A case report of iatrogenic gas gangrene post colonoscopy successfully treated with conservative management- is surgery always necessary?

Background: Colonoscopy is a routine procedure in diagnosis and treatment of colonic disease. While generally regarded as a safe procedure, potentially fatal complications can occur. Gas gangrene is one such complication, with very high mortality. There are few cases of gas gangrene occurring after colonoscopy, making it one of the rarer complications of this procedure. There have been no previously reported cases of a patient surviving such an infection and the optimal treatment strategy is contentious. This report describes a case of intramural gas gangrene of the colon, treated conservatively with antibiotic therapy in which the patient survived with full recovery. Case presentation: A 71-year-old, previously healthy male presented 6 h post apparently uncomplicated colonoscopic polypectomy with rigors, nausea, vomiting and right upper quadrant pain. At presentation he was febrile at 40.1 °C but hemodynamically stable. Abdominal computed tomography revealed substantial colonic thickening and several focal intramural gas bubbles (pneumatosis intestinalis) surrounding the polypectomy site. Within 24 h post procedure he became hypotensive and was admitted to ICU in frank septic shock requiring inotropes, and with demonstrable septic myocardial depression. Bloods showed multi-organ derangement with leukocytosis, lactic acidosis, haemolytic anaemia and hyperbilirubinemia. A diagnosis of presumed Clostridial gas gangrene was made, and treatment was initiated with benzylpenicillin, clindamycin, metronidazole and vancomycin. After 4 days in ICU he was stepped down, and discharged after a further 10 days with no surgical or endoscopic interventions. At three-month review he reported being back to full health. Conclusions: This case demonstrates that gas gangrene infection is a possible complication of colonoscopic polypectomy. This is a cause of rapid deterioration in post-colonoscopy patients and has been misdiagnosed as colonic perforation in previously reported cases of retroperitoneal gas gangrene. Such misdiagnosis delays antibiotic therapy, which likely plays a role in the high mortality of this condition. Early diagnosis and initiation of antibiotic therapy with benzylpenicillin and clindamycin as seen in this case is essential for patient survival. While surgery is typically performed, non-operative management of pneumatosis intestinalis, and potentially gas gangrene is becoming more common and was utilized effectively in this patient

Using genetic algorithms to uncover individual differences in how humans represent facial emotion

Emotional facial expressions critically impact social interactions and cognition. However, emotion research to date has generally relied on the assumption that people represent categorical emotions in the same way, using standardized stimulus sets and overlooking important individual differences. To resolve this problem, we developed and tested a task using genetic algorithms to derive assumption-free, participant-generated emotional expressions. One hundred and five participants generated a subjective representation of happy, angry, fearful and sad faces. Population-level consistency was observed for happy faces, but fearful and sad faces showed a high degree of variability. High test-retest reliability was observed across all emotions. A separate group of 108 individuals accurately identified happy and angry faces from the first study, while fearful and sad faces were commonly misidentified. These findings are an important first step towards understanding individual differences in emotion representation, with the potential to reconceptualize the way we study atypical emotion processing in future research

Plasmodium falciparum ligand binding to erythrocytes induce alterations in deformability essential for invasion

The most lethal form of malaria in humans is caused by Plasmodium falciparum. These parasites invade erythrocytes, a complex process involving multiple ligand-receptor interactions. The parasite makes initial contact with the erythrocyte followed by dramatic deformations linked to the function of the Erythrocyte binding antigen family and P. falciparum reticulocyte binding-like families. We show EBA-175 mediates substantial changes in the deformability of erythrocytes by binding to glycophorin A and activating a phosphorylation cascade that includes erythrocyte cytoskeletal proteins resulting in changes in the viscoelastic properties of the host cell. TRPM7 kinase inhibitors FTY720 and waixenicin A block the changes in the deformability of erythrocytes and inhibit merozoite invasion by directly inhibiting the phosphorylation cascade. Therefore, binding of P. falciparum parasites to the erythrocyte directly activate a signaling pathway through a phosphorylation cascade and this alters the viscoelastic properties of the host membrane conditioning it for successful invasion

Prospective study of the safety and effectiveness of droperidol in elderly patients for pre-hospital acute behavioural disturbance

Objective: Acute behavioural disturbance in the elderly (≥65 years) is a significant issue for emergency medical services with increasing prevalence of dementia and aging populations. We investigated the pre-hospital safety and effectiveness of droperidol in the elderly with acute behavioural disturbance. Methods: This was a pre-hospital prospective observational 1-year study of elderly patients with acute behavioural disturbance. The primary outcome was proportion of adverse events (AEs) (airway intervention, oxygen saturatio

Observations and comparisons of cloud microphysical properties in spring and summertime Arctic stratocumulus clouds during the ACCACIA campaign

Measurements from four case studies in spring and summer-time Arctic stratocumulus clouds during the Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) campaign are presented. We compare microphysics observations between cases and with previous measurements made in the Arctic and Antarctic. During ACCACIA, stratocumulus clouds were observed to consist of liquid at cloud tops, often at distinct temperature inversions. The cloud top regions precipitated low concentrations of ice into the cloud below. During the spring cases median ice number concentrations (~ 0.5 L−1) were found to be lower by about a factor of 5 than observations from the summer campaign (~ 3 L−1). Cloud layers in the summer spanned a warmer temperature regime than in the spring and enhancement of ice concentrations in these cases was found to be due to secondary ice production through the Hallett–Mossop (H–M) process. Aerosol concentrations during spring ranged from ~ 300–400 cm−3 in one case to lower values of ~ 50–100 cm−3 in the other. The concentration of aerosol with sizes Dp > 0.5 μm was used in a primary ice nucleus (IN) prediction scheme (DeMott et al., 2010). Predicted IN values varied depending on aerosol measurement periods but were generally greater than maximum observed median values of ice crystal concentrations in the spring cases, and less than the observed ice concentrations in the summer due to the influence of secondary ice production. Comparison with recent cloud observations in the Antarctic summer (Grosvenor et al., 2012), reveals lower ice concentrations in Antarctic clouds in comparable seasons. An enhancement of ice crystal number concentrations (when compared with predicted IN numbers) was also found in Antarctic stratocumulus clouds spanning the H–M temperature zone; however, concentrations were about an order of magnitude lower than those observed in the Arctic summer cases but were similar to the peak values observed in the colder Arctic spring cases, where the H–M mechanism did not operate

Are Kaluza-Klein modes enhanced by parametric resonance?

We study parametric amplification of Kaluza-Klein (KK) modes in a higher $D$-dimensional generalized Kaluza-Klein theory, which was originally considered by Mukohyama in the narrow resonance case. It was suggested that KK modes can be enhanced by an oscillation of a scale of compactification by the $d$-dimensional sphere $S^d~(d=D-4)$ and by the direct product $S^{d_1}\times S^{d_2}~(d_1+d_2=D-4)$. We extend this past work to the more general case where initial values of the scale of compactification and the quantum number of the angular momentum $l$ of KK modes are not small. We perform analytic approaches based on the Mathieu equation as well as numerical calculations, and find that the expansion of the universe rapidly makes the KK field deviate from instability bands. As a result, KK modes are not enhanced sufficiently in an expanding universe in these two classes of models.Comment: 15 pages, 5 figure

Genetic Specificity of Hippocampal Subfield Volumes, Relative to Hippocampal Formation, Identified in 2148 Young Adult Twins and Siblings

The hippocampus is a complex brain structure with key roles in cognitive and emotional processing and with subregion abnormalities associated with a range of disorders and psychopathologies. Here we combine data from two large independent young adult twin/sibling cohorts to obtain the most accurate estimates to date of genetic covariation between hippocampal subfield volumes and the hippocampus as a single volume. The combined sample included 2148 individuals, comprising 1073 individuals from 627 families (mean age = 22.3 years) from the Queensland Twin IMaging (QTIM) Study, and 1075 individuals from 454 families (mean age = 28.8 years) from the Human Connectome Project (HCP). Hippocampal subfields were segmented using FreeSurfer version 6.0 (CA4 and dentate gyrus were phenotypically and genetically indistinguishable and were summed to a single volume). Multivariate twin modeling was conducted in OpenMx to decompose variance into genetic and environmental sources. Bivariate analyses of hippocampal formation and each subfield volume showed that 10%–72% of subfield genetic variance was independent of the hippocampal formation, with greatest specificity found for the smaller volumes; for example, CA2/3 with 42% of genetic variance being independent of the hippocampus; fissure (63%); fimbria (72%); hippocampus-amygdala transition area (41%); parasubiculum (62%). In terms of genetic influence, whole hippocampal volume is a good proxy for the largest hippocampal subfields, but a poor substitute for the smaller subfields. Additive genetic sources accounted for 49%–77% of total variance for each of the subfields in the combined sample multivariate analysis. In addition, the multivariate analyses were sufficiently powered to identify common environmental influences (replicated in QTIM and HCP for the molecular layer and CA4/dentate gyrus, and accounting for 7%–16% of total variance for 8 of 10 subfields in the combined sample). This provides the clearest indication yet from a twin study that factors such as home environment may influence hippocampal volumes (albeit, with caveats)

Inflation Dynamics and Reheating

We review the theory of inflation with single and multiple fields paying particular attention to the dynamics of adiabatic and entropy/isocurvature perturbations which provide the primary means of testing inflationary models. We review the theory and phenomenology of reheating and preheating after inflation providing a unified discussion of both the gravitational and nongravitational features of multi-field inflation. In addition we cover inflation in theories with extra dimensions and models such as the curvaton scenario and modulated reheating which provide alternative ways of generating large-scale density perturbations. Finally we discuss the interesting observational implications that can result from adiabatic-isocurvature correlations and non-Gaussianity.Comment: 51 pages, latex, 16 figures, version to appear in Reviews of Modern Physic