Low Concentrations Of Urea Research Articles

Numerical and Experimental Analysis of SNCR Installation Performance in a Power Stoker Boiler

The correct design of effective SNCR (Selective Non-Catalytic Reduction) requires solving several technological challenges. For this purpose, CFD modeling and bench tests were used. This study investigated various parameters affecting the NOx reduction rate in a WR-25 stoker boiler. The first parameter analyzed was the NSR (normalized stoichiometric ratio), with a constant urea concentration of 12.5% in the solution injected into the boiler. CFD modeling indicated that increasing the NSR significantly enhances reduction efficiency, especially between NSR 1 and 2, where the efficiency more than doubles. Bench tests confirmed this trend across all boiler power levels, showing deeper reagent penetration in the chamber at higher NSR levels. However, further doubling of NSR did not yield significant efficiency improvements, likely due to limitations in chemical mixing under reagent excess conditions. Further, it was revealed that NOx reduction efficiency decreases as boiler power increases, probably due to reduced reagent residence time at the required thermodynamic conditions. Additionally, different nozzle tip designs were tested, with multi-hole nozzles (two-hole and three-hole), showing better NOx reduction than single-hole nozzles due to improved reagent distribution. Finally, a lower urea concentration in the reagent (12%) led to better NOx reduction compared to a 32.5% concentration, likely due to improved droplet penetration and mixing with flue gases.

Effect of Seed Priming on Germination, Seedling Emergence and Development of Spring Rice Var. Hardinath-1

Poor germination percentage and non-uniform seedling emergence and establishment are major causes of low rice yield in water-deficit arid ecosystems. A seed priming study with a low concentration of MoP, DAP, urea, vitamin C, ZnSO4, sucrose, NaCl, and hydro priming was conducted to assess the seed germination, seedling emergence, establishment, and seedling growth of the spring rice variety Hardinath-1. The experiment was conducted using a completely randomized design with three replications. Two test sets of experiments were carried out using blotting paper rolls and separate sand trays. Germination was observed at intervals of 24 hours up to 7 days, and germination and growth parameters were monitored. The results showed that germination (88.67%) and seedling emergence (88.67%) were high in vitamin C at 7 days after sowing (DAS). Germination energy (81%), germination speed (91.78%), and vigor index (91.78) were higher with seed priming of MoP. The lowest germination (56.44%) was observed with the priming of urea. At 30 DAS, the longest shoot length (19.93 cm) and longest root length (11.79 cm) were observed with the priming of ZnSO4. The highest seedling fresh weight (0.75 g) and dry weight (0.16 g), the highest number of leaves (3.57), and the longest leaf length (11.97 cm) were found with the priming of MoP, NaCl, and ZnSO4, respectively. However, the lowest seedling growth parameters were observed in the control priming. The overall results revealed that seed priming with MoP is an effective tool to enhance the germination percentage and seedling establishment of rice. SAARC J. Agric., 21(2): 81-93 (2023)

Effect of Ligand Binding on Polymer Diffusiophoresis

Diffusiophoresis is the migration of a macromolecule in response to a concentration gradient of a cosolute in liquids. Diffusiophoresis of polyethylene glycol (PEG) in water occurs from high to low concentration of trimethylamine-N-oxide (TMAO). This is consistent with the preferential hydration of PEG observed in the presence of TMAO. In other words, PEG migrates in the direction in which it lowers its chemical potential. On the other hand, although PEG is found to preferentially bind urea in water, PEG diffusiophoresis still occurs from high to low urea concentration. Thus, PEG migrates in the direction that increases its chemical potential in the urea case. Here, a ligand-binding model for polymer diffusiophoresis in the presence of a cosolute that preferentially binds to polymer is developed. It includes both actual polymer–ligand binding and the effect of the polymer on cosolute thermodynamic activity. This model shows that polymer–cosolute binding has a marginal effect on polymer diffusiophoresis and indicates that weak repulsive interactions, such as hard-core exclusion forces, are the main factor responsible for the observed PEG diffusiophoresis from high to low urea concentration. This work contributes to a better understanding of diffusiophoresis of macromolecules in response to gradients of nonelectrolytes.

Stabilizing α-Helicity of a Polypeptide in Aqueous Urea: Dipole Orientation or Hydrogen Bonding?

We propose a mechanism for α-helix folding of polyalanine in aqueous urea that reconciles experimental and simulation studies. Over 15 μs long, all-atom simulations reveal that, upon dehydrating the protein's first solvation shell, a delicate balance between localized urea-residue dipole interactions and hydrogen bonds dictates polypeptide solvation properties and structure. Our work clarifies the experimentally observed tendency of these alanine-rich systems to form secondary structures at low and intermediate urea concentrations. Moreover, it is consistent with the commonly accepted hydrogen-bond-induced helix unfolding, dominant at high urea concentrations. These results establish a structure-property relationship highlighting the importance of microscopic dipole-dipole orientations/interactions for the operational understanding of macroscopic protein solvation.

Towards the energy landscape of adenylate kinase in crowded milieu: Activity, conformation, structure and dynamics in sequence

Enzyme function is governed by a complex network of conformational changes and internal dynamics, with the same getting more convoluted in the crowded cellular environment. Here, we have explored an intricate interplay amongst activity, structure, conformation, and dynamics of a multidomain enzyme, AK3L1 (UniProtKB: Q9UIJ7) in the crowded milieu. We have monitored changes in the enzyme landscape in response to the chemical denaturant, urea, under the influence of different concentrations of macromolecular crowders. Extensive experimental analyses using FRET-based domain displacement measurements, sub-nanosecond time scale local dynamics, and global structural changes, along with enzymatic activity studies, have been carried out to get deeper insights into the factors that may modulate the functional landscape of adenylate kinase (AK3L1). It was observed that AK3L1 gets activated at low urea concentrations, whereas higher urea concentrations unfold and thereby deactivate the enzyme. A sequential response of AK3L1 is observed towards external perturbation (urea) occurring through a series of well-defined steps. Incorporation of crowders not only shift the maximum activity of enzyme to a higher urea concentration, but also enhance domain compaction, as revealed by FRET studies. The modulation in enzyme activity and solvation dynamics acting as local response, precede global unfolding of the enzyme, indicating that the structural alterations around the active site are quite decoupled from the large amplitude global transitions.

Nitrogen forms and concentration influence the impact of titanium dioxide nanoparticles on the biomass and antioxidant enzyme activities of Microcystis aeruginosa

Nanoparticles (NPs) are becoming more widely produced, used, and released into the aquatic environment. In aquatic ecosystems, these NPs affect different populations of photosynthesizing organisms, such as cyanobacteria. This study aimed to evaluate the effects of titanium dioxide (TiO2) NPs (48mgl-1) combined with low (0.04mM) and high (9mM) concentrations of urea and nitrate on Microcystis aeruginosa. Microcystins (MCs) production and release were monitored in the cyanobacterium. The results showed that high urea concentration (9mM) combined with TiO2 NPs inhibited growth, pigment, and malondialdehyde (MDA) content by 82%, 63%, and 47%, respectively. The treatment also increased the reactive oxygen species (ROS) and glutathione S-transferase (GST) activity by 40.7% and 67.7%, respectively. Similarly, low nitrate (0.04mM) combined with TiO2 NPs inhibited growth by 40.3% and GST activity by 36.3% but stimulated pigment production and ROS concentration in M. aeruginosa. These responses suggest that high urea combined with TiO2.NPs and high nitrate combined with TiO2 NPs induced oxidative stress in cyanobacteria. The peroxidase (POD) activity of M. aeruginosa decreased by 17.7% with increasing urea concentrations. Our findings suggest that TiO2 NPs combined with changing nutrient (urea and nitrate) concentrations may adversely affect cyanobacterial development and antioxidant defense enzymes.

Visualization of Fibrillated Cellulose in Polymer Composites Using a Fluorescent-Labeled Polymer Dispersant

The fibrillated cellulose embedded in the polymer matrix was visualized using confocal laser scanning microscopy (CLSM). A rhodamine-appended diblock copolymer (RhBCP) was used as a novel polymer dispersant to adsorb fibrillated celluloses and achieve fluorescent labeling and good dispersion in high-density polyethylene. The composite was produced through in situ fibrillation of wood pulp fibers during the process of melt compounding using urea as the fibrillation-accelerating agent. The length and width of the fiber, aspect ratio, and polydispersity values were determined using RhBCP and CLSM. The optimal RhBCP content to achieve good CLSM images and a high Young’s modulus was 2 wt %. The effects of urea concentration and kneading time on the fibrillation were investigated, indicating that the fiber length and aspect ratio were approximately 40 μm and 40, respectively, under optimal conditions. The maximum Young’s modulus was recorded under these conditions, and the recorded value agreed well with the value predicted by the Halpin–Tsai equation. Cellulose fibers fragmented under conditions of low urea concentration and prolonged kneading times. The method developed has the potential to analyze various cellulosic composite systems and improve their application prospects.

Evaluation of foliar applications of urea at three concentrations on grape amino acids composition.

Grape nitrogen composition directly affects the development of alcoholic fermentation and also influences the final wine aromatic composition. Moreover, different factors influence grape amino acids composition, such as rate and timing of nitrogen application. The aim of this study was to determine the influence of three doses of urea, applied at two different phenological stages (pre-veraison and veraison), on the nitrogen composition of Tempranillo grapes during two consecutive seasons. Urea treatments did not affect vineyard yield, oenological parameters of the grapes and yeast assimilable nitrogen. However, amino acids concentration in the musts increased at both moments of urea application (pre-veraison and veraison), but the lower urea concentrations and sprayed at pre-veraison improved most of the amino acids in the musts, during two vintages. Moreover, when the year was rainy, the higher dose treatment (9 kg N ha-1 ) applied at pre-veraison and veraison improved the amino acid concentration in the must. Foliar applications of urea could be an interesting viticulture practice in order to increase the amino acids concentration in Tempranillo musts. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

An efficient microbial sealing of rock weathering cracks using bio-carbonation of reactive magnesia cement

Bio-carbonation of reactive magnesia cement (RMC) was proposed as a promising strategy to stabilize the weathered stone grains for the efficient sealing of rock weathering cracks near surface. The physical and mechanical properties of the sandstone grains stabilized by bio-carbonation of RMC was first investigated to verify the feasibility of applying the method to the rock weathering cracks when subjected to the condition of compression failure. Except for initial water content, RMC content and urea concentration, two new effects including bacteria concentration and bacteria solution composition on the underlying stabilization mechanism were systematically studied. The experimental results showed that bio-carbonation of RMC can effectively stabilize the sandstone grains. The highest unconfined compressive strength (UCS) of bio-carbonated sample was up to 5.5 MPa, which was 7.8 times higher than that of the sample stabilized by RMC hydration only. UCS increased as the RMC content and bacteria concentration increase, while the effects of initial water content and urea concentration were opposite. The dry density, resistance of water absorption, electrical resistivity and P-wave velocity were in proportion to the UCS. The effect of bacteria solution composition indicated that the well stabilization performance can be attributed to the coupling effect of the biomolecules and bacteria. Biomolecules-induced amorphous brucite can form a dense structure to fill the pore spaces. Bacteria-induced hydrated magnesium carbonates (HMCs) can form a stable spatial network structure with high cementation strength. The bacteria and biomolecules inhibited the air-based carbonation but facilitated the bacteria-based bio-carbonation and made the microstructure denser. A better bio-carbonation effect and stabilization performance can be obtained by increasing bacteria activity, such as increasing bacteria concentration or using low concentration of urea.

Experimental study on the calcium carbonate production rates and crystal size of EICP under multi-factor coupling

The production and microstructure of calcium carbonate are the fundamental indicators to evaluate the effectiveness of Enzyme-induced Carbonate Precipitation (EICP). Soybean urease is extracted, and the urease activity is controlled by the soybean powder concentration in this study. The urease reacts with the cementation solution with different concentrations of urea and calcium ions at different temperatures to determine the calcium carbonate production rates (RCC). The crystal sizes of calcium carbonate (SCC) are investigated by scanning electron microscopy (SEM) and image processing method. The RCC increase and subsequently decrease with increasing calcium ion concentration and peak at 0.75 M. A lower urea concentration is more favourable to the formation of CaCO3. Increased urease activity and temperature will lead to an increased RCC and SCC. Some crystals appear as capsules when the temperature goes up. The SCC decreases slightly with increasing calcium ion concentration under low urease activity and increases under high urease activity. The SCC increases first and subsequently decreases with increasing urea concentration under high urease activity, while the effect of urea concentration under low urease activity is not significant. XRD test results show that the calcium carbonate produced in this study is dominated by calcite crystals. The study provides additional data, a useful base to move forward toward a better understanding of the method of stabilization and its applications, for example, the treatment of different soils.

Snapshots of urea-induced early structural changes and unfolding of an ankyrin repeat protein at atomic resolution.

Protein folding and unfolding is a complex process, underscored by the many proteotoxic diseases associated with misfolded proteins. Mapping pathways from a native structure to an unfolded protein or vice versa, identifying the intermediates, and defining the role of sequence and structure en route remain outstanding problems in the field. It is even more challenging to capture the events at atomistic resolution. X-ray diffraction has so far been used to understand how urea interacts with and unfolds two stable globular proteins. Here, we present the case study on PSMD10Gankyrin , a prototype for a moderately stable, non-globular repeat protein, long and rigid, with its termini located at either end. We define structural changes in the time dimension using low urea concentrations to arrive at the following conclusions. (a) Unfolding is rapidly initiated at the C-terminus, slowly at the N-terminus, and proceeds inwards from both ends. (b) C-terminus undergoes an α to 310 helix transition, representing the structure of a potential early unfolding intermediate before disorder sets in. (c) Distinct and progressive changes in the electrostatic landscape of PSMD10Gankyrin were observed, indicative of conformational changes in the seemingly inflexible motif involved in protein-protein interaction. We believe this unique study will open up the field for better and bolder queries and increase the choice of model proteins for a better understanding of the challenging problems of protein folding, protein interactions, protein degradation, and diseases associated with misfolding.

Hepatic urea, creatinine and uric acid metabolism in dairy cows with divergent milk urea concentrations

Milk urea concentration is an indicator for dietary nitrogen (N)-supply and urinary N-excretion. Dairy cows with high (HMU) compared to low milk urea (LMU) concentration have greater plasma urea, creatinine and uric acid concentrations, but if the liver metabolism accounts for these differences is unknown. Eighteen HMU and 18 LMU cows were fed a diet with a low (LP) or normal (NP) crude protein concentration. A N balance study was performed and a 13C-urea bolus was administered to measure urea pool size. Liver samples were analyzed by 2D-gel-based proteomics and RT-qPCR. Although HMU cows had a greater urea pool, plasma urea, uric acid, and hippuric acid concentrations, these differences were not associated with altered expressions of genes related to urea cycling or N-metabolism. Instead, HMU cows had higher oxidative stress levels. Conclusively, other factors than hepatic urea metabolism account for milk urea concentrations. Despite higher plasma urea concentrations and argininosuccinate synthase 1 protein expression on the LP diet, urea cycle mRNA expressions were not affected, indicating that its activity is not controlled at transcriptional level. Feeding the LP diet resulted in increased expressions of enzymes catabolizing fatty acids, but the reason remains to be investigated in future studies.

Unveiling the quantification minefield in electrocatalytic urea synthesis

Electrochemical synthesis of urea from carbon dioxide and nitrogenous species is a promising sustainable strategy, which can be easily incorporated into distributed renewable energy systems. However, a low concentration of urea produced in a complex solution environment brings challenges to its accurate quantification. Here an overall comparison (e.g., accuracy, reliability, anti-interference ability) of the frequently-used determination methods is provided after considering the potential interference factors. Besides, a rigorous urea detection flowchart and a recommended standard are established to achieve a more accurate and responsible performance evaluation in electrocatalytic urea production. This work guides the reliable quantification in urea synthesis, especially at a low concentration within a complicated electrocatalytic system.

Opioid-induced respiratory depression and risk factors in a tertiary hospital: A retrospective study

BackgroundOpioids are potent analgesics used for the treatment of moderate to severe acute and chronic cancer and non-cancer pain. However, opioid usage may be limited by negative side effects, such as potentially life-threatening respiratory depression. ObjectivesThe aim of our study is to investigate the prevalence of opioid-induced respiratory depression (OIRD) and its predictors at King Abdulaziz Medical City in Jeddah (KAMC-JD). MethodThis is a retrospective cross-sectional (chart review) study conducted from January 1, 2016, to December 31, 2020. ResultsA total of 15,753 patients received opioids during admission to KAMC-JD, and only 144 (0.915%) of them received naloxone from January 1, 2016 to December 31, 2020. Only 91 patients (0.57%) developed opioid-induced respiratory depression (OIRD), which was more frequently reported among young and middle-aged adults. OIRD was significantly associated with receiving a daily morphine milligram equivalent (MME) dose of ≥150 MME and with having a low urea concentration at the baseline and at admission under surgery. Also, fentanyl use remained a significant risk factor for OIRD. ConclusionIn conclusion, monitoring patient receiving opioids with a daily MME dose of ≥150 MME, prescribed Fentanyl, low urea concentration at the baseline, and patients’ admissions to the surgery department may mitigate the risk of developing OIRD.

The effect of spin exchange interaction on protein structural stability.

Partially charged chiral molecules act as spin filters, with preference for electron transport toward one type of spin ("up" or "down"), depending on their handedness. This effect is named the chiral induced spin selectivity (CISS) effect. A consequence of this phenomenon is spin polarization concomitant with electric polarization in chiral molecules. These findings were shown by adsorbing chiral molecules on magnetic surfaces and investigating the spin-exchange interaction between the surface and the chiral molecule. This field of study was developed using artificial chiral molecules. Here we used such magnetic surfaces to explore the importance of the intrinsic chiral properties of proteins in determining their stability. First, proteins were adsorbed on paramagnetic and ferromagnetic nanoparticles in a solution, and subsequently urea was gradually added to induce unfolding. The structural stability of proteins was assessed using two methods: bioluminescence measurements used to monitor the activity of the Luciferase enzyme, and fast spectroscopy detecting the distance between two chromophores implanted at the termini of a Barnase core. We found that interactions with magnetic materials altered the structural and functional resilience of the natively folded proteins, affecting their behavior under varying mild denaturing conditions. Minor structural disturbances at low urea concentrations were impeded in association with paramagnetic nanoparticles, whereas at higher urea concentrations, major structural deformation was hindered in association with ferromagnetic nanoparticles. These effects were attributed to spin exchange interactions due to differences in the magnetic imprinting properties of each type of nanoparticle. Additional measurements of proteins on macroscopic magnetic surfaces support this conclusion. The results imply a link between internal spin exchange interactions in a folded protein and its structural and functional integrity on magnetic surfaces. Together with the accumulating knowledge on CISS, our findings suggest that chirality and spin exchange interactions should be considered as additional factors governing protein structures.

Unraveling the structural basis of urea-induced unfolding of Fasciola gigantica cytosolic malate dehydrogenase

Malate dehydrogenase enzyme plays an essential role in energy metabolism in all eukaryotes. It catalyzes the interconversion of malate to oxaloacetate, producing NAD+/NADH. In the current study, we monitored the urea-induced conformational changes in Fasciola gigantica malate dehydrogenase (FgMDH) structure using multiple spectroscopic techniques combined with all-atom molecular dynamics (MD) simulations. FgMDH showed a two-state cooperative unfolding revealed by intrinsic tryptophan (Trp) fluorescence and CD spectroscopy; however, their non-superimposable curves indicate a partially folded intermediate state formation. The study showed that the unfolding of tertiary structures preceded the secondary structure unfolding. The binding of the fluorescence probe 1-anilino-8-naphthalene sulfonate (ANS)at 1.5 M urea confirmed stabilization of the intermediate state. The free energy of stabilization determined from Trp fluorescence and CD spectroscopy were 11.4 and 13.2 kcal.mol−1, respectively. The loss of enzymatic activity was observed before any significant loss in structural components. This suggested that low urea concentrations induce minor structural changes in the substrate or cofactor binding site leading to activity loss. Quenching of fluorescence intensity also provides information on unfolding and activity loss. MD simulations confirmed that FgMDH formed an intermediate state at 1.5 M urea at 300 K, which destabilized at higher urea concentration and temperature due to disrupted hydrogen-bond networks and hydrophobic interactions. We conclude that a partially folded metastable state is stabilized during the unfolding of cytosolic FgMDH. A strong correlation was observed between the data obtained from in-vitro and in-silico approaches.

Assessment of the Effects of a High Amikacin Dose on Plasma Peak Concentration in Critically Ill Children.

This study aimed to assess the incidence of amikacin plasma peak concentration (Cmax) below 60 mg·L-1 in critically ill children receiving an amikacin dosing regimen of 30 mgkg-1·day-1. Secondary objectives were to identify factors associated with low Cmax and to assess the incidence of acute kidney injury (AKI). A retrospective observational study was performed in two French pediatric intensive care units. All admitted children who received 30 mg·kg-1 amikacin and had a Cmax measurement were eligible. Clinical and biological data, amikacin dose, and concentrations were collected. In total, 30 patients were included, aged from 3 weeks to 7 years. They received a median amikacin dosage of 30 mgkg-1·day-1 (range 29-33) based on admission body weight (BW), corresponding to 27 mgkg-1·day-1 (range 24-30) based on actual BW. Cmax was < 60 mg·L-1 in 21 (70%) children and none had a Cmax ≥ 80 mg·L-1. Among the 15 patients with a measured minimum inhibitory concentration (MIC), 13 (87%) had a Cmax/MIC ratio > 8. Univariate analysis showed that factors associated with Cmax < 60 mg·L-1 were high estimated glomerular filtration rate (p = 0.015) and low blood urea concentration (p = 0.001). AKI progression or occurrence was observed after amikacin administration in two (7%) and six (21%) patients, respectively. Despite the administration of the maximal recommended amikacin dose, Cmax was below the pharmacokinetic target in 70% of our pediatric population. Further studies are needed to develop a pharmacokinetic model in a population of critically ill children to optimize target attainment.

Performance and serum parameters of calves (Bos taurus) subject to milk restriction associated with supplementation with 2-hydroxy-4-(methylthio)butanoic acid.

Our aim with this study was to evaluate the consumption, performance, quantitative characteristics of carcasses, biochemical profile, plasma levels of ghrelin and leptin, expression of the receptor for ghrelin (GHS-R1a) in the hypothalamus and duodenum, and the number of goblet cells in the duodenum of calves subjected to milk volume restriction and supplemented with 2-hydroxy-4-(methylthio)butanoic acid (HMTBa). We used 21 Holstein mixed-breed calves, aged between 3 and 15 d with an average weight of 36.8 kg, and housed in pens with troughs for hay, concentrate, and water. The study included two consecutive experimental periods (first period [P1] and second period [P2]) of 21 d each, with 7 d of adaptation to the diet and facilities. The calves were distributed in a completely randomized design in three treatments with seven repetitions. 1) Control: 6 liters of milk/d during P1 and 6 liters of milk/day during P2; 2) RES (milk restriction): 3 liters of milk/day during P1 and 6 liters of milk/day during P2; and 3) RES + HMTBa: 3 liters of milk/day during P1 and 6 liters of milk/day during P2 + 3.3 g of HMTBa/day in both periods. HMTBa was supplied in milk, and the amount of concentrated ration and hay provided and leftovers were recorded daily to estimate dry matter (DM) and crude protein consumption. Mean daily weight gain (DWG), final weight (FW), and feed conversion (FC) were obtained at the beginning and at the end of each 21-d period. Plasma concentrations of ghrelin and leptin, triglycerides, total protein, urea, lactate, creatinine, alkaline phosphatase, and cholesterol were measured for P1 and P2 at the end of each 21-d period. At the end of P2, animals were slaughtered; sections of the duodenum were collected to evaluate the expression of GHS-R1a and quantity of goblet cells; hypothalamus was used to evaluate the expression of GHS-R1a; rumen was used to evaluate the thickness of epithelium and keratin and the density, height, and width of ruminal papillae. In P1, total DM consumption, FW, DWG, glucose, and triglycerides were lower in the RES and RES + HMTBa groups (P < 0.001). In P2, there was an improvement in the FC of the RES + HMTBa group (compared with Control and RES groups) and a lower urea concentration in the RES group (compared with Control and RES + HMTBa groups) (P < 0.001). No differences were observed among groups regarding hormonal concentrations, histological parameters, and GHS-R1a expression in the duodenum and hypothalamus. Therefore, milk restriction combined with HMTBa supplementation promoted greater compensatory gain by a mechanism independent of changes in GHS-R1a expression and hormone levels of ghrelin and leptin.

The Role of Endothelins, IL-18, and NGAL in Kidney Hypothermic Machine Perfusion.

Ischemia-reperfusion injury (IRI) occurring after renal transplantation is a complex biochemical process that can be monitored by specific biomarkers. The roles of those are not yet fully elucidated. The aim of this study was to analyze the concentrations of endothelins (ET-1, ET-2, and ET-3), interleukin-18 (IL-18), and neutrophil gelatinase-associated lipocalin (NGAL) during the reperfusion of human kidneys grafted from brain dead donors and later transplanted. The study group (n = 44) was analyzed according to the method of kidney storage: Group 1 underwent hypothermic machine perfusion (HMP) in the LifePort perfusion pump (n = 22), and Group 2 underwent static cold storage (SCS) (n = 22). The analysis of kidney function was performed daily during the first seven days after transplantation. The kidneys in Group 1 were characterized by higher absolute concentrations of ET-1, IL-18, and NGAL, as well as a lower concentration of ET-2 (p = 0.017) and ET-3. The relative increase of ET-1 (p = 0.033), ET-2, and ET-3 during reperfusion was lower in this group, while the relative decrease of NGAL was higher. Group 1 was also characterized by significant decrease of IL-18 (p = 0.026) and a tendency for better kidney function based on the higher total diuresis, higher glomerular filtration rate (GFR), higher potassium level, lower serum creatinine, and lower urea concentration during the seven-day postoperative observation period. The long-term beneficial impact of hypothermic machine perfusion on the outcome of transplanted kidneys may rely on the early modified proceedings and intensity of ischemia-reperfusion injury reflected by the dynamics of the concentrations of examined biomarkers.

The In vivo Trend Analysis of Kidney Function Indices and Lipid Profile of Albino Rats Administered Palm-Wine

The present study evaluated the dynamics of kidney function indices and lipid profile of albino rats after administration of palm-wine to them. The fresh palm-wine was collected from a local palm-wine tapper on daily basis and divided in to two portions. The first portion was labelled “Fresh palm-wine” and administered (15 ml/kg) to group 2 and (30 ml/kg) to group 4, the second portion was allowed to ferment for additional ten hours and labelled “prolonged-fermented palm-wine” and administered (15 ml/kg) to group 3 and (30 ml/kg) to group 5. Group one served as the control and received distilled water, all for 28 days. Each group was randomly allocated four rats. Results (mmol/ml) revealed a significantly(p&lt;0.05) lower concentration of urea (10.21±0.40), higher creatinine (0.37±0.17), K+ (4.06±0.06) and Cl- (86.12±4.61) in group 2 when compared to the control; 11.035±.110, 0.395±0.06, 3.945±.064, 80.090±0.25 respectively. In group 3, the concentrations of urea (11.70±0.35), creatinine (0.42±0.12) and Cl- (88.57±0.50) were significantly (p&lt;0.05) higher when compared to the control. Na+ (120.09±10.40) was significantly (p&lt;0.05) higher in group 4 when compared to the control (100.065±0.75). TAG (in mg/dL) (2.18±0.10) was significantly(p&lt;0.05) higher in group 2 compared to control (1.96±0.023). T. cholesterol (3.125±0.27) and LDL-C (1.64±0.47) were significantly (p&lt;0.05) lower in group 3 compared to the control; 1.99±0.052, respectively with significantly(p&lt;0.05) elevated HDL (1.11±0.22) compared to control (0.840±0.092). TAG (2.190±0.25) and HDL-C (1.15±0.23) increased significantly(p&lt;0.05) while LDL-C (1.58±0.14) decreased significantly (p&lt;0.05) in group 4 compared to control; 1.960±0.023, 0.840±0.092, 1.985±0.052 respectively. T. cholesterol (2.93±0.08) and LDL-C (1.56±0.03) decreased significantly(p&lt;0.05) with significant(p&lt;0.05) increase in HDL-C (0.99±0.10) in group 5 compared to the control. Fresh and prolonged-fermented palm-wine may adversely affect kidney function indices and lipid profile.