Low Molecular Weight Substances Research Articles

Survey on Adsorption of Low Molecular Weight Compounds in Cu-BTC Metal-Organic Framework: Experimental Results and Thermodynamic Modeling.

This contribution aims at providing a critical overview of experimental results for the sorption of low molecular weight compounds in the Cu-BTC Metal–Organic Framework (MOF) and of their interpretation using available and new, specifically developed, theoretical approaches. First, a literature review of experimental results for the sorption of gases and vapors is presented, with particular focus on the results obtained from vibrational spectroscopy techniques. Then, an overview of theoretical models available in the literature is presented starting from semiempirical theoretical approaches suitable to interpret the adsorption thermodynamics of gases and vapors in Cu-BTC. A more detailed description is provided of a recently proposed Lattice Fluid approach, the Rigid Adsorbent Lattice Fluid (RALF) model. In addition, to deal with the cases where specific self- and cross-interactions (e.g., H-bonding, Lewis acid/Lewis base interactions) play a role, a modification of the RALF model, i.e., the RALFHB model, is introduced here for the first time. An extension of both RALF and RALFHB is also presented to cope with the cases in which the heterogeneity of the rigid adsorbent displaying a different kind of adsorbent cages is of relevance, as it occurs for the adsorption of some low molecular weight substances in Cu-BTC MOF.

Characterization of DOM Released from Bacteria in Response to Chlorine in Water Based on Indicator Bacteria E. coli

In this study, Escherichia coli (E. coli) was used as an indicator bacterium treated with five different concentrations of chlorine (0.1; 0.5; 1.0; 2.0, and 5.0 mg/L) and without chlorine (0.0 mg/L) to evaluate the changes in the DOM characteristics. The dissolved organic carbon (DOC) concentration initially increased along with the chlorine concentrations and decreased after 24 hours (0.0 and 0.1 mg/L) and 168 hours (0.5; 1.0; 2.0 and 5.0 mg/L). Ultra-violet absorbance at 260 nm (UV260) showed that the absorbance decreased for control without chlorine (0.0 mg/L) and 0.1 mg/L chlorine, while increased for other concentrations of chlorine within 120 hours. The DOC and UV260 results indicated that the high concentrations of chlorine initiated high contents of DOM which contained more humic-like molecules than the DOM released from E. coli without chlorine. Fluorescence excitation-emission matrix (EEM) analysis suggested that the DOM released from E. coli without chlorine enriched with protein-like substances, whereas the fulvic-like and humic-like substances more intensified in the DOM for the high concentrations of chlorine (>1.0 mg/L). The molecular weight distribution of DOM showed that the intensity of high molecular weight substances and polydispersity increased along with chlorine concentration and contact time, whereas the low molecular weight substances were relatively higher in the DOM for control without chlorine. The obtained results of this study would be useful for a better understanding of the variation of DOM during treatment and could be used as an important reference for optimizing the operation condition of the water treatment plants.

Biochemical disorders in the thyroid gland in rats with hyperhomocysteinemia

Background: In recent years, significant progress has been made in elucidating the mechanisms of development of complications associated with hyperhomocysteinemia (HC), but little is known about the disorders in the thyroid gland. This study aimed to determine the levels of low-molecularweight degradation products and peptides in the thyroid gland of rats with HC. In addition, markers of inflammation and the proteolytic state were also assessed. Methods: HC was induced by intragastric administration of DL-homocysteine thiolactone (100 mg.kg-1 of body weight) to albino non-linear male rats. The levels of low-molecular-weight substances (LMWS) of various nature were detected at wavelengths of 254 and 280 nm. The levels of MMP-2 and cytokine profiles were detected by enzyme-linked immunosorbent assay. The protein composition and the presence of active enzymes were assessed by SDS-polyacrylamide gel electrophoresis and zymography, respectively. Results: Obtained results can indicate the enhancement of catabolic reactions, confirmed by the accumulation of LMWS in the blood and thyroid gland of the rats with HC. The state of inflammation, evidenced by the significantly increased pro-inflammatory cytokines, was also revealed. HC was accompanied by the activation of proteolysis, expressed by an increase in overall proteolytic activity, the level of MMP-2, and changes in protein profile. Proteins accumulated with a molecular weight of less than 30 kDa simultaneously with the decrease in the level of high-molecular-weight proteins.

The desorption mechanism of dissolved organic matter on pollutants and the change of biodiversity during sediment dredging

Sediment dredging is an effective means to control the endogenous pollution of lakes, which could significantly change the concentration and composition of organic matter, especially dissolved organic matter (DOM) in the lake. DOM is particularly important for the release of endogenous pollutants, which will inevitably bring an impact on aquatic biodiversity. Nevertheless, in recent research little attention has been paid to the desorption mechanism of DOM on pollutants and the change of biodiversity during dredging. This study investigated the physicochemical properties of DOM in the sediment by taking a sediment dredging project in Dianchi Lake in China for example. The correlations of DOM properties with the desorption behavior of nitrogen (N), phosphorus (P), cadmium (Cd), lead (Pb) and the biodiversity of aquatic organisms were analyzed. The results show that the aromaticity and humification of DOM were improved after dredging, and the high molecular weight DOM was degraded into low molecular weight substance. The desorption amount of N, P and heavy metals (Cd, Pb) were decreased as the pH values increased. Moreover, NH4+-N promoted the release of Pb2+ from DOM, while the release of PO43--P was inhibited. Correlation analysis shows that the physicochemical properties of DOM exactly affected the release of N, P, Cd and Pb. It was easier to desorb pollutants with low aromaticity and humification of DOM, leading to a decrease in the diversity of aquatic organisms. This study identified the desorption mechanism of endogenous pollutants in DOM and the ecological risk to aquatic organisms, providing a theoretical basis for the prevention and control of water pollution.

Evaluation of intraperitoneal administration of glucose solution using in the treatment of ketosis in dairy cows

Ketosis in high‐yielding dairy cows is the most common metabolic pathology during late dryness and early lactation. This work aims to establish the possibility and effectiveness of therapy for ketosis in dairy cows through the intraperitoneal injection of a 20% glucose solution. For the experiment, on days 21‐30 of lactation, two groups of black‐and‐white cows with a β‐hydroxybutyrate level above 1.0 mmol / l were formed. Animals of the first group (n = 10) were injected four times with an interval of 24 hours intraperitoneally with 1000 ml of 20% dextrose solution. Cows of the second group (n = 10) in a similar regimen were injected dextrose intravenously. Blood for research was obtained before the start of injections, after 5, 30 minutes, 1, 2, 3 hours after the first injection of the solution, and one day and seven days after the end of therapy. It was found that a single intravenous injection of dextrose during the first 5 minutes is accompanied by an increase in the concentration of the monosaccharide in the blood by 2.2 times (from 5.1 to 11.4 mmol / L; P <0.001). The level decreases to the initial values within 1 hour, and intraperitoneal infusion does not cause hyperglycemia. A redistribution of protein fractions accompanies therapy of cows with ketosis: a decrease in the albumin‐globulin coefficient by 16.8% (P <0.05) with intraperitoneal administration and by 26.9% (P <0.01) with intravenous administration. The activity of AST after intracavitary injections of dextrose decreased by 36.5% (P <0.05). The loading of erythrocytes with substances of low and medium molecular weight was 19.4% (P <0.05) with the intraperitoneal injection. It was not observed with the intravascular route of administration. The morphological composition of blood after intravenous administration of dextrose was characterized by an increase in the level of leukocytes by 34.8% (P <0.05), a decrease in erythrocytes by 11.9% (P <0.05), hemoglobin by 11.6% (P <0, 05), hematocrit by 12.3% (P <0.05). Therapy via intraperitoneal injection did not cause pronounced changes in these parameters. The intravenous administration of glucose promoted a more rapid elimination of ketone bodies, which decreased by 2 times one day after the end of therapy (P <0.05), but after 7 days, their level began to increase again (by 21.1%). It did not have significant differences with indicators at the time of diagnosis. Intraperitoneal infusions were accompanied by a slight decrease (by 16.3%) in the level of β‐hydroxybutyrate one day after the end of therapy, followed by a pronounced decrease in the concentration of ketones by day 7 (2.3 times; P <0.01). The dynamics of fructosamine indicate that intracavitary injections do not cause glycosylation of plasma proteins, while intravenous infusions increase the values by 37.0 ‐ 39.4% (P <0.001). Thus, intraperitoneal administration of glucose during ketosis in dairy cows has a more favorable effect on the morphobiochemical composition of the blood and provides a more prolonged therapeutic effect.

УРОВЕНЬ ВЕЩЕСТВ СРЕДНЕЙ И НИЗКОЙ МОЛЕКУЛЯРНОЙ МАССЫ И ОЛИГОПЕПТИДОВ У БОЛЬНЫХ ИНФАРКТОМ МИОКАРДА НА ФОНЕ ХРОНИЧЕСКОЙ ОБСТРУКТИВНОЙ БОЛЕЗНИ ЛЁГКИХ С ОДНО- И МНОГОСОСУДИСТЫМ ПОРАЖЕНИЕМ КОРОНАРНЫХ АРТЕРИЙ

Introduction. The presence of endogenous intoxication syndrome in somatic pathology worsens the course and prognosis of diseases. It is especially urgent to study this syndrome in comorbid pathology, in particular, in myocardial infarction development in patients with chronic obstructive pulmonary disease. The objective markers of endogenous intoxication are medium and low molecular weight substances and oligopeptides. Aim. The aim is to estimate the severity of endogenous intoxication syndrome by studying the levels of medium and low molecular weight substances and oligopeptides in patients with myocardial infarction developed against the background of chronic obstructive pulmonary disease depending on the number of coronary arteries affected. Material and meth- ods. 225 patients with myocardial infarction were examined. In 130 of them the infarction developed as monosomal disease, and in 195 - against the background of previously documented chronic obstructive pulmonary disease. Among patients with myocardial infarction as monoinflammation, 71 (64.5%) had a single-vessel lesion and 59 (35.5%) had a multivessel lesion. Among patients with myocardial infarction against chronic obstructive pulmonary disease, lesion of the 1st coronary artery was found in 50 patients (25.6%), and multivessel lesion was found in 145 (74.4%). The comparison group included 110 somatically healthy subjects. We used direct spectrometry (according to M.Y. Malakhova, 1995) to determine the levels of medium and low molecular weight substances and oligopep- tides. Statistical data processing was carried out using software package SPSS 26.0. Results and discussion. In the group of patients with myocardial infarction the levels of medium and low molecular weight substances and oligopeptides and calculated indices showed significant differences in single- and multivessel lesions. In the 1st coronary artery lesion, the indices in most cases were comparable with the values in the control group. In the group of myocardial infarction patients with multivessel lesions, the values of medium and low molecular weight substances and oligopeptides increased significantly. In patients with myocardial infarction against the background of chronic obstructive pulmonary disease, all intoxication parameters were significantly higher compared not only with the control, but also with patients with myocardial infarction as monoinflammation. However, the values in the subgroups with single and multivessel lesions did not demonstrate statistical reliability. Conclusion. The number of affected vessels, and hence the volume of ischemic myocardium, affects the severity of endogenous intoxication in patients with myocardial infarction as mononasal. In this case, the elimination function of the excretory organs is not impaired, which means that the level of intoxication is due to the production of toxins in conditions of ischemia and myocardial necrosis. In conditions of cardiorespiratory comorbidity chronic obstructive pulmonary disease con- tributes significantly to the development of endogenous intoxication, aggravating it and levelling the differences occurring in monosensing.

Экскреция триптофана, лизина, триметиллизина, саркозина, холина и 4-пиридоксиновой кислоты с мочой при мочекаменной болезни

Introduction. The role of the organic matrix in urinary stones genesis in urolithiasis patients is still unclear. The presence of a large amount of protein in the urinary stones matrix suggests the participation of the protein matrix in lithogenesis. Research of the amino acids spectrum in urine is of great interest so far as amino acids are the part of the matrix proteins of the urinary stone. Material and methods. We analyzed urinary excretion of the following amino acids and low molecular weight compounds: tryptophan, lysine, trimethyllysine, sarcosine, choline and 4-pyridoxine acid. We used ultra-performance liquid chromatography in combination with a TQD mass spectrometer. Results. A higher level of excretion of choline and sarcosine is typical for patients with oxalate stones, compared with healthy people. Uric acid stone patients have high concentration of choline and extremely increased concentration of trimethyllysine in the urine unlike healthy individuals. Very low concentration of trimethyllysine, choline, sarcosine and higher excretion of tryptophan are specific for oxalate urolithiasis, in contrast to urate stone patients. Conclusion. The intensity of amino acids and low molecular weight compounds urinary excretion has characteristic features in patients with various types of urolithiasis and healthy individuals. Indicators of excretion of these amino acids and low molecular weight substances can serve as criteria for the activity of oxalate or urate lithogenesis along with the known metabolic lithogenic factors of urine. We can use it as additional target indicators to assess the success of anti-relapse treatment.

Role of biological granular activated carbon in contaminant removal and ultrafiltration membrane performance in a full-scale system

This study evaluated a long-term impact of biological activated carbon (BAC) filter that was employed in a full-scale drinking water treatment plant to enhance the removal of contaminants by the ultrafiltration (UF) process. The results showed that BAC enhanced UF performance by increasing the flux by 18.5% and extending the filtration run by 45%. The presence of BAC improved the removal of primary contaminants, including dissolved organic carbon (4–40%), UV 254 (10–57.7%), geosmin and 2-methylisoborneol (80%). BAC was also effective in decreasing the concentration of biopolymers, humic substances, (semi-)volatile organics, chlorite and halonitromethanes, thereby lowering contaminant load on the UF unit. The changes in primary water quality parameters in the combined process showed that the humic substances in dissolved organic nitrogen, low molecular weight substances in UV 254 , and fluorescence protein-like substances could be useful indicators for DBPs as these organic fractions had strong correlation with DBPs. Obvious spatio-temporal characteristics of GAC grain and microbial communities in BAC filter were observed with operation time and filter depth. The bacterial community in BAC filter was highly diverse and was less influenced by influent quality with an increase in filter depth, while the communities in UF cake layer correlated with organic removal in the UF system. • The BAC performance in a hybrid full-scale DWTP in combination with UF was studied. • BAC could increase the UF flux by 18.5% and extend the filtration run by 45%. • BAC removed 4–40% of DOC, 10–57.7% of UV 254 and 80% of 2- MIB in sand filtrate. • BAC was more effective in controlling N-DBPFP than C-DBPFP, in particular for HNMs. • The microbial communities in BAC filter exhibited temporal and spatial variability.

About the effect of ethanol on the level of substances of low and medium molecular weight

The aim of this work is to study the effect of the concentration of ethanol in the blood on the level of low and medium molecular weight substances in the urine and blood of corpses. The content of LMMWS in the blood and urine of corpses without ethanol in the blood and its concentration of 0.5-1.5 ‰ and 2.0-5.0 ‰ was determined by the method of Malakhova modified by Kopytova at wavelengths of 238-298 nm. The dependence of the concentration of LMMWS in urine on the concentration of ethanol in the blood is shown: the decrease in the parameters of LMMWS in urine is the more pronounced, the higher the concentration of ethanol in the blood. One of the probable mechanisms of such a decrease is the neurotoxic effect of ethanol, leading to polyuria and a decrease in the concentration of various substances in the urine.Работы — изучение влияния концентрации этанола в крови на содержание веществ низкой и средней молекулярной массы (ВНСММ) в моче и крови трупов. Определяли содержание ВНСММ в крови и моче трупов без этанола в крови и при концентрации 0,5—1,5 и 2—5 ‰ по методике Малаховой в модификации Копытовой при λ=238—298 нм. Показана зависимость количества ВНСММ в моче от концентрации этанола в крови: снижение содержания ВНСММ в моче тем более выражено, чем выше концентрация этанола в крови. Один из вероятных механизмов такого снижения — нейротоксическое действие этанола, приводящее к полиурии и снижению содержания различных веществ в моче.

Cytosorb® haemoadsorption: a potential game changer for patients needing myocardial surgical revascularisation

Cytosorb, an extracorporeal blood purification system, utilises the principles of haemoadsorption to remove low molecular weight substances from the blood, including multiple cytokines such as interleukin (IL)-1b, IL-6, IL-8, and tumour necrosis factor-α, and anti-platelet drugs aiming to improve clinical outcomes. Given the prominent role of pro-inflammatory cytokines in various inflammatory states, Cytosorb has seen growing application as a therapeutic immunomodulator including surgery. This review focuses on the effects of the use of Cytosorb in patients undergoing coronary artery bypass grafting (CABG) and the indications of removal of cytokines and anti-platelet agents such as ticagrelor. The evidence supports the feasibility and safety profile of Cytosorb, with no device-related adverse events reported in all studies. Initial studies suggest significant potential for Cytosorb in urgent or emergency CABG surgery to remove anti-platelet medication with promising benefits on clinical outcomes including fewer blood product transfusions, decreased length of intensive care unit stay, and lower re-sternotomy rates. Furthermore, a cost saving analysis indicated that intraoperative removal of ticagrelor with Cytosorb would be cost effective in the setting of emergency cardiac surgery. However, the evidence remains inconclusive when Cytosorb is used in elective CABG surgery for cytokine removal. Definite high quality clinical trials for both indications for Cytosorb in CABG surgery are needed to clarify if there is a clinically significant benefit in clinical outcomes. There is substantial trial activity for the application of Cytosorb in higher risk cardiac surgery to establish the place of Cytosorb in future treatment pathways in cardiac surgery.

EFFECTS OF MOLECULAR WEIGHT ON MICROFLUIDIC SEPARATION

the molecular weight effects the diffusion of molecules in the interface of laminar flow form in a microfluidic channel. Two mixtures of PS with anisole and PEG were used to evaluate the molecular weight effect on the microfluidic separation. Also, the separation of a low molecular weight substance of anisole from the mixture with a high molecular weight substance of PS is proved experimentally. However, the separation of PEG from the mixture with PS remained difficulty. More information about diffusion in microfluidic channel and can be applied to polymer science and separation fields.

Myths and reality about the effects of glutamate. Compilation of scientific data of modern world literature

The aim of our scientific work was to study the existing experimental models of glutamate effects on the body and to understand the mechanisms of this effect and its possible consequences. To achieve this goal, we have studied different sources of scientific medical literature. Results. In a healthy body, glutamic acid is secreted by brain neurons in the required amount as a neurotransmitter and participates in the main information flows of human body. Sodium glutamate, which enters the body with food in large quantities, affects the body, causing general toxic effects and has a local effect on the stomach, intestines, salivary glands and pancreas and so on. Based on the scientific literature, experimental models that study the effects of glutamate are divided into two types: models in which glutamate enters the body orally and when glutamate is administered subcutaneously and intraperitoneally in the neonatal period of life. In the first route of administration, glutamate causes a toxic effect, which is manifested in increased catalytic activity in the blood serum of alanine aminotransferase, aspartate aminotransferase and gamma-glutamyltranspeptidase in 2.5; 1.6; and 1.5 times, respectively, while the activity of alkaline phosphatase remained at control levels, indicating a pronounced hepatotoxic effect of monosodium glutamate as a dietary supplement. It causes an increase in content of total and tyrosine-containing peptides in the blood serum, increase of substances of low and medium molecular weight, as well as an increase in the values of intoxication, which indirectly indicates a violation of the detoxification of endogenous metabolites in the liver of experimental animals. Ingestion of sodium glutamate within the recommended doses has not been shown to cause marked pathological changes in the mucous, muscular and serous membranes of the gastric wall, but there is a slight fullness of the vessels of the submucosal membrane. It has been found that in high doses, sodium glutamate has a local pathogenic effect on the tissues of the stomach, which consists in thinning all layers of its wall, desquamation of the mucous membrane and its disorganization by reducing the size of gastric glands, increasing the number of vessels and their fullness with blood. One of the mechanisms of pathogenic effect of sodium glutamate is the contact local and free radical oxidizing effect on gastric tissues. In the oral route of administration of glutamate there are no phenomena of fat growth (obesity) as epidermal, which is characteristic of the abdominal form of obesity, so and pararectal, parallelic, pararenal and retroperitoneal, which is characteristic for the visceral form of obesity. In the subcutaneous and intraperitoneal routes of administration of glutamate in the neonatal period of life in experimental animals, glutamate causes hypersecretion of hydrochloric acid, the development of lesions manifested by hemorrhage, erosions and ulcers in the gastric mucosa and obesity. Prolonged administration of monosodium glutamate significantly enhances the striking effects of stress on the gastric mucosa. Morphological studies of the submandibular salivary glands of rats on the background of glutamate-induced obesity confirm the development of pathological changes, as evidenced by the detected vacuolar dystrophy in the acinar region, perivascular and periductal edema. On the background of abdominal obesity, dystrophic processes were found in the acinuses and minor dystrophic changes in the intraparticle inserts. Conclusion. In the subcutaneous and intraperitoneal routes of administration of glutamate in the neonatal period of life in experimental animals, glutamate causes hypersecretion of hydrochloric acid, the development of lesions manifested by hemorrhage, erosions and ulcers in the gastric mucosa and obesity. Prolonged administration of monosodium glutamate significantly enhances the striking effects of stress on the gastric mucosa. Morphological studies of the submandibular salivary glands of rats on the background of glutamate-induced obesity confirm the development of pathological changes, as evidenced by the detected vacuolar dystrophy in the acinar region, perivascular and periductal edema. On the background of abdominal obesity, dystrophic processes were found in the acinuses and minor dystrophic changes in the intraparticle inserts. There is no doubt in the fact, which is based on the results of numerous experimental studies and covered in professional scientific litefrature, that the abdominal form of glutamate-induced obesity is possible only with subcutaneous and intraperitoneal routes of its administration in the neonatal period of life and while intraorall way of administration does not occur.

Effects of temperature shocks on the formation and characteristics of soluble microbial products in an aerobic activated sludge system

The present study investigated the impacts of temperature shocks on the generation of soluble microbial products (SMPs) in an aerobic activated sludge system, focusing on biopolymers and low molecular weight (LMW) substances that significantly impact the effluent quality. The results indicated that raising the temperature increased SMP production. At 25 and 35 °C, all size fractions of SMPs increased linearly with the aeration time, and biopolymers comprised a large proportion of SMPs. At 5 and 15 °C, in contrast, only biopolymers increased linearly with the aeration time, and LMW substances were the predominant fraction of SMPs. The reduced bio-utilization of SMPs with an increase in temperature was associated with the decreased relative abundance of LMW substances, which is supported by the assimilable organic carbon bioassay measurements. The mass of the biopolymers for the SMPs and extracellular polymeric substances (EPS) was balanced at all temperatures, wherein a negative correlation was observed, indicating that increased SMPs in the water phase led to a decrease in EPS. The results of the reactive oxygen species (ROS) and toxicity assays confirmed that the immune defense reaction of the bacteria (induced by ROS) was the key factor for variations in LMW substances in the SMPs and EPS under temperature stresses.

Comparative study of technologies for extraction of biologically active substances from the raw material of animal origin

Technologies of isolation and concentration of biologically active substances, developed in the middle of the 20th century, need adjustment and adaptation to modern conditions both to increase the activity of substances and for greater economic efficiency. The aim of the research is the comparison of dynamics of biologically active compounds extraction from porcines pancreas in two methods: the saline method based on 0.9% sodium chloride solution, and the acidic method based on 2.4% trichloroacetic acid solution. Also the purpose of research is to assess the possibilities for further optimization of technologies. The total protein concentration based on the biuret reaction in the samples taken during the extraction, as well as the calculation and analysis of the point degrees and rates of extraction are chosen as the controlled parameters. Local maxima of the protein yields into the extractant media at the 60th, 135th and 255th minute were recorded during saline extraction; and at the 75th and 135th minute during acid extraction. Also the proteomic profile of the extracts was studied. Wide range of compounds with molecular weight of less than 52 kDa was found in extracts based on physiological saline solution, and protein substances of whole presented range of molecular weights in trichloroacetic acid based extracts were considered. The predominance of low molecular weight protein fraction of interest was noted also in this method of extraction in comparison with the other methods of extraction. According to the UniProt database, we assume availability of probable compounds with a molecular weight of less than 30 kDa in the purified acidic extract. The presence of some proteins absent in the final saline extract was noted. The acidic erythrograms showed a weak degrading effect of both types of extracts on the membranes of rat erythrocytes, as well as the cytoprotective effect of acidic ultrafiltrates (less than 3 kDa). The obtained results prove a better efficiency of trichloroacetic acid extraction method used for obtaining a mixture of a wide range of compounds, including biologically active substances of low molecular weight.

Рівень ендогенної інтоксикації щурів за умов експериментальної нефропатії та застосування відновленого глутатіону

The purpose of the study, therefore, was to investigate the content of substances of low and medium molecular weight, total and tyrosine-containing peptides and to assess the level of endogenous intoxication of the rat organism under conditions of experimental nephropathy and the use of reduced glutathione. Materials and methods. The experiment was performed on nonlinear white rats weighing 160-180 g. The animals were in a vivarium with a constant temperature (18-22°C), relative humidity (50-55%) in individual exchange cells in the formed groups, on a constant balanced mode of a diet with free access to water and food. Nephropathy was modeled by a single intraperitoneal injection of folic acid at a dose of 250 mg/kg. Glutathione was administered intragastrically (100 mg/kg) for 7 days after folic acid intoxication. Results and discussion. Under conditions of nephropathy in the blood serum of rats, an increase in the level of molecules of average weight was observed by 2 times, as well as low-molecular substances by 1.6 times compared with the control. Daily administration of reduced glutathione to animals with nephropathy for 7 days led to a decrease in the level of substances of medium and low molecular weight by 21% and 27% in comparison with the indicators of animals with nephropathy, but still significantly differed from the control indicators. Against the background of an increase in the content of total oligopeptides by 2.2 times in the blood serum of experimental rats, the level of tyrosine-containing peptides increased by 1.8 times in comparison with the control. The introduction of glutathione to rats with nephropathy led to a decrease in these parameters by 40 and 35%, respectively, compared with the experimental control. As a result of the established changes in the level of albumin and average weight molecules in the blood serum of animals, under conditions of nephropathy, an increase in the coefficient of endogenous intoxication was observed by 2.3 times. This imbalance indicates a violation of the processes of detoxification of endogenous metabolites in the liver of animals under conditions of nephropathy. In the groups of animals with nephropathy, which were injected with an antioxidant, the coefficient of endogenous intoxication decreased by 41% compared with animals that did not receive glutathione, but this indicator did not return to the level of control values. Conclusion. Thus, under the conditions of experimental nephropathy in the blood serum of rats, an increase in the content of total and tyrosine-containing peptides, substances of low and medium molecular weight, as well as an increase in the values of the intoxication coefficient was observed, which indirectly indicates a violation of the processes of detoxification of endogenous metabolites in the liver of experimental animals with kidney pathology. In the group of animals with nephropathy that received reduced glutathione for 7 days, only a tendency towards normalization of the studied parameters characterizing the level of endogenous intoxication under conditions of nephropathy was noted

The Poly(chloro-p-xylylene)-Ag Metal-Polymer Nanocomposites Obtained by Controlled Vapor-Phase Synthesis for SERS Effect Realisation

Substrates based on the metal-polymer nanocomposites 2,3-dichloro-p-xylylene-silver (PCPX-Ag) that realize the effect of surface-enhanced Raman scattering (SERS) were developed. To obtain nanocomposites, the vapor-phase polymerization method was used (VDP), which makes it possible to control the nanocomposite microstructure. In the process of self-assembly during VDP, nanocomposite films with inclusions of silver particles were formed on the polycore substrates. Silver content varied from 2.5 to 16% vol. The possibility of using such substrates for the detection of low-molecular substances, for example 5,5′-dithiobis- (2-nitrobenzoic acid) (DTNB) analyte, by the SERS method with an enhancement factor of up to 104, was demonstrated. The dependence of the SERS spectra enhancement on the microstructure of the nanocomposite and the silver content was determined. The optical and morphological properties of nanocomposites were also investigated and their dependence on the silver content was shown. It has been demonstrated that the nanocomposite is SERS selective since when working with complex solutions in the presence of high molecular weight substances, signal enhancement was only observed for low molecular weight substances.

Functional roles of polyamines and their metabolite acrolein in eukaryotic cells.

Among low molecular weight substances, polyamines (spermidine, spermine and their precursor putrescine) are present in eukaryotic cells at the mM level together with ATP and glutathione. It is expected therefore that polyamines play important roles in cell proliferation and viability. Polyamines mainly exist as a polyamine-RNA complex and regulate protein synthesis. It was found that polyamines enhance translation from inefficient mRNAs. The detailed mechanisms of polyamine stimulation of specific kinds of protein syntheses and the physiological functions of these proteins are described in this review. Spermine is metabolized into acrolein (CH2 = CH-CHO) and hydrogen peroxide (H2O2) by spermine oxidase. Although it is thought that cell damage is mainly caused by reactive oxygen species (O2-, H2O2, and •OH), it was found that acrolein is much more toxic than H2O2. Accordingly, the level of acrolein produced becomes a useful biomarker for several tissue-damage diseases like brain stroke. Thus, the mechanisms of cell toxicity caused by acrolein are described in this review.

ЗНАЧЕНИЕ СОДЕРЖАНИЯ ВЕЩЕСТВ НИЗКОЙ И СРЕДНЕЙ МОЛЕКУЛЯРНОЙ МАССЫ И ОЛИГОПЕПТИДОВ В ПАТОГЕНЕЗЕ ВЕТРЯНОЙ ОСПЫ

Endogenous intoxication syndrome is an important link in the pathogenesis of many infectious diseases. The role of low and medium molecular weight substances and oligopeptides acting as indicators of endogenous intoxication syndrome in the pathogenesis of varicella was studied, depending on the period of the disease, the severity of the course and the presence of complications. Based on this goal, 125 patients with varicella aged 18 to 49 years were examined. Determination of the content of substances of low and medium molecular weight in biological body fluids (blood plasma, red blood cells and urine) was carried out by the method of M. Ya.Malakhova (1995) on a spectrophotometer SF-46. The Lowru (1951) method was used to determine the level of oligopeptides in body fluids. The maximum level of substances of low and medium molecular weight was observed in patients with a complicated course of varicella during the height of the disease, as well as in patients with a severe course of the disease during the height. When determining the oligopeptides, the highest values were also obtained at the height of the disease in the severe course, as well as in the complicated course at admission. During the examination, the dependence of the studied indicators on the period of the disease, the severity, as well as the presence of complications was revealed. Thus, the most pronounced changes in the level of low and medium molecular weight substances and oligopeptides were observed in severe, and the least – in the mild course of varicella in all the studied media. In patients with developed complications, the disease was more severe, while the changes in the studied parameters were more pronounced.

Effect of thickness and build orientation on the water vapor and oxygen permeation properties of laser-sintered polyamide 12 sheets

Purpose This study aims to investigate the effect of the material thickness and build orientation on the mass transfer of low molecular weight substances through polyamide 12 (PA12) structures produced by laser sintering (LS). Design/methodology/approach Disc-shaped PA12 sheets having a nominal thickness ranging from 700 to 2,000 µm were built in horizontal, vertical and diagonal orientations and their permeation properties to oxygen and water vapor were measured. The structural properties of the sheets were examined by X-ray micro-computed tomography, differential scanning calorimetry and polarized light microscopy. Findings All the LS sheets that were investigated had water vapor and oxygen permeation coefficients that are in the range of those of PA12 produced by traditional manufacturing technologies. Despite significant differences in the porosity characteristics, the permeation properties of sheets built in different orientations were similar. The pores seem to have no measurable effect on the mass transfer rates in the sheets, and the transport processes seem to predominantly follow the rules of a regular solution-diffusion mechanism. The results showed a non-significant trend toward thickness-dependent permeation coefficients, which agrees with the observed differences in the crystal structures of the sheets. Practical implications The results are an important basis for the qualification of LS technology for direct manufacturing in applications requiring special barrier performance. Originality/value This study provides new information on mechanisms of mass transport through LS PA12 and the effect of the material thickness and build orientation. Furthermore, the results enhance understanding of the structural properties of thin polymeric sheets produced by LS.

Fabrication of an allyl-β-cyclodextrin based monolithic column with triallyl isocyanurate as co-crosslinker and its application in separation of lipopeptide antibiotics by HPLC

A novel microporous structure monolithic polymer was prepared via free radical polymerization within a stainless steel column (4.6 mm [i.d.] × 50 mm) for separation of lipopeptide antibiotics. The monolithic column was synthesized using allyl-β-cyclodextrin and methyl methacrylate as co-monomers, triallyl isocyanurate and ethylene glycol dimethacrylate as co-crosslinkers, and azobisisobutyronitrile as an initiator. The optimized monolithic columns were evaluated by scanning electron microscopy, a nitrogen absorption-desorption apparatus, and mercury intrusion porosimetry. The homemade monolithic columns not only had a relatively uniform porosity structure, low back pressure, and good permeability, but also show good separation performance. For low molecular weight substances, six aromatic compounds were separated in 6 min and the column efficiency of naphthalene achieved 35, 660 plates m−1. The enantiomers of ibuprofen and ephedrine, which were used as standard samples, were separated by the homemade monolithic column. The application potential of the monolithic column for the separation of Chinese medicine bioactive substances was illustrated by the ephedrine and pseudoephedrine, which were successfully detected in a crude extract of ephedra. Based on the excellent separation performance of the column for the aforementioned low molecular weight substances, we assumed that there are many forces, such as hydrogen bonds, π-π bonds, and dipole-dipole interactions, that are involved between enantiomers and allyl-β-cyclodextrin. Thus, natural lipopeptide antibiotics in the fermentation broth were used as samples to verify the assumption. Eighteen peaks were precisely separated from the fermentation broth. Among the 18 peaks, 4 lipopeptide antibiotics were identified by mass spectrometry. Methodologic validation was confirmed using two enantiomers of ibuprofen, and all parameters meet the testing requirements.