bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absence of carboxypeptidase E leads to adult hippocampal neuronal degeneration and memory deficits
Authors: Woronowicz Alicja , Koshimizu Hisatsugu , Chang Su‐Youne , Cawley Niamh X. , Hill Joanna M. , Rodriguiz Ramona M. , Abebe Daniel , Dorfman Caroline , Senatorov Vladimir , Zhou An , Xiong Zhi‐Gang , Wetsel William C. , Loh Y. Peng 
Published: June 2008

AbstractMolecules that govern the formation, integrity, and function of the hippocampus remain an important area of investigation. Here we show that absence of the proneuropeptide processing enzyme, carboxypeptidase E (CPE) in CPE knock‐out (KO) mice had a profound effect on memory, synaptic physiology, and the cytoarchitecture of the hippocampus in these animals. Adult CPE‐KO mice displayed deficits in memory consolidation as revealed by the water‐maze, object preference, and social transmission of food preference tests. These mice also showed no evoked long‐term potentiation. Additionally, CPE‐KO mice at 4 weeks of age and older, but not at 3 weeks of age, exhibited marked degeneration specifically of the pyramidal neurons in the hippocampal CA3 region which normally expresses high levels of CPE. Immunohistochemistry revealed that the neuronal marker, NeuN, was reduced, while the glial marker, GFAP, was increased, characteristic of gliosis in the CA3 area of CPE‐KO mice. Calbindin staining indicated early termination of the mossy fibers before reaching the CA1 region in these mice. Thus, absence of CPE leads to degeneration of the CA3 neurons and perturbation of the cytoarchitecture of the hippocampus. Ex vivo studies showed that overexpression of CPE in cultured hippocampal neurons protected them against H2O2 oxidative‐stress induced cell death. These findings taken together indicate that CPE is essential for the survival of adult hippocampal CA3 neurons to maintain normal cognitive function. Published 2008 Wiley‐Liss, Inc.
Modelling longwave radiation to snow beneath forest canopies using hemispherical photography or linear regression
Authors: Essery Richard , Pomeroy John , Ellis Chad , Link Tim 
Published: June 2008

AbstractForest canopies reduce shortwave radiation and increase longwave radiation reaching the underlying surface, compared with open areas, and thus influence rates at which forest snowpacks melt. The sub‐canopy radiative environment can be highly heterogeneous, with temporal persistence depending on canopy structure and differing for shortwave and longwave fluxes, and this influences the rate at which snow‐free ground emerges during snowmelt. Arrays of radiometers have been used to measure spatial variability in forest radiation, but such instruments are expensive and require regular attention in snowy environments. Hemispherical photography allows rapid collection of canopy structure data, and many software packages have been developed for modelling transmission of shortwave radiation using hemispherical photographs, but modelling of longwave radiation has received much less attention. Results are used here from radiometers located beneath lodgepole pine stands of varying density at the Marmot Creek Research Basin in Alberta, Canada. A simple model using sky view calculated from hemispherical photographs to weight longwave emissions from the canopy, calculated using measured air temperature as a proxy for canopy temperature, and measured above‐canopy longwave radiation is found to give good estimates for spatial averages of sub‐canopy longwave radiation, although standard deviations are generally underestimated. If above‐canopy longwave radiation is parametrized as a function of air temperature and humidity rather than measured, good results are still obtained for daily and longer averages of sub‐canopy longwave radiation. A multiple linear regression model using measurements of above‐canopy shortwave radiation to estimate daytime canopy heating gives better results in comparison with individual radiometers. Copyright © 2008 John Wiley & Sons, Ltd.
Micropatterned surfaces with controlled ligand tethering
Authors: Petrie Timothy A. , Stanley Brandon T. , García Andrés J. 
Published: June 2008

AbstractMicrocontact printing (μ‐CP) is a facile, cost‐effective, and versatile soft‐lithography technique to create two‐dimensional patterns of domains with distinct functionalities that provides a robust platform to generate micropatterned biotechnological arrays and cell culture substrates. Current μ‐CP approaches rely on nonspecific immobilization of biological ligands, either by direct printing or adsorption from solution, onto micropatterned domains surrounded by a nonfouling background. This technique is limited by insufficient control over ligand density. We present a modified μ‐CP protocol involving stamping mixed ratios of carboxyl‐ and tri(ethylene glycol)‐terminated alkanethiols that provides for precise covalent tethering of single or multiple ligands to prescribed micropatterns via standard peptide chemistry. Processing parameters were optimized to identify conditions that control relevant endpoint pattern characteristics. This technique provides a facile method to generate micropatterned arrays with tailorable and controlled presentation of biological ligands for biotechnological applications and analyses of cell–material interactions. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Genome‐wide expression analysis of cells expressing gain of function mutant D374Y‐PCSK9
Authors: Ranheim Trine , Mattingsdal Morten , Lindvall Jessica M. , Holla Øystein L. , Berge Knut Erik , Kulseth Mari Ann , Leren Trond P. 
Published: June 2008

AbstractProprotein convertase subtilisin/kexin type 9 (PCSK9) is a key regulator of serum cholesterol. The possibility that PCSK9 also functions in other pathways needs to be addressed. We have transfected HepG2 cells with mutant D374Y‐PCSK9 or control vector. Gene expression signatures were determined using the Affymetrix GeneChip technology, and the expression pattern of selected genes was confirmed by quantitative real‐time polymerase chain reaction (qRT‐PCR). Data was normalized and analyzed using a model‐based background adjustment for oligonucleotide expression arrays, then filtered based upon expression within treatments group, and subjected to moderated t‐statistics. Five hundred twenty transcripts had altered expression levels between D374Y‐PCSK9 and control vector. Among the 520 probes on our top list, 312 were found to have an assigned Gene Ontology (GO) term, and 96 were found in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Genome‐wide expression profiling revealed that “steroid biosynthesis,” “sterol metabolism,” and “cholesterol biosynthsis” were affected by D374Y‐PCSK9. Also, the GO biological process terms “response to stresss,” “response to virus,” “response to unfolded protein,” and “immune response” were influenced by D374Y‐PCSK9. Our results suggest that D374Y‐PCSK9 results in up‐regulation of genes involved in sterol biosynthesis and down‐regulation of stress‐response genes and specific inflammation pathways. J. Cell. Physiol. 217: 459–467, 2008. © 2008 Wiley‐Liss, Inc.
Horned lizards (Phrynosoma) incapacitate dangerous ant prey with mucus
Authors: Sherbrooke Wade C. , Schwenk Kurt 
Published: June 2008

AbstractHorned lizards (Iguanidae, Phrynosomatinae, Phrynosoma) are morphologically specialized reptiles characterized by squat, tank‐like bodies, short limbs, blunt snouts, spines and cranial horns, among other traits. They are unusual among lizards in the degree to which they specialize on a diet of ants, but exceptional in the number of pugnacious, highly venomous, stinging ants they consume, especially harvester ants (genus Pogonomyrmex). Like other iguanian lizards, they capture insect prey on the tongue, but unlike other lizards, they neither bite nor chew dangerous prey before swallowing. Instead, they employ a unique kinematic pattern in which prey capture, transport and swallowing are combined into a single feeding stage, apparently leaving the mouth, pharynx, esophagus and stomach vulnerable to bites and stings. Nevertheless, horned lizards consume dozens of harvester ants without harm. We show that their derived feeding kinematics are associated with unique, mucus‐secreting pharyngeal papillae that apparently serve to immobilize and incapacitate dangerous ants as they are swallowed by compacting them and binding them in mucus strands. Radially branched esophageal folds provide additional mucus‐secreting surfaces the ants pass through as they are swallowed. Ants extracted from fresh‐killed horned lizard stomachs are curled ventrally into balls and bound in mucus. We conclude that the pharyngeal papillae, in association with a unique form of hyolingual prey transport and swallowing, are horned lizard adaptations related to a diet of dangerous prey. Harvester ant defensive weapons, along with horned lizard adaptations against such weapons, suggest a long‐term, predator–prey, co‐evolutionary arms race between Phrynosoma and Pogonomyrmex. J. Exp. Zool. 309A:447–459, 2008. © 2008 Wiley‐Liss, Inc.
Increasing severity of status asthmaticus in an urban medical intensive care unit
Authors: Elsayegh Dany , Saito Shigeki , Eden Edward , Shapiro Janet 
Published: June 2008

AbstractBACKGROUND:Life‐threatening status asthmaticus (SA) requiring intensive care is a major concern given the rising prevalence of asthma. We examined episodes of SA requiring admission to the medical intensive care unit (MICU) of an urban hospital center.METHODOLOGY:The charts of patients admitted to the MICU of an urban hospital center with a diagnosis of SA during the 5‐year period 2002–2006 were reviewed retrospectively. These results were compared with those of a previously published experience at our institution from 1995 to 1999.RESULTS:The medical records of 84 MICU admissions for SA were reviewed. There were 61 women (5 pregnant). The mean age was 44 years. Use of cigarettes or illicit drugs was found in 51% and 30%, respectively. Mechanical ventilation (MV) was required in 76% of admissions. Noninvasive ventilation was used in 10 patients. Neuromuscular blockade (NMB) was needed in 9% of admissions. The highest average PaCO2 during the first 24 hours was 67 mm Hg. Median duration of MV was 4.4 days. Six patients died, 3 of whom sustained prehospital cardiac arrest. Compared with the patients in the preceding 5‐year period, the more recent patients had greater use of illicit drug and cigarettes. Patients presented with more severe asthma, as reflected by a higher PaCO2 and an increased duration of MV.CONCLUSIONS:During the recent 5‐year period, we found a trend toward increasing severity of SA, as indicated by the degree of respiratory acidosis, need for NMB, and longer duration of MV. Access to medical care and cigarette and illicit drug use remain potential targets of primary intervention. Journal of Hospital Medicine 2008;3:206–211. © 2008 Society of Hospital Medicine.
Management of parapneumonic effusions in pediatrics: Current practice
Authors: McBride Sarah C. 
Published: June 2008

AbstractPneumonia with associated complex pleural disease is a cause of significant morbidity among hospitalized children. The management of this patient population continues to be a challenge and varies even among single institutions. The article presented here reviews the management goals for pediatric patients hospitalized with complex parapneumonic effusions and provides updated summaries of both medical and surgical therapies. Journal of Hospital Medicine 2008;3:263–270. © 2008 Society of Hospital Medicine.
Factors influencing the steroid profile in doping control analysis
Authors: Mareck Ute , Geyer Hans , Opfermann Georg , Thevis Mario , Schänzer Wilhelm 
Published: June 2008

AbstractSteroid profiling is one of the most versatile and informative screening tools for the detection of steroid abuse in sports drug testing. Concentrations and ratios of various endogenously produced steroidal hormones, their precursors and metabolites including testosterone (T), epitestosterone (E), dihydrotestosterone (DHT), androsterone (And), etiocholanolone (Etio), dehydroepiandrosterone (DHEA), 5α‐androstane‐3α,17β‐diol (Adiol), and 5β‐androstane‐3α,17β‐diol (Bdiol) as well as androstenedione, 6α‐OH‐androstenedione, 5β‐androstane‐3α,17α‐diol (17‐epi‐Bdiol), 5α‐androstane‐3α,17α‐diol (17‐epi‐Adiol), 3α,5‐cyclo‐5α‐androstan‐6ß‐ol‐17‐one (3α,5‐cyclo), 5α‐androstanedione (Adion), and 5β‐androstanedione (Bdion) add up to a steroid profile that is highly sensitive to applications of endogenous as well as synthetic anabolic steroids, masking agents, and bacterial activity. Hence, the knowledge of factors that do influence the steroid profile pattern is a central aspect, and pharmaceutical (application of endogenous steroids and various pharmaceutical preparations), technical (hydrolysis, derivatization, matrix), and biological (bacterial activities, enzyme side activities) issues are reviewed. Copyright © 2008 John Wiley & Sons, Ltd.
Resorbable Scaffolds from Three Different Techniques: Electrospun Fabrics, Salt‐Leaching Porous Films, and Smooth Flat Surfaces
Authors: Finne‐Wistrand Anna , Albertsson Ann‐Christine , Kwon Oh Hyeong , Kawazoe Naoki , Chen Guoping , Kang Inn‐Kyu , Hasuda Hirokazu , Gong Jiansheng , Ito Yoshihiro 
Published: June 2008

AbstractNanofibrous scaffolds of poly[(L‐lactide)‐co‐(1,5‐dioxepan‐2‐one)] generated by electrospinning have been compared with porous films obtained by solvent cast/salt leaching and homogeneous films. A comparison between the fibrous materials and the homogeneous solvent‐cast films revealed that the surface of the nanofibers was more hydrophobic and that the nanofibers were degraded more rapidly in the presence of proteinase. It was obvious that the strain‐to‐break was reduced by the nanofiber formation, it decreased from 370% to 130% independent of fiber diameter. These values were however considerably higher than the strain‐to‐break of the solvent‐cast/salt leaching scaffold. In addition, the nanofibrous material accelerated the adhesion and growth of the mesenchymal stem cell compared to the smooth material.magnified image
Characterisation of Thin Composite Films from Hyperbranched Polyphenylene and Thermolabile Hyperbranched Polycarbonate
Authors: Stumpe Katrin , Eichhorn Klaus‐Jochen , Voit Brigitte 
Published: June 2008

AbstractThin composite films made from a thermally stable hyperbranched polyphenylene and a thermolabile hyperbranched polycarbonate were prepared on silicon wafers and characterised. The end groups of the polycarbonate were varied in order to accomplish an optimised interaction between the two components and thus the formation of homogeneous blends. The composite films were annealed at 200 °C in order to decompose the hyperbranched polycarbonate which can act as a porogen. The composition of the films before and after the annealing process was investigated applying IR spectroscopy and spectroscopic ellipsometry. Analysis of the data allowed calculating the volume fractions of the two materials within the films.magnified image
Thermal Behaviour and Glass Transition Dynamics of Inclusion Complexes of α‐Cyclodextrin with Poly(D,L‐lactic acid)
Authors: Mano João F. 
Published: June 2008

AbstractInclusion complexes (ICs) have been prepared by the host–guest interaction between α‐cyclodextrin (αCD) and poly(d,l‐lactic acid) (PDLLA). This enables transformation of the amorphous polymer into a well organized channel‐type crystalline structure, as studied by wide angle X‐ray scattering (WAXS). WAXS experiments using synchrotron radiation allowed the evolution of this crystalline structure to be followed upon heating. The diffraction peaks disappeared above 320 °C, in a temperature region similar to the occurrence of thermal degradation, also investigated by thermogravimetric analysis. No glass transition could be detected in the IC using differential scanning calorimetry (DSC), but non‐conventional dynamic mechanical analysis measurements revealed the existence of loss factor peaks shifted to higher temperatures when compared with PDLLA. The relaxation plot of the IC was characterized by an Arrhenius behaviour with a high activation energy that could be consistent with the high geometrical confinement felt by the chains in the nanostructured organization.magnified image
Degradation Mechanisms of Biodegradable Poly(DL‐lactide‐co‐glycolide)1000 Diacrylate Network as Studied by Proton Solid‐State Flow NMR Relaxometry
Authors: Litvinov V. M. , Plum B. , Boerakker M. , Dias A. A. 
Published: June 2008

AbstractSummary:Degradation mechanisms of biodegradable photo‐polymerised poly(DL‐lactide‐co‐glycolide)1000 diacrylate {[(DL‐LA/GA)DA]} matrices or films were studied by proton solid‐state NMR relaxometry. A flow NMR unit cell was developed for this purpose. The (DL‐LA/GA)DA‐network was degraded in PBS buffer solution of pH = 7.4. A real‐time proton NMR method provided information about the staged break down of the network during continuous circulation of the buffer solution through the NMR tube. The current study shows that degradation of the network proceeds in three stages: 1 ‐ extraction of a sol fraction that causes substantial immobilization of the material, 2 ‐ scissions of network chains producing network defects without formation of extractable products, and 3 – finally, chain scissions that cause formation of a sol fraction and complete degradation of the material. It was shown that the [(DL‐LA/GA)DA‐network was composed of rigid and viscoelastic domains on all stages of degradation. This heterogeneity could be due to heterogeneous spatial distribution of network junctions in the initial network and/or nano‐scale phase separation of polyacrylate chains that form multifunctional network junctions and poly(lactide‐co‐glicolide) network chains. A combination of bulk and surface erosion both on nano‐ and macroscopic scales could explain the observed degradation mechanisms. It is shown that knowledge of weight loss upon hydrolytic degradation is not sufficient for understanding degradation mechanisms in the relation to functional properties of this type of hydrogels.
A new Phosphorylated Polysaccharide for Biomedical Applications: Generation of 3D Scaffolds with Osteogenic Activity and Coating of Titanium Oxide Surfaces
Authors: Pasqui Daniela , Danieli Elisa , Leone Gemma , Torricelli Paola , Barbucci Rolando 
Published: June 2008

AbstractSummary:A new phosphorylated derivative of carboxymethylcellulose and amidic carboxymethylcellulose containing one phosphate group for each disaccharide unit was synthesized using sodium trimetaphospahte (STMP) as the phosphating agent. The new polysaccharide was characterized by infrared spectroscopy (FT‐IR) and the amount of phosphate groups was determined by elemental analysis. These modified polysaccharides were used both to prepare 3D scaffolds and functionalize titanium oxide surfaces with the aim to improve the osseointegration with the host tissue. The presence of phosphate groups modify the physical‐chemical properties of the hydrogels with respect to the native ones. The evaluation of the bioactivity of the phosphorylated carboxymethylcellulose hydrogels towards osteoblast‐like cells showed a significant increase in the osteocalcin production. The modified surfaces were chemically characterized by means of X‐ray photoelectron spectroscopy (XPS) and FT‐IR, whereas the surface topography was analysed by Atomic Force Measurements (AFM) measurements before and after the polysaccharide coating. In vitro biological tests using osteoblast‐like cells demonstrated that phosphorylated carboxymethylcellulose functionalized TiO2 surfaces promoted better cell adhesion and significantly enhanced their proliferation. These findings suggest that the phosphate polysaccharide both as a 3D scaffold and as a surface coating promotes osteoblast growth potentially improving the biomaterial osseointegration rate.
Novel Poly(amidoamine)‐Based Hydrogels as Scaffolds for Tissue Engineering
Authors: Emilitri Elisa , Guizzardi Fabiana , Lenardi Cristina , Suardi Marco , Ranucci Elisabetta , Ferruti Paolo 
Published: June 2008

AbstractSummary:Poly(amidoamine)s are biocompatible biodegradable polymers, which can be easily functionalized with a number of bioactive and biomimetic compounds. Co‐polymerization of these polymers with 4‐aminobutyl guanidine (agmatine) leads to an RGD mimicking structure. Hydrogels based on this structure showed an enhanced cell adhesion and could be chemically linked to a glass substrate to create a bioadhesive support for cell growth. Preliminary optimization and cell adhesion tests on Madin‐Darby Canine Kidney cells were performed, both on functionalized and non‐functionalized structures, with promising results.
Negative Temperature Sensitive Hydrogels in Controlled Drug Delivery
Authors: Geever Luke , Cooney Ciaran , Devine Declan , Devery Sinead , Nugent Michael , Higginbotham Clement 
Published: June 2008

AbstractSummary:PVP/PNIPAAm copolymers exhibit a temperature sensitive nature that makes them an attractive candidate for controlled drug delivery devices. Diclofenac sodium was added to the monomeric mixture, which included an initiator and crosslinking agent (where appropriate), prior to UV photopolymerisation. It was found that the xerogels retained similar properties as the original samples (not containing drug) at lower levels of drug integration. In all cases, drug dissolution analysis showed that the active agent was released at a slower rate at temperatures above the Lower Critical Solution Temperature (LCST). Interestingly, the drug release trends were almost identical for both the physically and chemically crosslinked hydrogels, when the decrease in transition temperature caused by the incorporated crosslinking agent is taken into consideration. It is believed that both types of copolymers reached a constant maximum swollen weight at a set of temperatures above their transition temperatures. When this swollen plateau is attained, the hydrophilic‐hydrophobic interactions are balanced, thus the gel does not swell or shrink further and the drug diffuses out at a constant rate.
Characterisation of Redox Initiators for Producing Poly(Vinyl Alcohol) Hydrogels
Authors: Martens Penny , Grant Michele , Nilasaroya Anastasia , Whitelock John , Poole‐Warren Laura 
Published: June 2008

AbstractSummary:This work focuses on the characterisation of ascorbic acid/persulphate initiating system. Three different persulphates were used (ammonium, potassium and sodium), and a range of initiator concentrations were tested. Gel time, gel quality, initiator toxicity, and cell survival upon encapsulation were measured. No significant differences were observed between the three types of persulphates. Higher concentrations of the initiators resulted in faster gel times (5min for 0.05wt% initiator) and higher quality gels (less than 20% sol fraction), although the lower initiator concentrations were better in terms of cell growth inhibition and survival upon encapsulation. Overall, this system shows great promise for use in biomedical applications, however there is a need to minimise the initiator concentration to increase cell compatibility while maintaining a high enough concentration for adequate gel formation.