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Aim/objective: Corneal kindling mouse test is a model of decreasing the seizure threshold after repetitive subchronical electrical stimuli. Ketogenic diet (KD) is used for the treatment of children with pharmacoresistant epilepsy since more than 100 years. Surprisingly, very few studies testing the effect of the KD in corneal kindling test were published. The aim of this study was to evaluate the effect of the KD on the seizure activity in corneal kindling mouse model.

In the present work, we studied the interactions of three types of iron oxide nanoparticles (IONPs) with human serum albumin (HSA) by fluorescence and UV-Vis spectroscopy. The determined binding parameters of the reactions and the thermodynamic parameters, including ΔHo, ΔSo, and ΔGo indicated that electrostatic forces play a major role in the interaction of IONPs with HSA. These measurements indicate a fluorescent quenching mechanism based on IONPs-HSA static complex formation. Our study shows that the interaction between HSA and IONPs depends on the nanoparticle structure. The interaction between IONPs and HSA was found to be spontaneous, exothermic, and entropy-driven. HSA was shown to interact moderately with IONPs obtained with plant extracts of Uncaria tomentosa L. (IONP@UT) and Clinopodium vulgare L. (IONP@CV), and firmly with IONPs prepared with Ganoderma lingzhi (Reishi) extract (IONP@GL), via ground-state association. Analysis by modified Stern-Volmer approximation indicates that the quenching mechanism is static. Our study significantly improves our understanding of the mechanisms of interaction, distribution, and transport involved in the interaction between proteins and IONPs. It provides crucial insights into the functional perturbations of albumin binding capacity and the effects of IONPs on the stability and structural modifications of plasma carrier proteins.

This study focused on the ketogenic diet (KD) effects on oxidative posttranslational protein modification (PPM) as presumptive factors implicated in epileptogenesis. A 28-day of KD treatment was performed. The corneal kindling model of epileptogenesis was used. Four groups of adult male ICR mice (25-30 g) were randomized in standard rodent chow (SRC) group, KD-treatment group; SRC + kindling group; KD + kindling group (n = 10 each). Advanced oxidation protein products (AOPP) and protein carbonyl contents of brain homogenates together with differential scanning calorimetry (DSC) were evaluated. Two exothermic transitions (Exo1 and Exo2) were explored after deconvolution of the thermograms. Factor analysis was applied. The protective effect of KD in the kindling model was demonstrated with both decreased seizure score and increased seizure latency. KD significantly decreased glucose and increased ketone bodies (KB) in blood. Despite its antiseizure effect, the KD increased the AOPP level and the brain proteome's exothermic transitions, suggestive for qualitative modifications. The ratio of the two exothermic peaks (Exo2/Exo1) of the thermograms from the KD vs. SRC treated group differed more than twice (3.7 vs. 1.6). Kindling introduced the opposite effect, changing this ratio to 2.7 for the KD + kindling group. Kindling significantly increased glucose and KB in the blood whereas decreased the BW under the SRC treatment. Kindling decreased carbonyl proteins in the brain irrespectively of the diet. Further evaluations are needed to assess the nature of correspondence of calorimetric images of the brain homogenates with PPM., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The human blood plasma proteome profile has been an area of intensive investigation and differential scanning calorimetry (DSC) has come forward as a novel tool in analyzing plasma heat capacity changes to monitor various physiological responses in health and disease. This study used DSC to assess potential alterations in the plasma heat capacity profile of albumin and globulins during extremely demanding physical exercise. We monitored the changes in denaturation profiles of those plasma proteins for five consecutive days of an extraordinary exercise training schedule in 14 young male Special Forces volunteers, as well as after a 30-day recovery period. The major effect of the prolonged intense exercise was the continuous upward shift of the albumin peak by 2°-3 °C on the initial days of exercise, with a tendency to plateau circa the 5th day of exercise. In addition, some redistribution of the denaturational enthalpy was observed upon exercise, where the globulins peak increased relative to the albumin peak. Noteworthy, the alterations in the plasma proteome denaturational profiles were not persistent, as virtually full recovery of the initial status was observed after 30 days of recovery. Our findings indicate that 5 days of exhaustive physical exercise of highly trained individuals enhanced the thermal stability of plasma albumin shifting its denaturational transition to higher temperatures. We surmise that these effects may be a result of increased blood oxygenation during the prolonged intense exercise and, consequently, of albumin oxidation as part of the overall adaptation mechanisms of the body to extreme physical and/or oxidative stress., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Tissue engineering demands the development of scaffolds that mimic natural extracellular matrices (ECM). Despite the success in obtaining synthetic interstitial ECM, the production of an artificial basement membrane (BM), the specialized thin sheet of ECM that is pivotal for the functional organization of most tissues and internal organs, is still not achieved. With the long-term aim of developing a flat BM-like structure here we investigated the behavior of acid-soluble Col IV during simultaneous assembly with laminin (LM) in acidic conditions. The underlying rationale was the previously observed phenomenon of acid-triggered LM polymerization, giving rise to biomimetic polylaminin (polyLM) that can be adsorbed on the substrate. Unexpectedly, we found that Col IV (that does not polymerize in acidic conditions) readily incorporated into the polyLM layer, forming a network that mimics to a great extent the characteristic polygonal morphology of single polyLM observable at micrometric scale. Scanning calorimetry and light scattering measurements supported the notion that polyLM and Col IV could directly interact. The biological properties of the proposed artificial BM-like structure were characterized using human keratinocytes (HACAT) and umbilical vein endothelial cells (HUVEC). HACAT formed stratified cell layers on the hybrid polyLM/Col IV layer, but not on Matrigel, nor on LM or Col IV alone, while HUVEC improved cortical F-actin and tight juctions organization on polyLM/Col IV. Thus, the proposed artificial BM reproduces not only morphological but also some functional properties of the natural BM. STATEMENT OF SIGNIFICANCE: Basement membranes (BMs) are flat biological matrices separating tissue compartments in the body. Their peculiar sheet-like structure is thought to result from the association of two independent protein networks of laminin and collagen IV. While pursuing the development of an artificial BM, we found that, when mixed with acid-induced polymerized laminin, collagen IV immediately conformed to the laminin shape. This implies that the protein networks may not be independently assembled as believed so far, but instead that laminin may command the assembly of collagen IV. Our hybrid matrix was structurally more stable than the commercial BM extract Matrigel and, unlike the latter, supported in vitro formation of a stratified layer of keratinocytes that approximated the organization of the natural epidermis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

In this work, we examined by DSC protein denaturation heat capacity profiles for two body fluids, cerebrospinal fluid (CSF) and blood plasma obtained from brain tumor (mainly glioblastoma) patients and healthy volunteers. We observed large distinctions between the heat capacity profiles of CSF and blood plasma, although their protein compositions are believed to have much in common. A prominent, previously unreported CSF feature was the existence of a pre-denaturation exothermic transition peaking at ~ 50-52 °C, recorded for both control and brain tumor CSF. This appears to be the first observation of a pre-denaturation exotherm in a human body fluid. In all studied samples, the exotherms deconvoluted with high precision into a sum of two Gaussian peaks. These exotherms are apparently specific, originating from brain tissue-soluble proteins in the CSF not present in blood plasma. Malignant brain tumors (glioblastoma multiforme, Grade IV, and low-grade glioma, Grade II) reduced twofold the enthalpy of the exotherms relative to the control. These results suggest that the amount and/or conformational state of the CSF proteins (e.g., intrinsic disorder) giving rise to pre-denaturation exothermic events substantially changed upon brain tumor progression. Concomitantly, the enthalpy of the CSF endothermic peaks was partially redistributed from a lower-temperature (main) transition to a higher-temperature transition. The presented data demonstrated that the heat capacity profiles of intrinsic CSF proteins constitute a sensitive biomarker of glioblastoma and other brain malignancies.

The effects of thioridazine (TDZ) and chlorpromazine (CPZ) and bovine serum albumin nanoparticles (BSA-NPs) on erythrocyte membranes have been investigated. Two kinds of hemolytic assays were used; hemolysis under hypotonic conditions and hemolysis in physiological conditions. Under hypotonic conditions for 50% hemolysis, both TDZ and CPZ have a biphasic effect on membranes; namely, stabilization at low concentrations and destabilization after reaching a critical concentration. In physiological conditions, there are other critical concentrations above which both drugs hemolyse the erythrocites. In each case, the critical concentrations of TDZ are lower than those of CPZ, which is consistent with the ratio of their partition coefficients. When BSA-NPs are added to the erythrocyte suspension simultaneously with the drugs, the critical concentrations increase for both drugs. The effect is due to the incorporation of a portion of drug substances into the BSA-nanoparticles, which consequently leads to the decrease of the active drug concentrations in the erythrocyte suspension medium. Similar values of the critical concentrations are found when the BSA-NPs are loaded with the drugs before their addition to the erythrocyte suspension in which case the events of the partition are: desorption of the drug from BSA-NPs, diffusion through the medium, and adsorption on erythrocyte membranes. This result suggests that the drugs are not influenced by the processes of adsorption and desorption onto and out of the BSA-NPs, and that the use of BSA-NPs as drug transporters would allow intravenous administration of higher doses of the drug without the risk of erythrocyte hemolysis.

The data presented in this article are related to the research article entitled "Cubic phases in phosphatidylethanolamine dispersions: formation, stability and phase transitions " (Tenchov and Koynova, 2017) [1]. This article presents thermodynamic data obtained by differential scanning calorimetry following the evolution of the L α - H II endotherm upon temperature cycling during the lamellar to cubic phase conversion.

Introduction: Although considerable efforts have been made to develop effective therapeutic agents for Alzheimer's Disease (AD), neither a consensus concerning the pathogenesis of the disease nor a successful therapy for its treatment is yet available. The natural product chemistry brings tremendous diversity and abundant resource for medical needs., Objectives: The present review summarizes recent patents on natural extracts and derived drugs as agents for the prevention and treatment of AD. It also sums up the suggested mechanisms of action of the formulated natural remedies., Conclusion: It is now becoming well accepted that multiple factors contribute to the progression of AD. The pathogenesis of the disease involves amyloid-β cascade, tau hyperphosphorylation, oxidative stress, inflammation, mitochondrial dysfunction, protein misfolding, gene mutation, etc. It has been suggested that the multifactorial nature of AD pathogenesis requires the design of medicines with a wide spectrum of activity. Medicinal herbs are known to consist of multiple compounds and may implicate multiple mechanisms, thus being advantageous over the simple single-target drugs in the treatment of complex diseases. Indeed, natural products attract increased attention. In the last decades, they have become a major focus in the quest for AD remedies and may represent a real promise for curing the disease., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Differential scanning calorimetry was applied to evaluate the efficacy of preventive treatments with biologically active compounds of plant origin against neurodegenerative disorder in mice. As we reported recently, large differences exist between the heat capacity profiles of water-soluble brain proteome fractions from healthy animals and from animals with scopolamine-induced dementia: the profiles for healthy animals displayed well expressed exothermic event peaking at 40-45°C, by few degrees above body temperature, but still preceding in temperature the proteome endothermic denaturational transitions; the low-temperature exotherm was completely abolished by the scopolamine treatment. Here we explored this signature difference in the heat capacity profiles to assess the efficacy of preventive treatments with protectant drugs anticipated to slow down or block progression of dementia (myrtenal, ellagic acid, lipoic acid and their combinations, including also ascorbic acid). We found that these neuroprotectants counteract the scopolamine effect and partially or completely preserve the 'healthy' thermogram, and specifically the low-temperature exotherm. These results well correlate with the changes in the cognitive functions of the animals assessed using the Step Through Test for learning and memory. The exothermic event is deemed to be associated with a reversible process of fibrillization and/or aggregation of specific water-soluble brain protein fractions preceding their denaturation. Most importantly, the results demonstrate that the effect of scopolamine and its prevention by protectant substances are clearly displayed in the heat capacity profiles of the brain proteome, thus identifying DSC as a powerful method in drug testing and discovery., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The non-lamellar phases formed by membrane lipids in diluted aqueous dispersions are mainly represented by the inverted hexagonal phase, HII, and phases of cubic symmetry, among them the bicontinuous cubic phases Pn3m (Q 224 ), Im3m (Q 229 ) and Ia3d (Q 230 ). Here we report X-ray diffraction data on phosphatidylethanolamine (PE) dispersions forming highly stable Im3m and Pn3m cubic phases at ambient temperature as a result of a temperature cycling through the Lα - HII transition and complement the structural characterization of the PE phase transitions with thermodynamic data obtained by differential scanning calorimetry and differential scanning densitometry. All studied PEs displayed irreversible two-state Im3m → Pn3m phase transitions in the range ∼75-85°C with enthalpy of ∼100cal/mol. By contrast with the Lα - HII transition, the Im3m → Pn3m transition was not accompanied by a stepwise change of the specific volume. The cubic phases induced in dipalmitoleoyl PE dispersions are of particular interest because of their facile formation, especially in the presence of small amounts of charged lipid admixtures, and long-term stability at physiologically relevant conditions in a broad temperature range around room temperature., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In the present work we combine spectroscopic, DSC and computational approaches to examine the multiple extracellular Glu mutants E204Q/E194Q, E204Q/E194Q/E9Q and E204Q/E194Q/E9Q/E74Q of bacteriorhodopsin by varying solvent ionic strength and composition. Absorption spectroscopy data reveal that the absorption maxima of multiple EC Glu mutants can be tuned by the chloride concentration in the solution. Visible Circular dichroism spectra imply that the specific binding of Cl- can modulate weakened exciton chromophore coupling and reestablish wild type-like bilobe spectral features of the mutants. The DSC data display reappearance of the reversible thermal transition, higher Tm of denaturation and an increase in the enthalpy of unfolding of the mutants in 1 M KCl solutions. Molecular dynamics simulations indicate high affinity binding of Cl- to Arg82 and to Gln204 and Gln194 residues in the mutants. Analysis of the experimental data suggests that simultaneous elimination of the negatively charged side chain of Glu194 and Glu204 is the major cause for mutants' alterations. Specific Cl- binding efficiently coordinates distorted hydrogen bonding interactions of the EC region and reconstitutes the conformation and structure stability of mutated bR in WT-like fashion., Competing Interests: The authors have declared that no competing interests exist.

Lipid aggregates have been used as drug carriers for several decades. Recently, nonlamellar liquid crystalline lipid systems have attracted attention as possible drug-delivery vehicles because of their unique nanostructure and physicochemical properties. Here we summarize data on the nonlamellar phase-forming propensity of the cationic phosphatidylcholines (cationic PCs). The class of cationic PCs has been specifically designed and explored for the purpose of nonviral gene delivery. These lipids were found to comprise an attractive cationic lipid class because they are biodegradable, have low toxicities, and in a number of cases, display high transfection activity. Lipids of this class form a variety of polymorphic and mesomorphic phases-lamellar and nonlamellar, depending on the structure of their hydrocarbon chains and especially on the third hydrocarbon chain used to alkylate the PC phosphate group and convert the zwitterionic PC headgroup into a cation. Here we characterize the phase behavior and transfection activity of eight cationic PCs that have been identified as forming nonlamellar phases-inverted hexagonal and cubic. We then demonstrate that those cationic PCs that also form nonlamellar lipoplexes are notably less efficient gene nanocarriers in comparison with the cationic PCs forming lamellar phase lipoplexes.

From their discovery half a century ago and the subsequent appreciation of their clinical utility, liposomes currently hold a recognized position in the mainstream of drug delivery systems. Conventional techniques for liposome preparation and size reduction are simple to implement and do not require sophisticated equipment. However, most of them are not easy to scale-up for industrial liposome production. With several liposomal formulations already on the market, and more in final clinical trials, the industrial scale production of liposomes has become reality, and so the range of liposome preparation methods has been extended by a number of techniques which are increasingly attractive, such as microfluidic hydrodynamic focusing, supercritical fluid processing, freeze-drying and spray-drying. Some of these new techniques generally represent advancements of the conventional methods allowing for scale-up, better reproducibility and process control. This review summarizes patents in the last decade offering new techniques for production of liposomes as related to their application in drug delivery.