Guidelines on the classification of foot ulcers in people with diabetes (IWGDF 2023 update)

BACKGROUND

This publication represents a scheduled update of the 2019 guidelines of the International Working Group of the Diabetic Foot (IWGDF) addressing the use of systems to classify foot ulcers in people with diabetes in routine clinical practice. The guidelines are based on a systematic review of the available literature that identified 28 classifications addressed in 149 articles and, subsequently, expert opinion using the GRADE methodology.

METHODS

First, we have developed a list of classification systems considered as being potentially adequate for use in a clinical setting, through the summary of judgements for diagnostic tests, focussing on the usability, accuracy and reliability of each system to predict ulcer-related complications as well as use of resources. Second, we have determined, following group debate and consensus, which of them should be used in specific clinical scenarios. Following this process, in a person with diabetes and a foot ulcer we recommend: (a) for communication among healthcare professionals: to use the SINBAD (Site, Ischaemia, Bacterial infection, Area and Depth) system (first option) or consider using WIfI (Wound, Ischaemia, foot Infection) system (alternative option, when the required equipment and level of expertise is available and it is considered feasible) and in each case the individual variables that compose the systems should be described rather than a total score; (b) for predicting the outcome of an ulcer in a specific individual: no existing system could be recommended; (c) for characterising a person with an infected ulcer: the use of the IDSA/IWGDF classification (first option) or consider using the WIfI system (alternative option, when the required equipment and level of expertise is available and it is considered as feasible); (d) for characterising a person with peripheral artery disease: consider using the WIfI system as a means to stratify healing likelihood and amputation risk; (e) for the audit of outcome(s) of populations: the use of the SINBAD score.

CONCLUSIONS

For all recommendations made using GRADE, the certainty of evidence was judged, at best, as being low. Nevertheless, based on the rational application of current data this approach allowed the proposal of recommendations, which are likely to have clinical utility.

Classification of foot ulcers in people with diabetes: A systematic review

BACKGROUND

Classification and scoring systems can help both clinical management and audit the outcomes of routine care.

AIM

This study aimed to assess published systems used to characterise ulcers in people with diabetes to determine which should be recommended to (a) aid communication between health professionals, (b) predict clinical outcome of individual ulcers, (c) characterise people with infection and/or peripheral arterial disease, and (d) audit to compare outcomes in different populations. This systematic review is part of the process of developing the 2023 guidelines to classify foot ulcers from the International Working Group on Diabetic Foot.

METHODS

We searched PubMed, Scopus and Web of Science for articles published up to December 2021 which evaluated the association, accuracy or reliability of systems used to classify ulcers in people with diabetes. Published classifications had to have been validated in populations of >80% of people with diabetes and a foot ulcer.

RESULTS

We found 28 systems addressed in 149 studies. Overall, the certainty of the evidence for each classification was low or very low, with 19 (68%) of the classifications being assessed by ≤ 3 studies. The most frequently validated system was the one from Meggitt-Wagner, but the articles validating this system focused mainly on the association between the different grades and amputation. Clinical outcomes were not standardized but included ulcer-free survival, ulcer healing, hospitalisation, limb amputation, mortality, and cost.

CONCLUSION

Despite the limitations, this systematic review provided sufficient evidence to support recommendations on the use of six particular systems in specific clinical scenarios.

Ring Opening of Glycerol Cyclic Phosphates Leads to a Diverse Array of Potentially Prebiotic Phospholipids

Phospholipids are the primary constituents of cell membranes across all domains of life, but how and when phospholipids appeared on early Earth remains unknown. Pressingly, most prebiotic syntheses of complex phospholipids rely upon substrates not yet shown to have been available on early Earth. Here, we describe potentially prebiotic syntheses of a diverse array of complex phospholipids and their building blocks. First, we show that choline could have been produced on early Earth by stepwise N-methylation of ethanolamine. Second, taking a systems chemistry approach, we demonstrate that the intrinsically activated glycerol-2,3-cyclic phosphate undergoes ring opening with combinations of prebiotic amino alcohols to yield complex phospholipid headgroups. Importantly, this pathway selects for the formation of 2-amino alcohol-bearing phospholipid headgroups and enables the accumulation of their natural regioisomers. Finally, we show that the dry-state ring opening of cyclic lysophosphatidic acids leads to a range of self-assembling lysophospholipids. Our results provide new prebiotic routes to key intermediates on the way toward modern phospholipids and illuminate the potential origin and evolution of cell membranes.

Targeted photodynamic therapy for breast cancer: the potential of glyconanoparticles

Photodynamic therapy (PDT) uses a non-toxic light sensitive molecule, a photosensitiser, that releases cytotoxic reactive oxygen species upon activation with light of a specific wavelength. Here, glycan-modified 16 nm gold nanoparticles (glycoAuNPs) were explored for their use in targeted PDT, where the photosensitiser was localised to the target cell through selective glycan-lectin interactions. Polyacrylamide (PAA)-glycans were chosen to assess glycan binding to the cell lines. These PAA-glycans indicated the selective uptake of a galactose-derivative PAA by two breast cancer cell lines, SK-BR-3 and MDA-MD-231. Subsequently, AuNPs were modified with a galactose-derivative ligand and an amine derivate of the photosensitiser chlorin e6 was incorporated to the nanoparticle surface via amide bond formation using EDC/NHS coupling chemistry. The dual modified nanoparticles were investigated for the targeted cell killing of breast cancer cells, demonstrating the versatility of using glycoAuNPs for selective binding to different cancer cells and their potential use for targeted PDT.

STrain Analysis and Mapping of the Plantar Surface (STAMPS): A novel technique of plantar load analysis during gait

Diabetic foot ulceration is driven by peripheral neuropathy, resulting in abnormal foot biomechanics and elevated plantar load. Plantar load comprises normal pressure and tangential shear stress. Currently, there are no in-shoe devices measuring both components of plantar load. The STAMPS (STrain Analysis and Mapping of the Plantar Surface) system was developed to address this and utilises digital image correlation (DIC) to determine the strain sustained by a plastically deformable insole, providing an assessment of plantar load at the foot-surface interface during gait. STAMPS was developed as a multi-layered insole, comprising a deformable mid-layer, onto which a stochastic speckle pattern film is applied. A custom-built imaging platform is used to obtain high resolution pre- and post-walking images. Images are imported into commercially available DIC software (GOM Correlate, 2020) to obtain pointwise strain data. The strain and displacement data are exported and post-processed with custom analysis routines (MATLAB, Mathworks Inc.), to obtain the resultant global and regional peak strain (SMAG), antero-posterior strain (SAP) and medio-lateral strain (SML). To validate the core technique an experimental test process used a Universal Mechanical Tester (UMT) system (UMT TriboLab, Bruker) to apply controlled vertical and tangential load regimes to the proposed multi-layer insole. A pilot study was then conducted to assess the efficacy of using the STAMPS system to measure in-shoe plantar strain in three healthy participants. Each participant walked 10 steps on the STAMPS insole using a standardised shoe. They also walked 10 m in the same shoe using a plantar pressure measurement insole (Novel Pedar®) to record peak plantar pressure (PPP) as a gold-standard comparator. The results of the experimental validation tests show that with increased normal force, at a constant shear distance, SMAG increased in a linear fashion. Furthermore, they showed that with increased shear distance, at a constant force, SMAG increased. The results of the pilot study found participant 1 demonstrated greatest SMAG in the region toes 3-5 (15.31%). The highest mean SMAG for participant 2 was at the hallux (29.31%). Participant 3 exhibited highest strain in the regions of the first and second metatarsal heads (58.85% and 41.62% respectively). Increased PPP was strongly associated with increased SMAG with a Spearman's correlation coefficient 0.673 (p < 0.0001). This study has demonstrated the efficacy of a novel method to assess plantar load across the plantar surface of the foot. Experimental testing validated the sensitivity of the method to both normal pressure and tangential shear stress. This technique was successfully incorporated into the STAMPS insole to reliably measure and quantify the cumulative degree of strain sustained by a plastically deformable insole during a period of gait, which can be used to infer plantar loading patterns. Future work will explore how these measures relate to different pathologies, such as regions at risk of diabetic foot ulceration.

Prebiotic Synthesis of N-Formylaminonitriles and Derivatives in Formamide

Amino acids and their derivatives were probably instrumental in the transition of prebiotic chemistry to early biology. Accordingly, amino acid formation under prebiotic conditions has been intensively investigated. Unsurprisingly, most of these studies have taken place with water as the solvent. Herein, we describe an investigation into the formation and subsequent reactions of aminonitriles and their formylated derivatives in formamide. We find that N-formylaminonitriles form readily from aldehydes and cyanide in formamide, even in the absence of added ammonia, suggesting a potentially prebiotic source of amino acid derivatives. Alkaline processing of N-formylaminonitriles proceeds with hydration at the nitrile group faster than deformylation, protecting aminonitrile derivatives from reversion of the Strecker condensation equilibrium during hydration/hydrolysis and furnishing mixtures of N-formylated and unformylated amino acid derivatives. Furthermore, the facile synthesis of N-formyldehydroalanine nitrile is observed in formamide from glycolaldehyde and cyanide without intervention. Dehydroalanine derivatives have been proposed as important compounds for prebiotic peptide synthesis, and we demonstrate both a synthesis suggesting that they are potentially plausible components of a prebiotic inventory, and reactions showing their utility as abiotic precursors to a range of compounds of prebiological interest.

Mechanism of rotenone binding to respiratory complex I depends on ligand flexibility

Respiratory complex I is a major cellular energy transducer located in the inner mitochondrial membrane. Its inhibition by rotenone, a natural isoflavonoid, has been used for centuries by indigenous peoples to aid in fishing and, more recently, as a broad-spectrum pesticide or even a possible anticancer therapeutic. Unraveling the molecular mechanism of rotenone action will help to design tuned derivatives and to understand the still mysterious catalytic mechanism of complex I. Although composed of five fused rings, rotenone is a flexible molecule and populates two conformers, bent and straight. Here, a rotenone derivative locked in the straight form was synthesized and found to inhibit complex I with 600-fold less potency than natural rotenone. Large-scale molecular dynamics and free energy simulations of the pathway for ligand binding to complex I show that rotenone is more stable in the bent conformer, either free in the membrane or bound to the redox active site in the substrate-binding Q-channel. However, the straight conformer is necessary for passage from the membrane through the narrow entrance of the channel. The less potent inhibition of the synthesized derivative is therefore due to its lack of internal flexibility, and interconversion between bent and straight forms is required to enable efficient kinetics and high stability for rotenone binding. The ligand also induces reconfiguration of protein loops and side-chains inside the Q-channel similar to structural changes that occur in the open to closed conformational transition of complex I. Detailed understanding of ligand flexibility and interactions that determine rotenone binding may now be exploited to tune the properties of synthetic derivatives for specific applications.

Oral 11β-HSD1 inhibitor AZD4017 improves wound healing and skin integrity in adults with type 2 diabetes mellitus: a pilot randomized controlled trial

BACKGROUND

Chronic wounds (e.g. diabetic foot ulcers) reduce the quality of life, yet treatments remain limited. Glucocorticoids (activated by the enzyme 11β-hydroxysteroid dehydrogenase type 1, 11β-HSD1) impair wound healing.

OBJECTIVES

Efficacy, safety, and feasibility of 11β-HSD1 inhibition for skin function and wound healing.

DESIGN

Investigator-initiated, double-blind, randomized, placebo-controlled, parallel-group phase 2b pilot trial.

METHODS

Single-center secondary care setting. Adults with type 2 diabetes mellitus without foot ulcers were administered 400 mg oral 11β-HSD1 inhibitor AZD4017 (n = 14) or placebo (n = 14) bi-daily for 35 days. Participants underwent 3-mm full-thickness punch skin biopsies at baseline and on day 28; wound healing was monitored after 2 and 7 days. Computer-generated 1:1 randomization was pharmacy-administered. Analysis was descriptive and focused on CI estimation. Of the 36 participants screened, 28 were randomized.

RESULTS

Exploratory proof-of-concept efficacy analysis suggested AZD4017 did not inhibit 24-h ex vivoskin 11β-HSD1 activity (primary outcome; difference in percentage conversion per 24 h 1.1% (90% CI: -3.4 to 5.5) but reduced systemic 11β-HSD1 activity by 87% (69-104%). Wound diameter was 34% (7-63%) smaller with AZD4017 at day 2, and 48% (12-85%) smaller after repeat wounding at day 30. AZD4017 improved epidermal integrity but modestly impaired barrier function. Minimal adverse events were comparable to placebo. Recruitment rate, retention, and data completeness were 2.9/month, 27/28, and 95.3%, respectively.

CONCLUSION

A phase 2 trial is feasible, and preliminary proof-of-concept data suggests AZD4017 warrants further investigation in conditions of delayed healing, for example in diabetic foot ulcers.

SIGNIFICANCE STATEMENT

Stress hormone activation by the enzyme 11β-HSD type 1 impairs skin function (e.g. integrity) and delays wound healing in animal models of diabetes, but effects in human skin were previously unknown. Skin function was evaluated in response to treatment with a 11β-HSD type 1 inhibitor (AZD4017), or placebo, in people with type 2 diabetes. Importantly, AZD4017 was safe and well tolerated. This first-in-human randomized, controlled, clinical trial found novel evidence that 11β-HSD type 1 regulates skin function in humans, including improved wound healing, epidermal integrity, and increased water loss. Results warrant further studies in conditions of impaired wound healing, for example, diabetic foot ulcers to evaluate 11β-HSD type 1 as a novel therapeutic target forchronic wounds.

Plantar shear stress in the diabetic foot: A systematic review and meta-analysis

AIMS

Diabetic foot ulceration (DFU) is a multifactorial process involving undetected, repetitive trauma resulting in inflammation and tissue breakdown. Shear stress forms a major part of plantar load, the aim of this review is to determine whether elevated shear stress results in ulceration.

METHODS

A systematic review of the Ovid Medline, EMBASE, CINAHL and Cochrane library databases was performed. Studies involving patients with diabetes who underwent plantar shear stress assessment were included. The primary outcome was plantar shear stress in patients with diabetes who had a current/previous DFU compared with those with no prior ulceration. Meta-analysis was performed comparing shear stress between those with a current or previous DFU and those without, and those with diabetes and healthy controls.

RESULTS

The search strategy identified 1461 potentially relevant articles, 16 studies met the inclusion criteria, involving a total of 597 patients. Comparing shear stress between the current/previous DFU group and those without: Standardised mean difference (SMD) 0.62 (95% CI -0.01 to 1.25), in favour of greater shear stress within the DFU group, p = 0.05. Comparing shear stress between people with diabetes and healthy controls: 0.36 (95% CI -0.31 to 1.03), in favour of greater shear stress within the diabetes group, p = 0.29.

CONCLUSION

This review suggests that that patients with diabetes and a history of ulceration exhibit greater shear stress than their ulcer-free counterparts. This strengthens the premise that development of systems to measure shear stress may be helpful in DFU prediction and prevention.

Multidisciplinary Team Decisions in Management of Abdominal Aortic Aneurysm: A Service and Quality Evaluation

Objective

To investigate whether decisions made by the multidisciplinary team (MDT) were implemented and review the MDT process to identify areas for improvement.

Methods

This was a retrospective service evaluation project. Consecutive cases of abdominal aortic aneurysm (AAA) from vascular surgery MDT meetings were reviewed. MDT outputs were extracted and compared with implemented clinical management obtained from the electronic health record (EHR) to determine concordance. Cases were re-reviewed to understand reasons why planned management was not implemented.

Results

From 42 MDT meetings, 106 patients were identified. Twenty four patients were discussed at two MDTs and four patients were discussed three times. Of the 106 patients, 91 (85.8%) were treated as planned, seven (6.6%) declined planned management and opted for conservative management, four (3.8%) patients died before treatment, and four (3.8%) had alternative management for individual reasons. Of the patients discussed multiple times, 15 (53.6%) needed review by a consultant anaesthetist or additional investigations.

Conclusion

This service evaluation found a similar proportion of cases as in existing oncology literature where the MDT decision was not implemented. However, the natural history of AAA brings nuance to this finding. Facilitating patient preference is an important problem that will require future study. This evaluation resulted in local improvements to the MDT process for AAA.

•

A small proportion of decisions made by the Vascular MDT are not implemented.

•

Incorporating patient choice into the MDT decision making process poses a challenge.

•

Patients discussed multiple times may represent complexity of comorbidities.

Prebiotic Photochemical Coproduction of Purine Ribo- and Deoxyribonucleosides

The hypothesis that life on Earth may have started with a heterogeneous nucleic acid genetic system including both RNA and DNA has attracted broad interest. The recent finding that two RNA subunits (cytidine, C, and uridine, U) and two DNA subunits (deoxyadenosine, dA, and deoxyinosine, dI) can be coproduced in the same reaction network, compatible with a consistent geological scenario, supports this theory. However, a prebiotically plausible synthesis of the missing units (purine ribonucleosides and pyrimidine deoxyribonucleosides) in a unified reaction network remains elusive. Herein, we disclose a strictly stereoselective and furanosyl-selective synthesis of purine ribonucleosides (adenosine, A, and inosine, I) and purine deoxynucleosides (dA and dI), alongside one another, via a key photochemical reaction of thioanhydroadenosine with sulfite in alkaline solution (pH 8–10). Mechanistic studies suggest an unexpected recombination of sulfite and nucleoside alkyl radicals underpins the formation of the ribo C2′–O bond. The coproduction of A, I, dA, and dI from a common intermediate, and under conditions likely to have prevailed in at least some primordial locales, is suggestive of the potential coexistence of RNA and DNA building blocks at the dawn of life.

Timescales for Prebiotic Photochemistry Under Realistic Surface Ultraviolet Conditions

Ultraviolet (UV) light has long been invoked as a source of energy for prebiotic chemical synthesis, but experimental support does not involve sources of UV light that look like the young Sun. Here we experimentally investigate whether the UV flux available on the surface of early Earth, given a favorable atmosphere, can facilitate a variety of prebiotic chemical syntheses. We construct a solar simulator for the UV light of the faint young Sun on the surface of early Earth, called StarLab. We then attempt a series of reactions testing different aspects of a prebiotic chemical scenario involving hydrogen cyanide (HCN), sulfites, and sulfides under the UV light of StarLab, including hypophosphite oxidation by UV light and hydrogen sulfide, photoreduction of HCN with bisulfite, the photoanomerization of α-thiocytidine, the production of a chemical precursor of a potentially prebiotic activating agent (nitroprusside), the photoreduction of thioanhydrouridine and thioanhydroadenosine, and the oxidation of ethanol (EtOH) by photochemically generated hydroxyl radicals. We compare the output of StarLab to the light of the faint young Sun to constrain the timescales over which these reactions would occur on the surface of early Earth. We predict that hypophosphite oxidation, HCN reduction, and photoproduction of nitroprusside would all operate on the surface of early Earth in a matter of days to weeks. The photoanomerization of α-thiocytidine would take months to complete, and the production of oxidation products from hydroxyl radicals would take years. The photoreduction of thioanhydrouridine with hydrogen sulfide did not succeed even after a long period of irradiation, providing a lower limit on the timescale of several years. The photoreduction of thioanhydroadenosine with bisulfite produced 2'-deoxyriboadenosine (dA) on the timescale of days. This suggests the plausibility of the photoproduction of purine deoxyribonucleotides, such as the photoproduction of simple sugars, proceeds more efficiently in the presence of bisulfite.

Antithrombotic therapy in diabetes: which, when, and for how long?

Cardiovascular disease remains the main cause of mortality in individuals with diabetes mellitus (DM) and also results in significant morbidity. Premature and more aggressive atherosclerotic disease, coupled with an enhanced thrombotic environment, contributes to the high vascular risk in individuals with DM. This prothrombotic milieu is due to increased platelet activity together with impaired fibrinolysis secondary to quantitative and qualitative changes in coagulation factors. However, management strategies to reduce thrombosis risk remain largely similar in individuals with and without DM. The current review covers the latest in the field of antithrombotic management in DM. The role of primary vascular prevention is discussed together with options for secondary prevention following an ischaemic event in different clinical scenarios including coronary, cerebrovascular, and peripheral artery diseases. Antiplatelet therapy combinations as well as combination of antiplatelet and anticoagulant agents are examined in both the acute phase and long term, including management of individuals with sinus rhythm and those with atrial fibrillation. The difficulties in tailoring therapy according to the variable atherothrombotic risk in different individuals are emphasized, in addition to the varying risk within an individual secondary to DM duration, presence of complications and predisposition to bleeding events. This review provides the reader with an up-to-date guide for antithrombotic management of individuals with DM and highlights gaps in knowledge that represent areas for future research, aiming to improve clinical outcome in this high-risk population.

A Mycobacterial Systems Resource for the Research Community

Functional characterization of bacterial proteins lags far behind the identification of new protein families. This is especially true for bacterial species that are more difficult to grow and genetically manipulate than model systems such as Escherichia coli and Bacillus subtilis To facilitate functional characterization of mycobacterial proteins, we have established a Mycobacterial Systems Resource (MSR) using the model organism Mycobacterium smegmatis This resource focuses specifically on 1,153 highly conserved core genes that are common to many mycobacterial species, including Mycobacterium tuberculosis, in order to provide the most relevant information and resources for the mycobacterial research community. The MSR includes both biological and bioinformatic resources. The biological resource includes (i) an expression plasmid library of 1,116 genes fused to a fluorescent protein for determining protein localization; (ii) a library of 569 precise deletions of nonessential genes; and (iii) a set of 843 CRISPR-interference (CRISPRi) plasmids specifically targeted to silence expression of essential core genes and genes for which a precise deletion was not obtained. The bioinformatic resource includes information about individual genes and a detailed assessment of protein localization. We anticipate that integration of these initial functional analyses and the availability of the biological resource will facilitate studies of these core proteins in many Mycobacterium species, including the less experimentally tractable pathogens M. abscessus, M. avium, M. kansasii, M. leprae, M. marinum, M. tuberculosis, and M. ulceransIMPORTANCE Diseases caused by mycobacterial species result in millions of deaths per year globally, and present a substantial health and economic burden, especially in immunocompromised patients. Difficulties inherent in working with mycobacterial pathogens have hampered the development and application of high-throughput genetics that can inform genome annotations and subsequent functional assays. To facilitate mycobacterial research, we have created a biological and bioinformatic resource (https://msrdb.org/) using Mycobacterium smegmatis as a model organism. The resource focuses specifically on 1,153 proteins that are highly conserved across the mycobacterial genus and, therefore, likely perform conserved mycobacterial core functions. Thus, functional insights from the MSR will apply to all mycobacterial species. We believe that the availability of this mycobacterial systems resource will accelerate research throughout the mycobacterial research community.

Peptide directed phthalocyanine-gold nanoparticles for selective photodynamic therapy of EGFR overexpressing cancers

Gold nanoparticles, covalently functionalised with the photosensitiser C11Pc and PEG, were actively targeted towards epidermal growth factor receptor overexpressing cancers using the peptide FITC-βAAEYLRK. Selective phototoxicity was observed at nanomolar concentrations with minimal dark toxicity.

Active targeting of gold nanoparticles as cancer therapeutics

Gold nanoparticles (AuNPs) are of increasing interest for their unique properties and their biocompatability, minimal toxicity, multivalency and size tunability make them exciting drug carriers. The functionalisaton of AuNPs with targeting moieties allows for their selective delivery to cancers, with antibodies, proteins, peptides, aptamers, carbohydrates and small molecules all exploited. Here, we review the recent advances in targeted-AuNPs for the treatment of cancer, with a particular focus on these classes of targeting ligands. We highlight the benefits and potential drawbacks of each ligand class and propose directions in which the field could grow.

Harnessing chemical energy for the activation and joining of prebiotic building blocks

Life is an out-of-equilibrium system sustained by a continuous supply of energy. In extant biology, the generation of the primary energy currency, adenosine 5'-triphosphate and its use in the synthesis of biomolecules require enzymes. Before their emergence, alternative energy sources, perhaps assisted by simple catalysts, must have mediated the activation of carboxylates and phosphates for condensation reactions. Here, we show that the chemical energy inherent to isonitriles can be harnessed to activate nucleoside phosphates and carboxylic acids through catalysis by acid and 4,5-dicyanoimidazole under mild aqueous conditions. Simultaneous activation of carboxylates and phosphates provides multiple pathways for the generation of reactive intermediates, including mixed carboxylic acid-phosphoric acid anhydrides, for the synthesis of peptidyl-RNAs, peptides, RNA oligomers and primordial phospholipids. Our results indicate that unified prebiotic activation chemistry could have enabled the joining of building blocks in aqueous solution from a common pool and enabled the progression of a system towards higher complexity, foreshadowing today's encapsulated peptide-nucleic acid system.

Activation chemistry drives the emergence of functionalised protocells

The complexity of the simplest conceivable cell suggests that the chemistry of prebiotic mixtures needs to be explored to understand the intricate network of prebiotic reactions that led to the emergence of life. Early cells probably relied upon compatible and interconnected chemistries to link RNA, peptides and membranes. Here we show that several types of vesicles, composed of prebiotically plausible mixtures of amphiphiles, spontaneously form and sustain the methyl isocyanide-mediated activation of amino acids, peptides and nucleotides. Activation chemistry also drives the advantageous conversion of reactive monoacylglycerol phosphates into inert cyclophospholipids, thus supporting their potential role as major constituents of protocells. Moreover, activation of prebiotic building blocks within fatty acid-based vesicles yields lipidated species capable of localising to and functionalising primitive membranes. Our findings describe a potentially prebiotic scenario in which the components of primitive cells undergo activation and provide new species that might have enabled an increase in the functionality of protocells.

Endovascular management of mycotic aortic aneurysms- A 20-year experience from a single UK centre

AIM

To present the authors' experience of endovascular treatment of confirmed and presumed (microbiology negative) mycotic aortic aneurysms (MAA).

MATERIALS AND METHODS

Patients undergoing endovascular aortic repair were identified retrospectively from 1998 using the radiology information system and an internally kept database until 2018. The primary aim was to assess the technical success and peri-operative morbidity and mortality. The secondary aim was to assess progression of infection, re-interventions, late mortality, and correlation to antibiotic duration pre- and post-procedure.

RESULTS

Thirty-four endovascular aortic procedures were performed for MAA, excluding aorto-enteric fistulas, inflammatory aneurysms, and infected grafts without a new aneurysm. Seventy-six percent of these were thoracic and 24% abdominal. The technical success was 100%. Additional procedures were undertaken in four patients with two requiring a further endovascular procedure. There were two inpatient aneurysm-related mortalities and no inpatient conversions to open repair. The 30-day re-admission and re-intervention rate was 0%. Blood cultures were positive in 45%. There were no secondary graft infections.

CONCLUSION

This is the largest European single-centre study. It supports endovascular management of MAA as a lower-risk alternative to open surgery with the majority of patients presenting acutely, later in life and requiring emergency management.

Hydroxylated Rotenoids Selectively Inhibit the Proliferation of Prostate Cancer Cells

Prostate cancer is one of the leading causes of cancer-related death in men. The identification of new therapeutics to selectively target prostate cancer cells is therefore vital. Recently, the rotenoids rotenone (1) and deguelin (2) were reported to selectively kill prostate cancer cells, and the inhibition of mitochondrial complex I was established as essential to their mechanism of action. However, these hydrophobic rotenoids readily cross the blood-brain barrier and induce symptoms characteristic of Parkinson's disease in animals. Since hydroxylated derivatives of 1 and 2 are more hydrophilic and less likely to readily cross the blood-brain barrier, 29 natural and unnatural hydroxylated derivatives of 1 and 2 were synthesized for evaluation. The inhibitory potency (IC50) of each derivative against complex I was measured, and its hydrophobicity (Slog10P) predicted. Amorphigenin (3), dalpanol (4), dihydroamorphigenin (5), and amorphigenol (6) were selected and evaluated in cell-based assays using C4-2 and C4-2B prostate cancer cells alongside control PNT2 prostate cells. These rotenoids inhibit complex I in cells, decrease oxygen consumption, and selectively inhibit the proliferation of prostate cancer cells, leaving control cells unaffected. The greatest selectivity and antiproliferative effects were observed with 3 and 5. The data highlight these molecules as promising therapeutic candidates for further evaluation in prostate cancer models.

Endodontic Therapy and Surgical Excision of a Chronic Suppurative Osteomyelitic Lesion in a Horse: A Case Report

A 22 year old thoroughbred gelding was presented for evaluation and treatment of chronic dental disease. The horse had a history of quidding and abnormal bit behavior. Intraoral examination revealed signs of chronic generalized gingival inflammation and severe dental caries affecting the maxillary and mandibular incisor teeth. Treatment was provided on two separate visits over an interval of four months. The first visit consisted of the surgical extraction of three unrestorable incisor teeth and restoration of six carious maxillary incisor teeth. The second visit consisted of conventional endodontic therapy on the remaining mandibular incisor teeth and the surgical removal of a chronic suppurative osteomyelitic lesion. Immediate and long term improvements in eating habits were noted. Three month follow-up examinations following completion of treatment have shown the teeth to be in functional position, the restorations intact, and the surgical site well healed.

Use of the Dental Dam in Endodontic Procedures in Dogs

The rationale and step-by-step use of the rubber dental dam for endodontic procedures in dogs is described. Two methods are employed. One requires an initial investment of less than $200; the other requires no investment by the veterinary practitioner.

A Review of Wearable Sensor Systems to Monitor Plantar Loading in the Assessment of Diabetic Foot Ulcers

Diabetes is highly prevalent throughout the world and imposes a high economic cost on countries at all income levels. Foot ulceration is one devastating consequence of diabetes, which can lead to amputation and mortality. Clinical assessment of diabetic foot ulcer (DFU) is currently subjective and limited, impeding effective diagnosis, treatment and prevention. Studies have shown that pressure and shear stress at the plantar surface of the foot plays an important role in the development of DFUs. Quantification of these could provide an improved means of assessment of the risk of developing DFUs. However, commercially-available sensing technology can only measure plantar pressures, neglecting shear stresses and thus limiting their clinical utility. Research into new sensor systems which can measure both plantar pressure and shear stresses are thus critical. Our aim in this paper is to provide the reader with an overview of recent advances in plantar pressure and stress sensing and offer insights into future needs in this critical area of healthcare. Firstly, we use current clinical understanding as the basis to define requirements for wearable sensor systems capable of assessing DFU. Secondly, we review the fundamental sensing technologies employed in this field and investigate the capabilities of the resultant wearable systems, including both commercial and research-grade equipment. Finally, we discuss research trends, ongoing challenges and future opportunities for improved sensing technologies to monitor plantar loading in the diabetic foot.

Drug screening using the sweat of a fingerprint: lateral flow detection of Δ9-tetrahydrocannabinol, cocaine, opiates and amphetamine

Here, we describe the use of a fluorescence based lateral flow competition assay for the screening of four classes of drugs, viz, Δ9-tetrahydrocannabinol (THC), cocaine (through the detection of benzoylecgonine, BZE), opiates (through the detection of morphine, MOR) and amphetamine (AMP) present in the sweat of a fingerprint. The Drug Screening Cartridge was specifically developed for fingerprint sample collection and analysis. For this study, the cut-offs were set at: 190, 90, 68 and 80 pg/fingerprint for THC, BZE, MOR and AMP, respectively. Working with three UK coroners, the Drug Screening Cartridge, together with its fluorescence reader, was applied to the detection of drugs in the sweat of a fingerprint from deceased individuals. The study shows that there was sufficient sweat present on the fingertips to enable analysis and that the Drug Screening Cartridge could detect the presence, or absence, of each drug. The presence of the drugs was confirmed using LC-MS-MS analysis of a second fingerprint sample collected simultaneously. Excellent correlation was achieved between the results obtained from the Drug Screening Cartridge and the LC-MS-MS analysis of the fingerprint samples obtained from 75 individuals. The accuracy of the results was: 99% for THC; 95% for BZE; 96% for MOR and 93% for AMP. The results obtained using the Drug Screening Cartridge were also compared to toxicological analysis of blood and urine samples with good correlation. The accuracy of the results between the Drug Screening Cartridge and blood was: 96%, 92%, 88% and 97% for THC, BZE, MOR and AMP, respectively. The comparison with urine showed an accuracy ranging between 86% and 92%. This fingerprint sample method has a collection time of just 5 s and a total analysis time of <10 mins. These results show that the lateral flow Drug Screening Cartridge is an excellent screening test to provide information on drug use from the sweat in a single fingerprint sample.

Assessment of the Utility of a Vascular Early Warning System Device in the Assessment of Peripheral Arterial Disease in Patients with Diabetes and Incompressible Vessels

BACKGROUND

The objective of this study was to assess the ability of a novel, automated Conformité Européenne marked vascular early warning system (VEWS) device to detect peripheral arterial disease in patients with incompressible ankle arteries and non-measurable ankle brachial pressure index (ABPI) secondary to diabetes.

METHODS

Recruited patients had diabetes, recent magnetic resonance angiography evidence of peripheral arterial disease (PAD), and incompressible vessels on ABPI. VEWS indices of each leg were automatically calculated by using optical infrared and red sensors applied to the foot, with readings obtained with the subject's leg both flat and elevated. Indices <1.03 and ≤0.94 were considered upper and lower diagnostic cutoff limits for PAD. Bollinger scores were calculated from the magnetic resonance angiography. A Best Bollinger Score (BBS) of <4 was defined as no significant PAD.

RESULTS

All patients had tissue loss. Per protocol analysis of 28 limbs in 14 patients: VEWS had a sensitivity of 94% and specificity 20% for the detection of PAD at <1.03 cutoff and sensitivity 89% and specificity 80% at ≤0.94 cutoff. There was a good correlation between the VEWS index and BBS (-0.637; P = 0.0003).

CONCLUSION

VEWS is a safe, simple-to-use, promising tool to assist in the diagnosis of PAD in patients with incompressible vessels due to diabetes.

Photosensitiser functionalised luminescent upconverting nanoparticles for efficient photodynamic therapy of breast cancer cells

Rose Bengal functionalised upconverting nanoparticles produce singlet oxygen via efficient FRET following NIR excitation and have been used for the photodynamic therapy treatment of breast cancer cells.

Semi-syntheses of the 11-hydroxyrotenoids sumatrol and villosinol

We describe semi-syntheses of the 11-hydroxyrotenoids sumatrol (1) and villosinol (2), starting from rotenone (5), using an oxime-directed C11-H functionalisation approach. Thus, rotenone (5) was converted into rotenone oxime (6), which gave dimeric palladacycle 7 following reaction with Na2PdCl4·3H2O. Controlled, divergent, oxidation of palladacycle 7 with either Pb(OAc)4 or K2Cr2O7 afforded the 11-acetoxylated intermediates 9 and 13, respectively, which were transformed into sumatrol (1) and villosinol (2).

Photosensitiser-gold nanoparticle conjugates for photodynamic therapy of cancer

Gold nanoparticles (AuNPs) have been extensively studied within biomedicine due to their biocompatibility and low toxicity. In particular, AuNPs have been widely used to deliver photosensitiser agents for photodynamic therapy (PDT) of cancer. Here we review the state-of-the-art for the functionalisation of the gold nanoparticle surface with both photosensitisers and targeting ligands for the active targeting of cancer cell surface receptors. From the initial use of the AuNPs as a simple carrier of the photosensitiser for PDT, the field has significantly advanced to include: the use of PEGylated modification to provide aqueous compatibility and stealth properties for in vivo use; gold metal-surface enhanced singlet oxygen generation; functionalisation of the AuNP surface with biological ligands to specifically target over-expressed receptors on the surface of cancer cells and; the creation of nanorods and nanostars to enable combined PDT and photothermal therapies. These versatile AuNPs have significantly enhanced the efficacy of traditional photosensitisers for both in vitro and in vivo cancer therapy. From this review it is apparent that AuNPs have an important future in the treatment of cancer.

A Light-Releasable Potentially Prebiotic Nucleotide Activating Agent

Investigations into the chemical origin of life have recently benefitted from a holistic approach in which possible atmospheric, organic, and inorganic systems chemistries are taken into consideration. In this way, we now report that a selective phosphate activating agent, namely methyl isocyanide, could plausibly have been produced from simple prebiotic feedstocks. We show that methyl isocyanide drives the conversion of nucleoside monophosphates to phosphorimidazolides under potentially prebiotic conditions and in excellent yields for the first time. Importantly, this chemistry allows for repeated reactivation cycles, a property long sought in nonenzymatic oligomerization studies. Further, as the isocyanide is released upon irradiation, the possibility of spatially and temporally controlled activation chemistry is thus raised.

Towards optimisation of surface enhanced photodynamic therapy of breast cancer cells using gold nanoparticle–photosensitiser conjugates

Surface enhanced fluorescence of zinc pthalocyanine-functionalised gold nanoparticles leads to a remarkable enhancement in photodynamic efficiency and cell death.

Stereocontrolled Semisyntheses of Elliptone and 12aβ-Hydroxyelliptone

Operationally simple, stereocontrolled semisyntheses of the anticancer rotenoids elliptone and 12aβ-hydroxyelliptone, isolated from Derris elliptica and Derris trifoliata, respectively, are described. Inspired by the work of Singhal, elliptone was prepared from rotenone via a dihydroxylation-oxidative cleavage, chemoselective Baeyer-Villiger oxidation, and acid-catalyzed elimination sequence. Elaboration of elliptone to 12aβ-hydroxyelliptone was achieved via a diastereoselective chromium-mediated Étard-like hydroxylation. The semisynthesis of elliptone constitutes an improvement over previous methods in terms of safety, scalability, and yield, while the first synthesis of 12aβ-hydroxyelliptone is also described.

Imaging of compartmentalised intracellular nitric oxide, induced during bacterial phagocytosis, using a metalloprotein-gold nanoparticle conjugate

Nitric oxide (NO) plays an essential role within the immune system since it is involved in the break-down of infectious agents such as viruses and bacteria. The ability to measure the presence of NO in the intracellular environment would provide a greater understanding of the pathophysiological mechanism of this important molecule. Here we report the detection of NO from the intracellular phagolysosome using a fluorescently tagged metalloprotein-gold nanoparticle conjugate. The metalloprotein cytochrome c, fluorescently tagged with an Alexa Fluor dye, was self-assembled onto gold nanoparticles to produce a NO specific nanobiosensor. Upon binding of NO, the cytochrome c protein changes conformation which induces an increase of fluorescence intensity of the tagged protein proportional to the NO concentration. The nanobiosensor was sensitive to NO in a reversible and selective manner, and exhibited a linear response at NO concentrations between 1 and 300 μM. In RAW264.7γ NO- macrophage cells, the nanobiosensor was used to detect the presence of NO that had been endogenously generated upon stimulation of the cells with interferon-γ and lipopolysaccharide, or spontaneously released following treatment of the cells with a NO donor. Significantly, the nanobiosensor was shown to be taken up by the macrophages within phagolysosomes, i.e., the precise location where the NO, together with other species, destroys bacterial infection. The nanobiosensor measured, for the first time, increasing concentrations of NO produced during combined stimulation and phagocytosis of Escherichia coli bacteria from within localised intracellular phagolysosomes, a key part of the immune system.

Targeted photodynamic therapy of breast cancer cells using lactose-phthalocyanine functionalized gold nanoparticles

Gold nanoparticles (AuNPs), which have been widely used for the delivery of photosensitizers for photodynamic therapy (PDT) of cancer, can be dispersed in aqueous solutions improving the delivery of the hydrophobic photosensitizer into the body. Furthermore, the large surface of AuNPs can be functionalized with a variety of ligands, including proteins, nucleic acids and carbohydrates, that allow selective targeting to cancer tissue. In this study, gold nanoparticles were functionalized with a mixed monolayer of a zinc phthalocyanine and a lactose derivative. For the first time, a carbohydrate was used with a dual purpose, as the stabilizing agent of the gold nanoparticles in aqueous solutions and as the targeting agent for breast cancer cells. The functionalization of the phthalocyanine-AuNPs with lactose led to the production of water-dispersible nanoparticles that are able to generate singlet oxygen and effect cell death upon irradiation. The targeting ability of lactose of the lactose-phthalocyanine functionalized AuNPs was studied in vitro towards the galectin-1 receptor on the surface of breast cancer cells. The targeting studies showed the exciting potential of lactose as a specific targeting agent for galactose-binding receptors overexpressed on breast cancer cells.

Stereocontrolled semi-syntheses of deguelin and tephrosin

We describe stereocontrolled semi-syntheses of deguelin and tephrosin, anti-cancer rotenoids isolated from Tephrosia vogelii. Firstly, we present a new two-step transformation of rotenone into rot-2'-enonic acid via a zinc-mediated ring opening of rotenone hydrobromide. Secondly, following conversion of rot-2'-enonic acid into deguelin, a chromium-mediated hydroxylation provides tephrosin as a single diastereoisomer. An Étard-like reaction mechanism is proposed to account for the stereochemical outcome. Our syntheses of deguelin and tephrosin are operationally simple, scalable and high yielding, offering considerable advantages over previous methods.

Nanostructured materials for photodynamic therapy: synthesis, characterization and in vitro activity

The influence of size and shape on the photodynamic properties of three gold-based porphyrin-loaded vehicles: spherical nanoparticles, hexahedral microparticles and cylindrical nanorods.

Location-specific immunodetection of cocaine on banknotes

A novel in-gel bioanalytical immunodetection method has been developed to determine both the presence and the location of cocaine on the surface of banknotes. The cocaine was 'fixed' to the surface of the banknote via a coating of a polyacrylamide gel matrix. Immunostaining of the immobilised cocaine on the banknote surface was performed using an anti-cocaine primary antibody, either pre-labelled with horse radish peroxidase (HRP) or in conjunction with a HRP-labelled secondary antibody. Visualisation of the location of the cocaine was achieved through chemiluminescence imaging of the banknote following application of a chemiluminescent substrate. The novel method was applied to the detection of cocaine on partial and whole banknote samples obtained from general circulation. Newly minted banknotes, with or without spiked cocaine, were used as positive and negative controls, respectively. The results obtained, for the first time, demonstrate the successful location-specific immunostaining of cocaine on banknotes. A preliminary analysis of six UK banknotes, obtained from general circulation, suggests that cocaine can be present at variable locations across the whole of the banknote.

Detection of mSiglec-E, in solution and expressed on the surface of Chinese hamster ovary cells, using sialic acid functionalised gold nanoparticles

Sialic acids are widespread in biology, fulfilling a wide range of functions. Their cognate lectin receptors - Siglecs - are equally diverse and widely distributed, with different Siglecs found within distinct populations of cells in the haemopoietic, immune and nervous systems. A convenient way to assay ligand recognition of soluble Siglecs would be useful, as would methods for the concomitant assessment of Siglec distribution on cell surfaces. Here we report the use of gold nanoparticles functionalised with a sialic acid ligand diluted with a polyethylene glycol (PEG) ligand for the plasmonic detection of a soluble form of murine Siglec-E (mSiglec-E-Fc fusion protein) and, importantly, for the specific detection of the same Siglec expressed on the surface of mammalian cells. These sialic acid functionalised nanoparticles are shown to overcome problems such as cellular cis interactions and low Siglec-ligand affinity. The gold nanoparticles were functionalised with various ratios of sialic acid : PEG ligands and the optimum ratio for the detection of murine Siglec-E was established based on the plasmonic detection of the soluble pre-complexed recombinant form of murine Siglec-E (mSiglec-E-Fc fusion protein). The optimum ratio for the detection of the fusion protein was found to be sialic acid : PEG ligands in a 50 : 50 ratio (glyconanoparticles 1). The optimised glyconanoparticles 1 were used to recognise and bind to the murine Siglec-E expressed on the surface of transfected Chinese hamster ovary cells as determined by transmission electron microscopy.

Abstract 170: Development of a Novel Protein Nanobody Detection System for Serum Soluble Lectin-like Oxidised Low Density Lipoprotein Receptor-1

Introduction: The Lectin-like Oxidised Low Density Lipoprotein (OxLDL) Receptor 1 (LOX-1) is a scavenger receptor found on vascular endothelial cells. LOX-1 is proteolysed at the cell surface and its soluble fragments (sLOX-1) are shed into the extracellular space. Clinical studies have demonstrated a link between serum sLOX-1 concentration and cardiovascular disease. Current technologies for the detection of sLOX-1 rely on costly monoclonal antibodies. Adhirons are antibody mimetics which can be directed against a wide range of molecules. We aimed to investigate whether Adhirons isolated against human sLOX-1 could be used to measure its concentration in solution.

Methods: BL21 Star DE3 Escheriae Coli underwent transformation with plasmids for 5 different cysteine-tagged Adhirons. Protein expression was induced and, following bacterial lysis, these were purified using nickel-agarose columns. The binding of Adhirons to the extracellular domain of immobilised, recombinant human LOX-1 was tested by modified direct enzyme linked immunosorbance assay (ELISA). Adhiron-based, sandwich ELISA and Chemiluminescence Enzyme Immunoassay (CLEIA) were developed to detect sLOX-1 in solution. The application of these techniques in the detection of LOX-1 in biological buffers was tested.

Results: Direct ELISA demonstrated a limit of detection (LOD) of 5 nanograms per millilitre. A complimentary binding pair of Adhirons (H 1 capture, A 1 detection and vice versa ) was identified. Colorimetry-based ELISA using these Adhirons detected sLOX-1 in phosphate buffered saline at an LOD of 150 nanograms per millilitre. CLEIA enabled a detection limit of 50 nanograms per millilitre, these results were reproduced in the presence of protein blockers (Bovine Serum Albumin, Casein).

Conclusion: These experiments demonstrate proof of concept for the use of Adhirons as a viable platform for the detection of sLOX-1 in solution. Further refinement and optimisation is needed for the detection sLOX-1 levels in human blood samples (500 - 3000 picogram per millilitre concentration) in order to relate these to human disease.

Delivery of a hydrophobic phthalocyanine photosensitizer using PEGylated gold nanoparticle conjugates for the in vivo photodynamic therapy of amelanotic melanoma

Gold nanoparticles functionalised with PEG and a phthalocyanine photosensitiser achieved 40% no tumour regrowth and complete survival followingin vivoPDT.

OfftargetFinder: a web tool for species-specific RNAi design

MOTIVATION

RNA interference (RNAi) technology is being developed as a weapon for pest insect control. To maximize the specificity that such an approach affords we have developed a bioinformatic web tool that searches the ever-growing arthropod transcriptome databases so that pest-specific RNAi sequences can be identified. This will help technology developers finesse the design of RNAi sequences and suggests which non-target species should be assessed in the risk assessment process.

AVAILABILITY AND IMPLEMENTATION

http://rnai.specifly.org

CONTACT

crobin@unimelb.edu.au.

Glyconanoparticles for colorimetric bioassays

Carbohydrate molecules are involved in many of the cellular processes that are important for life. By combining the specific analyte targeting of carbohydrates with the multivalent structure and change of solution colour as a consequence of plasmonic interactions with the aggregation of metal nanoparticles, glyconanoparticles have been used extensively for the development of bioanalytical assays. The noble metals used to create the nanocore, the methodologies used to assemble the carbohydrates on the nanoparticle surface, the carbohydrate chosen for each specific target, the length of the tether that separates the carbohydrate from the nanocore and the density of carbohydrates on the surface all impact on the structural formation of metal based glyconanoparticles. This tutorial review highlights these key components, which directly impact on the selectivity and sensitivity of the developed bioassay, for the colorimetric detection of lectins, toxins and viruses.

The synthesis of new fluorescent bichromophoric compounds as ratiometric pH probes for intracellular measurements

Three different bichromophoric compounds (1–3) containing an aminomethyl anthracene moiety linked to a second chromophore have been prepared and their fluorescent properties studied.

Cancer targeting with biomolecules: a comparative study of photodynamic therapy efficacy using antibody or lectin conjugated phthalocyanine-PEG gold nanoparticles

The functionalisation of therapeutic nanoparticle constructs with cancer-specific biomolecules can enable selective tumour accumulation and targeted treatment.

Pharmacology in peripheral arterial disease: what the interventional radiologist needs to know

Peripheral arterial disease (PAD) is a progressive disease with significant morbidity and mortality. Risk factor control, using diet and lifestyle modification, exercise, and pharmacological methods, improves symptoms and reduces associated cardiovascular events in these patients. Antiplatelet agents and anticoagulants may be used to reduce the incidence of acute events related to thrombosis. The armamentarium available for symptom relief and disease modification is discussed. Novel treatments such as therapeutic angiogenesis are in their evolutionary phase with promising preclinical data.