bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly superporous cholesterol‐modified poly(2‐hydroxyethyl methacrylate) scaffolds for spinal cord injury repair
Authors: Kubinová Šárka , Horák Daniel , Hejčl Aleš , Plichta Zdeněk , Kotek Jiří , Syková Eva
Published: September 2011

Modifications of poly(2‐hydroxyethyl methacrylate) (PHEMA) with cholesterol and the introduction of large pores have been developed to create highly superporous hydrogels that promote cell–surface interactions and that can serve as a permissive scaffold for spinal cord injury (SCI) treatment. Highly superporous cholesterol‐modified PHEMA scaffolds have been prepared by the bulk radical copolymerization of 2‐hydroxyethyl methacrylate (HEMA), cholesterol methacrylate (CHLMA), and ethylene dimethacrylate (EDMA) cross‐linking agent in the presence of ammonium oxalate crystals to establish interconnected pores in the scaffold. Moreover, 2‐[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) was incorporated in the polymerization recipe and hydrolyzed, thus introducing carboxyl groups in the hydrogel to control its swelling and softness. The hydrogels supported thein vitroadhesion and proliferation of rat mesenchymal stem cells. In anin vivostudy of acute rat SCI, hydrogels were implanted to bridge a hemisection cavity. Histological evaluation was done 4 weeks after implantation and revealed the good incorporation of the implanted hydrogels into the surrounding tissue, the progressive infiltration of connective tissue and the ingrowth of neurofilaments, Schwann cells, and blood vessels into the hydrogel pores. The results show that highly superporous cholesterol‐modified PHEMA hydrogels have bioadhesive properties and are able to bridge a spinal cord lesion. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Macrophage response to high number of titanium particles is cytotoxic and COX‐2 mediated and it is not affected by the particle's endotoxin content or the cleaning treatment
Authors: Schwab Luciana P. , Marlar Justin , Hasty Karen A. , Smith Richard A.
Published: September 2011

Periprosthetic osteolysis is a progressive deterioration of bone around prostheses resulting primarily from the presence of wear debris. Particulate material, number, and their interactions with environmental factors play important roles in macrophage activation around implants. We have previously shown that macrophages cultured in the presence of high numbers of cleaned titanium (Ti) particles released significant amounts of PGE2 that is potentially detrimental for bone. Cleaning of particles has become routine in most studies of macrophage/particle interactions as contaminating endotoxin elicits a macrophage cytokine response and since numerous studies have suggested that endotoxins may be present on implant materials. However, the strenuous cleaning procedure itself represents a possible source of other contaminants (such as material by‐products) that may be relevant to the prostanoid response of macrophages. To analyze this hypothesis, the macrophage response to high numbers of cleaned Ti particles was compared to that of unclean particles and to particles that were subjected to a short version of the cleaning procedure. It was found that neither the high amount of endotoxin on the unclean particles nor the duration of the cleaning procedure had an effect on the release of PGE2 and the decrease in cell viability in response to high number of Ti particles. Evidence of a possible relationship between these two variables is presented. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Autologous fibrin scaffolds cultured dermal fibroblasts and enriched with encapsulated bFGF for tissue engineering
Authors: de la Puente Pilar , Ludeña Dolores , Fernández Ana , Aranda Jose L. , Varela Gonzalo , Iglesias Javier
Published: September 2011

Autologous fibrin scaffolds (AFSs) enriched with cells and specific growth factors represent a promising biocompatible scaffold for tissue engineering. Here, we analyzed the in vitro behavior of dermal fibroblasts (DFs) (cellular attachment, distribution, viability and proliferation, histological and immunohistochemical changes), comparing AFS with and without alginate microcapsules loaded with basic fibroblast growth factor (bFGF), to validate our scaffold in a future animal model in vivo. In all cases, DFs showed good adhesion and normal distribution, while in scaffolds with bFGF at 14 days, the cell counts detected in proliferation and viability assays were greatly improved, as was the proliferative state, and there was a decrease in muscle specific actin expression and collagen synthesis in comparison with the scaffolds without bFGF. In addition, the use of plasma without fibrinogen concentration methods, together with the maximum controlled release of bFGF at 14 days, favored cell proliferation. To conclude, we have been able to create an AFS enriched with fully functional DFs and release‐controlled bFGF that could be used in multiple applications for tissue engineering © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Characterization and behavior of anesthetic bioactive textile complex in vitro condition
Authors: Simovic Lj. , Skundric P. , Baralic A. Medovic , Pajic‐Lijakovic I. , Milutinovic‐Nikolic A.
Published: September 2011

In this study, a bioactive complex containing nonwoven textile material (polypropilene (PP)/viscose), chitosan hydrogel, and lidocaine hydrochloride, was designed. The purpose of such biomedical textile was in the treatment of painful sites. Mercury intrusion porosimetry was used in order to estimate the influence of medical impregnation on porous structure of nonwoven material. It was estimated that more than 97% of pores in untreated nonwoven sample were larger than 15 μm. Anesthetic treatment of nonwoven reduced total pore volume of ultramacropores and macropores, while total pore volume of mesopores slightly increased. Lidocaine hydrochloride release from the anesthetic/chitosan hydrogel/nonwoven complex was measured in vitro by Franz diffusion cell technique. Mathematical model was developed to estimate the release of the lidocaine from obtained bioactive textile material. The diffusive transport of lidocaine hydrochloride through three connected layers, i.e., polymer hydrogel, membrane, and solution is modeled based on Fick's second law. Taking all the relevant conditions, regarding this experiment, into consideration, the coefficient of lidocaine diffusion through the polymer hydrogel, as well as the concentration ratio parameter were determined by the mathematical model. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Crosslinking of poly(L‐lactide) nanofibers with triallyl isocyanutrate by gamma‐irradiation for tissue engineering application
Authors: He Chuanglong , Feng Wei , Cao Lijun , Fan Linpeng
Published: September 2011

The radiation crosslinked poly(L‐lactide) (PLLA) electrospun nanofibers have been developed with improved thermal stability and mechanical properties. Trially isocyanurate (TAIC) were added into PLLA solution at different weight ratios (1, 3, and 5%) and electrospun into nanofibrous mats, the mats were then irradiated by gamma ray at different radiation doses (5, 10, and 25 kGy) to crosslink the PLLA chains. Their surface morphology, thermal properties, mechanical properties, and biodegradation properties were investigated and compared before and after gamma irradiation. Furthermore, the in vitro biocompatibilities were also evaluated by using mouse L929 fibroblasts. The results indicated that the efficient crosslinking networks can be generated when the TAIC content is higher than 3%. The thermal stability and tensile mechanical properties were significantly increased at higher irradiation dose of 10 and 25 kGy. However, radiation dose at 25 kGy have an adverse effect on the thermal stability of crosslinked samples due to thermal degradation induced by irradiation, the crosslinked samples irradiated at 10 kGy exhibited the best enzymatic degradation. The in vitro results also revealed that the crosslinked PLLA/TAIC composite nanofibers did not induce cytotoxic effects and are suitable for cell growth. Therefore, the crosslinked PLLA nanofibers are one of the promising materials for future tissue engineering applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Osteogenic gene expression of canine bone marrow stromal cell and bacterial adhesion on titanium with different nanotubes
Authors: Yu Wei‐Qiang , Jiang Xing‐Quan , Xu Ling , Zhao Yan‐Fang , Zhang Fu‐Qiang , Cao Xin
Published: September 2011

Bacterial infection and osseointegration of implant‐biomaterials all play important roles in the success of an orthopedic prosthesis or a dental‐implant. In this work, we evaluated the osteogenic gene expression of canine bone marrow stromal cells (CBMSCs) and the adhesion ofStaphylococcus aureus(ATCC 12598) on different diameter TiO2nanotube layers. The CBMSCs cultured on 30 and 70 nm nanotubes displayed polygon shape, but obviously elongated when the diameter of nanotubes turned to 120 nm. A significant increase in CBMSCs proliferation by as much as about ∼300%, and osteogenic gene (RUNX‐2, OPN, COL‐1, and OCN) expression were observed on the 120 nm diameter nanotubes when compared to the smooth Ti. However, the adhesion of bacteria also increased with an increased tube diameter and reached highest value on 120 nm nanotubes after 4 h of incubation. ∼300–400% increase in bacterial attached to 120 nm nanotubes in contract to the smooth Ti. These data suggested reducing bacteria colonization should be considered when larger diameter nanotubes with better osteogenic property would be used as orthopedic implants or dental implants. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
The role of vascular calcification in inducing fatigue and fracture of coronary stents
Authors: Halwani Dina O. , Anderson Peter G. , Brott Brigitta C. , Anayiotos Andreas S. , Lemons Jack E.
Published: September 2011

Traditional approaches for in‐vitro pulsatile and fatigue testing of endovascular stents do not take into consideration the pathologies of the stented vessel and their associated biomechanical effects. One important pathology is calcification, which may be capable of inducing changes in the vessel wall leading to inhomogeneous distribution of stresses combined with wall motion during the cardiac cycle. These local property changes in the region adjacent to stents could directly influence in‐vivo stent performance. Seven cases containing a total of 18 stents were obtained from autopsy. Radiographs were evaluated and vessels were sectioned for histology and stent topographical analysis. Stents were retrieved by chemical removal of surrounding tissue and surfaces were evaluated using 3D digital optical and scanning electron microscopy for biomechanical abrasion and fracture features. Pathologic complications such as restenosis and thrombus formation were assessed from histological sections. Direct evidence of fracture was found in 6 of the 7 cases (in 12 out of 18 stents; 9 drug eluting and 3 bare metal). The degree of stent alterations was variable, where separation of segments due to fracture occurred mostly in drug‐eluting stents. All fracture surfaces were representative of a high cycle fatigue mechanism. These fractures occurred in complex lesions involving the presence of diffuse calcification alone, or in combination with vessel angulations and multiple overlapping stents. Morphologic analysis of tissue at or near some fracture sites showed evidence of thrombus formation and/or neointimal tissue growth. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Calcium phosphate bioceramics fabricated from extracted human teeth for tooth tissue engineering
Authors: Lim Ki‐Taek , Suh Je Duck , Kim Jangho , Choung Pill‐Hoon , Chung Jong Hoon
Published: September 2011

Bioceramic tooth powders were prepared via heat treatment of extracted human teeth using sintering temperatures between 600°C and 1200°C, and their properties were investigated for potential tooth tissue engineering. The sintered human tooth powders were characterized using thermal analysis (thermogravimetric analysis (TG) and differential thermal analysis (DTA)), field emission scanning electron microscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, and Fourier transformed infrared (FTIR) spectroscopy. Additionally, the phase constitutions and chemical homogeneities of the composite samples were examined using a quantitative chemical analysis with inductively coupled plasma spectroscopy. The results revealed that the annealing process produced useful hydroxyapatite‐based bioceramic biomaterials when annealed above 1000°C. The FTIR spectra and the TG/DTA thermograms of the tooth powders indicated the presence of organic compounds, which were completely removed after annealing at temperatures above 1000°C. The tooth powders annealed between 1000°C and 1200°C had good characteristics as bioceramic biomaterials. Furthermore, the biocompatibility of each tooth powder was evaluated using in vitro and in vivo techniques; our results indicate that the prepared human tooth powders have great potential for tooth tissue engineering applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Reinforced nanohydroxyapatite/polyamide66 scaffolds by chitosan coating for bone tissue engineering
Authors: Huang Di , Zuo Yi , Zou Qin , Wang Yanying , Gao Shibo , Wang Xiaoyan , Liu Haohuai , Li Yubao
Published: September 2011

High porosity of scaffold is always accompanied by poor mechanical property; the aim of this study was to enhance the strength and modulus of the highly porous scaffold of nanohydroxyapatite/polyamide66 (n‐HA/PA66) by coating chitosan (CS) and to investigate the effect of CS content on the scaffold physical properties and cytological properties. The results show that CS coating can reinforce the scaffold effectively. The compress modulus and strength of the CS coated n‐HA/PA66 scaffolds are improved to 32.71 and 2.38 MPa, respectively, being about six times and five times of those of the uncoated scaffolds. Meanwhile, the scaffolds still exhibit a highly interconnected porous structure and the porosity is approximate about 78%, slightly lower than the value (84%) of uncoated scaffold. The cytological properties of scaffolds were also studied in vitro by cocultured with osteoblast‐like MG63 cells. The cytological experiments demonstrate that the reinforced scaffolds display favorable cytocompatibility and have no significant difference with the uncoated n‐HA/PA66 scaffolds. The CS reinforced n‐HA/PA66 scaffolds can meet the basic mechanical requirement of bone tissue engineering scaffold, presenting a potential for biomedical application in bone reconstruction and repair. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Highly packed and aligned fluoride substituted hydroxyapatite via a surfactant‐free process
Authors: Xia Wei , Lausmaa Jukka , Thomsen Peter , Engqvist Håkan
Published: September 2011

Biomolecules and surfactants are believed to be the key factors for reconstruction of tooth enamel and preparation of fluoride hydroxyapatite coating with enamel‐like structure on dental implants. We have developed an alternative surfactant‐free biomimetic method to stimulate growth of fluoride substituted hydroxyapatite coatings with highly packed and aligned structure on metallic substrates. Oxidized titanium plates were chosen as the substrates. The biomimetic fluoride hydroxyapatite was prepared by immersing the pretreated Ti plates into the phosphate‐buffered solution with Ca2+, H2PO4−, HPO42−, and F−. The pH value was controlled at 7.4 at the beginning. Every titanium plate (10 mm × 10 mm × 1 mm) was soaked into 20 mL of ion doped phosphate buffered solution in sealed plastic bottles, kept at 37°C or 60°C without stirring for time periods of 1 day to 2 weeks. After immersion, the samples were removed from the solution, rinsed with deionized water and allowed to dry in air. The fluoride substituted hydroxyapatite layer, composed of needle‐like crystallites with the diameter of 10–20 nm, was well‐organized and tightly packed. XRD results showed a sharper and stronger (002) peak, which could be used to explain that there was a preferable orientation along the c axis. The coating could be reconstructed on the former layer if the mineralization process was repeated, and the structure of the coating could be preserved. The method could be used to construct well organized fluoride substitute hydroxyapatite coating on metal implants. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Mesoporous titanium dioxide coating for metallic implants
Authors: Xia Wei , Grandfield Kathryn , Hoess Andreas , Ballo Ahmed , Cai Yanling , Engqvist Håkan
Published: September 2011

A bioactive mesoporous titanium dioxide (MT) coating for surface drug delivery has been investigated to develop a multifunctional implant coating, offering quick bone bonding and biological stability. An evaporation induced self‐assembly (EISA) method was used to prepare a mesoporous titanium dioxide coating of the anatase phase with BET surface area of 172 m2/g and average pore diameter of 4.3 nm. Adhesion tests using the scratch method and an in situ screw‐in/screw‐out technique confirm that the MT coating bonds tightly with the metallic substrate, even after removal from bone. Because of its high surface area, the bioactivity of the MT coating is much better than that of a dense TiO2 coating of the same composition. Quick formation of hydroxyapatite (HA) in vitro can be related to enhance bonding with bone. The uptake of antibiotics by the MT coating reached 13.4 mg/cm3 within a 24 h loading process. A sustained release behavior has been obtained with a weak initial burst. By using Cephalothin as a model drug, drug loaded MT coating exhibits a sufficient antibacterial effect on the material surface, and within millimeters from material surface, against E.coli. Additionally, the coated and drug loaded surfaces showed no cytotoxic effect on cell cultures of the osteoblastic cell line MG‐63. In conclusion, this study describes a novel, biocompatiblemesoporous implant coating, which has the ability to induce HA formation and could be used as a surface drug‐delivery system. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Delayed short-course treatment with teriparatide (PTH1–34) improves femoral allograft healing by enhancing intramembranous bone formation at the graft–host junction
Authors: Takahata Masahiko , Schwarz Edward M , Chen Tony , O'Keefe Regis J , Awad Hani A
Published: September 2011

Clinical management of critical bone defects remains a major challenge. Despite preclinical work demonstrating teriparatide (PTH1–34) effectiveness in small animals, inconclusive data from clinical trials have raised questions of dose and regimen. To address this, we completed a comprehensive study in the murine femoral allograft model, to assess the effects of dose (0.4, 4, and 40 µg/kg/day) and various treatment regimens on radiographic, histologic, and biomechanical healing at 2, 4, and 9 weeks. Only the high dose (40 µg/kg) of PTH1–34 demonstrated significant effects when given daily over 9 weeks. Remarkably, equivalent biomechanical results were obtained with delayed, short treatment from 2 to 6 weeks that did not induce a significant increase in endochondral bone formation and callus volume. In contrast, PTH1–34 treatment from 1 to 5 weeks postop demonstrated similar osteogenic effects as immediate daily treatment for 9 weeks, but failed to achieve a significant increase in biomechanics at 9 weeks. MicroCT and histologic analyses demonstrated that the 2-week delay in treatment allowed for timely completion of the endochondral phase, such that the prominent effects of PTH1–34 were enhanced intramembranous bone formation and remodeling at the graft–host junction. These findings support the potential use of PTH1–34 as an adjuvant therapy for massive allograft healing, and suggest that there may be an ideal treatment window in which a short course is administered after the endochondral phase to promote osteoblastic bone formation and remodeling to achieve superior union with modest callus formation. © 2012 American Society for Bone and Mineral Research
Osteoblast extracellular Ca2+-sensing receptor regulates bone development, mineralization, and turnover
Authors: Dvorak-Ewell Melita M , Chen Tsui-Hua , Liang Nathan , Garvey Caitlin , Liu Betty , Tu Chialing , Chang Wenhan , Bikle Daniel D , Shoback Dolores M
Published: September 2011

The extracellular Ca2+-sensing receptor (CaR), a G protein-coupled receptor responsible for maintenance of calcium homeostasis, is implicated in regulation of skeletal metabolism. To discern the role of the osteoblast CaR in regulation of bone development and remodeling, we generated mice in which the CaR is excised in a broad population of osteoblasts expressing the 3.6-kb a1(I) collagen promoter. Conditional knockouts had abnormal skeletal histology at birth and developed progressively reduced mineralization secondary to retarded osteoblast differentiation, evident by significantly reduced numbers of osteoblasts and decreased expression of collagen I, osteocalcin, and sclerostin mRNAs. Elevated expression of ankylosis protein, ectonucleotide pyrophosphatase/phosphodiesterase 1, and osteopontin mRNAs in the conditional knockout indicate altered regulation of genes important in mineralization. Knockout of the osteoblast CaR also resulted in increased expression of the receptor activator of NF-κB ligand (RANKL), the major stimulator of osteoclast differentiation and function, consistent with elevated osteoclast numbers in vivo. Osteoblasts from the conditional knockouts exhibited delayed differentiation, reduced mineralizing capacity, altered expression of regulators of mineralization, and increased ability to promote osteoclastogenesis in coculture experiments. We conclude that CaR signaling in a broad population of osteoblasts is essential for bone development and remodeling and plays an important role in the regulation of differentiation and expression of regulators of bone resorption and mineralization. © 2011 American Society for Bone and Mineral Research
Effects of three-monthly oral 150,000 IU cholecalciferol supplementation on falls, mobility, and muscle strength in older postmenopausal women: A randomized controlled trial
Authors: Glendenning Paul , Zhu Kun , Inderjeeth Charles , Howat Peter , Lewis Joshua R , Prince Richard L
Published: September 2011

Daily vitamin D in addition to calcium supplementation reduces falls and fractures in older women. However, poor adherence to therapy is a common clinical problem. To examine the effects of supervised oral 3-monthly vitamin D therapy on falls, muscle strength, and mobility, we conducted a 9-month randomized, double-blind, placebo-controlled trial in 686 community-dwelling ambulant women aged over 70 years. Participants received either oral cholecalciferol 150,000 IU every 3 months (n = 353) or an identical placebo (n = 333). All participants were advised to increase dietary calcium intake. Falls data were collected 3-monthly. At baseline, 3, 6, and 9 months, muscle strength was measured by a handheld dynamometer and mobility by the Timed Up and Go (TUG) test. Serum 25 hydroxyvitamin D (25OHD) was measured in a subgroup of 40 subjects. Mean age at baseline was 76.7 ± 4.1 years. The average serum 25OHD value at baseline was 65.8 ± 22.7 nmol/L. By 3, 6, and 9 months after supplementation, 25OHD levels of the vitamin D group were approximately 15 nmol/L higher than the placebo group. Calcium intake did not change significantly between baseline (864 ± 412 mg/day) and 9 months (855 ± 357 mg/day). Faller rates in the two groups did not differ: vitamin D group, 102 of 353 (29%); placebo group, 89 of 333 (27%). At 9 months, compared to placebo or baseline, muscle strength, and TUG were not altered by vitamin D. In conclusion, oral cholecalciferol 150,000 IU therapy administered 3-monthly had neither beneficial nor adverse effects on falls or physical function. These data together with previous findings confirm that intermittent large doses of vitamin D are ineffective or have a deleterious effect on falls. Thus despite adherence issues with daily vitamin D replacement, an intermittent, high-dose vitamin D regimen cannot be supported as a strategy to reduce falls and fractures. © 2012 American Society for Bone and Mineral Research
The potential value of monitoring bone turnover markers among women on alendronate
Authors: Bell Katy JL , Hayen Andrew , Irwig Les , Hochberg Marc C , Ensrud Kristine E , Cummings Steven R , Bauer Douglas C
Published: September 2011

Biochemical markers of bone turnover have been proposed to monitor the response to bisphosphonate therapy for osteoporosis, but this requires true between-person differences in the response to therapy. Using mixed models we analyzed three annual measurements of two markers (bone alkaline phosphatase [BAP] and cross-linked N-telopeptide of type I collagen [NTX]) from the Fracture Intervention Trial. We compared marker variation among women allocated to alendronate with that among women allocated to placebo to estimate how much variation was due to true between-person differences in response to treatment, and how much was due to random within-person fluctuations unrelated to treatment. For both markers we found that the mean effect of treatment differed by the baseline level of the marker. After allowing for this and other effects, we found large true between-person differences in response to treatment for both markers, with a coefficient of variation (CV) for NTX of 25.1% and for BAP of 21.2%. However, random within-person fluctuation was even larger, with a CV for change in NTX of 42.5% and for change in BAP of 25.8%. Although repeated measurements have the potential to reduce within person variability, even triplicate baseline marker measurements resulted in an averaged value that was only within 31% of the true value with 95% certainty. In summary, although bone turnover markers appear promising for monitoring between-person differences in response to treatment, their use in clinical practice is currently limited by large random within-person variation. © 2012 American Society for Bone and Mineral Research
Vitamin D insufficiency is prevalent and vitamin D is inversely associated with parathyroid hormone and calcitriol in pregnant adolescents
Authors: Young Bridget E , McNanley Thomas J , Cooper Elizabeth M , McIntyre Allison W , Witter Frank , Harris Z Leah , O'Brien Kimberly O
Published: September 2011

Few large studies have assessed changes in calcitropic hormones and maternal 25-hydroxyvitamin D (25(OH)D) status across pregnancy, and how this may impact maternal bone turnover and neonatal hormone status. We aimed to identify determinants of 25(OH)D, parathyroid hormone (PTH), and calcitriol across pregnancy in a longitudinal study of 168 pregnant adolescents (≤18 years of age). Maternal 25(OH)D, PTH, and calcitriol were assessed at mid-gestation (∼26 weeks), delivery, and in cord blood. Data were related to measures of maternal anthropometrics, dietary intake, physical activity, and bone turnover markers. Approximately 50% of teens and their infants had serum 25(OH)D ≤ 20 ng/mL; 25(OH)D was lower in African Americans versus whites (p < 0.001). PTH increased across gestation (p < 0.001). Elevated PTH (≥60 pg/mL) was detected in 25% of adolescents at delivery, and was associated with increased concentrations of serum N-telopeptide (NTX) (p = 0.028). PTH and calcitriol did not significantly differ across the range of Ca intake consumed (257–3220 mg/d). In the group as a whole, PTH was inversely associated with 25(OH)D in maternal circulation at mid-gestation (p = 0.023) and at delivery (p = 0.019). However, when the cohort was partitioned by 25(OH)D status, this relationship was only present in those with 25(OH)D ≤ 20 ng/mL, suggestive of a threshold below which 25(OH)D impacts PTH during pregnancy. Mid-gestation 25(OH)D was inversely associated with calcitriol at delivery (p = 0.023), irrespective of Ca intake. Neonatal PTH and calcitriol were significantly lower than (p < 0.001), but unrelated to maternal concentrations. These findings indicate that maternal 25(OH)D status plays a role in calcitropic hormone regulation in pregnant adolescents. © 2012 American Society for Bone and Mineral Research
D,L‐sulforaphane‐induced apoptosis in human breast cancer cells is regulated by the adapter protein p66Shc
Authors: Sakao Kozue , Singh Shivendra V.
Published: September 2011

Cancer chemopreventive response to D,L‐sulforaphane (SFN), a synthetic racemic analogue of broccoli constituent L‐sulforaphane, is partly attributable to apoptosis induction, but the mechanism of cell death is not fully understood. The present study demonstrates a critical role for adapter protein p66Shc in SFN‐induced apoptosis. Immortalized mouse embryonic fibroblasts (MEF) derived from p66shc knockout mice were significantly more resistant to SFN‐induced apoptosis, collapse of mitochondrial membrane potential, and reactive oxygen species (ROS) production compared with MEF obtained from the wild‐type mice. Notably, a spontaneously immortalized and non‐tumorigenic human mammary epithelial cell line (MCF‐10A) was resistant to SFN‐induced ROS production and apoptosis. Stable overexpression of manganese superoxide dismutase in MCF‐7 and MDA‐MB‐231 human breast cancer cells conferred near complete protection against SFN‐induced apoptosis and mitochondrial membrane potential collapse. SFN treatment resulted in increased S36 phosphorylation and mitochondrial translocation of p66shc in MDA‐MB‐231 and MCF‐7 cells, and SFN‐induced apoptosis was significantly attenuated by RNA interference of p66shc in both cells. SFN‐treated MDA‐MB‐231 and MCF‐7 cells also exhibited a marked decrease in protein level of peptidyl prolyl isomerase (Pin1), which is implicated in mitochondrial translocation of p66shc. However, stable overexpression of Pin1 failed to alter proapoptotic response to SFN at least in MCF‐7 cells. Finally, SFN‐induced S36 phosphorylation of p66Shc was mediated by protein kinase Cβ (PKCβ), and pharmacological inhibition of PKCβ significantly inhibited apoptotic cell death resulting from SFN exposure. In conclusion, the present study provides new insight into the mechanism of SFN‐induced apoptosis involving PKCβ ‐mediated S36 phosphorylation of p66shc. J. Cell. Biochem. 113: 599–610, 2012. © 2011 Wiley Periodicals, Inc.
Interaction of Wnt/β‐catenin and notch signaling in the early stage of cardiac differentiation of P19CL6 cells
Authors: Li Binhong , Jia Zhuqing , Wang Tao , Wang Weiping , Zhang Chenguang , Chen Ping , Ma Kangtao , Zhou Chunyan
Published: September 2011

Notch and Wnt/β‐catenin signaling both play essential roles and interact closely in cardiomyocyte differentiation but the mechanism of interaction is largely unknown. Here we show that activation of Notch signaling in undifferentiated P19CL6 cells promoted cardiac differentiation, indicated by upregulated expression of early cardiac markers and activated the canonical Wnt pathway, suggested by augmented nuclear translocation of β‐catenin. Further activation of the Notch pathway in early differentiating cells (at day 3) inhibited expression of a specific cardiac progenitor marker Islet1 but had no influence on β‐catenin translocation. Notch signaling thus played biphasic roles in the early stage of cardiomyocyte differentiation and Wnt/β‐catenin signaling. Unlike Notch signaling, Wnt signaling promoted cardiomyocyte differentiation and activated the Notch pathway in either undifferentiated or early differentiating cells. Additionally, β‐catenin, recombination signal sequence binding protein‐Jkappa (RBP‐Jκ), and Notch1 intracellular domain (NICD‐1) formed a transcriptional complex which was recruited to the Hes1 promoter region, indicating direct transcriptional regulation of Hes1. We thus document a specific reciprocal interaction between these two signaling pathways during early stage cardiac differentiation of P19CL6 cells. J. Cell. Biochem. 113: 629–639, 2012. © 2011 Wiley Periodicals, Inc.
Cold‐blooded snipers: thermal independence of ballistic tongue projection in the salamander Hydromantes platycephalus
Authors: Deban Stephen M. , Richardson Jason C.
Published: September 2011

Plethodontid salamanders of the genus Hydromantes capture prey using the most extreme tongue projection among salamanders, and can shoot the tongue a distance of 80% of body length in less than 20 msec. The tongue skeleton is projected from the body via an elastic‐recoil mechanism that decouples muscle contraction from tongue projection, amplifying muscle power tenfold. We tested the hypothesis that the elastic‐recoil mechanism also endows tongue projection with low thermal dependence by examining the kinematics and dynamics of tongue projection in Hydromantes platycephalus over a range of body temperatures (2–24°C). We found that H. platycephalus maintained tongue‐projection performance over the tested temperature range and that tongue projection showed thermal independence (Q10 values of 0.94–1.04) of all performance parameters including projection distance, average velocity, and peak instantaneous values of velocity, acceleration, and power. Nonelastic, muscle‐powered tongue retraction, in contrast, responded to temperature changes significantly differently than elastic tongue projection; performance parameters of retraction displayed thermal dependence typical of muscle‐powered movement (Q10 values of 1.63–4.97). These results reveal that the elastic‐recoil mechanism liberates tongue projection from the effects of temperature on muscle contractile rates. We suggest that relative thermal independence is a general characteristic of elastic‐recoil mechanisms and may promote the evolution of these mechanisms in ectothermic animals. J. Exp. Zool. 315:618–630, 2011. © 2011 Wiley Periodicals, Inc.
Thermosensitive hydrogel for prolonged delivery of lentiviral vector expressing neurotrophin‐3 in vitro
Authors: McMahon Siobhan S , Nikolskaya Natalia , Choileáin Siobhan Ní , Hennessy Niamh , O'Brien Timothy , Strappe Padraig M , Gorelov Alexander , Rochev Yury
Published: September 2011

Background

The development of tissue engineering scaffolds for gene delivery has the potential to enhance gene transfer efficiency and safety via controlled temporal and spatial delivery. Lentiviral delivery can be carried out using the natural biopolymer thermoresponsive gel, chitosan/β‐glycerol phosphate (β‐GP) as a carrier.

Methods

Three chitosan/β‐GP scaffolds were prepared with varying concentrations of chitosan and β‐GP to obtain a pH and gelation temperature suitable for in situ delivery. A lentiviral vector expressing either green fluorescent protein (Lenti GFP) or neurotrophin‐3 (Lenti NT‐3) was incorporated into the chitosan/β‐GP scaffolds and also into collagen 0.1% w/v (control). Viral elution medium was removed at various timepoints and added to the culture medium of pre‐seeded HeLa or primary dorsal root ganglia (DRG) cells, respectively. GFP gene expression was quantified using fluorescence‐activated cell sorting analysis. The effect of Lenti NT‐3 was analyzed by measuring DRG neurite outgrowth.

Results

Collagen displayed its most significant elution of virus on day 1 and chitosan/β‐GP (with a final concentration of 2.17% chitosan) on day 3.

Conclusions

The system shows promise for the in situ, thermoresponsive delivery of lentiviral vectors providing long‐term gene expression for therapeutic factors to treat conditions such as injury to the nervous system. Copyright © 2011 John Wiley & Sons, Ltd.
Myoanatomy and serotonergic nervous system of plumatellid and fredericellid phylactolaemata (lophotrochozoa, ectoprocta)
Authors: Schwaha Thomas , Wanninger Andreas
Published: September 2011

The phylogenetic position of the Ectoprocta within the Lophotrochozoa is discussed controversially. For gaining more insight into ectoproct relationships and comparing it with other potentially related phyla, we analysed the myoanatomy and serotonergic nervous system of adult representatives of the Phylactolaemata (Plumatella emarginata, Plumatellavaihiriae, Plumatella fungosa, Fredericella sultana). The bodywall contains a mesh of circular and longitudinal muscles. On its distal end, the orifice possesses a prominent sphincter and continues into the vestibular wall, which has longitudinal and circular musculature. The tentacle sheath carries mostly longitudinal muscle fibres in Plumatella sp., whereas F. sultana also possesses regular circular muscle fibres. Three groups of muscles are associated with the lophophore: 1) Lophophoral arm muscles (missing in Fredericella), 2) epistome musculature and 3) tentacle musculature. The epistome flap is encompassed by smooth muscle fibres. A few fibres extend medially over the ganglion to its proximal floor. Abfrontal tentacle muscles have diagonally arranged muscle fibres in their proximal region, whereas the distal region is formed by a stack of muscles that resemble an inverted ‘V’. Frontal tentacle muscles show more variation and either possess one or two bases. The digestive tract possesses circular musculature which is striated except at the intestine where it is composed of smooth muscle fibres. The serotonergic nervous system is concentrated in the cerebral ganglion. From the latter a serotonergic nerve extends to each tentacle base. In Plumatella the inner row of tentacles at the lophophoral concavity lacks serotonergic nerves. Bodywall musculature is a common feature in many lophotrochozoan phyla, but among other filter feeders like the Ectoprocta is only present in the ‘lophophorate’ Phoronida. The longitudinal tentacle musculature is reminiscent of the condition found in phoronids and brachiopods, but differs to entoproct tentacles. Although this study shows some support for the ‘Lophophorata’, more comparative analyses of possibly related phyla are required. J. Morphol., 2011. © 2011 Wiley Periodicals, Inc.
Structure and ultrastructure of spermatozoa and spermiogenesis in three species of Lucilia Robineau‐desvoidy, 1830 (Diptera: Calliphoridae)
Authors: Name Khesller P.O. , Barros‐Cordeiro Karine B. , Filho José B. Gama , Wolff Marta , Pujol‐Luz José R. , Báo Sônia N.
Published: September 2011

Morphology of male internal reproductive organs, spermatozoa, and spermiogenesis of the blow‐flies Lucilia cuprina, Lucilia eximia, and Lucilia peruviana is first described here, using light and transmission electron microscopy. Spermiogenesis follows the characteristics described for others insect species. The spermatozoa of L. cuprina are similar to those described for other Brachycera. However, in L. eximia and L. peruviana, some differences were found. In L. cuprina and L. eximia species, the spermatozoa are long and thin, measuring about 211 μm and 146 μm in length, of which the head region measures approximately 19 μm and 17 μm, respectively. A polymorphism was observed in L. cuprina and L. eximia spermatozoa. In all three species, the head includes a monolayered acrosome with electron‐lucent material. The shape of the nucleus, in cross sections, varies from circular to oval with completely condensed chromatin. Implantation of the axoneme was observed in the middle region of the nucleus, known as the “peg” region. In the next region, the beginning of two mitochondrial derivatives of similar diameter and different lengths in L. cuprina and only one in L. eximia and L. peruviana was observed. In the overlap region, the following structures were observed: nucleus, centriolar adjunct, mitochondrial derivatives, and axoneme. The axoneme is of a conventional insectan type with a 9 + 9 + 2 microtubular arrangement. The male internal reproductive tract consists of testis, deferent ducts, a strongly developed seminal vesicle, accessory glands, and ejaculatory duct. These features are consistent with the structural diversity of the dipteran reproductive tract and spermatozoa, comprising an essential tool for understanding the complex variations found in the Diptera. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc.
Kinetic and thermodynamic investigation of mancozeb degradation in tomato homogenate during thermal processing
Authors: Certel Muharrem , Cengiz Mehmet F , Akçay Mehmet
Published: September 2011

BACKGROUND: The kinetic and thermodynamic parameters of mancozeb degradation in tomato homogenates under the conditions prevailing in the manufacture of tomato products (at 60–100 °C for 0–60 min) were investigated. A gas chromatography–mass spectrometry method was used to analyse residual mancozeb in tomato homogenate. Ethylenethiourea (ETU), the main toxic degradation product of mancozeb, was measured by high‐performance liquid chromatography (HPLC)–with photodiode array detector (PDA).

RESULTS: The degradation of mancozeb and the formation of ETU in tomato homogenates were adequately described as first‐order kinetics. Dependence of the rate constant followed the Arrhenius relationship. Apparent activation energies, temperature coefficients, half time and time to reduce to 90% of the initial value of mancozeb were calculated as kinetic parameters. The thermodynamic parameters of mancozeb were also described as Δgd = − 2.440 and 7.074 kJ mol−1; Δhd = − 32.555 and − 42.767 kJ mol−1; Δsd = − 0.090 and − 0.150 kJ mol−1 K−1; Ke = 0.414 and 9.797 L g−1 for 333 and 373 K respectively.

CONCLUSION: Current findings may shed light on the reduction of mancozeb residue and its toxic degradation product during thermal processing of tomatoes and may also be valuable in awareness and prevention of potential risks from dietary exposure. Copyright © 2011 Society of Chemical Industry
Quality assessment of tomato landraces and virus‐resistant breeding lines: quick estimation by near infrared reflectance spectroscopy
Authors: García‐Martínez Santiago , Gálvez‐Sola Luis N , Alonso Arantxa , Agulló Enrique , Rubio Fernando , Ruiz Juan J , Moral Raúl
Published: September 2011

BACKGROUND: Several tomato landraces are very popular in south‐eastern Spain for their organoleptic fruit quality, but these cultivars are highly susceptible to several viruses. A breeding programme is being carried out for the introduction of virus resistances into these landraces. In the last steps of our breeding programme a high number of breeding lines must be evaluated for agronomic and organoleptic quality parameters. Near infrared reflectance spectroscopy (NIRS) technology shows considerable promise and is ideally suited to the requirements of breeders.

RESULTS: Significant differences between a set of 35 tomato breeding lines, seven landraces and one commercial hybrid were observed for quality and mineral content parameters, suggesting that there are considerable levels of genetic diversity between the cultivar groups studied. Using NIRS on dry samples of tomato constitutes a feasible technique to estimate the content of several minerals (C, N, P, K, Ca, Na, Mn, Mg and Cu) according to the coefficient of determination for calibration (R2 > 0.90). NIRS estimations of soluble solids content and titratable acidity obtained were considered useful only for general screening purposes.

CONCLUSIONS: NIRS technology may be a useful tool in the selection of lines coming out of tomato breeding programs, allowing a quick estimation of mineral content. However, the estimation of soluble solids content and titratable acidity by NIRS must be improved. Copyright © 2011 Society of Chemical Industry
Distance from riparian edge reduces brood parasitism of southwestern willow flycatchers, whereas parasitism increases nest predation risk
Authors: Stumpf Katie J. , Theimer Tad C. , Mcleod Mary Anne , Koronkiewicz Thomas J.
Published: September 2011

The southwestern willow flycatcher (Empidonax traillii extimus) is a federally endangered subspecies that breeds in increasingly fragmented and threatened habitat. We examined whether temporal and habitat characteristics were associated with risk of predation and probability of brood parasitism by brown‐headed cowbirds (Molothrus ater) on flycatcher nests at 6 sites in southern Nevada and northwestern Arizona, USA. For nest predation, we found the most support for a model that included date and an interaction between parasitism status and nesting stage. Daily nest survival decreased from 0.87 (95% CI = 0.81–0.93) to 0.78 (95% CI = 0.72–0.84) through the season for parasitized nests but remained relatively constant for unparasitized nests (0.93, 95% CI = 0.91–0.95 to 0.92, 95% CI = 0.91–93). Parasitized nests had lower survival than non‐parasitized nests during the incubation (0.85, 95% CI = 0.84–0.86 vs. 0.92, CI = 0.91–0.93) and nestling (0.79, 95% CI = 0.77–0.81 vs. 0.91, 95% CI = 0.90–0.92) stages. Of the variables included in our parasitism candidate models, model‐averaged coefficients and odds ratios supported only distance to habitat edge; odds of parasitism decreased 1% for every 1 m from the habitat edge. Nests greater than 100 m from an edge were 50% less likely to be parasitized as those on an edge, however, only 52 of 233 nests (22%) were found at this distance. Where management and conservation goals include reducing nest losses due to parasitism, we recommend restoration of habitat patches that minimize edge and maximize breeding habitat further from edges. At sites where cowbirds have been documented as important nest predators, controlling cowbirds may be one option, but further study of the link between parasitism and nest predation and the identification of major nest predators at specific sites is warranted. © 2011 The Wildlife Society.
Light‐mediated ferroelectric domain engineering and micro‐structuring of lithium niobate crystals
Authors: Ying C.Y.J. , Muir A.C. , Valdivia C.E. , Steigerwald H. , Sones C.L. , Eason R.W. , Soergel E. , Mailis S.
Published: September 2011

An overview is presented of recently developed light‐mediated methods for ferroelectric domain engineering of lithium niobate single crystals. These methods include light‐assisted poling, UV laser‐induced inhibition of poling, and all‐optical poling. In addition to the primary application of ferroelectric domain patterns, namely the realization of non‐linear optical devices, the ability of transferring a domain pattern into a topographical structure by domain selective etching allows also for surface structuring of lithium niobate. This intertwining between ferroelectric domain patterns and surface topography has been used to fabricate exquisite micro‐structures based on unusual domains generated purposefully by these light‐mediated methods.