Neuroprotective Effect of the Neuropeptide Cycloprolylglycine Depends on AMPA- and TrkB-Receptor Activation

Previously, we have shown that the endogenous neuropeptide cycloprolylglycine (CPG) is the positive modulator of AMPA receptors and revealed the dependence of its anxiolytic and antihypoxic action on BDNF/Trk signaling. In the present work, we for the first time conducted in vitro experiments using the AMPA receptor blockers DNQX and GYKI 52466 and the Trk receptor blocker K252a. It is shown that the neuroprotective effect of CPG depends on the activation of both AMPA and Trk receptors.

Determination of the quantitative content of chlorophylls in leaves by reflection spectra using the random forest algorithm

Determining the quantitative content of chlorophylls in plant leaves by their reflection spectra is an important task both in monitoring the state of natural and industrial phytocenoses, and in laboratory studies of normal and pathological processes during plant growth. The use of machine learning methods for these purposes is promising, since these methods allow inferring the relationships between input and output variables (prediction model), and in order to improve the quality of the prediction, a researcher may modify predictors and selects a set of method parameters. Here, we present the results of the implementation and evaluation of the random forest algorithm for predicting the total concentration of chlorophylls a and b from the reflection spectra of plant leaves in the visible and infrared wavelengths. We used the reflection spectra for 276 leaf samples from 39 plant species obtained from open sources. 181 samples were from the sycamore maple (Acer pseudoplatanus L.). The reflection spectrum represented wavelengths from 400 to 2500 nm with a step of 1 nm. The training set consisted of the 85 % of A. pseudoplatanus L. samples, and the performance was evaluated on the remaining 15 % samples of this species (validation sample). Six models based on the random forest algorithm with different predictors were evaluated. The selection of control parameters was performed by cross-checking on five partitions. For the first model, the intensity of the reflection spectra without any transformation was used. Based on the analysis of this model, the optimal ranges of wavelengths for the remaining five models were selected. The best results were obtained by models that used a two-point estimation of the derivative of the reflection spectrum in the visible wavelength range as input data. We compared one of these models (the two-point estimation of the derivative of the reflection spectrum in the range of 400-800 nm with a step of 1 nm) with the model by other authors (which is based on the functional dependence between two unknown parameters selected by the least squares method and two reflection coefficients, the choice of which is described in the article). The comparison of the results of predictions of the model based on the random forest algorithm with the model of other authors was carried out both on the validation sample of maple and on the sample from other plant species. In the first case, the predictions of the method based on a random forest had a lower estimate of the standard deviation. In the second case, the predictions of this method had a large error for small values of chlorophyll, while the third-party method had acceptable predictions. The article provides the analysis of the results, as well as recommendations for using this machine learning method to assess the quantitative content of chlorophylls in leaves.

Angiogenic Effects of Anxiolytic Fabomotizole

In vitro experiments performed on an isolated human endothelial HUVEC cell culture showed that the anxiolytic fabomotizole, which, in addition to the anxiolytic effect, has neuroprotective and cardioprotective activities largely associated with its agonistic action on sigma-1 receptors and shows a pronounced angiogenic activity. Fabomotizole angiogenic activity is realized in the range concentration from 10-5 to 10-8 M and is doze-dependent. In the literature, data on the presence of angiogenic activity in sigma receptor agonists have not been previously reported.

Dipeptide Mimetics of Different NGF and BDNF Loops Activate PLC-γ1

Previously, we designed and synthesized dipeptide mimetics of individual loops of the nerve growth factor (NGF) and the brain-derived neurotrophic factor (BDNF). It was shown that these mimetics activate the corresponding tyrosine kinase (Trk) receptors and have different patterns of activation of the PI3K/AKT and MAPK/ERK postreceptor signaling pathways in vitro. In the present study, it was shown on HT-22 cells that all these compounds activate the phospholipase C-γ1 (PLC-γ1) cascade.

A system approach to the modeling of fungal infections of the wheat leaf

Currently, studies on the mechanisms of the pathogenesis of plant diseases and their distribution in crops are intensively conducted in Russia and the world. First of all, this interest is associated with a significant effect of pathogens on the harvest. In Western Siberia, brown rust and powdery mildew are almost annually recorded in the crops of spring and winter wheat, reaching in some years up to the epiphytotic level. In this regard, methods for monitoring the condition of crops in order to predict their dynamics and plan agrotechnological events to control the state of plants in crops, including the development of fungal infection are developing. Models of fungal infections development on the wheat leaf (for example, brown rust) are used to monitor, predict and control the state of crops in order to optimize the growing process. Mathematical models allow computational experiments to make predictions about the risk dynamics of infections in different scenarios of global weather changes. Such designation of models assumes their hierarchical structure characteristic of multilevel modeling systems. This review presents models for the development of foliar fungal infections in crops, and formulates the methodological aspects of system modeling that can be used for adapting existing models and their units, and developing new models based on them. The article presents the structure of the hierarchical system for modeling the development of leafy infection, provides an overview of the units constituting the system, and discusses the issues of parametric adaptation of submodels. We demonstrated that, to date, plant growth and development models have been developed with varying degrees of detail. Currently, to develop a system for modeling the development of an infection in a crop, it is necessary to determine a large body of available experimental data and, by taking into account this data, we can put together a model as a system consisting of model modules, for which the models of basic processes have already been developed and described.

Analysis of the Basic Characteristics of Osteogenic and Chondrogenic Cell Lines Important for Tissue Engineering Implants

We isolated and characterized cultures of bone and cartilage tissue cells of laboratory minipigs. The size and morphological features of adherent osteogenic and chondrogenic cells were specified. During long-term culturing under standard conditions, the studied cultures expressed specific markers that were detected by immunohistochemical staining: alkaline phosphatase and calcium deposits in osteoblasts and type II collagen and cartilage extracellular matrix in chondrogenic cells. Proliferative potential (mitotic index) of both cell types was 4.64% of the total cell number. Cell motility, i.e. the mean velocity of cell motion was 49 pixels/h for osteoblasts and 47 pixels/h for chondroblasts; the mean migration distance was 2045 and 2118 pixels for chondroblasts and osteoblasts, respectively. The obtained cell lines are now used as the control for evaluation of optimal biocompatibility of scaffold materials in various models. Characteristics of the motility of the bone and cartilage tissue cells can be used for modeling and estimation of the rate of cells population of 3D scaffolds made of synthetic and biological polymers with different internal structure and physicochemical properties during designing in vitro tissue implants.

Angiogenic Effects of Dimeric Dipeptide Mimetic of Loop 4 of Nerve Growth Factor

Angiogenic action of compound GK-2, a dimeric dipeptide mimetic of loop 4 of nerve growth factor (NGF), was studied in in vitro and in vivo experiments. Experiments on human endothelial cell culture HUVEC showed that compound GK-2 significantly (p<0.05) stimulated the initial stage of angiogenesis, and its angiogenic activity was not inferior to the reference neurotrophin NGF. In experiments with hindlimb ischemia modeled in rats, GK-2 (1 mg/kg intraperitoneally for 14 days) significantly increased the total length of capillary vessels (p<0.003) and the number of vessels per 1 mm2 ischemic tissue (p<0.001) in comparison with the control. Our findings indicate that under experimental conditions compound GK-2 exhibits not only angiogenic, but also anti-ischemic activity.

Dipeptide Piracetam Analogue Noopept Improves Viability of Hippocampal HT-22 Neurons in the Glutamate Toxicity Model

Effect of noopept (N-phenylacetyl-prolylglycine ethyl ester) on viability of neurons exposed to neurotoxic action of glutamic acid (5 mM) was studied in vitro in immortalized mouse hippocampal HT-22 neurons. Noopept added to the medium before or after glutamic acid improved neuronal survival in a concentration range of 10-11-10-5 M. Comparison of the effective noopept concentrations determined in previous studies on cultured cortical and cerebellar neurons showed that hippocampal neurons are more sensitive to the protective effect of noopept.

[Studying in vitro neuroprotective properties of GK-2(h)--a new original mimetic of human nerve growth factor]

Human nerve growth factor (NGF) mimetic hexamethylenediamide bis-N-monosuccinyl-glicyl-lysine) (GK-2(h)) demonstrates protective activity on immortalized mouse hippocampal cell line HT22 in a concentration up to 10(-13)M against hydrogen peroxide toxicity and in concentration up to 10(-8) M against glutamate toxicity. GK-2(h) dipeptide protects rat PC-12 pheochromocytoma cells in a concentration up to 10(-7) M and protects human neuroblastoma SH-SY5Y cells in a concentration up to 10(-8) against 6-hydroxydofamine-induced damage.

[Neuroprotective effects of a dipeptide mimetic on the GK-2 nerve growth factor in model of permanent common carotid artery occlusion in rats]

The behavioral and biochemical effects of a new dipeptide mimetic of the GK-2 nerve growth factor (NGF) have been studied on a model of chronic cerebral ischemia induced by permanent common carotid artery occlusion in rats. It is established that subchronic intraperitoneal injections of GK-2 (0.5 mg/kg) 4 h after surgery, followed by seven more injections made every 24 h, fully prevent the death of operated animals and reduces the development of habitation deficit (open-field test) and decrease in exploratory activity (novel object examination) two weeks after surgery, as well as fully restores the viability of cerebral cortex cells and decreases the hyperexpression of HSP70 in cerebral cortex.

[A model study of the role of proteins CLV1, CLV2, CLV3, and WUS in regulation of the structure of the shoot apical meristem]

In order to elucidate the role of proteins CLV1, CLV2, CLV3, and WUS in the mechanism underlying the maintenance of compartmental structure (spatial arrangement of the zones of biosynthesis of marker proteins) of the shoot apical meristem, a model of such mechanism was developed. Computational experiments led to biologically plausible solutions only when synthesis of substance W in a space between the organizing center and meristem apex was limited by the mechanism based on interaction of CLV3 with membrane receptor CLV1/CKV2 and lower boundary of the zone of W synthesis was determined by isoline of the corresponding threshold level of substance Y concentration. The model of the "reaction-diffusion" type formalizing the role proteins CLV1, CLV2, CLV3, and WUS can describe the basis of the mechanism underlying regulation of the compartmental structure of the shoot apical meristem and positioning of the organizing center in a certain site of the cell ensemble of such meristem.

[Synthesis, structure, and biological properties of some 8alpha-analogues of steroid estrogens with fluorine in position 2]

A total synthesis of 8alpha analogues of steroid estrogens with fluorine in position 2 was achieved. Structural features of these compounds were studied by the example of 17beta-acetoxy-2-fluoro-3-methoxy-8alpha-estra-1,3,5(10)-triene. It was shown that the 8alpha analogues of 2-fluorosubstituted steroid estrogens have a low uterotropic activity and retain the osteoprotective and hypocholesterolemic activities.

[Experience with continuous epidural anesthesia used in the complex of combined anesthesia at gastropancreatoduodenal surgery]

The purpose of this study was to assess the experience with long-term epidural space administration of 1% lidocaine in combination with general anesthesia. Anesthesia based on the long-term epidural lidocaine administration in combination with general anesthesia versus total intravenous anesthesia based in ketamine and ataralgesia was analyzed. The anesthesia based on the long-term epidural lidocaine administration in combination with general anesthesia was shown to provide steady-state hemodynamic parameters and an adequate antinociceptive protection and to contribute to the early activation of patients.

The effects of substance P after central administration on the activity of the mesolimbic system of the rat brain as studied by microdialysis

In vivo microdialysis was used to study the effects of substance P on dopamine, dihydroxyphenylacetic acid, and homovanillic acid levels in the nucleus accumbens in rats. Each animal received sequential injections of physiological saline, 0.1 microg of substance P, and 1 microg of substance P into the lateral ventricle over three days. Dialysates showed increases in dopamine levels in response to neuropeptide, by 41% for the 0.1 microg dose and 71% for the 1 microg dose. The dynamics of these changes also depended on the concentration of the agent. Administration of 1 microg of substance P gave a peak dopamine level at 50 min; the neurotransmitter level remained significantly elevated 75 min after dosage with substance P. The dopamine level was increased only at 75 min when the 0.1 microg dose of neuropeptide was used. Changes in metabolite levels were also dose-dependent. After the 1 microg dose, the dihydroxyphenylacetic acid level increased by 28%, while the 0.1 microg dose produced no significant change in the level of this metabolite. The homovanillic acid level did not respond to administration of substance P at either dose. These data support the suggestion that the influence of substance P on the internal compensation system is to a significant extent mediated by dopaminergic mechanisms and provides a possible explanation for the effects of the neuropeptide seen in a conditioned place preference reflex.

Mechanisms of the influences of the central administration of substance P on ethanol consumption in chronically alcoholic rats

The effects of central administration of substance P (SP) on alcohol consumption and dopamine metabolism in the projections of the mesocorticolimbic and nigrostriatal systems of the brain were studied in chronically alcoholic rats. Rats received 15% ethanol solution for 6 months without choice. Intraventricular administration of SP (1 microg/rat) decreased consumption of 10% ethanol solution by 41% compared with controls in an alcohol free choice test lasting one day. After chronic alcoholism, there was a decrease in the ratio of dihydroxyphenylacetic acid (DOPA) and homovanillic acid (HVA) to dopamine in the nucleus accumbens and striatum in rats subjected to alcoholism, as compared with intact controls. Chronically alcoholic rats treated with SP showed increases in DOPA, HVA, and the DOPA:dopamine and HVA:dopamine ratios in the nucleus accumbens as compared with animals given physiological saline, by 17%, 23%, 9% and 19% respectively. The only increases in the striatum were in the absolute levels of DOPA and HVA, by 28% and 29%, while the ratios of these metabolites to dopamine remained unchanged. Thus, central administration of SP decreased the voluntary consumption of ethanol in the ethanol free choice test and enhanced dopamine metabolism in structures of the mesolimbic and nigrostriatal systems in chronically alcoholic rats.

[Effect of centrally administrated substance P on the brain mesolimbic system activity in rats as measured by microdialysis]

Action of substance P on the contents of dopamine, dihydroxyphenylacetic acid and homovanillic acid in the nucleus accumbens of rats was investigated with microdialysis procedure. During 3 days, each animal daily received i.v. the saline (the 1st day), 0.1 mcg of substance P (the 2nd day), 1 mcg of substance P (the 3rd day). Elevation of accumbal dopamine was observed amounting up to 41% and 71% for 0.1 mcg and 1 mcg of substance P, resp. Rates and duration of these changes also depended on neuropeptide concentration. 1 mcg of substance P produced the dopamine elevation with a peak by the 50th min. Moreover, in 75 min. after infusion of the neuropeptide, the levels of dopamine still remained increased. Response of metabolites also proved to be dose-related. With 1 mcg of substance P, the contents of dihydroxyphenylacetic acid increased by 28%, while with 0.1 mcg of substance P, this parameter did not change. Contents of homovanillie acid was unaffected by central substance P at the above doses. The data obtained corroborate the assumption of influence of the substance P on the reward system arising from its dopaminergic properties and provide a possible explanation of the neuropeptide effects observed in the conditioned place preference paradigm.

[The influence of substance P central administration on ethanol intake in rats chronically exposed to alcohol]

The influence of central substance P (SP) administration on alcohol intake and brain dopamine metabolism within mesocortico-limbic and nigrostiatal systems of rats exposed to ethanol, was studied. During 6 months, the rats consumed 15% ethanol solution instead of water. Central administration of SP (3 mcg/kg) decreased alcohol consumption by 41% in alcohol-preference animals. After long-term ethanol exposure ratios DOPAC/DA and HVA/DA were reduced in striatum and accumbens. SP in dose 3 mcg/kg increased content of DOPAC by 17% and HVA by 23% as well as DOPAC/DA by 9%, HVA/DA by 19% in accumbens. Whereas in striatum only increased DOPAC (28%) and HVA (29%) were observed as compared with saline-treated rats.

[A comparison of the hormonal and etholotropic activity of luliberin and its analogs]

The paper is devoted to comparative analysis of the activity of peptides (LH-RH analogs) with relation to their action on ovulation as well as on the learning capabilities and their effect on immobilization stress in rats. The acceleration of learning processes and elimination of immobilization stress were shown to be caused by LH-RH and its analogs, regulating actively ovulation under experimental conditions. The comparative evaluation of their action has shown that LH-RH analogs-antagonists produce a more marked effect on the process of learning and elimination of stress consequences than its analogs-agonists.

[Effect of a cyclic luliberin analog on ovulation]

A study was made of the cyclic LH-RH analog and its linear precursor on infantile and mature female rats. The compounds showed various biological properties which manifested themselves in their effects on ovulation. The linear analog proved to be an antagonist and the cyclic analog the LH-RH agonist. A hypothesis to the effect that the LH-RH biologically active conformation has a quasicyclic structure, has been confirmed.