bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variation in the COX‐2 gene and the association with prostate cancer risk
Authors: Shahedi K. , Lindström S. , Zheng S.L. , Wiklund F. , Adolfsson J. , Sun J. , Augustsson‐Bälter K. , Chang B.‐L. , Adami H.‐O. , Liu W. , Grönberg H. , Xu J. 
Published: February 2006

AbstractCOX‐2 is a key enzyme in the conversion of arachidonic acid to prostaglandins. The prostaglandins produced by COX‐2 are involved in inflammation and pain response in different tissues in the body. Accumulating evidence from epidemiologic studies, chemical carcinogen‐induced rodent models and clinical trials indicate that COX‐2 plays a role in human carcinogenesis and is overexpressed in prostate cancer tissue. We examined whether sequence variants in the COX‐2 gene are associated with prostate cancer risk. We analyzed a large population‐based case–control study, cancer prostate in Sweden (CAPS) consisting of 1,378 cases and 782 controls. We evaluated 16 single nucleotide polymorphisms (SNPs) spanning the entire COX‐2 gene in 94 subjects of the control group. Five SNPs had a minor allele frequency of more than 5% in our study population and these were genotyped in all case patients and control subjects and gene‐specific haplotypes were constructed. A statistically significant difference in allele frequency between cases and controls was observed for 2 of the SNPs (+3100 T/G and +8365 C/T), with an odds ratio of 0.78 (95% CI = 0.64–0.96) and 0.65 (95% CI = 0.45–0.94) respectively. In the haplotype analysis, 1 haplotype carrying the variant allele from both +3100 T/G and +8365 C/T, with a population frequency of 3%, was also significantly associated with decreased risk of prostate cancer (p= 0.036, global simulatedp‐value = 0.046). This study supports the hypothesis that inflammation is involved in prostate carcinogenesis and that sequence variation within the COX‐2 gene influence the risk of prostate cancer. © 2006 Wiley‐Liss, Inc.
p53 mutation spectra for squamous cell carcinomas at different levels of human bronchial branches
Authors: Shimmyo Takuo , Hashimoto Takehisa , Kobayashi Yasuhito , Miyagi Youhei , Ishikawa Yuichi , Nakagawa Ken , Osada Hiroaki , Tsuchiya Eiju 
Published: February 2006

AbstractThe question of whether squamous cell carcinomas (SCCs) arising in different sites of lung are caused by different etiological factors is of obvious importance for prevention, early detection and effective treatment. We here subclassified a large series of resected SCCs (74 cases) into 3 tumor‐sites, central (main to segmental bronchi), intermediate (subsegmental to sub‐subsegmental) and peripheral (distal to sub‐subsegmental bronchi), and examined relationships with p53 mutational spectra and smoking history to provide clues to etiological factors. The rate for G→A transitions at CpG sites considered to be caused by endogenous mechanism was higher in central (40%) than in intermediate (0%) and peripheral (14%) lesions, in spite of highest percentage of heavy smokers. In contrast, G→T transversions associated with tobacco smoke carcinogens were most frequent (50%) in the intermediate location, although proportions of heavy smoker's ratio were the same among the locations when confined to p53 mutation cases. In the periphery, other mutations were highest (67%) compared with 33 and 50% in the central and intermediate regions, respectively. Thus, different etiological factors may be playing causal roles in the development of SCCs in different locations of bronchial tree. Furthermore, the results suggest that more extensive study of the influence of tobacco smoke carcinogens on endogenous mechanisms is warranted. © 2006 Wiley‐Liss, Inc.
In vivo biostability of polysiloxane polyether polyurethanes: Resistance to biologic oxidation and stress cracking
Authors: Ward Robert , Anderson James , McVenes Rick , Stokes Ken 
Published: February 2006

AbstractPolyether polyurethanes are extremely interesting for use in implantable devices. They are, however, susceptible to autoxidative degradation and stress cracking. One approach to improving biostability is to replace some of the polyether with polysiloxane. Shore 80A polyether polyurethanes with 20% (PS‐20) and 35% (PS‐35) polysiloxane were strained to 400% elongation and implanted in rabbits. Twelve weeks implant showed that both were significantly more biostable than their polysiloxane‐free controls. After 18 months implant, PS‐20 developed some localized tensile fractures. PS‐35 showed no sign of visual damage. Infrared surface analysis does not allow direct evaluation of autoxidation because the SiOSi stretch peaks mask the polyether bands. Secondary indicators suggest possible very slight autoxidation of both PS‐20 and PS‐35 surfaces, but not enough to develop cracks. The polysiloxane‐free controls did show substantial infrared evidence of autoxidation. Molecular weights of long‐term PS‐20 and PS‐35 explants were negligibly lower. In comparison, the polysiloxane‐free control suffered 35% molecular weight loss. Positive and negative controls performed as expected. PS‐20 is recommended for devices that do not sustain high fixed loads. PS‐35 is dramatically more biostable than its unmodified polyether analogues and is recommended for use in chronically implantable devices. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Bioactive glass/polymer composite materials with mechanical properties matching those of cortical bone
Authors: Koleganova Veronika A. , Bernier Suzanne M. , Dixon S. Jeffrey , Rizkalla Amin S. 
Published: February 2006

AbstractStress shielding resulting from mismatch in dynamic mechanical properties contributes to the reduced stability of osseous implants. Our objective was to develop biocompatible composites having mechanical properties similar to those of cortical bone. Polymers of urethane dimethacrylate (UDMA) and 2‐hydroxyethyl methacrylate (HEMA, 0–20%) and composites containing bioactive glass particles (70% SiO2, 25% CaO, and 5% P2O5), with or without silane treatment were prepared. Young's moduli of composites containing silane‐treated glass (16 GPa) were significantly greater than those of composites containing untreated glass (12–13 GPa) or of unfilled polymers (5–6 GPa). Bioactive glass reduced water sorption by the composites and incorporation of silane‐treated glass prevented HEMA‐induced increases in water sorption. Osteoblast‐like cells attached equally well to UDMA polymer and composite containing silane‐treated bioactive glass. Thus, silane treatment improved the mechanical properties of bioactive glass composites without compromising biocompatibility. This material has a Young's modulus comparable to that of cortical bone. Therefore, silane‐treated bioactive glass composites, when used as implant or cement materials, would reduce stress shielding and improve implant stability. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Synthetic biodegradable microparticles for articular cartilage tissue engineering
Authors: Thissen H. , Chang K.‐Y. , Tebb T. A. , Tsai W.‐B. , Glattauer V. , Ramshaw J. A. M. , Werkmeister J. A. 
Published: February 2006

AbstractArticular cartilage tissue engineering procedures require the transplantation of chondrocytes that have been expanded in vitro. The expansion is carried out for a considerable time and can lead to a modulation of cell phenotype. However, microcarrier cultures have been shown to allow cell expansion while maintaining the phenotype. Here, we have used the biodegradable polyester poly(lactide‐co‐glycolide) (PLGA) in the form of microspheres and irregular shaped microparticles with a diameter between 47 and 210 μm. Surface modification of particles was carried out by ammonia plasma treatment and subsequent adsorption of collagen. Alternatively, particles were modified by partial hydrolysis and subsequent immobilization of an amine‐terminated dendrimer. Each surface modification step was characterized by X‐ray photoelectron spectroscopy. The effectiveness of the surface modification procedures was demonstrated by in vitro cell culture experiments using sheep articular cartilage chondrocytes. A significant influence of both the particle shape and the surface chemistry on the proliferation rate was observed while the phenotype was maintained independent of the surface chemistry or particle shape. Chondrocytes cultured on PLGA microspheres were further assessed for cartilage tissue formation in collagen type I gels in nude mice. The tissue that were formed showed the appearance of a hyaline‐like cartilage and the presence of the microspheres substantially reduced the degree of collagen gel contraction over 1–2 months. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Osteoblast response to plasma‐spray porous Ti6Al4V coating on substrates of identical alloy
Authors: Saldaña L. , González‐Carrasco J.L. , Rodríguez M. , Munuera L. , Vilaboa N. 
Published: February 2006

AbstractWe have evaluated the in‐vitro biocompatibility of Ti6Al4V alloy coated by plasma spraying with an identical alloy. These surfaces are widely used in cementless prosthetic components, although osteoblasts behavior on this treated alloy has not been evaluated to date. Cross sectional examination revealed a thick and rough coating of identical composition without sign of delamination. Within the coating, small discontinuities and nonconnected pores were observed. Osteoblast response was evaluated by assessing cell adhesion, proliferation, and differentiation of primary cultures of human osteoblastic cells. Compared to the polished alloy, osteoblast adhesion measured as cell attachment and actin network reorganization was delayed on the plasma‐sprayed surface. Cell proliferation and viability were also impaired on the rough surface. Several informative markers of osteoblastic differentiation such as procollagen I peptide, alkaline phosphatase, osteocalcin, osteoprotegerin, and mineralized nodule formation were evaluated and indicated that the plasma‐sprayed alloy favored a more differentiated phenotype than polished alloy. Taken together, our in vitro results indicate that successful osseointegration of plasma spraying of Ti6Al4V with an identical alloy is mediated by modulation of osteoblastic differentiation and mineralization. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro and in vivo release of gentamicin from biodegradable discs
Authors: Naraharisetti Pavan Kumar , Guan Lee Herman Chian , Fu Yin‐Chih , Lee Duu‐Jong , Wang Chi‐Hwa 
Published: February 2006

AbstractOsteomyelitis is an infection of the bone and successful treatment involves the removal of the affected bone and the tissue by a surgical procedure following prolonged systemic and local antibiotic therapy for 4 to 6 weeks. The current local treatment is done by poly methyl methacrylate (PMMA) beads loaded with gentamicin and PMMA, being nondegradable, is to be removed by a second surgical procedure. The current study aims to develop a biodegradable composition that gives sustained release and hence reducing the need for a second surgery. Gentamicin‐loaded discs were produced by compressing microparticle–gentamicin mixture obtained by spray drying a mixture of gentamicin in a solution of a biodegradable polymer. Different copolymers of poly (DL‐lactic‐co‐glycolic acid) (PLGA) were used to study the effect of copolymer ratio and the hydrophilic–hydrophobic nature of the polymer. Theoretical drug loading up to 25% were studied and it was observed that 10% drug loading was optimum for gentamicin to be used as solid in spray drying. The results showed that about 60% of the drug is released in about 5 to 6 days and the remaining drug is released in about 30 days in total. An in vivo study was carried on rabbit femur and the local area and systemic concentration of gentamicin was monitored. It was observed that the local area concentration of gentamicin was above minimum inhibitory concentration for more than 20 days and this was also validated by computer simulations. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Functional properties and performance of new and reprocessed coronary angioplasty balloon catheters
Authors: Fedel Mariangela , Tessarolo Francesco , Ferrari Paolo , Lösche Christian , Ghassemieh Nikou , Guarrera Giovanni Maria , Nollo Giandomenico 
Published: February 2006

AbstractThe need of health costs control has prompted the reuse of devices originally manufactured for single use only. To assess reprocessing feasibility of disposable medical devices, hygienic, technical, and functional aspects must be taken into account in addition to economical, ethical, and legal implications. This study aims to characterize coronary angioplasty catheters and to evaluate performance changes induced by reprocessing. Multiple analysis including crossing profile, slipperiness, compliance, mechanical, and burst pressure tests were performed at different steps of the protocol on 25 catheters reprocessed up to two times. The results highlighted that both use and reprocessing can affect the features of angioplasty catheters. Mechanical stress caused by clinical inflation and thermal–chemical stress undergone by polymers during cleaning and sterilization procedures caused partial modifications of material properties, inducing an overall shrinking effect on balloons. Compliance tests reported a maximum variation of 6.2% from nominal values, showing the conformity of reprocessed devices with manufacturers' original specifications (±10%). The burst pressure of reprocessed devices was 80% higher than the rated burst pressure certified by manufacturers, thus reducing concerns of breakage during reuse. A strict dependence on device model in the behavior of catheters was found, especially for balloons crossing profile and slipperiness. Main changes occurred after the first reprocessing cycle, while a second cleaning and sterilization did not introduce further significant alterations. On the whole, the magnitude of modifications introduced up to two reprocessing cycles did not compromise catheters performance. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Biodegradable and complexed microspheres used for sustained delivery and activity protection of SOD
Authors: Wang Ye , Gao Jian‐Qing , Zheng Cai‐Hong , Xu Dong‐Hang , Liang Wen‐Quan 
Published: February 2006

AbstractTo develop a new protein delivery system for superoxide dismutase (SOD), biodegradable materials like poly(DL‐lactide‐co‐glycolide) (PLGA), alginate, and chitosan were used for preparing PLGA microspheres and alginate–chitosan microspheres, which were used for encapsulating protein. Alginate–chitosan microspheres showed much higher entrapment efficiency (91.08% ± 1.28%) than that of PLGA microspheres (36.42% ± 1.81%). In vitro release study showed that SOD presented a sustained release character in the preparation of these biodegradable materials. After 15 days, 43.72% ± 0.43% of protein was released from alginate–chitosan microspheres, while there was 62.96% ± 3.95% of protein release from PLGA microspheres. However, alginate–chitosan demonstrated that it was a better material to control the burst release of protein from microspheres. Furthermore, SOD activity in microspheres was evaluated, and the results showed that microspheres protected the activity of protein to some extent. Finally, PLGA–alginate–chitosan complex microspheres were constructed and the release character in vitro demonstrated that this preparation could not only prolong the release of drug but also decrease the burst release. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Can accelerated aqueous aging simulate in vivo oxidation of gamma‐sterilized UHMWPE?
Authors: Mazzucco Daniel C. , Dumbleton John , Kurtz Steven M. 
Published: February 2006

AbstractOxidation of ultrahigh molecular weight polyethylene (UHMWPE) γ‐sterilized arthroplasty components occurs in vivo. Though accelerated in vitro protocols have been developed to test the relative oxidation resistance of various types of UHMWPE, it is desirable to develop an accelerated aging protocol that more closely approximates the in vivo environment. The goal of this study was to investigate the effects of temperature, solute, and oxygen partial pressure in aqueous media on the oxidation of γ‐sterilized UHMWPE, as the basis for the development of improved accelerated aging protocols. The accelerated oxidation behavior of γ‐sterilized GUR 1150 was studied at 60 and 70°C in an open vessel filled with distilled water or PBS in equilibrium with a controlled partial pressure of oxygen. The extent of oxidation was assessed using standardized mechanical and chemical evaluation techniques (small punch and Fourier transform infrared spectroscopy). Accelerated oxidation of UHMWPE was achieved in aqueous environments; however, both clinically relevant and nonrelevant oxidation species (e.g., aldehydes) were observed for long aging times at 60°C, and for all aging times at 70°C. These findings point the way to the development of an accelerated aging protocol. The current data, considered in conjunction with real‐time aging studies, suggest that a temperature between body temperature and 60°C may accelerate oxidative degradation without altering the oxidative patterns encountered in vivo. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
BOLD signal in the motor cortex shows a correlation with the blood volume of brain tumors
Authors: Lüdemann Lutz , Förschler Annette , Grieger Wolfgünter , Zimmer Claus 
Published: February 2006

AbstractPurposeTo investigate whether and how the blood‐oxygenation‐level–dependent (BOLD) functional MRI (fMRI) signal is modified by brain tumors.Materials and MethodsThe BOLD signal depends on the perfusion, which in turn may be affected in the presence of a tumor. Some studies have demonstrated a reduced BOLD signal in the tumor‐bearing hemisphere. The BOLD signal variation in the motor cortex area was studied with finger tapping in a brain tumor group and a control group. An a priori volume‐of‐interest (VOI)‐based method was applied that allows quantification of the mean BOLD signal amplitude and extent of activated volume. BOLD signal amplitude and activated volume were correlated with the extent of edema, a mass effect on the central sulcus, tumor volume, distance of tumor to somatosensory cortex, and tumor blood volume.ResultsIn the tumor group the ipsilateral activated volume was reduced by 21% (P = 0.025) and the mean signal amplitude was reduced by 16% (P = 0.004). The mean BOLD signal amplitude shows a significant correlation with the total intratumoral blood volume (P = 0.014).ConclusionWe concluded that the peritumoral perfusion was reduced resulting due to a tumor aspirating perfusion (steal phenomenon). J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Vertebrae adjacent to spinal bone lesion are inconsistent reference markers: A magnetic resonance spectroscopic viewpoint
Authors: Rumpel Helmut , Chan Ling Ling , Chan Lai Peng , Png Meng Ai , Tan Raymond K.L. , Lim Winston E.H. 
Published: February 2006

AbstractPurposeTo ascertain the suitability of vertebrae adjacent to spinal bone lesions as a signal intensity reference on MRI, and compare the MR spectroscopic appearance of vertebral body compression fractures due to malignant tumor infiltration, bone weakening (e.g., osteoporosis), and/or minor trauma.Materials and MethodsTwenty‐five patients with spinal compression fractures underwent routine spinal MRI with an additional 1H MRS study protocol to assess the percent fat fraction of the compressed vertebrae as well as the adjacent bony environment. Peak areas for water and total lipid were calculated from short‐TE single‐voxel 1H MR spectra using the LCModel analyzing tool.ResultsThere were consistent water‐only patterns in the fractured vertebra suggesting either near complete marrow replacement by malignant tissue or local edematous fluid/hemorrhage within the marrow spaces. However, the adjacent vertebrae showed a wide range of patterns from a dominant lipid signal to the inverse of a pronounced water level. These results far exceed the normal variation expected based on age and sex.ConclusionThe results suggest that the adjacent vertebrae may not be an accurate reference, especially in diffusion‐weighted imaging (DWI), because of the large difference between the two compartments. Furthermore, in the case of gradient‐echo measurements, the in‐phase vs. opposed‐phase effects are significant. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Effects of green tea extract on the quality of bread made from unfrozen and frozen dough processes
Authors: Wang Rong , Zhou Weibiao , Yu Huei‐Huei , Chow Weng‐Fai 
Published: February 2006

AbstractTwo different green tea extracts (GTE‐A and ‐B) as a rich source of tea catechins were incorporated into a no‐time bread‐making process, where bread made from the unfrozen and frozen dough processes was compared by specific volume and texture profile. GTE‐A and ‐B both exhibited significant effects on bread volume and firmness, but to a different extent. GTE‐A with higher content of tea catechins (73%) at a level of 1.5 g kg−1 flour was found to lead to a significant reduction in bread volume in unfrozen dough process and an increment in firmness during storage for 4 days at ambient temperature (22 °C). GTE‐B, with a lower content of catechins (60%), had relatively mild effects on the bread quality. Significantly negative effects were evident starting at a higher level of 5.0 g kg−1 flour in unfrozen dough process. Frozen storage showed more predominant deteriorating effects than the GTEs over a period of 9 weeks frozen storage at −20 °C. Copyright © 2006 Society of Chemical Industry
Grafting to improve nitrogen‐use efficiency traits in tobacco plants
Authors: Ruiz Juan M , Rivero Rosa M , Cervilla Luis M , Castellano Rosa , Romero Luis 
Published: February 2006

AbstractNitrate plays a major role in the yield and quality of tobacco plants. This work explored the nitrogen‐use efficiency (NUE) and how it can be affected by grafting. Two experiments were designed: in the first, using six commercial tobacco cultivars, the best cultivar for the NUE was selected and analysed for foliar NO3− content, total N, nicotine and nitrate reductase (NR) activity. The results showed the cultivar H‐20 to have the best performance on NUE. It was further featured by the highest NR activity and total N and by the lowest NO3− and nicotine content, resulting in the highest foliar leaf biomass production and quality. In the second experiment it was tested whether the cultivar H‐20 could be used as rootstock to improve the NUE of the other cultivars under study. The results showed that the grafted plants had improved the NO3− assimilation with respect to non‐grafted plants. Hence grafting tobacco plants can be used as a quick and effective method to improve NUE, which has beneficial implications for human health and for a reduction in environmental pollution. Copyright © 2006 Society of Chemical Industry
Structural Studies on Syndiotactic 1,2‐Poly(1,3‐butadiene) by X‐Ray Measurements and Molecular Mechanics Calculations
Authors: Napolitano Roberto , Pirozzi Beniamino , Esposito Simona 
Published: February 2006

AbstractSummary: Two samples of syndiotactic l,2‐poly(1,3‐butadiene) with different constitutional and configurational regularities were characterized by DSC analysis and X‐ray powder diffraction. Possible models of the crystal structure were obtained by molecular mechanics calculations performed with various sets of potential functions. X‐ray powder profiles calculated for these models were in good agreement with experiments. The agreement between simulated and experimental X‐ray powder profiles was improved by taking into account, in the calculated models, the presence of configurational defects. This indicates that configurational defects can be included in the crystal phase.Projection along the b axis of a portion of the crystal structure of sPBD12 containing a [mm] triad in the energy minimum.magnified imageProjection along the b axis of a portion of the crystal structure of sPBD12 containing a [mm] triad in the energy minimum.