Preparing a Bioactive (Chitosan/Sodium Hyaluronate)/SrHA Coating on Mg–Zn–Ca Alloy for Orthopedic Implant Applications

The uncontrollable rapid degradation rate of the Mg alloy substrate limited its clinical application, and implant-associated infections have been reported to be the main reason for the secondary surgery of orthopedic implantation. The aim of this study was to produce a multifunctional coating on magnesium-based alloys that have improved corrosion resistance, bioactivity, and antibacterial properties through the preparation of polyelectrolytic multilayers (PEMs) consisting of chitosan (CS) and sodium hyaluronate (HA) on silane-modified strontium-substituted hydroxyapatite (hereafter referred to as Bil (SH + CS)/SrHA). The multifunctional coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results showed the polyelectrolyte complex SH/CS layer to be uniformly and tightly attached on to the surface of silane-treated SrHA. At the same time, a potentiodynamic polarization test and hydrogen evolution test showed the Bil (SH + CS)/SrHA coatings to exhibit superior corrosion resistance than bulk Mg-based alloys. The results of the cell–surface interactions revealed Bil (SH + CS)/SrHA coatings to be in favor of cell initial adhesion and more beneficial to the proliferation and growth of cells with the processing of co-culture. In addition, antibacterial tests demonstrated the strong bactericidal effect of Bil (SH + CS)/SrHA coatings against both Escherichia coli (E. coli) and Staphylococcus (S. aureus), suggesting that Bil (SH + CS)/SrHA coatings can successfully achieve multifunctionality with enhanced corrosion resistance, biocompatibility, and antibacterial properties.

The effect of phenylephrine hydrochloride 2.5 % and sodium hyaluronate solution on visual functions and accommodation in children with myopia and its local tolerability

Purpose: to evaluate visual functions, accommodation, and local tolerance in children instilled with Phenylephrine hydrochloride 2.5 % and sodium hyaluronate solution (Stelphrin Supra). Material and methods. 30 children (60 eyes) aged 8 to 12 (ave. 10.04 ± 0.24) with low (28 eyes) and moderate (32 eyes) myopia (ave. -2.96 ± 0.17 D) were tested. Refractometry, subjective and objective accommodation, optical biometry, anterior corneal surface examination, Norn test, and polling were performed prior to one-time instillation, 30 minutes after it, and after 1 month of daily bedtime instillations of Stelphrin Supra. Results. We noted a significant decrease in the tone of accommodation in the open field by 90 % from the initial value, an approximation of the nearest point of clear vision by 27 %, an increase in the volume of absolute accommodation by 57 % and the objective amplitude of accommodation by 20 %, which indicates an increase in the accommodation ability. The pupil width increased 30 minutes after a single instillation of Stelphrin Supra, which coincided with an increase in the relative accommodation reserve by 25 % from the initial one. After a month, the pupil width significantly decreased, and the positive relative accommodation reserve decreased to a level only 12 % higher than the original one. Tear film break time significantly increased by 0.89 sec, singular spot stainings disappeared in 2 out of 6 patients, lacrimation — in 6 out of 10, pain — in 1 out of 2, blurring in 4 out of 6, feeling of “sand” — in 7 out of 9 patients who had these symptoms before instillations. Conclusion. Regular instillations of Stelphrin Supra reduce the habitual tone of accommodation, increase the accommodation ability, and improve the condition of the eye surface.

The Interactions and Release Kinetics of Sodium Hyaluronate Implemented in Nonionic and Anionic Polymeric Hydrogels, Studied by Immunoenzymatic ELISA Test

Hyaluronan is a natural polymer that was introduced to wound therapy. Formulations based on synthetic polymers such as methylcellulose (MC) and polyacrylic acid (PA) containing hyaluronan (HA) were proposed for the development of prospective wound-healing preparations. The formulations of different carrier concentrations containing a fixed amount of HA were prepared, and their viscosity was measured. The HA release was evaluated by employing the apparatus paddle over a disc. The hydrogels were introduced to the donor chamber, and HA was released to the pH = 7.4 buffer. The amount of HA released was obtained using the ELISA test. The release was analyzed on the basis of different kinetic models: zero-, first-, and second-order kinetics, as well as Higuchi and Korsmeyer–Peppas equations. The release rate constants and the half release time were calculated from these equations. According to the value of the coefficient of the determination, the best model describing the observed process was selected. The comparison between the dissolution profiles was carried out by calculating the difference factor f1 and the similarity factor f2. The interaction between the hydrogel components was investigated by Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) measurements. The study revealed that the zero-order equation best described the release of HA from the formulations studied. The FTIR research and the DSC study showed the intermolecular interaction between HA chains in MC-based compositions, as well as between HA and the synthetic polymer in the PA-based formulations. The study revealed that the formulation with a higher concentration of synthetic polymer may prolong the release of HA. The obtained results indicated that the proposed hydrogels have potential for wound healing and may accelerate skin regeneration.

Surgical treatment of retinal detachment with inferior break using combined gas-air tamponade with viscoelastic

Surgical treatment of rhegmatogenous retinal detachment with an inferior break remains a challenge for ophthalmic surgeons. When using silicone tamponade, complications can develop, such as increased intraocular pressure and emulsification of silicone. In recent years, tamponade of the vitreous cavity with a gas-air mixture has been actively used, however, not all patients can observe the forced position face down, and the tamponade itself is not long-term. Purpose. The authors proposed a method for the treatment of rhegmatogenous retinal detachment with an inferior break using a combined tamponade with a gas-air mixture and viscoelastic based on sodium hyaluronate. Material and methods. A clinical observation of a patient successfully operated on with the use of the specified combined tamponade is presented. A detailed description of a new surgical technique is presented, which allows achieving a higher anatomical and functional results. Conclusion. To confirm the effectiveness and safety of the proposed method, further studies on a group of patients are needed. Key words: rhegmatogenous retinal detachment, inferior break, gas-air tamponade, tamponade with viscoelastic, sodium hyalur onate

GlicoPro, Novel Standardized and Sterile Snail Mucus Extract for Multi-Modulative Ocular Formulations. New Perspective in Dry Eye Disease Management

This study aimed to evaluate the mucoadhesive and regenerative properties of a novel lubricating multimolecular ophthalmic solution (GlicoPro®) extracted from snail mucus and its potential anti-inflammatory and analgesic role in the management of dry eye disease (DED). GlicoPro bio-adhesive efficacy was assessed using a lectin-based assay, and its regenerative properties were studied in a human corneal epithelial cell line. In vitro DED was induced in human corneal tissues; the histology and mRNA expression of selected genes of inflammatory and corneal damage biomarkers were analyzed in DED tissues treated with GlicoPro. A higher percentage of bio-adhesivity was observed in corneal cells treated with GlicoPro than with sodium hyaluronate-based compounds. In the scratch test GlicoPro improved in vitro corneal wound healing. Histo-morphological analysis revealed restoration of cellular organization of the corneal epithelium, microvilli, and mucin network in DED corneal tissues treated with GlicoPro. A significant reduction in inflammatory and ocular damage biomarkers was observed. High-performance liquid chromatography-mass spectrometry analysis identified an endogenous opioid, opiorphin, in the peptide fraction of GlicoPro. In conclusion, GlicoPro induced regeneration and bio-adhesivity in corneal cells; moreover, considering its anti-inflammatory and analgesic properties, this novel ophthalmic lubricating solution may be an innovative approach for the management of DED.