bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteomic analysis of Staphylococcus aureus biofilms grown in vitro on mechanical heart valve leaflets
Authors: Bénard Laetitia , Litzler Pierre‐Yves , Cosette Pascal , Lemeland Jean‐François , Jouenne Thierry , Junter Guy‐Alain 
Published: April 2008

AbstractThe in vitro colonization of three commercial heart valve leaflets by Staphylococcus aureus was investigated. The leaflets, made of pyrolytic carbon alloyed with or without silicon, displayed similar surface properties (wettability, roughness) and were readily colonized by S. aureus that formed patchy biofilms on the three supports. A proteomic approach was used to assess the physiological status of biofilm populations by comparing their protein maps to those of bacteria cultured as free cells in the presence or absence of biofilm substratum. Principal component analysis (PCA) revealed, for each tested leaflet, statistical relationships between the protein maps of the biofilm and free‐floating microbial populations. A spot‐by‐spot comparison of protein levels on two‐dimensional electropherograms showed that many proteins were accumulated or underproduced by microbial populations grown in the presence of a leaflet compared with protein levels in control free populations. The number of accumulated proteins was noticeably higher than that of underproduced polypeptides. This protein overproduction was emphasized in biofilm populations. Several proteins, some of which were identified, were differentially produced by both surface‐associated planktonic and biofilm‐grown cell populations compared with control free‐cell ones cultured in the absence of leaflet, whatever the leaflet tested. The potential of this proteomic approach for fighting against microbial adhesion and biofilm formation is discussed. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
PLGA doping of PCL affects the plastic potential of human mesenchymal stem cells, both in the presence and absence of biological stimuli
Authors: Curran J. M. , Tang Z. , Hunt J. A. 
Published: April 2008

AbstractA range of poly ϵ‐caprolactone (PCL) films mixed/doped with poly(lactide‐co‐glycolide) (PLGA) (65:35) in 0, 10, 20, and 30 wt % were produced, sterilized using ethylene oxide, and analyzed using FTIR. Characterized human mesenchymal stem cells (hMSCs) were cultured in contact with the materials in basal, chondrogenic, and osteogenic medium for time periods up to 28 days, to determine if the materials could induce differentiation of MSC both in the presence and absence of biological stimuli. Viable cell adhesion was analyzed under all conditions. Collagen I, collagen II, sox‐9, osteocalcin, osteopontin, osteonectin, and CBFA1 were evaluated at both the mRNA (real‐time PCR) and protein production levels (fluorescent immunohistochemistry) and used to identify cell differentiation. Pure PCL and PCL mixed with PLGA demonstrated a chondrogenic potential. Only PCL 8 (80 wt % PCL, 20 wt % PLGA) facilitated osteogenic differentiation of MSCs under osteogenic conditions. This was attributed to the increased hydrophilic nature of the surface allowing sufficient homogeneous cell attachment and the formation of filamentous F‐actin in the cells, allowing osteogenic differentiation. Of all materials tested, PCL 7 (70 wt % PCL, 30 wt % PLGA) demonstrated the greatest chondrogenic differentiation potential under basal and stimulated conditions at both the mRNA and protein production level. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Recombinant human bone morphogenetic protein‐2/atelocollagen composite as a new material for ossicular reconstruction
Authors: Takeuchi Ayako , Tsujigiwa Hidetsugu , Murakami Jun , Kawasaki Akihiro , Takeda Yasushi , Fukushima Kunihiro , Rodriguez Andrea P. , Nagatsuka Hitoshi , Yamada Masao , Nishizaki Kazunori 
Published: April 2008

AbstractOssicular reconstruction is the rebuilding of the damaged middle ear. There are many different prosthesis and techniques used to reconstruct the middle ear ossicles. However, precision in the surgical procedures and prostheses used for ossiculoplasty are still imperfect. The objective of this study was to evaluate the potential of recombinant human bone morphogenetic protein‐2 (rhBMP‐2)/ atelocollagen composite for ossicular reconstruction implanted in the tympanic cavity of rat. The ossicles were extirpated by perforating the tympanic membranes of rats. rhBMP‐2/atelocollagen composite was implanted as substitute of ossicles in intimate contact with the tympanic membrane. Composites were subjected to histological, immunohistochemical, and radiological examination. To evaluate the auditory function, auditory brainstem response (ABR) was measured. rhBMP‐2/atelocollagen composites showed good stability and durability without any inflammatory reaction within the tympanic cavity. The process of new bone formation was similar to intramembranous ossification. They also demonstrated that the hearing ability was re‐established by ABR threshold shifts. rhBMP‐2/atelocollagen composite exhibited excellent potential for ossicular reconstruction, maintaining their vibratory function. This ossicular tissue engineering may be considered as a future therapeutic strategy for ossiculoplasty. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Controlled release of bisphosphonate from a calcium phosphate biomaterial inhibits osteoclastic resorption in vitro
Authors: Faucheux C. , Verron E. , Soueidan A. , Josse S. , Arshad M. D. , Janvier P. , Pilet P. , Bouler J. M. , Bujoli B. , Guicheux J. 
Published: April 2008

AbstractCalcium phosphate biomaterials such as calcium deficient apatite (CDA) have been contemplated as carrier for delivery of bisphosphonate in bone tissues. In the present work, we have investigated the in vitro biological properties of Zoledronate‐loaded CDA. CDA was loaded with zoledronate according to a previously described coating process. 31P MAS NMR spectra demonstrated the effective loading of zoledronate onto CDA. Using 14C labeled zoledronate, we then demonstrated the in vitro release of zoledronate from CDA. In a first set of experiments, we confirmed that Zoledronate reduced the number of TRAP‐, vitronectin receptor‐, and F‐actin ring‐positive cells as well as the resorption activity of osteoclasts obtained from a total rabbit bone cell culture. Interestingly, Zoledronate‐loaded CDA and its extractive solutions decreased the osteoclastic resorption. Finally, zoledronate‐loaded CDA did not affect the viability and alkaline phosphatase activity of primary osteoblastic cells. These data demonstrate that CDA is effective for loading and release of zoledronate. The released zoledronate inhibited osteoclastic resorption without affecting osteoblasts. Our findings therefore suggest that such a drug delivery system would allow an increase in the efficiency of bisphosphonates by being locally available. Further experiments are now required to evaluate the in vivo antiresorptive activity of this concept. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Extremal functions for rooted minors
Authors: Wollan Paul 
Published: April 2008

AbstractThe graph G contains a graph H as a minor if there exist pairwise disjoint sets {Si ⊆ V(G)|i = 1,…,|V(H)|} such that for every i, G[Si] is a connected subgraph and for every edge uv in H, there exists an edge of G with one end in Su and the other end in Sv. A rooted H minor in G is a minor where each Si of the minor contains a predetermined xi ∈ V(G). We prove that if the constant c is such that every graph on n vertices with cn edges contains an H minor, then every |V(H)|‐connected graph G with (9c + 26,833|V(H)|)|V(G)| edges contains a rooted H minor for every choice of vertices {x1,…,x|V(H)|} ⊆ V(G). The proof methodology is sufficiently robust to find the exact extremal function for an infinite family of rooted bipartite minors previously studied by Jørgensen, Kawarabayashi, and Böhme and Mohar. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:159–178, 2008
Gene expression profiles of human chondrocytes during passaged monolayer cultivation
Authors: Lin Zhen , Fitzgerald Jonathan B. , Xu Jiake , Willers Craig , Wood David , Grodzinsky Alan J. , Zheng Ming H. 
Published: April 2008

AbstractChondrocyte phenotype has been shown to dedifferentiate during passaged monolayer cultivation. Hence, we have investigated the expression profile of 27 chondrocyte‐associated genes from both osteoarthritic cartilage tissue and healthy passaged human articular chondrocytes by quantitative real‐time PCR. Our results indicate that the gene expression levels of matrix proteins and proteases in chondrocytes from monolayer culture decrease compared with those from cartilage tissue, while monolayer cultured chondrocytes from normal and osteoarthritic cartilage exhibit similar gene expression patterns. However, chondrocytic gene expression profiles were differentially altered at various stages of passage. The expression of the matrix proteins aggrecan, type II collagen, and fibromodulin inversely correlated with increasing passage number, while fibronectin and link protein exhibited a marked increase with passage. The expression of matrix proteinases MMP‐3/9/13 and ADAMTS‐4/5 decreased with passage, whereas proteinase inhibitors TIMP‐2/3 were elevated. The cytokine IL‐1 also showed increased expression with monolayer chondrocyte culture, while IGF‐1 expression levels were diminished. No significant changes in TGF‐β, or the chondrogenic transcription factors Sox‐9, c‐fos, or c‐jun were observed. Our data indicates that cultured chondrocytes undergo dedifferentiation during monolayer culture, although the gene expression level of transcription factors necessary for chondrogenesis remains unchanged. This data may prove important for the future development of more specific and efficacious cultivation techniques for human articular chondrocyte‐based therapies. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1230–1237, 2008
Age and pattern of the onset of differential growth among growth plates in rats
Authors: Wilsman Norman J. , Bernardini Elizabeth S. , Leiferman Ellen , Noonan Ken , Farnum Cornelia E. 
Published: April 2008

AbstractDifferential growth is the phenomenon whereby growth plates in the same individual at the same time all have uniquely different axial growth velocities. Differential growth is clearly present in the adolescent skeleton. In this study we ask two questions. When and by what pattern does the phenomenon of differential growth begin? Second, to what extent are the development of differential growth velocities correlated with changes in hypertrophic chondrocyte volume and/or with changes in chondrocytic production/turnover? Four growth plates (proximal and distal radial; proximal and distal tibial) were studied at 24 different time points in Long‐Evans rats between the 17th gestational day (when differential growth does not exist) and postnatal day 27 (when differential growth is well established). Growth velocities were measured using fluorochrome labeling. Using stereological methodology, multiple chondrocytic kinetic parameters were measured for all growth plates. Elongation of the proximal radial growth plate decreases relative to elongation in the other three growth plates in the late fetal phase. Differential growth is fully expressed at postnatal day 13 when the other three growth plates start to decrease daily elongation at different rates. Differential growth is primarily associated with differences in hypertrophic cell volume manifested when growth deceleration occurs. This study also illustrates that differential growth is superimposed on systemic regulators that affect all growth plates simultaneously. The most dramatic illustration of this is the sharp decline in growth velocity in all four growth plates that occurs perinatally. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1457–1465, 2008
Dexamethasone modulates BMP‐2 effects on mesenchymal stem cells in vitro
Authors: Jäger Marcus , Fischer Johannes , Dohrn Wiebke , Li Xinning , Ayers David C. , Czibere Akos , Prall Wolf Christian , Lensing‐Höhn Sabine , Krauspe Rüdiger 
Published: April 2008

AbstractDexamethasone/ascorbic acid/glycerolphosphate (DAG) and bone morphogenic protein (BMP)‐2 are potent agents in cell proliferation and differentiation pathways. This study investigates the in vitro interactions between dexamethasone and BMP‐2 for an osteoblastic differentiation of mesenchymal stem cells (MSCs). Bone marrow‐derived human MSCs were cultured with DAG (group A), BMP‐2 + DAG (group B), and DAG + BMP‐2 combined with a porous collagen I/III scaffold (group C). RT‐PCR, ELISA, immuncytochemical stainings and flow cytometry analysis served to evaluate the osteogenic‐promoting potency of each of the above conditions in terms of cell morphology/viability, antigen presentation, and gene expression. DAG induced collagen I secretion from MSCs, which was further increased by the combination of DAG + BMP‐2. In comparison, the collagen scaffold and the control samples showed no significant influence on collagen I secretion of MSCs. DAG stimulation of MSCs led also to a steady but not significant increase of BMP‐2 level. A DAG and more, a DAG + BMP‐2, stimulation increased the number of mesenchymal cells (CD105+/CD73+). All samples showed mRNA of ALP, osteopontin, Runx2, Twist 1 and 2, Notch‐1/2, osteonectin, osteocalcin, BSP, and collagen‐A1 after 28 days of in vitro culture. Culture media of all samples showed a decrease in Ca2+and POconcentration, whereas a collagen‐I‐peak only occurred at day 28 in DAG‐ and DAG + BMP‐2‐stimulated bone marrow cells. In conclusion, BMP‐2 enhances DAG‐induced osteogenic differentiation in mesenchymal bone marrow cells. Both agents interact in various ways and can modify osteoblastic bone formation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1440–1448, 2008
The influence of wear paths produced by hip replacement patients during normal walking on wear rates
Authors: Bennett Damien , Humphreys Lee , O'Brien Seamus , Kelly Connor , Orr John , Beverland David E. 
Published: April 2008

AbstractVariation in wear paths is known to greatly affect wear rates in vitro, with multidirectional paths producing much greater wear than unidirectional paths. This study investigated the relationship between multidirectional motion at the hip joint, as measured by aspect ratio, sliding distance, and wear rate for 164 hip replacements. Kinematic input from three‐dimensional gait analysis was used to determine the wear paths. Activity cycles were determined for a subgroup of 100 patients using a pedometer study, and the relationship between annual sliding distance and wear rate was analyzed. Poor correlations were found between both aspect ratio and sliding distance and wear rate for the larger group and between annual sliding distance and wear rate for the subgroup. However, patients who experienced a wear rate <0.08 mm/year showed a strong positive correlation between the combination of sliding distance, activity levels, and aspect ratio and wear rate (adjusted r2 = 55.4%). This group may represent those patients who experience conditions that most closely match those that prevail in simulator and laboratory tests. Although the shape of wear paths, their sliding distance, and the number of articulation cycles at the hip joint affect wear rates in simulator studies, this relationship was not seen in this clinical study. Other factors such as lubrication, loading conditions and roughness of the femoral head may influence the wear rate. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1210–1217, 2008
Pulsed electromagnetic fields enhance BMP‐2 dependent osteoblastic differentiation of human mesenchymal stem cells
Authors: Schwartz Z. , Simon B. J. , Duran M. A. , Barabino G. , Chaudhri R. , Boyan B. D. 
Published: April 2008

AbstractMesenchymal stem cells (MSCs) express an osteoblastic phenotype when treated with BMP‐2, and BMP‐2 is used clinically to induce bone formation although high doses are required. Pulsed electromagnetic fields (PEMF) also promote osteogenesis in vivo, in part through direct action on osteoblasts. We tested the hypothesis that PEMF enhances osteogenesis of MSCs in the presence of an inductive stimulus like BMP‐2. Confluent cultures of human MSCs were grown on calcium phosphate disks and were treated with osteogenic media (OM), OM containing 40 ng/mL rhBMP‐2, OM + PEMF (8 h/day), or OM + BMP‐2 + PEMF. MSCs demonstrated minor increases in alkaline phosphatase (ALP) during 24 days in culture and no change in osteocalcin. OM increased ALP and osteocalcin by day 6, but PEMF had no additional effect at any time. BMP‐2 was stimulatory over OM, and PEMF + BMP‐2 synergistically increased ALP and osteocalcin. PEMF also enhanced the effects of BMP‐2 on PGE2, latent and active TGF‐β1, and osteoprotegerin. Effects of PEMF on BMP‐2–treated cells were greatest at days 12 to 20. These results demonstrate that PEMF enhances osteogenic effects of BMP‐2 on MSCs cultured on calcium phosphate substrates, suggesting that PEMF will improve MSC response to BMP‐2 in vivo in a bone environment. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1250–1255, 2008
Muscle stabilization strategies in people with medial knee osteoarthritis: The effect of instability
Authors: Schmitt Laura C. , Rudolph Katherine S. 
Published: April 2008

AbstractThe sensation of knee instability (shifting, buckling. and giving way) is common in people with medial knee osteoarthritis (OA). Its influence on knee stabilization strategies is unknown. This study investigated the influence of knee instability on muscle activation during walking when knee stability was challenged. Twenty people with medial knee OA participated and were grouped as OA Stable (OAS) (n = 10) and OA Unstable (OAU) (n = 10) based on self‐reported knee instability during daily activities. Quadriceps strength, passive knee laxity, and varus alignment were assessed and related to knee instability and muscle cocontraction during walking when the support surface translated laterally. Few differences in knee joint kinematics between the groups were seen; however, there were pronounced differences in muscle activation. The OAU group used greater medial muscle cocontraction before, during, and following the lateral translation. Self‐reported knee instability predicted medial muscle cocontraction, but medial laxity and limb alignment did not. The higher muscle cocontraction used by the OAU subjects appears to be an ineffective strategy to stabilize the knee. Instability and high cocontraction can be detrimental to joint integrity, and should be the focus of future research. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1180–1185, 2008
The response of mineralizing culture systems to microtextured and polished titanium surfaces
Authors: Hacking S. Adam , Harvey Edward , Roughley Peter , Tanzer Michael , Bobyn John 
Published: April 2008

AbstractThe surface texture of titanium has a predictable effect on peri‐implant tissue formation in vivo. When implanted in an osseous environment, smooth surfaces (Ra < 0.5 mm) are generally apposed by fibrous tissue and textured surfaces (Ra > 1.0 mm) are generally apposed by osseous tissue. Thus in vitro study assessed the mineralization and proliferation response of TF274, MC3T3‐E1, murine femoral stromal cells and canine stromal cells to tissue culture plastic (Ra = 0.001 mm), polished (Ra = 0.01 mm) and irregularly textured (Ra = 3.26 mm) titanium surfaces. Amongst all culture systems, proliferation was significantly decreased on textured vs. smooth surfaces. Midway through the culture of the canine marrow cells, the cell layer detached from the tissue culture plastic and polished titanium surfaces. The TF274, MC3T3‐E1, murine femoral stromal cell systems formed a mineralized matrix on the tissue culture plastic and polished titanium surfaces which was not observed with the canine stromal cell system. Compared to the tissue culture plastic and polished titanium surfaces, matrix mineralization was significantly reduced on the textured titanium surfaces for the TF274, MC3T3‐E1, murine femoral stromal systems, a result which was differed significantly in comparison to the canine stromal system. These results were surprising given the large number of reports concerning the in vivo response to titanium in clinical and pre‐clinical studies. Further work is required to determine if the TF274, MC3T3‐E1 and murine femoral stromal systems are suitable for the in vitro investigation of the effects of titanium surface texture on osteoblast activity. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1347–1354, 2008
Changes of selenium, copper, and zinc content in hair and serum of patients with idiopathic scoliosis
Authors: Dastych M. , Cienciala J. , Krbec M. 
Published: April 2008

AbstractOur work aimed at extending the search for abnormalities of trace elements in patients with idiopathic scoliosis to the content of zinc (Zn), copper (Cu), and selenium (Se) in these subject's hair and serum. A total of 59 patients (54 girls and 4 boys) with idiopathic scoliosis, aged 13 on the average (range, 10–18 years), were examined. The degree of spine curvature deformity ranged between 12° and 82°. The hair of scoliotic patients under examination showed significantly increased content of zinc 263 ± 108 µg/g (p < 0.01) and copper 46.2 ± 37.1 µg/g (p < 0.01), and decreased content of selenium 0.194 ± 0.114 µg/g (p < 0.01) in comparison with the control group. In scoliotic patients, the Cu/Zn ratio in hair (0.186 ± 0.139) did not differ significantly from the values found in the probands of the control group (0.115 ± 0.09). The Cu/Se ratio in this group of patients (254.9 ± 215.9) was significantly higher (p < 0.001) due to a higher Cu value and a lower Se value in comparison with the controls (47.9 ± 23.7). In comparison with controls, the serum selenium concentration in the group of scoliotic patients was significantly decreased p < 0.05 (0.74 ± 0.13 µmol/L and 0.98 ± 0.12 µmol/L). Various changes in the content of trace elements in biological samples taken from patients with idiopathic scoliosis are not accidental. What might bring about a shift in our knowledge is speciation of various forms of trace elements in the organism in relation to idiopathic scoliosis. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1279–1282, 2008