Non-surgical interventions for preventing contralateral tissue loss and amputation in dysvascular patients with a primary major lower limb amputation.

RATIONALE: Major lower limb amputation (LLA, above the ankle) is performed for people with intractable pain, life-threatening infections, or non-functional limbs. Of 7500 LLAs carried out in England between 2015 and 2018, the majority of these were performed in dysvascular patients. Dysvascularity is the absence of adequate blood supply to maintain a limb's usual function (ischaemia, usually caused by peripheral arterial disease or diabetes mellitus), ultimately leading to pain and tissue injury (ulcers, gangrene, sometimes referred to as tissue loss). Among those who undergo dysvascular LLA, 5.7% and 11.5% will likely undergo contralateral LLA at one and five years respectively, which is associated with greater disability and lower likelihood of returning to work, increasing the psychological burden to the patient and socioeconomic cost to the patient and health service. While extensive research has been carried out in the management of peripheral arterial disease and the care of diabetic feet, there are no guidelines for practice on prevention of contralateral amputation. OBJECTIVES: To assess the effects of non-surgical interventions versus placebo, no intervention, or other non-surgical interventions on contralateral limb (CLL) tissue loss and amputation in dysvascular patients with a primary major LLA. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and PEDro databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers until 20 March 2023. We also checked the references of identified studies and contacted study authors and manufacturers of relevant products. ELIGIBILITY CRITERIA: We aimed to include all randomised controlled trials (RCTs) and quasi-RCTs (e.g. randomised by birthdate) comparing the effectiveness of a non-surgical intervention with placebo, no intervention, or other non-surgical intervention, in adults with a primary major LLA due to dysvascularity. Interventions could be physical, pharmacological, educational, behavioural, or organisational, and delivered by a healthcare professional or carer. OUTCOMES: Our critical and important outcomes of interest were as follows. Critical outcomes • Incidence of new localised tissue injury or ulceration (tissue loss) of the CLL, regardless of stage or classification at given time points. • Time to the development of any localised tissue injury or ulceration (tissue loss) of the CLL, regardless of stage or classification. • Incidence of new minor amputation (through the ankle, foot, or toe(s)) of the CLL at given time points. • Time to new minor amputation (through the ankle, foot, or toe(s)) of the CLL. • Incidence of new major amputation (whole limb or partial limb, above the ankle) of the CLL at given time points. • Time to new major amputation (whole limb or partial limb, above the ankle) of the CLL. Important outcomes • Survival (time to death from all causes) at 12 months. • Patient-reported outcome measures of health-related quality of life (HRQoL) using validated scales such as the 12-item Short Form Health Survey (SF-12) and EQ-5D. • Adverse events (e.g. infections in the CLL). • Hospital readmission. RISK OF BIAS: We used Cochrane's RoB 1 tool to assess risk of bias in the included study. SYNTHESIS METHODS: We were only able to perform a narrative review due to lack of data. We reported risk ratios (RR) with 95% CIs for dichotomous outcomes. We used GRADE to assess the certainty of evidence for each outcome. INCLUDED STUDIES: We found one eligible study, which compared electrostimulation of the gastrocnemius muscle and standard rehabilitation against standard rehabilitation in 50 dysvascular amputees. SYNTHESIS OF RESULTS: There was no new incidence of tissue loss reported. The following outcomes were not reported: time to new tissue loss; time to and incidence of minor amputation; HRQoL outcomes; adverse events; and hospital readmissions. Electrostimulation was associated with a three-fold reduction in the incidence of new major amputation of the CLL (RR 0.33, 95% CI 0.04 to 2.99), although time to new major amputation was not reported. There was no difference between groups in 12-month survival (RR 1.0, 95% CI 0.85 to 1.18). We judged the overall certainty of the evidence (GRADE) as very low across all outcomes, with unclear risk of selection and detection bias and high risk of performance bias. AUTHORS' CONCLUSIONS: Despite the care of the CLL being identified as a key research priority by two separate consensus papers, there is insufficient high-quality evidence to address this priority to date. We found only a single RCT suitable for inclusion, and this study was subject to risk of bias. Contralateral limb outcomes should be recorded in future research on dysvascular amputees. Until better evidence and clearer recommendations are available, this topic is likely to remain a research priority. FUNDING: This Cochrane review had no dedicated funding. REGISTRATION: Protocol available via DOI 10.1002/14651858.CD013857.

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.

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.

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.

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.

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.

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.

A Peptide-Duocarmycin Conjugate Targeting the Thomsen-Friedenreich Antigen Has Potent and Selective Antitumor Activity.

Solid-phase synthesis allowed the rapid generation of a peptide-drug conjugate. A peptide targeting the Thomsen-Friedenreich antigen (TFα) was conjugated to the alkylating subunit of the potent cytotoxin duocarmycin SA. The compound, containing a cathepsin B cleavable linker, was shown to be active and selective against TFα expressing tumor cell lines.

Selective prebiotic formation of RNA pyrimidine and DNA purine nucleosides.

The nature of the first genetic polymer is the subject of major debate1. Although the 'RNA world' theory suggests that RNA was the first replicable information carrier of the prebiotic era-that is, prior to the dawn of life2,3-other evidence implies that life may have started with a heterogeneous nucleic acid genetic system that included both RNA and DNA4. Such a theory streamlines the eventual 'genetic takeover' of homogeneous DNA from RNA as the principal information-storage molecule, but requires a selective abiotic synthesis of both RNA and DNA building blocks in the same local primordial geochemical scenario. Here we demonstrate a high-yielding, completely stereo-, regio- and furanosyl-selective prebiotic synthesis of the purine deoxyribonucleosides: deoxyadenosine and deoxyinosine. Our synthesis uses key intermediates in the prebiotic synthesis of the canonical pyrimidine ribonucleosides (cytidine and uridine), and we show that, once generated, the pyrimidines persist throughout the synthesis of the purine deoxyribonucleosides, leading to a mixture of deoxyadenosine, deoxyinosine, cytidine and uridine. These results support the notion that purine deoxyribonucleosides and pyrimidine ribonucleosides may have coexisted before the emergence of life5.

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.

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-ßAAEYLRK. Selective phototoxicity was observed at nanomolar concentrations with minimal dark toxicity.

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.

Photodynamic therapy (PDT) is a well-established treatment of cancer in which cell toxic reactive oxygen species, including singlet oxygen (1O2), are produced by a photosensitiser drug following irradiation of a specific wavelength. Visible light is commonly used as the excitation source in PDT, although these wavelengths do have limited tissue penetration. In this research, upconverting nanoparticles (UCNPs) functionalised with the photosensitiser Rose Bengal (RB) have been designed and synthesised for PDT of breast cancer cells. The use of UCNPs shifts the required excitation wavelength for the production of 1O2 to near infrared light (NIR) thus allowing deeper tissue penetration. The system was designed to maximise the production of 1O2via efficient Förster resonance energy transfer (FRET) from the UCNPs to the photosensitiser. Highly luminescent NaYF4:Yb,Er,Gd@NaYF4 core-shell UCNPs were synthesised that exhibited two main anti-Stokes emission bands at 541 and 652 nm following 980 nm irradiation. RB was chosen as the photosensitiser since its absorption band overlaps with the green emission of the UCNPs. To achieve efficient energy transfer from the nanoparticles to the photosensitiser, the functionalised UCNPs included a short l-lysine linker to attach the RB to the nanocore yielding RB-lysine functionalised UCNPs. The efficient FRET from the UCNPs to the RB was confirmed by luminescence lifetime measurements. The light emitted by the UCNPs at 541 nm, following excitation at 980 nm, generates the 1O2via the RB. Multi-photon and confocal laser scanning microscopies confirmed the internalisation of the RB-lysine-UCNPs by SK-BR-3 breast cancer cells. Cell viability studies revealed that the RB-lysine-UCNPs induced low dark toxicity in cells prior to PDT treatment. Importantly, following irradiation at 980 nm, high levels of cell death were observed in cells loaded with the RB-lysine-UCNPs. Cell death following PDT treatment was also confirmed using propidium iodide and confocal microscopy. The high drug loading capacity (160 RB/nanoparticle) of the UCNPs, the efficient FRET from the UCNPs to the photosensitiser, the high level of accumulation inside the cells and their PDT cell kill suggest that the RB-lysine-UCNPs are promising for NIR PDT and hence suitable for the treatment of deep-lying cancer tumours.

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.

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

Gold nanoparticles (AuNPs; ca. 4 nm) were synthesised and functionalised with a mixed monolayer of polyethylene glycol (PEG) and one of two zinc phthalocyanines (ZnPcs), the difference between the two molecules was the length of the carbon chain that connects the Pc to the gold core. The chain was composed of either three (C3Pc) or eleven (C11Pc) carbon atoms. The C11Pc photosensitiser displayed higher fluorescence emission intensity than the C3Pc in solution. By contrast, the C3Pc photosensitiser exhibited higher fluorescence when bound to the surface of the AuNPs than the C11Pc, despite the shorter carbon chain which was expected to quench the fluorescence. In addition, the C3Pc nanoparticle conjugates exhibited an enhancement in the production of singlet oxygen (1O2). The metal-enhanced 1O2 production led to a remarkable photodynamic efficacy for the treatment of human breast cancer cells.

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 Semisyntheses of Elliptone and 12aß-Hydroxyelliptone.

Operationally simple, stereocontrolled semisyntheses of the anticancer rotenoids elliptone and 12aß-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 12aß-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 12aß-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.