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1	Strukturne promene sluzokože debelog creva pacova pod uticajem akrilamida / Structural changes of rat colon mucose after acrylamide treatment Koledin Ivana 08 July 2016 (has links) <p>Akrilamid je supstanca koja se prirodno stvara pečenjem i prženjem hrane bogate skrobom.  Cilj rada je bio da se ispita subhronični i akutni uticaj akrilamida na debelo crevo prepubertalnih pacova. Dobijeni rezultati su pokazali da akrilamid ne naru&scaron;ava morfologiju zida creva, ali dovodi do promena u volumenskoj gustini njegovih tunika i lamina. Najizraženije promene  su bile na  vezivnom tkivu  debelog creva.  Analizom peharastih ćelija  i sadržaja mucina pokazano je da akrilamid utiče i na ugljenohidratnu i na proteinsku komponentu mucina. Subhronični tretman je  doveo do smanjenja broja limfocita i  eozinofila, a  kod akutnog tretmana  je primećeno nakupljanje limfocita i eozinofila u kolonu akrilamidom tretiranih jedinki. Broj mastocita je u sva tri eksperimenta bio smanjen kod tretiranih životinja. Duže izlaganje akrilamidu ima imunosupresivno dejstvo kod pacova.</p> / <p>Acrylamide is natural product of cooking (baking, roasting) starchy food.  Aim of the study was to evaluate the risk of subchronic and acute acrylamide treatment on juvenile  rat colon.  Changes  in colon wall morphology was detected by stereological methods since histological evaluation reveal normal colon architecture  after acrylamide intoxication.  The changes was  most prominent on  connective tissue of rat colon.  Acrylamide affected both protein  component of mucins and glycans linked to peptide backbone.  In subchronic  treatment acrylamide caused reduction of lymphocytes  and eosinophils  number, while acute experiment lead to lymphocytes  and  eosinophils  accumulation in colon tissue. Acrylamide intoxication decreased mast cell number in all experiments. Longer acrylamide exposure had immunosuppressive effect in rats.</p>
2	Uticaj subhroničnog tretmana akrilamidom na histološke i biohemijske karakteristike jetre juvenilnih mužjaka pacova / Histological and biochemical features of theliver in juvenile male rats following subchronicacrlyamide exposure Kovac Renata 08 July 2016 (has links) <p>Akrilamid (CASR No. 79-06-1) predstavlja veoma reaktivni, hidrosolubilni monomer za koji se smatra da ima toksične i potencijalno kancerogene efekte po zdravlje ljudi. &Scaron;tetne posledice akrilamida i njegovog jo&scaron; reaktivnijeg metabolita, glicidamida, su dokazane kod eksperimentalnih životinja i podrazumevale su neurotoksičnost, genotoksičnost i kancerogenost. Epidemiolo&scaron;ke studije rađene na ljudima pokazale su da akrilamid izaziva neurotoksične efekte, dok se genotoksičnost i kancerogenost jo&scaron; smatraju potencijalnim efektima, a zasnivaju se na podacima koji su dobijeni u okviru istraživanja na laboratorijskim životinjama. Njegove &scaron;tetne posledice na jetru, posebno kod mladog organizma, jo&scaron; uvek nisu dovoljno istražene.</p><p>Akrilamid se spontano formira u hrani koja je bogata ugljenim hidratima, tokom termičke obrade namirnica na visokim temperaturama. Ovaj monomer se formira tokom tzv. neenzimatske Mallard-ove reakcije, kojom se dobijaju smeđe komponente u hrani. U namirnicama ovaj monomer se formira reakcijom između redukujućih &scaron;ećera (uglavnom glukoze ili fruktoze) i aminokiseline (dominantno asparagina).</p><p>Imajući na umu da je jetra centralni organ za metabolizam akrilamida, ovo istraživanje  je imalo za cilj da ispita glavne histolo&scaron;ke i biohemijske promene na jetri juvenilnog organizma pacova, nakon njegove subhronične ekspozicije akrilamidu. Istraživanje je  rađeno na 3 eksperimentalne grupe peripubertalnih/juvenilnih mužjaka Wistar pacova, od kojih su dve bile tretirane vodenim rastvorom akrilamida u dozi od 25 ili 50  mg/kg telesne mase, dok je treća grupa služila kao kontrola i primala destilovanu vodu. Životinje su bile tretirane oralno, putem gavaže, 5 dana nedeljno, tokom 3 nedelje. Nakon 24 h od poslednjeg tretmana, životinje su uvedene u etarsku  anesteziju i dekapitovane, a zatim su prikupljeni krv i uzorci tkiva jetre.</p><p>Tkivo jetre je uzeto iz srednjeg lobusa, fiksirano u 10% neutralnom puferisanom  formalinu tokom 24 h i obrađeno prema standardnom protokolu za parafinsko kalupljenje. Ukalupljeni uzorci jetre su zatim isečeni na serijske preseke tkiva debljine 5 µm, a zatim bojeni histohemijskim i imunohistohemijskim metodama. Uzorci krvi su pripremljeni za serolo&scaron;ku analizu. </p><p>Histolo&scaron;ka analiza preseka bojenih hematoksilin-eozin (H&E) metodom nije  zabeležila prisustvo značajnih razlika u op&scaron;toj arhitekturi jetre i njenoj lobularnoj  organizaciji među eksperimentalnim grupama. Stereolo&scaron;ka analiza je ukazala na  <br />mikrostrukturne promene kod hepatocita i jetrinih sinusoida. Rezultati sugeri&scaron;u, na dozno-zavisno povećanje volumena hepatocita, njihove citoplazme i nukleusa, i doznozavsino smanjenje volumena sinusoida, u odnosu na kontrolne uzorke jetre.</p><p>Analiza glikogena je rađena na presecima jetre bojenim metodom Periodic acid–<br />Schiff-a (PAS), gde se uočilo smanjenje količine glikogena u grupi tretiranoj nižom  dozom akrilamida, dok je u grupi tretiranoj većom dozom uočena njegova <br />akumulacija, u odnosu na kontrolne životinje.</p><p>Imunopozitivnost hepatocita na marker proliferacije, Ki-67, bila je smanjena u grupi pacova tretiranoj nižom dozom, a bila povećana u grupi tretiranoj većom dozom akrilamida pri komparaciji sa kontrolom. Stereolo&scaron;ki nalazi su potvrdili inicijalnu histolo&scaron;ku analizu.</p><p>Imunopozitivnost hepatocita na marker apoptoze, Caspase 3, je bila smanjena <br />kod obe grupe životinja tretiranih akrilamidom u odnosu na kontrolu. Nasuprot tome, <br />imunopozitivnost neparenhimskih ćelija jetre, pretežno Kupffer-ovih ćelija, je bila <br />uvećana u obe tretirane grupe pri komparaciji sa kontrolom.</p><p>Imunopozitivnost Kupffer-ovih ćelija na marker CD68 je bila smanjena u uzorcima jetre kod oba tretmana akrilamidom u odnosu na kontrolu.</p><p>Populacija mastocita, prikazana toluidine-blue (TB) metodom bojenja, bila je uvećana  kod obe grupe pacova tretiranih akrilamidom u poređenju sa kontrolom. Povećanje brojnosti ovih ćelija je bilo posebno prominentno kod njihove degranulisane  subpopulacije. Stereolo&scaron;ka analiza je potvrdila histolo&scaron;ke nalaze. </p><p>Serumska analiza je pokazala uvećanu aktivnost aspartat aminotrasferaze (AST) i <br />smanjenu aktivnost alanin aminotrasferaze (ALT) kod obe grupe životinja tretiranih  <br />akrilamidom u odnosu na kontrolu. Aktivnost alkalne fosfataze (ALP) je bila uvećana <br />u grupi tretiranoj nižom dozom, a smanjena u grupi tretiranoj većom dozom <br />akrilamida, u odnosu na kontrolu. Vrednosti koncentracije ukupnih serumskih proteina kao i koncentracije C reaktivnog proteina (CRP) nisu pokazale značajnije promene među eksperimentalnim grupama.</p><p>Oba akrilamidna tretmana su izazvala gubitak telesne mase kod tretiranih pacova, u odnosu na kontrolne životinje. Postojeći podaci ukazuju prominentni hepatotoksični potencijal akrilamida koji može poremetiti mikrostrukturne osobine i funkcionalni status hepatocita kod jetre mladog organizma. Akrilamid može značajno poremetiti funkcionalnost jetre, obzirom da se promene na celularnom nivou mogu relativno brzo odraziti na nivo tkiva, a kasnije ugroziti i homeostazu celog organizma.</p> / <p>Acrylamide  (CASR No. 79-06- 1)  is highly reactive, water-soluble monomer which is considered as toxic and potentially cancer causing chemical to humans. Adverse health effects regarding acrylamide and its more reactive metabolite,glycidamide, were detected in experimental animals, and  included neurotoxicity, genotoxicity, and   carcinogenicity.  Human epidemiological studies claim that acrylamide has neurotoxic effects, while  genotoxicity and carcinogenicity are considered as  potential human health risks only on the basis of animal studies. Its harmful effects on the liver, especially in a young organism, are still to be elucidated.</p><p>Acrylamide  is spontaneously formed in  carbohydrate-rich food during high-temperature  processing. It is  formed during heat-induced non-enzymatic reaction, also known as  the Maillard browning reaction, between reducing sugars (glucose and fructose), and free amino acids (mainly asparagine).</p><p>Having in mind  that  acrylamide  metabolism takes place in a liver,  the study aimed to investigate the main histological and  biochemical changes in the liver of juvenile rat following subchronic acrylamide intoxication. Study was performed on peripubertal/juvenile male Wistar rats, divided in 3 experimental groups, two of which were treated with acrylamide in doses of 25 or 50 mg/kg of body weight, while the third group served as the control and received distilled water. Animals were treated orally, via gavage, 5 days a week, during 3 weeks. Animals  were anesthetized by   ether inhalation and decapitated 24 hrs after the last treatment.</p><p>Liver tissue was sampled from the middle lobe, fixed in  10% neutral  buffered formalin for 24 hrs,  routinely processed for paraffin  embedding  and cut into 5-µm thick serial sections for subsequent histochemical and immunohistochemical staining.Blood samples were collected for subsequent biochemical analysis .</p><p>Histological examination of haematoxylin and eosin (H&E) stained sections did not point to any major alteration in main in liver lobular architecture or organization among the experimental groups. Stereological analysis revealed a microstructural changes in hepatocytes and liver sinusoids. The analysis detected a dose-dependant increase in the volume of hepatocytes, their cytoplasm and nuclei, and dose-dependant decrease in the volume of liver sinusoids compared to the control, respectively.</p><p>Glycogen analysis was performed on Periodic acid–Schiff (PAS) stained sections which showed glycogen reduction in the low-dose group, and its accumulation in the high-dose group, compared to the control, respectively.</p><p>Imunopositivity in hepatocytes for Ki-67 protein, a known marker for proliferation, showed a decrease in low-dose group, while in high- dose group was detected its increase compared to the control, respectively. Stereological analysis confirmed initial histological observation.</p><p>Caspase 3 immunopositivity, a known marker for apoptosis, proved to be decreased in hepatocytes in both acrylamide-treated groups when compared to the control. One the other hand, immunopositivity was increased in non-parenchymal  cell, predominantly in Kupffer cells, in comparison to the control. Immunopositivity for CD68, a marker for Kupffer cells, proved to be decreased in both acrylamide-treated groups when compared to the control.</p><p>Population of the mast cells, visualized on toluidine blue (TB) stained sections, showed its increase in both acrylamide-treated groups, in comparison to the control. The increase was especially prominent regarding a degranulated subpopulation of these cells. Subsequent stereological analysis confirmed histological findings.</p><p>Serum analysis showed increased  activity of  aspartate aminotransferase (AST), and decreased  activity  of alanine aminotransferase (ALT) in  both AA-treated groups, while the  activity  of alkaline phosphatase (ALP)  was increased in low-dose, but   decreased in high- dose group compared to the control, respectively.  The concentration of total serum proteins as well as concentration of C reactive protein (CRP) did not show any major changes among the experimental groups.</p><p>Body weight measurements showed that all acrylamide-treated rats lost their body weight as opposed to the control rats whose body mass increased.</p><p>Present results suggest a prominent hepatotoxic potential of acrylamide which might alter the microstructural features and functional status in hepatocytes of  immature liver.  Acrylamide may cause significant perturbation in liver functionality which may be reflected from cellular to the tissue level, thereby endangering the whole body’s homeostasis.</p>
3	Uticaj tretmana akrilamidom na endokrini pankreas pacova / Effect of acrylamide treatment on endocrine pancreas of the rats Stošić Milena 22 June 2018 (has links) <p>Akrilamid  je toksična hemijska supst anca koja je već dugi niz godina prisutna u životnoj sredini,  jer se kao važan monomer koristi u različite industrijske i laboratorijske svrhe. U poslednjih petnaest godina, akrilamid je postao posebno zanimljiv za &scaron;ire naučne krugove jer  se pokazalo da  se  nalazi  i u  hrani  biljnog porekla, posebno hrani bogatoj skrobom, koja se priprema pečenjem ili prženjem na temperaturama vi&scaron;im od 120°C.  Do sada ustanovljeni negativni zdravstveni efekti akrilamida su veoma raznovrsni i mogu biti rezultat delovanja samog  akrilamida ili delovanja njegovog metabolita glicidamida koji nastaje  in vivo  kada se jedan deo molekula akrilamida metaboli&scaron;e oksigenacijom dvostruke veze pomoću enzima citohrom P450 2E1 (CYP2E1). Akrilamid je supstanca koja ima dokazan negativan efekat  na organske sisteme kod ljudi i životinja, i koja je svrstana u moguće humane karcinogene. Negativan efekat akrilamida na egzokrini pankreas je poznat, ali o mogućim efektima akrilamida na endokrini pankreas se i dalje veoma malo zna. Ima puno dokaza koji  ukazuju na to da akrilamid ima citotoksični efekat koji se  manifestuje kroz uticaj na redoks-status ćelija i dovodi do promena u vrednostima biomarkera oksidativnog i nitrozativnog stresa, kao i u aktivnosti antioksidativnih enzima. Pankreas  je  jedan od ciljnih  organa za delovanje akrilamida te je  glavni predmet istraživanja  doktorske teze  bio proučavanje potencijalnog efekta akrilamida na endokrini pankreas pacova.  Ispitivanje je vr&scaron;eno na 3  eksperimentalne grupe  juvenilnih  mužjaka pacova soja Wistar,  od kojih je  jedna grupa bila kontrolna, dok su dve bile tretirane  sa akrilamidom u dozama od 25 mg/kg tm i 50 mg/kg tm,  5 dana nedeljno,  tokom 3 nedelje. Po isteku tretmana,  nakon dekapitacije, kompletno tkivo pankreasa  je  fiksirano u 10% rastvoru formalina  tokom  24  h i obrađeno prema  standardnoj proceduri za kalupljenje u parafinu.  Parafinski kalupi su sečeni na serijske preseke debljine 5 µm, nakon čega su bojeni  histohemijskom i imunohistohemijskim metodama.  Kod eksperimentalnih grupa posmatrane  su  histolo&scaron;ke promene na endokrinom pankreasu, sa akcentom na α-  i β-ćelije.  Takođe, posmatrana je  i  ekspresija  hormona insulina i glukagona, enzima inducibilne azot -oksi d  sintetaze (iNOS) i  CYP2E1,  kao  i ekspresija   antioksidativnih enzima  katalaza  (CAT) i superoksid dismut aza 1 i 2  (SOD1 i SOD2)  u ćelijama Langerhansovih ostrvaca. Potencijalna promena u funkcionalnosti β-ćelija je ispitana i kroz analizu nivoa glukoze u serumu pacova tretiranih sa akrilamidom.<br />Budući da β-ćelije čine 80% ćelija koje grade Langerhansova ostrvca pankreasa,  pored in vivo  eksperimenata, ispitana  je  i toksičnost akrilamida na  Rin-5F ćelijsku liniju insulinoma β-ćelija pacova u in vitro uslovima. Glavni cilj in vitro  istraživanja je bio  da se  ispita  uticaj  rastućih  koncentracija akrilamida na preživljavanje tretiranih  Rin-5F  ćelija, ali i efekat IC<sub>50</sub>  koncentracije ove supstance primenjene  tokom  različitih vremenskih intervala  (0,5, 1, 3, 6, 12 i 24 h)  na pojavu oksidativnog i nitrozativnog stresa. Redoks-status Rin-5F ćelija tretiranih  sa akrilamidom je ispitan preko analize prisustva biomarkera oksidativnog i nitrozativnog stresa, akrivnosti CAT i ukupne SOD, kao i promene u ekspresiji gena za CAT, SOD1, SOD2   i iNOS.  Pored toga, analiziran je i efekat istog tretmana na  ekspresiju gena za insulin, CYP2E1, Bax i Bcl-2. U okviru teze je pokazano da akrilamid ne dovodi do  značajnih promena u histolo&scaron;koj građi, dijametru i broju Langerhansovih ostrvaca  kod  tretiranih životinja.  Primena stereolo&scaron;kih metoda  je  ukazala  na mikrostrukturne promene na  endokrinom pankreasu na nivou α-  i β-ćelija. U ovoj tezi je po prvi put pokazano da tretman akrilamidom negativno utiče na broj i povr&scaron;inu β-ćelija pankreasa.  U tezi je, takođe,  pokazan  značajan dozno-zavisni pad u prisustvu insulina u β-ćelijama   pankreasa. Uprkos  tome, kod  akrilamidom tretiranih  životinja  nije konstatovana  promena  u  koncentraciji serumske glukoze.  U  ovoj tezi je pokazano da tretman akrilamidom dovodi do   statistički značajnog porasta  u broju α-ćelija  kod životinja koje su primale nižu dozu tretmana, dok se  broj α-ćelija  kod životinja koje su primale vi&scaron;u dozu tretmana  ne razlikuje značajno od kontrole.  Tretman akrilamidom je doveo do značajnog  porasta u količini   prisutnog glukagona  u α-ćelijama pankreasa.<br />Tretman akrilamidom nije doveo do značajne promene u ekspresiji CAT, SOD1 i SOD2 u ćelijama Langerhansovih ostrvaca.  Kod  tretiranih životinja  do&scaron;lo do značajnog dozno-zavisnog porasta  u ekspresiji  enzima iNOS,  dok je ekspresija  CYP2E1 značajno dozno-zavisno opala  nakon tretmana. U  tezi je pokazano da tretman akrilamidom negativno utiče na vijabilnost Rin-5F ćelija, i utvrđeno je da IC50  koncentracija akrilamida za Rin-5F ćelije iznosi 10 mM.  Rezultati teze pokazuju da tretman akrilamidom u IC<sub>50</sub>  koncentraciji u Rin-5F ćelijskoj liniji značajno povećava nivo malondialdehida (MDA) nakon tretmana u trajanju od 1, 12 i 24 h.  Isti tretman  značajno smanjuje nivo redukovanog GSH nakon tretmana od 1, 3, 6, 12 i<br />24 h, kao i nivo slobodnih  –SH grupa nakon tretmana od 3 i 6 h. Tretman akrilamidom u IC<sub>50 </sub> koncentraciji signifikantno pojačava aktivnost CAT nakon tretmana od 1 h, dok tretman u trajanju od 12 h značajno smanjuje aktivnost ovog enzima. Ovaj tretman smanjuje aktivnost SOD nakon 1, 12 i 24 h, dok  tretman u trajanju od 6 h značajno pojačava aktivnost enzima SOD.  U tezi je, takođe, pokazan i veoma značajan porast  u nivou prisutnih nitrita,  koji  je direktno proporcionalan  sa nivoom azot-oksida i nivoom akivnosti enzima iNOS.  Ovaj  nalaz ukazuje na potencijalnu pojavu nitrozati vnog stresa u akrilamidom-tretiranim Rin-5F ćelijama.  U  tezi je po prvi put pokazano da tretman  akrilamidom dovodi do  značajnih  varijacija  u transkripciji gena za iNOS, SOD1, SOD2,  CAT,  CYP2E1,  Bax i Bcl-2 u tretiranim Rin-5F ćelijama, dok isti tretman ne dovodi do  promene nivoa  transkripcije gena za insulin.  Tretman akrilamidom u koncentraciji od 10<br />mM tokom rastućih vremenskih perioda dovodi do porasta u relativnoj količini iRNK<br />gena za iNOS u svim tačkama tretmana, do porasta  nivoa  iRNK za SOD1 i SOD2 nakon tretmana od 12 i 24 h, kao i do porasta  količine  iRNK za CAT nakon tretmana od 3 h.  U  tezi je pokazano  i  da akrilamid  izaziva  promene  u sintezi  iRNK  za enzim  CYP2E1  koji je  posebno značajan u kontekstu detoksikacije ove toksične supstance.  Porast u transkripciji gena za  CYP2E1  je uočen  nakon tretmana u trajanju od 0,5 i 1 h, dok je  do smanjenja transkripcije  do&scaron;lo  nakon tretmana od 12  i 24  h.  Tretman akrilamidom u koncentraciji od  10 mM tokom rastućih vremenskih perioda dovodi do porasta u relativnoj količini iRNK  gena za Bax u svim tačkama tretmana, i do porasta u transkripciji gena za Bcl-2 nakon tretmana od 0,5, 1 i 3 h.<br />Sumirajući  sve  rezultate  ove teze,  moze se zaključiti  da je endokrini pankreas  jedno od  ciljnih tkiva, na koje akrilamid ostvaruje vi&scaron;estruki negativni uticaj.</p> / <p>Acrylamide is a toxic chemical used as an important monomer for various industrial and laboratory purposes, which makes it highly present in the environment. In the last fifteen years, acrylamide has become especially interesting for wider scientific circles when it was found in staple foodstuff rich in starch, prepared at temperatures higher than 120°C. The established negative health effects of acrylamide are very diverse and can be the result of the acrylamide action itself or the action of its metabolite glycidamide that occurs in vivo, when acrylamide molecule is metabolized via oxygenation of the double bond by the cytochrome P450 2E1 (CYP2E1). Acrylamide is a substance with a proven adverse effect on humans and animals, and it is classified as a possible human carcinogen. The negative effect of acrylamide on the exocrine pancreas has already been recognized, but the possible effects of acrylamide  on endocrine pancreas are still mostly undetermined. There is a significant amount of evidence to suggest that acrylamide exerts a cytotoxic effect which manifests through the changes in level of oxidative and nitrosative stress biomarkers, as well as in the activity of antioxidant enzymes. Since, pancreas is one of the target organs for acrylamide, the main subject of doctoral thesis was to investigate the potential effect of acrylamide on the rat endocrine pancreas. The investigation was conducted on 3 experimental groups of juvenile male Wistar rats, of which one group was the control group, while two groups were treated with acrylamide at doses of 25 mg/kg bw and 50 mg/kg bw, 5 days a week, during 3 weeks. After termination of the treatment, decapitation was performed, and the complete pancreatic tissue was fixed in a 10% formalin solution for 24 h and treated according to the standard paraffin embedding procedure. Paraffin molds were cut into 5 μm thick serial sections, after which they were stained with histochemical and immunohistochemical methods. Histological changes ofthe endocrine pancreas, with the emphasis on α- and β-cells, were examined in three experimental groups of rats. In addition, the expression of insulin and glucagon hormone, the inducible nitric oxide synthase (iNOS) and CYP2E1 enzymes, and the expression of antioxidative enzymes catalase (CAT) and superoxide dismutases 1 and 2  (SOD1 and SOD2) in the islets of Langerhans were also investigated. A potential change in the functionality of β-cells was also examined by analyzing glucose level in the serum of rats treated with acrylamide. In pancreatic islets of Langerhans the majority of cells (>80%) are β-cells. Therefore, in addition to in vivo experiments, the toxicity of acrylamide was examined in vitro on rat insulinoma Rin-5F cell line.The main goal of in vitro research was to investigate the impact of increasing acrylamide concentrations on the viability of treated Rin-5F cells, and also to examine whether IC50 concentration of this substance, applied at different intervals of time (0.5, 1, 3, 6, 12 and 24 h), induce oxidative and nitrosative stress. Redox-status of Rin-5F cells treated with acrylamide was examined by analyzing oxidative and nitrosative stress biomarkers, CAT and total SOD activity, as well as changes in the expression of the CAT, SOD1, SOD2 and iNOS. In addition, the effect of the same treatment on the transcription of the insulin, CYP2E1, Bax and Bcl-2 gene was analyzed.The results of the thesis showed that acrylamide treatment does not lead to significant changes in the histological structure, diameter and number of islets of Langerhans of treated animals. Application of stereological methods indicated microstructural changes of α- and β-cells ofendocrine pancreas. It has been shown for the first time that treatment with acrylamide negatively affects the number and surface area of pancreatic β-cells. In addition, a significant dose-dependent decline in the amount of insulin in pancreatic β-cells was also demonstrated. However, no change in serum glucose level was observed in treated animals. Acrylamide treatment led to a statistically significant increase in the number of α-cells in animals receiving a lower dose of treatment, while the number of α-cells in animals receiving a higher dose of treatment did not differ significantly from the control. Treatment with acrylamide led to a significant increase in the amount of the glucagon in α-cells. Treatment with acrylamide did not cause a significant change in the expression of CAT, SOD1 and SOD2 in islets of Langerhans. However, there was a significant dosedependent increase in the  expression of iNOS enzyme, whereas expression of CYP2E1 significantly decreased in dose-dependent manner in treated animals. Results of the thesis showed that acrylamide exerts a negative effect on the viability of Rin-5F cell line. It has been established that the IC50 concentration of acrylamide for the Rin-5F cell line is 10 mM. The results of the thesis indicate that treatment of Rin-5F cell line with IC50 concentration of acrylamide for 1, 12, and 24 h significantly increased the level of malondialdehyde (MDA). Exposure to acrylamide for 1, 3, 6, 12 and 24 h significantly decreased the level of reduced GSH, while the level of free -SH groups was reduced after 3 and 6 h of acrylamide treatments. Treatment with IC50 concentration of acrylamide significantly enhanced CAT activity after 1 h of acrylamide exposure, while 12 h exposure significantly reduced the activity of this enzyme. Application of acrylamide reduced SOD activity after 1, 12, and 24 h exposure, while 6 h exposure significantly increased the activity of SOD enzymes. Results of the thesis also showed a very significant increase of the nitrite level, which is directly proportional to the level of nitrogen oxide (NO) and the level of the iNOS activity. This finding points to the potential occurrence of nitrosative stress in acrylamide-treated Rin-5F cells. It has been shown for the first time that acrylamide treatment leads to significant variations in transcription of iNOS, SOD1, SOD2, CAT, CYP2E1, Bax and Bcl-2 genes in treated Rin-5F cells, while the same treatment does not affect transcription of the insulin gene. Treatment with acrylamide at a concentration of 10 mM for increasing periods of time leads to an increase in the relative amount of the iNOS gene iRNA at all treatment points. Twelve and and 24 h of acrylamide exposure increased the transcription of the SOD1 and SOD2 genes. Transcription of CAT gene was increased after 3 h  ofacrylamide exposure. Furthermore, it has been shown that acrylamide treatment leads to variations in the mRNA synthesis of CYP2E1 gene, which is particularly significant in the context of detoxification of this toxic substance. An increase in the transcription ofthe CYP2E1  gene was observed after 0.5 and 1 h of acrylamide exposure, while the reduction of  transcription occurred after 12 and 24 h of acrylamide exposure. The treatment with 10 mM acrylamide has led to an increase of the transcription of the Bax gene at all treatment points, and also to an increase of transcription of the Bcl-2 gene after of 0.5, 1, and 3 h of acrylamide exposure. Summarizing all the results of this thesis, it can be concluded that the endocrine pancreas  is one of the target tissues of acrylamide, to which this substance exerts a multiple adverse effects.</p>
4	Efekat akutnog izlaganja peroralno unetog akrilamida na histološke strukture želuca pacova soja Wistar / The effect of acute exposure to orally ingested acrylamide on histological structure of stomach in Wistar rats Ilić Sabo Jelena 04 July 2016 (has links) <p>Akrilamid je toksična hemijska supstanca koja ima vrlo &scaron;iroku primenu u hemijskoj industriji, a 2002. godine otkriveno je njegovo prisustvo u namirnicima bogatim skrobom koje se pripremaju na visokim temperaturama. U poslednjh desetak godina primećen je veliki porast gastrointestinalnih tegoba u ljudskoj populaciji. Cilj istraživanja bio je ispitati patohistolo&scaron;ke promene u tkivu želuca pacova soja Wistar izazvanih peroralnim aplikovanjem akrilamida i na taj način povući paralelu sa mogućim gastrointestinalnim tegobama nastalim kao posledica konzumiranja hrane bogate akrilamidom. U istraživanju je ispitivano 6 grupa od po 5 eksperimentalnih životinja (pacovi soja Wistar). Dve kontrolne grupe kojima je peroralno aplikovana destilovana voda i koje su žrtvovane posle 24h i 72h; dve eksperimentalne kojima je peroralno aplikovan akrilamid u dnevnoj dozi od 25 mg/kg i koje su žrtvovane posle 24h i 72h; dve eksperimentalne grupe kojima je peroralno aplikovan akrilamid u dnevnoj dozi od 50 mg/kg i koje su žrtvovane posle 24h i 72h. Na histolo&scaron;kom materijalu tkiva želuca primenjena je kvalitativna histolo&scaron;ka analiza pod svetlosnim mikroskopom, semikvantitativna procena tipa mucina u epitelnim ćelijama sluznice želuca, prisustvo limfocita i granulocita u sluznici želuca, stereolo&scaron;ka merenja pojedinih kompartmana zida želuca, linearna merenja broja i veličine ganglijskih ćelija u Maissner-ovom i Auerbach-ovom nervnom pleksusu, kao i broj mastocita u lamini propriji sluznice i podsluznici želuca. Dobijene vrednosti merenih parametara su potom statistički obrađene. Nastale promene na tkivu želuca pacova soja Wistar se ogledaju u vidu blagog direktnog o&scaron;tećenja povr&scaron;nog epitela sa propratnom blagom inflamatornom reakcijom i blagom degranulacijom mastocita. U Maissner-ovom i Auerbach-ovom nervnom pleksusu su smanjene volumenske gustine nervnih vlakana i ganglijskih ćelija, kao i broj i veličina ganglijskih ćelija. Direktno toksično delovanje na epitel dovodi do posledične obnove epitela, te je potvrđeno prisustvo nezrelijih oblika mukoproduktivnih ćelija koje sadrže kisele, AB pozitivne mucine. Ispitani inflamatorni i degenerativni parametri pokazuju pozitivnu korelaciju u odnosu na dozu i/ili dužinu ekspozicije akrilamidu. Primena akrilamida peroralno pokazala je da postoje patohistolo&scaron;ke promene na tkivu želuca u vidu direktnog toksičnog o&scaron;tećenja epitela, inflamatorne reakcije i o&scaron;tećenja nervnih pleksusa. Poznavanjem mehanizma delovanja ove toksične materije moguće je primeniti adekvatnu prevenciju u ishrani i izvr&scaron;iti odgovarajući izbor terapijskih metoda.</p> / <p>Acrylamide is a toxic chemical substance with wide implementation in chemical industry. In 2002 it was discovered the presence of acrylamide in foods rich in starch which are prepared at high temperatures. In the last ten years there is a large increase in gastrointestinal illnesses in human population. The aim of this study was to investigate the histopathological changes in the gastric tissue in Wistar rats induced with injection of oral acrylamide and thus draw a parallel with possible gastrointestinal problems arising as a result of the consumption of foods rich in acrylamide. The research was carried out 6 groups of 5 experimental animals (Wistar rats). Two control groups that are orally concomitant application of distilled water and which were sacrificed after 24h and 72h; two experimental groups which are orally administrated acrylamide in a daily dose of 25 mg / kg and that were sacrificed after 24h and 72h; two experimental groups which were orally administrated acrylamide in a daily dose of 50 mg / kg and that were sacrificed after 24h and 72h. On histological gastric tissue material is applied qualitative histological analysis by light microscopy, semi-quantitative assessment of the type of mucin in epithelial cells of the stomach lining, the presence of lymphocytes and granulocytes in gastric mucosa, stereological measurements of individual compartments of the stomach wall, linear measuring the number and size of ganglion cells in the Maissner and Auerbach's nerve plexus, and the number of mast cells in the lamina propria of the mucosa and in the submucosis of the stomach. Obtained values of measured parameters were statistically processed. Histological changes in the stomach tissue of Wistar rats are seen as a direct slight damage of the surface epithelium, with accompanynig mild inflammatory reaction and the degranulation of mast cells. The Meissner's and Auerbach's nerve plexus decreased volume density of nerve fibers and ganglion cells, as well as the number and size of the ganglion cells. Directly toxic effect on epithelium leads to the result of the reconstruction of the epithelium, which is confirmed by the presence of immature form of mucoproductive cells which contain acid, AB positive mucins. Examined inflammatory and degenerative parameters show a positive correlation with respect to dose and / or a time of exposition to acrylamide. Acrylamide oral application revealed that there are histologic changes in the stomach tissue in the form of a direct toxic damage to the epithelium, inflammatory reaction and damage to the nerve plexus. Knowing the mechanism of action of these toxic substances allows to apply adequate prevention in nutrition and make an appropriate choice of therapeutic methods.</p>
5	Strukturiranje polimernih mreža na osnovu akrilamida i akrilne kiseline / Structuring of polymer networks based on acrylamide and acrylic acid Erceg Tamara 28 September 2019 (has links) <p style="text-align: justify;">U ovom radu sintetisani su hidrogelovi na osnovu akrilamida i akrilne kiseline, radikalnom polimerizacijom, primenom konvencionalne i mikrotalasne metode sinteze. Varirani su početni odnosi monomera i udeo umreživača, u cilju ispitivanja uticaja sastava reakcione sme&scaron;e na svojstva dobijenih hidrogelova. Optimizovani su uslovi sinteze u mikrotalasnom polju kao brže, jednostavnije i ekonomičnije metode. U cilju uspostavljanja korelacije između mehanizma sinteze, strukture i svojstava dobijenih hidrogelova, primenom relevantnih metoda karakterizacije, upoređena su apsorpciona, reolo&scaron;ka, toplotna i strukturna svojstva hidrogelova dobijenih dvema metodama.                                           Ustanovljeno je da se mikrotalasnom metodom sinteze na brži i jednostavniji način uz smanjen utro&scaron;ak vremena i energije dobijaju hidrogelovi konkurentni onima koji se dobijaju konvencionalnim zagrevanjem u vodenom rastvoru. Drugi deo doktorata obuhvata sintezu hidrofilnih polimernih mreža na osnovu natrijum karboksimetilceluloze (NaCMC) i karboksilnih kiselina, od kojih je jedna serija sintetisana prožimanjem linearnim kopolimerima akrilamida i akrilne kiseline u cilju povećanja potencijala primene u floku-lacione svrhe. Rezultati ispitivanja svojstava bubrenja, strukturnih toplotnih i flokulacionih svojstava pokazali su međusobno slaganje. Dobijeni rezultati pokazali su da od primenjenih karboksilnih kiselina, linunska kiselina u udelu od 15% u odnosu na masu NaCMC daje hidrogelove najboljih svojstava. Kombinacijom ove mreže sa kopolimerom akrilamida i akrilne kiseline u masenom odnosu 10/90, stvara se teorijska platforma za dobijanja flokulanta koji bi mogao da pokaže visoku efikasnost u preči&scaron;ćavanju vode u kojoj dominiraju pozitivno naelektrisane čestice, pravilnim izborom parametara flokulacije.</p> / <p>In this paper, hydrogels based on acrylamide and acrylic acid were synthesized using conventional and microwave synthetic methods via free-radical polymerization. The initial monomers ratio and amount of crosslinking agent were varied in order to investigate the effect of the composition of the reaction mixture on the properties of the obtained hydrogels. The conditions of synthesis in the microwave field as faster simpler and more economical method have been optimized. In order to establish a correlation between the mechanism of synthesis, structure and properties of the obtained hydrogels using the relevant methods of characterization, the absorption, rheological, thermal and structural properties of the hydrogels obtained by the two methods were compared. It has been found that the microwave synthesis is a faster and simpler method, which enables reduced consumption of time and energy and produces hydrogels competitive to those ones obtained by conventional heating in aqueous solution. The second part of the thesis includes the synthesis of hydrophilic polymer networks based on sodium carboxymethylcellulose (NaCMC) and carboxylic acids, whereby one series is synthesized by interpenetration of the network using the linear acrylamide and acrylic acid copolymers in order to increase the potential application of hydrogels for flocculation purposes. The results of measurements of swelling, structural, thermal and flocculation properites have shown mutual agreement. The obtained results have shown that among applied carboxylic acids, citric acid in the amount of 15% per mass of NaCMC, has given the hydrogels with the best properties. The Combination of this network with a copolymer of acrylamide and acrylic acid in a mass ratio of 10/90 has created a theoretical platform for the production of flocculant which could show high efficacy in purifying of water dominated by positively charged particles.</p>

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