to Ca2+‐dependent alterations in mitochondrial functioning. We observed that oxidative stress associated with selective AMPA receptor activation is much higher than that associated with the selective activation of high‐ and low‐affinity kainate receptors. Moreover, excitotoxic insults generate more intense oxidative stress in oligodendrocytes than in cortical neurons, though similar alterations in [Ca2+]i and mitochondrial potential were observed in both cell types. Nanomolar concentrations of mangiferin and morin, two natural polyphenols with antioxidant properties, partially protect oligodendrocytes as well as cortical neurons from mild, but not intense, insults mediated by AMPA receptors. In addition to presenting oxygen radical scavenging activity, mangiferin and morin attenuate the intracellular Ca2+ overload subsequent to the activation of AMPA receptors, a mechanism that may contribute to their protective properties. The inclusion of these antioxidant agents in therapeutic strategies for the treatment of diseases in which oligodendrocyte as well as neuron loss occurs may prove to be beneficial. © 2005 Wiley‐Liss, Inc.
Simvastatin affects cell motility and actin cytoskeleton distribution of microglia
Authors: Kuipers Hedwich F. , Rappert Angelika A.C. , Mommaas A. Mieke , Van Haastert Elise S. , Van Der Valk Paul , Boddeke Hendrikus W.G.M. , Biber Knut P.H. , Van Den Elsen Peter J. 
Published: October 2005

AbstractStatin treatment is proposed to be a new potential therapy for multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system. The effects of statin treatment on brain cells, however, are hardly understood. We therefore evaluated the effects of simvastatin treatment on the migratory capacity of brain microglial cells, key elements in the pathogenesis of MS. It is shown that exposure of human and murine microglial cells to simvastatin reduced cell surface expression of the chemokine receptors CCR5 and CXCR3. In addition, simvastatin treatment specifically abolished chemokine‐induced microglial cell motility, altered actin cytoskeleton distribution, and led to changes in intracellular vesicles. These data clearly show that simvastatin inhibits several immunological properties of microglia, which may provide a rationale for statin treatment in MS. © 2005 Wiley‐Liss, Inc.
Grindability of cast Ti–Hf alloys
Authors: Kikuchi Masafumi , Takahashi Masatoshi , Sato Hideki , Okuno Osamu , Nunn Martha E. , Okabe Toru 
Published: October 2005

AbstractAs part of our systematic studies characterizing the properties of titanium alloys, we investigated the grindability of a series of cast Ti–Hf alloys. Alloy buttons with hafnium concentrations up to 40 mass% were made using an argon‐arc melting furnace. Each button was cast into a magnesia‐based mold using a dental titanium casting machine; three specimens were made for each metal. Prior to testing, the hardened surface layer was removed. The specimens were ground at five different speeds for 1 min at 0.98 N using a carborundum wheel on an electric dental handpiece. Grindability was evaluated as the volume of metal removed per minute (grinding rate) and the volume ratio of metal removed compared to the wheel material lost (grinding ratio). The data were analyzed using ANOVA. A trend of increasing grindability was found with increasing amounts of hafnium, although there was no statistical difference in the grindability with increasing hafnium contents. We also found that hafnium may be used to harden or strengthen titanium without deteriorating the grindability. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Development of a sustained‐release system for perivascular delivery of dipyridamole
Authors: Zhu Weiwei , Masaki Takahisa , Bae You Han , Rathi Ramesh , Cheung Alfred K. , Kern Steven E. 
Published: October 2005

AbstractVascular access grafts implanted in dialysis patients are prone to failure in the long‐term because of stenosis and occlusion caused by neointimal hyperplasia. Local delivery of antiproliferative drugs may be effective to prevent this consequence while minimizing the systemic side effects they cause. We developed a combination of poly(lactide‐co‐glycolide) (PLGA) microspheres with ReGel®, an injectable copolymer, as a sustained‐release system for perivascular delivery of an antiproliferative drug, dipyridamole. Dipyridamole‐incorporated PLGA microspheres with various molecular weights (MWs) of PLGA were prepared by oil‐in‐water emulsion method. Encapsulation efficiency and surface morphology of microspheres were characterized. In vitro release kinetics of dipyridamole from ReGel or from microspheres/ReGel was experimentally determined. Without microspheres, 40% of the dipyridamole was released from ReGel as an initial burst in the first 3 days followed by continuous release in the subsequent 2 weeks. The use of PLGA microspheres decreased the initial burst and extended dipyridamole release from 23 to 35 days with increasing MW of PLGA. The highest MW PLGA showed a lag time of 17 days before consistent drug release occurred. Mixing microspheres and ReGel with two different MW PLGA achieved a continuous release for 35 days with little initial burst. In vivo release of dipyridamole from microspheres/ReGel exhibited a comparable release pattern to that seen in vitro. This injectable platform is a promising technique for sustained perivascular delivery of antiproliferative drugs. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Improved proton affinity measurements for proline and modified prolines using triple quadrupole and ion trap mass spectrometers
Authors: Mezzache S. , Bruneleau N. , Vekey K. , Afonso C. , Karoyan P. , Fournier F. , Tabet J.‐C. 
Published: October 2005

AbstractProton affinity (PA) of compounds such as proline, cis‐3‐methylproline, cis‐3‐ethylproline, cis‐3‐isopropylproline and cis‐3‐isopentanylproline was determined by kinetic method with amines as the reference bases. The effective temperatures determined using ion trap and triple quadrupole mass spectrometers were found to be significantly different. In the case of the triple quadrupole instruments, the effective temperature depends significantly on the collision energy. The influence of the apparent basicity (GBapp) on the effective temperature may be used to estimate the difference in protonation entropy (ΔΔS°) between the sample and reference compounds. In case of the ion trap mass spectrometer, the variation of the effective temperature as a function of the excitation amplitude is small, so it is difficult to account for the contribution of the entropy effects to the proton affinity value. A better estimation of the PA and ΔΔS° values for the investigated molecules is obtained by combining the GBapp and Teff data pairs that are obtained from both the mass spectrometers. Copyright © 2005 John Wiley & Sons, Ltd.
A novel approach to perform metabolite screening during the quantitative LC–MS/MS analyses of in vitro metabolic stability samples using a hybrid triple‐quadrupole linear ion trap mass spectrometer
Authors: Shou Wilson Z. , Magis Lisa , Li Austin C. , Naidong Weng , Bryant Matthew S. 
Published: October 2005

AbstractIn vitro metabolic stability experiments using microsomes or other liver preparations are important components in the discovery and lead‐optimization stages of compound selection in the pharmaceutical industry. Currently, liquid chromatography–tandem mass spectrometric (LC–MS/MS) support of in vitro metabolic stability studies primarily involves the monitoring of disappearance of parent compounds, using selected reaction monitoring (SRM) on triple‐quadrupole instruments. If moderate to high turnover is observed, separate metabolite identification experiments are then conducted to characterize the biotransformation products. In this paper, we present a novel method to simultaneously perform metabolite screening in addition to the quantitative stability measurements, both within the same chromatographic run. This is accomplished by combining SRM and SRM‐triggered, information‐dependent acquisition (IDA) of MS/MS spectra on a hybrid triple‐quadrupole linear ion trap (QqQLIT) mass spectrometer. Microsomal stability experiments using model compounds, bufuralol, propranolol, imipramine, midazolam, verapamil and diclofenac, were used to demonstrate the applicability of our approach. This SRM + SRM‐IDA approach generated metabolic stability results similar to those obtained by conventional SRM‐only approach. In addition, MS/MS spectra from potential metabolites were obtained with the enhanced product ion (EPI) scan function of LIT during the same injection. These spectra were correlated to the spectra of parent compounds to confirm the postulated structures. The time–concentration profiles of identified metabolites were also estimated from the acquired data. This approach has been successfully used to support discovery programs. Copyright © 2005 John Wiley & Sons, Ltd.