Acute Toxicity Assessment of Orally Administered Microplastic Particles in Adult Male Wistar Rats.

While the effects of chronic exposure to microplastic particles (MPs) are extensively studied, the outcomes of a single treatment have received relatively less attention. To investigate MPs' potential acute toxicity, including their impact on general health status (victual consumption, sensorimotor deficits, and clinical toxicity signs) and serum biochemical parameters (markers of organ/tissue function and oxidative stress indicators), we administered thoroughly characterized MPs (1.4, 35, or 125 mg/kg), generated from polyethylene terephthalate (PET) bottles, to adult male Wistar rats via oral gavage. The MPs' short-term effects were assessed with well-established tests and methods. The results point to the absence of sensorimotor deficits and clinical toxicity signs, while levels of markers of liver, heart, and kidney function were altered in all MP groups. Decreased victual consumption and increased levels of oxidative stress indicators were evident following treatment with the two higher MP doses. Presented data indicate that examined MPs are able to initiate the development of local changes in tissues and organs within a short time frame, potentially leading to their damage and dysfunction. This study may increase the awareness of the detrimental effects of plastic contamination, as even a single exposure to MPs may provoke adverse health outcomes.

Comparable Toxicity of Surface-Modified TiO2 Nanoparticles: An In Vivo Experimental Study on Reproductive Toxicity in Rats.

Nanoparticles (NPs), a distinct class of particles ranging in size from 1 to 100 nm, are one of the most promising technologies of the 21st century, and titanium dioxide NPs (TiO2 NPs) are among the most widely produced and used NPs globally. The increased application of TiO2 NPs raises concerns regarding their global safety and risks of exposure. Many animal studies have reported the accumulation of TiO2 NPs in female reproductive organs; however, evidence of the resultant toxicity remains ambiguous. Since the surface area and chemical modifications of NPs can significantly change their cytotoxicity, we aimed to compare the toxic effects of pristine TiO2 powder with surface-modified TiO2 powders with salicylic acid (TiO2/SA) and 5-aminosalicylic acid (TiO2/5-ASA) on the ovaries, oviducts, and uterus on the 14th day following acute oral treatment. The results, based on alterations in food and water intake, body mass, organ-to-body mass ratio, hormonal status, histological features of tissues of interest, and antioxidant parameters, suggest that the modification with 5-ASA can mitigate some of the observed toxic effects of TiO2 powder and encourage future investigations to create NPs that can potentially reduce the harmful effects of TiO2 NPs while preserving their positive impacts.

Serum High-Mobility Group Box 1 and Heme Oxygenase-1 as Biomarkers in COVID-19 Patients at Hospital Admission.

The careful monitoring of patients with mild/moderate COVID-19 is of particular importance because of the rapid progression of complications associated with COVID-19. For prognostic reasons and for the economic management of health care resources, additional biomarkers need to be identified, and their monitoring can conceivably be performed in the early stages of the disease. In this retrospective cross-sectional study, we found that serum concentrations of high-mobility group box 1 (HMGB1) and heme oxygenase-1 (HO-1), at the time of hospital admission, could be useful biomarkers for COVID-19 management. The study included 160 randomly selected recovered patients with mild to moderate COVID-19 on admission. Compared with healthy controls, serum HMGB1 and HO-1 levels increased by 487.6 pg/mL versus 43.1 pg/mL and 1497.7 pg/mL versus 756.1 pg/mL, respectively. Serum HO-1 correlated significantly with serum HMGB1, oxidative stress parameters (malondialdehyde (MDA), the phosphatidylcholine/lysophosphatidylcholine ratio (PC/LPC), the ratio of reduced and oxidative glutathione (GSH/GSSG)), and anti-inflammatory acute phase proteins (ferritin, haptoglobin). Increased heme catabolism/hemolysis were not detected. We hypothesize that the increase in HO-1 in the early phase of COVID-19 disease is likely to have a survival benefit by providing protection against oxidative stress and inflammation, whereas the level of HMGB1 increase reflects the activity of the innate immune system and represents levels within which the disease can be kept under control.

Chronic oral d-galactose intake provokes age-related changes in the rat prefrontal cortex.

D-galactose (d-gal) is broadly used in animal aging studies as its chronic administration mimics learning and memory impairments related to aging in humans. However, within the few studies that utilize chronic oral d-gal intake, none of them is focused on alteration in synaptic structure and function. We examined the effects of 6-weeks oral d-gal intake (200 mg/kg and 500 mg/kg, dissolved in tap water) on age-related changes, with emphasis on the prefrontal cortex (PFC) and hippocampus (HIP) of adult male Wistar rats. Memory assessment was followed by histological examination of the PFC and HIP (Nissl staining and Iba-1 immunostaining), while in crude synaptosomal fractions the state of oxidative stress and the expression of proteins involved in glutamatergic signaling was determined. Although applied dosages compromised memory, alterations such as impaired sensory-motor function and aberrant morphology were not detected. In the PFC, analysis of microglia revealed reduction of branching pattern following d-gal intake, in parallel with increased oxidative damage of proteins, lipids and disturbed pro-oxidant antioxidant balance. These changes in the PFC were further accompanied with decreased levels of vesicular glutamate transporter 1, syntaxin-1 and NMDA receptor 2B subunit in both treated groups. Simultaneously, the increased hippocampal oxidative damage of lipids was detected. Results indicate successful provocation of age-related changes following oral d-gal intake, and suggest greater sensitivity of the PFC to d-gal treatment than HIP.

Artificial intelligence approaches to the biochemistry of oxidative stress: Current state of the art.

Artificial intelligence (AI) and machine learning models are today frequently used for classification and prediction of various biochemical processes and phenomena. In recent years, numerous research efforts have been focused on developing such models for assessment, categorization, and prediction of oxidative stress. Supervised machine learning can successfully automate the process of evaluation and quantification of oxidative damage in biological samples, as well as extract useful data from the abundance of experimental results. In this concise review, we cover the possible applications of neural networks, decision trees and regression analysis as three common strategies in machine learning. We also review recent works on the various weaknesses and limitations of artificial intelligence in biochemistry and related scientific areas. Finally, we discuss future innovative approaches on the ways how AI can contribute to the automation of oxidative stress measurement and diagnosis of diseases associated with oxidative damage.

The Effects of a Meldonium Pre-Treatment on the Course of the LPS-Induced Sepsis in Rats.

A dysregulated and overwhelming response to an infection accompanied by the exaggerated pro-inflammatory state and metabolism disturbance leads to the fatal outcome in sepsis. Previously we showed that meldonium, an anti-ischemic drug clinically used to treat myocardial and cerebral ischemia, strongly increases mortality in faecal-induced peritonitis (FIP) in rats. We postulated that the same mechanism that is responsible for the otherwise strong anti-inflammatory effects of meldonium could be the culprit of the increased mortality. In the present study, we applied the LPS-induced model of sepsis to explore the presence of any differences from and/or similarities to the FIP model. When it comes to energy production, despite some shared similarities, it is evident that LPS and FIP models of sepsis differ greatly. A different profile of sympathoadrenal activation may account for this observation, as it was lacking in the FIP model, whereas in the LPS model it was strong enough to overcome the effects of meldonium. Therefore, choosing the appropriate model of sepsis induction is of great importance, especially if energy homeostasis is the main focus of the study. Even when differences in the experimental design of the two models are acknowledged, the role of different patterns of energy production cannot be excluded. On that account, our results draw attention to the importance of uninterrupted energy production in sepsis but also call for much-needed revisions of the current recommendations for its treatment.

Effects of C60 Fullerene on Thioacetamide-Induced Rat Liver Toxicity and Gut Microbiome Changes.

Thioacetamide (TAA) is widely used to study liver toxicity accompanied by oxidative stress, inflammation, cell necrosis, fibrosis, cholestasis, and hepatocellular carcinoma. As an efficient free radical's scavenger, C60 fullerene is considered a potential liver-protective agent in chemically-induced liver injury. In the present work, we examined the hepatoprotective effects of two C60 doses dissolved in virgin olive oil against TAA-induced hepatotoxicity in rats. We showed that TAA-induced increase in liver oxidative stress, judged by the changes in the activities of SOD, CAT, GPx, GR, GST, the content of GSH and 4-HNE, and expression of HO-1, MnSOD, and CuZnSOD, was more effectively ameliorated with a lower C60 dose. Improvement in liver antioxidative status caused by C60 was accompanied by a decrease in liver HMGB1 expression and an increase in nuclear Nrf2/NF-κB p65 ratio, suggesting a reduction in inflammation, necrosis and fibrosis. These results were in accordance with liver histology analysis, liver comet assay, and changes in serum levels of ALT, AST, and AP. The changes observed in gut microbiome support detrimental effects of TAA and hepatoprotective effects of low C60 dose. Less protective effects of a higher C60 dose could be a consequence of its enhanced aggregation and related pro-oxidant role.

Immunohistochemical expression of cyclin-dependent kinase inhibitors p16 and p57 in rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is a highly malignant cancer and is the most common soft tissue sarcoma in children and adolescents, but it is rare in adults (<1% of all adult malignancies). Altered expression and molecular abnormalities of cell-cycle-regulatory proteins are one of the most prominent features in RMS. Therefore, we evaluated the expression of cyclin-dependent kinase inhibitors p57 and p16, as well as p16 methylation status, along with clinicopathological characteristics and overall survival (OS) in RMS patients. This analysis was conducted on 23 pediatric and 44 adult patients. There was a male predominance in both groups and extremities were the most frequent tumor site. In adults, alveolar and pleomorphic types were almost equally represented. The majority of pediatric tumors were low grade, whereas, in adults, only one patient had a low-grade tumor. Seven pediatric (30.43%) and eight adult (18.18%) patients had a low p16 expression. The analysis of methylation status of the p16 promoter showed the presence of methylated allele only in one sample with pleomorphic histology. Six (26.1%) pediatric and 15 (34.1%) adult patients had low p57 expression, while in 17 (73.9%) pediatric and 29 (65.9%) adult patients it was assessed as high. Ninetyone percent of the pediatric patients and 32.6% of adults were alive at the end of the observational period. In adults, significant associations were found between OS and age (P = 0.020), gender (P = 0.027), tumor size (P < 0.001), lymph node status (P < 0.001), presence of metastases (P = 0.015), and p57 expression (P = 0.039). Stratification by histological type showed the correlation of low p57 expression (P = 0.030) and worse OS of patients with alveolar RMS. Univariate analysis identified age > 50 yrs. (HR 2.447), tumors > 5 cm (HR 21.31), involvement of regional lymph nodes (HR 3.96), the presence of metastases (HR 2.53), and low p57 expression (HR 2.11) as predictors of lower OS. Tumor size, regional lymph nodes involvement, and metastases were the independent predictors after multivariate analysis, while p57 did not predict OS in an independent way. In summary, although p57 was not confirmed to be an independent predictor of OS, our results indicate that its low expression may be the marker of aggressive phenotype and poor prognosis in adult RMS patients. Also, our findings suggest that epigenetic inactivation of p16 is not important in the pathogenesis of rhabdomyosarcoma.

Effects of fullerene C60 supplementation on gut microbiota and glucose and lipid homeostasis in rats.

The effects of twelve weeks of supplementation with fullerene C60 olive/coconut oil solution on a broad spectrum of parameters in rats were examined. The tissue bioaccumulation of C60 was shown to be tissue-specific, with the liver, heart, and adrenal glands being the organs of the greatest, and the kidney, brain, and spleen being the organs of the smallest accumulation. C60 did not change aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase serum activities level, nor the damage of liver cells DNA. There were no effects of fullerene on prooxidant-antioxidant balance in the liver, kidney, spleen, heart, and brain, nor any visible harmful effects on the liver, heart, aorta, spleen, kidney, and small intestine histology. Fullerene changed the gut microbiota structure towards the bacteria that ameliorate lipid homeostasis, causing a serum triglycerides concentration decrease. However, C60 significantly increased the insulin resistance, serum ascorbate oxidation, and brain malondialdehyde and advanced oxidation protein products level. The deteriorative effects of C60 on the brain and serum could be attributed to the specific physicochemical composition of these tissues, potentiating the C60 aggregation or biotransformation as the key element of its pro-oxidative action.

Yellow gentian root extract provokes concentration- and time-dependent response in peripheral blood mononuclear cells.

Yellow gentian (Gentiana lutea L.), a medicinal plant widely used in traditional medicine, displays multiple biological effects, ranging from beneficial to toxic. Since many promising applications have been reported so far, our aim was to evaluate its potential concentration- and time- dependent cytotoxic and genotoxic effects in vitro. To that end we exposed human peripheral blood mononuclear cells to 0.5, 1, and 2 mg/mL of yellow gentian root extract (YGRE) to determine its effects on oxidative stress parameters [pro/antioxidant balance (PAB) and lipid peroxidation], DNA damage (alkaline comet assay and chromosome aberrations), and cell viability (trypan blue exclusion test). Cell viability decreased with increasing concentrations and treatment duration. Only the lowest YGRE concentration (0.5 mg/mL) increased oxidative stress but produced minor DNA damage and cytotoxicity. At higher concentrations, redox parameters returned to near control values. The percentage of chromosome aberrations and percentage of DNA in the comet tail increased with increased YGRE concentration after 48 h and declined after 72 h of treatment. This points to the activation of DNA repair mechanism (homologous recombination), evidenced by the formation of chromosomal radial figures after 72 h of treatment with the highest YGRE concentration of 2 mg/mL. Our results suggest that YGRE, despite induction of cytotoxic and genotoxic effects, activates cell repair mechanisms that counter oxidative and DNA lesions and induce cell death in highly damaged cells. Therefore, observed protective effects of yellow gentian after longer exposure could be a result of activated repair and removal of cells with irreparable damage.

Increased plasma phosphatidylcholine/lysophosphatidylcholine ratios in patients with Parkinson's disease.

RATIONALE: Changes in lipid composition might be associated with the onset and progression of various neurodegenerative diseases. Herein, we investigated the changes in the plasma phosphatidylcholine (PC)/lysophosphatidylcholine (LPC) ratios in patients with Parkinson's disease (PD) in comparison with healthy subjects and their correlation with clinico-pathological features. METHODS: The study included 10 controls and 25 patients with PD. All patients were assigned to groups based on clinico-pathological characteristics (gender, age at examination, duration of disease and Hoehn and Yahr (H&Y) stage). The analysis of the PC/LPC intensity ratios in plasma lipid extracts was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: PD patients exhibited an increased PC/LPC intensity ratio in comparison with the control group of healthy subjects. Furthermore, the investigated ratio was shown to be correlated with clinico-pathological parameters, in particular with H&Y stage and disease duration. The PC/LPC intensity ratio in plasma samples of PD patients was found to be elevated in all examined H&Y stages and throughout the disease duration. CONCLUSIONS: To our knowledge, this is the first study examining the PC/LPC ratios in plasma of patients with PD and illustrating their correlation with clinico-pathological features. Although the presented results may be considered as preliminary due to the limited number of participants, the observed alterations of PC/LPC ratios in plasma might be a first step in the characterization of plasma lipid changes in PD patients and an indicator of lipid reconfiguration.

Progesterone Protects Prefrontal Cortex in Rat Model of Permanent Bilateral Common Carotid Occlusion via Progesterone Receptors and Akt/Erk/eNOS.

Sustained activation of pro-apoptotic signaling due to a sudden and prolonged disturbance of cerebral blood circulation governs the neurodegenerative processes in prefrontal cortex (PFC) of rats whose common carotid arteries are permanently occluded. The adequate neuroprotective therapy should minimize the activation of toxicity pathways and increase the activity of endogenous protective mechanisms. Several neuroprotectants have been proposed, including progesterone (P4). However, the underlying mechanism of its action in PFC following permanent bilateral occlusion of common carotid arteries is not completely investigated. We, thus herein, tested the impact of post-ischemic P4 treatment (1.7 mg/kg for seven consecutive days) on previously reported aberrant neuronal morphology and amount of DNA fragmentation, as well as the expression of progesterone receptors along with the key elements of Akt/Erk/eNOS signal transduction pathway (Bax, Bcl-2, cytochrome C, caspase 3, PARP, and the level of nitric oxide). The obtained results indicate that potential amelioration of histological changes in PFC might be associated with the absence of activation of Bax/caspase 3 signaling cascade and the decline of DNA fragmentation. The study also provides the evidence that P4 treatment in repeated regiment of administration might be effective in neuronal protection against ischemic insult due to re-establishment of the compromised action of Akt/Erk/eNOS-mediated signaling pathway and the upregulation of progesterone receptors.

Estrogen receptors modulate ectonucleotidases activity in hippocampal synaptosomes of male rats.

Extracellular adenine nucleotides and nucleosides, such as adenosine-5'-triphosphate (ATP) and adenosine, are among least investigated signaling factors that participate in 17ß-estradiol (E2)-mediated synaptic rearrangements in rodent hippocampus. Their levels in the extrasynaptic space are tightly controlled by ecto-nucleoside triphosphate diphosphohydrolases1-3 (NTPDase1-3)/ecto-5'-nucleotidase (eN) enzyme chain. Therefore, the aim of the present study was to get closer insight in the E2-induced decrease in NTPDase and eN activity in the hippocampal synaptic compartment of male rats and to identify estradiol receptors (ERs i.e. ERα, ERß or GPER1) responsible for the observed effects of E2. In this study we show indiscriminate participation of estradiol receptor α (ERα), -ß (ERß) and G- protein coupled estrogen receptor 1 (GPER1) in the mediation of E2 actions in hippocampal synaptosomes of male rats. Synaptic NTPDase1-3 activities are modulated only through activation of ERß, while activation of ERα, -ß and/or non-classical GPER1 decreases synaptic eN activity. Since both ATP and adenosine function as neuromodulators in the hippocampal networks, influencing its function, profound knowledge of mechanisms by which ectonucleotidases are regulated/modulated is of great importance.

Molecular Alterations and Effects of Acute Dehydroepiandrosterone Treatment Following Brief Bilateral Common Carotid Artery Occlusion: Relevance to Transient Ischemic Attack.

Transient ischemic attack (TIA) represents brief neurological dysfunction of vascular origin without detectable infarction. Despite major clinical relevance characterization of post-TIA molecular changes using appropriate experimental model is lacking and no therapeutic agent has been established yet. Neurosteroid dehydroepiandrosterone (DHEA) arose as one of the candidates for cerebral ischemia treatment but its effects on TIA-like condition remain unknown. Seeking an animal model applicable for investigation of molecular alterations in mild ischemic conditions such as TIA, 15-min bilateral common carotid artery occlusion with 24-h reperfusion was performed to induce ischemia/ reperfusion (I/R) injury in adult male Wistar rats. Additionally, effects of 4-h post-operative DHEA treatment (20 mg/kg) were investigated in physiological and I/R conditions in hippocampus (HIP) and prefrontal cortex (PFC). The study revealed absence of sensorimotor deficits, cerebral infarcts and neurodegeneration along with preserved HIP and PFC overall neuronal morphology and unaltered malondialdehyde and reduced glutathione level following I/R and/or DHEA treatment. I/R induced nitric oxide burst in HIP and PFC was accompanied with increased neuronal nitric oxide synthase protein level exclusively in HIP. DHEA had no effects in physiological conditions, while increase of Bax/Bcl2 ratio and dissipation of mitochondrial membrane potential in treated I/R group suggested DHEA-mediated exacerbation of post-ischemic changes that might lead to pro-apoptotic events in HIP. Interestingly, DHEA restored I/R-induced NO to the control level in PFC. Obtained results indicated that I/R may serve as an appropriate model for investigation of molecular changes and treatment outcome following mild ischemic conditions such as TIA.

Role of Ectonucleotidases in Synapse Formation During Brain Development: Physiological and Pathological Implications.

BACKGROUND: Extracellular adenine nucleotides and nucleosides, such as ATP and adenosine, are among the most recently identified and least investigated diffusible signaling factors that contribute to the structural and functional remodeling of the brain, both during embryonic and postnatal development. Their levels in the extracellular milieu are tightly controlled by various ectonucleotidases: ecto-nucleotide pyrophosphatase/phosphodiesterases (E-NPP), alkaline phosphatases (AP), ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) and ecto-5'- nucleotidase (eN). METHODS: Studies related to the expression patterns of ectonucleotidases and their known features during brain development are reviewed, highlighting involvement of these enzymes in synapse formation and maturation in physiological as well as in pathological states. RESULTS: During brain development and in adulthood all ectonucleotidases have diverse expression pattern, cell specific localization and function. NPPs are expressed at early embryonic days, but the expression of NPP3 is reduced and restricted to ependymal area in adult brain. NTPDase2 is dominant ectonucleotidase existing in the progenitor cells as well as main astrocytic NTPDase in the adult brain, while NTPDase3 is fully expressed after third postnatal week, almost exclusively on varicose fibers. Specific brain AP is functionally associated with synapse formation and this enzyme is sufficient for adenosine production during neurite growth and peak of synaptogenesis. eN is transiently associated with synapses during synaptogenesis, however in adult brain it is more glial than neuronal enzyme. CONCLUSION: Control of extracellular adenine nucleotide levels by ectonucleotidases are important for understanding the role of purinergic signaling in developing tissues and potential targets in developmental disorders such as autism.

Spatial Distribution and Expression of Ectonucleotidases in Rat Hippocampus After Removal of Ovaries and Estradiol Replacement.

Purinergic signaling is the main synaptic and non-synaptic signaling system in brain. ATP acts as a fast excitatory transmitter, while adenosine sets a global inhibitory tone within hippocampal neuronal networks. ATP and adenosine are interconnected by ectonucleotidase enzymes, which convert ATP to adenosine. Existing data point to the converging roles of ovarian steroids and purinergic signaling in synapse formation and refinement and synapse activity in the hippocampus. Therefore, in the present study, we have used enzyme histochemistry and expression analysis to obtain data on spatial distribution and expression of ecto-enzymes NTPDase1, NTPDase2, and ecto-5'-nucleotidase (eN) after removal of ovaries (OVX) and estradiol replacement (E2) in female rat hippocampus. The results show that target ectonucleotidases are predominantly localized in synapse-rich hippocampal layers. The most represented NTPDase in the hippocampal tissue is NTPDase2, being at the same time the mostly affected ectonucleotidase by OVX and E2. Specifically, OVX decreases the expression of NTPDase2 and eN, whereas E2 restores their expression to control level. Impact of OVX and E2 on ectonucleotidase expression was also examined in purified synaptosome (SYN) and gliosome (GLIO) fractions. Data reveal that SYN expresses NTPDase1 and NTPDase2, both of which are reduced following OVX and restored with E2. GLIO exhibits NTPDase2-mediated ATP hydrolysis, which falls in OVX, and recovers by E2. These changes in the activity occur without parallel changes in NTPDase2-protein abundance. The same holds for eN. The lack of correlation between NTPDase2 and eN activities and their respective protein abundances suggest a non-genomic mode of E2 action, which is studied further in primary astrocyte culture. Since ovarian steroids shape hippocampal synaptic networks and regulate ectonucleotidase activities, it is possible that cognitive deficits seen after ovary removal may arise from the loss of E2 modulatory actions on ectonucleotidase expression in the hippocampus.

Regional-specific effects of cerebral ischemia/reperfusion and dehydroepiandrosterone on synaptic NMDAR/PSD-95 complex in male Wistar rats.

Excessive glutamate efflux and N-methyl-D-aspartate receptor (NMDAR) over-activation represent well-known hallmarks of cerebral ischemia/reperfusion (I/R) injury, still, expression of proteins involved in this aspect of I/R pathophysiology show inconsistent data. Neurosteroid dehydroepiandrosterone (DHEA) has been proposed as potent NMDAR modulator, but its influence on I/R-induced changes up to date remains questionable. Therefore, I/R-governed alteration of vesicular glutamate transporter 1 (vGluT1), synaptic NMDAR subunit composition, postsynaptic density protein 95 (PSD-95) and neuronal morphology alone or following DHEA treatment were examined. For that purpose, adult male Wistar rats were treated with a single dose of vehicle or DHEA (20 mg/kg i.p.) 4 h following sham operation or 15 min bilateral common carotid artery occlusion. Western blot was used for analyses of synaptic protein expressions in hippocampus and prefrontal cortex, while neuronal morphology was assessed using Nissl staining. Regional-specific postischemic changes were detected on protein level i.e. signs of neuronal damage in CA1 area was accompanied with hippocampal vGluT1, NR1, NR2B enhancement and PSD-95 decrement, while histological changes observed in layer III were associated with decreased NR1 subunit in prefrontal cortex. Under physiological conditions DHEA had no effect on protein and histological appearance, while in ischemic milieu it restored hippocampal PSD-95 and NR1 in prefrontal cortex to the control level. Along with intact neurons, ones characterized by morphology observed in I/R group were also present. Future studies involving NMDAR-related intracellular signaling and immunohistochemical analysis will reveal precise effects of I/R and DHEA treatment in selected brain regions.

Prooxidant-antioxidant balance, advanced oxidation protein products and lipid peroxidation in Serbian patients with Parkinson's disease.

BACKGROUND: Biomarkers of oxidative stress are relevant in the evaluation of the disease status and prooxidant-antioxidant balance, advanced oxidation protein products and lipid peroxidation products (malondialdehyde and 4-hydroxynonenal) are being extensively evaluated regarding their relationship with clinical presentation and disease severity. AIM OF THE STUDY: The aim of this study was to evaluate the levels of the above-mentioned parameters in plasma of 39 men and 17 women with Parkinson's disease, originated from the Republic of Serbia and their relation to clinicopathological characteristics (gender, age at examination, duration of the disease, and Hoehn and Yahr score) and oxidative status. RESULTS: The incidence of disease was 2:1 towards males. The investigated oxidative parameters were gender and Hoehn and Yahr related. Significant association of higher Hoehn and Yahr scores was observed for malondialdehyde (p = 0.01) and prooxidant-antioxidant balance (p = 0.02). Relation between oxidant-antioxidant status was further supported by observed positive correlation between 4-hydroxynonenal (p = 0.04) and prooxidant-antioxidant balance (p = 0.03). Finally, the multivariate analysis indicated that prooxidant-antioxidant balance and malondialdehyde were partially determined by gender (10.6% and 7.6%) and Hoehn and Yahr scores (13.6% and 18.8%), while Hoehn and Yahr scores contributed to the variance of advanced oxidation protein products with 13.2%. CONCLUSION: Our results indicate the higher level of oxidative stress (oxidant-antioxidant imbalance) and possible relation of several markers with gender and disease stage in patients with Parkinson's disease. The analyzed markers could be used to specify the severity of oxidative stress; however, their potential value should be analyzed in further studies.

17ß-Estradiol-Induced Synaptic Rearrangements Are Accompanied by Altered Ectonucleotidase Activities in Male Rat Hippocampal Synaptosomes.

17ß-Estradiol (E2) rapidly, by binding to membrane estrogen receptors, activates cell signaling cascades which induce formation of new dendritic spines in the hippocampus of males as in females, but the interaction with other metabolic processes, such as extracellular adenine nucleotides metabolism, are currently unknown. Extracellular adenine nucleotides play significant roles, controlling excitatory glutamatergic synapses and development of neural circuits and synaptic plasticity. Their precise regulation in the synaptic cleft is tightly controlled by ecto-nucleoside triphosphate diphosphohydrolase (NTPDase)/ecto-5'-nucleotidase (eN) enzyme chain. Therefore, we sought to clarify whether a single systemic injection of E2 in male rats is accompanied by changes in the expression of the pre- and postsynaptic proteins and downstream kinases linked to E2-induced synaptic rearrangement as well as alterations in NTPDase/eN pathway in the hippocampal synaptosomes. Obtained data showed activation of mammalian target of rapamycin and upregulation of key synaptic proteins necessary for spine formation, 24 h after systemic E2 administration. In E2-mediated conditions, we found downregulation of NTPDase1 and NTPDase2 and attenuation of adenine nucleotide hydrolysis by NTPDase/eN enzyme chain, without changes in NTPDase3 properties and augmentation of synaptic tissue-nonspecific alkaline phosphatase (TNAP) activity. Despite reduced NTPDase activities, increased TNAP activity probably prevents toxic accumulation of ATP in the extracellular milieu and also hydrolyzes accumulated ADP due to unchanged NTPDase3 activity. Thus, our initial evaluation supports idea of specific roles of different ectonucleotidases and their coordinated actions in E2-mediated spine remodeling and maintenance.