Melt-spun bioactive sutures containing nanohybrids for local delivery of anti-inflammatory drugs.

In this work, a novel concept is introduced in drug-eluting fibres to ensure a good control of drug delivery features and wide applicability to different bioactive compounds. Composite bioactive sutures based on fibre grade poly(ε-caprolactone) (PCL) and loaded with the anti-inflammatory drug Diclofenac (Dic) or a Dic nanohybrid where the drug is intercalated in a synthetic hydrotalcite (Mg/Al hydroxycarbonate) (HT-Dic) were developed. Fibres were prepared by melt-spinning at different PCL/HT-Dic/Dic ratios and analysed in terms of morphology, mechanical properties and drug release features. Results emphasized that tensile properties of fibres are clearly affected by Dic or HT-Dic addition, while the presence of knots has limited influence on the mechanical behaviour of the sutures. Release of Dic strongly depends on how Dic is loaded in the fibre (as free or nanohybrid) whereas the combination of free Dic and HT-Dic can allow a further tuning of release profile. In vivo experiments show a reduction of inflammatory responses associated with Dic-loaded fibers. Thus, a proof of principle is provided for a novel class of bioactive sutures integrating advanced controlled-release technologies

NMR Studies on Structure and Dynamics of the Monomeric Derivative of BS-RNase: New Insights for 3D Domain Swapping

Three-dimensional domain swapping is a common phenomenon in pancreatic-like ribonucleases. In the aggregated state, these proteins acquire new biological functions, including selective cytotoxicity against tumour cells. RNase A is able to dislocate both N- and C-termini, but usually this process requires denaturing conditions. In contrast, bovine seminal ribonuclease (BS-RNase), which is a homo-dimeric protein sharing 80% of sequence identity with RNase A, occurs natively as a mixture of swapped and unswapped isoforms. The presence of two disulfides bridging the subunits, indeed, ensures a dimeric structure also to the unswapped molecule. In vitro, the two BS-RNase isoforms interconvert under physiological conditions. Since the tendency to swap is often related to the instability of the monomeric proteins, in these paper we have analysed in detail the stability in solution of the monomeric derivative of BS-RNase (mBS) by a combination of NMR studies and Molecular Dynamics Simulations. The refinement of NMR structure and relaxation data indicate a close similarity with RNase A, without any evidence of aggregation or partial opening. The high compactness of mBS structure is confirmed also by H/D exchange, urea denaturation, and TEMPOL mapping of the protein surface. The present extensive structural and dynamic investigation of (monomeric) mBS did not show any experimental evidence that could explain the known differences in swapping between BS-RNase and RNase A. Hence, we conclude that the swapping in BS-RNase must be influenced by the distinct features of the dimers, suggesting a prominent role for the interchain disulfide bridges

Ciprofloxacin-loaded calcium alginate wafers prepared by freeze-drying technique for potential healing of chronic diabetic foot ulcers

Calcium alginate (CA) wafer dressings were prepared by lyophilization of hydrogels to deliver ciprofloxacin (CIP) directly to the wound site of infected diabetic foot ulcers (DFUs). The dressings were physically characterized by scanning electron microscopy (SEM), texture analysis (for mechanical and in vitro adhesion properties), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Further, functional properties essential for wound healing, i.e., porosity, in vitro swelling index, water absorption (Aw), equilibrium water content (EWC), water vapor transmission rate (WVTR), evaporative water loss (EWL), moisture content, in vitro drug release and kinetics, antimicrobial activity, and cell viability (MTT assay) were investigated. The wafers were soft, of uniform texture and thickness, and pliable in nature. Wafers showed ideal wound dressing characteristics in terms of fluid handling properties due to high porosity (SEM). XRD confirmed crystalline nature of the dressings and FTIR showed hydrogen bond formation between CA and CIP. The dressings showed initial fast release followed by sustained drug release which can inhibit and prevent re-infection caused by both Gram-positive and Gram-negative bacteria. The dressings also showed biocompatibility (> 85% cell viability over 72 h) with human adult keratinocytes. Therefore, it will be a potential medicated dressing for patients with DFUs infected with drug-resistant bacteria

A NAD(P)H oxidase isolated from the archaeon Sulfolobus solfataricus is not homologous with another NADH oxidase present in the same microorganism

A NAD(P)H oxidase has been isolated from the ar- chaeon Sulfolobus solfataricus. The enzyme is a ho- modimer with Mr 38,000 per subunit (SsNOX38) contain- ing 1 FAD molecule/subunit. It oxidizes NADH and, less efficiently, NADPH with the formation of hydrogen per- oxide. The enzyme was resistant against chemical and physical denaturating agents. The temperature for its half-denaturation was 93 and 75 °C in the absence or presence, respectively, of 8 M urea. The enzyme did not show any reductase activity. The SsNOX38 encoding gene was cloned and sequenced. It accounted for a prod- uct of 36.5 kDa. The translated amino acid sequence was made of 332 residues containing two putative -fold regions, typical of NAD- and FAD-binding proteins. The primary structure of SsNOX38 did not show any homol- ogy with the N-terminal amino acid sequence of a NADH oxidase previously isolated from S. solfataricus (Ss- NOX35) (Masullo, M., Raimo, G., Dello Russo, A., Boc- chini, V. and Bannister, J. V. (1996) Biotechnol. Appl. Biochem. 23, 47–54). Conversely, it showed 40% sequence identity with a putative thioredoxin reductase from Ba- cillus subtilis, but it did not contain cysteines, which are essential for the activity of the reductase

G13A substitution affects the biochemical and physical properties of the elongation factor 1a. A reduced intrinsic GTPase is partially restored by kirromycin

The G13A substitution in the G13XXXXGK[T,S] consensus sequence of the elongation factor 1R from the archaeon Sulfolobus solfataricus (SsEF-1R) was introduced in order to study the reasons for selective differences found in the homologous consensus element AXXXXGK[T,S] of the other elongation factor EF-2 or EF-G. In a previous work, it was shown that the main effect of the A26G mutation was the activation of the intrinsic GTPase of SsEF-2 [De Vendittis, E., Adinolfi, B. S., Amatruda, M. R., Raimo, G., Masullo, M., and Bocchini, V. (1994) Eur. J. Biochem. 262, 600-605]. In this work, we found that, compared to the wild-type factor (SsEF-1R wt), G13ASsEF-1R shows (i) a reduced rate of [3H]Phe polymerization that was probably due to its reduced ability to form a ternary complex with heterologous aa-tRNA and (ii) a reduced intrinsic GTPase activity that was stimulated by high concentrations of NaCl (GTPaseNa) [Masullo, M., De Vendittis, E., and Bocchini, V. (1994) J. Biol. Chem. 269, 20376- 20379]. In addition, G13ASsEF-1R showed an increased affinity for GDP and GTP. Surprisingly, the decreased intrinsic GTPaseNa of G13ASsEF-1R can be partially restored by kirromycin, an effect not found for SsEF-1R wt. The temperature inducing a 50% denaturation of G13ASsEF-1R was somewhat lower (-5 °C) than that of SsEF-1R wt, and the decrease in its thermophilicity was slightly more accentuated (-10 °C). These results indicate that the nature of the residue in position 13 is important for the functional and physical properties of SsEF-1R

Web-based Conferencing: What Radiology Educators Need to Know

© 2019 The Association of University Radiologists Advances in technology have resulted in the significant growth of web-based conferencing and teaching. While these remote sessions have many advantages, they may result in challenges and frustration for both host and attendees when there are technological issues, poor or distracting audio, or ineffective presentation styles. Knowing a few basic concepts behind web conferencing and preparing in advance can markedly improve the experience and facilitate effective distance learning and collaboration

3D-printed scaffold composites for the stimuli-induced local delivery of bioactive adjuncts

Polysaccharide scaffolds have been successfully employed to reconstruct environments that sustain skin tissue regeneration after injuries. Three-dimensional (3D) advanced additive manufacturing technologies allow creating scaffolds with controlled and reproducible macro- and micro-structure that improve the quality of the restored tissue to favor spontaneous repair. However, when persistent inflammation occurs, the physiological tissue healing capacity is reduced, like in the presence of pathologies like diabetes, vascular diseases, chronic infection, and others. In these circumstances, the bioavailability of therapeutic adjuncts like the growth factors in addition to the standard treatments represents undoubtedly a promising strategy to accelerate the healing of skin lesions. Precisely designed polysaccharide scaffolds obtained by 3D printing represent a robust platform that can be further implemented with the controlled delivery of bioactive adjuncts. Human elastin-like polypeptides (HELPs) are stimuli-responsive biopolymers. Their structure allows the integration of domains endowed with biological functionality, making them attractive compounds to prepare composites with smart properties. In the present study, 3D-printed alginate and chitosan scaffolds were combined with the HELP components. The HELP biopolymer was fused to the epidermal growth factor (EGF) as the bioactive domain. Different constructs were prepared and the stimuli-responsive behavior as well as the biological activity were evaluated, suggesting that these smart bioactive composites are suitable to realize multifunctional dressings that sustain the local release of therapeutic adjuncts