Drug metabolism is a specialised subset of xenobiotic metabolism, pertaining to the breakdown and elimination of pharmaceutical drugs. The enzymes involved in these pathways are the cytochrome P450 family of isozymes. Metabolism is an important factor in determining the pharmacological effects of drugs. The main aim of this study was to develop a system whereby the major metabolites of drugs can be produced in vitro. An in vitro system was developed and optimised using commercially prepared microsomes from rat liver and coumarin (by monitoring its conversion to 7-hydroxycoumarin) as a model. The optimum running conditions for the incubations were 50 μM coumarin, 50 μg protein/ml microsomes, 1 mM NADP⁺, 5 mM G6P and 1U/ml G6PDH incubated for 30 minutes at 38℃. The HPLC method for the detection of coumarin and 7-hydroxycoumarin was also validated with respect to linearity, reproducibility, precision, accuracy and lower limits of detection and quantification. The system developed was then tested using microsomes prepared from fresh bovine liver on these ten drugs of interest in doping control in horse racing: diazepam, nordiazepam, oxazepam, promazine, acepromazine, chlorpromazine, morphine, codeine, etoricoxib and lumiracoxib. The bovine liver microsomes were prepared using differential centrifugation and had activity on a par with the commercial preparations. This in vitro system metabolised the drugs and produced both phase I and II metabolites, similar to those observed in humans and horses in vivo. For example, the major metabolites of the benzodiazepine drug, diazepam, nordiazepam, temazepam and oxazepam as well as the glucuronidated phase II products were all found after incubations with the bovine liver microsomes. The metabolism of the drugs was also investigated in silico using the computational procedure, MetaSite. MetaSite was able to successfully predict known metabolites for most of the drugs studied. Differences were observed from the in vitro incubations and this is most likely due to MetaSite using only human cytochrome P450s for analysis.

Il est connu qu’une consommation modérée de vin rouge protégerait contre de nombreuses pathologies, du fait notamment de ses polyphénols. Nous avons étudié en particulier l’effet de ces polyphénols sur le cancer colorectal, l’un des cancers les plus fréquents dans les pays industrialisés. Certains polyphénols purifiés de vin rouge, comme le resvératrol et la quercétine, montrent des effets antiprolifératifs contre les cellules de cancer colorectal.Notre première approche a consisté à utiliser des extraits polyphénoliques de vins rouges de Bourgogne. Nous avons alors étudié d’une part, leurs effets in vitro sur la prolifération cellulaire de lignées tumorales colorectales humaines SW480 et les interactions entre ces polyphénols et le transport et le métabolisme du resvératrol ; et d’autre part, les effets in vivo chez la souris CF-1 d’une consommation régulière de ces polyphénols dans l’alimentation sur la survenue de lésions pré-néoplasiques chimio-induites par l’azoxyméthane au niveau du colon.Notre deuxième approche s’est orientée vers les modifications de la structure chimique du resvératrol. Par l’ajout de groupements méthoxyles et hydroxyles, et par l’isomérisation de sa structure (cis ou trans), nous avons cherché à dégager des relations structures-fonctions du resvératrol et à créer des dérivés plus bioactifs.Nous montrons que les polyphénols du vin rouge inhibent la prolifération de cellules cancéreuses coliques, en bloquant le cycle cellulaire. Certains polyphénols du vin tel que la quercétine sont capables d’augmenter la capacité des cellules SW480 à accumuler le resvératrol. [Nous montrons que] chez les souris, la prise régulière de polyphénols de vin rouge dans l’alimentation diminue le nombre global de lésions pré-néoplasiques, et surtout les lésions de grande taille dont dérivent les polypes intestinaux. Les modifications chimiques de la structure du resvératrol montrent que les analogues méthoxylés du cis-resvératrol sont de puissants antiprolifératifs par blocage de la mitose, alors que le mécanisme d’action des dérivés du trans-resvératrol bloque le cycle cellulaire au niveau de la phase S.Ce travail supporte l’idée que le recours aux polyphénols du vin dans la prévention des adénocarcinomes coliques est possible et que ce champs de recherche est une voie prometteuse. Concernant des visées thérapeutiques, la recherche d’analogues du resvératrol présentant une biodisponibilité accrue est une piste à poursuivre / It is known that moderate consumption of red wine may protect against many diseases, in particular because of its polyphenols. We studied in particular the effect of these polyphenols on colorectal cancer, one of the most common cancers in industrialized countries. Some purified polyphenols from red wine, like resveratrol and quercetin, showed antiproliferative effects against colorectal cancer cells.Our first approach was to use polyphenolic extracts from Burgundy red wine. We then studied their in vitro effects on human colorectal tumor cell lines SW480’s proliferation and the interactions between the polyphenols and the transport and metabolism of resveratrol; and secondly, the effects on CF-1 mice of regular consumption of these polyphenols in the diet on the occurrence of chemically induced pre-neoplastic lesions by azoxymethane in the colon.Our second approach was directed towards changes in the chemical structure of resveratrol. By the addition of hydroxyl and methoxyl groups, and the isomerization of its structure (cis or trans), we wanted to identify structure-function relationships of resveratrol and create more bioactive derivatives.We show that the red wine polyphenols inhibit proliferation of colon cancer cells by blocking the cell cycle. Some wine polyphenols such as quercetin are able to increase the ability of SW480 cells to accumulate resveratrol. [We show that] in mice, the regular intake of red wine polyphenols in the diet reduces the overall number of pre-neoplastic lesions, especially large lesions which may become intestinal polyps. The chemical changes in the structure of resveratrol show that the methoxylated analogues of cis-resveratrol are potent antiproliferatives by blocking mitosis, while the mechanism of action of derivatives of trans-resveratrol blocks the cell cycle at the S phase.This work supports the idea that the use of wine polyphenols in the prevention of colon adenocarcinomas is possible and that this field of research is a promising way. Concerning therapeutic purposes, the search for analogues of resveratrol with improved bioavailability is a way to pursue

Magister Pharmaceuticae - MPharm / The aim of this study was to investigate the mechanism of fenfluramine-induced pulmonary phospholipidosis, by comparing the profile and levels of induced phospholipids in the rat and the mode of phospholipase inactivation, both relative to that produced by chlorphentermine. Wistar and BD9 rats were injected with fenfluramine (FF) and chlorphentermine (CP) intra-peritoneally daily over a six week period to induce phospholipidosis. The lungs isolated from such treated and untreated animals, were grouped into unlavaged lungs and lungs to be lavaged and from the latter group the alveolar macrophages were isolated. Small sections of the unlavaged lungs were microscopically examined to verify the induction of phospholipidosis. Further the levels of phosphatidyl choline (PC), spingomyelin (SPM), phosphatidyl ethanolamine (PE), phosphatidyl glycerol (PG), phosphatidyl inositol (PI), phosphatidyl serine (PS) and phosphatidic acid (PA) were determined in both groups of lungs using a TLC method. To assess whether the drug-mediated inactivation of the phospholipases (PL) occurred via direct inhibition of the enzymes or via the drug-phospholipid complex, the hydrolysis of the above phospholipids by PL-A or PL-C were monitored using colorimetric methods. The feasibility of the phospholipid-drug complex-mediated mechanism was further explored, by assessing the effect the two drugs had on the phase transition temperature of the phospholipids. Electron microscopy revealed the presence of hypertrophied and elevated counts of alveolar macrophages in the treated-Wistar and -BD9 rats. In the FF- and CP treated Wistar and BD9 rats there were, compared to the saline-treated rats, a 200 % and 235 % increase in macrophage counts, respectively, for the FF-treated rats and a 700 % and 965 % increase in macrophage counts, respectively, for the CP treated rats. The levels of all the phospholipids in the unlavaged lungs of both rat strains were elevated, except that for PG, PS and PA. In both rat strains following the treatment with both drugs the PG levels were not elevated and the PS levels were not elevated following CP treatment. Following the treatment for both drugs, the PA levels were also not elevated in the BD9 rats. Relative to the levels found in the unlavaged lungs of the control rats, the increases ranged from a minimum of 9 to a maximum of 216 %. In general, Wistar rats appeared to be more susceptible to both FF and CP treatment. In both rat strains, lavaging of the lungs considerably reduced the levels of phospholipids remaining in the lung and the differences between the treated and untreated animals became less striking. The addition of FF or CP, whether directly to the enzyme, or in the form of the drug phospholipid complex, resulted in significant decreases in the PL-A-mediated or PL-C-mediated hydrolysis of virtualy all the test phospholipids. The average decrease ranged from 0.811 to 4.04 ,.,.FFAbbb ,.,.1-1sample min-I, for the PL-A activity and 0.023 to 0.827 ,.,.gIp'CC100 ,.,.1-1 sample min-I, for the PL-C activity. In the case of FF, the inhibition of PL-A activity could not be ascribed exclusively to either direct inhibition of the enzyme or reduced susceptibility of the phospholipid substrate-drug complex. The PL-C activity appeared to be inhibited to a greater extent via the phospholipid substrate-drug complex rather than by direct inhibition. On the other hand, CP induced a small, but significantly greater degree of inhibition of PL-A activity, more via direct inhibition, rather than by the phospholipid substrate-drug complex. The PL-C activity appeared to be inhibited to a greater extent via phospholipid substrate-drug complexation than by direct inhibition. From the above data, considered collectively, it was not possible to declare either of the two possible mechanisms as the more likely one for FF or CP-induced inhibition of the phospholipases. The feasibility of the indirect mode was further explored, by determining the phase transition temperatures for the phospholipid-drug complexes of each drug. The addition of each drug caused a depression of the phase transition temperature of all the phospholipids with a .1T'dd ranging from 0.52 to 15.73 °C. This appears to support the notion that both drugs bind to the phospholipids and the differences in the extent of the phase transition temperature depression of the individual phospholipids may indicate differences in the binding capacities of these drugs. The following major conclusions may be drawn from the results of this investigation. Fenfluramine induces a phospholipidosis syndrome in the lungs of Wistar and BD9 rats that are histologically similar to that induced by CP. It induces the elevation of essentially the same phospholipids as CP, primarily in the alveolar spaces and macrophages, and by implication, most likely via similar mechanisms. For both FF and CP, both direct inhibition and phospholipid-drug complex-mediated inhibition of phospholipases were found to be a viable mechanism for this syndrome. The mechanism for FF-induced pulmonary phospholipidosis thus appears to be similar to that of CP; small quantitative differences in essentially similar mechanisms, may explain the differences in the levels of induced phospholipidosis found in this study.

L’appréhension des mécanismes d’action biologiques des protéines membranaires nécessite de comprendre les interactions des xénobiotiques avec ces protéines et avec les membranes lipidiques. Les méthodes expérimentales sont parfois coûteuses et ne permettent d’obtenir que des informations partielles sur les interactions xénobiotiques-membrane-protéine. La modélisation moléculaire est une sérieuse alternative. Les simulations de dynamique moléculaire et de dynamique biaisées ont ouvert de nombreuses perspectives en permettant de décrire ces interactions moléculaires à l’échelle atomique. Grâce à des simulations de dynamique moléculaire, nous avons été capables de construire un modèle de transporteur humain ABC : ABCC4/MRP4. Cette protéine a été choisie pour sa présence dans le rein, notamment, et son importance clinique. Nous avons évalué l’influence du cholestérol sur cette protéine. L’étude de domaines spécifiques et l’impact d’un polymorphisme a été reliée à l’activité de transport de cette protéine. Nous avons également étudié l’interaction de xénobiotiques avec ce transporteur humain. Le cycle de transport des transporteurs ABC a été examiné afin de comprendre leur fonctionnement. L’incorporation de cholestérol a montré un impact significatif sur la protéine humaine ABCC4/MRP4 et sur les xénobiotiques étudiés. L’importance de domaines constituant la protéine ABCC4/MRP4 ainsi que l’importance de résidus individuels a clairement été prouvée. Nous avons également pu observer des intermédiaires du cycle de transport d’un transporteur ABC conjointement avec des changements structuraux. / Understanding the biological mechanisms of action of membrane proteins requires the comprehension of the interactions of xenobiotics with these proteins and with lipid membranes. Experimental methods are often demanding and only partially respond to xenobiotic-membrane-protein interactions. In silico molecular modeling is a serious alternative to tackle these issues. Molecular dynamics (MD) and biased dynamics simulations have opened many perspectives by providing an atomistic description of these intermolecular interactions. Using MD simulations, we built a model of the human ABC ABCC4/MRP4 transporter. We explored the influence of cholesterol on this protein as well as the impact of a polymorphism known to shut down the transport activity of this protein. We also studied the interaction of xenobiotics with this human transporter. The transport cycle of the ABC transporters was investigated in an attempt to better understand how it works.Interactions between lipid membranes and xenobiotics were explored by examining their ability to incorporate lipid membranes. Lipid mixtures with cholesterol showed a significant impact on the human protein ABCC4/MRP4 and on the xenobiotics studied. The importance of regions, domains constituting the ABCC4/MRP4 protein as well as the importance of specific residues has been clearly demonstrated. We also observed intermediates in the transport cycle of an ABC transporter in conjunction with structural changes occurring during this cycle.

<p>Fokus ove doktorske disertacije je bilo izučavanje sorpcionog pona&scaron;anja tri herbicida koji se nalaze na listi prioritetnih supstanci prema Okvirnoj Direktivi o vodama EU (2000/60/EC) sa generalnim ciljem dobijanja podataka korisnih za prioritizaciju na osnovu novog fundamentalnog znanja o efikasnosti (ad)sorpcije za uklanjanje ovih<br />supstanci iz&nbsp; vode u lokalno specifičnim uslovima. Odabrani su ksenobiotici različite rastvorljivosti, hidrofobnosti i donorsko-akceptorskih osobina, koji&nbsp; pripadaju&nbsp; različitim klasama&nbsp; herbicida (dinitroanilinski-trifluralin, hloroacetamidni-alahlor i triazinski-&nbsp; atrazin). Prva faza je obuhvatala karakterizaciju sorbenata i vodenih matriksa .U sintetičkom matriksu, trifluralin pokazuje veći afinitet na ispitivanim sedimentima u odnosu na alahlor i atrazin. I u slučaju organoglina, sorpcija je najizraženija za trifluralin. Alahlor i atrazin pokazuju slične sorpcione kapacitete na TMA-K, dok je na TMA-B, sorpcija izraženija za alahlor u odnosu na atrazin. U&nbsp; zavisnosti od prirodnog matriksa, na oba sedimenta, najveće&nbsp; Kd vrednosti su dobijene za trifluralin, dok su Kd vrednosti za atrazin i alahlor&nbsp; bile veoma slične ili&nbsp;pak veće za atrazin. U slučaju organoglina, vrednosti&nbsp; K_d su rasle sa porastom log&nbsp; K_OW vrednosti herbicida na TMA-K u oba prirodna matriksa. Kada je u pitanju TMA-B, rast K_dvrednosti sa rastom log&nbsp; K_OW vrednosti uočava se u povr&scaron;inskom matriksu pri C_e&nbsp; = 0,05 mg/l i 0,5 mg/l, i podzemnom matriksu pri najvećoj ravnotežnoj koncentraciji C_e&nbsp; = 0,5 mg/l. Kao najefikasniji sorbenti su se pokazali&nbsp; TMA-B&nbsp;(Kd&nbsp; = 10,5 -&nbsp; 483 l/kg) i model sediment (Kd = 16,4 -&nbsp; 761 l/kg). Odsustvo jasne linearne korelacije izmeĎu&nbsp; Kd i&nbsp; % TOC upućuje na važnost interakcija mineralne faze i herbicida. U slučaju sedimenata nisu utvrđene korelacije K_d sa log&nbsp; K_OW&nbsp;vrednostima, dok kod organoglina one postoje. K<span id="cke_bm_184S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_184E" style="display: none;">&nbsp;</span> /K_OW odnosi su najveći kod atrazina na svim sorbenti<span id="cke_bm_185E" style="display: none;">&nbsp;</span>ma pa se pretpostavlja da on najvi&scaron;e učestvuje u&nbsp; uspostavljanju specifičnih interakcija zbog svojih donorsko-akceptorskih osobina. &Scaron;to se tiče uticaja DOC,&nbsp; zaključuje se da poreĎenje efikasnosti sorbenata treba sprovoditi u prirodnim matriksima jer sorpcioni koeficijenti variraju u zavisnosti od&nbsp;koncentracije polutanata, tipa i sadržaja DOC. Kolonskim eksperimentima je pokazano da atrazin i alahlor prolaze kroz kolonu sedimenta, dok je trifluralin skoro u potpunosti adsorbovan i u vrlo maloj koncentraciji detektovan u efluentu &scaron;to je u saglasnosti sa rezultatima &scaron;aržnih eksperimenata na ovom sorbentu. Procenjeni faktor retardacije pomoću modela TransMod za atrazin je veći u prirodnim matriksima (R <span id="cke_bm_190S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_190E" style="display: none;">&nbsp;</span> = 54 i R_d = 55 u podzemnoj i povr&scaron;inskoj vodi, redom) nego u sintetičkoj&nbsp;vodi (R_d = 40). Kod alahlora nisu uočene značajne promene faktora retardacije meĎu matriksima (R_d = 30-35). Ovi rezultati su suprotni očekivanjima na osnovu hidrofilnosti ksenobiotika i mogu biti&nbsp; rezultat upravo interakcija sa organskim materijama koje su bile izražene u kolonskim testovima, verovatno i vi&scaron;e nego u &scaron;aržnim testovima gde se nije pojavilo povećanje R_d vrednosti u prirodnim matriksima u odnosu na sintetički matriks.&nbsp; Bez obzira &scaron;to je&nbsp; alahlor hidrofobniji od atrazina, u uslovima datog matriksa i sorbenta ispoljava slične (&scaron;aržni testovi) ili<br />slabije sorpcione karakteristike&nbsp; (kolonski testovi)&nbsp; koje upućuju na mobilnost kroz prvi za&scaron;titini sloj.&nbsp; Treća faza je obuhvatala ispitivanje adsorpcije herbicida na aktivnim ugljevima u prahu. Ispitana je kinetika adsorpcionog procesa određivanjem koeficijenta za unutarčestični prenos mase herbicida u sirovim i ozoniranim prirodnim matriksima. Određena je efikasnost uklanjanja herbicida na razlilčitim ugljevima u prahu. Efikasnost uklanjanja se kretala u različitim opsezima u zavisnosti od odabranog uglja, vodenog matriksa i doze uglja. Na komercijalnim ugljevima najveća postignuta efikasnost (doza uglja od 15 mg/l) za&nbsp; alahlor iznosi u povr&scaron;inskoj vodi 95%, a u podzemnoj 76%. Za atrazin to je u povr&scaron;inskoj vodi 58% i u podzemoj vodi 56%, a za trifluralin u povr&scaron;inskoj vodi 87%, a u podzemnom matriksu 92%. Na uglju sitnih čestica koji se koristi u kombinaciji sa membranskom filtracijom ove<br />vrednosti su&nbsp; i veće. Stepen uklanjanja DOC na komercijalnim ugljevima (pri dozi od 15 mg/l) iznosi do 57% za povr&scaron;inski matriks i do&nbsp; 51% za podzemni matriks. Slična efikasnost u uklanjanju DOC je postignuta i na uglju sitnih čestica u oba matriksa. Ozonizacija je ispoljila očekivan negativan uticaj, vi&scaron;e ili manje izražen. U slučaju ksenobiotika, uticaji ozonizacije su bili različiti, u zavisnosti od primenjenog uglja, matriksa i supstance. Najizraženiji uticaj je kod alahlora,&nbsp; i to u negativnom smislu,<br />zbog pada efikasnosti uklanjanja, verovatno zbog kompeticije sa organskom materijom ili efekta solubilizacije. U nekim slučajevima, ali mnogo manje, taj efekat je primećen i kod trifluralina. Na oba komercijalna uglja primećen je pozitivan uticaj ozonizacije na uklanjanje atrazina, ali u različitim matriksima,&nbsp; pa se može spekulisati<br />pretpostavljanjem da dolazi do favorizovane raspodele u novim oblogama&nbsp; POM na uglju formiranim nakon ozonizacije koje su i dovoljno adsorbabilne, ali i sa dovoljno reaktivnim osobinama za asociranje sa polarnim supstancama, &scaron;to je delimično i potvrđeno rezultatima adsorpcione analize.&nbsp;&nbsp;</p> / <p>The focus of&nbsp; this doctoral thesis was the study of the sorption behavior of three herbicides which are on the list of priority substances according to Water Framework Directive (2000/60/EC). The aim&nbsp; was&nbsp; to obtain the&nbsp; data useful for prioritization on the basis of the&nbsp; new fundamental knowledge about (ad) sorption efficiency&nbsp; for the removal of these substances from the&nbsp; locally specific water matrices. Selected xenobiotics&nbsp; were&nbsp; differing&nbsp; in&nbsp; solubility, hydrophobicity, and donor-acceptor properties, which belong to different classes of compounds(trifluralin as herbicide, alachlor as chloracetamide herbicide and atrazine as triazine herbicide).&nbsp; In the first phase&nbsp; of the thesis&nbsp; characterization&nbsp; of sorbents and water matrices&nbsp; was performed. The aim of the second phase was the testing&nbsp; of&nbsp; the sorption and<br />desorption of organic xenobiotics in the sediments and organoclays. The equilibrium&nbsp; sorption parameters and removal efficiencies of herbicides were determined in different water matrices.&nbsp; In the synthetic matrix, trifluralin showed a higher sorption affinity onto tested sediments in comparison to the alachlor and atrazine. In the case of organoclays, sorption was mostly&nbsp; pronounced for trifluralin. Alachlor and atrazine have similar sorption capacities onto the TMA-K. For the TMA-B, the sorption was more pronounced for alachlor than atrazine. Depending on the natural water matrices,&nbsp; the highest&nbsp; K_d values were obtained for trifluralin onto both sediments. The&nbsp; K_d values for atrazine and alachlor were very similar or even greater for atrazine. In the case of organoclays, K_d values increased with increasing log&nbsp; K_OW values of herbicides onto TMA-K in both natural matrices. When it comes to TMA-B,&nbsp; K_d&nbsp; valuesincreased with increasing log&nbsp; K_OW values in&nbsp; the surface matrix for<br />C_e = 0,05 mg/l and 0,5 mg/l, and in groundwater at the highest equilibrium&nbsp; concentration&nbsp; C<span id="cke_bm_506S" style="display: none;">&nbsp;</span>_e<span id="cke_bm_506E" style="display: none;">&nbsp;</span>&nbsp; = 0,5 mg/l. TMA-B (K_d = 10,5&nbsp; -&nbsp; 483 l/kg) and model&nbsp; sediment&nbsp; (kd= 16,4 to 761 l/kg) were the most efficient s<span id="cke_bm_507E" style="display: none;">&nbsp;</span>orbents. The absence of&nbsp; the&nbsp; clear linear correlation between&nbsp; K_d and % TOC&nbsp; indicates the importance of the interaction of mineral phases and herbicides. Correlation between K<span id="cke_bm_513S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_513E" style="display: none;">&nbsp;</span> and K_OW values did not existed in the case of sediments,&nbsp; contrary to the organoclays.&nbsp; Since K<span id="cke_bm_519S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_519E" style="display: none;">&nbsp;</span> /K_oW ratios were the h<span id="cke_bm_520E" style="display: none;">&nbsp;</span><span id="cke_bm_514E" style="display: none;">&nbsp;</span>ighest for atrazine onto all sorbents, it&nbsp; was&nbsp; assumed that atrazine mostly participate in specific interactions due to its donor-acceptor properties. Regarding the&nbsp; influence of DOC on sorption, it was concluded that a comparison of sorbents efficiencies should be carried in&nbsp; native matrices as sorption coefficients vary depending on the concentration of pollutants, the type and content of DOC. Column&nbsp; experiments showed that atrazine and alachlor passed through the column of the sediment, while the trifluralin almost completely was adsorbed and in very low concentrations detected in the effluent which is in accordance with the results of the&nbsp; batch experiments.&nbsp; Estimated retardation factors of atrazine were higher in natural matrices (R<span id="cke_bm_525S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_525E" style="display: none;">&nbsp;</span>= 54 and R_d = 55 in groundwater and surface water, respectively) than in&nbsp; the synthetic water (R_d= 40_{). I}n the case of alachlor, retardation factors were similar among water matrices (R_d = 30-35). These results are in the opposition&nbsp; based on the xenobiotic hydrophilicity, and they could be the consequence of interaction with the organic matter&nbsp; present&nbsp; in the column tests, probably more than in the batch tests. Estimations of&nbsp; R_d based on batch tests&nbsp; did not show an increase of R_d values in natural matrices, in comparison to the synthetic matrix. More hydrophobic alachlor, in the circumstances of the sorbent matrix exerts similar&nbsp; (batch&nbsp; tests) or lower sorption (column tests) characteristics that indicate mobility through the first protective layer.<span id="cke_bm_526E" style="display: none;">&nbsp;</span> The third phase&nbsp; included herbicide adsorption tests onto powdered activated carbons. The adsorption kinetics was examined by determining the intraparticle mass transfer coefficients for herbicides in raw and ozonated natural water matrices. The removal efficiencies of herbicides for different powdered activated carbons were determined. Removal efficiencies were in different ranges depending on the selected carbon, water matrix and carbon dose. The highest removal efficiencies&nbsp; for commercial carbons (for carbon dose of 15&nbsp; mg/l)&nbsp; for&nbsp; alachlor were 95% and 76% in surface and groundwater, respectively. The highest&nbsp; removal of atrazine was&nbsp; 58% in surface water and 56% in groundwater. In thecase of trifluralin, removal efficiencies were&nbsp; 87% in surface water and 92% in groundwater. The removal efficiencies for the carbon with fine particles&nbsp; (usually&nbsp; used in combination with a membrane filtration)&nbsp; were greater. The removal of DOC&nbsp; &nbsp; by&nbsp; commercial carbons (at the dose of 15 mg/l) was less than 57% in the surface water and 47% in groundwater. A similar efficiency in DOC removal was achieved for the carbon with fine particles in both water matrices. Ozonation showed the expected &nbsp; negative influence on&nbsp; DOC&nbsp; removal efficiencies, more or less pronounced. In the case of xenobiotics, ozonation influence was different, depending on the applied carbon and xenobiotic. The most important negative influence was&nbsp; in the case of alachlor probably due to competition with organic matter or solubilization effect. The&nbsp; same, but less pronounced effect was observed for trifluralin. The positive influence of ozonation was observed in removal of atrazine&nbsp; by&nbsp; both commercial carbons but in &nbsp; different water matrices.&nbsp; One can speculate that it comes to the favorable distribution in new NOM coatings on carbons formed upon ozonation, which are sufficiently adsorbable, but with enough reactive qualities for association with polar substances, which is partly confirmed by the results of adsorption analysis.</p>

Earlier this decade, “bath salts” were popularized as legal alternatives to the pyschostimulants cocaine and the amphetamines. These products contained synthetic cathinones including 3,4-methylenedioxypyrovalerone (MDPV), 4-methylmethcathinone (mephedrone), and 3,4-methylenedioxymethcathinone (methylone). Studies indicate that the cathinones have similar pharmacology to controlled psychostimulants, increasing levels of dopamine (DA) in the synaptic cleft. Most preclinical investigations have only assessed the effect of these synthetic cathinones independently; however, case reports and DEA studies indicate that “bath salts” often contain mixtures of these substances. Therefore, in a recent study by our laboratory, we examined effects of individual versus combined exposure to MDPV, mephedrone, and methylone. Interestingly, an enhanced effect on the levels of DA was observed, as well as significant alterations in locomotor activity following co-exposure to the cathinones. In this study, we examine whether the enhanced effects of the drug combination were due to pharmacokinetic (PK) interactions. It is known that many of the same cytochrome P450 (CYP) isoenzymes metabolize each of these three drugs. Therefore, it is probable that the drugs’ PK would differ when administered individually as compared to in combination. We hypothesize that combined exposure to MDPV, mephedrone, and methylone will result in increased drug concentrations and enhanced total drug concentrations when compared to individual administration. The pharmacokinetics of MDPV, mephedrone, and methylone in the brain and plasma were examined following intraperitoneal injection in mice. Briefly, adolescent male Swiss-Webster mice were injected intraperitoneally with either 10 mg/kg MDPV, 10 mg/kg mephedrone, 10 mg/kg methylone, or 10 mg/kg combined MDPV, mephedrone, and methylone. Following injection, brains and plasma were collected at the following time points: 1, 10, 15, 30, 60, and 120 minutes. Samples were then flash-frozen and stored at -70°C until analysis. Drugs were extracted via solid-phase extraction and concentrations were determined using a previously validated and published high pressure-liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Following intraperitoneal administration, all drugs quickly crossed the blood-brain barrier and entered the brain. Peak drug concentrations, time to peak concentration, drug half-lives, and total drug exposure (as measured by area under the curve) are compared when drugs were given individually versus in combination. These data provide insight into the consequences of co-exposure to popular “bath salt” products.

An unprecedented rise in the availability of new synthetic drugs of abuse has been observed in the recent years. One of the most noted cases is that of a popularized designer drug mixture known as ‘bath salts’. Commonly obtained from various shops and on the internet, “bath salts” often contain the synthetic cathinones 3,4 methylenedioxypyrovalerone (MDPV), mephedrone, and methylone in diverse combinations. Individually, the synthetic cathinones are known to have similar pharmacology to controlled psychostimulants such as cocaine and the amphetamines, increasing the levels of dopamine (DA) in the synaptic cleft. DA is an important neurotransmitter that regulates a variety of behaviors and functions; neurons within the mesolimbic DA pathway (ventral tegmental area to nucleus accumbens) are involved in reward and motivation and are activated by these drugs of abuse. Additionally, psychostimulant-induced increases in DA in the nigrostriatal pathway (substantia nigra to corpus striatum) lead to increases in locomotor behavior. However, the majority of preclinical investigations have only assessed the effects of individual bath salt constituents and have provided little information regarding the possibility of significant drug interactions with the co-exposure of MDPV, mephedrone, and methylone. This study sought to evaluate and compare the effects of individual versus combined MDPV, mephedrone, and methylone on dopamine (DA) levels in discrete brain regions as well as motor stimulant responses in mice. Male adolescent Swiss-Webster mice received intraperitoneal injections of saline, MDPV, mephedrone, methylone (1.0 or 10.0 mg/kg), or the cathinone cocktail (MDPV + mephedrone + methylone at 1.0, 3.3, or 10 mg/kg). The effect of each treatment on DA and DA metabolite levels in mesolimbic and nigrostriatal brain tissue was quantified 15 min after a single exposure utilizing high pressure liquid chromatography with electrochemical detection (HPLC-ECD). Additionally, locomotor activity was recorded in mice after acute (day 1) and chronic intermittent (day 7) dosing. The results demonstrate that MDPV, mephedrone, and methylone produce dose-related increases in the mesolimbic and nigrostriatal DA levels that are significantly enhanced following their co-administration. Additionally, a decrease in locomotor activity on day 1 that was exacerbated by day 7 was noted in mice treated with the cathinone cocktail and was not observed with any of the single agents. The decrease in locomotor activity was accompanied by an increase in stereotypic-like behavior including excessive grooming and even self-mutilation. Our findings demonstrate a significantly enhanced effect of MDPV, mephedrone, and methylone on both DA and its metabolites resulting in significant alterations in locomotor activity. This work provides insight into the potential enhanced risk of the use of these combination synthetic cathinone products.

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2016. / Generally, aluminium (Al) is required as a micronutrient by plants. The metabolism of Al within the plant can exert a number of effects within the plant. These include: interfering with cell division in both root tips and lateral roots, increasing cell wall rigidity, maintaining the correct cellular redox state, as well as the various other physiological and growth responses. Al is one of the most abundant elements in the earth’s crust and becomes toxic in many plants when the concentration is greater than 2-3 ppm, where the soil has a pH<5.5. Iron (Fe) is an equally important element, and the toxicity of this metal possesses constraints primarily on wetland plants growing in acidic soils that have high reducible iron content. The impact of metal toxicity (Al and Fe) requires an understanding of many aspects related to Al and Fe uptake, transport and distribution by plants in wetland ecosystems. In this study, three species of Cyperus viz. Cyperus alternifolius, Cyperus prolifer and Cyperus textilis were used to carry out phytotoxicity tests to monitor xenobiotic substances.

No description available.

Insights into the modes of action (MoAs) of xenobiotics are of utmost importance for the definition of adverse outcome pathways (AOPs), which are essential for a mechanism-based risk assessment. A well-established strategy to reveal MoAs of xenobiotics is the use of omics. However, often an even more comprehensive approach is needed, which can be achieved using multi-omics. Since the immune system plays a central role in the defense against foreign substances and pathogens, with the innate immune system building a first barrier, we systematically reviewed multi-omics studies investigating the effects of xenobiotics on macrophages. Surprisingly, only nine publications were identified, combining proteomics with transcriptomics or metabolomics. We summarized pathways and single proteins, transcripts, or metabolites, which were described to be affected upon treatment with xenobiotics in the reviewed studies, thus revealing a broad range of effects. In summary, we show that macrophages are a relevant model system to investigate the toxicological effects induced by xenobiotics. Furthermore, the multi-omics approaches led to a more comprehensive overview compared to only one omics layer with slight advantages for combinations that complement each other directly, e.g., proteome and metabolome.