bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface chemistry and biological responses to synthetic octacalcium phosphate
Authors: Suzuki Osamu , Kamakura Shinji , Katagiri Takenobu 
Published: October 2005

AbstractOctacalcium phosphate (OCP) has been suggested as a precursor of biological apatite in bone, dentin, and cementum because its existence explains the nonstoichiometry of apatite crystals in their compositions. Synthetic inorganic calcium phosphate compounds have been used clinically to fill bone defects, and sintered hydroxyapatite (HA) and beta‐tricalcium phosphate (β‐TCP), bone substitute materials, are known to be osteoconductive, with β‐TCP also being bioresorbable. Nonsintered synthetic OCP has been shown to enhance bone regeneration accompanied by conversion into hydrolyzed apatitic products in situ and biodegradation. The surfaces of the OCP implant and the converted apatite seem to be continuously exposed to biological constituents, such as extracellular matrices, inorganic biominerals, and cellular components. This article reviews the surface reaction of OCP implants and the biological responses, such as experimentally stimulated bone formation on synthetic OCP, the mechanism of OCP hydrolysis into apatite, and the adsorption of biomolecules onto OCP and the converted apatite, of particular interest in reactive bone induction with synthetic OCP implants. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Effect of prestrain on martensitic transformation in a Ti46.4Ni47.6Nb6.0 superelastic alloy and its application to medical stents
Authors: Takagi T. , Sutou Y. , Kainuma R. , Yamauchi K. , Ishida K. 
Published: October 2005

AbstractThe effect of applied strain on martensitic transformation in a superelastic Ti46.4Ni47.6Nb6.0 alloy at room temperature was investigated by tensile tests, differential scanning calorimetry measurements, and X‐ray diffraction. Reverse transformation starting (As) and finishing (Af) temperatures increased with the application of tensile‐strain over 13%, the undeformed specimen showing As = −29.2°C and Af = 17.9°C, while the 13% predeformed alloy exhibited As = 37.1°C and Af = 40.2°C. Furthermore, the values of the As and Af for the predeformed alloy almost recovered to those of the undeformed alloy when heated to about 42°C and then showed superelasticity again at room temperature. This characteristic is significant for application in sensors, actuators, and medical devices. Especially, medical stents with such qualities show promise as a new class of self‐expandable stents with both excellent mountability and deliverability. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Over‐expression of heme oxygenase‐1 promotes oxidative mitochondrial damage in rat astroglia
Authors: Song Wei , Su Haixiang , Song Sisi , Paudel Hemant K. , Schipper Hyman M. 
Published: October 2005

AbstractGlial heme oxygenase‐1 is over‐expressed in the CNS of subjects with Alzheimer disease (AD), Parkinson disease (PD) and multiple sclerosis (MS). Up‐regulation of HO‐1 in rat astroglia has been shown to facilitate iron sequestration by the mitochondrial compartment. To determine whether HO‐1 induction promotes mitochondrial oxidative stress, assays for 8‐epiPGF2α (ELISA), protein carbonyls (ELISA) and 8‐OHdG (HPLC‐EC) were used to quantify oxidative damage to lipids, proteins, and nucleic acids, respectively, in mitochondrial fractions and whole‐cell compartments derived from cultured rat astroglia engineered to over‐express human (h) HO‐1 by transient transfection. Cell viability was assessed by trypan blue exclusion and the MTT assay, and cell proliferation was determined by [3H] thymidine incorporation and total cell counts. In rat astrocytes, hHO‐1 over‐expression (×3 days) resulted in significant oxidative damage to mitochondrial lipids, proteins, and nucleic acids, partial growth arrest, and increased cell death. These effects were attenuated by incubation with 1 µM tin mesoporphyrin, a competitive HO inhibitor, or the iron chelator, deferoxamine. Up‐regulation of HO‐1 engenders oxidative mitochondrial injury in cultured rat astroglia. Heme‐derived ferrous iron and carbon monoxide (CO) may mediate the oxidative modification of mitochondrial lipids, proteins and nucleic acids in these cells. Glial HO‐1 hyperactivity may contribute to cellular oxidative stress, pathological iron deposition, and bioenergetic failure characteristic of degenerating and inflamed neural tissues and may constitute a rational target for therapeutic intervention in these conditions. © 2005 Wiley‐Liss, Inc.
A common pathway in differentiation and inflammation: p38 mediates expression of the acute phase SIP24 iron binding lipocalin in chondrocytes
Authors: Ulivi Valentina , Tutolo Giorgia , Mallein‐Gerin Frédéric , Daga Antonio , Cancedda Ranieri , Cancedda Fiorella Descalzi 
Published: October 2005

AbstractSIP24 is an acute phase iron binding lipocalin physiologically expressed in vivo in developing cartilage by prehypertrophic/hypertrophic chondrocytes. Taking advantage of the chondrocytic cell line MC615 and using SIP24 as a marker we investigated the pathways active in cartilage differentiation and inflammation. MC615 cells were cultured as: (i) proliferating prechondrogenic cells expressing type I collagen (ii) differentiated hyperconfluent cells expressing Sox9 and type II collagen. In proliferating cells the pathway PKC/ERK1, ERK2 was activated and SIP24 was not expressed while in differentiated cells the pathway p38/NF‐κB was activated and SIP24 was expressed. Proliferating cells treated with inflammatory agents expressed a large amount of SIP24 and showed activation of p38/NF‐κB pathway and inhibition of PKC/ERK1, ERK2 pathway indicating that in inflammation and differentiation the same factors are activated (p38, NF‐κB) or inactivated (PKC, ERKs). Treatment of proliferating cells with the p38 specific inhibitor SB203580 inhibited the inflammation induced activation of p38 and the synthesis of SIP24. PMA treatment induced activation of PKC, inactivation of p38 and suppression of SIP24 synthesis, suggesting that PKC activation inhibits p38 activation. In differentiated hyperconfluent cells the same factors (p38/NF‐κB/SIP24) are constitutively activated: treatment with inflammatory agents does not increase synthesis of SIP24 while treatment with SB203580 and with PMA does not repress activation of p38 nor synthesis of SIP24. We propose that the SIP24 stress related protein is expressed via p38 activation/NF‐κB recruitment both in chondrocyte differentiation and inflammation and that a signaling pathway active in the acute phase response is physiologically activated in differentiation. © 2005 Wiley‐Liss, Inc.
Limitation of size by hypoxia in the fruit fly Drosophila melanogaster
Authors: Peck Lloyd S. , Maddrell Simon H.P. 
Published: October 2005

AbstractThe size of an organism is of fundamental importance in all biological processes. It dictates many of the critical interactions and physical factors that delimit the envelope within which an organism can grow. We investigated the effects of reduced oxygen on size and development in the fruit fly Drosophila melanogaster, and showed that limiting the oxygen in the environment limits both whole animal and cell size. When oxygen levels were reduced from 20% in nitrogen to 15%, 10% and 7.5%, there was a linear decrease in both male and female mass. Both cell size and cell number decreased in low oxygen, but changes in cell size accounted for a larger proportion of the overall change in fly size. Cell numbers decreased by a maximum of 11% between flies reared in 20% oxygen and those reared in 7.5% oxygen, whereas cell surface area decreased by 17%. Low oxygen levels increased development time and mortality, but reduced fecundity. Reducing the level of oxygen available significantly slowed development times, with flies reared in 10% oxygen emerging on average 1.5 days later than those in 20% oxygen. The effect of oxygen on size is reversible during embryonic and larval development up to the pupal stage, when final size is set. J. Exp. Zool. 303A:968–975, 2005. © 2005 Wiley‐Liss, Inc.
Adaptation of a nematode parasite to living within the mammalian epithelium
Authors: Tilney Lewis G. , Connelly Patricia S. , Guild Gregory M. , Vranich Kelly A. , Artis David 
Published: October 2005

AbstractTrichuris muris is a large metazoan pathogen that has been proposed to live intracellularly within living host intestinal epithelial cells. We sought to determine how Trichuris bores its way through the mucosal epithelium and to elucidate the parasite strategies for taking advantage of this intracellular niche. Since the apical surface of the mucosal epithelium is stabilized by the actin cytoskeleton and cell junctions, it remains intact over the worm following its entry into cells. In contrast, non‐stabilized lateral membranes of the host epithelial cells are ruptured and cells are killed to form an inert syncytial tunnel. The ventral surface of the nematode worm is studded by pores that overlie bacillary cells; these pores penetrate through the cuticle and are in direct contact with host cytoplasm. From scanning electron micrographs of isolated worms, we calculate that each adult contains approximately 50,000 bacillary cells. The apical surface of the bacillary cells is extensively folded into plicae 40 nm in diameter, thereby increasing the surface area many‐fold. Bacillary cells lack organelles for enzyme synthesis and secretion and fail to export protons. However, by confocal light microscopy it was observed that fluorescent macromolecules in excess of 100,000 Da can penetrate into the pores. Taken together, we conclude that the bacillary cells are essential for living inside host epithelium and function predominantly in absorption of soluble molecules from the host mucosal cytoplasm, in essence behaving as an external gut epithelium that is protected from abrasion by the cuticle that surrounds the openings of the bacillary cells. J. Exp. Zool. 303A:927–945, 2005. © 2005 Wiley‐Liss, Inc.
Pigmented epithelium to retinal transdifferentiation and Pax6 expression in larval Xenopus laevis
Authors: Arresta Emiliano , Bernardini Sergio , Bernardini Enrico , Filoni Sergio , Cannata Stefano M. 
Published: October 2005

AbstractThis study examines the retinal transdifferentiation (TD) of retinal pigmented epithelium (RPE) fragments dissected from Xenopus laevis larvae and implanted into the vitreous chamber of non‐lentectomized host eyes. In these experimental conditions, most RPE implants transformed into polarized vesicles in which the side adjacent to the lens maintained the RPE phenotype, while the side adjacent to the host retina transformed into a laminar retina with the photoreceptor layer facing the cavity of the vesicle and with the ganglionar cell layer facing the host retina. The formation of a new retina with a laminar organization is the result of depigmentation, proliferation and differentiation of progenitor cells under the influence of inductive factors from the host retina. The phases of the TD process were followed using BrdU labelling as a marker of the proliferation phase and using a monoclonal antibody (mAbHP1) as a definitive indicator of retina formation. Pigmented RPE cells do not express Pax6. In the early phase of RPE to retinal TD, all depigmented and proliferating progenitor cells expressed Pax6. Changes in the Pax6 expression pattern became apparent in the early phase of differentiation, when Pax6 expression decreased in the presumptive outer nuclear layer (ONL) of the new‐forming retina. Finally, during the late differentiation phase, the ONL, which contains photoreceptors, no longer expressed Pax6, Pax6 expression being confined to the ganglion cell layer and the inner nuclear layer. These results indicate that Pax6 may have different roles during the different phases of RPE to retinal TD, acting as an early retinal determinant and later directing progenitor cell fate. J. Exp. Zool. 303A:958–967, 2005. © 2005 Wiley‐Liss, Inc.
Effects of Low pH acute exposure on survival and gill morphology inTriturus italicuslarvae
Authors: Brunelli Elvira , Tripepi Sandro 
Published: October 2005

AbstractWe examined, from a morphological and ultrastructural point of view, the gill epithelium ofTriturus italicus, both in basal conditions and after acute exposure to low pH. Our analysis of gill morphology began with the aim of determining lethal pH levels; we found that the pH value at which 50% of mortality occurs (LC50) is 4.0. We then investigated the effects of the larvae's exposure to a critical value of pH (pH 4.5).No change was observed in the gill during the first 24 hr. After 48 hr, a cellular response was evident and the gills appeared covered with a dense mucous layer. Observations that were carried out by light microscopy (LM) and electron microscopy, both scanning (SEM) and transmission (TEM), showed considerable histological and ultrastructural changes.As regards the principal filament, the alterations resulted in the presence of an external keratinized layer. More changes affected the mitochondria‐rich cells (MRCs) in both a qualitative and quantitative way; this cell type shows a wide surface and seems to protrude more than the near pavement cells that, in normal conditions, partially cover the MRCs, thus reducing their external surface. The microvilli were extremely lengthened and often anatomized each other. Changes in the secondary filament affected the thickness of the epithelium, which appeared considerably smaller in the gills of the newts exposed to acid stress. The ciliated cells appeared to be more numerous than in the control specimens and the MRCs showed a widening of the apical surface.J. Exp. Zool. 303A:946–957, 2005. © 2005 Wiley‐Liss, Inc.
Stressed mothers lay eggs with high corticosterone levels which produce low‐quality offspring
Authors: Saino Nicola , Romano Maria , Ferrari Raffaella Paola , Martinelli Roberta , Møller Anders Pape 
Published: October 2005

AbstractOrganisms frequently encounter stressful ecological conditions. In vertebrates, a major mechanism of physiological response to stress is mediated by the hypothalamic–pituitary–adrenal axis and results in increased secretion of glucocorticosteroids, which can have adverse consequences on diverse phenotypic traits affecting fitness. Maternal stress may thus have carry‐over effects on progeny if it influences pre‐natal offspring environment in terms of glucocorticosteroid concentration, although this hypothesis has never been tested in any species under field conditions. We manipulated stress experienced by female barn swallows Hirundo rustica, by exposing them to a predator during laying and measured egg corticosterone concentration. Stressed females laid eggs with greater corticosterone concentration than controls exposed to a herbivore. In another experiment, we injected physiological doses of corticosterone in the egg albumen and compared the phenotype of offspring originating from these eggs with their control siblings originating from either sham‐inoculated or unmanipulated eggs and reared in the same nest. Eggs injected with corticosterone had lower hatchability and produced fledglings with smaller body size and slower plumage development than did control eggs. Nestling body size in our study population predicts long‐term survival. Thus, maternal stress impaired offspring phenotype and viability by increasing transmission of glucocorticosteroids to the eggs. This study identifies a novel mechanism mediating early maternal effects whereby maternal stress affects offspring quality. These results are relevant to biological conservation because they disclose a mechanism that can link environmental conditions to population productivity and viability. J. Exp. Zool. 303A:998–1006, 2005. © 2005 Wiley‐Liss, Inc.
Germ cell death in the testis and its relation to spermatogenesis in the wax moth, Galleria mellonella (Lepidoptera: Pyralidae), effects of facultative diapause
Authors: Polanska Marta Anna , Ciuk Marcin Adam , Cymborowski Bronislaw , Bebas Piotr 
Published: October 2005

AbstractThe dichotomous spermatogenesis of many Lepidopterans results in the production of two types of sperm: eupyrene sperm possessing a cell nucleus which participates in fertilisation, and apyrene ones, which lose their nuclei during development and whose function remains a mystery. The goal of our study was to analyse spermatogenesis at the end of the larval development of the wax moth, Galleria mellonella, at an optimal temperature of 30°C as well as to describe how they are affected by diapause brought on by a reduction of temperature to 18°C. Spermatogenesis in non‐diapausing insects did not differ significantly from that described in other species of Lepidoptera, and any differences found were compared against available literature. Based on the results presented, it may be unequivocally stated that changes in spermatogenesis occur in diapause caused by a suboptimal temperature of 18°C. The main effect of diapause observed in the testes is the degeneration of germ cells, immediately following their differentiation from bipotential spermatocytes. Eupyrene cells seem to reach a more advanced stage of development. Due to the absence of secondary eupyrene spermatocytes in the testis of diapausing insects, it may be surmised that the meiotic divisions, which lead to the formation of secondary spermatocytes and eventually spermatids, do not occur, or are somehow altered. Lastly, terminal deoxynucleotidyl transferase (TdT)‐mediated dUTP nick‐end labelling (TUNEL) analyses we performed show that the degenerative changes of eupyrene cells are apoptotic in character. J. Exp. Zool. 303A:1013–1029, 2005. © 2005 Wiley‐Liss, Inc.
Isolation of the Feline α1,3‐Galactosyltransferase Gene, Expression in Transfected Human Cells and its Phylogenetic Analysis
Authors: Roy Bibhuti Bhusan , Jinno‐oue Atsushi , Shinagawa Masahiko , Shimizu Akira , Tamura Kazushi , Shimizu Nobuaki , Tanaka Atsushi , Hoshino Hiroo 
Published: October 2005

AbstractThe enzyme alpha 1,3‐galactosyltransferase (α1,3‐GT), which catalyzes synthesis of terminal α‐galactosyl epitopes (Gal α1,3Gal β1‐4GlcNAc‐R), is produced in non‐primate mammals, prosimians and new‐world monkeys, but not in old‐world monkeys, apes and humans. We cloned and sequenced a cDNA that contains the coding sequence of the feline α1,3‐GT gene. Flow cytometric analysis demonstrated that the α‐galactosyl epitope was expressed on the surface of a human cell line transduced with an expression vector containing this cDNA, and this α‐galactosyl epitope expression subsided by α‐galactosidase treatment. The open reading frame of the feline α1,3‐GT cDNA is 1,113 base pairs in length and encodes 371 amino acids. The nucleotide sequence and its deduced amino acid sequence of the feline α1,3‐GT gene are 88–90% and 85–87%, respectively, similar to the reported sequences of the bovine, porcine, marmoset and cebus monkey α1,3‐GT genes, while they are 88% and 82–83%, respectively, similar to those of the orangutan and human α1,3‐GT pseudogenes, and 81% and 77%, respectively, similar to the murine α1,3‐GT gene. Thus, the α1,3‐GT genes and pseudogenes of mammals are highly similar. Ratios of non‐synonymous nucleotide changes among the primate pseudogenes as well as the primate genes are still higher than the ratios of non‐primates, suggesting that the primate α1,3‐GT genes tend to be divergent. J. Exp. Zool.(Mol. Dev. Evol.) 306B, 2006. © 2005 Wiley‐Liss, Inc.
Dmrt1 expression in response to estrogen treatment in a reptile with temperature‐dependent sex determination
Authors: Murdock Chris , Wibbels Thane 
Published: October 2005

AbstractDmrt1 has been implicated as an important factor in sex determination in all classes of vertebrates, including reptiles with temperature‐dependent sex determination (TSD). Specifically, early embryonic expression of Dmrt1 appears to be an integral part of normal testicular development in vertebrates. Recently, a number of TSD studies have placed Dmrt1 expression at the top of a short list of putative temperature‐sensitive events for TSD. Dmrt1 expression has been shown to be up‐regulated at male‐producing temperatures during the thermosensitive period (TSP) of several TSD reptile species. An interesting finding in Dmrt1 studies of fish and amphibians has been that in species where exogenous steroids can stimulate sex reversal, Dmrt1 expression can also be manipulated by these steroid treatments. In the current study, we examine the effects of exogenous 17β‐estradiol treatment on Dmrt1 expression at male‐producing temperature (26°C) in a reptile with TSD, the red‐eared slider turtle, Trachemys scripta. Previous studies have demonstrated that exogenous estrogens can stimulate sex reversal (at male‐producing temperatures) in this species of turtle. In the current study, T. scripta embryos that received estradiol treatment displayed a significant decrease in Dmrt1 expression during the TSP, while embryos in the control group (no estradiol treatment) showed significant increases in Dmrt1 expression during the TSP. Furthermore, the pattern of Dmrt1 expression for the estradiol‐treated group was similar to the pattern we previously reported for Dmrt1 at female‐producing temperature (31°C). These findings indicate that exogenous estrogen is acting at or before the Dmrt1 event in the sex determination/sex differentiation cascade of T. scripta. Further, the results are consistent with the hypothesis that exogenous estrogen could be exerting its feminizing effect by down‐regulating the expression of Dmrt1. J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006. © 2005 Wiley‐Liss, Inc.
High‐resolution real‐time spiral MRI for guiding vascular interventions in a rabbit model at 1.5T
Authors: Terashima Masahiro , Hyon MinSu , de la Pena‐Almaguer Erasmo , Yang Phillip C. , Hu Bob S. , Nayak Krishna S. , Pauly John M. , McConnell Michael V. 
Published: October 2005

AbstractPurposeTo study the feasibility of a combined high spatial and temporal resolution real‐time spiral MRI sequence for guiding coronary‐sized vascular interventions.Materials and MethodsEight New Zealand White rabbits (four normal and four with a surgically‐created stenosis in the abdominal aorta) were studied. A real‐time interactive spiral MRI sequence combining 1.1 × 1.1 mm2 in‐plane resolution and 189‐msec total image acquisition time was used to image all phases of an interventional procedure (i.e., guidewire placement, balloon angioplasty, and stenting) in the rabbit aorta using coronary‐sized devices on a 1.5 T MRI system.ResultsReal‐time spiral MRI identified all rabbit aortic stenoses and provided high‐temporal‐resolution visualization of guidewires crossing the stenoses in all animals. Angioplasty balloon dilatation and deployment of coronary‐sized copper stents in the rabbit aorta were also successfully imaged by real‐time spiral MRI.ConclusionCombining high spatial and temporal resolution with spiral MRI allows real‐time MR‐guided vascular intervention using coronary‐sized devices in a rabbit model. This is a promising approach for guiding coronary interventions. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.