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The use of LC/MS for the Study of Biotransformation of Xenobiotics in Helminths
Vokřál, Ivan ; Szotáková, Barbora (advisor) ; Lísa, Miroslav (referee) ; Horák, Petr (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate Mgr. Ivan Vokřál Supervisor Doc. Ing. Barbora Szotáková, Ph.D. Title of Doctoral Thesis The use of LC/MS for the study of biotransformation of xenobiotics in helminths Annually, parasites cause many losses regarding not only human lives but also the livestock. One of the most effective weapons that can be used against them are anthelmintics. However, in many cases anthelmintics cease to work and resistance development occurs. One of the possible mechanisms of resistance is the biotransformation of the drug to ineffective or less active products by the parasite. The aim of this work was to bring new knowledge about the biotransformation of drugs in helminths. Emphasis was given to the relationship between biotransformation and the resistance of parasites against anthelmintic drugs. A possible technique to achieve this goal is to study directly the products of biotransformation, i.e. metabolites. As this issue is nowadays most frequently solved by liquid chromatography and mass spectrometry, we used this technique to meet our goals. Biotransformation was studied in representatives of tapeworms, flukes and roundworms. Where possible, economically important representatives as Barber's pole...
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Rheumatic fever and its pharmacotherapy
Davidová, Kristýna ; Mladěnka, Přemysl (advisor) ; Vokřál, Ivan (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Candidate: Kristýna Davidová Supervisor: Dr. Mladěnka Přemysl, Ph.D. Title of thesis: Rheumatic fever and its pharmacotherapy Rheumatic fever (RH) is a systemic inflammatory disease occurring as a result of untreated tonsillopharyngitis caused by β-haemolytic streptococcus of group A. It is an autoimmune response, which leads to the production of antibodies against bacterial antigens, which also recognize human targets which are similar to M protein in the wall of the β-hemolytic streptococci and thus damage human tissue as well. Disease affects many organs such as joints, central nervous system, subcutaneous tissue and skin, but leaves lasting effects only on the heart. Usually not all symptoms are present, carditis and chorea are more common in children, arthritis in adults. Chronic rheumatic heart disease as a consequence of rheumatic carditis is associated with high morbidity and mortality in developing countries, where its incidence is the highest. There is no specific treatment for RH. We use only symptomatic treatment or preventive tools. Regime measures, including bed rest are also important in the case of acute rheumatic fever (ARH). Symptomatically, we use salicylates for ARH...
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Comparison of anthelmintics metabolism and activities of biotransformation enzymes in susceptible and resistant strains of Haemonchus contortus
Lasotová, Tamara ; Szotáková, Barbora (advisor) ; Vokřál, Ivan (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Tamara Lasotová Supervisor: Doc. Ing. Barbora Szotáková, Ph.D. Title of diploma thesis: Comparison of anthelmintics metabolism and activities of biotransformation enzymes in susceptible and resistant strains of Haemonchus contortus Haemonchus contortus is a predominant gastrointestinal parasite of sheep and goat. This blood-sucking parasite cause severe anaemia with mortalities, particularly in young animals. The greatest problem in pharmacotherapy of haemonchosis is a resistance to anthelmintics, which is worldwide. Biotransformation enzymes have the ability to inactivate anthelmintics via biotransformation and it contributes to development of helminths resistance. The aim of this project was to compare anthelmintics metabolism and activities of biotransformation enzymes in susceptible and resistant strains of H. contortus. For a testing three strains of H. contortus were chosen: anthelmintics-susceptible strain - ISE strain, benzimidazole-resistant strain - IRE strain, anthelmintics-resistant strain - WR strain. The results showed that the activities of reductases of carbonyl group of the model substrates are higher in resistant strains than in susceptible strain, on the contrary to...
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On pharmacokinetic of single administration of albendazole in mouflon (Ovis musimon)
Vokřál, Ivan ; Lamka, Jiří (advisor) ; Ducháček, Lubomír (referee)
Name: Ivan Vokřál Title: On pharmacokinetic of single administration of albendazole in mouflon (Ovis musimon) Abstract: This diploma thesis contributes to the knowledge of albendazole pharmacokinetics in mouflon (Ovis gmelini musimon) treated by a single administration of albendazole in a dose of 30,0 mg/kg of body weight. Two separate experiments were realised. The first one was carried out on 12 mouflon ewes divided into 4 groups. Groups of the animals were gradually culled at the time intervals of 4, 6, 8 and 10 hours after the albendazole administration. The samples of the blood (serum), bile from gallbladder and terminal bile ducts were withdrawn. The concentration of albendazole (ABZ) and its major metabolites albendazolsulphoxide (ABZSO) and albendazolsulphone (ABZSO2) were determined in samples of biological materials by HPLC method. To determine the ratio of ABZSO enantiomers, the HPLC method with chiral column was used. The second experiment carried on 2 animals (time interval 6 hours) extended and partially confirmed previous results. The increase in blood concentrations of albendazole and its metabolites until the eighth hour after the administration is evident. In later time intervals decrease in concentrations was documented. The concentrations of ABZSO and ABZSO2 between the bile...
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Differential reactivity of the longitudinal and circular muscle of the rat distal colon
Kubíčková, Růžena ; Vokřál, Ivan (advisor) ; Říha, Michal (referee)
(en) Charles University in Prague Faculty of Pharmacy Hradec Králové Department of Pharmacology Toxicology Student: Růžena Kubíčková Supervisors: Prof. Manuela Morato PharmDr. Ivan Vokřál, PhD. Title of diploma thesis: Differential reactivity of the longitudinal and circular muscle of the rat distal colon Physiological regulation of the function of the large intestine is neurohumoral. The neural part of this regulation implies the vegetative nervous system, which is crucial for the control of the gastrointestinal tract (GIT) motility. Concerning the humoral part of the regulation, recent studies showed that angiotensin II (Ang II) causes contraction of the colonic smooth muscle and, thus, can also influence the motility of the colon. However, there are no known studies that have described this process in detail. The aims of this work were (1) to compare the reactivity of the longitudinal and circular muscles of the rat distal colon to potassium chloride (KCl), acetylcholine (ACh) and Ang II, (2) to compare the observed results between male and female rats, and (3) to characterize the receptors mediating the response to Ang II. For purpose of the project, adult, 10-12 weeks old Wistar Han rats of both genders were used. Strips of the the rat distal colon were mounted in organ baths along their...
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Identification of metabolites of anthelminthics in helminth parasites using mass spectrometry
Komrska, Jan ; Vokřál, Ivan (referee) ; Skálová, Lenka (advisor)
If we want be successful in the treatment of parasitic disease, it is important to get the utmost information on the fate of given drug. The discovery of the metabolism of anthelmintics and in cosequence of participating enzymes can help us fight the rising resistance to given drugs. The aim of our work was to find and identify phase I and phase II metabolites of the anthelminthic drugs albendazole (ABZ), flubendazole (FLU) and mebendazole (MEB) formed in ex vivo incubations by parasitic helminth Dicrocoelium dendriticum, using liquid chromatography-mass spectrometric techniques. In the ex vivo study, D. dendriticum adults were incubated in cultivating medium in presence of benzimidazole drug for 24 hours. After incubation of parasites, both parasite homogenates and medium from the incubation were separately extracted using solid phase extraction. The extracts were analyzed using liquid chromatography-mass spectrometry (LC-MS). We detected in phase I albendazole sulphoxide, reduced flubendazole and reduced mebendazole. As for phase II metabolites, methylderivatives of flubendazole, reduced flubendazole and reduced mebendazole were observed.
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Defence mechanisms of lancet fluke against effects of anthelmintics
Ballóková, Anna ; Vokřál, Ivan (referee) ; Szotáková, Barbora (advisor)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Anna Ballóková Supervisor: Doc. Ing. Barbora Szotáková, Ph.D. Title of diploma thesis: Defence mechanisms of lancet fluke against effects of anthelmintics Dicroceliosis, helminthosis caused by Dicrocoelium dendriticum (lancet fluke), is worldwide spread infection of small ruminants. The only way of effective control of this parasitosis is in administration of anthelmintics. In lancet fluke, benzimidazole anthelmintic albendazole metabolism via enzymatic sulfoxidation was found but no information about albendazole oxidases is available. The aim of this work was to identify enzymes involved in the metabolism of albendazole in Dicrocoelium dendriticum isolated from naturally infected mouflons (Ovis musimon). To determinate the involved enzymes some of the specific inhibitors were used. The only effective inhibitors used in this work were α-nafthylthiourea and methimazole, specific inhibitors of flavin-containing monooxygenases. Indole-3-carbinole, used as the specific inhibitor of the same enzymatic system, was without any effect. Other inhibitors were used: 3-amino-1,2,4-triazole for catalase, diethyldithiocarbamate and octylamine for cytochrome P450 and salicylohydroxamic acid and...
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Viral hepatitides and their pharmacotherapy
Klímková, Martina ; Vokřál, Ivan (referee) ; Mladěnka, Přemysl (advisor)
15. Abstract Viral hepatitis belongs to the most common infectious diseases in the world by this time. Typical areas of their appearance are countries of South America, South Asia and Africa. They are transmitted parenterally (hepatitis B, C, D) or via the faecal-oral route (hepatitis A, E). Infection starts the immune reaction with production of antibodies that often serve in confirmation of the definitive diagnose. The clinical manifestation of viral hepatitis involves gastrointestinal discomfort, jaundice and actually liver failure and death if the hepatitis is complicated or untreated. Hepatitis A and hepatitis E don not become chronic and patients do not have any health consequences after recovery. Chronic forms of hepatitis B, C, and D cause long-lasting complications. There is no need to use antiviral drugs in the therapy of hepatitis A and E, the symptomatological therapy is sufficient. The other types of hepatitis demand an antiviral therapy. The basic of this therapy are interferon and synthetic nucleoside analogues. Interferons start an appropriate immune reaction and destroy infected hepatocytes and synthetic antivirotics inhibit synthesis of viral nucleic acid. In the treatment of hepatitis B is used pegylated interferon α, ordinarily in combination with nucleoside analogues (lamivudin,...
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Comparison between original and generic statin
Francová, Soňa ; Vokřál, Ivan (referee) ; Melicharová, Ludmila (advisor)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Candidate: Soňa Francová Supervisor: PharmDr. Ludmila Melicharová Title of diploma thesis: Comparison of the effects of original and generic statin One of the most common causes of death in the Czech Republic is cardiovascular disease. The treatment for the dyslipidaemia and the hyperlipoproteinemia is an apparent part of the primary as well as the secondary methods of prevention of the disease. A major break through in treatment was a discovery of the hypolipidemia group called statins fifteen years ago. The potential of statins is increasing due to continual discoveries of the extra-lipid effects which positively influence the yearly consummation of this substance. The research involves the comparison of the effects of the original medicament Zocor distributed by Merc & Co and the generic medicament Simgal produced by IVAX. The purpose of this work was to compare not only the efficiency of two medicaments but also their effectiveness on the level of cholesterol in the plasma. One year observations were implemented on two different groups with ten subjects in each group. The patients have been treated with the same dosage - 20 mg of medicament once a day. The research has been randomized,...
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Metabolism of anthelmintics in plants
Pavlík, František ; Szotáková, Barbora (advisor) ; Vokřál, Ivan (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: František Pavlík Supervisor: Prof. Ing. Barbora Szotáková, Ph.D. Consultant: RNDr. Radka Podlipná, Ph.D. Title of diploma thesis: Metabolism of anthelmintics in plants Anthelmintics enter into environment mainly through excretion of treated animals. They may cause a lot of adverse effects in ecosystem as they can affect non- target animals or they can accumulate in plants. Further, after consumption of these plants by livestock on pastures the resistence of helminths can be induced. Therefore, the present study was designed to find out biotransformation of frequently used anthelmintics flubendazole (FLU), albendazole (ABZ), fenbendazole (FBZ), ivermectine (IVM) and monepantel (MOP) by the common meadow plants harebell (Campanula rotundifolia) and plantain (Plantago lanceolata), which may often come into contact with anthelmintics through the excrements of treated animals. As model systems, suspensions of harebell and plantain cells and in vitro regenerants of plantain were used. There was no toxic effect of anthelmintics for these plants; they were able to metabolize anthelmintics into a wide scale of various compounds. These metabolites were identified by ultrahigh-performance liquid...
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