455 research outputs found
Environmental Factors in the Relapse and Recurrence of Inflammatory Bowel Disease:A Review of the Literature
The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability
Photo-antagonism of the GABAA receptor
Neurotransmitter receptor trafficking is fundamentally important for synaptic transmission and neural network activity. GABAA receptors and inhibitory synapses are vital components of brain function, yet much of our knowledge regarding receptor mobility and function at inhibitory synapses is derived indirectly from using recombinant receptors, antibody-tagged native receptors and pharmacological treatments. Here we describe the use of a set of research tools that can irreversibly bind to and affect the function of recombinant and neuronal GABAA receptors following ultraviolet photoactivation. These compounds are based on the competitive antagonist gabazine and incorporate a variety of photoactive groups. By using site-directed mutagenesis and ligand-docking studies, they reveal new areas of the GABA binding site at the interface between receptor β and α subunits. These compounds enable the selected inactivation of native GABAA receptor populations providing new insight into the function of inhibitory synapses and extrasynaptic receptors in controlling neuronal excitation
Comparison of two independent systematic reviews of trials of recombinant human bone morphogenetic protein-2 (rhBMP-2) : The Yale Open Data Access Medtronic Project
Background: It is uncertain whether the replication of systematic reviews, particularly those with the same objectives and resources, would employ similar methods and/or arrive at identical findings. We compared the results and conclusions of two concurrent systematic reviews undertaken by two independent research teams provided with the same objectives, resources, and individual participant-level data. Methods: Two centers in the USA and UK were each provided with participant-level data on 17 multi-site clinical trials of recombinant human bone morphogenetic protein-2 (rhBMP-2). The teams were blinded to each other's methods and findings until after publication. We conducted a retrospective structured comparison of the results of the two systematic reviews. The main outcome measures included (1) trial inclusion criteria; (2) statistical methods; (3) summary efficacy and risk estimates; and (4) conclusions. Results: The two research teams' meta-analyses inclusion criteria were broadly similar but differed slightly in trial inclusion and research methodology. They obtained similar results in summary estimates of most clinical outcomes and adverse events. Center A incorporated all trials into summary estimates of efficacy and harms, while Center B concentrated on analyses stratified by surgical approach. Center A found a statistically significant, but small, benefit whereas Center B reported no advantage. In the analysis of harms, neither showed an increased cancer risk at 48 months, although Center B reported a significant increase at 24 months. Conclusions reflected these differences in summary estimates of benefit balanced with small but potentially important risk of harm. Conclusions: Two independent groups given the same research objectives, data, resources, funding, and time produced broad general agreement but differed in several areas. These differences, the importance of which is debatable, indicate the value of the availability of data to allow for more than a single approach and a single interpretation of the data. Systematic review registration: PROSPERO CRD42012002040and CRD42012001907
Coffee resistance to the main diseases : leaf rust and coffee berry disease
Sucesso considerável tem sido obtido no uso do melhoramento clássico para o controle de doenças de plantas economicamente importantes, tais como a ferrugem alaranjada das folhas e a antracnose dos frutos do cafeeiro (CBD). Há um grande consenso de que o uso de plantas geneticamente resistentes é o meio mais apropriado e eficaz em termos de custos do controle das doenças das plantas, sendo também um dos elementos chave do melhoramento da produção agrícola. Tem sido também reconhecido que um melhor conhecimento do agente patogênico e dos mecanismos de defesa das plantas permitirá o desenvolvimento de novas abordagens no sentido de aumentar a durabilidade da resistência. Após uma breve descrição de conceitos na área da resistência das plantas às doenças, nesta revisão tentou-se dar uma idéia do progresso na investigação da ferrugem alaranjada do cafeeiro e do CBD relativamente ao processo de infecção e variabilidade dos agentes patogênicos, melhoramento do cafeeiro para a resistência e mecanismos de resistência do cafeeiro
Recommended from our members
Respective impacts of Arctic sea ice decline and increasing greenhouse gases concentration on Sahel precipitation
The impact of climate change on Sahel precipitation is uncertain and has to be widely documented. Recently, it has been shown that Arctic sea ice loss leverages the global warming effects worldwide, suggesting a potential impact of Arctic sea ice decline on tropical regions. However, defining the specific roles of increasing greenhouse gases (GHG) concentration and declining Arctic sea ice extent on Sahel climate is not straightforward since the former impacts the latter. We avoid this dependency by analysing idealized experiments performed with the CNRM-CM5 coupled model. Results show that the increase in GHG concentration explains most of the Sahel precipitation change. We found that the impact due to Arctic sea ice loss depends on the level of atmospheric GHG concentration. When the GHG concentration is relatively low (values representative of 1980s), then the impact is moderate over the Sahel. However, when the concentration in GHG is levelled up, then Arctic sea ice loss leads to increased Sahel precipitation. In this particular case the ocean-land meridional gradient of temperature strengthens, allowing a more intense monsoon circulation. We linked the non-linearity of Arctic sea ice decline impact with differences in temperature and sea level pressure changes over the North Atlantic Ocean. We argue that the impact of the Arctic sea ice loss will become more relevant with time, in the context of climate change
A randomised, double-blind, placebo-controlled trial of repeated nebulisation of non-viral cystic fibrosis transmembrane conductance regulator (CFTR) gene therapy in patients with cystic fibrosis
BACKGROUND: Cystic fibrosis (CF) is a chronic, life-limiting disease caused by mutations in the CF
transmembrane conductance regulator (CFTR) gene leading to abnormal airway surface ion transport,
chronic lung infections, inflammation and eventual respiratory failure. With the exception of the
small-molecule potentiator, ivacaftor (Kalydeco®, Vertex Pharmaceuticals, Boston, MA, USA), which is
suitable for a small proportion of patients, there are no licensed therapies targeting the basic defect.
The UK Cystic Fibrosis Gene Therapy Consortium has taken a cationic lipid-mediated CFTR gene therapy
formulation through preclinical and clinical development.
OBJECTIVE: To determine clinical efficacy of the formulation delivered to the airways over a period of
1 year in patients with CF.
DESIGN: This was a randomised, double-blind, placebo-controlled Phase IIb trial of the CFTR gene–liposome
complex pGM169/GL67A. Randomisation was performed via InForm™ version 4.6 (Phase Forward
Incorporated, Oracle, CA, USA) and was 1 : 1, except for patients in the mechanistic subgroups (2 : 1).
Allocation was blinded by masking nebuliser chambers.
SETTINGS: Data were collected in the clinical and scientific sites and entered onto a trial-specific InForm,
version 4.6 database.
PARTICIPANTS: Patients with CF aged ≥ 12 years with forced expiratory volume in the first second (FEV1)
between 50% and 90% predicted and any combination of CFTR mutations. The per-protocol group
(≥ 9 doses) consisted of 54 patients receiving placebo (62 randomised) and 62 patients receiving gene
therapy (78 randomised).
INTERVENTIONS: Subjects received 5 ml of nebulised pGM169/G67A (active) or 0.9% saline (placebo) at
28 (±5)-day intervals over 1 year.
MAIN OUTCOME MEASURES: The primary end point was the relative change in percentage predicted FEV1
over the 12-month period. A number of secondary clinical outcomes were assessed alongside safety
measures: other spirometric values; lung clearance index (LCI) assessed by multibreath washout; structural
disease on computed tomography (CT) scan; the Cystic Fibrosis Questionnaire – Revised (CFQ-R), a
validated quality-of-life questionnaire; exercise capacity and monitoring; systemic and sputum inflammatory
markers; and adverse events (AEs). A mechanistic study was performed in a subgroup in whom transgene
deoxyribonucleic acid (DNA) and messenger ribonucleic acid (mRNA) was measured alongside nasal and
lower airway potential difference.
RESULTS: There was a significant (p = 0.046) treatment effect (TE) of 3.7% [95% confidence interval (CI)
0.1% to 7.3%] in the primary end point at 12 months and in secondary end points, including forced vital
capacity (FVC) (p = 0.031) and CT gas trapping (p = 0.048). Other outcomes, although not reaching
statistical significance, favoured active treatment. Effects were noted by 1 month and were irrespective
of sex, age or CFTR mutation class. Subjects with a more severe baseline FEV1 had a FEV1 TE of 6.4%
(95% CI 0.8% to 12.1%) and greater changes in many other secondary outcomes. However, the more
mildly affected group also demonstrated benefits, particularly in small airway disease markers such as LCI.
The active group showed a significantly (p = 0.032) greater bronchial chloride secretory response. No
difference in treatment-attributable AEs was seen between the placebo and active groups.
CONCLUSIONS: Monthly application of the pGM169/GL67A gene therapy formulation was associated with
an improvement in lung function, other clinically relevant parameters and bronchial CFTR function,
compared with placebo.
LIMITATIONS: Although encouraging, the improvement in FEV1 was modest and was not accompanied by
detectable improvement in patients’ quality of life.
FUTURE WORK: Future work will focus on attempts to increase efficacy by increasing dose or frequency,
the coadministration of a CFTR potentiator, or the use of modified viral vectors capable of
repeated administration.
TRIAL REGISTRATION: ClinicalTrials.gov NCT01621867
The chemical signatures underlying host plant discrimination by aphids
The diversity of phytophagous insects is largely attributable to speciation involving shifts between host plants. These shifts are mediated by the close interaction between insects and plant metabolites. However, there has been limited progress in understanding the chemical signatures that underlie host preferences. We use the pea aphid (Acyrthosiphon pisum) to address this problem. Host-associated races of pea aphid discriminate between plant species in race-specific ways. We combined metabolomic profiling of multiple plant species with behavioural tests on two A. pisum races, to identify metabolites that explain variation in either acceptance or discrimination. Candidate compounds were identified using tandem mass spectrometry. Our results reveal a small number of compounds that explain a large proportion of variation in the differential acceptability of plants to A. pisum races. Two of these were identified as L-phenylalanine and L-tyrosine but it may be that metabolically-related compounds directly influence insect behaviour. The compounds implicated in differential acceptability were not related to the set correlated with general acceptability of plants to aphids, regardless of host race. Small changes in response to common metabolites may underlie host shifts. This study opens new opportunities for understanding the mechanistic basis of host discrimination and host shifts in insects
The Physical Attributes Most Required in Professional Ballet: A Delphi Study
Background It is commonly accepted that dancers are undoubtedly athletes, with ballet perhaps the most demanding
dance form. No previous study has sought to define the physical attributes most desired for classical ballet by professional
companies and vocational schools. These are likely to include
both aesthetic features and attributes that reduce the risk of
injury as well as enhance performance.
Method An initial survey question using the modified Delphi
technique was sent using Opinio Survey Software to a selected
international expert panel. This was drawn both from those
involved in selection of elite professional ballet dancers, and
the international medical professionals involved in the care of
dancers. The first questionnaire was open-ended to scope for
all the physical attributes most favoured by the professional
experts.
Results There were 148 responses from the panel of international experts. In total 34 physical attributes were suggested.
The 2 most recommended physical criteria for selection into
the profession were overall flexibility and overall strength.
These results are discussed in the context of the published literature on the mechanics, anatomy and physiology of ballet.
Conclusion Flexibility and strength are the 2 features most
sought after in elite ballet dancers
The role of peptides in bone healing and regeneration: A systematic review
Background: Bone tissue engineering and the research surrounding peptides has expanded significantly over the last few decades. Several peptides have been shown to support and stimulate the bone healing response and have been proposed as therapeutic vehicles for clinical use. The aim of this comprehensive review is to present the clinical and experimental studies analysing the potential role of peptides for bone healing and bone regeneration. Methods: A systematic review according to PRISMA guidelines was conducted. Articles presenting peptides capable of exerting an upregulatory effect on osteoprogenitor cells and bone healing were included in the study. Results: Based on the available literature, a significant amount of experimental in vitro and in vivo evidence exists. Several peptides were found to upregulate the bone healing response in experimental models and could act as potential candidates for future clinical applications. However, from the available peptides that reached the level of clinical trials, the presented results are limited. Conclusion: Further research is desirable to shed more light into the processes governing the osteoprogenitor cellular responses. With further advances in the field of biomimetic materials and scaffolds, new treatment modalities for bone repair will emerge
Short-Lived Trace Gases in the Surface Ocean and the Atmosphere
The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Here we review these exchanges and their importance for a range of gases whose lifetimes are generally short compared to the main greenhouse gases and which are, in most cases, more reactive than them. Gases considered include sulphur and related compounds, organohalogens, non-methane hydrocarbons, ozone, ammonia and related compounds, hydrogen and carbon monoxide. Finally, we stress the interactivity of the system, the importance of process understanding for modeling, the need for more extensive field measurements and their better seasonal coverage, the importance of inter-calibration exercises and finally the need to show the importance of air-sea exchanges for global cycling and how the field fits into the broader context of Earth System Science
- …
