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1.
Nature ; 593(7859): 391-398, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-34012085

RESUMEN

Coronatine and related bacterial phytotoxins are mimics of the hormone jasmonyl-L-isoleucine (JA-Ile), which mediates physiologically important plant signalling pathways1-4. Coronatine-like phytotoxins disrupt these essential pathways and have potential in the development of safer, more selective herbicides. Although the biosynthesis of coronatine has been investigated previously, the nature of the enzyme that catalyses the crucial coupling of coronafacic acid to amino acids remains unknown1,2. Here we characterize a family of enzymes, coronafacic acid ligases (CfaLs), and resolve their structures. We found that CfaL can also produce JA-Ile, despite low similarity with the Jar1 enzyme that is responsible for ligation of JA and L-Ile in plants5. This suggests that Jar1 and CfaL evolved independently to catalyse similar reactions-Jar1 producing a compound essential for plant development4,5, and the bacterial ligases producing analogues toxic to plants. We further demonstrate how CfaL enzymes can be used to synthesize a diverse array of amides, obviating the need for protecting groups. Highly selective kinetic resolutions of racemic donor or acceptor substrates were achieved, affording homochiral products. We also used structure-guided mutagenesis to engineer improved CfaL variants. Together, these results show that CfaLs can deliver a wide range of amides for agrochemical, pharmaceutical and other applications.


Asunto(s)
Amidas/metabolismo , Ligasas/química , Ligasas/metabolismo , Amidas/química , Aminoácidos/biosíntesis , Aminoácidos/química , Azospirillum lipoferum/enzimología , Azospirillum lipoferum/genética , Ácidos Carboxílicos/metabolismo , Ciclopentanos/química , Escherichia coli/genética , Escherichia coli/metabolismo , Herbicidas/química , Herbicidas/metabolismo , Indenos/química , Isoleucina/análogos & derivados , Isoleucina/biosíntesis , Isoleucina/química , Cinética , Modelos Moleculares , Pectobacterium/enzimología , Pectobacterium/genética , Pseudomonas syringae/enzimología , Pseudomonas syringae/genética
2.
Opt Express ; 32(10): 18399-18414, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38858996

RESUMEN

A spectrometer built using an external cavity pulsed quantum cascade laser is described. The spectrometer has a tuning range from 10 - 13 µm (1,000 - 769 cm-1) and is designed to target volatile organic compounds (VOCs) which often exhibit water-free molecular absorption within the region. The spectrometer utilizes a hollow silica waveguide gas cell which has an internal volume of a few millilitres, a fast response time (∼1 s), and is advantageous when only low sample volumes, similar to the cell volume, are available. Propane is used as a test gas because it is easy to handle, and its spectral profile is comparable to VOCs of interest. Its absorption in the region is primarily within the ν21 band which spans from 10.55 - 11.16 µm (948 - 896 cm-1). Spectral measurements at a range of concentrations show good linearity and an Allan deviation of absorbance values recorded over a 100-minute period indicates a minimum detectable absorbance of 3.5×10-5 at an integration time of 75 s.

3.
Org Biomol Chem ; 20(48): 9672-9678, 2022 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-36448404

RESUMEN

Activity-directed synthesis (ADS) is a structure-blind, function driven approach that can drive the discovery of bioactive small molecules. In ADS, arrays of reactions are designed and executed, and the crude product mixtures are then directly screened to identify reactions that yield bioactive products. The design of subsequent reaction arrays is then informed by the hit reactions that are discovered. In this study, algorithms for reaction array design were developed in which the reactions to be executed were selected from a large set of virtual reactions; the reactions were selected on the basis of similarity to reactions known to yield bioactive products. The algorithms were harnessed to design arrays of photoredox-catalysed alkylation reactions whose crude products were then screened for inhibition of growth of S. aureus ATCC29213. It was demonstrated that the approach enabled expansion of a series of antibacterial quinazolinones. It is envisaged that such algorithms could ultimately enable fully autonomous activity-directed molecular discovery.


Asunto(s)
Quinazolinonas , Staphylococcus aureus , Quinazolinonas/farmacología , Antibacterianos/farmacología , Catálisis , Algoritmos
4.
Chemistry ; 26(65): 14861-14865, 2020 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-32853417

RESUMEN

3-Amino-substituted saturated nitrogen heterocycles are an important subclass of ß-diamines, appearing in a number of clinical agents. Herein, we report a unified approach to these products based upon the regioselective photoredox-mediated hydroamination of enecarbamates. The amine coupling partner can encompass diverse amine types under a single set of reaction conditions, including primary alkyl amines, ammonia, aryl and heteroaryl amines, and N-H heterocycles. The method enables the synthesis of a wide range of pharmaceutically relevant building blocks.

5.
Appl Opt ; 58(24): 6474-6485, 2019 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-31503575

RESUMEN

Confocal scanning combined with low-coherence interferometry is used to provide remote refractive index and thickness measurements of transparent materials. The influence of lens aberrations in the confocal measurement is assessed through ray-trace modeling of the axial point-spread functions generated using optical configurations comprised of paired aspherics and paired achromats. Off-axis parabolic mirrors are suggested as an alternative to lenses and are shown to exhibit much more symmetric profiles provided the system numerical aperture is not too high. The modeled results compare favorably with experimental data generated using an optical instrument comprised of a broadband source and line-scan spectrometer. Refractive index and thickness measurements are made with each configuration with most mirror pairings offering better than twice the repeatability and accuracy of either lens pairing.

6.
Opt Express ; 26(3): 3604-3617, 2018 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-29401888

RESUMEN

This paper describes a technique for measuring refractive index and thickness of transparent plates using a fibre-optic low-coherence interferometer. The interferometer is used to independently measure quantities related to the phase and group refractive indices, np and ng, of the material under investigation. Additionally, the dispersion of the phase index dependent quantity is measured by taking advantage of the range of wavelengths available from a broadband source. These three quantities are related to simultaneously yield np and ng as well as the geometrical thickness t of the sample. Measurements are presented for a range of transparent materials including measurements of the ordinary and extraordinary refractive indices of a birefringent sapphire window. The mean percentage errors across all the samples tested were 0.09% for np, 0.08% for np, and 0.11% for t.

7.
Angew Chem Int Ed Engl ; 57(23): 6830-6833, 2018 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-29603527

RESUMEN

Thaxtomins are diketopiperazine phytotoxins produced by Streptomyces scabies and other actinobacterial plant pathogens that inhibit cellulose biosynthesis in plants. Due to their potent bioactivity and novel mode of action there has been considerable interest in developing thaxtomins as herbicides for crop protection. To address the need for more stable derivatives, we have developed a new approach for structural diversification of thaxtomins. Genes encoding the thaxtomin NRPS from S. scabies, along with genes encoding a promiscuous tryptophan synthase (TrpS) from Salmonella typhimurium, were assembled in a heterologous host Streptomyces albus. Upon feeding indole derivatives to the engineered S. albus strain, tryptophan intermediates with alternative substituents are biosynthesized and incorporated by the NRPS to deliver a series of thaxtomins with different functionalities in place of the nitro group. The approach described herein, demonstrates how genes from different pathways and different bacterial origins can be combined in a heterologous host to create a de novo biosynthetic pathway to "non-natural" product target compounds.


Asunto(s)
Vías Biosintéticas , Indoles/metabolismo , Péptido Sintasas/metabolismo , Piperazinas/metabolismo , Streptomyces/enzimología , Streptomyces/metabolismo , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Ingeniería Genética , Indoles/química , Péptido Sintasas/genética , Piperazinas/química , Plantas/microbiología , Salmonella typhimurium/enzimología , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Streptomyces/química , Streptomyces/genética , Triptófano Sintasa/genética , Triptófano Sintasa/metabolismo
8.
Chembiochem ; 18(4): 382-386, 2017 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-28005309

RESUMEN

ß-Methyltryptophans (ß-mTrp) are precursors in the biosynthesis of bioactive natural products and are used in the synthesis of peptidomimetic-based therapeutics. Currently ß-mTrp is produced by inefficient multistep synthetic methods. Here we demonstrate how an engineered variant of tryptophan synthase from Salmonella (StTrpS) can catalyse the efficient condensation of l-threonine and various indoles to generate ß-mTrp and derivatives in a single step. Although l-serine is the natural substrate for TrpS, targeted mutagenesis of the StTrpS active site provided a variant (ßL166V) that can better accommodate l-Thr as a substrate. The condensation of l-Thr and indole proceeds with retention of configuration at both α- and ß-positions to give (2S,3S)-ß-mTrp. The integration of StTrpS (ßL166V) with l-amino acid oxidase, halogenase enzymes and palladium chemocatalysts provides access to further d-configured and regioselectively halogenated or arylated ß-mTrp derivatives.


Asunto(s)
Ingeniería de Proteínas , Triptófano Sintasa/síntesis química , Triptófano Sintasa/metabolismo , Triptófano/metabolismo , Estructura Molecular , Mutación , Peptidomiméticos , Salmonella/enzimología , Salmonella/genética , Triptófano/química , Triptófano Sintasa/química , Triptófano Sintasa/genética
9.
Age Ageing ; 46(3): 346-348, 2017 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-27737827

RESUMEN

There is evidence that elder abuse is a significant public health problem that is destined to grow as population age. Countries are considering how best to act and this requires an understanding of the complex causal mechanisms contributing to its occurrence and the identification of effective interventions which can potentially make a difference. Previously, a high quality synthesis of evidence for policy and practice has been missing. In this paper, we describe a new Cochrane review of interventions to prevent the occurrence or reoccurrence of elder abuse. Overall, the quality of the evidence available for decision making is very low and there is little to guide practice. Amongst the interventions, there is some evidence that teaching coping skills to family carers of persons with dementia might make the situation better. We argue that poor quality and wasteful research needs to be avoided, and front-line agencies be supported in undertaking comparative evaluation of their services.


Asunto(s)
Abuso de Ancianos , Inhibidores de Glicósido Hidrolasas , Anciano , Animales , Antioxidantes , Humanos , Longevidad , Masculino , Ratones , Factor 2 Relacionado con NF-E2
10.
Cochrane Database Syst Rev ; 7: CD007077, 2016 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-27425375

RESUMEN

BACKGROUND: Breast-conserving therapy for women with breast cancer consists of local excision of the tumour (achieving clear margins) followed by radiotherapy (RT). RT is given to sterilize tumour cells that may remain after surgery to decrease the risk of local tumour recurrence. Most true recurrences occur in the same quadrant as the original tumour. Whole breast radiotherapy (WBRT) may not protect against the development of a new primary cancer developing in other quadrants of the breast. In this Cochrane review, we investigated the delivery of radiation to a limited volume of the breast around the tumour bed (partial breast irradiation (PBI)) sometimes with a shortened treatment duration (accelerated partial breast irradiation (APBI)). OBJECTIVES: To determine whether PBI/APBI is equivalent to or better than conventional or hypo-fractionated WBRT after breast-conserving therapy for early-stage breast cancer. SEARCH METHODS: We searched the Cochrane Breast Cancer Group Specialized Register (4 May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 5), MEDLINE (January 1966 to 4 May 2015), EMBASE (1980 to 4 May 2015), CINAHL (4 May 2015) and Current Contents (4 May 2015). We searched the International Standard Randomised Controlled Trial Number Register (5 May 2015), the World Health Organization's International Clinical Trials Registry Platform (4 May 2015) and ClinicalTrials.gov (17 June 2015). We searched for grey literature: OpenGrey (17 June 2015), reference lists of articles, several conference proceedings and published abstracts, and applied no language restrictions. SELECTION CRITERIA: Randomized controlled trials (RCTs) without confounding, that evaluated conservative surgery plus PBI/APBI versus conservative surgery plus WBRT. Published and unpublished trials were eligible. DATA COLLECTION AND ANALYSIS: Two review authors (BH and ML) performed data extraction and used Cochrane's 'Risk of bias' tool, and resolved any disagreements through discussion. We entered data into Review Manager 5 for analysis. MAIN RESULTS: We included seven RCTs and studied 7586 women of the 8955 enrolled.Local recurrence-free survival appeared worse for women receiving PBI/APBI compared to WBRT (hazard ratio (HR) 1.62, 95% confidence interval (CI) 1.11 to 2.35; six studies, 6820 participants, low-quality evidence). Cosmesis (physician-reported) appeared worse with PBI/APBI (odds ratio (OR) 1.51, 95% CI 1.17 to 1.95, five studies, 1720 participants, low-quality evidence). Overall survival did not differ with PBI/APBI (HR 0.90, 95% CI 0.74 to 1.09, five studies, 6718 participants, high-quality evidence).Late radiation toxicity (subcutaneous fibrosis) appeared worse with PBI/APBI (OR 6.58, 95% CI 3.08 to 14.06, one study, 766 participants, moderate-quality evidence). Acute skin toxicity appeared reduced with PBI/APBI (OR 0.04, 95% CI 0.02 to 0.09, two studies, 608 participants). Telangiectasia (OR 26.56, 95% CI 3.59 to 196.51, 1 study, 766 participants) and radiological fat necrosis (OR 1.58, 95% CI 1.02 to 2.43, three studies, 1319 participants) appeared worse with PBI/APBI. Late skin toxicity (OR 0.21, 95% CI 0.01 to 4.39, two studies, 608 participants) and breast pain (OR 2.17, 95% CI 0.56 to 8.44, one study, 766 participants) appeared not to differ with PBI/APBI.'Elsewhere primaries' (new primaries in the ipsilateral breast) appeared more frequent with PBI/APBI (OR 3.97, 95% CI 1.51 to 10.41, three studies, 3009 participants).We found no clear evidence of a difference for the comparison of PBI/APBI with WBRT for the outcomes of: cause-specific survival (HR 1.08, 95% CI 0.73 to 1.58, five studies, 6718 participants, moderate-quality evidence), distant metastasis-free survival (HR 0.94, 95% CI 0.65 to 1.37, four studies, 3267 participants, moderate-quality evidence), relapse-free survival (HR 1.36, 95% CI 0.88 to 2.09, three studies, 3811 participants), loco-regional recurrence-free survival (HR 1.80, 95% CI 1.00 to 3.25, two studies, 3553 participants) or mastectomy rates (OR 1.20, 95% CI 0.77 to 1.87, three studies, 4817 participants, low-quality evidence). Compliance was met: more than 90% of the women in all studies received the RT they were assigned to receive. We found no data for the outcomes of costs, quality of life or consumer preference. AUTHORS' CONCLUSIONS: It appeared that local recurrence and 'elsewhere primaries' (new primaries in the ipsilateral breast) are increased with PBI/APBI (the difference was small), but we found no evidence of detriment to other oncological outcomes. It appeared that cosmetic outcomes and some late effects were worse with PBI/APBI but its use was associated with less acute skin toxicity. The limitations of the data currently available mean that we cannot make definitive conclusions about the efficacy and safety or ways to deliver of PBI/APBI. We await completion of ongoing trials.


Asunto(s)
Neoplasias de la Mama/radioterapia , Tratamientos Conservadores del Órgano/métodos , Mama/efectos de la radiación , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , Terapia Combinada/métodos , Supervivencia sin Enfermedad , Femenino , Humanos , Mastectomía Segmentaria , Recurrencia Local de Neoplasia/prevención & control , Hipofraccionamiento de la Dosis de Radiación , Radioterapia/efectos adversos , Radioterapia/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto
11.
Cochrane Database Syst Rev ; (8): CD010321, 2016 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-27528431

RESUMEN

BACKGROUND: Maltreatment of older people (elder abuse) includes psychological, physical, sexual abuse, neglect and financial exploitation. Evidence suggests that 10% of older adults experience some form of abuse, and only a fraction of cases are actually reported or referred to social services agencies. Elder abuse is associated with significant morbidity and premature mortality. Numerous interventions have been implemented to address the issue of elder maltreatment. It is, however, unclear which interventions best serve to prevent or reduce elder abuse. OBJECTIVES: The objective of this review was to assess the effectiveness of primary, secondary and tertiary intervention programmes used to reduce or prevent abuse of the elderly in their own home, in organisational or institutional and community settings. The secondary objective was to investigate whether intervention effects are modified by types of abuse, types of participants, setting of intervention, or the cognitive status of older people. SEARCH METHODS: We searched 19 databases (AgeLine, CINAHL, Psycinfo, MEDLINE, Embase, Proquest Central, Social Services Abstracts , ASSIA, Sociological Abstracts, ProQuest Dissertations & Theses Global, Web of Science, LILACS, EPPI, InfoBase, CENTRAL, HMIC, Opengrey and Zetoc) on 12 platforms, including multidisciplinary disciplines covering medical, health, social sciences, social services, legal, finance and education. We also browsed related organisational websites, contacted authors of relevant articles and checked reference lists. Searches of databases were conducted between 30 August 2015 and 16 March 2016 and were not restricted by language. SELECTION CRITERIA: We included randomised controlled trials (RCTs), cluster-randomised trials, and quasi-RCTs, before-and-after studies, and interrupted time series. Only studies with at least 12 weeks of follow-up investigating the effect of interventions in preventing or reducing abuse of elderly people and those who interact with the elderly were included. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed the studies' risk of bias. Studies were categorised as: 1) education on elder abuse, 2) programmes to reduce factors influencing elder abuse, 3) specific policies for elder abuse, 4) legislation on elder abuse, 5) programmes to increase detection rate on elder abuse, 6) programmes targeted to victims of elder abuse, and 7) rehabilitation programmes for perpetrators of elder abuse. All studies were assessed for study methodology, intervention type, setting, targeted audience, intervention components and intervention intensity. MAIN RESULTS: The search and selection process produced seven eligible studies which included a total of 1924 elderly participants and 740 other people. Four of the above seven categories of interventions were evaluated by included studies that varied in study design. Eligible studies of rehabilitation programmes, specific policies for elder abuse and legislation on elder abuse were not found. All included studies contained a control group, with five of the seven studies describing the method of allocation as randomised. We used the Cochrane 'Risk of bias' tool and EPOC assessment criteria to assess risk of bias. The results suggest that risk of bias across the included body of research was high, with at least 40% of the included studies judged as being at high risk of bias. Only one study was judged as having no domains at high risk of bias, with two studies having two of 11 domains at high risk. One study was judged as being at high risk of bias across eight of 11 domains.All included studies were set in high-income countries, as determined by the World Bank economic classification (USA four, Taiwan one, UK two). None of the studies provided specific information or analysis on equity considerations, including by socio-economic disadvantage, although one study was described as being set in a housing project. One study performed some form of cost-effectiveness analysis on the implementation of their intervention programmes, although there were few details on the components and analysis of the costing.We are uncertain whether these interventions reduce the occurrence or recurrence of elder abuse due to variation in settings, measures and effects reported in the included studies, some of which were very small and at a high risk of bias (low- and very low-quality evidence).Two studies measured the occurrence of elder abuse. A high risk of bias study found a difference in the post-test scores (P value 0.048 and 0.18). In a low risk of bias study there was no difference found (adjusted odds ratio (OR) =0.48, 95% 0.18 to 1.27) (n = 214). For interventions measuring abuse recurrence, one small study (n = 16) reported no difference in post-test means, whilst another found higher levels of abuse reported for the intervention arms (Cox regression, combined intervention hazard ratio (HR) = 1.78, alpha level = 0.01).It is uncertain whether targeted educational interventions improve the relevant knowledge of health professionals and caregivers (very low-quality evidence), although they may improve detection of resident-to-resident abuse. The concept of measuring improvement in detection or reporting as opposed to measuring the occurrence or recurrence of abuse is complicated. An intervention of public education and support services aimed at victims may also improve rates of reporting, however it is unclear whether this was due to an increase in abuse recurrence or better reporting of abuse.The effectiveness of service planning interventions at improving the assessment and documentation of related domains is uncertain. Unintended outcomes were not reported in the studies. AUTHORS' CONCLUSIONS: There is inadequate trustworthy evidence to assess the effects of elder abuse interventions on occurrence or recurrence of abuse, although there is some evidence to suggest it may change the combined measure of anxiety and depression of caregivers. There is a need for high-quality trials, including from low- or middle-income countries, with adequate statistical power and appropriate study characteristics to determine whether specific intervention programmes, and which components of these programmes, are effective in preventing or reducing abuse episodes among the elderly. It is uncertain whether the use of educational interventions improves knowledge and attitude of caregivers, and whether such programmes also reduce occurrence of abuse, thus future research is warranted. In addition, all future research should include a component of cost-effectiveness analysis, implementation assessment and equity considerations of the specific interventions under review.


Asunto(s)
Abuso de Ancianos/prevención & control , Anciano , Cuidadores , Abuso de Ancianos/clasificación , Abuso de Ancianos/diagnóstico , Humanos , Análisis de Series de Tiempo Interrumpido , Casas de Salud , Personal de Enfermería , Prevención Primaria , Ensayos Clínicos Controlados Aleatorios como Asunto , Prevención Secundaria , Prevención Terciaria
12.
Cochrane Database Syst Rev ; 7: CD003860, 2016 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-27425588

RESUMEN

BACKGROUND: Shortening the duration of radiation therapy would benefit women with early breast cancer treated with breast conserving surgery. It may also improve access to radiation therapy by improving efficiency in radiation oncology departments globally. This can only happen if the shorter treatment is as effective and safe as conventional radiation therapy. This is an update of a Cochrane Review first published in 2008 and updated in 2009. OBJECTIVES: To assess the effect of altered radiation fraction size for women with early breast cancer who have had breast conserving surgery. SEARCH METHODS: We searched the Cochrane Breast Cancer Specialised Register (23 May 2015), CENTRAL (The Cochrane Library 2015, Issue 4), MEDLINE (Jan 1996 to May 2015), EMBASE (Jan 1980 to May 2015), the WHO International Clinical Trials Registry Platform (ICTRP) search portal (June 2010 to May 2015) and ClinicalTrials.gov (16 April 2015), reference lists of articles and relevant conference proceedings. No language or publication constraints were applied. SELECTION CRITERIA: Randomised controlled trials of altered fraction size versus conventional fractionation for radiation therapy in women with early breast cancer who had undergone breast conserving surgery. DATA COLLECTION AND ANALYSIS: Two authors performed data extraction independently, with disagreements resolved by discussion. We sought missing data from trial authors. MAIN RESULTS: We studied 8228 women in nine studies. Eight out of nine studies were at low or unclear risk of bias. Altered fraction size (delivering radiation therapy in larger amounts each day but over fewer days than with conventional fractionation) did not have a clinically meaningful effect on: local recurrence-free survival (Hazard Ratio (HR) 0.94, 95% CI 0.77 to 1.15, 7095 women, four studies, high-quality evidence), cosmetic outcome (Risk ratio (RR) 0.90, 95% CI 0.81 to 1.01, 2103 women, four studies, high-quality evidence) or overall survival (HR 0.91, 95% CI 0.80 to 1.03, 5685 women, three studies, high-quality evidence). Acute radiation skin toxicity (RR 0.32, 95% CI 0.22 to 0.45, 357 women, two studies) was reduced with altered fraction size. Late radiation subcutaneous toxicity did not differ with altered fraction size (RR 0.93, 95% CI 0.83 to 1.05, 5130 women, four studies, high-quality evidence). Breast cancer-specific survival (HR 0.91, 95% CI 0.78 to 1.06, 5685 women, three studies, high quality evidence) and relapse-free survival (HR 0.93, 95% CI 0.82 to 1.05, 5685 women, three studies, moderate-quality evidence) did not differ with altered fraction size. We found no data for mastectomy rate. Altered fraction size was associated with less patient-reported (P < 0.001) and physician-reported (P = 0.009) fatigue at six months (287 women, one study). We found no difference in the issue of altered fractionation for patient-reported outcomes of: physical well-being (P = 0.46), functional well-being (P = 0.38), emotional well-being (P = 0.58), social well-being (P = 0.32), breast cancer concerns (P = 0.94; 287 women, one study). We found no data with respect to costs. AUTHORS' CONCLUSIONS: We found that using altered fraction size regimens (greater than 2 Gy per fraction) does not have a clinically meaningful effect on local recurrence, is associated with decreased acute toxicity and does not seem to affect breast appearance, late toxicity or patient-reported quality-of-life measures for selected women treated with breast conserving therapy. These are mostly women with node negative tumours smaller than 3 cm and negative pathological margins.


Asunto(s)
Neoplasias de la Mama/radioterapia , Hipofraccionamiento de la Dosis de Radiación , Neoplasias de la Mama/cirugía , Terapia Combinada/métodos , Fraccionamiento de la Dosis de Radiación , Femenino , Humanos , Mastectomía Segmentaria , Traumatismos por Radiación/complicaciones , Traumatismos por Radiación/mortalidad , Ensayos Clínicos Controlados Aleatorios como Asunto
13.
Appl Opt ; 55(25): 6797-806, 2016 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-27607251

RESUMEN

Hollow silica waveguides (HSWs) are used to produce long path length, low-volume gas cells, and are demonstrated with quantum cascade laser spectroscopy. Absorption measurements are made using the intrapulse technique, which allows measurements to be made across a single laser pulse. Simultaneous laser light and gas coupling is achieved through the modification of commercially available gas fittings with low dead volume. Three HSW gas cell configurations with different path lengths and internal diameters are analyzed and compared with a 30 m path length astigmatic Herriott cell. Limit of detection measurements are made for the gas cells using methane at a wavelength 7.82 µm. The lowest limit of detection was provided by HSW with a bore diameter of 1000 µm and a path length of 5 m and was measured to be 0.26 ppm, with a noise equivalent absorbance of 4.1×10-4. The long-term stability of the HSW and Herriott cells is compared through analysis of the Allan-Werle variance of data collected over a 24 h period. The response times of the HSW and Herriott cells are measured to be 0.8 s and 36 s, respectively.

14.
Cochrane Database Syst Rev ; 1: CD008366, 2015 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-25556970

RESUMEN

BACKGROUND: Multi-strategic community wide interventions for physical activity are increasingly popular but their ability to achieve population level improvements is unknown. OBJECTIVES: To evaluate the effects of community wide, multi-strategic interventions upon population levels of physical activity. SEARCH METHODS: We searched the Cochrane Public Health Group Segment of the Cochrane Register of Studies,The Cochrane Library, MEDLINE, MEDLINE in Process, EMBASE, CINAHL, LILACS, PsycINFO, ASSIA, the British Nursing Index, Chinese CNKI databases, EPPI Centre (DoPHER, TRoPHI), ERIC, HMIC, Sociological Abstracts, SPORT Discus, Transport Database and Web of Science (Science Citation Index, Social Sciences Citation Index, Conference Proceedings Citation Index). We also scanned websites of the EU Platform on Diet, Physical Activity and Health; Health-Evidence.org; the International Union for Health Promotion and Education; the NIHR Coordinating Centre for Health Technology (NCCHTA); the US Centre for Disease Control and Prevention (CDC) and NICE and SIGN guidelines. Reference lists of all relevant systematic reviews, guidelines and primary studies were searched and we contacted experts in the field. The searches were updated to 16 January 2014, unrestricted by language or publication status. SELECTION CRITERIA: Cluster randomised controlled trials, randomised controlled trials, quasi-experimental designs which used a control population for comparison, interrupted time-series studies, and prospective controlled cohort studies were included. Only studies with a minimum six-month follow up from the start of the intervention to measurement of outcomes were included. Community wide interventions had to comprise at least two broad strategies aimed at physical activity for the whole population. Studies which randomised individuals from the same community were excluded. DATA COLLECTION AND ANALYSIS: At least two review authors independently extracted the data and assessed the risk of bias. Each study was assessed for the setting, the number of included components and their intensity. The primary outcome measures were grouped according to whether they were dichotomous (per cent physically active, per cent physically active during leisure time, and per cent physically inactive) or continuous (leisure time physical activity time (time spent)), walking (time spent), energy expenditure (as metabolic equivalents or METS)). For dichotomous measures we calculated the unadjusted and adjusted risk difference, and the unadjusted and adjusted relative risk. For continuous measures we calculated percentage change from baseline, unadjusted and adjusted. MAIN RESULTS: After the selection process had been completed, 33 studies were included. A total of 267 communities were included in the review (populations between 500 and 1.9 million). Of the included studies, 25 were set in high income countries and eight were in low income countries. The interventions varied by the number of strategies included and their intensity. Almost all of the interventions included a component of building partnerships with local governments or non-governmental organisations (NGOs) (29 studies). None of the studies provided results by socio-economic disadvantage or other markers of equity. However, of those included studies undertaken in high income countries, 14 studies were described as being provided to deprived, disadvantaged or low socio-economic communities. Nineteen studies were identified as having a high risk of bias, 10 studies were unclear, and four studies had a low risk of bias. Selection bias was a major concern with these studies, with only five studies using randomisation to allocate communities. Four studies were judged as being at low risk of selection bias although 19 studies were considered to have an unclear risk of bias. Twelve studies had a high risk of detection bias, 13 an unclear risk and four a low risk of bias. Generally, the better designed studies showed no improvement in the primary outcome measure of physical activity at a population level.All four of the newly included, and judged to be at low risk of bias, studies (conducted in Japan, United Kingdom and USA) used randomisation to allocate the intervention to the communities. Three studies used a cluster randomised design and one study used a stepped wedge design. The approach to measuring the primary outcome of physical activity was better in these four studies than in many of the earlier studies. One study obtained objective population representative measurements of physical activity by accelerometers, while the remaining three low-risk studies used validated self-reported measures. The study using accelerometry, conducted in low income, high crime communities of USA, emphasised social marketing, partnership with police and environmental improvements. No change in the seven-day average daily minutes of moderate to vigorous physical activity was observed during the two years of operation. Some program level effect was observed with more people walking in the intervention community, however this result was not evident in the whole community. Similarly, the two studies conducted in the United Kingdom (one in rural villages and the other in urban London; both using communication, partnership and environmental strategies) found no improvement in the mean levels of energy expenditure per person per week, measured from one to four years from baseline. None of the three low risk studies reporting a dichotomous outcome of physical activity found improvements associated with the intervention.Overall, there was a noticeable absence of reporting of benefit in physical activity for community wide interventions in the included studies. However, as a group, the interventions undertaken in China appeared to have the greatest possibility of success with high participation rates reported. Reporting bias was evident with two studies failing to report physical activity measured at follow up. No adverse events were reported.The data pertaining to cost and sustainability of the interventions were limited and varied. AUTHORS' CONCLUSIONS: Although numerous studies have been undertaken, there is a noticeable inconsistency of the findings in the available studies and this is confounded by serious methodological issues within the included studies. The body of evidence in this review does not support the hypothesis that the multi-component community wide interventions studied effectively increased physical activity for the population, although some studies with environmental components observed more people walking.


Asunto(s)
Ejercicio Físico , Implementación de Plan de Salud/métodos , Promoción de la Salud/métodos , Evaluación de Programas y Proyectos de Salud , Acelerometría/instrumentación , Ciudades , Características Culturales , Promoción de la Salud/estadística & datos numéricos , Humanos , Ensayos Clínicos Controlados Aleatorios como Asunto , Sesgo de Selección , Autoinforme
15.
Cochrane Database Syst Rev ; (6): CD007077, 2014 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-24938937

RESUMEN

BACKGROUND: Breast conserving therapy for women with breast cancer consists of local excision of the tumour (achieving clear margins) followed by radiation therapy (RT). RT is given to sterilize tumour cells that may remain after surgery to decrease the risk of local tumour recurrence. Most true recurrences occur in the same quadrant as the original tumour. Whole breast RT may not protect against the development of a new primary cancer developing in other quadrants of the breast. In this Cochrane Review, we investigated the role of delivering radiation to a limited volume of the breast around the tumour bed (partial breast irradiation: PBI) sometimes with a shortened treatment duration (accelerated partial breast irradiation: APBI). OBJECTIVES: To determine whether PBI/APBI is equivalent to or better than conventional or hypofractionated WBRT after breast conservation therapy for early-stage breast cancer. SEARCH METHODS: We searched the Cochrane Breast Cancer Group Specialised Register (07 November 2013), CENTRAL (2014, Issue 3), MEDLINE (January 1966 to 11 April 2014), EMBASE (1980 to 11 April 2014), CINAHL (11 April 2014) and Current Contents (11 April 2014). Also we searched the International Standard Randomised Controlled Trial Number Register, the World Health Organization's International Clinical Trials Registry Platform (07 November 2013) and US clinical trials registry (www.clinicaltrials.gov) (22 April 2014). We searched for grey literature: Open Grey (23 April 2014), reference lists of articles, a number of conference proceedings and published abstracts, and did not apply any language restrictions. SELECTION CRITERIA: Randomised controlled trials (RCTs) without confounding and evaluating conservative surgery plus PBI/APBI versus conservative surgery plus whole breast RT. We included both published and unpublished trials. DATA COLLECTION AND ANALYSIS: Three review authors (ML, DF and BH) performed data extraction and resolved any disagreements through discussion. We entered data into Review Manager for analysis. BH and ML assessed trials, graded the methodological quality using Cochrane's Risk of Bias tool and resolved any disagreements through discussion. MAIN RESULTS: We included four RCTs that had 2253 women. Two older trials examined RT techniques which do not reflect current practice and one trial had a short follow-up. We downgraded the quality of the evidence for our key outcomes due to risk of bias. Taken together with other GRADE recommendations, the quality of evidence for our outcomes was very low to low. For the comparison of partial breast irradiation/accelerated breast irradiation (PBI/APBI) with whole breast irradiation (WBRT), local recurrence-free survival appeared worse (Hazard Ratio (HR) 1.74, 95% confidence interval (CI) 1.23 to 2.45; three trials, 1140 participants, very low quality evidence). Cosmesis appeared improved with PBI/APBI in a single trial (OR 0.40, 95% CI 0.23 to 0.72; one trial, 241 participants, very low quality evidence), but late toxicity (telangiectasia OR 4.41, 95% CI 3.21 to 6.05; very low quality evidence, 708 participants) and subcutaneous fibrosis (OR 4.27, 95% CI 3.04 to 6.01; one trial, 710 participants, very low quality evidence) appeared increased in another trial. We found no clear evidence of a difference for the comparison of PBI/APBI versus WBRT for the outcomes of: overall survival (HR 0.99, 95% CI 0.83 to 1.18; three trials, 1140 participants, very low quality evidence), cause-specific survival (HR 0.95, 95% CI 0.74 to 1.22; two trials, 966 participants, low evidence quality), distant metastasis-free survival (HR 1.02, 95% CI 0.81 to 1.28; 1140 participants, low quality evidence), subsequent mastectomy rate (OR 0.20, 95% CI 0.01 to 4.21; 258 participants, low quality evidence) and relapse-free survival (HR 0.99, 95% CI 0.53 to 1.85; 258 participants, low quality evidence). We found no data for the outcomes of acute toxicity, new ipsilateral breast primaries, costs, quality of life or consumer preference. AUTHORS' CONCLUSIONS: The limitations of the data currently available mean that we cannot make definitive conclusions about the efficacy and safety or ways to deliver of PBI/APBI. We await completion of ongoing trials.


Asunto(s)
Neoplasias de la Mama/radioterapia , Tratamientos Conservadores del Órgano/métodos , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , Terapia Combinada/métodos , Supervivencia sin Enfermedad , Femenino , Humanos , Mastectomía Segmentaria , Recurrencia Local de Neoplasia/prevención & control , Radioterapia/efectos adversos , Radioterapia/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto
16.
Cochrane Database Syst Rev ; (4): CD005212, 2013 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-23633328

RESUMEN

BACKGROUND: After surgery for localised breast cancer, radiotherapy (RT) improves both local control and breast cancer-specific survival. In patients at risk of harbouring micro-metastatic disease, adjuvant chemotherapy (CT) improves 15-year survival. However, the best sequence of administering these two types of adjuvant therapy for early-stage breast cancer is unclear. OBJECTIVES: To determine the effects of different sequencing of adjuvant CT and RT for women with early breast cancer. SEARCH METHODS: An updated search was carried out in the Cochrane Breast Cancer Group's Specialised Register (20 May 2011), MEDLINE (14 December 2011), EMBASE (20 May 2011) and World Health Organization (WHO) International Clinical Trials Registry Platform (20 May 2011). Details of the search strategy and methods of coding for the Specialised Register are described in the Group's module in The Cochrane Library. We extracted studies that had been coded as 'early', 'chemotherapy' and 'radiotherapy'. SELECTION CRITERIA: We included randomised controlled trials evaluating different sequencing of CT and RT. DATA COLLECTION AND ANALYSIS: We assessed the eligibility and quality of the identified studies and extracted data from the published reports of the included trials. We derived odds ratios (OR) and hazard ratios (HR) from the available numerical data. Toxicity data were extracted, where reported. We used a fixed-effect model for meta-analysis and conducted analyses on the basis of the method of sequencing of the two treatments. MAIN RESULTS: Three trials reporting two different sequencing comparisons were identified. There were no significant differences between the various methods of sequencing adjuvant therapy for local recurrence-free survival, overall survival, relapse-free survival and metastasis-free survival based on 1166 randomised women in three trials. Concurrent chemoradiation increased anaemia (OR 1.54; 95% confidence interval (CI) 1.10 to 2.15), telangiectasia (OR 3.85; 95% CI 1.37 to 10.87) and pigmentation (OR 15.96; 95% CI 2.06 to 123.68). Treated women did not report worse cosmesis with concurrent chemoradiation but physician-reported assessments did (OR 1.14; 95% CI 0.42 to 3.07). Other measures of toxicity did not differ between the two types of sequencing. On the basis of one trial (244 women), RT before CT was associated with an increased risk of neutropenic sepsis (OR 2.96; 95% CI 1.26 to 6.98) compared with CT before RT, but other measures of toxicity did not differ. AUTHORS' CONCLUSIONS: The data included in this review, from three well-conducted randomised trials, suggest that different methods of sequencing CT and RT do not appear to have a major effect on recurrence or survival for women with breast cancer if RT is commenced within seven months after surgery.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/radioterapia , Quimioterapia Adyuvante/métodos , Radioterapia Adyuvante/métodos , Anemia/etiología , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/cirugía , Quimioterapia Adyuvante/efectos adversos , Femenino , Humanos , Trastornos de la Pigmentación/etiología , Radioterapia Adyuvante/efectos adversos , Ensayos Clínicos Controlados Aleatorios como Asunto , Telangiectasia/etiología , Factores de Tiempo
17.
Cochrane Database Syst Rev ; (8): CD006861, 2013 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-23979995

RESUMEN

BACKGROUND: People living with end-stage kidney disease (ESKD) often develop anaemia. Erythropoiesis-simulating agents (ESAs) are often given to people living with ESKD to maintain haemoglobin at a level to minimise need for transfusion. However, about 5% to 10% of patients with ESKD exhibit resistance to ESAs, and observational studies have shown that patients requiring high doses of ESA are at increased risk of mortality. OBJECTIVES: This review aimed to study the effects of interventions for the treatment of ESA-resistant anaemia in people with ESKD. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE for randomised controlled trials (RCT) that involved participants with ESKD on dialysis or who were pre-dialysis patients with chronic kidney disease (stage 5). Date of last search: April 2013. SELECTION CRITERIA: ESA resistance was defined as failure to achieve or maintain haemoglobin/haematocrit levels within the desired target range despite appropriate ESA doses (erythropoietin ≥ 450 U/kg/wk intravenously or ≥ 300 U/kg/wk subcutaneously; darbepoetin ≥ 1.5 µg/kg/wk) in people who were not nutritionally deficient, or who had haematological or bleeding disorders. Extended inclusion criteria for ESA hyporesponsive state were: erythropoietin dose ≥ 300 U/kg/wk and ≥ 150 U/kg/wk for intravenous administration; or ≥ 200 U/kg/wk and ≥ 100 U/kg/wk for subcutaneous administration; or darbepoetin dose ≥ 1.0 µg/kg/wk). DATA COLLECTION AND ANALYSIS: Two authors independently assessed study quality and extracted data. Statistical analyses were performed using a random effects model and results expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI). MAIN RESULTS: Titles and abstracts of 521 records were screened, of which we reviewed 99 from the full text. Only two studies matched our inclusion criteria. One study compared intravenous vitamin C versus no study medication for six months in 42 ESKD patients on haemodialysis who required intravenous erythropoietin (dose ≥ 450 U/kg/wk). The other included study compared high-flux dialyser versus low-flux dialyser for six months in 48 haemodialysis patients who required subcutaneous erythropoietin (dose ≥ 200 U/kg/wk). Because interventions differed, data could not be combined for quantitative meta-analysis. AUTHORS' CONCLUSIONS: There was inadequate evidence identified to inform recommendation of any intervention to ameliorate ESA hyporesponsiveness. Adequately powered RCTs are required to establish the safety and efficacy of interventions to improve responsiveness to ESA therapy.


Asunto(s)
Anemia/tratamiento farmacológico , Eritropoyesis/efectos de los fármacos , Eritropoyetina/administración & dosificación , Fallo Renal Crónico/complicaciones , Diálisis Renal , Anemia/sangre , Resistencia a Medicamentos , Hematócrito , Humanos , Fallo Renal Crónico/terapia , Ensayos Clínicos Controlados Aleatorios como Asunto
18.
Appl Opt ; 52(3): 350-8, 2013 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-23338180

RESUMEN

A new method of multiplexing the speckle patterns needed in multicomponent digital shearography systems is presented. Frequency-division multiplexing (FDM) of the measurement channels is achieved by recording speckle patterns from objects illuminated by intensity-modulated sources. Each source is modulated at a discrete frequency, which is less than half of the camera frame rate, and a bank of images of the modulated speckle patterns is captured. This allows for pixel-by-pixel Fourier-based extraction of the individual speckle patterns from peaks in the power spectra. The approach is demonstrated with a two-component in-plane shearography instrument.

19.
Aust J Prim Health ; 19(1): 14-37, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-22951183

RESUMEN

With a large and increasing culturally and linguistically diverse (CALD) population, the Australian health care system faces challenges in the provision of accessible culturally competent health care. Communities at higher risk of chronic disease include CALD communities. Overseas, multicultural health workers (MHWs) have been increasingly integrated in the delivery of culturally relevant primary health care to CALD communities. The objective of this systematic review was to examine the effectiveness of MHW interventions in chronic disease prevention and self-management in CALD populations with the aim to inform policy development of effective health care in CALD communities in Australia. A systematic review protocol was developed and computerised searches were conducted of multiple electronic databases from 1 January 1995 until 1 November 2010. Thirty-nine studies were identified including 31 randomised controlled trials. Many of the studies focussed on poor and underserved ethnic minorities. Several studies reported significant improvements in participants' chronic disease prevention and self-management outcomes and meta-analyses identified a positive trend associated with MHW intervention. Australian Government policies express the need for targeted inventions for CALD communities. The broader systemic application of MHWs in Australian primary health care may provide one of the most useful targeted interventions for CALD communities.


Asunto(s)
Enfermedad Crónica/prevención & control , Competencia Cultural , Diversidad Cultural , Atención Primaria de Salud , Autocuidado , Etnicidad , Accesibilidad a los Servicios de Salud , Humanos , Lingüística , Ensayos Clínicos Controlados Aleatorios como Asunto , Poblaciones Vulnerables
20.
Dev Neurosci ; 34(1): 68-81, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22652705

RESUMEN

The major neural stem cell population in the developing cerebral cortex is the radial glia cells, which generate neurons and glial cells. The mechanisms that modulate the maintenance of the radial glia stem cell phenotype, or its differentiation, are not completely elucidated. We previously demonstrated that transforming growth factor-ß(1) (TGF-ß(1)) promotes radial glia differentiation into astrocytes in vitro [Glia 2007;55:1023-1033]. Here we investigated the intracellular signaling pathways involved in the TGF-ß(1)-induced radial glia fate commitment. We demonstrate that the mechanisms underlying the TGF-ß(1) effect on radial glia cell differentiation or progenitor potential maintenance diverge. Whereas radial glia differentiation into astrocytes is mediated by the activation of the MAPK signaling pathway, neurogenesis is modulated by different levels of PI3K and SMAD2/3 activity. Our work demonstrates that radial glia cells are a heterogeneous population and a potential target of TGF-ß(1), and suggests that its effect on radial glia fate commitment is mediated by the recruitment of a complex multipathway mechanism that controls astrocyte and neuronal generation in the developing cerebral cortex.


Asunto(s)
Astrocitos/metabolismo , Diferenciación Celular/efectos de los fármacos , Neuroglía/metabolismo , Transducción de Señal/efectos de los fármacos , Factor de Crecimiento Transformador beta1/metabolismo , Análisis de Varianza , Animales , Astrocitos/citología , Benzamidas/farmacología , Células Cultivadas , Corteza Cerebral/citología , Corteza Cerebral/crecimiento & desarrollo , Dioxoles/farmacología , Flavonoides/farmacología , Inmunohistoquímica , Ratones , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Neurogénesis/fisiología , Neuroglía/citología , Neuronas/citología , Neuronas/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/antagonistas & inhibidores , Proteína Smad2/metabolismo , Proteína smad3/metabolismo , Factor de Crecimiento Transformador beta1/farmacología
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