Chlorpromazine effect on lysozyme-lipid interactions

Despite considerable research efforts, the molecular mechanisms of anaesthetic action still remain the matter of extensive debates. According to one viewpoint, anaesthetics alter the properties of lipid bilayer which, in turn, affects the functions of embedded membrane proteins. In contrast, protein-based theories of anaesthetic action postulate that the drugs modulate the functions of membrane proteins through direct association. To develop a unique conception of anaesthesia further in-depth investigations of drug-membrane interactions are strongly required. In the present work a well-known fluorescent probe pyrene has been employed to gain molecular insights into the interactions between amphipathic phenothiazine derivative chlorpromazine (CPZ) and model membranes composed of cationic globular protein lysozyme (Lz), and lipid vesicles prepared from zwitterionic lipid phosphatidylcholine (PC) and its mixtures with anionic lipid cardiolipin (CL) in the molar ratios 19:1, 9:1 and 4:1. To give unambiguous interpretation of the drug effect on protein-lipid interactions, we first analyzed the changes in pyrene excimerization due to the formation of either CPZ-lipid or Lz-lipid complexes. Pyrene excimer-to-monomer intensity ratio (E/M), a parameter which reflects the alterations in membrane free volume, was found to decrease upon Lz or CPZ binding to the lipid vesicles. Apparently, embedment of the protein and drug molecules into the hydrophobic region of lipid bilayer gives rise to the increase in lipid packing, decrease in the rate of trans-gauche isomerization of the lipid acyl chains and, consequently, reduction of membrane free volume. At the next step of the study, we analysed the changes in the rate of pyrene excimerization upon Lz addition to drug-lipid mixtures. In CL-containing liposomes the presence of CPZ does not modify the magnitude and sign of protein effect on membrane free volume. This implies that CPZ is incapable of perturbing Lz structure and exerted no influence on the protein interactions with this kind of liposomes. In contrast, in PC vesicles E/M ratio appeared to increase upon lysozyme binding to CPZ-modified model membranes. This finding may be explained in terms of two possibilities: (i) CPZ induces the formation of the new Lz conformer whose interactions with lipid bilayers are accompanied by the increase in membrane free volume; (ii) CPZ imparts the positive charge to the lipid bilayer thereby preventing Lz penetration into hydrophobic membrane region. Interfacially-located protein molecules are likely to generate structural defects coupled with the increased bilayer free volume. The results presented here clearly demonstrate that membrane composition can modulate the drug action on lipid-protein interactions. The recovered difference between CPZ effect on Lz-lipid binding in PC and CL-containing bilayers provide support to the idea that membrane environment can stabilize certain protein conformations differing in their responsiveness to drug action

The nature of compensatory and restorative processes in the livers of animals irradiated during hypokinesia

The nature of postirradiation repair in the livers of rats irradiated during hypokinesia is investigated. Hepatocyte population counts, mitotic activity, binuclear cell content, and karyometric studies were done to ascertain the effects of combined hypokinesia and radiation. Hypokinesia is shown to change the nature and rate of post-irradiation changes in the liver, the effect varying with the timing of irradiation relative to the length of hypokinesia. It is concluded that the changes in the compensatory and restorative processes are caused by stress developed in response to isolation and restricted mobility. By changing neuroendocrine system activity, the stress stimulates cell and tissue repair mechanisms at a certain stage essential to the body's reaction of subsequent irradiation

Lipid-mediated lysozyme aggregation: furster resonance energy transfer study

Aggregation of proteins into insoluble complexes is intimately linked to pathogenesis of several neurodegenerative diseases. Protein aggregation is commonly regarded as nonspecific coagulation of incompletely folded or partially denaturated polypeptides, driven by interaction between the exposed hydrophobic patches. Accumulating evidence indicates that protein self-association can be induced by protein-lipid interactions. The present study addresses a problem of aggregation behavior of lysozyme (Lz) bound to model membranes composed of phosphatidylcholine (PC) and phosphatidylglycerol (PG) (8:2). The formation of Lz assemblies in lipid environment has been monitored by measuring steady-state resonance energy transfer (FRET). Several donor-acceptor pairs have been employed: tryptophan (Trp) – pyrene, pyrene – fluorescein 5’-isothiocyanate (FITC) and FITC – rhodamine-isothiocyanate (RITC). Fluorescence spectra of pyrene maleimide-labelled Lz (Lz-PM) recorded at different lipid-to-protein molar ratios (L:P) with excitation wavelength of 296 nm were featured by three bands corresponding to Trp, pyrene monomer and excimer emission. Analysis of the shape of emission spectra showed that the ratio of PM to Trp intensity rises with increasing Lz-PM concentration and decreasing L:P values from 379 to 77. This effect is most probably to arise from the enhanced FRET between Trp and pyrene. The finding that the magnitude of this effect depends on protein concentration suggests that FRET enhancement is caused by the formation of protein aggregates. The same result was obtained with Lz- attached pyrene as donor and Lz-attached FITC as acceptor – the efficiency of energy transfer increased with increasing total protein concentration and decreasing L:P. Notably, the most pronounced increase of energy transfer efficiency was observed at surface coverage ca. 38 lipids per one protein molecule suggesting that this L:P value is critical for formation of Lz self-associates. The assumption that Lz forms aggregates in membrane environment is also corroborated by the quantitative analysis of FRET between FITC and RITC. The distance between FITC and RITC was found to be ca. 8 nm which exceeds the dimensions of Lz molecule by 2-2.5 times, lending additional support to the idea about Lz self- association in lipid surroundings

Формування механізму реалізації державної фінансової політики в Україні

EN:Financial system was considered as an integration factor of aggregated elements of state economic system that provides accumulative property of financial resources and their mobility between subjects. This is possible, when the influence of financial policy of the state is taken out. As it defines the objective tendencies of growing share of the financial sector contribution to the gross domestic product, which drives the redistribution within the financial system funds involved in the form of foreign borrowing and foreign investment. It has been proved that an alternative model of development for implementation of financial policy of the state in the context of the financial system and the economic factors functioning provides optimal cost distribution of financial resources between businesses, households, industries, regions, and financial intermediaries. Designing the integrated approach to development for implementation of financial policy of the state’s distribution of budget transfers between entities of the financial system focused on corporate governing the financial resources, and is a common feature of the integrated aggregated elements of economic system. The mechanism of the financial system operation is considered as a set of tools for designing the strategic regulation, planning, financing and managing financial flows. This made ground for methodic support to the research and its meaningful component of financial support by the state and the impact of potential financial risks on the formation of alternative distribution and use of financial resources between entities on financial market. The elements of financial relations at the state level were segregated to create conditions for placing its own debt on the stock market, to attract resources to finance budget expenditures and debt management. It is suggested to consider fiscal policy as part of the implementation of financial policy of the state in the short term, aimed at the redistribution of the gross domestic product due to tax system, budget expenditure and social transfers. In the long run, fiscal policy should help boost economic development of the state through discretionary changes in economic stabilizers and regulators, thus providing a multiplier effect leveling the result of internal displacement lag and budget shortage. UK:Стаття присвячена обґрунтуванню засад формування та реалізації державної фінансової політики в Україні. Розглянуто фінансову систему як фактор інтеграції сукупних елементів економічної системи держави, який забезпечує акумулятивну властивість фінансових ресурсів та їх мобільність між суб’єктами. Розкрито механізм функціонування фінансової системи та обґрунтовано методичну складову формування державної фінансової підтримки. Виокремлено елементи фінансових відносин на державному рівні для формування умов розміщення власних боргових зобов’язань на фондовому ринку, залучення ресурсів для фінансування видатків бюджету, а також управління державним боргом. Запропоновано розглядати бюджетно-податкову політику як складову реалізації державної фінансової політики в короткостроковому періоді, спрямовану на перерозподіл валового внутрішнього продукту за системою оподаткування, бюджетних витрат та соціальних трансфертів. В довгостроковому періоді бюджетно-податкова політика повинна сприяти зростанню економічного розвитку країни через дискреційні зміни економічних стабілізаторів та регуляторів, забезпечуючи таким чином ефект мультиплікатора, нівелюючи ефект витіснення внутрішнього лагу, дефіцит бюджету

Evaluation of hemodynamics during the formation of the anastomosis during renal transplantation

Samara State University, The 6th International Medical Congress for Students and Young Doctors, May 12-14, 2016Introduction. Today, the need for kidney transplantation has increased steadily. As we all know is impossible without transplantation of the donor organ Number of young patients is steadily growing, growing and having a history of infection transmessivnye. Currently, patients need to provide this type of aid is satisfied by 17 %. One solution to this problem is to use maximum pool of deceased donors as a resource for getting kidney.Optimize transplantation technique. Forming an anatomically correct arterial anastomosis during renal transplantation - one of the ways of such optimization. The aim is to explore options for the anatomy of the iliac artery graft ( branch sheathe iliac artery), is used to evaluate the possible options for their use in the revascularization of renal graft using computational methods hemodynamics. Materials and methods 1. Morphological stage of work was performed on the anatomical material ( 35 cases) Otpreparovannye materials PPA branches covered antialiasing powder scanned using 3D - Scanner Solutionix Rex Scan 3c post-processing in the application Leos.diametr utochnalsya vessels using morphometry. The resulting transformed polygonal model - optimized polygonal structure, reduced the number of polygons in Autodesk Maya application. 2. Radiological profile of the work carried out on the basis of the regional archive medical images of the Samara region. The study selected studies of the abdomen and pelvis without pathology of blood vessels made with intravenous contrast. Total produced 75 studies. DICOM data reconstruction was carried out with the help of the product BEAM-C, developed by a team of Samara State Medical University in the framework of the work under a state contract 3.The data loaded into the anatomy Flow Vision application (OOO "Tesis", Moscow) Hemodynamic parameters were calculated using the "Breeze" computing cluster SSMU (14 teraflops) Results.The results of variant anatomy of the iliac arteries match ADACHI classification (1926) for the AL Talawah-Soames Three-dimensional models of all variants of the anatomy of the iliac arteries and performed their anastamozirovanie virtual models of renal bed. The findings of various embodiments of forming anastomoses allow appreciated that embodiments VPA relevant in predicting the blood flow volume in the graft. In the case of option I, IIA, IIB, IIIA options WPA uses for the formation of arterial anastomosis is a good prognostic value. In other cases, the more favorable is the use of the PPA to form an anastomosis. Conclusions. Using options vascular structure is important in the choice of ways to revascularization of renal graft. Necessary clinical data evaluation computer hemodynamics. Virtual modeling vascular reconstruction in this zone can be effective in determining the affinity of therapeutic strategies

Hemoglobin binding to phospholipid membranes as revealed by pyrene fluorescence study

In this work hemoglobin (Hb) association with lipid bilayers was investigated using fluorescent probe pyrene. Model membranes were prepared from zwitterionic lipid phosphatidylcholine (PC), anionic lipid phosphatidylglycerol (PG) and cholesterol (Chol). Hb-lipid binding was followed by the pyrene fluorescence quenching. Hb-induced decrease of pyrene monomer fluorescence was followed by the increase of relative intensities of vibronic bands. Presumably, Hb penetration into the bilayer increases the space between neighbouring lipids and promotes water penetration into the membrane core. Pyrene excimer emission quenching was interpreted in terms of resonance energy transfer. The greatest depth of Hb penetration into the lipid bilayer was observed in PC vesicles. In Chol-containing liposomes sterol condensing effect prevents deep protein penetration into the membrane. PG has an ability to stabilize lipid bilayers due to the ordered state of its lipid tails and H-bonding interactions between lipid molecules. This also can prevent Hb access to the inner membrane regions

Resonance energy transfer study of hemoglobin binding to model lipid membranes

In the present study fluorescence resonance energy transfer (FRET) technique was employed to obtain the information about the structure of hemoglobin (Hb) complexes with model lipid membranes of different composition. For this purpose three membrane probes, 3-methoxybenzanthrone (MBA), 4- dimethylaminochalcone (DMC) and 6-propionyl-2-dimethylaminonaphthalene (Prodan) were assessed as possible donors for heme moiety of the protein. Model membranes were composed of zwitterionic lipid phosphatidylcholine (PC), anionic lipid cardiolipin (CL) and cholesterol (Chol). FRET measurements were interpreted in terms of the model of energy transfer in two-dimensional systems proposed by Fung and Stryer and further extended by Davenport et al. No FRET was observed between Prodan and Hb because Prodan under the employed experimental conditions was not distributed into the lipid bilayer. In the case of DMC, Hb-induced oxidative processes in the lipid phase hampered the estimation of Hb location in a lipid bilayer. Therefore, structural analysis of Hb-lipid complexes was carried out using MBA as a donor. First, the donor quantum yield, Fцrster radii and fluorescence anisotropy of the probes have been measured. Second, the amount of Hb bound to model membranes was estimated in terms of the lattice models of large ligand adsorption to lipid bilayers allowing for the possibility of protein insertion into membrane interior. Finally, the distance from acceptor plane to the bilayer center and the depth of Hb penetration into lipid bilayer were calculated. It was assumed that protein binds to membranes in the form of dimers and penetrates into the membrane interior. In neutral liposomes Hb penetrates only to the depth of lipid headgroups. The observed higher extent of Hb penetration into Chol containing bilayer as compared to PC liposomes may be a consequence of specific Hb-Chol interaction. In the case of PC/CL liposomes Hb was found to insert in the non-polar membrane region. Taking into account the possibility of forming the inverted hexagonal structures in the presence of CL, it cannot be excluded that Hb being entrapped in such structures, translocates through the membrane. If this phenomenon takes place, deeper Hb penetration into lipid bilayer might be expected. The obtained results can be useful for exact characterization of Hb binding to the membranes

Influence of oligomeric and fibrillar lysozyme on physical properties of model membranes

A pathological hallmark of more than 20 human diseases including Alzheimer’s disease, Parkinson’s disease, type II diabetes is the deposition in organs and tissues of insoluble highly ordered protein aggregates, called amyloid fibrils. It is becoming widely recognized that toxicity of amyloid species is related to their interactions with cell membranes. In the present study we focused our efforts on the examination of the influence of amyloid fibrils and their precursors (oligomeric aggregates) of lysozyme on the structural and physical properties of the model membranes composed of phosphatidylcholine and its mixture with cholesterol. For evaluating the extent of lipid bilayer modifications, we used fluorescence spectroscopy technique. The results of pyrene excimerization measurements showed that amyloid protein reduces membrane fluidity. Analysis of Laurdan emission spectra revealed the ability of lysozyme aggregates to produce bilayer dehydration. The most pronounced membrane-modifying effects were observed in the case of oligomeric lysozyme. Significantly less influence of pathogenic protein aggregates on the physical properties of cholesterol-containing vesicles confirmed the hypothesis on the preventive role of cholesterol in amyloid-related diseases

Lipid bilayer modification induced by fibrillar lysozyme: fluorescence spectroscopy study

The correlation between neurodegenerative diseases (Parkinson’s, Alzheimer’s diseases), type II diabetes, systemic amyloidosis, etc. and deposition of protein aggregates in brain and other tissues has long been established. A growing body of evidence has demonstrated that binding of amyloid proteins to the membrane may underlie their cytotoxic effect. It was shown that amyloid toxicity arises primarily from a soluble oligomeric form (pre-fibrillar aggregates) of the peptide rather than amyloid monomers or mature fibrils. The molecular basis of the amyloid protein toxicity is not sufficiently clear and requires further investigation. In view of this, the present study has been undertaken to ascertain the effect of fibrillar aggregates of lysozyme on the structural and physical properties of model membranes (liposomes) composed of zwitterionic lipid phosphatidylcholine and its mixture with cholesterol (30 mol%). To this end, two fluorescent probes with different properties and bilayer location, pyrene and Laurdan, have been employed. Pyrene spectra have characteristic vibronic structure in the region of 370-400 nm. Relative intensities of vibronic transitions exhibit dependence on solvent polarity. Excited species of pyrene can interact with non-excited ones thus forming excited state dimers – excimers. Excimer-to-monomer fluorescence intensity ratio reflects the extent of pyrene excimerization, which depends mainly on the rate of monomer lateral diffusion in lipid bilayer, being a function of the density of lipid molecular packing. Analysis of pyrene emission spectra revealed the absence of any influence of fibrillar lysozyme on the structural state of bilayer acyl chain region. Laurdan is an amphiphilic fluorescent probe, whose emission spectra are sensitive to the environmental polarity (hydration level). In the solvents of high polarity, Laurdan shows a considerable shift of its emission spectrum to longer wavelengths due to the dipolar relaxation processes. The changes in the emission spectrum of Laurdan were characterized by the generalized polarization value (GP). In all types of liposomes increasing concentration of fibrillar lysozyme resulted in the increment of GP, suggesting that amyloid fibrils cause the decrease in the lipid bilayer polarity