bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biocompatibility and osseointegration of β‐TCP: Histomorphological and biomechanical studies in a weight‐bearing sheep model
Authors: Koepp Holger E. , Schorlemmer Sandra , Kessler Stefan , Brenner Rolf E. , Claes Lutz , Günther Klaus‐Peter , Ignatius Anita A. 
Published: May 2004

AbstractThe aim of the study was to investigate the biocompatibility, degradation, and biomechanical properties of β‐TCP (Cerasorb®) in a weight‐bearing sheep model. β‐TCP implant prototypes were implanted in the tibial head of adult merino sheep. After 6 and 12 months material explants were harvested for biomechanical, histological, and histomorphometrical analysis. Corresponding bone specimens of the intact bone of the contralateral leg were used as controls in the biomechanical test. Compression tests showed higher values for maximum fracture load, yield strength, and compression modulus after 6 and 12 months compared to control. Microscopically, the implants showed good osteoconduction and were incorporated into the bone; however, relevant amounts of β‐TCP were still present after 12 months. Histomorphological results revealed that β‐TCP had partially degraded between implantation and 6 months, but its share remained constant between 6 and 12 months. The bone volume fraction in the area of the implant (46% ± 6.5%) was initially higher than in the corresponding bone area of the contralateral leg (31% ± 9.6%), but after 12 months declined to 29% ± 9.4% (control: 33% ± 8.3%), while the share of β‐TCP remained constant at 36% ± 12.2%. These findings were supported by microradiographic data. In conclusion, in a weight bearing implantation model β‐TCP showed good biocompatibility, osseointegration and beginning degradation, even though it was not further degraded between 6 and 12 months. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 209–217, 2004
Bioresorbable nanofiber‐based systems for wound healing and drug delivery: Optimization of fabrication parameters
Authors: Katti Dhirendra S. , Robinson Kyle W. , Ko Frank K. , Laurencin Cato T. 
Published: May 2004

AbstractWound healing is a complex process that often requires treatment with antibiotics. This article reports the initial development of a biodegradable polymeric nanofiber‐based antibiotic delivery system. The functions of such a system would be (a) to serve as a biodegradable gauze, and (b) to serve as an antibiotic delivery system. The polymer used in this study was poly(lactide‐co‐glycolide) (PLAGA), and nanofibers of PLAGA were fabricated with the use of the electrospinning process. The objective of this study was to determine the effect of fabrication parameters: orifice diameter (needle gauge), polymer solution concentration, and voltage per unit length, on the morphology and diameter of electrospun nanofibers. The needle gauges studied were 16 (1.19 mm), 18 (0.84 mm), and 20 (0.58 mm), and the range of polymer solution concentration studied was from 0.10 g/mL to 0.30 g/mL. The effect of voltage was determined by varying the voltage per unit electrospinning distance, and the range studied was from 0.375 kV/cm to 1.5 kV/cm. In addition, the mass per unit area of the electrospun nanofibers as a function of time was determined and the feasibility of antibiotic (cefazolin) loading into the nanofibers was also studied. The results indicate that the diameter of nanofibers decreased with an increase in needle gauge (decrease in orifice diameter), and increased with an increase in the concentration of the polymer solution. The voltage study demonstrated that the average diameter of the nanofibers decreased with an increase in voltage. However, the effect of voltage on fiber diameter was less pronounced as compared to polymer solution concentration. The results of the areal density study indicated that the mass per unit area of the electrospun nanofibers increased linearly with time. Feasibility of drug incorporation into the nanofibers was demonstrated with the use of cefazolin, a broad‐spectrum antibiotic. Overall, these studies demonstrated that PLAGA nanofibers can be tailored to desired diameters through modifications in processing parameters, and that antibiotics such as cefazolin can be incorporated into these nanofibers. Therefore, PLAGA nanofibers show potential as antibiotic delivery systems for the treatment of wounds. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 286–296, 2004
Improved collagen bilayer dressing for the controlled release of drugs
Authors: Sripriya Ramasamy , Kumar Muthusamy Senthil , Sehgal Praveen Kumar 
Published: May 2004

AbstractA novel bilayer dressing has been developed from bovine succinylated collagen. The dressing contains an antibiotic, Ciprofloxacin, for both immediate and time‐regulated release for controlling the infection, as the infected open wounds need special care. The dressing consists of a sponge and a film, both prepared from succinylated bovine collagen. The sponge has a smooth surface on one side; its rough surface on the other side forms the bilayer system with the film. Both sponge and film act as an anionic reservoir to hold the cationic Ciprofloxacin. The drug, after dispersing in poly (N‐vinyl‐2‐pyrrolidione) (PVP) solution is allowed to spread in the bilayer system by diffusion. The drug stays in the bilayer system because of ionic binding, but starts releasing when comes in contact with the wound. Release of the drug is immediate, but it is regulated by ionic binding between the drug and succinylated collagen. The wound exudates, and there is a polarity‐controlled release of the drug from the bilayer system. The PVP and bilayer system permits only time‐regulated release, and the system lasts up to 5 days with therapeutically sufficient drug availability. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 389–396, 2004
The behavior of novel hydrophilic composite bone cements in simulated body fluids
Authors: Boesel Luciano F. , Fernandes Maria H. V. , Reis Rui L. 
Published: May 2004

AbstractComposite bone cements were formulated with bioactive glass (MgOSiO23CaO · P2O5) as the filler and hydrophilic matrix. The matrix was composed of a starch/cellulose acetate blend (SCA) as the solid component and a mixture of methylmethacrylate/acrylic acid (MMA/AA) as the liquid component. The curing parameters, mechanical properties, and bioactive behavior of these composite cements were determined. The addition of up to 30 wt % of glass improved both compressive modulus and yield strength and kept the maximum curing temperature at the same value presented by a typical acrylic‐based commercial formulation. The lack of a strongly bonded interface (because no coupling agent was used) had important effects on the swelling and mechanical properties of the novel bone cements. However, bone cements containing AA did not show a bioactive behavior, because of the deleterious effect of this monomer on the calcium phosphate precipitation on the polymeric surfaces. Formulations without AA were prepared with MMA or 2‐hydroxyethyl methacrylate (HEMA) as the liquid component. Only these formulations could form an apatite‐like layer on their surface. These systems, therefore, are very promising: They are bioactive, hydrophilic, partially degradable, and present interesting mechanical properties. This combination of properties could facilitate the release of bioactive agents from the cement, allow bone ingrowth in the cement, and induce a press‐fitting effect, improving the interfaces with both the prosthesis and the bone. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 368–377, 2004
Porous alginate/hydroxyapatite composite scaffolds for bone tissue engineering: Preparation, characterization, and in vitro studies
Authors: Lin Hong‐Ru , Yeh Yu‐Jen 
Published: May 2004

AbstractIn this study a series of alginate/hydroxyapatite (HAP) composite scaffolds was prepared by phase separation. HAP was incorporated into the alginate gel solution to improve both the mechanical and cell‐attachment properties of the scaffolds. These scaffolds had a well‐interconnected porous structure with an average pore size of 150 μm and over 82% porosity. The alginate/HAP scaffold prepared at −40°C with a 50% HAP content showed the best mechanical properties. The morphology of scaffolds could be manipulated by tuning the quenching temperature during the preparation. The dissolution of alginate/HAP composite scaffolds could be slowed by the pretreating them by immersion in 1.0M CaCl2 solution. The rat osteosarcoma UMR106 cells, an osteoblastic cell line, seeded in the scaffolds, displayed better cell attachment to the 75/25 and 50/50 alginate/HAP composite scaffolds than to the pure alginate scaffold. The natural polymeric sponges that fabricated in this study may be a promising approach for tissue‐engineering applications. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 52–65, 2004
Development of the force field parameters for phosphoimidazole and phosphohistidine
Authors: Kosinsky Yuri A. , Volynsky Pavel E. , Lagant Philippe , Vergoten Gerard , Suzuki Ei‐Ichiro , Arseniev Alexander S. , Efremov Roman G. 
Published: May 2004

AbstractPhosphorylation of histidine‐containing proteins is a key step in the mechanism of many phosphate transfer enzymes (kinases, phosphatases) and is the first stage in a wide variety of signal transduction cascades in bacteria, yeast, higher plants, and mammals. Studies of structural and dynamical aspects of such enzymes in the phosphorylated intermediate states are important for understanding the intimate molecular mechanisms of their functioning. Such information may be obtained via molecular dynamics and/or docking simulations, but in this case appropriate force field parameters for phosphohistidine should be explicitly defined. In the present article we describe development of the GROMOS96 force field parameters for phosphoimidazole molecule—a realistic model of the phosphohistidine side chain. The parameterization is based on the results of ab initio quantum chemical calculations with subsequent refinement and testing using molecular mechanics and molecular dynamics simulations. The set of force constants and equilibrium geometry is employed to derive force field for the phosphohistidine moiety. Resulting parameters and topology are incorporated into the molecular modeling package GROMACS and used in molecular dynamics simulations of a phosphohistidine‐containing protein in explicit solvent. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1313–1321, 2004
Cytokine‐induced cell death in human oligodendroglial cell lines. II: Alterations in gene expression induced by interferon‐γ and tumor necrosis factor‐α
Authors: Buntinx Mieke , Gielen Ellen , Van Hummelen Paul , Raus Jef , Ameloot Marcel , Steels Paul , Stinissen Piet 
Published: May 2004

AbstractCytokines, such as interferon‐γ (IFN‐γ) and tumor necrosis factor‐α (TNF‐α), can initiate dual effects resulting in either cell growth or cell death. In this study, the human oligodendroglial cell lines HOG and MO3.13 were used as a model to study the molecular mechanisms of cytokine‐induced cell death in human oligodendrocytes. We have previously shown that TNF‐α and IFN‐γ induce apoptosis in both oligodendroglial cell lines within 72 hr. In the present study, the cell death pathways operating within these cells were further investigated at the gene expression level. Both cell lines express a broad repertoire of caspases and apoptosis‐related genes. Some of these genes are specifically up‐regulated by cytokine treatment; e.g., caspase‐1 is up‐regulated by IFN‐γ. In addition to direct cytotoxic effects, IFN‐γ and TNF‐α also enhance the expression of Fas, TNFR1, and MHC class I molecules in both cell lines. This suggests that cytokines can make oligodendrocytes more vulnerable to different cell death pathways in an inflammatory environment. cDNA microarray analysis of the HOG cell line revealed that TNF‐α induces genes that regulate apoptosis, survival, inflammation, cell metabolism, and cell signaling. The data suggest that oligodendroglial cells activate both death and survival pathways upon cytokine challenges. However, the survival pathways seem to be unable to compete with the death signal after more than 24 hr of cytokine treatment. These results may contribute to the development of therapeutic strategies aimed at interfering with cytokine‐induced cell death of oligodendrocytes in patients with multiple sclerosis. © 2004 Wiley‐Liss, Inc.
Alpha‐dystroglycan interactions affect cerebellar granule neuron migration
Authors: Qu Qiang , Smith Frances I. 
Published: May 2004

AbstractThe interaction of alpha‐dystroglycan (a‐DG) with its extracellular binding partners requires glycans attached to its mucin core domain, and defects in the glycosylation of a‐DG are associated with both muscular dystrophy and neuronal migration defects. The involvement of a‐DG and one of its ligands, agrin, in cerebellar neuronal migration was investigated. Antibodies directed against glycosylated a‐DG inhibited granule neuron migration in cerebellar slice cultures. a‐DG interactions did not appear to influence neurite outgrowth in cerebellar explant cultures, but enhanced granule neuron binding was observed on cells transfected with a‐DG. These results suggest that interactions involving a‐DG influence the strength of attachment of granule neurons to the a‐DG‐expressing Bergmann glial cells that guide granule neuron migration in the cerebellum. Experiments using anti‐agrin antibodies suggest that agrin is not involved in these interactions. © 2004 Wiley‐Liss, Inc.
Activation and Polymerisation of ansa‐Zirconocene Chloroamido Complexes
Authors: Seraidaris Tanja , Löfgren Barbro , Mäkelä‐Vaarne Nora , Lehmus Petri , Stehling Udo 
Published: May 2004

AbstractSummary: Propene polymerisation was conducted with three ansa‐zirconocene complexed: Me2Si(2‐Me‐4‐PhInd)2ZrCl2 (A), Me2Si(2‐Me‐4‐PhInd)2ZrClNMe2 (B) and Me2Si(2‐Me‐4‐PhInd)2ZrClNEt2 (C). Methylalumoxane (MAO) or [HNPhMe2][B(C6F5)4] was used as cocatalyst. The influence of cocatalysts and triisobutylaluminum (TIBA) on polymerisation activity, molecular weight and polymer microstructure was studied. Furthermore, the alkylation and activation of the complexes were examined using UV/VIS spectroscopy. Complex A was the most active in polymerisation, but polymers produced by B and C had in general higher molecular weights. Replacing MAO partially by TIBA increased the molecular weight and prevented catalyst deactivation. According to the UV/VIS measurements, all complexes have low reactivity towards TMA and TIBA. Similar cationic species were formed of all three studied zirconocenes in the reaction with MAO. Additional TIBA did not affect the type of active species formed in the reaction of zirconocene and MAO, but increased the activity of B and C.UV/VIS spectrum of complex A with MAO and with a MAO/TIBA mixture.imageUV/VIS spectrum of complex A with MAO and with a MAO/TIBA mixture.
Role of ulnar forearm free flap in oromandibular reconstruction
Authors: Gabr E.M. , Kobayashi M.R. , Salibian A.H. , Armstrong W.B. , Sundine M. , Calvert J.W. , Evans G.R.D. 
Published: May 2004

AbstractThe ulnar forearm flap is not frequently utilized for oromandibular reconstruction. This study evaluated the usefulness of the ulnar free flap for reconstruction. A retrospective study of 32 patients was conducted. The ulnar forearm flap was combined with an osseous flap in 24 patients. Nine females and 23 males with a mean age of 58.15 years comprised our study population. Squamous‐cell carcinoma was the diagnosis in 93.75% of cases (56.25% T4), of which 20% were recurrent. Functional evaluation of swallowing was based on the University of Washington Questionnaire (UWQ). The mean hospital stay was 9.8 days. The external carotid (100%) was the recipient artery, and the internal jugular (74.07%) was the main recipient vein. Overall flap survival was 96.8%. One flap was lost due to unsalvageable venous thrombosis. Major local complications were seen in 9.4% of cases and included partial flap loss, hematoma, and an orocutaneous fistula. At the time of this study, 21 patients were available for functional evaluation. Speech was rated excellent and good in 33.3% of patients. Swallowing was found good in 28.6% of patients. Chewing was rated excellent and good in 47.6% of patients. Cosmetic acceptance was rated good in 71.4% of cases. The ulnar forearm is a useful free flap in oromandibular reconstruction. It is available when the radial artery is the dominant artery of the hand. Being more hidden, it may be more cosmetically accepted. It affords pliable soft tissue for lining and/or covering of oromandibular defects, and can be used as a second choice after other free‐flap failures. © 2004 Wiley‐Liss, Inc.
On the solution of an initial‐boundary value problem that combines Neumann and integral condition for the wave equation
Authors: Dehghan Mehdi 
Published: May 2004

AbstractNumerical solution of hyperbolic partial differential equation with an integral condition continues to be a major research area with widespread applications in modern physics and technology. Many physical phenomena are modeled by nonclassical hyperbolic boundary value problems with nonlocal boundary conditions. In place of the classical specification of boundary data, we impose a nonlocal boundary condition. Partial differential equations with nonlocal boundary specifications have received much attention in last 20 years. However, most of the articles were directed to the second‐order parabolic equation, particularly to heat conduction equation. We will deal here with new type of nonlocal boundary value problem that is the solution of hyperbolic partial differential equations with nonlocal boundary specifications. These nonlocal conditions arise mainly when the data on the boundary can not be measured directly. Several finite difference methods have been proposed for the numerical solution of this one‐dimensional nonclassic boundary value problem. These computational techniques are compared using the largest error terms in the resulting modified equivalent partial differential equation. Numerical results supporting theoretical expectations are given. Restrictions on using higher order computational techniques for the studied problem are discussed. Suitable references on various physical applications and the theoretical aspects of solutions are introduced at the end of this article. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Discrete compactness property for quadrilateral finite element spaces
Authors: Gardini Francesca 
Published: May 2004

AbstractThe main purpose of the present article is to prove the discrete compactness property for Arnold‐Boffi‐Falk spaces of any order. Results of numerical experiments confirming the theory are also reported. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
4S neuroblastoma: The long‐term outcome
Authors: Levitt G.A. , Platt K.A. , De Byrne R. , Sebire N. , Owens C.M. 
Published: May 2004

AbstractBackgroundStage 4S neuroblastoma is associated with a high rate of spontaneous maturation and involution, with survival rates of 70–90%. There is little long‐term follow‐up data describing the disease status or late effects. The aim of this study was to assess the clinical outcome and imaging findings in long‐term survivors of 4S neuroblastoma.MethodsThe patient population was identified from a single centre over 26 years. Twenty‐five of 31 consecutive patients were long‐term survivors. Five died from disease progression and one from cerebral palsy related complications. All survivors underwent clinical examination. Abdominal ultrasound scanning, liver function tests, hepatitis viral screen, and urinary catecholamines were performed.ResultsThe mean age at diagnosis was 8 ± 9 weeks with a mean age when studied of 11 years and 10 months ± 8 years. Twenty of 25 had no significant clinical findings, three had disease associated clinical abnormalities (neurological, multiple subcutaneous nodules). Three patients had treatment related effects (small testes, urethral stricture, radiation induced soft tissue hypoplasia, post‐surgical Horners syndrome). Persistant adrenal enlargement and calcification was noted in three patients. Twelve patients had abnormal liver ultrasound findings ranging from mildly coarse echotexture to structural changes without evidence of hepatic dysfunction or infection. Treatment did not correlate with abnormal hepatic ultrasound findings.ConclusionsThe majority of long‐term survivors of stage 4S neuroblastoma have no clinically or radiologically significant sequelae but do have residual abnormalities. These findings have implications for subsequent management of unrelated medical conditions in this patient group. © 2004 Wiley‐Liss, Inc.
A survey of clinical productivity and current procedural terminology (CPT) coding patterns of pediatric hematologist/oncologists
Authors: Griffin Timothy C. , Hutter John J. , Johnson Kimberly K. , Moscow Jeffrey A. 
Published: May 2004

AbstractBackgroundSubspecialty‐specific normative values for clinical productivity of practicing pediatric hematologist/oncologists have not been well established. This information could be a useful adjunct in administrative decision‐making in areas such as necessary levels of physician staffing and development of compensation plans.MethodsCurrent procedural terminology (CPT) coding information was obtained from 27 pediatric hematology/oncology groups. Clinical productivity was assessed by overall number of patient encounters and the total number of physician work relative value units (RVU) as defined by the resource‐based relative value scale. The average physician productivity within each individual program was calculated. To determine uniformity of CPT coding, an additional survey solicited mock patient encounter documentation and CPT coding for a simple clinical vignette.ResultsA broad range of clinical productivity was observed for both numbers of patient encounters and RVU. Evaluation of the CPT coding data of the surveyed groups revealed differences in usage of certain evaluation and management (E/M) codes and procedural and specimen interpretation codes. Within individual categories of E/M service codes, a wide variation in assigned CPT code levels was also observed. This observation was supported by differences in the E/M coding for the clinical vignette.ConclusionsAssessment and tracking of physician productivity can provide useful information for the administrative management of pediatric hematology/oncology programs. Caution must be exercised, however, when making productivity comparisons with other subspecialties or even between pediatric hematology/oncology programs. Such comparisons should take into account the number of patient encounters, characteristics of E/M coding patterns, the use of physician extenders, as well as overall RVU production. © 2004 Wiley‐Liss, Inc.