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Possible applications of polymeric nitric oxide donors in treatment of murine experimental tumors
Horková, Veronika ; Šírová, Milada (advisor) ; Krulová, Magdaléna (referee)
Polymer-based drug delivery systems represent one of the promising strategies for successful tumor treatment. Conjugation of a low-molecular-weight drug to a syn- thetic polymer carrier enables targeted drug delivery to tumor tissue/cells and limited systemic toxicity of the drug. The conjugates show extended circulation time, and preferentially accumulate in tumor tissue due to the Enhanced Permeability and Re- tention (EPR) effect. The EPR effect depends on a structural anomaly in tumor neovasculature, and vasodilators were shown to enhance the EPR effect via an in- crease of blood supply in the tumor. Polymer drug carriers based on water-soluble N-(2-hydroxypropyl)methacrylamide (HPMA) benefit from variable architecture, drug loading and controlled release. HPMA-based conjugates with cancerostatics have al- ready proved high anti-tumor activity, inducing complete tumor regression followed by resistance to a second tumor challenge in experimental murine models. Three HPMA-based conjugates with organic nitrates (labeled 1, 2, and 3) were pre- pared as polymer donors of nitric oxide (NO) with the aim to intensify the EPR effect, thereby enhancing accumulation of co-administered macromolecular cancerostatics in the tumor. In this study, the conjugates were non-toxic to cancer cells and did not potentiate...
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Nitric oxide and its role in neurophysiology
Dobrovodská, Gabriela ; Otáhal, Jakub (advisor) ; Brime, Tufikameni (referee)
Title: Nitric oxide and its neurophysiologic role Objectives: The main aim of my diploma work is to evaluate the role of nitric oxide and its effects during epileptic seizure in rats. I summarize the present knowledge about nitric oxide and its effects on human organism in the theoretical section of this paper and I will suppose the positive effect of nitric oxide inhibitor in epileptic seizures in rats by the realization of my experiment. Methods: The experiment will be performed in the laboratory of Academy of Science of Czech Republic. Implementation will come through examining a set of ten rats. The first six will be given v (L-NPA) in an amount of 0,5mg to one side, which will take place by applying bilaterally to coele. Then after ten minutes 0,5µl of 4-aminopyridine (4-AP) will be applied bilaterally to coele. The control group, consisting of four rats will be given saline instead of L-NPA. The experiment will run for two days. Results: The course of epileptic seizure with application of L-NPA to examined group was compared with the control group. The experiment confirmed the positive effect of L-NPA in terms of delay and reduction of seizure. Keywords: nitric oxide, Nω -propyl-l-arginine, neurovascular coupling, 4-anopyridine, epilepsy
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Effect of nitric oxide on cerebral blood flow during neuronal activity
Strnadová, Petra ; Otáhal, Jakub (advisor) ; Brožíčková, Carole (referee)
Name of the thesis Effect of nitric oxide on cerebral blood flow during neuronal activity Aim of the thesis The aim of this thesis is to determine whether the application of 7-nitroindazole, relatively specific inhibitor of neuronal nitric oxide synthase, affects the baseline blood pressure. Furthermore, to determine whether the application of the substance affects the baseline cerebral blood flow and whether it influences blood flow in brain during transcallosal stimulation with increasing frequency. Research method The research took place at the premises of the Institute of Physiology, Academy of Sciences of the Czech Republic. Experiments were carried out on laboratory albino Wistar rats. The group contained both experimental and control sample. General anesthesia was performed to rats, stimulating and sensing electrodes were implanted in epidural area of sensorimotor cortex and Laser Doppler flow probe was implanted into the contralateral hemisphere. A plastic catheter was applied in the carotid artery for measuring systemic blood pressure. In the first part of the experiment, we tested the effects of 7-nitroindazole on the systemic blood pressure. In the second part of the experiment, we investigated the effects of 7-nitroindazole on baseline cerebral blood flow. The third part of the...
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Pharmacological modifications of potential signal systems regulating metabolism of adipocytes and hepatocytes and their influence on obesity
Hodis, Jiří ; Farghali, Hassan (advisor) ; Kršiak, Miloslav (referee) ; Otová, Berta (referee)
v anglickém jazyce: Thesis abstract: Background and aims: Both obesity and metabolic syndrome form severe health problems in the whole world. Nevertheless the armament of pharmacotherapy for both diseases remains unsatisfactory. We aimed our work to main organs in risk of the mentioned diseases -liver and visceral fat using hepatocytes and visceral adipocytes as model. We detected 3 main metabolic and signalization activities- glycogenolysis, Nitric oxide (NO) production and transcription of inducible NO synthase (iNOS) in hepatocytes, lipolysis, NO production and iNOS transcription rate in adipocytes. We directed our interest to combination of peroxisome proliferation activator receptor γ (PPARγ) agonist, antagonist and β3 adrenergic agonist in the culture of epididymal rat adipocytes in the first part of our work. While in the second part we investigated the influence of β and α adrenergic mimetics, adrenergic blockers in the culture of rat high glycogen content hepatocytes. Methods: NO production was detected under the active agents treatments by detection of NO oxidative products NO2 and NO3 in media. Glycogenolysis was measured as free glucose rise released by hepatocytes into the media. NOS transcription level was extrapolated after comparative polymerase chain reaction with reverse...
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Myocardial tolerance to ischemia/reperfusion injury - possible protective mechanisms
Alánová, Petra
Ischemic heart disease is the leading cause of death and disability worldwide. The effects of ischemic heart disease are usually attributable to the detrimental effects of acute myocardial ischemia/reperfusion (I/R) injury. The aim of the thesis was to contribute to current effort to clarify the basis of mechanisms that could save the heart from I/R injury. The whole thesis is based on four studies; while the first three are published, the fourth one has been under revision. In the first study, we proved the involvement of nitric oxide (NO) in the cardioprotective mechanism of chronic hypoxia (CH). We described that exogenously increased availability of NO as well as inhibition of phosphodiesterase type 5 led to increased myocardial tolerance of normoxic and chronically hypoxic rats. The effects of both interventions were not additive, suggesting that NO is included in cardioprotective signaling of CH. Second study continued in investigating molecular mechanisms underlying cardioprotection induced by CH. We showed that infarct size-limiting effect of adaptation to CH was accompanied by increased myocardial concentration of tumor-necrosis factor alpha (TNF-α) and TNF-α receptor R2. In the third study, we examined the effect of dexrazoxane (DEX), the only clinically approved drug against...
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Nanofiber materials simultaneously photogenerating NO and 1O2 species; Reversible NO binding on boron-containing clusters
Dolanský, Jiří
This project is concerned with the preparation of electrospun polystyrene (PS) nanofiber materials with covalently bonded NO-photodonor and electrostatically attached tetracationic porphyrinoid photosensitizers. These photofunctional nanofiber materials exhibit effective simultaneous photogeneration of small antibacterial NO and O2(1 ∆g) species under irradiation with daylight creating an antibacterial surface and near surrounding. NO species can be also generated just by gentle heating. Nanofiber materials were analyzed with SEM, FTIR, emission and UV/vis spectroscopy and time-resolved emission and absorption spetroscopy. The antibacterial effect was tested on Escherichia coli. The dual antibacterial action, in combination with the nanoporous character of the material that detains pathogens like bacteria on its surface, is ideal for any application where a sterile environment is neces- sary. The known bimetallic cluster system [(PMe2Ph)4Pt2B10H10] that possesses the propen- sity to reversibly bind small gaseous molecules (O2, SO2, CO) was synthesized in good yields for NO reversible binding investigation. Seven new monometallic precursors (Pt, Pd and Ni) to new bimetallic species were succesfully synthesized with the aim of future study of NO reversible binding. All new compounds were purified by...
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Molecular basis of endothelial sysfunction: endothelial nitric oxide synthase and heme oxygenase 1 genetic variations
Král, Aleš ; Martásek, Pavel (advisor) ; Baxová, Alice (referee) ; Schneider, Bohdan (referee)
Endothelial dysfunction is a pathologic state characterized by an altered equilibrium among vasodilatory and antithrombotic mediators and vasoconstrictive and prothrombotic mediators produced by the vascular endothelium. Multiple factors induce impaired production or increased consumption nitric oxide (NO), the key mediator of vascular homeostasis, produced by the nitric oxide synthase enzymes (NOS). Endothelial dysfunction represents one of the initial steps in the development of atherosclerosis, a chronic inflammatory disease of the vascular wall. The inducible enzyme heme oxygenase 1 (HO-1) represents one of the main cellular defense mechanisms against increased oxidative stress and decreased NO bioavailability accompanying endothelial dysfunction and atherosclerosis. We studied the genetic determinants of endothelial dysfunction and atherosclerosis by evaluating the association of the G894T endothelial NOS (eNOS) polymorphism and the HO-1 (GT)n promoter polymorphism with coronary artery atherosclerosis severity and risk profile and their evolution during hypolipidaemic treatment. In addition, we searched for genetic variations in exons 25 and 26 of eNOS gene, encoding the C-terminal part of the protein, deemed crucial for proper enzyme function and the 3'- untranslated region crucial for eNOS...
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The immune response of naïve mice infected with the neuropathogenic schistosome Trichobilharzia regenti
Macháček, Tomáš
Helminth neuroinfections represent a serious health issue, but the mechanisms of the host immune response often remain neglected despite the fact they might contribute to pathogenesis. This is partly due to the unavailability of clinical samples and the lack of suitable laboratory models. Herein, I focused on the characterization of several aspects of the immune response of mice infected with the neuropathogenic avian schistosome Trichobilharzia regenti. After the percutaneous infection of mice (accidental hosts), most T. regenti schistosomula are entrapped and eliminated in the skin, but the parasite antigens initiating the protective immune reaction are not known. Our in vitro experiments revealed that T. regenti cathepsin B2, a cysteine peptidase used for the skin penetration, activates bone marrow-derived dendritic cells much stronger than the parasite homogenate, suggesting its role in initiating the mixed type1/2 host immune response. However, some schistosomula manage to escape from the skin and continue their migration to the spinal cord. Here they crawl preferentially within the white matter which we demonstrated by the robust 3D imaging techniques, ultramicroscopy and micro-CT. The invasion of the spinal cord is accompanied by striking hypertrophy of astrocytes and microglia. We showed...
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The immune response of naïve mice infected with the neuropathogenic schistosome Trichobilharzia regenti
Macháček, Tomáš
Helminth neuroinfections represent a serious health issue, but the mechanisms of the host immune response often remain neglected despite the fact they might contribute to pathogenesis. This is partly due to the unavailability of clinical samples and the lack of suitable laboratory models. Herein, I focused on the characterization of several aspects of the immune response of mice infected with the neuropathogenic avian schistosome Trichobilharzia regenti. After the percutaneous infection of mice (accidental hosts), most T. regenti schistosomula are entrapped and eliminated in the skin, but the parasite antigens initiating the protective immune reaction are not known. Our in vitro experiments revealed that T. regenti cathepsin B2, a cysteine peptidase used for the skin penetration, activates bone marrow-derived dendritic cells much stronger than the parasite homogenate, suggesting its role in initiating the mixed type1/2 host immune response. However, some schistosomula manage to escape from the skin and continue their migration to the spinal cord. Here they crawl preferentially within the white matter which we demonstrated by the robust 3D imaging techniques, ultramicroscopy and micro-CT. The invasion of the spinal cord is accompanied by striking hypertrophy of astrocytes and microglia. We showed...
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The immune response of naïve mice infected with the neuropathogenic schistosome Trichobilharzia regenti
Macháček, Tomáš ; Horák, Petr (advisor) ; Bilej, Martin (referee) ; Schabussova, Irma (referee)
Helminth neuroinfections represent a serious health issue, but the mechanisms of the host immune response often remain neglected despite the fact they might contribute to pathogenesis. This is partly due to the unavailability of clinical samples and the lack of suitable laboratory models. Herein, I focused on the characterization of several aspects of the immune response of mice infected with the neuropathogenic avian schistosome Trichobilharzia regenti. After the percutaneous infection of mice (accidental hosts), most T. regenti schistosomula are entrapped and eliminated in the skin, but the parasite antigens initiating the protective immune reaction are not known. Our in vitro experiments revealed that T. regenti cathepsin B2, a cysteine peptidase used for the skin penetration, activates bone marrow-derived dendritic cells much stronger than the parasite homogenate, suggesting its role in initiating the mixed type1/2 host immune response. However, some schistosomula manage to escape from the skin and continue their migration to the spinal cord. Here they crawl preferentially within the white matter which we demonstrated by the robust 3D imaging techniques, ultramicroscopy and micro-CT. The invasion of the spinal cord is accompanied by striking hypertrophy of astrocytes and microglia. We showed...
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