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Juvenile white sharks (Carcharodon carcharias) typically aggregate along coastal beaches; however, high levels of recruitment and shifting oceanographic conditions may be causing habitat use expansions. Telemetry data indicate increased habitat use at the Northern Channel Islands (California, USA) by juvenile white shark that may be in response to increased population density at aggregation locations, or anomalous oceanographic events that impact habitat use or expand available habitat. Findings illustrate the need for long‐term movement monitoring and understanding drivers of habitat use shifts and expansion to improve ecosystem management. [ABSTRACT FROM AUTHOR]

With the ripening of 3D printing technology and the discovery of a variety of printable materials, 3D‐printed vascular stents provide new treatment options for patients with angiocardiopathy. Bioresorbable stent not only combines the advantages of metallic stent and drug‐coated balloon, but also avoids the disadvantages of them. 3D printing is also an economical and efficient way to produce stents and makes it possible to construct complex structures. In this study, stents made from poly(l‐lactic acid) (PLLA), poly(ε‐caprolactone) (PCL) and poly(l‐lactide‐co‐caprolactone) (PLCL) were manufactured by 3D printing and evaluated for radial strength, crystallinity and molecular weight. PLCL copolymerized by different proportions of lactic acid and caprolactone showed different mechanical and degradation properties. This demonstrated the potential of 3D printing as a low‐cost and high throughput method for stent manufacturing. The PLLA and PLCL 95/5 stents had similar mechanical properties, whereas PLCL 85/15 and PCL stents both had relatively low radial strength. In general, PLCL 95/5 had a faster degradation rate than PLLA. These two materials were made into peripheral vascular bioresorbable scaffolds (BRS) and further studied by additional bench testing. PLCL 95/5 peripheral BRS had superior mechanical properties in terms of flexural/bending fatigue and compression resistance. [ABSTRACT FROM AUTHOR]

Stress urinary incontinence (SUI) impacts ~1/3 of women over age 50. Negative publicity around PP meshes used in pelvic prolapse repair drives the need for identifying alternative biomaterials for SUI repair. Our study evaluated in vivo response to collagen sling implanted in an ovine model. Electrocompacted collagen threads were filament wound as slings and crosslinked in genipin. Collagen slings were implanted suburethrally mimicking the transvaginal tape technique. Main study groups were: Collagen sling (n = 3, 6 months) and PP sling (n = 3, 6 months). Collagen sling was also tested at 3‐weeks (n = 1) to observe early‐stage tissue response and 1‐year (n = 2) to assess biomaterial longevity in a preliminary capacity. Collagen slings healed to a fibrous ligament texture at 6 months and maintained such texture to 1 year. Histological scoring indicated biocompatible responses to collagen slings with no adverse events. All study groups exhibited complete tissue ingrowth and interstitial de novo collagen deposition at all time points. Collagen threads induced orderly de novo collagen deposition that was aligned along long axes of threads. Tissue infiltrated collagen slings that were explanted at 6 and 12 months presented similar structural strength with native tissues such as vagina and fascia, and PP (Lynx) slings (p >.05). With the limitation of low number of animals per time point in hindsight, this preliminary study justifies evaluation of collagen slings in a larger sample size of animals, particularly to assess persistence of ligamentous tissue response over longer durations than 1‐year. [ABSTRACT FROM AUTHOR]

A female scalloped hammerhead shark (Sphyrna lewini) conducted a species record deep dive to 1240 m in coastal‐pelagic waters off Hawaii Island. This extends the deepest known depth range of the species by over 200 m (650 ft) and highlights the question of the extent to which deep‐diving activity is mediated by physiological constraints, such as temperature and oxygen availability. [ABSTRACT FROM AUTHOR]

Despite advancements in surgical techniques and materials for rotator cuff repair procedures, primary repair failures remain common. This study examines the use of electrochemically aligned collagen (ELAC) threads woven into biotextile scaffolds as grafts to repair critical infraspinatus tendon defects in New Zealand White rabbits. Three surgical treatment groups were evaluated: rabbits undergoing direct repair as operative controls, rabbits receiving ELAC scaffolds alone, and rabbits treated with mesenchymal stem cell (MSC)‐seeded ELAC scaffolds. In each animal, the intact, contralateral infraspinatus served as an internal positive control. Tendon–bone constructs were harvested after 3 months in vivo and outcome measures included biomechanical testing, histological staining, and immunohistochemical staining. Biomechanical testing revealed that maximum load‐bearing capacity was comparable between all groups, while MSC‐seeded scaffold repairs exhibited increased stiffness relative to non‐seeded scaffold repairs. Histological staining revealed robust collagen deposition around ELAC fibers and increased cellularity within the continuum of woven scaffolds as compared to native tendon. Immunohistochemical staining revealed presence of collagens I and III in all groups, but procollagen I and the tendon‐specific marker tenomodulin were only observed in seeded and non‐seeded ELAC scaffold repairs. Findings of this pilot study warrant continued investigation of ELAC biotextile scaffolds for repair of critically‐sized rotator cuff tendon defects. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1864–1876, 2019. [ABSTRACT FROM AUTHOR]

Abstract: The redistribution of species has emerged as one of the most pervasive impacts of anthropogenic climate warming, and presents many societal challenges. Understanding how temperature regulates species distributions is particularly important for mobile marine fauna such as sharks given their seemingly rapid responses to warming, and the socio‐political implications of human encounters with some dangerous species. The predictability of species distributions can potentially be improved by accounting for temperature's influence on performance, an elusive relationship for most large animals. We combined multi‐decadal catch data and bio‐logging to show that coastal abundance and swimming performance of tiger sharks Galeocerdo cuvier are both highest at ~22°C, suggesting thermal constraints on performance may regulate this species' distribution. Tiger sharks are responsible for a large proportion of shark bites on humans, and a focus of controversial control measures in several countries. The combination of distribution and performance data moves towards a mechanistic understanding of tiger shark's thermal niche, and delivers a simple yet powerful indicator for predicting the location and timing of their occurrences throughout coastlines. For example, tiger sharks are mostly caught at Australia's popular New South Wales beaches (i.e. near Sydney) in the warmest months, but our data suggest similar abundances will occur in winter and summer if annual sea surface temperatures increase by a further 1–2°C. [ABSTRACT FROM AUTHOR]

ABSTRACT The effects of different material surfaces on phenotypic expression in macrophages and foreign body giant cells (FBGC) were addressed using our in vitro system of interleukin (IL)-4-induced macrophage fusion and FBGC formation. Arginine-glycine-aspartate (RGD)-, vitronectin (VN)-, and chitosan (CH)-adsorbed cell culture polystyrene, carboxylated (C, negatively charged) polystyrene, and unmodified (PS, non-cell culture treated) polystyrene were compared for their abilities to support monocyte/macrophage adhesion and IL-4-induced macrophage fusion. Pooled whole cell lysates from four different donors were evaluated by immunoblotting for expression of selected components in monocytes, macrophages, and FBGC. In addition to RGD and VN as previously shown, we find that CH supports macrophage adhesion and FBGC formation, whereas C or PS support macrophage adhesion but do not permit macrophage fusion under otherwise identical conditions of IL-4 stimulation. Likewise, components related to macrophage fusion (CD206, CD98, CD147, CD13) are strongly expressed on RGD-, VN-, and CH-adsorbed surfaces but are greatly diminished or not detected on C or PS. Importantly, material surfaces also influence the FBGC phenotype itself, as demonstrated by strong differences in patterns of expression of HLA-DR, B7-2, B7-H1, and toll-like receptor (TLR)-2 on RGD, VN, and CH despite morphologic similarities between FBGC on these surfaces. Likewise, we observe differences in the expression of B7-2, α2-macroglobulin, TLR-2, and fascin-1 between mononuclear macrophages on C and PS. Collectively, these findings reveal the extent to which material surface chemistry influences macrophage/FBGC phenotype beyond evident morphological similarities or differences and identify CH as an FBGC-supportive substrate. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1380-1390, 2015. [ABSTRACT FROM AUTHOR]

A novel biofabrication modality, electrophoretic compaction with macromolecular alignment, is utilized to make collagen threads that mimic the native tendon's structure and mechanical properties. A device with kinematic electrodes is designed to fabricate collagen threads in continuous length. For the first time, a 3D-biotextile is woven purely from collagen. Mechanical properties and load-displacement behavior of the biotextile mimic those of the native tendon while presenting a porosity of 80%. The open pore network facilitates cell seeding across the continuum of the bioscaffold. Mesenchymal stem cells (MSCs) seeded in the woven scaffold undergo tenogenic differentiation in the absence of growth factors and synthesize a matrix that is positive for tenomodulin, COMP and type I collagen. Up-regulation of tenomodulin, a tendon specific marker, is 11.6 ± 3.5 fold, COMP is up-regulated 16.7 ± 5.5 fold, and Col I is up-regulated 6.9 ± 2.7 fold greater on ELAC threads when compared to randomly oriented collagen gels. These results demonstrate that a bioscaffold woven using collagen threads with densely compacted and anisotropically aligned substrate texture stimulates tenogenesis topographically, rendering the electrochemically aligned collagen as a promising candidate for functional repair of tendons and ligaments. [ABSTRACT FROM AUTHOR]

In previous studies that explored the influence of cytokines on foreign body giant cell (FBGC) formation, we focused on interleukin (IL)−4 and IL-13, each of which was discovered to induce macrophage fusion leading to FBGC formation in vitro. Two correlative in vivo studies also confirmed that IL-4 plays a role in FBGC formation on implanted biomaterials, but that T lymphocytes are not the source of IL-4 or other cytokines that support this process. The present study focused on identification of the cellular source of macrophage fusion-inducing cytokines, including natural killer (NK) or NKT lymphocytes and mast cells using mouse models genetically deficient in each of these cell types, as well as IL-4 receptor alpha(IL-4Rα)-deficient and severe combined immunodeficient (SCID) mice. Polyetherurethane (PEU) and polyethylene terephthalate (PET) polymers were subcutaneously implanted and retrieved after 14, 21, or 28 days. FBGC formation was evaluated using quantitative and qualitative data from retrieved polymer surfaces. Both types of data indicate that, compared to normal control mice, neither NK or NKT lymphocytes nor mast cells are required for FBGC formation. Furthermore, FBGC formation on biomaterials can proceed in IL-4Rα-deficient and in SCID mice. Similar conclusions were made regarding FBGC formation on both PEU and PET biomaterials. These data suggest that other sources of IL-4/IL-13 and/or additional macrophage fusion-inducing cytokines can mediate FBGC formation on implanted biomaterials, or that, in the absence of normal primary pathways, FBGC formation is nevertheless supported by redundant innate mechanisms. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2017-2023, 2014. [ABSTRACT FROM AUTHOR]

Coating of various synthetic, absorbable, and biologic meshes with mesenchymal stem cells (MSCs) and fibroblasts was analyzed qualitatively and quantitatively. Five hernia meshes-light weight monofilament polypropylene (Soft Mesh), polyester (Parietex-TET), polylactide composite (TIGR), heavy weight monofilament polypropylene (Marlex), and porcine dermal collagen (Strattice)-were coated with three cell lines: human dermal fibroblasts (HFs), rat kidney fibroblasts (NRKs), and rat MSCs. Cell densities were determined at different time points. Samples also underwent histology and transmission electron microscopic (TEM) analyses. It required HFs 3 weeks to cover the entire mesh, while only 2 weeks for NRKs and MSCs to do so. MSCs had no preference for any of the meshes and produced the highest cell densities on Parietex and TIGR. Substrate-preference accounted for the significantly lower fibroblast densities on TIGR than Parietex. Fibroblasts failed to coat Marlex. Strattice, which had the least surface area, generated comparable cell densities to Parietex. Both histology and TEM confirmed cell coating of mesh surface. Various prosthetics can be coated by certain cell strains. Both mesh composition and cell preference dramatically influence the coating process. This methodology provides foundation for novel avenues of modulation of host response to various modern synthetic and biologic meshes. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 797-805, 2014. [ABSTRACT FROM AUTHOR]

Biomaterial-centered infections are initiated by adhesion of bacteria to an implant, followed by colonization and mature biofilm formation. Staphylococcus epidermidis is commonly identified as the cause of these device-centered infections. This study used an in vitro model to evaluate temporal changes in the expression of genes- icaADBC, agrBDCA, aap, and atle-that have been identified to play a role in the pathogenesis of S. epidermidis infections. Real-time reverse transcription-polymerase chain reaction was used to determine changes in gene expression from S epidermidis biofilm grown on polyurethanes (Elasthane 80A, hydrophobic) modified with polyethylene oxide (Elasthane 80A-6PEO, hydrophilic) and fluorocarbon (Elasthane 80A-6F, hydrophobic). In vitro expression of the ica locus, which is involved in initial adhesion and intracellular aggregation, increased up to 100-fold from 2 to 48 h, whereas gene expression for autolysin AtlE decreased slightly from 2 to 12 h, followed by a 10-fold increase by 48 h. Upregulation of the aap gene associated with bacterial accumulation and the agr quorum-sensing system was observed during biofilm formation over 48 h. In addition, no correlation was observed between S. epidermidis gene expression and biomaterial surface chemistry. This study used an in vitro model to demonstrate that enhanced expression of the atle, aap, agr, and ica genes plays an important role in initial foreign body colonization and potentially in the establishment of a device-associated infection. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2863-2869, 2012. [ABSTRACT FROM AUTHOR]

This study reports on the use of a fibrinogen-derived peptide for the specific targeting and delivery of vancomycin to S taphylococcus epidermidis biofilms. One method by which S. epidermidis initially adheres to biomaterials uses the plasma protein fibrinogen as an intermediary, where the S. epidermidis surface protein SdrG binds to a short amino acid sequence near the amino terminus of the Bβ chain of fibrinogen. We mimicked this binding interaction and demonstrated the use of a synthetic fibrinogen-based β6-20 peptide to target and deliver vancomycin to S. epidermidis in vitro. The β6-20 peptide was synthesized and labeled with a Nanogold probe, and its targeting capabilities were examined through the use of scanning electron microscopy. The Nanogold component was then replaced by vancomycin, utilizing a flexible, variable length poly(ethylene glycol) linker between the peptide and antibiotic to create the targeted vancomycin products, β6-20-PEG x-VAN. Initial binding to surface adherent S. epidermidis was increased in a concentration-dependent manner relative to vancomycin for all equivalent concentrations ≥4 μg/mL, with targeted vancomycin content up to 22.9 times that of vancomycin alone. Retention of the targeted antibiotics was measured after an additional 24-h incubation period, revealing levels 1.3 times that of vancomycin. The results demonstrate the improved targeting and retention of vancomycin within a biofilm due to the incorporation of a specific targeting motif. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 2517-2525, 2012. [ABSTRACT FROM AUTHOR]

The C-terminal cytoplasmic tails of claudins are likely sites for interaction with proteins that regulate their function. We performed a yeast two-hybrid screen with the tail of human claudin-2 against a human kidney cDNA library and identified interactions with the PDZ3 domain of ZO-2 as well as ubiquitin-conjugating enzyme E2I (SUMO ligase-1) and E3 SUMO-protein ligase PIAS; the first is a predicted interaction, while the latter two are novel and suggest that claudin-2 is a substrate for SUMOylation. Using an in vitro SUMOylation assay, we identified K218 as a conjugation site on claudin-2; mutation of that lysine to arginine blocked SUMOylation. Stable expression of inducible GFP-SUMO-1 in MDCK cells resulted in decreased levels of claudin-2 protein by immunoblot and decreased claudin-2 membrane expression by immunofluorescence microscopy. We conclude that the cellular levels of claudin-2 may be modulated by SUMOylation, warranting further investigation of cellular pathways that regulate this modification in vivo. [ABSTRACT FROM AUTHOR]

Treatment of epithelial and endothelial cells with proinflammatory cytokines can stimulate tight junction protein endocytosis, with associated loss of physiologic barrier function. In some instances, the endocytic scaffolding protein, caveolin-1, has been implicated in the cytokine-dependent retrieval of the tight junction proteins occludin and claudins. How caveolin-1 interacts with these proteins, however, remains undefined. Using co-immunoprecipitation assays, we found that caveolin-1 separately interacts with claudin-2 and occludin, but not with ZO-1, ZO-2, or claudin-4. Further, we found that the interactions of caveolin-1 with claudin-2 and occludin were not disrupted by cholesterol removal, suggesting that they were not dependent on co-localization to cholesterol-rich lipid rafts. Co-immunoprecipitation of caveolin-1 with chimeras between claudin-2 and -4 indicated that the C-terminal cytoplasmic domain of claudin-2 is required for association with caveolin-1; similar analysis showed that the ZO-1 binding region of occludin is not required for its interaction with caveolin-1. The finding that caveolin-1 interacts with claudin-2 and occludin, but not with claudin-4 or ZO-1, suggests a potential mechanism for selective retrieval of tight junction components. [ABSTRACT FROM AUTHOR]

This study reports the use of a targeted cationic peptide with the ability to disrupt Staphylococcus epidermidis biofilm formation. Complications due to nosocomial infections of implanted medical devices pose a significant health risk to patients, with Staphylococcus epidermidis often implicated in the case of blood-contacting biomaterials. S. epidermidis virulence relies mainly on its ability to form a biofilm, the main component of which is polysaccharide intercellular adhesin (PIA). We utilized the synthetic β6-20 peptide, known to specifically bind S. epidermidis, in order to deliver a cationic polylysine peptide (G3K6) to the bacterial surface and disrupt the charge-charge interactions needed for PIA retention and biofilm stability. The effects of the β6-20-G3K6 peptide on biofilm formation were assessed using optical density, fluorescently labeled wheat germ agglutinin, nucleic acid stain (SYTO 9), and a metabolic assay (XTT, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2 H-tetrazolium-5-carboxanilide inner salt). Biofilms formed in the presence of β6-20-G3K6 peptide (100 μ M) resulted in a 37.9% reduction in PIA content and a 17.5% reduction of adherent bacteria relative to biofilms grown in the absence of peptide. These studies demonstrate the targeting ability of the β6-20 peptide towards biomaterial-adherent S. epidermidis, and highlight the potential for disrupting the early stages of biofilm formation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012. [ABSTRACT FROM AUTHOR]

Carriers for bone morphogenetic protein-2 (BMP-2) used in clinical practice still suffer from limitations such as insufficient protein retention. In addition, there is a clinical need for injectable carriers. The main objective of this study was to assess bone forming ability of rhBMP-2 combined either with chitosan hydrogel (rhBMP-2/CH) or chitosan hydrogel containing β-tricalcium phosphate (β-TCP) (rhBMP-2/CH/TCP). Formulations were first compared in a rat ectopic intramuscular bone formation model, and the optimal formulation was further evaluated in healing of 15-mm critical size defect in the radius of a rabbit. Three weeks after injection ectopically formed bone was analyzed by microcomputerized tomography (micro-CT) and histology. Significantly higher (4.7-fold) mineralized bone formation was observed in the rhBMP-2/CH/TCP group compared to rhBMP-2/CH group. In a pilot study, defect in a rabbit radius treated with rhBMP-2/CH/TCP showed incomplete regeneration at 8 weeks with composite leakage from the defect, indicating the need for formulation refinement when segmental defect repair is foreseen. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2010. [ABSTRACT FROM AUTHOR]

Previous in vitro studies in our laboratory have shown that lymphocytes can influence macrophage adhesion and fusion on biomaterial surfaces. However, few studies have evaluated how material adherent macrophages can influence lymphocyte behavior, specifically T cells. In this study, we cultured human peripheral blood mononuclear cells from healthy donors on three synthetic nonbiodegradable biomedical polymers: elasthane 80A (PEU), silicone rubber (SR), or polyethylene terephthalate (PET) and tissue culture polystyrene (TCPS). Upregulation of T cell surface activation markers (CD69 and CD25), lymphocyte proliferation, and interleukin‐2 (IL‐2) and interferon‐γ (IFNγ) concentrations were evaluated by flow cytometry, carboxy‐fluorescein diacetate, succinimydyl ester (CFSE) incorporation, and multiplex cytokine immunoassay, respectively, to assess T cell activation. Following 3 and 7 days of culture, CD4+ helper T cells from cultures of any of the material groups did not express the activation markers CD69 and CD25 and lymphocyte proliferation was not present. IL‐2 and IFNγ levels were produced, but dependent on donor. These data indicate that T cells are not activated in response to clinically relevant synthetic biomaterials. The data also suggest that lymphocyte subsets exclusive of T cells are the source of the lymphokines, IL‐2 and IFN‐γ, in certain donors. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010 [ABSTRACT FROM AUTHOR]

Biofilm formation plays an integral role in catheter-associated bloodstream infections caused by Candida albicans. Biofilms formed on catheters placed intravenously are exposed to shear stress caused by blood flow. In this study, we investigated whether shear stress affects the ability of C. albicans to form biofilms. Candida biofilms were formed on catheter discs and exposed to physiological levels of shear stress using a rotating disc system (RDS). Control biofilms were grown under conditions of no flow. Tetrazolium (XTT) assay and dry weight (DW) measurements were used to quantify metabolic activity and biofilm mass respectively. Confocal scanning laser microscopy (CSLM) was used to evaluate architecture and biofilm thickness. After 90 min, cells attached under no-flow exhibited significantly greater XTT activity and DW than those under shear. However, by 24 h, biofilms formed under both conditions had similar XTT activities and DW. Interestingly, thickness of biofilms formed under no-flow was significantly greater after 24 h than of those formed under shear stress, demonstrating that shear exposure results in thinner, but denser biofilms. These studies suggest that biofilm architecture is modulated by shear in a phase-dependent manner. [ABSTRACT FROM AUTHOR]

The integrity of the tight junction barrier in epithelial and endothelial cells is critical to human health, but we still lack a detailed mechanistic knowledge of how the barrier is formed during development or responds to pathological and pharmacological insults. This limits our understanding of barrier dysfunction in disease and slows the development of therapeutic strategies. Recent studies confirm the long-maintained but previously unsupported view that the zonula occludens (ZO) proteins ZO-1 and ZO-2 are critical determinants of barrier formation. However, ZO proteins can also be components of adherens junctions, and recent studies suggest that ZO proteins may also promote the assembly and function of these junctions during epithelial morphogenesis. We review these studies and outline several recent observations that suggest that one role of ZO proteins is to regulate cytoskeletal dynamics at cell junctions. Finally, we propose a model by which the functional activities of ZO proteins in the adherens junction and tight junction are differentiated by a novel regulatory motif known as the U6 or acidic motif. [ABSTRACT FROM AUTHOR]

Objectives To examine the effectiveness in screening for triploidy at 11 weeks to 13 weeks and 6 days of gestation by the combined use of the risk algorithms for trisomies 21, 18 and 13 based on maternal age, fetal nuchal translucency (NT) thickness, fetal heart rate (FHR) and maternal serum free β-hCG and PAPP-A. Methods Prospective screening for trisomy 21, including 56 376 normal singleton pregnancies and 31 cases with triploidy (24 digynic and 7 diandric). Patient-specific risks for trisomies 21, 18 and 13 were calculated by multiplying the age related risk for trisomies 21, 18 and 13 with the likelihood ratio (LR) for fetal NT and with a combined LR for FHR, free β-hCG and PAPP-A, respectively. Detection rates (DRs) and false positive rates (FPRs) for triploidy were calculated by taking the proportion with risks above a given risk threshold and standardized for maternal age according to the distribution of pregnancies in England and Wales in 2000 to 2002. Results In digynic triploidy, free β-hCG was 0.16 (range 0.02-0.95) MoM and PAPP-A was 0.06 (range 0.02-0.47) MoM and the respective values for diandric triploidy were 8.74 (range 2.83-47.0) and 0.74 (range 0.32-1.51) MoM. Use of the trisomy 21 algorithm identified 5 of the 7 diandric cases and 3 of the 24 digynic ones at a 3% FPR. Combined use of the risk algorithms for trisomies 18 and 13 identified 20 of the 24 cases with the digynic triploidy at the FPR of 0.2%. When screen positivity was defined by a 3% FPR using the algorithm for trisomy 21 and an additional 0.2% FPR using the algorithms for trisomies 18 and 13, the total FPR was 3.1% and the DR was 84%. Conclusions A beneficial side-effect of first trimester combined screening for trisomies is the detection of a high proportion of fetuses with triploidy. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The cell surface proteoglycan, syndecan-1, is essential for normal epithelial morphology and function. Syndecan-1 is selectively localized to the basolateral domain of polarized epithelial cells and interacts with cytosolic PDZ (PSD-95, discs large, ZO-1) domain-containing proteins. Here, we show that the polarity of syndecan-1 is determined by its type II PDZ-binding motif. Mutations within the PDZ-binding motif lead to the mislocalization of syndecan-1 to the apical surface. In contrast to previous examples, however, PDZ-binding motif-dependent polarity is not determined by retention at the basolateral surface but rather by polarized sorting prior to syndecan-1’s arrival at the plasma membrane. Although none of the four known PDZ-binding partners of syndecan-1 appears to control basolateral localization, our results show that the PDZ-binding motif of syndecan-1 is decoded along the biosynthetic pathway establishing a potential role for PDZ-mediated interactions in polarized sorting. [ABSTRACT FROM AUTHOR]

Antibody‐based cell microarrays may serve as a high‐throughput diagnostic tool that requires precise surface design providing high biological specificity, high reliability, and high validity. A fundamental study on the quantitative evaluation of immunophenotyping using a cell microarray on which antibodies specific to cluster of differentiation (CD) antigens of blood cells are fixed was performed. The microarray, which was prepared by photomicropatterning self‐assembled monolayers of alkanethiols, consisted of carboxyl group (3‐mercaptopropionic acid)‐packed domains regularly distributed in the methyl group (1‐dodecanethiol)‐packed matrix phase. This was verified by X‐ray photoelectron spectroscopy and water wettability measurements. The patterned carboxylated domains of 1.0 mm or 0.2 mm diameter were covalently fixed with the anti‐CD4 or anti‐CD8 antibody by coupling reaction using a water‐soluble carbodiimide and hydroxysuccinimide. Precision antibody fixation at almost complete conversion was verified by confocal laser scanning microscopy coupled with a specific dye staining technique. Peripheral blood mononuclear cells expressing CD4 or CD8 antigen, respectively, adhered on the anti‐CD4 or anti‐CD8 antibody‐fixed domains of the microarray at a very high specificity, which was verified with flow cytometric analysis and an antibody‐coated magnetic‐bead‐based cell isolation technique. The CD4/CD8 subset ratios determined using the antibody‐fixed microarrays were very close to those obtained by flow cytometric analysis. These results indicate that microarrays, on which antibodies specific to cell surface antigens are covalently fixed, provide a solid basis of the high‐throughput quantitative evaluation of immunophenotyping in medical diagnosis. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [ABSTRACT FROM AUTHOR]

The formation of biofilm, a structured community of bacteria enclosed in slime, is a significant virulence factor in medical‐device‐centered infection. The development of cardiovascular device infection can be separated into two phases: initial bacterial adhesion and aggregation, followed by proliferation and production of slime. It is possible to modulate the adhesion and biofilm formation of Staphylococcus epidermidis, a commensal skin bacterium commonly found on infected medical devices, through biomaterial surface chemistry. This study examines bacterial adhesion and biofilm formation on surface‐modified polyethylene terephthalate (PET), including surfaces with varying hydrophilic, hydrophobic, and ionic character. Bacterial adhesion and biofilm formation were observed over 48 hours in phosphate‐buffered saline (PBS) and 20% pooled human serum. The hydrophilic surface (PAAm) had significantly less nonspecific adhesion of bacteria than that in the control (PET) and other surfaces, when cultured in PBS (P < 0.0001). Charged surfaces, both anionic and cationic, had increased adhesion and aggregation of bacteria in comparison with the control (PET) in the presence of serum proteins over 24 hours (P < 0.0001). Bacteria cultured in serum on the charged surfaces did not have significantly different amounts of biofilm formation compared with that of the control (PET) surface after 48 hours. This study showed that biomaterial surface chemistry characteristics impact initial adhesion and aggregation of S. epidermidis on biomaterials. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006 [ABSTRACT FROM AUTHOR]

In this study, a fatty acid urethane derivative of dehydroepiandrosterone (DHEA) was synthesized and evaluated as a polyurethane additive to increase long-term biostability. The modification was hypothesized to reduce the water solubility of the DHEA and physically anchor the additive in the polyurethane during implantation. Polyurethane film weight loss in water as a function of time was studied to determine the polymer retention of the modified DHEA. The polyurethane film with unmodified DHEA had significant weight loss in the first day (10%) that was previously correlated to rapid leaching of the additive. The polyurethane film with modified DHEA had significantly less weight loss at all time points indicating improved polymer retention. The effect of the modified DHEA additive on the biostability of a poly(ether urethane urea) was examined after 5 weeks of subcutaneous implantation in Sprague- Dawley rats. Optical micrographs and infrared analysis of the specimens indicated that the modified DHEA bloomed to the surface of the film forming a crystalline surface layer approximately 10--15 microns thick. After explantation, this surface layer was intact without measurable differences in surface chemistry as monitored by attenuated total reflectance- Fourier transform infrared spectroscopy. There was no evidence of degradation of the polyurethane underneath the modified DHEA surface layer as compared with the polyurethane control. We have concluded that the modified DHEA self-assembled into a protective surface coating that inhibited degradation of the polyurethane. The roughness of the modified DHEA surface layer prevented adherent cell analysis to determine if the additive retained the ability to down-regulate macrophage activity. Subsequent studies will investigate the ability of surface-modifying additives to modulate cellular respiratory bursts in addition to the formation of an impermeable barrier. This bimodal approach to improving biostability holds great promise in the field of polyurethane biomaterials. [ABSTRACT FROM AUTHOR]

The goal of this study was to determine whether antioxidant therapy with vitamin E would alter the rate of vascular access complications or other macrovascular complications in hemodialysis (HD) patients. A secondary goal of the study was to explore the relationship between baseline pretreatment markers of oxidative stress (the advanced glycation end product pentosidine and basal levels of vitamin Eα andγ) and the subsequent development of access failure. Thirty-five stable patients treated by HD were recruited for the study. Patients were provided with vitamin E (800 IU) or placebo capsules to be taken daily. Clinical variables, vascular access function (flow meter access flow measurements), and circulating blood markers were obtained initially and every 3 months throughout the study. Vitamin Eα levels rose in treated patients from 12.7 ± 4.4 to 25.1 ± 15.1 µg/mL at 3 months and 28.6 ± 14.8 µg/mL at 6 months. Vitamin Eγ levels fell in treated patients from 3.9 ± 1.7 to 2.3 ± 1.5 µg/mL at 3 months and 1.7 µg/mL at 6 months. Patients who subsequently developed repeated thrombotic vascular access events were characterized by higher baseline pentosidine content of circulating proteins. Patients who developed a myocardial infarction had higher pentosidine, lower vitamin Eα, and much lower vitamin Eγ than patients who did not develop thrombotic events. These findings lead to the speculation that the anti-inflammatory effects of vitamin Eγ may play a more important role in thrombotic vascular events than the antioxidant effects of vitamin Eα. Additional studies of these interactions are in progress. [ABSTRACT FROM AUTHOR]

Aseptic loosening of orthopaedic implants is thought to be primarily due to stimulation of cytokine production by wear particles from the implants. The cytokines increase osteoclast differentiation, leading to osteolysis and implant loosening. Accumulating evidence indicates that adherent endotoxin mediates the biological responses induced by the wear particles. One mechanism by which adherent endotoxin may act is by increasing phagocytosis of the wear particles. To test this hypothesis, the effect of adherent endotoxin on phagocytosis of titanium particles was determined. First, we developed reliable confocal and fluorescence microscopy methods to examine both the attachment and internalization steps of phagocytosis. Use of these methods showed that adherent endotoxin does not detectably alter the rate or the extent of phagocytosis of titanium particles by RAW 264.7 cells. Despite this lack of an effect on phagocytosis, adherent endotoxin dramatically increases the ability of RAW 264.7 cells to produce TNF-α and induce osteoclast differentiation. Thus, adherent endotoxin mediates these biological responses by a mechanism that does not rely on increased phagocytosis. These results also demonstrate that phagocytosis is not sufficient to induce cytokine production and osteoclast differentiation but do not rule out the possibility that phagocytosis is required for induction of these responses by titanium particles with adherent endotoxin. [Copyright &y& Elsevier]

The celestial sources observed by geodetic very‐long‐baseline interferometry (VLBI), most of which are quasars, are resolved—they have a finite angular size as measured by the interferometer—yet modern geodetic VLBI analysis techniques still treat these sources as if they are point‐like. The errors introduced by source structure, the angular distribution of emission, have traditionally been believed to be a small fraction of the total measurement error budget. We analyzed the VLBI data of the CONT14 continuous observing campaign using standard geodetic and imaging techniques, along with an analysis of closures, combinations of interferometric measurements where the error contributions from station‐based effects such as tropospheric and ionospheric errors, clock and cable length errors, station position errors, and so on, cancel exactly, leaving only nonclosing errors, principally source structure and measurement noise. Our statistical analysis of the closure information, based on actual VLBI observations revealed that nearly half (40%) of the total geodetic VLBI error budget (in terms of variance) in CONT14 came from source‐structure effects, nearly the same variance as all station‐based error sources (43%). The remaining error due to other nonsource‐structure, nonclosing errors is also significant (17%). Previous studies, which were primarily simulation‐based, did not account for the full range of effects of source structure on real measurements. Source structure is a major contributor to errors in geodetic VLBI, and source structure must be taken into account in the entire VLBI operational chain, from scheduling to analysis, in order to mitigate its effects on astrometric and geodetic measurements. Key Points: Source‐structure errors in geodetic VLBI were determined from actual IVS observations, not simulationsSource‐structure and measurement noise were measured using closure relationshipsSource‐structure errors in CONT14 are approximately as large as all station‐based errors combined [ABSTRACT FROM AUTHOR]

Barrett's esophagus (BE) is a lesion characterized by specialized columnar epithelium lining the distal esophagus. It develops in subjects with acid reflux disease as replacement for destroyed esophageal stratified squamous epithelium (SqE) -- presumably because it is more acid resistant than SqE. How BE resists acid injury is complex but one means may involve alteration in the structure and function of its tight junctions. To address this question, expression profiles were performed for 21 claudin genes by quantitative RT-PCR and highly expressed claudin proteins immunolocalized by fluorescence microscopy on endoscopic biopsies from BE and from healthy SqE from subjects without esophageal disease. The results showed that all 21 claudins were expressed in BE while 19 claudins were expressed in SqE. Further, claudins 3, 4, 12, 15, 18 and 23 were overexpressed in BE compared to SqE, and claudin 18 notable for being both the most highly expressed in BE and absent in SqE. Immunolocalization studies in BE reveled that several claudins were localized to the tight junctions including 4, 7, 8, 10, 15, and, importantly, 18. Given the uniqueness of claudin 18 in BE, this claudin was expressed in MDCK II cells and shown to selectively increase junctional resistance to cations (Na+) compared to standard MDCK II cells. These results suggest that the alterations in tight junction structure and function in BE is one means for its greater acid resistance than SqE. [ABSTRACT FROM AUTHOR]

Tight junctions (TJ) create charge and size-selective barriers for solutes in the paracellular pathway. The large claudin family determines ionic selectivity, however, the basis of size discrimination remains unknown. The purpose of our study was to compare the TJ size selectivity for uncharged solutes among several cell types and to determine whether claudins influence this parameter. We simultaneously determined the permeability (Papp) for a series of 22 polyethylene glycols (PEG) ranging in radius from ≈ 2.5-7 Å across cultured monolayers of renal tubular (LLC-PK1, MDCK II, MDCK C7), and intestinal (Caco-2) cells and porcine ileum. PEGs were quantified by post-flux labeling with 1-napthylisocyanate followed by HPLC-fluorescence detection. Papp showed a size discrimination extrapolating to an apparent pore radius of about 4 Å in all cell types and intestine. However, the number of pores varied widely among cell types and was unrelated to transepithelial electrical resistance (TEER). A second smaller capacity pathway was size-independent. Inducible expression of claudin-2 or 18, but not occludin, increased the number of small pores in MDCK II cells. Although claudins have previously been shown to regulate paracellular movement of charged ions and thus TEER, these new results are consistent with the idea that these same claudin pores also form a high capacity pathway for small uncharged solutes. [ABSTRACT FROM AUTHOR]