Biological Activity of 6,7-Dehydroxyroyleanone and Derivatives Obtained from Plectranthus aliciae (Codd) A.J.Paton

The Plectranthus genus (Lamiaceae) is known to be rich in abietane diterpenes. The bioactive 6,7-dehydroxyroyleanone (DHR, 1) was previously isolated from Plectranthus madagascariensis var. madagascariensis and var. aliciae. This study aimed to explore the occurrence of DHR, 1, in P. aliciae and the potential bioactivities of new semisynthetic derivatives from DHR, 1. Several extraction methods were evaluated, and the hydrodistillation, using a Clevenger apparatus, afforded the highest yield (77.8 mg/g of 1 in the essential oil). Three new acyl derivatives (2-4) were successfully prepared from 1 (yields of 86-95%). Compounds 1-4 showed antioxidant activity, antibacterial effects, potent cytotoxic activity against several cell lines, and enhanced anti-inflammatory activity that surpassed dexamethasone (positive control). These findings encourage further exploration of derivatives 2-4 for potential mechanisms of antitumoral, antioxidant, and anti-inflammatory capabilities, studying both safety and efficacy.

The Thiol Group Reactivity and the Antioxidant Property of Human Serum Albumin Are Controlled by the Joint Action of Fatty Acids and Glucose Binding

The binding of ubiquitous serum ligands (free fatty acids) to human serum albumin (HSA) or its glycation can affect thiol group reactivity, thus influencing its antioxidant activity. The effects of stearic acid (SA) and glucose binding on HSA structural changes and thiol group content and reactivity were monitored by fluoroscopy and the Ellman method during a 14-day incubation in molar ratios to HSA that mimic pathophysiological conditions. Upon incubation with 5 mM glucose, HSA glycation was the same as HSA without it, in three different HSA:SA molar ratios (HSA:SA-1:1-2-4). The protective effect of SA on the antioxidant property of HSA under different glucose regimes (5-10-20 mM) was significantly affected by molar ratios of HSA:SA. Thiol reactivity was fully restored with 5-20 mM glucose at a 1:1 HSA:SA ratio, while the highest thiol content recovery was in pathological glucose regimes at a 1:1 HSA:SA ratio. The SA affinity for HSA increased significantly (1.5- and 1.3-fold, p < 0.01) with 5 and 10 mM glucose compared to the control. These results deepen the knowledge about the possible regulation of the antioxidant role of HSA in diabetes and other pathophysiological conditions and enable the design of future HSA-drug studies which, in turn, is important for clinicians when designing information-based treatments.

Quinoline-based thiazolyl-hydrazones target cancer cells through autophagy inhibition

Heterocyclic pharmacophores such as thiazole and quinoline rings have a significant role in medicinal chemistry. They are considered privileged structures since they constitute several Food and Drug Administration (FDA)-approved drugs for cancer treatment. Herein, we report the synthesis, in silico evaluation of the ADMET profiles, and in vitro investigation of the anticancer activity of a series of novel thiazolyl-hydrazones based on the 8-quinoline (1a-c), 2-quinoline (2a-c), and 8-hydroxy-2-quinolyl moiety (3a-c). The panel of several human cancer cell lines and the nontumorigenic human embryonic kidney cell line HEK-293 were used to evaluate the compound-mediated in vitro anticancer activities, leading to [2-(2-(quinolyl-8-ol-2-ylmethylene)hydrazinyl)]-4-(4-methoxyphenyl)-1,3-thiazole (3c) as the most promising compound. The study revealed that 3c blocks the cell-cycle progression of a human colon cancer cell line (HCT-116) in the S phase and induces DNA double-strand breaks. Also, our findings demonstrate that 3c accumulates in lysosomes, ultimately leading to the cell death of the hepatocellular carcinoma cell line (Hep-G2) and HCT-116 cells, by the mechanism of autophagy inhibition.

Influence of Long-Term Anti-Seizure Medications on Redox Parameters in Human Blood

BACKGROUND

Epilepsy is a chronic brain disease affecting millions of people worldwide, but little is known about the impact of anti-seizure medications on redox homeostasis.

METHODS

This study aimed to compare the effects of the long-term use of oral anti-seizure medications in monotherapy (lamotrigine, carbamazepine, and valproate) on antioxidant enzymes: superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, haemoglobin, and methaemoglobin content in erythrocytes, and concentrations of total proteins and thiols, nitrites, lipid peroxides and total glutathione in the plasma of epilepsy patients and drug-naïve patients.

RESULTS

The results showed that lamotrigine therapy led to lower superoxide dismutase activity (p < 0.005) and lower concentrations of total thiols (p < 0.01) and lipid peroxides (p < 0.01) compared to controls. On the other hand, therapy with carbamazepine increased nitrite levels (p < 0.01) but reduced superoxide dismutase activity (p < 0.005). In the valproate group, only a decrease in catalase activity was observed (p < 0.005). Canonical discriminant analysis showed that the composition of antioxidant enzymes in erythrocytes was different for both the lamotrigine and carbamazepine groups, while the controls were separated from all others.

CONCLUSIONS

Monotherapy with anti-seizure medications discretely alters redox homeostasis, followed by distinct relationships between antioxidant components.

Humoral and Cellular Immune Response after Three Doses of Sinopharm [Vero Cell]-Inactivated COVID-19 Vaccine in Combination with SARS-CoV-2 Infection Leads to Hybrid Immunity

BACKGROUND

Several vaccines against COVID-19 have been developed and licensed to enhance the immune response against SARS-CoV-2. Similarly, previous infection with SARS-CoV-2 has been shown to provide significant protection against severe infection and hospitalization.

METHODS

We investigated the effect of three doses of the Sinopharm vaccine and SARS-CoV-2 infection on the specific immune response in 103 volunteers, measuring neutralizing antibodies, anti-S1 IgG, anti-RBD IgM, anti-N IgM, anti-N IgG antibodies, and INF γ.

RESULTS

Our results showed that the presence of cardiovascular diseases increased the level of anti-N-IgG antibodies, while endocrinological diseases decreased the level of neutralizing antibodies and anti-N IgG antibodies, suggesting that these diseases alter the effect of vaccine-induced immunity. In addition, there was a significant decrease in anti-S1 IgG levels at 6 months and in anti-N IgG levels 18 months post-infection, while neutralizing antibodies and INF γ levels were constant at 3, 6, and 18 months post-infection.

CONCLUSIONS

Our results confirm the emergence of hybrid immunity, which is the strongest and most durable compared to natural immunity or vaccine-induced immunity. Significant positive correlations were found between humoral and cellular immunity markers: neutralizing antibodies, anti-S1 IgG and anti-N IgG antibodies, and INF γ, indicating a unique coordinated response specific to COVID-19.

Investigation of the Potential of Selected Food-Derived Antioxidants to Bind and Stabilise the Bioactive Blue Protein C-Phycocyanin from Cyanobacteria Spirulina

Blue C-phycocyanin (C-PC), the major Spirulina protein with innumerable health-promoting benefits, is an attractive colourant and food supplement. A crucial obstacle to its more extensive use is its relatively low stability. This study aimed to screen various food-derived ligands for their ability to bind and stabilise C-PC, utilising spectroscopic techniques and molecular docking. Among twelve examined ligands, the protein fluorescence quenching revealed that only quercetin, coenzyme Q10 and resveratrol had a moderate affinity to C-PC (Ka of 2.2 to 3.7 × 105 M-1). Docking revealed these three ligands bind more strongly to the C-PC hexamer than the trimer, with the binding sites located at the interface of two (αβ)3 trimers. UV/VIS absorption spectroscopy demonstrated the changes in the C-PC absorption spectra in a complex with quercetin and resveratrol compared to the spectra of free protein and ligands. Selected ligands did not affect the secondary structure content, but they induced changes in the tertiary protein structure in the CD study. A fluorescence-based thermal stability assay demonstrated quercetin and coenzyme Q10 increased the C-PC melting point by nearly 5 °C. Our study identified food-derived ligands that interact with C-PC and improve its thermal stability, indicating their potential as stabilising agents for C-PC in the food industry.

Phycocyanobilin is a new binding partner of human alpha-2-macroglobulin that protects the protein against oxidative stress

Under simulated physiological conditions, this study investigates the interaction between nutraceutical phycocyanobilin (PCB) and the universal anti-protease protein human alpha-2-macroglobulin (α2M). Extensive molecular docking analyses on multiple α2M conformations, spectroscopic techniques, and α2M activity assays were utilized to examine the complex formation. The results revealed that for every protein conformation, two high energy binding sites exist: the first, conformationally independent, at the interface region between two monomer chains and the second, conformationally dependent, in the pocket composed of amino acids from four distinct domains (TED, RBD, CUB, and MG2) of the single protein chain. Spectrofluorimetric measurements indicated a moderate affinity between α2M and PCB with a moderately high binding constant of 6.3 × 105 M-1 at 25 °C. The binding of PCB to α2M resulted in minor changes in the secondary structure content of α2M. Furthermore, PCB protected α2M from oxidation and preserved its anti-protease activity in the oxidative environment. These findings suggest that PCB binding could indirectly impact the body's response to oxidative stress by influencing α2M's role in controlling enzyme activity during the inflammatory process.Communicated by Ramaswamy H. Sarma.

Exploring and strengthening the potential of R-phycocyanin from Nori flakes as a food colourant

This study aimed to purify, characterise and stabilise the natural food colourant, R-phycocyanin (R-PC), from the red algae Porphyra spp. (Nori). We purified R-PC from dried Nori flakes with a high purity ratio (A₆₁₈/A₂₈₀ ≥ 3.4) in native form (α-helix content 53%). SAXS measurements revealed that R-PC is trimeric ((αβ)₃) in solution. The thermal denaturation of α-helix revealed one transition (T_m at 52 °C), while the pH stability study showed R-PC is stable in the pH range 4-8. The thermal treatment of R-PC at 60 °C has detrimental and irreversible effects on R-PC colour and antioxidant capacity (22 % of residual capacity). However, immobilisation of R-PC within calcium alginate beads completely preserves R-PC colour and mainly retains its antioxidant ability (78 % of residual capacity). Results give new insights into the stability of R-PC and preservation of its purple colour and bioactivity by encapsulation in calcium alginate beads.

Human Hemoglobin and Antipsychotics Clozapine, Ziprasidone and Sertindole: Friends or Foes?

Packed with hemoglobin, an essential protein for oxygen transport, human erythrocytes are a suitable model system for testing the pleiotropic effects of lipophilic drugs. Our study investigated the interaction between antipsychotic drugs clozapine, ziprasidone, sertindole, and human hemoglobin under simulated physiological conditions. Analysis of protein fluorescence quenching at different temperatures and data obtained from the van't Hoff diagram and molecular docking indicate that the interactions are static and that the tetrameric human hemoglobin has one binding site for all drugs in the central cavity near αβ interfaces and is dominantly mediated through hydrophobic forces. The association constants were lower-moderate strength (~10⁴ M^-1), the highest observed for clozapine (2.2 × 10⁴ M^-1 at 25 °C). The clozapine binding showed "friendly" effects: increased α-helical content, a higher melting point, and protein protection from free radical-mediated oxidation. On the other hand, bound ziprasidone and sertindole had a slightly pro-oxidative effect, increasing ferrihemoglobin content, a possible "foe". Since the interaction of proteins with drugs plays a vital role in their pharmacokinetic and pharmacodynamic properties, the physiological significance of the obtained findings is briefly discussed.

In vitro and in silico study of the biological activity of tetradentate Schiff base copper(II) complexes with ethylenediamine-bridge

The biological activity of six structurally similar tetradentate Schiff base copper(II) complexes, namely [Cu(ethylenediamine-bis-acetylacetonate)] (CuAA) and five derivatives where two methyl groups are replaced by phenyl, (CuPP), CF3 (CuTT) or by mixed groups CH3/CF3 (CuAT), Ph/CF3 (CuPT), and Ph/CH3 (CuAP) has been investigated. The set of antioxidant assays was performed, and the results were expressed as IC₅₀ and EC₅₀ values. The series of complexes showed interesting bioactivity and were investigated for the determination of antioxidant, antifungal, antimicrobial, and cytotoxic activity. A significant antioxidant behavior was exhibited by complex CuAA, greater than Trolox in the Oxygen Radical Absorbance Capacity (ORAC) assay. Antibacterial assay over Gram-positive and Gram-negative pathogenic bacterial strains and some fungal pathogens were studied. Antiproliferative activity of complexes in two human tumor cell lines, breast adenocarcinoma MCF-7, colon adenocarcinoma LS-174, and normal fibroblast cells-MRC-5, examined the effect on cell cycle progression. The significant cytotoxic potential, comparable to cisplatin cytotoxicity, was determined in human breast cancer cell line-MCF-7 with IC₅₀ values being 17.53-31.40 μM and human colon cancer cell line-LS-174 with IC₅₀ values being 15.22-23.92 μM. All tested compounds showed nearly twice more selectivity toward cancer cell lines than normal cells. The interactions of complexes with human serum albumin (HSA), the most prominent protein in plasma, were investigated using spectroscopic fluorescence techniques. The complexes bind to human serum albumin at multiple sites (n = 0.2-1.9), displaying a moderate binding constant K_a = 4.1-12.4 × 10⁴ M^-1. The molecular docking experiment effectively showed complex binding to HSA and DNA molecular fragments.

Food Antioxidants and Their Interaction with Human Proteins

Common to all biological systems and living organisms are molecular interactions, which may lead to specific physiological events. Most often, a cascade of events occurs, establishing an equilibrium between possibly competing and/or synergistic processes. Biochemical pathways that sustain life depend on multiple intrinsic and extrinsic factors contributing to aging and/or diseases. This article deals with food antioxidants and human proteins from the circulation, their interaction, their effect on the structure, properties, and function of antioxidant-bound proteins, and the possible impact of complex formation on antioxidants. An overview of studies examining interactions between individual antioxidant compounds and major blood proteins is presented with findings. Investigating antioxidant/protein interactions at the level of the human organism and determining antioxidant distribution between proteins and involvement in the particular physiological role is a very complex and challenging task. However, by knowing the role of a particular protein in certain pathology or aging, and the effect exerted by a particular antioxidant bound to it, it is possible to recommend specific food intake or resistance to it to improve the condition or slow down the process.

Metabolomic profiling relates tianeptine effectiveness with hippocampal GABA, myo-inositol, cholesterol, and fatty acid metabolism restoration in socially isolated rats

RATIONALE

Discovering biomarkers of major depressive disorder (MDD) can give a deeper understanding of this mood disorder and improve the ability to screen for, diagnose, and treat MDD.

OBJECTIVES

In this study, metabolomics was used in unraveling metabolite fluctuations of MDD and drug outcome by creating specific metabolomic fingerprints. We report metabolomic patterns of change of the hippocampus of adult male Wistar rats following chronic social isolation (CSIS) (6 weeks), an animal model of depression, and/or chronic tianeptine (Tian) treatment (10 mg kg^-1 per day) (lasting 3 weeks of 6-week CSIS), monitored by using comprehensive GC × GC-MS.

RESULTS

The comparative metabolomic analysis highlighted the role of gamma aminobutyric acid (GABA), iso-allocholate, and unsaturated fatty acid metabolism alterations following the CSIS, which was corroborated with moderate to strong negative Pearson's correlation of GABA, docosahexaenoic, 9-hexadecenoic acid, 5,8,11,14-eicosatetraynoic, and arachidonic acids with immobility behavior in the forced swim test. The antidepressant effect of Tian restored GABA levels, which was absent in Tian resilient rats. Tian decreased myo-inositol and increased TCA cycle intermediates, amino acids, and cholesterol and its metabolite. As key molecules of divergence between Tian effectiveness and resilience, metabolomics revealed myo-inositol, GABA, cholesterol, and its metabolite. A significant moderate positive correlation between myo-inositol and immobility was revealed. Tian probably acted by upregulating NMDAR's and α₂ adrenergic receptors (AR) or norepinephrine transporter in both control and stressed animals.

CONCLUSION

Metabolomics revealed several dysregulations underlying CSIS-induced depressive-like behavior and responsiveness to Tian, predominantly converging into NMDAR-mediated glutamate and myo-inositol signalization and GABA inhibitory pathways.

The influence of organizational culture and leadership on workplace bullying in organizations in Serbia

This paper presents the results of research into the influence and predictive effects of organizational culture and leadership (transformational, transactional and ethical leadership) on workplace bullying and mistreatment in organizations in Serbia. The moderating effect of company success on the observed relationships was also examined. The data were obtained through a survey of 536 respondents (employed by organizations in Serbia). Ethical and transformational leadership, as well as organizational culture with pronounced human orientation and in-group collectivism have all been shown to reduce workplace bullying. The strong power of ethical leadership in these processes is particularly emphasized. In contrast, transactional leadership, high power distance, and unrealistic insistence on achieving superior results increase the chances of workplace bullying. In doing so, high performance expectations have a greater effect on work-related bullying, and power distance on person-related bullying. The dimensions related to high performances and rewards have a complex, sometimes contradictory impact on workplace bullying. Organizational culture and leadership have a much stronger impact on workplace bullying in high success companies than in low success companies.

The onset of ulcerative colitis upon Helicobacter pylori eradication in a 72-year-old woman: report of a rare case with a 3-year follow-up

BACKGROUND

Epidemiological studies suggest an inverse association between H. pylori infection/exposure and inflammatory bowel disease prevalence/incidence, however, there are no reports of individual patients who developed a "non-transient" ulcerative colitis (UC) following H. pylori eradication.

CASE PRESENTATION

We report a case of a 72-year-old female with an elderly-onset UC developed upon H. pylori eradication and a 3-year follow-up of the progression to steroid-dependent colitis complicated with enteropathic arthritis and final containment of the disease with golimumab. In our patient, H. pylori eradication was associated with the development of pancolitis that evolved into clinically, endoscopically, and pathohistologically confirmed UC.

CONCLUSIONS

The case of our patient provides a unique clinical context for a growing body of literature suggesting molecular mechanisms involved in the interaction of genes, environment, and microbiota to be of critical importance in the etiopathogenesis of UC, and thus, provides a valuable set of complementary translational information for preclinical and epidemiological research on the topic.

Effects of several atypical antipsychotics closapine, sertindole or ziprasidone on hepatic antioxidant enzymes: Possible role in drug-induced liver dysfunction

Chronic use of atypical antipsychotics may produce hepatic damage. Atypical antipsychotics, including clozapine, sertindole, and ziprasidone, are extensively metabolized by the liver and this process generates toxic-free radical metabolic intermediates which may contribute to liver damage. The aim of this study was to investigate whether clozapine, sertindole, or ziprasidone affected hepatic antioxidant defense enzymes which consequently led to disturbed redox homeostasis. The expression and activity of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione-S-transferases (GST) were measured in rat livers at doses corresponding to human antipsychotic therapy. Clozapine increased activity of SOD types 1 and 2, GR and GST, but reduced CAT activity. Sertindole elevated activities of both SODs. In ziprasidone-treated rats only decreased CAT activity was found. All three antipsychotics produced mild-to-moderate hepatic histopathological changes categorized as regenerative alterations. No apparent signs of immune cell infiltration, microvesicular or macrovesicular fatty change, or hepatocytes in mitosis were observed. In conclusion, a 4-week long daily treatment with clozapine, sertindole, or ziprasidone altered hepatic antioxidant enzyme activities and induced histopathological changes in liver. The most severe alterations were noted in clozapine-treated rats. Data indicate that redox disturbances may contribute to liver dysfunction after long-term atypical antipsychotic drug treatment.

The managerial implications of the labor market and workplace shortage in Central Eastern Europe

In the recent years the labor market of the Central and Eastern European (CEE) countries has changed a lot. One of the main business challenges in the CEE region is the worker shortage. The possible reasons of this phenomenon are the emigration of the labor force from the countries of the former Eastern Bloc to the Western countries, the negative demographic tendencies in the region, the effects of economic crisis and the significant wage differences in the countries of European Union. This paper presents the first results of an international research conducted in six countries from the CEE region (Austria, Czech Republic, Hungary, Romania, Serbia and Slovakia) on the reasons and managerial implications of the current labor force shortage. The research questionnaire was filled out in 797 companies and institutions in the CEE region. In our paper we will show the size, ownership and the sectoral distribution of our sample, as well as the average turnover rate, the average time to fill a position in, the positions hard to fill in, the possible reasons of labor shortage and the successful organizational and governmental programs to deal with labor market shortage. The obtained results may be a useful input for the formulation of human resource management programs in the organizations facing with labor market shortage in Serbia and other CEE countries.

Characterizing plasma with emission tomography-Feasibility study on synthetic and experimental data

We present a feasibility study on different tomographic algorithms to overcome the issues of finite sets of projection data, limited viewing angles, and noisy data, which cause the tomographic reconstruction to be an ill-posed inversion problem. We investigated three approaches: single angle Abel inversion, two angle approach, and multiple angle 2D plasma tomography. These methods were tested on symmetric and asymmetric sample functions and on experimental results from a supersonic flowing argon microwave plasma sustained in a cylindrical quartz cavity. The analysis focused on the afterglow region of the microwave flow where a plasmoid-like formation was observed. We investigated the effects of the uniform random noise added to the simulated data by applying smoothing techniques. The quality of reconstructed images was assessed by using peak signal-to-noise ratio and universal quality image measures. The results showed that the Abel inversion approach could be employed only when the system is radially symmetric, while the systems with slight asymmetry could be reconstructed with the two angle approach. In the complete absence of symmetry, full 2D tomographic reconstruction should be applied. The data analysis showed that the best results were obtained by employing either the filtered back projection or the simultaneous algebraic reconstruction technique. The total variation minimization method proved to be the best denoising technique. Each approach was used to obtain the spatial distributions of argon excited states taken at three positions along the plasmoid-like structure. The results indicated that the plasma was asymmetric with argon populating the cavity surface.

The influence of organizational culture on the entrepreneurial intentions of employed persons: the Serbian case

The paper presents the results of the study of the influence of the dimensions of organizational culture on individual entrepreneurial orientation dimensions, the achievement dimension and the theory of planned behaviour dimensions. The respondents were employed persons. There were 540 respondents from 72 organizations. The moderating effect of the respondents’ gender on the observed relationships was also examined. From all the dimensions of organizational culture, power distance has the greatest impact on the entrepreneurial intentions of employed persons. Entrepreneurial intentions weaken when there is group collectivism in the organization and when there is an assertive environment in the organization.

National culture and the entrepreneurial intentions of students in Serbia

The paper presents the results of research into the influence of national culture on the enterprise potential, individual entrepreneurial orientation and entrepreneurial intentions of students in Serbia. The moderating and mediating effects of the possession of finance for opening one’s own company item on the observed relations were examined. National culture has a positive influence on entrepreneurship in cases where young people want to overcome the unfavourable circumstances in society and engage in entrepreneurship in order to become independent. In the case of a poor financial situation a stable environment is what can encourage the launch of one's own business.

Pd(II) complexes with N-heteroaromatic hydrazone ligands: Anticancer activity, in silico and experimental target identification

Anticancer activity of Pd complexes 1-5 with bidentate N-heteroaromatic hydrazone ligands was investigated on human acute monocytic leukemia (THP-1; cells in a suspension) and human mammary adenocarcinoma (MCF-7; two-dimensional layer and three-dimensional spheroid tumor model) cell lines. For the Pd(II) complexes with condensation products of ethyl hydrazainoacetate and quinoline-8-carboxaldehyde (complex 1) and 2-formylpyridine (complex 3), for which apoptosis was determined as a mechanism of anticancer activity, further investigation revealed that they arrest the cell cycle in G0/G1 phase, induce generation of reactive oxygen species and inhibit Topoisomerase I in vitro. In silico studies corroborate experimental findings that these complexes show topoisomerase inhibition activity in the micromolar range and indicate binding to a DNA's minor groove as another potential target. Based on the results obtained by circular dichroism and fluorescence spectroscopy measurements, the most active complexes are suitable to be delivered to a blood stream via human serum albumin.

Characterisation and the effects of bilirubin binding to human fibrinogen

Fibrinogen, a protein involved in blood coagulation, is very susceptible to oxidation. Oxidation alters its function and usually makes it more thrombogenic. Bilirubin, an end-product of the haem degradation in vertebrates, is known for its antioxidant properties. The present paper describes interaction between fibrinogen and bilirubin, and the influence of bilirubin on the formation of fibrin and protection against oxidation. The binding constant of 4.5 × 10⁴ M^-1 was determined for the fibrinogen/bilirubin complex at 37 °C. There is no change in secondary and tertiary structure of fibrinogen or its thermal stability upon bilirubin binding. The binding site of fibrinogen is not stereospecific for bilirubin and is able to accommodate both bilirubin conformers. A change in absorption maximum of bilirubin occurs upon its interaction with fibrinogen, suggesting an alteration in the conformation of bilirubin to the more cyclic one. Bilirubin exerts antioxidant effect on fibrinogen, preventing its carbonylation and aggregation. The presence of bilirubin induces the formation of fibrin with thicker fibres, as assessed by the coagulation assay. Fibrinogen and bilirubin interact at physiological concentrations, bilirubin may act as an antioxidant for fibrinogen and may modulate an important event in haemostasis, which altogether suggests possible physiological relevance of this interaction.

Effect of ZnO on Mechanical and Electrical Properties of Peroxide Cured EPDM

This paper presents reduction of ZnO in EPDM formulations and its influence on efficiency of cable isolation by measuring cure behavior, electrical and mechanical properties before and after ageing. These experiments were performed on EPDM formulations by changing three key variables in formulation (concentration of ZnO, type of peroxide and content of ethylene in EPDM). The rheological characterization showed that replacing ZnO in EPDM with proper ethylene content (75 %) with the lower content of ZnO (5 phr) in the recipes, resulted in lower cure time and higher scorch time and higher crosslinking density, which was further supported by Fourier transform infrared spectroscopy (FTIR). Mechanical properties before aging (elongation at break, tensile strength, and hardness) are greater with smaller content of ZnO. The value of percentage change of the properties after aging at 135 °C for 7 days, indicates that recipe D (Perkadox 14/40 (Di (tert-butyl peroxy isopropyl) benzene (DTBPIB)) peroxide cured EPDM has the best performance at tensile strength, and elongation at break. What is more, recipe D, containing 5 phr of ZnO exhibits the desired electrical performance. The paper provides sufficient experimental background to indentify the key physical aspects associated with each of the instabilities that occur at higher amounts of ZnO in formulation, and this in turns provides insight into different occurrences of each instability and how they can be minimized by reduction of ZnO in EPDM mixture.

Clozapine, ziprasidone, and sertindole-induced morphological changes in the rat heart and their relationship to antioxidant enzymes function

Atypical antipsychotics produce severe side effects including myocarditis that may be attributed to oxidative stress. The aim of this study was to investigate the influence of clozapine, ziprasidone, and sertindole on rat heart morphology and determine whether redox imbalane plays a role in development of histopathological changes. Adult 3-month-old male Wistar rats were treated with recommended daily dose for selected drugs. After 4 week treatment histopathological analysis of the heart was performed and expression and activity of antioxidant enzymes determined. All examined drugs induced histopathological changes that were characterized as toxic myocarditis. Degenerative changes in cardiomyocytes were accompanied by lymphocytic infiltration as well as pericardial histopathological alterations in all treated groups. The least prominent changes were observed in sertindole-treated animals, and most severe with clozapine. Clozapine increased superoxide dismutase 1 (SOD1) activity while ziprasidone reduced glutathione reductase (GR) activity. Sertindole exerted no marked effect on antioxidant enzyme function in the heart even though myocardial degeneration was noted. In conclusion, treatment with clozapine or ziprasidone induced pathophysiological alterations in rat heart, which appeared to be associated disturbances in antioxidant capacity. Abbreviation: AAP, Atypical antipsychotics; ROS, reactive oxygen species; SOD1, Copper-zinc superoxide dismutase; SOD2, Manganese superoxide dismutase; CAT, Catalase; GPx, Glutathione peroxidase; GR, Glutathione reductase; H&E, hematoxylin and eosin stain; TNF- α, tumor necrosis factor alpha.

Selenazolyl-hydrazones as Novel Selective MAO Inhibitors With Antiproliferative and Antioxidant Activities: Experimental and In-silico Studies

The novel approach in the treatment of complex multifactorial diseases, such as neurodegenerative disorders and cancer, requires a development of efficient multi-targeting oriented drugs. Since oxidative stress significantly contributes to the pathogenesis of cancer and neurodegenerative disorders, potential drug candidates should possess good antioxidant properties. Due to promising biological activities shown for structurally related (1,3-thiazol-2-yl)hydrazones, a focused library of 12 structurally related benzylidene-based (1,3-selenazol-2-yl)hydrazones was designed as potential multi-targeting compounds. Monoamine oxidases (MAO) A/B inhibition properties of this class of compounds have been investigated. Surprisingly, the p-nitrophenyl-substituted (1,3-selenazol-2-yl)hydrazone 4 showed MAO B inhibition in a nanomolar concentration range (IC₅₀ = 73 nM). Excellent antioxidant properties were confirmed in a number of different in vitro assays. Antiproliferative activity screening on a panel of six human solid tumor cell lines showed that potencies of some of the investigated compounds was comparable or even better than that of the positive control 5-fluorouracil. In-silico calculations of ADME properties pointed to promising good pharmacokinetic profiles of investigated compounds. Docking studies suggest that some compounds, compared to positive controls, have the ability to strongly interact with targets relevant to cancer such as 5′-nucleotidase, and to neurodegenerative diseases such as the small conductance calcium-activated potassium channel protein 1, in addition to confirmation of inhibitory binding at MAO B.

Effects of antipsychotic drug administration on antioxidative defense enzymes in male rat kidney

The use of atypical antipsychotic drugs (APD) was reported to be associated with adverse effects on the kidneys. Thus, the aim of this study was to examine whether APD exerted their adverse effects by interfering with the renal antioxidant defense system. Male 3-mo-old Wistar rats were treated for 28 d with ziprasidone (ZIP), clozapine (CLO), or sertindole (SER) using a daily dose recommended for antipsychotic drug therapy. The expression and activities of antioxidant enzymes superoxide dismutase (SOD) type 1 and type 2, catalase (CAT), glutathione reductase (GR), and glutathione S-transferases (GSTs) activity were measured in the kidneys. Changes in the kidneys were also evaluated histologically. Ziprasidone, CLO, and SER reduced renal SOD type 1 and type 2 activities. Decreased CAT activity was observed only in SER-treated rats. An inhibition in GR activity and increased activity of GST was found only after treatment with CLO. Histological analysis showed dilatation of proximal tubules in kidneys with all three drugs. In conclusion, data indicate that redox disturbances may contribute to renal morphologic alterations in proximal tubules in rats treated with all APD.

[APPROACH TO PATIENTS WITH GASTROINTESTINAL BLEEDING]

In the developed Western countries, despite the accumulation of knowledge about the causes and treatment of gastrointestinal bleeding, as well as the experience of gastroenterologists-endoscopists using sophisticated endoscopic devices, the number of hospitalizations and mortality rates has not declined as expected. The most likely explanations are the following: aging population, increased prevalence of alcoholic liver cirrhosis, gastroesophageal reflux disease and obesity, Helicobacter pylori antibiotic resistance, using dual anti-aggregation therapy, anticoagulants, and excessive use of nonsteroidal anti-inflammatory drugs. The aim of this paper is to show the incidence and the most common signs and symptoms of gastrointestinal bleeding. The aim is also to present initial clinical evaluation, diagnostic methods, the main causes of gastrointestinal bleeding, endoscopic hemostatic modalities and treatment of bleeding from the upper and lower gastrointestinal tract. Using the MEDLINE and Ovid databases, we searched the meta-analyses and systematic reviews published in English during the 2005-2015 period. Meta-analyses included results of randomized, double-blind studies on adults treated for gastrointestinal bleeding. Included were guidelines of the European and American Society of Gastroenterological Endoscopy, as well as recent expert work. In this review, we bring the state-of-the-art on gastrointestinal bleeding, new classification of gastrointestinal bleeding from the upper, mid and lower gut, controversy of nasogastric tube placement, use of prokinetic agents and inhibitor proton pumps in acute gastrointestinal bleeding from the upper tract, restrictive transfusion strategy, useful clinical stratification of the severity of bleeding, indications for hospitalization and outcome of using the clinical bleeding score, proper use of gastroprotection in patients at a high risk of peptic ulcer, the need of initial endoscopy, variceal assessment in newly diagnosed liver cirrhosis, primary and secondary prophylaxis of variceal bleeding, new endoscopic hemostatic modality, and radiological and surgical treatment of gastrointestinal bleeding. The educational nature of this review could serve for establishing Croatian guideline for the management of gastrointestinal bleeding.

Multiple signal classification for self-mixing flowmetry

For the first time to our knowledge, we apply the multiple signal classification (MUSIC) algorithm to signals obtained from a self-mixing flow sensor. We find that MUSIC accurately extracts the fluid velocity and exhibits a markedly better signal-to-noise ratio (SNR) than the commonly used fast Fourier transform (FFT) method. We compare the performance of the MUSIC and FFT methods for three decades of scatterer concentration and fluid velocities from 0.5 to 50 mm/s. MUSIC provided better linearity than the FFT and was able to accurately function over a wider range of algorithm parameters. MUSIC exhibited excellent linearity and SNR even at low scatterer concentration, at which the FFT's SNR decreased to impractical levels. This makes MUSIC a particularly attractive method for flow measurement systems with a low density of scatterers such as microfluidic and nanofluidic systems and blood flow in capillaries.

Effect of the optical system on the Doppler spectrum in laser-feedback interferometry

We present a comprehensive analysis of factors influencing the morphology of the Doppler spectrum obtained from a laser-feedback interferometer. We explore the effect of optical system parameters on three spectral characteristics: central Doppler frequency, broadening, and signal-to-noise ratio. We perform four sets of experiments and replicate the results using a Monte Carlo simulation calibrated to the backscattering profile of the target. We classify the optical system parameters as having a strong or weak influence on the Doppler spectrum. The calibrated Monte Carlo approach accurately reproduces experimental results, and allows one to investigate the detailed contribution of system parameters to the Doppler spectrum, which are difficult to isolate in experiment.

RELACIJE IZMEĐU GLOBE DIMENZIJA ORGANIZACIONE KULTURE I EMOCIONALNE INTELIGENCIJE ZAPOSLENIH U SRPSKIM ORGANIZACIJAMA

Jedna od karakteristika savremenih organizacija je stalna potrebaza promenama njihove organizacione kulture kao odgovor nadinamično organizaciono okruženje. Ova potreba je posebnoizražena u zemljama u tranziciji koje nisu bile pripremljene na oštrutržišnu utakmicu. Stoga brojni istraživači ispituju antecedentespremnosti na promene posebno menadžera u organizacijamakoji u najvećoj meri kreiraju organizacionu kulturu. Istraživanjaorganizacione kulture u zemljama u tranziciji zasnovana naprojektu GLOBE-a ukazala su na postojanje takozvanog„pendulum efekta” odnosno statistički značajne razlike izmeđupercipirane organizacione kulture i poželjne organizacione kulturemenadžera u organizacijama. Ovi rezultati ukazuju na „loše”fitovanje ličnosti i organizacije u tranzicionim zemljama uzimajućiu obzir činjenicu da su organizacione vrednosti, izražene krozpoželjnu organizacionu kulturu, važan deo ukupnog vrednosnogsistema menadžera. Prisustvo diskrepancije između percipiranei poželjne organizacione kulture smanjuje zadovoljstvoposlom, kvalitet radnih performansi i organizacionu privrženosta povećava verovatnoću da najbolji menadžeri napusteorganizaciju. Istraživanja su pokazala da su emocionalnointeligentni menadžeri najbolji „agenti” organizacionih promenai stoga je od naučnog i praktičnog interesa istražiti u kojoj jemeri emocionalna inteligencija prediktor željene organizacionekulture. Osnovni cilj našeg istraživanja je da se utvrdi u kojojmeri je emocionalna inteligencija prediktor željene organizacionekulture prema modelu GLOBE-ovog projekta. Projekat GLOBE(Globalno liderstvo i efektivnost organizacionog ponašanja) jedvadesetogodišnji projekat koji je okupio istraživače iz 62 zemljea istraživanje je obuhvatilo 18000 menadžera. Srbija nije bilauključena u ovaj projekat i ovo je jedno od prvih istraživanja unašoj zemlji koje treba da popuni ovu prazninu. Višegodišnjim istraživanjem učesnika u projektu GLOBE je identifikovano 9dimenzija organizacione kulture, među kojima su i one koje uodređenoj meri uopštavaju poznate dimenzije organizacionekulture uvedene od strane Hofstedea. Uzorak našeg istraživanjačini 224 srednjih menadžera iz 131 organizacije u Srbiji a rezultatipokazuju da ovi menadžeri preferiraju niži stepen distance moćii viši stepen orijentacije ka performansama, ka ljudima, kabudućnosti, izbegavanja neizvesnosti i institucionalnog i grupnogkolektivizma. Hijerarhijska regresiona analiza je pokazalada je upravljanje emocijama najbolji prediktor izbegavanjaneizvesnosti, samomotivacija je najbolji prediktor orijentacije kabudućnosti, upravljanje emocijama i samomotivacija su najboljiprediktori institucionalnog kolektivizma, empatija i samosvestsu najbolji prediktori performansne orijentacije, pol, samosvesti socijalne sposobnosti su najbolji prediktori organizacioneravnopravnosti polova a samomotivacija je najbolji prediktorasertivnosti. Dobijeni rezultati mogu biti korišćeni prilikomorganizacionih promena koje treba da pomognu u zadržavanjuemocionalno inteligentnih menadžera i razvoju njihove karijere,kao i prilikom selekcije menadžera.

Solving self-mixing equations for arbitrary feedback levels: a concise algorithm

Self-mixing laser sensors show promise for a wide range of sensing applications, including displacement, velocimetry, and fluid flow measurements. Several techniques have been developed to simulate self-mixing signals; however, a complete and succinct process for synthesizing self-mixing signals has so far been absent in the open literature. This article provides a systematic numerical approach for the analysis of self-mixing sensors using the steady-state solution to the Lang and Kobayashi model. Examples are given to show how this method can be used to synthesize self-mixing signals for arbitrary feedback levels and for displacement, distance, and velocity measurement. We examine these applications with a deterministic stimulus and discuss the velocity measurement of a rough surface, which necessitates the inclusion of a random stimulus.

Self-mixing laser Doppler flow sensor: an optofluidic implementation

We present the miniaturization of self-mixing interferometry (SMI) into a microfluidic circuit using an optical fiber, forming an optofluidic device that can be used as a component in lab on a chip systems. We characterize the performance of the device as a fluid velocity (and hence flow) sensor, showing it to produce good accuracy and correlation with theory over a range of velocities from 0.5 to 60  mm/s and almost four decades of scatterer concentration. SMI in an optofluidic system has the advantage that only a single path to the optical inspection point is needed, as the laser source is also the receiver of light. In addition, the same system that is used for measuring fluid velocity can be used to measure other quantities such as particle size. The configuration presented is inherently easy to optically align due to the self-aligned property of SMI and divergent nature of light exiting the embedded optical fiber, providing for low-cost manufacturing.

Approach to frequency estimation in self-mixing interferometry: multiple signal classification

Based on the nature of self-mixing signals, we propose the use of the multiple signal classification (MUSIC) algorithm in place of the fast Fourier transform (FFT) for processing signals obtained from self-mixing interferometry (SMI). We apply this algorithm to two representative SMI measurement techniques: range finding and velocimetry. Applying MUSIC to SMI range finding, we find its signal-to-noise ratio performance to be significantly better than that of the FFT, allowing for more robust, longer-range measurement systems. We further demonstrate that MUSIC enables a fundamental change in how SMI Doppler velocity measurement is approached, letting one discard the complex fitting procedure and allowing for a real-time frequency estimation process.

Effect of atypical antipsychotics on antioxidant enzyme activities in human erythrocytes (in vitro study)

OBJECTIVE

This study was set out to examine the impact of atypical antipsychotic drugs: aripiprazole, clozapine, ziprasidone, olanzapine, quetiapine, sertindole and amisulpride on the activity of antioxidant defence enzymes in human erythrocytes in vitro.

METHODS

Cu,Zn-superoxide dismutase (SOD1), catalase (CAT), selenium-dependent glutathione peroxidase and glutathione reductase activities were determined after drugs incubation with blood of 15 apparently healthy non-smoking male volunteers (ages 23-39) for 1 h at 37 °C.

RESULTS

A statistically significant increase in SOD1 activity was found in samples incubated with aripiprazole (p < 0.01) and quetiapine (p < 0.05) compared with incubated control. SOD1 activity profile following native polyacrylamide gel electrophoresis indicates that aripiprazole and quetiapine protect enzyme activity from inhibition with hydrogen peroxide. Our results showed that sertindole decreases activity of CAT comparing with control non-treated erythrocytes. Moreover, in sertindole treated erythrocytes, negative correlation between SOD1 and glutathione peroxidase activities was found. Increased amount of hydrogen peroxide in such situation may leave erythrocytes and transform their role in circulation from anti-oxidative to pro-oxidative.

CONCLUSIONS

Our results indicate that mechanism through sertindole could express its in vivo toxic effects and point toward possible (neuro)protective effects of aripiprazole and quetiapine.