bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurofibromin‐deficient Schwann cells have increased lysophosphatidic acid dependent survival and migration—implications for increased neurofibroma formation during pregnancy
Authors: Nebesio Todd D. , Ming Wenyu , Chen Shi , Clegg Travis , Yuan Jin , Yang Yanzhu , Estwick Selina A. , Li Yan , Li Xiaohong , Hingtgen Cynthia M. , Yang Feng‐Chun 
Published: January 2007

AbstractNeurofibromas are the clinical hallmark of neurofibromatosis Type 1 (NF1), a genetic disorder caused by mutations of the NF1 tumor suppressor gene, which encodes neurofibromin that functions as a GTPase activating protein (GAP) for Ras. During pregnancy, up to 50% of existing neurofibromas enlarge and as many as 60% of new neurofibromas appear for the first time. Lysophosphatidic acid (LPA) is a prototypic lysophospholipid that modulates cell migration and survival of Schwann cells (SCs) and is made in increasing concentrations throughout pregnancy. We addressed the influence of LPA on the biochemical and cellular functions of SCs with a homozygous mutation of the murine homologue of the NF1 gene (Nf1−/−). LPA promoted F‐actin polymerization and increased migration and survival of Nf1−/− SCs as compared to wild type (WT) SCs. Furthermore, LPA induced a higher level of Ras‐GTP and Akt phosphorylation in Nf1−/− SCs as compared to WT cells. Pharmacologic inhibition or siRNA for the p85β regulatory subunit of Class I A PI3‐K significantly reduced LPA‐induced Schwann cell survival and migration. Introduction of NF1‐GRD reconstitution was sufficient to normalize the LPA‐mediated motility of Nf1−/− SCs. As LPA modulates excessive cell survival and motility of Nf1−/− SCs, which are the tumorigenic cells in NF1, targeting PI3‐K may be a potential therapeutic approach in diminishing the development and progression of neurofibromas in pregnant women with NF1. © 2007 Wiley‐Liss, Inc.
Do pre‐irradiation dental extractions reduce the risk of osteoradionecrosis of the mandible?
Authors: Chang Daniel T. , Sandow Pamela R. , Morris Christopher G. , Hollander Rachel , Scarborough Lauren , Amdur Robert J. , Mendenhall William M. 
Published: January 2007

AbstractBackground.This study was done to determine if pre‐radiotherapy (pre‐RT) dental extractions reduce the risk of osteoradionecrosis (ORN).Methods.Between 1987 and 2004, 413 patients with oropharyngeal carcinomas were treated with definitive RT at the University of Florida. Dentate patients underwent pretreatment dental evaluation. Teeth in the RT field were usually extracted if thought to have poor long‐term prognosis from dental disease. The endpoint was ≥grade 2 ORN using a modified staging system. Patients were excluded for local recurrence, additional RT above the clavicles, or head and neck surgery besides neck dissection.Results.ORN rates were as follows: edentulous, <1%; teeth in‐field with pre‐RT extractions, 15%; and teeth in‐field without pre‐RT extractions, 9%. Patients with poor in‐field teeth and pre‐RT extractions had a higher 5‐year incidence of ORN than those who did not have pre‐RT extractions (16% vs 6%, p = .48). Likewise, for those with in‐field teeth in good condition and pre‐RT extractions, the 5‐year ORN incidence was higher than for those who did not undergo extractions (15% vs 2%, p = .42). Multivariate analysis revealed increased ORN risk with doses of >70 Gy, once‐daily fractionation, or brachytherapy.Conclusion.Pre‐RT extractions do not appear to reduce the risk of ORN. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Management of frey syndrome
Authors: de Bree Remco , van der Waal Isaäc , Leemans C. René 
Published: January 2007

AbstractAlmost all patients who undergo parotidectomy will to some extent develop Frey syndrome (auriculotemporal syndrome or gustatory sweating) after surgery, because of aberrant regeneration of cut parasympathetic fibers between otic ganglion and subcutaneous vessels. However, only the minority of these patients needs treatment. The syndrome consists of gustatory sweating, flushing, and warming over the preauricular and temporal areas. Thick skin flap and partial superficial parotidectomy are the most important techniques to minimize the risk of developing symptomatic Frey syndrome. Intracutaneous injection of botulinum toxin A is an effective, long‐lasting, and well‐tolerated treatment of Frey syndrome. If recurrence occurs, the treatment can be repeated. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Current topics in the epidemiology of oral cavity and oropharyngeal cancers
Authors: Gillison Maura L. 
Published: January 2007

AbstractOral cancer incidence rates rose dramatically during the twentieth century in the United States and Europe, especially among individuals under the age of 60 years. Although influenced by age, sex, and country of origin, incidence trends were most strongly affected by elevated risk among individuals born after approximately 1915. This cohort effect was indicative of strong behavioral influences on oral cancer risk. In this article, associations between oral cancer risk and established behavioral risk factors including alcohol and tobacco use are reviewed. Additionally, possible associations between oral cancer risk and oral hygiene, diet, nutritional status, and sexual behavior as well as the influence of genetic factors on oral cancer risk are considered. Special emphasis is placed on evaluating possible risk differences in individuals above and below the age of 45 and in users and nonusers of alcohol and tobacco. © 2007 Wiley Periodicals, Inc. Head Neck 29, 2007
Cutaneous head and neck squamous cell carcinoma metastatic to parotid and cervical lymph nodes
Authors: Veness Michael J. , Porceddu Sandro , Palme Carsten E. , Morgan Gary J. 
Published: January 2007

AbstractNonmelanoma skin cancers occur at an epidemic rate in Australia and are increasing in incidence worldwide. In most patients, local treatment is curative. However, a subset of patients will be diagnosed with a high‐risk cutaneous squamous cell carcinoma (SCC) and are defined as patients at increased risk of developing metastases to regional lymph nodes. Patients with high‐risk SCC may be identified based on primary lesion and patient factors. Most cutaneous SCC arises on the sun‐exposed head and neck. The parotid and upper cervical nodes are common sites for the development of metastases arising from ear, anterior scalp, temple/forehead, or scalp SCC. The mortality and morbidity associated with high‐risk cutaneous SCC is usually a consequence of uncontrolled metastatic nodal disease and, to a lesser extent, distant metastases. Patients with operable nodal disease have traditionally been recommended for surgery. The efficacy of adjuvant radiotherapy has previously been questioned based on weak evidence in the early literature. Recent evidence from larger studies has, however, strengthened the case for adjuvant radiotherapy as a means to improve locoregional control and survival. Despite this, many patients still experience relapse and die. Research aimed at improving outcome such as a randomized trial incorporating the addition of chemotherapy to adjuvant radiotherapy is currently in progress in Australia and New Zealand. Ongoing research also includes the development of a proposed new staging system and investigating the role of molecular factors such as the epidermal growth factor receptor. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Effects of radiotherapy with or without chemotherapy on tongue strength and swallowing in patients with oral cancer
Authors: Lazarus Cathy , Logemann Jeri A. , Pauloski Barbara Roa , Rademaker Alfred W. , Helenowski Irene B. , Vonesh Edward F. , MacCracken Ellen , Mittal Bharat B. , Vokes Everett E. , Haraf Daniel J. 
Published: January 2007

AbstractBackground.Oral tongue strength and swallowing ability are reduced in patients treated with chemoradiotherapy for oral and oropharyngeal cancer.Methods.Patients with oral or oropharyngeal cancer treated with high‐dose chemoradiotherapy underwent tongue strength, swallowing, and dietary assessments at pretreatment and 1, 3, 6, and 12 months posttreatment. Tongue strength was assessed using the Iowa Oral Performance Instrument (IOPI). Oral and pharyngeal residue was evaluated utilizing videofluoroscopy.Results.Mean maximum tongue strength dropped a nonsignificant amount immediately after treatment, and then increased significantly at 6‐ and 12‐months posttreatment completion. Analyses were adjusted for patient dropout. Tongue strength was not significantly correlated with swallow observations of percentage oral and pharyngeal residue. Ability to eat various diet consistencies was reduced after treatment but improved over time at a rate similar to changes in oral intake and type of diet.Conclusions.Parallel but not significant changes in oral intake, diet, and tongue strength in the first year post chemoradiation therapy need further study in a larger population. © 2007 Wiley Periodicals, Inc. Head Neck, 2007
Phosphocholine as a biomarker of breast cancer: Molecular and biochemical studies
Authors: Eliyahu Galit , Kreizman Tamar , Degani Hadassa 
Published: January 2007

AbstractThe discovery of metabolic and molecular markers that help improving the detection and diagnosis of breast cancer is an important goal to be achieved. A high composite‐choline signal in magnetic resonance spectra of breast lesions has been demonstrated to improve the accuracy of breast cancer diagnosis. In the present study we revealed the principal molecular and biochemical steps associated with the induction of choline metabolism and phosphocholine accumulation in human breast cancer cell‐lines in comparison with normal human mammary epithelial cells. We found upregulation of the expression levels of specific choline transporters: organic cation transporter‐2 and choline high affinity transporter‐1, as well as of the enzyme choline kinase α in the cancerous cells in comparison with that in the normal mammary epithelial cells. The expression levels of choline transporter like‐1, organic cation transporter‐1 and choline kinase β were similar in normal and cancerous cells. We further showed that choline transport rates and choline kinase activity indeed increased by several fold in the cancer cells leading to the elevation of phosphocholine. The results strongly suggest that phosphocholine can serve as a biomarker of breast cancer reflecting upregulation of specific choline transporters and choline kinase genes. © 2007 Wiley‐Liss, Inc.
Gene expression profiling of esophageal cancer: Comparative analysis of Barrett's esophagus, adenocarcinoma, and squamous cell carcinoma
Authors: Greenawalt Danielle M. , Duong Cuong , Smyth Gordon K. , Ciavarella Marianne L. , Thompson Natalie J. , Tiang Thomas , Murray William K. , Thomas Robert J.S. , Phillips Wayne A. 
Published: January 2007

AbstractEsophageal cancer is a particularly aggressive tumor with poor prognosis, however, our current knowledge of the genes and pathways involved in tumorigenesis of the esophagus are limited. To obtain insight into the molecular processes underlying tumorigenesis of the esophagus, we have used cDNA microarrays to compare the gene expression profiles of 128 tissue samples representing the major histological subtypes of esophageal cancer (squamous cell carcinoma and adenocarcinoma (ADC)) as well as Barrett's esophagus (BE), the precursor lesion to ADC, and normal esophageal epithelium. Linear discriminant analysis and unsupervised hierarchical clustering show the separation of samples into 4 distinct groups consistent with their histological subtype. Differentially expressed genes were identified between each of the tissue types. Comparison of gene ontologies and gene expression profiles identified gene profiles specific to esophageal cancer, as well as BE. “Esophageal cancer clusters,” representing proliferation, immune response, and extracellular matrix genes were identified, as well as digestion, hydrolase, and transcription factor clusters specific to the columnar phenotype observed during BE and esophageal ADC. These clusters provide valuable insight into the molecular and functional differences between normal esophageal epithelium, BE, and the 2 histologically distinct forms of esophageal cancers. Our thorough, unbiased analysis provides a rich source of data for further studies into the molecular basis of tumorigenesis of the esophagus, as well as identification of potential biomarkers for early detection of progression. © 2007 Wiley‐Liss, Inc.
Development of a new calcium sulphate‐based composite using alginate and chemically modified chitosan for bone regeneration
Authors: Gomez d'Ayala Giovanna , De Rosa Alfredo , Laurienzo Paola , Malinconico Mario 
Published: January 2007

AbstractIn this work we developed a novel calcium sulphate‐based composite in which the hemihydrate calcium sulphate (CHS) can be encapsulated in a polymeric biodegradable and biocompatible matrix, in order to retain the structural integrity and decrease the bioresorption rate in bone regeneration applications. Two polymers were employed to realize this system: chitosan (Ch) and sodium alginate (Alg), both already widely used in biotechnological and biomedical applications. Chitosan was modified in order to obtain a water soluble polymer, the N‐succinylchitosan (sCh). The reaction was performed with succinic anhydride in presence of pyridine and confirmed by FT‐IR and NMR analyses. Finely ground Alg and sCh powders were mixed in different compositions with CHS and by adding water to the powder mixture it was obtained a mouldable paste that sets in few hours. Thermogravimetric analyses coupled with solvent extraction performed on the composite proved the alginate crosslinking in the presence of CHS. Mechanical studies carried out on composites of different compositions demonstrated that the blend of the two polymeric components causes a substantial synergistic reinforcement of composites. The presence of carboxylic groups on sCh chain in addition to those of alginate could enhance the chelating power of polysaccharide mixture. The results obtained with morphological analyses (SEM) further confirmed the hypotesis of the synergistic effect between alginate and N‐succinylchitosan in presence of calcium sulphate. In vitro cytotoxicity tests proved that the developed system was not cytotoxic. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Histological and mechanical evaluation of self‐setting calcium phosphate cements in a sheep vertebral bone void model
Authors: Kobayashi Naomi , Ong Kevin , Villarraga Marta , Schwardt Jeffrey , Wenz Robert , Togawa Daisuke , Fujishiro Takaaki , Turner A. Simon , Seim Howard B. , Bauer Thomas W. 
Published: January 2007

AbstractWe investigated the histological and compressive properties of three different calcium phosphate cements (CPCs) using a sheep vertebral bone void model. One of the CPCs contained barium sulfate to enhance its radiopacity. Bone voids were surgically created in the lumbar region of 23 ovine spines—L3, L4, and L5 (n = 69 total vertebral bodies)—and the voids were filled with one of the three CPCs. A fourth group consisted of whole intact vertebrae. Histologic evaluation was performed for 30 of the 69 vertebrae 2 or 4 months after surgery along with radiographic evaluation. Compressive testing was performed on 39 vertebrae 4 months after surgery along with micro‐CT analysis. All three CPCs were biocompatible and extremely osteoconductive. Osteoclasts associated with adjacent bone formation suggest that each cement can undergo slow resorption and replacement by bone and bone marrow. Compressive testing did not reveal a significant difference in the ultimate strength, ultimate strain, and structural modulus, among the three CPCs and intact whole vertebrae. Micro‐CT analysis revealed good osseointegration between all three CPCs and adjacent bone. The barium sulfate did not affect the CPCs biocompatibility or mechanical properties. These results suggest that CPC might be a good alternative to polymethylmethacrylate for selected indications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Relationship between bone ingrowth, mineral apposition rate, and osteoblast activity
Authors: Bloebaum R.D. , Willie B.M. , Mitchell B.S. , Hofmann A.A. 
Published: January 2007

AbstractTo better understand skeletal attachment of porous coated total hip and knee implants over time, this study investigated the dynamics of osteoblast populations at the interface of porous coated implants in a weight‐bearing ovine model. The relationship between cancellous bone ingrowth, mineral apposition rate (MAR), and osteoblast activity indicators such as osteoblast area, relative osteoblast number, osteoid width, and osteoid area (O.Ar.) were investigated. The data demonstrated that the percent O.Ar. was a marginally significant predictor of bone ingrowth and MAR over time, suggesting that the amount of osteoid present influenced bone ingrowth and MAR in the porous coated implants. The data also demonstrated that all osteoblast activity indicators were significantly greater in the porous coated region compared to the host bone region, while controlling for in situ time (p < 0.05). This may have been due to the trauma of implantation or the influence of the implant load on the bone tissue promoting a regional acceleratory phenomenon. The localized response suggests that specific therapies may be developed to affect the physiology of osteoblasts at the interface of implants, which may allow for improve skeletal attachment of biomaterials and clinical outcomes of cementless joint replacements. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Vascular endothelial growth factor and dexamethasone release from nonfouling sensor coatings affect the foreign body response
Authors: Norton L.W. , Koschwanez H.E. , Wisniewski N.A. , Klitzman B. , Reichert W.M. 
Published: January 2007

AbstractVascular endothelial growth factor (VEGF) and dexamethasone (DX) release from hydrogel coatings were examined as a means to modify tissue inflammation and induce angiogenesis. Antibiofouling hydrogels for implantable glucose sensor coatings were prepared from 2‐hydroxyethyl methacrylate, N‐vinyl pyrrolidinone, and polyethylene glycol. Microdialysis sampling was used to test the effect of the hydrogel coating on glucose recovery. VEGF‐releasing hydrogel‐coated fibers increased vascularity and inflammation in the surrounding tissue after 2 weeks of implantation compared to hydrogel‐coated fibers. DX‐releasing hydrogel‐coated fibers reduced inflammation compared to hydrogel‐coated fibers and had reduced capsule vascularity compared to VEGF‐releasing hydrogel‐coated fibers. Hydrogels that released both VEGF and DX simultaneously also showed reduced inflammation at 2 weeks implantation; however, no enhanced vessel formation was observed indicating that the DX diminished the VEGF effect. At 6 weeks, there were no detectable differences between drug‐releasing hydrogel‐coated fibers and control fibers. From this study, hydrogel drug release affected initial events of the foreign body response with DX inhibiting VEGF, but once the drug depot was exhausted these effects disappeared. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Novel thermosensitive polymeric micelles for docetaxel delivery
Authors: Yang Mi , Ding Yitao , Zhang Leyang , Qian Xiaoping , Jiang Xiqun , Liu Baorui 
Published: January 2007

AbstractTargeted delivery of antitumor drugs triggered by hyperthermia has significant advantages in clinical applications, since it is easy to implement and side effects are reduced. To release drugs site‐specifically upon local heating often requires the drugs to be loaded into a thermosensitive polymer matrix with a low critical solution temperature (LCST) between 37 and 42°C. However, the LCSTs of most thermosensitive materials were below 37°C, which limits their application in clinic because they would precipitate once injected into human body and lost thermal targeting function. Herein, we prepared a novel thermosensitive copolymer (poly(N‐isopropylacrylamide‐co‐acrylamide)‐b‐poly (DL‐lactide)) that exhibits no obvious physical change up to 41°C when heated. Docetaxel loaded micelles made of such thermosensitive polymer were prepared by dialysis method and the maximum loading content was found to be up to 27%. The physical properties, such as structure, morphology, and size distribution of the micelles with and without docetaxel were investigated by NMR, X‐ray diffraction, dynamic light scattering, atomic force microscopy, etc. The efficacy of this drug delivery system was also evaluated by examining the proliferation inhibiting activity against different cell linesin vitro. After hyperthermia, the cytotoxicity of docetaxel‐loaded micelles increased prominently. Our results demonstrated that this copolymer could be an ideal candidate for thermal targeted antitumor drug delivery. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Combination of platelet‐rich plasma with polycaprolactone‐tricalcium phosphate scaffolds for segmental bone defect repair
Authors: Rai Bina , Oest Megan E. , Dupont Ken M. , Ho Kee H. , Teoh Swee H. , Guldberg Robert E. 
Published: January 2007

AbstractPorous scaffold biomaterials may offer a clinical alternative to bone grafts; however, scaffolds alone are typically insufficient to heal large bone defects. Numerous studies have demonstrated that osteoinductive growth factor or gene delivery significantly improves bone repair. However, given the important role of vascularization during bone regeneration, it may also be beneficial to incorporate factors that promote vascular ingrowth into constructs. In this study, a strategy combining structural polycaprolactone‐20% tricalcium phosphate (PCL‐TCP) composite scaffolds with platelet‐rich plasma (PRP) was tested. Following bilateral implantation of constructs into 8 mm rat nonunion femoral defects, 3D vascular and bone ingrowth were quantified at 3 and 12 weeks using contrast‐enhanced microcomputed tomography (micro‐CT) imaging. At week 3, PRP‐treated femurs displayed 70.3% higher vascular volume fraction than control femurs. Interestingly, bone volume fraction (BVF) was significantly higher for the empty scaffold group at the early time point. At 12 weeks, BVF measurements between the two groups were statiscally equivalent. However, a greater proportion of PRP‐treated femurs (83%) achieved bone union as compared to empty scaffold controls (33%). Consistent with this observation, biomechanical evaluation of functional integration also revealed a significantly higher torsional stiffness observed for PRP‐treated defects compared to empty scaffolds. Ultimate torque at failure was not improved, however, perhaps due to the slow resorption profile of the scaffold material. Histological evaluation illustrated infiltration of vascularized connective tissue and bone in both groups. Given that bone ingrowth into untreated defects in this model is minimal, PCL‐TCP scaffolds were clearly able to promote bone ingrowth but failed to consistently bridge the defect. The addition of PRP to PCL‐TCP scaffolds accelerated early vascular ingrowth and improved longer‐term functional integration. Taken together, the results of this study suggest that the use of PRP, alone or in combination with other bioactive components, may be an effective approach to augment the ability of porous biomaterial scaffolds to repair orthotopic defects. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007