bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrokinetic partial filling technique as a powerful tool for enantiomeric separation of DL‐lactic acid by CE with contactless conductivity detection
Authors: Maier Vítězslav , Petr Jan , Knob Radim , Horáková Jana , Ševčík Juraj 
Published: April 2007

AbstractA modified partial filling method for chiral separation of DL‐lactic acid as the model chiral compound with vancomycin chloride as the chiral selector was developed by CE with contactless conductivity detection. Electrokinetic partial filling technique (EK‐PFT) was used as an alternative method to the conventional hydrodynamic partial filling method. EK‐PFT, in contrast to the hydrodynamic partial filling technique, allowed the removal of the chloride counterions from the chiral selector which otherwise led to poor sensitivity in conductivity detection. The baseline separation of DL‐lactic acid as the model analyte was achieved in 5 min in a polyacrylamide‐coated capillary. The best resolution was achieved by electrokinetic partial filling of vancomycin cations from the injection solution containing 5 mmol/L oxalate L‐histidinium at pH 4.5 with 10 mmol/L vancomycin chloride. Computer simulation was used to explain the observed phenomena in the boundary between the inject vial and the capillary during the EK‐PFT of vancomycin cations.
Major events of Paleogene mammal radiation in China
Authors: Yuanqing Wang , Jin Meng , Xijun Ni , Chuankui Li 
Published: April 2007

AbstractOn the basis of mammalian biostratigraphical study, the Paleogene was subdivided into 11 land mammal ages in China: the Paleocene Shanghuan, Nongshanian and Gashatan; the Eocene Lingchan, Arshantan, Irdinmanhan, Sharamurunian, Naduan and Ulangochuan; and the Oligocene Ulantatalian and Tabenbulukian. Biostratigraphical correlation with North American Land Mammal Ages, plus some palaeomagnetic, isotopic and radiometric results, established the indirect connection with the international time scale. Under this biochronological framework, the compositional change of mammalian faunas and the evolution of major groups are discussed. Three stages are recognized in the Paleogene mammalian radiation: (1) the Paleocene flourishing of archaic groups, (2) the Eocene rising and development of modern major groups and (3) the Oligocene faunal reorganization. During the Paleocene, the mammalian radiation was dominated by the archaic groups and the faunas showed apparent endemism. The radiation was characterized by faunal turnovers due to the flourishing of different families in archaic groups. During this period, ancestral forms of modern glires emerged and the first Rodentiaformes appeared in the late Late Paleocene. Such faunal changes corresponded to the successive rise of temperature after the transition from the Mesozoic to the Cenozoic. The Initial Eocene Thermal Maximum resulted in a significant decrease of the archaic groups and the faunal composition became more similar to that of modern ones. At the beginning of the Eocene, Artiodactyla and Euprimates appeared and Rodentia and Perissodactyla began to differentiate. During the Eocene, Mixodontia, Arctostylopidae, Dinocerata, Pantodonta, Tillodontia and Creodonta disappeared in succession. Perissodactyla became the dominant group in the faunas. The faunal turnovers were characterized by the alteration of dominant families due to the appearance, differentiation and flourishing of families in modern orders. The severe cooling events at the Eocene–Oligocene transition resulted in the development of open grassland, that further contributed to the great mammalian faunal turnover. The perissodactyl‐dominant Eocene faunas were replaced by the rodent/lagomorph‐dominant Oligocene faunas. The appearance and radiation of hypsodont mammal groups characterized the mammalian evolution in the Oligocene. Copyright © 2007 John Wiley & Sons, Ltd.
Advantages of using glycolic acid as a retardant in a brushite forming cement
Authors: Mariño Faleh Tamimi , Torres Jesús , Hamdan Mohammad , Rodríguez Carmen Rueda , Cabarcos Enrique López 
Published: April 2007

AbstractIn this study we have compared the effect of using acetic, glycolic, and citric acids on the brushite cement setting reaction and the properties of the resultant cement. The cement solid phase was made by mixing β‐tricalcium phosphate (β‐TCP), monocalcium dihydrogen phosphate anhydrate (MCPA), and sodium pyrophosphate, whereas the cement liquid phase consisted of aqueous solutions of carboxy acids at concentrations ranging from 0.5 to 3.5M. Cements were prepared by mixing the solid phase with the liquid phase to form a workable paste. The cement setting time was longer for glycolic and citric acids. The best mechanical properties in dry environments were obtained using glycolic and citric acid liquid phases. In a wet environment at 37°C, the cement set with glycolic acid was the strongest one. Brushite cement diametral tensile strength seems to be affected by the calcium‐carboxyl phase produced in the setting reaction. The acceptable setting time and mechanical properties of cements set in glycolic acid solutions are attributed to the additional hydrophilic groups in the carboxylic acid and the low solubility in water of the calcium salt produced in the reaction. Moreover, at high concentrations, carboxylic acids add chemically to the cement matrix becoming reactants themselves. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Repair of the dura mater with processed collagen devices
Authors: Zerris Vasilios A. , James Kenneth S. , Roberts Julie B. , Bell Eugene , Heilman Carl B. 
Published: April 2007

AbstractBackground: We evaluated in a canine duraplasty model how specific differences in device physicomechanical properties, porosity, and crosslinking influenced the biological performance of three processed collagen dural substitutes. Methods: Three collagen dural substitutes were studied: Dura‐Guard, DuraGen, and Durepair. The initial strength, stiffness, and suture retention force were measured using standard mechanical test methods. The relative pore sizes of each device were assessed with a scanning electron microscope. Differential scanning calorimetry was used to measure their respective collagen denaturation temperatures. The biologic response and performance of the materials were evaluated via an acute (1 month) and long‐term (3 and 6 months) canine bilateral duraplasty study. Results: The mechanical properties of Dura‐Guard and Durepair were similar to native dura. We could not quantify the mechanical properties of DuraGen because of its fragile nature. The denaturation temperature of DuraGen and Dura‐Guard differed significantly from that reported for native collagens. The denaturation temperature of Durepair was comparable with the values reported for native collagens. All three materials were tolerated well by the animals. DuraGen did not maintain its structural integrity beyond 1 month. Dura‐Guard and Durepair persisted for 6 months. Durepair was populated by fibroblasts and blood vessels, whereas Dura‐Guard was not. Conclusions: The three dural substitutes tested were found to be safe and effective in healing surgically created defects in the dura mater. Although each of these dura substitutes are composed of collagen, differences in the collagen source and processing influenced device physicomechanical properties, porosity, and the nativity of the collagen polymer. These measured differences influenced device intraoperative handling and installation as well as the post‐operative biological response, where differences in device resorption, cell penetration, vascularization, and collagen remodeling were observed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Acrylic injectable and self‐curing formulations for the local release of bisphosphonates in bone tissue
Authors: Rodríguez‐Lorenzo L. M. , Fernández M. , Parra J. , Vázquez B. , López‐Bravo A. , Román J. San 
Published: April 2007

AbstractTwo bisphosphonates (BPs), namely 1‐hydroxy‐2‐[4‐aminophenyl]ethane‐1,1‐diphosphonic acid (APBP) and 1‐hydroxy‐2‐[3‐indolyl]ethane‐1,1‐diphosphonic acid (IBP), have been synthesized and incorporated to acrylic injectable and self‐curing formulations. Alendronic acid monosodium trihydrated salt (ALN) containing cement was formulated as control. These systems have potential applications in low density hard tissues affected by ailments characterized by a high osteoclastic resorption, i.e. osteoporosis and osteolysis. Values of curing parameters of APBP and IBP were acceptable to obtain pastes with enough fluency to be injected through a biopsy needle into the bone cavity. Working times ranged between 8 and 15 min and maximum temperature was around 50°C. Cured systems stored for a month in synthetic body fluid had compressive strengths between 90 and 96 MPa and modulus between 1.2 and 1.3 GPa, which suggest mechanical stabilization after setting and in the short time. BPs were released in PBS at an initial rate depending on the corresponding chemical structure in the order ALN > APBP > IBP to give final concentrations in PBS of 2.21, 0.44, and 0.19 mol/mL for ALN, APBP, and IBP, respectively. Cytotoxicities of bisphosphonates were evaluated, IC50 values being in the order APBP > ALN > IBP. Absence of cytotoxicity coming from leachables of the cured systems was observed in all cases independently of the BP. An improved cell growth and proliferation for the systems loaded with APBP and IBP compared with that loaded with ALN was observed, as assessed by measuring cell adhesion and proliferation, and total DNA content. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Effects of different magnitudes of cyclic stretch on Na+‐K+‐ATPase in skeletal muscle cells in vitro
Authors: Yuan Xiao , Lin Zhu , Luo Songjiao , Ji Guoping , Yuan Changqing , Wu Yong 
Published: April 2007

AbstractThe Na+‐K+‐ATPase, which plays a major role in modulation of skeletal muscle excitability and contractility, is one of the marker enzymes that senses the mechanical strain and adapts to the stimuli. Although many papers had been published on the effects of mechanical stress on Na+‐K+‐ATPase in aortic smooth muscle cells, little was known about the effects of different magnitudes of mechanical stretch on Na+‐K+‐ATPase in skeletal muscle cells. In the present study, we determined the effect of different magnitudes(6%, 12%, or 25% elongation) of cyclic stretch on the activity of the Na+‐K+‐ATPase and investigated possible mechanisms that might be involved in the action of stretch.The results showed the application of different magnitudes of cyclic stretch induced a magnitude‐dependent increase of Na+‐K+‐ATPase activity in cultured skeletal muscle cells. Furthermore, inhibition of ionic fluxes through SACs prevented the action of stretch on Na+‐K+‐ATPase activity. The stretch‐induced increase in Na+‐K+‐ATPase activity was not blocked by Actinomycin D. No significant changes in mRNA and total cell protein levels of Na+‐K+‐ATPase were detected after stretched continuious for 24 h. However, cyclic stretch increased cell surface expression of Na+‐K+‐ATPase α1‐ and α2‐subunit proteins by 1.3‐ and 1.75‐fold, respectively, and the increases in Na+‐K+‐ATPase activity and cell surface expression were abolished by LY‐294002. These data indicated that cyclic stretch induced a “magnitude‐dependent” increase of Na+‐K+‐ATPase activity in cultured skeletal muscle cells in vitro. The upregulation involved translocation of Na+‐K+‐ATPase α1‐ and α2‐subunits to plasma membrane, not increased gene transcription. These results suggested a novel nontranscriptional mechanism for regulation of Na+‐K+‐ATPase in skeletal muscle cells by cyclic stretch. J. Cell. Physiol. 212: 509–518, 2007. © 2007 Wiley‐Liss, Inc.
Estrogen receptor alpha (ERα) and insulin‐like growth factor I receptor (IGF‐IR) cross‐talk in the gonadotropic αT3‐1 cell line
Authors: Eertmans Frank , Dhooge Willem , De Wever Olivier , Bracke Marc , Comhaire Frank , Kaufman Jean‐Marc 
Published: April 2007

AbstractIn reproductive tissues such as the breast and the uterus, cell proliferation and differentiation is strongly regulated by complex interactions between estrogen receptor α (ERα) and growth factor receptors. In the present study, we investigated the potential occurrence of such cross‐talk in the murine, gonadotropic αT3‐1 cell line, which expresses ERα and the IGF‐I receptor (IGF‐IR). Under estrogen‐free conditions, basal cell proliferation and ER‐mediated gene transcription was strongly inhibited by the selective estrogen receptor modulator (SERM) 4‐hydroxy‐tamoxifen (4‐OH‐Tam) and by the pure anti‐estrogen ICI 182,780 (ICI). These effects can be reversed by either 17‐β‐estradiol (E2) or insulin‐like growth factor I (IGF‐I), both exerting modest mitogenic effects in the αT3‐1 cell line. Furthermore, IGF‐I enhanced both basal and E2‐induced ER‐driven gene transcription. This may be explained, at least in part, by enhanced phosphorylation of ERα at serine 118, a prerequisite for the transactivation capacity of the receptor. Finally, the IGF‐I‐induced response on cell growth and ER‐mediated transactivation can be inhibited with either ICI or 4‐OH‐Tam. In conclusion, our data indicate IGF‐IR and ER interactions in the αT3‐1 cell line, an in vitro model for the pituitary gonadotrophs, hereby suggesting a role of IGF‐I in the regulation of gonadotropin synthesis and secretion. J. Cell. Physiol. 212:583–590, 2007. © 2007 Wiley‐Liss, Inc.
AKT and MAPK signaling in KGF‐treated and UVB‐exposed human epidermal cells
Authors: Lotti Lavinia Vittoria , Rotolo Sabrina , Francescangeli Federica , Frati Luigi , Torrisi Maria Rosaria , Marchese Cinzia 
Published: April 2007

AbstractRegulation of proliferation and differentiation in keratinocyte is a complex and dynamic process that involves activation of multiple signaling pathways triggered by different growth factors. Keratinocyte growth factor (KGF) is not only a potent mitogen, but differently from other growth factors, is a potent inducer of differentiation. The MAP kinase and AKT pathways are involved in proliferation and differentiation of many cell types including keratinocytes. We investigated here the role of KGF in modulating AKT and MAPK activity during differentiation of human keratinocytes. Our results show that the mechanisms of action of KGF are dose‐dependent and that a sustained activation of the MAPK signaling cascade causes a negative regulation of AKT. We also demostrated increasing expression of KGFR substrates, such as PAK4 during keratinocyte differentiation parallel to the receptor upregulation. J. Cell. Physiol. 212:633–642, 2007. © 2007 Wiley‐Liss, Inc.
The immunomodulatory protein SV‐IV protects serum‐deprived cells against apoptosis but not against G0/G1 arrest: Possible implications for the survival of implanting embryo
Authors: Morelli Francesco , Peluso Gianfranco , Petillo Orsolina , Giannattasio Angela , Filosa Silvana , Motta Chiara M. , Tammaro Stefania , Zatterale Adriana , Calzone Rita , Budillon Alfredo , Cartenì Maria , de Maria Salvatore , Costanza Maria R. , Nigro Antonella , Petrazzuolo Marcella , Buommino Elisabetta , Rizzo Maria , Capasso Giovanni , Baiano Salvatore , Moscatiello Francesco , Ravagnan Gianpietro , Fuggetta Maria P. , Tajana Gianfranco , Stiuso Paola , Metafora Bianca M. , Metafora Vittoria , Metafora Salvatore 
Published: April 2007

AbstractSerum deprivation induced in human lymphoblastoid Raji cells oxidative stress‐associated apoptotic death and G0/G1 cell cycle arrest. Addition into culture medium of the immunomodulatory protein Seminal vesicle protein 4 (SV‐IV) protected these cells against apoptosis but not against cycle arrest. The antiapoptotic activity was related to: (1) decrease of endocellular reactive Oxygen species (ROS) (2) increase of mRNAs encoding anti‐oxidant enzymes (catalase, G6PD) and antiapoptotic proteins (survivin, cox‐1, Hsp70, c‐Fos); (3) decrease of mRNAs encoding proapoptotic proteins (c‐myc, Bax, caspase‐3, Apaf‐1). The biochemical changes underlaying these effects were probably induced by a protein tyrosine kinase (PTK) activity triggered by the binding of SV‐IV to its putative plasma membrane receptors. The ineffectiveness of SV‐IV to abrogate the cycle arrest was accounted for by its downregulating effects on D1,3/E G1‐cyclins and CdK2/4 gene expression, ppRb/pRb ratio, and intracellular ROS concentration. In conclusion, these experiments: (1) prove that SV‐IV acts as a cell survival factor; (2) suggest the involvement of a PTK in SV‐IV signaling; (3) point to cell cycle‐linked enzyme inhibition as responsible for cycle arrest; (4) provide a model to dissect the cycle arrest and apoptosis induced by serum withdrawal; (5) imply a possible role of SV‐IV in the survival of hemiallogenic implanting embryos. J. Cell. Physiol. 212:610–625, 2007. © 2007 Wiley‐Liss, Inc.
Prostate carcinoma cells selected by long‐term exposure to reduced oxygen tension show remarkable biochemical plasticity via modulation of superoxide, HIF‐1α levels, and energy metabolism
Authors: Bourdeau‐Heller Jeanne , Oberley Terry D. 
Published: April 2007

AbstractCancer cells are able to tolerate levels of O2 that are damaging or lethal to normal cells; we hypothesize that this tolerance is the result of biochemical plasticity which maintains cellular homeostasis of both energy levels and oxidation state. In order to examine this hypothesis, we used different O2 levels as a selective agent during long‐term culture of DU145 prostate cancer cells to develop three isogenic cell lines that grow in normoxic (4%), hyperoxic (21%), or hypoxic (1%) O2 conditions. Growth characteristics and O2 consumption differed significantly between these cell lines without changes in ATP levels or altered sensitivity to 2‐deoxy‐D‐glucose, an inhibitor of glycolysis. O2 consumption was significantly higher in the hyperoxic line as was the level of endogenous superoxide. The hypoxic cell line regulated the chemical gradient of the proton motive force (PMF) independent of the electrical component without O2‐dependent changes in Hif‐1α levels. In contrast, the normoxic line regulated Hif‐1α without tight regulation of the chemical component of the PMF noted in the hypoxic cell line. From these studies, we conclude that selection of prostate cancer cells by long‐term exposure to low ambient levels of O2 resulted in cells with unique biochemical properties in which energy metabolism, reactive oxygen species (ROS), and HIF‐1α levels are modulated to allow cell survival and growth. Thus, cancer cells exhibit remarkable biochemical plasticity in response to various O2 levels. J. Cell. Physiol. 212:744–752, 2007. © 2007 Wiley‐Liss, Inc.
Ceramide inhibits LPS‐induced production of IL‐5, IL‐10, and IL‐13 from mast cells
Authors: Chiba Norika , Masuda Akio , Yoshikai Yasunobu , Matsuguchi Tetsuya 
Published: April 2007

AbstractMast cells are central regulators of allergic inflammation through production of various chemical mediators and cytokines. Bacterial infection occasionally worsens allergic inflammation. Although the exact mechanism of this phenomenon remains unclear, we have previously reported that LPS stimulates mast cells to produce not only pro‐inflammatory cytokines, such as IL‐6 and TNF‐α, but also Th2‐type cytokines, such as IL‐5 and IL‐13, and a regulatory cytokine, IL‐10. In the present study, we have studied the effect of ceramide on LPS‐mediated cytokine production from mast cells, as ceramide modulates various cellular functions in many cell types. Administration of cell‐permeable C8 ceramide reduced production of IL‐5, IL‐10, and IL‐13 from LPS‐stimulated mouse bone marrow‐derived mast cells (BMMCs) apparently through transcriptional inhibition, but did not affect IL‐6 or TNF‐α production. Consistently, LPS‐stimulated production of IL‐5, IL‐10, and IL‐13 from BMMCs is significantly enhanced in the presence of fumonisin B1, a de novo ceramide synthesis inhibitor. Interestingly, the same C8 ceramide treatment showed opposite effects on cytokine production from LPS‐stimulated macrophages, reducing IL‐6 and TNF‐α while not affecting IL‐10 production. C8 ceramide pretreatment significantly reduced LPS‐induced Akt phosphorylation in BMMCs, but not in macrophages. Furthermore, pretreatment of BMMCs by wortmannin, a specific inhibitor of PI3 kinase, inhibited LPS‐stimulated expression of IL‐5, IL‐10, and IL‐13, but not that of TNF‐α or IL‐6. Thus, ceramide appeared to down‐regulate LPS‐stimulated production of IL‐5, IL‐10, and IL‐13 from mast cells by inhibiting PI3 kinase‐Akt pathway in a cell type‐specific manner. J. Cell. Physiol. 213: 126–136, 2007. © 2007 Wiley‐Liss, Inc.
Fundamentals of viviparity: Comparison of seasonal changes in the uterine epithelium of oviparous and viviparous Lerista bougainvillii (Squamata: Scincidae)
Authors: Adams Susan M. , Biazik Joanna , Stewart Rebecca L. , Murphy Christopher R. , Thompson Michael B. 
Published: April 2007

AbstractDistinct differences in epithelial response between oviparous and viviparous species of skinks led us to investigate morphological differences in the uterus of a species that exhibits bi‐modal reproduction and that may indicate specialities for the different requirements of viviparity and oviparity. The uteri of females from oviparous and viviparous populations of the Australian scincid lizard, Lerista bougainvillii, are described in detail to determine whether the occurrence of uterodomes and the plasma membrane transformation, found in other viviparous species but not oviparous species, are indeed features characteristic of viviparity. Oviductal tissue was dissected at three different stages of reproduction from lizards from both populations: 1) vitellogenic, 2) gravid or pregnant, and 3) non‐reproductive or quiescent. Tissue was observed using both scanning and transmission electron microscopy. Lerista bougainvillii has a simple placental morphology with simple squamous epithelium. In contrast to mammals and other viviparous skinks, L. bougainvillii does not undergo a plasma membrane transformation, but early signs of placentation in viviparous individuals are indicated by changes in the uterine surface that occur largely after embryonic stage 30. There are no obvious cellular differences between the uteri of oviparous and viviparous L. bougainvillii at the non‐reproductive and vitellogenic phase of the reproductive cycle but throughout gestation/gravidity, the cellular differences that could be related to the changing functional requirements with the retention of the viviparous embryo, became apparent. A plasma membrane transformation with ensuing uterodome formation does not occur, which suggests that these more sophisticated changes are a feature of advanced placental development in reptiles. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.