bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation and drug release property of star poly(ϵ‐caprolactone)s with dendritic cores
Authors: Miao Zhi‐Mei , Cheng Si‐Xue , Zhang Xian‐Zheng , Wang Qing‐Rong , Zhuo Ren‐Xi 
Published: August 2006

AbstractA series of star poly(ϵ‐caprolactone)s (PCL) with dendritic cores, PAMAM‐PCLs, were synthesized through the ring‐opening polymerization of ϵ‐caprolactone (CL) initiated by poly(amidoamine) dendrimer (PAMAM‐OH). By controlling the feed ratio of the macroinitiator PAMAM‐OH to the monomer CL, the star polymers with different branch lengths and properties can be obtained. The successful incorporation of PCL sequences onto the PAMAM‐OH core was verified by FTIR, 1H NMR, and combined size‐exclusion chromatography and multiangle laser light scattering analysis. The in vitro degradation of PAMAM‐PCLs was investigated. The results show the hydrolytic degradation rate increases with increasing content of hydrophilic PAMAM‐OH core. While the enzymatic degradation rate is affected by two competitive factors, the catalytic effect of Pseudomonas cepacia lipase on the degradation of PCL branches and the hydrophilicity that depends on the polymer composition. Using the PAMAM‐PCLs with different molecular weights, the microsphere drug delivery systems with submicron sizes were fabricated using an “ultrasonic assisted precipitation method.” The in vitro drug release from these microspheres was investigated. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Confocal laser scanning microscopy using dialkylcarbocyanine dyes for cell tracing in hard and soft biomaterials
Authors: Heinrich Laurence , Freyria Anne‐Marie , Melin Martine , Tourneur Yves , Maksoud Rami , Bernengo Jean‐Claude , Hartmann Daniel Jean 
Published: August 2006

AbstractThe aim of this work was to study, in vitro, cell colonization of two biomaterials currently used for bone and cartilage repair, this step being important to understand the function of engineered tissues. Current methods that use histological approaches are not always suited to tissue‐engineering analysis. We, therefore, set up a protocol to assess cell distribution, utilizing noninvasive confocal microscopy and fluorescent labels with a far red emission wavelength to optimize scaffold transparency and minimize light scattering. Hard (ceramic substitute) and soft (collagen sponge) biomaterials were seeded respectively, on one side of the scaffold, with human fibroblasts and bovine chondrocytes labelled with carbocyanine dyes (DiD and DiR). The mean penetration depth for DiR labelled fibroblasts and chondrocytes in the two scaffolds, around 270 m, was greater than for DiD (136–218 μm) labelled cells. These depths were independent of cell origin but were influenced by the nature of the scaffolds. Collagen sponge is transparent in contrast to ceramic substitutes where measurements could only be made in opened macropores. Besides the limits of the equipment, the limits of the supports were diffusion for collagen sponges and transmission for ceramic substitutes. Confocal microscopy techniques could thus be used to address the question of cell colonization of porous biomaterials in a noninvasive manner. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Human microvascular endothelial synthesis of interleukin‐8 during in vitro ischemia and reperfusion
Authors: Albadawi Hassan , Patton George M. , Bratton Charles F. , Peterson Brian G. , Watkins Michael T. 
Published: August 2006

AbstractThese studies were undertaken to evaluate human microvascular endothelial cell (MEC) synthesis of interleukin‐8 (IL‐8), a potent neutrophil chemoattractant, under in vitro conditions of ischemia and reperfusion. IL‐8 and other related CXC chemokines are believed to mediate tissue injury in a variety of pathologic conditions in humans. MEC grown on microcarrier beads were exposed to 3 or 6 h of in vitro ischemia followed by 2 h of reperfusion. Conditioned medium, MEC protein, and total RNA extracts were assayed for IL‐8 using an ELISA. During ischemia alone, MEC increased intracellular, but not extracellular levels of IL‐8 secretion. In contrast, reperfusion markedly stimulated both intracellular and extracellular IL‐8 secretion. Neither 3 h of ischemia alone or followed by reperfusion altered steady‐state levels of IL‐8 mRNA when compared to pre‐ischemic levels. In contrast, after 6 h of ischemia alone and ischemia followed by reperfusion, IL‐8 mRNA was increased eight‐ and sixfold, respectively, when compared to pre‐ischemic levels. These studies demonstrate an inverse relationship between the rate of IL‐8 protein secretion and the steady‐state levels of IL‐8 mRNA during ischemia and reperfusion. During ischemia and reperfusion both the increase in cell‐associated IL‐8 protein and the release of IL‐8 into the medium is dependent on de novo protein synthesis rather than the intracellular accumulation of IL‐8. These experiments indicate that post‐ischemic modulation of IL‐8 release and synthesis following ischemia reperfusion will require strategies directed towards inhibition of IL‐8 transcription and in depth knowledge of the mechanisms regulating IL‐8 secretion. J. Cell. Biochem. 100: 412–420, 2007. © 2006 Wiley‐Liss, Inc.
Suppression of fibroblast metalloproteinases by ajulemic acid, a nonpsychoactive cannabinoid acid
Authors: Johnson David R. , Stebulis Judith A. , Rossetti Ronald G. , Burstein Sumner H. , Zurier Robert B. 
Published: August 2006

AbstractProduction of matrix metalloproteinases (MMP) in joint tissue of patients with inflammatory arthritis facilitates cartilage degradation and bone erosion, and leads to joint deformities and crippling. Thus, MMPs are important targets for agents designed to treat inflammatory arthritis. Oral administration of ajulemic acid (AjA), a synthetic, nonpsychoactive cannabinoid acid, prevents joint tissue injury in rats with adjuvant arthritis. AjA binds to and activates PPARγ directly. Therefore, we investigated the influence of AjA on MMP production in human fibroblast‐like synovial cells (FLS), and examined the role of PPARγ in the mechanism of action of AjA. FLS, treated or not with a PPARγ antagonist, were treated with AjA then stimulated with TNFα or IL‐1α. Release of MMPs‐1, 3, and 9 was measured by ELISA. The influence of AjA on MMP‐3 release from stimulated PPARγ positive (PPAR+/−) and PPARγ null (PPAR−/−) mouse embryonic fibroblasts (MEF) was also examined. Addition of AjA to FLS suppressed production of MMPs whether or not PPARγ activation was blocked. Secretion of MMP‐3 was also suppressed by AjA in both TNFα‐ and IL‐1α‐stimulated PPARγ+/−and PPARγ−/−MEF. Suppression of MMP secretion from FLS by AjA appears to be PPARγ independent. Prevention by AjA of joint tissue injury and crippling in the rat adjuvant arthritis model may be explained in large part by inhibition of MMPs. These results suggest that AjA may be useful for treatment of patients with rheumatoid arthritis and osteoarthritis. J. Cell. Biochem. 100: 184–190, 2007. © 2006 Wiley‐Liss, Inc.
Iron chelation study in a normal human hepatocyte cell line suggests that tumor necrosis factor receptor‐associated protein 1 (TRAP1) regulates production of reactive oxygen species
Authors: Im Chang‐Nim , Lee Jae‐Seon , Zheng Ying , Seo Jeong‐Sun 
Published: August 2006

AbstractIron is an essential component of many proteins, and has crucial roles in the proper functioning of proteins involved in cellular respiration, proliferation, and differentiation. It has been recently reported that the deferoxamine (DFO), an iron chelator, induces mitochondrial dysfunction, characterized by an attenuation of oxidative phosphorylation, as well as senescence‐like cellular morphology. However, the effects of DFO on mitochondrial heat shock proteins (HSPs) remain poorly understood. In this study, we examined the effect of DFO on tumor necrosis factor receptor‐associated protein 1 (TRAP1), a representative mitochondrial HSP, in a normal human hepatocyte cell line, Chang cells. DFO specifically decreased TRAP1 levels, increasing reactive oxygen species (ROS) and caveolin‐1 (Cav‐1), a marker protein of senescence. To examine whether these effects of DFO are reversed, we established TRAP1‐overexpressing Chang cells. DFO treatment to TRAP1‐overexpressing cells resulted in decreases in levels of ROS, Cav‐1, glutathione peroxidase (GPX), and manganese superoxide dismutase (MnSOD) levels as well as senescence‐associated β‐galactosidase (SA β‐gal) activity. These results suggest that TRAP1 might play a role in protecting mitochondria against damaging stimuli via decrease of ROS generation. J. Cell. Biochem. 100: 474–486, 2007. © 2006 Wiley‐Liss, Inc.
Structural and biochemical advances in mammalian RNAi
Authors: Collins Robert E. , Cheng Xiaodong 
Published: August 2006

AbstractRNAi is a collection of processes mediated by small RNAs that silence gene expression in a sequence‐specific manner. Studies of processes as divergent as post‐transcriptional gene silencing, transcriptional silencing through RNA‐directed DNA methylation, or heterochromatin formation, and even RNA‐guided DNA elimination have converged on a core pathway. This review will highlight recent structural and mechanistic studies illustrating siRNA and miRNA processing, RISC formation, the execution of RNAi by RISC, and the regulation of these pathways, with a specific focus on vertebrate systems. J. Cell. Biochem. 99: 1251–1266, 2006. © 2006 Wiley‐Liss, Inc.
Induction of salivary polypeptides associated with parotid hypertrophy by gallotannins administered topically into the mouse mouth
Authors: Gho Francesca , Peña‐Neira Alvaro , López‐Solís Remigio O. 
Published: August 2006

AbstractIsoproterenol‐induced salivary polypeptides (IISP), a group of proline‐rich proteins synthesized by mouse parotids, have been considered as markers for isoproterenol‐induced parotid hypertrophy. Rodents fed diets containing high‐tannin cereals (sorghum), also develop parotid hypertrophy. To test whether tannins are directly involved in provoking sialotrophic growth, we studied the effect of intraperitoneal and topical oral administrations of tannic acid (TA) on the induction of IISP polypeptides in endogamic mice (A/Snell). TA was characterized by HPLC chromatography and spectral analysis and shown to be composed solely of gallotannins, a complex family of glucose and gallic acid esters. IISP polypeptides were monitored in saliva by SDS–polyacrylamide gel electrophoresis during 36 h after ending TA stimulation. Single daily intraperitoneal administrations of TA for 3 consecutive days (0.033 mg/g bw/day), at variance of parallel administrations of isoproterenol (0.042 mg/g bw/day) failed to induce IISP polypeptides. However, repeated topical applications of TA into the mouse mouths (1.21 mg/g bw divided into three equal doses given at 4‐h intervals within a single day) resulted in unequivocal induction of IISP polypeptides. That response was clearly intensified by increasing the stimulation frequency to eight equivalent doses given at 1.5‐h intervals within a single day (corresponding to 3.23 mg/g bw) and even further by repeating this protocol for 3 days. Under these productive schemes of stimulations by TA, electrophoretic fractionation of parotid homogenates showed new polypeptide bands migrating in parallel to salivary IISP. These results suggest that topically administered gallotannins are effective inducers of trophic growth in mouse parotids. J. Cell. Biochem. 100: 487–498, 2007. © 2006 Wiley‐Liss, Inc.
Activation of FAK is necessary for the osteogenic differentiation of human mesenchymal stem cells on laminin‐5
Authors: Salasznyk Roman M. , Klees Robert F. , Boskey Adele , Plopper George E. 
Published: August 2006

AbstractHuman mesenchymal stem cell (hMSC) differentiation into osteoblasts and the signaling events involved are poorly understood. We recently established that contact with specific extracellular matrix (ECM) proteins, in particular laminin‐5, is sufficient to induce an osteogenic phenotype in hMSC through an extracellular signal‐related kinase (ERK)‐dependent pathway. Activation of ERK 1/2 by laminin‐5 induces phosphorylation of the runx2/cbfa‐1 transcription factor that controls osteogenic gene expression. We hypothesized that focal adhesion kinase (FAK) mediated signaling pathways supply a link between cell surface integrin‐ECM binding and activation of ERK 1/2, and that laminin‐5 promotes its osteogenic effects through this pathway. To test this hypothesis, we plated hMSC on a laminin‐5 matrix in the presence or absence of FAK‐specific small inhibitory RNAs (siRNA), and assayed for phosphorylation of runx2/cbfa‐1 as well as expression of established osteogenic differentiation markers (bone sialoprotein, osteocalcin, alkaline phosphatase, calcium deposition, and mineral:matrix ratio). We found that siRNA treatment reduced total endogenous FAK protein by ∼40%, and reduced FAK phosphorylation on Y397 by ∼33% in cells plated on laminin‐5 for 30 min. SiRNA treated cells exhibited a decrease in ERK 1/2 phosphorylation after 1 h, and reduced serine/threonine phosphorylation of Runx2/Cbfa‐1 after 8 days. Finally, FAK inhibition blocked osteogenic differentiation of hMSC, as assessed by lowered expression of osteogenic genes (RT‐PCR), decreased alkaline phosphatase activity, greatly reduced calcium deposition, and a lower mineral:matrix ratio after 28 days in culture. These results establish FAK as an important mediator of laminin‐5‐induced osteogenic differentiation of hMSC. J. Cell. Biochem. 100: 499–514, 2007. © 2006 Wiley‐Liss, Inc.
Phosphatase PTEN is inactivated in bovine aortic endothelial cells exposed to cyclic strain
Authors: Hoshino Yuji , Nishimura Kengo , Sumpio Bauer E. 
Published: August 2006

AbstractHemodynamic forces, including cyclic strain (CS) and shear stress (SS), have been recognized as important modulators of vascular cell morphology and function. PTEN (also known as MMAC1/TEP1) is a lipid phosphatase that leads to a decrease in intracellular phosphatidylinositol 3,4,5 trisphosphate (PIP3) and therefore can modulate the stimulating effect of phosphatidylinositol 3‐kinase (PI3K). In this study, we focused on the upstream regulators of the PI3K‐Akt pathway by assessing Akt, PTEN, casein kinase 2 (CK2) (a kinase that catalyzes phosphorylation of PTEN), and PI3K activity in endothelial cells (EC) exposed to CS. The activity of phospho‐PTEN (n = 4) and phospho‐CK2 (n = 4) increased in a time‐dependent fashion, reaching maximal activity by 10 min of CS stimulation. The peak of phospho‐Akt activity (n = 4) occurred later, at 60 min. Akt activity was altered by transfection of EC with dominant negative PTEN plasmids. Furthermore, CS increased PIP3 immunoreactivity in a time‐dependent manner, reaching maximal activity after 60 min of CS stimulation, and these effects were affected by transfection of EC with dominant negative PTEN plasmids. Inhibition of PTEN activity had no effect on CS‐mediated cell proliferation but inhibited CS‐mediated suppression of apoptosis. J. Cell. Biochem. 100: 515–526, 2007. © 2006 Wiley‐Liss, Inc.
Effect of coagulation on palm oil mill effluent and subsequent treatment of coagulated sludge by anaerobic digestion
Authors: Krishnan Vijayaraghavan , Ahmad Desa , Endut Era Mayuza 
Published: August 2006

AbstractA new effluent treatment scheme is proposed for treating palm oil mill effluent based on coagulation and anaerobic digestion of coagulated sludge. The effectiveness of anionic (N9901) and cationic (N9907) polyelectrolytes manufactured by NALCO (Malaysia) was evaluated both as coagulant and coagulant aid. The results showed that the anionic and cationic polyelectrolytes were best suited as a coagulant aid, and the cationic polyelectrolyte showed better performance than the anionic polyelectrolyte. For an influent chemical oxygen demand (COD) concentration of 59 700 mg L−1 at an alum dosage of 1700 mg L−1, the residual COD, suspended solid removal, sludge volume and pH were found to be 39 665 mg L−1, 87%, 260 mL L−1 and 6.3, respectively. For the above influent COD and alum dosage with the addition of 2 mg L−1 of cationic polyelectrolyte as coagulant aid, the results were 30 870 mg L−1, 90%, 240 mL L−1 and 6.2, respectively. The sludge resulting from the coagulation process using alum as coagulant and cationic polyelectrolyte as coagulant aid was tested for its digestibility in an anaerobic digester. The quantity of biogas generated per gram of volatile solids (VS) destroyed at a loading rate of 26.7 ± 0.5 and 35.2 ± 0.4 g VS L−1 d−1 was found to be 0.68 and 0.72 L g−1 VS destroyed. The anaerobic biomass when subjected to varying alum dosage in the coagulated palm oil sludge did not exhibit inhibition as the digester performance was in conformity with the regular treatment process Copyright © 2006 Society of Chemical Industry
Syntheses of [14C]BAY 59‐7939 and its radiolabeled metabolite M‐4
Authors: Pleiss U. , Seidel D. , Grosser R. 
Published: August 2006

AbstractBAY 59‐7939 is a novel, oral, direct Factor Xa inhibitor in clinical development for the prevention and treatment of thromboembolic diseases. Radiolabeled BAY 59‐7939 was required for drug absorption, distribution, metabolism and excretion (ADME studies). The BAY 59‐7939 was labeled with carbon‐14 in the carboxamide group in one step in an overall radiochemical yield of 85% starting from 4‐{4‐[(5S)‐5‐(aminomethyl)‐2‐oxo‐1,3‐oxazolidin‐3‐yl]phenyl}mor‐pholin‐3‐one and 5‐chlorothiophene‐2‐[14C]carboxylic acid. The radiolabeled metabolite M‐4 was prepared in 77% yield starting from [1‐14C]glycine and 5‐chlorothiophene‐5‐carboxylic acid. Copyright © 2006 John Wiley & Sons, Ltd.
Characterization of coronary atherosclerotic plaque using multicontrast MRI acquired under simulated in vivo conditions
Authors: Sun Binjian , Giddens Don P. , Long Robert , Taylor W. Robert , Weiss Diana , Joseph Giji , Vega David , Oshinski John N. 
Published: August 2006

AbstractPurposeTo compare coronary atherosclerotic plaque characterization using multicontrast MRI on: 1) freshly excised vessels under simulated in vivo conditions, and 2) preserved vessels.Materials and MethodsT1‐weighted (T1W), T2‐weighted (T2W), proton density‐weighted (PDW), and diffusion‐weighted (DW) MR images were acquired on 13 freshly excised human coronary arteries from explanted hearts. Vessels were imaged in an MR‐compatible tissue culture chamber using a 4.7 Tesla small‐bore MR scanner. Eight vessels were then preserved in buffered formalin and rescanned following the same imaging protocol. A three‐dimensional spatially penalized fuzzy C‐means (3D‐SPFCM) technique was applied to classify different plaque constituents. The classification results from vessels under “fresh” and “preserved” conditions were compared with corresponding histological sections.ResultsFor most plaque constituents, the plaque characterization results show no significant difference between fresh and preserved scans, and little difference between scans and the histological reference standard. In the case of thrombus, apparent signal changes between fresh and preserved images were identified. Overall, MR scans conducted under preserved conditions provided a 1.8% to 17.5% greater signal‐to‐noise ratio (SNR) than those conducted in the fresh stage.ConclusionPreservation of coronary vessels did not alter the contrast between plaque tissues on multicontrast MRI, and did not significantly change the results of plaque constituent characterization. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
A knowledge‐guided active model method of cortical structure segmentation on pediatric MR images
Authors: Shan Zuyao Y. , Parra Carlos , Ji Qing , Jain Jinesh , Reddick Wilburn E. 
Published: August 2006

AbstractPurposeTo develop an automated method for quantification of cortical structures on pediatric MR images.Materials and MethodsA knowledge‐guided active model (KAM) approach was proposed with a novel object function similar to the Gibbs free energy function. Triangular mesh models were transformed to images of a given subject by maximizing entropy, and then actively slithered to boundaries of structures by minimizing enthalpy. Volumetric results and image similarities of 10 different cortical structures segmented by KAM were compared with those traced manually. Furthermore, the segmentation performances of KAM and SPM2, (statistical parametric mapping, a MATLAB software package) were compared.ResultsThe averaged volumetric agreements between KAM‐ and manually‐defined structures (both 0.95 for structures in healthy children and children with medulloblastoma) were higher than the volumetric agreement for SPM2 (0.90 and 0.80, respectively). The similarity measurements (kappa) between KAM‐ and manually‐defined structures (0.95 and 0.93, respectively) were higher than those for SPM2 (both 0.86).ConclusionWe have developed a novel automatic algorithm, KAM, for segmentation of cortical structures on MR images of pediatric patients. Our preliminary results indicated that when segmenting cortical structures, KAM was in better agreement with manually‐delineated structures than SPM2. KAM can potentially be used to segment cortical structures for conformal radiation therapy planning and for quantitative evaluation of changes in disease or abnormality. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Contrast‐driven approach to intracranial segmentation using a combination of T2‐ and T1‐weighted 3D MRI data sets
Authors: Helms Gunther , Kallenberg Kai , Dechent Peter 
Published: August 2006

AbstractPurposeTo develop a strategy for structural brain imaging when using FSL software for segmentation and subsequent volumetry.Materials and MethodsThree‐dimensional (3D) structural MRI of 1‐mm isotropic resolution was performed on a 3‐Tesla clinical imaging system. Prescribed signal evolution of a multiple spin‐echo (SE) sequence with variable refocusing flip angle for T2 weighting, and a modified driven equilibrium Fourier transform (MDEFT) sequence were used for T1 weighting. Postprocessing included rigid‐body coregistration, brain extraction, and segmentation using the tools of the FSL 3.2 software package.ResultsT2 weighting provided reliable delineation of the subarachnoidal space, while T1 weighting provided better segmentation of gray matter (GM) and white matter (WM). The combination of T1‐weighted (T1‐w) and T2‐w data allowed the identification of a T2‐hypointense class of “nonbrain” (NB) representing larger vessels and structures of connective tissue, as well as partial volume of bone and air‐filled cavities.ConclusionBrain extraction on T2‐w data and subsequent segmentation of the combined T1‐ and T2‐w intensity distribution into four classes are recommended. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.