bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of bio‐compatibility via specific interactions in polyesters modified with a bio‐resourceful macromolecular ester containing polyphenol groups
Authors: Yen Kai‐Cheng , Mandal Tarun K. , Woo E.M. 
Published: November 2007

AbstractSpecific interactions and miscibility are demonstrated in a series of binary miscible blend comprising of bio‐compatible/biodegradable polyesters, such as poly(ϵ‐caprolactone) (PCL), poly(ethylene adipate) (PEA), or poly (butylene adipate) (PBA), and a macromolecular ester with polyphenol groups, tannic acid (TA). Thermal analysis and infrared spectroscopy were used for proving existence of favorable interactions, and polarized‐light optical microscopy was used for characterizing the changes in crystal growth. The appearance of a single composition‐dependent glass transition temperature (Tg) observed by differential scanning calorimetry (DSC) indicated that TA is miscible with PCL, PBA, and PEA, respectively, over the entire range of compositions. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of specific intermolecular hydrogen bonding interactions between the carbonyl groups of polyesters and the phenolic hydroxyl groups of TA. The blend Tg's generally exhibited various extents of positive‐then‐negative deviation from linearity with the compositions. The Tg‐composition relationships for three blend systems could all be fitted by the Kwei equation with large negative q values of −80 to −110 for different polyesters. Significant effects by TA on the spherulitic crystallization growth in the polyester/TA blends were also discussed to support the miscibility and strong interactions. Overall, the behavior of blends of polyesters with TA is similar to that of blends of polyesters with poly(vinyl p‐phenol) (PVPh) that have been more widely studied and reported. However, TA is naturally bio‐resourceful, bio‐compatible, and bio‐degradable but PVPh is not. Synergism of miscibility, natural bio‐compatibility, and biodegradability in these blends by introducing naturally biodegradable macromolecules such as TA may offer greater potential in intended applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Pre‐treatment of synthetic elastomeric scaffolds by cardiac fibroblasts improves engineered heart tissue
Authors: Radisic Milica , Park Hyoungshin , Martens Timothy P. , Salazar‐Lazaro Johanna E. , Geng Wenliang , Wang Yadong , Langer Robert , Freed Lisa E. , Vunjak‐Novakovic Gordana 
Published: November 2007

AbstractNative myocardium consists of several cell types, of which approximately one‐third are myocytes and most of the nonmyocytes are fibroblasts. By analogy with monolayer culture in which fibroblasts were removed to prevent overgrowth, early attempts to engineer myocardium utilized cell populations enriched for cardiac myocytes (CMs; ∼80–90% of total cells). We hypothesized that the pre‐treatment of synthetic elastomeric scaffolds with cardiac fibroblasts (CFs) will enhance the functional assembly of the engineered cardiac constructs by creating an environment supportive of cardiomyocyte attachment and function. Cells isolated from neonatal rat ventricles were prepared to form three distinct populations: rapidly plating cells identified as CFs, slowly plating cells identified as CMs, and unseparated initial population of cells (US). The cell fractions (3 × 106 cells total) were seeded into poly(glycerol sebacate) scaffolds (highly porous discs, 5 mm in diameter × 2‐mm thick) using Matrigel™, either separately (CM or CF), concurrently (US), or sequentially (CF pre‐treatment followed by CM culture, CF + CM), and cultured in spinner flasks. The CF + CM group had the highest amplitude of contraction and the lowest excitation threshold, superior DNA content, and higher glucose consumption rate. The CF + CM group exhibited compact 100‐ to 200‐μm thick layers of elongated myocytes aligned in parallel over layers of collagen‐producing fibroblasts, while US and CM groups exhibited scattered and poorly elongated myocytes. The sequential co‐culture of CF and CM on a synthetic elastomer scaffold thus created an environment supportive of cardiomyocyte attachment, differentiation, and contractile function, presumably due to scaffold conditioning by cultured fibroblasts. When implanted over the infarcted myocardium in a nude rat model, cell‐free poly(glycerol sebacate) remained at the ventricular wall after 2 weeks of in vivo, and was vascularized. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Oscillatory perfusion seeding and culturing of osteoblast‐like cells on porous beta‐tricalcium phosphate scaffolds
Authors: Du Dajiang , Furukawa Katsuko , Ushida Takashi 
Published: November 2007

AbstractPerfusion culture systems have proven to be effective bioreactors for constructing tissue engineered bone in vitro, but existing circuit‐based perfusion systems are complicated and costly for conditioned culture due to the large medium volume required. A compact perfusion system for artificial bone fabrication using oscillatory flow is described here. Mouse osteoblast‐like MC 3T3‐E1 cells were seeded at 1.5 × 106 cells/100 μL and cultured for 6 days in porous ceramic beta‐tricalcium phosphate scaffolds (10 mm in diameter, 8 mm in height) by only 1.5 mL culture media per scaffold. The seeding efficiency, cell proliferation, distribution and viability, and promotion of early osteogenesis by both a static and an oscillatory perfusion method were evaluated. The oscillatory perfusion method generated higher seeding efficiency, alkaline phosphatase activity, and scaffold cellularity (by DNA content) after 6 days of culture. Stereomicroscopic observation of 3(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide staining and Calcein‐AM/propidium iodide double staining also demonstrated homogeneous seeding, proliferation, and viability of cells throughout the scaffolds in the oscillatory perfusion system. By contrast, the static culture yielded polarized seeding and proliferation favoring the outer and upper scaffold surfaces, with only dead cells in the center of the scaffolds. Thus, these results suggest that the oscillatory flow condition not only allow a better seeding efficiency and homogeneity, but also facilitates uniform culture and early osteogenic differentiation. The oscillatory perfusion system could be a simple and effective bioreactor for bone tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Bacterial adhesion and osteoblast function on titanium with surface‐grafted chitosan and immobilized RGD peptide
Authors: Shi Zhilong , Neoh K. G. , Kang E. T. , Poh Chyekhoon , Wang W. 
Published: November 2007

AbstractBiomaterials‐associated infections remain a source of serious complications in modern medicine. When a biomaterial is implanted in the body, the result of successful tissue integration or implant infection depends on the race for the surface between bacteria and tissue cells. One promising strategy to reduce the incidence of infection is the functionalization of the biomaterial surface to inhibit bacterial adhesion and encourage the growth of cells. In this in vitro study, the surface of titanium alloy substrates was first functionalized by covalently grafted chitosan (CS). The cell‐adhesive Arg‐Gly‐Asp (RGD) peptide was then immobilized on the CS‐grafted surface through covalent binding of peptide to the free NH2 groups of CS. Both these functionalized surfaces showed a decrease in adhesion of Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) compared with the pristine substrate. A significant increase in osteoblast cell attachment, proliferation, and alkaline phosphatase activity was observed on the surface with the immobilized Arg‐Gly‐Asp peptide. Thus, utilizing surface‐grafted chitosan in conjunction with the cell‐adhesive peptide to modify the metal surface provides a promising means for enhancing tissue integration of implants by reducing bacterial adhesion and promoting osteoblast functions. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Hemocompatible albumin‐heparin coatings prepared by the layer‐by‐layer technique. The effect of layer ordering on thrombin inhibition and platelet adhesion
Authors: Houska Milan , Brynda Eduard , Solovyev Andrey , Broučková Adéla , Křížová Petra , Vaníčková Martina , Dyr Jan E. 
Published: November 2007

AbstractUsing the layer‐by‐layer technique, ELISA polystyrene plates were coated with multilayer assemblies of albumin with various heparins or with multilayer assemblies of albumin. The coatings containing heparin were tested for their ability to potentiate thrombin inhibition by antithrombin and its dependence on the layer arrangement. The order of activities of surface bound heparins matched their order in solution; however their activity was reduced to less than 10% due to binding. The increasing number of layers increased the activity of the coatings suggesting that heparin inside the assemblies is available for the interaction. The albumin‐heparin assemblies overcoated with albumin layers preserved about half of heparin activity. Platelets adhered in similar amounts to albumin‐heparin and albumin coatings; however, in both cases platelets adhered more to single layer than to multilayer coatings. The adhesion of platelets to single layer coatings was also affected by the crosslinking of the coatings; more platelets adhered to less crosslinked single layer coatings while multilayer coatings remained essentially unaffected by crosslinking. If the coatings were dried and reswollen, a substantial number of platelets adhered to the reconditioned single layer coatings but the two layer coatings were affected much less and the adhesion of platelets to the coatings with three layers was close to normal. A minimum of three albumin‐heparin or albumin layers is apparently required to shield the underlying surface and to achieve proper functioning of the coatings. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Potential of baboon endothelial progenitor cells for tissue engineered vascular grafts
Authors: Hinds Monica T. , Ma MinHui , Tran Noi , Ensley Ann E. , Kladakis Stephanie M. , Vartanian Keri B. , Markway Brandon D. , Nerem Robert M. , Hanson Stephen R. 
Published: November 2007

AbstractThrombosis and intimal hyperplasia limit the usefulness of small caliber vascular grafts. While some improvements have been reported for grafts seeded with mature endothelial cells (EC), the harvesting of ECs from autologous sources, for example, veins or adipose tissue, remains problematic. More recently, endothelial progenitor cells (EPCs) have been considered a promising source of ECs because EPCs can be readily isolated from whole blood then rapidly expanded in vitro. Additionally, EPCs are increasingly recognized to play important roles in hemostasis, angiogenesis, and arterial injury repair. However, the characterization of EPCs in relevant animal models remains poorly defined. Accordingly, we have characterized the isolation, growth, and functional characteristics of Baboon EPCs (BaEPCs) to evaluate their potential for an autologous cell source for tissue engineered vascular grafts. BaEPCs were successfully cultured from the peripheral blood with an average population doubling time of 1.17 ± 0.43 days. While the BaEPCs were positive for typical EC markers of vWF, CD31, VE‐cadherin, VEGF‐R2, Thrombomodulin, and E‐selectin, there was reduced eNOS expression. The BaEPCs cell body and actin filaments align in the direction of flow typical of mature ECs. Thus while the lack of eNOS expression is worthy of investigation, EPCs are an attractive cell source for tissue engineered vascular grafts and the baboon model has great potential for continuing evaluations of these cells. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Solubilization and bioconjugation of QDs and their application in cell imaging
Authors: Wang Hai‐Qiao , Zhang Hai‐Li , Li Xiu‐Qing , Wang Jian‐Hao , Huang Zhen‐Li , Zhao Yuan‐Di 
Published: November 2007

AbstractQuantum dot (QD) solubilization, conjugation with biomolecules, column purification, and labeling of human HepG2 cells with transferrin‐QD (Tf‐QD) conjugates are reported in detail in this article. Water‐soluble QDs (WQDs) were obtained using sodium thiolycolate to replace the surface ligand tri‐n‐octylphosphine oxide (TOPO) on the surface of oil‐soluble QDs, and Tf‐QD conjugates were produced by coupling Tf to WQD. The resulting Tf‐QDs were characterized by UV and luminescence spectrophotometry and purified by Sephadex column. The results indicate that Tf has been conjugated to QD successfully. Based on transferrin/transferrin‐receptor‐mediated delivery system, the Tf‐QD conjugates were used to label human HepG2 cells. After a short incubation, the QDs were mainly localized to the membrane of cells. After 12‐h incubation, QDs appear mainly in the cytoplasm portion. However, QDs were not found in the nucleus of the cells. Furthermore, the fluorescence intensity of QDs in the cells reduces gradually over time, and fluorescence cannot be observed after 10 days. However, the growth of the labeled cells was not markedly affected by the toxicity of QDs, and they are alive for 10 days. These results can be used for further application of QDs in bioscience. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
In vitro engineering of a palatal mucosa equivalent with acellular porcine dermal matrix
Authors: Xiong Xuepeng , Zhao Yifang , Zhang Wei , Xie Weiguo , He Sangang 
Published: November 2007

AbstractThe objective of this study was to develop a palatal mucosa equivalent composed of multilayered oral keratinocytes grown on the acellular porcine dermal matrix. Acellular porcine dermal matrix was prepared through a series of procedures and assessed by histological, immunohistochemical, and scanning electron microscopy examination. The palatal mucosa equivalent was fabricated by seeding oral keratinocytes, which cultured from human palate mucosa, onto the acellular dermal matrix. After 4 days submerged in medium, this composite was raised to the air–liquid interface for another 7 or 14 days of cultivation. The results demonstrated the processed porcine dermal matrix was totally cell‐free. The resultant palatal mucosa equivalent showed a multilayered oral epithelium that had been formed, and the number of cell layers was correlated with the culture period at the air–liquid interface. Oral keratinocytes infiltrated into the empty hair follicles of the acellular porcine dermal matrix and formed an anchor‐like structure, which exhibited resemblance to the rete ridges of the native palate mucosa. Immunohistochemical staining for CK10/13, CK19, Ki‐67 nuclear antigen, and Heparan sulphate indicated the cultured palatal mucosa equivalent shared the same characteristics with that of the native palate mucosa. In conclusion, our fabricated palatal mucosa equivalent exhibited the characteristics of the native counterpart, and this equivalent might be useful for recovery of the wounds in the palate secondary to palatoplasty. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Polyubiquitylation of PARP‐1 through ubiquitin K48 is modulated by activated DNA, NAD+, and dipeptides
Authors: Wang Tao , Simbulan‐Rosenthal Cynthia M. , Smulson Mark E. , Chock P. Boon , Yang David C.H. 
Published: November 2007

AbstractPoly(ADP‐ribose) polymerase‐1 (PARP‐1) is the most abundant and the best‐studied isoform of a family of enzymes that catalyze the polymerization of ADP‐ribose from NAD+ onto target proteins. PARP‐1 is well known to involve in DNA repair, genomic stability maintenance, transcription regulation, apoptosis, and necrosis. Polyubiquitylation targets proteins towards degradation and regulates cell cycle progression, transcription, and apoptosis. Here we report polyubiquitylation of PARP‐1 in mouse fibroblasts in the presence of proteasome inhibitor and in full‐length recombinant PARP‐1 in vitro under standard ubiquitylation assay conditions by immunoprecipitation and immunoblotting. Mutation of ubiquitin K48R but not ubiquitin K63R abolishes polyubiquitylation of PARP‐1, indicating that K48 of ubiquitin was used in the formation of polyubiquitin chain and that ubiquitylated PARP‐1 is likely destined for degradation. Full‐length PARP‐1 was ubiquitylated most likely at the N‐terminal 24 kDa domain of PARP‐1 as suggested by the inhibition of ubiquitylation by activated DNA and the absence of polyubiquitin in the C‐terminal 89 kDa PARP‐1 derived from caspase‐catalyzed cleavage. NAD+ inhibited ubiquitylation of PARP‐1, while dipeptides ArgAla and LeuAla enhanced ubiquitylation of PARP‐1. ATP inhibited the synthesis of poly(ADP‐ribose) by PARP‐1 and affinity purified polyubiquitylated PARP‐1 was active in PAR synthesis. The results suggest polyubiquitylation of PARP‐1 could regulate poly(ADP‐ribosyl)ation of nuclear proteins by PARP‐1 and consequently apoptosis and PARP‐1 regulated cellular processes through ubiquitin‐dependent degradation pathways. J. Cell. Biochem. 104: 318–328, 2008. © 2007 Wiley‐Liss, Inc.
Detection and characterization of vascular endothelial growth factors and their receptors in a series of angiosarcomas
Authors: Itakura Eijun , Yamamoto Hidetaka , Oda Yoshinao , Tsuneyoshi Masazumi 
Published: November 2007

AbstractBackgroundAngiosarcomas are malignant mesenchymal neoplasms, including sarcomas of presumptive vascular endothelial origin and sarcomas of probable lymphatic origin. It is, however, often difficult to determine whether they are from blood vascular or lymphatic endothelium. The majority of angiosarcomas are thought to originate from vascular endothelia and spread via bloodstream to lung, but lymphatic metastases can occur.MethodsWe investigated immunohistochemical expression of vascular endothelial growth factors (VEGF‐A, VEGF‐C) and their receptors (VEGFR‐1, VEGFR‐2, VEGFR‐3) in a series of 34 angiosarcomas.ResultsVEGF‐A was expressed by 32/34 (94%), VEGF‐C by 4/34 (12%), VEGFR‐1 by 32/34 (94%), VEGFR‐2 by 22/34 (65%), and VEGFR‐3 by 27/34 (79%). Patients who expressed low or no VEGFR‐2 showed a significantly unfavorable prognosis by log‐rank test (P = 0.010) and multivariate analysis (hazard ratio, 5.16; 95% CI, 1.40–19.04; P = 0.014). VEGFR‐1 and VEGFR‐3 were not significantly associated with patients' prognosis.ConclusionsVEGF‐A and VEGFR‐1 were detected in diverse subtypes of angiosarcomas. In cooperation, VEGF‐A and VEGF‐C are likely to be involved in the development of angiosarcoma associated with lymphedema. VEGF‐C expression may cause susceptibility to lymphatic metastasis through tumor lymphangiogenesis. Angiosarcoma of the scalp, which is traditionally considered as a true hemangiosarcoma, may include some cases of lymphatic origin. J. Surg. Oncol. 2008;97:74–81. © 2007 Wiley‐Liss, Inc.
Experimental Correlation between Mechanical Non‐Linearity in LAOS Flow and Capillary Flow Instabilities for Linear and Branched Commercial Polyethylenes
Authors: Filipe Susana , Vittorias Iakovos , Wilhelm Manfred 
Published: November 2007

AbstractAn experimental correlation between the non‐linear behaviour of commercial polyethylene melts in LAOS flow, and the pressure fluctuations associated with melt flow instabilities developed in capillary rheometry are presented. Polyethylene melts with enhanced non‐linear behaviour under LAOS conditions present larger pressure fluctuations during capillary extrusion, and consequently, larger surface distortions on the extrudate. The combination of both methods can be a tool to predict the development of melt flow instabilities in the extrusion process of polyethylene melts, and can elucidate their correlation with material structural properties ($\overline M _{\rm w}$, MWD and topology).magnified image
Diabetes mellitus and female lower urinary tract symptoms: A review
Authors: Hill Simon R. , Fayyad Abdalla M. , Jones Geraint R. 
Published: November 2007

AbstractDiabetes mellitus (DM) has reached epidemic proportions world wide. Many chronic complications of DM, including neuropathy, retinopathy and nephropathy, have been well studied and although urologic complications have been recognized since 1935, little is known about DM as a pathophysiological risk factor for development of lower urinary tract symptoms (LUTS) in women. Diabetic nephropathy, a life‐threatening condition, has received considerable attention in the last few years. Diabetic cystopathy, on the other hand, has received far less attention despite having a significant impact on quality of life, and with significant individual health risks. Initial studies suggested that long standing DM causes paralysis of the detrusor muscle leading to voiding difficulties and this has been the received wisdom regarding diabetic cystopathy for many years. In this review, we discuss what is currently known about lower urinary tract function and urinary incontinence in diabetic females, with a critical analysis of the available evidence and suggest areas for future research. Neurourol. Urodynam. 27:362–367, 2008. © 2007 Wiley‐Liss, Inc.
Bladder voiding by combined high frequency electrical pudendal nerve block and sacral root stimulation
Authors: Boger Adam , Bhadra Narendra , Gustafson Kenneth J. 
Published: November 2007

AbstractAimsUncoordinated contraction of the external urethral sphincter is prevalent in individuals with spinal cord injury and can prevent bladder voiding. The aim of this study was to demonstrate that complete and reversible sinusoidal high frequency alternating current (HFAC) conduction block of the pudendal nerves (PN) can eliminate external urethral sphincter activation and produce low residual bladder voiding.MethodsIn four cats, tripolar nerve cuff electrodes were implanted bilaterally on both pudendal nerves and on both extradural S2 roots. Bladder and urethral pressures, bladder volumes and flow were recorded. Bilateral HFAC was applied to determine voltage and frequency parameters resulting in bilateral PN conduction block. Sacral root stimulation provided bladder activation. Randomized sets of voiding trials were conducted with and without HFAC PN block. Additional voiding trials were conducted following bilateral PN neurotomy to eliminate somatic sphincter resistance and provide an estimate of voiding with complete block.ResultsEffective bilateral PN block and voiding was obtained in three of four animals. Application of bilateral PN HFAC stimulation improved voiding from 2 ± 4% to 77 ± 18% of the initial bladder volume and significantly (P < 0.001) reduced maximum bladder pressure during voiding. Voiding in trials with PN block was not significantly different from voiding following PN neurotomy (82 ± 19%, P = 0.51).ConclusionsThese results demonstrate that bilateral HFAC block of the PN can produce effective voiding. Neural prostheses using this approach may provide an alternative method for producing micturition for people with spinal cord injury. Neurourol. Urodynam. 27:435–439, 2008. © 2007 Wiley‐Liss, Inc.