bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced adhesion of blood cells to biodegradable polymers by introducing phosphorylcholine moieties
Authors: Iwasaki Yasuhiko , Tojo Yoko , Kurosaki Tomoyuki , Nakabayashi Nobuo 
Published: May 2003

AbstractAliphatic polyesters are believed to be good biocompatible polymers for tissue engineering because of their biodegradability and nontoxicity of the degradated products. However, it is necessary to reduce the nonspecific protein adsorption for the application of biodegradable polymers to drug delivery systems or antiadhesive membranes. We hypothesized that novel biodegradable polymers could be synthesized by introducing phosphorylcholine moieties into aliphatic polyesters. The L‐lactide was polymerized in the presence of L‐α‐glycelophosphorylcholine (LGPC) using stannous octate as the catalyst. The molecular weight and crystallinity of poly(L‐lactide) (PLLA)‐based phospholipid polymers (PLLA‐PC) decreased with an increase in the composition of the LGPC unit in the PLLA‐PC. The hydrolysis of the PLLA‐PC was evaluated by soaking the polymer membranes in a phosphate buffer solution. The rate of weight loss was increased with increasing the LGPC units in PLLA‐PC. The surface analysis of the membranes using an X‐ray photoelectron microscope showed the composition of phosphorylcoline groups on the surface. The amount of adsorbed protein and adherent blood cell on the polymer surface was decreased with introducing LGPC unit. PLLA‐PC is a promising biodegradable polymer having blood compatibility and antiadhesive property. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 164–169, 2003
Coaxial double‐tubular compliant arterial graft prosthesis: Time‐dependent morphogenesis and compliance changes after implantation
Authors: Sonoda Hiromichi , Takamizawa Keiichi , Nakayama Yasuhide , Yasui Hisataka , Matsuda Takehisa 
Published: May 2003

AbstractIn order to reduce the compliance mismatch between the native artery and the artificial graft, we have developed a coaxial double‐tubular compliant graft, using multiply micropored segmented polyurethane (SPU) thin films, which mimics the relationship between the intraluminal pressure and vessel internal diameter (P‐D) of the native artery (termed “J” curve). The graft was coaxially assembled by inserting a high‐compliance inner tube with a heparin‐immobilized photocured gelatin coating layer into a low‐compliance outer tube with a photocured hydrophilic polymer coating layer. Twenty‐eight coaxial double‐tubular compliant grafts were implanted into the canine common carotid arteries in an end‐to‐end fashion for up to 12 months. The overall patency rate was 86% (24/28), and neither rupture nor aneurysmal formation was observed. A neoarterial wall was formed via transanastomotic and transmural tissue ingrowth, resulting in neoarterial tissue formation on the luminal surface and into the intertubular space of the double‐tubular graft, accompanied by mainly myofibroblasts and inflammatory cells in the early stage and endothelialization and collagen‐rich extracellular matrices in the late stage of implantation. Surrounding‐tissue adhesion with the outer tube was prevented by the hydrophilic polymer coating. Although the J curve of the implanted prototype model was preserved 1 month after implantation, the impaired J curves were observed because of tissue ingrowth and tissue adhesion between the outer surface of the inner tube and the surrounding tissues 3 and 6 months after implantation. At 12 months after implantation, however, the implanted coaxial double‐tubular graft exhibited high compliance due to biodegradation of the SPU films. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 170–181, 2003
Investigation of elasto‐mechanical properties of alginate microcapsules by scanning acoustic microscopy
Authors: Klemenz Albrecht , Schwinger Christian , Brandt Jörg , Kressler Jörg 
Published: May 2003

AbstractHigh‐frequency scanning acoustic microscopy (SAM) was used for investigation of acoustic impedance and 3D‐surface topography of full alginate microspheres that act as model of artificial biological cells. Elasto‐mechanical properties of the investigated specimens have been characterized by acoustic impedance. Mean surface impedance of microspheres (diameter: 300 μm) was measured with SAM at 900 MHz with a spatial resolution of 1.5 μm. The sensitivity and reproducibility of SAM had to be increased considerable to receive and quantify signals in the very low impedance region. The multilayer analysis method was used to get quantitative data of acoustic impedance with SAM at a microscopic level. 3D images show details of structure and surface topography. As a reference, bulk measurements were performed on full alginate cylinders. The acoustical impedance and the mechanical stiffness c11 were obtained from mass density and longitudinal ultrasound velocity at 6 MHz. The impedances received with both methods are in close agreement. The results demonstrate the SAM as a powerful tool for characterizing mechano‐elastical parameters as well as surface structure and topography of microspheres with high spatial resolution. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 237–243, 2003
Loss of chondroitin 6‐sulfate and hyaluronan from failed porcine bioprosthetic valves
Authors: Grande‐Allen K. Jane , Mako W. John , Calabro Anthony , Shi Yaling , Ratliff Norman B. , Vesely Ivan 
Published: May 2003

AbstractExplanted porcine bioprosthetic valves have a thinned spongiosa, partially because of an overall loss of glycosaminoglycans (GAGs). We measured the concentrations of specific GAG classes in explanted bioprosthetic valves (n = 14, implanted 12.0 ± 4.7 years) compared with glutaraldehyde‐fixed porcine controls. After extraction with NaOH, GAGs were analyzed using either a hexuronic acid assay or fluorophore‐assisted carbohydrate electrophoresis to quantify the individual GAG classes. The total GAG concentration in explants was 198 ± 95 pmol/mg wet weight—93% less than freshly fixed controls. Explants also contained altered proportions of the different GAG classes relative to controls. The proportions of hyaluronan and chondroitin/dermatan‐6‐sulfate were reduced from 39 to 7% and 34 to 18% of total GAGs, respectively. The predominant explant GAG class was chondroitin/dermatan‐4‐sulfate (proportion elevated from 14 to 70%). This GAG is commonly found in the collagen‐associated proteoglycan decorin, which is likely well crosslinked by glutaraldehyde. Chondroitin‐6‐sulfate is commonly found in the water‐ and hyaluronan‐binding proteoglycan versican, which is likely poorly crosslinked. The loss of versican and its associated water‐binding capacity is consistent with the thinned spongiosa. The resultant compromise of hydration, compressive resistance, and viscoelasticity may be responsible for the deterioration of the bioprosthesis in vivo. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 251–259, 2003
Human serum opsonization of orthopedic biomaterial particles: Protein‐binding and monocyte/macrophage activation in vitro
Authors: Sun Doo‐Hoon , Trindade Michael C. D. , Nakashima Yasuharu , Maloney William J. , Goodman Stuart B. , Schurman David J. , Smith R. Lane 
Published: May 2003

AbstractWear particles generated after total joint arthroplasty activate monocyte/macrophages and incite formation of a granulomatous periprosthetic tissue associated with bone loss and implant loosening. This study tested the hypothesis that selective opsonization of orthopedic implant biomaterial wear particles by human serum proteins influences monocyte/macrophage activation. Serum protein binding to metallic, polymeric, and ceramic particles was determined by one‐dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). Individual proteins bound to particles were subsequently identified using two‐dimensional SDS‐PAGE, microsequencing techniques, and SWISS‐PROT analysis. Effects of selective protein opsonization on particle‐induced monocyte/macrophage activation were assessed by quantification of interleukin‐1beta, interleukin‐6, and tumor necrosis factor‐alpha release. Results from one‐dimensional gel analyses revealed distinct serum protein‐binding patterns specific for each material tested. Two‐dimensional gel analysis together with amino acid sequencing of the prominent protein species confirmed the presence of albumin and alpha‐1‐antitrypsin bound to all particles tested. In contrast to the metallic particles, apolipoprotein was a major species associated with polymeric particles. Opsonization of PMMA particles with purified preparations of each of the identified proteins showed that albumin significantly enhanced particle‐induced monocyte/macrophage activation. These data confirm orthopedic biomaterial specific binding of human serum proteins and demonstrate that albumin exacerbates particle‐induced monocyte/macrophage activation. Alterations in the chemical and surface properties of orthopedic biomaterials to modulate protein interactions may improve implant longevity. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 290–298, 2003
Dissolution properties of calcium phosphate granules with different compositions in simulated body fluid
Authors: Monteiro Magna Maria , da Rocha Nilce Carbonel Campos , Rossi Alexandre Malta , de Almeida Soares Gloria 
Published: May 2003

AbstractCalcium phosphate granules were produced through the calcination of three hydroxyapatites (HAs) at 1150°C: nearly‐stoichiometric (NS‐HA), calcium‐deficient (CD‐HA), and carbonated (Carb‐HA). The characterization using scanning electron microscope (SEM), X‐ray diffraction (XRD), and Fourier‐transformed infrared spectroscopy (FT‐IR) showed that those granules exhibit strong differences in chemical composition, surface texture, and dissolution behavior. Sample dissolution in a simulated body fluid (SBF) and precipitation of a calcium phosphate layer on the granule surface were followed up for 7 days by chemical analysis of calcium content in SBF. After 80‐min reaction, precipitation of new calcium phosphate phases predominates over the dissolution of original granules. Comparison between SEM images and XRD/FT‐IR analysis revealed that the composition of the calcium phosphate layer and its precipitation rate depend on the HA composition and its heat treatment. Calcined carbonated apatite induces the precipitation of an octacalcium phosphate (OPC) layer, whereas a carbonated apatite layer is formed from calcined‐deficient HA. The calcined nearly‐stoichiometric HA exhibits low efficiency in producing carbonated apatite layer. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 299–305, 2003
Antibacterial characteristics of newly developed amphiphilic lipids and DNA–lipid complexes against bacteria
Authors: Inoue Y. , Fukushima T. , Hayakawa T. , Takeuchi H. , Kaminishi H. , Miyazaki K. , Okahata Y. 
Published: May 2003

AbstractThe purpose of this study was to investigate the antibacterial activity of newly developed amphiphilic lipids and DNA/lipid complexes against two types of oral bacteria and two types of hospital infection bacteria. Nine amphiphilic lipids were quantitatively prepared from the reaction of n‐alkyl alcohol, α‐amino acids, and p‐toluenesulfonic acid. Nine DNA–lipid complexes were prepared by the simple mixing of DNA and amphiphilic lipids. The DNA–lipid complexes were insoluble in water. The antibacterial activity of lipids and DNA–lipid complexes against Porphyromonas gingivalis, Streptococcus mutans, Staphylococcus aureus, and Pseudomonas aeruginosa were evaluated by the disk‐diffusion method. Seven artificial lipids showed antibacterial behavior; in particular, the lipids prepared from n‐decyl alcohol and glycine and from n‐decyl alcohol and L‐alanine showed antibacterial activity against the four bacterial strains used in this study. On the other hand, the lipids of glutamic acid derivatives did not show any antibacterial activity against the four bacteria strains except for the lipid with an n‐octyl group. Five DNA–lipid complexes also had an antibacterial effect. The complex prepared from DNA and glycine decyl ester p‐toluenesulfonic acid salt exhibited antibacterial activity against the four types of bacteria strains. In this study it was found that lipids and DNA–lipid complexes with a mono‐decyl group or a mono‐dodecyl group have more favorable antibacterial activity. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 203–208, 2003
Preparation, characterization, and in vitro release of gentamicin from coralline hydroxyapatite‐alginate composite microspheres
Authors: Sivakumar M. , Rao K. Panduranga 
Published: May 2003

AbstractIn this work, composite microspheres were prepared from bioactive ceramics such as coralline hydroxyapatite [Ca10(PO4)6(OH)2] granules, a biodegradable polymer, sodium alginate, and an antibiotic, gentamicin. Previously, we have shown a gentamicin release from coralline hydroxyapatite granules–chitosan composite microspheres. In the present investigation, we attempted to prepare composite microspheres containing coralline hydroxyapatite granules and sodium alginate by the dispersion polymerization technique with gentamicin incorporated by absorption method. The crystal structure of the composite microspheres was analyzed using X‐ray powder diffractometer. Fourier transform infrared spectra clearly indicated the presence of per‐acid of sodium alginate, phosphate, and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs showed that the composite microspheres were spherical in shape and porous in nature. The particle size of composite microspheres was analyzed, and the average size was found to be 15 microns. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in vitro release profile of gentamicin from composite microspheres showed near zero order patterns. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 222–228, 2003
High‐frequency interferon‐γ‐secreting splenocytes specific for murine cytomegalovirus immediate‐early‐1 (IE‐1) peptide 168YPHFMPTNL176 are insufficient to provide complete protection from viral challenge
Authors: Morley Peter J. , Ertl Peter F. , Sweet Clive 
Published: May 2003

AbstractInfection of Balb/c mice with murine cytomegalovirus (MCMV) has been used extensively as a model system with which to study host mechanisms of immunity to cytomegaloviruses. In this model, the cytotoxic T‐lymphocyte (CTL) response crucial for clearing infected cells is dominated by CTLs specific for the MCMV nonapeptide 168YPHFMPTNL176 encoded by the immediate‐early 1 (IE‐1) gene. The intradermal injection of plasmid pcDNA89 encoding IE‐1 has been shown to offer some protection from viral challenge. In the present studies, the protective efficacy of immunisation with pcDNA89 given by intradermal injection was compared with particle‐mediated DNA delivery (PMDD) and contrasted with that induced by injection with the K181 MCMV strain and with temperature‐sensitive mutants (tsm) derived from the K181 strain. Modest protection was afforded by pcDNA89 immunisation given by PMDD, but none was observed after intradermal injection. PMDD immunisation induced a frequency of 168YPHFMPTNL176‐specific interferon‐γ (IFN‐γ)‐secreting splenocytes, which was equivalent to that after K181 infection and significantly higher than tsm immunisation. Whereas tsm‐immunised mice were completely protected from MCMV challenge, PMDD‐immunised mice were only weakly protected. Tsm immunisation protected mice completely against challenge with natural isolates having sequence variation in the IE‐1 nonapeptide, while PMDD‐immunised mice were weakly protected from isolates encoding 168YPHFMPTNL176 and were not protected against isolates encoding 168YPHFMPPSL176 or 168YLDFMPPNL176. Thus, while IE‐1‐specific IFN‐γ‐secreting splenocytes do contribute to immunity from MCMV challenge, their presence in isolation is insufficient to provide complete protection and they may not be involved in the protection observed against MCMV isolates having IE‐1 sequence variation. J. Med. Virol. 69:240–250, 2003. © 2003 Wiley‐Liss, Inc.
Quantitative Epstein‐Barr virus (EBV) serology in lung transplant recipients with primary EBV infection and/or post‐transplant lymphoproliferative disease
Authors: Verschuuren Erik , van der Bij Wim , de Boer Wim , Timens Wim , Middeldorp Jaap , The T. Hauw 
Published: May 2003

AbstractThe Epstein‐Barr virus (EBV)‐specific antibody response was studied in lung transplant patients to assess their value in the diagnosis and prognosis of post‐transplant lymphoproliferative disease. Recently developed synthetic peptides representing Epstein‐Barr nuclear antigen‐1 (EBNA‐1), diffuse early antigen (EA(D)), and virus capsid antigen (VCA) were studied in a semiquantitative enzyme‐linked immunosorbent assay (ELISA) to study antibody patterns in 12 seronegative lung transplant patients, of whom four developed a post‐transplant lymphoproliferative disease, and seven seropositive lung transplant patients, all of whom developed a post‐transplant lymphoproliferative disease. Immunoblot technique was used as a control. All 12 EBV‐seronegative patients had a very limited antibody response that was restricted mainly to VCA antibodies. EA(D) antibodies became detectable in only two patients. Antibody response never preceded clinical diagnosis of post‐transplant lymphoproliferative disease in the four EBV‐seronegative patients who developed post‐transplant lymphoproliferative disease. In the seven seropositive lung transplant patients with post‐transplant lymphoproliferative disease, we found a rise in antibody titer in only two patients. Immunoblot analysis confirmed the serological results. In conclusion, EBV‐specific antibody patterns after lung transplantation are highly restricted and variable and of limited value for the diagnosis or prognosis of post‐transplant lymphoproliferative disease. J. Med. Virol. 69:258–266, 2003. © 2003 Wiley‐Liss, Inc.
Transcriptional inactivation of amphotropic murine leukemia virus replication in human cells
Authors: Ploss Martin , Berdel Bianca , Heber Ricarda , Reuss Frank U. 
Published: May 2003

AbstractAmphotropic murine leukemia virus (MLV) replicates in cells from various mammalian species including humans and is a potential contaminant in MLV vector preparations for human gene transfer studies. Because MLV replication proceeds through an RNA genome that is generated under the control of viral enhancer and promoter elements, vectors were developed that delete such elements during transduction to reduce the generation of replication‐competent virus. It was shown recently that replication of amphotropic MLV in certain human cells is possible without the 75 bp transcription enhancers. It is now demonstrated that enhancer‐independent replication requires functional elements within U3 and is repressed by an extended deletion in the U3 region comprising enhancers, promoter and flanking sequences. It is concluded that the transcriptional inactivation of amphotropic MLV in human cells requires the combined deletion of enhancers and of additional elements in U3. J. Med. Virol. 69:267–272, 2003. © 2003 Wiley‐Liss, Inc.
Molecular investigation of hepatitis E virus infection in patients with acute hepatitis in Kathmandu, Nepal
Authors: Shrestha Santosh Man , Shrestha Shobhana , Tsuda Fumio , Nishizawa Tsutomu , Gotanda Yuhko , Takeda Naokazu , Okamoto Hiroaki 
Published: May 2003

AbstractOne hundred fifty‐four consecutive patients with sporadic acute hepatitis, who were seen at a city hospital in the Kathmandu valley of Nepal in 1997, were studied. IgM antibodies to hepatitis A virus were detected in four patients (3%), IgM antibodies to hepatitis B core in four patients (3%), hepatitis B surface antigen in 20 (13%), and hepatitis C virus RNA in four patients (3%). IgM antibodies to hepatitis E virus (HEV) (anti‐HEV IgM) and HEV RNA were detected in 77 (50%) and 48 (31%), respectively. Consequently, 86 patients (56%) including nine HEV‐viremic patients without anti‐HEV IgM, were diagnosed with hepatitis E. The cause of hepatitis was not known in 53 patients (34%). All 48 HEV RNA‐positive samples were genotyped as 1, and subtyped further as 1a in 17 (35%), 1c in 29 (60%), and mixed infection of 1a and 1c in 2 (4%). A seasonal difference in the prevalence of HEV subtypes was recognized. Before the rainy season (January to July), both 1a and 1c isolates were found: the intrasubtypic difference was up to 9.0% and 1.7%, respectively, in the 412‐nucleotide sequence of open reading frame 2. During the rainy season (August), only 1c isolates (n = 17) with 99.5–100% identity were found; 13 of 17 isolates had the same sequence, being identical to the 3 isolates that emerged at the end of July. These results suggest that a particular HEV 1c strain spread widely during the rainy season and was implicated in a small epidemic in the Kathmandu valley in August 1997. J. Med. Virol. 69:207–214, 2003. © 2003 Wiley‐Liss, Inc.
Co‐circulation of two genotypes of measles virus and mutual change of the prevailing genotypes every few years in Osaka, Japan
Authors: Kubo Hideyuki , Iritani Nobuhiro , Seto Yoshiyuki 
Published: May 2003

AbstractGenotypes of 44 wild‐type measles virus (MV) strains isolated in Osaka, Japan, during 1997–2001, were determined based on phylogenetic analyses of a 456‐nt 3′ terminal nucleoprotein gene sequence with the reference MV strains designated by the World Health Organization. The wild‐type MV strains were classified into two genotypes, D3 and D5, recognized as indigenous in Japan. Six of 12 strains isolated in 1997 were classified into genotype D3 and the other 6 into D5. Eleven of 13 strains were D3, and 2 were D5 in 1998. There were no measles epidemics, and no strains were isolated in 1999. Nine of 10 strains were genotype D5, and only one was D3 in 2000, and 9 of 9 were D5 in 2001. These results indicate that the wild‐type MV strains classified into genotypes D3 and D5 co‐circulated without the complete change of the MV genotype in Osaka, except in 2001. Furthermore, the prevailing genotype was different between 1998 and 2000–2001. Together with a previous report about MV genotype in this area during 1993–1995, these results suggest that the mutual change of the prevailing wild‐type MV genotypes between D3 and D5 occurs every few years in Osaka, Japan. J. Med. Virol. 69:273–278, 2003. © 2003 Wiley‐Liss, Inc.