bluuebunny/crossref_metadata_2025 huggingface dataset:
Vascular endothelial growth factor and fibroblast growth factor 2 delivery from spinal cord bridges to enhance angiogenesis following injury
Authors: De Laporte Laura , des Rieux Anne , Tuinstra Hannah M. , Zelivyanskaya Marina L. , De Clerck Nora M. , Postnov Andrei A. , Préat Véronique , Shea Lonnie D.
Published: May 2011

The host response to spinal cord injury can lead to an ischemic environment that can induce cell death and limits cell transplantation approaches to promote spinal cord regeneration. Spinal cord bridges that provide a localized and sustained release of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF‐2) were investigated for their ability to promote angiogenesis and nerve growth within the injury. Bridges were fabricated by fusion of poly(lactide‐co‐glycolide) microspheres using a gas foaming/particulate leaching technique, and proteins were incorporated by encapsulation into the microspheres and/or mixing with the microspheres before foaming. Compared to the mixing method, encapsulation reduced the losses during leaching and had a slower protein release, while VEGF was released more rapidly than FGF‐2. In vivo implantation of bridges loaded with VEGF enhanced the levels of VEGF within the injury at 1 week, and bridges releasing VEGF and FGF‐2 increased the infiltration of endothelial cells and the formation of blood vessel at 6 weeks postimplantation. Additionally, substantial neurofilament staining was observed within the bridge; however, no significant difference was observed between bridges with or without protein. Bridges releasing angiogenic factors may provide an approach to overcome an ischemic environment that limits regeneration and cell transplantation‐based approaches. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Osteoinductivity of partially purified bovine, ostrich and emu bone morphogenetic proteins in vitro
Authors: Hu ZhenMing , Peel Sean A.F. , Lindholm Tom C. , Sàndor George K.B. , Clokie Cameron M. L. , Su Yan
Published: May 2011

The aim of this study was to observe the osteogenic activity of native bone morphogenetic proteins (BMPs) obtained from different species including bovine, ostrich and emu sources in order to compare mammalian and avian BMPs. Rat mesenchymal progenitor marrow stromal cells and pre‐osteoblastic C2C12 cell cultures, were exposed to the native BMPs and alkaline phosphatase (ALP) and creatine kinase (CK) levels were determined by assay. The results showed that the ALP activity in C2C12 cultures was elevated by bovine BMP by 2‐ to 10‐fold (p < 0.05‐0.001) from day 3 during 14 days. There were no significant differences in avian BMP related elevations of ALP activity except with ostrich BMPs at day 14 (p < 0.05). However, exposure of MSCs cultures to BMPs derived from bovine, ostrich or emu sources resulted in elevated ALP from day 3 (p < 0.05). Bovine BMP resulted in more ALP elevation than with either of the avian BMPs. All of BMPs elevated Creatine kinase (CK) activity from day 1 and climbed until peaking at day 7. Compared with control cultures, CK was elevated more with exposure to emu BMP and was more elevated with greater statistical significance than with bovine and ostrich BMP before day 5. These higher levels remained until day 14 (p < 0.05). The results of this study suggest that both bovine and avian BMPs are able to stimulate osteogenesis in mature osteoblasts in vitro. The strongest synergistic effect on osteogenesis was detected in cells stimulated with bovine BMP. Avian BMPs had lower effects on ALP and CK activity, emu BMP being more effective than ostrich BMP. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Structural surface changes and inflammatory responses against alginate‐based microcapsules after exposure to human peritoneal fluid
Authors: de Haan Bart J. , Rossi Alessandra , Faas Marijke M. , Smelt Maaike J. , Sonvico Fabio , Colombo Paolo , de Vos Paul
Published: May 2011

Microencapsulation of cells is a promising approach to prevent rejection in the absence of immunosuppression. Clinical application, however, is hampered by insufficient insight in factors influencing biocompatibility of the capsules in humans. In the present study we exposed alginate‐based capsules prepared of different types of alginate to human peritoneal fluid. Subsequently we studied the physicochemical changes of the capsule's surface by applying micro‐Fourier Transform Infrared Spectroscopy. We did test alginate‐beads and alginate‐poly‐L‐lysine capsules prepared of different types of alginate. In all tested capsule formulations we found adsorption of components from human peritoneal fluid and clear physicochemical changes of the surface. These changes were alginate‐dependent. The adsorption had no significant effects on the permselective properties of the capsule but we found a strong increase of TNFα production by human peripheral blood mononuclear cells when exposed to alginate‐beads treated with human peritoneal fluid. This elevated responsiveness was not observed with alginate‐PLL capsules. The results show that alginate‐based capsule surfaces always undergo physicochemical changes of the surface when exposed to human peritoneal fluid. This adsorption may lead to enhancement of the inflammatory responses against the microcapsules. Our result implicate that biocompatibility measurements should not only been done with freshly prepared capsules but also with capsules that have been exposed to fluid from the implantation site in order to predict thein vivoresponses. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Inhibition of hydrogen embrittlement of Ni–Ti superelastic alloy in acid fluoride solution by hydrogen peroxide addition
Authors: Yokoyama Ken'ichi , Yazaki Yushin , Sakai Jun'ichi
Published: May 2011

Inhibition of the hydrogen embrittlement of Ni–Ti superelastic alloy in an acidulated phosphate fluoride (APF) solution has been attempted by adding various amounts of H2O2. In a 0.2% APF solution, hydrogen absorption is markedly inhibited by adding H2O2, although corrosion is slightly enhanced by increasing the amount of added H2O2. By adding a small amount of H2O2 (0.001M), in the early stage of immersion, hydrogen embrittlement is inhibited and corrosion is only slightly enhanced. Upon adding H2O2, it appears that the dominant cathodic reactions change from hydrogen evolution to H2O2 reduction reactions, or the surface conditions of the alloy are changed by H2O2 with a high oxidation capability, thereby inhibiting hydrogen absorption. The present study clearly indicates that infinitesimal addition of H2O2 into acid fluoride solutions is effective for the inhibition of the hydrogen embrittlement of the alloy. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Chondrogenic differentiation of neonatal human dermal fibroblasts encapsulated in alginate beads with hydrostatic compression under hypoxic conditions in the presence of bone morphogenetic protein‐2
Authors: Singh Milind , Pierpoint Mallory , Mikos Antonios G. , Kasper F. Kurtis
Published: May 2011

In the present work, neonatal human dermal fibroblasts (nHDFs) were evaluated as a potential cell source for intervertebral disc repair. Chondrogenic differentiation of nHDFs was studied in the presence or absence of hydrostatic compression under normal and hypoxic conditions. In addition, the potentially synergistic effects of mechanical stimulation and bone morphogenetic protein (BMP)‐2 on the chondrogenic differentiation of nHDFs were assessed. Mechanical stimulation was applied to the cells encapsulated in alginate beads using a custom‐built bioreactor system for either a 1‐ or 3‐week period at a frequency of 1 Hz for 4 h/day. In general, after 21 days of culture, high cell viability was observed for all the groups, with the exception of the groups exposed to intermittent mechanical stimulation for 3 weeks. Long‐term intermittent application of mechanical stimulation under low O2 conditions resulted in elevated collagen biosynthesis rate from day 0. Inclusion of BMP‐2 for this group improved the chondrogenic differentiation of nHDFs, as indicated by elevated aggrecan gene expression and an increased collagen production rate compared to the day 0 group. Thus, the combination of hypoxia, BMP‐2 supplementation, and long‐term intermittent application of dynamic hydrostatic pressure was found to be a potent promoter of the chondrogenic differentiation of nHDFs. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Three‐dimensional honeycomb‐patterned chitosan/poly(L‐lactic acid) scaffolds with improved mechanical and cell compatibility
Authors: Zhao Mingyan , Li Lihua , Li Xian , Zhou Changren , Li Bo
Published: May 2011

Micro‐size patterned surfaces trigger specific biological responses such as the promotion of cell growth, cell migration, cell differentiation, and ECM production. The aim of this work was to elaborate three‐dimensional scaffolds with honeycomb patterned surfaces and large open pores, and to study the influence of surface patterning on cell behavior. In this study, we used water droplets as porogen material to prepare a novel type of chitosan sponge with large open pores on its surface. The sponges obtained were then immersed into 6 wt % Poly(L‐lactic acid) chloroform solution to obtain honeycomb patterned composite porous scaffolds. The morphology and mechanical properties were characterized with SEM and compression testing. The fibroblast behaviors in scaffolds were analyzed with SEM, VG, PAS, live‐dead staining, and flow cytometer. Results showed that these composite scaffolds possessed better mechanical properties and hierarchical porous structure than pure chitosan sponges. Cell culture revealed that the honeycomb patterned surface had positive influences on fibroblast behaviors, wherein the cell adhesion, proliferation, ECM secretion and viability were improved dramatically. Such a hierarchical composite scaffold would be a suitable candidate for tissue engineering purposes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Antioxidant role of coumarin on streptozotocin–nicotinamide‐induced type 2 diabetic rats
Authors: Rajarajeswari Narayanasamy , Pari Leelavinothan
Published: May 2011

The purpose of this study was to investigate the antioxidant role of coumarin on streptozotocin–nicotinamide‐induced Type 2 diabetic rats. In experimental rats, the levels of plasma glucose, insulin, and the levels of thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes, and the activities of superoxide dismutase, catalase, glutathione‐S‐transferase, and glutathione peroxidase were assayed in liver and kidney. Diabetic rats showed elevated levels of plasma glucose and lipid peroxidation markers and reduced plasma insulin and antioxidant enzymes. Oral administration of coumarin resulted in a significant reduction in the plasma glucose and lipid peroxides and a significant increase in the plasma insulin and antioxidant enzymes. Chronic treatment of coumarin remarkably restored the normal status of the histopathological changes observed in the selected tissues. It can be concluded that coumarin has antioxidant effect in Type 2 diabetic rats. © 2011 Wiley Periodicals, Inc. J Biochem Mol Toxicol 25:355–361 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20395
PROCOS: Computational analysis of protein–protein complexes
Authors: Fink Florian , Hochrein Jochen , Wolowski Vincent , Merkl Rainer , Gronwald Wolfram
Published: May 2011

One of the main challenges in protein–protein docking is a meaningful evaluation of the many putative solutions. Here we present a program (PROCOS) that calculates a probability‐like measure to be native for a given complex. In contrast to scores often used for analyzing complex structures, the calculated probabilities offer the advantage of providing a fixed range of expected values. This will allow, in principle, the comparison of models corresponding to different targets that were solved with the same algorithm. Judgments are based on distributions of properties derived from a large database of native and false complexes. For complex analysis PROCOS uses these property distributions of native and false complexes together with a support vector machine (SVM). PROCOS was compared to the established scoring schemes of ZRANK and DFIRE. Employing a set of experimentally solved native complexes, high probability values above 50% were obtained for 90% of these structures. Next, the performance of PROCOS was tested on the 40 binary targets of the Dockground decoy set, on 14 targets of the RosettaDock decoy set and on 9 targets that participated in the CAPRI scoring evaluation. Again the advantage of using a probability‐based scoring system becomes apparent and a reasonable number of near native complexes was found within the top ranked complexes. In conclusion, a novel fully automated method is presented that allows the reliable evaluation of protein–protein complexes. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Gastric teeth of some thoracotreme crabs and their contribution to the brachyuran phylogeny
Authors: Brösing Andreas , Türkay Michael
Published: May 2011

The gastric teeth of three ocypodoid species were investigated using scanning electron microscopy, and the morphological results were discussed with respect to the known food preferences. The species were chosen in particular because of contrasting ideas about their relationships within the Thoracotremata. For the genera Heloecius, Dotilla, Mictyris, and “Uca” (s. str.), we find a specific correlation of the gastric teeth with the suspension feeding. The lateral gastric teeth of Uca have no prominent lateral teeth cusps, and most of their teeth surface consists of transverse comb‐like lamellae. However, this possible food adaptation does not exclude the usability of specific teeth characters to distinguish species of suspension feeders. The closer relationship of the Dotillidae to grapsoid lines of gecarcinid or sesarmid crabs suggested by molecular data is not supported by the gastric teeth. For the genus Ucides, we found several characters that distinguish Ucides from the remaining ocypodoid genera Heloecius, Dotilla, Mictyris, and “Uca.” In particular, the structures of the lateral and the dorsomedian teeth show some similarities to genera of the Gecarcinidae and Sesarmidae. Our results suggest that foregut characters can be used for phylogenetic analyses. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Fine structure of the gnathosoma ofArchegozetes longisetusAoki (Acari: Oribatida, Trhypochthoniidae)
Authors: Alberti Gerd , Heethoff Michael , Norton Roy A. , Schmelzle Sebastian , Seniczak Anna , Seniczak Stanisław
Published: May 2011

Oribatida are one of the main groups of Acari comprising mostly important decomposers in soils. Most species are particle feeders, an exceptional mode of nutrition in Arachnida. Hence, their feeding organs, the gnathosoma, are of special functional interest. We studied nearly all components using scanning and transmission electron microscopies as well as reconstructions based on synchrotron X‐ray microtomography from the model oribatidArchegozetes longisetosus. Besides cuticular structures, we describe the full set of muscles and confirm the presence of a trochanter remnant at the base of the chelicera. Setae on the prodorsum and the anterior and posterior infracapitular setae are mechanoreceptors innervated by two dendrites ending with tubular bodies. Dendrites of adoral setae, anterior setae of the chelicerae, and the supracoxal setae show neither obvious tubular bodies nor wall or terminal pores. Thus their function remains obscure. For the first time, a muscular proprioreceptor has been found in Arachnida. It likely monitors the actions of muscles moving the movable digit of the chelicera. Glandular structures within and associated with the gnathosoma are described. Dermal glands represented by secretory porose areas are found within the infracapitulum. More complex associated glands comprise the podocephalic glands and the infracapitular glands, the ducts of which were traced completely for the first time. The components described are mostly fundamental for the gnathosoma of Actinotrichida (Acariformes), one of the two lineages of Acari, to which Oribatida belong. The gnathosoma is generally considered the most relevant putative synapomorphy of Acari. Since the monophyly of Acari has become more and more questionable during the last decades, a thorough reinvestigation of this body part is necessary for a comprehensive understanding of acarine and even arachnid phylogeny and evolution. This article provides a starting point of such a re‐evaluation of the gnathosoma. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Functional morphology of the forelimb of living and extinct tree‐kangaroos (Marsupialia: Macropodidae)
Authors: Warburton Natalie M. , Harvey Kathryn J. , Prideaux Gavin J. , O'Shea James E.
Published: May 2011

Tree‐kangaroos are a unique group of arboreal marsupials that evolved from terrestrial ancestors. The recent discovery of well‐preserved specimens of extinct tree‐kangaroo species (genus Bohra) within Pleistocene cave deposits of south‐central Australia provides a unique opportunity to examine adaptive evolution of tree‐kangaroos. Here, we provide the first detailed description of the functional anatomy of the forelimb, a central component of the locomotor complex, in the extant Dendrolagus lumholtzi, and compare its structure and function with representatives of other extant marsupial families. Several features were interpreted as adaptations for coping with a discontinuous, uneven and three‐dimensional arboreal substrate through enhanced muscular strength and dexterity for propulsion, grasping, and gripping with the forelimbs. The forelimb musculoskeletal anatomy of Dendrolagus differed from terrestrial kangaroos in the following principal ways: a stronger emphasis on the development of muscles groups responsible for adduction, grasping, and gripping; the enlargement of muscles that retract the humerus; and modified shape of the scapula and bony articulations of the forelimb bones to allow improved mobility. Many of these attributes are convergent with other arboreal marsupials. Tree‐kangaroos, however, still retain the characteristic bauplan of their terrestrial ancestors, particularly with regard to skeletal morphology, and the muscular anatomy of the forelimb highlights a basic conservatism within the group. In many instances, the skeletal remains of Bohra have similar features to Dendrolagus that suggest adaptations to an arboreal habit. Despite the irony of their retrieval from deposits of the Nullarbor “Treeless” Plain, forelimb morphology clearly shows that the species of Bohra were well adapted to an arboreal habitat. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Morphological variation in head shape of pipefishes and seahorses in relation to snout length and developmental growth
Authors: Leysen Heleen , Roos Gert , Adriaens Dominique
Published: May 2011

The feeding apparatus of Syngnathidae, with its elongate tubular snout and tiny, toothless jaws, is highly specialized for performing fast and powerful pivot feeding. In addition, the prolonged syngnathid parental care probably enables the juveniles to be provided with a feeding apparatus that resembles the one in adults, both in morphology and function. In this study, a landmark‐based geometric morphometric analysis was carried out on the head of syngnathid representatives in order to (1) examine to what degree pipefish shape variation is different from that of seahorses; (2) determine whether the high level of specialization reduces the amount of intraspecific morphological variation found within the family; and (3) elucidate whether or not important shape changes occur in the seahorse head during postrelease ontogeny. We found that (1) there is a significant shape difference between head shape of pipefish and seahorse: the main differences concern snout length and height, position and orientation of the pectoral fin base, and height of the head and opercular bone. We hypothesize that this might be related to different prey capture kinematics (long snout with little head rotation versus short snout with large head rotation) and to different body postures (in line with the head versus vertical with a tilted head) in pipefishes and seahorses; (2) both pipefishes and seahorses showed an inverse relation between relative snout length and intraspecific variation and although pipefishes show a large diversity in relative snout elongation, they are more constrained in terms of head shape; and (3) the head of juvenile Hippocampus reidi specimens still undergoes gradual shape changes after being expelled from the brood pouch. Ontogenetic changes include lowering of the snout and head but also differences in orientation of the preopercular bone and lowering of the snout tip. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.
Tissue engineering‐based cartilage repair with mesenchymal stem cells in a porcine model
Authors: Chang Chih‐Hung , Kuo Tzong‐Fu , Lin Feng‐Huei , Wang Jyh‐Horng , Hsu Yuan‐Ming , Huang Huei‐Ting , Loo Shiao‐Tung , Fang Hsu‐Wei , Liu Hwa‐Chang , Wang Wen‐Chih
Published: May 2011

This in vivo pilot study explored the use of mesenchymal stem cell (MSC) containing tissue engineering constructs in repair of osteochondral defects. Osteochondral defects were created in the medial condyles of both knees of 16 miniature pigs. One joint received a cell/collagen tissue engineering construct with or without pretreatment with transforming growth factor β (TGF‐β) and the other joint from the same pig received no treatment or the gel scaffold only. Six months after surgery, in knees with no treatment, all defects showed contracted craters; in those treated with the gel scaffold alone, six showed a smooth gross surface, one a hypertrophic surface, and one a contracted crater; in those with undifferentiated MSCs, five defects had smooth, fully repaired surfaces or partially repaired surfaces, and one defect poor repair; in those with TGF‐β‐induced differentiated MSCs, seven defects had smooth, fully repaired surfaces or partially repaired surfaces, and three defects showed poor repair. In Pineda score grading, the group with undifferentiated MSC, but not the group with TGF‐β‐induced differentiated MSCs, had significantly lower subchondral, cell morphology, and total scores than the groups with no or gel‐only treatment. The compressive stiffness was larger in cartilage without surgical treatment than the treated area within each group. In conclusion, this preliminary pilot study suggests that using undifferentiated MSCs might be a better approach than using TGF‐β‐induced differentiated MSCs for in vivo tissue engineered treatment of osteochondral defects. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1874–1880, 2011
Characterization of a cartilage‐like engineered biomass using a self‐aggregating suspension culture model: Molecular composition using FT‐IRIS
Authors: Kim Minwook , Kraft Jeffrey J. , Volk Andrew C. , Pugarelli Joan , Pleshko Nancy , Dodge George R.
Published: May 2011

Maintenance of chondrocyte phenotype and robust expression and organization of macromolecular components with suitable cartilaginous properties is an ultimate goal in cartilage tissue engineering. We used a self‐aggregating suspension culture (SASC) method to produce an engineered cartilage, “cartilage tissue analog” (CTA). With an objective of understanding the stability of phenotype of the CTA over long periods, we cultured chondrocytes up to 4 years and analyzed the matrix. Both early (eCTAs) (6 months) and aged (aCTAs) (4 years) showed type II collagen throughout with higher concentrations near the edge. Using Fourier transform‐infrared imaging spectroscopy (FT‐IRIS), proteoglycan/collagen ratio of eCTA was 2.8 times greater than native cartilage at 1 week, but the ratio was balanced to native level (p = 0.017) by 36 weeks. Surprisingly, aCTAs maintained the hyaline characteristics, but there was evidence of calcification within the tissue with a distinct range of intensities. Mineral/matrix ratio of those aCTA with “intensive” calcification was significantly higher (p = 0.017) than the “partial,” but when compared to native bone the ratio of “intensive” aCTAs was 2.4 times lower. In this study we utilized the imaging approach of FT‐IRIS and have shown that a biomaterial formed is compositionally closely related to natural cartilage for long periods in culture. We show that this culture platform can maintain a CTA for extended periods of time (4 years) and under those conditions signs of mineralization can be found. This method of cartilage tissue engineering is a promising method to generate cartilaginous biomaterial and may have potential to be utilized in both cartilage and boney repairs. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1881–1887, 2011
In vivo strain analysis of the intact supraspinatus tendon by ultrasound speckles tracking imaging
Authors: Kim Yang‐Soo , Kim Jung‐Man , Bigliani Louis U , Kim Hye‐Jin , Jung Hyun‐Woo
Published: May 2011

Limited data exist regarding why delaminated tears occur within the rotator cuff tendon, and no general agreement exists on how to handle this complicated tear. To analyze in vivo intratendinous strain of the supraspinatus tendon, the superficial, middle, and deep regions were marked with speckles using 2D speckle tracking echocardiography (2D STE) of 15 shoulders. The displacement and the strain of each speckle during isotonic and isometric shoulder motion were evaluated. Significantly different displacement and strains in the tendon were found between isometric and isotonic shoulder motions. In isometric motion, the average longitudinal displacement of the speckle at the superficial region (1.66 mm) was larger than at the deep region (0.61 mm), and the average peak strain at the superficial region (17.03%) was also higher than that at the deep region (3.42%). Conversely, in isotonic motion, the average longitudinal displacement of the speckle at the superficial region (0.70 mm) was less than that at the deep region (1.61 mm), and the average peak strain at the superficial region (4.73%) was also lower than that at the deep region (15.69%). A different strain was found between the superficial and deep regions within the intact live supraspinatus tendon. The strain and displacement patterns vary according to isometric versus isotonic shoulder motions. On the basis of our observations, we suggest that the delaminated tear of the rotator cuff tendon must be repaired separately layer by layer to resist the inhomogeneous strain after the repair. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1931–1937, 2011
Long‐term evaluation of a compliant cushion form acetabular bearing for hip joint replacement: A 20 million cycles wear simulation
Authors: Elsner Jonathan J. , Shemesh Maoz , Mezape Yoav , Levenshtein Mario , Hakshur Keren , Shterling Avi , Linder‐Ganz Eran , Eliaz Noam
Published: May 2011

Soft bearing materials that aim to reproduce the tribological function of the natural joint are gaining popularity as an alternative concept to conventional hard bearing materials in the hip and knee. However, it has not been proven so far that an elastic cushion bearing can be sufficiently durable as a long term (∼20 years) articulating joint prosthesis. The use of new bearing materials should be supported by accurate descriptions of the implant following usage and of the number, volume, and type of wear particles generated. We report on a long‐term 20 million cycle (Mc) wear study of a commercial hip replacement system composed of a compliant polycarbonate‐urethane (PCU) acetabular liner coupled to a cobalt–chromium alloy femoral head. The PCU liner showed excellent wear characteristics in terms of its low and steady volumetric wear rate (5.8–7.7 mm3/Mc) and low particle generation rate (2–3 × 106particles/Mc). The latter is 5–6 orders of magnitude lower than that of highly cross‐linked polyethylene and 6–8 orders of magnitude lower than that of metal‐on‐metal bearings. Microscopic analysis of the implants after the simulation demonstrated a low damage level to the implants' articulating surfaces. Thus, the compliant PCU bearing may provide a substantial advantage over traditional bearing materials. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1859–1866, 2011
PEATLAND CONVERSION AND DEGRADATION PROCESSES IN INSULAR SOUTHEAST ASIA: A CASE STUDY IN JAMBI, INDONESIA
Authors: Miettinen J. , Wang J. , Hooijer A. , Liew S.
Published: May 2011

The ongoing conversion and degradation of insular Southeast Asian peat swamp forests causes globally important carbon emissions and leads to loss of unique biodiversity. Little quantitative information is available on the dynamics of peat swamp forest conversion. In this case study, we present a time‐series of peatland conversion and degradation in the Air Hitam Laut peatlands in Jambi Province (Sumatra, Indonesia), which included the Berbak National Park. High‐resolution (10–60 m) satellite imagery was used to map land cover and degradation status for nine time slices between the 1970s and 2009. Nearly‐pristine forest cover was shown to have declined in the study area from 90 to 43 per cent, inside the Berbak National Park from 95 to 73 per cent and outside the National Park from 86 to 25 per cent. Outside the protected area, 66 per cent of former nearly‐pristine forests turned into degraded forests or unmanaged deforested areas. Large‐scale oil palm plantations accounted for 21 per cent of the formerly nearly‐pristine areas and small‐holder agriculture for 8 per cent. The conversion to plantation has fast accelerated since 2002. Conversion from nearly‐pristine forest to plantation typically took around 6 years, at times up to 10 years. Better understanding of conversion and degradation dynamics will allow for improved estimates of the implications of management planning decisions taken in peatland areas. Copyright © 2011 John Wiley & Sons, Ltd.
Some Random sequences related to average density of self‐similar measures
Authors: Xiong Ying , Wen Zhi‐Xiong
Published: May 2011

In this paper we study the limit behavior of weighted averages of some random sequence related to Bernoulli random variables, and apply the results to average density of self‐similar measures. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
On neighborhoods of analytic functions with positive real part
Authors: Sokó Janusz
Published: May 2011

Let h(z) = z + a2z2 + ⋅⋅⋅ be analytic in the unit disc \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\cal U}$\end{document} on the complex plane \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathbf {C}$\end{document}. For given κ < 1, \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\zeta \in \mathbf {C}$\end{document}, ℜζ > κ, we prove that if ζh′(z) ∈ Ω(κ, ζ) for all \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$z\in {\cal U}$\end{document}, then ℜ[ζh(z)/z] > κ for all \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$z\in {\cal U}$\end{document}, where \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Omega (\kappa ,\zeta )=\lbrace w\in {\mathbf {C}}:|w-2\kappa +\overline{\zeta }|>|\Re w -\kappa |\rbrace$\end{document} is a concave domain with boundary being a parabola. Next we consider the classes of analytic functions \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${{\cal P}(\alpha )}=\lbrace p:p(0)=1,\Re [p(z)\alpha \rbrace$\end{document} and \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\cal {P^{\prime }}}(\alpha )=\left\lbrace p:p(0)=1,\ [zp(z)]^{\prime }\in \Omega (\alpha ,1)\right\rbrace$\end{document}. For \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$q\in \cal {P^{\prime }}(\alpha )$\end{document} we find a sufficient condition on δ that implies the existence of a δ ‐neighborhood \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\widehat{N}_\delta (q)$\end{document} being contained in \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\cal P}(\beta )$\end{document}, where β ⩽ α < 1. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Lower extremity free flap reconstruction outcomes using venous coupler
Authors: Ducic Ivica , Brown Benjamin J. , Rao Samir S.
Published: May 2011

Background: Microvascular anastomotic coupling devices have been available to microsurgeons for over 20 years. Many studies have validated the efficacy of these devices for venous anastomosis. To date, there have been no large reports of their success in the anatomical region with the highest free flap failure rate, the lower extremity. Methods: A retrospective review of 67 consecutive patients who underwent lower extremity microvascular reconstruction performed from August 2003 to September 2010 was performed. Patient charts were reviewed for age, sex, medical comorbidities, etiology of defect, location of defect, flap type, anastomotic technique, complications, flap survival, and limb salvage outcome. Results: No patients returned to the operating room to have an arterial or venous anastomosis revised. Despite 100% vascular anastomosis patency rates in 67 consecutive lower extremity free flaps, flap survival rate was 95.5%. Total complication rate (13.4%) was due to two partial and one complete flap loss, three infections, two skin graft loses, and one hematoma. There were no intraoperative or perioperative complications involving the use of a microvascular anastomotic coupling device itself. Thirty‐day and long term limb salvage rate was 97% and 92.5%, respectively. Conclusion: Microvascular anastomotic coupling devices create effective venous anastomoses in lower extremity microvascular reconstruction. Thus, it presents an important tool in the armamentarium for lower extremity microsurgical reconstruction. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Mesh epineurial splinting for late median nerve repair in older patients: A preliminary report
Authors: Bertelli Jayme Augusto , Kechele Paulo Roberto , Ghizoni Marcos Flávio , Fröde Tânia S.
Published: May 2011

Eleven patients over 40 years old, with median nerve lesions at the wrist, were operated on an average of 5 months after their injury. In six patients, the median nerve was repaired using a polypropylene mesh applied to secure the nerve stumps in contact, thereby allowing for direct repair with microsutures. Six patients had their median nerve repaired with sural grafts. The average gap length was 2.8 cm for the mesh repair, whereas it was 3.7 cm for the graft repair group. Eighteen months after surgery, pressure thresholds were perceived in the index and thumb pulp by all six patients with a mesh repair but in only two of five patients with a graft repair. Five in the mesh repair group recovered function in the abductor pollicis brevis muscle, versus none in the graft group. These preliminary results suggest that, in older patients, the use of a mesh to splint the coaptation site followed by direct nerve repair yields better recovery than conventional sural grafts. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Free tissue transfer in reconstruction following soft tissue sarcoma resection
Authors: Penna Vincenzo , Iblher Niklas , Momeni Arash , Stark G. Björn , Bannasch Holger
Published: May 2011

Background: Radical surgical resection remains the single‐most important treatment in the curative multimodal therapy of soft tissue sarcomas. Refinements in surgical techniques have resulted in the development of function preserving approaches increasingly avoiding limb amputation. Patients and methods: The records of all patients (n = 34) who underwent microsurgical soft tissue coverage subsequent to primary resection of soft tissue sarcoma of the upper or lower limb from 1999 to 2009 are reviewed regarding postoperative complications, time until start of adjuvant radiation and functional outcome (Toronto Extremity Salvage Score, TESS). Results: Thirty‐four patients (range: 21–86 years) received a total of 35 free flaps. Complete tumor resection was obtained in 33 patients, one patient required re‐excision ultimately resulting in tumor‐free margin status (R0 resection). Major complications were encountered in four cases including one patient with complete flap loss requiring an additional free flap and three patients with partial flap loss requiring split‐thickness skin graft procedures. Minor complications were observed in three patients (9%). Extremity salvage could be achieved in 33 patients with adequate postoperative ambulation (TESS 84 ± 18) and adequate use of the upper extremity (TESS 80 ± 22). One patient underwent amputation. Mean time until start of adjuvant radiotherapy was 37 days (range 24–56 days). Conclusion: A synergetic center‐based interdisciplinary approach is crucial in therapeutical management of soft tissue sarcomas with the aim of R0 resection status and limb preservation. Plastic surgery contributes by offering microsurgical reconstruction using free tissue transfer, thus broadening surgical possibilities. This increases the chance of both adequate oncosurgical resection and limb preservation. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Intravenous heparin use in digital replantation and revascularization: The Quebec provincial replantation program experience
Authors: Nikolis Andreas , Tahiri Youssef , St‐Supery Veronique , Harris Patrick G. , Landes Genevieve , Lessard Lucie , Sampalis John
Published: May 2011

Background: No consensus exists among microsurgeons regarding the role of intravenous (IV) heparin in digital replantation/revascularization. The current experience of the Provincial Replantation Center in Quebec was reviewed over a 4‐year period. Methods: An initial retrospective review of all revascularized or reimplanted digits at our Replantation Center from April 2004 to April 2006 was conducted. Then, data of all patients treated at our center from January 08 to September 08 were prospectively collected. The two cohorts were compared with regards to demographics, injury characteristics, postoperative thromboprophylaxis medication as well as complication and success rates. Proportions were compared using χ2 tests/Fisher's exact tests. Multivariate analysis was conducted with logistic regression. Results: 175 digits were treated from April 2004 to April 2006, including 104 revascularizations and 71 amputations. IV heparin was used in 35.1% of the cases and was associated with a 3.59‐fold (95% CI, 1.55–8.31) increase risk of developing a complication compared with cases where heparin was not used (P = 0.001). In 2008, 106 digits were treated. IV heparin was used in 14.6% of the cases and was not significantly associated with a higher complication rate compared with cases where heparin was not used (P = 0.612). Both cohorts' success rates were very similar (P = 0.557). The number of complications decreased from the first period (20.5%) to the second one (12.8%). Conclusion: Routine use of IV heparin following digital replantation and revascularization is not warranted. Surgical technique and type of injury remains the most important predictors for success in these complex procedures. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Changes in arterial blood flow of free flaps after the administration of sildenafil in swine
Authors: Gravvanis Andreas , Papalois Apostolos , Delikonstantinou Iraklis , Pentilas Nicolaos , Zogogiannis Ioannis , Tsoutsos Dimosthenis , Karakitsos Dimitrios
Published: May 2011

We evaluated blood flow changes after experimental free tissue transfer and the potential hemodynamic effect of sildenafil on the free flap. Sixteen swine were used for free transfer of a latissimus dorsi myocutaneous flap to the chest that was anastomosed to the internal mammary vessels, and were randomized into controls and study group. The latter received a single dose of sildenafil, 6 hours following flap revascularization. Doppler ultrasonography revealed that arterial flow was mainly systolic postoperatively. Diastolic flow patterns were gradually restored after the first postoperative day. Pulsatility index (PI) significantly increased and flow volume decreased in all animals postoperatively. In the sildenafil group, PI significantly decreased and flow volume increased, while diastolic flow patterns were restored earlier on compared to controls, postoperatively. In conclusion, the administration of sildenafil after free tissue transfer increases flow volume and facilitates the restoration of diastolic blood flow patterns in the early critical postoperative period. © 2011 Wiley‐Liss, Inc. Microsurgery 2011.
Modeling of Look‐Locker estimates of the magnetic resonance imaging estimate of longitudinal relaxation rate in tissue after contrast administration
Authors: Paudyal Ramesh , Bagher‐Ebadian Hassan , Nagaraja Tavarekere N. , Fenstermacher Joseph D. , Ewing James. R.
Published: May 2011

This paper models the behavior of the longitudinal relaxation rate of the protons of tissue water R1 (R1 = 1/T1), measured in a Look‐Locker experiment at 7 Tesla after administration of a paramagnetic contrast agent (CA). It solves the Bloch‐McConnell equations for the longitudinal magnetization of the protons of water in a three‐site two‐exchange (3S2X) model with boundary conditions appropriate to repeated sampling of magnetization. The extent to which equilibrium intercompartmental water exchange kinetics affect monoexponential estimates of R1 after administration of a CA in dynamic contrast enhanced experiment is described. The relation between R1 and tissue CA concentration was calculated for CA restricted to the intravascular, or to the intravascular and extracellular compartments, by varying model parameters to mimic experimental data acquired in a rat model of cerebral tumor. The model described a nearly linear relationship between R1 and tissue concentration of CA, but demonstrated that the apparent longitudinal relaxivity of CA depends upon tissue type. The practical consequence of this finding is that the extended Patlak plot linearizes the ΔR1 data in tissue with leaky microvessels, accurately determines the influx rate of the CA across these microvessels, but underestimates the volume of intravascular blood water. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Design of a radiative surface coil array element at 7 T: The single‐side adapted dipole antenna
Authors: Raaijmakers A. J. E. , Ipek O. , Klomp D. W. J. , Possanzini C. , Harvey P. R. , Lagendijk J. J. W. , van den Berg C. A. T.
Published: May 2011

Ultra high field MR imaging (≥7 T) of deeply located targets in the body is facing some radiofrequency‐field related challenges: interference patterns, reduced penetration depth, and higher Specific Absorbtion Ratio (SAR) levels. These can be alleviated by redesigning the elements of the transmit or transceive array. This is because at these high excitation field (B1) frequencies, conventional array element designs may have become suboptimal. In this work, an alternative design approach is presented, regarding coil array elements as antennas. Following this approach, the Poynting vector of the element should be oriented towards the imaging target region. The single‐side adapted dipole antenna is a novel design that fulfills this requirement. The performance of this design as a transmit coil array element has been characterized by comparison with three other, more conventional designs using finite difference time domain (FDTD) simulations and B measurements on a phantom. Results show that the B level at the deeper regions is higher while maintaining relatively low SAR levels. Also, the B field distribution is more symmetrical and more uniform, promising better image homogeneity. Eight radiative antennas have been combined into a belt‐like surface array for prostate imaging. T1‐weighted (T1W) and T2‐weighted (T2W) volunteer images are presented along with B measurements to demonstrate the improved efficiency. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Quantitative myocardial perfusion imaging with a MR cold pressor test
Authors: Ritter C.O. , Kowalski M. , Weng A. M. , Beer M. , Hahn D. , Köstler H.
Published: May 2011

The response of myocardial blood flow to sympathetic stimulation with cold is modulated by endothelium‐related factors. As endothelial dysfunction is an early step in patients with coronary artery disease, the aim of this study was to establish a cold pressor test (CPT) setting for quantitative analysis of myocardial perfusion in a MR scanner. First pass perfusion studies were performed in 10 healthy volunteers using a 1.5 T MR scanner with a multislice steady state free precession perfusion trueFISP sequence in prebolus technique (1 cc/4 cc gadobenate dimeglumine). MR‐CPT was established using an over head ice‐water bath of the left hand. First pass perfusion imaging was started after 1 min to assure an adequate stimulus followed by a second series after 15 min to evaluate the rest perfusion. After motion correction images were segmented with an adapted, automated tool, myocardial contours were determined. Perfusion was quantitatively evaluated after contamination and baseline correction by deconvolution with the arterial input function using an exponential function model as residuum. All data could be evaluated. Mean myocardial perfusion rose from 0.61 ± 0.22 cc/g/min at rest to 1.15 ± 0.34 cc/g/min under CPT. MR myocardial perfusion values show a comparable increase under CPT as published positron emission tomography data. Consequently, CPT for the presence of endothelial dysfunction is feasible in the MR environment. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
MRI of frozen tissue demonstrates a phase shift
Authors: Lu Aiming , Daniel Bruce L. , Kaye Elena , Butts Pauly Kim
Published: May 2011

While temperature mapping is desired during cryosurgery for prostate cancer treatment, an effective approach for this purpose is still needed. We have demonstrated a phase shift with temperature in our in vivo canine experiments and ex vivo tissue sample experiments within the frozen tissue. The phase shift is much larger (∼0.7 °/°C with an echo time of 0.1 ms at 0.5 T) in magnitude than that predicted by conventional proton resonant frequency shift (0.008 °/°C). It shows little dependence on the echo times used and thus is not due to a frequency change, although frequency‐dependent phase shift has been observed near the frozen tissue. This phase shift varies monotonically with temperature within the frozen tissue and therefore may be potentially used as a novel temperature mapping approach in cryoablation applications. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.