bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of pH on the polymer degradation and drug release from PLGA‐mPEG microparticles
Authors: Li Jin , Jiang Guoqiang , Ding Fuxin 
Published: March 2008

AbstractIn vitro drug release and degradation mechanism of Poly (dl‐lactide‐co‐glycolic acid)‐ methoxypoly (ethyleneglycol) (PLGA‐mPEG) microparticles were investigated under different pH conditions. Methotrexate(MTX), an antirheumatic drug, was employed as the model drug. In polyester‐based microparticle system, two main issues involved in degradation were water uptake and the carboxylic groups produced by chain scission. Polymer composition was identified to be responsible for the odd degradation behavior in different releasing media. Because of the exposure of mPEG chains at the particle surface, microparticle degradation showed apparent different mechanism under the investigated releasing conditions. At pH 10.08, microparticles exhibited rapid weight loss but slower molecular weight decrease, and the degradation pattern was close to surface degradation. At pH 7.4, microparticles underwent heterogeneous bulk degradation. However, at pH 1.2, it showed fastest molecular weight decrease while slowest weight loss, and homogeneous degradation was observed. Particle agglomeration was also seen in acidic environment. Fourier transform infrared (FTIR) spectrum results indicated the crystallization of drugs under the low pH condition. Drug release was dependent on transport paths and drug property. These two factors were highly controlled by the polymer degradation and drug solubility in the releasing media as well as drug crystallinity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Poly(urethanes) containing silarylene and/or germarylene units
Authors: Terraza C. A. , Tagle L. H. , Leiva A. , Poblete L. , Concha F. J. 
Published: March 2008

AbstractA series of 10 poly(urethanes) were synthesized by solution polymerization from bis(chloroformates) and aromatic diamines, containing both silicon or germanium as central atom. So, the polymers prepared contain two silicon atoms or two germanium atoms exclusively or combinations of both. Me, Et, and Ph groups were bonded to the central atoms according to the nature of the monomers employed. Poly(urethanes) were characterized by FTIR, 1H, 13C, and 29Si NMR spectroscopy and the results agreed with the proposed structures. Additionally, intrinsic viscosity values were established in DMSO solutions and thermal analyses were developed. In all cases, thermostable oligomers were obtained, which showed a degradation process beginning at ∼240–260°C. Polymers showed a thermal dependence with the nature of the heteroatom employed. Thus, in general, when germanium was used as central atom, the thermal stability was higher than the polymers containing silicon which agrees with the lower polarity and higher energy of the CGe bond in comparison with the CSi one. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.
An exploration of affect factors and their role in user technology acceptance: Mediation and causality
Authors: Sun Heshan , Zhang Ping 
Published: March 2008

AbstractAffect factors have gained researchers' attention in a number of fields. The Information Systems (IS) literature, however, shows some gaps and inconsistencies regarding the role of affect factors in human–computer interaction. Building upon prior research, this study aims at a better understanding of affect factors by clarifying their relationships with each other and with other primary user acceptance factors. Two affect variables that are different in nature were examined: computer playfulness (CP) and perceived enjoyment (PE). We theoretically clarified and methodologically verified their mediating effects and causal relationships with other primary factors influencing user technology acceptance, namely perceived ease of use (PEOU), perceived usefulness (PU), and behavioral intention (BI). Quantitative data were analyzed using R.M. Baron and D. Kenny's (1986) method for mediating effects and P.R. Cohen, A. Carlsson, L. Ballesteros, and R.S. Amant's (1993) path analysis method for causal relationships. These analyses largely supported our hypotheses. Results from this research indicate that a PE → PEOU causal direction is favored, and PEOU partially mediates PE's impacts on PU whereas PE fully mediates CP's impact on PEOU. With the increased interest in various affect factors in user technology acceptance and use, our study sheds light on the role of affect factors from both theoretical and methodological perspectives. Practical implications are discussed as well.
The molecular journey from ductal carcinoma in situ to invasive breast cancer
Authors: Wiechmann Lisa , Kuerer Henry M. 
Published: March 2008

AbstractDuctal carcinoma in situ (DCIS) accounts for approximately 20% of mammographically detected breast cancers. DCIS can recur or progress to invasive breast cancer, but the ability to predict the outcome of patients with DCIS remains limited, leading to inappropriate treatment choices. To the authors' knowledge to date, the hunt for molecular prognostic markers for DCIS has been unsuccessful. Emerging technologies, however, are shedding new light on the biologic course of DCIS. In the current study, the authors review recent findings elucidating the molecular journey from DCIS to invasive cancer and discuss how these findings will lead to more effective treatment with minimization of morbidity. Cancer 2008. © 2008 American Cancer Society.
The association between extent of lymphadenectomy and survival among patients with lymph node metastases undergoing radical cystectomy
Authors: Wright Jonathan L. , Lin Daniel W. , Porter Michael P. 
Published: March 2008

AbstractBACKGROUND.Long‐term survival in patients with lymph node‐positive bladder cancer who undergo cystectomy suggests a therapeutic role for lymphadenectomy. The objective of this study was to describe the association between extent of lymphadenectomy and survival in lymph node‐positive patients who underwent radical cystectomy.METHODS.The cohort consisted of patients from the Surveillance, Epidemiology, and End Results registry with transitional cell carcinoma who underwent cystectomy with lymphadenectomy and had at least 1 positive lymph node and no distant metastases. The Kaplan‐Meier method and multivariate Cox proportional‐hazards regression analyses were used to estimate differences in survival among different lymphadenectomy variables.RESULTS.In total, 1260 patients had at least 1 positive lymph node. A median of 9 lymph nodes were removed (range, 1–48 lymph nodes) with a median of 2 positive lymph nodes (range, 1–18 positive lymph nodes), and the median lymph node density was 22%. In multivariate analysis controlling for patient demographics, tumor classification, and year of diagnosis, the number of positive and total lymph nodes removed remained independent predictors of survival. There was an inverse association between the number of lymph nodes removed and the risk of death for all quartiles. Removal of > 10 lymph nodes was associated with increased overall survival (hazard ratio, 0.52; 95% confidence interval, 0.43–0.64). In addition, with a lymph node density from 0.1% to 12.5% as the referent group, each higher quartile experienced worse survival.CONCLUSIONS.An increased number of lymph nodes removed at the time of cystectomy was associated with improved survival in patients with lymph node‐positive bladder cancer. Improved survival was observed at a lower lymph node density threshold than previously reported. The current findings support performing a more extensive lymphadenectomy at the time of cystectomy. Cancer 2008. © 2008 American Cancer Society.
Rapid activity‐dependent delivery of the neurotrophic protein CPG15 to the axon surface of neurons in intact Xenopus tadpoles
Authors: Cantallops Isabel , Cline Hollis T. 
Published: March 2008

AbstractCPG15 (aka neuritin) is an activity‐induced GPI‐anchored axonal protein that promotes dendritic and axonal growth, and accelerates synaptic maturation in vivo. Here we show that CPG15 is distributed inside axons and on the axon surface. CPG15 is trafficked to and from the axonal surface by membrane depolarization. To assess CPG15 trafficking in vivo, we expressed an ecliptic pHluorin (EP)‐CPG15 fusion protein in optic tectal explants and in retinal ganglion cells of intact Xenopus tadpoles. Depolarization by KCl increased EP‐CPG15 fluorescence on axons. Intraocular kainic acid (KA) injection rapidly increased cell‐surface EP‐CPG15 in retinotectal axons, but coinjection of TTX and KA did not. Consistent with this, we find that intracellular CPG15 is localized to vesicles and endosomes in presynaptic terminals and colocalizes with synaptic vesicle proteins. The results indicate that the delivery of the neurotrophic protein CPG15 to the axon surface can be regulated on a rapid time scale by activity‐dependent mechanisms in vivo. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
The adolescent brain: Insights from functional neuroimaging research
Authors: Ernst Monique , Mueller Sven C. 
Published: March 2008

AbstractWith the development of functional neuroimaging tools, the past two decades have witnessed an explosion of work examining functional brain maps, mostly in the adult brain. Against this backdrop of work in adults, developmental research begins to gather a substantial body of knowledge about brain maturation. The purpose of this review is to present some of these findings from the perspective of functional neuroimaging. First, a brief survey of available neuroimaging techniques (i.e., fMRI, MRS, MEG, PET, SPECT, and infrared techniques) is provided. Next, the key cognitive, emotional, and social changes taking place during adolescence are outlined. The third section gives examples of how these behavioral changes can be understood from a neuroscience perspective. The conclusion places this functional neuroimaging research in relation to clinical and molecular work, and shows how answers will ultimately come from the combined efforts of these disciplines. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Using imaging and genetics in zebrafish to study developing spinal circuits in vivo
Authors: McLean David L. , Fetcho Joseph R. 
Published: March 2008

AbstractImaging and molecular approaches are perfectly suited to young, transparent zebrafish (Danio rerio), where they have allowed novel functional studies of neural circuits and their links to behavior. Here, we review cutting‐edge optical and genetic techniques used to dissect neural circuits in vivo and discuss their application to future studies of developing spinal circuits using living zebrafish. We anticipate that these experiments will reveal general principles governing the assembly of neural circuits that control movements. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Imaging the spatiotemporal organization of neural activity in the developing spinal cord
Authors: O'Donovan Michael J. , Bonnot Agnes , Mentis George Z. , Arai Yoshi , Chub Nikolai , Shneider Neil A. , Wenner Peter 
Published: March 2008

AbstractIn this review, we discuss the use of imaging to visualize the spatiotemporal organization of network activity in the developing spinal cord of the chick embryo and the neonatal mouse. We describe several different methods for loading ion‐ and voltage‐sensitive dyes into spinal neurons and consider the advantages and limitations of each one. We review work in the chick embryo, suggesting that motoneurons play a critical role in the initiation of each cycle of spontaneous network activity and describe how imaging has been used to identify a class of spinal interneuron that appears to be the avian homolog of mammalian Renshaw cells or 1a‐inhibitory interneurons. Imaging of locomotor‐like activity in the neonatal mouse revealed a wave‐like activation of motoneurons during each cycle of discharge. We discuss the significance of this finding and its implications for understanding how locomotor‐like activity is coordinated across different segments of the cord. In the last part of the review, we discuss some of the exciting new prospects for the future. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
In vivo imaging of presynaptic terminals and postsynaptic sites in the mouse submandibular ganglion
Authors: McCann Corey M. , Lichtman Jeff W. 
Published: March 2008

AbstractMuch of what is currently known about the behavior of synapses in vivo has been learned at the mammalian neuromuscular junction, because it is large and accessible and also its postsynaptic acetylcholine receptors (AChRs) are readily labeled with a specific, high‐affinity probe, α‐bungarotoxin (BTX). Neuron–neuron synapses have thus far been much less accessible. We therefore developed techniques for imaging interneuronal synapses in an accessible ganglion in the peripheral nervous system. In the submandibular ganglion, individual preganglionic axons establish large numbers of axo‐somatic synapses with postganglionic neurons. To visualize these sites of synaptic contact, presynaptic axons were imaged by using transgenic mice that express fluorescent protein in preganglionic neurons. The postsynaptic sites were visualized by labeling the acetylcholine receptor (AChR) α7 subunit with fluorescently tagged BTX. We developed in vivo methods to acquire three‐dimensional image stacks of the axons and postsynaptic sites and then follow them over time. The submandibular ganglion is an ideal site to study the formation, elimination, and maintenance of synaptic connections between neurons in vivo. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Management of sinonasal undifferentiated carcinoma
Authors: Tanzler Emily D. , Morris Christopher G. , Orlando Christine A. , Werning John W. , Mendenhall William M. 
Published: March 2008

AbstractBackground.Our aim was to report the outcomes of treatment for sinonasal undifferentiated carcinoma (SNUC).Methods.Between September 1992 and October 2005, 15 patients were treated with curative intent with surgery (n = 1), surgery and adjuvant radiotherapy (n = 9), and definitive radiotherapy (RT) (n = 5). Follow‐up ranged from 11 to 151 months (median, 30); follow‐up on living patients ranged from 12 to 151 months (median, 22). No patient was lost to follow‐up.Results.Seven patients (47%) developed a recurrence from 3 to 50 months (median, 9) after treatment. The 3‐year outcomes were: local control, 78%; locoregional control, 65%; distant metastasis–free survival, 82%; cause‐specific survival, 77%, and survival, 67%. The local control rates versus treatment modality were: surgery, 0/1 (0%); surgery and postoperative RT, 7/7 (100%); preoperative RT and surgery, 2/2 (100%); and definitive RT, 2/5 (40%). One patient (7%) treated with surgery and postoperative RT sustained a fatal complication.Conclusions.Combined surgery and adjuvant RT likely offer the best chance of cure compared with either modality alone. The impact of adjuvant chemotherapy is unclear. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Functional reconstruction of complex lip and cheek defect with free composite anterolateral thigh flap and vascularized fascia
Authors: Kuo Yur‐Ren , Jeng Seng‐Feng , Wei Fu‐Chan , Su Chih‐Ying , Chien Chih‐Yen 
Published: March 2008

AbstractBackground.Extensive composite defects involving the lip and cheek present difficult reconstructive challenges. This study presents a technique using anterolateral thigh (ALT) flaps with vascularized fascia for large complex oral sphincter defect reconstruction.Methods.Fifteen patients who had undergone oral cancer ablation were enrolled in the study. The average area of intraoral lining and cheek–lip skin defects was 96.9 cm2. Upper‐lip defects ranged 0% to 60%, and lower‐lip defects ranged 20% to 80%. Skin and intraoral lining defects were replaced by an ALT fasciacutaneous flap. The vascularized fascia of the flap was used to provide lip suspension.Results.Flap survival was 100%. All but 1 patient had good static suspension. Nine patients had adequate oral competence without drooling, but 6 had occasional oral incontinence. All patients achieved an acceptable appearance.Conclusions.For extensive cheek–lip composite defects, ALT flap together with vascularized fascia has proven to be a useful option for functional reconstruction. © 2008 Wiley Periodicals, Inc. Head Neck 2008
Emerging perspectives in epidermal growth factor receptor targeting in head and neck cancer
Authors: Kim Seungwon , Grandis Jennifer R. , Rinaldo Alessandra , Takes Robert P. , Ferlito Alfio 
Published: March 2008

AbstractThe epidermal growth factor receptor (EGFR) has been shown to be a promising therapeutic target in head and neck cancer. Cetuximab, a monoclonal antibody against EGFR, has been approved in the United States for use with radiotherapy for head and neck squamous cell carcinoma. However, the role of EGFR targeting agents in other therapeutic modalities, such as combined chemoradiotherapy or induction chemotherapy, remains to be defined. Although results from several clinical trials have demonstrated the therapeutic potentials of EGFR targeting agents in these settings, further studies are necessary before definitive conclusions can be made. The concurrent targeting of EGFR along with other pathways important in carcinogenesis may hold significant therapeutic potential. In particular, several clinical trials are studying the effects of combining agents that target the vascular endothelial growth factor with EGFR inhibitors. Last, studies are ongoing to elucidate the predictive and correlative biomarkers in anti‐EGFR therapy to allow for proper patient selection. In the case of cetuximab, these correlative biomarkers may include elements of the immune system in addition to the signal transduction proteins involved in EGFR pathway. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
A conjecture of Borodin and a coloring of Grünbaum
Authors: Rautenbach Dieter 
Published: March 2008

AbstractIn 1976, Borodin conjectured that every planar graph has a 5‐coloring such that the union of every k color classes with 1 ≤ k ≤ 4 induces a (k—1)‐degenerate graph. We prove the existence of such a coloring using 18 colors. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:139–147, 2008
An improved bound for the strong chromatic number
Authors: Haxell P. E. 
Published: March 2008

AbstractLet η > 0 be given. Then there exists d0 = d0(η) such that the following holds. Let G be a finite graph with maximum degree at most d ≥ d0 whose vertex set is partitioned into classes of size α d, where α≥ 11/4 + η. Then there exists a proper coloring of G with αd colors in which each class receives all αd colors. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:148–158, 2008
The black stuff and Konstantin Nikolaevich Tretiakoff
Authors: Lees Andrew J. , Selikhova Marianna , Andrade Luiz Augusto , Duyckaerts Charles 
Published: March 2008

AbstractKonstantin Tretiakoff's doctoral dissertation “Contribution a l'Etude de L'Anatomie pathologique du Locus Niger de Soemmering avec quelques déductions relatives à la pathogénie des troubles du tonus musculaire et De La Maladie de Parkinson” (A Study of the Pathological anatomy of the locus niger of Soemerring and its relevance to the pathogenesis of changes in muscular tone in Parkinson's disease) published in 1919 earned him a silver medal awarded by the University of Paris but failed to gain him the recognition its importance deserved. Despite belated acknowledgment of the importance of his findings Tretiakoff received little acclaim during his life and there have been no biographical accounts written in English or French. Fifty years after his death it seems appropriate to relate some aspects of his interesting peripatetic life and recognize the continuing relevance of his pioneering research on “the black stuff” to our understanding of Parkinson's disease. © 2008 Movement Disorder Society
Oculomotor function in multiple system atrophy: Clinical and laboratory features in 30 patients
Authors: Anderson Tim , Luxon Linda , Quinn Niall , Daniel Susan , David Marsden C. , Bronstein Adolfo 
Published: March 2008

AbstractWe reviewed the clinical and laboratory oculomotor features in 30 patients with probable multiple system atrophy (MSA), 22 with MSA‐P and 8 with MSA‐C. Six patients were also examined post mortem, MSA being confirmed in four and excluded in two (Parkinson's disease and progressive supranuclear palsy). Clinical examination showed the following abnormalities; excessive square wave jerks—21 of 30 patients; mild vertical supranuclear gaze palsy—8 of 30; gaze‐evoked nystagmus—12 of 30 patients, three of whom had no extraocular evidence of cerebellar dysfunction; positioning downbeat nystagmus—10 of 25; mild or moderate saccadic hypometria—22 of 30; impaired (“broken up”) smooth pursuit—28 of 30; reduced VOR suppression—16 of 24. Electro‐oculography and caloric testing did not add significant extra information. In patients presenting with an akinetic‐rigid syndrome it can be difficult to differentiate idiopathic Parkinson's disease from MSA‐P and other causes of atypical parkinsonism. Our findings suggest that the presence of excessive square wave jerks, mild – moderate hypometria of saccades, impaired VOR suppression, spontaneous nystagmus or positioning downbeat nystagmus may be oculomotor “red flags” or clues to the presence of MSA. Further, the presence of clinically slow saccades, or moderate‐to‐severe gaze restriction, suggests a diagnosis other than MSA. © 2008 Movement Disorder Society
Neuronal activity of the red nucleus in Parkinson's disease
Authors: Rodriguez‐Oroz María C. , Rodriguez Manolo , Leiva Carlos , Rodriguez‐Palmero Miguel , Nieto Juan , Garcia‐Garcia David , Luis Zubieta Jose , Cardiel Carlos , Obeso Jose A. 
Published: March 2008

AbstractPrecise placement of the electrodes for stimulation of the subthalamic nucleus (STN) in Parkinson's disease (PD) is crucial for the therapeutic benefit. As a result of the mistargeting and misplacement of the electrodes during surgery in 2 patients with PD, we have characterized the neuronal firing in the red nucleus (RN) and observed the effects of stimulation of this nucleus. Although the neuronal firing (mean ± SD) of the RN (34 ± 4.4 Hz) resembles that described for the STN (33.1 ± 16.6 Hz), a higher proportion of cells responded to the movement of the contralateral limbs (70–80%). Stimulation in the area of the RN‐induced intolerable side effects without motor improvement. We conclude that the STN and RN have some similar neurophysiological features but can be distinguished intraoperatively. This initial description of the physiological characteristics of the RN in humans will draw attention to the possibility of confusing the RN and STN during intraoperative recording. © 2008 Movement Disorder Society