bluuebunny/crossref_metadata_2025_split huggingface dataset:
The chromatin of differentiating erythroblasts is cleaved into large size fragments independent of caspase activated DNase and apoptosis inducing factor
Authors: Hristoskova Sashka , Holzgreve Wolfgang , Hahn Sinuhe , Rusterholz Corinne 
Published: May 2007

AbstractErythroblast cell differentiation involves self‐controlled and limited nuclear proteolysis prior nucleus loss. Early evidence suggests that apoptotic‐like pathways are activated during this process. The chromatin of developing erythroblasts becomes fragmented in vivo, however, the exact mechanisms and molecules involved remain elusive. In this study, erythroblasts were differentiated in culture from CD34‐enriched umbilical cord blood progenitor cells and the characteristics of DNA fragmentation were examined. This analysis shows that the chromatin of differentiating erythroblasts is cleaved into discrete fragments of 50–200 kb. This process most likely involves one or several endonucleases as we detect in vivo double strand DNA cleavage. However, major players of the apoptotic DNA degradation, caspase activated DNase and apoptosis inducing factor, are not activated in these cells. Therefore, our data suggests that erythroblast chromatin degradation may involve enzymes distinct form those active in apoptotic cells. J. Cell. Physiol. 213: 490–494, 2007. © 2007 Wiley‐Liss, Inc.
Chromatin compaction and cell death by high molecular weight FGF‐2 depend on its nuclear localization, intracrine ERK activation, and engagement of mitochondria
Authors: Ma Xin , Dang Xitong , Claus Peter , Hirst Cheryl , Fandrich Robert R. , Jin Yan , Grothe Claudia , Kirshenbaum Lorrie A. , Cattini Peter A. , Kardami Elissavet 
Published: May 2007

AbstractFibroblast growth factor 2 (FGF‐2) is produced as CUG‐initiated, 22–34 kDa or AUG‐initiated 18 kDa isoforms (hi‐ and lo‐FGF‐2, respectively), with potentially distinct functions. We report that expression of hi‐FGF‐2 in HEK293 cells elicited chromatin compaction preceding cell death with apoptotic features. Nuclear localization of the intact protein was required as expression of a non‐nuclear hi‐FGF‐2 mutant failed to elicit chromatin compaction. Equally ineffective, despite nuclear localization, was the over‐expression of the 18 kDa core sequence (lo‐FGF‐2). Chromatin compaction by hi‐FGF‐2 was accompanied by increased cytosolic cytochrome C, and was attenuated either by over‐expression of Bcl‐2 or by a peptide inhibitor of the pro‐apoptotic protein Bax. In addition hi‐FGF‐2 elicited sustained activation of total and nuclear extracellular signal regulated kinase (ERK1/2) by an intracrine route, as it was not prevented by neutralizing anti‐FGF‐2 antibodies. Inhibition of the ERK1/2 activating pathway by dominant negative upstream activating kinase, or by PD 98059, prevented chromatin compaction by hi‐FGF‐2. ERK1/2 activation was not affected by the Bax‐inhibiting peptide suggesting that it occurred upstream of mitochondrial involvement. We conclude that the hi‐FGF‐2‐induced chromatin compaction and cell death requires its nuclear localization, intracrine ERK1/2 activation and mitochondrial engagement. J. Cell. Physiol. 213:690–698. © 2007 Wiley‐Liss, Inc.
Sperm morphology of the eurasian beaver, Castor fiber: An example of a species of rodent with highly derived and pleiomorphic sperm populations
Authors: Bierla Joanna B. , Gizejewski Zygmunt , Leigh Christopher M. , Ekwall Hans , Söderquist Lennart , Rodriguez‐Martinez Heriberto , Zalewski Kazimierz , Breed William G. 
Published: May 2007

AbstractThe structural organization of the spermatozoon from the Eurasian beaver, Castor fiber (Family: Castoridae), was determined and compared to that of other sciuromorph rodents. The beaver spermatozoon has a head, which is variable in form but usually paddle‐shaped, with a small nucleus and very large acrosome, and a tail that is relatively short compared to that of most other rodents. Transmission electron microscopy indicates that in most testicular spermatozoa the acrosome projects apically, although in a few it becomes partly flexed. During the final stages of maturation, however, the acrosome becomes highly folded so that the apical segment comes to lie alongside part of the acrosome that occurs lateral to the nucleus, with, in some cases, fusion taking place between the outer acrosomal membranes. The sperm nucleus is wedge‐shaped, being broader basally and narrowing apically with an occasional large nuclear vacuole occurring. This spermatozoon structure is markedly different from that found in the other species of Geomyoidea, which is the sister group of the Castoridae. The findings thus emphasize the highly divergent nature of the beaver spermatozoon and demonstrate that, within the proposed Infraorder Castorimorpha, very large differences in sperm structure have evolved. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.
P2Y receptor‐activating nucleotides modulate cellular reactive oxygen species production in dissociated hippocampal astrocytes and neurons in culture independent of parallel cytosolic Ca2+ rise and change in mitochondrial potential
Authors: Kahlert Stefan , Blaser Till , Tulapurkar Mohan , Reiser Georg 
Published: May 2007

AbstractWith mixed cultures of hippocampal astrocytes and neurons, we investigated the influence of nucleotides on cytosolic Ca2+ level, generation of reactive oxygen species (ROS), and mitochondrial potential. We employed ATP and four purine/pyrimidine derivates, which are P2Y receptor subtype‐preferring agonists. Stimulation with ATP, a P2Y1/2/4 receptor agonist in rat, caused a large cytosolic Ca2+ increase in astrocytes and a considerably smaller Ca2+ response in neighboring neurons. The P2Y1 receptor antagonist MRS2179 completely blocked the ATP‐induced Ca2+ response in astrocytes and neurons. Application of ATP significantly reduced the mitochondrial potential in neurons, which was not inhibited by MRS2179. Interestingly, MRS2179 mediated a mitochondrial depolarization without affecting the cytosolic Ca2+ level. Stimulation with UDP, a P2Y6 receptor agonist; UTP, a P2Y2/4 receptor agonist; 2MeSATP, a P2Y1 receptor agonist; or 2MeSADP, a P2Y1/12/13 receptor agonist, evoked significant Ca2+ responses in astrocytes but small Ca2+ responses in neurons. In astrocytes, there was an inverse relationship between the amplitude of the cytosolic Ca2+ peak and the rate of ROS generation in response to nucleotide application. Activation with UDP resulted in the highest ROS generation that we detected, whereas 2MeSADP and 2MeSATP reduced the ROS generation below the basal level. 2MeSADP and UDP caused mitochondrial depolarization of comparable size. Thus, neither in astrocytes nor in neurons did the degree of mitochondrial depolarization correlate with ROS generation. Nucleotides acting via P2Y receptors can modulate ROS generation of hippocampal neurons without acutely changing the cytosolic Ca2+ level. Thus, ROS might function as a signaling molecule upon nucleotide‐induced P2Y receptor activation in brain. © 2007 Wiley‐Liss, Inc.
Neuroprotective effects of pituitary adenylate cyclase–activating polypeptide (PACAP) in MPP+‐induced alteration of translational control in Neuro‐2a neuroblastoma cells
Authors: Deguil Julie , Jailloux David , Page Guylène , Fauconneau Bernard , Houeto Jean‐Luc , Philippe Michel , Muller Jean‐Marc , Pain Stéphanie 
Published: May 2007

AbstractParkinson's disease (PD) and 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) toxicity are both associated with dopaminergic neuron death in the substantia nigra. Although a variety of evidence has shown that degenerative cells have apoptotic features, the role of apoptosis in disease pathology remains controversial. The 1‐methyl‐4‐phenylpyridinium ion (MPP+), a metabolite of MPTP, was recently shown to alter the expression of proteins involved in translational control. The initiation step of translational control is regulated by a cascade of phosphorylation affecting proteins of the antiapoptotic way controlled by mammalian target of rapamycin (mTOR) and of the proapoptotic way controlled by double‐stranded RNA protein–dependent kinase (PKR). A study showed that MPP+induced an increase in eIF2α phosphorylation, leading to inhibition of protein synthesis. The aims of our study were: (1) to assess the effects of MPP+toxicity on molecular factors of PKR and mTOR signaling pathways in murine neuroblastoma cells, and (2) to examine the ability of VIP and PACAP peptides to counteract the MPP+toxicity. Our findings showed that MPP+induced phosphorylation of eIF2α and significantly reduced the expression of phosphorylated mTOR, p70S6K, eIF4E, and 4E‐BP1, suggesting its toxicity in controlling protein synthesis. Furthermore, the VIP peptide had no effect on either the PKR or the mTOR signaling pathway. On the contrary, the PACAP 27 neuropeptide prevented MPP+‐induced eIF2α phosphorylation and blocked MPP+toxicity in molecular factors of the mTOR pathway. And last, PACAP 27 seemed to protect Neuro‐2a cells from the apoptotic process as assessed by the decreased nuclear condensation after DAPI staining. These results could open new paths of research of PACAP in PD. © 2007 Wiley‐Liss, Inc.
Delayed neurotrophin treatment following deafness rescues spiral ganglion cells from death and promotes regrowth of auditory nerve peripheral processes: Effects of brain‐derived neurotrophic factor and fibroblast growth factor
Authors: Miller Josef M. , Le Prell Colleen G. , Prieskorn Diane M. , Wys Noel L. , Altschuler Richard A. 
Published: May 2007

AbstractThe extent to which neurotrophic factors are able to not only rescue the auditory nerve from deafferentation‐induced degeneration but also promote process regrowth is of basic and clinical interest, as regrowth may enhance the therapeutic efficacy of cochlear prostheses. The use of neurotrophic factors is also relevant to interventions to promote regrowth and repair at other sites of nerve trauma. Therefore, auditory nerve survival and peripheral process regrowth were assessed in the guinea pig cochlea following chronic infusion of BDNF + FGF1 into scala tympani, with treatment initiated 4 days, 3 weeks, or 6 weeks after deafferentation from deafening. Survival of auditory nerve somata (spiral ganglion neurons) was assessed from midmodiolar sections. Peripheral process regrowth was assessed using pan‐Trk immunostaining to selectively label afferent fibers. Significantly enhanced survival was seen in each of the treatment groups compared to controls receiving artificial perilymph. A large increase in peripheral processes was found with BDNF + FGF1 treatment after a 3‐week delay compared to the artificial perilymph controls and a smaller enhancement after a 6‐week delay. Neurotrophic factor treatment therefore has the potential to improve the benefits of cochlear implants by maintaining a larger excitable population of neurons and inducing neural regrowth. © 2007 Wiley‐Liss, Inc.
Morphometric analysis of oligodendrocytes in the adult mouse frontal cortex
Authors: Murtie Joshua C. , Macklin Wendy B. , Corfas Gabriel 
Published: May 2007

AbstractOligodendrocytes (OLs), the myelinating cells of the central nervous system, have specialized morphologies that subserve their function. Numerous qualitative studies suggest that OLs in different brain regions can differ in their morphological characteristics, including number of branches and internodes, internode length, etc. However, progress in identifying and characterizing the diverse types of OLs and their distribution in the brain has been made difficult by several technical constraints. Here we report a new strategy to analyze OL morphology with a high degree of quantitative power and throughput. We used confocal microscopy and three‐dimensional cell tracing software to study OLs in the frontal cortex of mice expressing enhanced green fluorescent protein (eGFP) under the control of the proteolipid protein (Plp) gene promoter. Three‐dimensional reconstructions were then used to analyze and quantify cell morphology, including total process length, total process surface area, total internode length, number of primary processes, number of branch points, and number of internodes. In addition, these reconstructions were subjected to Sholl analysis, which allows for the quantitative measure of OL arbor complexity. By using this approach, we identified and characterized a previously undescribed population of small OLs with a compact but complex morphology that includes numerous branching processes and a large number of short internodes. Our data suggest that other populations of OLs remain to be identified and characterized and that the tools we have developed could help in the process of characterizing them. © 2007 Wiley‐Liss, Inc.
Optimizing human post‐mortem brain tissue gene expression profiling in Parkinson's disease and other neurodegenerative disorders: From target “fishing” to translational breakthroughs
Authors: Papapetropoulos Spiridon , Shehadeh Lina , McCorquodale Donald 
Published: May 2007

AbstractInsights on the etiopathogenesis of common neurodegenerative disorders such as Parkinson's disease (PD) and Alzheimer's disease (AD) have been largely based on the discovery of gene mutations in genetically determined forms. Although these discoveries have been helpful in elucidating the basic molecular pathogenesis of familial forms, they represent a small fraction of cases, leaving the large majority classified as idiopathic. In the postgenomic era, brain tissue gene expression profiling has allowed relative quantitative assessment of thousands of genes simultaneously from one tissue sample, providing clues for novel candidate genes and processes implicated in neurodegenerative disorders. Some remain critical of “fishing expedition” science, but gene expression profiling is a discovery‐based procedure well suited for the study of largely idiopathic and multifactorial diseases. However, the technology is still under development, and many methodological and biological aspects contribute to the heterogeneous results obtained from gene expression profiling. In this Review, we discuss the advantages and limitations of this technology in simple terms and identify the key variables that influence/limit gene expression profiling‐derived translational breakthroughs in neurodegenerative diseases. © 2007 Wiley‐Liss, Inc.
High‐pressure Raman and photoluminescence of highly anisotropic CdS nanowires
Authors: Fan H. M. , Ni Z. H. , Feng Y. P. , Fan X. F. , Shen Z. X. , Zou B. S. 
Published: May 2007

AbstractRaman and photoluminescence of CdS nanowires of diameter 80 nm and lengths up to several tens of micrometers were studied at pressure up to 60 kbar using a Jobin‐Yvon T64000 micro‐Raman system in conjunction with the diamond‐anvil cell technique. The phase transition pressure of wurtzite to rock salt was observed at 38 kbar, which is higher than that of bulk CdS. In contrast with the transition pressure of different‐sized CdS nanocrystal, this elevated phase transition pressure cannot be explained well by the size effect. Thus the contribution of particle morphology of such a system, which represents the low‐energy surface structure, should be considered. The pressure dependence of photoluminescence is also discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Raman and infrared studies of synthetic Maya pigments as a function of heating time and dye concentration
Authors: Manciu F. S. , Reza L. , Polette L. A. , Torres B. , Chianelli R. R. 
Published: May 2007

AbstractMaya Blue is a famous indigo‐based pigment produced by the ancient Mayas. The organic/inorganic complexes inspired by Maya Blue have led to a new class of surface compounds that have novel applications to pigment industries. Materials analyzed in the present work are made by a synthetic route, and demonstrate chemical stability similar to that of the ancient Maya Blue samples. However, we have learned that stable complexes can be synthesized at much higher dye concentrations than used by the Mayas. Analysis by FT‐Raman and FT‐IR spectroscopy demonstrates the partial elimination of the selection rules for the centrosymmetric indigo, indicating distortion of the molecule. This distortion accounts for the observed color changes, as the molecular orbital structure is modified, allowing the complex to stabilize. The spectroscopic data also shows the disappearance of the indigo NH bonding, as the organic molecules incorporate into palygorskite material. A structural change of indigo to dehydroindigo during heating is suggested by this result. Infrared data confirm the loss of zeolitic water and a partial removal of structural water after the heating process. Evidence of bonding between cationic aluminum and dehydroindigo through oxygen and nitrogen is revealed by FT‐Raman measurements at higher dye concentrations. Copyright © 2007 John Wiley & Sons, Ltd.
Expression of enhanced green fluorescent protein in porcine‐ and bovine‐cloned embryos following interspecies somatic cell nuclear transfer of fibroblasts transfected by retrovirus vector
Authors: Uhm Sang Jun , Gupta Mukesh Kumar , Kim Teoan , Lee Hoon Taek 
Published: May 2007

AbstractInterspecies somatic cell nuclear transfer (iSCNT) has emerged as an important tool for studying nucleo‐cytoplasmic interactions and cloning of animals whose oocytes are difficult to obtain. This study was designed to explore the feasibility of employing transgenic fibroblasts as donor cells for iSCNT. The study examined the chromatin morphology, in vitro development, and expression of an enhanced green fluorescent protein (EGFP) gene in porcine‐ and bovine‐cloned embryos produced by iSCNT of fetal fibroblast transfected with a pLNβ‐EGFP retroviral vector. Parthenogenetic and transfected or nontransfected intraspecies SCNT embryos were used as controls for comparison. Analysis of data revealed that xenogenic oocyte was able to reprogram somatic cells of different genus and supports their in vitro development to the blastocyst stage. However, the developmental rates of transgenic iSCNT embryos to the blastocyst stage were significantly lower than those of intraspecies SCNT embryos. The reduction in development rates was however, not due to integration of the transgene as the lower (P < 0.05) development rates of the intraspecies SCNT porcine or bovine embryos did not differ between transgenic and nontransgenic groups. Expression of EGFP was observed in 100% of blastocysts and mosaicism was not observed. Furthermore, after iSCNT of porcine or bovine donor nuclei into xenogenic ooplasm, patterns of nuclear remodeling in reconstructed embryos were similar. In conclusion, our data demonstrated the feasibility of producing transgenic iSCNT embryos. To our knowledge, this is the first report of transgenic cloned embryo production by iSCNT approach. In the future, this may provide a powerful research tool for studying developmental events in domestic animals and provide marked cell lines for other genetic manipulations. Mol. Reprod. Dev. 74: 1538–1547, 2007. © 2007 Wiley‐Liss, Inc.
Numerical analysis of 1‐D compression wave propagation in saturated poroelastic media
Authors: Qiu Tong , Fox Patrick J. 
Published: May 2007

AbstractA numerical procedure is presented for the simulation of 1‐D compression wave propagation in saturated poroelastic media. The media are modelled as a two‐phase system consisting of compressible fluid and solids. Viscous coupling forces resulting from the relative motion between phases are characterized as Darcy type. The numerical procedure can account for effects of axial strain, nonlinear material behaviour, and various drained and undrained boundary conditions. Time integration is carried out explicitly and isothermal conditions are assumed. The method is capable of modelling shock
wave fronts without introducing artificial viscosity. Numerical results are in close agreement with analytical solutions for several simplified cases and indicate that mass coupling may have important effects on fluid velocity and wave speed. Corresponding effects on solid velocity and wave speed are much smaller. Numerical results also indicate that damping occurs in a saturated poroelastic column and is dependent on the value of hydraulic conductivity. Copyright © 2007 John Wiley & Sons, Ltd.
Evaluation of commonly used rules for detecting “steady state” in computer simulation
Authors: Gafarian A. V. , Ancker C. J. , Morisaku T. 
Published: May 2007

AbstractA definition of the problem of the initial transient with respect to the steady‐state mean value has been formulated. A set of criteria has been set forth by which the efficaacy of any proposed rule may be assessed. Within this framework, five heuristic rules for predicting the approximate end of transiency, four of which have been quoted extensively in the simulation literature, have been evaluated in the M/M/1 situation. All performed poorly and are not suitable for their intended use.
Predicting the cost performance of inventory control systems by retrospective simulation
Authors: MacCormick Alastair 
Published: May 2007

AbstractWhen an inventory‐control system is designed to utilized statistical demand information in computing an (s,S) policy, it may be necessary to use performance forecasts to calibrate the relationship between control parameters and performance measures. Using a simulation model to test prediction by retrospective simulation we estimated the bias and variance of forecasts for expected costs and other operating characteristics. The results show the sensitivity of the prediction bias to changes in demand, cost, and lead time parameters and to choices made in system design.
The optimum design of multivariate acceptance sampling plans
Authors: Chapman S. C. , Schmidt J. W. , Bennett G. K. 
Published: May 2007

AbstractA model is developed which may be used to determine the expected total cost of quality control per inspection lot under acceptance sampling by variables where several characteristics are to be simultaneously controlled. Optimization of the model is accomplished through the application of a conventional search procedure. The sensitivity of the model and the optimum solution to the shape of the underlying probability distributions is discussed and associated analyses are presented through an example.
Markov chain with taboo states and reliability
Authors: Sriwastav G. L. , Pandit S. N. N. 
Published: May 2007

AbstractA computationally feasible matrix method is presented to find the first‐passage probabilities in a Markov chain where a set of states is taboo during transit. This concept has been used to evaluate the reliability of a system whose changes in strength can be thought of as a Markov chain, while the environment in which it is functioning generates stresses which can also be envisaged as another Markov chain.
A note on the limitations of goal programming as observed in resource allocation for marine environmental protection
Authors: Harrald J. , Leotta J. , Wallace W. A. , Wendell R. E. 
Published: May 2007

AbstractAfter first formulating the problem of the Marine Environmental Protection program of the Coast Guard as a multiple‐objective linear program, we investigate the applicability and limitations of goal programming. We point out how the preemptive goal‐programming approach is incompatible with utility preferences. Then we observe the tendency of optimal solutions for standard linear goal programs to occur at extreme points. We also note problems of more general approaches, such as dealing with additively separable approximations to preferences.