Physiology of magnesium metabolism and the use of magnesium in intensive care (literature review with the results of own observations, part 1)

The first part of the review presents data on the content of magnesium in organs and tissues of the human body, the role of magnesium in the implementation of multiple functions, and the peculiarities of its intake and excretion from the body. A significant part of the review is devoted to methods for determining the concentration of magnesium in biological fluids of the human body. The advantages, disadvantages and limitations of various methods are presented. The most common methods for studying the concentration of magnesium in biological fluids of the body, which are used in clinical medicine all over the world, are photometric methods with dyes. The role of the fraction of ionized magnesium in the body, the content of which is determined electrochemically, is still uncertain. Cellular magnesium studies are extremely complex and time-consuming. Cells of different organs and tissues normally contain very different amounts of magnesium. It is not possible to judge about the presence of magnesium deficiency in the body by its concentration in plasma or serum. To detect a decrease in the tissue content of magnesium, tests with magnesium load and the subsequent observation of the rate of its excretion from the body are used. The causes for the development of hypomagnesemia are extremely numerous. The main of them are: any severe stress, restriction of magnesium intake into the body, an increase in its losses through the gastrointestinal tract and the kidneys in various pathological conditions. The formation of hypomagnesemia is facilitated by therapy with numerous medications, which are very widely used in clinical practice, and especially in the intensive care. Studies on the distribution of magnesium in the body after its intravenous administration have shown that, despite the large size of hydrated magnesium ions, they can not only paradoxically quickly spread in the extracellular water space, but most likely are also able to quickly penetrate through cell membranes, spreading in the intracellular water compartment.

Assessment of multiple boiling of potable water utilizing household kettles for consumption

Boiling potable water utilizing 11 household/office electrical kettles for sterilization and aesthetic purposes is common among all age groups. However, the effect of continued boiling of the same water multiple times utilizing household electrical kettles on potable water quality has not been investigated previously; thus, the current study experimentally investigates the effect of reboiling potable water seven times on potable water quality. Kettle H (Dexon) recorded the highest concentration increase in Cl− and of 62.5 and 104%, respectively. In the case of cations, kettles I (Dexon Glass) and H (Dexon) recorded the highest concentration values for Na+ (48.8 ppm) ion in comparison with Ca2+ (31.8 ppm; kettle K (Moulinex)) and Mg2+ (5.8 ppm; kettles I and H). Kettles A (Sharp) and E (Black + Decker) showed a total dissolved solids (TDS) value of 34 ppm and a pH value of 9.05, respectively, after the second boiling that is undesirable as per the permissible standards. It is observed that kettles with a water compartment made of stainless steel displayed values closer to the raw sample after one to two boiling as per anions, pH and TDS analyses. Moulinex, Tokyo, Wansa and Bosch showed the best results in the case of various analyses.

Amidinoquinoxaline-Based Nitrones as Lipophilic Antioxidants

The potential of nitrones (N-oxides) as therapeutic antioxidants is due to their ability to counteract oxidative stress, mainly attributed to their action as radical scavengers toward C- and O-centered radicals. Among them, nitrones from the amidinoquinoxaline series resulted in interesting derivatives, due to the ease with which it is possible to introduce proper substituents within their structure in order to modulate their lipophilicity. The goal is to obtain lipophilic antioxidants that are able to interact with cell membranes and, at the same time, enough hydrophilic to neutralize those radicals present in a water compartment. In this work, the antioxidant efficacy of a series of amidinoquinoxaline nitrones has been evaluated regarding the oxidation of 2-deoxyribose and lipid peroxidation. The results have been rationalized on the basis of the different possible mechanisms involved, depending on some of their properties, such as lipophilicity, the ability to scavenge free radicals, and to undergo single electron transfer (SET) reactions.

Mobilization of bacteriophages from soil matrix to soil water in the Attert River basin: A case study

<p>Bacteriophages are numerous, tremendously diverse and ubiquitous in the environment. Since the 1960s, bacteriophages have been proposed as new tracers to investigate the hydrological processes in addition to conventional tracers (i.e. isotopes, salts, dyes). Their dynamic into water (i.e. surface water, groundwater) have been well studied. However, the soil compartment known for its important microbial activity, have been few characterized in terms of bacteriophage diversity. Hence, in the present study, the objective is to investigate the transport of soil viral population from the soil matrix to the soil water compartment. This mobilization from the soil matrix is mainly driven by the adsorption/desorption mechanisms to which bacteriophages are subjected. Therefore, in order to understand the dynamics of the bacteriophage population, both soil and soil water were sampled from the Weierbach forest, located in the Attert River basin (Grand-Duchy of Luxembourg) at the topsoil level (i.e. 0-20 cm) over a period of one month. Due to a lower abundance of the microbial population in soil water, an enrichment method was carried out to increase the concentration. Subsequently, a shotgun metagenomics analysis was performed on the soil and soil water samples to obtain the DNA sequences, which were then sorted using bioinformatics and statistical analyses, allowing ultimately the identification of the viral populations. The moving of the bacteriophage populations from the soil to the soil water provides information on their transport capacity, in particular by taking into account environmental conditions such as air and soil temperatures, precipitation, soil humidity, soil pH, etc.  </p><p> </p><p><strong>Key words</strong>: bacteriophages, soil, water, transport, environmental conditions</p>

Standard MRI-based attenuation correction for PET/MRI phantoms: a novel concept using MRI-visible polymer

Background PET/MRI phantom studies are challenged by the need of phantom-specific attenuation templates to account for attenuation properties of the phantom material. We present a PET/MRI phantom built from MRI-visible material for which attenuation correction (AC) can be performed using the standard MRI-based AC. Methods A water-fillable phantom was 3D-printed with a commercially available MRI-visible polymer. The phantom had a cylindrical shape and the fillable compartment consisted of a homogeneous region and a region containing solid rods of different diameters. The phantom was filled with a solution of water and [18F]FDG. A 30 min PET/MRI acquisition including the standard Dixon-based MR-AC method was performed. In addition, a CT scan of the phantom was acquired on a PET/CT system. From the Dixon in-phase, opposed-phase and fat images, a phantom-specific AC map (Phantom MR-AC) was produced by separating the phantom material from the water compartment using a thresholding-based method and assigning fixed attenuation coefficients to the individual compartments. The PET data was reconstructed using the Phantom MR-AC, the original Dixon MR-AC, and an MR-AC just containing the water compartment (NoWall-AC) to estimate the error of ignoring the phantom walls. CT-based AC was employed as the reference standard. Average %-differences in measured activity between the CT corrected PET and the PET corrected with the other AC methods were calculated. Results The phantom housing and the liquid compartment were both visible and distinguishable from each other in the Dixon images and allowed the segmentation of a phantom-specific MR-based AC. Compared to the CT-AC PET, average differences in measured activity in the whole water compartment in the phantom of −0.3%, 9.4%, and −24.1% were found for Dixon phantom MR-AC, MR-AC, and NoWall-AC based PET, respectively. Average differences near the phantom wall in the homogeneous region were −0.3%, 6.6%, and −34.3%, respectively. Around the rods, activity differed from the CT-AC PET by 0.7%, 8.9%, and −45.5%, respectively. Conclusion The presented phantom material is visible using standard MR sequences, and thus, supports the use of standard, phantom-independent MR measurements for MR-AC in PET/MRI phantom studies.

Monitoring of contaminated areas: Environmental Health Surveillance actions in Diadema/SP Brazil

Contaminated areas are a challenge for public health, since the most diverse chemicals can interfere with human health, making it necessary to adopt health promotion measures, prevention and control of diseases and diseases. That way this work aims to disseminate the actions carried out by the Environmental Health Surveillance of the city of Diadema to monitor the contaminated areas, aiming at reducing the risk to the population's health. For this purpose, it was carried out the characterization of the environment of the contaminated areas using Mapinfo software and tools free of georeferencing, recording of information from research in information and dissemination systems for institutions, services and municipal authorities. As a result, it can be highlighted that 100% of the areas were characterized with definitive radius of surroundings based on the affected environmental compartment; 88,63% were registered in the Health Surveillance Information System for Populations exposed to contaminated soil (SISSOLO). In 27.3% of the areas deep wells were found and out of these, 83.30% they made the buffering/deactivation and 16.7% use the water for industrial purposes. Of the identified wells around 54,5% were buffered/deactivated and 18,2% are under monitoring. It is concluded that it is essential to continuously monitor the territory through different strategies, seeking technical support, invest in intra- and intersectoral articulation and define work processes in order to detect changes in the determinants and constraints of the environment that interfere with human health and thus be able to act in the best possible way. Additionally, it was found that mapping prior to field work is essential to qualify the information and that including the investigation of the water compartment is important to identify and interrupt exposure routes so present in daily life. Key messages It is concluded that it is essential to continuously monitor the territory through different strategies, seeking technical support, invest in intra- and intersectoral articulation. It was found that mapping prior to field work is essential to qualify the information and that including the investigation of the water compartment is important to interrupt exposure routes.

Harmonization of diffusion MRI datasets with adaptive dictionary learning

Diffusion magnetic resonance imaging can indirectly infer the microstructure of tissues and provide metrics subject to normal variability in a population. Potentially abnormal values may yield essential information to support analysis of controls and patients cohorts, but subtle confounds could be mistaken for purely biologically driven variations amongst subjects. In this work, we propose a new harmonization algorithm based on adaptive dictionary learning to mitigate the unwanted variability caused by different scanner hardware while preserving the natural biological variability of the data. Our harmonization algorithm does not require paired training datasets, nor spatial registration or matching spatial resolution. Overcomplete dictionaries are learned iteratively from all datasets at the same time with an adaptive regularization criterion. removing variability attributable to the scanners in the process. The obtained mapping is applied directly in the native space of each subject towards a scanner-space. The method is evaluated with a public database which consists of two different protocols acquired on three different scanners. Results show that the effect size of the four studied diffusion metrics is preserved while removing variability attributable to the scanner. Experiments with alterations using a free water compartment, which is not simulated in the training data, shows that the modifications applied to the diffusion weighted images are preserved in the diffusion metrics after harmonization, while still reducing global variability at the same time. The algorithm could help multicenter studies pooling their data by removing scanner specific confounds, and increase statistical power in the process.