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.

Elevated CO2 has concurrent effects on leaf and grain metabolism but minimal effects on yield in wheat.

While the general effect of CO2 enrichment on photosynthesis, stomatal conductance, N content, and yield has been documented, there is still some uncertainty as to whether there are interactive effects between CO2 enrichment and other factors, such as temperature, geographical location, water availability, and cultivar. In addition, the metabolic coordination between leaves and grains, which is crucial for crop responsiveness to elevated CO2, has never been examined closely. Here, we address these two aspects by multi-level analyses of data from several free-air CO2 enrichment experiments conducted in five different countries. There was little effect of elevated CO2 on yield (except in the USA), likely due to photosynthetic capacity acclimation, as reflected by protein profiles. In addition, there was a significant decrease in leaf amino acids (threonine) and macroelements (e.g. K) at elevated CO2, while other elements, such as Mg or S, increased. Despite the non-significant effect of CO2 enrichment on yield, grains appeared to be significantly depleted in N (as expected), but also in threonine, the S-containing amino acid methionine, and Mg. Overall, our results suggest a strong detrimental effect of CO2 enrichment on nutrient availability and remobilization from leaves to grains.

Premier League academy soccer players' experiences of competing in a tournament bio-banded for biological maturation.

Individual differences in the growth and maturation have been shown to impact player performance and development in youth soccer. This study investigated Premier League academy players' experiences of participating in a tournament bio-banded for biological maturation. Players (N = 66) from four professional soccer clubs aged 11 and 14 years and between 85-90% of adult stature participated in a tournament. Players competed in three 11 vs 11 games on a full size pitch with 25-min halves. Sixteen players participated in four 15-min focus groups and were asked to describe their experiences of participating in the bio-banded tournament in comparison to age group competition. All players described their experience as positive and recommended the Premier League integrate bio-banding into the existing games programme. In comparison to age-group competitions, early maturing players described the bio-banded games more physically challenging, and found that they had to adapt their style of play placing a greater emphasis on technique and tactics. Late maturing players considered the games to be less physically challenging, yet appreciated the having more opportunity to use, develop and demonstrate their technical, physical, and psychological competencies. Bio-banding strategies appear to contribute positively towards the holistic development of young soccer players.

Evidence for divergence of response in Indica, Japonica, and wild rice to high CO2 × temperature interaction.

High CO2 and high temperature have an antagonistic interaction effect on rice yield potential and present a unique challenge to adapting rice to projected future climates. Understanding how the differences in response to these two abiotic variables are partitioned across rice germplasm accessions may be key to identifying potentially useful sources of resilient alleles for adapting rice to climate change. In this study, we evaluated eleven globally diverse rice accessions under controlled conditions at two carbon dioxide concentrations (400 and 600 ppm) and four temperature environments (29 °C day/21 °C night; 29 °C day/21 °C night with additional heat stress at anthesis; 34 °C day/26 °C night; and 34 °C day/26 °C night with additional heat stress at anthesis) for a suite of traits including five yield components, five growth characteristics, one phenological trait, and four photosynthesis-related measurements. Multivariate analyses of mean trait data from these eight treatments divide our rice panel into two primary groups consistent with the genetic classification of INDICA/INDICA-like and JAPONICA populations. Overall, we find that the productivity of plants grown under elevated [CO2 ] was more sensitive (negative response) to high temperature stress compared with that of plants grown under ambient [CO2 ] across this diversity panel. We report differential response to CO2 × temperature interaction for INDICA/INDICA-like and JAPONICA rice accessions and find preliminary evidence for the beneficial introduction of exotic alleles into cultivated rice genomic background. Overall, these results support the idea of using wild or currently unadapted gene pools in rice to enhance breeding efforts to secure future climate change adaptation.

Effects of pulses of elevated carbon dioxide concentration on stomatal conductance and photosynthesis in wheat and rice.

Systems for exposing plants to elevated concentrations of CO2 may expose plants to pulses of CO2 concentrations considerably above the control set point. The importance of such pulses to plant function is unknown. Single leaves of wheat (Triticum aestivum cv Choptank) and rice (Oryza sativa cv Akitakomachi) were exposed for 30 minutes to pulses of elevated CO2 similar to the frequency, duration and magnitude of pulses observed in free-air CO2 enrichment systems. Stomatal conductance decreased within a few minutes of exposure to once per minute pulses of high CO2 of all the durations tested, in both species. Both species had 20-35% lower stomatal conductance for at least 30 min after the termination of the pulses. After the pulses had stopped, in all cases photosynthesis was below the values expected for the observed substomatal CO2 concentration, which suggests that either patchy stomatal closure occurred or that photosynthesis was directly inhibited. It was also found that a single, 2 s pulse of elevated CO2 concentration reaching a maximum of 1000 µmol mol⁻¹ decreased stomatal conductance in both species. On the basis of these results, it is probable that plants in many CO2 enrichment systems have lower photosynthesis and stomatal conductance than would plants exposed to the same mean CO2 concentration but without pulses of higher concentration.

Leaf Gas Exchange and Photosystem II Fluorescence Responses to CO2 Cycling.

Experimental systems to simulate future elevated CO2 conditions in the field often have large, rapid fluctuations in CO2. To examine possible impacts of such fluctuations on photosynthesis, the intact leaves of the field-grown plants of five species were exposed to two-minute cycles of CO2 between 400 and 800 µmol mol-1, lasting a total of 10 min, with photosynthesis, stomatal conductance and PSII fluorescence measured at the end of each half-cycle and also 10 min after the end of the cycling. Prior to the cyclic CO2 treatments, the steady-state responses of leaf gas exchange and fluorescence to CO2 were determined. In four of the five species, in which stomatal conductance decreased with increasing CO2, the cyclic CO2 treatments reduced stomatal conductance. In those species, both photosynthesis and the photochemical efficiency of PSII were reduced at limiting internal CO2 levels, but not at saturating CO2. In the fifth species, there was no change in stomatal conductance with CO2 and no change in either photosynthesis or PSII efficiency at any CO2 level with CO2 cycling. It is concluded that in many, but not all, species, fluctuations in CO2 may reduce photosynthesis at low CO2, partly by decreasing the photochemical efficiency of photosystem II as well as by decreasing stomatal conductance.

Food security and climate change: on the potential to adapt global crop production by active selection to rising atmospheric carbon dioxide.

Agricultural production is under increasing pressure by global anthropogenic changes, including rising population, diversion of cereals to biofuels, increased protein demands and climatic extremes. Because of the immediate and dynamic nature of these changes, adaptation measures are urgently needed to ensure both the stability and continued increase of the global food supply. Although potential adaption options often consider regional or sectoral variations of existing risk management (e.g. earlier planting dates, choice of crop), there may be a global-centric strategy for increasing productivity. In spite of the recognition that atmospheric carbon dioxide (CO(2)) is an essential plant resource that has increased globally by approximately 25 per cent since 1959, efforts to increase the biological conversion of atmospheric CO(2) to stimulate seed yield through crop selection is not generally recognized as an effective adaptation measure. In this review, we challenge that viewpoint through an assessment of existing studies on CO(2) and intraspecific variability to illustrate the potential biological basis for differential plant response among crop lines and demonstrate that while technical hurdles remain, active selection and breeding for CO(2) responsiveness among cereal varieties may provide one of the simplest and direct strategies for increasing global yields and maintaining food security with anthropogenic change.

Unexpected Responses of Bean Leaf Size to Elevated CO2.

CO2 is currently a growth-limiting resource for plants with C3 metabolism, and elevated CO2 also often reduces stomatal conductance, reducing plant water stress. Increased photosynthesis and improved water status might be expected to result in increased leaf size. It is therefore unexpected that leaf size is in some cases reduced in plants grown at elevated CO2, and also unexpected that elevated CO2 applied only during darkness can increase leaf size. These experiments compared leaf size responses to day and/or night elevated CO2 in six cultivars of Phaseolus vulgaris grown with either constant or varying temperature in controlled environment chambers. Diverse responses of leaf size to elevated CO2 were found among the cultivars, including increased leaf size with elevated CO2 applied only during darkness in some cultivars and temperature regimes. However, leaf size responses to elevated CO2 and cultivar differences in response were unrelated to differences in leaf water potential or turgor pressure.

Crop Adaptation to Elevated CO2 and Temperature.

There is no ambiguity about the fact that both atmospheric CO2 levels and air temperatures are continuing to increase [...].

Carboxylation Capacity Can Limit C3 Photosynthesis at Elevated CO2 throughout Diurnal Cycles.

The response of carbon fixation in C3 plants to elevated CO2 is relatively larger when photosynthesis is limited by carboxylation capacity (VC) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated CO2 may be limited by VC even at limiting PPFD. These experiments were designed to test whether this also occurs in dynamic field environments. Leaf gas exchange was recorded every 5 min using two identical instruments both attached to the same leaf. The CO2 concentration in one instrument was controlled at 400 µmol mol-1 and one at 600 µmol mol-1. Leaves were exposed to ambient sunlight outdoors, and cuvette air temperatures tracked ambient outside air temperature. The water content of air in the leaf cuvettes was kept close to that of the ambient air. These measurements were conducted on multiple, mostly clear days for each of three species, Glycine max, Lablab purpureus, and Hemerocallis fulva. The results indicated that in all species, photosynthesis was limited by VC rather than J at both ambient and elevated CO2 both at high midday PPFDs and also at limiting PPFDs in the early morning and late afternoon. During brief reductions in PPFD due to midday clouds, photosynthesis became limited by J. The net result of the apparent deactivation of Rubisco at low PPFD was that the relative stimulation of diurnal carbon fixation at elevated CO2 was larger than would be predicted when assuming limitation of photosynthesis by J at low PPFD.

Three new methods indicate that CO2 concentration affects plant respiration in the range relevant to global change.

Short-term responses of plant dark respiration to carbon dioxide concentration ([CO2]) in the range anticipated in the atmosphere with global change remain controversial, primarily because it is difficult to convincingly eliminate the many possible sources of experimental error in measurements of carbon dioxide or oxygen exchange rates. Plant dark respiration is a major component of the carbon balance of many ecosystems. In seedlings without senescent tissue, the rate of loss of dry mass during darkness indicates the rate of respiration. This method of measuring respiration was used to test for [CO2] effects on respiration in seedlings of three species with relatively large seeds. The time it took respiration to exhaust substrates and cause seedling death in darkness was used as an indicator of respiration rate in four other species with smaller seeds. The third method was measuring rates of CO2 exchange in excised petioles sealed in a cuvette submerged in water to prevent leaks. Petioles were utilized as the plant tissue type with the most reliable rates of respiration, for excised tissue. The rate of loss of dry mass in the dark decreased with increasing [CO2] in the range of 200-800 µmol mol-1 in all three large-seeded species. The seedling survival time in the dark increased with [CO2] in the same concentration range in all four of the smaller-seeded species. Respiration rates of excised petioles of several species also decreased over this [CO2] range. The data provide new evidence that the rate of dark respiration in plant tissue often decreases with increasing [CO2] in the 200-800 µmol mol-1 range.

Normal Cyclic Variation in CO2 Concentration in Indoor Chambers Decreases Leaf Gas Exchange and Plant Growth.

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO2 concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO2 concentration within elevated CO2 treatments in the free-air CO2 enrichment plots raises the question of whether similar effects occur in glasshouse or indoor chamber experiments. These experiments were designed to test whether even the normal, modest, cyclic variation in CO2 concentration typical of indoor exposure systems have persistent impacts on photosynthesis and growth, and to explore mechanisms underlying the responses observed. Wheat, cotton, soybeans, and rice were grown from seed in indoor chambers at a mean CO2 concentration of 560 µmol mol-1, with "triangular" cyclic variation with standard deviations of either 4.5 or 18.0 µmol mol-1 measured with 0.1 s sampling periods with an open path analyzer. Photosynthesis, stomatal conductance, and above ground biomass at 20 to 23 days were reduced in all four species by the larger variation in CO2 concentration. Tests of rates of stomatal opening and closing with step changes in light and CO2, and tests of responses to square-wave cycling of CO2 were also conducted on individual leaves of these and three other species, using a leaf gas exchange system. Reduced stomatal conductance due to larger amplitude cycling of CO2 during growth occurred even in soybeans and rice, which had equal rates of opening and closing in response to step changes in CO2. The gas exchange results further indicated that reduced mean stomatal conductance was not the only cause of reduced photosynthesis in variable CO2 conditions.

Assessing the evolution of wheat grain traits during the last 166 years using archived samples.

The current study focuses on yield and nutritional quality changes of wheat grain over the last 166 years. It is based on wheat grain quality analyses carried out on samples collected between 1850 and 2016. Samples were obtained from the Broadbalk Continuous Wheat Experiment (UK) and from herbaria from 16 different countries around the world. Our study showed that, together with an increase in carbohydrate content, an impoverishment of mineral composition and protein content occurred. The imbalance in carbohydrate/protein content was specially marked after the 1960's, coinciding with strong increases in ambient [CO2] and temperature and the introduction of progressively shorter straw varieties. The implications of altered crop physiology are discussed.

Use of the response of photosynthesis to oxygen to estimate mesophyll conductance to carbon dioxide in water-stressed soybean leaves.

Methods of estimating the mesophyll conductance (g(m)) to the movement of CO(2) from the substomatal airspace to the site of fixation are expensive or rely upon numerous assumptions. It is proposed that, for C(3) species, measurement of the response of photosynthesis to [O(2)] at limiting [CO(2)], combined with a standard biochemical model of photosynthesis, can provide an estimate of g(m). This method was used to determine whether g(m) changed with [CO(2)] and with water stress in soybean leaves. The value of g(m) estimated using the O(2) response method agreed with values obtained using other methods. The g(m) was unchanged over the tested range of substomatal [CO(2)]. Water stress, which decreased stomatal conductance (g(s)) by about 80%, did not affect g(m), while the model parameter V(Cmax) was reduced by about 25%. Leaves with g(s) reduced by about 90% had g(m) values reduced by about 50%, while V(Cmax) was reduced by about 64%. It is concluded that g(m) in C(3) species can be conveniently estimated using the response of photosynthesis to [O(2)] at limiting [CO(2)], and that g(m) in soybean was much less sensitive to water stress than g(s), and was somewhat less sensitive to water stress than V(Cmax).

Acclimation of nitrogen uptake capacity of rice to elevated atmospheric CO2 concentration.

BACKGROUND AND AIMS: Nitrogen (N) is a major factor affecting yield gain of crops under elevated atmospheric carbon dioxide concentrations [CO(2)]. It is well established that elevated [CO(2)] increases root mass, but there are inconsistent reports on the effects on N uptake capacity per root mass. In the present study, it was hypothesized that the responses of N uptake capacity would change with the duration of exposure to elevated [CO(2)]. METHODS: The hypothesis was tested by measuring N uptake capacity in rice plants exposed to long-term and short-term [CO(2)] treatments at different growth stages in plants grown under non-limiting N conditions in hydroponic culture. Seasonal changes in photosynthesis rate and transpiration rate were also measured. KEY RESULTS: In the long-term [CO(2)] study, leaf photosynthetic responses to intercellular CO(2) concentration (Ci) were not affected by elevated [CO(2)] before the heading stage, but the initial slope in this response was decreased by elevated [CO(2)] at the grain-filling stage. Nitrate and ammonium uptake capacities per root dry weight were not affected by elevated [CO(2)] at panicle initiation, but thereafter they were reduced by elevated [CO(2)] by 31-41 % at the full heading and mid-ripening growth stages. In the short-term study (24 h exposures), elevated [CO(2)] enhanced nitrate and ammonium uptake capacities at the early vegetative growth stage, but elevated [CO(2)] decreased the uptake capacities at the mid-reproductive stage. CONCLUSIONS: This study showed that N uptake capacity was downregulated under long-term exposure to elevated [CO(2)] and its response to elevated [CO(2)] varied greatly with growth stage.

Variation in Responses of Photosynthesis and Apparent Rubisco Kinetics to Temperature in Three Soybean Cultivars.

Recent in vivo assays of the responses of Rubisco to temperature in C3 plants have revealed substantial diversity. Three cultivars of soybean (Glycine max L. Merr.), Holt, Fiskeby V, and Spencer, were grown in indoor chambers at 15, 20, and 25 °C. Leaf photosynthesis was measured over the range of 15 to 30 °C, deliberately avoiding higher temperatures which may cause deactivation of Rubisco, in order to test for differences in temperature responses of photosynthesis, and to investigate in vivo Rubisco kinetic characteristics responsible for any differences observed. The three cultivars differed in the optimum temperature for photosynthesis (from 15 to 30 °C) at 400 mmol mol-1 external CO2 concentration when grown at 15 °C, and in the shapes of the response curves when grown at 25 °C. The apparent activation energy of the maximum carboxylation rate of Rubisco differed substantially between cultivars at all growth temperatures, as well as changing with growth temperature in two of the cultivars. The activation energy ranged from 58 to 84 kJ mol-1, compared with the value of 64 kJ mol-1 used in many photosynthesis models. Much less variation in temperature responses occurred in photosynthesis measured at nearly saturating CO2 levels, suggesting more diversity in Rubisco than in electron transport thermal properties among these soybean cultivars.

Consistent Differences in Field Leaf Water-Use Efficiency among Soybean Cultivars.

High intrinsic water-use efficiency (WUEi), the ratio of leaf photosynthesis to stomatal conductance, may be a useful trait in adapting crops to water-limited environments. In soybean, cultivar differences in stomatal response to vapor pressure deficit have not consistently translated into differences in WUEi in the field. In this study, six cultivars of soybeans previously shown to differ in WUEi in indoor experiments were grown in the field in Beltsville, Maryland, and tested for mid-day WUEi on nine clear days during the mid-seasons of two years. Measurement dates were chosen for diverse temperatures, and air temperatures ranged from 21 to 34 °C on the different dates. Air saturation deficits for water vapor ranged from 0.9 to 2.2 kPa. Corrected carbon isotope delta values for 13C (CID) were determined on mature, upper canopy leaves harvested during early pod filling each year. WUEi differed among cultivars in both years and the differences were consistent across measurement dates. Correlations between mean WUEi and CID were not significant in either year. It is concluded that consistent cultivar differences in WUEi exist in these soybean cultivars under field conditions, but that carbon isotope ratios may not be useful in identifying them because of cultivar differences in mesophyll conductance.

Small bowel obstruction secondary to intramesosigmoid hernia.

Intramesosigmoid hernias are a rare cause of small bowel obstruction. Here, we present such a case with learning points derived from diagnostic dilemma, shared decision making in consent and the management of a rare cause of a common surgical emergency.

Growth, photosynthesis, nitrogen partitioning and responses to CO2 enrichment in a barley mutant lacking NADH-dependent nitrate reductase activity.

Plant growth, photosynthesis and leaf constituents were examined in the wild-type (WT) and mutant nar1 of barley (Hordeum vulgare L. cv. Steptoe) that contains a defective structural gene encoding NADH-dependent nitrate reductase (NADH-NAR). In controlled environment experiments, total biomass, rates of photosynthesis, stomatal conductance, intercellular CO(2) concentrations and foliar non-structural carbohydrate levels were unchanged or differed slightly in the mutant compared with the WT. Both genotypes displayed accelerated plant growth rates when the CO(2) partial pressure was increased from 36 to 98 Pa. Total NADH-NAR activity was 90% lower in the mutant than in the WT, and this was further decreased by CO(2) enrichment in both genotypes. Inorganic nitrate was greater in the mutant than in the WT, whereas in situ nitrate assimilation by excised leaves was two-fold greater for the WT than for the mutant. Foliar ammonia was 50% lower in the mutant than in the WT under ambient CO(2). Ammonia levels in the WT were decreased by about one-half by CO(2) enrichment, whereas ammonia was unaffected by elevated CO(2) in mutant leaves. Total soluble amino acid concentrations in WT and mutant plants grown in the ambient CO(2) treatment were 30.1 and 28.4 micromol g(-1) FW, respectively, when measured at the onset of the light period. Seven of the twelve individual amino acids reported here increased during the first 12 h of light in the ambient CO(2) treatment, leading to a doubling of total soluble amino acids in the WT. The most striking effect of the mutation was to eliminate increases of glutamine, aspartate and alanine during the latter half of the photoperiod in the ambient CO(2) treatment. Growth in elevated CO(2) decreased levels of total soluble amino acids on a diurnal basis in the WT but not in mutant barley leaves. The above results indicated that a defect in NADH-NAR primarily affected nitrogenous leaf constituents in barley. Also, we did not observe synergistic effects of CO(2) enrichment and decreased foliar NADH-NAR activity on most N-containing compounds.

Evidence of Adaptation to Recent Changes in Atmospheric CO2 in Four Weedy Species.

Seeds of three C3 and one C4 annual weedy species were collected from agricultural fields in Beltsville, Maryland in 1966 and 2006, when atmospheric CO2 concentrations averaged about 320 and 380 mol mol-1, respectively. Plants from each collection year were grown over a range of CO2 concentrations to test for adaptation of these weedy species to recent changes in atmospheric CO2. In all three of the C3 species, the increase in CO2 concentration from 320 mol mol-1 to 380 mol mol-1 increased total dry mass at 24 days in plants from seeds collected in 2006, but not in plants from seeds collected in 1966. Shoot and seed dry mass at maturity was greater at the higher growth CO2 in plants collected in 2006 than in 1966 in two of the species. Down-regulation of photosynthetic carboxylation capacity during growth at high CO2 was less in the newer seed lots than in the older in two of the species. Overall, the results indicate that adaptation to recent changes in atmospheric CO2 has occurred in some of these weedy species.