bluuebunny/crossref_metadata_2025 huggingface dataset:
Transplacental drug transfer and frequency of Tk and Hprt lymphocyte mutants and peripheral blood micronuclei in mice treated transplacentally with zidovudine and lamivudine
Authors: Von Tungeln Linda S. , Williams Lee D. , Doerge Daniel R. , Shaddock Joseph G. , McGarrity Lynda J. , Morris Suzanne M. , Mittelstaedt Roberta A. , Heflich Robert H. , Beland Frederick A.
Published: July 2006

In previous studies, we have shown that zidovudine (3′‐azido‐3′‐deoxythymidine; AZT), but not lamivudine [(‐)2′,3′‐dideoxy‐3′‐thiacytidine; 3TC], is genotoxic when administered to neonatal mice, and that 3TC when coadministered with AZT does not alter the responses observed with AZT alone (Von Tungeln et al. [2002] Carcinogenesis 23:1427–1432). We now have investigated the transplacental transfer of these drugs and the induction of mutants and micronuclei in the neonatal offspring. From gestational day 12 until parturition, female C57BL/6N and C57BL/6N/Tk+/− mice, which had been mated to male C3H/HeNMTV mice, were treated daily by gavage with AZT, 3TC, or a combination of AZT and 3TC. In both dams and fetuses, AZT was found at much higher levels than its metabolites, AZT 5′‐glucuronide and 3′‐azido‐3′‐deoxythymidine. In the neonates, AZT and the mixture of AZT and 3TC caused a decrease in the percentage of reticulocytes (RETs) and an increase in the percentage of micronucleated RETs and micronucleated normochromatic erythrocytes. When assessed 3 weeks after birth, AZT and the combination of AZT and 3TC increased the thymidine kinase (Tk) mutant frequency in male mice; at 5 weeks, 3TC increased the Tk mutant frequency in female mice. The increase in Tk mutants in mice treated with AZT and the mixture of AZT and 3TC was associated with loss of the wild‐type (Tk+) allele (loss of heterozygosity; LOH) and a pattern of discontinuous LOH. These data indicate that AZT, 3TC, and the combination of AZT and 3TC are transplacental mutagens and that the increase in mutants resulting from AZT is due mainly to large‐scale genetic alterations. Environ. Mol. Mutagen. 47:, 2006. Published 2006 Wiley‐Liss, Inc.
Bioactive glass nanofiber–collagen nanocomposite as a novel bone regeneration matrix
Authors: Kim Hae‐Won , Song Ju‐Ha , Kim Hyoun‐Ee
Published: July 2006

Nanoscale organized organic–inorganic nanocomposite systems have great potential in the development of biomaterials with advanced properties. Herein, we developed a novel nanocomposite biomaterial consisting of bioactive glass nanofiber (BGNF) and collagen reconstituted fibrous matrix for bone regenerative medicine. A sol–gel derived glass with a bioactive composition (58SiO2· 38CaO·4P2O5) was electrospun to a nanoscale fiber with an average diameter of ∼320 nm. The BGNF was subsequently hybridized with type I collagen, which is the main organic constituent of bone matrix. The BGNF and self‐assembled collagen sol were combined in aqueous solution, and then crosslinked to produce a BGNF‐collagen nanocomposite, in the form of either a thin membrane or a macroporous scaffold, by adopting appropriate processing conditions. The BGNF was observed to be distributed uniformly within the collagen reconstituted nanofibrous matrix. The nanocomposite matrices induced rapid formation of bone‐like apatite minerals on their surfaces when incubated in a simulated body fluid, exhibiting excellent bioactivity in vitro. Osteoblastic cells showed favorable growth on the BGNF‐collagen nanocomposite. In particular, the alkaline phosphatase activity of the cells on the nanocomposite was significantly higher than that on the collagen. This novel BGNF‐collagen nanocomposite is believed to have significant potential in bone regeneration and tissue engineering applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Tissue‐engineered tear secretory system: Functional lacrimal gland acinar cells cultured on matrix protein‐coated substrata
Authors: Selvam Shivaram , Thomas Padmaja B. , Trousdale Melvin D. , Stevenson Douglas , Schechter Joel E. , Mircheff Austin K. , Jacob Jean T. , Smith Ronald E. , Yiu Samuel C.
Published: July 2006

Dry eye is a general term that refers to a myriad of ophthalmic disorders resulting in the inadequate wetting of the corneal surface by the tear film. Dry eyes are typically treated by the application of artificial tears. However, patients with lacrimal insufficiencies such as Stevens‐Johnson syndrome, chemical and thermal injuries, or ocular cicatricial pemphigoid have very limited options because of the short duration and action of lubricating agents. As a therapeutic strategy, we are working to develop a bioengineered tear secretory system for such patients. This article describes the growth and physiological properties of purified rabbit lacrimal gland acinar cells (pLGACs) on several matrix protein‐coated polymers such as silicone, collagen I, copolymers of poly‐D,L‐lactide‐co‐glycolide (PLGA; 85:15 and 50:50), poly‐L‐lactic acid (PLLA), and Thermanox® plastic cell culture coverslips. Monolayers of acinar cells were established on all of the polymeric substrata. An assay of β‐hexosaminidase activity in the supernatant medium showed significant increases in protein secretion, following stimulation with 100 μM carbachol on matrix protein‐coated and uncoated polymers such as silicone, PLGA 85:15, and PLLA. Our study demonstrates that PLLA supported the morphological and physiological properties of purified rabbit lacrimal gland epithelial cells more successfully than the others. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Potential of FeAlCr intermetallics reinforced with nanoparticles as new biomaterials for medical devices
Authors: González‐Carrasco J. L. , Ciapetti G. , Montealegre M. A. , Savarino L. , Muñoz‐Morris M. A. , Baldini N.
Published: July 2006

Novel FeAlCr oxide dispersion strengthened intermetallics that are processed by powder metallurgy have been developed as potential biomaterials. The alloys exhibit a small grain size and a fine dispersion of yttria provides the material with a high yield strength and depending on the alloy composition good ductility (up to 5%). The biocompatibility of the alloy was assessed in comparison with commercial alumina. Saos‐2 osteoblast‐like cells were either challenged with mechanically alloyed particles, or seeded onto solid samples. Viability and proliferation of cells were substantially unaffected by the presence of a high concentration of particles (1 mg/mL). Solid samples of novel FeAlCr intermetallic have shown a good biocompatibility in vitro, often approaching the behavior of materials well known for their biological acceptance (e.g. alumina). It has been found that osteoblasts are able to produce ALP, a specific marker of cells with bone‐forming activity. In this respect, ALUSI alloys hold the promise to be suitable substrate for bone integration. The finding of no cytotoxic effect in the presence of the alloy particles is a reliable proof of the absence of acute toxicity of the material. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Bacterial inactivation using a low‐temperature atmospheric plasma brush sustained with argon gas
Authors: Yu Q. S. , Huang C. , Hsieh F.‐H. , Huff H. , Duan Yixiang
Published: July 2006

This study investigated the bacterial inactivation/sterilization effects of a new atmospheric plasma source, which is a brush‐shaped argon glow discharge created under 1 atm pressure. Such an atmospheric plasma brush requires extremely low power of less than 20 W to operate; and therefore is essentially a low‐temperature discharge as confirmed by gas‐phase temperature measurements. Two bacteria,Escherichia coli(E. coli) andMicrococcus luteus(M. luteus), seeded in various media were subjected to plasma treatment and their survivability was examined. It was found that such argon atmospheric plasma brush is very effective in destruction of the bacteria cells. With nutrient broth and standard methods agar as supporting media, a cell reduction in a level of 6 orders of magnitude was observed forE. coliwithin 3–4 min plasma treatment. A similar level of cell reduction was also observed forM. luteusin the two media with 2 or 3 min plasma treatment. The plasma treatment effects on the bacteria cell structures were also examined using scanning electron microscopy and the cell structure damages due to the plasma exposure were observed on both bacteria. The possible sterilization mechanism of the argon plasmas is also discussed in this article. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18‐month follow‐up study
Authors: Kang Sun‐Woong , Cho Eui Ri , Jeon Oju , Kim Byung‐Soo
Published: July 2006

The injection of bulking substances has been proposed as a new therapy to treat urinary incontinence and vesicoureteral reflux. Our previous study demonstrated that poly(lactic‐co‐glycolic acid) (PLGA) microspheres have the potential to serve as a bulking agent for urological injection therapies. Hybrid tissues exhibiting a bulking effect were formed in vivo by PLGA microsphere injection, but long‐term volume stability was not proven. In this study, we hypothesized that the biodegradation rate of the bulking substance (polymer microspheres) would affect the duration of volume conservation of the induced hybrid tissue. To test this hypothesis, rapidly degrading 75:25 PLGA microspheres and slowly degrading poly(L‐lactic acid) (PLLA) microspheres were used as injectable bulking agents for the injection therapy. In vitro degradation tests showed that the mass losses of PLLA and PLGA were 16 and 96% of the initial masses, respectively, at 30 weeks. PLLA and PLGA microspheres were injected into the subcutaneous dorsum of mice. Both types of microspheres were easily injectable through 24‐gauge needles. Histological examinations at various time points indicated that host cells from the surrounding tissues migrated to the spaces between both types of injected microspheres and formed new hybrid tissue structures. Lymphocyte migration was noted around the implanted PLGA and PLLA microspheres, but the inflammatory reaction diminished with time. Importantly, the volume of the PLLA hybrid tissues slowly decreased to 52% of the initial volume at 12 months and maintained that volume until 18 months, whereas the volume of the PLGA hybrid tissues rapidly decreased to 22% at 6 months, and the PLGA hybrid tissues disappeared at 11 months. These results show that the biodegradation rate of the bulking substance may be useful for controlling the duration of volume conservation of the induced hybrid tissue. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Formation of bone‐like apatite enhanced by hydrolysis of octacalcium phosphate crystals deposited in collagen matrix
Authors: Honda Y. , Kamakura S. , Sasaki K. , Suzuki O.
Published: July 2006

It has been shown that granules of synthetic octacalcium phosphate (OCP) or the composites with collagen are capable of enhancing bone regeneration, accompanied by a gradual conversion from OCP to apatite with time. The present study was designed to investigate whether formation of bone‐like apatite can be accelerated by OCP deposited throughout collagen matrix (OCP collagen complex, OCC) immersed in simulated body fluid (SBF). The formation of bone‐like apatite has been suggested to be essential to induce osteoconductivity of various substrates. The formation of OCP in collagen solution was investigated in calcium or phosphate ions in the range between 22.5 and 142.5 mM and pH 6.26 and 8.56. X‐ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) showed that condition to nucleate OCP was limited to that of a solution with Ca/P 0.43 around pH 7.16 in the presence of collagen. OCP was shown to be formed throughout the collagen matrix by SEM observation. The immersion of OCC in SBF up to 10 days enhanced apatite crystal deposition, probably through OCP–apatite conversion: the apatite formation in OCC took place within only 1 day. The present study indicated that the existence of OCP deposited throughout the collagen matrix promotes bone‐like apatite formation under physiological condition. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Biocompatibility of a new radiopaque iodine‐containing acrylic bone cement
Authors: van Hooy‐Corstjens Catharina S. J. , Bulstra Sjoerd K. , Knetsch Menno L. W. , Geusens Piet , Kuijer Roel , Koole Leo H.
Published: July 2006

Radiopacity in the vast majority of the commercially available acrylic bone cements that are used clinically is provided by particles of either BaSO4 or ZrO2. Literature reports have shown these agents to have a detrimental effect on some mechanical properties of the cements as well as on its biological response. We, therefore, have developed a new type of bone cement, for which radiopacity results from the presence of an iodine‐containing methacrylic copolymer. The focus of the present work was the comparison of the biocompatibility of this new cement and a commercially available cement that contains barium sulfate. In vitro experiments show that both cements are cytocompatible materials, for which no toxic leachables are found. Implantation of the cements in a rabbit for three months resulted in the occasional presence of a thin fibrous tissue at the cement–bone interface, which is common for acrylic bone cements. Consideration of all the results led to the conclusion that the new cement is as biocompatible as the BaSO4‐containing one. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Photocatalytic antibacterial effect of TiO2 film formed on Ti and TiAg exposed to Lactobacillus acidophilus
Authors: Choi Jung‐Yoon , Kim Kyung‐Ho , Choy Kwang‐Chul , Oh Keun‐Taek , Kim Kyoung‐Nam
Published: July 2006

When irradiated under near‐ultraviolet (UV) light, TiO2 exhibits strong bactericidal activity. The TiO2 photocatalyst would be effective on orthodontic appliances after its antibacterial effect on the carcinogenic microorganism Lactobacillus acidophilus is evaluated. To compare the antibacterial effect of two crystalline forms of TiO2, rutile and anatase, thermal oxidation and anodic oxidation were employed to form each structure, respectively. The antibacterial effect of TiO2 film on TiAg was also compared with that on Ti. Bacterial solutions were pipetted onto the TiO2‐coated specimen and illuminated with UVA (2 × 15 W, black light, 356 nm) up to 100 min and the reaction solutions were incubated to count the colony‐forming units. The antibacterial activity of the coated specimens was similar to that of the uncoated group. The antibacterial activity of the coated specimens of TiAg was not different from that of Ti. TiO2 coatings formed on both Ti and TiAg specimens did not exhibit cytotoxicity on the L‐929 cells of mice. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Finite element analysis of a transmandibular implant
Authors: Nomura Tsutomu , Powers Michael P. , Katz J. Lawrence , Saito Chikara
Published: July 2006

Finite element analysis (FEA) was used to study the influence of bony height and baseplate effect on the transmandibular implant (TMI). FEA was used to assess the stress distribution in the mandible, with and without a baseplate. Forces were applied to the center of a bar space. The von Mises stress (SEQV) was displayed in bone, and shear stress also was measured. Tensile stress was always seen at the so‐called saddle area; compressive stress was seen at the inferior border. Tensile strain at the saddle area of a 6‐mm height mandible is always 9.1 times greater (corresponding to more SEQV) than that of an 18‐mm mandible. At same bone heights, saddle area stresses are similar with or without a baseplate. However, stress at the lateral transossseous post interface with bone was significantly different between different bone height groups. Shear stress around the lateral transossseous post was smaller than does the SEQV of the same site. Decreased bone height dramatically increases stress at the saddle area independent of the baseplate presence. These data suggest that bone apposition is found in the severely atrophic mandibles. Thus, there is no need for a baseplate in a slight to mild atrophic mandible. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Influence of implant surface topography on early osseointegration: A histological study in human jaws
Authors: Shibli Jamil Awad , Grassi Sauro , Cristina de Figueiredo Luciene , Feres Magda , Marcantonio Elcio , Iezzi Giovanna , Piattelli Adriano
Published: July 2006

The purpose of this study was to evaluate the influence of the oxidized surface on bone‐to‐implant contact (BIC%), the bone density in the threaded area (BA%), as well as the bone density outside the threaded area (BD%) in human jaws after 2 months of unloaded healing. Thirteen subjects (mean age 42.61 ± 6.15 years) received two microimplants (2.5 mm diameter and 6 mm length) each, during conventional mandible or maxilla implant surgery. The microimplants with commercially pure titanium surfaces (machined) and oxidized surfaces served as the control and test surfaces, respectively. After 2 months, the microimplants and the surrounding tissue were removed and prepared for histomorphometric analysis. All microimplants, except two machined and one oxidized microimplant surfaces, were found to be clinically stable after the healing period. Histometric evaluation indicated that the mean BIC% was (21.71 ± 13.11)% and (39.04 ± 15.75)% for machined and oxidized microimplant surfaces, respectively. The BD% was higher for the oxidized surface, although there was no difference for maxilla and mandible. The oxidized surface impacted the BA% for the type‐IV bone. Data suggest that the oxidized surface presented a higher bone‐to‐implant contact rate compared with machined surfaces under unloaded conditions, after a healing period of 2 months. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Polyethylene glycol‐based cationically charged hydrogel beads as a new microcarrier for cell culture
Authors: Cer Esra , Gürpınar Özer Aylin , Onur Mehmet A. , Tuncel Ali
Published: July 2006

A new polyethylene glycol (PEG) based microcarrier was designed and examined by the attachment and growth of mouse fibroblast cells. In the design of microcarrier, a PEG‐based macromonomer, polyethyleneglycol methacrylate (PEGMA), was selected as the main component of hydrogel beads since PEG is known as a nontoxic and biocompatible material. A relatively new cationic comonomer, N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPM), with higher ionization ability with respect to the similar comonomers was used for providing cationic charge to the hydrogel structure. In the first part, a suspension copolymerization method was developed for the production of cationically charged hydrogel beads as a potential microcarrier for cell culturing. The suspension copolymerization by using ethylene dimethacrylate (EDM) as cross‐linking agent and cyclohexanol as the diluent provided spherical, polydisperse poly(PEGMA‐DMAPM‐EDM) hydrogel beads with an average size of 121 μm. The hydrogel beads exhibited a pH‐dependent swelling behavior. The L929 mouse fibroblast cells were cultured on poly(PEGMA‐DMAPM‐EDM) hydrogel beads with an initial concentration of 200,000 cells/mL. The cells were incubated in Dulbecco's modified Eagle's medium during 5 days and the cell proliferation was investigated at every 24 h. An effective cell attachment and growth up to 3.5 × 106 cells/mL were observed with the poly(PEGMA‐DMAPM‐EDM) hydrogel beads. The results indicated that the proposed microcarrier was a significant alternative to the hydrogel beads obtained by the copolymerization of 2‐hydroxyethyl methacrylate and 2‐dimethylaminoethylmethacrylate commonly used in microcarrier‐facilitated cell culturing studies. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
A general efficient implementation of the BSSE‐free SCF and MP2 methods based on the chemical Hamiltonian approach
Authors: Salvador P. , Asturiol D. , Mayer I.
Published: July 2006

We describe some details related to a new, general, and efficient implementation of the BSSE‐free SCF and second‐order Møller–Plesset perturbation theories of intermolecular interactions, based on the “Chemical Hamiltonian Approach” (CHA). The program is applicable for both open‐shell and closed‐shell systems and for an arbitrary number of interacting subsystems. With the new program the CHA method is faster than the usual “counterpoise correction” scheme for single point calculations, especially for clusters consisting of several molecules. The numerical results provided by these conceptually different schemes, however, have again found to be very close to each other. The CHA scheme is particularly good for providing truly BSSE‐free MP2 data for intermolecular potentials. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1505–1516, 2006
Removal of organic xenobiotics in activated sludges under aerobic conditions and anaerobic digestion of the adsorbed species
Authors: Dionisi Davide , Bertin Lorenzo , Bornoroni Lorena , Capodicasa Serena , Papini Marco Petrangeli , Fava Fabio
Published: July 2006

The abiotic and biotic fate in activated sludge plants of a mixture of aromatic pollutants including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, chlorinated and non‐chlorinated benzenes, phenols and surfactants was studied. To this aim, an activated sludge collected from a municipal plant was artificially spiked with the target compounds. Under aerobic conditions, adsorption and biodegradation were distinguished as possible mechanisms of target compound removal through comparison of tests with and without oxygen. With the exception of phenol, which was completely biodegraded (at an average rate of 2.6 mg phenol g−1 volatile suspended solids h−1), the pollutants were completely or significantly removed from the liquid phase through adsorption. In the tested conditions the amount of substance removed through adsorption ranged from 75–80% for 4‐dodecylbenzenesulfonic acid and pentachlorophenol to more than 90% for the other compounds. Kinetic and equilibrium parameters describing the adsorption of the different xenobiotics to the sludge were also determined. The role of anaerobic digestion in the final decontamination of the xenobiotic‐containing sludge was evaluated under mesophilic and thermophilic conditions. A significant average depletion of the chlorinated pollutants was observed in mesophilic conditions (24.6%). The addition of yeast extract stimulated the process by allowing a higher chlorinated pollutant average depletion (49.7%) and complete disinfection of the sludge. Copyright © 2006 Society of Chemical Industry
Influence of hydrogen on the reductive dechlorination of tetrachloroethene (PCE) to ethene in a methanogenic biofilm reactor: role of mass transport phenomena
Authors: Aulenta Federico , Di Tomassi Claudio , Cupo Cinzia , Petrangeli Papini Marco , Majone Mauro
Published: July 2006

This study investigated the influence of H2 bulk liquid concentration in the range 2–120 µmol L−1 on the kinetics of vinyl chloride (VC) formation from tetrachloroethene (PCE) and VC dechlorination to ethene in a methanogenic biofilm reactor containing Dehalococcoides spp. as the putative dechlorinating micro‐organism. Both VC formation and dechlorination showed a definite increase in rate with increasing H2 bulk liquid concentration, following a pattern typical of Michaelis–Menten kinetics. The estimated maximum VC formation rate (81.7 ± 9.4 µmol L−1 h−1; mean value ± 90% confidence interval) was about ten times higher than the estimated maximum VC dechlorination rate (8.2 ± 1.0 µmol L−1 h−1), while the estimated apparent half‐velocity coefficient for H2 for VC formation (1.5 ± 1.4 µmol H2 L−1) was more than six times lower than that for VC dechlorination (9.1 ± 5.1 µmol H2 L−1), confirming that the last step of PCE dechlorination (i.e. conversion of VC to ethene) was much more H2‐sensitive than the previous ones. The estimated maximum methane formation rate was 462.1 ± 213.5 µmol L−1 h−1 and the estimated apparent half‐velocity coefficient was 104.7 ± 89.4 µmol H2 L−1. Experiments at different temperatures indicated the presence of severe internal (diffusional) mass transfer limitations and, in turn, of steep H2 concentration gradients through the biofilm, which strongly influenced the estimated apparent half‐velocity coefficients for H2 use. The results of this study emphasise the importance of considering mass transfer phenomena when predicting the rate of PCE dechlorination and the outcome of competition for H2 in natural or engineered bioremediation systems. Copyright © 2006 Society of Chemical Industry
Biodegradation of 2‐fluorobenzoate in upflow fixed bed bioreactors operated with different growth support materials
Authors: Emanuelsson Maria AE , Henriques Isabel S , Ferreira Jorge Ruben M , Castro Paula ML
Published: July 2006

Three upflow fixed bed bioreactors treating an aqueous stream containing 2‐fluorobenzoate were operated for a period of 7 months, during which they were exposed to high organic loading rates and starvation. The reactors contained granular activated carbon (GAC), polyethylene (PE) particles and expanded clay (EC) respectively as growth support for microbial biofilms. The performance of the reactors was compared and the biofilm microbial population was followed by cell counting and denaturing gradient gel electrophoresis (DGGE). The reactor containing GAC always had 100% removal efficiency owing to the adsorption properties of the material combined with biodegradation. The GAC reactor also recovered better after starvation periods in the sense that it showed more stable behaviour than the reactors containing EC and PE. The highest biological elimination capacity was observed for the reactor containing EC, which reached 200 mg day−1 L−1 during reactor start‐up, but during long‐term operation the reactor containing GAC showed the highest biological elimination capacity, 140 mg day−1 L−1. DGGE analysis indicated that starvation periods seemed to be responsible for shifts in the microbial population. Copyright © 2006 Society of Chemical Industry
A flow injection analysis system for on‐line monitoring of cutinase activity at outlet of an expanded bed adsorption column almost in real time
Authors: Almeida Claudio F , Calado Cecília RC , Bernardino Susana A , Cabral Joaquim MS , Fonseca Luis P
Published: July 2006

Expanded bed adsorption (EBA) was used to recover, concentrate and purify Fusarium solani pisi cutinase, secreted by a recombinant Saccharomyces cerevisiae strain, directly from a whole fermentation culture. A flow injection analysis (FIA) system for monitoring Fusarium solani pisi cutinase based on microencapsulation of p‐nitrophenylbutyrate (p‐NPB) in a micellar system (sodium cholate, tetrahydrofuran, phosphate buffer) was developed for monitoring this target enzyme at the outlet tube of the EBA column. Slight differences in yeast cultivation conditions during cutinase production may influence the fermentation performance, which affects directly the adsorption of cutinase during the loading step and consequently the efficiency of the EBA process. This effect can be especially relevant when it is necessary to stop the application of feedstock to the EBA column when the outlet concentration (A) of the desired product is lower than 5% of the feed concentration (Ao). Excellent correlations between the FIA system and the off‐line analytical method for monitoring cutinase activity during the different EBA steps were obtained. Additionally, the blocking/fouling of the sample injector and tubes of the FIA system initially observed were eliminated due to the excellent surfactant properties of the sodium cholate contained in the phosphate buffer and used to dilute the enzyme samples. This FIA system was shown to be a powerful analytical tool for monitoring cutinase activity almost in real time (45–60 s), maximizing enzyme adsorption while minimizing product loss and consequently maximizing the recovery yield of the product. Copyright © 2006 Society of Chemical Industry
Organic acids: old metabolites, new themes
Authors: Goldberg Israel , Rokem J Stefan , Pines Ophry
Published: July 2006

Fumaric, L‐malic and citric acids are intermediates of the oxidative tricarboxylic acid (TCA) cycle which in eukaryotes is localized in mitochondria. These organic acids are synthesized and accumulated in the medium to very high concentrations by filamentous fungi such as Aspergillus spp. and Rhizopus sp. This article reviews basic research on the unusual acid production capability and the associated metabolic pathways operating under defined stress conditions in these specific fungi. In particular, we describe and discuss the importance of the cytosolic reductive TCA pathway, which includes the cytosolic activities of pyruvate carboxylase, malate dehydrogenase and fumarase, for production of fumaric and L‐malic acids. This article also describes the differences between fumaric acid, L‐malic acid and citric acid production by different organisms (filamentous fungi, yeast, and higher eukaryotes), and the possible application of novel technologies (genetic engineering and bioinformatics) to fungal systems which may offer new industrial potential of filamentous fungi for the production of valuable metabolites. Copyright © 2006 Society of Chemical Industry
HIV replication elicits little cytopathic effects in vivo: Analysis of surrogate markers for virus production, cytotoxic T cell response and infected cell death
Authors: Funk Georg A. , Oxenius Annette , Fischer Marek , Opravil Milos , Joos Beda , Flepp Markus , Weber Rainer , Günthard Huldrych F. , Bonhoeffer Sebastian
Published: July 2006

Several potential mechanisms for viral destruction of HIV‐infected cells have been described. The hypothesis was examined that if HIV were cytopathic, a positive relation between the in vivo virus production or CTL activity and infected cell death should be observed. In a regression analysis no significant relation was found between surrogate markers for in vivo virus production or the virus‐specific CTL response and death rates of productively infected cells. In a subgroup of patients the hypothesis is rejected that HIV replication elicits a large (R2 > 0.25) cytopathic effect (P < 0.05, N = 36). It is concluded that HIV replication elicits little cytopathic effect in productively infected cells and that CD4+ T lymphocytes are eroded by other mechanisms. J. Med. Virol. 78:1141–1146, 2006. © 2006 Wiley‐Liss, Inc.
Interleukin‐2 reconstitutes defective human immunodeficiency virus (HIV), and cytomegalovirus (CMV) specific CD8+ T cell proliferation in HIV infection
Authors: Yu Jie , Chen Huiyuan , Horton Helen , Bansal Anju , McElrath Julie M. , Reichman Richard , Goepfert Paul , Jin Xia
Published: July 2006

Recent studies indicate that a defective proliferative response of HIV‐specific CD8+ T cells is associated with the lack of virologic control in chronic HIV infection in humans. The possible mechanisms that might be responsible for the reduced proliferative potential of HIV‐specific CD8+ T cells and conditions conducive to the proliferation of CD8+ T cells were examined in 14 HIV‐infected individuals and 7 HIV‐uninfected controls using CFSE labeling and flow cytometry techniques, and analyzed data using 2 quantitative measurements: the percentages of proliferating CD8+ T cells (Tp), and the maximum number of cell divisions (Dm) after stimulation. It was found that CD8+ T cells from HIV‐infected and ‐uninfected subjects proliferated equally well after polyclonal stimulation by phylohemagglutinin A (PHA); both groups reached a Tp of 92%–96% and a Dm of 5–8. However, in HIV‐infected subjects, proliferation of HIV‐ and CMV‐specific CD8+ T cells was significantly reduced compared to proliferation of CMV‐ specific CD8+ T cells from HIV‐uninfected subjects. These defective proliferative responses of HIV‐ and CMV‐specific CD8+ T cells were restored by the addition of IL‐2 at the time of stimulation. These results may have implications for the design of immune modulation strategies in vivo. J. Med. Virol. 78:1147–1157, 2006. © 2006 Wiley‐Liss, Inc.
HCV‐related morbidity in a rural community of Egypt
Authors: Mohamed Mostafa K. , Bakr Iman , El‐Hoseiny Mostafa , Arafa Naglaa , Hassan Abubakr , Ismail Soheir , Anwar Mohamed , Attala Mohamed , Rekacewicz Claire , Zalata Khaled , Abdel‐Hamid Mohamed , Esmat Gamal , Fontanet Arnaud
Published: July 2006

The origin of the hepatitis C virus (HCV) epidemic in Egypt has been attributed to intravenous schistosomiasis treatment in rural areas in the 1960s to 70s. The objective of this study was to estimate the HCV‐related morbidity in a rural area where mass schistosomiasis treatment campaigns took place 20–40 years before. The study sample included 2,425 village residents aged 18–65 years recruited through home‐based visits. Overall, HCV antibody prevalence was 448/2,425 = 18.5% (95% CI = 16.9–20.1%), reaching 45% in males over 40 years, and 30% in females over 50 years. Of those with HCV antibodies, 284/448 (63.4%, 95% CI = 58.7–67.9%) had chronic HCV infection, among which 107/266 (40.2%, 95% CI = 34.3–46.4%) had elevated alanine aminotransferase (ALT). As part of pre‐treatment screening, 26 consenting patients had a liver biopsy: 13 (50.0%) had a treatment indication. Thus, of all patients with HCV antibodies, 13 (2.9%) were eligible for treatment and willing to be treated. The relatively low level of morbidity observed in this study is discussed in view of co‐factors of HCV infection progression, such as young age at infection, absence of alcohol intake, the prevalence ofSchistosoma mansoniinfection, and the prevalence of chronic hepatitis B. J. Med. Virol. 78:1185–1189, 2006. © 2006 Wiley‐Liss, Inc.
An outbreak of influenza in a residential drug‐rehabilitation community
Authors: Boschini Antonio , Longo Benedetta , Caselli Francesca , Begnini Marco , De Maria Cesare , Ansaldi Filippo , Durando Paolo , Icardi Giancarlo , Rezza Giovanni
Published: July 2006

Influenza outbreaks can be difficult to control in confined settings where high‐risk individuals are concentrated. Following the occurrence of a large number of cases of influenza‐like illness in a rehabilitation community for drug users, between February and March 2004, surveillance activities were implemented. Attack rates of influenza‐like illness were calculated, and risk factors for the development of disease and complications were evaluated through the use of relative risks (RR) with 95% confidence intervals (CI). Nasal‐pharyngeal samples were collected for virological studies. Of 1,310 persons who were living in the community, 209 were diagnosed with influenza‐like illness: the attack rate (15.9% overall) was higher for HIV‐infected persons (RR: 1.77, 95% CI: 1.32–2.37), older individuals, and dormitory residents. HIV‐infected participants were also more likely to develop complications compared with HIV‐uninfected persons diagnosed with influenza‐like illness (RR: 5.13, 95% CI: 2.52–10.20). The outbreak was attributable to Christchurch‐like influenza A strains. Vaccination was ineffective because of the mismatch between wild and vaccine strains. J. Med. Virol. 78:1218–1222, 2006. © 2006 Wiley‐Liss, Inc.
Detection of human metapneumovirus in respiratory secretions by reverse‐transcriptase polymerase chain reaction, indirect immunofluorescence, and virus isolation in human bronchial epithelial cells
Authors: Ingram R.E. , Fenwick F. , McGuckin R. , Tefari A. , Taylor C. , Toms G.L.
Published: July 2006

Over two winters in Newcastle upon Tyne, respiratory secretions, negative by immunofluorescence staining for other respiratory viruses, were tested for the presence of human metapneumovirus (HMPV) by RT‐PCR. In the second winter, specimens were also tested by immunofluorescence staining with an anti‐HMPV polyclonal rabbit antiserum and immunofluorescence positive specimens were inoculated into a line of human bronchiolar cells, 16HBE140. Overall, 55 of 549 (10%) specimens tested were positive for HMPV by RT‐PCR. Of 162 specimens tested by both RT/PCR and immunofluorescence staining, 23 were positive by both techniques. Of five specimens positive by RT‐PCR alone, only one was confirmed with a second set of primers. Of three specimens positive by immunofluorescence alone, only one was confirmed by virus culture. All four previously recognized sub‐genotypes of the virus were identified by both RT‐PCR and immunofluorescence staining. Sub‐genotype A1 was prevalent in the first winter and B1 prevalent in the second. HMPV replication and virus isolation rates were higher in 16HBE140 cells than in monkey kidney cells and did not require exogenous trypsin. Low passage isolates of both sub‐genotypes A2 and B1 replicated slowly reaching peak titers only 12 days after inoculation. In summary, single round RT/PCR and immunofluorescence staining with a polyclonal rabbit antiserum proved of equal sensitivity in the diagnosis of HMPV infection in respiratory secretions both detecting 96% of confirmed positive specimens. 16HBE40 cells provided a significant improvement on monkey kidney cells for the isolation and propagation of the virus. J. Med. Virol. 78:1223–1231, 2006. © 2006 Wiley‐Liss, Inc.
Morphology and Conformation Analysis of Self‐Assembled Triblock Copolymer Melts
Authors: Abu‐Sharkh Basel , AlSunaidi Abdullah
Published: July 2006

Summary: We used the dissipative particle dynamics method to simulate the self‐assembly of symmetric triblock copolymers of the type ABA. Depending on the volume fraction of the end blocks fA, several mesophases including lamellar, perforated lamellar, gyroid, hexagonal cylinders and bcc spherical micelles were obtained. The order‐disorder transition (ODT) at fA = 0.5 was found to be about χN = 19.8. The ODT for the cylindrical mesophase at symmetrical points on the phase diagram had different values, indicating asymmetry in the phase diagram. We were also able to estimate the bridge fraction in the different mesophases. They range from about 0.44 for the lamellar mesophase to about 0.75 for the spherical micelles. Our simulation results are in good agreement with previously reported theoretical calculations and experimental observations.

The hexagonal cylinders generated with the A6B4A6 copolymer.

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The hexagonal cylinders generated with the A6B4A6 copolymer.
Selection of Catalyst for the Esterification Step of the PPT Polymerization Process
Authors: Mitra Kishalay , Majumdar Saptarshi
Published: July 2006

Summary: TBOT is a proven catalyst for the esterification step of the PPT polymerization process. Previous studies have shown that the performance of TBOT is superior in terms of the enhanced degree of polymerization and shorter processing time. However, one interesting aspect which has not yet been investigated is whether with different process objectives, like by‐product minimization and controlled growth of desired functional groups, any other catalyst offers any increase in process performance. The present study gives a detailed process analysis through different sets of optimized operations, which consists basically of searching for other catalytic options for process improvements. A well validated kinetic model for the esterification step of the PPT polymerization process and the advanced Real‐Coded NSGA‐II optimization routine have been used in this study. It can be seen that with all the process considerations, such as maximization of the degree of polymerization, minimization of processing time and the enhanced controlled growth of desired functional groups and minimization of by‐products, the Zn‐based catalyst can replace the conventional Ti‐based catalyst. An Sn‐based catalyst was also found to be able to compete with these two catalysts in some cases.

Optimized Pareto plot for a study on the 4 objectives case for various catalysts. The Zn‐based catalyst outperforms the others.

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Optimized Pareto plot for a study on the 4 objectives case for various catalysts. The Zn‐based catalyst outperforms the others.
HPLC quantification of alkaloids from Haplophyllum extracts and comparison with their cytotoxic properties
Authors: Fiot Julien , Jansen Olivia , Akhmedjanova Valentina , Angenot Luc , Balansard Guy , Ollivier Evelyne
Published: July 2006

An efficient system for the analysis of total alkaloids extracted from the aerial parts from different species of genus Haplophyllum (Rutaceae) by HPLC on a reversed‐phase column is described. The HPLC method described was validated for its specificity, linearity and precision using external standards (haplopine, skimmianine and haplamine). The chromatographic conditions allowed the separation of alkaloids and the quantification of haplopine, skimmianine and haplamine in different samples of species of Haplophyllum collected in Uzbekistan. The alkaloidal contents of samples were compared with their in vitro cytotoxic properties against two cancer cell lines (HeLa and HCT‐116). The cytotoxicity of extracts was correlated with the concentration of haplopine, skimmianine or haplamine in aerial parts of species of Haplophyllum. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of the defence phosphoproteome of Arabidopsis thaliana using differential mass tagging
Authors: Jones Alexandra M. E. , Bennett Mark H. , Mansfield John W. , Grant Murray
Published: July 2006

Despite recent advances in proteomic technologies, quantitative analysis of the proteome remains a challenging task. Phosphorylation of proteins is central to signal transduction pathways and plays an important role in plant defence against pathogens, although the immediate targets of kinases remain elusive. Determining changes in the phosphoproteome during the defence response is a major goal in molecular plant pathology. In this first description of the novel mass tagging strategy (iTRAQ™ Applied Biosystems) applied to plant pathogen interactions, we describe early changes to the phosphoproteome of Arabidopsis thaliana during the defence response to Pseudomonas syringae pv. tomato DC3000. We identified five proteins which showed reproducible differences between a control and three different bacterial challenges, thus identifying proteins potentially phosphorylated as part of a plant basal defence response. Four of the five proteins a dehydrin, a putative p23 co‐chaperone, heat shock protein 81 and a plastid‐associated protein (PAP)/fibrillin, are known to be phosphorylated or have potential phosphorylation sites. One further protein, the large subunit of Rubisco, showed a significant difference between tissue undergoing the hypersensitive response and a basal defence response. We document the reproducibility, utility and problems associated with this approach.
Electrosyntheses of high‐quality freestanding poly(fluorene‐co‐3‐methylthiophene) films with tunable fluorescence properties
Authors: Wei Zhenhong , Xu Jingkun , Pu Shouzhi , Du Yukou
Published: July 2006

The copolymerization of 3‐methylthiophene (MeT) and fluorene (FE) was successfully achieved in boron trifluoride diethyl etherate by the direct anodic oxidation of the monomer mixtures on a platinum electrode. The optimal feed ratio together with the best suitable potential for their copolymerization was determined. The as‐formed copolymer films, which were copolymerized with a feed ratio of FE/MeT = 2:1 at a constant potential of 1.3 V (vs a saturated calomel electrode), had the advantages of both poly(3‐methylthiophene) and polyfluorene, such as good electrochemical behavior, high conductivity, excellent thermal stability, and high film quality. The structure of the copolymer was investigated with ultraviolet–visible, infrared spectroscopy, and thermal analysis. Fluorescence spectroscopy studies revealed that the dedoped copolymer film in the solid state was a good blue‐light emitter with a strong emission at 435 nm and a shoulder at 459 nm. The emitting properties of the copolymer could be tuned by parameters during the electrochemical polymerization, such as the applied potential and monomer feed ratio. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4904–4915, 2006
Amphiphilic diblock star polymer catalysts via atom transfer radical polymerization
Authors: Dichtel William R. , Baek Kyung‐Youl , Fréchet Jean M. J. , Rietveld Ivo B. , Vinogradov Sergei A.
Published: July 2006

Diblock star polymers were synthesized via atom transfer radical polymerization from a palladium porphyrin macroinitiator. The arms of the star polymers had an amphiphilic design, with the central Pd‐porphyrin surrounded by a relatively hydrophobic block of poly(butyl acrylate) and terminated by a hydrophilic block of poly(oligoethyleneglycol monomethylether monomethacrylate). The size of both the interior and exterior blocks of the polymer arms were tuned over a wide range of molecular weights with the exterior block used to solubilize the stars in polar media. The star polymers showed enhanced reactivity in the oxidation of 2‐furaldehyde relative to a small molecule porphyrin, suggesting that the polymer backbone aids with catalytic turnover. Oxygen diffusion studies indicate that the polymer backbone shields the porphyrin excited state from oxygen quenching. Shielding is independent of molecular weight and polymer composition, but it is not pronounced enough to retard the rate of singlet oxygen generation under preparative photooxidation conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4939–4951, 2006
Association of pulmonary artery agenesis and hypoplasia of the lung
Authors: Vitiello Renato , Pisanti Chiara , Pisanti Antonello , Silberbach Michael
Published: July 2006

Pulmonary artery agenesis and hypoplasia of the homolateral lung occasionally occurs as an isolated lesion, but more often has associated congenital cardiac anomalies. We present a case where pulmonary artery agenesis was the sole lesion in an asymptomatic child. Pulmonary artery agenesis should be suspected in asymptomatic patients if a plain chest X‐ray shows asymmetric lung fields, lung hypoplasia, or hyperinflation of the contralateral lung. Echocardiography is the best tool to establish the diagnosis. In our opinion, invasive procedures, such as cardiac catheterization, may be postponed if there is no echocardiographic evidence of pulmonary hypertension. Pediatr Pulmonol. © 2006 Wiley‐Liss, Inc.
Effects of antenatal corticosteroid treatment on pulmonary ventilation and circulation in neonatal lambs with hypoplastic lungs
Authors: Suzuki Keiji , Hooper Stuart B. , Wallace Megan J. , Probyn Megan E. , Harding Richard
Published: July 2006

Our aim was to determine whether antenatal corticosteroids improve perinatal adaptation of the pulmonary circulation in lambs with lung hypoplasia (LH). LH was induced in 12 ovine fetuses between 105 and 140 days gestation (term ∼147 days); in 6 of these the ewe was given a single dose of betamethasone (11.4 mg im) 24 hr before delivery (LH + B). All lambs, including a control group (n = 6), were delivered at ∼140 days and ventilated for 2 hr during which arterial pressures, pulmonary blood flow (PBF), and ventilating pressure and flow were recorded. During ventilation, respiratory system compliance was lower in both LH + B and LH groups than in controls. Pulmonary vascular resistance (PVR) was lower in LH + B lambs than in LH lambs and similar to controls; PBF was reduced in LH lambs but was restored to control levels by betamethasone. The mean density of small arteries of LH + B lambs was similar to that of LH lambs (P = 0.06) and lower than in controls; the thickness of the media of small pulmonary arteries from LH + B lambs was similar to that in LH lambs and thicker than in controls. VEGF mRNA levels were not different between groups. PDGF mRNA levels in LH + B lambs were higher than in LH lambs; a similar trend (P = 0.06) was seen for PECAM‐1. SP‐C mRNA levels were greater in both LH and LH + B lambs than in controls. Effects of betamethasone were greater on indices of pulmonary circulation than ventilation. We conclude that a single dose of maternal betamethasone 24 hr prior to birth has significant favorable effects on the postnatal adaptation of the pulmonary circulation in lambs with LH. Pediatr Pulmonol. © 2006 Wiley‐Liss, Inc.