Algal vs. Macrophyte Inputs to Food Webs of Inland Saline Wetlands

Invertebrate food webs in wetlands were traditionally thought to be fueled mainly by decaying macrophytes, but recently it has been recognized that microalgae may be more important. In particular, the paradigm that shredders of vascular plant litter dominate food web processes may not apply to many wetlands where shredders are rare and microalgae more abundant. This issue is complicated by potential consumption of flocs of dissolved organic matter (DOM) released from living plants, and of exopolymer secretions (EPS) from both autotrophic and heterotrophic microbes. In Wyoming, we used gut contents and stable isotopes to investigate organic matter sources for the dominant invertebrates in oligosaline (0.5–5 g/L total dissolved solids) and mesosaline (5–18 g/L) wetlands. We examined the trophic importance of microalgae vs. macrophytes in wetlands with and without emergent vegetation (Scirpus acutus), with different growth forms and species of submersed plants (Chara spp. vs. Potamogeton pectinatus), with dominance by different microalgal types (phytoplankton, epiphyton, epipelon), and with different primary consumers (mainly amphipods vs. chironomid larvae). In all wetlands studied, guts of the major primary consumers contained little or no macrophyte tissue, but rather mostly amorphous detritus (organic particles with no recognizable cellular structure). Values of δ13C indicated that organic matter entering foodwebs was not from submersed macrophytes, but that emergent plants might be a source of DOM or EPS in amorphous detritus. However, in some wetlands, amphipods eating mainly amorphous detritus had the same δ13C values as chironomids eating a much higher fraction of diatoms, indicating that amorphous detritus was derived mainly from diatoms. Patterns of temporal change of δ13C in consumers, seston, and emergent plants supported this interpretation. We conclude that microalgae rather than macrophytes provided most organic matter for these food webs via amorphous detritus. Amorphous detritus is often thought to have poor nutrient quality and low assimilation efficiency, but this idea may not be true if amorphous detritus is largely flocs of labile DOM/EPS. Our results suggest that characterizing the origin and nature of amorphous detritus is key to understanding variations in macroinvertebrate production among saline wetlands and a broad range of wetland types

The association between physical activity and the risk of symptomatic Barrett’s oesophagus: a UK prospective cohort study

Background: Physical activity affects the functioning of the gastrointestinal system through both local and systemic effects and may play an important role in the aetiology of gastroesophageal reflux disease, Barrett’s oesophagus and oesophageal adenocarcinoma. We investigated, for the first time in a large prospective cohort study, associations between recreational and occupational levels of physical activity and the incidence of Barrett’s oesophagus. Participants and methods: The European Prospective Investigation of Cancer-Norfolk recruited 30 445 men and women between 1993 and 1997. Occupational and recreational levels of physical activity were measured using a baseline questionnaire. The cohort was followed up until 2015 to identify symptomatic cases of Barrett’s oesophagus. Cox proportional hazard regression estimated hazard ratios (HR) for physical activity and the development of disease. Results: Two hundred and three participants developed Barrett’s oesophagus (mean age: 70.6 years) the majority of whom were men (70.9%). There was an inverse association between standing occupations and disease risk [HR: 0.50, 95% confidence interval (CI): 0.31–0.82, P=0.006] when compared with sedentary jobs. Heavy manual occupations were positively associated with disease risk (HR: 1.66, 95% CI: 0.91–3.00), but conventional statistical significance was not reached (P=0.09). No associations were found between recreational activity and the risk of Barrett’s oesophagus (HR: 1.34, 95% CI: 0.72–2.50, P=0.35, highest vs. lowest levels of activity). Conclusion: Our study suggests that occupational levels of physical activity may be associated with the risk Barrett’s oesophagus. However, further work is required to confirm and describe specific occupations that may be protective

The association between preoperative cardiopulmonary exercise test variables and short-term morbidity following oesophagectomy: A hospital-based cohort study

Background: Postoperative complications after esophagectomy are thought to be associated with reduced fitness. This observational study explored the associations between aerobic fitness, as determined objectively by preoperative cardiopulmonary exercise testing (CPEX), and 30-day morbidity after esophagectomy. Methods: We retrospectively identified 254 consecutive patients who underwent esophagectomy at a single academic teaching hospital between September 2011 and March 2017. Postoperative complication data were measured using the Esophageal Complications Consensus Group definitions and graded using the Clavien-Dindo classification system of severity (blinded to cardiopulmonary exercise testing values). Associations between preoperative cardiopulmonary exercise testing variables and postoperative outcomes were estimated using logistic regression. Results: A total of 206 patients (77% male) were included in the analyses, with a mean age of 67 years (SD 9). The mean values for the maximal oxygen consumed at the peak of exercise (VO 2peak) and the anaerobic threshold were 21.1 mL/kg/min (SD 4.5) and 12.4 mL/kg/min (SD 2.8), respectively. The vast majority of patients (98.5%) had malignant disease—predominantly adenocarcinoma (84.5%), for which most received neoadjuvant chemotherapy (79%) and underwent minimally invasive Ivor Lewis esophagectomy (53%). Complications at postoperative day 30 occurred in 111 patients (54%), the majority of which were cardiopulmonary (72%). No associations were found between preoperative cardiopulmonary exercise testing variables and morbidity for either VO 2peak (OR 1.00, 95% CI 0.94–1.07) or anaerobic threshold (OR 0.98, 95% CI 0.89–1.09). Conclusion: Preoperative cardiopulmonary exercise testing variables were not associated with 30-day complications after esophagectomy. The findings do not support the use of cardiopulmonary exercise testing as an isolated preoperative screening tool to predict short-term morbidity after esophagectomy. This modestly sized observational work highlights the need for larger studies examining associations between preoperative cardiopulmonary exercise testing and outcomes after esophagectomy to look for consistency in our findings

A Gibbs approach to Chargaff's second parity rule

Chargaff's second parity rule (CSPR) asserts that the frequencies of short polynucleotide chains are the same as those of the complementary reversed chains. Up to now, this hypothesis has only been observed empirically and there is currently no explanation for its presence in DNA strands. Here we argue that CSPR is a probabilistic consequence of the reverse complementarity between paired strands, because the Gibbs distribution associated with the chemical energy between the bonds satisfies CSPR. We develop a statistical test to study the validity of CSPR under the Gibbsian assumption and we apply it to a large set of bacterial genomes taken from the GenBank repository.Comment: 16 page

Dietary Fiber and the Risk of Pancreatic Cancer

Objectives: High dietary fiber may protect against pancreatic ductal adenocarcinoma (PDAC). We investigated associations between fiber intake and the risk of PDAC using for the first time 7-day food diaries. Methods: Participants in the European Prospective Investigation Into Cancer–Norfolk completed the 7-day food diaries at recruitment. The cohort was followed up for 17 years to identify those who developed PDAC. Participants were divided into quintiles of fiber intake, and hazard ratios (HR) were estimated with their 95% confidence intervals (CIs). Fiber was tested for effect modification of high red and processed meat intake and smoking and the risk of PDAC. Results: No significant associations for any quintiles of intake (HR Q5 vs Q1, 1.08; 95% CI, 0.56–2.08) were detected with no trend across quintiles. A high-fiber diet modified positive associations between red and processed meats with the development of PDAC (HR trends, 0.89 [95% CI, 0.47–1.69] and 1.02 [95% CI, 0.55–1.88], respectively) but not those with lower fiber intake. Fiber intake did not modify the risk of PDAC in past and current smokers. Conclusion: The findings do not suggest that fiber protects against PDAC, although it may decrease potential deleterious effects of meats

An observational study to justify and plan a future phase III randomized controlled trial of metformin in improving overall survival in patients with inoperable pancreatic cancer without liver metastases

Purpose: Metformin has plausible direct and indirect anti-cancer properties against pancreatic adenocarcinoma cells. However, metformin may only be efficacious in patients with inoperable pancreatic ductal adenocarcinoma (PDAC) without liver metastases. Absorption may be decreased by gastrointestinal symptoms and proton pump inhibitors (PPIs). We aimed to justify and inform a future phase III trial of metformin versus placebo on survival in inoperable PDAC by documenting prevalence of patients meeting eligibility criteria, gastrointestinal symptoms and PPI use. Methods: Patient notes with PDAC were reviewed at a large teaching hospital over 2 years. Study variables were obtained from multiple sources of information. Results: 141 participants were identified (51.8% female), of which 37.6% were not prescribed metformin at diagnosis and had no radiological hepatic metastases. Characteristics were similar between non-metformin and metformin users. In eligible patients, 65.2% reported nausea and vomiting and 46.2% were prescribed PPIs. Conclusion: Approximately, a third of all patients with inoperable PDAC are eligible for a future trial of metformin, allowing an estimate of the number of hospitals required for recruitment. Nausea and vomiting are common and should be managed effectively to prevent trial dropouts. PPI use is frequent and their influence on metformin’s pharmacodynamic actions needs to be clarified

β3-integrin is required for differentiation in OC-2 cells derived from mammalian embryonic inner ear

<p>Abstract</p> <p>Background</p> <p>The mammalian inner ear contains the organ of Corti which is responsible for the conversion of sound into neuronal signals. This specialised epithelial tissue is the product of a complex developmental process where a common precursor cell type differentiates into the sound transducing hair cells and the non-innervated supporting cells. We hypothesised that integrin proteins, which are involved in cell attachment to extracellular matrix proteins and cellular signalling, play a role in the differentiation process of the precursor inner ear epithelial cells. To test our hypothesis we have utilised a cell line (OC-2) derived from E13 embryonic immortomouse inner ears. In vitro, by switching the incubation temperature from 33°C to 39°C, the OC-2 cells can be induced to differentiate and express hair cells markers, such as Myosin VIIa. The OC-2 cells are thus a useful model system for testing mechanism of hair cells differentiation.</p> <p>Results</p> <p>We have identified 4 integrin subunits which are expressed in OC-2 cells: α6, αv, β1 and β3. Among these, the relative level of expression of the αv, β1 and β3 subunits increased in a time dependent manner when the cells were exposed to the differentiating temperature of 39°C, most notably so for β3 which was not detectable at 33°C. Treatment of fully differentiated OC-2 cells with siRNA against the four integrin subunits reduced the expression of not only the respective integrin proteins but also of the hair cell marker Myosin VIIa. Conversely over-expression of β3 was sufficient to induce the expression of Myosin VIIa at 33°C.</p> <p>Conclusions</p> <p>Our data demonstrate that modulation of integrin expression is associated with the differentiation process of the OC-2 cells. This suggests that the maturation of the organ of Corti, from where OC-2 cells are derived, may also depend on changes of gene expression associated with integrin expression.</p

No Association Between Consumption of Sweetened Beverages and Risk of Later-Onset Crohn's Disease or Ulcerative Colitis

Background & Aims: Consumption of sweetened beverages has been associated with inflammation based on measurements of C-reactive protein and tumor necrosis factor, as well as immune-mediated disorders including rheumatoid arthritis. We investigated associations with Crohn's disease (CD) or ulcerative colitis (UC). Methods: We conducted a prospective cohort study of 83,042 participants (age, 44–83 y) enrolled in the Cohort of Swedish Men or the Swedish Mammography Study. Dietary and lifestyle data were collected using a validated food frequency questionnaire at baseline in 1997. Diagnoses of CD and UC were ascertained from the Swedish Patient Register. We used Cox proportional hazards modeling to calculate hazard ratios and 95% CIs. Results: Through December of 2014, we confirmed 143 incident cases of CD (incidence rate, 11 cases/100,000 person-years) and 349 incident cases of UC (incidence rate, 28 cases/100,000 person-years) over 1,264,345 person-years of follow-up evaluation. Consumption of sweetened beverages was not associated with increased risk of CD (Ptrend = .34) or UC (Ptrend = .40). Compared with participants who reported no consumption of sweetened beverages, the multivariable-adjusted hazard ratios for 1 or more servings per day were 1.02 for CD (95% CI, 0.60–1.73) and 1.14 for UC (95% CI, 0.83–1.57). The association between consumption of sugar-sweetened beverages and risk of CD or UC were not modified by age, sex (cohort), body mass index, or smoking (all Pinteraction ≥ .12). Conclusions: In analyses of data from 2 large prospective cohort studies from Sweden, we observed no evidence for associations between consumption of sweetened beverages and later risk of CD or UC