Intestinal transgene delivery with native E. coli chassis allows persistent physiological changes.

Live bacterial therapeutics (LBTs) could reverse diseases by engrafting in the gut and providing persistent beneficial functions in the host. However, attempts to functionally manipulate the gut microbiome of conventionally raised (CR) hosts have been unsuccessful because engineered microbial organisms (i.e., chassis) have difficulty in colonizing the hostile luminal environment. In this proof-of-concept study, we use native bacteria as chassis for transgene delivery to impact CR host physiology. Native Escherichia coli bacteria isolated from the stool cultures of CR mice were modified to express functional genes. The reintroduction of these strains induces perpetual engraftment in the intestine. In addition, engineered native E. coli can induce functional changes that affect physiology of and reverse pathology in CR hosts months after administration. Thus, using native bacteria as chassis to "knock in" specific functions allows mechanistic studies of specific microbial activities in the microbiome of CR hosts and enables LBT with curative intent.

A Global Map of Lipid-Binding Proteins and Their Ligandability in Cells.

Lipids play central roles in physiology and disease, where their structural, metabolic, and signaling functions often arise from interactions with proteins. Here, we describe a set of lipid-based chemical proteomic probes and their global interaction map in mammalian cells. These interactions involve hundreds of proteins from diverse functional classes and frequently occur at sites of drug action. We determine the target profiles for several drugs across the lipid-interaction proteome, revealing that its ligandable content extends far beyond traditionally defined categories of druggable proteins. In further support of this finding, we describe a selective ligand for the lipid-binding protein nucleobindin-1 (NUCB1) and show that this compound perturbs the hydrolytic and oxidative metabolism of endocannabinoids in cells. The described chemical proteomic platform thus provides an integrated path to both discover and pharmacologically characterize a wide range of proteins that participate in lipid pathways in cells.

Eudicot primary cell wall glucomannan is related in synthesis, structure, and function to xyloglucan.

Hemicellulose polysaccharides influence assembly and properties of the plant primary cell wall (PCW), perhaps by interacting with cellulose to affect the deposition and bundling of cellulose fibrils. However, the functional differences between plant cell wall hemicelluloses such as glucomannan, xylan, and xyloglucan (XyG) remain unclear. As the most abundant hemicellulose, XyG is considered important in eudicot PCWs, but plants devoid of XyG show relatively mild phenotypes. We report here that a patterned ß-galactoglucomannan (ß-GGM) is widespread in eudicot PCWs and shows remarkable similarities to XyG. The sugar linkages forming the backbone and side chains of ß-GGM are analogous to those that make up XyG, and moreover, these linkages are formed by glycosyltransferases from the same CAZy families. Solid-state nuclear magnetic resonance indicated that ß-GGM shows low mobility in the cell wall, consistent with interaction with cellulose. Although Arabidopsis ß-GGM synthesis mutants show no obvious growth defects, genetic crosses between ß-GGM and XyG mutants produce exacerbated phenotypes compared with XyG mutants. These findings demonstrate a related role of these two similar but distinct classes of hemicelluloses in PCWs. This work opens avenues to study the roles of ß-GGM and XyG in PCWs.

Sphingosine 1-phosphate receptor signaling.

The sphingosine 1-phosphate (S1P) receptor signaling system is a productive model system. A hydrophobic zwitterionic lysophospholipid ligand with difficult physical properties interacts with five high-affinity G protein-coupled receptors to generate multiple downstream signals. These signals modulate homeostasis and pathology on a steep agonist concentration-response curve. Ligand presence is essential for vascular development and endothelial integrity, while acute increases in ligand concentrations result in cardiac death. Understanding this integrated biochemical system has exemplified the impact of both genetics and chemistry. Developing specific tools with defined biochemical properties for the reversible modulation of signals in real time has been essential to complement insights gained from genetic approaches that may be irreversible and compensated. Despite its knife-edge between life and death, this system, based in part on receptor subtype-selectivity and in part on differential attenuation of deleterious signals, now appears to be on the cusp of meaningful therapy for multiple sclerosis.

Real-world practice and outcomes in pilonidal surgery: Pilonidal Sinus Treatment Studying The Options (PITSTOP) cohort.

BACKGROUND: Numerous surgical approaches exist for the treatment of pilonidal disease. Current literature on treatment is of poor quality, limiting the ability to define optimal intervention. The aim of this study was to provide real-world data on current surgical practice and report patient and risk-adjusted outcomes, informing future trial design. METHODS: This UK-wide multicentre prospective cohort study, including patients (aged over 16 years) who had definitive treatment for symptomatic pilonidal disease, was conducted between May 2019 and March 2022. Patient and disease characteristics, and intervention details were analysed. Data on patient-reported outcomes, including pain, complications, treatment failure, wound issues, and quality of life, were gathered at various time points up to 6 months after surgery. Strategies were implemented to adjust for risk influencing different treatment choices and outcomes. RESULTS: Of the 667 participants consenting, 574 (86.1%) were followed up to the study end. Twelve interventions were observed. Broadly, 59.5% underwent major excisional surgery and 40.5% minimally invasive surgery. Complications occurred in 45.1% of the cohort. Those who had minimally invasive procedures had better quality of life and, after risk adjustment, less pain (score on day 1: mean difference 1.58, 95% c.i. 1.14 to 2.01), fewer complications (difference 17.5 (95% c.i. 9.1 to 25.9)%), more rapid return to normal activities (mean difference 25.9 (18.4 to 33.4) days) but a rate of higher treatment failure (difference 9.6 (95% c.i. 17.3 to 1.9)%). At study end, 25% reported an unhealed wound and 10% had not returned to normal activities. CONCLUSION: The burden after surgery for pilonidal disease is high and treatment failure is common. Minimally invasive techniques may improve outcomes at the expense of a 10% higher risk of treatment failure.

Polymorph Identification for Flexible Molecules: Linear Regression Analysis of Experimental and Calculated Solution- and Solid-State NMR Data.

The Δδ regression approach of Blade et al. [ J. Phys. Chem. A 2020, 124(43), 8959-8977] for accurately discriminating between solid forms using a combination of experimental solution- and solid-state NMR data with density functional theory (DFT) calculation is here extended to molecules with multiple conformational degrees of freedom, using furosemide polymorphs as an exemplar. As before, the differences in measured 1H and 13C chemical shifts between solution-state NMR and solid-state magic-angle spinning (MAS) NMR (Δδexperimental) are compared to those determined by gauge-including projector augmented wave (GIPAW) calculations (Δδcalculated) by regression analysis and a t-test, allowing the correct furosemide polymorph to be precisely identified. Monte Carlo random sampling is used to calculate solution-state NMR chemical shifts, reducing computation times by avoiding the need to systematically sample the multidimensional conformational landscape that furosemide occupies in solution. The solvent conditions should be chosen to match the molecule's charge state between the solution and solid states. The Δδ regression approach indicates whether or not correlations between Δδexperimental and Δδcalculated are statistically significant; the approach is differently sensitive to the popular root mean squared error (RMSE) method, being shown to exhibit a much greater dynamic range. An alternative method for estimating solution-state NMR chemical shifts by approximating the measured solution-state dynamic 3D behavior with an ensemble of 54 furosemide crystal structures (polymorphs and cocrystals) from the Cambridge Structural Database (CSD) was also successful in this case, suggesting new avenues for this method that may overcome its current dependency on the prior determination of solution dynamic 3D structures.

Classification and stratification in pilonidal sinus disease: findings from the PITSTOP cohort.

AIM: Research in pilonidal disease faces several challenges, one of which is consistent and useful disease classification. The International Pilonidal Society (IPS) proposed a four-part classification in 2017. The aim of this work was to assess the validity and reliability of this tool using data from the PITSTOP cohort study. METHOD: Face validity was assessed by mapping the items/domains in the IPS tool against tools identified through a systematic review. Key concepts were defined as those appearing in more than two-thirds of published tools. Concurrent and predictive validity were assessed by comparing key patient-reported outcome measures between groups at baseline and at clinic visit. The outcomes of interest were health utility, Cardiff Wound Impact Questionnaire (CWIQ) and pain score between groups. Significance was set at p = 0.05 a priori. Interrater reliability was assessed using images captured during the PITSTOP cohort. Ninety images were assessed by six raters (two experts, two general surgeons and two trainees), and classified into IPS type. Interrater reliability was assessed using the unweighted kappa and unweighted Gwet's AC1 statistics. RESULTS: For face validity items represented in the IPS were common to other classification systems. Concurrent and predictive validity assessment showed differences in health utility and pain between groups at baseline, and for some treatment groups at follow-up. Assessors agreed the same classification in 38% of participants [chance-corrected kappa 0.52 (95% CI 0.42-0.61), Gwet's AC1 0.63 (95% CI 0.56-0.69)]. CONCLUSION: The IPS classification demonstrates key aspects of reliability and validity that would support its implementation.

Research and practice priorities in pilonidal sinus disease: a consensus from the PITSTOP study.

AIM: Pilonidal sinus disease is a common condition treated by colorectal surgeons. There is a lack of literature in the field to guide optimal management of this condition. As part of the PITSTOP study, we aimed to identify policy and research priorities to provide direction to the field. METHOD: Patients and surgeons were invited to participate. A 'So what, now what' exercise was conducted, informed by data from PITSTOP. This generated statements for research and practice priorities. A three-round online Delphi study was conducted, ranking statements based on policy and research separately. Statements were rated 1 (not important) to 9 (important). Statements that were rated 7-9 by more than 70% of participants were entered into the consensus meeting. Personalized voting feedback was shown between rounds. A face-to-face meeting was held to discuss statements, and participants were asked to rank statements using a weighted choice vote. RESULTS: Twenty-two people participated in the focus group, generating 14 research and 19 policy statements. Statements were voted on by 56 participants in round 1, 53 in round 2 and 51 in round 3. A total of 15 policy statements and 19 research statements were discussed in the consensus round. Key policy statements addressed treatment strategies and intensity, surgeon training opportunities, need for classification and the impact of treatment on return to work. Research recommendations included design of future trials, methodology considerations and research questions. CONCLUSION: This study has identified research and policy priorities in pilonidal sinus disease which are relevant to patients and clinicians. These should inform practice and future research.

Early development of local data dashboards to depict the substance use care cascade for youth involved in the legal system: qualitative findings from end users.

INTRODUCTION: Rates of substance use are high among youth involved in the legal system (YILS); however, YILS are less likely to initiate and complete substance use treatment compared to their non legally-involved peers. There are multiple steps involved in connecting youth to needed services, from screening and referral within the juvenile legal system to treatment initiation and completion within the behavioral health system. Understanding potential gaps in the care continuum requires data and decision-making from these two systems. The current study reports on the development of data dashboards that integrate these systems' data to help guide decisions to improve substance use screening and treatment for YILS, focusing on end-user feedback regarding dashboard utility. METHODS: Three focus groups were conducted with n = 21 end-users from juvenile legal systems and community mental health centers in front-line positions and in decision-making roles across 8 counties to gather feedback on an early version of the data dashboards; dashboards were then modified based on feedback. RESULTS: Qualitative analysis revealed topics related to (1) important aesthetic features of the dashboard, (2) user features such as filtering options and benchmarking to compare local data with other counties, and (3) the centrality of consistent terminology for data dashboard elements. Results also revealed the use of dashboards to facilitate collaboration between legal and behavioral health systems. CONCLUSIONS: Feedback from end-users highlight important design elements and dashboard utility as well as the challenges of working with cross-system and cross-jurisdiction data.

Volatile chemical product emissions enhance ozone and modulate urban chemistry.

Decades of air quality improvements have substantially reduced the motor vehicle emissions of volatile organic compounds (VOCs). Today, volatile chemical products (VCPs) are responsible for half of the petrochemical VOCs emitted in major urban areas. We show that VCP emissions are ubiquitous in US and European cities and scale with population density. We report significant VCP emissions for New York City (NYC), including a monoterpene flux of 14.7 to 24.4 kg ⋅ d-1 ⋅ km-2 from fragranced VCPs and other anthropogenic sources, which is comparable to that of a summertime forest. Photochemical modeling of an extreme heat event, with ozone well in excess of US standards, illustrates the significant impact of VCPs on air quality. In the most populated regions of NYC, ozone was sensitive to anthropogenic VOCs (AVOCs), even in the presence of biogenic sources. Within this VOC-sensitive regime, AVOCs contributed upwards of ∼20 ppb to maximum 8-h average ozone. VCPs accounted for more than 50% of this total AVOC contribution. Emissions from fragranced VCPs, including personal care and cleaning products, account for at least 50% of the ozone attributed to VCPs. We show that model simulations of ozone depend foremost on the magnitude of VCP emissions and that the addition of oxygenated VCP chemistry impacts simulations of key atmospheric oxidation products. NYC is a case study for developed megacities, and the impacts of VCPs on local ozone are likely similar for other major urban regions across North America or Europe.

Large contribution of biomass burning emissions to ozone throughout the global remote troposphere.

Ozone is the third most important anthropogenic greenhouse gas after carbon dioxide and methane but has a larger uncertainty in its radiative forcing, in part because of uncertainty in the source characteristics of ozone precursors, nitrogen oxides, and volatile organic carbon that directly affect ozone formation chemistry. Tropospheric ozone also negatively affects human and ecosystem health. Biomass burning (BB) and urban emissions are significant but uncertain sources of ozone precursors. Here, we report global-scale, in situ airborne measurements of ozone and precursor source tracers from the NASA Atmospheric Tomography mission. Measurements from the remote troposphere showed that tropospheric ozone is regularly enhanced above background in polluted air masses in all regions of the globe. Ozone enhancements in air with high BB and urban emission tracers (2.1 to 23.8 ppbv [parts per billion by volume]) were generally similar to those in BB-influenced air (2.2 to 21.0 ppbv) but larger than those in urban-influenced air (-7.7 to 6.9 ppbv). Ozone attributed to BB was 2 to 10 times higher than that from urban sources in the Southern Hemisphere and the tropical Atlantic and roughly equal to that from urban sources in the Northern Hemisphere and the tropical Pacific. Three independent global chemical transport models systematically underpredict the observed influence of BB on tropospheric ozone. Potential reasons include uncertainties in modeled BB injection heights and emission inventories, export efficiency of BB emissions to the free troposphere, and chemical mechanisms of ozone production in smoke. Accurately accounting for intermittent but large and widespread BB emissions is required to understand the global tropospheric ozone burden.

Exploring the Potential of Multinuclear Solid-State 1 H, 13 C, and 35 Cl Magnetic Resonance To Characterize Static and Dynamic Disorder in Pharmaceutical Hydrochlorides.

Crystallographic disorder, whether static or dynamic, can be detrimental to the physical and chemical stability, ease of crystallization and dissolution rate of an active pharmaceutical ingredient. Disorder can result in a loss of manufacturing control leading to batch-to-batch variability and can lengthen the process of structural characterization. The range of NMR active nuclei makes solid-state NMR a unique technique for gaining nucleus-specific information about crystallographic disorder. Here, we explore the use of high-field 35 Cl solid-state NMR at 23.5 T to characterize both static and dynamic crystallographic disorder: specifically, dynamic disorder occurring in duloxetine hydrochloride (1), static disorder in promethazine hydrochloride (2), and trifluoperazine dihydrochloride (3). In all structures, the presence of crystallographic disorder was confirmed by 13 C cross-polarization magic-angle spinning (CPMAS) NMR and supported by GIPAW-DFT calculations, and in the case of 3, 1 H solid-state NMR provided additional confirmation. Applying 35 Cl solid-state NMR to these compounds, we show that higher magnetic fields are beneficial for resolving the crystallographic disorder in 1 and 3, while broad spectral features were observed in 2 even at higher fields. Combining the data obtained from 1 H, 13 C, and 35 Cl NMR, we show that 3 exhibits a unique case of disorder involving the + N-H hydrogen positions of the piperazinium ring, driving the chloride anions to occupy three distinct sites.

Influence of Wildfire on Urban Ozone: An Observationally Constrained Box Modeling Study at a Site in the Colorado Front Range.

Increasing trends in biomass burning emissions significantly impact air quality in North America. Enhanced mixing ratios of ozone (O3) in urban areas during smoke-impacted periods occur through transport of O3 produced within the smoke or through mixing of pyrogenic volatile organic compounds (PVOCs) with urban nitrogen oxides (NOx = NO + NO2) to enhance local O3 production. Here, we analyze a set of detailed chemical measurements, including carbon monoxide (CO), NOx, and speciated volatile organic compounds (VOCs), to evaluate the effects of smoke transported from relatively local and long-range fires on O3 measured at a site in Boulder, Colorado, during summer 2020. Relative to the smoke-free period, CO, background O3, OH reactivity, and total VOCs increased during both the local and long-range smoke periods, but NOx mixing ratios remained approximately constant. These observations are consistent with transport of PVOCs (comprised primarily of oxygenates) but not NOx with the smoke and with the influence of O3 produced within the smoke upwind of the urban area. Box-model calculations show that local O3 production during all three periods was in the NOx-sensitive regime. Consequently, this locally produced O3 was similar in all three periods and was relatively insensitive to the increase in PVOCs. However, calculated NOx sensitivities show that PVOCs substantially increase O3 production in the transition and NOx-saturated (VOC-sensitive) regimes. These results suggest that (1) O3 produced during smoke transport is the main driver for O3 increases in NOx-sensitive urban areas and (2) smoke may cause an additional increase in local O3 production in NOx-saturated (VOC-sensitive) urban areas. Additional detailed VOC and NOx measurements in smoke impacted urban areas are necessary to broadly quantify the effects of wildfire smoke on urban O3 and develop effective mitigation strategies.

Midlatitude Ozone Depletion and Air Quality Impacts from Industrial Halogen Emissions in the Great Salt Lake Basin.

We report aircraft observations of extreme levels of HCl and the dihalogens Cl2, Br2, and BrCl in an industrial plume near the Great Salt Lake, Utah. Complete depletion of O3 was observed concurrently with halogen enhancements as a direct result of photochemically produced halogen radicals. Observed fluxes for Cl2, HCl, and NOx agreed with facility-reported emissions inventories. Bromine emissions are not required to be reported in the inventory, but are estimated as 173 Mg year-1 Br2 and 949 Mg year-1 BrCl, representing a major uncounted oxidant source. A zero-dimensional photochemical box model reproduced the observed O3 depletions and demonstrated that bromine radical cycling was principally responsible for the rapid O3 depletion. Inclusion of observed halogen emissions in both the box model and a 3D chemical model showed significant increases in oxidants and particulate matter (PM2.5) in the populated regions of the Great Salt Lake Basin, where winter PM2.5 is among the most severe air quality issues in the U.S. The model shows regional PM2.5 increases of 10%-25% attributable to this single industrial halogen source, demonstrating the impact of underreported industrial bromine emissions on oxidation sources and air quality within a major urban area of the western U.S.

A survey of treatment preferences of UK surgeons in the treatment of pilonidal sinus disease.

AIM: Pilonidal sinus is a common surgical condition which impacts a young and economically active population. There are limited data to guide treatment in this condition. The aim of this work was to assess current practice. METHOD: A survey was developed as part of the PITSTOP study. It included questions on volume of practice, treatment preferences and training. The survey was delivered to consultant surgeons with a UK practice through social media, specialty surgical societies and through PITSTOP sites. Descriptive statistics were reported. RESULTS: Of the 200 people who received a link to the questionnaire, 109 completed it (response rate 54.5%). Respondents treated a median of 15 patients per year, with 20% of these having recurrent disease. Estimates of recurrence were higher than reported in the literature and higher than in a survey 10 years ago. Nearly 50% of surgeons advocate nonsurgical treatment in some patients despite limited evidence. Two thirds practised interventions not favoured by guidelines, including excision and leave open and midline closure techniques. Invasive procedures tended to be favoured when minimally invasive procedures may be appropriate. Surgical training programmes were the key training setting for commonly offered procedures, with few other training opportunities reported. For some procedures, no formal training had been given. CONCLUSION: This survey highlights issues with quality in pilonidal surgery in the UK, with persistence of potentially outdated techniques, no consistent treatment escalation plan, a suggestion of under- or overtreatment of disease and a high perception of failure. This may relate to the current system of training and lack of evidence-based guidance.

Is early bowel resection better than medical therapy for ileocolonic Crohn's disease? A systematic review and meta-analysis.

AIM: There is emerging evidence supporting early bowel resection (EBR) for ileocaecal Crohn's disease (CD) as an alternative to conventional escalation of medical therapy (MT). Here, we present a systematic review and meta-analysis of studies comparing the outcomes of EBR with those of MT in ileocolonic CD, with a focus on ileocaecal disease. METHODOLOGY: The MEDLINE, Embase, CINAHL and Cochrane Central Register of Controlled Trials databases were searched for studies reporting the outcomes of EBR versus MT for ileocolonic CD. The Cochrane tools for assessment of risk of bias were used to assess the methodological quality of studies. RESULTS: Nine records (from 8 studies, with a total of 1867 patients) were included in the analysis. Six studies were observational and two were randomised controlled trials. There was a reduced need for drug therapy in the EBR arm. The rate of intestinal resection at 5 years was 7.8% in the EBR arm and 25.4% in the MT group with a pooled OR of 0.32 (95% CI 0.19, 0.54; p < 0.0001). The EBR group had a longer resection-free survival (HR 0.56, 95% CI 0.38, 0.83; p = 0.004). These outcomes were consistent in a subgroup analysis of patients with ileocaecal disease. Morbidity and quality of life scores were similar across the two groups. CONCLUSION: EBR is associated with a more stable remission compared to initial MT for ileocolonic Crohn's disease. There is enough evidence to support EBR as an alternative to escalation of MT in selected patients with limited ileocaecal disease.

Patient preferences for pilonidal sinus treatments: a discrete choice experiment survey.

BACKGROUND: A range of treatments are available for pilonidal sinus disease (PSD), each of which has a different risk/benefit profile. The aim of this study was to collect patient views on which interventions they would rather avoid and which outcomes they most value for PSD. METHOD: We conducted an online survey using the discrete choice experiment (DCE) method. DCE task involved participants choosing the best treatment option when presented with a set of competing hypothetical treatment profiles. Participants with symptomatic PSD, referred for elective surgery were recruited from 33 NHS trusts between 2020 and 2022. Collected DCE data were analysed using regression analyses. RESULTS: One hundred and eleven participants completed the survey. In the overall group, low risk of infection/persistence was the most important characteristic when making a treatment decision (attribute importance score of 70%), followed by treatments with shorter recovery time with an attribute importance score of 30%. The results demonstrated that patients are willing to accept trade-offs between treatment recovery time and risk of infection/persistence. Patients above 30 years old are willing to accept a higher chance of treatment failure in exchange for rapid treatment recovery (risk tolerance between 22.35 - 34.67 percentage points). Conversely, patients in the younger age groups, were risk averse, and were only willing to accept a small risk 1.51-2.15 in exchange for a treatment with faster recovery time. All patient groups appear to the reject the excision and leave open technique due to the need for protracted nursing care. CONCLUSION: This study highlights the need for shared decision making when it comes to surgery for PSD.

Surgeon preference for treatment allocation in older people facing major gastrointestinal surgery: an application of the discrete choice experiment methodology.

AIM: Variation in major gastrointestinal surgery rates in the older population suggests heterogeneity in surgical management. A higher prevalence of comorbidities, frailty and cognitive impairments in the older population may account for some variation. The aim of this study was to determine surgeon preference for major surgery versus conservative management in hypothetical patient scenarios based on key attributes. METHOD: A survey was designed according to the discrete choice methodology guided by a separate qualitative study. Questions were designed to test for associations between key attributes (age, comorbidity, urgency of presentation, pathology, functional and cognitive status) and treatment preference for major gastrointestinal surgery versus conservative management. The survey consisting of 18 hypothetical scenarios was disseminated electronically to UK gastrointestinal surgeons. Binomial logistic regression was used to identify associations between the attributes and treatment preference. RESULTS: In total, 103 responses were received after 256 visits to the questionnaire site (response rate 40.2%). Participants answered 1847 out of the 1854 scenarios (99.6%). There was a preference for major surgery in 1112/1847 (60.2%) of all scenarios. Severe comorbidities (OR 0.001, 95% CI 0.000-0.030; P = 0.000), severe cognitive impairment (OR 0.001, 95% CI 0.000-0.033; P = 0.000) and age 85 years and above (OR 0.028, 95% CI 0.005-0.168; P = 0.000) were all significant in the decision not to offer major gastrointestinal surgery. CONCLUSION: This study has demonstrated variation in surgical treatment preference according to key attributes in hypothetical scenarios. The development of fitness-stratified guidelines may help to reduce variation in surgical practice in the older population.

The Association of Coloproctology of Great Britain and Ireland guideline on the management of anal fissure.

AIM: The management of anal fissure: ACPGBI position statement was written 15 years ago. [KLR Cross et al., Colorectal Dis, 2008]. Our aim was to update the guideline and provide recommendations on the most effective treatment for patients with anal fissures utilising a multidisciplinary, rigorous guideline methodology. METHODS: The development process consisted of six phases. In phase 1 we defined the scope of the guideline. The patient population included patients with acute and chronic anal fissure. The target group was all practitioners (primary and secondary care) treating patients with fissures and, in addition, healthcare workers and patients who desired information regarding fissure management. In phase 2 we formed a guideline development group (GDG) including a methodologist. In phase 3 review questions were formulated, using a reversed PICO process, starting with possible recommendations based on the GDG's knowledge. In phase 4 a comprehensive literature search focused on existing systematic reviews addressing each review question, supplemented by more recent studies if appropriate. In phase 5 data were extracted from the included papers and checked by the GDG. If indicated, meta-analysis of systematic review data was updated by the GDG. During phase 6 the GDG members decided what recommendations could be made based on the evidence in the literature and strength of the recommendation was assessed using 'grade'. RESULTS: This guideline is divided into two sections: Primary care which includes (i) diagnosis; (ii) basic treatment; (iii) topical treatment; and secondary care which includes (iv) botulinum toxin therapy; (v) surgical intervention and (vi) special situations (including pregnancy and breast-feeding patients, children, receptive anal intercourse and low-pressure fissures). A total of 23 recommendations were formulated. A new term clinically healed was described by the GDG. CONCLUSION: This guideline provides an up-to-date evidence-based summary of the current knowledge of the management of anal fissure and may serve as a useful guide for clinicians as well as a potential reference for patients.

Nuclear spin diffusion under fast magic-angle spinning in solid-state NMR.

Solid-state nuclear spin diffusion is the coherent and reversible process through which spin order is transferred via dipolar couplings. With the recent increases in magic-angle spinning (MAS) frequencies and magnetic fields becoming routinely applied in solid-state nuclear magnetic resonance, understanding how the increased 1H resolution obtained affects spin diffusion is necessary for interpretation of several common experiments. To investigate the coherent contributions to spin diffusion with fast MAS, we have developed a low-order correlation in Liouville space model based on the work of Dumez et al. (J. Chem. Phys. 33, 224501, 2010). Specifically, we introduce a new method for basis set selection, which accounts for the resonance-offset dependence at fast MAS. Furthermore, we consider the necessity of including chemical shift, both isotropic and anisotropic, in the modeling of spin diffusion. Using this model, we explore how different experimental factors change the nature of spin diffusion. Then, we show case studies to exemplify the issues that arise in using spin diffusion techniques at fast spinning. We show that the efficiency of polarization transfer via spin diffusion occurring within a deuterated and 100% back-exchanged protein sample at 60 kHz MAS is almost entirely dependent on resonance offset. We additionally identify temperature-dependent magnetization transfer in beta-aspartyl L-alanine, which could be explained by the influence of an incoherent relaxation-based nuclear Overhauser effect.