Rapid Photocrosslinking of Silk Hydrogels with High Cell Density and Enhanced Shape Fidelity

Silk fibroin hydrogels crosslinked through di-tyrosine bonds are clear, elastomeric constructs with immense potential in regenerative medicine applications. In this study, demonstrated is a new visible light-mediated photoredox system for di-tyrosine bond formation in silk fibroin that overcomes major limitations of current conventional enzymatic-based crosslinking. This photomediated system rapidly crosslinks silk fibroin (80%). The photocrosslinked silk hydrogels present more stable mechanical properties which do not undergo spontaneous transition to stiff, β-sheet-rich networks typically seen for enzymatically crosslinked systems. These hydrogels also support long-term culture of human articular chondrocytes, with excellent cartilage tissue formation. This system also facilitates the first demonstration of biofabrication of silk fibroin constructs in the absence of chemical modification of the protein structure or rheological additives. Cell-laden constructs with complex, ordered, graduated architectures, and high resolution (40 µm) are fabricated using the photocrosslinking system, which cannot be achieved using the enzymatic crosslinking system. Taken together, this work demonstrates the immense potential of a new crosslinking approach for fabrication of elastomeric silk hydrogels with applications in biofabrication and tissue regeneration

Mix-and-Match System for the Enzymatic Synthesis of Enantiopure Glycerol-3-Phosphate-Containing Capsule Polymer Backbones from Actinobacillus pleuropneumoniae, Neisseria meningitidis, and Bibersteinia trehalosi

Capsule polymers are crucial virulence factors of pathogenic bacteria and are used as antigens in glycoconjugate vaccine formulations. Some Gram-negative pathogens express poly(glycosylglycerol phosphate) capsule polymers that resemble Gram-positive wall teichoic acids and are synthesized by TagF-like capsule polymerases. So far, the biotechnological use of these enzymes for vaccine developmental studies was restricted by the unavailability of enantiopure CDP-glycerol, one of the donor substrates required for polymer assembly. Here, we use CTP:glycerol-phosphate cytidylyltransferases (GCTs) and TagF-like polymerases to synthesize the poly(glycosylglycerol phosphate) capsule polymer backbones of the porcine pathogen Actinobacillus pleuropneumoniae, serotypes 3 and 7 (App3 and App7). GCT activity was confirmed by high-performance liquid chromatography, and polymers were analyzed using comprehensive nuclear magnetic resonance studies. Solid-phase synthesis protocols were established to allow potential scale-up of polymer production. In addition, one-pot reactions exploiting glycerol-kinase allowed us to start the reaction from inexpensive, widely available substrates. Finally, this study highlights that multidomain TagF-like polymerases can be transformed by mutagenesis of active site residues into single-action transferases, which in turn can act in trans to build-up structurally new polymers. Overall, our protocols provide enantiopure, nature-identical capsule polymer backbones from App2, App3, App7, App9, and App11, Neisseria meningitidis serogroup H, and Bibersteinia trehalosi serotypes T3 and T15

Silk fibroin photo-lyogels containing microchannels as a biomaterial platform for: In situ tissue engineering

The biophysical properties of biomaterials are key to directing the biological responses and biomaterial integration and function in in situ tissue engineering approaches. We present silk photo-lyogels, a biomaterial format fabricated using a new combinatorial approach involving photo-initiated crosslinking of silk fibroin via di-tyrosine bonds followed by lyophilization to generate 3D, porous lyogels showing physical properties distinct to those of lyophilized silk sponges or silk hydrogels. This fabrication approach allowed introduction of microchannels into 3D constructs via biofabrication approaches involving silk crosslinking around an array of 3D printed photocurable resin pillars to generate parallel channels or around a 3D printed sacrificial thermosensitive gel to generate interconnected channels in a rapid manner and without the need for chemical modification of silk fibroin. The presence of interconnected microchannels significantly improved migration of endothelial cells into 3D photo-lyogels in vitro, and tissue infiltration, photo-lyogel integration, and vascularization when implanted in vivo in a mouse subcutaneous model. Taken together, these findings demonstrate the feasibility and utility of a new combinatorial fabrication approach for generation of silk biomaterials that support cell interactions and implant integration for in situ tissue engineering approaches

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

A comparative, double-blind study of Tenoxicam-Pyroxicam in the treatment of extraarticular rheumatism [ESTUDIO COMPARATIVO DOBLE-CIEGO TENOXICAM-PIROXICAM PARA EL TRATEMIENTO DEL REUMATISMO EXTRAARTICULAR]

[No abstract available

Dermatomyositis exacerbated by abdominal Marlex® mesh implantation: Adjuvant effect?

We describe a 35-year-old woman with dermatomyositis, who four months after implantation of abdominal Marlex® mesh, developed a severe exacerbation of her disease with muscle weakness, elevated acute-phase reactants, a high level of muscle enzymes, and the appearance of dermal lesions with calcinosis. The Marlex® mesh implant may have triggered the flare-up of her underlying autoimmune disorder

Bone turnover markers and bone mineral density in children with haemophilia

During childhood growth, bone undergoes modelling involving separate osteoblastic and osteoclastic processes. Markers of bone turnover circulate at high concentrations, parallel the childhood growth curve and correlate with height velocity. The aim of this study was to compare serum markers of bone turnover in children with haemophilia and normal bone mineral density (BMD) vs. those with low BMD. In a cross-sectional study, 69 children with haemophilia were evaluated, 45 children with normal spine BMD vs. 24 with low BMD. Lumbar spine BMD was determined using dual X-ray absorptiometry and Z-scores were calculated. Serum samples of markers of bone turnover, osteocalcin (bone formation) and C-telopeptide of type I collagen (bone resorption) were measured using ELISA. The mean BMD (g cm -2) in the normal group was 0.656�0.15 vs. 0.558�0.12 in those with low BMD (P=0.007), osteocalcin levels in children with normal BMD were 9.29�4.97 vs. 7.06�2.17ng ?L -1 in the low BMD group (P=0.012). C-telopeptide levels in the normal group were 1.06�1.4 vs. 0.74�0.3ng mL -1 in the low BMD group (P=0.169). Our results showed that low osteocalcin levels predominated in the group with low BMD, which indicates a diminished osteoblastic bone formation activity while there were no differences with regard to bone resorption markers. Moreover, osteocalcin levels explain 10% of the variation of lumbar spine Z-score. � 2010 Blackwell Publishing Ltd

Fourier transform methods applied to an optical heterodyne profilometer

Background. The Functional Independence Score in Hemophilia (FISH) is a performance-based assessment tool used to measure the patients functional ability so far only used in patients with severe hemophilia. Its aim is to determine if FISH is useful in patients with mild and moderate disease. Procedure. In a cross-sectional study 90 children 60 hemophilic and 30 sex-, race-, and age-matched healthy males were assessed. Patients between 5 and 16 years of age were selected each patient was evaluated in seven activities under three categories: self-care (grooming and eating, bathing, and dressing), transfers (chair and squat), and locomotion (walking and step climbing). Each activity was graded from 1 to 4 according to the amount of assistance required to perform the activity with total scores ranging from 7 to 28. Results. As a whole, the mean age of the patients was 10.0 3.4 years with a mean FISH of 25.8 3.6 (range 15-28). There were no differences in the FISH between healthy males and patients with mild hemophilia; however, the score was significantly higher in patients with mild hemophilia (28 0) than patients with moderate (26.2 2.5; P=0.004) or severe hemophilia (24.0 4.7; P=0.0006). The most affected activities were squatting, walking, and step climbing. Conclusions. A significant decrease in functional ability was demonstrated according to the severity of hemophilia, especially for those activities involving weight-bearing demands like locomotion and step climbing. Of seven activities evaluated, changes were observed in the groupwith moderate and severe hemophilia, but no changes detected in patients with mild disease. " 2009 Wiley-Liss, Inc.",,,,,,"10.1002/pbc.22291",,,"http://hdl.handle.net/20.500.12104/41629","http://www.scopus.com/inward/record.url?eid=2-s2.0-76749104679&partnerID=40&md5=126e92e98ee68fa8dae84e4b75469e19",,,,,,"3",,"Pediatric Blood and Cancer",,"39

Expression of interleukin-1?, tumor necrosis factor ?, interleukins-6, -10 and -4, and metalloproteases by freshly isolated mononuclear cells from early never-treated and non-acute treated rheumatoid arthritis patients

Objective: To determine IL-1?, TNF?, IL-6, IL-4, IL-10, MMP-1, MMP-3 and MMP-13 expression by freshly isolated peripheral blood (PBMC) and synovial fluid mononuclear cells (SFMC) in early, never-treated (ENT-RA) and non-acute, treated rheumatoid arthritis (NAT-RA) patients. To elucidate whether excessive or inadequate interleukin (IL) and metalloprotease (MMP) expression is influenced by the disease duration. Methods: Fourteen RA patients, 7 with early RA ( 2 years of evolution) treated with disease-modifying antirheumatic drugs, were studied by ELISA and quantitative and semiquantitative RT-PCR. A group of 14 healthy subjects matched for sex and age was included. Results: No statistically significant difference in the protein or transcript levels for the cytokines of interest was found between the ENT-RA and NAT-RA groups. The cytokine mRNA expression by freshly isolated PBMC and SFMC in both groups was as follows: IL-1? > TNF? > IL-10 > IL-6, with no mRNA IL-4 expression. In contrast, cytokine serum levels in ENT-RA and NAT-RA patients were detected in inverse order as follows: IL-6 > IL-10, while IL-1?, TNF? and IL-4 were undetectable. MMP-3 mRNA expression by the PBMC of NAT-RA patients was statistically different to that in ENT-RA patients. Similar levels of mRNA expression of MMP-1, MMP-3 and MMP-13 by the PBMC and SFMC in both RA groups were observed. Conclusions A close equilibrium between MMP and pro/anti-inflammatory cytokine production is observed in ENT-RA and NAT-RA patients. This balance is apparently not influenced by the length of the disease. Highly sensitive methods such as quantitative RT-PCR and ELISA, and even studying freshly isolated MC, showed sustained cytokine secretion at the local level (synovial fluid/SFMC) and scarce translation at the peripheral level (serum/PBMC). Expression of MMP mRNA needs to be further evaluated in order to know whether their peripheral expression reflects their local activity in RA patients