Pneumatosis Coli Associated with Pseudomembranous Colitis in a Patient following Colonic Surgery

Pneumatosis intestinalis is a rare disorder characterized by gas-filled cysts within the subserosal and/or submucosal regions of the intestinal wall. The source of this gas and its translocation across the mucosa is incompletely understood. Most (85%) cases are associated with medical conditions, ranging from psychiatric through respiratory disorders to gastrointestinal-related diseases; the remaining 15% lack any recognizable cause or association. In this case report, pneumatosis coli (affecting the colon) occurred in a patient following abdominal surgery and was associated with pseudomembranous colitis, which was Clostridium difficile toxin negative—presumably a false negative. Supportive care and appropriate antibacterial agents sufficed to alleviate symptoms and resolve the pneumatosis. Recognizing this uncommon but important association can avoid high financial and personal costs from unnecessary testing and invasive surgical explorations. Consideration should be given to pseudomembranous colitis as the basis for pneumatosis coli developing in patients who have received antibiotics, once gut ischemia has been ruled out

Perceived Self-Efficacy, Confidence, and Skill Among Factors of Adult Patient Participation in Transitional Care: A Systematic Review of Quantitative Studies.

Introduction: An advancing healthcare system in which patients are often required to self-manage care needs across countless settings and clinicians is increasing focus on participation in care. Mismanagement of care during already risky care-transitions further increases adverse care outcomes. Understanding factors of patient participation in transitional care in an adult population can help guide ways to reduce this burden. Methods: A systematic review of the literature guided by the PRISMA method was conducted to identify factors of patient participation in transitional care. Quantitative studies in which patient participation was measured as an outcome variable and related statistics reported, and data were collected from an adult sample, were included. Two authors independently reviewed, critiqued, and synthesized the articles, and later categorized study variables according to identified trends. Results: Twelve studies across international and multidisciplinary backgrounds were identified. Across studies, efforts were largely based on understanding or improving patient self-management of care during transitions. The majority of studies were experimental and care interventions grounded in patient and healthcare team partnerships, delivered beyond the hospital setting. An array of measures was used to quantify patient participation. Factors of patient participation in transitional care included higher perceived levels of self-efficacy, confidence, and skills to participate in care. Conclusion: The results of this study suggest patient participation in transitional care is largely based on perceptions of self-efficacy, confidence, and skill. Patient-centric transitional care interventions targeting these factors and delivered beyond the hospital setting may improve care outcomes. Implications and direction for further studies includes conceptual clarity, the study of a broader-reaching patient population demographic, and use of multidisciplinary interventions. Outcome variables should remain focused on patient perception of care involvement and participation and expanded to include variables such as functional abilities and social determinants of health

Evolutionary history determines how plant productivity responds to phylogenetic diversity and species richness

The relationship between biodiversity and ecosystem function has received a great deal of attention in ecological research and recent results, from re-analyses, suggest that ecosystem function improves with increases in phylogenetic diversity. However, many of these results have been generalized across a range of different species and clades, and plants with different evolutionary histories could display different relationships between biodiversity and ecosystem function. To experimentally test this hypothesis, we manipulated species richness and phylogenetic diversity using 26 species from two subgenera of the genus Eucalyptus (subgenus Eucalyptus and subgenus Symphyomyrtus). We found that plant biomass (a measurement of ecosystem function) sometimes, but not always, responded to increases in species richness and phylogenetic diversity. Specifically, Symphyomyrtus plants showed a positive response while no comparable effect was observed for Eucalyptus plants, showing that responses to biodiversity can vary across different phylogenetic groups. Our results show that the impacts of evolutionary history may complicate the relationship between the diversity of plant communities and plant biomass

Trait Variation Along Elevation Gradients in a Dominant Wood Shrub is Population-Specific and Driven by Plasticity

Elevation gradients are frequently used as space-for-time substitutions to infer species’ trait responses to climate change. However, studies rarely investigate whether trait responses to elevation are widespread or population specific within a species, and the relative genetic and plastic contributions to such trait responses may not be well understood. Here, we examine plant trait variation in the dominant woody shrub, Rhododendron maximum, along elevation gradients in three populations in the South Central Appalachian Mountains, USA, in both field and common garden environments. We ask the following: (1) do plant traits vary along elevation? (2) do trait responses to elevation differ across populations, and if so, why? and (3) does genetic differentiation or phenotypic plasticity drive trait variation within and among populations? We found that internode length, shoot length, leaf dry mass, and leaf area varied along elevation, but that these responses were generally unique to one population, suggesting that trait responses to environmental gradients are population-specific. A common garden experiment identified nogenetic basis to variation along elevation or among populations in any trait, suggesting that plasticity drives local and regional trait variation and may play a key role in the persistence of plant species such as R. maximum with contemporary climate change. Overall, our findings highlight the importance of examining multiple locations in future elevation studies and indicate that, for a given plant species, the magnitude of trait responses to global climate change may vary by location

Characterization of Dextromethorphan And Dextrorphan Uptake by a Putative Glutamic Acid Carrier and Passive Diffusion Across Brain Microvessel Endothelium

Read More: http://informahealthcare.com/doi/abs/10.3109/10717549309022764The mechanisms of uptake and transcellular passage of dextromethorphan (DM) and its major metabolite dextrorphan (DX) across the endothelial component of the blood–brain barrier have been investigated with primary cultures of bovine brain microvessel endothelial cells (BMECs). The uptake of [14C]DM and [14C]DX by BMECs was observed to be temperature-sensitive and saturable, with approximate Km's of 0.12 and 0.29 mM and Vmax's of 9.2 and 11.0 pmol/mg/min, respectively. The BMEC uptake of [14C] DM was inhibited half-maximally by approximately 0.57 mM L-glutamic acid, 0.71 mM N-methyl-d-asparatate (NMDA), and 0.99 mM DL-threo-β-hydroxyaspartic acid. The BMEC uptake of [14C]DX was inhibited half-maximally by approximately 0.48 mM L-glutamic acid, 1.50 mM NMDA, and 0.69 mM DL-threo-β-hydroxyaspartic acid. Conversely, the bidirectional passage of DM and DX across confluent BMEC monolayers occurred at a faster rate but was neither saturable nor inhibited by high concentrations of glutamic acid, NMDA, or unlabeled DM or DX. These results suggest that DM and DX are capable of interacting with a low-capacity glutamic acid-type carrier mechanism on the apical surface of BMECs. However, the net transfer of these agents across BMEC monolayers appeared to be more rapid and passive in nature

Opportunities for Self-Evaluation Increase Student Calibration in an Introductory Biology Course

Accurate self-evaluation is critical for learning. Calibration describes the relationship between learners’ perception of their performance and their actual performance on a task. Here, we describe two studies aimed at assessing and improving student calibration in a first-semester introductory biology course at a 4-year public institution. Study 1 investigated students’ (n = 310) calibration (the difference between estimated and actual exam performance) across one semester. Students were significantly miscalibrated for the first exam: their predicted scores were, on average, significantly higher than their actual scores. The lowest-performing students had the most inaccurate estimates. Calibration improved with each exam. By the final exam, students underestimated their scores. We initiated a second study in the following semester to examine whether explicitly teaching students about self-evaluation strategies would improve their calibration and performance. Instruction in the experimental section (n = 290) focused on students’ tendency to overestimate their abilities and provided retrieval-practice opportunities. Students in the experimental section showed better calibration and performance on the first exam compared with students in a control section taught by a different instructor during the same semester (n = 251). These findings suggest that simple instructional strategies can increase students’ metacognitive awareness and improve their performance

Shifts in Species Interactions Due to the Evolution of Functional Differences between Endemics and Non-Endemics: An Endemic Syndrome Hypothesis

Species ranges have been shifting since the Pleistocene, whereby fragmentation, isolation, and the subsequent reduction in gene flow have resulted in local adaptation of novel genotypes and the repeated evolution of endemic species. While there is a wide body of literature focused on understanding endemic species, very few studies empirically test whether or not the evolution of endemics results in unique function or ecological differences relative to their widespread congeners; in particular while controlling for environmental variation. Using a common garden composed of 15 Eucalyptus species within the subgenus Symphyomyrtus (9 endemic to Tasmania, 6 non-endemic), here we hypothesize and show that endemic species are functionally and ecologically different from non-endemics. Compared to non-endemics, endemic Eucalyptus species have a unique suite of functional plant traits that have extended effects on herbivores. We found that while endemics occupy many diverse habitats, they share similar functional traits potentially resulting in an endemic syndrome of traits. This study provides one of the first empirical datasets analyzing the functional differences between endemics and non-endemics in a common garden setting, and establishes a foundation for additional studies of endemic/non-endemic dynamics that will be essential for understanding global biodiversity in the midst of rapid species extinctions and range shifts as a consequence of global change

Katanin catalyzes microtubule depolymerization independently of tubulin C-terminal tails

Microtubule network remodeling is an essential process for cell development, maintenance, cell division, and motility. Microtubule‐severing enzymes are key players in the remodeling of the microtubule network; however, there are still open questions about their fundamental biochemical and biophysical mechanisms. Here, we explored the ability of the microtubule‐severing enzyme katanin to depolymerize stabilized microtubules. Interestingly, we found that the tubulin C‐terminal tail (CTT), which is required for severing, is not required for katanin‐catalyzed depolymerization. We also found that the depolymerization of microtubules lacking the CTT does not require ATP or katanin\u27s ATPase activity, although the ATP turnover enhanced depolymerization. We also observed that the depolymerization rate depended on the katanin concentration and was best described by a hyperbolic function. Finally, we demonstrate that katanin can bind to filaments that lack the CTT, contrary to previous reports. The results of our work indicate that microtubule depolymerization likely involves a mechanism in which binding, but not enzymatic activity, is required for tubulin dimer removal from the filament ends

Identification and Characterisation of an Iron-Responsive Candidate Probiotic

Background: Iron is an essential cofactor in almost all biological systems. The lactic acid bacteria (LAB), frequently employed as probiotics, are unusual in having little or no requirement for iron. Iron in the human body is sequestered by transferrins and lactoferrin, limiting bacterial growth. An increase in the availability of iron in the intestine by bleeding, surgery, or under stress leads to an increase in the growth and virulence of many pathogens. Under these high iron conditions, LAB are rapidly out-competed; for the levels of probiotic bacteria to be maintained under high iron conditions they must be able to respond by increasing growth rate to compete with the normal flora. Despite this, iron-responsive genera are poorly characterised as probiotics. Methodology/Principal Findings: Here, we show that a panel of probiotics are not able to respond to increased iron availability, and identify an isolate of Streptococcus thermophilus that can increase growth rate in response to increased iron availability. The isolate of S. thermophilus selected was able to reduce epithelial cell death as well as NF-kB signalling and IL-8 production triggered by pathogens. It was capable of crossing an epithelial cell barrier in conjunction with E. coli and downregulating Th1 and Th17 responses in primary human intestinal leukocytes. Conclusions/Significance: We propose that an inability to compete with potential pathogens under conditions of high iron availability such as stress and trauma may contribute to the lack of efficacy of many LAB-based probiotics in treatin