Enhanced antibacterial activity of capped zinc oxide nanoparticles: A step towards the control of clinical bovine mastitis.

BACKGROUND AND AIM: Bovine mastitis is the costliest prevalent disease in the dairy sector due to the limitations of conventional treatments. Zinc oxide nanoparticles (ZnO-NPs) have been regarded as safe and economical antibacterial candidates against several microorganisms, but the tendency of these particles to aggregate is a major barrier to their application. This study aimed to enhance the antibacterial efficiency of ZnO-NPs against some bacterial agents, causing bovine mastitis. MATERIALS AND METHODS: A total of 24 milk samples out of 300 cases from Nubaria farm, Beheira Governorate, Egypt, were collected from cows with clinical mastitis. ZnO-NPs were fabricated by a sonochemical method using starch as a capping agent and by an auto-combustion reaction using glycine as a fuel. The two preparations of synthesized ZnO-NPs at different concentrations were assessed for their antimicrobial activities in vitro against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae isolated from milk of affected cows. RESULTS: Sonochemically synthesized capped ZnO-NPs were dispersed and non-agglomerated in comparison with aggregated uncapped ZnO-NPs prepared by an auto-combustion reaction. Capped dispersed ZnO-NPs showed higher antibacterial activity against S. aureus, E. coli, and K. pneumoniae than particles synthesized by the auto-combustion reaction at same concentrations. However, the zone of inhibition for dispersed and agglomerated ZnO-NPs was concentration-dependent. In addition, Gram-positive S. aureus exhibited higher resistance to ZnO-NPs synthesized by both methods than Gram-negative E. coli and K. pneumoniae. CONCLUSION: Dispersed, non-agglomerated ZnO-NPs fabricated using starch as a capping agent under sonochemical irradiation could potentially be regarded as highly effective and inexpensive antimicrobial agents against S. aureus, E. coli, and K. pneumoniae for the management of bovine mastitis.

Ocular anti-inflammatory activity of prednisolone acetate loaded chitosan-deoxycholate self-assembled nanoparticles.

Background and purpose: Conventional topical ophthalmic aqueous solutions and suspensions are often associated with low bioavailability and high administration frequency, pulsatile dose and poor exposure to certain ocular parts. The aim of this study was to develop an ophthalmic nanoparticles loaded gel, for delivering prednisolone acetate (PA), to increase dosing accuracy, bioavailability, and accordingly, efficiency of PA in treating inflammatory ocular diseases. Methods: A novel formulation of self-assembled nanoparticles was prepared by the complexation of chitosan (CS) and, the counter-ion, sodium deoxycholate (SD), loaded with the poorly-water-soluble PA. Particle size, zeta potential, encapsulation efficiency (EE) and drug loading content (LC) of prepared nanoparticles were assessed. Moreover, the nanoparticles were characterized using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Drug release and eye anti-inflammatory potential of the prepared novel formulation was investigated. Results: Mean particle size of the nanoparticles have dropped from 976 nm ±43 (PDI 1.285) to 480 nm ±28 (PDI 1.396) when the ratio of CS-SD was decreased. The incorporation of 0.1-0.3% of polyvinyl alcohol (PVA), in the preparation stages, resulted in smaller nanoparticles: 462 nm ±19 (PDI 0.942) and 321 nm ±22 (PDI 0.454) respectively. DSC and FTIR results demonstrated the interaction between CS and SD, however, no interactions were detected between PA and CS or SD. Drug release of PA as received, in simulated tears fluid (pH 7.4), showed a twofold increase (reaching an average of 98.6% in 24 hours) when incorporated into an optimized nanoparticle gel formulation (1:5 CS-SD). Conclusion: The anti-inflammatory effect of PA nanoparticles loaded gel on female guinea pig eyes was significantly superior to that of the micronized drug loaded gel (P < 0.05).

Influence of implant-abutment angulations and crown material on stress distribution on central incisor: a 3D FEA

Aim: To investigate the effect of implant-abutment angulation and crown material on stress distribution of central incisors. Finite element method was used to simulate the clinical situation of a maxillary rightcentral incisor restored by two different implant-abutment angulations, 15° and 25°, using two different crown materials (IPS E-Max CAD and zirconia). Methods: Two 3D finite element models were specially prepared for this research simulating the abutment angulations. Commercial engineering CAD/CAM package was used to model crown, implant abutment complex and bone(cortical and spongy) in 3D. Linear static analysis was performed by applying a 178 N oblique load.The obtained results were compared with former experimental results. Results: Implant Von Misesstress level was negligibly changed with increasing abutment angulation. The abutment with higherangulation is mechanically weaker and expected to fail at lower loading in comparison with thesteeper one. Similarly, screw used with abutment angulation of 25° will fail at lower (about one-third)load value the failure load of similar screw used with abutment angulated by 15°. Conclusions: Bone (cortical and spongy) is insensitive to crown material. Increasing abutment angulation from15° to 25°, increases stress on cortical bone by about 20% and reduces it by about 12% onspongy bone. Crown fracture resistance is dramatically reduced by increasing abutment angulation. Zirconia crown showed better performance than E-Max one.

Allogeneic stem cell transplantation in patients with ß-thalassemia: King Faisal specialist hospital and research centre experience.

From January 1998-July 2006, 62 stem cell transplantation (SCT) were performed on 60 patients with beta-thalassemia from HLA-related match donors. The overall survival (OS) and event free survival (EFS) for all patients were 94 and 77%. The outcome of allogeneic SCT in our experience is satisfactory with OS 92% and EFS 77%. Transplantation at a young age and when the disease is mild offers the best outcome. More advanced disease is associated with higher rate of rejection and severe graft versus host disease.

Equilibrium studies of organotin(IV) complexes with vitamin B(6).

The complex-formation equilibria of dimethyltin(IV), trimethyltin(IV) and tributyltin(IV) with pyridoxamine were investigated in dioxane-water mixtures and at different temperatures using a potentiometric technique. The stepwise formation constants of the complexes formed in solution were calculated using the non-linear least-square program MINIQUAD-75. The effect of dioxane as a solvent on the protonation constants of pyridoxamine and the formation constants of organotin(IV) complexes was discussed. The thermodynamic parameters DeltaH degrees and DeltaS degrees calculated from the temperature dependence of the equilibrium constants were investigated. The concentration distribution of the various complex species was evaluated as a function of pH.