bluuebunny/crossref_metadata_2025 huggingface dataset:
Low frequency of HLA haplotype loss associated with loss of heterozygocity in chromosome region 6p21 in clear renal cell carcinomas
Authors: Maleno Isabel , Nevot Miguel Angel Lopez , Seliger Barbara , Garrido Federico
Published: February 2004

HLA class I loss or downregulation is a widespread mechanism used by tumor cells to avoid tumor recognition by cytotoxic T lymphocytes favoring tumor immune escape. Multiple molecular mechanisms are responsible for these altered HLA class I tumor phenotypes. It has been described in different epithelial tumors that loss of heterozygosity (LOH) at chromosome region 6p21.3 is a frequent mechanism that leads to HLA haplotype loss, ranging between 40 and 50%, depending on the tumor entity analyzed. Here we have tested the frequency of LOH at 6p21 chromosome region in Renal Cell Carcinomas (RCC) of the clear cell and chromophobe subtype. A low frequency of HLA haplotype loss (6.6%) was found in clear cell RCC. These data significantly differ from those reported in other epithelial tumors. In contrast, in RCC of chromophobe subtype this frequency was 10 times higher (3 out of 5 cases analyzed). These results indicate that LOH at 6p21.3 is not a frequent mechanism that leads to HLA class I abnormalities in clear cell RCC. In addition, the chromophobe RCC subtypes differ not only in histopathological criteria but also in the frequency of LOH‐mediating HLA class I alterations. These results might help to understand the significantly different biological behavior of both RCC subtypes. © 2004 Wiley‐Liss, Inc.
Coamplified and overexpressed genes at ERBB2 locus in gastric cancer
Authors: Varis Asta , Zaika Alexander , Puolakkainen Pauli , Nagy Balint , Madrigal Irene , Kokkola Arto , Väyrynen Aki , Kärkkäinen Päivi , Moskaluk Christopher , El‐Rifai Wa'el , Knuutila Sakari
Published: February 2004

DNA copy number amplification at the chromosomal region of 17q is frequent in gastric cancer. Recently 17q21 was identified as the critical region for the amplicon formation because this region harbors the ERBB2 oncogene and several other targets, such as TOP2A and DARPP32. In our study, we characterized the amplification (52 cases) and expression (29 cases) levels of ERBB2, TOP2A and DARPP32 in gastric cancer samples. These 3 genes were concomitantly amplified in 17% of the intestinal type of gastric adenocarcinoma. However, the expression levels were independent, showing overexpression of DARPP32 (48%), TOP2A (17%) and ERBB2 (3%) studied by quantitative real‐time PCR. The most frequently overexpressed gene, DARPP32, exhibited strong protein overexpression in 45% (30/66) of the cases in immunohistochemical study of gastric cancer tumor tissue array. Additional studies are required to thoroughly understand the biological significance of these genes in gastric cancer. © 2004 Wiley‐Liss, Inc.
Expression of cancer testis antigens in pancreatic carcinoma cell lines, pancreatic adenocarcinoma and chronic pancreatitis
Authors: Kubuschok Boris , Xie Xiaoxiun , Jesnowski Ralf , Preuss Klaus‐Dieter , Romeike Bernd F.M. , Neumann Frank , Regitz Evi , Pistorius Georg , Schilling Martin , Scheunemann Peter , Izbicki Jakob R. , Löhr J.‐Matthias , Pfreundschuh Michael
Published: February 2004

In order to define antigens that might be suitable as vaccines for pancreatic carcinoma, we investigated the composite expression of 10 cancer testis (CT) antigens (SCP‐1, NY‐ESO‐1, SSX‐1, SSX‐2, SSX‐4, GAGE, MAGE‐3, MAGE‐4, CT‐7 and CT‐8) by Reverse Transcriptase‐PCR (RT‐PCR) in fresh biopsies of human pancreatic adenocarcinoma, chronic pancreatitis and pancreatic carcinoma cell lines. While all CT genes were frequently expressed in cell lines derived from pancreatic cancer, no expression of MAGE‐3, SSX‐1, SSX‐2, NY‐ESO‐1 and CT‐7 was detected in fresh tumor biopsies, and MAGE‐4 (1/52), SSX‐4 (1/39) and CT‐8 (2/41) were only rarely expressed. In contrast, HOM‐TES‐14/SCP‐1 was expressed in 48% (29/61) and GAGE in 21% (13/61) of cases, respectively. One CT gene was expressed by 59% (75% in male, 46% in female patients; p = 0.05) and 2 or more CT genes by 15% of the samples. SCP‐1 protein expression correlated well with mRNA expression. While SCP‐1 and GAGE were absent in normal pancreas, they were found in 2/8 (SCP‐1) and 1/8 (GAGE) samples of chronic pancreatitis, respectively, supporting the concept of chronic pancreatitis as a premalignant condition. SCP‐1 and GAGE represent promising candidates for vaccine development in pancreatic carcinoma. Whether SCP‐1 and GAGE expression identify cases of chronic pancreatitis with a high risk of malignant transformation remains to be shown. © 2004 Wiley‐Liss, Inc.
Genetic and epigenetic inactivation of tax gene in adult T‐cell leukemia cells
Authors: Takeda Satoshi , Maeda Michiyuki , Morikawa Shigeru , Taniguchi Yuko , Yasunaga Jun‐ichirou , Nosaka Kisato , Tanaka Yuetsu , Matsuoka Masao
Published: February 2004

To clarify the status of tax gene, we analyzed human T‐cell leukemia virus type‐I (HTLV‐I) associated cell lines and fresh adult T‐cell leukemia (ATL) cells. We compared 2 types of HTLV‐I associated cell lines: one was derived from leukemic cells (leukemic cell line) and the other from nonleukemic cells (nonleukemic cell line). Although all nonleukemic cell lines expressed Tax, it could not be detected in 3 of 5 leukemic cell lines, in which nonsense mutation or deletion (60 bp) of tax genes, and DNA methylation in 5′‐LTR were identified as the responsible changes. We found such genetic changes of the tax gene in 5 of 47 fresh ATL cases (11%). The tax gene transcripts could be detected in 14 of 41 fresh ATL cases (34%) by RT‐PCR. In ATL cases with genetic changes that could not produce Tax protein, the tax gene was frequently transcribed, suggesting that such cells do not need the transcriptional silencing. Although DNA methylation of 5′‐LTR was detected in the fresh ATL cases (19 of 28 cases; 68%), the complete methylation associated with transcriptional silencing was observed only in 4 cases. Since partial methylation could not silence the transcription, and the tax gene transcription was not detected in 27 of 41 cases (66%), the epigenetic change(s) other than DNA methylation is considered to play an important role in the silencing. © 2004 Wiley‐Liss, Inc.
Reduction of TSG101 protein has a negative impact on tumor cell growth
Authors: Zhu Gang , Gilchrist Ruth , Borley Nigel , Chng Hsiao Wee , Morgan Mark , Marshall John F. , Camplejohn Richard S. , Muir Gordon H. , Hart Ian R.
Published: February 2004

TSG101 was defined originally as a tumor‐suppressor gene, raising the expectation that absence of the encoded protein should lead to increased tumor cell growth and, perhaps, increased tumor cell aggressiveness. We have used the RNA interference (RNAi) technique to downregulate TSG101 in PC3 (prostate cancer) and MDA‐MB‐231 (breast cancer) cells. An approximately 85% selective downregulation at the protein level was achieved in both cell lines over a period of 12 days as detected by Western blotting. This treatment resulted in inhibition of tumor cell growth, with a decreased level of TSG101 causing partial cell cycle arrest at the G1/S boundary and a reduction in the rate at which cells passed from G2 through mitosis and back into G1. In both cell lines, the percentage of cells in S‐phase was reduced significantly at day 4 after the TSG101 siRNA transfection (27% vs. 41% in MDA‐MB‐231 cells; 22% vs. 39% in PC3 cells). Additionally, RNAi‐mediated downregulation of TSG101 reduced the colony formation capacities of both cancer cell lines. Rather more surprisingly, TSG101 downregulation affected the migratory activity of the MDA‐MB‐231 cells, independent of any effect on proliferation. Thus, in a Transwell assay, after 4‐hr incubation, 36.0% of control MDA‐MB‐231 cells had migrated to the lower chamber vs. 7.3% of TSG101‐downregulated cells (p < 0.001; scrambled control, 36.5%). These results show that the TSG101 gene does not comply with the usual characteristics of a tumor‐suppressor gene; rather, its expression may be necessary for activities associated with aspects of tumor progression. © 2004 Wiley‐Liss, Inc.
Oxytocin inhibits the progression of human ovarian carcinoma cells in vitro and in vivo
Authors: Morita Takanori , Shibata Kiyosumi , Kikkawa Fumitaka , Kajiyama Hiroaki , Ino Kazuhiko , Mizutani Shigehiko
Published: February 2004

The neurohypophyseal nonapeptide oxytocin (OT) is involved in many biologic functions and regulation of cell proliferation under both physiologic and neoplastic conditions. In some cases, OT exhibits an oxytocin receptor (OTR)‐mediated antiproliferative effect on cancer cells. In this study, we examined the effects of OT on ovarian carcinoma progression in vitro and in vivo. We investigated the inhibitory effects of OT on cell growth, invasion and migration in vitro. Furthermore, we examined the OT effects in vivo ovarian carcinoma model. We demonstrated OTR expressions in the large majority of ovarian carcinoma tissues, and OT inhibited not only proliferation but also migration and invasion in ovarian carcinoma cells in vitro. Furthermore, we examined the mechanisms of the antiinvasive ability of OT. Secretion of matrix metalloproteinase 2 was slightly inhibited by 10−7 M OT, while treatment with 10−7 M OT for 24 hr remarkably enhanced the expression of E‐cadherin. In addition, our in vivo study showed that intraperitoneal administration of OT resulted in the reduction of intraperitoneal dissemination of ovarian carcinoma cells. Mean tumor burden in the OT‐treated group (0.2 ± 0.11 g) was significantly (p < 0.05) less than that of physiologic saline‐treated group (0.5 ± 0.54 g). This evidence implies that OT may functionally suppress peritoneal dissemination in ovarian carcinoma. © 2004 Wiley‐Liss, Inc.
Lung cancer mortality patterns in selected Central, Eastern and Southern European countries
Authors: Tyczynski Jerzy E. , Bray Freddie , Aareleid Tiiu , Dalmas Miriam , Kurtinaitis Juozas , Plesko Ivan , Pompe‐Kirn Vera , Stengrevics Aivars , Parkin D. Maxwell
Published: February 2004

Significant changes in the prevalence of tobacco smoking have been observed in many European countries. EU candidate countries have also experienced major changes with respect to tobacco smoking, which have resulted in changes in the frequency of lung cancer. In men in the majority of these countries, a reduction of mortality rates has been observed recently, while in Hungary and Poland a deceleration of mortality increase was observed in the 1990s. The situation is much less favorable in females, where in the majority of countries a continuous increase of mortality rates has been observed, the only exceptions being Latvia, Lithuania and, to a lesser extent, Estonia. In Hungarian women, an acceleration of the increase rate was observed in the 1980s and 1990s (compared with the 1970s). Patterns of lung cancer mortality in analyzed countries are somewhat similar to those observed in EU member states. Recent analyses of time trends of lung cancer in EU countries showed, in general, a decreasing risk in the majority of male populations and an increase in several countries in women. If the decrease of mortality is to be achieved and maintained in the longer term, efforts have to be focused on young generations (entering adulthood now or in the near future). Despite all the difficulties present in reducing tobacco smoking in youth, it seems that one of the most important ways to reduce the future lung cancer burden in current and new EU member states is to strengthen efforts toward changing smoking attitudes in young generations. © 2004 Wiley‐Liss, Inc.
Comprehensive analysis of the contribution of germline MYH variation to early‐onset colorectal cancer
Authors: Fleischmann Christina , Peto Julian , Cheadle Jeremy , Shah Bindiya , Sampson Julian , Houlston Richard S.
Published: February 2004

Mutations in the base excision repair gene MYH have recently been shown to confer recessive susceptibility to colorectal adenomas and carcinomas. To evaluate the contribution of germline MYH mutations to early‐onset colorectal cancer, we screened a series of 358 unselected early‐onset cases for germline changes in the coding sequence of the gene. Two cases harbored biallelic germline mutations (0.6%; 95% CI = 0.06–2.0) and 8 single MYH mutations (2.2%; 95% CI = 0.9–4.4). Both cases harboring biallelic MYH mutations had multiple polyps but not profuse polyposis. All cases had distally sited tumors. No biallelic mutations were detected among 354 controls. These results confirm that biallelic MYH mutations confer susceptibility to colorectal cancer but are unlikely to account for more than 3% of early‐onset colorectal cancer. © 2004 Wiley‐Liss, Inc.
Evaluation of systemic chemotherapy with magnetic liposomal doxorubicin and a dipole external electromagnet
Authors: Nobuto Hiroo , Sugita Takashi , Kubo Tadahiko , Shimose Shoji , Yasunaga Yuji , Murakami Teruo , Ochi Mitsuo
Published: February 2004

The development of an active drug delivery system is an attractive approach to increase the targetability of anticancer agents. In the present study, we examined the efficiency of systemic chemotherapy with small magnetic liposomes containing doxorubicin (magnetic DOX liposomes) and an externally applied electromagnetic force in osteosarcoma‐bearing hamsters. Syrian male hamsters inoculated with osteosarcoma, OS515, in the limb were studied 7 days after inoculation. The efficiency of this system was evaluated by measuring the tissue distribution and tumor‐suppressing effects of DOX on primary tumor growth and lung metastases. A DC dipole electromagnet was used, and the hamster's tumor‐bearing limb was placed between 2 poles after the i.v. administration of liposomes. The dose of DOX and the magnetic field strength were fixed at 5 mg/kg and 0.4 T, respectively. Administration of magnetic DOX liposomes followed by 60 min application of magnetic field produced a 3‐ to 4‐fold higher maximum DOX concentration in the tumor. This newly designed systemic chemotherapy significantly suppressed primary tumor growth for at least 2 weeks, though other DOX treatments also suppressed compared to control. Histologic examination confirmed a greater antitumor effect of this systemic chemotherapy compared to standard methods. In addition, this approach significantly suppressed lung metastases measured at 3 weeks posttreatment. These results suggest that this systemic chemotherapy can effectively reduce primary tumor growth and suppress lung metastasis due to increased targeting of DOX. Such targeted drug delivery for anticancer agents would provide clinical advantages compared to current methods. © 2004 Wiley‐Liss, Inc.
Analysis of bending behavior of native and engineered auricular and costal cartilage
Authors: Roy Rani , Kohles Sean S. , Zaporojan Victor , Peretti Giuseppe M. , Randolph Mark A. , Xu Jianwei , Bonassar Lawrence J.
Published: February 2004

A large‐deflection elasticity model was used to describe the mechanical behavior of cartilaginous tissues during three‐point bending tests. Force‐deflection curves were measured for 20‐mm long × 4‐mm wide × ≈1‐mm thick strips of porcine auricular and costal cartilage. Using a least‐squares method with elastic modulus in bending as the only adjustable parameter, data were fit to a model based on the von Karman theory for large deflection of plates. This model described the data well, with an average RMS error of 14.8% and an averageR2value of 0.98. Using this method, the bending modulus of auricular cartilage (4.6 MPa) was found to be statistically lower (p< 0.05) than that of costal cartilage (7.1 MPa). Material features of the cartilage samples influenced the mechanical behavior, including the orientation of the perichondrium in auricular cartilage. These methods also were used to determine the elastic moduli of engineered cartilage samples produced by seeding chondrocytes into fibrin glue. The modulus of tissue‐engineered constructs increased statistically with time (p< 0.05), but still were statistically lower than the moduli of the native tissue samples (p> 0.05), reaching only about a third of the values of native samples. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 597–602, 2004
Cell seeding into calcium phosphate cement
Authors: Simon Carl G. , Guthrie William F. , Wang Francis W.
Published: February 2004

To improve the effectiveness of calcium phosphate cement (CPC), we have developed a method to seed osteoblasts into the cement. CPC powder is mixed with water to form a paste that can be shaped to fit a bone defectin situ. The paste hardens in 30 min, reacts to form hydroxyapatite, and is replaced with new bone. Reacted CPC is biocompatible but unreacted CPC paste was found to have toxic effects when placed on cell monolayers (MC3T3‐E1 cells). In contrast, when cells were indirectly exposed to CPC paste using a porous membrane or by placing a coverslip containing adherent cells onto a bed of CPC paste, the unreacted CPC was nontoxic. These results suggested that gel encapsulation of the cells might protect them from the CPC paste. Thus, cells were encapsulated in alginate beads (3.6‐mm diameter), mixed with CPC paste, and incubated overnight. Both vital staining (calcein‐AM and ethidium homodimer‐1) and the Wst‐1 assay (measures dehydrogenase activity) showed that cell survival in alginate beads that were mixed with CPC was similar to survival in untreated control beads. These results suggest that gel encapsulation could be used as a mechanism to protect cells for seeding into CPC. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 628–639, 2004
Vascularization of PEG‐grafted macroporous hydrogel sponges: A three‐dimensional in vitro angiogenesis model using human microvascular endothelial cells
Authors: Dziubla T. D. , Lowman A. M.
Published: February 2004

Vascular tissue can penetrate implants that have an interconnected porous structure. The extent of vascularization is heavily dependent on a number of factors, including the nature of the material as well as the size and porosity of the implant's pore morphology. Currently, it is still not clear what mechanisms are controlling this response. In this work, in vitro human microvascular endothelial cell (HMVEC) experiments employed in angiogenesis research have been adapted as a screening technique for biomaterial vascularization. Hydrogels composed of poly(2‐hydroxy ethyl methacrylate) (PHEMA) containing poly(ethylene glycol) (PEG) grafts were capable of supporting in vitro tubule formation. The sizes and lengths of tubules were dependent upon the porosity of the polymer network and pore sizes. When compared to the pure PHEMA sponges, PEG‐grafted networks possessed a more lattice‐type structure, with greater pore interconnection. As a result, these polymers were better suited to supporting tubule formation. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 603–614, 2004
Model surfaces engineered with nanoscale roughness and RGD tripeptides promote osteoblast activity
Authors: El‐Ghannam A. R. , Ducheyne P. , Risbud M. , Adams C. S. , Shapiro I. M. , Castner D. , Golledge S. , Composto R. J.
Published: February 2004

Cell adhesion to biomaterials is a prerequisite for tissue integration with the implant surface. Herein, we show that we can generate a model silica surface that contains a minimal‐length arginine‐glycine‐aspartic acid (RGD) peptide that maintains its biological activity. In the first part of this study, attachment of MC3T3‐E1 osteoblast‐like cells was investigated on silicon oxide, amine terminated substrates [i.e., 3‐aminopropyl triethoxysilane (APTS)], grafted RGD, and physisorbed RGD control. The APTS layer exhibited nanoscale roughness and presented amine functional groups for grafting a minimal RGD tripeptide devoid of any flanking groups or spacers. Contact angle measurements indicated that the hydrophobicity of the APTS surface was significantly lower than that of the surface with grafted RGD (RGD–APTS). Atomic force microscopy showed that surfaces covered with RGD–APTS were smoother (Ra = 0.71 nm) than those covered with APTS alone (Ra = 1.59 nm). Focusing mainly on cell morphology, experiments showed that the RGD–APTS hybrid provided an optimum surface for cell adhesion, spreading, and cytoskeletal organization. Discrete focal adhesion plaques were also observed consistent with successful cell signaling events. In a second set of experiments, smooth, monolayers of APTS (Ra = 0.1 nm) were used to prepare arginine‐glycine‐aspartic acid‐serine (RGDS)–APTS and arginine‐glycine‐glutamic acid‐serine (RGES)–APTS (control) substrates. Focusing mainly on cell function, integrin and gene expression were all enhanced for rate osteosarcoma cells on surfaces containing grafted RGDS. Both sets of studies demonstrated that grafted molecules of RGD(S) enhance both osteoblast‐like cell adhesion and function. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 615–627, 2004
Effect of excipient composition on the biocompatibility of bupivacaine‐containing microparticles at the sciatic nerve
Authors: Colombo Gaia , Langer Robert , Kohane Daniel S.
Published: February 2004

Microparticulate formulations are often used for experimental prolongation of nerve blockade. Here we examine the effect of excipient composition on the biocompatibility of bupivacaine‐containing microparticles. Lipid–protein–sugar particles (LPSPs) composed of 3% (1.3‐μm diameter) and 60% (4.7‐μm diameter) (w/w) dipalmitoylphosphatidylcholine (DPPC) were produced by spray drying, containing 10% (w/w) bupivacaine. Rat sciatic nerve blocks with 75 mg of particles produced statistically similar durations of sensory nerve block [3% (w/w) DPPC particles: 301 min; 60% (w/w) DPPC particles: 321 min]. Examination of tissues 1 day after injection revealed large particle deposits and acute inflammation in animals that received 60% (w/w) DPPC particles. There were no visible deposits in those that received 3% (w/w) DPPC particles, and microscopic inflammation was reduced. The difference between groups was similar 4 days after injection. Two weeks after injection, there was no particulate mass in either group, and inflammation had largely resolved. In both groups, moderately severe myotoxicity was seen 1 and 4 days after injection but had largely resolved by 2 weeks. In summary, reduction in particles' DPPC content greatly improved biocompatibility without compromising duration of nerve blockade; the improvement was probably attributable to the enhanced rate of particle resorption. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 651–659, 2004
Osteoblast attachment and mineralized nodule formation on rough and smooth 45S5 bioactive glass monoliths
Authors: Gough J.E. , Notingher I. , Hench L.L.
Published: February 2004

Human primary osteoblast responses to smooth and roughened bioactive glass of 45S5 (Bioglass™) composition (46.1% SiO2, 26.9% CaO, 2.6% P2O5, 24.4% Na2O) were analysed in vitro. The smooth and rough surfaces had Ra values and peak to valley distances of 0.04, 4.397, 2.027, and 21.328 μm, respectively. Cell attachment and morphology was observed using phalloidin staining of the actin cytoskeleton and revealed significant differences between smooth and rough surfaces. Cells that were spiky in appearance on the rough compared to the smooth surface formed an organized actin matrix much later on the rough surface. Scanning electron microscopy revealed many cell filipodia extending from more rounded cell bodies on the rough surface. A significantly greater number of nodules on the rough surface was observed, and these were shown to mineralize when supplemented with beta‐glycerophosphate and dexamethasone. Raman spectroscopy confirmed the presence of hydroxyapatite in the mineralized cultures showing a definite peak at 964 cm−1. FTIR analysis showed hydroxyapatite formation occurred more rapidly on the rough surface. This study demonstrates that although initial cell morphology was less advanced on the roughened surface, the cells were able to form mineralized nodules in greater numbers. This may have implications to bone tissue engineering using bioactive glasses. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 640–650, 2004
Patterning adhesion of mammalian cells with visible light, tris(bipyridyl)ruthenium(II) chloride, and a digital micromirror array
Authors: Luebke Kevin J. , Carter Duane E. , Garner Harold R. , Brown Kathlynn C.
Published: February 2004

Patterns of cellular adhesion were created on a surface using novel photochemistry that is stimulated with visible light. A glass surface coated with polyethylene glycol is nonadhesive to a variety of adherent mammalian cell types. Treatment of that surface with a mixture of tris(bipyridyl)ruthenium(II) chloride, ammonium persulfate, and a tryptophan derivative or tryptophan‐bearing peptide in conjunction with irradiation with visible light (447 nm) made the surface adhesive to several cell types including mouse fibroblasts, human myoblasts, and human lung tumor cells. Immunostaining data suggest that tryptophan‐containing peptides are crosslinked intact to the surface by this chemistry, which enables patterning of peptides containing only naturally occurring amino acids. Microscopic patterns of cellular adhesion were created with this chemistry by projecting microscopic patterns of visible light with a digital micromirror array. Using this method, regions of cellular adhesion were patterned with single‐cell resolution. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 696–703, 2004
MMP‐2 sensitive, VEGF‐bearing bioactive hydrogels for promotion of vascular healing
Authors: Seliktar D. , Zisch A. H. , Lutolf M. P. , Wrana J. L. , Hubbell J. A.
Published: February 2004

We sought to develop bioactive hydrogels to facilitate arterial healing, e.g., after balloon angioplasty. Toward this end, we developed a new class of proteolytically sensitive, biologically active polyethylene glycol (PEG)‐peptide hydrogels that can be formed in situ to temporarily protect the arterial injury from blood contact. Furthermore, we incorporated endothelial cell‐specific biological signals with the goal of enhancing arterial reendothelialization. Here we demonstrate efficient endothelial cell anchorage and activation on PEG hydrogel matrices modified by conjugation with both the cell adhesive peptide motif RGD and an engineered variant of vascular endothelial growth factor (VEGF). By crosslinking peptide sequences for cleavage by MMP‐2 into the polymer backbone, the hydrogels became sensitive to proteolytic degradation by cell‐derived matrix metalloproteinases (MMPs). Analysis of molecular hallmarks associated with endothelial cell activation by VEGF‐RGD hydrogel matrices revealed a 70% increase in production of the latent MMP‐2 zymogen compared with PEG‐peptide hydrogels lacking VEGF. By additional provision of transforming growth factor β1 (TGF‐β1) within the PEG‐peptide hydrogel, conversion of the latent MMP zymogen into its active form was demonstrated. As a result of MMP‐2 activation, strongly enhanced hydrogel degradation by activated endothelial cells was observed. Our data illustrate the critical importance of growth factor activities for remodeling of synthetic biomaterials into native tissue, as it is desired in many applications of regenerative medicine. Functionalized PEG‐peptide hydrogels could help restore the native vessel wall and improve the performance of angioplasty procedures. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 704–716, 2004
In vitro biocorrosion of Ti‐6Al‐4V implant alloy by a mouse macrophage cell line
Authors: Lin Hsin‐Yi , Bumgardner Joel D.
Published: February 2004

Corrosion of implant alloys releasing metal ions has the potential to cause adverse tissue reactions and implant failure. We hypothesized that macrophage cells and their released reactive chemical species (RCS) affect the alloy's corrosion properties. A custom cell culture corrosion box was used to evaluate how cell culture medium, macrophage cells and RCS altered the Ti‐6Al‐4V corrosion behaviors in 72 h and how corrosion products affected the cells. There was no difference in the charge transfer in the presence (75.2 ± 17.7 mC) and absence (62.3 ± 18.8 mC) of cells. The alloy had the lowest charge transfer (28.2 ± 4.1 mC) and metal ion release (Ti < 10 ppb, V < 2 ppb) with activated cells (releasing RCS) compared with the other two conditions. This was attributed to an enhancement of the surface oxides by RCS. Metal ion release was very low (Ti < 20 ppb, V < 10 ppb) with nonactivated cells and did not change cell morphology, viability, and NO and ATP release compared with controls. However, IL‐1β released from the activated cells and the proliferation of nonactivated cells were greater on the alloy than the controls. In summary, macrophage cells and RCS reduced the corrosion of Ti‐6Al‐4V alloys as hypothesized. These data are important in understanding host tissue‐material interactions. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 717–724, 2004
Fast‐setting calcium phosphate scaffolds with tailored macropore formation rates for bone regeneration
Authors: Xu Hockin H. K. , Takagi Shozo , Quinn Janet B. , Chow Laurence C.
Published: February 2004

Calcium phosphate cement (CPC) is highly promising for craniofacial and orthopedic repair because of its ability to self‐harden in situ to form hydroxyapatite with excellent osteoconductivity. However, its low strength, long hardening time, and lack of macroporosity limit its use. This study aimed to develop fast‐setting and antiwashout CPC scaffolds with high strength and tailored macropore formation rates. Chitosan, sodium phosphate, and hydroxypropyl methylcellulose (HPMC) were used to render CPC fast‐setting and resistant to washout. Absorbable fibers and mannitol porogen were incorporated into CPC for strength and macropores for bone ingrowth. Flexural strength, work‐of‐fracture, and elastic modulus were measured vs. immersion time in a physiological solution. Hardening time (mean ± SD; n = 6) was 69.5 ± 2.1 min for CPC‐control, 9.3 ± 2.8 min for CPC‐HPMC‐mannitol, 8.2 ± 1.5 min for CPC‐chitosan‐mannitol, and 6.7 ± 1.6 min for CPC‐chitosan‐mannitol‐fiber. The latter three compositions were resistant to washout, whereas the CPC‐control paste showed washout in a physiological solution. Immersion for 1 day dissolved mannitol and created macropores in CPC. CPC‐chitosan‐mannitol‐fiber scaffold had a strength of 4.6 ± 1.4 MPa, significantly higher than 1.2 ± 0.1 MPa of CPC‐chitosan‐mannitol scaffold and 0.3 ± 0.2 MPa of CPC‐HPMC‐mannitol scaffold (Tukey's). The strength of CPC‐chitosan‐mannitol‐fiber scaffold was maintained up to 42 days and then decreased because of fiber degradation. Work‐of‐fracture and elastic modulus showed similar trends. Long cylindrical macropore channels were formed in CPC after fiber dissolution. The resorbable, fast‐setting, anti‐washout and strong CPC scaffold should be useful in craniofacial and orthopedic repairs. The novel method of combining fast‐ and slow‐dissolution porogens/fibers to produce scaffolds with high strength and tailored macropore formation rates to match bone healing rates may have wide applicability to other biomaterials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 725–734, 2004
Crosslinking of collagen gels by transglutaminase
Authors: Orban Janine M. , Wilson Lorri B. , Kofroth Jessica A. , El‐Kurdi Mohammed S. , Maul Timothy M. , Vorp David A.
Published: February 2004

Collagen is commonly used as a tissue‐engineering scaffold, yet its in vivo applications are limited by a deficiency in mechanical strength. The purpose of this work was to explore the utilization of a unique enzymatic crosslinking procedure aimed at improving the mechanical properties of collagen‐based scaffold materials. Type I bovine collagen gel was crosslinked by transglutaminase, which selectively mediates the chemical reaction between glutamine and lysine residues on adjacent protein fibers, thus providing covalent amide bonds that serve to reinforce the three‐dimensional matrix. The degree of crosslinking was verified by thermal analysis and amine group content. The denaturation temperature of crosslinked collagen reached a maximum of 66 ± 1°C. The chemical reaction was confirmed to be noncytotoxic with respect to bone marrow stromal cells acquired from New Zealand White rabbits. Tube‐shaped cellular constructs fashioned from crosslinked collagen and bone marrow stromal cells were found to have burst pressures significantly higher than their noncrosslinked analogs (71 ± 4 mmHg vs. 46 ± 3 mmHg; p < 0.01). Thus, the transglutaminase mediated reaction served to successfully strengthen collagen gels while remaining benign toward cells. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 756–762, 2004
Effect of chemical structure and composition of the resin phase on mechanical strength and vinyl conversion of amorphous calcium phosphate‐based composites
Authors: Skrtic D. , Antonucci J.M. , McDonough W.G. , Liu D.W.
Published: February 2004

The mechanical properties of recently developed bioactive, antidemineralizing/remineralizing, amorphous calcium phosphate (ACP)‐based composites need improvement. The objective of this study was to elucidate the effect of structure and composition of resins on the biaxial flexure strength (BFS) and the degree of conversion (DC) of composites attained after photo‐polymerization. Two series of 2,2‐bis[p‐(2′‐hydroxy‐3′‐methacryloxypropoxy)phenyl]propane (Bis‐GMA)/triethylene glycol dimethacrylate (TEGDMA)/X (X being a neutral or acidic comonomer) ternary resins were prepared and mixed with a mass fraction of 40% of zirconia‐hybridized ACP. Both unfilled copolymers and their composites were evaluated for BFS (dry and wet specimens after 2 weeks of immersion in buffered saline) and for DC (after 24 h at 23°C). It was found that for the neutral X monomers, no correlation existed between the hydrophobic/hydrophilic character of the X monomer and the BFS values of the immersed composites. A flexible monomethacrylate yielded copolymers and composites with the highest DC. For the resins utilizing the acidic comonomers, methacrylic acid and mono‐4‐(methacryloyloxy) ethyltrimellitate (4MET), dry composites with improved BFS values were obtained. 4MET composites exhibited the least loss of strength of all the ternary resin ACP materials. The effect of acidic X on DC was most pronounced for maleic acid copolymers. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 763–772, 2004
In vitro osteogenic differentiation of human mesenchymal stem cells photoencapsulated in PEG hydrogels
Authors: Nuttelman Charles R. , Tripodi Margaret C. , Anseth Kristi S.
Published: February 2004

Much research has focused on the differentiation of human mesenchymal stem cells (hMSCs) in monolayer culture; however, little is known about their differentiation potential in three‐dimensional culture conditions. In this research, hMSCs were encapsulated in a photocrosslinkable, injectable scaffolding system based on poly(ethylene glycol) (PEG) hydrogels. To demonstrate the ability of hMSCs to differentiate in PEG hydrogels, cell/polymer constructs were cultured in osteogenic differentiation media to elicit an osteoblastic response. First, viability of encapsulated hMSCs up to 4 weeks in culture was investigated using a membrane integrity assay. Second, gene expression of encapsulated cells was determined with reverse transcription polymerase chain reaction (RT‐PCR) as a function of media composition. After 1 week in osteogenic differentiation media, encapsulated hMSCs expressed osteonectin, osteopontin, and alkaline phosphatase, which are all characteristic of osteoblasts. Finally, von Kossa staining was used to evaluate mineralization of the PEG gels. Results support the hypothesis that hMSCs photoencapsulated in PEG hydrogels and cultured in the presence of osteogenic differentiation media are able to differentiate to osteoblasts inside the gel and mineralize the matrix. These experiments demonstrate the feasibility of using a PEG‐based, photocrosslinkable system to culture and deliver human mesenchymal stem cells for bone tissue regeneration and repair. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 773–782, 2004
Endotoxin increases hepatic susceptibility to lipid peroxidation: A possible role of iron
Authors: Ibrahim W. , Lee U.‐S. , Chow C. K.
Published: February 2004

The purpose of this study was to investigate the possible mechanism by which endotoxin enhances peroxidative damage to membrane lipids. Male B6C3 mice were treated with endotoxin intraperitoneally 0 or 20 mg/kg body weight for 24 h. Freshly prepared liver homogenate was incubated with either 1–5 mM of reduced glutathione (GSH), glucose, H2O2, ascorbic acid (AA), FeSO4, FeCl3, EDTA, FeCl3 plus AA, AA plus EDTA or EDTA plus FeCl3 in phosphate‐buffered saline (PBS), pH 7.0, or PBS, at 37°C for 60 min. The levels of lipid peroxidation products, thiobarbituric acid reactants (TBAR), were significantly higher in the liver of endotoxin‐treated mice, and the values were markedly increased following incubation. Compared to PBS, incubation with H2O2, FeCl3, FeSO4, and AA, but not glucose, significantly enhanced TBAR formation. The greatest increase of TBAR was found when AA and FeCl3 were added together. On the other hand, EDTA and GSH inhibited the formation of TBAR during incubation. When added before AA, EDTA completely inhibited the peroxidative effect of AA or FeSO4, and when added subsequent to AA, EDTA partially prevented the adverse effect of AA. The results obtained suggest that ionic iron plays an important role in initiating endotoxin‐induced peroxidative damage to membrane lipids, and that AA may be involved in releasing iron from its protein complex and/or maintaining ionic iron in a reduced or catalytic state. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:23–29, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20002
BMP7/ActRIIB regulates estrogen‐dependent apoptosis: New biomarkers for environmental estrogens
Authors: Kusumegi Takahiro , Tanaka Junko , Kawano Michihiro , Yonemoto Junzo , Tohyama Chiharu , Sone Hideko
Published: February 2004

A ligand‐receptor pair, bone morphogenetic protein‐7 (BMP7) and activin receptor IIB (actRIIB), was identified from a pool of DNA fragments recovered from MCF7 cells treated with 17β‐estradiol (E2) by chromatin immunoprecipitation with antiestrogen receptor‐αantibody. The E2 responsiveness of both genes was confirmed in MCF cells and in the mouse uterus. Repeated treatment with E2 resulted in decreased expression of both actRIIB and BMP7 mRNA in the uteri of ovariectomized mice. A single oral administration of bisphenol A (BPA), an environmental estrogen, inhibited actRIIB and BMP7 expression and apoptosis in the luminal epithelium of the mouse uterus at diestrus (or early proestrus). This decrease, due to BPA administration, was restored by an estrogen receptor (ER) antagonist suggesting that it is mediated through ERs. These results suggest that E2 and BPA suppress estrogen‐dependent apoptosis of epithelial cells of the endometrium through down‐regulation of actRIIB and BMP7. Thus, we propose that BMP7 and actRIIB, a ligand‐receptor pair, are involved in regulation of the apoptotic signaling pathway and might therefore be new biomarkers of the effects of environmental estrogens on the female reproductive tract. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:1–11, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20004
New insights into the mechanisms involved in renal proximal tubular damage induced in vitro by ochratoxin A
Authors: Gennari Alessandra , Pazos Patricia , Boveri Monica , Callaghan Robert , Casado Juan , Maurici Daniela , Corsini Emanuela , Prieto Pilar
Published: February 2004

The mycotoxin ochratoxin A is a contaminant of human and animal food products. It is a potent nephrotoxin known to damage the proximal tubule. The aim of this work was to investigate the effects of ochratoxin A on a porcine renal proximal tubular epithelial cell line (LLC‐PK1), and to identify sensitive endpoints revealing damage at the epithelial barrier level and at the molecular level. Cells exposed for 24 h to 5–10 μM ochratoxin indicated a clear damage to the intactness of the epithelial barrier, as shown by measurements of trans‐epithelial resistance and zonula occludens‐1 protein expression. At the mitochondrial level we observed alterations of the normal functions, such as an increase of the membrane potential, the formation of straight extensions, and the formation of giant mitochondria. At higher ochratoxin concentrations (50 μM), at which cytotoxicity assays revealed a significant toxicity, alterations of the cytoskeleton organization and induction of apoptosis were evident. In addition, we analyzed the expression of genes by using a cDNA macroarray. Our data indicate that ochratoxin‐induced nephrotoxicity can be detected at the barrier and at the mitochondrial level at rather low concentrations, at which conventional cytotoxicity assays are unable to reveal toxic effects. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:43–49, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20006
Generation of an oxidative stress precedes caspase activation during 7β‐hydroxycholesterol‐induced apoptosis in U937 cells
Authors: Ryan Lisa , O'Callaghan Yvonne C. , O'Brien Nora M.
Published: February 2004

The oxysterol 7beta‐hydroxycholesterol (7β‐OH) has been shown to induce apoptosis in a number of cell lines. Though not fully elucidated, the mechanism through which this oxysterol induces cell death is thought to involve the generation of an oxidative stress leading to perturbation of the mitochondrion and release of cytochrome c into the cytosol. Cytochrome c together with Apaf‐1 causes activation of the initiator caspase, caspase‐9, which in turn activates caspase‐3 ultimately leading to the degradation of poly(ADP‐ribose) polymerase (PARP). The objective of the present study was to investigate the signalling pathway in 7β‐OH‐induced apoptosis in U937 cells, a human monocytic blood cell line known to undergo apoptosis upon treatment with 7β‐OH, over a time course of 48 h. Apoptosis was evident after 24 h incubation. Glutathione levels were decreased after 6 h and this was coupled with an increase in SOD activity. Through western blot analysis we examined expression of caspase‐3, ‐8, and ‐9 and cleavage of the caspase‐3 substrate PARP. The sequence proceeded with activation of caspase‐9 after 9 h, caspase‐3 at the 12 h timepoint, and cleavage of PARP after 24 h treatment with 7β‐OH. Caspase‐8 did not appear to play a major role in this particular apoptotic pathway. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:50–59, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20007
Need cash? Don't forget leveraged recaps
Authors: Hooke Jeff
Published: February 2004

Leveraged recapitalizations are viable alternatives for entrepreneurial firms and family businesses that are
shut off from reasonable pricing in the IPO and M&A markets. Recaps are also useful tools for large
corporations—especially when they need cash from a division but want to retain a portion of the
division's operating upside. © 2004 Wiley Periodicals, Inc.
Activity‐based planning and budgeting: The coming of age of the “consumption‐based” approach
Authors: Stevens Mark E.
Published: February 2004

The financial performance of an organization is driven by the demand for its products and services and the
consumption of the activities and resources required to provide them. © 2004 Wiley Periodicals,
Inc.
Using ABC to manage and improve at CONCO foods
Authors: Schulist Stephen
Published: February 2004

Activity‐based costing (ABC) is a journey not a destination. It has evolved from its beginnings
into an ongoing process that is more aptly called profitability management. Profitability
management is the process of using information from an ABC software tool to continually manage and improve the
business. © 2004 Wiley Periodicals, Inc.
Prostate cancer bone metastases promote both osteolytic and osteoblastic activity
Authors: Keller Evan T. , Brown Julie
Published: February 2004

Advanced prostate cancer is frequently accompanied by the development of metastasis to bone. In the past, prostate cancer bone metastases were characterized as being osteoblastic (i.e., increasing bone density) based on radiographs. However, emerging evidence suggests that development of prostate cancer bone metastases requires osteoclastic activity in addition to osteoblastic activity. The complexities of how prostate tumor cells influence bone remodeling are just beginning to be elucidated. Prostate cancer cells produce a variety of pro‐osteoblastic factors that promote bone mineralization. For example, both bone morphogenetic proteins and endothelin‐1 have well recognized pro‐osteoblastic activities and are produced by prostate cancer cells. In addition to factors that enhance bone mineralization prostate cancer cells produced factors that promote osteoclast activity. Perhaps the most critical pro‐osteoclastogenic factor produced by prostate cancer cells is receptor activator of NFκB ligand (RANKL), which has been shown to be required for the development of osteoclasts. Blocking RANKL results in inhibiting prostate cancer‐induced osteoclastogenesis and inhibits development and progression of prostate tumor growth in bone. These findings suggest that targeting osteoclast activity may be of therapeutic benefit. However, it remains to be defined how prostate cancer cells synchronize the combination of osteoclastic and osteoblastic activity. We propose that as the bone microenvironment is changed by the developing cancer, this in turn influences the prostate cancer cells' balance between pro‐osteoclastic and pro‐osteoblastic activity. Accordingly, the determination of how the prostate cancer cells and bone microenvironment crosstalk are important to elucidate how prostate cancer cells modulate bone remodeling. © 2003 Wiley‐Liss, Inc.
Modulation of prostate cancer growth in bone microenvironments
Authors: Edlund Magnus , Sung Shian‐Ying , Chung Leland W.K.
Published: February 2004

Bone remains one of the major sites, and most lethal host organs, for prostate cancer metastasis. Prostate cell spread and establishment in bone depends on multiple reciprocal modifications of bone stromal and epithelial cancer cell behaviors. This review focuses on recent advances in the characterization of cell–cell and cell–matrix interplay, effects on cell growth, adhesion and invasion, and several therapeutic possibilities for co‐targeting prostate cancer cells and bone stroma. We address the topic from three main perspectives: (1) the normal and aging bone stromal environment, (2) the “reactive” bone stromal environment, and (3) the cancerous prostate epithelial cells themselves. First, normal, and especially aging, bones provide uniquely rich and “fertile soil” for roaming cancer cells. The interactions between prostate cancer cells and insoluble extracellular matrices, soluble growth factors, and/or sex steroid hormones trigger bone remodeling, through increased osteoclastogenesis and furthur matrix metalloproteinase activity. Second, after cancer cell arrival and establishment in the bone, host stromal cells respond, becoming “reactive” in a process again involving extracellular matrix remodeling, together with growth factor and steroid receptor signaling this process ultimately enhances cancer cell migration, stromal transdifferentiation, and invasion of the cancer tissues by stromal, inflammatory, and immune‐responsive cells. Third, prostate cancer cells also respond to supportive bone microenvironments, where soluble and matrix‐associated molecules affect cancer cell growth and gene expression, especially altering cancer cell surface receptor and integrin‐mediated cell signaling. We discuss both integrin cell–matrix and gap junctional cell–cell communication between cancer cells and their microenvironments during prostate cancer progression. © 2003 Wiley‐Liss, Inc.