The value of honey dressings in pilonidal cyst healing: a prospective randomized single-center trial.

BACKGROUND: Honey is described as a wound healing agent. Many virtues have been attributed to it, in particular, antibacterial properties. The aim of our study was to evaluate its value in healing of wounds after wide excision on pilonidal cyst healing. METHODS: A prospective randomized trial was conducted from March 2016 to February 2022 which included patients with a persistent non healed wound which required packing 6 weeks after pilonidal cyst excision. Patients were randomly allocated to simple alginate wick dressings or the same design plus honey. RESULTS: Fifty patients were included in each arm. There were 57 men and 43 women. The median age was 22 years (range 19-28 years). The mean healing time was 61 (± 44) days in the wick + honey group compared to 78 (± 55) days in the simple alginate wick group (p = 0.094). There was no significant difference between the two groups in terms of time off work and time without physical activity The VQ-Dermato quality of life score was equivalent in both groups. CONCLUSIONS: Tolerability for honey dressings is good and is equivalent to that of alginate dressings in cavity wound care. This trial did not reach a significant difference in its primary endpoint but it shows the value of honey in this indication, although its use requires further study. TRIAL REGISTRATION NUMBER: CLINICAL TRIALS: NCT02485860 and EUDRACT: 2015-A00452-47 (10/03/2015).

Staphylococcal Complement Evasion Protein Sbi Stabilises C3d Dimers by Inducing an N-Terminal Helix Swap.

Staphylococcus aureus is an opportunistic pathogen that is able to thwart an effective host immune response by producing a range of immune evasion molecules, including S. aureus binder of IgG (Sbi) which interacts directly with the central complement component C3, its fragments and associated regulators. Recently we reported the first structure of a disulfide-linked human C3d17C dimer and highlighted its potential role in modulating B-cell activation. Here we present an X-ray crystal structure of a disulfide-linked human C3d17C dimer, which undergoes a structurally stabilising N-terminal 3D domain swap when in complex with Sbi. These structural studies, in combination with circular dichroism and fluorescence spectroscopic analyses, reveal the mechanism underpinning this unique helix swap event and could explain the origins of a previously discovered N-terminally truncated C3dg dimer isolated from rat serum. Overall, our study unveils a novel staphylococcal complement evasion mechanism which enables the pathogen to harness the ability of dimeric C3d to modulate B-cell activation.

Insights Into the Structure-Function Relationships of Dimeric C3d Fragments.

Cleavage of C3 to C3a and C3b plays a central role in the generation of complement-mediated defences. Although the thioester-mediated surface deposition of C3b has been well-studied, fluid phase dimers of C3 fragments remain largely unexplored. Here we show C3 cleavage results in the spontaneous formation of C3b dimers and present the first X-ray crystal structure of a disulphide-linked human C3d dimer. Binding studies reveal these dimers are capable of crosslinking complement receptor 2 and preliminary cell-based analyses suggest they could modulate B cell activation to influence tolerogenic pathways. Altogether, insights into the physiologically-relevant functions of C3d(g) dimers gained from our findings will pave the way to enhancing our understanding surrounding the importance of complement in the fluid phase and could inform the design of novel therapies for immune system disorders in the future.

Evaluation of the efficacy and morbidity of radiofrequency thermocoagulation in the treatment of hemorrhoidal disease.

INTRODUCTION: Grade III hemorrhoidal disease may require surgical treatment. Several minimally invasive techniques can be offered to the patient, particularly ligation of the hemorrhoidal arteries/mucopexy or even stapled hemorrhoidopexy. A technique of radiofrequency thermocoagulation of hemorrhoids has recently been introduced. The aim of our study was to assess the efficacy and early morbidity of this procedure. METHODS: Data from successive patients undergoing radiofrequency thermocoagulation for grade II to IV hemorrhoidal disease between December 2017 and December 2019 were retrospectively collated. RESULTS: Seventy-four patients, with a mean age of 53 years, underwent operation during the study period. The major indication was grade III hemorrhoidal disease in 95% of patients. More than 80% of patients underwent operation as an outpatient. Eighteen (24.3%) patients developed a postoperative complication within 30 days, of whom two (2.7%) required revisional surgery for rectal bleeding and severe anal pain, respectively. Seven (9.5%) patients were re-admitted to hospital and 18 (24.3%) had an unscheduled early return visit within 30 postoperative days. At three months following surgery, the anatomical and functional result was satisfactory in more than 93% of patients. CONCLUSION: Radiofrequency hemorrhoidal thermocoagulation is an effective technique in the treatment of grade III hemorrhoidal disease. Despite a non-negligible rate of minor postoperative complications requiring an early consultation or re-hospitalisation, severe complications occurred in less than 3% of operated patients.

Monoclonal antibody stability can be usefully monitored using the excitation-energy-dependent fluorescence edge-shift.

Among the major challenges in the development of biopharmaceuticals are structural heterogeneity and aggregation. The development of a successful therapeutic monoclonal antibody (mAb) requires both a highly active and also stable molecule. Whilst a range of experimental (biophysical) approaches exist to track changes in stability of proteins, routine prediction of stability remains challenging. The fluorescence red edge excitation shift (REES) phenomenon is sensitive to a range of changes in protein structure. Based on recent work, we have found that quantifying the REES effect is extremely sensitive to changes in protein conformational state and dynamics. Given the extreme sensitivity, potentially this tool could provide a 'fingerprint' of the structure and stability of a protein. Such a tool would be useful in the discovery and development of biopharamceuticals and so we have explored our hypothesis with a panel of therapeutic mAbs. We demonstrate that the quantified REES data show remarkable sensitivity, being able to discern between structurally identical antibodies and showing sensitivity to unfolding and aggregation. The approach works across a broad concentration range (µg-mg/ml) and is highly consistent. We show that the approach can be applied alongside traditional characterisation testing within the context of a forced degradation study (FDS). Most importantly, we demonstrate the approach is able to predict the stability of mAbs both in the short (hours), medium (days) and long-term (months). The quantified REES data will find immediate use in the biopharmaceutical industry in quality assurance, formulation and development. The approach benefits from low technical complexity, is rapid and uses instrumentation which exists in most biochemistry laboratories without modification.

Analysis of Protein Glycation Using Phenylboronate Acrylamide Gel Electrophoresis.

Carbohydrate modification of proteins adds complexity and diversity to the proteome. However, undesired carbohydrate modifications also occur in the form of glycation, which have been implicated in diseases such as diabetes, Alzheimer's disease, autoimmune diseases, and cancer. The analysis of glycated proteins is challenging due to their complexity and variability. Numerous analytical techniques have been developed that require expensive specialized equipment and complex data analysis. In this chapter, we describe two easy-to-use electrophoresis-based methods that will enable researchers to detect, identify, and analyze these posttranslational modifications. This new cost-effective methodology will aid the detection of unwanted glycation products in processed foods and may lead to new diagnostics and therapeutics for age-related chronic diseases.

The synthesis and kinetic evaluation of aryl α-aminophosphonates as novel inhibitors of T. cruzi trans-sialidase.

The trans-sialidase protein expressed by Trypanosoma cruzi is an important enzyme in the life cycle of this human pathogenic parasite and is considered a promising target for the development of new drug treatments against Chagas' disease. Here we describe α-amino phosphonates as a novel class of inhibitor of T. cruzi trans-sialidase. Molecular modelling studies were initially used to predict the active-site binding affinities for a series of amino phosphonates, which were subsequently synthesised and their IC50s determined in vitro. The measured inhibitory activities show some correlation with the predictions from molecular modelling, with 1-napthyl derivatives found to be the most potent inhibitors having IC50s in the low micromolar range. Interestingly, kinetic analysis of the mode of inhibition demonstrated that the α-aminophosphonates tested here operate in a non-competitive manner.

Is histological analysis of pilonidal sinus useful? Retrospective analysis of 731 resections.

The pilonidal sinus (SP) is a common pathology. The treatment is a surgical excision. Many surgeons continue to systematically send this SP in histological analysis. The objective of our retrospective study was to evaluate the interest of this systematic histological analysis. The retrospective analysis of patients undergoing surgery was performed between 1 January 2006 and 31 December 2014. The primary observation was the presence of a malignant disease on the surgical specimen. Secondary observations were the wound healing time and the rate of recurrence. Seven hundred and thirty-one patients were analyzed. There was no malignant lesion. For 323 patients, the histological analysis did not describe the resection margins. Two hundred and eighty five patients had complete resect on and 38 were incomplete. Twenty-four patients had recurrence (7%). There was no significant difference between those who had complete and incomplete resection. The healing time was 61 days. Our study raises the question about the value of systematic histological analysis of the PS specimen.

Utilization of Staphylococcal Immune Evasion Protein Sbi as a Novel Vaccine Adjuvant.

Co-ligation of the B cell antigen receptor with complement receptor 2 on B-cells via a C3d-opsonised antigen complex significantly lowers the threshold required for B cell activation. Consequently, fusions of antigens with C3d polymers have shown great potential in vaccine design. However, these linear arrays of C3d multimers do not mimic the natural opsonisation of antigens with C3d. Here we investigate the potential of using the unique complement activating characteristics of Staphylococcal immune-evasion protein Sbi to develop a pro-vaccine approach that spontaneously coats antigens with C3 degradation products in a natural way. We show that Sbi rapidly triggers the alternative complement pathway through recruitment of complement regulators, forming tripartite complexes that act as competitive antagonists of factor H, resulting in enhanced complement consumption. These functional results are corroborated by the structure of the complement activating Sbi-III-IV:C3d:FHR-1 complex. Finally, we demonstrate that Sbi, fused with Mycobacterium tuberculosis antigen Ag85b, causes efficient opsonisation with C3 fragments, thereby enhancing the immune response significantly beyond that of Ag85b alone, providing proof of concept for our pro-vaccine approach.

The red edge excitation shift phenomenon can be used to unmask protein structural ensembles: implications for NEMO-ubiquitin interactions.

To understand complex molecular interactions, it is necessary to account for molecular flexibility and the available equilibrium of conformational states. Only a small number of experimental approaches can access such information. Potentially steady-state red edge excitation shift (REES) spectroscopy can act as a qualitative metric of changes to the protein free energy landscape (FEL) and the equilibrium of conformational states. First, we validate this hypothesis using a single Trp-containing protein, NF-κB essential modulator (NEMO). We provide detailed evidence from chemical denaturation studies, macromolecular crowding studies, and the first report of the pressure dependence of the REES effect. Combination of these data demonstrate that the REES effect can report on the 'ruggedness' of the FEL and we present a phenomenological model, based on realistic physical interpretations, for fitting steady-state REES data to allow quantification of this aspect of the REES effect. We test the conceptual framework we have developed by correlating findings from NEMO ligand-binding studies with the REES data in a range of NEMO-ligand binary complexes. Our findings shed light on the nature of the interaction between NEMO and poly-ubiquitin, suggesting that NEMO is differentially regulated by poly-ubiquitin chain length and that this regulation occurs via a modulation of the available equilibrium of conformational states, rather than gross structural change. This study therefore demonstrates the potential of REES as a powerful tool for tackling contemporary issues in structural biology and biophysics and elucidates novel information on the structure-function relationship of NEMO and key interaction partners.

Why are the 2-oxoacid dehydrogenase complexes so large? Generation of an active trimeric complex.

The four-component polypeptides of the 2-oxoacid dehydrogenase complex from the thermophilic archaeon Thermoplasma acidophilum assemble to give an active multienzyme complex possessing activity with the branched-chain 2-oxoacids derived from leucine, isoleucine and valine, and with pyruvate. The dihydrolipoyl acyl-transferase (E2) core of the complex is composed of identical trimer-forming units that assemble into a novel 42-mer structure comprising octahedral and icosahedral geometric aspects. From our previously determined structure of this catalytic core, the inter-trimer interactions involve a tyrosine residue near the C-terminus secured in a hydrophobic pocket of an adjacent trimer like a ball-and-socket joint. In the present study, we have deleted the five C-terminal amino acids of the E2 polypeptide (IIYEI) and shown by equilibrium centrifugation that it now only assembles into a trimeric enzyme. This was confirmed by SAXS analysis, although this technique showed the presence of approximately 20% hexamers. The crystal structure of the trimeric truncated E2 core has been determined and shown to be virtually identical with the ones observed in the 42-mer, demonstrating that removal of the C-terminal anchor does not significantly affect the individual monomer or trimer structures. The truncated E2 is still able to bind both 2-oxoacid decarboxylase (E1) and dihydrolipoamide dehydrogenase (E3) components to give an active complex with catalytic activity similar to the native multienzyme complex. This is the first report of an active mini-complex for this enzyme, and raises the question of why all 2-oxoacid dehydrogenase complexes assemble into such large structures.

Laparoscopic incisional hernia repair: long term results.

OBJECTIVE: The aim of this prospective monocenter study was to evaluate the long-term results of laparoscopic treatment of incisional hernias using intra-peritoneal prosthetic mesh. PATIENTS AND METHODS: Seventy-seven patients underwent laparoscopic treatment of incisional hernia between January 2002 and January 2008. All patients were followed for at least five years after surgery. The parameters assessed were hernia recurrences and post-operative pain. In case of doubt as to the diagnosis of recurrence or pain, a CT examination was performed. RESULTS: Nine patients were excluded: four patients refused to participate in the study and five died of unrelated disease during follow-up. Sixty-eight patients (89.7%) were followed for a mean of 92.3 (± 19.8)months. Mean age of patients was 58 (± 11.3)years. There were no deaths and no conversions. The mean operative time was 104 (± 48)minutes. The morbidity rate was 13.2%. Major complications included one case each of mesh infection, post-operative peritonitis (bowel injury), and surgical site pain requiring revisional surgery. Five patients developed seroma. The mean duration of hospitalization was 4.5 (± 2.3) days. The long-term recurrence rate was 8.8%. The average interval to onset of recurrence was 45.8 (± 31.1)months. Trocar site hernias were observed in three patients. Four patients had post-operative pain requiring long-term medical treatment. CONCLUSION: Laparoscopic incisional hernia repair using intra-peritoneal prosthetic mesh is a safe technique with satisfactory long-term outcome. One major complication occurred: bowel injury. Suture closure of 10mm trocar sites should be routine.

Analysis of protein glycation using fluorescent phenylboronate gel electrophoresis.

Glycated proteins are important biomarkers for age-related disorders, however their analysis is challenging because of the complexity of the protein-carbohydrate adducts. Here we report a method that enables the detection and identification of individual glycated proteins in complex samples using fluorescent boronic acids in gel electrophoresis. Using this method we identified glycated proteins in human serum, insect hemolymph and mouse brain homogenates, confirming this technique as a powerful proteomics tool that can be used for the identification of potential disease biomarkers.

Robotic-assisted total mesorectal excision with the aid of a single-port device.

UNLABELLED: INTRODUCTION AND INDICATIONS: Robotic surgery has numerous advantages in rectal cancer surgery. Studies have reported the advantages associated with single-port approaches, such as eliminating the need for additional incisions, as well as the difficulties inherent in this technique. The authors present a hybrid technique that they performed using a robotic total mesorectal excision with the aid of a single port-device. Materials and methods. The authors performed the technique on 2 patients using a single-port device through an umbilical incision and 3 accessory ports for the robotic arms. There was no need to place ports for the assistant's equipment or for an assistant incision. RESULTS AND COMPLICATIONS: The operation time was 177.5 minutes, and there were no intraoperative or postoperative complications. Both patients were discharged 7 days after the operation. CONCLUSIONS: This technical variation is an additional step forward for oncological surgery with minimal damage to the abdominal wall.

Exploiting the reversible covalent bonding of boronic acids: recognition, sensing, and assembly.

Boronic acids can interact with Lewis bases to generate boronate anions, and they can also bind with diol units to form cyclic boronate esters. Boronic acid based receptor designs originated when Lorand and Edwards used the pH drop observed upon the addition of saccharides to boronic acids to determine their association constants. The inherent acidity of the boronic acid is enhanced when 1,2-, 1,3-, or 1,4-diols react with boronic acids to form cyclic boronic esters (5, 6, or 7 membered rings) in aqueous media, and these interactions form the cornerstone of diol-based receptors used in the construction of sensors and separation systems. In addition, the recognition of saccharides through boronic acid complex (or boronic ester) formation often relies on an interaction between a Lewis acidic boronic acid and a Lewis base (proximal tertiary amine or anion). These properties of boronic acids have led to them being exploited in sensing and separation systems for anions (Lewis bases) and saccharides (diols). The fast and stable bond formation between boronic acids and diols to form boronate esters can serve as the basis for forming reversible molecular assemblies. In spite of the stability of the boronate esters' covalent B-O bonds, their formation is reversible under certain conditions or under the action of certain external stimuli. The reversibility of boronate ester formation and Lewis acid-base interactions has also resulted in the development and use of boronic acids within multicomponent systems. The dynamic covalent functionality of boronic acids with structure-directing potential has led researchers to develop a variety of self-organizing systems including macrocycles, cages, capsules, and polymers. This Account gives an overview of research published about boronic acids over the last 5 years. We hope that this Account will inspire others to continue the work on boronic acids and reversible covalent chemistry.

From genotype to phenotype: can systems biology be used to predict Staphylococcus aureus virulence?

With the advent of high-throughput whole-genome sequencing, it is now possible to sequence a bacterial genome in a matter of hours. However, although the presence or absence of a particular gene can be determined, we do not yet have the tools to extract information about the true virulence potential of an organism from sequence data alone. Here, we focus on the important human pathogen Staphylococcus aureus and present a framework for the construction of a broad systems biology-based tool that could be used to predict virulence phenotypes from S. aureus genomic sequences using existing technology.

The development of boronic acids as sensors and separation tools.

Synthetic receptors for diols that incorporate boronic acid motifs have been developed as new sensors and separation tools. Utilizing the reversible interactions of diols with boronic acids to form boronic esters under new binding regimes has provided new hydrogel constructs that have found use as dye-displacement sensors and electrophoretic separation tools; similarly, molecular boronic-acid-containing chemosensors were constructed that offer applications in the sensing of diols. This review provides a somewhat-personal perspective of developments in boronic-acid-mediated sensing and separation, placed in the context of the seminal works of others in the area, as well as offering a concise summary of the contributions of the co-authors in the area.

Analysis of protein glycation using phenylboronate acrylamide gel electrophoresis.

Carbohydrate modification of proteins adds complexity and diversity to the proteome. However, undesired carbohydrate modifications also occur in the form of glycation, resulting in diseases such as diabetes, Alzheimer's disease, autoimmune diseases, and cancer. The analysis of glycated proteins is challenging due to their complexity and variability. Numerous analytical techniques have been developed that require expensive specialised equipment and complex data analysis. In this chapter, we describe a simple electrophoresis-based method that enables users to detect, identify, and analyze these post-translational modifications. This new cost-effective methodology will aid the detection of unwanted glycation products in processed foods and may lead to new diagnostics and therapeutics for age-related chronic diseases and glycosylation disorders.

Comparison of a basic and an advanced pharmacotherapy-related clinical decision support system in a hospital care setting in the Netherlands.

UNLABELLED: OBJECTIVE To compare the clinical relevance of medication alerts in a basic and in an advanced clinical decision support system (CDSS). DESIGN: A prospective observational study. MATERIALS AND METHODS: We collected 4023 medication orders in a hospital for independent evaluation in two pharmacotherapy-related decision support systems. Only the more advanced system considered patient characteristics and laboratory test results in its algorithms. Two pharmacists assessed the clinical relevance of the medication alerts produced. The alert was considered relevant if the pharmacist would undertake action (eg, contact the physician or the nurse). The primary analysis concerned the positive predictive value (PPV) for clinically relevant medication alerts in both systems. RESULTS: The PPV was significantly higher in the advanced system (5.8% vs 17.0%; p<0.05). Significant differences were found in the alert categories: drug-(drug) interaction (9.9% vs 14.8%; p<0.05), drug-age interaction (2.9% vs 73.3%; p<0.05), and dosing guidance (5.6% vs 16.9%; p<0.05). Including laboratory values and other patient characteristics resulted in a significantly higher PPV for the advanced CDSS compared to the basic medication alerts (12.2% vs 23.3%; p<0.05). CONCLUSION: The advanced CDSS produced a higher proportion of clinically relevant medication alerts, but the number of irrelevant alerts remained high. To improve the PPV of the advanced CDSS, the algorithms should be optimized by identifying additional risk modifiers and more data should be made electronically available to improve the performance of the algorithms. Our study illustrates and corroborates the need for cyclic testing of technical improvements in information technology in circumstances representative of daily clinical practice.

The catalytic core of an archaeal 2-oxoacid dehydrogenase multienzyme complex is a 42-mer protein assembly.

The dihydrolipoyl acyl-transferase (E2) enzyme forms the structural and catalytic core of the tripartite 2-oxoacid dehydrogenase multienzyme complexes of the central metabolic pathways. Although this family of multienzyme complexes shares a common architecture, their E2 cores form homo-trimers that, depending on the source, further associate into either octahedral (24-mer) or icosahedral (60-mer) assemblies, as predicted by the principles of quasi-equivalence. In the crystal structure of the E2 core from Thermoplasma acidophilum, a thermophilic archaeon, the homo-trimers assemble into a unique 42-mer oblate spheroid. Analytical equilibrium centrifugation and small-angle X-ray scattering analyses confirm that this catalytically active 1.08 MDa assembly exists as a single species in solution, forming a hollow spheroid with a maximum diameter of 220 Å. In this paper we show that a monodisperse macromolecular assembly, built from identical subunits in non-identical environments, forms an irregular protein shell via non-equivalent interactions. This unusually irregular protein shell, combining cubic and dodecahedral geometrical elements, expands on the concept of quasi-equivalence as a basis for understanding macromolecular assemblies by showing that cubic point group symmetry is not a physical requirement in multienzyme assembly. These results extend our basic knowledge of protein assembly and greatly expand the number of possibilities to manipulate self-assembling biological complexes to be utilized in innovative nanotechnology applications.