Filter-Based Assay for Escherichia coli in Aqueous Samples Using Bacteriophage-Based Amplification

This paper describes a method to detect the presence of bacteria in aqueous samples, based on the capture of bacteria on a syringe filter, and the infection of targeted bacterial species with a bacteriophage (phage). The use of phage as a reagent provides two opportunities for signal amplification: i) the replication of phage inside a live bacterial host (1000-fold amplification for M13 phage in E. coli K12), and ii) the rapid conversion of a colorless substrate to a colored or fluorescent product by an enzyme that is co-expressed with the phage (in this demonstration β- galactosidase, which has a turnover rate of ~ 600 molecules/second). This method can detect a single colony-forming unit (CFU) of E. coli in one liter of water with an overnight culture-based assay, or 50 CFUs of E. coli in 1 liter of water (or 10 mL of orange juice, or 10 mL of skim milk) in less than four hours with a solution-based assay with visual readout. The solution-based assay does not require specialized equipment or access to a laboratory, and is more rapid than existing tests that are suitable for use at the point of access. This method could be applied to the detection of many different bacteria, in parallel, with bacteriophages that express enzymes not natively expressed in the target bacteria.Chemistry and Chemical Biolog

Rapidly progressive glomerulonephritis in a child with Henoch-Schönlein Vasculitis and familial Mediterranean fever

Henoch-Schonlein Vasculitis (HSV) is systemic small vessel vasculitis involving the skin, kidney, joints, and gastrointestinal tract. The proportion of patients reported to have renal involvement varies between 20% and 80%. Rapidly progressive glomerulonephritis (RPGN)is rare syndrome in children, characterized by clinical features of glomerulonephritis (GN) and rapid loss of renal function. We present a severe kidney involvement in a 14 year old boy with HSV in who is carring MEFV mutation. A 14 year old boy had developed sudden onset of palpable purpuric rash on his extensor surfaces of lower extremities. He had elevated an erythrocyte sedimentation rate (ESR) (45 mm/h), C-reactive protein (3.74 mg/dl), serum urea 66 mg/dl, serum creatinine 1.8 mg/dl. Also, he had hypocomplementemia. Antinuclear antibody, anti ds DNA, antineutrophil cytoplasmic antibody, anticardiolipine antibodies were negative. Urinalysis revealed macroscopic hematuria and proteinuria with a 24-h urinary protein excretion of 55 mg/m2/h. The renal biopsy specimen showed crescentic and necrotizing glomerulonephritis. He had also M694V/E148Q compound heterozygote mutation. Clinical symptoms and renal failure resolved with intermittant hemodialysis and medical therapy

Mouse model of carbon tetrachloride induced liver fibrosis: Histopathological changes and expression of CD133 and epidermal growth factor

<p>Abstract</p> <p>Background</p> <p>In the setting of chronic liver injury in humans, epidermal growth factor (EGF) and EGF receptor (EGFR) are up-regulated and have been proposed to have vital roles in both liver regeneration and development of hepatocellular carcinoma (HCC). Chronic liver injury also leads to hepatic stellate cell (HSC) differentiation and a novel subpopulation of HSCs which express CD133 and exhibit properties of progenitor cells has been described in rats. The carbon tetrachloride (CCl₄)-induced mouse model has been historically relied upon to study liver injury and regeneration. We exposed mice to CCl₄to assess whether EGF and CD133+ HSCs are up-regulated in chronically injured liver.</p> <p>Methods</p> <p>CCl₄in olive oil was administered to strain A/J mice three times per week by oral gavage.</p> <p>Results</p> <p>Multiple well-differentiated HCCs were found in all livers after 15 weeks of CCl₄treatment. Notably, HCCs developed within the setting of fibrosis and not cirrhosis. CD133 was dramatically up-regulated after CCl₄treatment, and increased expression of desmin and glial fibrillary acidic protein, representative markers of HSCs, was also observed. EGF expression significantly decreased, contrary to observations in humans, whereas the expression of amphiregulin, another EGFR ligand, was significantly increased.</p> <p>Conclusions</p> <p>Species-specific differences exist with respect to the histopathological and molecular pathogenesis of chronic liver disease. CCl₄-induced chronic liver injury in A/J mice has important differences compared to human cirrhosis leading to HCC.</p

Perspectives on care and communication involving incurably ill Turkish and Moroccan patients, relatives and professionals: a systematic literature review

<p>Abstract</p> <p>Background</p> <p>Our aim was to obtain a clearer picture of the relevant care experiences and care perceptions of incurably ill Turkish and Moroccan patients, their relatives and professional care providers, as well as of communication and decision-making patterns at the end of life. The ultimate objective is to improve palliative care for Turkish and Moroccan immigrants in the Netherlands, by taking account of socio-cultural factors in the guidelines for palliative care.</p> <p>Methods</p> <p>A systematic literature review was undertaken. The data sources were seventeen national and international literature databases, four Dutch journals dedicated to palliative care and 37 websites of relevant national and international organizations. All the references found were checked to see whether they met the structured inclusion criteria. Inclusion was limited to publications dealing with primary empirical research on the relationship between socio-cultural factors and the health or care situation of Turkish or Moroccan patients with an oncological or incurable disease. The selection was made by first reading the titles and abstracts and subsequently the full texts. The process of deciding which studies to include was carried out by two reviewers independently. A generic appraisal instrument was applied to assess the methodological quality.</p> <p>Results</p> <p>Fifty-seven studies were found that reported findings for the countries of origin (mainly Turkey) and the immigrant host countries (mainly the Netherlands). The central themes were experiences and perceptions of family care, professional care, end-of-life care and communication. Family care is considered a duty, even when such care becomes a severe burden for the main female family caregiver in particular. Professional hospital care is preferred by many of the patients and relatives because they are looking for a cure and security. End-of-life care is strongly influenced by the continuing hope for recovery. Relatives are often quite influential in end-of-life decisions, such as the decision to withdraw or withhold treatments. The diagnosis, prognosis and end-of-life decisions are seldom discussed with the patient, and communication about pain and mental problems is often limited. Language barriers and the dominance of the family may exacerbate communication problems.</p> <p>Conclusions</p> <p>This review confirms the view that family members of patients with a Turkish or Moroccan background have a central role in care, communication and decision making at the end of life. This, in combination with their continuing hope for the patient’s recovery may inhibit open communication between patients, relatives and professionals as partners in palliative care. This implies that organizations and professionals involved in palliative care should take patients’ socio-cultural characteristics into account and incorporate cultural sensitivity into care standards and care practices<it>.</it></p

An international collaborative evaluation of central serous chorioretinopathy: different therapeutic approaches and review of literature. The European Vitreoretinal Society central serous chorioretinopathy study

Purpose: To study and compare the efficacy of different therapeutic options for the treatment of central serous chorioretinopathy (CSCR). Methods: This is a nonrandomized, international multicentre study on 1719 patients (1861 eyes) diagnosed with CSCR, from 63 centres (24 countries). Reported data included different methods of treatment and both results of diagnostic examinations [fluorescein angiography and/or optical coherent tomography (OCT)] and best-corrected visual acuity (BCVA) before and after therapy. The duration of observation had a mean of 11&nbsp;months but was extended in a minority of cases up to 7&nbsp;years. The aim of this study is to evaluate the efficacy of the different therapeutic options of CSCR in terms of both visual (BCVA) and anatomic (OCT) improvement. Results: One thousand seven hundred nineteen patients (1861 eyes) diagnosed with CSCR were included. Treatments performed were nonsteroidal anti-inflammatory eye drops, laser photocoagulation, micropulse diode laser photocoagulation, photodynamic therapy (PDT; Standard PDT, Reduced-dose PDT, Reduced-fluence PDT), intravitreal (IVT) antivascular endothelial growth factor injection (VEGF), observation and other treatments. The list of the OTHERS included both combinations of the main proposed treatments or a variety of other treatments such as eplerenone, spironolactone, acetazolamide, beta-blockers, anti-anxiety drugs, aspirin, folic acid, methotrexate, statins, vitis vinifera extract medication and pars plana vitrectomy. The majority of the patients were men with a prevalence of 77%. The odds ratio (OR) showed a partial or complete resolution of fluid on OCT with any treatment as compared with observation. In univariate analysis, the anatomical result (improvement in subretinal fluid using OCT at 1&nbsp;month) was favoured by age &lt;60&nbsp;years (p&nbsp;&lt;&nbsp;0.005), no previous observation (p&nbsp;&lt;&nbsp;0.0002), duration less than 3&nbsp;months (p&nbsp;&lt;&nbsp;0.0001), absence of CSCR in the fellow eye (p&nbsp;=&nbsp;0.04), leakage outside of the arcade (p&nbsp;=&nbsp;0.05) and fluid height &gt;500&nbsp;\u3bcm (p&nbsp;=&nbsp;0.03). The OR for obtaining partial or complete resolution showed that anti-VEGF and eyedrops were not statistically significant; whereas PDT (8.5), thermal laser (11.3) and micropulse laser (8.9) lead to better anatomical results with less variability. In univariate analysis, the functional result at 1&nbsp;month was favoured by first episode (p&nbsp;=&nbsp;0.04), height of subretinal fluid &gt;500&nbsp;\u3bcm (p&nbsp;&lt;&nbsp;0.0001) and short duration of observation (p&nbsp;=&nbsp;0.02). Finally, there was no statistically significant difference among the treatments at 12&nbsp;months. Conclusion: Spontaneous resolution has been described in a high percentage of patients. Laser (micropulse and thermal) and PDT seem to lead to significant early anatomical improvement; however, there is little change beyond the first month of treatment. The real visual benefit needs further clarification

Determination of Complete Melting and Surface Premelting Points of Silver Nanoparticles by Molecular Dynamics Simulation

A molecular dynamics simulation based on the embedded-atom method was conducted at different sizes of single-crystal Ag nanoparticles (NPs) with diameters of 4 to 20 nm to find complete melting and surface premelting points. Unlike the previous theoretical models, our model can predict both complete melting and surface premelting points for a wider size range of NPs. Programmed heating at an equal rate was applied to all sizes of NPs. Melting kinetics showed three different trends that are, respectively, associated with NPs in the size ranges of 4 to 7 rim, 8 to 10 nm, and 12 to 20 nm. NPs in the first range melted at a single temperature without passing through a surface premelting stage. Melting of the second range started by forming a quasi-liquid layer that expanded to the core, followed by the formation of a liquid layer of 1.8 nm thickness that also subsequently expanded to the core with increasing temperature and completed the melting process. For particles in the third range, the 1.8 nm liquid layer was formed once the thickness of the quasi-liquid layer reached S rim. The liquid layer expanded to the core and formed thicker stable liquid layers as the temperature increased toward the complete melting point. The ratio of the quasi-liquid layer thickness to the NP radius showed a linear relationship with temperature.&nbsp;A molecular dynamics simulation based on the embedded-atom method was conducted at different sizes of single-crystal Ag nanoparticles (NPs) with diameters of 4 to 20 nm to find complete melting and surface premelting points. Unlike the previous theoretical models, our model can predict both complete melting and surface premelting points for a wider size range of NPs. Programmed heating at an equal rate was applied to all sizes of NPs. Melting kinetics showed three different trends that are, respectively, associated with NPs in the size ranges of 4 to 7 rim, 8 to 10 nm, and 12 to 20 nm. NPs in the first range melted at a single temperature without passing through a surface premelting stage. Melting of the second range started by forming a quasi-liquid layer that expanded to the core, followed by the formation of a liquid layer of 1.8 nm thickness that also subsequently expanded to the core with increasing temperature and completed the melting process. For particles in the third range, the 1.8 nm liquid layer was formed once the thickness of the quasi-liquid layer reached S rim. The liquid layer expanded to the core and formed thicker stable liquid layers as the temperature increased toward the complete melting point. The ratio of the quasi-liquid layer thickness to the NP radius showed a linear relationship with temperature.</div

Molecular Dynamics Simulation of Sintering and Surface Premelting of Silver Nanoparticles

Sintering of Ag nanoparticles (NPs) is increasingly being used as a driving mechanism for joining in the microelectronics industry. We therefore performed molecular dynamics simulations based on the embedded atom method (EAM) to study pressureless sintering kinetics of two Ag NPs in the size range of (4 to 20 nm), and sintering of three and four Ag NPs of 4 nm diameter. We found that the sintering process passed through three main stages. The first was the neck formation followed by a rapid increase of the neck radius at 50K for 20 nm particles and at 10 K for smaller NPs. The second was characterized by a gradual linear increase of the neck radius to particle radius ratio as the temperature of the sintered structure was increased to the surface premelting point. Different than previous sintering studies, a twin boundary was formed during the second stage that relaxed the sintered structure and decreased the average potential energy (PE). The third stage of sintering was a rapid shrinkage during surface premelting of the sintered structure. Based on pore geometry, densification occurred during the first stage for three 4 nm particles and during the second stage for four 4 nm particles. Sintering rates obtained by our simulation were higher than those obtained by theoretical models generally used for predicting sintering rates of microparticles