What is the optimal management of an intra-operative air leak in a colorectal anastomosis?

AIM: An airtight anastomosis on intra-operative leak testing has been previously demonstrated to be associated with a lower risk of clinically significant postoperative anastomotic leak following left-sided colorectal anastomosis. However, to date, there is no consistently agreed upon method for management of an intra-operative anastomotic leak. Therefore, we powered a noninferiority study to determine whether suture repair alone was an appropriate strategy for the management of an intra-operative air leak. METHOD: This is a retrospective cohort analysis of prospectively collected data from a tertiary care referral centre. We included all consecutive patients with left-sided colorectal or ileorectal anastomoses and evidence of air leak during intra-operative leak testing. Patients were excluded if proximal diversion was planned preoperatively, a pre-existing proximal diversion was present at the time of surgery or an anastomosis was ultimately unable to be completed. The primary outcome measure was clinically significant anastomotic leak, as defined by the Surgical Infection Study Group at 30 days. RESULTS: From a sample of 2360 patients, 119 had an intra-operative air leak during leak testing. Sixty-eight patients underwent suture repair alone and 51 underwent proximal diversion or anastomotic reconstruction. The clinically significant leak rate was 9% (6/68; 95% CI: 2-15%) in the suture repair alone arm and 0% (0/51) in the diversion or reconstruction arm. CONCLUSION: Suture repair alone does not meet the criteria for noninferiority for the management of intra-operative air leak during left-sided colorectal anastomosis. Further repair of intra-operative air leak by suture repair alone should be reconsidered given these findings.

Post-discharge mortality in patients hospitalized with MRSA infection and/or colonization.

Methicillin-resistant Staphylococcus aureus (MRSA) infection is known to increase in-hospital mortality, but little is known about its association with long-term health. Two hundred and thirty-seven deaths occurred among 707 patients with MRSA infection at the time of hospitalization and/or nasal colonization followed for almost 4 years after discharge from the Atlanta Veterans Affairs Medical Center, USA. The crude mortality rate in patients with an infection and colonization (23·57/100 person-years) was significantly higher than the rate in patients with only colonization (15·67/100 person-years, P = 0·037). MRSA infection, hospitalization within past 6 months, and histories of cancer or haemodialysis were independent risk factors. Adjusted mortality rates in patients with infection were almost twice as high compared to patients who were only colonized: patients infected and colonized [hazard ratio (HR) 1·93, 95% confidence interval (CI) 1·31-2·84]; patients infected but not colonized (HR 1·96, 95% CI 1·22-3·17). Surviving MRSA infection adversely affects long-term mortality, underscoring the importance of infection control in healthcare settings.

Self-reported gastrointestinal disorders among veterans with gulf war illness with and without posttraumatic stress disorder.

BACKGROUND: Gulf War Illness (GWI) is a chronic, multi-symptom disorder affecting 25%-32% of Gulf War veterans. Veterans with GWI disproportionately suffer from gastrointestinal (GI) disorders. Given the increasing evidence supporting a gut-brain axis, we explore the relationship between post-traumatic stress disorder (PTSD), GWI, and self-reported GI disorders among GW veterans. METHODS: Veterans from the Gulf War Era Cohort and Biorepository responded to a mail-based survey (N = 1058). They were stratified by GWI (Centers for Disease Control definition) and PTSD status. This yielded three groups: GWI-, GWI+/PTSD-, and GWI+/PTSD+. Multivariable logistic regression adjusting for demographic and military characteristics examined associations between GWI/PTSD groups and GI disorders. Results were expressed as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI). KEY RESULTS: The most frequently reported GI disorders were irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD), and colon polyps (CP). The GWI+/PTSD+ group had a higher odds of these disorders than the GWI+/PTSD- group (aORIBS  = 3.12, 95% CI: 1.93-5.05; aORGERD  = 2.04, 95% CI: 1.44-2.90; aORCP  = 1.85, 95% CI: 1.23-2.80), which had a higher odds of these disorders than the GWI- group (aORIBS  = 4.38, 95% CI: 1.55-12.36; aORGERD  = 2.51 95% CI: 1.63-3.87; aORCP  = 2.57, 95% CI: 1.53-4.32). CONCLUSIONS & INFERENCES: GW veterans with GWI and PTSD have significantly higher odds of specific self-reported GI disorders than the other groups. Given the known bidirectional influences of the gut and brain, these veterans may benefit from a holistic healthcare approach that considers biopsychosocial contributors to the assessment and management of disease.

Mass flux of dispersed particles in turbulence: Representations and the influence of correlation structure in gravitational settling.

Different integral representations for the mass flux of inertial particles transported by turbulent gas flows have been proposed. These are discussed and analyzed. Each formulation provides its own insights into the underlying physical processes governing the resulting flux. However, none of the representations, as it stands, provides an explicit closed-form expression in terms of known statistical properties of the flow and parameters governing particle dynamics. We consider the representations in terms of their potential for reduction to closed-form models. To enable an analysis uncomplicated by the presence of many coupled interactions, we confine our attention to the classic test case of monodisperse particles in homogeneous, isotropic turbulent flows, and subject to a uniform gravitational field. The modification of the mean particle settling velocity resulting from their preferential sampling of fluid velocities is captured by the flux representations. A distribution-based symmetry analysis coupled with a correlation splitting technique is used to reduce and simplify the terms appearing in the flux integrals. This prompts a strategy for closure modeling of the resulting expressions in terms of correlations between the sampled fluid velocity and fluid strain-rate fields. Results from particle-trajectory-based simulations are presented to assess the potential of this closure strategy.

Wrinkling and strain softening in single-wall carbon nanotube membranes.

The nonlinear elasticity of thin supported membranes assembled from length purified single-wall carbon nanotubes is analyzed through the wrinkling instability that develops under uniaxial compression. In contrast with thin polymer films, pristine nanotube membranes exhibit strong softening under finite strain associated with bond slip and network fracture. We model the response as a shift in percolation threshold generated by strain-induced nanotube alignment in accordance with theoretical predictions.

Elastic constants and dimensions of imprinted polymeric nanolines determined from Brillouin light scattering.

Elastic constants and cross-sectional dimensions of imprinted nanolines of poly(methyl methacrylate) (PMMA) on silicon substrates are determined nondestructively from finite-element inversion analysis of dispersion curves of hypersonic acoustic modes of these nanolines measured with Brillouin light scattering. The results for the cross-sectional dimensions, under the simplifying assumption of vertical sides and a semicircular top, are found to be consistent with dimensions determined from critical-dimension small-angle x-ray scattering measurements. The elastic constants C(11) and C(44) are found to be, respectively, 11.6% and 3.1% lower than their corresponding values for bulk PMMA. This result is consistent with the dimensional dependence of the quasi-static Young's modulus determined from buckling measurements on PMMA films with lower molecular weights. This study provides the first evidence of size-dependent effects on hypersonic elastic properties of polymers.

Thermoelectric signatures of coherent transport in single-molecule heterojunctions.

An exact expression for the heat current in an interacting nanostructure is derived and used to calculate the thermoelectric response of three representative single-molecule junctions formed from isoprene, 1,3-benzenedithiol, and [18]-annulene. Dramatic enhancements of the thermopower S and Lorenz number L are predicted when the junction is tuned across a node in the transmission function, with universal maximum values S(max) = (pi/3(1/2))(k(B)/e) and L(max) = (7pi(2)/5)(k(B)(2)/e(2)). The effect of a finite minimum transmission probability due, e.g., to incoherent processes or additional nonresonant channels, is also considered.

Order of phase transitions in barrier crossing.

A spatially extended classical system with metastable states subject to weak spatiotemporal noise can exhibit a transition in its activation behavior when one or more external parameters are varied. Depending on the potential, the transition can be first or second order, but there exists no systematic theory of the relation between the order of the transition and the shape of the potential barrier. In this paper, we address that question in detail for a general class of systems whose order parameter is describable by a classical field that can vary in both space and time, and whose zero-noise dynamics are governed by a smooth polynomial potential. We show that a quartic potential barrier can have only second-order transitions, confirming an earlier conjecture [D. L. Stein, J. Stat. Phys. 114, 1537 (2004)]. We then derive, through a combination of analytical and numerical arguments, both necessary and sufficient conditions to have a first-order vs a second-order transition in noise-induced activation behavior, for a large class of systems with smooth polynomial potentials of arbitrary order. We find in particular that the order of the transition is especially sensitive to the potential behavior near the top of the barrier.

Cholesterol and bile acid balance in Macaca fascicularis. Effects of alfalfa saponins.

We determine the effects of alfalfa top saponins on cholesterol and bile acid balance in eight cynomolgus macaques (Macaca fascicularis). The monkeys ate semipurified food containing cholesterol with or without added saponins. The saponins decreased cholesterolemia without changing the levels of high density lipoprotein-cholesterol; hence, they reduced the total cholesterol/high density lipoprotein-cholesterol ratio. Furthermore, they decreased intestinal absorption of cholesterol, increased fecal excretion of endogenous and exogenous neutral steroids and bile acids, and decreased the percent distribution of fecal deoxycholic and lithocholic acids. The fecal excretion of fat was also slightly increased, but steatorrhea did not occur. We saw no signs of toxicity in the monkeys after 6 or 8 wk of saponin ingestion. The data suggest that alfalfa top saponins may be of use in the treatment of patients with hypercholesterolemia, but long-term studies on possible toxicity are needed before this therapy can be recommended for humans.

Rabi oscillations at exceptional points in microwave billiards.

We experimentally investigated the decay behavior with time t of resonances near and at exceptional points, where two complex eigenvalues and also the associated eigenfunctions coalesce. The measurements were performed with a dissipative microwave billiard, whose shape depends on two parameters. The t2 dependence predicted at the exceptional point on the basis of a two-state matrix model could be verified. Outside the exceptional point the predicted Rabi oscillations, also called quantum echoes in this context, were detected.

A pan-neotropical analysis of hunting preferences.

Hunting in the neotropics is a widespread form of resource extraction. However, there is increasing concern that current activities are leading to the decline and extirpation of vulnerable species; particulary ateline primates, large ungulates (such as tapirs and white-lipped peccaries) and large birds such as curassows. Hunting patterns are expected to be a product of two principal influences: the value of return for a given amount of effort invested into hunting, and cultural factors that determine the prestige and usefulness of prey. Previous work has suggested that hunting profiles change in a predictable way over time, becoming more diverse and more dependent on smaller bodied species as preferred, large-bodied prey become scarcer. In this paper, we evaluate the hunting profiles of 78 neotropical communities in Central and South America. We investigate the uniformity of species preferences, whether communities that are geographically closer have similar hunting profiles, and whether the age and size of settlements can be used to predict the type and diversity of species targeted. We found that there was only a weak correlation between the structure of communities' hunting profiles and their geographical proximity. Neither a community's size nor age was a good predictor of the shape and structure of its hunting profile. Our data suggest that either the availability of prey or the cultural influences dictating the value of different species can change rapidly over small distances, and that older and larger settlements do not impact prey species distributions in a predictable way.

Enhancing single-wall carbon nanotube properties through controlled endohedral filling.

Chemical control of the endohedral volume of single-wall carbon nanotubes (SWCNTs) via liquid-phase filling is established to be a facile strategy to controllably modify properties of SWCNTs in manners significant for processing and proposed applications. Encapsulation of over 20 different compounds with distinct chemical structures, functionalities, and effects is demonstrated in SWCNTs of multiple diameter ranges, with the ability to fill the endohedral volume based on the availability of the core volume and compatibility of the molecule's size with the cross-section of the nanotube's cavity. Through exclusion of ingested water and selection of the endohedral chemical environment, significant improvements to the optical properties of dispersed SWCNTs such as narrowed optical transition linewidths and enhanced fluorescence intensities are observed. Examples of tailoring modified properties towards applications or improved processing by endohedral passivation are discussed.

Prevention of hypercholesterolemia in monkeys (Macaca fascicularis) by digitonin.

Digitonin mixed in the diet was well tolerated by rats and cynomolgus monkeys (Macaca fascicularis), and prevented the expected rise in plasma cholesterol in monkeys fed a diet containing butter and cholesterol. Both digitonin and mildly hydrolyzed digitonin precipitated cholesterol dispersed in micellar suspensions and decreased intestinal absorption of cholesterol in rats, but only digitonin bound cholesterol in vitro. The hypocholesterolemic effect of digitonin may be secondary to decreased intestinal absorption of cholesterol associated with a disturbance in the micellar suspension of cholesterol in the intestinal content. Modification of other mechanisms that may be involved in membrane transport of cholesterol through the intestinal epithelium is not ruled out by the present findings.

Comparative effects of alfalfa saponins and alfalfa fiber on cholesterol absorption in rats.

Intestinal absorption of cholesterol was measured in control rats fed semipurified diets and in rats fed alfalfa meal, in which saponins had been previously extracted, or this extracted material plus alfalfa saponins. A dose of 2 mg radioactive cholesterol was administered intragastrically, and fecal excretion of labeled neutral steroids measured. Absorption of cholesterol was about 76% in control animals, and about 47% in alfalfa-red rats. Extraction of saponins from alfalfa eliminated the cholesterol absorption-lowering effect, while addition of 0.26% alfalfa saponins to the extracted alfalfa restored its activity. The results demonstrate that alfalfa saponins are responsible for the effect of alfalfa meal in reducing cholesterol absorption, and that alfalfa fiber is not involved in this activity.

Effect of alfalfa saponins on intestinal cholesterol absorption in rats.

Five to 20 mg of saponins obtained from alfalfa tops or roots were introduced intragastrically in rats also receiving oral and intravenous ring-labeled cholesterol. The saponins were tested before and after partial acid hydrolysis. Absorption of cholesterol was determined by estimation of fecal sterols and by a dual isotope technique involving assay of plasma radioactivity. Alfalfa top saponins (nonhydrolyzed) reduced absorption of cholesterol. Acid hydrolysis of alfalfa top or root saponins enhanced their ability to inhibit cholesterol absorption.

Mononeuropathy multiplex as a complication of amphetamine angiitis.

A patient who abused multiple drugs developed a rapidly progressive mononeuropathy multiplex, which appeared to respond to corticosteroid therapy with partial resolution. Intravenous methamphetamine had been used almost exclusively from the fourth month prior to the onset of symptoms. Biopsy material revealed a necrotizing angiitis involving medium and small sized arteries, capillaries, and venules, typical of a hypersensitivity-type angiopathy, rather than the previously reported polyarteritis nodosa-type lesions secondary to illicit drugs. The apparent response to corticosteroids suggests that these agents might be useful in the treatment of some complications of drug abuse.

Computerized transaxial tomography in the evaluation of patients with focal epilepsy.

Computerized transaxial tomography was carried out on 50 consecutive unselected patients referred to a neurologic practice for evaluation of focal epilepsy. Structural abnormalities were defined in 35.3 percent of these studies: porencephalic cysts in six patients, diffuse cerebral atrophy in five, cerebral hemiatrophy in three, focal cortical atrophy in two, neoplasms in two, hydrocephalus in one patient, and cerebeller hypoplasia in one. Computerized transaxial tomography is a useful outpatient procedure for evaluation and follow-up of patients with focal seizure disorders.

Alfalfa saponins and alfalfa seeds. Dietary effects in cholesterol-fed rabbits.

Since alfalfa meal prevents hypercholesterolemia and atherosclerosis in rabbits and alfalfa saponins prevent the expected rise in cholesterolemia induced by dietary cholesterol in monkeys, the experiments being reported here were performed to determine whether alfalfa saponins affect atherogenesis in rabbits. In addition, the effects of alfalfa seeds were studied. Cholesterol-feb rabbits were randomly assigned to 3 groups: (a) control animals (N = 18); (b) animals maintained on a diet containing 1.0 to 1.2% alfalfa saponins (N = 18); and (c) animals maintained on a diet containing 40% alfalfa seeds (N = 17). Results after a 4-month observation period demonstrated that alfalfa saponins and alfalfa seeds reduce hypercholesterolemia, aortic sudanophilia, and the concentration of cholesterol in aortic intima-plus-media and in the liver, but do not induce changes in the hematocrit.

Cryptococcal meningitis in pregnancy.

Cryptococcal meningitis was diagnosed in a pregnant woman at 21 weeks' gestation. The availability of fetal tissues, blood, and amniotic fluid in such a patient receiving therapy with amphotericin B plus flucytosine afforded the opportunity to study the effects of the disease and therapeutic agents on the developing fetus. The amphotericin B concentration in amniotic fluid was 0.25 micrograms/ml and that of flucytosine was 168 micrograms/ml. The concentrations in cord blood were 0.3 micrograms/ml and 64.7 micrograms/ml, respectively. No evidence was found of amphotericin B or flucytosine toxicity in fetal tissues, although exposure of the fetus to these compounds was of brief duration.