bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the ultrastructure of cortical and retinal terminals in the rat superior colliculus
Authors: Boka Kamran , Chomsung Ranida , Li Jianli , Bickford Martha E. 
Published: July 2006

AbstractWe compared the ultrastructure and synaptic targets of terminals of cortical or retinal origin in the stratum griseum superficiale and stratum opticum of the rat superior colliculus. Following injections of biotinylated dextran amine into cortical area 17, corticotectal axons were labeled by anterograde transport. Corticotectal axons were of relatively small caliber with infrequent small varicosities. At the ultrastructural level, corticotectal terminals were observed to be small profiles (0.44 ± 0.27 μm2) that contained densely packed round vesicles. In tissue stained for gamma amino butyric acid (GABA) using postembedding immunocytochemical techniques, corticotectal terminals were found to contact small (0.51 ± 0.69 μm2) non‐GABAergic dendrites and spines (93%) and a few small GABAergic dendrites (7%). In the same tissue, retinotectal terminals, identified by their distinctive pale mitochondria, were observed to be larger than corticotectal terminals (3.34 ± 1.79 μm2). In comparison to corticotectal terminals, retinotectal terminals contacted larger (1.59 ± 1.70 μm2) non‐GABAergic dendrites and spines (73%) and a larger proportion of GABAergic profiles (27%) of relatively large size (2.17 ± 1.49 μm2), most of which were vesicle‐filled (71%). Our results suggest that cortical and retinal terminals target different dendritic compartments within the neuropil of the superficial layers of the superior colliculus. Anat Rec Part A, 288A:850–858, 2006. © 2006 Wiley‐Liss, Inc.
Regulation of hematopoietic niches by sympathetic innervation
Authors: Aguila Hector Leonardo 
Published: July 2006

AbstractOnce hematopoiesis is established in the bone marrow, a continuous egress of hematopoietic stem cells (HSCs) to the periphery occurs at a low frequency. It has been proposed that this phenomenon is part of a regenerative homeostatic mechanism that ensures the maintenance of hematopoiesis through the life of the individual. The administration of certain cytotoxic drugs or cytokines can enhance the mobilization of hematopoietic progenitors to the periphery. During the past 15 years, granulocyte‐colony stimulating factor (G‐CSF) has been used as a standard cytokine for mobilization protocols in experimental models and in humans. Despite extensive efforts by multiple groups, a definitive mechanism explaining its role in mobilization has not been provided. In a recent paper, Katayama et al.,1 through a series of clever associations supported by well‐defined experimental systems, proposed that signals through the sympathetic nervous system modify the activity of the hematopoietic niche, acting as regulators of the mobilization of hematopoietic progenitors. This surprising finding adds a new level of complexity to the cellular milieu responsible for generation and maintenance of the hematopoietic niche. BioEssays 28: 687–691, 2006. © 2006 Wiley Periodicals, Inc.
Eyeing tumorigenesis: Notch signaling and epigenetic silencing of Rb in Drosophila
Authors: Axelson Håkan 
Published: July 2006

AbstractNotch signaling plays an essential role in the processes of embryogenesis and cellular differentiation, and it is believed that the oncogenic effects of dysregulated Notch signaling are an anomalous reflection of the normal functions of this cascade. Nonetheless, the cellular events associated with oncogenic Notch signaling have thus far remained elusive. In a recent report, Ferres‐Marco et al.1 described how they used the Drosphila eye as a model system and found that elevated Notch signaling in combination with activation of components of the Polycomb complex of transcriptional repressors led to metastatic growth of tumors through epigenetic silencing of the Rbf gene. Rbf is the Drosophila homologue of the retinoblastoma tumor‐suppressor gene (Rb), thus it represents a novel link between Notch signaling, tumor growth and metastasis. BioEssays 28: 692–695, 2006. © 2006 Wiley Periodicals, Inc.
Persistent biases in the amino acid composition of prokaryotic proteins
Authors: Pascal Géraldine , Médigue Claudine , Danchin Antoine 
Published: July 2006

AbstractCorrespondence analysis of 28 proteomes selected to span the entire realm of prokaryotes revealed universal biases in the proteins' amino acid distribution. Integral Inner Membrane Proteins always form an individual cluster, which can then be used to predict protein localisation in unknown proteomes, independently of the organism's biotope or kingdom. Orphan proteins are consistently rich in aromatic residues. Another bias is also ubiquitous: the amino acid composition is driven by the G + C content of the first codon position. An unexpected bias is driven, in many proteomes, by the AAN box of the genetic code, suggesting some functional biochemical relationship between asparagine and lysine. Less‐significant biases are driven by the rare amino acids, cysteine and tryptophan. Some allow identification of species‐specific functions or localisation such as surface or exported proteins. Errors in genome annotations are also revealed by correspondence analysis, making it useful for quality control and correction. BioEssays 28: 726–738, 2006. © 2006 Wiley Periodicals, Inc.
Interaction of Sodium Ions with Cationic Surfactant Interfaces
Authors: Murgia Sergio , Portesani Filippo , Ninham Barry W. , Monduzzi Maura 
Published: July 2006

AbstractThe thermodynamically stable microemulsion and lamellar phases in the didodecyldimethylammonium bromide/water/n‐decane ternary system were explored in the presence of NaBr to gain information on sodium ion–interface interactions. Experimental results, obtained by different NMR techniques, strongly suggest accumulation of sodium ions at the cationic interface. This apparently counterintuitive result is explained by invoking the dispersion potential experienced by the ions near the interface. A mechanism is proposed that can account for the dramatic shrinkage of the microemulsion phase region when an electrolyte is added.
Helix Formation in Synthetic Polymers by Hydrogen Bonding with Native Saccharides in Protic Media
Authors: Waki Minoru , Abe Hajime , Inouye Masahiko 
Published: July 2006

AbstractWater‐soluble poly(m‐ethynylpyridine)s were designed to realize saccharide recognition in protic media. UV/Vis, 1H NMR, and fluorescence measurements revealed that the polymer forms a helical higher order structure by solvophobic interactions between the ethynylpyridine units in the protic medium. The resulting pore in the helix behaves like a binding pocket in proteins, by taking advantage of inwardly directed hydrogen‐bonding functional groups of the polymers. Molecular recognition of native saccharides by the polymers was investigated by circular dichroism (CD). The chirality of the saccharide was transferred to the helical sense of the polymers, accompanied by the appearance of induced CDs (ICDs) in the absorptive region of the polymers. In MeOH/water (10/1), mannose and allose showed intense ICDs, and the apparent association constant between the polymer and D‐mannose was 14 M−1.
Affinity Adhesion of Carbohydrate Particles and Yeast Cells to Boronate‐Containing Polymer Brushes Grafted onto Siliceous Supports
Authors: Ivanov Alexander E. , Panahi Homayon Ahmad , Kuzimenkova Marina V. , Nilsson Lars , Bergenståhl Björn , Waqif Husain S. , Jahanshahi Mohsen , Galaev Igor Yu. , Mattiasson Bo 
Published: July 2006

AbstractCross‐linked agarose particles (Sepharose CL‐6B) and baker's yeast cells were found to adhere to siliceous supports end‐grafted with boronate‐containing copolymers (BCCs) of N,N‐dimethylacrylamide at pH≥7.5, due to boronate interactions with surface carbohydrates of the particles and the cells. These interactions were registered both on macroscopic and on molecular levels: the BCCs spontaneously adsorbed on the agarose gel at pH≥7.5, with adsorption increasing with pH. Agarose particles and yeast cells stained with Procion Red HE‐3B formed stable, monolayer‐like structures at pH 8.0, whereas at pH 7.0–7.8 the structures on the copolymer‐grafted supports were less stable and more random. At pH 9.0, 50 % saturation of the surface with adhering cells was attained in 2 min. Stained cells formed denser and more stable layers on the copolymer‐grafted supports than they did on supports modified with self‐assembled organosilane layers derivatized with low‐molecular‐weight boronate, presumably due to a higher reactivity of the grafted BCCs. Quantitative detachment of adhered particles and cells could be achieved by addition of 20 mM fructose—a strong competitor for binding to boronates—at pH 7.0–9.0. Regeneration of the grafted supports allowed several sequential adhesion and detachment cycles with stained yeast cells. Affinity adhesion of micron‐sized carbohydrate particles to boronate‐containing polymer brushes fixed on solid supports is discussed as a possible model system suggesting a new approach to isolation and separation of living cells.
Improved theory of cyclical electrical field flow fractionation
Authors: Kantak Ameya , Merugu Srinivas , Gale Bruce K. 
Published: July 2006

AbstractPreviously reported theories for cyclical electrical field flow fractionation (CyElFFF) are severely limited in that they do not account for diffusion, steric, or electric double layer effects. Experiments have shown that these theories overpredict the retention of particles in CyElFFF. In this work, we present a model for prediction of steric, diffusion, and electrical effects. The electrical double layer effects are treated using a lumped electrical circuit model that accounts for the field shielding by the electrical double layer formed at the electrode–carrier interface. The electrical effects are shown to dominate retention times and outweigh the contributions of diffusion and particle size. Detailed results from the simulations are presented in this work, and a comparison between the theoretical and experimental results obtained from the retentions of polystyrene particle standards is presented in this paper. The models are shown to correctly predict the retention of the polystyrene standards in CyElFFF with a reasonable error, while existing models are shown to have significant failings.
Transplacental drug transfer and frequency of Tk and Hprt lymphocyte mutants and peripheral blood micronuclei in mice treated transplacentally with zidovudine and lamivudine
Authors: Von Tungeln Linda S. , Williams Lee D. , Doerge Daniel R. , Shaddock Joseph G. , McGarrity Lynda J. , Morris Suzanne M. , Mittelstaedt Roberta A. , Heflich Robert H. , Beland Frederick A. 
Published: July 2006

AbstractIn previous studies, we have shown that zidovudine (3′‐azido‐3′‐deoxythymidine; AZT), but not lamivudine [(‐)2′,3′‐dideoxy‐3′‐thiacytidine; 3TC], is genotoxic when administered to neonatal mice, and that 3TC when coadministered with AZT does not alter the responses observed with AZT alone (Von Tungeln et al. [2002] Carcinogenesis 23:1427–1432). We now have investigated the transplacental transfer of these drugs and the induction of mutants and micronuclei in the neonatal offspring. From gestational day 12 until parturition, female C57BL/6N and C57BL/6N/Tk+/− mice, which had been mated to male C3H/HeNMTV mice, were treated daily by gavage with AZT, 3TC, or a combination of AZT and 3TC. In both dams and fetuses, AZT was found at much higher levels than its metabolites, AZT 5′‐glucuronide and 3′‐azido‐3′‐deoxythymidine. In the neonates, AZT and the mixture of AZT and 3TC caused a decrease in the percentage of reticulocytes (RETs) and an increase in the percentage of micronucleated RETs and micronucleated normochromatic erythrocytes. When assessed 3 weeks after birth, AZT and the combination of AZT and 3TC increased the thymidine kinase (Tk) mutant frequency in male mice; at 5 weeks, 3TC increased the Tk mutant frequency in female mice. The increase in Tk mutants in mice treated with AZT and the mixture of AZT and 3TC was associated with loss of the wild‐type (Tk+) allele (loss of heterozygosity; LOH) and a pattern of discontinuous LOH. These data indicate that AZT, 3TC, and the combination of AZT and 3TC are transplacental mutagens and that the increase in mutants resulting from AZT is due mainly to large‐scale genetic alterations. Environ. Mol. Mutagen. 47:, 2006. Published 2006 Wiley‐Liss, Inc.
Bioactive glass nanofiber–collagen nanocomposite as a novel bone regeneration matrix
Authors: Kim Hae‐Won , Song Ju‐Ha , Kim Hyoun‐Ee 
Published: July 2006

AbstractNanoscale organized organic–inorganic nanocomposite systems have great potential in the development of biomaterials with advanced properties. Herein, we developed a novel nanocomposite biomaterial consisting of bioactive glass nanofiber (BGNF) and collagen reconstituted fibrous matrix for bone regenerative medicine. A sol–gel derived glass with a bioactive composition (58SiO2· 38CaO·4P2O5) was electrospun to a nanoscale fiber with an average diameter of ∼320 nm. The BGNF was subsequently hybridized with type I collagen, which is the main organic constituent of bone matrix. The BGNF and self‐assembled collagen sol were combined in aqueous solution, and then crosslinked to produce a BGNF‐collagen nanocomposite, in the form of either a thin membrane or a macroporous scaffold, by adopting appropriate processing conditions. The BGNF was observed to be distributed uniformly within the collagen reconstituted nanofibrous matrix. The nanocomposite matrices induced rapid formation of bone‐like apatite minerals on their surfaces when incubated in a simulated body fluid, exhibiting excellent bioactivity in vitro. Osteoblastic cells showed favorable growth on the BGNF‐collagen nanocomposite. In particular, the alkaline phosphatase activity of the cells on the nanocomposite was significantly higher than that on the collagen. This novel BGNF‐collagen nanocomposite is believed to have significant potential in bone regeneration and tissue engineering applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Tissue‐engineered tear secretory system: Functional lacrimal gland acinar cells cultured on matrix protein‐coated substrata
Authors: Selvam Shivaram , Thomas Padmaja B. , Trousdale Melvin D. , Stevenson Douglas , Schechter Joel E. , Mircheff Austin K. , Jacob Jean T. , Smith Ronald E. , Yiu Samuel C. 
Published: July 2006

AbstractDry eye is a general term that refers to a myriad of ophthalmic disorders resulting in the inadequate wetting of the corneal surface by the tear film. Dry eyes are typically treated by the application of artificial tears. However, patients with lacrimal insufficiencies such as Stevens‐Johnson syndrome, chemical and thermal injuries, or ocular cicatricial pemphigoid have very limited options because of the short duration and action of lubricating agents. As a therapeutic strategy, we are working to develop a bioengineered tear secretory system for such patients. This article describes the growth and physiological properties of purified rabbit lacrimal gland acinar cells (pLGACs) on several matrix protein‐coated polymers such as silicone, collagen I, copolymers of poly‐D,L‐lactide‐co‐glycolide (PLGA; 85:15 and 50:50), poly‐L‐lactic acid (PLLA), and Thermanox® plastic cell culture coverslips. Monolayers of acinar cells were established on all of the polymeric substrata. An assay of β‐hexosaminidase activity in the supernatant medium showed significant increases in protein secretion, following stimulation with 100 μM carbachol on matrix protein‐coated and uncoated polymers such as silicone, PLGA 85:15, and PLLA. Our study demonstrates that PLLA supported the morphological and physiological properties of purified rabbit lacrimal gland epithelial cells more successfully than the others. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Potential of FeAlCr intermetallics reinforced with nanoparticles as new biomaterials for medical devices
Authors: González‐Carrasco J. L. , Ciapetti G. , Montealegre M. A. , Savarino L. , Muñoz‐Morris M. A. , Baldini N. 
Published: July 2006

AbstractNovel FeAlCr oxide dispersion strengthened intermetallics that are processed by powder metallurgy have been developed as potential biomaterials. The alloys exhibit a small grain size and a fine dispersion of yttria provides the material with a high yield strength and depending on the alloy composition good ductility (up to 5%). The biocompatibility of the alloy was assessed in comparison with commercial alumina. Saos‐2 osteoblast‐like cells were either challenged with mechanically alloyed particles, or seeded onto solid samples. Viability and proliferation of cells were substantially unaffected by the presence of a high concentration of particles (1 mg/mL). Solid samples of novel FeAlCr intermetallic have shown a good biocompatibility in vitro, often approaching the behavior of materials well known for their biological acceptance (e.g. alumina). It has been found that osteoblasts are able to produce ALP, a specific marker of cells with bone‐forming activity. In this respect, ALUSI alloys hold the promise to be suitable substrate for bone integration. The finding of no cytotoxic effect in the presence of the alloy particles is a reliable proof of the absence of acute toxicity of the material. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Bacterial inactivation using a low‐temperature atmospheric plasma brush sustained with argon gas
Authors: Yu Q. S. , Huang C. , Hsieh F.‐H. , Huff H. , Duan Yixiang 
Published: July 2006

AbstractThis study investigated the bacterial inactivation/sterilization effects of a new atmospheric plasma source, which is a brush‐shaped argon glow discharge created under 1 atm pressure. Such an atmospheric plasma brush requires extremely low power of less than 20 W to operate; and therefore is essentially a low‐temperature discharge as confirmed by gas‐phase temperature measurements. Two bacteria,Escherichia coli(E. coli) andMicrococcus luteus(M. luteus), seeded in various media were subjected to plasma treatment and their survivability was examined. It was found that such argon atmospheric plasma brush is very effective in destruction of the bacteria cells. With nutrient broth and standard methods agar as supporting media, a cell reduction in a level of 6 orders of magnitude was observed forE. coliwithin 3–4 min plasma treatment. A similar level of cell reduction was also observed forM. luteusin the two media with 2 or 3 min plasma treatment. The plasma treatment effects on the bacteria cell structures were also examined using scanning electron microscopy and the cell structure damages due to the plasma exposure were observed on both bacteria. The possible sterilization mechanism of the argon plasmas is also discussed in this article. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18‐month follow‐up study
Authors: Kang Sun‐Woong , Cho Eui Ri , Jeon Oju , Kim Byung‐Soo 
Published: July 2006

AbstractThe injection of bulking substances has been proposed as a new therapy to treat urinary incontinence and vesicoureteral reflux. Our previous study demonstrated that poly(lactic‐co‐glycolic acid) (PLGA) microspheres have the potential to serve as a bulking agent for urological injection therapies. Hybrid tissues exhibiting a bulking effect were formed in vivo by PLGA microsphere injection, but long‐term volume stability was not proven. In this study, we hypothesized that the biodegradation rate of the bulking substance (polymer microspheres) would affect the duration of volume conservation of the induced hybrid tissue. To test this hypothesis, rapidly degrading 75:25 PLGA microspheres and slowly degrading poly(L‐lactic acid) (PLLA) microspheres were used as injectable bulking agents for the injection therapy. In vitro degradation tests showed that the mass losses of PLLA and PLGA were 16 and 96% of the initial masses, respectively, at 30 weeks. PLLA and PLGA microspheres were injected into the subcutaneous dorsum of mice. Both types of microspheres were easily injectable through 24‐gauge needles. Histological examinations at various time points indicated that host cells from the surrounding tissues migrated to the spaces between both types of injected microspheres and formed new hybrid tissue structures. Lymphocyte migration was noted around the implanted PLGA and PLLA microspheres, but the inflammatory reaction diminished with time. Importantly, the volume of the PLLA hybrid tissues slowly decreased to 52% of the initial volume at 12 months and maintained that volume until 18 months, whereas the volume of the PLGA hybrid tissues rapidly decreased to 22% at 6 months, and the PLGA hybrid tissues disappeared at 11 months. These results show that the biodegradation rate of the bulking substance may be useful for controlling the duration of volume conservation of the induced hybrid tissue. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Formation of bone‐like apatite enhanced by hydrolysis of octacalcium phosphate crystals deposited in collagen matrix
Authors: Honda Y. , Kamakura S. , Sasaki K. , Suzuki O. 
Published: July 2006

AbstractIt has been shown that granules of synthetic octacalcium phosphate (OCP) or the composites with collagen are capable of enhancing bone regeneration, accompanied by a gradual conversion from OCP to apatite with time. The present study was designed to investigate whether formation of bone‐like apatite can be accelerated by OCP deposited throughout collagen matrix (OCP collagen complex, OCC) immersed in simulated body fluid (SBF). The formation of bone‐like apatite has been suggested to be essential to induce osteoconductivity of various substrates. The formation of OCP in collagen solution was investigated in calcium or phosphate ions in the range between 22.5 and 142.5 mM and pH 6.26 and 8.56. X‐ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) showed that condition to nucleate OCP was limited to that of a solution with Ca/P 0.43 around pH 7.16 in the presence of collagen. OCP was shown to be formed throughout the collagen matrix by SEM observation. The immersion of OCC in SBF up to 10 days enhanced apatite crystal deposition, probably through OCP–apatite conversion: the apatite formation in OCC took place within only 1 day. The present study indicated that the existence of OCP deposited throughout the collagen matrix promotes bone‐like apatite formation under physiological condition. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Biocompatibility of a new radiopaque iodine‐containing acrylic bone cement
Authors: van Hooy‐Corstjens Catharina S. J. , Bulstra Sjoerd K. , Knetsch Menno L. W. , Geusens Piet , Kuijer Roel , Koole Leo H. 
Published: July 2006

AbstractRadiopacity in the vast majority of the commercially available acrylic bone cements that are used clinically is provided by particles of either BaSO4 or ZrO2. Literature reports have shown these agents to have a detrimental effect on some mechanical properties of the cements as well as on its biological response. We, therefore, have developed a new type of bone cement, for which radiopacity results from the presence of an iodine‐containing methacrylic copolymer. The focus of the present work was the comparison of the biocompatibility of this new cement and a commercially available cement that contains barium sulfate. In vitro experiments show that both cements are cytocompatible materials, for which no toxic leachables are found. Implantation of the cements in a rabbit for three months resulted in the occasional presence of a thin fibrous tissue at the cement–bone interface, which is common for acrylic bone cements. Consideration of all the results led to the conclusion that the new cement is as biocompatible as the BaSO4‐containing one. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007