Proteomic signatures differentiating Bacillus anthracis Sterne sporulation on soil relative to laboratory media.

The process of sporulation is vital for the stability and infectious cycle of Bacillus anthracis. The spore is the infectious form of the organism and therefore relevant to biodefense. While the morphological and molecular events occurring during sporulation have been well studied, the influence of growth medium and temperature on the proteins expressed in sporulated cultures is not well understood. Understanding the features of B. anthracis sporulation specific to natural vs. laboratory production will address an important question in microbial forensics. In an effort to bridge this knowledge gap, a system for sporulation on two types of agar-immobilized soils was used for comparison to cultures sporulated on two common types of solid laboratory media, and one liquid sporulation medium. The total number of proteins identified as well as their identity differed between samples generated in each medium and growth temperature, demonstrating that sporulation environment significantly impacts the protein content of the spore. In addition, a subset of proteins common in all of the soil-cultivated samples was distinct from the expression profiles in laboratory medium (and vice versa). These differences included proteins involved in thiamine and phosphate metabolism in the sporulated cultures produced on soils with a notable increase in expression of ATP binding cassette (ABC) transporters annotated to be for phosphate and antimicrobial peptides. A distinct set of ABC transporters for amino acids, sugars and oligopeptides were found in cultures produced on laboratory media as well as increases in carbon and amino acid metabolism-related proteins. These protein expression changes indicate that the sporulation environment impacts the protein profiles in specific ways that are reflected in the metabolic and membrane transporter proteins present in sporulated cultures.

3D-printed poly(vinylidene fluoride)/carbon nanotube composites as a tunable, low-cost chemical vapour sensing platform.

We report the production of flexible, highly-conductive poly(vinylidene fluoride) (PVDF) and multi-walled carbon nanotube (MWCNT) composites as filament feedstock for 3D printing. This account further describes, for the first time, fused deposition modelling (FDM) derived 3D-printed objects with chemiresistive properties in response to volatile organic compounds. The typically prohibitive thermal expansion and die swell characteristics of PVDF were minimized by the presence of MWCNTs in the composites enabling straightforward processing and printing. The nanotubes form a dispersed network as characterized by helium ion microscopy, contributing to excellent conductivity (∼3 × 10-2 S cm-1). The printed composites contain little residual metal particulate relative to parts from commercial PLA-nanocomposite material visualized by micro-X-ray computed tomography (µ-CT) and corroborated with thermogravimetric analysis. Printed sensing strips, with MWCNT loadings up to 15% mass, function as reversible vapour sensors with the strongest responses arising with organic compounds capable of readily intercalating and subsequently swelling the PVDF matrix (acetone and ethyl acetate). A direct correlation between MWCNT concentration and resistance change was also observed, with larger responses (up to 161% after 3 minutes) being generated with decreased MWCNT loadings. These findings highlight the utility of FDM printing in generating low-cost sensors that respond strongly and reproducibly to target vapours. Furthermore, the sensors can be easily printed in different geometries, expanding their utility to wearable form factors. The proposed formulation strategy may be tailored to sense diverse sets of vapour classes through structural modification of the polymer backbone and/or functionalization of the nanotubes within the composite.

Structural and spectroscopic studies of a rare non-oxido V(v) complex crystallized from aqueous solution.

A non-oxido V(v) complex with glutaroimide-dioxime (H3L), a ligand for recovering uranium from seawater, was synthesized from aqueous solution as Na[V(L)2]·2H2O, and the structure determined by X-ray diffraction. It is the first non-oxido V(v) complex that has been directly synthesized in and crystallized from aqueous solution. The distorted octahedral structure contains two fully deprotonated ligands (L3-) coordinating to V5+, each in a tridentate mode via the imide N (R V-N = 1.96 Å) and oxime O atoms (R V-O = 1.87-1.90 Å). Using 17O-labelled vanadate as the starting material, concurrent 17O/51V/1H/13C NMR, in conjunction with ESI-MS, unprecedentedly demonstrated the stepwise displacement of the oxido V[double bond, length as m-dash]O bonds by glutaroimide-dioxime and verified the existence of the "bare" V5+/glutaroimide-dioxime complex, [V(L)2]-, in aqueous solution. In addition, the crystal structure of an intermediate 1 : 1 V(v)/glutaroimide-dioxime complex, [VO2(HL)]-, in which the oxido bonds of vanadate are only partially displaced, corroborates the observations by NMR and ESI-MS. Results from this work provide important insights into the strong sorption of vanadium on poly(amidoxime) sorbents in the recovery of uranium from seawater. Also, because vanadium plays important roles in biological systems, the syntheses of the oxido and non-oxido V5+ complexes and the unprecedented demonstration of the displacement of the oxido V[double bond, length as m-dash]O bonds help with the on-going efforts to develop new vanadium compounds that could be of importance in biological applications.

Postoperative complications necessitating right lower lobectomy in a heart-lung transplant recipient with previous sternotomy.

Heart-lung transplantation for treatment of end-stage cardiopulmonary disease continues to be plagued by many problems. Three primary ones are the technical difficulties that can be encountered, particularly in those patients who have undergone previous cardiac operations, the additional restriction on donor availability imposed by the lack of satisfactory preservation techniques, and the need for lung size compatibility. Two of these difficulties and others surfaced postoperatively in a heart-lung transplant recipient who presented a series of unique operative and therapeutic challenges. A 42-year-old woman with chronic pulmonary hypertension and previous atrial septal defect repair underwent a heart-lung transplantation in August 1985. The operative procedure was expectedly complicated by bleeding from extensive mediastinal adhesions from the previous sternotomy and bronchial collateralization. Excessive chest tube drainage postoperatively necessitated reoperation to control bleeding from a right bronchial artery tributary. Phrenic nerve paresis, hepatomegaly, and marked abdominal distention caused persistent atelectasis and eventual right lower lobe collapse. Arteriovenous shunting and low oxygen saturation necessitated right lower lobectomy 15 days after transplantation, believed to be the first use of this procedure in a heart-lung graft recipient. Although oxygenation improved dramatically, continued ventilatory support led to tracheostomy. An intensive, psychologically oriented physical therapy program was initiated to access and retrain intercostal and accessory muscles. The tracheostomy cannula was removed after 43 days and gradual weaning from supplemental oxygen was accomplished. During this protracted recovery period, an episode of rejection was also encountered and successfully managed with steroid therapy. The patient continued to progress satisfactorily and was discharged 83 days after transplantation. She is well and active 20 months after discharge.

The JH/LVOH method in the quantification of aortic regurgitation: how the cardiac sonographer may avoid an important potential pitfall.

Color flow Doppler allows for methods in which to quantitate the severity of valvular regurgitation. In particular, the regurgitant jet height/left ventricular outflow tract height (JH/LVOH) method of quantitating the severity of aortic regurgitation has been validated and is routinely used in the adult echocardiography laboratory. A potential pitfall exists in the measurement of the LVOH. This article points out this potential source of error and, in addition, proposes steps that may be taken by the cardiac sonographer to avoid this potential measurement pitfall.

The evaluation of the abdominal aorta: a "how-to" for cardiac sonographers.

A thorough evaluation of the abdominal aorta can be readily achieved by use of the standard views of the echocardiographic examination. The ultrasound evaluation of the abdominal aorta represents a logical extension of the standard echocardiographic examination of the adult patient. This article provides the information needed to carry out a complete ultrasound examination of the abdominal aorta including the anatomy, the vascular disease, and the steps involved in accomplishing the ultrasound examination of the abdominal aorta.

Symptomatic sinus node dysfunction after heart transplantation.

When donor hearts are studied systematically after transplantation, by programmed electrical stimulation, sinus node dysfunction has been found to be common though data regarding symptoms related to this phenomenon are not available. In this case report we describe a heart transplant recipient who experienced serious symptomatic sinus node dysfunction associated with transient atrial fibrillation 17 days after cardiac transplantation; there was no evidence of donor heart rejection. Intracardiac electrophysiology testing confirmed sinus node dysfunction of the donor heart, but only with relatively rapid atrial pacing rates.

Major determinants of survival and nonsurvival of intraaortic balloon pumping.

The purpose of this study was to find the major determinants of survival and nonsurvival after intraaortic balloon pump (IABP) support. One hundred twenty-nine consecutive patients with IABP support from January 1988 to January 1992 were analyzed retrospectively. Differences between the survival and nonsurvival groups were tested with the Student's t test, chi-squared test, and frequency analysis. The overall survival rate was 50.4% (65 of 129). Nonsurvivors (64 of 129, 49.6%) had higher rates of chronic heart failure (21.9% vs 9.2%, p < 0.05), acute myocardial infarction (53.1% vs 24.6%, p < 0.01), cardiomyopathy (9.4% vs 1.5%, p < 0.05), New York Heart Association functional class IV (51.6% vs 13.9%, p < 0.01), and depressed left ventricular ejection fraction (29.38% +/- 8.99% vs 42.88% +/- 5.24%, mean +/- SD, p < 0.01). The nonsurvival group also had longer duration of cardiopulmonary bypass (115.80 +/- 24.43 vs 78.34 +/- 3.81 min, mean +/- SEM, p < 0.02) and aortic occlusion (57.55 +/- 13.03 vs 41.00 +/- 2.79 min, mean +/- SEM, p < 0.05) than the survival group. The major determinants of death after IABP are acute myocardial infarction, left ventricular ejection fraction < 30%, New York Heart Association functional class IV, and longer duration of cardiopulmonary bypass and aortic occlusion. IABP is effective in sustaining hemodynamics, but severe myocardial pump failure portends a poor treatment outcome.