bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estradiol and its metabolites 4‐hydroxyestradiol and 2‐hydroxyestradiol induce mutations in human breast epithelial cells
Authors: Fernandez Sandra V. , Russo Irma H. , Russo Jose 
Published: November 2005

AbstractAn elevated incidence of breast cancer in women has been associated with prolonged exposure to high levels of estrogens. Our laboratory demonstrated that treatment of the immortalized human breast epithelial cells MCF‐10F with 17β‐estradiol (E2), 4‐hydroxyestradiol (4‐OHE2) or 2‐hydroxyestradiol (2‐OHE2) induces phenotypical changes indicative of neoplastic transformation. MCF‐10F cells treated with E2, 4‐OHE2 or 2‐OHE2 formed colonies in agar methocel and lost their ductulogenic capacity in collagen, expressing phenotypes similar to those induced by the carcinogen benzo[a]pyrene. To investigate whether the transformation phenotypes were associated with genomic changes, cells treated with E2, 4‐OHE2 or 2‐OHE2 at different doses were analyzed using microsatellite markers. Since microsatellite instability (MSI) and loss of heterozygosity (LOH) in chromosomes 13 and 17 have been reported in human breast carcinomas, we tested these parameters in MCF‐10F cells treated with E2, 2‐OHE2, or 4‐OHE2 alone or in combination with the antiestrogen ICI182780. MCF‐10F cells treated with E2 or 4‐OHE2, either alone or in combination with ICI182780, exhibited LOH in the region 13q12.3 with the marker D13S893 located at ∼0.8 cM telomeric to BRCA2. Cells treated with E2 or 4‐OHE2 at doses of 0.007 and 70 nM and 2‐OHE2 only at a higher dose (3.6 μM) showed a complete loss of 1 allele with D13S893. For chromosome 17, differences were found using the marker TP53‐Dint located in exon 4 of p53. Cells treated with E2 or 4‐OHE2 at doses of 0.007 nM and 70 nM and 2‐OHE2 only at a higher dose (3.6 μM) exhibited a 5 bp deletion in p53 exon 4. Our results show that E2 and its catechol estrogen metabolites are mutagenic in human breast epithelial cells. ICI182780 did not prevent these mutations, indicating that the carcinogenic effect of E2 is mainly through its reactive metabolites 4‐OHE2 and 2‐OHE2, with 4‐OHE2 and E2 being mutagenic at lower doses than 2‐OHE2. © 2005 Wiley‐Liss, Inc.
A point mutation in the NFYC gene generates an antigenic peptide recognized by autologous cytolytic T lymphocytes on a human squamous cell lung carcinoma
Authors: Takenoyama Mitsuhiro , Baurain Jean‐Françis , Yasuda Manabu , So Tomoko , Sugaya Masakazu , Hanagiri Takeshi , Sugio Kenji , Yasumoto Kosei , Boon Thierry , Coulie Pierre G. 
Published: November 2005

AbstractWe have identified an antigen recognized by cytolytic T lymphocytes (CTL) on the autologous tumor cells of a nonsmall cell lung cancer patient. The antigenic peptide, presented by HLA‐B*5201 molecules, was encoded by a mutated sequence in the gene coding for the C subunit of transcription factor NF‐Y. The mutation was present in the tumor sample from which the cell line was derived, and appeared to be unique to the tumor of this patient. In a lymph node draining the tumor, precursors of CTL recognizing the autologous tumor cells were detected at a frequency of about 1/30,000 of the CD8 cells, and 85% of them recognized the mutated NF‐YC peptide, suggesting that the patient mounted a T cell response against this antigen. These results strengthened the notion that unique tumor‐specific antigens are highly represented not only in melanoma but also in other types of tumors, like nonsmall cell lung cancer. © 2005 Wiley‐Liss, Inc.
Is there an association between SV40 contaminated polio vaccine and lymphoproliferative disorders? An age–period–cohort analysis on Norwegian data from 1953 to 1997
Authors: Thu Guri Olsen , Hem Ling Yuan , Hansen Svein , Møller Bjørn , Norstein Jarle , Nøkleby Hanne , Grotmol Tom 
Published: November 2005

AbstractBetween 1955 and 1963, an estimated number of 150 million people in various parts of the world, including Norway, received poliomyelitis vaccine possibly contaminated with infectious simian virus 40 (SV40). Human studies have investigated the hypothesised association between SV40 and various cancers, but the results have so far been contradicting. The aim of the present study was to examine Norwegian cancer incidence data to assess a possible association between birth cohorts assumed to have been subjected to the vaccine and the incidence rate of lymphoproliferative disorders (excluding Hodgkin's lymphoma), further subdivided into non‐Hodgkin's lymphoma (NHL), lymphocytic leukemia and plasma cell neoplasms. Between 1953 and 1997, the incidence rate of lymphoproliferative diseases combined increased about 3‐fold in both males and females. Subgroup analysis showed that this increase was largely attributable to NHL. Age–period–cohort modelling of the subgroups, as well as of all groups combined, showed that the cohort effect was more prominent than the period effect. However, the variations in incidence patterns across the birth cohorts did not fit with the trends that would be expected if a SV40 contaminated vaccine did play a causative role. Thus, our data do not support the hypothesis of an association between the vaccine and any subgroup of lymphoproliferative diseases. © 2005 Wiley‐Liss, Inc.
Attachment, growth, and activity of rat osteoblasts on polylactide membranes treated with various low‐temperature radiofrequency plasmas
Authors: Gugala Zbigniew , Gogolewski Sylwester 
Published: November 2005

AbstractNonporous and porous membranes from poly(L/DL‐lactide) 80/20% were treated with low‐temperature oxygen, ammonia, or sulphur dioxide–hydrogen plasmas and the late effects of plasma treatment on physicochemical characteristics of the membranes' surface were analyzed. The plasma treatment resulted in the permanent attachment of sulphur and nitrogen functionalities to the membrane's surface, and increased the surface concentration of oxygen, thereby increasing the surface wettability. To assess whether the plasma treatment affects the cellular response, primary rat osteoblasts were cultured on nontreated and plasma‐treated nonporous and microporous membranes, and attachment, growth, and activity of cells were investigated. It was found that attachment and growth of osteoblasts on all the plasma‐treated membranes were greater compared with nontreated controls. The treatment with ammonia plasma was most efficacious. The beneficial effects of plasma treatment on cells were most pronounced for microporous polylactide membranes irrespective of the plasma used. The results of the study suggest that the treatment of porous polylactide structures with plasma can be an effective means of enhancing their suitability for tissue engineering. Plasma exposure may also have an advantageous effect on bone healing when polylactide membranes are used to treat bone defects. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Fabrication and evaluation of porous 2,3‐dialdehydecellulose membrane as a potential biodegradable tissue‐engineering scaffold
Authors: RoyChowdhury P. , Kumar V. 
Published: November 2005

AbstractA simple, novel method to produce porous 2,3‐dialdehydecellulose (DAC) membranes as a potential tissue‐engineering scaffold has been developed from methylolcellulose by the simultaneous water‐induced phase separation and sodium chloride salt leaching techniques, followed by oxidation with sodium periodate in water. Membrane pores increased in size with increasing weight or particle size of the sodium chloride salt. The porosity of the membrane was not affected by the salt particle size, but it increased with an increase in the salt weight to 60%. At higher salt weight percentages, no significant change in the membrane porosity was observed. The oxidation step had no effect on the membrane porosity or pore size. All membranes with a porosity value ranging between 87 and 93% showed interconnected porous structures. The use of these membranes as a potential tissue‐engineering scaffold was evaluated with the use of human neonatal skin fibroblast cells. Confocal microscopy showed cell attachment and spreading on these membranes. Immunohistochemical tests revealed the presence of collagen type III and fibronectin, indicating that the cells were viable and formed the extracellular matrix. In conclusion, the DAC membrane supports cell adhesion and proliferation and hence shows potential to be used as a tissue‐engineering scaffold. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Thin calcium phosphate coatings on titanium by electrochemical deposition in modified simulated body fluid
Authors: Peng Ping , Kumar Sunil , Voelcker Nicolas H. , Szili Endre , Smart Roger St. C. , Griesser Hans J. 
Published: November 2005

AbstractAdherent and optically semitransparent thin calcium phosphate (CaP) films were electrochemically deposited on titanium substrates in a modified simulated body fluid at 37°C. Coatings deposited by using periodic pulsed potentials showed better adhesion and better mechanical properties than coatings deposited with use of a constant potential. Scanning electron microscopy was used to study the morphology of the coatings. The coatings displayed a polydispersed porous structure with pores in the range of a few nanometers to 1 μm. Furthermore, X‐ray diffractometry and the O(1s) satellite peaks in X‐ray photoelectron spectroscopy indicated that the coatings possessed a similar surface chemistry to that of natural bone minerals. These results were confirmed by inductively coupled plasma optical emission spectrometry, which yielded a Ca:P ratio of 1.65, close to that of hydroxyapatite. Contact mode atomic force microscopy (AFM) showed the average thickness of the coatings was in the order of 200 nm. Root‐mean‐square (RMS) roughness values, also derived by AFM, were shown to be much higher on the titanium‐CaP surfaces in comparison with untreated titanium substrates, with RMS values of about 300 and 110 nm, respectively. Cell culture experiments showed that the CaP surfaces are nontoxic to MG63 osteoblastic cells in vitro and were able to support cell growth for up to 4 days, outperforming the untreated titanium surface in a direct comparison. These easily prepared coatings show promise for hard‐tissue biomaterials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Extensive H+release by bone substitutes affects biocompatibilityin vitrotesting
Authors: Jäger M. , Fischer J. , Schultheis A. , Lensing‐Höhn S. , Krauspe R. 
Published: November 2005

AbstractBone substitutes are widespread in orthopedic and trauma surgery to restore critical bony defects and/or promote local bone healing. Cell culture systems have been used for many years to screen biomaterials for their toxicity and biocompatibility. This study applies a human bone marrow cell culture system to evaluate the toxicin vitroeffects of soluble components of different bone substitutes, which are already in clinical use. Different specimens of tricalcium phosphates (TCP) (Vitoss™, Cerasorb™), nondecalcified bovine bone (Lubboc™), demineralized human bone matrices (DBM) (Grafton™ Flex/Putty), and collagen I/III matrix (ACI‐Maix™) were tested in Dulbecco's modified Eagle's medium (DMEM) and Mesencult™ culture solution and compared with a biomaterial‐free cell culture. Biocompatibility parameters were cell viability evaluated by phase‐contrast microscopy and laser flow cytometry, morphology, and the local H+release by bone substitutes. There were significant differences (p< 0.05) between the tested biomaterials and culture solutions. Collagen I/III, nondemineralized bovine bone, and TCP materials showed advantages for cell survival over other tested biomaterials (average values of vital cells/mL MesenCult™/DMEM: Collagen I/III: 1090/1083; Vitoss™: 893/483; Cerasorb™: 471/523; Lubboc™: 815/410; Grafton™ Putty: 61/44; Grafton™ Flex: 149/57). Especially the DBM materials lead to a significant decrease of pH, which is considered to be a major factor for cell death. DMEM culture solution supports cell survival for those bone substitutes that induce an alkaline reaction, whereas MesenCult™ media promotes cell vitality in biomaterials, which leads to an acidification of culture solution. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Effect of filament diameter and extracellular matrix molecule precoating on neurite outgrowth and Schwann cell behavior on multifilament entubulation bridging device in vitro
Authors: Wen Xuejun , Tresco Patrick A. 
Published: November 2005

AbstractAt present there is no clinically effective treatment for injuries or pathological processes that disrupt the continuity of axons in the mature central nervous system. However, a number of studies suggest that a tremendous potential exists for developing biomaterial based therapies. In particular, biomaterials in the form of bridging substrates have been shown to support at least some level of axonal regeneration across the lesion site, but display a limited capacity for directing axons toward their targets. To improve the directionality and outgrowth rate of the axonal regeneration process, filaments and tubes appear promising, but the technology is far from optimized. As a step toward optimization, the influence of filament diameter and various extracellualr matrix coatings on nerve regeneration was evaluated in this article using a dorsal root ganglion (DRG) explant model. An increasing pattern of alignment and outgrowth of neurites in the direction parallel the long axis of the packed filament bundles with decreasing filament diameters ranging from supracellular and beyond (500 to 100 μm), cellular (30 μm), down to subcellular size (5 μm) was observed. Such effects became most prominent on filament bundles with individual filament diameters in the range of cellular size and below (5 and 30 μm) where highly directional and robust neuronal outgrowth was achieved. In addition, laminin‐coated filaments that approached the size of spinal axons support significantly longer regenerative outgrowth than similarly treated filaments of larger diameter, and exceed outgrowth distance on similarly sized filaments treated with fibronectin. These data suggested the feasibility of using a multifilament entubulation bridging device for supporting directional axonal regeneration. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Three‐dimensional culture of human osteoblastic cells in chitosan sponges: The effect of the degree of acetylation
Authors: Amaral I.F. , Sampaio P. , Barbosa M.A. 
Published: November 2005

AbstractIn this investigation, the effect of the degree of acetylation (DA) of chitosan on the behavior of human osteoblastic MG‐63 cells cultured in three‐dimensional chitosan matrices was assessed. Chitosan sponges with DAs in the range of 4 to 49% were prepared and characterized in terms of microstructure, porosity, and pore size. Collagen sponges were used as 3D control. Cell proliferation was determined using the MTT assay while the retention of the osteoblastic phenotype was monitored by assaying alkaline phosphatase activity. Cell morphology, cytoskeletal organization, and viability were assessed using different microscopy techniques. Chitosan sponges showed a similar microstructure regardless the DA, except for the highest DA used, where a more heterogeneous pore distribution was observed. In terms of cell proliferation, alkaline phosphatase activity and cell viability, cells cultured in chitosan scaffolds performed as well as in the 3D control regardless the DA, except for the highest DA used, where an inhibitory effect on cell proliferation was found. However, while in sponges with DAs ≤ 13% cells attached and spread displaying long cell filopodia and numerous cell‐to‐cell contacts, in sponges with higher DAs cells tended to remain spherical and grow into spheroid‐like cellular aggregates. In the present study, the DA played a key role in determining the affinity of osteoblastic cells towards the substrates, possibly by influencing the nature of the initial adsorbed protein layer. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Cellular response to phase‐separated blends of tyrosine‐derived polycarbonates
Authors: Bailey LeeAnn O. , Becker Matthew L. , Stephens Jean S. , Gallant Nathan D. , Mahoney Christine M. , Washburn Newell R. , Rege Aarti , Kohn Joachim , Amis Eric J. 
Published: November 2005

AbstractTwo‐dimensional thin films consisting of homopolymer and discrete compositional blends of tyrosine‐derived polycarbonates were prepared and characterized in an effort to elucidate the nature of different cell responses that were measured in vitro. The structurally similar blends were found to phase separate after annealing with domain sizes dependent on the overall composition. The thin polymer films were characterized with the use of atomic force microscopy (AFM), water contact angles, and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) and significant changes in roughness were measured following the annealing process. Genetic expression profiles of interleukin‐1β and fibronectin in MC3T3‐E1 osteoblasts and RAW 264.7 murine macrophages were measured at several time points, demonstrating the time and composition‐dependent nature of the cell responses. Real‐time reverse transcriptase polymerase chain reaction (RT‐PCR) depicted upregulation of the fibronectin gene copy numbers in each of the blends relative to the homopolymers. Moreover, the interleukin‐1β expression profile was found to be compositionally dependent. The data suggest strongly that optimal composition and processing conditions can significantly affect the acute inflammatory and extracellular matrix production responses. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro enzymatic stability of dendritic peptides
Authors: Yang Hu , Lopina Stephanie T. 
Published: November 2005

AbstractPEGylated polyamidoamine (PAMAM) dendrimers as drug carriers have been a topic of interest because of their biomedically favorable features, including minimal toxicity, reduced immunogenicity, and excellent solubility in aqueous and most organic solutions. A PEG shell on dendrimer surface may provide steric hindrance, known as stealth properties of PEG, to stabilize drug molecules to be delivered. In this article, the effects of PEG and coupling sequence of drug, PEG, and dendrimer in modulating the stability of delivered drug molecules were evaluated. N‐succinyl‐Ala‐Ala‐Pro‐Phe‐p‐nitroanilide was chosen as a model peptide. Dendritic peptides, that is, peptide‐dendrimer, peptide‐PAMAM‐PEG, and peptide‐PEG‐dendrimer, were constructed based on Starburst™ G3.0 PAMAM dendrimer and characterized by 1H‐NMR spectroscopy. Hydrolysis of dendritic peptides was catalyzed by α‐chymotrypsin in pH 7.4 PBS buffer containing 5% DMF (v/v) at room temperature. The enzymatic stability of dendritic peptides was peptide‐PAMAM‐PEG > peptide‐PAMAM > free peptide > peptide‐PEG‐PAMAM. The ratio of PEG/peptide could be reduced for increasing peptide loading while maintaining the delivered peptides' relatively high enzymatic stability. The quantitative analysis of dendritic peptide/enzyme interactions provided the understandings of the molecular structure/stability relationships of dendrimer/drug for the design of an optimal PEGylated dendrimer‐based drug‐delivery system. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Guided tissue regeneration for using a chitosan membrane: An experimental study in rats
Authors: Kuo Shyh Ming , Chang Shwu Jen , Chen Ta Wei , Kuan Tang Ching 
Published: November 2005

AbstractBarrier membranes are employed clinically to deflect the growth of gingival tissues away from root surface. They provide an isolated space over the regions with the defective tissues that allow the relatively slow growing periodontal ligament fibroblasts to be repopulated onto the root surface. Several makes of bioabsorbable membranes are now commercially available. In this study, we have employed chitosan as barrier membrane material and evaluated it for a guided tissue regeneration application. Three types of chitosan membranes: Chi‐NaOH, Chi‐Na5P3O10, and Chi‐Na2SO3(each was gelated by NaOH, crosslinked by Na5P3O10 and Na2SO3, respectively), were prepared to be evaluated by the following categories: the mechanical strength to create an effective space, the rapid rate to reach hydrolytic equilibrium in phosphate‐buffered solution, and the ease of clinical manipulative operations. Consequently, standardized, transosseous and critical sized skull defects were made in adult rats and the defective regions were covered with the specifically prepared chitosan membranes. After 4 weeks of recovering, varying degrees of bone healing were observed beneath the chitosan membranes in comparison to the control group. The chitosan covered regions showed a clear boundary space between connective tissues and bony tissues. Apparently, this process resulted in a good cell occlusion and beneficial osteogensis effect to the bone. As for the control group, the bone defect was filled with connective tissue, and a destruction of the integrity of newly formed bone was observed. Among the chitosan membranes tested in this study, Chi‐NaOH membrane provided a higher percentage of new bone formation than those from the Chi‐Na5P3O10 and Chi‐Na2SO3 families. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
New physically and chemically crosslinked hyaluronate (HA)‐based hydrogels for cartilage repair
Authors: Huin‐Amargier Cécile , Marchal Philippe , Payan Elisabeth , Netter Patrick , Dellacherie Edith 
Published: November 2005

AbstractWhen dissolved in aqueous solutions, sodium hyaluronate substituted with low amounts of alkyl chains [amphiphilic hyaluronate (HA)] can give rise to hydrogels thanks to intermolecular reversible hydrophobic interactions, leading to a three‐dimensional (3D) network. Such hydrogels possess shear‐thinning properties and can thus be injected in cartilage defect to promote chondrocyte proliferation and cartilage repair. However, these hydrogels are only physically crosslinked and can progressively loose their 3D structure when they are in contact with aqueous fluids. To overcome this drawback, HA derivatives substituted with dodecyl chains were chemically crosslinked by a difunctional reagent, tetraethylene glycol ditosylate (TEG‐diOTs). To preserve the shear‐thinning properties of amphiphilic HA, small amounts of TEG‐diOTs were used so as to obtain a low chemical crosslinking ratio. After optimization of the synthesis parameters, aqueous solutions of the HA derivatives, crosslinked both physically and chemically, were obtained, with rheological properties improved compared to the amphiphilic polymers. As the hydrogels are aimed to cartilage repair, they were sterilized by wet heating; the effect of this treatment on the polymer characteristics was analyzed by different techniques. A similar study was carried out on HA derivatives stored under conditions mimicking physiological ones. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006