Rare Complications of Two Most Common Nerve Blocks: Posterior Superior Alveolar and Inferior Alveolar Nerve Block: A Mini Review

Administration of local anesthetic agents is a safe procedure. However, various localized, distant and systemic complications have been reported. Posterior superior alveolar nerve block (PSAB) and inferior alveolar nerve block (IANB) are the two most common nerve blocks in the jaws. In this mini review, we tend to describe rare complications of these two methods. Rare complications of IANB includenecrosis of the chin skin of, neuritis of the facial nerve, trismus, ischemia and blanching of skin, anemia in the face, numbness of the ear, diplopia , taste disturbance, infra condylar abscess, burning sensation in eye, reduction in visual acuity and atrophy of the optic nerve. Some Rare complications of PSA are diplopia, amaurosis, epiphoria, paralysis, esotropia, hematoma, pupillary dilation and ptosis, paresis of the lateral pterygoid muscle and trismus. Since complications of dental anesthesia are inevitable, their prevention and management are essential. Management of complications requires comprehensive knowledge regarding the management of complications and injection techniques to prevent these complication

Dual Face of Vγ9Vδ2-T Cells in Tumor Immunology: Anti- versus Pro-Tumoral Activities

published_or_final_versio

The assembly and function of the Chaplin peptides

© 2016 Dr Mina DokouhakiThe filamentous bacterium Streptomyces coelicolor (S. coelicolor) produces small hydrophobic peptides called chaplins that play an instrumental role in the aerial growth of this microorganism. Chaplins (Chp D-H) reduce the surface tension of water and form fibrils on the surface of hyphae that facilitate the escape of hyphae into air. Temporal variation in the expression of chaplins suggests that they may have different functions in the transition from vegetative to aerial growth in S. coelicolor, likely dependent on their unique structures, however, these functions are not yet clear. The ability of chaplins to self-assemble at the interface and lower the surface tension makes them interesting candidates to use as surface active agents in food or consumer goods but their potential in this field has not been investigated. Chp E and Chp F were selected as the primary focus for this thesis. These two peptides differ in their pattern of secretion by S. coelicolor, their primary amino acid sequence and their isoelectric points (pI) (Chp E ~7, Chp F ~4). Moreover, Chp F contains two cysteine residues that are absent in Chp E. These differences make these two peptides ideal for determining whether the structure and function of the chaplin peptides differ. Also, preliminary experiments were performed on Chp H that has a similar pI and pattern of microbial secretion to Chp E. In contrast with Chp E, Chp H contains two cysteine residues in the primary amino acid sequence. This thesis has four key objectives: 1) to examine the effect of pH on the structure and self-assembly of Chp E in solution; 2) to investigate how the different structures formed by Chp E, as a function of pH, influence the interfacial properties of this peptide; 3) to determine whether Chp F and Chp E respond differently to pH, including the structure and function of the two peptides and 4) to characterise the rheological properties and thickness of the Chp E film formed at the air/water interface in comparison with β-casein and β-lactoglobulin, commonly used surface active agents in food products. The work also has a broader goal of investigating the potential of chaplin peptides as surface active agents for applications in food or consumer goods. The techniques and methods employed in this thesis include: liquid chromatography combined with tandem mass spectrometry for mass and protein identification, dynamic light scattering to measure the size of peptide in the solution, isoelectric focusing gel to determine the isoelectric point of peptides, Synchrotron radiation circular dichroism spectroscopy and circular dichroism spectroscopy to detect the secondary structure of peptide, Thioflavin T binding to assess fibril formation, sedimentation and amino acid analysis to assess conversion of peptides into fibrils, Langmuir trough experiments to develop pressure/area isotherms and measure surface activity, atomic force microscopy to measure the thickness of chaplin films assembled at the air/water interface, canal viscometry and the application of oscillating barriers studies to investigate the rheological properties of films formed at the air/water interface, transmission electron microscopy and Brewster angle microscopy for microscopic observations, Langmuir-Blodgett deposition and Langmuir-Schaefer deposition to deposit interfacial films on solid surfaces. In this thesis, molecular dynamics simulations are used to predict the three-dimensional structure of a chaplin monomer in solution as a function of pH and also to study the adsorption of chaplins at the interface. The conformation and self-assembly of Chp E in solution was found to be controlled by pH. Increasing the pH from 3.0 to 6.7, the pI of Chp E, or 10.0 promotes the self-assembly of Chp E peptides into amyloid-like fibrils that bound the dye Thioflavin T. At high pH, this assembly is rapid with no detectable lag phase and at least 93% or 97% of the Chp E peptide was converted into fibrils at the pI and pH 10.0 respectively. In contrast, molecular dynamics simulations and measurements by dynamic light scattering indicate the peptide may be present as a dimer or other loosely associated oligomer at pH 3.0, where it remains in the predominantly soluble form (> 70%). An increase in solution pH is accompanied by changes in the size and structure of Chp E; at low pH the peptide has a random coil structure with a diameter of 3.6 ± 1 nm (> 98% of the population), while at higher pH it adopts a β-sheet conformation with a diameter of 417 nm or 1110 ± 170 nm (> 99% of the population) for the pI and pH 10.0 respectively. MD simulations suggested that electrostatic repulsion between residues His6 and Lys10 in the N-terminus stabilize the Chp E peptide at low pH. The progressive reduction in electrostatic repulsion at higher pH leads to an α-helical structure at the N-terminus, which potentially acts as an intermediate on the path to fibril formation. The different structures formed by Chp E as a function of pH influence the interfacial assembly and function of this peptide as a surface active agent. Chp E monomers at pH 3.0 were found to be more effective at lowering the surface tension of water than Chp E fibrils at pH 10.0, likely due to the greater exposure of hydrophobic residues to the interface at pH 3.0. Microscopic observations showed that at pH 3.0, Chp E forms a homogenous smooth film at the air/water interface that contains ordered structures aligned in one direction. Peptides in this film have a random coil structure with no evidence of fibrils forming under this condition. In contrast, the heterogeneous film formed by Chp E at the interface at pH 10.0 is composed of fibrils oriented randomly over the film. This film is ~10 fold thicker and ~34 fold rougher compared to the film formed by Chp E at pH 3.0, when the films were transferred onto a Si surface and dried. This finding suggests that Chp E molecules could layer on top of one another at the interface at basic pH. Molecular dynamics simulations predict a higher dimerisation propensity for Chp E at pH 10.0 compared to pH 3.0. The formation of dimers, which typically occurs through hydrophobic contacts, potentially reduces the exposure of hydrophobic residues to the hydrophobic/hydrophilic interface, consistent with a lower diffusion rate to the interface simulated at pH 10.0 and lower surface activity observed experimentally for Chp E at pH 10.0 compared to at lower pH. A greater number of inter-molecular contacts were simulated between Chp E molecules at the interface at pH 10.0 compared to at pH 3.0, consistent with the compact assembly and lower area occupied by each Chp E molecule at pH 10.0, as indicated by the measured pressure/area isotherms. A model was presented describing the potential role of Chp E in the transition from vegetative to aerial growth during the life cycle of S. coelicolor. At acidic pH, during the vegetative growth of the microorganism, Chp E self-assembles at the air/water interface into a non-amyloidal membrane that displays significant surface activity assisting aerial growth. At a basic pH, Chp E contributes to the self-assembly of chaplins into fibrils at the surface of hyphae, increasing the surface hydrophobicity of aerial structures. This step coincides with the formation of continuous and abundant growth of aerial hyphae favoured at neutral or basic pH. During vegetative growth, Chp H with the pI of ~7 is secreted simultaneously with Chp E. At acidic pH, a lower surface activity was observed for this peptide compared to Chp E under the same condition. Therefore, Chp H may act as a polymerization unit in the assembly of chaplins into fibrils at the surface of aerial structures. Chp F was also found to form assemblies with different size, morphology and conformation as a function of pH, likely due to changes in the net charge and the distribution of charges over the peptide. Chp F peptides formed fibrillar assemblies rich in β-sheet structure with an average diameter of 337 ± 20 nm at pH 3.0 and 439 ± 7 nm at the pI of 4.2. The short assemblies formed by Chp F at pH 10.0 were smaller in size than those observed at lower pH, with the average diameter of 59 ± 6 nm; these preparations also contained a mixed structure of random coil and β-sheet. Fibril assembly was both quick and efficient, with yields > 99% at acidic pH and ~40% at basic pH. A greater Thioflavin T binding occurred at low pH compared to high pH, consistent with the efficient assembly observed at low pH. The presence of negative charges on the C-terminus of Chp F at high pH, could lead to an electrostatic repulsion between peptides, preventing the assembly of Chp F into fibrils. The reduction in electrostatic repulsion at acidic pH, due to a decrease in the net charge and change in the distribution of charges over the peptide, likely leads to a more energetically favorable association of Chp F peptides and the formation of fibrils. The differences between the primary amino acid sequences of Chp F and Chp E result in these two peptides responding in a complementary way to solution pH. In contrast with Chp F, the presence of positive charges on the N-terminus of Chp E at pH 3.0 inhibits the formation of fibrils by inducing repulsion between Chp E peptides. The formation of disulfide bonds was not found to be necessary for the formation of the β-sheet structure and assembly of Chp F fibrils in vitro at different solution pH. Similar CD spectra were obtained for reduced and non-reduced Chp F at different solution pH, suggesting the role of disulfide bond formation in Chp F fibril assembly is of minor importance. The pH-dependent assembly of Chp F into fibrils influenced the interfacial properties of this peptide. Surface activity was highest for samples at pH 10.0 that contained a higher proportion of unaggregated material and reduced level of β-sheet conformation, compared to the surface activity measured for Chp F fibrils formed at pH 3.0. Chp F assembly is expected to proceed through hydrophobic interactions, likely lowering the exposure of hydrophobic residues to the air/water interface, reducing the surface activity of Chp F fibrils at low pH. The surface activity of Chp F as a function of pH is similar to the surface activity observed for a mixture of chaplins (Chp D-H) but the trend observed in surface activity as a function of pH is the opposite of that observed for Chp E. This complementary behaviour could be useful in potential applications, where surface activity over a wide range of pH is desired. At acidic pH, Chp F formed a heterogeneous film at the air/water interface containing aggregated material punctuated by micro pores and long randomly arranged fibrils. In contrast, at basic pH, Chp F formed a homogenous film composed of short assemblies. The slightly reduced area occupied per Chp F molecule at pH 10.0 compared to pH 3.0 indicates a better packing of the Chp F within the short assemblies observed at pH 10.0, compared to the large fibrils observed at pH 3.0. The ordered structures within the film formed by Chp E at acidic pH resulted in higher dilatational elastic modulus compared to the fibrils within the films formed at basic pH. At both pH, Chp E also showed a higher dilatational elastic modulus compared to the surface active milk proteins, β-casein and β-lactoglobulin. In contrast, a higher elasticity was observed for the Chp E fibrillar film formed at pH 10.0 after a one hour period of oscillation (corresponding to 54 compression-expansion cycles at the constant frequency of 15 mHz), compared to the Chp E film formed at pH 3.0. This increase in elasticity could be related to structural changes induced by continuous oscillations, as the fibrils at pH 10.0 broke into shorter lengths leading to an increase in the area in contact with the interface. The continuous oscillations, however, had no significant effect on the size and morphology of the ordered structures within the film formed by Chp E at pH 3.0 and only a reduction in the alignment of these structures was observed by microscopy. A greater surface shear viscosity was observed for interfacial films formed by Chp E compared to the milk proteins, β-lactoglobulin and β-casein, with a smaller flow rate measured through the canal (0.007 mN/m.s for Chp E at pH 10.0 and 0.04 mN/m.s for Chp E at pH 3.0 vs. 0.05 mN/m.s for β-lag and 0.06 mN/m.s for β-cas). The Chp E film formed at pH 10.0 also showed 5.7 fold higher surface shear viscosity compared to the film at pH 3.0, suggesting these films may provide a higher resistance to coalescence and phase separation in dispersions at basic pH. These findings indicate that Chp E is capable of forming a film with favourable rheological properties and is a promising candidate to postpone coalescence and disproportionation, a key factor in foam coarsening. This peptide and possibly other chaplin peptides may therefore provide long term stability to foams and emulsions. In summary, the ability of chaplins E and F to reduce the surface tension and self-assemble at the air/water interface into an amphipathic film with favourable rheological properties suggests that these peptides are promising surface active agents that could be used in food or consumer goods. The insights into pH controlled assembly, structures formed at the interface and complementary behaviour of different chaplin peptides gained from this study also assists our understanding of the possible role of chaplin peptides in the differential development of S. coelicolor

Infant onset systemic lupus erythematosus presenting as nephrotic syndrome

Background: Membranous nephropathy (MGN) is one of the most common glomerular disease seen among adults. However, it is a rare histological presentation in pediatric population. In contrast to MGN in adults where primary form is known to be the leading subtype of the disease, secondary cause is more prevailing in children. Case Presentation: We describe a case of an infant presenting with nephrotic syndrome (NS) and negative serology work-up. Kidney biopsy showed the picture of severe diffuse MGN confirmed by light, immunofluorescence and electron microscopy studies. "Full-house" pattern by immunofluorescence, numerous well-demarcated sub-epithelial deposits and tubuloreticular inclusions strongly suggested type V lupus nephritis. Conclusions: NS due to MGN is rarely seen in infancy. Secondary causes such as autoimmune disease or systemic infection need to be considered for appropriate management

Advances in the application of protein-polysaccharide-polyphenol ternary complexes for creating and stabilizing Pickering emulsions

Pickering Emulsions (PEs) have gained significant attention due to their simplicity of preparation, the prospect of using a wide range of natural biopolymers to create Pickering particles and high stability. To overcome the limitations of conventional emulsions stabilized by synthetic surfactants, biopolymers such as proteins and polysaccharides are increasingly used as sustainable and eco-friendly Pickering particles for PEs. Pickering particles produced using protein-polysaccharide-polyphenol ternary complexes offer enhanced stability and functionality of PEs, overcoming issues associated with single-component or binary complexes. PEs stabilized by particles comprised of these ternary complexes find preferential applications in diverse industries, including food, cosmetics, and pharmaceuticals. This concise review presents a snapshot of recent advances in research, highlighting the nature of interactions among the components of Pickering particles, fabrication methods, and applications of these ternary complexes in Pickering emulsions

Effectiveness of an 810-nm Diode Laser in Addition to Non-surgical Periodontal Therapy in Patients With Chronic Periodontitis: A Randomized SingleBlind Clinical Trial: Effectiveness of Diode Laser in Addition to SRP in Chronic Periodontitis

Introduction: This study evaluated the effectiveness of an 810-nm diode laser as an adjunct to scaling and root planning (SRP) in improving periodontal parameters in patients with chronic periodontitis.Methods: This randomized clinical trial consisted of 36 patients (16 females and 20 males) with chronic periodontitis and pocket depths of 4-6 mm. The quadrants were randomly divided into two sides; one side of each patient was selected as the laser group (SRP + laser) and the other side served as the control group (SRP alone). An 810-nm diode laser was applied in the laser side to remove the outer gingival epithelium (1.5 W, CW) as well as the inner epithelium of the periodontal pockets (1 W, CW). The clinical parameters including bleeding on probing (BOP), probing depth (PD), plaque index (PI), and clinical attachment level (CAL) were measured at baseline and 6 and 18 weeks after therapy.Results: In both groups, there was a significant improvement in BOP, PD, PI and CAL over the course of the experiment (P<0.001). Significantly lower BOP was found in the SRP + laser group than the SRP alone group after 6 and 18 weeks of intervention (P<0.05). The difference in other parameters was not significant between the two groups, neither at 6 nor at 18 weeks after the treatment (P>0.05).Conclusion: Within the limitations of this study, the association of the diode laser with standard nonsurgical periodontal therapy (SRP) provided minimal additional benefits for patients with moderate chronic periodontitis Doi:10.34172/jlms.2021.3