Physicochemical studies of pectin/poly-L-lysine gelation

The effect of poly-L-lysine concentration and degree of polymerisation on the gelation of pectins differing in charge density and distribution was examined, through the determination of gel stiffness, swelling behaviour and the binding of poly-L-lysine to the gel network. Poly-L-lysine acts as a crosslinker of concentrated pectin solutions, with its effectiveness showing dependencies on pH and charge distribution on the pectin. Neutralisation of the anionic charge on the pectin with the polycationic peptide leads to gel opacity and eventually network collapse.     

Chromone containing sulfonamides as potent carbonic anhydrase inhibitors

A series of sulfonamide derivatives incorporating substituted 3-formylchromone moieties were investigated for the inhibition of three human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, hCA I, II, and VI. All these compounds, together with the clinically used sulfonamide acetazolamide, were investigated as inhibitors of the physiologically relevant isozymes I, II (cytosolic), and VI (secreted isoform). These sulfonamides showed effective inhibition against all these isoforms with K(I)'s in the range of 0.228 to 118 μM. Such molecules can be used as leads for discovery of novel effective CA inhibitors against other isoforms with medicinal chemistry applications.     

Alginate Films Containing Viable Lactobacillus Plantarum: Preparation and In Vitro Evaluation

The objective of the study was to develop calcium alginate films, containing Lactobacillus plantarum ATCC 8040 with preserved and stable viability and antibacterial activity. L. plantarum-loaded films containing different calcium concentrations were physically characterized for mechanical and bioadhesive properties and lactobacilli release. The viability and antibacterial activity of L. plantarum was studied before and after processing, and during 6 months of storage. A multiresistant clinical isolate, VIM-2-metalo-β-lactamase producing Pseudomonas aeruginosa, was used as an indicator strain. Interference between L. plantarum and films enhanced films elasticity, water absorption ability, release of lactobacilli, and decreased films adherence. A decrease of L. plantarum viability in alginate films (≤1 log unit) was observed after freeze drying. L. plantarum, at cell concentrations of 108 cfu/ml, was inhibitory active. The viability and antibacterial activity of the immobilized lactobacilli remained stable during 6 months of storage. The study has proved the potential of alginate films to deliver L. plantarum in high numbers to individuals.     

Controlling the near‐infrared transparency of costal cartilage by impregnation with clearing agents and magnetite nanoparticles

Penetration depth of near‐infrared laser radiation to costal cartilage is controlled by the tissue absorption and scattering, and it is the critical parameter to provide the relaxation of mechanical stress throughout the whole thickness of cartilage implant. To enhance the penetration for the laser radiation on 1.56 μm, the optical clearing solutions of glycerol and fructose of various concentrations are tested. The effective and reversible tissue clearance was achieved. However, the increasing absorption of radiation should be concerned: 5°C‐8°C increase of tissue temperature was detected. Laser parameters used for stress relaxation in cartilage should be optimized when applying optical clearing agents. To concentrate the absorption in the superficial tissue layers, magnetite nanoparticle (NP) dispersions with the mean size 95 ± 5 nm and concentration 3.9 ± 1.1 × 10¹¹ particles/mL are applied. The significant increase in the tissue heating rate was observed along with the decrease in its transparency. Using NPs the respective laser power can be decreased, allowing us to obtain the working temperature locally with reduced thermal effect on the surrounding tissue.      

Functional analysis of the matricellular protein SPARC with novel monoclonal antibodies.

SPARC (osteonectin, BM-40) is a matricellular glycoprotein that is expressed in many embryogenic and adult tissues undergoing remodeling or repair. SPARC modulates cellular interaction with the extracellular matrix (ECM), inhibits cell adhesion and proliferation, and regulates growth factor activity. To explore further the function and activity of this protein in tissue homeostasis, we have developed several monoclonal antibodies (MAbs) that recognize distinct epitopes on SPARC. The MAbs bind to SPARC with high affinity and identify SPARC by ELISA, Western blotting, immunoprecipitation, immunocytochemistry, and/or immunohistochemistry. The MAbs were also characterized in functional assays for potential alteration of SPARC activity. SPARC binds to collagen I and laminin-1 through an epitope defined by MAb 293; this epitope is not involved in the binding of SPARC to collagen III. The other MAbs did not interfere with the binding of SPARC to collagen I or III or laminin-1. Inhibition of the anti-adhesive effect of SPARC on endothelial cells by MAb 236 was also observed. Functional analysis of SPARC in the presence of these novel MAbs now confirms that the activities ascribed to this matricellular protein can be assigned to discrete subdomains.