Brain-gut interactions in IBS

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with an estimated prevalence of 10-20%. Current understanding of the pathophysiology of IBS is incomplete due to the lack of a clearly identified pathological abnormality and due to the lack of reliable biomarkers. Possible mechanisms believed to contribute to IBS development and IBS like symptoms include physical stressors, such as infection or inflammation, psychological, and environmental factors, like anxiety, depression, and significant negative life events. Some of these mechanisms may involve the brain-gut axis (BGA). In this article we review the current knowledge on the possible involvement of the BGA in IBS and discuss new directions for potential future therapies of IBS

Are methodological quality and completeness of reporting associated with citation-based measures of publication impact? A secondary analysis of a systematic review of dementia biomarker studies

Objective: To determine whether methodological and reporting quality are associated with surrogate measures of publication impact in the field of dementia biomarker studies. Methods: We assessed dementia biomarker studies included in a previous systematic review in terms of methodological and reporting quality using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) and Standards for Reporting of Diagnostic Accuracy (STARD), respectively. We extracted additional study and journal-related data from each publication to account for factors shown to be associated with impact in previous research. We explored associations between potential determinants and measures of publication impact in univariable and stepwise multivariable linear regression analyses. Outcome measures: We aimed to collect data on four measures of publication impact: two traditional measures—average number of citations per year and 5-year impact factor of the publishing journal and two alternative measures—the Altmetric Attention Score and counts of electronic downloads. Results: The systematic review included 142 studies. Due to limited data, Altmetric Attention Scores and electronic downloads were excluded from the analysis, leaving traditional metrics as the only analysed outcome measures. We found no relationship between QUADAS and traditional metrics. Citation rates were independently associated with 5-year journal impact factor (β=0.42; p<0.001), journal subject area (β=0.39; p<0.001), number of years since publication (β=-0.29; p<0.001) and STARD (β=0.13; p<0.05). Independent determinants of 5-year journal impact factor were citation rates (β=0.45; p<0.001), statement on conflict of interest (β=0.22; p<0.01) and baseline sample size (β=0.15; p<0.05). Conclusions: Citation rates and 5-year journal impact factor appear to measure different dimensions of impact. Citation rates were weakly associated with completeness of reporting, while neither traditional metric was related to methodological rigour. Our results suggest that high publication usage and journal outlet is not a guarantee of quality and readers should critically appraise all papers regardless of presumed impact

The Effects of Arginine Deficiency on Lymphoma Cells

When L5178Y and L1210 mouse lymphosarcoma cells were incubated with rat or beef liver arginase there was up to 100% cell destruction in 24 hours. This was reversed specifically with arginine and partially with arginino-succinic acid, citrulline and ornithine. The concentration of arginine was critical; at 8 μmol/l the cells remained viable and reversible inhibition could be shown; below this level cells died. L5178Y cells were grown in medium containing from 0 to 80 μmol/l arginine for 24 hours then transferred to fresh medium for 24 hours. Viable cell counts and mitotic indices were determined, and cells were pulsed with 3H-thymidine, 3H-uridine, 14C-leucine and 14C-arginine at various times. Thymidine uptake was affected most and preceded parallel changes in viable cell numbers. It was concluded that arginine is required by these cells even in a “resting” state and despite some evidence for their capacity to utilize precursors, the tumour cells underwent rapid and extensive destruction when available arginine was severely depleted

Herbal extracts modulate the amplitude and frequency of slow waves in circular smooth muscle of mouse small intestine

Background: Herbal preparations like STW 5 (Iberogast(R)) are widely used drugs in the treatment of dyspepsia and motility-related disorders of the gastrointestinal tract. STW 5 is a phytotherapeutic agent consisting of a fixed mixture of 9 individual plant extracts. The electrophysiological mechanisms of action of STW 5 remain obscure. Aim: The aim of the present study was to investigate whether herbal extracts influence electrophysiological parameters of the small intestine. For this purpose, the resting membrane potential (RMP) and the slow wave rhythmicity of smooth muscle cells of mouse small intestine were observed. Methods: Intracellular recordings of smooth muscle cells of the circular muscle layer of mouse small intestine were performed using standard microelectrode techniques. After dissection of the mucosa, the small intestine was placed in an organ bath and a microelectrode was applied on a circular smooth muscle cell. The RMP and the amplitude of slow waves were measured in millivolts. Results: The RMP of smooth muscle cells was - 59 +/- 1.3 mV. This RMP was significantly depolarized by STW 5 ( 9.6 +/- 1.6 mV); the depolarizing effects can be mainly attributed to the constituents of matricariae flos, angelicae radix and chelidonii herba. The basal frequency of small intestinal slow waves was 39.5 +/- 1.4 min(-1) and the amplitude was 23.1 +/- 0.9 mV. STW 5 significantly reduced the amplitude and frequency of the slow waves ( 11.7 +/- 0.8 mV; 33.5 +/- 3.4 min(-1)). This effect on slow waves represents the sum of the effects of the 9 phytoextracts. Whereas angelicae radix and matricariae flos completely blocked slow wave activity, Iberis amara increased the frequency and amplitude, chelidonii herba reduced the frequency and amplitude of the slow waves, mentae piperitae folium reduced the frequency and left amplitude unchanged and liquiritae radix, carvi fructus and melissae folium had no effects. Conclusion: Herbal extracts cause changes in smooth muscle RMP and slow wave rhythmicity, up to reversible abolition, by blockade of large conductance Ca2+ channels and other not yet identified mechanisms. In herbal preparations like STW 5 these effects add up to a total effect and this study indicates that herbal preparations which are widely used in dyspepsia and motility-related disorders have characteristic, reproducible, reversible effects on small intestinal electrophysiology. Copyright (C) 2005 S. Karger AG, Basel

Soil water and available nitrogen during cover crop growth

A field trial in Ely, Cambridgeshire was set up to investigate the soil moisture and nitrogen dynamics of a frost sensitive cover crop compared to a control of an over winter stubble. Cover crops were established in late summer following wheat harvest and a summer tillage operation. Soil and aboveground biomass sampling commenced in September 2017 was continued at 2–3 week intervals until May 2018. The results highlight the fast growth of cover crops which rapidly reduced the total oxides of nitrogen present in the soil by late autumn. During winter a gradual increase in total oxides of nitrogen is measured as the cover crop residue is mineralized. The use of the frost sensitive cover crop permitted ease of management and termination, though it is not completely reliable and termination times can vary from year to year

Using frost sensitive cover crops for timely nitrogen mineralisation and soil moisture management

Cover crops can be utilised to lower soil nitrate leaching. However, depending on the species grown and cover crop termination management this may lead to nitrogen (N) immobilisation and/or depletion of soil moisture available to the following cash crop, potentially impacting on crop yields. Cover crop management is also dependent on using herbicides to terminate growth prior to planting the next crop. We used an alternative method for cover crop termination by capitalising on plant senescence by frost in a multi-species cover crop established over-winter between wheat and maize. The cover crops accumulated greater quantities of N than the control. However, upon cover crop senescence due to cold temperatures, the partially terminated cover crop significantly increased topsoil available N from December to late February. This available N in the topsoil could be susceptible to leaching although this was not observed in our study. Cover crops did not have a significant prolonged effect on soil moisture over winter and late spring. The following maize yields were not significantly different between the control and cover crop treatment. Frost sensitive cover crop species could not be reliably terminated under a temperate climate, but provided a continuous supply of soil available N as the plants senesced. Depending on the soil moisture and weather conditions in the spring there could be a N leaching risk although this could be mitigated by establishing early spring crops

Do cover crops give short term benefits for soil health?

Cover crop use in the UK is increasing with establishment often before spring cereal crops. Therefore trials were implemented to assess two different cover crop mixtures for i) their ability to remediate soil compaction, ii) aid water management and iii) increase earthworm numbers. Two cover crop mixtures; frost sensitive (black oats, oil radish and mustard) and winter hardy (forage rye, oil radish and berseem clover) were compared to control plots. This replicated trial was based at G’s Growers on an organo-mineral soil with a cover crop sown between wheat harvested in August 2016 and maize sown in May 2017. The results suggest that in the short term there are small differences in soil physical characteristics. Notably at a depth of 10–20 cm there is a reduction in soil strength as measured by the penetrologger and shear vane following the frost sensitive cover crop mix. Juvenile earthworm population was significantly greater in the control treatment compared to the frost sensitive cover crop treatment. In May 2017 maize was established across all plots

The use of cover crops in the UK: a survey

A sustainable soil management survey targeting UK arable farmers was distributed via online platforms throughout the winter of 2016–2017. The main focus of the survey was the use and management of cover crops along with tillage practice and aspects of soil health. Following harvest in 2016 two-thirds of participants used a cover crop, with 56% of those using a cover crop having 3 years or less experience. There is evidence that the species selected as a cover crop is linked to soil type whilst the benefits to soil structure is related to the extent of farmer experience. Of the participants using cover crops 81% used herbicide to terminate the cover crop. Participants provided suggestions for improvements to ecological focus area rules (based on the 2016 Basic Payment Scheme) for cover and catch crops with 70% of participants suggesting they are not suitable