bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of titanium dioxide on the oxidative metabolism of alveolar macrophages: An experimental study in rats
Authors: Olmedo Daniel G. , Tasat Deborah R. , Guglielmotti María B. , Cabrini Rómulo L.
Published: March 2005

Metallic implants of titanium are used therapeutically in biomedicine because of its excellent biocompatibility. However, no metal or alloy is completely inert. We have previously shown that titanium oxide (TiO2) is transported in blood by phagocytic monocytes and deposited in organs such as liver, spleen, and lung 6 months after intraperitoneal injection (ip). Furthermore, it is well known that exposure to metal traces alters the cellular redox status. Thus, the aim of the present study was to determine the presence of titanium in target organs after chronic exposure, assess the potential structural alterations, and evaluate the oxidative metabolism of alveolar macrophages (AM) in the lung. Rats were ip injected with 1.60 g/100 g body wt of TiO2 in saline solution. Organs (liver, spleen, lung) were processed for histological evaluation. Reactive oxygen species (ROS) in AM obtained by bronchoalveolar lavage (BAL) were evaluated using the nitroblue tetrazolium test and quantitative evaluation by digital image analysis. The histological analysis of organs revealed the presence of titanium in the parenchyma of these organs with no associated tissue damage. Although in lung alveolar macrophages TiO2 induced a significant rise in ROS generation, it failed to cause tissue alteration. This finding may be attributed to an adaptive response. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 142–149, 2005
Stress ratio contributes to fatigue crack growth in dentin
Authors: Arola D. , Zheng W. , Sundaram N. , Rouland J.A.
Published: March 2005

An experimental study of fatigue crack growth in dentin was conducted, and the influence of stress ratio (R) on the crack growth rate and mechanisms of cyclic extension were examined. Double Cantilever Beam (DCB) fatigue specimens were sectioned from bovine molars and then subjected to high cycle fatigue loading (105 < N < 106) under hydrated conditions. The evaluation consisted of Mode I loads with stress ratios that ranged from −0.5 to 0.5. The fatigue crack growth rates were measured and used to estimate the crack growth exponent (m) and coefficient (C) according to the Paris Law model. The fatigue crack growth rates for steady‐state extension (Region II) ranged from 1E‐7 to 1E‐4 mm/cycle. It was found that the rate of cyclic extension increased significantly with increasing R, and that the highest average crack growth rate occurred at a stress ratio of 0.5. However, the crack growth exponent decreased with increasing R from an average of 4.6 (R = 0.10) to 2.7 (R = 0.50). The stress intensity threshold for crack growth decreased with increasing R as well. Results from this study suggest that an increase in the cyclic stress ratio facilitates fatigue crack growth in dentin and increases the rate of cyclic extension, both of which are critical concerns in minimizing tooth fractures and maintaining lifelong oral health. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 201–212, 2005
The influence of various occlusal materials on stresses transferred to implant‐supported prostheses and supporting bone: A three‐dimensional finite‐element study
Authors: Sevimay Mujde , Usumez Aslihan , Eskitascıoglu Gurcan
Published: March 2005

The aim of this numerical analysis was to evaluate the amount and localization of stress that occurs with various materials used in implant‐crown design under functional forces. Computer‐aided design techniques and a finite‐element stress analysis method were used for evaluation. A 4.1 × 10‐mm implant placed in the mandibular second premolar area was simulated and analyzed. Simulation and analysis were performed with the use of COSMOS/M software and Pro/Engineer 2000i on a Dual Pentium III 1‐GHz computer. Crown designs were as follows: porcelain fused to noble metal crown, porcelain fused to base metal crown, In‐Ceram porcelain crown, and IPS Empress 2 porcelain crown. A 300‐N vertical force was applied to the centric relation stop points of the crowns. The results of this study indicated that different types of restorative materials play an important role in the amount and distribution of the stresses in the superstructure and the implant. The highest stress values were observed in the IPS Empress 2 porcelain crown design (600 MPa). Porcelain fused to base metal and In‐Ceram framework designs transferred less stress to abutment. Type of restorative materials used in implant crown designs are significant factors in the amount and distribution of the stresses on superstructure and implant under functional forces. Porcelain fused to base metal (149 MPa) and In‐Ceram (173 MPa) crown designs induced higher von Mises stress values within the framework than porcelain fused to noble metal (108 MPa) and IPS Empress 2 (119 MPa) porcelain crown designs. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 73B: 140–147, 2005
Wear analysis of retrieved ceramic‐on‐ceramic articulations in total hip arthroplasty: Femoral head makes contact with the rim of the socket outside of the bearing surface
Authors: Yamamoto Tetsuya , Saito Masanobu , Ueno Masaru , Hananouchi Takehito , Tokugawa Yusuke , Yonenobu Kazuo
Published: March 2005

We investigated articular bearing surfaces retrieved from three patients with ceramic‐on‐ceramic total hip arthroplasties using high‐quality alumina. The duration of implantation was 3.5, 3.0, and 2.5 years, respectively. Dislocation of the hip joint after implantation did not occur in any patients. The retrieved prostheses were examined by stereomicroscopy and scanning electron microscopy (SEM). In the main load‐bearing area, no wear marks were seen in any sockets. However, in all three cases, stripe scars were observed at the rim of the alumina inlay under stereomicroscopy, despite the lack of indentation in the socket and the stem, which suggests impingement. Such scars were not observed on the load‐bearing surface. Under SEM, the scars showed excessive wear, including material excavation, that has not been observed in conventional hip simulator experiments. These findings are similar to those of experiments in which a simulator was programmed to distract the femoral head from the socket. The present results suggest that the femoral head can separate from the socket without neck‐socket impingement in vivo. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Discoloration of dental resin composites after immersion in a series of organic and chemical solutions
Authors: Lee Yong‐Keun , Powers John M.
Published: March 2005

The objective of this study was to evaluate the color change of dental resin composites following a series of immersion treatments, especially in organic substances. The color of four resin composites was measured according to the CIELAB color scale relative to the standard illuminant D65. Color was measured at baseline, and after sequential immersion in the following substances: Step 1, porcine‐liver esterase (a substitute for a salivary esterase); Step 2, organic substances (mucin and serum) and phosphate‐buffered saline (PBS) as a control; Step 3, chemical alteration agents [chlorhexidine (CH) and carbamide peroxide (CP)]; and Step 4, 2% methylene blue. Porcine‐liver esterase caused color changes (ΔE) of 0.7–1.1 from the baseline. Organic substances caused color changes of 0.4–1.8 from the baseline, and color changes in organic substances were not significantly higher than those in PBS (p > 0.05), except for one composite. Combined treatment with mucin (or serum) with CH (or CP) did not produce significantly higher color changes compared to controls (p > 0.05). Mucin‐treated composites showed generally lower methylene blue staining compared to serum and PBS groups. Although combined treatment of organic substances and chemical agents resulted in various discolorations of resin composites, chemical alteration of organic substances did not produce higher color change compared to PBS controls. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Corrosion behavior of cast Ti‐6Al‐4V alloyed with Cu
Authors: Koike Marie , Cai Zhuo , Oda Yutaka , Hattori Masayuki , Fujii Hiroyuki , Okabe Toru
Published: March 2005

It has recently been found that alloying with copper improved the inherently poor grindability and wear resistance of titanium. This study characterized the corrosion behavior of cast Ti‐6Al‐4V alloyed with copper. Alloys (0.9 or 3.5 mass % Cu) were cast with the use of a magnesia‐based investment in a centrifugal casting machine. Three specimen surfaces were tested: ground, sandblasted, and as cast. Commercially pure titanium and Ti‐6Al‐4V served as controls. Open‐circuit potential measurement, linear polarization, and potentiodynamic cathodic polarization were performed in aerated (air + 10% CO2) modified Tani‐Zucchi synthetic saliva at 37°C. Potentiodynamic anodic polarization was conducted in the same medium deaerated by N2 + 10% CO2. Polarization resistance (Rp), Tafel slopes, and corrosion current density (Icorr) were determined. A passive region occurred for the alloy specimens with ground and sandblasted surfaces, as for CP Ti. However, no passivation was observed on the as‐cast alloys or on CP Ti. There were significant differences among all metals tested for Rp and Icorr and significantly higher Rp and lower Icorr values for CP Ti compared to Ti‐6Al‐4V or the alloys with Cu. Alloying up to 3.5 mass % Cu to Ti‐6Al‐4V did not change the corrosion behavior. Specimens with ground or sandblasted surfaces were superior to specimens with as‐cast surfaces. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Attaining exponential convergence for the flux error with second‐ and fourth‐order accurate finite‐difference equations. I. Presentation of the basic concept and application to a pure diffusion system
Authors: Rudolph Manfred
Published: March 2005

It is a well‐known phenomenon called superconvergence in the mathematical literature that the error level of an integral quantity can be much smaller than the magnitude of the local errors involved in the computation of this quantity. When discretizing an integrated form of Fick's second law of diffusion the local errors reflect the accuracy of individual concentration points while the integral quantity has the physical meaning of the flux. This article demonstrates how an extraordinary fast exponential convergence towards zero can be achieved for the simulated flux error on the basis of finite–difference approximations that are only second‐order (Box 2 method) or fourth‐order (Box 4 method) accurate as far as the level of local errors is concerned. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 619–632, 2005
Attaining exponential convergence for the flux error with second‐ and fourth‐order accurate finite‐difference equations. II. Application to systems comprising first‐order chemical reactions
Authors: Rudolph Manfred
Published: March 2005

This article demonstrates that exponential convergence of the flux error can be achieved for any kinetic–diffusion system comprising an arbitrary number of (pseudo) first‐order chemical reactions if the underlying PDEs are discretized as outlined for the box 2 or box 4 method in the preceding part of this article. By investigating the eigenvalues and eigenvectors of the first‐order kinetic coupling matrix in general form the present article demonstrates that the simulation of any multispecies first‐order kinetic diffusion system can be as accurately done as the simulation of a single representative one‐species system. The Fourier coefficients governing the error level of the flux are much smaller in the limiting case of kinetic control as those reported in the preceding article for the limiting case of diffusion control. The higher rate of exponential convergence predicted on the basis of the mathematical model has been fully verified by the numerical results. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 633–641, 2005
Orthogonal designs, self‐dual codes, and the Leech lattice
Authors: Harada Masaaki , Kharaghani Hadi
Published: March 2005

Symmetric designs and Hadamard matrices are used to construct binary and ternary self‐dual codes. Orthogonal designs are shown to be useful in construction of self‐dual codes over large fields. In this paper, we first introduce a new array of order 12, which is suitable for any set of four amicable circulant matrices. We apply some orthogonal designs of order 12 to construct new self‐dual codes over large finite fields, which lead us to the odd Leech lattice by Construction A. © 2005 Wiley Periodicals, Inc. J Combin Designs 13: 184–194, 2005.
Smart materials as scaffolds for tissue engineering
Authors: Rosso Francesco , Marino Gerardo , Giordano Antonio , Barbarisi Manlio , Parmeggiani Domenico , Barbarisi Alfonso
Published: March 2005

In this review, we focused our attention on the more important natural extracellular matrix (ECM) molecules (collagen and fibrin), employed as cellular scaffolds for tissue engineering and on a class of semi‐synthetic materials made from the fusion of specific oligopeptide sequences, showing biological activities, with synthetic materials. In particular, these new “intelligent” scaffolds may contain oligopeptide cleaving sequences specific for matrix metalloproteinases (MMPs), integrin binding domains, growth factors, anti‐thrombin sequences, plasmin degradation sites, and morphogenetic proteins. The aim was to confer to these new “intelligent” semi‐synthetic biomaterials, the advantages offered by both the synthetic materials (processability, mechanical strength) and by the natural materials (specific cell recognition, cellular invasion, and the ability to supply differentiation/proliferation signals). Due to their characteristics, these semi‐synthetic biomaterials represent a new and versatile class of biomimetic hybrid materials that hold clinical promise in serving as implants to promote wound healing and tissue regeneration. © 2005 Wiley‐Liss, Inc.
Diverse isoforms of colony‐stimulating factor‐1 have different effects on the development of stroma‐dependent hematopoietic cells
Authors: Friel Jutta , Heberlein Christoph , Geldmacher Maren , Ostertag Wolfram
Published: March 2005

Maintenance and differentiation of hematopoietic stem and progenitor cells are controlled by complex interactions with the stroma microenvironment. Stroma–cell interactions can be supported by locally expressed membrane‐spanning cell‐surface (cs) growth factors. CSF‐1 is expressed by stroma as a soluble glycoprotein, as proteoglycan, or as a membrane‐spanning cs glycoprotein. CSF‐1 regulates the survival, proliferation, and differentiation of mononuclear phagocytes. Whereas the biological role of soluble CSF‐1 is well characterized, the function of the membrane‐spanning cell‐surface CSF‐1 (csCSF‐1) remains unclear. To analyze the biological significance of csCSF‐1 in vitro, we used an epithelial cell line to ectopically express the different CSF‐1 isoforms. In co‐cultures of CSF‐1 transduced epithelial cells with primary, early hematopoietic progenitor cells we examined whether interaction between csCSF‐1 and its receptor mediates cell proliferation, self‐renewal, or differentiation. csCSF‐1 induces long‐lasting proliferation of stimulated cells and furthermore supports self‐renewal. Ectopic secretion of soluble CSF‐1 does not permit long‐term growth of progenitor cells but induces differentiation of monocytes into macrophages. Previously, we showed that the soluble and cs isoforms of stroma‐encoded SCF differently affect the development of hematopoietic cells. Cell‐surface SCF (csSCF) promotes self‐renewal of stimulated cells whereas soluble SCF causes clonal extinction. These results and those presented here for CSF‐1 provide evidence for diverse functions of the isoforms of the ligands SCF and CSF‐1 for two tyrosine kinase receptors of the subclass III both regulating hematopoiesis on stroma. J. Cell. Physiol. 204: 247–259, 2005. © 2005 Wiley‐Liss, Inc.
Identification of in vivo P‐glycoprotein mRNA decay intermediates in normal liver but not in liver tumors
Authors: Lee Chow H. , Rehaume Vicki E. , Shandro Janis
Published: March 2005

Post‐transcriptional regulation at the level of mRNA stability is one important mechanism for over‐expression of P‐glycoprotein (Pgp) genes observed in cultured cells and in animals. A previous study has shown that mRNA half‐lives for Pgp genes in normal liver were less than 2 h, in contrast to greater than 12 h measured in a transplantable liver tumor line. This lower turnover rate of Pgp mRNA may, in large part, contribute to the abundance of Pgp mRNA in liver tumors. The current study sought to investigate the underlying mechanism for the lower turnover rate of Pgp2 mRNA previously determined in liver tumors. As a first approach, we set out to understand the Pgp2 mRNA decay in both normal liver and liver tumors by first identifying and characterizing Pgp2 mRNA degradation intermediates. In this study, we showed that the sensitive ligation‐mediated polymerase chain reaction (LM‐PCR) method can be used to detect a homogenous pool of in vitro transcribed RNA down to 0.4 ng. By employing gene‐specific primers in the LM‐PCR method, we successfully identified four Pgp2 mRNA decay intermediates in normal liver. All four decay intermediates detected correspond to the 5′ coding region of Pgp2 mRNA, and surprisingly no decay intermediates which correspond to 3′ untranslated region, 3′ coding region or middle coding region were found using LM‐PCR. The identified decay intermediates are unique to the normal liver as they were absent or present at very low level in all three liver tumor samples analyzed. This observation supports our previous findings that the Pgp mRNA turnover rate is lower in liver tumors than in normal liver. These findings have implications for our understanding of the regulation of Pgp mRNA turnover in normal and malignant tissues. © 2005 Wiley‐Liss, Inc.
Regulatory networks for the control of body iron homeostasis and their dysregulation in HFE mediated hemochromatosis
Authors: Ludwiczek Susanne , Theurl Igor , Bahram Siamak , Schümann Klaus , Weiss Günter
Published: March 2005

Although the recent identification of several genes has extended our knowledge on the maintenance of body iron homeostasis, their tissue specific expression patterns and the underlying regulatory networks are poorly understood. We studied C57black/Sv129 mice and HFE knockout (HFE −/−) variants thereof as a model for hemochromatosis, and investigated the expression of iron metabolism genes in the duodenum, liver, and kidney as a function of dietary iron challenge. In HFE +/+ mice dietary iron supplementation increased hepatic expression of hepcidin which was paralleled by decreased iron regulatory protein (IRP) activity, and reduced expression of divalent metal transporter‐1 (DMT‐1) and duodenal cytochrome b (Dcytb) in the enterocyte. In HFE −/− mice hepcidin formation was diminished upon iron challenge which was associated with decreased hepatic transferrin receptor (TfR)‐2 levels. Accordingly, HFE −/− mice presented with high duodenal Dcytb and DMT‐1 levels, and increased IRP and TfR expression, suggesting iron deficiency in the enterocyte and increased iron absorption. In parallel, HFE −/− resulted in reduced renal expression of Dcytb and DMT‐1. Our data suggest that the feed back regulation of duodenal iron absorption by hepcidin is impaired in HFE −/− mice, a model for genetic hemochromatosis. This change may be linked to inappropriate iron sensing by the liver based on decreased TfR‐2 expression, resulting in reduced circulating hepcidin levels and an inappropriate up‐regulation of Dcytb and DMT‐1 driven iron absorption. In addition, iron excretion/reabsorption by the kidneys may be altered, which may aggravate progressive iron overload. © 2005 Wiley‐Liss, Inc.
D‐aspartate modulates transcriptional activity in Harderian gland of frog, Rana esculenta: Morphological and molecular evidence
Authors: Raucci Franca , Santillo Alessandra , D'Aniello Antimo , Chieffi Paolo , Baccari Gabriella Chieffi
Published: March 2005

In the green frog, Rana esculenta, a substantial amount of D‐aspartate (D‐Asp) is found endogenously within the Harderian gland (HG) following its synthesis from L‐aspartate (L‐Asp) by an aspartate racemase. The frog HG is an orbital seromucoid gland that displays seasonal changes in secretory activity. Our in vivo experiments, consisting of i.p. injection of 2.0 μmol/g b.w. D‐Asp in frogs collected during two periods of differing glandular activity (high or medium‐low secretory activity), revealed that HG can to take up and accumulate D‐Asp and that this amino acid may modulate the exocrine secretion through a kinase pathway. At a time when the gland shows relatively low secretory activity, i.p. administration of D‐Asp rapidly induced activation of ERK1 and an increase in cells active in RNA synthesis. This increase in transcriptional activity was followed by a significant increase in mucous secretion. By contrast, administration of exogenous D‐Asp when HG was showing high activity rapidly induced inhibition of both ERK1 and transcriptional activity. Since D‐Asp is known to be recognized by receptors for N‐methyl‐D‐aspartic acid (NMDA), it is possible that in the HG, D‐Asp mediated NMDA activation may enhance the kinase pathway. The above activation of opposing stimulatory and inhibitory processes could reflect different levels of NMDA‐receptor activity, which could vary as a function of the level of gland activity. This study provides the first evidence of a role for this excitatory amino acid in exocrine secretion. The effects of D‐Asp in HG appear to be specific since they were not seen in frogs treated with other D‐ or L‐amino acids with known excitatory effects on neurosecretion. © 2005 Wiley‐Liss, Inc.
Regulatory and necrotic volume increase in boar spermatozoa
Authors: Petrunkina A.M. , Jebe E. , Töpfer‐Petersen E.
Published: March 2005

Spermatozoa of many species initially respond to hypotonicity as perfect osmometers. Thereafter they undergo a regulatory process resulting in a decrease in cell volume, similar to that reported for somatic cells. Regulatory volume increase (RVI), a complementary process which is assumed to occur following initial shrinkage of sperm volume after exposure to a hypertonic medium, has not yet been described in detail for spermatozoa. In this study, we investigated whether spermatozoa are able to regulate their volume after hypertonic stress and whether this ability is maintained in preserved sperm. Cell volume changes were recorded using electronic cell sizing. Sperm response to the ion channels blockers quinidine, tamoxifen, and dydeoxyforskolin, and to protein kinase/phosphatase inhibitors lavendustin, staurosporine, and vanadate was studied to investigate possible mechanisms of RVI. Annexin V staining was used in combination with propidium iodide to determine whether hypertonic stress may induce apoptosis. Overall protein tyrosine phosphorylation under hypertonic conditions was measured via flow cytometry using antiphosphotyrosine antibody. Spermatozoa exposed to hypertonic stress initially responded with an abundant subpopulation according to the perfect osmometer model and recovered their volume from this shrinkage after 20 min. RVI was inhibited by quinidine and tamoxifen, which indicates the involvement of the important cellular ions sodium and chloride in this process. Volume regulatory ability was essentially maintained during storage of liquid semen. However, the response of the sperm population was heterogeneous. A second population raised, containing spermatozoa with larger volumes, which demonstrated irregularities in the volume response with respect to osmotic challenge, ion channel blockers, and storage. Under hypertonic conditions, both protein kinase inhibitors (PKI) led to increased isotonic volumes and to elevated initial relative volumes and subsequent volume decrease. RVI was inhibited by the vanadate. Hypertonic stress did not result in an increase in early apoptotic cells, but produced a shift toward late necrotic cells. Substitution of sodium and chloride by choline and sulfate resulted in decreased isotonic volume of sperm treated with lavendustin. Tyrosine phosphorylation levels were reduced after 20 min under hypertonic conditions. It was concluded that RVI is regulated via a protein tyrosine kinase‐dependent pathway, and that dephosphorylation occurs when volume regulation is required. The necrotic volume increase (NVI) is associated with the accumulation of sodium and chloride following uncontrolled opening of the channels. The ability to regulate volume after exposure to hypertonic conditions is important for sperm functionality and can have practical applications in spermatological diagnostics and cryopreservation. © 2005 Wiley‐Liss, Inc.
Stem cells and pulmonary metamorphosis: New concepts in repair and regeneration
Authors: Aliotta Jason M. , Passero Michael , Meharg Joseph , Klinger James , Dooner Mark S. , Pimentel Jeffrey , Quesenberry Peter J.
Published: March 2005

Adult stem cells are likely to have much more versatile differentiation capabilities than once believed. Numerous studies have appeared over the past decade demonstrating the ability of adult stem cells to differentiate into a variety of cells from non‐hematopoietic organs, including the lung. The goal of this review is to provide an overview of the growth factors which are thought to be involved in lung development and disease, describe the cells within the lung that are believed to replace cells that have been injured, review the studies that have demonstrated the transformation of bone marrow‐derived stem cells into lung cells, and describe potential clinical applications with respect to human pulmonary disease. © 2005 Wiley‐Liss, Inc.
Characterization of five evolutionary conserved regions of the human tyrosine hydroxylase (TH) promoter: Implications for the engineering of a human TH minimal promoter assembled in a self‐inactivating lentiviral vector system
Authors: Romano Gaetano , Suon Sokreine , Jin Hao , Donaldson Angela E. , Iacovitti Lorraine
Published: March 2005

A DNA fragment of about 13 kb containing the human tyrosine hydroxylase (TH) promoter was previously isolated from a genomic DNA library and sequenced. The 11 kb from the transcription start of the human TH promoter was successively joined to the green fluorescent protein (GFP) to generate a transgenic mouse model. High levels of GFP expression could be observed in TH‐positive cells of the Substantia nigra of embryonic and adult mice. Intriguingly, the sequence of the human TH promoter showed a low degree of homology with the mouse and rat TH promoters. In fact, comparative analysis of the sequences of human, rat, and mouse TH promoters revealed only five small regions of high homology. These five evolutionarily conserved regions were numbered in numeric progression from the 5′ end of human TH promoter. In the present study, a panel of minimal human TH promoters was generated to analyze the transcriptional activity and specificity of gene expression conferred by the five conserved regions (CRs). The series of constructs was termed 250 bp and contained the first −194 bp of the human TH promoter immediately upstream of the transcription start, the first 35 bp the human TH messenger RNA leader, plus one or more of the five CRs. All the constructs were assembled in a self‐inactivating form of the latest series of lentiviral vector system based on the human immunodeficiency virus type 1 (HIV‐1). Lentiviral‐mediated gene transfer was highly efficient for the in vitro transduction of human neuronal progenitor cells (hNPCs). Since a subset of hNPCs express TH following in vitro treatment with a mixture of differentiating agents, it was possible to assess specificity of expression for all the minimal human TH promoters. Overall, the successive addition of the five conserved regions produced a greater degree of specificity in induced TH‐positive hNPCs, in particular after the addition of CRI (−8,917, −8,876). However, the human TH minimal promoters did not show any specificity for TH‐positive differentiated mouse primary striatal and S. nigra cells, indicating a difference of TH gene regulation between the human and mouse systems. The human TH minimal promoters may provide the opportunity for the selection of TH‐positive human embryonic and adult stem cells for brain transplantation experiments in animal models for Parkinson's disease. © 2005 Wiley‐Liss, Inc.
Three‐dimensional culture of melanoma cells profoundly affects gene expression profile: A high density oligonucleotide array study
Authors: Ghosh Sourabh , Spagnoli Giulio C. , Martin Ivan , Ploegert Sabine , Demougin Philippe , Heberer Michael , Reschner Anca
Published: March 2005

Growth in three‐dimensional (3D) architectures has been suggested to play an important role in tumor expansion and in the resistance of cancers to treatment with drugs or cytokines or irradiation. To obtain an insight into underlying molecular mechanisms, we addressed gene expression profiles of NA8 melanoma cells cultured in bidimensional monolayers (2D) or in 3D multicellular tumor spheroids (MCTS). MCTS containing 10‐30,000 cells were generated upon overnight culture in poly‐Hydroxyethylmethacrylate (polyHEMA) coated plates. Kinetics of cell proliferation in MCTS was significantly slower than in monolayer cultures. Following long‐term culture (>10 days), however, MCTS showed highly compact and organised cell growth in outer layers, with necrotic cores. Oligonucleotide microarray analysis of the expression of over 20,000 genes was performed on cells cultured in standard 2D, in the presence of collagen as model of extracellular matrix (ECM), or in MCTS. Gene expression profiles of cells cultured in 2D in the presence or absence of ECM were highly similar, with ≥threefold differences limited to five genes. In contrast, culture in MCTS resulted in the significant, ≥threefold, upregulation of the expression of >100 transcripts while 73 were ≥threefold downregulated. In particular, genes encoding CXCL1, 2, and 3 (GRO‐α, ‐β, and γ), IL‐8, CCL20 (MIP‐3α), and Angiopoietin‐like 4 were significantly upregulated, whereas basic FGF and CD49d encoding genes were significantly downregulated. Oligonucleotide chip data were validated at the gene and protein level by quantitative real‐time PCR, ELISA, and cell surface staining assays. Taken together, our data indicate that structural modifications of the architecture of tumor cell cultures result in a significant upregulation of the expression of a number of genes previously shown to play a role in melanoma progression and metastatic process. © 2005 Wiley‐Liss, Inc.
Effects of development and iron status on ceruloplasmin expression in rat brain
Authors: Chang Yan Zhong , Qian Zhong Ming , Wang Kui , Zhu Li , Yang Xiao Da , Du Jin Rong , Jiang Lin , Ho Kwok Ping , Wang Qin , Ke Ya
Published: March 2005

The increased iron content in the brain of subjects with aceruloplasminemia has implicated ceruloplasmin (CP) as a major factor in the regulation of regional brain iron content. In this study, we investigated the effects of age and iron on CP expression in rat brain. In all four regions, the iron concentrations increased with developmental age. There is a similar trend in age‐induced changes in CP mRNA and protein. The CP mRNA and protein levels were both lowest at postnatal day (PND) 7. The expression increased gradually with age, reaching the highest at PND196 in the striatum and substantia nigra, and at PND21 and PND63 in the cortex and hippocampus, respectively. This suggests the existence of an age‐dependent pre‐transcriptional regulation and a regionally specific effect of age on CP expression in the brain. Although total iron in all four regions was significantly lower in the rats fed with a low‐iron diet for 6 weeks and higher in the rats with a high‐iron diet than those in the control animals, no significant between‐group differences in CP mRNA and protein were found in these animals, except in the substantia nigra where a significant increase in CP protein in high‐iron rats was observed, and the reverse in low‐iron rats. These findings suggested that the effects of iron on CP expression in the brain may be region‐specific, and that regulation of CP expression by iron in the substantia nigra was at the post‐transcriptional level. © 2005 Wiley‐Liss, Inc.
Bone and cartilage formation by skeletal muscle derived cells
Authors: Mastrogiacomo M. , Derubeis A.R. , Cancedda R.
Published: March 2005

In adult individuals when most tissues have progressively lost the ability to regenerate, bone maintains the potential for a continuous self remodeling. The bone marrow has been so far the main recognized source of osteoprogenitor cells that contribute to the turnover of the skeletal scaffold. The possibility though exists that a pool of osteoprogenitor cells resides within other adult tissues and in particular, as reported previously, in other connective tissues such as fat and skeletal muscle. In an attempt to identify an alternative source of osteoprogenitor cells other than bone marrow we looked into the skeletal muscle. A plastic adhering cell population, from now on referred to as skeletal muscle derived cells (SMDCs), was obtained from biopsies of human skeletal muscle. SMDCs were clonogenic and displayed a fibroblast‐like morphology. The isolated cell population had a mesenchymal origin as indicated by abundant expression of type I collagen, fibronectin, and vimentin and appeared heterogeneous. SMDCs were positive for α smooth actin, and to a lesser extent for desmin and α sarcomeric myosin, two specific markers of the myogenic phenotype. Surprisingly though SMDCs expressed early markers of an osteogenic commitment as indicated by positive staining for alkaline phosphatase, osteopontin, and osteonectin. Under the appropriate stimuli, these cells deposited in vitro a mineralized bone matrix and a proteoglycan rich matrix. In addition, SMDCs cultured in the presence of low serum and insulin differentiated towards adipocytes developing abundant lipid droplets in the cytoplasm. Furthermore SMDCs formed three‐dimensional bone tissue in vivo when implanted in an immunodeficient mouse, and a mature cartilage rudiment when maintained as a pellet culture. In summary, we report the isolation and characterization of a cell population from the human skeletal muscle not only able to express in vitro specific markers of distinct mesenchymal lineages (adipogenic, chondrogenic, and osteogenic), but most importantly, able to complete the differentiation pathway leading to the formation of bone and cartilage. In this respect SMDCs resemble bone marrow stromal cells (BMSCs). © 2005 Wiley‐Liss, Inc.
Nanoscale imaging and quantification of local proteolytic activity
Authors: Kusick Stephan , Bertram Helga , Oberleithner Hans , Ludwig Thomas
Published: March 2005

Proteolytic cleavage of extracellular matrix (ECM) is a critical feature of tumor cell invasion, and affects cancer cell growth, differentiation, apoptosis, and migration. Malignant cells secrete most proteases as inactive proenzymes that undergo proteolytic cleavage for activation, and proteolytic activity is elevated in close proximity to these cells. Therefore, local activity rather than protease concentration determines ECM proteolysis. Precise quantification of local proteolytic activity, functional investigation, and high resolution imaging of morphological ECM alterations have proven difficult. In this study, we present a novel approach for measuring proteolytic activity in the microenvironment of cells by using atomic force microscopy (AFM). Amelanotic melanoma cells (A7‐clone) were seeded on fluorescent gelatin or collagen‐IV coatings. Proteolysis reduced fluorescence of these coatings. Fluorescence microscopy (FM) in combination with AFM was used to maneuver the AFM‐tip to tumor cell induced proteolytic spots. AFM enabled nanoscale volume measurement, three‐dimensional reconstruction of single proteins and demonstrated that ECM cleavage is restricted to the proteolytic microenvironment of cancer cells. This method detected significant decreases in molecular weight of protein clusters (−76.6%), matrix volume (−46.6%), and height (−38.1%) between intact and proteolyzed gelatin. Similar parameter changes were demonstrated without FM, by AFM‐scanning gelatin in close proximity to invasive cells. Furthermore, AFM depicted significantly stronger local degradation of gelatin than collagen‐IV by A7‐cells. Taken together, AFM allows specific quantification and imaging of local proteolytic processes at a nanometer level, thus providing a unique method for the functional evaluation of invasiveness and metastatic potential of tumor cells in small scale samples. © 2005 Wiley‐Liss, Inc.
Oxidative damage is a potential cause of cone cell death in retinitis pigmentosa
Authors: Shen JiKui , Yang Xiaoru , Dong Aling , Petters Robert M. , Peng You‐Wei , Wong Fulton , Campochiaro Peter A.
Published: March 2005

Retinitis pigmentosa (RP) is a prevalent cause of blindness caused by a large number of different mutations in many different genes. The mutations result in rod photoreceptor cell death, but it is unknown why cones die. In this study, we tested the hypothesis that cones die from oxidative damage by performing immunohistochemical staining for biomarkers of oxidative damage in a transgenic pig model of RP. The presence of acrolein‐ and 4‐hydroxynonenal‐adducts on proteins is a specific indicator that lipid peroxidation has occurred, and there was strong immunofluorescent staining for both in cone inner segments (IS) of two 10‐month‐old transgenic pigs in which almost all rods had died, compared to faint staining in two 10‐month‐old control pig retinas. In 22‐ and 24‐month‐old transgenic pigs in which all rods and many cones had died, staining was strong in cone axons and some cell bodies as well as IS indicating progression in oxidative damage between 10 and 22 months. Biomarkers for oxidative damage to proteins and DNA also showed progressive oxidative damage to those macromolecules in cones during the course of RP. These data support the hypothesis that the death of rods results in decreased oxygen consumption and hyperoxia in the outer retina resulting in gradual cone cell death from oxidative damage. This hypothesis has important therapeutic implications and deserves rapid evaluation. © 2005 Wiley‐Liss, Inc.
Drop size distribution in highly concentrated liquid–liquid dispersions using a light back scattering method
Authors: Lovick J , Mouza AA , Paras SV , Lye GJ , Angeli P
Published: March 2005

New data are presented on drop size distribution at high dispersed phase fractions of organic‐in‐water mixtures, obtained with a light back scattering technique (3 Dimensional Optical Reflectance Measurement technique, 3D ORM). The 3D ORM technique, which provides fast, in‐situ and on‐line drop distribution measurements even at high concentrations of the dispersed phase, is validated using an endoscope attached to a high‐speed video recorder. The two techniques compared favourably when used in a dispersion of oil (density (ρ) = 828 kg m−3, viscosity (µ) = 5.5 mPa s, interfacial tension (σi) = 44.7 mN m−1) in water for a range of 5–10% dispersed phase fractions. Data obtained with the ORM instrument for dispersed phase fractions up to 60% and impeller speeds 350–550 rpm showed a decrease in the maximum and the Sauter mean drop diameters with increasing impeller speed. Phase fractions did not seem to significantly affect drop size. Both techniques showed that drop size distributions could be fitted by the log‐normal distribution. Copyright © 2005 Society of Chemical Industry
Electrochemical treatment of diluted cyanide aqueous wastes
Authors: Cañizares Pablo , Díaz Marly , Domínguez Jorge A , Lobato Justo , Rodrigo Manuel A
Published: March 2005

The electrochemical oxidation of diluted cyanide aqueous wastes has been studied in a single compartment electrochemical flow cell. It has been determined that the anode material influences greatly the process's performance. Boron doped diamond and PbO2 anodes can oxidize these wastes in the presence of both sulfate or chloride anions. On the contrary, dimensional stable anodes cannot oxidize cyanide in sulfate‐containing wastewaters, and require the presence of chloride ions. The oxidation of cyanides leads to the formation of cyanate in a first step, and later to the formation of carbon dioxide and nitrogen. There is a net consumption of hydroxyl ions during the process. Energy consumptions in the range 20–70 kWh m−3 are required to decrease the initial pollutant load by 70–80%. Global current efficiencies in the range 3–8% are obtained. These low current efficiencies are justified by the low cyanide concentrations that the wastes used in this work contain. Copyright © 2005 Society of Chemical Industry
Microbial degradation of the detoxification products of mustard from the Russian chemical weapons stockpile
Authors: Ermakova Inna T , Safrina Natalya S , Starovoitov Ivan I , Lyubun Yelena V , Shcherbakov Alexander A , Makarov Oleg E , Kosterin Paul V , Boronin Alexander M
Published: March 2005

This work was undertaken to examine the possibility of biodegradation of the organic components of the ‘reaction masses’ (detoxification products) generated by destruction of the chemical warfare agent mustard. The composition of these components was analysed by gas chromatography and mass spectrometry. The major components formed during chemical detoxification were identified as 1,4‐perhydrothiazine derivatives. N‐(2‐Hydroxyethyl)‐2‐methyl‐1,4‐perhydrothiazine hydrochloride and N‐(2‐hydroxyethyl)‐3‐methyl‐1,4‐perhydrothiazine hydrochloride were predominant (about 70% of total 1,4‐perhydrothiazine derivatives). Pseudomonas putida strains that used some organic components of the mustard reaction masses as carbon sources for growth were isolated and selected. Growth cessation in this medium (with organic carbon still available) was due to the depletion of bioutilisable substrates, primarily monoethanolamine and ethylene glycol (the residual components of the detoxifying mixture). 1,4‐Perhydrothiazine derivatives were not used as carbon sources for growth of P putida strain SH1, but their concentration decreased during bacterial growth with monoethanolamine and ethylene glycol as the carbon substrates. It is suggested that 1,4‐perhydrothiazines undergo transformation by the microbial cells under these conditions. Copyright © 2005 Society of Chemical Industry
A new synthetic biofiltration material: poly(vinyl alcohol)/pig manure compost composite beads
Authors: Chan Wu‐Chung , Zheng Rui‐Xiang
Published: March 2005

Poly(vinyl alcohol) (PVA)/pig manure compost composite beads proved suitable as a biofilter material in a biofiltration process. The composite bead is a porous spherical particle with a diameter between 2.4 and 6.0 mm and a density of 0.96 g cm−3. It contains 9.43 mg P g−1 dry solid and 12.1 mg N g−1 dry solid. The equilibrium moisture contents of the PVA/compost composite beads bed for adsorption and holding experiments are 50.5% and 54.6% by wet basis, respectively, which correspond to the optimal filter material required and could sustain the biological activity. The PVA/pig manure compost composite beads bed has higher moisture‐holding capacity and compression strength than the pig manure compost bed. The PVA/compost composite beads have buffer capacity and could keep the filter bed at pH 6.9–7.2 during operating. The percentage of ethyl acetate removed could stay at over 99% for 40 days of operation as the PVA/pig manure compost composite beads adsorbed inorganic nitrate nutrient. The maximum elimination capacity of the PVA/pig manure compost composite beads filters at the loading rate of 0.71 kg ethyl acetate m−3‐bed h−1 is 0.71 kg ethyl acetate m−3‐bed h−1. Copyright © 2005 Society of Chemical Industry
Treatment of low turbidity water by sweep coagulation using bentonite
Authors: Shen Yun‐Hwei
Published: March 2005

A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na+‐saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm−3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face‐to‐face interactions of platelets and effectively entrapped TiO2 particles in band‐type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO2 particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry
Microbial uptake of diesel oil sorbed on soil and oil spill clean‐up sorbents
Authors: Biswas Subhasis , Chaudhari Sanjeev K , Mukherji Suparna
Published: March 2005

Sorbent effects in the microbial uptake of diesel oil were determined for black cotton soil (BCS) and two oil spill clean‐up sorbents, ie peat sorb and spill sorb. Biodegradation studies were conducted in mass transfer limited batch slurry microcosms using microorganisms capable of direct interfacial uptake of diesel oil. Under identical loading conditions, the amounts of diesel oil initially loaded on the various sorbents were 178, 288 and 649 mg g−1 for BCS, spill sorb and peat sorb, respectively. Total biodegradation of sorbed diesel was comparable for all the sorbents (45–52 mg), however, the biodegradation rates were significantly different. Peat sorb demonstrated a distinct initial lag phase, the biodegradation rate in spill sorb was initially slower, whereas biodegradation at a high rate commenced immediately for BCS. The maximum biodegradation rates observed for BCS, spill sorb and peat sorb microcosms were 7.9, 5, and 2.9 mg day−1, respectively. Thus, the maximum biodegradation rate increased as the diesel oil loading decreased. Our results indicate that spill clean‐up sorbents have greater bioavailability limitations compared with soils and this is linked with their significantly higher loading capacity and internal porosity. Copyright © 2005 Society of Chemical Industry