Ethical Observations on the Choice of Parenteral Solvents

The parenteral administration of insoluble drugs leads to the use of biologically active solvents inducing effects associated with ethical cause of concern including pain and pharmacological interactions. Selected vehicles currently used were ethically and scientifically reviewed. Our investigations allowed reinforcing the formulation decision tree with an ethical point of view. The last generation of cyclodextrin appears to be the safest solvent. Second choice could be lipidic emulsions, third choice being co-solvents, and finally non-ionic surfactants because of their hypersensitivity reactions. Screening tests including pH, osmolality measurements, cytotoxicity, and hemotoxicity, should allow to check the formulation tolerance before the animals' administration.     

The effect of water suppression on the hepatic lipid quantification,as assessed by the LCModel,in a preclinical and clinical scenario

Objective

To investigate the effect of water suppression on the hepatic lipid quantification, using the LCModel.

Materials and methods

MR spectra with and without water suppression were acquired in the liver of mice at 4.7 T and patients at 3 T, and processed with the LCModel. The Cramér–Rao Lower Bound (CRLB) values of the seven lipid resonances were determined to assess the impact of water suppression on hepatic lipid quantification. A paired t test was used for comparison between the CRLBs obtained with and without water suppression.

Results

For the preclinical data, in the high (low) fat fraction subset an overall impairment in hepatic lipid quantification, i.e. an increase of CRLBs (no significant change of CRLBs) was observed in spectra acquired with water suppression. For the clinical data, there were no substantial changes in the CRLB with water suppression. Because (1) the water suppression does not overall improve the quantification of the lipid resonances and (2) the MR spectrum without water suppression is always acquired for fat fraction calculation, the optimal data-acquisition strategy for liver MRS is to acquire only the MR spectrum without water suppression.

Conclusion

For quantification of hepatic lipid resonances, it is advantageous to perform MR spectroscopy without water suppression in a clinical and preclinical scenario (at moderate fields).

     

Pb particles from tap water: bioaccessibility and contribution to child exposure

High particulate lead (Pb) levels can be measured in tap water, but the hazard linked to particulate Pb ingestion is unknown. An in vitro test was developed to determine the bioaccessibility of Pb particles from tap water, based on the Relative Bioaccessibility Leaching Procedure validated for soils, and applied to lab-generated particles and field particles collected behind the aerator tap. Field particles were found in 43% of the 342 taps investigated equipped with an aerator, and contained significant amounts of Pb (0.003-71%, median 4.7%). The bioaccessibility of lab-generated particles ranged from 2 to 96% depending on the particle type (Pb(II) > Brass > Pb(IV) > solder), while that of field particles was distributed between 1.5 and 100% (median 41%). The hazard of particulate Pb ingestion depends on the amount and concentration ingested, and the bioaccessibility of the particulate Pb forms involved. Using the Integrated Exposure Uptake Biokinetic model, the impact of particulate Pb on the exposure of children aged 0.5-7 for the distribution system studied was the most significant when considering a fraction of the exposure from large buildings.     

Proton exchange membrane (PEM) electrolyzer operation under anode liquid and cathode vapor feed configurations

Proton exchange membrane (PEM) electrolysis is a potential alternative technology to crack water in specialty applications where a dry gas stream is needed, such as isotope production. One design proposal is to feed the cathode of the electrolyzer with vapor phase water. This feed configuration would allow isotopic water to be isolated on the cathode side of the electrolyzer and the isotope recovery system could be operated in a closed loop. Tests were performed to characterize the difference in the current–voltage behavior between a PEM electrolyzer operated with a cathode water vapor feed and with an anode liquid water feed. The cathode water vapor feed cell had a maximum limiting current density of 400 mA/cm² at 70 °C compared to a current density of 800 mA/cm² for the anode liquid feed cell at 70 °C. The limiting current densities for the cathode water vapor feed cell were similar to those predicted by a water mass transfer model. It is estimated that a cathode water vapor feed electrolyzer system will need to be between 5 and 8 times larger in active area or number of cells than an anode liquid feed system.     

Changing network support for drinking: Network Support Project 2-year follow-up.

The Network Support Project was designed to determine whether a treatment could lead patients to change their social network from one that supports drinking to one that supports sobriety. This study reports 2-year posttreatment outcomes. Alcohol-dependent men and women (N = 210) were randomly assigned to 1 of 3 outpatient treatment conditions: network support (NS), network support + contingency management (NS + CM), or case management (CaseM, a control condition). Analysis of drinking rates indicated that the NS condition yielded up to 20% more days abstinent than the other conditions at 2 years posttreatment. NS treatment also resulted in greater increases at 15 months in social network support for abstinence, as well as in AA attendance and AA involvement than did the other conditions. Latent growth modeling suggested that social network changes were accompanied by increases in self-efficacy and coping that were strongly predictive of long-term drinking outcomes. The findings indicate that a network support treatment can effect long-term adaptive changes in drinkers' social networks and that these changes contribute to improved drinking outcomes in the long term. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Constraint-Based Approach to Assigning System Components to Tasks

In multi-component systems, individual components must be assigned to the tasks that they are to perform. In many applications, there are several possible task decompositions that could be used to achieve the task, and there are limited resources available throughout the system. We present a technique for making task assignments under these conditions. Constraint satisfaction is used to assign components to particular tasks. Heuristics suggest a task decomposition for which an assignment can be found efficiently. We have applied our technique to the problem of task assignment in systems of underwater robots and instrument platforms working together to collect data in the ocean.     

A Single Component Conducting Polymer Hydrogel as a Scaffold for Tissue Engineering

Conducting polymers (CPs) have exciting potential as scaffolds for tissue engineering, typically applied in regenerative medicine applications. In particular, the electrical properties of CPs has been shown to enhance nerve and muscle cell growth and regeneration. Hydrogels are particularly suitable candidates as scaffolds for tissue engineering because of their hydrated nature, their biocompatibility, and their tissue‐like mechanical properties. This study reports the development of the first single component CP hydrogel that is shown to combine both electro‐properties and hydrogel characteristics. Poly(3‐thiopheneacetic acid) hydrogels were fabricated by covalently crosslinking the polymer with 1,1′‐carbonyldiimidazole (CDI). Their swelling behavior was assessed and shown to display remarkable swelling capabilities (swelling ratios up to 850%). The mechanical properties of the networks were characterized as a function of the crosslinking density and were found to be comparable to those of muscle tissue. Hydrogels were found to be electroactive and conductive at physiological pH. Fibroblast and myoblast cells cultured on the hydrogel substrates were shown to adhere and proliferate. This is the first time that the potential of a single component CP hydrogel has been demonstrated for cell growth, opening the way for the development of new tissue engineering scaffolds.     

Determination of <Emphasis Type="Italic">Bacillus cereus</Emphasis> Emetic Toxin in Food Products by Means of LC–MS²

Cereulide is the heat-stable toxin produced by certain strains of Bacillus cereus. It is the main virulence factor of emetic B. cereus strains, which causes the emetic food poisoning syndrome, including rare fatal cases of food intoxications. Due to presumably low intoxication doses, a sensitive, specific, and robust technique is needed for its detection. In 2002, a LC–MS method was developed which allowed absolute quantification of cereulide using valinomycin as standard. This study describes the validation, according to the Commission Decision 2002/657/EC, of the LC–MS2 method, a tandem mass spectrometry technique, which guarantees lower detection limit and higher specificity. The LC–MS2 method, calibrated with valinomycin, was validated in rice and tested on various matrices (i.e., red beans, spices, and chili con carne) containing cereulide. The process combines a simple extraction step from the food matrix followed by LC–MS2 analysis and detection by ion trap mass spectrometer. The detection limit for cereulide in rice was 0.5 ng eq/g, which is 20 to 2,500 times lower than currently understood intoxicative doses between 10 and 1.280 ng/g previously reported for cereulide. The validated method was specific, sensitive, repeatable, and reproducible with recoveries ranging from 77% to 101%.