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1.
Virus Res ; 347: 199426, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38960003

RESUMO

Enterococci are robust Gram-positive bacteria that pose a significant threat in healthcare settings due to antibiotic resistance, with vancomycin-resistant enterococci (VRE) most prominent. To tackle this issue, bacteriophages (bacterial viruses) can be exploited as they specifically and efficiently target bacteria. Here, we successfully isolated and characterised a set of novel phages: SHEF10, SHEF11, SHEF13, SHEF14, and SHEF16 which target E. faecalis (SHEF10,11,13), or E. faecium (SHEF13, SHEF14 & SHEF16) strains including a range of clinical and VRE isolates. Genomic analysis shows that all phages are strictly lytic and diverse in terms of genome size and content, quickly and effectively lysing strains at different multiplicity of infections. Detailed analysis of the broad host-range SHEF13 phage revealed the crucial role of the enterococcal polysaccharide antigen (EPA) variable region in its infection of E. faecalis V583. In parallel, the discovery of a carbohydrate-targeting domain (CBM22) found conserved within the three phage genomes indicates a role in cell surface interactions that may be important in phage-bacterial interactons. These findings advance our comprehension of phage-host interactions and pave the way for targeted therapeutic strategies against antibiotic-resistant enterococcal infections.

2.
Clin Exp Dent Res ; 10(3): e880, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38798134

RESUMO

OBJECTIVE: To study the feasibility of using poly methyl methacrylate (PMMA) filament and fused deposition modeling (FDM) to manufacture denture bases via the development of a study that considers both conventional and additive-based manufacturing techniques. MATERIALS AND METHODS: Five sample groups were compared: heat and cold cured acrylic resins, CAD/CAM milled PMMA, 3D-printed PMMA (via FDM), and 3D-printed methacrylate resin (via stereolithography, SLA). All groups were subjected to mechanical testing (flexural strength, impact strength, and hardness), water sorption and solubility tests, a tooth bonding test, microbiological assessment, and accuracy of fit measurements. The performance of sample groups was referred to ISO 20795-1 and ISO/TS 19736. The data was analyzed using one-way ANOVA. RESULTS: Samples manufactured using FDM performed within ISO specifications for mechanical testing, water sorption, and solubility tests. However, the FDM group failed to achieve the ISO requirements for the tooth bonding test. FDM samples presented a rough surface finish which could ultimately encourage an undesirable high level of microbial adhesion. For accuracy of fit, FDM samples showed a lower degree of accuracy than existing materials. CONCLUSIONS: Although FDM samples were a cost-effective option and were able to be quickly manufactured in a reproducible manner, the results demonstrated that current recommended testing regimes for conventionally manufactured denture-based polymers are not directly applicable to additive-manufactured denture base polymers. Therefore, new standards should be developed to ensure the correct implementation of additive manufacturing techniques within denture-based fabrication workflow.


Assuntos
Resinas Acrílicas , Desenho Assistido por Computador , Bases de Dentadura , Teste de Materiais , Polimetil Metacrilato , Impressão Tridimensional , Bases de Dentadura/microbiologia , Polimetil Metacrilato/química , Resinas Acrílicas/química , Planejamento de Dentadura , Humanos , Estudos de Viabilidade , Materiais Dentários/química , Colagem Dentária/métodos , Propriedades de Superfície , Estereolitografia , Resistência à Flexão , Dureza , Solubilidade
3.
Br J Anaesth ; 132(5): 849-850, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38538514

RESUMO

Patients who undergo laparotomy for major trauma are amongst the most critically unwell patients, and they have high morbidity and mortality rates. Despite 20 yr of improvements in resuscitation practices, those who present with hypotension continue to have mortality rates of up to 50%. Currently there is no mechanism for capturing national audit data on these patients, leading to their exclusion from potential quality improvement initiatives. We argue that there is an unmet need for quality assurance in this patient cohort and outline possible mechanisms to address this.


Assuntos
Hipotensão , Laparotomia , Humanos , Auditoria Médica , Melhoria de Qualidade , Reino Unido , Estudos Retrospectivos
4.
Intensive Care Med ; 49(8): 922-933, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37470832

RESUMO

PURPOSE: This study aimed at determining whether intravenous artesunate is safe and effective in reducing multiple organ dysfunction syndrome in trauma patients with major hemorrhage. METHODS: TOP-ART, a randomized, blinded, placebo-controlled, phase IIa trial, was conducted at a London major trauma center in adult trauma patients who activated the major hemorrhage protocol. Participants received artesunate or placebo (2:1 randomization ratio) as an intravenous bolus dose (2.4 mg/kg or 4.8 mg/kg) within 4 h of injury. The safety outcome was the 28-day serious adverse event (SAE) rate. The primary efficacy outcome was the 48 h sequential organ failure assessment (SOFA) score. The per-protocol recruitment target was 105 patients. RESULTS: The trial was terminated after enrolment of 90 patients because of safety concerns. Eighty-three participants received artesunate (n = 54) or placebo (n = 29) and formed the safety population and 75 met per-protocol criteria (48 artesunate, 27 placebo). Admission characteristics were similar between groups (overall 88% male, median age 29 years, median injury severity score 22), except participants who received artesunate were more shocked (median base deficit 9 vs. 4.7, p = 0.042). SAEs occurred in 17 artesunate participants (31%) vs. 5 who received placebo (17%). Venous thromboembolic events (VTE) occurred in 9 artesunate participants (17%) vs. 1 who received placebo (3%). Superiority of artesunate was not supported by the 48 h SOFA score (median 5.5 artesunate vs. 4 placebo, p = 0.303) or any of the trial's secondary endpoints. CONCLUSION: Among critically ill trauma patients, artesunate is unlikely to improve organ dysfunction and might be associated with a higher VTE rate.


Assuntos
COVID-19 , Tromboembolia Venosa , Adulto , Humanos , Masculino , Feminino , COVID-19/epidemiologia , SARS-CoV-2 , Artesunato/efeitos adversos , Hemorragia/etiologia , Resultado do Tratamento
5.
Molecules ; 27(9)2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35566026

RESUMO

Cerium and its derivatives have been used as remedies for wounds since the early 20th century. Cerium nitrate has attracted most attention in the treatment of deep burns, followed later by reports of its antimicrobial properties. Its ability to mimic and replace calcium is presumed to be a major mechanism of its beneficial action. However, despite some encouraging results, the overall data are somewhat confusing with seemingly the same compounds yielding opposing results. Despite this, cerium nitrate is currently used in wound treatment in combination with silver sulfadiazine as Flammacérium. Cerium oxide, especially in nanoparticle form (Nanoceria), has lately captured much interest due to its antibacterial properties mediated via oxidative stress, leading to an increase of published reports. The properties of Nanoceria depend on the synthesis method, their shape and size. Recently, the green synthesis route has gained a lot of interest as an alternative environmentally friendly method, resulting in production of effective antimicrobial and antifungal nanoparticles. Unfortunately, as is the case with antibiotics, emerging bacterial resistance against cerium-derived nanoparticles is a growing concern, especially in the case of bacterial biofilm. However, diverse strategies resulting from better understanding of the biology of cerium are promising. The aim of this paper is to present the progress to date in the use of cerium compounds as antimicrobials in clinical applications (in particular wound healing) and to provide an overview of the mechanisms of action of cerium at both the cellular and molecular level.


Assuntos
Anti-Infecciosos Locais , Infecções Bacterianas , Queimaduras , Cério , Nanopartículas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Queimaduras/tratamento farmacológico , Cério/farmacologia , Cério/uso terapêutico , Humanos , Cicatrização
6.
Int J Mol Sci ; 22(21)2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-34768868

RESUMO

2-deoxy-D-Ribose (2dDR) was first identified in 1930 in the structure of DNA and discovered as a degradation product of it later when the enzyme thymidine phosphorylase breaks down thymidine into thymine. In 2017, our research group explored the development of wound dressings based on the delivery of this sugar to induce angiogenesis in chronic wounds. In this review, we will survey the small volume of conflicting literature on this and related sugars, some of which are reported to be anti-angiogenic. We review the evidence of 2dDR having the ability to stimulate a range of pro-angiogenic activities in vitro and in a chick pro-angiogenic bioassay and to stimulate new blood vessel formation and wound healing in normal and diabetic rat models. The biological actions of 2dDR were found to be 80 to 100% as effective as VEGF in addition to upregulating the production of VEGF. We then demonstrated the uptake and delivery of the sugar from a range of experimental and commercial dressings. In conclusion, its pro-angiogenic properties combined with its improved stability on storage compared to VEGF, its low cost, and ease of incorporation into a range of established wound dressings make 2dDR an attractive alternative to VEGF for wound dressing development.


Assuntos
Desoxirribose/farmacologia , Fatores de Crescimento do Endotélio Vascular/metabolismo , Cicatrização/efeitos dos fármacos , Indutores da Angiogênese/química , Animais , Bandagens/tendências , Fenômenos Fisiológicos Cardiovasculares/efeitos dos fármacos , Desoxirribose/metabolismo , Humanos , Morfogênese/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/fisiologia , Ribose/metabolismo , Ribose/farmacologia , Fatores de Crescimento do Endotélio Vascular/efeitos dos fármacos
7.
Curr Opin Anaesthesiol ; 34(4): 537-543, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34074885

RESUMO

PURPOSE OF REVIEW: Major trauma remains one of the leading causes of death worldwide with traumatic brain injury and uncontrolled traumatic bleeding as the main determinants of fatal outcome. Interestingly, the therapeutic approach to trauma-associated bleeding and coagulopathy shows differences between geographic regions, that are reflected in different guidelines and protocols. RECENT FINDINGS: This article summarizes main principles in coagulation diagnostics and compares different strategies for treatment of massive hemorrhage after trauma in different regions of the world. How would a bleeding trauma patient be managed if they got hit by the bus in the United States, United Kingdom, Germany, Switzerland, Austria, Denmark, Australia, or in Japan? SUMMARY: There are multiple coexistent treatment standards for trauma-induced coagulopathy in different countries and different trauma centers. Most of them initially follow a protocol-based approach and subsequently focus on predefined clinical and laboratory targets.


Assuntos
Transtornos da Coagulação Sanguínea , Ferimentos e Lesões , Austrália , Transtornos da Coagulação Sanguínea/etiologia , Transtornos da Coagulação Sanguínea/terapia , Alemanha , Objetivos , Hemorragia/etiologia , Hemorragia/terapia , Humanos , Japão , Reino Unido
8.
R Soc Open Sci ; 8(1): 201655, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33614095

RESUMO

Branched poly(N-isopropylacrylamide) was functionalized with Amphotericin B (AmB) at the chain ends to produce an antifungal material. The polymer showed antifungal properties against AmB-sensitive strains of Candida albicans, Fusarium keratoplasticum and Aspergillus flavus (minimal inhibitory concentration ranged from 5 to 500 µg ml-1) but was not effective against an AmB resistant strain of C. albicans nor against Candida tropicalis. The polymer end groups bound to the AmB target, ergosterol, and the fluorescence spectrum of a dye used as a solvatochromic probe, Nile red, was blue shifted indicating that segments of the polymer became desolvated on binding. The polymer was less toxic to corneal and renal epithelial cells and explanted corneal tissue than the free drug. Also, the polymer did not induce reactive oxygen species release from peripheral blood mononuclear cells, nor did it cause a substantial release of the proinflammatory cytokines, tumour necrosis factor-α and interleukin-1ß (at 0.5 mg ml-1).

9.
Emerg Top Life Sci ; 4(6): 567-580, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33269803

RESUMO

The global challenge of antimicrobial resistance is of increasing concern, and alternatives to currently used antibiotics or methods to improve their stewardship are sought worldwide. Microbial biofilms, complex 3D communities of bacteria and/or fungi, are difficult to treat with antibiotics for several reasons. These include their protective coats of extracellular matrix proteins which are difficult for antibiotics to penetrate. Nanoparticles (NP) are one way to rise to this challenge; whilst they exist in many forms naturally there has been a profusion in synthesis of these small (<100 nm) particles for biomedical applications. Their small size allows them to penetrate the biofilm matrix, and as well as some NP being inherently antimicrobial, they also can be modified by doping with antimicrobial payloads or coated to increase their effectiveness. This mini-review examines the current role of NP in treating wound biofilms and the rise in multifunctionality of NP.


Assuntos
Anti-Infecciosos , Infecção dos Ferimentos , Antibacterianos/uso terapêutico , Bactérias , Biofilmes , Humanos , Infecção dos Ferimentos/tratamento farmacológico
10.
Artigo em Inglês | MEDLINE | ID: mdl-32296691

RESUMO

The physiological wound healing process involves a cascade of events which could be affected by several factors resulting in chronic, non-healing wounds. The latter represent a great burden especially when bacterial biofilms are formed. The rise in antibiotic resistance amongst infectious microorganisms leads to the need of novel approaches to treat this clinical issue. In this context, the use of advanced biomaterials, which can enhance the physiological expression and secretion of the growth factors involved in the wound healing process, is gaining increasing attention as a robust and appealing alternative approach. Among them, mesoporous glasses are of particular interest due to their excellent textural properties and to the possibility of incorporating and releasing specific therapeutic species, such as metallic ions. One of the most attractive therapeutic ions is copper thanks to its proangiogenic and antibacterial effects. In this contribution, copper containing mesoporous glass nanoparticles were proposed as a multifunctional device to treat chronic wounds. The developed nanoparticles evidenced a very high specific surface area (740 m2/g), uniform pores of 4 nm and an almost total release of the therapeutic ion within 72 h of soaking. The produced nanoparticles were biocompatible and, when tested against Gram positive and Gram negative bacterial species, demonstrated antibacterial activity against both planktonic and biofilm bacteria in 2D cell monolayers, and in a 3D human model of infected skin. Their proangiogenic effect was tested with both the aortic ring and the chick chorioallantoic membrane assays and an increase in endothelial cell outgrowth at a concentration range between 30 and 300 ng/mL was shown. Overall, in this study biocompatible, multifunctional Cu-containing mesoporous glass nanoparticles were successfully produced and demonstrated to exert both antibacterial and proangiogenic effects.

11.
Sci Rep ; 10(1): 892, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31964969

RESUMO

Infectious diseases (exacerbated by antimicrobial resistance) cause death, loss of quality of life and economic burden globally. Materials with inherent antimicrobial properties offer the potential to reduce the spread of infection through transfer via surfaces or solutions, or to directly reduce microbial numbers in a host if used as implants. Additive Manufacturing (AM) techniques offer shorter supply chains, faster delivery, mass customisation and reduced unit costs, as well as highly complicated part geometries which are potentially harder to clean and sterilise. Here, we present a new approach to introducing antibacterial properties into AM, using Laser Sintering, by combining antimicrobial and base polymer powders prior to processing. We demonstrate that the mechanical properties of the resultant composite parts are similar to standard polymer parts and reveal the mode of the antibacterial activity. We show that antibacterial activity is modulated by the presence of obstructing compounds in different experimental media, which will inform appropriate use cases. We show that the material is not toxic to mammalian cells. This material could be quickly used for commercial products, and our approach could be adopted more generally to add new functionality to Laser Sintered parts.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Teste de Materiais/métodos , Nylons/química , Prata/química , Células Cultivadas , Liberação Controlada de Fármacos , Fibroblastos/efeitos dos fármacos , Vidro , Humanos , Lasers , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Nylons/farmacologia , Fosfatos/química , Pós , Próteses e Implantes , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/farmacocinética , Compostos de Prata/química , Espectrometria por Raios X , Staphylococcus aureus/efeitos dos fármacos , Resistência à Tração , Microtomografia por Raio-X
12.
Mater Sci Eng C Mater Biol Appl ; 103: 109764, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349470

RESUMO

Bioactive glasses (BG) are versatile materials for various biomedical applications, including bone regeneration and wound healing, due to their bone bonding, antibacterial, osteogenic, and angiogenic properties. In this study, we aimed to enhance the antibacterial activity of SiO2-CaO mesoporous bioactive glass nanoparticles (MBGN) by incorporating silver (Ag) through a surface modification approach. The modified Ag-containing nanoparticles (Ag-MBGN) maintained spherical shape, mesoporous structure, high dispersity, and apatite-forming ability after the surface functionalization. The antibacterial activity of Ag-MBGN was assessed firstly using a planktonic bacteria model. Moreover, a 3D tissue-engineered infected skin model was used for the first time to evaluate the antibacterial activity of Ag-MBGN at the usage dose of 1 mg/mL. In the planktonic bacteria model, Ag-MBGN exhibited a significant antibacterial effect against both Pseudomonas aeruginosa and Staphylococcus aureus in comparison to non-engineered (Ag-free) MBGN and the blank control. Moreover, Ag-MBGN did not show cytotoxicity towards fibroblasts at the usage dose. However, in the 3D infected skin model, Ag-MBGN only demonstrated antibacterial activity against S. aureus whereas their antibacterial action against P. aeruginosa was inhibited. In conclusion, surface modification by Ag incorporation is a feasible approach to enhance the antibacterial activity of MBGN without significantly impacting their morphology, polydispersity, and apatite-forming ability. The prepared Ag-MBGN are attractive building blocks for the development of 3D antibacterial scaffolds for tissue engineering.


Assuntos
Antibacterianos , Vidro/química , Modelos Biológicos , Nanopartículas/química , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/crescimento & desenvolvimento , Prata , Pele/microbiologia , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/crescimento & desenvolvimento , Células 3T3 , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Humanos , Camundongos , Prata/química , Prata/farmacologia
13.
Chem Commun (Camb) ; 55(66): 9765-9768, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31355394

RESUMO

Bacterial quorum sensing has been implicated in a number of pathogenic bacterial processes, such as biofilm formation, making it a crucial target for developing materials with a novel antibiotic mode of action. This paper describes poly(N-isopropyl acrylamide) that has been covalently linked, at multiple chain ends, to homoserine lactone to give a highly branched polymer functionalized with a key messenger molecule implicated in QS. This novel functional material has shown promising anti-QS activity in a Chromobacterium violaceum assay.


Assuntos
Acrilamidas/farmacologia , Chromobacterium/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Chromobacterium/fisiologia
15.
Biomater Sci ; 6(8): 2101-2109, 2018 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-29881840

RESUMO

Microbial keratitis can arise from penetrating injuries to the cornea. Corneal trauma promotes bacterial attachment and biofilm growth, which decrease the effectiveness of antimicrobials against microbial keratitis. Improved therapeutic efficacy can be achieved by reducing microbial burden prior to antimicrobial therapy. This paper assesses a highly-branched poly(N-isopropyl acrylamide) with vancomycin end groups (HB-PNIPAM-van), for reducing bacterial attachment and biofilm formation. The polymer lacked antimicrobial activity against Staphylococcus aureus, but significantly inhibited biofilm formation (p = 0.0008) on plastic. Furthermore, pre-incubation of S. aureus cells with HB-PNIPAM-van reduced cell attachment by 50% and application of HB-PNIPAM-van to infected ex vivo rabbit corneas caused a 1-log reduction in bacterial recovery, compared to controls (p = 0.002). In conclusion, HB-PNIPAM-van may be a useful adjunct to antimicrobial therapy in the treatment of corneal infections.


Assuntos
Resinas Acrílicas/farmacologia , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Córnea/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Vancomicina/farmacologia , Resinas Acrílicas/química , Antibacterianos/síntese química , Antibacterianos/química , Sobrevivência Celular/efeitos dos fármacos , Córnea/metabolismo , Lasers , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/citologia , Staphylococcus aureus/metabolismo , Propriedades de Superfície , Vancomicina/química
16.
Ann Surg ; 268(2): 348-356, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-28288070

RESUMO

OBJECTIVE: To evaluate (1) levels of the host-defense/antimicrobial peptide LL-37 in patients with trauma and hemorrhagic shock (HS) and (2) the effects of a synthetic host-defense peptide; Pep19-4LF on multiple organ failure (MOF) associated with HS. BACKGROUND: HS is a common cause of death in severely injured patients. There is no specific therapy that reduces HS-associated MOF. METHODS: (1) LL-37 was measured in 47 trauma/HS patients admitted to an urban major trauma center. (2) Male Wistar rats were submitted to HS (90 min, target mean arterial pressure: 27-32 mm Hg) or sham operation. Rats were treated with Pep19-4LF [66 (n = 8) or 333 µg/kg ·â€Šh (n = 8)] or vehicle (n = 12) for 4 hours following resuscitation. RESULTS: Plasma LL-37 was 12-fold higher in patients with trauma/HS compared to healthy volunteers. HS rats treated with Pep19-4LF (high dose) had a higher mean arterial pressure at the end of the 4-hour resuscitation period (79 ±â€Š4 vs 54 ±â€Š5 mm Hg) and less renal dysfunction, liver injury, and lung inflammation than HS rats treated with vehicle. Pep19-4LF enhanced (kidney/liver) the phosphorylation of (1) protein kinase B and (2) endothelial nitric oxide synthase. Pep19-4LF attenuated the HS-induced (1) translocation of p65 from cytosol to nucleus, (2) phosphorylation of IκB kinase on Ser, and (3) phosphorylation of IκBα on Ser resulting in inhibition of nuclear factor kappa B and formation of proinflammatory cytokines. Pep19-4LF prevented the release of tumor necrosis factor alpha caused by heparan sulfate in human mononuclear cells by binding to this damage-associated molecular pattern. CONCLUSIONS: Trauma-associated HS results in release of LL-37. The synthetic host-defense/antimicrobial peptide Pep19-4LF attenuates the organ injury/dysfunction associated with HS.


Assuntos
Anti-Infecciosos/uso terapêutico , Peptídeos Catiônicos Antimicrobianos/sangue , Insuficiência de Múltiplos Órgãos/prevenção & controle , Peptídeos/uso terapêutico , Substâncias Protetoras/uso terapêutico , Choque Hemorrágico/tratamento farmacológico , Ferimentos e Lesões/complicações , Animais , Biomarcadores/sangue , Estudos de Casos e Controles , Terapia Combinada , Humanos , Masculino , Insuficiência de Múltiplos Órgãos/etiologia , Ratos , Ratos Wistar , Ressuscitação , Choque Hemorrágico/sangue , Choque Hemorrágico/complicações , Choque Hemorrágico/diagnóstico , Resultado do Tratamento , Catelicidinas
17.
Oncotarget ; 8(56): 95648-95661, 2017 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-29221156

RESUMO

Solid tumours vary in sensitivity to the vascular disrupting agent combretastatin A-4 3-O-phosphate (CA4P), but underlying factors are poorly understood. The signaling sphingolipid, sphingosine-1-phosphate (S1P), promotes vascular barrier integrity by promoting assembly of VE-cadherin/ß-catenin complexes. We tested the hypothesis that tumour pre-treatment with S1P would render tumours less susceptible to CA4P. S1P (1µM) pretreatment attenuated an increase in endothelial cell (HUVEC) monolayer permeability induced by 10µM CA4P. Intravenously administered S1P (8mg/kg/hr for 20 minutes then 2mg/kg/hr for 40 minutes), reduced CA4P-induced (30mg/kg) blood flow shut-down in fibrosarcoma tumours in SCID mice (n≥7 per group), as measured by tumour retention of an intravenously administered fluorescent lectin. A trend towards in vivo protection was also found using laser Doppler flowmetry. Immunohistochemical staining of tumours ex vivo revealed disrupted patterns of VE-cadherin in vasculature of mice treated with CA4P, which were decreased by pretreatment with S1P. S1P treatment also stabilized N-cadherin junctions between endothelial cells and smooth muscle cells in culture, and stabilized tubulin filaments in HUVEC monolayers. We conclude that the rapid shutdown of tumour microvasculature by CA4P is due in part to disruption of adherens junctions and that S1P has a protective effect on both adherens junctions and the endothelial cell cytoskeleton.

18.
Biomacromolecules ; 18(9): 2887-2899, 2017 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-28731679

RESUMO

The behavior of a linear copolymer of N-isopropylacrylamide with pendant vancomycin functionality was compared to an analogous highly branched copolymer with vancomycin functionality at the chain ends. Highly branched poly(N-isopropylacrylamide) modified with vancomycin (HB-PNIPAM-van) was synthesized by functionalization of the HB-PNIPAM, prepared using reversible addition-fragmentation chain transfer polymerization. Linear PNIPAM with pendant vancomycin functionality (L-PNIPAM-van) was synthesized by functionalization of poly(N-isopropylacrylamide-co-vinyl benzoic acid). HB-PNIPAM-van aggregated S. aureus effectively, whereas the L-PNIPAM-van polymer did not. It was found that when the HB-PNIPAM-van was incubated with S. aureus the resultant phase transition provided an increase in the intensity of fluorescence of a solvatochromic dye, nile red, added to the system. In contrast, a significantly lower increase in fluorescence intensity was obtained when L-PNIPAM-van was incubated with S. aureus. These data showed that the degree of desolvation of HB-PNIPAM-van was much greater than the desolvation of the linear version. Using microcalorimetry, it was shown that there were no significant differences in the affinities of the polymer ligands for d-Ala-d-Ala and therefore differences in the interactions with bacteria were associated with changes in the probability of access of the polymer bound ligands to the d-Ala-d-Ala dipeptide. The data support the hypothesis that generation of polymer systems that respond to cellular targets, for applications such as cell targeting, detection of pathogens etc., requires the use of branched polymers with ligands situated at the chain ends.


Assuntos
Acrilamidas/química , Antibacterianos/química , Staphylococcus aureus/efeitos dos fármacos , Vancomicina/química , Acrilamidas/farmacologia , Antibacterianos/farmacologia , Relação Estrutura-Atividade , Vancomicina/farmacologia
19.
PLoS Med ; 14(7): e1002352, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28715416

RESUMO

BACKGROUND: Severe trauma induces a widespread response of the immune system. This "genomic storm" can lead to poor outcomes, including Multiple Organ Dysfunction Syndrome (MODS). MODS carries a high mortality and morbidity rate and adversely affects long-term health outcomes. Contemporary management of MODS is entirely supportive, and no specific therapeutics have been shown to be effective in reducing incidence or severity. The pathogenesis of MODS remains unclear, and several models are proposed, such as excessive inflammation, a second-hit insult, or an imbalance between pro- and anti-inflammatory pathways. We postulated that the hyperacute window after trauma may hold the key to understanding how the genomic storm is initiated and may lead to a new understanding of the pathogenesis of MODS. METHODS AND FINDINGS: We performed whole blood transcriptome and flow cytometry analyses on a total of 70 critically injured patients (Injury Severity Score [ISS] ≥ 25) at The Royal London Hospital in the hyperacute time period within 2 hours of injury. We compared transcriptome findings in 36 critically injured patients with those of 6 patients with minor injuries (ISS ≤ 4). We then performed flow cytometry analyses in 34 critically injured patients and compared findings with those of 9 healthy volunteers. Immediately after injury, only 1,239 gene transcripts (4%) were differentially expressed in critically injured patients. By 24 hours after injury, 6,294 transcripts (21%) were differentially expressed compared to the hyperacute window. Only 202 (16%) genes differentially expressed in the hyperacute window were still expressed in the same direction at 24 hours postinjury. Pathway analysis showed principally up-regulation of pattern recognition and innate inflammatory pathways, with down-regulation of adaptive responses. Immune deconvolution, flow cytometry, and modular analysis suggested a central role for neutrophils and Natural Killer (NK) cells, with underexpression of T- and B cell responses. In the transcriptome cohort, 20 critically injured patients later developed MODS. Compared with the 16 patients who did not develop MODS (NoMODS), maximal differential expression was seen within the hyperacute window. In MODS versus NoMODS, 363 genes were differentially expressed on admission, compared to only 33 at 24 hours postinjury. MODS transcripts differentially expressed in the hyperacute window showed enrichment among diseases and biological functions associated with cell survival and organismal death rather than inflammatory pathways. There was differential up-regulation of NK cell signalling pathways and markers in patients who would later develop MODS, with down-regulation of neutrophil deconvolution markers. This study is limited by its sample size, precluding more detailed analyses of drivers of the hyperacute response and different MODS phenotypes, and requires validation in other critically injured cohorts. CONCLUSIONS: In this study, we showed how the hyperacute postinjury time window contained a focused, specific signature of the response to critical injury that led to widespread genomic activation. A transcriptomic signature for later development of MODS was present in this hyperacute window; it showed a strong signal for cell death and survival pathways and implicated NK cells and neutrophil populations in this differential response.


Assuntos
Inflamação/imunologia , Insuficiência de Múltiplos Órgãos/diagnóstico , Insuficiência de Múltiplos Órgãos/etiologia , Insuficiência de Múltiplos Órgãos/terapia , Ferimentos e Lesões/complicações , Ferimentos e Lesões/terapia , Doença Aguda , Adulto , Análise Química do Sangue , Feminino , Citometria de Fluxo , Humanos , Inflamação/sangue , Inflamação/etiologia , Inflamação/terapia , Londres , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/imunologia , Estudos Prospectivos , Fatores de Tempo , Transcriptoma , Ferimentos e Lesões/sangue , Ferimentos e Lesões/imunologia
20.
Shock ; 47(4): 429-435, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27798537

RESUMO

BACKGROUND: Multiple organ dysfunction syndrome (MODS) is associated with poor outcomes for trauma patients. Different forms of MODS may exist and have different consequences. The ability to distinguish them clinically may have implications for prognosis and treatment. We wished to study whether prolonged MODS (PRMODS) could be observed as a distinct clinical entity to early resolving MODS (ERMODS) in critically injured patients. METHODS: Adult major trauma patients recruited to a prospective observational study at a single major trauma center were eligible for inclusion. MODS was defined as Sequential Organ Failure Assessment (SOFA) score >5; and PRMODS as lasting >7 days. Time to recovery (TTR) was calculated as the number of days before the SOFA fell below the MODS threshold (≤5). RESULTS: Five hundred ninety-five patients were enrolled of whom 285 developed ERMODS (48%) and 184 (31%) PRMODS. Organ dysfunction was more severe and protracted in PRMODS, especially in patients without brain injury (mean SOFA 11 vs. 6, Day 2, P < 0.001; TTR 17 vs. 3 days, P < 0.001). PRMODS exhibited higher rates of hepatic and renal dysfunction (84% vs. 56%; and 78% vs. 47%, P≤0.001). Patterns of recovery were distinct in hepatic, renal, and neurological systems (TTR 15 vs. 4; 20 vs. 3; and 28 vs. 7 days, P < 0.01). PRMODS was associated with higher infection and mortality rates (91% vs. 41%; and 22% vs. 7%, P < 0.001). CONCLUSION: PRMODS appears common, a distinct clinical entity, and associated with worse patient outcomes. PRMODS may represent an important endpoint for studies evaluating outcomes following trauma.


Assuntos
Insuficiência de Múltiplos Órgãos/complicações , Ferimentos e Lesões/complicações , APACHE , Adulto , Idoso , Feminino , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/mortalidade , Insuficiência de Múltiplos Órgãos/patologia , Prognóstico , Estudos Prospectivos , Índice de Gravidade de Doença , Ferimentos e Lesões/mortalidade , Ferimentos e Lesões/patologia
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