Organization of aerobactin, hemolysin, and antibacterial resistance genes in lactose negative Escherichia coli strains of serotype O4 isolated from children with dhiarrea

Epidemiologically related, non-lactose-fermenting (NLF) Escherichia coli strains of serotype O4 have been isolated at a high frequency from children with diarrhea in Somalia (M. Nicoletti, F. Superti, C. Conti, A. Calconi, and C. Zagaglia, J. Clin. Microbiol. 26:524-529, 1988). In order to define the virulence potential of these strains, we characterized the replication properties of their high-molecular-weight plasmids and studied the genetic locations and organization of the aerobactin (aer) and hemolysin (hly) determinants encoded by 23 NLF O4 E. coli strains. Southern blot hybridizations, mobilization assays of nonconjugative plasmids, and incompatibility-exclusion experiments conducted with a conjugative incompatibility group FI (IncFI) plasmid showed that (i) 20 out of the 23 strains examined harbor a 160- to 180-kb IncFI plasmid that shares homology with the basic replicons RepFIA, RepFIB, and (except for the plasmid of one strain) RepFIC, and 22 strains also contain a 40- to 140-kb IncFII plasmid sharing homology with the RepFIIA replicon; (ii) the IncFI plasmid is nonconjugative and carries antibiotic resistance genes; (iii) the aer system is located on the IncFI plasmids and/or the chromosomes in the three strains not harboring IncFI, and it is found in an inverted orientation; (iv) the hly determinants are located on the chromosome, and their genetic organization is well conserved and closely resembles that of the reference hemolytic plasmid pHly152; and (v) Hly- mutants obtained by transposon insertion mutagenesis are not cytotoxic to HeLa cell monolayers, indicating that hemolysin is responsible for the high cytotoxic activity we have previously reported for these strains. The structural organization of the plasmid-encoded aer operon, together with the finding that those plasmids also carry antibiotic resistance genes, indicates that the IncFI plasmid of the NLF O4 E. coli strains studied more closely resembles aer-encoding virulence IncFI Salmonella R plasmids than E. coli ColV plasmids. The data presented here cannot rule out whether the strains examined are potentially intestinal or extraintestinal pathogens. Nevertheless, the genetic organization of the virulence genes, together with the epidemiological behavior and the wide spectrum of antibiotic resistance of the NLF O4 E. coli strains, indicates that these strains are structured as typical E. coli pathogenic isolates of human origin

Monitoring prohemostatic treatment in bleeding patients

Acutely bleeding patients are commonly found in the trauma and major surgery scenarios. They require prompt and effective treatment to restore an adequate hemostatic pattern, to avoid serious and sometimes life-threatening complications.Different prohemostatic treatments are available, including allogeneic blood derivatives (fresh frozen plasma, platelet concentrates, and cryoprecipitates), prothrombin complex concentrates, specific coagulation factors (fibrinogen, recombinant factor XIII, recombinant activated factor VII), and drugs (protamine for patients under heparin treatment, desmopressin, antifibrinolytics).For decades, prohemostatic treatment of the acutely bleeding patient was based on empirical strategies and clinical judgment, both in terms of a correct diagnosis of the mechanism(s) leading to bleeding, and of an assessment of the effects of the treatment. This empirical strategy may lead to excessive or unnecessary use of allogeneic blood products, as well as to an incorrect, inefficacious, or even dangerous treatment. Different monitoring devices are nowadays available for guiding the diagnostic and therapeutic decision-making process in an acutely bleeding patient. This review addresses the available tools for monitoring prohemostatic treatment of the bleeding patient, with a specific respect for point-of-care tests (thromboelastography, thromboelastometry, platelet function tests, and heparin monitoring systems) at the light of the existing evidence

PULSE-SHAPE DISCRIMINATION OF LIQUID SCINTILLATORS

In this paper we describe the results of different techniques applied to characterize experimentally the pulse shape discrimination capability of liquid scintillators. A detailed comparison of the results obtained with each method is reported, together with the description of an optimization strategy which can be adopted to obtain the best exploitation of the intrinsic PSD feature of the scintillator samples

Effect of preoperative P2Y12 and thrombin platelet receptor inhibition on bleeding after cardiac surgery

BACKGROUND: Drugs that act on the platelet P2Y12 receptor are responsible for postoperative bleeding in cardiac surgery. However, protease-activated receptor (PAR) that reacts to thrombin stimulation might still be active in patients treated with P2Y12 inhibitors. Preoperative platelet function testing could possibly guide the timing of surgery. We investigated the association between P2Y12 receptor and PAR inhibition and bleeding after cardiac surgery. METHODS: A retrospective cohort study of 361 patients undergoing cardiac surgery and treated with P2Y12 anti-platelet agents was undertaken. All patients received a preoperative multiplate electrode aggregometry testing of platelet P2Y12 receptor activity (ADPtest) and PAR reactivity with thrombin receptor-activating peptide (TRAP) stimulation. ADPtest and TRAPtest data measured before surgery were analysed for association with postoperative bleeding (ml per 12 h) and severe postoperative bleeding. RESULTS: Both the ADPtest and the TRAPtest were significantly (P=0.001) associated with postoperative bleeding. A threshold of 22 U for the ADPtest yielded a negative predictive value (NPV) of 94% and a positive predictive value (PPV) of 20%, and a threshold of 75 U for the TRAPtest yielded an NPV of 95% and a PPV of 23%. In the subgroup of patients with ADPtest <22 U, TRAPtest ≥75 U was not associated with severe bleeding (NPV of 100% and PPV of 37%). CONCLUSIONS: In patients taking P2Y12 receptor inhibitors, residual platelet reactivity to thrombin stimulation limits the risk of severe postoperative bleeding

You're the Coach: A Guide for Parents of New Drivers, December 8, 2015

This publication is a guide for parents and guardians of teenagers learning to drive. It should be used with the Iowa Driver’s Manual to aid you in instructing your new driver about how to safely and responsibly operate a motor vehicle. Since the task of driving is affected by changing conditions, this manual does not attempt to cover all situations that may arise

The successful introduction of an adapted form of the mini extra corporeal circulation used for cardiac surgery in an obese patient

Obese patients undergoing cardiac surgery have been shown to have a high risk of developing postoperative complications, specifically: increased length of hospital stay, readmission to intensive care unit, acute renal failure, deep sternal wound infections and new onset of atrial fibrillation

Highlight on the Mechanism of Linear Polyamidoamine Degradation in Water

This paper aims at elucidating the degradation mechanism of linear polyamidoamines (PAAs) in water. PAAs are synthesized by the aza-Michael polyaddition of prim-monoamines or bis-sec-amines with bisacrylamides. Many PAAs are water-soluble and warrant potential for biotechnological applications and as flame-retardants. PAAs have long been known to degrade in water at pH 65 7, but their degradation mechanism was never explored in detail. Filling this gap was necessary to assess the suitability of PAAs for the above applications. To this aim, a small library of nine PAAs was expressly synthesized and their degradation mechanism in aqueous solution studied by 1H-NMR in different conditions of pH and temperature. The main degradation mechanism was in all cases the retro-aza-Michael reaction triggered by dilution but, in some cases, hints were detected of concurrent hydrolytic degradation. Most PAAs were stable at pH 4.0; all degraded at pH 7.0 and 9.0. Initially, the degradation rate was faster at pH 9.0 than at pH 7.0, but the percent degradation after 97 days was mostly lower. In most cases, at pH 7.0 the degradation followed first order kinetics. The degradation rates mainly depended on the basicity of the amine monomers. More basic amines acted as better leaving groups

Sericin-based resins from silk degumming wastewater for the removal of heavy metal ions from water

Chromium (VI) is a water pollutant categorized as \u2018likely to be a carcinogen to humans\u2019 compound when orally ingested with estimated cancer potency 0.5 mg/kg/day. The European Directive 2001/59/EC poses a 5 \ub5g/L threshold concentration for Cr(VI) in groundwaters. In this work, a chemical process was devised to obtain heavy metal ion absorbing resins by the polyaddition of bisacrylamides and 1,2-diaminoethane with sericin using as reaction solvent raw waste-water from silk degumming processes. Silk sericin (SS) is a natural globural protein deriving from silk worm Bombyx mori with molecular weight ranging from 10000 to 300000. Following the alkaline degumming process, sericin is degraded to peptides with molecular weight 20000. These peptides contain lysine-deriving residues that participate in the polyaddition leaving to a resin. This resin is a hybrid one in which a substantial portion is constituted by sericin peptides. The rationale of this approach is that the guanidinum ion has the ability to strongly bind oxoanions, due to its geometrical Y-shaped, planar orientation, optimizing charge distribution and hydrogen bonds [1]. SS resins were evaluated for the removal of both positively charged (Cu2+, Co2+, Ni2+, Mn2+) and negatively charged heavy metals oxoanions (CrO42-) from water. Different resins were obtained containing different amounts of sericin. These resins were characterized by elemental analysis and their structure confirmed by FT-IR/ATR spectroscopy. The swelling capacity of the new absorbents in different media and their thermal stability by DSC and TGA techniques were evaluated. The removal properties of resins towards Cu2+, Co2+, Ni2+, Mn2+ and CrO42- ions in aqueous single metal dilute and concentrate solutions were performed in batch absorption experiments and evaluated by EDTA titration in the case of Cu2+, Co2+, Ni2+, Mn2+, and by the UV-VIS spectroscopy in the case of CrO42-. The products showed different absorption capacities depending on the SS content in the resin. Treatment with 0.1 M HCl showed excellent regeneration with maintenance of the resins absorption capacity for 20 regeneration cycles. In conclusion, sericin-based resins, besides being biocompatible, were endowed with environmental friendly preparation process; biodegradability; moderate cost; ability to fast and quantitatively absorb from aqueous solutions even at low pollutant concentration; full reversibility of the absorption process making it economically convenient both for regeneration and metal recovery