Incidents and complications of totally implanted vascular access devices in children: a prospective study

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Integrated Microanalytical System for Simultaneous Voltammetric Measurements of Free Metal Ion Concentrations in Natural Waters

A complexing gel integrated microelectrode (CGIME) for direct measurements of free metal ion concentrations in natural waters has been developed. It is prepared by the successive deposition of microlayers of a chelating resin, an antifouling agarose gel and Hg on a 100-interconnected Ir-based microelectrode array. The trace metals of interest are in a first step accumulated on the chelating resin in proportion to their free ion concentration in solution, then released in acidic solution and detected simultaneously by using square wave anodic stripping voltammetry (SWASV). The reliability of this sensor for the simultaneous measurement of copper, lead and cadmium has been studied by a series of replicate laboratory tests. The proportionality between the voltammetric peak current intensity and the free metal ion concentrations in solution has been demonstrated by using malonate as a model ligand. Finally, the CGIME sensor was applied to the Cu and Pb free concentration measurement in sea water samples and the results compared to the free metal ion concentrations measured using hollow fiber based permeation liquid membrane (HF-PLM) coupled to inductively coupled plasma mass spectrophotometer (ICP-MS). Comparable concentration values were found for both metals with both techniques allowing to validate the CGIME measurements in complex media

Multi Physical–Chemical profiler for real-time in situ monitoring of trace metal speciation and master variables: Development, validation and field applications

This paper describes the development and the application of a submersible Multi Physical-Chemical profiler (MPCP) for in situ measurements of priority trace metal pollutant speciation and master bio-physicochemical variables. It has been designed using advanced voltammetric microsensors, microprocessor, telemetry and "smart" data acquisition and transfer technology. The MPCP allows simultaneous reliable monitoring, down to 150 m over extended period of time, of several major fractions of Cu(II), Pb(ii), and Cd(II): (i) the free metal ions which are known to be related to biological uptake, (ii) the dynamic metal species which are potentially also available for organisms, (iii) the total extractable metals which represent the reservoir of metal in the test medium, and (iv) the particulate and colloidal species, by subtracting (ii) of (iii), which play important role in transport properties and residence time. In addition, it measures also presure, temperature, pH, oxygen, conductivity, salinity, redox E, turbidity and chlorophyll a. The MPCP can be controlled either by an operator on board, in automatic mode following pre-programmed parameters, or remotely from a land station when connected to a remote controller installed in a buoy profiler or on a platform. A detailed description of the system is given. A summary of the laboratory and on-field tests performed to characterize and validate the MPCP measurements is presented. Finally, examples of attended and remote in situ MPCP monitoring/profiling in estuaries and coastal sea waters are reported. The results indicate that the system is reliable and that in situ simultaneous measurements of the three distinct fractions of trace metals can be achieved down to concentrations at the ppt level using square wave anodic stripping voltammetry (SWASV). They also demonstrated the significant advantages of the MPCP in terms of spatial and temporal resolution of data and thus its usefulness for cost effective, more efficient environmental monitoring and pollution control

Functional Sphere Profiling Reveals the Complexity of Neuroblastoma Tumor-Initiating Cell Model12

Neuroblastoma (NB) is a neural crest-derived childhood tumor characterized by a remarkable phenotypic diversity, ranging from spontaneous regression to fatal metastatic disease. Although the cancer stem cell (CSC) model provides a trail to characterize the cells responsible for tumor onset, the NB tumor-initiating cell (TIC) has not been identified. In this study, the relevance of the CSC model in NB was investigated by taking advantage of typical functional stem cell characteristics. A predictive association was established between self-renewal, as assessed by serial sphere formation, and clinical aggressiveness in primary tumors. Moreover, cell subsets gradually selected during serial sphere culture harbored increased in vivo tumorigenicity, only highlighted in an orthotopic microenvironment. A microarray time course analysis of serial spheres passages from metastatic cells allowed us to specifically “profile” the NB stem cell-like phenotype and to identify CD133, ABC transporter, and WNT and NOTCH genes as spheres markers. On the basis of combined sphere markers expression, at least two distinct tumorigenic cell subpopulations were identified, also shown to preexist in primary NB. However, sphere markers-mediated cell sorting of parental tumor failed to recapitulate the TIC phenotype in the orthotopic model, highlighting the complexity of the CSC model. Our data support the NB stem-like cells as a dynamic and heterogeneous cell population strongly dependent on microenvironmental signals and add novel candidate genes as potential therapeutic targets in the control of high-risk NB

A lower fistula rate in hypospadias surgery.

OBJECTIVE: To determine whether specific steps taken after a critical quality control of our results in hypospadias surgery lead to a decrease in fistula rate. PATIENTS AND METHODS: Retrospective review of prospectively collected data. Between 1994 and 2001, our series of 85 tubularized plate urethroplasties (modified Duplay or Duplay-Snodgrass procedure) had a fistula rate of 25.9%. In 2001, we modified our approach by systematically padding the urethral suture with a layer of vascularized subcutaneous preputial tissue, as described by Snodgrass. Scrotal hypospadias were excluded. Surgical outcome was assessed at 1 and 12months. In both groups, all repairs were performed by or under direct supervision of the senior author (BJM). RESULTS: After 2001, 57 hypospadias repairs were performed in 57 patients aged 8months to 14years (median 1.4years). Fistula occurred in two cases, one of which closed spontaneously within 6months. Our fistula rate had dropped to 3.5%, with a minimum follow up of 12months. CONCLUSION: Covering the urethral suture with a padding flap of vascularized preputial tissue helps avoid fistula formation. Technique modification after critical appraisal of our own series led to a much better outcome in this demanding surgery