bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of endoscopic resection followed by radiotherapy for primarily diagnosed adenocarcinomas of the paranasal sinuses
Authors: Bogaerts Sofie , Vander Poorten Vincent , Nuyts Sandra , Van den Bogaert Walter , Jorissen Mark
Published: February 2008

Background

Adenocarcinoma is the most frequent histological subtype of paranasal sinus malignancy diagnosed in Belgium. Classical treatment consists of an external surgical approach (lateral rhinotomy with medial maxillectomy or craniofacial resection) followed by radiotherapy. The role, possibilities, and limitations of endoscopic sinus surgery (ESS) are to date unknown.

Methods

We studied 44 patients with primary (not treated previously) adenocarcinoma treated with endoscopic sinus surgery and radiotherapy between 1992 and 2004.

Results

The median follow‐up of the patients alive at the end of the study period was 36 months. For the 3‐year follow‐up, the overall survival, disease‐specific survival, and local control rate were 81%, 91%, and 73%, respectively. Corresponding rates for the 5‐year follow‐up were 53%, 83%, and 62%. Union Internationale Contre le Cancer T classification did not appear to influence these results.

Conclusions

Endoscopic sinus surgery followed by radiotherapy for primary adenocarcinoma of the paranasal sinuses gives oncological results comparable to those of standard external approaches. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Lateral oromandibular defect: When is it appropriate to use a bridging reconstruction plate combined with a soft tissue revascularized flap?
Authors: Chepeha Douglas B. , Teknos Theodoros N. , Fung Kevin , Shargorodsky Josef , Sacco Assuntina G. , Nussenbaum Brian , Jones Lamont , Eisbruch Avraham , Bradford Carol R. , Prince Mark E. , Moyer Jeffrey S. , Lee Julia S. , Wolf Gregory T.
Published: February 2008

Background

A quasi‐experimental retrospective study was undertaken to evaluate a new concept of free tissue volume restoration combined with bridging reconstruction plate (compartment approach) to reduce plate‐related complication rates.

Methods

We evaluated 40 patients with large lateral mandible defects and associated complex soft tissue defects reconstructed with a revascularized soft tissue flap and titanium hollow screw reconstruction plates. A case‐control comparison was performed based on reconstruction type: restoration of soft tissue defect (conventional approach—group 1) versus over‐reconstruction of soft tissue defect (compartment approach—group 2).

Results

Plate exposure rate was 6 of 16 (38%) in group 1 versus 2 of 24 (8%) in group 2, and the difference was statistically significant (p = .04). The mean time to exposure was 10 months. Plate fracture rate was 6 of 23 (26.1%) in dentulous patients versus 1 of 17 (5.9%) in edentulous patients. Gastrostomy tube dependence was 6 of 16 (38%) in group 1 versus 6 of 24 (25%) in group 2.

Conclusion

The “compartment approach” reduces plate exposure rate and gastrostomy tube dependence. Revascularized osseocutaneous reconstruction is still required in dentulous patients. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Intraoperative radiation therapy as an “early boost” in locally advanced head and neck cancer: Preliminary results of a feasibility study
Authors: Marucci Laura , Pichi Barbara , Iaccarino Giuseppe , Ruscito Paolo , Spriano Giuseppe , Arcangeli Giorgio
Published: February 2008

Background

The acute toxicity of intraoperative radiation therapy (IORT) delivered as an “early boost” after tumor resection in patients with locally advanced head and neck cancer was evaluated.

Methods

Twenty‐five patients were enrolled in the study. All patients underwent surgery with radical intent, and 17 had microvascular flap reconstruction. The IORT was delivered in the operating room. Twenty patients received adjuvant external beam radiation therapy (EBRT).

Results

Five patients experienced various degrees of complications in the postoperative period, all of which were treated conservatively. One patient had a partial flap necrosis after EBRT that was treated with flap removal. Six deaths were recorded during the mean follow‐up period of 8 months; none of the deaths were related to radiation treatment.

Conclusion

This feasibility study shows that the use of IORT as an early boost is feasible with no increase in acute toxicity directly attributable to radiation. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Pilot study: Volatile organic compounds as a diagnostic marker for head and neck tumors
Authors: Schmutzhard Joachim , Rieder Josef , Deibl Martina , Schwentner Ilona M. , Schmid Stefan , Lirk Philip , Abraham Irene , Gunkel Andreas R.
Published: February 2008

Background

In the last decade, the analysis of volatile organic compounds (VOC) has undergone a rapid development. In this pilot study, patients with HNSCC were tested with a proton transfer reaction‐mass spectrometry in order to establish a minimal invasive screening method.

Methods

Overall in a period of 2 years, 22 carcinoma patients were recruited for the study. All patients had a newly diagnosed histologically secured squamous cell carcinoma of the upper aerodigestive tract. These results were statistically compared with 3 control groups: healthy controls, high‐risk, and posttherapy patients.

Results

Two hundred nine different masses were measured; 188 of these were evaluated. The statistical workup of the 4 study groups produced 42 different masses, which showed a statistically significant difference from the carcinoma group compared with the control groups.

Conclusion

A screening method for HNSCC using VOC seems to be possible, but further investigation is necessary. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Horizontal supraglottic partial laryngectomy for selected squamous carcinoma of the vallecula
Authors: Laccourreye Laurent , Garcia Dominique , Ménard Madeleine , Brasnu Daniel , Laccourreye Ollivier , Holsinger F. Christopher
Published: February 2008

Background

Our aim was to determine the incidence of local control in patients with selected squamous carcinoma of the vallecula treated with horizontal supraglottic laryngectomy; to analyze the consequences of local recurrence in terms of nodal recurrence, distant metastasis, survival, causes of death, overall local control, and laryngeal preservation; and to identify any clinical factors predictive of these outcomes.

Methods

This was a retrospective nonrandomized case series in a university teaching hospital. An inception cohort of 95 previously untreated patients were followed until death or for a minimum of 5 years. According to the 2002 Union Internationale Contre le Cancer (UICC) staging classification system, the tumor was classified as T1, T2, and T3 in 13, 60, and 22 patients, respectively, while disease in 67 patients was considered to be in stages III to IV. All patients underwent a horizontal partial supraglottic partial laryngectomy. Ninety‐four patients had an associated neck dissection. An induction chemotherapy regimen was used in 91 patients; postoperative radiation therapy was given for 49 patients. The main outcome measures were local recurrence, nodal recurrence, distant metastasis, and survival.

Results

The 1‐, 3‐, and the 5‐year actuarial survival estimates were 86.3%, 64.2%, and 47.4%, respectively. Overall, the main causes of death were as follows: metachronous second primary tumor (47.2% of patients), intercurrent disease (16.7%), distant metastasis (15.3%), local recurrence (6.3%), and nodal recurrence, (4.2%). The 1‐, 3‐, and 5‐year actuarial local recurrence rates were 4.5%, 11%, and 11%, respectively. Nine patients developed a local recurrence; 3 were successfully salvaged. Using multivariate analysis, no single variable was found to increase the risk for local recurrence. The overall laryngeal preservation rate and local control rate were 89.5% (85/95) and 93.4% (89/95), respectively. Local recurrence was associated with a significant increase in nodal recurrence (p <.04) and distant metastasis (p = .03).

Conclusions

Based on this experience, horizontal partial supraglottic laryngectomy appears to be a valid approach for functional organ‐preservation in patients with selected T1–T3 SCC of the vallecula. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Outcomes following reirradiation of patients with head and neck cancer
Authors: Goldstein David P. , Karnell Lucy Hynds , Yao Min , Chamberlin G. Parker , Nguyen Thanh X. , Funk Gerry F.
Published: February 2008

Background

This study reports the outcomes for patients with head and neck cancer who received reirradiation with palliative or curative intent.

Methods

A retrospective review of 41 patients treated with curative (n = 28) or palliative (n = 13) reirradiation was conducted. Survival was calculated from the start of the reirradiation. Radiation‐related toxicities were classified according to Radiation Therapy Oncology Group criteria. Disease‐related problems included adverse events during or after reirradiation that were not directly related to reirradiation.

Results

The observed 1‐year survival for all patients was 39.0% (23.0% palliative, 46.3% curative). Median survival for all patients was 10.2 months. Seventy‐five percent of curative and 53.8% of palliative patients had grade 3 or 4 radiation‐related toxicities and/or major disease‐related problems.

Conclusion

A second course of radiotherapy in patients with head and neck cancer should be offered with a clear understanding that survival is poor and many of these patients will suffer severe radiation‐related or disease‐related insults to their quality of life during and after treatment. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
Lack of inducible nitric oxide synthase leads to increased hepatic apoptosis and decreased fibrosis in mice after chronic carbon tetrachloride administration
Authors: Aram Ghazaleh , Potter James J. , Liu Xiaopu , Torbenson Michael S. , Mezey Esteban
Published: February 2008

The role of nitric oxide (NO) in liver injury and fibrosis is unclear. The purpose of this study was to determine whether inducible NO synthase deficiency (iNOS−/−) affects liver injury and fibrosis produced in mice by chronic carbon tetrachloride (CCl4) administration. Wild-type (WT) or iNOS−/− mice were subjected to biweekly CCl4 injections over 8 weeks, whereas controls were given isovolumetric injections of olive oil. Serum aminotransferases were lower after CCl4 in the iNOS−/− than in the WT mice, which correlated with decreased necrosis on liver histology. There was increased apoptosis, a lower number of stellate cells, and a lesser degree of fibrosis after CCl4 in the iNOS−/− as compared with the WT mice. α1(I) collagen messenger RNA (mRNA) was markedly increased after CCl4 in the WT and to a significantly lesser extent in the iNOS−/− mice. Liver matrix metalloproteinase-9 (MMP-9) mRNA and MMP-2 mRNA were increased more in the WT than in the iNOS−/− mice after CCl4. Also tissue inhibitor metalloproteinase 1 (TIMP-1) mRNA was increased to a much greater extent in the WT than in the iNOS−/− mice after CCl4 (

P

< 0.05). However, MMP-9 and TIMP-1 protein, determined by western blot, were similarly increased after CCl4 in both groups of mice.

Conclusion:

NO protects against CCl4-induced apoptosis. In the absence of iNOS, there is decreased necrosis, increased apoptosis, and reduced liver fibrosis.
Transforming growth factor-β gene expression signature in mouse hepatocytes predicts clinical outcome in human cancer
Authors: Coulouarn Cédric , Factor Valentina M. , Thorgeirsson Snorri S.
Published: February 2008

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. The clinical heterogeneity of HCC, and the lack of good diagnostic markers and treatment strategies, has rendered the disease a major challenge. Patients with HCC have a highly variable clinical course, indicating that HCC comprises several biologically distinctive subgroups reflecting a molecular heterogeneity of the tumors. Transforming growth factor β (TGF-β) is known to exhibit tumor stage dependent suppressive (that is, growth inhibition) and oncogenic (that is, invasiveness) properties. Here, we asked if a TGF-β specific gene expression signature could refine the classification and prognostic predictions for HCC patients. Applying a comparative functional genomics approach we demonstrated that a temporal TGF-β gene expression signature established in mouse primary hepatocytes successfully discriminated distinct subgroups of HCC. The TGF-β positive cluster included two novel homogeneous groups of HCC associated with early and late TGF-β signatures. Kaplan-Meier plots and log-rank statistics indicated that the patients with a late TGF-β signature showed significantly (

P

< 0.005) shortened mean survival time (16.2 ± 5.3 months) compared to the patients with an early (60.7 ± 16.1 months) TGF-β signature. Also, tumors expressing late TGF-β-responsive genes displayed invasive phenotype and increased tumor recurrence. We also showed that the late TGF-β signature accurately predicted liver metastasis and discriminated HCC cell lines by degree of invasiveness. Finally, we established that the TGF-β gene expression signature possessed a predictive value for tumors other than HCC.

Conclusion:

These data demonstrate the clinical significance of the genes embedded in TGF-β expression signature for the molecular classification of HCC.
Extranodal NK/T‐cell lymphoma: diagnosis and treatment cues
Authors: Suzuki Ritsuro , Takeuchi Kengo , Ohshima Koichi , Nakamura Shigeo
Published: February 2008

Extranodal NK/T‐cell lymphoma, nasal type (ENKL) is mostly endemic to East Asia. It predominantly occurs in the nasal or paranasal areas and less frequently in the skin. Most of the tumours show NK‐cell, but rarely T‐cell, phenotypes. The Epstein–Barr virus (EBV) genome can be usually detected in lymphoma cells. Geographic localization of ENKL matches the endemic distribution of EBV, suggesting that EBV plays an important role in lymphomagenesis. Originally, NK‐cell and T‐cell types were believed to present the same clinicopathologic characteristics, but recent data suggest more aggressive characteristics for the NK‐cell phenotype. Although ENKL is sensitive to radiotherapy, it shows a poorer response to chemotherapeutic agents than other lymphomas due to expression of p‐glycoprotein. Therefore, new therapeutic approaches must be considered. Several new clinical trials are now being conducted in East Asia. Copyright © 2008 John Wiley & Sons, Ltd.
Mechanical behavior of hydroxyapatite biomaterials: An experimentally validated micromechanical model for elasticity and strength
Authors: Fritsch Andreas , Dormieux Luc , Hellmich Christian , Sanahuja Julien
Published: February 2008

Hydroxyapatite (HA) biomaterials production has been a major field in biomaterials science and biomechanical engineering. As concerns prediction of their stiffness and strength, we propose to go beyond statistical correlations with porosity or empirical structure–property relationships, as to resolve the material‐immanent microstructures governing the overall mechanical behavior. The macroscopic mechanical properties are estimated from the microstructures of the materials and their composition, in a homogenization process based on continuum micromechanics. Thereby, biomaterials are envisioned as porous polycrystals consisting of HA needles and spherical pores. Validation of respective micromechanical models relies on two independent experimental sets: biomaterial‐specific macroscopic (homogenized) stiffness and uniaxial (tensile and compressive) strength predicted from biomaterial‐specific porosities, on the basis of biomaterial‐independent (“universal”) elastic and strength properties of HA, are compared with corresponding biomaterial‐specific experimentally determined (acoustic and mechanical) stiffness and strength values. The good agreement between model predictions and the corresponding experiments underlines the potential of micromechanical modeling in improving biomaterial design, through optimization of key parameters such as porosities or geometries of microstructures, in order to reach the desired values for biomaterial stiffness or strength. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Effect of adding sodium hexametaphosphate liquefier on basic properties of calcium phosphate cements
Authors: Hesaraki S. , Zamanian A. , Moztarzadeh F.
Published: February 2008

Sodium hexametaphosphate (Na‐HMP) is a common liquefying agent widely used in the ceramics industry for modifying the rheological behavior of ceramic slurries. The objective of this study was to investigate the influence of Na‐HMP on several properties of calcium phosphate cements (CPCs). Various types of CPCs were prepared by mixing the same powder, namely, a mixture of tetracalcium phosphate and dicalcium phosphate anhydrate, with various liquids, namely, distilled water, Na2HPO4 solutions, and Na‐HMP solutions. The setting time, mechanical strength, rheological properties, and injectability of the cement pastes were examined in this work. Also, X‐ray diffractometry (XRD) and scanning electron microscopy (SEM) techniques were employed for phase analysis and morphological evaluations, respectively. The results showed that, compared to CPCs made with water and Na2HPO4 solutions, the CPC pastes made with Na‐HMP solutions had improved stability and injectability but prolonged setting times. The XRD and SEM studies showed that Na‐HMP inhibited the growth of apatite crystals during soaking of the cements in Ringer's solution. Thus, the CPC made with Na‐HMP solution had lower compressive strength than those made with water or Na2HPO4 solutions. Although Na‐HMP could improve the injectability and stability of the CPC paste, it impaired other basic properties of the cement. Thus, it is not an appropriate liquefier additive. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Side effects of a non‐peroxide‐based home bleaching agent on dental enamel
Authors: Wang Xiaojie , Mihailova Boriana , Klocke Arndt , Fittschen Ursula E. A. , Heidrich Stefanie , Hill Mathias , Stosch Rainer , Güttler Bernd , Broekaert José A. C. , Bismayer Ulrich
Published: February 2008

Changes in the chemistry and structure of enamel due to a non‐peroxide‐based home bleaching product (Rapid White) were studied in vitro using attenuated total reflectance‐infrared spectroscopy, Raman spectroscopy, electron probe microanalysis, flame atomic absorption spectroscopy, and total reflection X‐ray fluorescence. The results revealed that the citric‐acid‐containing gel‐like component of the bleaching system substantially impacts on the dental hard tissue. Enamel is affected on several levels: (i) the organic component is removed from superficial and deeper enamel layers and remnants of the bleaching gel are embedded in the emptied voids; (ii) cracks and chemical inhomogeneities with respect to Ca and P occur on the surface; and (iii) within a submicron layer of enamel, the CaO bond strength in apatite decreases, thus enhancing calcium leakage from the bleached enamel hard tissue. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Preparation and in vitro characterization of novel bioactive glass ceramic nanoparticles
Authors: Hong Zhongkui , Reis Rui L. , Mano João F.
Published: February 2008

SiO2‐CaO‐P2O5 ternary bioactive glass ceramic (BGC) nanoparticles with different compositions were prepared via a three‐step sol‐gel method. Polyethylene glycol was selected to be used as the surfactant to improve the dispersion of the nanoparticles. The morphology and composition of these BGC nanoparticles were observed by ESEM and EDX. All the BGC particles obtained in this method were about 20 nm in diameter. XRD analysis demonstrated that the different compositions can result in very different crystallinities for the BGC nanoparticles. Bioactivity tests in simulated body fluid solution (SBF), and degradability in phosphate buffer solution (PBS), were performed in vitro. SEM, EDX, and XRD were employed to monitor the surface variation of neat poly(L‐lactic acid), PLLA, foam and PLLA/BGC porous scaffolds during incubation. The BGC nanoparticles with lower phosphorous and relative higher silicon content exhibited enhanced mineralization capability in SBF and a higher solubility in PBS medium. Such novel nanoparticles may have potential to be used in different biomedical applications, including tissue engineering or the orthopedic field. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Activation of human leukocytes on tantalum trabecular metal in comparison to commonly used orthopedic metal implant materials
Authors: Schildhauer T. A. , Peter E. , Muhr G. , Köller M.
Published: February 2008

We analyzed leukocyte functions and cytokine response of human leukocytes toward porous tantalum foam biomaterial (Trabecular Metal™, TM) in comparison to equally sized solid orthopedic metal implant materials (pure titanium, titanium alloy, stainless steel, pure tantalum, and tantalum coated stainless steel). Isolated peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophil leukocytes (PMN) were cocultured with equally sized metallic test discs for 24 h. Supernatants were analyzed for cytokine content by enzyme‐linked immunosorbent assay. Compared to the other used test materials there was a significant increase in the release of IL (interleukin)‐1ra and IL‐8 from PMN, and of IL‐1ra, IL‐6, and TNF‐α from PBMC in response to the TM material. The cytokine release correlated with surface roughness of the materials. In contrast, the release of IL‐2 was not induced showing that mainly myeloid leukocytes were activated. In addition, supernatants of these leukocyte/material interaction (conditioned media, CM) were subjected to whole blood cell function assays (phagocytosis, chemotaxis, bacterial killing). There was a significant increase in the phagocytotic capacity of leukocytes in the presence of TM‐conditioned media. The chemotactic response of leukocytes toward TM‐conditioned media was significantly higher compared to CM obtained from other test materials. Furthermore, the bactericidal capacity of whole blood was enhanced in the presence of TM‐conditioned media. These results indicate that leukocyte activation at the surface of TM material induces a microenvironment, which may enhance local host defense mechanisms. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Synthesis, self‐assembly in water, and cytotoxicity of MPEG‐block‐PLLA/DX conjugates
Authors: Xie Zhigang , Lu Tiancheng , Chen Xuesi , Zheng Yonghui , Jing Xiabin
Published: February 2008

Docetaxel (DX) is one of the most effective antineoplastic drugs. Its current clinical administration is limited because of its hydrophobicity and serious side effects. A polymer/DX conjugate is designed and successfully prepared to solve these problems. It is monomethoxy‐poly(ethylene glycol)‐block‐poly(L‐lactide)/DX (MPEG‐PLLA/DX). It was synthesized by reacting DX with carboxyl‐terminated copolymer MPEG‐PLLA, which was prepared by reacting succinic anhydride with hydroxyl‐terminated copolymer monomethoxy‐poly(ethylene glycol)‐block‐poly(L‐lactide) (MPEG‐PLLA). Its structure and molecular weight was confirmed by 1H NMR and GPC. The MPEG‐PLLA/DX micelles in aqueous solution were prepared using a solvent displacement method and characterized by dynamic light scattering for size and size distribution, and by transmission electron microscopy for surface morphology. Its antitumor activity against HeLa cancer cells evaluated by MTT assay showed that it had a similar antitumor activity to pure DX at the same drug content. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
New class of anti‐microbial agents: Synthesis, characterization, and anti‐microbial activities of metal chelated polyurea
Authors: Ahamad Tansir , Kumar Vikrant , Nishat Nahid
Published: February 2008

A new class of metal chelated polyurea have been synthesized by the reaction of toluene 2,4‐diisocyanate (TDI) with chelated Schiff base diamines. The synthesized polyurea have been characterized by analytical, spectral, and thermal analysis. The results of TGA ascribed that [Cu(II)‐PoUA] show better heat resistant properties than other metals chelated polyurea. The antibacterial activities of all the synthesized polymers were determined using the shaking flask method, where 30 mg/mL concentrations of each compound were tested against 105 CFU/mL solutions of S. aureus, E. coli, B. subtillis, S. typhi. The number of viable bacteria was calculated by using the spread plate method on agar plates and the number of viable bacteria was counted after 24 h of incubation period at 37°C. All the polymers showed good antibacterial activity. The Cu(II) chelated polyurea show higher zone of inhibition then other due to higher stability constant and may be used in biomedical applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Boronate‐containing polymer brushes: Characterization, interaction with saccharides and mammalian cancer cells
Authors: Ivanov Alexander E. , Eccles John , Panahi Homayon Ahmad , Kumar Ashok , Kuzimenkova Marina V. , Nilsson Lars , Bergenståhl Björn , Long Nick , Phillips Gary J. , Mikhalovsky Sergey V. , Galaev Igor Yu , Mattiasson Bo
Published: February 2008

Boronate‐containing polymer brushes were synthesized by free radical copolymerization of N,N‐dimethylacrylamide (DMAA) and N‐acryloyl‐m‐phenylboronic acid (NAAPBA) (9:1) on the surface of 3‐mercaptopropyl‐silylated glass plates and capillaries. The brushes were characterized with time‐of‐flight secondary ion mass‐spectrometry (ToF SIMS), atomic force microscopy and contact angle measurements. Fructose caused a well‐expressed drop spreading on the surface of copolymer‐grafted glass, due to the strong interaction with the boronate groups. Sedimentation of murine hybridoma cells M2139 or human myeloid leukemia cells KG1 onto the DMAA‐NAAPBA copolymer‐grafted glass plates from 10 mM phosphate buffer solution (pH 8.0) resulted in the cell adhesion. The adhered M2139 and KG1 cells could be quantitatively detached from the grafted plates with 0.1M fructose, which competed with cell surface carbohydrates for binding to the boronates. Evaluation of the binding strength between M2139 cells and the copolymer brush was performed by exposure of the adhered cells to a shear stress. Detachment of a fraction of 18% of the adhered M2139 cells was obtained at a shear force of 1400–2800 pN/cell generated by the running phosphate buffer (pH 8.0), whereas the remaining adhered cells (70%) could be detached with 0.1M fructose dissolved in the same buffer. Possible applications of the boronate‐containing polymer brushes to affinity cell separation can be based upon the facile recovery of the attached cells. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Enhancement of the biological activity of BMP‐2 by synthetic dextran derivatives
Authors: Degat Marie‐Christelle , Dubreucq Guy , Meunier Alain , Dahri‐Correia Latifa , Sedel Laurent , Petite Herve , Logeart‐Avramoglou Delphine
Published: February 2008

In the present study, we explored the binding capacity of synthetic heparin‐like dextran derivatives to recombinant human bone morphogenetic protein 2 (BMP‐2), a heparin‐binding osteoinductive growth factor. Affinity electrophoresis analysis provided evidence that carboxymethylated dextran polymers grafted with high amounts of benzylamide groups (named DMCB) interact with BMP‐2. The capability of such polysaccharides to potentiate the growth factor biological activity was then investigated. In vitro, DMCB dose‐dependently promoted osteoblast differentiation induced by BMP‐2 in C2C12 myoblasts more efficiently than heparin. A screening study provided evidence that the potentiating effects of the dextran derivatives on the BMP‐2‐induced alkaline phosphatase activity improved with their benzylamide groups content and, therefore, with their affinity for the growth factor. The biological activity of BMP‐2 was monitored in the culture medium after 6 days using C2C12 cells (containing a BMP sensitive luciferase reporter gene). Like heparin, DMCB sustained the biological activity of the growth factor; this result suggests that the formation of the BMP‐2/DMCB complex may protect the protein from being inactivated. In rats in vivo, DMCB also stimulated ectopic calcification mediated by BMP‐2. These data indicate that dextran‐based polysaccharides prolong the half‐life of the growth factor and promote its biological activity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Endothelial cell migration in human plasma is enhanced by a narrow range of added sphingosine 1‐phosphate: Implications for biomaterials design
Authors: Alford Shannon K. , Kaneda Megan M. , Wacker Bradley K. , Elbert Donald L.
Published: February 2008

Sphingosine 1‐phosphate (S1P) promotes endothelial cell migration in vitro and may potentially impact the endothelialization of implanted biomaterials. However, the effects of S1P on endothelial cells (EC) in flowing blood could be negligible due to preactivation of signaling cascades. We previously developed biomaterials that release S1P and wished to determine through in vitro experiments the extent to which EC respond to S1P added to human platelet poor plasma. We found that addition of 200 nM S1P to platelet poor plasma significantly increased cell migration in two migration models. A lower concentration of S1P added to plasma (100 nM) did not increase endothelial cell migration rates, while the cell migration response was saturated above 200 nM S1P. Expression of the main S1P receptor in EC, S1P1, was elevated in plasma compared to low serum medium, but addition of VEGF or fluid flow elicited a further increase in S1P1 mRNA, consistent with the synergistic effects observed between S1P, VEGF, and fluid flow. Thus, sustained delivery of S1P from biomaterials might only enhance endothelial cell migration if the concentration of S1P at the surface of the material stimulated adjacent EC to the same extent as ≈200 nM S1P added to plasma. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Assembly of multilayer PSS/PAH membrane on coherent alginate/PLO microcapsule for long‐term graft transplantation
Authors: Leung Andy , Trau Matt , Nielsen Lars Keld
Published: February 2008

Conventional alginate/poly‐L‐ornithine (AP) membranes used to immunoisolate foreign tissue transplants fail in long‐term transplantations of immortal cell lines. We have developed a novel layer‐by‐layer (LbL) membrane using polystyrene sulfonate and polyallylamine hydrochloride (PSS/PAH) on top of the coherent AP membrane. Assembly of the LbL membrane was followed by electrophoresis, and the surface morphologies and structure were characterized and examined by cryo‐scanning electron microscope and transmission electron microscopy. Unlike the standard AP membrane, the LbL membrane withstood the internal pressure generated by continuous cell proliferation of microencapsulated HEK‐293 and Min‐6 cells. The new membrane did not affect insulin secretion or diffusion by Min‐6 cells. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
A biomechanical and histological analysis of standard versus hydroxyapatite‐coated pins for external fixation
Authors: Moroni Antonio , Cadossi Matteo , Romagnoli Matteo , Faldini Cesare , Giannini Sandro
Published: February 2008

This sheep study was designed to make a comparative evaluation of two external fixation pin types each with and without hydroxyapatite (HA) coating. The two pins had different taper, pitch, and self drilling capabilities. Twenty Orthofix standard, self‐tapping pins (group A), 20 Orthofix HA‐coated, self‐tapping pins (group B), 20 X‐caliber, self‐drilling, self‐tapping pins (group C), and 20 X‐caliber HA‐coated, self‐drilling, self‐tapping pins (group D) were selected. Four pins were implanted in the right femurs of 20 adult sheep that were euthanized at 6 weeks. Mean pin insertion torque was 2745 ± 822 Nmm in group A, 2726 ± 784 Nmm in group B, 2818 ± 552 Nmm in group C, and 2657 ± 732 Nmm in group D (ns). Mean pin extraction torque was 1567 ± 541 Nmm in group A, 2524 ± 838 Nmm in group B, 1650 ± 650 Nmm in group C, and 2517 ± 726 Nmm in group D. HA‐coated pins (group B and D) had a significantly greater mean pin extraction torque compared to similar uncoated pins (group A and C) (p < 0.0005). Histological analysis showed good osteointegration of the two coated pin types. This study shows that HA‐coating is more important for optimal pin fixation than the particular combination of design parameters used in each pin type. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Inhibition of mineralization by a calcium zirconium phosphate coating
Authors: Bernstein Anke , Nöbel Doreen , Mayr Hermann O. , Göbel Felix , Berger Georg , Ploska Ute , Gildenhaar Renate , Brandt Jörg
Published: February 2008

Bioactive ceramics used as coating materials combine the conductive properties of a bioceramic with the mechanical stability of the metal implant. We studied a calcium zirconium phosphate‐containing coating material, FA‐CZP [Ca5(PO4)3F, CaZr4(PO4)6], that is relatively insoluble in the biological milieu. The reaction of bone to this material was investigated histologically and histomorphometrically in an animal trial. Cylindrical Ti6Al4V specimens that had been coated with FA‐CZP by plasma spraying were implanted in the femoral condyles of rabbits. The implants were left in place for 2, 4, 6, 12, and 14 weeks. FA‐CZP led to impaired mineralization of the newly formed bone at the interface. Noncalcified osteoid was found throughout the whole study period. The layer seemed to become thicker with time. The mineralization disorder is evidently caused by zirconium ions. The presence of zirconium in the osteoid in contact with the implant was demonstrated by means of two different staining methods. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Thin films of oriented collagen fibrils for cell motility studies
Authors: Amyot Franck , Small Alex , Boukari Hacène , Sackett Dan , Elliott John , McDaniel Dennis , Plant Anne , Gandjbakhche Amir
Published: February 2008

Collagen films with oriented fibrils mimic tissues that have been remodeled by fibroblasts, which naturally tend to orient collagen fibrils in vivo. We have prepared thin films of ordered fibrils of collagen I, a major component of the extracellular matrix. The films were prepared by modifying a technique previously used to produce collagen I films for studies of cell morphology and intracellular signaling. By modifying the drying step, we were able to produce thin monolayers of collagen fibrils with consistent orientations over macroscopic (>100 μm) distances. We quantified the degree of orientation of the collagen fibrils using Fourier analysis of optical microscopy images. We also conducted experiments with vascular endothelial cells, and found that cell orientation and migration are well‐correlated with fibril orientation. Using polarized cells, we showed oriented thin collagen film induces natural migration along the fibrils without using any sort of attractor. Taken together, these results demonstrate additional functionality and physiological relevance for a class of films being successfully applied in a variety of cell biology experiments. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Bone formation and resorption in patients after implantation of β‐tricalcium phosphate blocks with 60% and 75% porosity in opening‐wedge high tibial osteotomy
Authors: Tanaka Takaaki , Kumagae Yoshio , Saito Mitsuru , Chazono Masaaki , Komaki Hirokazu , Kikuchi Takahiro , Kitasato Seiichiro , Marumo Keishi
Published: February 2008

Most of the implanted porous β‐tricalcium phosphate (β‐TCP) can be resorbed. However, β‐TCP block with 75% porosity is inadequate for weight‐bearing sites until bone incorporation occurs. Thus, the authors have recently developed β‐TCP block with 60% porosity, which is approximately sevenfold greater in terms of compressive strength than that of β‐TCP with 75% porosity. The authors investigated bone formation and resorption of β‐TCP after implantation in patients of β‐TCP blocks with two different porosities. From May 2003 to November 2004, medial opening high tibial osteotomy was performed in 25 patients with a mean age of 66 years. The opened defect was fixed with a Puddu plate. Then 6–8 cm3 of β‐TCP block with 75% porosity was used to fill the cancellous bone defect, except on the medial side where 2.83–3.18 cm3 of wedge‐shaped β‐TCP block with 60% porosity was implanted. At least 2 years after surgery, the 25 patients had no correction loss, and bone formation was noted in all cases. Complete or nearly complete resorption of β‐TCP with 60 and 75% porosity was obtained within 3.5 years. Thirteen biopsy samples obtained from the 60% porosity implantation sites showed good lamellar bone formation, and the percentage of β‐TCP remaining relative to the newly formed bone plus β‐TCP ranged from 0.3 to 14.5%, with a mean of 6.7%. The authors suspect that mechanical stress loading to the medial side of the tibia facilitated bone formation and resorption of β‐TCP with 60% porosity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Exclusive use of acid citrate dextrose for anticoagulation during extracorporeal photopheresis in patients with contraindications to heparin: An effective protocol
Authors: Nedelcu Elena , Ziman Alyssa , Fernando Leonor P. , Cook Kris , Bumerts Pam , Schiller Gary
Published: February 2008

Extracorporeal photopheresis (ECP) routinely uses heparin for anticoagulation. For patients with contraindications to heparin, alternative anticoagulation using acid citrate dextrose (ACD‐A) has been reported to be safe and effective. However, detailed ECP protocols that exclusively use ACD‐A anticoagulation and minimize citrate toxicity have not yet been published. We report a protocol that completely replaces heparin with ACD‐A for ECP, which was developed at the University of California, Los Angeles (UCLA), and our experience since its implementation. ECP was performed with the UVAR XTS photopheresis system using ACD‐A and control of the rate of citrate infusion. Calcium gluconate solution was administered prophylactically and as needed for symptoms of citrate toxicity. The medical records of patients who underwent ECP using the ACD‐A protocol between January 2003 and July 2006 were reviewed. The incidence and severity of citrate toxicity and the technical data for all procedures were analyzed. During this period, 94 ECP procedures were performed with ACD‐A anticoagulation on five patients. All patients tolerated the procedures well without significant complications. Only minimal symptoms of citrate toxicity (grade 1) were observed in 24.5% of all procedures; symptoms resolved promptly following administration of additional calcium gluconate. In conclusion, an effective protocol for ECP using ACD‐A anticoagulation exclusively in patients with contraindications to heparin employs continuous monitoring of flow rates and prophylactic administration of calcium gluconate to minimize citrate toxicity. J. Clin. Apheresis, 2008. Published 2008 Wiley‐Liss, Inc.
Inhibition of Cdc7/Dbf4 kinase activity affects specific phosphorylation sites on MCM2 in cancer cells
Authors: Charych Deborah H. , Coyne Mazie , Yabannavar Asha , Narberes Jamie , Chow Sylvia , Wallroth Marco , Shafer Cynthia , Walter Annette O.
Published: February 2008

The Cdc7/Dbf4 kinase is required for initiation of DNA replication and also plays a role in checkpoint function in response to replication stress. Exactly how Cdc7/Dbf4 mediates those activities remains to be elucidated. Cdc7/Dbf4 physically interacts with and phosphorylates the minichromosome maintenance complex (MCM), such as MCM2, MCM4 and MCM6. Cdc7/Dbf4 activity is required for association of Cdc45 followed by recruitment of DNA polymerase on the chromatin. Using high resolution mass spectrometry, we identified six phosphorylation sites on MCM2, two of them have not been described before. We provide evidence that Cdc7/Dbf4 mediates phosphorylation on serine 108 and serine 40 on human MCM2 in vitro and in vivo in cancer cells in the absence of DNA damage. Antibodies specific to pS108 or pS40 confirmed the sites and established useful read‐outs for inhibition of Cdc7/Dbf4. This report demonstrates the utility of an in vitro to in vivo workflow utilizing immunoprecipitation and mass spectrometry to map phosphorylation sites on endogenous kinase substrates. The approach can be readily generalized to identify target modulation read‐outs for other potential kinase cancer targets. J. Cell. Biochem. 104: 1075–1086, 2008. © 2008 Wiley‐Liss, Inc.
MAPRes: An efficient method to analyze protein sequence around post‐translational modification sites
Authors: Ahmad Ishtiaq , Hoessli Daniel C. , Qazi Wajahat M. , Khurshid Ahmed , Mehmood Abid , Walker‐Nasir Evelyne , Ahmad Munir , Shakoori Abdul R. , Nasir‐ud‐Din
Published: February 2008

Functional switches are often regulated by dynamic protein modifications. Assessing protein functions, in vivo, and their functional switches remains still a great challenge in this age of development. An alternative methodology based on in silico procedures may facilitate assessing the multifunctionality of proteins and, in addition, allow predicting functions of those proteins that exhibit their functionality through transitory modifications. Extensive research is ongoing to predict the sequence of protein modification sites and analyze their dynamic nature. This study reports the analysis performed on phosphorylation, Phospho.ELM (version 3.0) and glycosylation, OGlycBase (version 6.0) data for mining association patterns utilizing a newly developed algorithm, MAPRes. This method, MAPRes (Mining Association Patterns among preferred amino acid residues in the vicinity of amino acids targeted for post‐translational modifications), is based on mining association among significantly preferred amino acids of neighboring sequence environment and modification sites themselves. Association patterns arrived at by association pattern/rule mining were in significant conformity with the results of different approaches. However, attempts to analyze substrate sequence environment of phosphorylation sites catalyzed for Tyr kinases and the sequence data for O‐GlcNAc modification were not successful, due to the limited data available. Using the MAPRes algorithm for developing an association among PTM site with its vicinal amino acids is a valid method with many potential uses: this is indeed the first method ever to apply the association pattern mining technique to protein post‐translational modification data. J. Cell. Biochem. 104: 1220–1231, 2008. © 2008 Wiley‐Liss, Inc.
Coexpression of osteogenic and adipogenic differentiation markers in selected subpopulations of primary human mesenchymal progenitor cells
Authors: Ponce M.L. , Koelling S. , Kluever A. , Heinemann D.E.H. , Miosge N. , Wulf G. , Frosch K.‐H. , Schütze N. , Hufner M. , Siggelkow H.
Published: February 2008

Knowledge of the basic mechanisms controlling osteogenesis and adipogenesis might provide new insights into the prevention of osteoporosis and age‐related osteopenia. With the help of magnetic cell sorting and fluorescence activated cell sorting (FACS), osteoblastic subpopulations of mesenchymal progenitor cells were characterized. Alkaline phosphatase (AP) negative cells expressed low levels of osteoblastic and adipocytic markers. AP positive cells expressed adipocytic markers more strongly than the AP negative cell populations, thus suggesting that committed osteoblasts exhibit a greater adipogenic potential. AP negative cells differentiated to the mature osteoblastic phenotype, as demonstrated by increased AP‐activity and osteocalcin secretion under standard osteogenic culture conditions. Surprisingly, this was accompanied by increased expression of adipocytic gene markers such as peroxisome proliferator‐activated receptor‐γ2, lipoprotein lipase and fatty acid binding protein. The induction of adipogenic markers was suppressed by transforming growth factor‐β1 (TGF‐β1) and promoted by bone morphogenetic protein 2 (BMP‐2). Osteogenic culture conditions including BMP‐2 induced both the formation of mineralized nodules and cytoplasmic lipid vacuoles. Upon immunogold electron microscopic analysis, osteoblastic and adipogenic marker proteins were detectable in the same cell. Our results suggest that osteogenic and adipogenic differentiation in human mesenchymal progenitor cells might not be exclusively reciprocal, but rather, a parallel event until late during osteoblast development. J. Cell. Biochem. 104: 1342–1355, 2008. © 2008 Wiley‐Liss, Inc.
Gene expression profiling of macrophages following mice treatment with an immunomodulator medication
Authors: de Oliveira Carolina Camargo , de Oliveira Simone Martins , Goes Viviane M. , Probst Christian M. , Krieger Marco Aurelio , Buchi Dorly de Freitas
Published: February 2008

Canova (CA) is a complex homeopathic medication used in diseases where the immune system is depressed. Previous studies demonstrated that it is neither toxic nor mutagenic and activates macrophages. We now evaluate CA effects on cytokine production and gene expression from mice macrophages. The global view of changes in expression of genes with known functions can provide a vivid picture of the way in which cell adapts to a changing environment or a challenge. We found a decrease in IL‐2 and IL‐4 production and a differential expression in 147 genes from CA group. These genes are mainly involved in transcription/translation, cell structure and dynamics, immune response, cytoprotection, enzymatic process, and receptors/ligands. With gene expression analysis we state that this medication provokes a reaction that involves alterations in gene expression profile mainly in the ones involved with macrophages activation, corroborating the laboratorial research and the clinical data. J. Cell. Biochem. 104: 1364–1377, 2008. © 2008 Wiley‐Liss, Inc.
Isolation and characterization of a putative liver progenitor population after treatment of fetal rat hepatocytes with TGF‐Beta
Authors: del Castillo Gaelle , Álvarez‐Barrientos Alberto , Carmona‐Cuenca Irene , Fernández Margarita , Sánchez Aránzazu , Fabregat Isabel
Published: February 2008

The “in vitro” establishment of a physiological model of bipotential liver progenitors would be useful for analyzing the molecular mechanisms involved in regulating growth and differentiation, as well as studying their potential role/s in liver physiology and pathology. The transforming growth factor‐beta (TGF‐β) induces de‐differentiation of fetal rat hepatocytes (FH), concomitant with changes in morphology. The aim of this work was to isolate and characterize this population of TGF‐β‐treated fetal hepatocytes (TβT‐FH) and test whether they can behave as liver progenitors. The TβT‐FH isolated cell lines show high expression of Thy‐1 and low expression of c‐Kit. They express liver‐specific proteins, such as albumin and alpha‐fetoprotein, and mesenchymal markers, such as vimentin. TβT‐FH maintain expression of the hnf3β gene, but lose expression of hnf1β, hnf4, and hnf6. They express c‐met and show an increase in proliferation in response to HGF. Interestingly, the transdifferentiation process is coincident with changes in the expression of genes related to the oxidative metabolism. TβT‐FH cultured in the presence of EGF + DMSO change morphology, towards epithelial cells, gaining expression of CK19 and c‐Kit, markers found in hepatoblasts and bile duct cells. Furthermore, TβT‐FH form duct‐like structures when cultured on Matrigel. TβT‐FH show also potential to revert to an hepatocyte phenotype when submitted to a long‐term “in vitro” differentiation protocol towards hepatocytic lineage. In summary, our results support the hypothesis that hepatocytes can function as facultative liver stem cells and demonstrate that TGF‐β might play an essential role in the transdifferentiation process. J. Cell. Physiol. 215: 846–855, 2008. © 2008 Wiley‐Liss, Inc.